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<?xml version="1.0"?>
<!DOCTYPE archimedes SYSTEM "../dtd/archimedes.dtd" ><archimedes>      <info>        <author>Caverni, Raffaello</author>        <title>Storia del Metodo Sperimentale in Italia</title>        <date>1891</date>        


<place>Florence</place>         <translator></translator>        <lang>it</lang>              <cvs_file>caver_metod_020_it_1891.xml</cvs_file><cvs_version>1.11</cvs_version>        <locator>020.xml</locator>      </info>      <text>          <front>          </front>          <body>            <chap>        
<!-- begin english -->
<p type="main">

<pb xlink:href="020/01/001.jpg"/><s><foreign lang="en">350478 Storia Del Metodo Sperimentale Italia </foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>THE SOURCES OF SCIENCE<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>Editor-in-Chief: Harry Woolf<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/><emph type="italics"/>Willis K. </foreign></s>

<s><foreign lang="en">Shepard Professor of the History of <lb/>Science, The Johns Hopkins University<emph.end type="italics"/><emph.end type="center"/></foreign></s></p><pb xlink:href="020/01/002.jpg"/><p type="main">

<s><foreign lang="en"><emph type="center"/><emph type="bold"/><emph type="italics"/>Storia del Metodo <lb/>Sperimentale in Italia<emph.end type="italics"/><emph.end type="bold"/><emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>by RAFFAELLO CAVERNI<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>in Six Volumes<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>Volume I<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>WITH AN INTRODUCTORY NOTE BY <lb/>GIORGIO TABARRONI<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>THE SOURCES OF SCIENCE, NO. 134<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>JOHNSON REPRINT CORPORATION<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>NEW YORK LONDON 1972<emph.end type="center"/></foreign></s></p><pb xlink:href="020/01/003.jpg"/><p type="main">

<s><foreign lang="en"><emph type="center"/>Reproduced here is the Florence edition of 1891-1900.<emph.end type="center"/></foreign></s></p><figure id="id.020.01.003.1.jpg" xlink:href="020/01/003/1.jpg"/><p type="main">

<s><foreign lang="en"><emph type="center"/>Copyright &copy; 1972 by Johnson Reprint Corporation All rights reserved <lb/>Library of Congress Catalog Card Number: 70-178235<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>JOHNSON REPRINT CORPORATION<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>111 Fifth Avenue, New York, N.Y. 10003, U.S.A.<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>JOHNSON REPRINT COMPANY LTD.<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>Shipton Group House, 24/28 Oval Road, London, NW17DD, England<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/><emph type="italics"/>Printed in Italy<emph.end type="italics"/><emph.end type="center"/></foreign></s></p><pb xlink:href="020/01/004.jpg"/><p type="main">

<s><foreign lang="en"><emph type="center"/><emph type="bold"/><emph type="italics"/>Raffaello Caverni and his Work<emph.end type="italics"/><emph.end type="bold"/><emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>AN INTRODUCTORY NOTE BY GIORGIO TABARRONI<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>TRANSLATED BY BARBARA BIANCHI<emph.end type="center"/><pb xlink:href="020/01/005.jpg"/></foreign></s></p><pb xlink:href="020/01/006.jpg"/><p type="main">

<s><foreign lang="en">1. <emph type="italics"/>Validity of the work and scope of this edition.<emph.end type="italics"/> 2. <emph type="italics"/>Biographical <lb/>note.<emph.end type="italics"/> 3. <emph type="italics"/>Early writings.<emph.end type="italics"/> 4. <emph type="italics"/>Studies<emph.end type="italics"/> Sulla filosofia delle scienze <lb/>naturali <emph type="italics"/>(On the philosophy of natural science) and their banning by the <lb/>Congregation of the Holy Office.<emph.end type="italics"/> 5. <emph type="italics"/>Popular works.<emph.end type="italics"/> 6. <emph type="italics"/>The great<emph.end type="italics"/><lb/>Storia. </foreign></s>

<s><foreign lang="en">7. <emph type="italics"/>Caverni's last years.<emph.end type="italics"/> 8. <emph type="italics"/>Odyssey of the manuscripts.<emph.end type="italics"/><lb/>9. <emph type="italics"/>Conclusion.<emph.end type="italics"/></foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>1. VALIDITY OF THE WORK AND SCOPE OF THIS EDITION<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">The first edition of the work presented here in photographic reprint was of <lb/>modest proportions. </foreign></s>

<s><foreign lang="en">The author was a clergyman of the Florentine diocese, a <lb/>student of philosophy and the history of science, and when he died in early <lb/>1900 the work was suspended halfway through the sixth volume even though <lb/>a practically completed manuscript did exist. </foreign></s>

<s><foreign lang="en">Nor was it ever reprinted, <lb/>although our literature is anything but rich in this field, especially in that <lb/>turn-of-the-century period. </foreign></s>

<s><foreign lang="en">From a distance of seventy years one might well <lb/>ask whether Caverni's work is still valid or if it is not by now completely out&shy;<lb/>dated, to be exhumed only as a document of a bygone phase of the history of <lb/>science. </foreign></s></p><p type="main">

<s><foreign lang="en">Recently, however, a voice of great authority has assured us that the work <lb/>is still of cultural importance. </foreign></s>

<s><foreign lang="en">Eugenio Garin, in a lecture on <emph type="italics"/>La cultura <lb/>fiorentina nell'et&agrave; di Leonardo<emph.end type="italics"/> (Florentine culture in the age of Leonardo) <lb/>includes a penetrating and original opinion of Caverni, referring to <emph type="italics"/>La storia <lb/>del metodo sperimentale in Italia<emph.end type="italics"/> as &ldquo;a work wrongly forgotten.&rdquo; <lb/><lb/>For the <lb/>oblivion in which it has remained for so long, almost an unjust and mistaken <lb/>ostracism, has encouraged the persistence of the legend that it is an essentially <lb/>anti-Galilean work. </foreign></s>

<s><foreign lang="en">Actually, the critical perspective and the dispassionate <lb/>(even if, naturally, not infallible) examination of the sources that characterize <lb/>this work are clearly in contrast with the emphasis and tone of the writings of <lb/>the Italian Galileans who, from Viviani to Favaro, have felt they had to serve<gap/><lb/>unsolicited and superfluous, as the extreme apologists or defenders of Galileo<gap/><lb/>The latest representatives of this tradition, whom we cannot hesitate to cal<gap/><pb xlink:href="020/01/007.jpg" pagenum="viii"/>scarcely brilliant from an epistemological point of view, blamed Raffaello <lb/>Caverni as the sole individual responsible for certain reservations and limita&shy;<lb/>tions formulated at the beginning of the century, especially abroad, concerning <lb/>the validity and originality of Galileo's work. </foreign></s>

<s><foreign lang="en">They evidently did not realize <lb/>that one of the major causes of this truly anti-Galilean reaction lay, instead, <lb/>principally in their panegyrics and hagiographical essays. </foreign></s>

<s><foreign lang="en">The validity of <lb/>Caverni's writings today lies exactly in his having sensed that while in the past <lb/>crediting Galileo indiscriminately with everything worthwhile accomplished in <lb/>Italy from the end of the sixteenth century to the second half of the seventeenth <lb/>may have increased esteem for and diffusion of his works and thought, with <lb/>modern historians it could seriously compromise, as indeed has happened, his <lb/>authentic merits, in spite of their greatness. </foreign></s>

<s><foreign lang="en">It has been said and repeated by <lb/>his critics that Caverni has drastically stripped the laurels wreathing the fore&shy;<lb/>head of the great Tuscan scientist. </foreign></s>

<s><foreign lang="en">They have not understood that he has only <lb/>tried, instead, without false piety, to free the votive monument, erected to the <lb/>man with the best of intentions, of all its tinsel and gingerbread, that it might <lb/>better show its gold and gems. </foreign></s></p><p type="main">

<s><foreign lang="en">It must surely be opportune, therefore, to exhume this work. </foreign></s>

<s><foreign lang="en">We might <lb/>question, instead, the photographic reproduction of the original edition, with <lb/>its numerous typographical errors and incomplete indexes, without notes for <lb/>clarification or cross-reference, without the verification and completion of the <lb/>bibliographical references and, above all, without the necessary indication of the <lb/>inevitable mistakes the author made in his exegesis of the sources, in which <lb/>task he was a real pioneer. </foreign></s>

<s><foreign lang="en">In addition, perhaps it would have been possible to <lb/>bring to light that part of the manuscript still, unfortunately, unprinted. </foreign></s>

<s><foreign lang="en"><lb/>However, a new edition that would satisfy such a vast and ambitious program <lb/>implies no small amount of labor, which besides requiring a considerable amount <lb/>of time would be hampered by the lack of a congruous number of copies of the <lb/>text. </foreign></s>

<s><foreign lang="en">The six volumes of this work have become a rarity: few libraries possess <lb/>any of them; very few have all of them&mdash;not even the Nazionale of Florencel <lb/>Let us consider this present undertaking then as the first step toward a new, <lb/>more dispassionate study of the work and toward a broader diffusion of it, so <lb/>that we may have, in the near future, that new, corrected edition which per&shy;<lb/>haps Caverni himself, who died at the peak of maturity, had hoped to prepare. </foreign></s>

<s><foreign lang="en"><lb/>And we need not exclude in that event a more complete rendering of the sixth <lb/>volume left truncated at the end of an even numbered page, right in the middle <lb/>of a sentence. </foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>2. BIOGRAPHICAL NOTE<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">Raffaello Caverni led a life of the greatest simplicity. </foreign></s>

<s><foreign lang="en">Aldo Mieli, presenting a <lb/>series of articles for and against the <emph type="italics"/>Storia del metodo sperimentale<emph.end type="italics"/> in one of the <pb xlink:href="020/01/008.jpg" pagenum="ix"/>first-year issues of his <emph type="italics"/>Archivio,<emph.end type="italics"/> sums up his life in less than ten lines, and says <lb/>practically all there is to say. <lb/><lb/>Yet, Martini <lb/><lb/>in 1902, Orlando <lb/><lb/>in 1906, and <lb/>Giovannozzi <lb/><lb/>in 1910, without producing any salient facts, have enriched the <lb/>brief, recorded data with notes on his character and with a few significant <lb/>episodes which serve today to render his figure lifelike and to shed further light <lb/>on his already clear personality. </foreign></s>

<s><foreign lang="en">The sense of the man that one gathers from <lb/>this information, which might be thought to be biased since it is handed down <lb/>to us by men who were his devoted friends, is fully confirmed by accounts one <lb/>can still hear from the lips of the old parishioners of Quarate in the Ema Valley, <lb/>or from Lamberto Caverni, the oldest of his grandnephews who was only a few <lb/>years old when Don Raffaello died, but who remembers clearly everything his <lb/>father, Egisto, had to tell about that uncle. </foreign></s>

<s><foreign lang="en">Some of these details and others <lb/>besides can be checked against the documents and papers, although there are <lb/>some, together with a great many manuscripts, which the heirs jealously keep <lb/>to themselves. </foreign></s></p><p type="main">

<s><foreign lang="en">Raffaello Caverni was born in San Quirico di Montelupo in a house on the <lb/>Via Pisana. </foreign></s>

<s><foreign lang="en">The place is now marked by a memorial plaque with an epigraph <lb/>by Father G. Giovannozzi, placed there in July 1902, which following the <lb/>unfortunate cultural customs of those times remembers him in a rather <lb/>infelicitous manner as &ldquo;most celebrated writer ... with German erudition <lb/>and Italian genius.&rdquo; Such rhetoric hardly suits his work which, though not <lb/>always polished and rigorous, is brilliant, sagacious, and often piercing&mdash;in a <lb/>word, truly Tuscan. </foreign></s>

<s><foreign lang="en">The Registry of baptisms in Pieve di Montelupo shows <lb/>that <emph type="italics"/>Raffaello Gregorio<emph.end type="italics"/> (the second name perhaps in honor of the reigning <lb/>Pope) <emph type="italics"/>Gaspero, son of Vincenzo son of Pietro Caverni and Assunta Mancioli<emph.end type="italics"/><lb/>was born in <emph type="italics"/>S. </foreign></s>

<s><foreign lang="en">Quirico at the Ambrogiana<emph.end type="italics"/> (the lovely Medici villa now an <lb/>asylum for the criminal insane) <emph type="italics"/>on March 12, 1837, at 8:00 p.m.<emph.end type="italics"/> He was the <pb xlink:href="020/01/009.jpg" pagenum="x"/>third of seven children of a modest family which owned a kiln and delivered <lb/>bricks and other construction material to builders, especially in Florence, with <lb/>their own <emph type="italics"/>barocci,<emph.end type="italics"/> the traditional two-wheeled carts which, horse-drawn and <lb/>balanced, have for centuries performed this task over the greater part of the <lb/>Italian countryside. </foreign></s>

<s><foreign lang="en">Less sturdy than the other children, he was sent to the town <lb/>school where, it seems, he distinguished himself so well that at the age of <lb/>thirteen, having already decided on his vocation, he went to Florence to study. </foreign></s>

<s><foreign lang="en"><lb/>Since there was no seminary then, he became one of the young clergy of the <lb/>Cathedral and enrolled in the Collegio Eugeniano, an excellent school of <lb/>humanistic leaning, where he completed the entire course corresponding to <lb/>what would later be the Gymnasium. </foreign></s>

<s><foreign lang="en">His success there seemed to point to the <lb/>concinuation of literary studies, but Caverni had already made another choice. </foreign></s>

<s><foreign lang="en"><lb/>For three years after the Collegio he attended the public Scuole Pie, run by the <lb/>Scolopian Fathers at S. Giovannino. </foreign></s>

<s><foreign lang="en">There he received a basis foundation in <lb/>what were to become his favorite subjects: philosophy, taught by the Rosminian <lb/>Father Zini, and physics with Father Cecchi who together with Father Antonelli <lb/>was to furnish the loggia dei Lanzi in 1860 with a pair of exceptional instru&shy;<lb/>ments: a thermometer and a barometer with a face of more than 1.5 meters. </foreign></s>

<s><foreign lang="en"><lb/>Then, instead of going to the University, for a few years he attended the <lb/>Istituto Ximeniano, also run by the Scolopians, where he had Antonelli for <lb/>astronomy and higher mathematics and Father Barsanti for mechanics and <lb/>hydraulics. </foreign></s>

<s><foreign lang="en">And thus he became a priest with the hobby of philosophy and <lb/>science, following an inclination which seems traditional in the Florentine <lb/>clergy&mdash;the desire to reconcile what appears to be irreconcilable! </foreign></s></p><p type="main">

<s><foreign lang="en">During the school year 1859-60, at the same time that the Granducal <lb/>government failed, the Archbishop of Florence sent him as professor of philos&shy;<lb/>ophy and mathematics to the Seminary of Firenzuola, a sort of citadel in a <lb/>gorge in the Apennines, exactly halfway between Florence and Bologna. </foreign></s>

<s><foreign lang="en">There <lb/>he was ordained on the second of June 1860 and there he spent, in great <lb/>serenity, a period which the young priests of the diocese considered a kind of <lb/>severe penance. </foreign></s>

<s><foreign lang="en">During the ten years he remained there he studied nature with <lb/>enthusiasm, gaining thereby a rapid and complete maturity while filling entire <lb/>notebooks with observations, records, and meditations. </foreign></s>

<s><foreign lang="en">But at the end of 1870, <lb/>shortly after Porta Pia, he was at last recalled from his exile of sorts and assigned <lb/>to a parish about 12 kilometers from Florence. </foreign></s>

<s><foreign lang="en">As Father Givannozzi has <lb/>observed, this parish was small, well supplied, and conveniently close to the <lb/>libraries of the city, and this made it possible for him in the course of a simple <lb/>life to return again with zeal to his favorite studies, but without neglecting his <lb/>ministry. </foreign></s>

<s><foreign lang="en">In that place, even less populous today, he is still remembered <lb/>with admiration, almost veneration, by the oldest inhabitants who used to <lb/>study catechism with him. </foreign></s>

<s><foreign lang="en">Giovannozzi observes that he was &ldquo;as good a <lb/>priest as he was a diligent scholar.&rdquo; But he found neither one nor the other <lb/>occupation without its thorns and difficulties. </foreign></s></p><pb xlink:href="020/01/010.jpg" pagenum="xi"/><p type="main">

<s><foreign lang="en"><emph type="center"/>3. EARLY WRITINGS<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">In 1872 Caverni was ready with his first publications. </foreign></s>

<s><foreign lang="en">There are the curious <lb/>&ldquo;Ricreazioni scientifiche&rdquo; (scientific pastimes), a column at once instructive <lb/>and amusing where science is handled in a conversational and easily com&shy;<lb/>prehensible manner, while the part reserved for the history of science (for <lb/>example, to science in Dante) is characterized by profound research and a <lb/>rigorous exposition that is not always easy and never elementary. </foreign></s>

<s><foreign lang="en">These articles, <lb/>which appeared periodically, were first printed in the magazine <emph type="italics"/>La Scuola<emph.end type="italics"/> that <lb/>had just been founded by Augusto Alfani (another Florentine who knew how <lb/>to reconcile faith and science and, even more daring, was among those who <lb/>hoped to see closer ties between Church and State). They were continued in the <lb/>periodical <emph type="italics"/>Letture di famiglia<emph.end type="italics"/> and collected under the same title in a volume <lb/>published in 1882 which Giovannozzi in 1910 declared was already almost im&shy;<lb/>possible to find. </foreign></s>

<s><foreign lang="en">I myself have never seen it even mentioned in a catalogue. </foreign></s></p><p type="main">

<s><foreign lang="en">Another series of articles appeared in the same magazines in almost the same <lb/>period, but was concluded more rapidly. </foreign></s>

<s><foreign lang="en">This series was entitled &ldquo;Consigli <lb/>sopra allo studio delle lettere a un giovanetto&rdquo; (advice to a young man on the <lb/>study of literature) and was published in volume form in 1879 with the title <lb/><emph type="italics"/>Dell'arte dello scrivere<emph.end type="italics"/> (on the art of writing). (Unfortunately, the copy at the <lb/>Nazionale of Florence was a victim of the flood.) Together with these, Caverni <lb/>also published studies of Dante's physics which were never reprinted alone. </foreign></s>

<s><foreign lang="en">In <lb/>1874 his first book appeared: <emph type="italics"/>Problemi naturali di Galileo e della sua scuola<emph.end type="italics"/><lb/>(natural problems of Galileo and his school), published by Sansoni and, like his <lb/>other works, not easily found today. </foreign></s>

<s><foreign lang="en">His <emph type="italics"/>Dizionarietto di voci e modi dell'uso <lb/>popolare toscano nella Divina Commedia<emph.end type="italics"/> (little Dictionary of Tuscan words and <lb/>phrases in the Divine Comedy), published in 1877, was however destined to <lb/>enjoy a certain popularity. </foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>4. STUDIES <emph type="italics"/>Sulla filosofia delle scienze naturali<emph.end type="italics"/> (ON THE PHILOSOPHY OF <lb/>NATURAL SCIENCE) AND THEIR BANNING BY THE CONGREGATION OF THE <lb/>HOLY OFFICE<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">In the meantime, the <emph type="italics"/>Rivista Universale<emph.end type="italics"/> (universal magazine) began to appear <lb/>in Florence, soon changing its letterhead to <emph type="italics"/>Rassegna Nazionale<emph.end type="italics"/> (national <lb/>review). The Treccani terms it the magazine of conservative Catholics, but <lb/>Giovannozzi is more detailed and precise, recalling it as the periodical that was <lb/>the &ldquo;champion, for many years the only one, of the struggle for faith and <lb/>nationality indissolubly united,&rdquo; when during the long papacy of Leon XIII <lb/>(1878-1903) such a program was considered almost nonsensical and little less <lb/>than heretical. </foreign></s>

<s><foreign lang="en">Caverni immediately took advantage of this arena and in 1875 <lb/>and 1876 published a series of epistemological studies which Giovannozzi <lb/>properly calls &ldquo;his most beautiful work.&rdquo; The original title was <emph type="italics"/>Sulla filosofia<emph.end type="italics"/><pb xlink:href="020/01/011.jpg" pagenum="xii"/><emph type="italics"/>delle scienze naturali<emph.end type="italics"/> (on the philosophy of natural science), changed&mdash;who <lb/>knows why&mdash;with publication in volume form in 1877 into the less significant <lb/><emph type="italics"/>De'nuovi studi della filosofia, Discorsi di Raffaello Caverni a un giovane studente<emph.end type="italics"/><lb/>(on the new studies of philosophy, conversations of Raffaello Caverni with a <lb/>young student). Here he maintained that philosophy too is a science of observa&shy;<lb/>tion, that is, basically experimental, and criticized both those philosophers who <lb/>want to consider man prescinding from any scientific preparation and without <lb/>any knowledge of physiology in particular and those scientists who see in man <lb/>only his material being. </foreign></s>

<s><foreign lang="en">But the central theme of this treatise is delicate and <lb/>controversial for his times. </foreign></s>

<s><foreign lang="en">Caverni undertook a critical examination of <lb/>Darwin's theory of evolution as contained in <emph type="italics"/>The Descent of Man,<emph.end type="italics"/> which had <lb/>appeared in 1871. A subtitle of the third chapter declared &ldquo;That the new <lb/>doctrine of Darwin and natural science ought not frighten the faithful who <lb/>should be allowed to cultivate them in all serenity and we too, confuting them <lb/>where necessary, should cultivate them with love.&rdquo; His program was clear but <lb/>hardly in harmony with the position taken by the Catholic world. </foreign></s>

<s><foreign lang="en">And thus, <lb/>while the articles printed in the magazine miraculously passed, not so the book <lb/>which was put on the Index with a decree dated July 1, 1878. Father Gio&shy;<lb/>vanozzi, particularly competent in the matter, wrote, &ldquo;I believe the prohibition <lb/>of the book was due not to its defense of the evolutionary hypothesis, but to the <lb/>rather sharp and caustic attacks against institutes, methods and persons of the <lb/>ecclesiastical world.&rdquo; <lb/><lb/>In any case, this episode marked the parting of ways&mdash;a <lb/>break only on a cultural plane, of course, yet even so, sharp and precise&mdash;with <lb/>a rejection which was to be constant and unhesitating of a certain &ldquo;tradition&rdquo; <lb/>that Caverni found stale and moldy. </foreign></s>

<s><foreign lang="en">For even after the decision of the Con&shy;<lb/>gregation of the Index, his ideas did not change essentially. </foreign></s>

<s><foreign lang="en">In the <emph type="italics"/>Rassegna <lb/>Nazionale<emph.end type="italics"/> he continued to publish articles on an analogous subject, <emph type="italics"/>Sull' <lb/>antichit&agrave; dell'uomo<emph.end type="italics"/> (on the antiquity of man); in this series, which appeared in <lb/>volume form in 1881, he concluded, as in his preceding work, that the faithful <lb/>may tranquilly attend geologists'debates on the matter. </foreign></s>

<s><foreign lang="en">The substance is more <lb/>or less the same. </foreign></s>

<s><foreign lang="en">Perhaps this time he simply refrained from those biting <lb/>allusions to some colleagues which, to tell the truth, he brings off so skillfully. </foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>5. POPULAR WORKS<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">From 1884 to 1888 Raffaello Caverni dedicated himself to scientific populariza&shy;<lb/>tion, without doubt a congenial genre. </foreign></s>

<s><foreign lang="en">For his task he put aside those regal and <lb/>curial robes he had donned to write of philosophy and the history of science and <lb/>treated the subjects of physics and natural science in limpid, fluent language, <lb/>presenting orderly ideas and familiar images. </foreign></s>

<s><foreign lang="en">For this reason the environment, <lb/>mentality, and customs of his times enter freely into these pages and they <pb xlink:href="020/01/012.jpg" pagenum="xiii"/>reflect more than others the years that have passed. </foreign></s>

<s><foreign lang="en">Nonetheless, they still <lb/>make pleasurable reading and, more important, they have remained in the <lb/>memory of those who read them as children: I have seen eyes shine at their <lb/>mention. </foreign></s></p><p type="main">

<s><foreign lang="en">These writings originated in 1884 when the ex-publishing company <lb/>Lemonnier decided to produce a &ldquo;Library for young girls&rdquo; (even this label <lb/>conveys at once the sense of bygone years) and asked Caverni for a brief book <lb/>on elementary physics. </foreign></s>

<s><foreign lang="en">He gave them <emph type="italics"/>L'estate in montagna<emph.end type="italics"/> (summer in the <lb/>mountains), a gentle book for young people whose subject is woven into a <lb/>delicate and ingenuous love story. </foreign></s>

<s><foreign lang="en">A young invalid girl finds in the mountains <lb/>health and her young man, the author of popular notes on physics which have <lb/>amused and sustained her during the long months of her solitary convalescence. </foreign></s>

<s><foreign lang="en"><lb/>This little volume with drawings by Mazzanti, popular illustrator of Collodi's <lb/>books, was well received and reached a third edition, which encouraged its <lb/>author to continue. </foreign></s>

<s><foreign lang="en">At two-year intervals it was followed by <emph type="italics"/>Tra il verde e i <lb/>fiori<emph.end type="italics"/> (among the greens and flowers), a book on botany published in the same <lb/>series and <emph type="italics"/>Cogli occhi per terra<emph.end type="italics"/> (with eyes on the ground), dedicated to <lb/>mineralogy and published in Paggi's &ldquo;Biblioteca Scolastica&rdquo; (scholastic library). <lb/>Pursuit of this hobby, as we might call it, was for Caverni a singular prepara&shy;<lb/>tion for his most important work and perhaps an interlude during its actual <lb/>creation. </foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>6. THE GREAT <emph type="italics"/>Storia<emph.end type="italics"/><emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">Since in this reprint, as in the 1890 version, the <emph type="italics"/>Relazione della Giunta del R. </foreign></s>

<s><foreign lang="en"><lb/>Istituto Veneto deputata all'esame dei lavori presentati al concorso della <lb/>Fondazione Tomasoni<emph.end type="italics"/> (report of the Committee of the Royal Venetian In&shy;<lb/>stitute for the examination of the works presented for the Tomasoni Foundation <lb/>contest) precedes the text, readers are referred to that ample account for all <lb/>information regarding the genesis of the <emph type="italics"/>Storia del metodo sperimentale in <lb/>Italia<emph.end type="italics"/> (history of the experimental method in Italy) and its well-deserved <lb/>success in that contest whose prize was a sum roughly the equivalent of two <lb/>years'salary of a <emph type="italics"/>liceo<emph.end type="italics"/> professor! The concise comment on the entire work <lb/>found in the second part of that <emph type="italics"/>Relazione<emph.end type="italics"/> is particularly interesting. </foreign></s>

<s><foreign lang="en">We know, <lb/>from the draft of a letter kept by the heirs, that the committee&mdash;and for it the <lb/><emph type="italics"/>relatore,<emph.end type="italics"/> Antonio Favaro&mdash;made ample use of this critical summary in pre&shy;<lb/>paring the larger work for publication. </foreign></s>

<s><foreign lang="en">It seems that the author himself had <lb/>been requested to provide the summary when awarded the prize since it had <lb/>been impossible to read all the three thousand folio pages thickly covered with <lb/>script which he had submitted. </foreign></s>

<s><foreign lang="en">This contest, announced in 1880, had expired <lb/>March 31, 1889 when, after a first session in 1885, neither of the two works <lb/>presented had been found worthy of the prize. </foreign></s>

<s><foreign lang="en">The judges, more than a year <lb/>later in the solemn session of May 25, 1890, proclaimed that work the winner <pb xlink:href="020/01/013.jpg" pagenum="xiv"/>which had for its motto a tercet of Dante, the one (Paradise, II, 94-96) in the <lb/>learned canto on the lunar spots where Beatrice exalts Experimentation <lb/>&ldquo;which is the spring for the rivers of your arts.&rdquo; In the first part of the <lb/><emph type="italics"/>Relazione,<emph.end type="italics"/> which displays the unmistakable style and spirit of Favaro, there <lb/>is sincere praise and a warm appreciation of Caverni's monumental work. </foreign></s>

<s><foreign lang="en"><lb/>However, the <emph type="italics"/>relatore<emph.end type="italics"/> wants to make it clear (p. </foreign></s>

<s><foreign lang="en">12) that it &ldquo;did not seem in <lb/>our eyes altogether free of error.&rdquo; And thus begins that series of criticisms that <lb/>will with time gather impetus, increasing and thundering like an avalanche. <lb/></foreign></s>

<s><foreign lang="en">&ldquo;As concerns the sources, it is said to be somewhat wanting in knowledge of <lb/>the foreign ones,&rdquo; but this is the least of it; there is worse. </foreign></s>

<s><foreign lang="en">The work is found <lb/>to reflect &ldquo;a tendency to be too easily infatuated with the novelty of the con&shy;<lb/>clusions,&rdquo; and there is the suggestion that &ldquo;perhaps alarmed by the unjust <lb/>opinion of those who wished to exalt Galileo to the prejudice of all his con&shy;<lb/>temporaries, he seems almost always on guard against conclusions unduly <lb/>favorable to the supreme philosopher.&rdquo; And after some examples, for a few of <lb/>which such reservations can be accepted, the committee concludes ingenuously, <lb/>&ldquo;And this we point out fully certain the author, asked to better ponder these <lb/>matters, shall want to change his mind.&rdquo; Evidently they had not reckoned with <lb/>the character of Prior Caverni (although it shows in every page of his <emph type="italics"/>Storia<emph.end type="italics"/>): <lb/>he was, by general consensus, most pious, patient, and diligent in his ministry, <lb/>but bizarre and touchy as a man, extremely proud and intolerant of any <lb/>restriction of his liberty as a scholar. </foreign></s></p><p type="main">

<s><foreign lang="en">In the brief memorial which he delivered on February 25, 1900 at the Reale <lb/>Istituto Veneto, shortly after Caverni's death, Favaro says bitterly, &ldquo;Such <lb/>criticism, opportunely exemplified and applied, was not graciously received by <lb/>the author. </foreign></s>

<s><foreign lang="en">Indeed, at the time of publication he increased the dose in the <lb/>passages that had been pointed out to him....&rdquo; And he is careful to note that <lb/>&ldquo;the five volumes [the sixth, uncompleted, was to appear posthumously that <lb/>year] of the <emph type="italics"/>Storia del metodo sperimentale in Italia<emph.end type="italics"/> published by Caverni have <lb/>very little in general and nothing in many places to do [sic] with the work <lb/>submitted to the Institute and by it judged worthy of the prize.&rdquo; Favaro returned <lb/>to this subject in 1907 in his essay <emph type="italics"/>Antichi e moderni detrattori di Galileo<emph.end type="italics"/><lb/>(ancient and modern detractors of Galileo) published in the February 16th <lb/>issue of <emph type="italics"/>La Rassegna Nazionale<emph.end type="italics"/> that year and written in answer to &ldquo;a tendency <lb/>to renew Arago's accusations in different form, but with even greater acrimony, <lb/>with the addition of new and numerous points (!)&rdquo; Although in the conclusion, <lb/>alluding to Caverni, he recalls that &ldquo;We had promised ourselves not to lift the <lb/>veil from this shabby display since it seemed to us only charitable to ignore the <lb/>outbursts of a most great mind who let himself be led astray by personal motives <lb/>[his exclusion from the committee for the National Edition of the Works of <lb/>Galileo] to the point of striking one of our most pure and genuine glories...,&rdquo; <lb/>he had already aired his long repressed grievances. </foreign></s>

<s><foreign lang="en">The beginning of the seventh <lb/>paragraph, which ends this essay, reads: &ldquo;Except that it would be hardly tactful <pb xlink:href="020/01/014.jpg" pagenum="xv"/>of us to lament foreigners'lack of reverence towards Galileo; none of them has <lb/>reached the point of one Italian who seemed to have taken upon himself the <lb/>wretched task of stripping all he could of the laurels that embrace the im&shy;<lb/>mortal brow of the restorer of the experimental method and in some ponderous <lb/>volumes in which he set himself to weave its history, he has spared no low <lb/>insult nor poisonous insinuation to damage the dead in order to spite the <lb/>living&rdquo;! The rest is in the same tone. </foreign></s>

<s><foreign lang="en">I think I can identify in this harsh <lb/>accusation the echo of much of the criticism and even of the charges which <lb/>were brought against the incautious <emph type="italics"/>rapporteur<emph.end type="italics"/> of the Committee for the <lb/>Tomasoni Prize instituted so few years after the breach of Porta Pia and <lb/>destined <emph type="italics"/>&ldquo;to whomsoever shall better tell the history of the experimental method <lb/>in Italy,&rdquo;<emph.end type="italics"/> certainly presuming that the new atmosphere would lead to a freer, <lb/>more open condemnation of the old obscurantism. </foreign></s></p><p type="main">

<s><foreign lang="en">The news that the winner was a parish priest from some little hill town in <lb/>Tuscany must have aroused much disappointment and not a little annoyance! <lb/>But actually Favaro and his accusers were not altogether wrong. </foreign></s>

<s><foreign lang="en">Giovannozzi, <lb/>who has been the only defender of Caverni, also admits that &ldquo;Strange and <lb/>almost incredible, there seems to linger in all this work an anti-Galilean spirit; <lb/>a subtle irony pervades it now and then, the intent to make use of every <lb/>opportunity to strip the laurels of the great old man of Arcetri, a frenzy to find <lb/>him at fault, to diminish his merits in order to attribute them to others, to <lb/>accuse him of having wanted to appropriate them all for himself.&rdquo; He does <lb/>attempt, timidly, an explanation: &ldquo;Who knows? </foreign></s>

<s><foreign lang="en">Perhaps he wanted to guard <lb/>against an excessive admiration or idolatry and ended up falling into the <lb/>opposite defect.&rdquo; And he seems to abstain from an all-out defense almost as <lb/>though afraid of being more damaging than useful to his friend and teacher. </foreign></s>

<s><foreign lang="en"><lb/>The reasons justifying Caverni only in part, but which do explain his behavior <lb/>as that of a man of terrible, albeit resolute character rather than that of a <lb/>factious priest as Timpanaro would have him, <lb/><lb/>are also mentioned fleetingly <lb/>by Giovannozzi. </foreign></s>

<s><foreign lang="en">There are three main ones. </foreign></s>

<s><foreign lang="en">The recommendation of the <lb/>Committee that he mitigate his opinion of Galileo must have vexed Caverni <lb/>greatly; he must have felt that they had not tried to understand his labors. </foreign></s>

<s><foreign lang="en"><lb/>Second, he was immediately reminded that he had to publish the <emph type="italics"/>whole<emph.end type="italics"/> work <lb/>at his own expense in order to have the prize, according to the instructions of <lb/>the testator who certainly had not imagined that publication would have meant <lb/>an expense far surpassing the amount of the prize. </foreign></s>

<s><foreign lang="en">And last, he was profoundly <lb/>embittered and disappointed by the news that reached him shortly after he <lb/>learned of the prize thus conditioned, that his name had been excluded from the <lb/>committee for the monumental Galilean edition. </foreign></s>

<s><foreign lang="en">This certainly was not <pb xlink:href="020/01/015.jpg" pagenum="xvi"/>ambition in a man who, to his archbishop's displeasure, went about with his hat <lb/>in rags and his pants too short, like a so-called second-rate priest and who had <lb/>refused an offer from the university and membership in the Accademia dei <lb/>Lincei. </foreign></s></p><p type="main">

<s><foreign lang="en">Having dedicated most of his energy and the greater part of his life for <lb/>almost thirty years to the study of thousands of Galilean documents, his <lb/>profound knowledge of the thought and works of the great master of the <lb/>experimental method, his unique familiarity with the surviving instruments <lb/>and with the language of Galileo must certainly have led Caverni to feel that <lb/>it was at once his right and his duty to sit on that committee. </foreign></s>

<s><foreign lang="en">Disappointment <lb/>and bitterness are bad counselors and temptation does not spare even the <lb/>ministers of the Lord. </foreign></s>

<s><foreign lang="en">And thus, even if I do not feel I can agree (in the spirit <lb/>of the images and comparisons of Favaro) that Caverni intended to make <lb/>poisonous insinuations and basely insult the dead Galileo, there is no doubt <lb/>that Favaro is right when he accuses Caverni of having wanted to spite the <lb/>living. </foreign></s>

<s><foreign lang="en">In modifying his early manuscript (the so-called Venetian manuscript), <lb/>in the end he exaggerated and in some places was carried away by the spirit <lb/>of criticism at the expense of historic truth and calm judgment. </foreign></s>

<s><foreign lang="en">This is the <lb/>consequence of a deprecable exasperation, that exasperation which often over&shy;<lb/>comes candid souls! </foreign></s></p><p type="main">

<s><foreign lang="en">As for publication, it was only possible thanks to the assistance, which <lb/>Giovannozzi characterizes as &ldquo;munificent,&rdquo; of commendator Antonio Civelli, <lb/>whose firm published the democratic newspaper <emph type="italics"/>Il Corriere italiano,<emph.end type="italics"/> owned the <lb/>comparable Milanese paper <emph type="italics"/>La Lombardia<emph.end type="italics"/> and the Veronese <emph type="italics"/>L'Adige,<emph.end type="italics"/> and who <lb/>was known, among other things, for having published the <emph type="italics"/>Dizionario corografo <lb/>dell'Italia<emph.end type="italics"/> (chorographic dictionary of Italy). The first volume appeared in 1891 <lb/>and the relative scarcity of reviews leads us to think that it was met with <lb/>suspicion by both the right and the left. </foreign></s>

<s><foreign lang="en">One voice, however, rose clear and <lb/>competent to review it at such length that the &ldquo;Cenno bibliografico&rdquo; (biblio&shy;<lb/>graphical note) was in reality the main article of the April 1892 issue of the <lb/>magazine <emph type="italics"/>Il Pensiero italiano<emph.end type="italics"/> (Italian thought). <lb/><lb/>That well-balanced and <lb/>impartial voice was Giovanni Virginio Schiaparelli's. </foreign></s>

<s><foreign lang="en">Director of the Brera <lb/>Observatory, he was internationally known as an astronomer and also as a <lb/>profound commentator on the writings and documents of ancient astronomy. </foreign></s>

<s><foreign lang="en"><lb/>In judging Caverni's work he seeks no compromise or halfway measures: the <lb/>errors exist, rather serious ones at that, but the merits are such that the rest <lb/>seems of secondary importance. </foreign></s>

<s><foreign lang="en">He says in the beginning, &ldquo;... no one in the <lb/>history of science and certainly never in the history of practical science was <lb/>ever granted the liberty to write without practical knowledge of his subject.&rdquo; <lb/>But &ldquo;it seems that the gifts of the great scientist and those of the judicious <lb/>historian, elegant and erudite, have rarely been reconciled in the same person.&rdquo; <pb xlink:href="020/01/016.jpg" pagenum="xvii"/>And thus &ldquo;we must consider it quite a rare event and receive with all the <lb/>more satisfaction this <emph type="italics"/>Storia del metodo sperimentale in Italia,<emph.end type="italics"/> whose author <lb/>shows himself not unequal both in scholarship and narrative art to the high <lb/>and difficult task he sets himself.&rdquo; After masterfully condensing and com&shy;<lb/>menting on the vast contents of the part already published, Schiaparelli, <lb/>expert of ancient and modern science that he was, comments on certain of <lb/>Caverni's opinions and &ldquo;demonstrations&rdquo;: &ldquo;He feels a strong attraction to <lb/>some of his personages and just as pronounced an antipathy for others His <lb/>enthusiasm for Plato is truly excessive ... without considering that Platonic <lb/>speculation is the exact antithesis of the experimental method.... On the <lb/>contrary, according to Caverni, Aristotle is the evil star,&rdquo; while &ldquo;it is commonly <lb/>held that that great thinker was instead one of the greatest observers of <lb/>antiquity and not even altogether unfamiliar with the art of experimentation. <lb/>... Obviously Caverni has confused Aristotle with the peripatetics of low <lb/>extraction who were contemporaries of Galileo.&rdquo; (We can readily agree with <lb/>Schiaparelli that Caverni, who never did things halfway, exaggerated some&shy;<lb/>what in refusing to recognize any Aristotelian components in the currents of <lb/>thought that determined the scientific method. </foreign></s>

<s><foreign lang="en">As for Plato, however, para&shy;<lb/>doxical as it may seem, we must agree with Caverni who sees him as the true, <lb/>great inspirer of the decisive turn of knowledge from Copernicus to Galileo. </foreign></s>

<s><foreign lang="en"><lb/>Plato, in fact, scorned the casual and unconditioned <emph type="italics"/>experience<emph.end type="italics"/> of our senses, not <lb/><emph type="italics"/>experimentation<emph.end type="italics"/> which in its artificiality is a completely different thing and is <lb/>intimately bound to abstractions of the Platonic type!) At this point close to <lb/>the end of his long review, the great astronomer of Brera, after saying &ldquo;I have <lb/>not found another work comparable to this in our scientific literature, unless it <lb/>be the <emph type="italics"/>Storia delle Matematiche in Italia<emph.end type="italics"/> by Gugliemo Libri,&rdquo; comes to the <lb/>burning question, that of the so-called anti-Galilean Caverni: &ldquo;He is a great <lb/>admirer of the science of Galileo, but this does not prevent him from presenting <lb/>the nature of it in a paradoxical light. </foreign></s>

<s><foreign lang="en">According to Caverni, Galileo was a <lb/>common egoist, a scientific pirate, constantly spying for the opportunity to rob <lb/>his predecessors, his contemporaries, his friends, his disciples, of the merit of <lb/>their inventions and discoveries, to attribute everything to himself ... to be <lb/>the only King in the realm of the new science. </foreign></s>

<s><foreign lang="en">And with this accusation, <lb/>Caverni calls for a new trial of Galileo, quite different from the ones he under&shy;<lb/>went during his lifetime and one which no one would have ever thought of.... <lb/>He takes it upon himself to strip as much as possible the laurels which circle the <lb/>brows of the great old man of Arcetri and this constant concern sometimes leads <lb/>to curious errors.... Fortunately these errors in judgment, which one en&shy;<lb/>counters here and there in the <emph type="italics"/>Discorso preliminare,<emph.end type="italics"/> occur more rarely in the <lb/>specific part of the work.&rdquo; (Actually, only the first volume had by then <lb/>appeared.) &ldquo;And let all this be said not for the mania of finding fault, of looking <lb/>for spots on the sun, but to show that the praises of Caverni's work given here <lb/>are the result of an impartial and pondered study of it.&rdquo; And reviewing the <pb xlink:href="020/01/017.jpg" pagenum="xviii"/>plan Caverni gave of the whole work, he concludes, almost as though he thought <lb/>the ambitious program might remain unfinished, &ldquo;But whatever may come of <lb/>this, what he has already done gives him the right to consider his work as the <lb/>greatest body of scientific history Italian literature can boast.&rdquo; </foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>7. CAVERNI'S LAST YEARS<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">For publication, Caverni completely rewrote the contest manuscript, adding, <lb/>amplifying, completing, and perhaps sometimes spoiling (Favaro <lb/><lb/>in an essay <lb/>of 1919 demonstrates that the most malicious and unfounded accusation <lb/>against Galileo, who was supposed to have had from Castelli the first news of the <lb/>phases of Venus, was not in the <emph type="italics"/>Venetian manuscript<emph.end type="italics"/> because it was &ldquo;an <lb/>addition made to his work at the time of publication&rdquo;). This labor must have <lb/>absorbed all the energy and attention to Caverni, who was evidently spurred on <lb/>and excited by the many disappointments of which we have spoken. </foreign></s>

<s><foreign lang="en">In a <lb/>certain sense, it must also have concerned and galvanized all the little com&shy;<lb/>munity of which he was the spiritual leader. </foreign></s>

<s><foreign lang="en">I recently found a local inhabitant, <lb/>one Egidio Longhi of considerable age but most lucid memory, who told me, <lb/>&ldquo;It was my grandfather Giovanni who took the manuscripts to the printer, to <lb/>Civelli.&rdquo; And he must have made many trips and carried many papers if we <lb/>consider that in fewer than ten years a little under 3,500 large quarto pages, <lb/>dense with characters, were printed! </foreign></s></p><p type="main">

<s><foreign lang="en">Caverni was a healthy man. </foreign></s>

<s><foreign lang="en">He led the most wholesome and methodical life <lb/>one can imagine, with a walk every day and an excursion, always the same one, <lb/>in the surrounding countryside every week. </foreign></s>

<s><foreign lang="en">But that intense and hurried work, <lb/>that prize they did not want to give him if he did not publish everything first, <lb/>those comments and reviews of which only the favorable ones failed to affect <lb/>him, must have undermined his physical resistance. </foreign></s>

<s><foreign lang="en">It seems that in the winter <lb/>between 1899 and 1900 he neglected a case of nephritis; toward the end of <lb/>January he was found unconscious by the man who served as his housekeeper. </foreign></s>

<s><foreign lang="en"><lb/>He died a few days later, without either his relatives or a doctor having been <lb/>called. </foreign></s>

<s><foreign lang="en">His death was reported by Procacci in that <emph type="italics"/>Rassegna Nazionale<emph.end type="italics"/> with <lb/>which Caverni had so actively collaborated. <lb/><lb/>I quote from his announcement, <lb/>omitting a few adjectives: &ldquo;He died on the 30th last at 4:25 in the morning at <lb/>the age of 63.... The florid health he enjoyed and his robust physical con&shy;<lb/>stitution had led us to hope that ... he would reach a very advanced age.... <lb/>Although he dedicated all his time to study, he did not neglect his duties as <lb/>parish priest, to which he attended with untiring zeal and intelligent love. </foreign></s>

<s><foreign lang="en">Not <pb xlink:href="020/01/018.jpg" pagenum="xix"/>only his own parishioners, but vacationers from the neighboring countryside as <lb/>well came willingly to hear his Sunday lectures on the Gospels.... Both the <lb/>clergy and the population of the town of Bagno a Ripoli, among whom he lived <lb/>for so long and who could therefore judge his great virtues at close hand, <lb/>flocked in great numbers to accompany him to his grave and a colleague, Prior <lb/>Cini,... praised his knowledge, virtue and modesty. </foreign></s>

<s><foreign lang="en">Two musical societies <lb/>rendered the funeral procession more solemn.&rdquo; And the long and steep walk up <lb/>to the cemetery which dominates the river from the other flank of the valley <lb/>must have reminded that little crowd, all village and country folk, of his <lb/>countless methodical hikes over the same splendid hills. </foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>8. ODYSSEY OF THE MANUSCRIPTS<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">In his will which he had drawn up just three months earlier, besides giving <lb/>instructions for his funeral&mdash;significant for the simplicity and the poetry that <lb/>inspires them&mdash;he left his books and manuscripts to his older brother, Giuseppe, <lb/>with the obligation to transmit them to his eldest son, Egisto, who was in turn <lb/>to leave them to his firstborn and so on, as has been done. </foreign></s>

<s><foreign lang="en">Egisto Caverni, the <lb/>favorite nephew with whom his uncle often met in Florence and who had <lb/>taken up the trade of carpenter, went to get them at the parsonage of San <lb/>Bartolomeo in Quarate with one of those two-wheeled carts which once carried <lb/>bricks to the building yards of Florence, and in 1906 Filippo Orlando could <lb/>write that &ldquo;the books, the manuscripts of Caverni, some unpublished and <lb/>important, are still kept in an orderly collection with pious veneration by his <lb/>family in S. </foreign></s>

<s><foreign lang="en">Quirico di Montelupo where he was born; his nephew, Egisto <lb/>Caverni, full of intelligence and reverent affection although he lives by the <lb/>work of his hands, keeps them all in order in the best room of the house....&rdquo; <lb/>This old friend expressed the hope that these papers would be passed on to <lb/>the Biblioteca Nazionale of Florence. <lb/><lb/>Twelve years later, Father Giovanni <lb/>Giovannozzi, printing an unpublished chapter of the <emph type="italics"/>Storia,<emph.end type="italics"/> spoke again of that <lb/>precious material: &ldquo;In my studies I have more than once consulted the original <lb/>manuscript possessed by the nephews and heirs of Abbot Caverni and made <lb/>extracts of it. </foreign></s>

<s><foreign lang="en">And now, in agreement with the owners, I am happy to offer <lb/>students of the history of science the chapter concerning the doctrine and <lb/>works of the ex-Scolopian Famiano Michelini....&rdquo; <lb/><lb/>Since then, that is, for <lb/>about half a century, I do not think there was any further news of those <lb/>manuscripts, nor was there any trace of them in the Florentine archives. <pb xlink:href="020/01/019.jpg" pagenum="xx"/>At Montelupo I heard that the Caverni had moved away some time ago; <lb/>fortunately, a relative was able to tell me they now live in Prato. </foreign></s>

<s><foreign lang="en">Thus I <lb/>was able to trace Egisto's eldest son, Lamberto, and at his home I was able <lb/>to look the manuscripts over and hear of their vicissitudes. </foreign></s>

<s><foreign lang="en">Lamberto Caverni <lb/>does not remember Giovannozzi's visits; during those years he was away in <lb/>the war. </foreign></s>

<s><foreign lang="en">He does remember that his father's large family (Egisto raised ten <lb/>children) was always ready to receive and assist anyone who declared he <lb/>wanted to study or copy those papers. </foreign></s>

<s><foreign lang="en">But not everyone behaved as loyally <lb/>as Giovannozzi: someone even published some unprinted works in his own <lb/>name, not without taking all the postage stamps off the correspondence! In <lb/>the meantime, by making many sacrifices, Egisto Caverni was able to set up a <lb/>saw mill with a shop for making packing cases; he rented a place in the street <lb/>named today for Raffaello Caverni in a zone separated from the capital, <lb/>Montelupo, only by the Pesa river which flows into the Arno there. </foreign></s>

<s><foreign lang="en">After a <lb/>few years, not far from there, he began to build himself a new house on the <lb/>avenue that leads to the Villa Ambrogiana. </foreign></s>

<s><foreign lang="en">The manuscripts, naturally, <lb/>followed the family as it moved and were always allotted the most decorous <lb/>space possible. </foreign></s>

<s><foreign lang="en">Once the war was over and the two sons who had taken part in <lb/>it returned home, the little packing case factory began to prosper. </foreign></s>

<s><foreign lang="en">But on the <lb/>day of Epiphany in 1920, after a period of heavy rains, the rivers swelled <lb/>beyond measure and the Pesa overflowed with incredible violence. </foreign></s>

<s><foreign lang="en">The <lb/>manuscripts were on the ground floor in the &ldquo;office&rdquo; and were transferred to <lb/>the upper floor just in time. </foreign></s>

<s><foreign lang="en">The fury of the waters destroyed the stone walls <lb/>around the property and swept away all the lumber stored there; the house <lb/>itself seemed about to collapse. </foreign></s>

<s><foreign lang="en">During the months following the flood every <lb/>attempt was made to recover from that ruin, but a year later another flood <lb/>similar to the first put a definite end to the artisan activity of that large family, <lb/>reducing it, literally, to desperation. </foreign></s>

<s><foreign lang="en">It was then they thought of moving to <lb/>Prato because their best clients were there and, perhaps, to avoid the risk of <lb/>another useless effort. </foreign></s>

<s><foreign lang="en">But they needed at last 20,000 lire to set themselves up <lb/>in business again, capital which a relative was ready to offer, against, however, <lb/>ample guarantees. </foreign></s>

<s><foreign lang="en">For these he asked for Raffaello Caverni's manuscripts <lb/>which Egisto and his ten children had shown they cared for more than anything <lb/>else! In a few years of hard work in the favorable zone of Prato, the Caverni put <lb/>their old business back on its feet. </foreign></s>

<s><foreign lang="en">But Lamberto remembers that his father, by <lb/>then old and infirm, could find no peace until he could go to Montelupo to repay <lb/>that debt and regain the manuscripts. </foreign></s>

<s><foreign lang="en">Naturally, their troubles were not over. </foreign></s>

<s><foreign lang="en"><lb/>During the Second World War, in the air raid of January 17, 1943, the <lb/>Caverni house and factory were once again destroyed, but the manuscripts had <lb/>already been opportunely evacuated to a safe place under the church of nearby <lb/>Figline and could thus be returned undamaged to the family. </foreign></s>

<s><foreign lang="en">Indeed, Lamberto <lb/>Caverni, following the instructions of his great-uncle's will has already con-<pb xlink:href="020/01/020.jpg" pagenum="xxi"/>signed them to Pietro, his firstborn, who keeps them at the disposition of those <lb/>scholars of the history of science who at last want to remember their existence. </foreign></s></p><p type="main">

<s><foreign lang="en"><emph type="center"/>9. CONCLUSION<emph.end type="center"/></foreign></s></p><p type="main">

<s><foreign lang="en">To the long oblivion of the manuscripts there corresponds a silence almost as <lb/>continuous in the last half century regarding the volumes of the <emph type="italics"/>Storia.<emph.end type="italics"/> And <lb/>if some sporadic attention has been given them, this has been abroad rather than <lb/>in Italy. </foreign></s>

<s><foreign lang="en">Here, in fact, one of the last times someone concerned himself with the <lb/>work, naturally in deprecation of it, was at the tenth meeting of the <emph type="italics"/>Societ&agrave; <lb/>italiana per il progresso delle scienze<emph.end type="italics"/> (Italian society for the progress of science) <lb/>held in Pisa in April 1919. In conclusion of two &ldquo;laborious and crowded <lb/>sessions&rdquo; of the history of science section, an order of the day was approved <lb/>in which, besides voting to reprint the national edition of Galileo's works, the <lb/>hope was expressed that &ldquo;in view of renewed anti-Galilean attempts,&rdquo; prime <lb/>responsibility for which was imputed to the scholar of Montelupo,&rdquo; a critical <lb/>review of Caverni's <emph type="italics"/>Storia<emph.end type="italics"/> would be made, to bring to light the intentions and <lb/>the means employed by the author in judging Galileo's work.&rdquo; <lb/><lb/>A series of <lb/>articles in the &ldquo;Archivio&rdquo; follows this proposal, among which there is also one <lb/>which Mieli accepted in favor of Caverni, written by Giovannozzi. </foreign></s>

<s><foreign lang="en">The other <lb/>writers were Favaro, with the article already cited regarding the matter of the <lb/>phases of Venus, the only page of Caverni which should, in fact, be censured, <lb/>and the physicist Carlo Del Lungo who had raised the question at the meeting <lb/>and who gave Mieli two rather ample essays. <lb/><lb/>There is nothing new in them. </foreign></s>

<s><foreign lang="en"><lb/>The most valid criticism concerns the interpretation of Santorio's <emph type="italics"/>Cotyla,<emph.end type="italics"/> which <lb/>Caverni at first took to be a real pendulum clock when it is actually a small <lb/>pendulum whose length can be regulated and which is made to oscillate by <lb/>hand, like Santorio's similar <emph type="italics"/>pulsilogio.<emph.end type="italics"/> Schiaparelli had already noticed this <lb/>oversight almost twenty years before, and Caverni himself in the fourth volume <lb/>of his <emph type="italics"/>Storia<emph.end type="italics"/> had made ample amends for this error. </foreign></s>

<s><foreign lang="en">Del Lungo's insistence is <lb/>therefore useless; moreover, his article (the nemesis of chance) is illustrated by <lb/>a drawing of the <emph type="italics"/>Cotyla<emph.end type="italics"/> reproduced upside down! With this the &ldquo;critical re&shy;<lb/>view&rdquo; voted at Pisa by the Italian scientists in congress ended with the classical <lb/>results of the mountain's travail. </foreign></s></p><p type="main">

<s><foreign lang="en">Abroad, as we have said, interest in the <emph type="italics"/>Storia del metodo sperimentale in <lb/>Italia<emph.end type="italics"/> registers further significant episodes. </foreign></s>

<s><foreign lang="en">In 1952 George Sarton, in his book <lb/><emph type="italics"/>A Guide to the History of Science,<emph.end type="italics"/> puts Caverni's <emph type="italics"/>Storia<emph.end type="italics"/> in the first place for <pb xlink:href="020/01/021.jpg" pagenum="xxii"/>Italy, followed by only two other titles (<emph type="italics"/>Da Leonardo a Marconi<emph.end type="italics"/> by Savorgnan <lb/>di Brazz&agrave; and <emph type="italics"/>Un secolo di progresso scientifico italiano<emph.end type="italics"/> in 7 volumes, edited by <lb/>L. Silla). Many years before, Leonardo Olschki, <lb/><lb/>in his history of scientific <lb/>works in the vulgar tongue, also left unfinished, cites Caverni repeatedly <lb/><lb/>and <lb/>it is obvious that he thinks highly of the man's ample exegesis of the sources of <lb/>common interest. </foreign></s>

<s><foreign lang="en">Even this new reprint is an initiative of American origin. </foreign></s>

<s><foreign lang="en"><lb/>And it was Harry Woolf, former editor of <emph type="italics"/>Isis,<emph.end type="italics"/> who invited me to write this <lb/>introductory note, for which I am truly grateful. </foreign></s>

<s><foreign lang="en">It is still not a study of this <lb/>work, but, I hope, a premise and a
stimulus to finally beginning one. </foreign></s><!-- end english --></p><pb xlink:href="020/01/022.jpg"/><pb xlink:href="020/01/023.jpg"/><pb xlink:href="020/01/024.jpg"/><p type="main">

<s><emph type="center"/>RELAZIONE<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>DELLA<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>GIUNTA DEL R. ISTITUTO VENETO<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>DEPUTATA ALL'ESAME<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>DEI LAVORI PRESENTATI AL CONCORSO DELLA FONDAZIONE TOMASONI<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>SUL TEMA:<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/><emph type="bold"/>STORIA DEL METODO SPERIMENTALE IN ITALIA<emph.end type="bold"/><emph.end type="center"/></s></p><p type="main">

<s>Per la seconda volta &egrave; chiamato il R. </s>

<s>Istituto a pronunziare il suo <lb/>giudizio intorno ai lavori, presentati al concorso della fondazione Tomasoni <lb/>sul tema: <emph type="italics"/>&ldquo; Storia del metodo sperimentale in Italia &rdquo;,<emph.end type="italics"/> e, per agevolare <lb/>in questo caso l'adempimento di tale, che &egrave; fra le pi&ugrave; alte missioni del&shy;<lb/>l'Istituto nostro, la Commissione, deputata a fornirvi gli elementi per siffatto <lb/>giudizio, ha stimato opportuno di cominciare dall'esporvi succintamente le <lb/>varie fasi, attraverso le quali questo importante concorso &egrave; finora passato. </s></p><p type="main">

<s>Il defunto Giovanni Tomasoni, con suo testamento olografo del 4 di&shy;<lb/>cembre 1879, disponeva a favore del nostro Istituto un legato di lire cin&shy;<lb/>quemila, da darsi in premio <emph type="italics"/>&ldquo; a chi detter&agrave; meglio la storia del metodo <lb/>sperimentale in Italia &rdquo;.<emph.end type="italics"/> La medesima disposizione testamentaria recando, <lb/>che il programma di concorso fosse determinato dall'Istituto, questo for&shy;<lb/>mulava il tema nei seguenti termini: <emph type="italics"/>&ldquo; Esporre le vicende ed i progressi <lb/>del metodo sperimentale in Italia, principalmente studiato nelle sue <lb/>applicazioni alle scienze fisiche, con particolare riguardo a tutto ci&ograve; <lb/>che esso offre di notevole nei quattro secoli fra il principio del de&shy;<lb/>cimoquinto e la fine del decimottavo, comprendendo la scopcrta della <lb/>pila voltaica. </s>

<s>A compiere la trattazione del quesito baster&agrave; aggiungere <lb/>un ragguaglio storico, ristretto all'Italia, sul progressivo e rapido svol&shy;<lb/>gimento, non solo delle scienze fisiche, ma benanco delle economiche e <lb/>sociali per opera del metodo sperimentale &rdquo;.<emph.end type="italics"/></s></p><p type="main">

<s>Allo scopo di meglio chiarire i suoi intendimenti, la Commissione, alla <lb/>quale era stato affidato l'incarico di formulare il tema, aggiungeva che, <lb/>secondo il suo parere, opportuna introduzione al corpo principale dello <lb/>scritto avrebbe dovuto essere un cenno storico riassuntivo di quant&ograve; si oper&ograve; <lb/>nell'antichit&agrave; in Italia con indirizzo sperimentale, studiando le cause, per <lb/>le quali quelle sane idee rimasero affogate sotto la marea dei peripatetici <pb xlink:href="020/01/025.jpg" pagenum="6"/>sedicenti seguaci di Aristotele; e che infine opportuna conchiusione del la&shy;<lb/>voro avrebbe dovuto essere lo studio della influenza esercitata dalla scuola <lb/>Galileiana, mettendo in luce se e qual parte abbiano avuta gli stranieri nella <lb/>definitiva adozione del metodo sperimentale. </s>

<s>Queste ultime avvertenze, in&shy;<lb/>tese, pi&ugrave; che ad altro, a render maggiormente chiaro il concetto della Com&shy;<lb/>missione presso l'Istituto, che doveva giudicarne l'elaborato, vennero, e forse <lb/>con non molta opportunit&agrave;, aggiunte al programma di concorso. </s></p><p type="main">

<s>Alla scadenza del concorso fissata per il febbraio dell'anno 1885 fu&shy;<lb/>rono presentati due lavori, uno dei quali contraddistinto dal motto: <emph type="italics"/>&ldquo; Va&shy;<lb/>gliami'l lungo studio e'l grande amore &rdquo;;<emph.end type="italics"/> e l'altro colla divisa del: <emph type="italics"/>&ldquo; Pro&shy;<lb/>vando e riprovando &rdquo;.<emph.end type="italics"/> Accogliendo le conchiusioni della Commissione, <lb/>l'Istituto non conferi il premio ad alcuno di essi, e, dovendo, in obbedienza <lb/>alle tavole di fondazione, essere il tema medesimo posto a concorso, fintan&shy;<lb/>toch&egrave; se ne abbia una soluzione che del premio sia degna, la Commissione <lb/>stessa sottopose all'Istituto alcune considerazioni sulla opportunit&agrave; di mo&shy;<lb/>dificare alquanto i termini e le condizioni del primitivo enunciato di esso. </s>

<s><lb/>Riflettendo alla vastit&agrave; grandissima del tema ed alle difflcolt&agrave; gravissime che <lb/>ne presenta una lodevole soluzione, la Commissione era venuta unanime <lb/>nella deliberazione di chiedere all'Istituto che il concorso venisse riaperto, <lb/>limitandolo soltanto alle scienze fisiche, naturali e biologiche, escludendo <lb/>affatto le scienze morali, od almeno lasciandone la trattazione all'arbitrio <lb/>dei concorrenti, Osservava la Commissione che, anche cosi limitato, il tema <lb/>nulla perdeva della sua grandissima importanza relativa, ed esigeva pur tut&shy;<lb/>tavia, cos&igrave; gran somma di lavoro, da non riuscire ad esso sproporzionato il <lb/>cospicuo premio largito dalla generosit&agrave; del testatore. </s>

<s>Che anzi essa Com&shy;<lb/>missione si era mostrata cos&igrave; profondamente penetrata dell'altezza del tema <lb/>e delle difficolt&agrave; che esso offre, da non esitare ad esprimere il desiderio <lb/>che venisse apertamente dichiarato come <emph type="italics"/>anche una monografia di grande <lb/>valore, la quale contemplasse soltanto l'epoca pi&ugrave; saliente nella storia <lb/>del metodo sperimentale, quale sarebbe quella rappresentata da uno stu&shy;<lb/>dio profondo e completo intorno a Galileo ed alla sua scuola, sarebbe <lb/>tornata bene accetta all'Istituto, ed avrebbe potuto essere giudicata me&shy;<lb/>ritevole di premio.<emph.end type="italics"/></s></p><p type="main">

<s>L'Istituto accolse la prima proposta della Commissione; ma rispetto alla <lb/>seconda non stim&ograve; opportuno di limitare il tema da porsi al concorso, e, <lb/>riservandosi piena libert&agrave; di azione quanto ai lavori che fossero per essere <lb/>prodotti, e riconoscendo che anche quella pi&ugrave; ristretta monografia, quando <lb/>fosse stata di eccezionale valore, avrebbo dovuto esser presa in considera&shy;<lb/>zione, prefer&igrave; di mantenere al tema la sua vastit&agrave;, chiarendo anzi che, oltre <lb/>alle scienze fisiche, avrebbe dovuto essere studiata la storia del metodo spe&shy;<lb/>rimentale anco rispetto alle naturali e biologiche. </s>

<s>In seguito a ci&ograve;, mante&shy;<lb/>nuta la dizione conforme alla volont&agrave; del testatore, cio&egrave;, dichiarato che il <lb/>premio sarebbe stato conferito <emph type="italics"/>&ldquo; a chi detter&agrave; meglio la storia del metodo <lb/>sperimentale in Italia &rdquo;,<emph.end type="italics"/> volle specificato il tema nei termini seguenti: <pb xlink:href="020/01/026.jpg" pagenum="7"/><emph type="italics"/>&ldquo; Esporre le origini, le vicende ed i progressi del metodo sperimentale in <lb/>Italia, studiato nelle suc applicazioni alle scienze fisiche, naturali e bio&shy;<lb/>logiche, con particolare riguardo a tutto ci&ograve; ch'esso offre di notevole nei <lb/>quattro secoli fra il principio del decimoquinto e la fine del decimottavo, <lb/>compresa la scoperta della pila voltaica &rdquo;,<emph.end type="italics"/> aggiuntavi poi l'avvertenza che <lb/>era <emph type="italics"/>&ldquo; lasciato all'arbitrio dei concorrenti il trattare, con quell'estensione <lb/>che crederanno, la storia del metodo sperimentale applicato alle scienze <lb/>morali &rdquo;.<emph.end type="italics"/></s></p><p type="main">

<s>Due furono i lavori presentati alla scadenza del concorso, fissata al 31 <lb/>marzo 1889. </s></p><p type="main">

<s><emph type="italics"/>Spes premii minuit vim laboris<emph.end type="italics"/> &egrave; il motto sotto il quale si ripresenta <lb/>l'autore, che, nel primo concorso, s'era coperto della celebre divisa: <emph type="italics"/>&ldquo; Pro&shy;<lb/>vando e riprovando &rdquo;.<emph.end type="italics"/> &Egrave; d'uopo convenire che il lavoro rifatto presenta <lb/>minori mende del primo; ma purtroppo queste sono tuttavia in cos&igrave; gran <lb/>numero e talmente gravi, da togliere ad esso qualsiasi considerazione. </s>

<s>L'au&shy;<lb/>tore si &egrave; per verit&agrave; sforzato di esaurire tutto intero il programma del con&shy;<lb/>corso; ma il modo, col quale il lavoro &egrave; anche questa volta condotto, di&shy;<lb/>mostra, in maniera troppo evidente, che all'autore di esso fanno soverchio <lb/>difetto estensione e profondit&agrave; di coltura per potersi accingere ad un tanto <lb/>cimento. </s></p><p type="main">

<s>Ed anzitutto ammetteremo che l'esemplare, il quale ne abbiamo sot&shy;<lb/>t'occhio, sia l'opera di un amanuense, e che all'autore sia mancato anche <lb/>il tempo di rileggerlo, perch&egrave;, quando cos&igrave; non fosse, alcuni grossolani er&shy;<lb/>rori ci avrebbero consigliato a chiudere senz'altro il volume, per non spre&shy;<lb/>care il tempo, che pure abbiamo dovuto spendervi intorno per diligente&shy;<lb/>mente esaminarlo. </s>

<s>N&egrave; questo avremmo notato se certi indizi, di grande <lb/>significato per un attento osservatore, non ci avessero dimostrato che, se <lb/>non tutti, parecchi almeno di quegli errori appariscono dovuti a quel ca&shy;<lb/>pitale difetto che pur ora abbiamo avvertito. </s>

<s>Il quale si manifesta princi&shy;<lb/>mente nella scelta delle fonti, che non sono mai le prime, mentre quelle <lb/>di seconda o di terza mano, alle quali attinse l'autore, non sono le migliori, <lb/>imperocch&egrave; la massima parte delle citazioni (e potremmo quasi dire tutte) <lb/>si riferiscono a lavori di compilazione, il pi&ugrave; delle volte dovuti a scrittori <lb/>che non passano per i pi&ugrave; scrupolosi (quando non sieno di autori troppo <lb/>noti per la loro parzialit&agrave;), e che, per l'epoca alla quale appartengono, non <lb/>poterono approffittare dei pi&ugrave; recenti studi condotti con quelle norme, dalle <lb/>quali la critica, degna di tal nome, non vuole che si prescinda. </s></p><p type="main">

<s>Anche la cronologia, la cui esattezza deve pur tenersi per tanta parte <lb/>in un lavoro destinato a porgere un quadro delle origini e dello sviluppo <lb/>del metodo sperimentale, lascia moltissimo a desiderare; n&egrave; mancano esempi <lb/>di fatti i quali vengono ripetuti, attribuendoli ad epoche fra loro diverse. </s></p><p type="main">

<s>Di queste mende di varia natura, ma indistintamente assai gravi, si <pb xlink:href="020/01/027.jpg" pagenum="8"/>risente il lavoro in tutte le sue parti, le quali non sono nemmeno ben pro&shy;<lb/>porzionate fra loro, poich&egrave; quasi due terzi del cammino vengono percorsi <lb/>prima di incontrare l'opera Galileiana; cosicch&egrave; si comprende quanto ina&shy;<lb/>deguatamente rimanga trattata la scuola dell'immortale filosofo, della quale <lb/>l'autore non sospetta nemmeno i copiosi ed importanti materiali che avrebbe <lb/>potuto fornire al suo lavoro. </s></p><p type="main">

<s>Quando finalmente avremo ancora soggiunto, che, in generale, l'autore <lb/>si tiene sempre ad affermare senza porgere dimostrazioni, che le questioni <lb/>pi&ugrave; gravi sono trattate nel modo pi&ugrave; superficiale che immaginar si possa, <lb/>e che anche i fatti pi&ugrave; salienti, oltre ad essere assai scarsamente lumeg&shy;<lb/>giati, vengono esposti, senza curare di porne in evidenza la parte essenziale, <lb/>cio&egrave; il nesso colla creazione, colla adozione e col progresso del metodo spe&shy;<lb/>rimentale, del quale deve scriversi la storia, ci pare che non vi sia bisogno <lb/>di entrare in pi&ugrave; minute analisi, per giustificare la couchiusione che in <lb/>nessun modo pu&ograve; questo lavoro aspirare al conferimento del premio. </s></p><p type="main">

<s>Un indirizzo completamente diverso, e quasi diremmo opposto, ha se&shy;<lb/>guito l'autore dell'altro lavoro, di proporzioni veramente colossali (sono 3264 <lb/>pagine di grandissimo formato tutte scritte per intero), il quale vi ha posta <lb/>in fronte la significante terzina dantesca: </s></p><p type="main">

<s><emph type="center"/>&ldquo; Da questa instanzia pu&ograve; deliberarti <lb/>Esperienza, se giammai la provi <lb/>Ch'esser suol fonte a'rivi di vostr'arti &rdquo;.<emph.end type="center"/></s></p><p type="main">

<s>S'apre il lavoro con un magistrale discorso preliminare, nel quale, con <lb/>una robusta sintesi, tracciato un quadro di quella, che volentieri chiame&shy;<lb/>remmo preistoria del metodo sperimentale, se ne mostrano i fondamenti, <lb/>porgendo in pari tempo il disegno di tutta l'opera. </s></p><p type="main">

<s>E prendendo le mosse dal &ldquo; primo acquisto delle cognizioni &rdquo;, il nostro <lb/>autore ci addita in Platone ed in Aristotele i primi ed i principali che in&shy;<lb/>vestigassero le leggi, secondo le quali si acquistano dall'intelletto umano e <lb/>si svolgono nel pensiero le cognizioni; e, mostrato il diverso indirizzo da <lb/>loro segu&igrave;to e la inutilit&agrave; del metodo sperimentale tanto per l'uno quanto <lb/>per l'altro, chiarisce tuttavia come, mentre la Stagirita credeva di potere <lb/>supplire in ogni modo, colla ragione, all'esperienza, il fondatore dell'Acca&shy;<lb/>demia venisse efficacemente avviando gli ingegni all'arte dello sperimentare, <lb/>preparandoveli colla geometria. </s></p><p type="main">

<s>Di Grecia mostra diffondersi le dottrine dei due maestri in Italia, con <lb/>varia vicenda, e con Tommaso d'Aquino istituirsi la scuola peripatetica, che <lb/>soggiog&ograve; gli ingegni, insino a tutto il secolo XVI. </s>

<s>Nessun vantaggio egli <lb/>riconosce alla scienza sperimentale da parte della schiera dei cosidetti ra&shy;<lb/>zionalisti, alla quale appartennero Francesco Patrizio, Bernardino Telesio, <lb/>Giordano Bruno, Tommaso Campanella, poich&egrave;, se pur insorsero a scuotere <pb xlink:href="020/01/028.jpg" pagenum="9"/>il lungo giogo, non fecero altro che sostituir&egrave; alla ragione ed alla autorit&agrave; <lb/>di Aristotele, la ragione e l'autorit&agrave; loro propria. </s></p><p type="main">

<s>Primi a promuovere quella scienza egli ci addita coloro, che, indipen&shy;<lb/>dentemente dagli insegnamenti ricevuti nella scuola, rivolsero gli occhi a <lb/>contemplar la natura, nei var&igrave; e molteplici esercizi dell'arte. </s>

<s>Cos&igrave;, dall'arte <lb/>del verso, ebbe origine la fisica sperimentale dell'Alighieri; dell'arte navi&shy;<lb/>gatoria, la meteorologia e la geografia fisica di Cristoforo Colombo e l'astro&shy;<lb/>nomia di Amerigo Vespucci; come, dall'arte del disegno, scatur&igrave; quella larga <lb/>vena di scienza naturale, che non si finirebbe di ammirar mai negli scritti <lb/>di Leonardo da Vinci. </s></p><p type="main">

<s>Non tralascia tuttavia il nostro autore di toccare di alcuni, i quali in <lb/>que'secoli, essendo pure imbevuti dei princip&igrave; peripatetici, ebbero qualche <lb/>sentore ed esercizio d'arte sperimentale: primi fra questi il Fracastoro, il <lb/>Cardano ed il Cesalpino; ma i frutti di scienza naturale, che trovansi di&shy;<lb/>spersi qu&agrave; e l&agrave; per i loro volumi, egli li riconosce non tanto dalle scuole, <lb/>quanto invece dal pratico esercizio dell'arte medica. </s></p><p type="main">

<s>E che pi&ugrave; efficacemente conferisse ai progressi del metodo sperimen&shy;<lb/>tale la vita pratica e la conoscenza del mondo che non la scuola, ne trova <lb/>il nostro Autore la prova suprema nel Sarpi, del quale &egrave; caldissimo ed <lb/>anzi, a parer nostro, esagerato ammiratore. </s>

<s>Questo egli dipinge, circon&shy;<lb/>dato dal Ghetaldi, dal Porta, dal Sagredo, dall'Antonini e dal De Dominis, <lb/>attendere ad osservazioni, a discussioni, ad esperienze: in tal nucleo di stu&shy;<lb/>diosi egli ravvisa i veri precursori e gli efficaci promotori del metodo spe&shy;<lb/>rimentale, il quale aveva avuto gi&agrave; da un secolo una assai efficace promo&shy;<lb/>zione in Toscana dall'Accademia platonica instituita nella Corte dei Medici. </s>

<s><lb/>Allora, ad abbattare il Peripato, che conformava alla ragione e al senso le <lb/>leggi della natura, il nostro autore ci mostra il sorgere dell'Accademia, la <lb/>quale, insegnando a leggere in quel libro, che ci si squaderna innanzi agli <lb/>occhi, e che &egrave; scritto con caratteri geometrici, invit&ograve; gli studiosi a svolgere <lb/>insieme coi volumi di Platone, quelli altres&igrave; di due dei pi&ugrave; eccellenti, che <lb/>fiorissero in quella scuola, Archimede ed Erone. </s></p><p type="main">

<s>Cosi, dal quadro, del quale andiamo riproducendo le linee massime, <lb/>appariscono disposte le cose per modo che la instituzione dell'arte speri&shy;<lb/>mentale dovesse occorrere alla Toscana; cosi avvenne di fat<emph type="italics"/>t<emph.end type="italics"/>o, per il magi&shy;<lb/>stero di Galileo Galilei, a cui i posteri, plaudendo e gratulando, attribuirono, <lb/>del pari che al maestro, dal quale prese la ispirazione, il nome di divino. </s>

<s><lb/>Egli, fuggendo il Peripato, da Platone succhi&ograve; i primi e veri princip&igrave; della <lb/>scienza del moto; da Archimede, oltre alla scienza del moto; e dell'equili&shy;<lb/>brio de'corpi solidi e liquidi, ebbe le prime rivelazioni del sistema del mondo, <lb/>e da Erone apprese i primi saggi di fisica sperimentale. </s></p><p type="main">

<s>Se Galileo fosse rimasto solo, come tanti suoi predecessori, non avrebbe <lb/>avuto certamente quella grande efficacia, che egli ebbe, nel promuovere le <lb/>scienze sperimentali. </s>

<s>Uno dei pi&ugrave; gran meriti, che se gli deve attribuire, &egrave; <lb/>dunque quello d'avere formato una scuola, in cui s'ebbero i primi seggi il <pb xlink:href="020/01/029.jpg" pagenum="10"/>Castelli, il Torricelli, il Cavalieri. </s>

<s>E qui il nostro autore lascia a divedere <lb/>che questo formarsi e svolgersi della scuola Galileiana costituir&agrave; il principale <lb/>nucleo del suo lavoro. </s></p><p type="main">

<s>Morti, con Galileo, il Castelli ed il Cavalieri, rimase il Torricelli a rap&shy;<lb/>presentare quella scuola dentro a quel recinto, dov'ebbe la sua culla, cio&egrave; <lb/>la corte medicea. </s>

<s>Nella celebre esperienza dell'argento vivo, che il Mersenne <lb/>attinse in Roma dalla bocca di Michelangelo Ricci, e che egli poi, il Mer&shy;<lb/>senne, comunic&ograve; al Pascal, ritornato in Francia, ci addita la scintilla, che <lb/>second&ograve; una gran fiamma, a cui si scaldarono e illuminarono tutti gli in&shy;<lb/>gegni di Europa. </s>

<s>Nel Torricelli, che, alla corte del Granduca Ferdinando II <lb/>fabbricava telescopi, e inventava altri strumenti, riconosce egli l'autore del <lb/>pi&ugrave; grande incremento che ricevesse mai in quel tempo l'istituzione Gali&shy;<lb/>leiana. </s>

<s>Ed a lui, rapito cos&igrave; presto alla scienza, ci mostra succedere il Vi&shy;<lb/>viani, il Borelli ed il Rinaldini, sui quali tre validissimi ingegni, ma sui <lb/>primi due principalmente, fondava Leopoldo de'Medici le generose speranze <lb/>di istituire un'Accademia, a cui si potesse, anco formalmente, attribuire un <lb/>tal nome. </s>

<s>Tale fu l'Accademia del Cimento, nella quale, sebbene gli scien&shy;<lb/>tifici consessi incominciassero inf&igrave;no dal 1657, non ostante, al pubblico, non <lb/>se ne comunicarono le scoperte, se non che nel 1666 in quel volume, a <lb/>cui si volle dar giustamente il titolo di <emph type="italics"/>Saggi,<emph.end type="italics"/> perch&egrave; nient'altro son vera&shy;<lb/>mente se non che saggi di quella ricca e feconda miniera d'oro, che si ri&shy;<lb/>man tuttavia nascosta e involta nella scoria dei manoscritti. </s></p><p type="main">

<s>Conveniamo con l'autore nel tenere che, fatto cardinale il Principe <lb/>Leopoldo, l'Accademia non svanisse per essersi l'institutore di essa rivolto <lb/>tutto agli studi ecclesiastici; ma nella risoluzione del Borelli di ritornarsene <lb/>in patria, nelle esercitazioni idrauliche a cui il Principe ed i privati tennero <lb/>continuamente rivolto il Viviani, nelle lontane peregrinazioni del Magalotti, <lb/>noi non ravvisiamo, come vorrebbe il nostro autore, la causa, ma bens&igrave; l'ef&shy;<lb/>fetto della cessazione della sperimentale Accademia, poich&egrave; si trova in pi&ugrave; <lb/>luoghi affermato che la morte di essa fu posta da Roma come condizione <lb/>per insignire il Principe Leopoldo della porpora cardinalizia. </s></p><p type="main">

<s>Al Borelli ed al Viviani il nostro fa seguire lo Stenone ed il Redi, i <lb/>quali p<emph type="italics"/>o<emph.end type="italics"/>rtarono di preferenza la loro attenzione sulle cose di storia natu&shy;<lb/>rale, e fa vedere come il Borelli, che aveva applicata la matematica alla fi&shy;<lb/>siologia, il Michelini, che lo stesso metodo aveva applicato all'arte medica, <lb/>e fu primo institutore della medicina sperimentale, fecondando gli ingegni <lb/>del Malpighi e del Redi, operarono s&igrave;, che, se non dentro l'Accademia del <lb/>Cimento, poco per&ograve; al di fuori, sorgessero prosperose l'Anatomia micro&shy;<lb/>scopica e la vera Storia Naturale, che vennero cosi a dar la massima esten&shy;<lb/>sione, e a render quasi compiuta la grande instituzione di Galileo. </s></p><p type="main">

<s>Tutto questo grande avvicendarsi di studi, tutte queste piramidi di luce, <lb/>che muovono da Galileo stesso, come da prima luminosa sorgente, e si ri&shy;<lb/><gap/>ettono, e si rinfrangono, e s'incolorano in tanti illustri ingegni, prende <lb/>adunque il nostro autore a trattare, pigliando le mosse dalla storia dei prin-<pb xlink:href="020/01/030.jpg" pagenum="11"/>cipali strumenti che servono all'arte sperimentale, alla quale prima parte <lb/>di storia seguono immediatamente le altre due concernenti l'applicazione <lb/>dello stesso metodo sperimentale alle scienze fisiche ed alla storia naturale. </s>

<s><lb/>A questa trattazione &egrave; dedicato il primo volume diviso in due parti; ed in <lb/>essa &egrave; lasciata indietro la storia della meccanica e della idraulica, due scienze <lb/>eminentemente italiane, e delle quali i primi e principali institutori e mae&shy;<lb/>stri, per unanime consenso, sono riconosciuti Galileo ed il Castelli; alla storia <lb/>del metodo sperimentale applicato alla scienza del moto dei gravi &egrave; dedi&shy;<lb/>cato il secondo volume; il terzo ed ultimo dei presenti alla storia del me&shy;<lb/>todo stesso applicato al moto dell'acque. </s></p><p type="main">

<s>E qui ci sia concesso ripetere le parole colle quali il nostro autore <lb/>chiude il discorso preliminare. </s></p><p type="main">

<s>&ldquo; Co'tre ponderosi volumi per&ograve;, co'quali usciamo in campo noi, che <lb/>ci sentiamo di cos&igrave; lieve armatura, non vuol farsi credere che si pretenda <lb/>essere stato trattato in tutta la sua estensione, e nella sua intensione il <lb/>s&igrave; difficile tema. </s>

<s>&Egrave; tanto vasta la superficie di questo mare, e son le acque <lb/>di lui tanto profonde, che si richiede a correrlo altra barca della nostra, <lb/>e altro nocchiero. </s>

<s>L'instituto stesso preso da noi, che &egrave; di non asserire <lb/>mai i fatti, senza produrre gli opportuni documenti, ci fa bene avvertiti <lb/>de'ritrosi e degli scogli, da cui facilmente potremmo esser rimasti aggi&shy;<lb/>rati ed offesi, perch&egrave; recando altri nuovi documenti, da noi non veduti, <lb/>si verrebbero necessariamente a r&igrave;formare certe nostre storiche conclu&shy;<lb/>sioni. </s>

<s>Ma pure, da quello stesso instituto che noi proseguiamo, ha avuto <lb/>origine il volume quarto <emph type="italics"/>(il quale non &egrave; fra i presentati al concorso),<emph.end type="italics"/><lb/>che aggiungiamo all'Opera nostra, qualunque essa si sia, come corredo &rdquo;.</s></p><p type="main">

<s>&ldquo; Questo ultimo volume infati si compila tutto di documenti, per la <lb/>massima parte inediti, che noi abbiamo scelti e ordinati da'numerosissimi <lb/>manoscritti galileiani, e da quegli altri non men numerosi appartenenti <lb/>alla medicea Accademia del Cimento ... Come gemma in corona s'aggiun&shy;<lb/>gono i documenti di scienza sperimentale, ordinatamente disposti in forma <lb/>di Trattatelli, a render conte e proficue agli Italiani le solitarie specula&shy;<lb/>zioni di Leonardo ... Da alcuni libri pi&ugrave; rari, bench&egrave; stampati, abbiamo <lb/>pure fatta diligente raccolta di documenti, che alla massima parte de'let&shy;<lb/>tori giungeran come nuovi, ond'&egrave; che, se noi non ci possiam lusingare <lb/>d'aver fatto in queste lunghe e laboriose pagine, che presentiamo, opera <lb/>n&egrave; perfetta e nemmeno sufficiente; incoriamo per&ograve; una dolce speranza <lb/>d'aver forse aperta la via, e d'aver adunati i materiali a qualche altro <lb/>Autore pi&ugrave; dotto e pi&ugrave; fortunato di noi, il quale, in modo veramente de&shy;<lb/>gno della sua Nazione, torni a scriver la Storia del Metodo sperimentale <lb/>in Italia &rdquo;.</s></p><p type="main">

<s>Ed ora, dovremo noi con una diligente analsi seguire l'autore passo a <lb/>passo nello svolgimento del suo disegno? </s>

<s>&Egrave; facile il vedere che un simile <lb/>lavoro di analisi ci condurrebbe poco meno che ad aggiungere un nuovo <lb/>volume alla storia ch'egli ha scritta, laonde stimiamo meglio consentaneo <pb xlink:href="020/01/031.jpg" pagenum="12"/>all'ufficio nostro, ed insieme meglio appropriato allo scopo, il tentare un <lb/>giudizio sintetico, almeno per ci&ograve; che concerne la prima parte, dal quale <lb/>risultino in evidenza i criteri generali ch'egli ha segu&igrave;ti nello svolgimento <lb/>dell'arduo tema; dal qual giudizio apparir&agrave; che, se molto abbiamo fortuna&shy;<lb/>tamente da lodare, questo poderoso lavoro non apparve tuttavia agli occhi <lb/>nostri affatto scevro da mende, le quali abbiamo reputato nostro dovere di <lb/>non passare sotto silenzio. </s></p><p type="main">

<s>E quanto alle fonti, diciamo subito che l'Autore, pur avendo pienissima <lb/>conoscenza delle italiane edite e inedite, di queste anzi tale e tanta da non <lb/>potersi desiderare maggiore, pecca alquanto di difetto nella cognizione delle <lb/>straniere, e nei giudizi intorno ad esse formulate; e questo carattere si ri&shy;<lb/>specchia in tutto il lavoro, ed &egrave; causa talvolta di giudizi non scrupolosa&shy;<lb/>mente esatti, e tal'altra di lacune, le quali tuttavia a lui, meglio che ad <lb/>ogni altro, riuscir&agrave; agevole il colmare. </s></p><p type="main">

<s>Meno lieve ci apparve invece l'altra menda, che deriva da un troppo <lb/>facile invaghirsi della novit&agrave; delle conchiusioni, la quale, sia pur detto con <lb/>tutta la deferenza, che si merita uno studioso di tanta levatura, quanta ne <lb/>dimostra il nostro Autore, lo induce talvolta ad una interpretazione dei do&shy;<lb/>cumenti, la quale a noi non parve sempre scrupolosamente conforme al ri&shy;<lb/>gore storico. </s>

<s>E poich&egrave; quesa imputazione non pu&ograve; mantenersi campata in <lb/>aria; ma &egrave; pur mestieri fornirne una qualche giustificazione, &egrave; d'uopo che <lb/>noi entriamo in alcuni particolari. </s></p><p type="main">

<s>L'Autore si manifesta senza reticenze ammiratore profondo di Galileo <lb/>(e chi mai non lo sarebbe?); ma egli, forse posto in sull'avviso dall'ingiusto <lb/>giudizio di chi volle esaltare Galileo con pregiudizio di tutti i contemporanei, <lb/>e non consentendo in esso, pare quasi sempre in guardia contro conchiu&shy;<lb/>sioni che al sommo filosofo riescano soverchiamente favorevoli, ed il <emph type="italics"/>ratio&shy;<lb/>nabile obseqium,<emph.end type="italics"/> che lo storico deve prefiggersi come massima indeclina&shy;<lb/>bile, &egrave; da lui spinto, ci sia lecito il dirlo, ad un eccesso che noi reputiamo <lb/>ingiustifistificato. </s></p><p type="main">

<s>Noi non consentiamo col nostro autore nella incondizionata ammira&shy;<lb/>zione per Fra Paolo Sarpi scienziato; ma quand'anche dividessimo tutto <lb/>intero il suo entusiamo, non sapremmo mai indurci, come egli vorrebbe, a <lb/>dividere fra Galileo ed il Sarpi il merito delle scoperte annunziate al mondo <lb/>dal <emph type="italics"/>Sidereus Nuncius.<emph.end type="italics"/> I giudizi del Borelli sulle cose galileiane, inspirati <lb/>in gran parte dal desiderio di far dispetto all'odiato Viviani, da lui accettati <lb/>troppo facilmente, lo inducono a defraudare Galileo della parte che gli spetta <lb/>nella invenzione del termometro. </s>

<s>Arrischiato poi, ed in nessun modo giu&shy;<lb/>stificato dagli adotti documenti, e nemmeno dalle sue stesse conchiusioni, <lb/>non esitiamo ad affermare il tentativo di spogliare Galileo del merito, che <lb/>incontrastabilmente gli spetta d'aver scoperta la natura della curva descritta <lb/>dai proietti. </s>

<s>E questo noi notiamo colla piena certezza che l'autore, richia&shy;<lb/>mato a ponderar meglio questi argomenti, riformer&agrave; i suoi giudizi. </s></p><p type="main">

<s>Imperocch&egrave;, se a lui, che, forse per il primo, con intelletto d'amore si <pb xlink:href="020/01/032.jpg" pagenum="13"/>mise per entro alla ingente mole di manoscritti che rimangono a testificare <lb/>della attivit&agrave; dei discepoli di Galileo e di quella dell'Accademia del Cimento, <lb/>risultarono in tanta copia cose nuove, anzi nemmeno sospettate: e quei <lb/>sommi, la cui luce era in certo qual modo ecclissata dal risplendere del&shy;<lb/>l'astro maggiore, apparvero a lui in tutta la effettiva loro grandezza, do&shy;<lb/>veva egli serbare anco rispetto ad essi un p&ograve; di quel <emph type="italics"/>rationabile obseqium<emph.end type="italics"/><lb/>non sempre a proposito adoperato rispetto a Galileo. </s>

<s>Ma questi documenti <lb/>gli mancarono per fondarvi gli entusiastici giudizi ch'egli formula sul Sarpi; <lb/>imperocch&egrave; al nostro autore, di documenti cos&igrave; sottile ed acuto indagatore, <lb/>non pu&ograve; essere sfuggito che questi, nello stretto senso della parola, gli fa&shy;<lb/>cevano difetto per giudicare l'opera scientifica del celebre Consultore della <lb/>Serenissima, e che le relazioni postume d'altri, anzi le stesse sue dichiara&shy;<lb/>zioni, vanno accolte col benefizio dell'inventario, imperocch&egrave; un ben me&shy;<lb/>schino concetto del Sarpi scienziato ci faremmo noi, se, come egli afferma, <lb/>dovessimo credere che parlasse o scrivesse delle scoperte annunziate dal <lb/><emph type="italics"/>Sidereus Nuncius<emph.end type="italics"/> senza c&ugrave;rarsi di leggerlo! Del rimanente, troppo era im&shy;<lb/>merso il Sarpi negli affari di Stato, sicch&egrave; gli rimanesse il tempo neces&shy;<lb/>sario a tener dietro al potentissimo impulso che allora appunto ricevevano <lb/>le scienze matematiche e naturali: e riconosciamo volentieri, che la mente <lb/>potentissima pot&egrave; suggerirgli idee e concetti originali ed innovatori, i quali <lb/>per&ograve;, essendo monchi per difficolt&agrave; di gestazione, rimasero per la maggior <lb/>parte infecondi. </s>

<s>Di qui, adunque, al fare del Sarpi l'institutore della prima <lb/>accademia sperimentale che sia stata in Italia, il precursore del Gilbert, l'i&shy;<lb/>spiratore di Galileo, come pretenderebbe il nostro, ci corre e di molto. </s></p><p type="main">

<s>E, discendendo a cose pi&ugrave; minute, ci pare di poter osservare che tal&shy;<lb/>volta (bench&egrave; assai di rado) gli sia accaduto di non attingere proprio alle <lb/>fonti prime, come, per modo di esempio, nella istoria dei metodi primi di <lb/>osservazione delle macchie solari, ed ancora l&agrave; dove con qualche inesattezza <lb/>accenna alle esperienze del Keplero per determinare la ragione dell'angolo <lb/>d'incidenza all'angolo di rifrazione di un raggio di luce che dall'aria passa <lb/>nel vetro; ed in genere anche in qualche altro argomento di ottica, nella <lb/>quale l'Autore ci sembra essere meno profondo in confronto di altri argo&shy;<lb/>menti. </s>

<s>E ci&ograve; che avvertiamo rispetto alle fonti, ripeteremmo volontieri per <lb/>certi apprezzamenti. </s>

<s>Cosl, sempre per modo di esempio, della regolare suc&shy;<lb/>cessione delle fasi di Venere, come modo per determinare il periodo della <lb/>sua rotazione, ci sembra ch'egli parli con qualche leggerezza; cos&igrave; ancora <lb/>egli vorr&agrave; concederci che, quantunqe lo neghi, possano molto pi&ugrave; propria&shy;<lb/>mente dirsi microscopi quelle palline di vetro, colle quali tutti ricordiamo <lb/>di esserci trastullati nella nostra adolescenza, che non sia somiglianza, la <lb/>quale pure egli vorrebbe vedere, tra un pozzo ed un cannocchiale. </s></p><p type="main">

<s>Queste poche, fra molte altre osservazioni di simil genere, le quali <lb/>pure potrebbero farsi, abbiamo voluto notare, poich&egrave; a quelle della prima <lb/>categoria egli potr&agrave; facilmente ovviare con una pi&ugrave; frequente e regolare ci&shy;<lb/>tazione delle fonti, e fors'anche con una pi&ugrave; accurata critica di esse, ed a <pb xlink:href="020/01/033.jpg" pagenum="14"/>quelle della seconda baster&agrave; certamente l'avervi richiamata sopra la d&igrave; lui <lb/>attenzione. </s>

<s>Enumerare distintamente tutti i punti, nei quali non ci trove&shy;<lb/>ressimo completamente d'accordo coll'autore, non &egrave; n&egrave; nostro ufficio, n&egrave; <lb/>nostro assunto. </s></p><p type="main">

<s>E poich&egrave; vogliamo finirla colle censure, aggiungeremo ancora, che non <lb/>siamo d'accordo col nostro autore in certi criteri di selezione, ch'egli vor&shy;<lb/>rebbe adottati l&agrave; dove parla della pubblicazione dei manoscritti vinciani: n&egrave; <lb/>avremmo notata questa, che potr&agrave; anco essere stimata una minuzia, se non <lb/>vi vedessimo per entro una questione generale e di altissima importanza. </s>

<s>&mdash; <lb/>Giusti sono gli appunti che egli fa ai primi editori del trattato di Leonardo <lb/>intorno al moto ed alla misura delle acque; ma quando, alla sua volta, egli <lb/>applica il suo principio di selezione ad un nuovo ordinamento di questa <lb/>magistrale scrittura, &egrave; egli proprio ben certo di essere penetrato nelle in&shy;<lb/>tenzioni dell'autore? </s>

<s>o piuttosto non &egrave; ragionevole il timore di aver sosti&shy;<lb/>tuito, al pensiero di quello, il proprio? </s>

<s>e che altri venga poi collo stesso <lb/>principio, e creda di farsene pi&ugrave; fedele interprete con l'adottare criteri di&shy;<lb/>versi di selezione? </s>

<s>Che mai ne verrebbe di tutte le cose vinciane, anzi <lb/>di quello stesso Codice Atlantico, il quale, del resto, &egrave; cosa ben diversa <lb/>da quello che mostra di credere il nostro autore, qualora nella pubblicazione <lb/>di esse prevalesse un tale indirizzo? </s>

<s>Quando dieci studiosi avessero fatto <lb/>sui manoscritti di Leonardo un lavoro analogo a quello che vi condusse il <lb/>Richter, oppure anche adottando i pi&ugrave; perfetti criteri di selezione, rimar&shy;<lb/>rebbe pur sempre il desiderio della pubblicazione integrale e diplomatica, <lb/>poich&egrave; ognuno vuole giudicare da s&egrave;, e quello che a taluno sfugge, perch&egrave; <lb/>stimato di poco momento, colpisce tal altro che, in un ordine alquanto di&shy;<lb/>verso di idee, lo stima importante; n&egrave; l'uomo coscienzioso di studio lascier&agrave; <lb/>mai in pace quelle carte preziose: e rinunzier&agrave; di risalire agli originali sol&shy;<lb/>tanto allora, che ne sia stata condotta una edizione conforme a quella che <lb/>il Ravaisson-Mollien sta pubblicando, e che per il Codice Atlantico il non <lb/>mai abbastanza compianto nostro Govi preparava, facendo opera egregia, de&shy;<lb/>gna della patria di Leonardo, e del Re che la promuoveva. </s></p><p type="main">

<s>Queste cose abbiamo voluto notare, perch&egrave;, con qualche altra di minor <lb/>conto, nell'insieme bene armonizzato di questo ragguardevolissimo lavoro, <lb/>ci parvero vere stuonature: &ldquo; un corno, un obo&egrave; fuori di chiave &rdquo; in mezzo <lb/>ad un concerto che nel suo complesso appaga lo spirito, sodisfa la mente e <lb/>delizia le orecchie. </s>

<s>Ed &egrave; invero deliziato il lettore, oltre che dalla sostanza, <lb/>dalla forma data all'opera poderosa. </s>

<s>L'Autore, in certo punto del suo lavoro <lb/>si dice &ldquo; nato per fortuna sulle rive dell'Arno &rdquo;: dichiarazione superflua, <lb/>poich&egrave;, pur non sapendolo, avremmo potuto dirgli: </s></p><p type="main">

<s><emph type="center"/>&ldquo; La tua loquela ti fa manifesto <lb/>Di quella nobil patria nat&igrave;o &rdquo;.<emph.end type="center"/></s></p><p type="main">

<s>E con uno stile piano e semplice, con una lingua perfetta, con una <lb/>forma che incanta e seduce, e ricorda, senza ombra di esagerazione, quella <pb xlink:href="020/01/034.jpg" pagenum="15"/>dei grandi, i quali dal suo lavoro rimangono irradiati di novella luce, che <lb/>rende meno ispide le non infrequenti dimostrazioni matematiche e mecca&shy;<lb/>niche, &egrave; condotto il lavoro tutto intero, poich&egrave; del vastissimo campo pu&ograve; <lb/>ben dirsi che nessun angolo rimanga inesplorato. </s></p><p type="main">

<s>Dei <emph type="italics"/>principali strumenti del metodo sperimentale<emph.end type="italics"/> indaga la storia del <lb/>termometro, dell'orologio a pendolo, dei cannocchiali di Galileo, del Fon&shy;<lb/>tana, del Torricelli e del telescopio a riflessione, del micrometro, del bino&shy;<lb/>culo, del barometro, dell'igrometro, del corno acustico, del pluviometro, del <lb/>microscopio, dell'areometro e di altri macchinamenti ingegnosi e curiosi, <lb/>nei quali possono ravvisarsi i germi di altri maggiori strumenti, che diedero <lb/>celebrit&agrave; a pi&ugrave; recenti inventori. </s></p><p type="main">

<s>Studiando la <emph type="italics"/>storia del metodo sperimentale applicato alle scienze fisi&shy;<lb/>che,<emph.end type="italics"/> ne indaga specificatamente le vicende rispetto all'ottica, alla catottrica, <lb/>alla dottrica, alle diffrazioni ed alle interferenze, al suono, al calore, al ma&shy;<lb/>gnetismo, alla meteorologia, alla geografia, alla cosmografia, all'astronomia <lb/>dei pianeti ed a quella del sole, della luna e delle comete. </s></p><p type="main">

<s>La <emph type="italics"/>storia del metodo sperimentale applicato alla storia naturale<emph.end type="italics"/> stu&shy;<lb/>dia, esaminandone gli effetti sullo svolgimento dell'anatomia, dell'entomo&shy;<lb/>logia, e dedica speciali ricerche alla circolazione del sangue, alla meccanica <lb/>dei moti interni, all'ematosi, alla meccanica animale dei movimenti locali, <lb/>agli organi dei sensi, alla medicina sperimentale, alla fisiologia delle piante <lb/>ed ai sistemi di loro classificazione, e per ultimo alla geologia. </s>

<s>In questa <lb/>cos&igrave; ricca rassegna potrebbero per verit&agrave; notarsi alcune lacune; ma, come <lb/>gi&agrave; si &egrave; avvertito, furono dall'autore lasciate ad arte, affinch&egrave; rimanessero <lb/>impregiudicate le questioni che hanno attinenza colla seconda e colla terza <lb/>parte del lavoro (alle quali, come s'&egrave; detto, sono respettivamente dedicati il <lb/>secondo ed il terzo volume), vale a dire colla storia del metodo sperimen&shy;<lb/>tale applicato alla scienza del moto dei gravi, ed alla scienza del moto delle <lb/>acque. </s></p><p type="main">

<s>E quanto alla seconda parte ecco, colla maggior possibile brevit&agrave;, come <lb/>essa si appresenti al nostro autore. </s></p><p type="main">

<s>Gli studi del moto, bench&egrave; fossero da altri, sopra gli insegnamenti di <lb/>Archimede, in qualche modo iniziati, non presero nulladimeno ordinamento <lb/>di scienza, prima di Galileo, il quale, in un trattatello, che corse a principio <lb/>manoscritto, illustr&ograve; e complet&ograve; la teoria delle macchine, e in altre scrit&shy;<lb/>ture svolse e formul&ograve; i principii archimedei dei moti equabili. </s>

<s>Indagando <lb/>tuttavia il cammino, che, su questa via, erasi percorso dai predecessori del <lb/>sommo filosofo, avverte il nostro che nessuno aveva pensato di comporre <lb/>un trattatello compiuto di meccanica, a quel modo che si fece dell'idraulica, <lb/>servendosi dei materiali dispersi per i manoscritti di Leonardo da Vinci; <lb/>questo fece l'autore, tenendo conto di ci&ograve; che ormai si ha alle stampe, e <lb/>giova credere che pregevoli aggiunte gli saranno fornite dalle cose vinciane <lb/>pubblicate posteriormente alla presentazione di questo lavoro. </s>

<s>Il trattato poi <lb/>della <emph type="italics"/>Nuova Scientia<emph.end type="italics"/> del Tartaglia, conosciuto, ma non curato da Galileo, <pb xlink:href="020/01/035.jpg" pagenum="16"/>diligentemente analizzato, apparisce meritevolissimo di storia; e bench&egrave; il <lb/>matematico bresciano non riuscisse a scoprire la legge dei moti accelerati e <lb/>le vere curve descritte dai proietti, apparisce nulladimeno mirabile che tanto <lb/>assottigliasse la geometria da costringerla a rivelargli che la massima am&shy;<lb/>piezza del tiro avviene quando l'obice &egrave; inclinato all'orizzonte di 45.&deg; </s></p><p type="main">

<s>Or dunque i primi studi di Galileo il nostro autore ce li mostra ri&shy;<lb/>volti ad assicurarsi dell'errore aristotelico, che teneva le velocit&agrave; dei gravi <lb/>cadenti esser proporzionali alla quantit&agrave; di materia. </s>

<s>E, <gap/>yocata ad esame <lb/>la famosa leggenda della lampada nel Duomo di Pisa, pone m luce la sot&shy;<lb/>tigliezza mirabile dell'argomentazione di Galileo, il quale pronunzi&ograve; sicura&shy;<lb/>mente, contro Aristotile, quel che non poteva essere confermato che dal&shy;<lb/>l'uso della macchina pneumatica, che cio&egrave; i gravi nel vuoto scenderebbero <lb/>tutti in egual tempo, qualunque pure si fosse la loro mole e la loro materia. </s></p><p type="main">

<s>Nell'investigare la legge sopra esposta, Galileo era stato preceduto da <lb/>altri matematici, come dal Moletti e dal Benedetti: nello studio dei moti <lb/>equabili pure era stato prevenuto da Archimede o dai numerosi seguaci di <lb/>lui. </s>

<s>Rimaneva a scoprir la legge dei moti accelerati, tentata prima invano <lb/>da tutti. </s>

<s>E Galileo vi si prepar&ograve; col chiarirsi bene in mente il principio <lb/>d'inerzia, unico fondamento della scienza del moto. </s>

<s>Vuole l'autor nostro che <lb/>il pendolo non sia stato da principio per Galileo se non uno strumento <lb/>sperimentatore della legge dei gravi cadenti, e che, sperimentando, siasi av&shy;<lb/>veduto dell'isocrinismo delle vibrazioni di esso, del qual fatto voleva Galileo <lb/>stesso ritrovar la dimostrazione matematica, ma non riusciva a spuntarla; <lb/>n&egrave; lo spuntarla, per verit&agrave;, era possibile, non potendo la matematica dimo&shy;<lb/>strargli vero quel che la fisica stessa gli accennava esser falso. </s>

<s>Ma, qual ri&shy;<lb/>compensa di questi suoi lunghi ed ostinati studi, ebbe la scoperta del bra&shy;<lb/>chistocronismo degli archi rispetto alle corde. </s></p><p type="main">

<s>Da questo argomento, nel quale il nostro autore giunge a conchiusioni <lb/>importanti e, almeno in parte, nuove, passa a considerare la teoria dei <lb/>proietti, la quale, lasciata a mezzo dal Tartaglia, fu ripresa da Galileo nei <lb/>primi suoi studi giovanili. </s>

<s>Ci narra come fossero incerti que'primi passi e <lb/>fallaci, e pi&ugrave; tontani dal vero di quel che ne fossero gli stessi suo&igrave; prede&shy;<lb/>cessori. </s>

<s>Ripigliando il soggetto de'moti accelerati ci descrive l'esperienza <lb/>galileiana che condusse il suo autore ad accertarsi come veramente gli spazi <lb/>sono proporzionali ai quadrati dei tempi, e ci narra in che modo Galileo <lb/>stesso riuscisse alla dimostrazione matematica di questa nuova legge da s&egrave; <lb/>scoperta, ammettendo che le velocit&agrave; son sempre e costantemente in ragion <lb/>del tempo. </s></p><p type="main">

<s>Dopo la dimostrazione della legge dei moti accelerati, mostra occorsa a <lb/>Galileo una nuova scoperta sui proietti, la quale consisteva nell'avere ritro&shy;<lb/>vato per esperienza che il proietto stesso descrive la curva in quel mede&shy;<lb/>simo tempo, che abbandonato a s&egrave;, per impulso della gravit&agrave; naturale, <lb/>avrebbe passato il perpendicolo. </s></p><p type="main">

<s>Narrati cos&igrave; i particolari storici di questa scoperta, passa il nostro Au-<pb xlink:href="020/01/036.jpg" pagenum="17"/>tore a far la storia di altre scoperte galileiane non meno importanti, e son <lb/>quelle che risguardano la resistenza dei solidi allo spezzarsi. </s>

<s>Di questi nuovi <lb/>studi meccanici si contano qui i princip&igrave;, e si risguardano come precipua <lb/>parte del trattato <emph type="italics"/>De motu,<emph.end type="italics"/> rimasto, fino a questi ultimi tempi, inedito, e <lb/>a cui poi supl&igrave; l'autore colla pubblicazione de'<emph type="italics"/>Dialoghi delle due Nuove <lb/>Scienze.<emph.end type="italics"/></s></p><p type="main">

<s>Giudicasi pertanto in questa storia, la quale noi andiamo fedelmente <lb/>seguendo, che non piacendo a Galileo la forma latina e l'ordine dato alle <lb/>prime scritture <emph type="italics"/>De motu,<emph.end type="italics"/> e d'altra parte le questioni astronomiche recla&shy;<lb/>mando pi&ugrave; sollecita pubblicazione delle meccaniche, ne'<emph type="italics"/>Dialoghi dei due <lb/>Massimi Sistemi<emph.end type="italics"/> avrebbe pensato di inserirvi tutte le scoperte da lui fatte <lb/>infino a quel tempo, rispetto alle propriet&agrave; ed alle leggi dei moti, ed &egrave; <lb/>perci&ograve; che non trovando quivi nemmeno il pi&ugrave; lontano sentore che la curva <lb/>di proiezione potesse essere una parabola, &egrave; condotto il nostro alla tratta&shy;<lb/>zione erronea, della quale abbiamo gi&agrave; tenuto parola, rispetto alla parte che <lb/>in questa scoperta egli vorrebbe fare al Cavalieri. </s></p><p type="main">

<s>Segue in appresso accuratamente tracciata la storia dei dialoghi ma&shy;<lb/>noscritti dello Nuove Scienze e delle vicende sub&igrave;te nella loro pubblicazione, <lb/>narrando in particolar modo come riuscisse a Galileo di dimostrare la se&shy;<lb/>conda e terza legge dei moti pendolari, e come, soltanto allora, secondo che <lb/>il nostro opina, pensasse di servirsene alla misura dei minimi tempi; inve&shy;<lb/>stigando poi e svolgendo quel sottilissimo filo di dimostrazioni, che, dipen&shy;<lb/>dendo da due o tre proposizioni fondamentali, compongono il terzo dialogo <lb/>di esse Nuove Scienze, chiarisce qual si fosse il primo processo dello di&shy;<lb/>mostrazioni di Galileo sui numerosi teoremi dei moti accelerati, come questo <lb/>processo fosse emendato nella pubblicazione del terzo dialogo surriferito, e <lb/>come, dopo la pubblicazione, coll'aiuto del Torricelli, pensasse a dare altro <lb/>ordine e pi&ugrave; chiarezza alle sue dimostrazioni, quando a quella di Leida <lb/>avessero dovuto succedere altre edizioni. </s></p><p type="main">

<s>Il confronto fra le dimostrazioni sui proietti pubblicate, e le anteriori <lb/>e le posteriori alla pubblicazione di Leida, rimaste quest'ultime manoscritte <lb/>nei codici galileiani, e la dimostrazione data dal sommo filosofo della com&shy;<lb/>posizione delle forze richiamano in appresso tutta l'attenzione del nostro <lb/>autore. </s></p><p type="main">

<s>Alla prima edizione di Leida, che si componeva di soli quattro dialoghi, <lb/>se ne aggiunsero dagli editori seguenti altri due: il quinto che &egrave; della <lb/>scienza universale delle proporzioni, e il sesto della forza della percossa. </s>

<s><lb/>Del ritrovamento e delle vicende sub&igrave;te dal manoscritto di questo ultimo dia&shy;<lb/>logo o Congresso, come chiamavalo Galileo, &egrave; fatto soggetto particolare di <lb/>storia, concludendo che egli lo ripudi&ograve;, e che, quando non lo avesse cos&igrave; <lb/>ripudiato, quel dialogo doveva andare in ordine il quinto e non il sesto. </s></p><p type="main">

<s>Stabilito poi, come uno dei fondamenti dell'edifizio galileiano fosse il <lb/>principio che due gravi hanno acquistato una ugual velocit&agrave;, dopo essere <lb/>scesi per due diverse linee, le quali per&ograve; abbiano una medesima caduta, <pb xlink:href="020/01/037.jpg" pagenum="18"/>principio dapprima supposto per vero, si mostra, come, dopo la pubblica&shy;<lb/>zione dei dialoghi, riuscisse a Galileo di trovare quella dimostrazione, e come <lb/>la divulgasse fra gli amici e gli scolari. </s></p><p type="main">

<s>Dopo i dialoghi delle Nuove Scienze sono presi in esame il trattato del <lb/>Baliani, ponendo in chiaro come da esso differisca quello del Torricelli, e <lb/>tutta la importanza che rivestono quelli del Borelli, e dimostrandosi come, <lb/>se fossero noti al mondo i manoscritti del Viviani, apparirebbe assai pi&ugrave; <lb/>evidente com'egli fu dei primi, dei pi&ugrave; assidui e de'pi&ugrave; strenui propugna&shy;<lb/>tori e promulgatori delle dottrine galileiane concernenti la scienza del moto. </s></p><p type="main">

<s>Infine l'autore nostro ha voluto prendere in esame alcune difficolt&agrave; pro&shy;<lb/>mosse contro le dottrine galileiane dagli scienziati stranieri intrattenendosi pi&ugrave; <lb/>particolarmente a far rilevare le incongruenze e gli invidiosi fastidi cartesiani. </s></p><p type="main">

<s>Ed ora, con analisi altrettanto rapida, prendiamo in esame il terzo ed <lb/>ultimo volume. </s></p><p type="main">

<s>Come ogni parte di scienza sperimentale in Italia incomincia con Ga&shy;<lb/>lileo, cos&igrave; il nostro autore d&agrave; principio alla storia dell'applicazione di essa <lb/>alle dottrine intorno al moto delle acque, esponendo le speculazioni e le espe&shy;<lb/>rienze, colle quali il nuovo Archimede promosse la scienza dell'equilibrio <lb/>de'liquidi, iniziata gi&agrave; dall'Archimede antico. </s>

<s>Passa poi a narrare come e <lb/>quando il Castelli riuscisse a formulare ed a dimostrare geometricamente le <lb/>proposizioni fondamentali di questa scienza, che cio&egrave; le quantit&agrave; dell'acqua <lb/>fluente da una luce son proporzionali alla velocit&agrave; moltiplicata per la se&shy;<lb/>zione; narrando poi come, da questa, il Castelli stesso svolgesse una serie <lb/>di proposizioni o teoremi, che compongono il primo libro della <emph type="italics"/>misura delle <lb/>acque correnti.<emph.end type="italics"/></s></p><p type="main">

<s>Opportunamente avverte l'autore, che il Bisenzio fu in Toscana il primo <lb/>fiume, a cui si applicassero le nuove leggi idrauliche gi&agrave; scoperte, e perci&ograve; <lb/>egli prende a narrare l'occasione ed il modo particolare di questa applica&shy;<lb/>zione; e, sottoponendo a diligente esame storico-critico le dottrine meccanico&shy;<lb/>idrauliche professate da Galileo nella lettera o trattato del fiume Bisenzio, <lb/>discute la celebre questione insorta fra lui e Andrea Arrighetti. </s>

<s>Con altret&shy;<lb/>tanta diligenza viene poi esaminata l'altra delle scritture idrauliche galileiane <lb/>rimasteci, cio&egrave; il breve discorso contro il Bertizzolo. </s>

<s>Ritorna poi al Castelli, <lb/>il quale, preparandosi con speculazioni ed esperienze nuove a risolvere la <lb/>questione della laguna veneta, s'abbatt&egrave; a scoprire un fatto, nella dimo&shy;<lb/>strazione del quale lo sovvenne il Cavalieri; e degli incidenti a questo ar&shy;<lb/>gomento relativi &egrave; fornita una narrazione particolareggiata ed importante. </s></p><p type="main">

<s>Il regolamento delle Chiane, morto Galilei, fu uno dei primi e princi&shy;<lb/>pali problemi offertisi a risolvere a'discepoli di lui. </s>

<s>Il Michelini proponeva, <lb/>per velocitarne il corso, di abbassar lo sbocco del fiume; il Torricelli si op&shy;<lb/>poneva, propugnando il principio che le velocit&agrave; sono da regolarsi, non se&shy;<lb/>condo il declivio dell'alveo, ma della superficie dell'acqua. </s>

<s>Le fasi diverse <lb/>di questo dibattito sono accuratamente studiate dal nostro autore nelle cause <lb/>e nelle conseguenze. </s></p><pb xlink:href="020/01/038.jpg" pagenum="19"/><p type="main">

<s>Il secondo libro del Castelli, essendo postumo, qui, coll'appoggio prin&shy;<lb/>cipale di inediti documenti, si fa la storia del manoscritto, si narra come, <lb/>e fino a qual punto, lo pubblicasse il Barattieri, e si passa po&igrave; a far la storia <lb/>della pubblicazione del Dozza, nella quale storia si narrano fedelmente, per <lb/>la prima volta, le emendazioni della proposizione seconda: emendazioni pro&shy;<lb/>poste dal principe Leopoldo, da poi che si avvert&igrave; che la legge della velo&shy;<lb/>cit&agrave; conclusa in quella stessa proposizione, non consentiva con quell'altra <lb/>scoperta e dimostrata dal Torricelli. </s></p><p type="main">

<s>Il nome di Gio. </s>

<s>Battista Barattieri &egrave; assai ben noto nella scienza; ma <lb/>ignorasi quasi affatto quello del discepolo di Galileo, Cosimo Noferi, la <emph type="italics"/>Tra&shy;<lb/>vagliata Architettura<emph.end type="italics"/> del quale &egrave; rimasta inedita, in quattro volumi. </s>

<s>Sem&shy;<lb/>brando pertanto al nostro autore che fossero meritevoli di qualche notizia, <lb/>egli vien rendendone conto. </s>

<s>In molti particolari entra egli in appresso ri&shy;<lb/>spetto a Famiano Michelini ed alla storia del famoso trattato della <emph type="italics"/>Direzione <lb/>dei fiumi,<emph.end type="italics"/> principalmente per ci&ograve; che concerne il principio in esso profes&shy;<lb/>sato e per il quale l'acqua eserciterebbe tutta la sua pressione sul fondo e <lb/>pochissimo o nulla sulle sponde del vaso. </s>

<s>Del principio della eguaglianza <lb/>delle pressioni ignorato dal Michelini e da molti altri de'nostri italiani, <lb/>viene attribuito il merito della scoperta al Pascal; ma si dimostra qui che <lb/>il Torricelli l'aveva trovato parecchi anni prima e ne aveva fatta l'applica&shy;<lb/>zione al barometro. </s>

<s>Vincenzio Viviani &egrave; conosciuto solamente per i suoi di&shy;<lb/>scorsi di idraulica pratica relativi al regolamento dell'Arno; ma che fosse <lb/>uno dei pi&ugrave; infaticabili in idrometria, confermando con nuove dimostra&shy;<lb/>zioni geometriche e con nuove esperienze i princip&igrave; del Torricelli, espone <lb/>e dimostra il nostro autore, producendone ed illustrandone gli scritti ine&shy;<lb/>diti: il quale poi ci addita in Geminiano Montanari il primo che applicasse <lb/>la scienza all'idrografia dei mari, ed in Bernardino Ramazzini lo scopritore <lb/>dei pozzi artesiani. </s></p><p type="main">

<s>L'idrometria restava tuttavia incerta fra la legge supposta dal Castelli <lb/>e la dimostrata dal Torricelli: e qui il nostro autore segnala l'intervento <lb/>del Cassini, i cui progressi idraulici sono diligentemente narrati, notandosi <lb/>come intorno a questo tempo entrino ad ingerirsi di tali studi anco gli stra&shy;<lb/>nieri, fra i quali il Varignon, di cui si dimostrano gli errori commessi in <lb/>voler analiticamente confermare la legge delle velocit&agrave; scoperta dal Torri&shy;<lb/>celli. </s>

<s>Detto della invenzione degli idrometri, entra a discorrere del trattato <lb/>del Guglielmini sulla misura delle acque correnti, in cui si introducono per <lb/>la prima volta nell'idrometria le velocit&agrave; medie e si conferma con nuove e <lb/>solenni esperienze la legge torricelliana; nonch&egrave; delle tre celebri lettere <lb/>idrostatiche, nelle quali esso Guglielmini si difende contro le imputazioni del <lb/>Papin, sciogliendo il problema nuovo delle velocit&agrave; dell'acqua ne'tubi pieni. </s>

<s><lb/>E, nel narrare questa parte di storia, nota il nostro autore come, a propo&shy;<lb/>sito dell'intervento della pressione dell'aria in que'fatti idraulici, prendesse il <lb/>Guglielmini occasione di illustrare magistralmente la teoria del barometro. </s></p><p type="main">

<s>N&egrave; sono trascurate le applicazioni che all'idraulica fece dei teoremi di <pb xlink:href="020/01/039.jpg" pagenum="20"/>meccanica il Grandi, n&egrave; le contribuzioni del Poleni allo studio delle leggi <lb/>d'efflusso attraverso alle diverse figure di tubi addizionali, n&egrave; gli sperimenti <lb/>del Michelotti, e nemmeno i fiumi artificiali del Genetti. </s></p><p type="main">

<s>L'origine dei fiumi, che fu gi&agrave; soggetto di poema, si fa or qui sog&shy;<lb/>getto di storia, prima di parlar della legge degli alvei, dentro cui scorrono <lb/>i fiumi. </s>

<s>Notasi in appresso che prima di Galileo e del Guglielmini, gli idrau&shy;<lb/>lici, rispetto agli alvei, versavano in molti errori, i quali furono tolti di <lb/>mezzo, ed &egrave; minutamente narrato come riuscisse al Guglielmini di asse&shy;<lb/>gnare le leggi allo stabilirsi degli alvei stessi. </s></p><p type="main">

<s>Col trattato della natura dei fiumi il nostro Autore ci mostra compiuto <lb/>il grande edifizio iniziato nelle poche pagine del Castelli. </s>

<s>I successori del <lb/>Guglielmini egli ce li addita intenti a confermare e ad illustrare le dottrine <lb/>di lui, nella quale opera designa particolarmente il Manfredi, lo Ximenes, <lb/>il Lecchi, lo Zendrini, il Frisi e il Perelli, di ciascun dei quali rende bre&shy;<lb/>vemente conto in quest'ultimo capitolo della sua storia. </s></p><p type="main">

<s>Ora, nonostante la vastit&agrave;, la quale, senza ombra di esagerazione, &egrave; da <lb/>dirsi imponente, di questo lavoro, che l'autore vorr&agrave; certamente corredare <lb/>di copiosi indici per nomi e per materie, possiamo noi conchiudere che esso <lb/>risolva completamente il quesito, quale fu posto dall'Istituto? </s>

<s>A questo <lb/>dobbiamo sinceramente rispondere che, mentre il quadro delle origini e <lb/>dello sviluppo del metodo sperimentale in Italia &egrave; magistralmente condotto <lb/>fino agli ultimi discepoli, anzi quasi fino agli ultimi discepoli dei discepoli <lb/>di Galileo, pure esso non &egrave; proseguito fino a comprendervi la scoperta della <lb/>pila voltaica, come tassativamente era stato dall'Istituto richiesto. </s></p><p type="main">

<s>Ma altrettanto sinceramente dobbiamo dichiarare, che quella monografia, <lb/>per modo di dire pi&ugrave; ristretta, alla quale la vostra Giunta aveva esplicita&shy;<lb/>mente accennato nell'aprire per la seconda volta il concorso, e la quale si <lb/>convenne sarebbe tornata bene accetta all'Istituto ed avrebbe potuto essere <lb/>giudicata meritevole di premio, viene ad essere ad esuberanza rappresentata, <lb/>e in modo che, toltene alcune mende, non potrebbe, per originalit&agrave; di ri&shy;<lb/>cerche, profondit&agrave; di vedute e coscienza di studi desiderarsi migliore, da <lb/>questo lavoro: e che noi stimiamo per esso pienamente soddisfatta la volont&agrave; <lb/>del testatore, dal quale l'Istituto ebbe incarico di conferire il premio: <emph type="italics"/>&ldquo; a <lb/>chi detter&agrave; meglio la storia del metodo sperimentale in Italia &rdquo;.<emph.end type="italics"/></s></p><p type="main">

<s>Venezia, li 16 febbraio 1890. </s></p><p type="main">

<s>Dott. </s>

<s>ANGELO MINICH </s></p><p type="main">

<s>GIUSEPPE LORENZONI <lb/></s></p><p type="main">

<s>ANTONIO FAVARO <emph type="italics"/>Relatore.<emph.end type="italics"/></s></p><pb xlink:href="020/01/040.jpg"/><p type="main">

<s><emph type="center"/>AVVERTIMENTO<emph.end type="center"/></s></p><p type="main">

<s>Citiamo, coll'abbreviatura <emph type="italics"/>Alb.,<emph.end type="italics"/> l'opere complete di Galileo stampate in Firenze, dal <lb/>1842 al 1856, dalla societ&agrave; editrice fiorentina, in quindici tomi, con pi&ugrave; un tomo di <emph type="italics"/>Sup&shy;<lb/>plemento,<emph.end type="italics"/> sotto la direzione di Eugenio Alb&egrave;ri. </s>

<s>Il numero romano indica il tomo, l'arabo <lb/>la pagina. </s></p><p type="main">

<s>I manoscritti galileiani, esistenti nella R. </s>

<s>Biblioteca Nazionale di Firenze, si citano <lb/>colla seguente abbreviatura: <emph type="italics"/>MSS. Gal. </s>

<s>Divis.... P.... T.... c....<emph.end type="italics"/> che vuol dire <emph type="italics"/>Ma&shy;<lb/>noscritti galileiani, Divisione.... Parte.... Tomo .... carle ....<emph.end type="italics"/></s></p><p type="main">

<s>Coll'abbreviatura <emph type="italics"/>MSS. Gal. </s>

<s>Disc.<emph.end type="italics"/> s'indica la Divisione IV dei medesimi Manoscritti <lb/>appartenenti ai varii e numerosi Discepoli di Galileo, e il numero romano indica il tomo, <lb/>l'arabo la carta. </s></p><p type="main">

<s>Per l'abbreviatura in ultimo <emph type="italics"/>MSS. Cim.<emph.end type="italics"/> s'indica la Divisione V, che &egrave; dei Poste&shy;<lb/>riori di Galileo o degli Accademici del Cimento, e, al solito, co'due numeri che segui&shy;<lb/>tano appresso s'accenna al tomo corrispondente e alla carta. </s></p><p type="main">

<s>Perch&egrave; poi gli studiosi, che volessero riscontrare le nostre citazioni sui Manoscritti, <lb/>sentiranno il bisogno di rilevarne pi&ugrave; largamente il senso da tutto il contesto, abbiamo <lb/>creduto inutile, citando la carta, d'indicar se il passo trascritto o accennato si trovi pre&shy;<lb/>cisamente nella prima fronte o nel tergo. </s></p><p type="main">

<s>Spesso, di alcuni documenti che videro la pubblica luce, per opera del Nelli, del Tar&shy;<lb/>gioni, del Fabbroni e di altri, citiamo il Manoscritto, piuttosto che la stampa, e ci&ograve; si fa <lb/>da noi, quando i Documenti stessi non sieno stati pubblicati con quella integrit&agrave; o con <lb/>quella fedelt&agrave;, che, a parer nostro, richiedeva l'importanza del soggetto. <pb xlink:href="020/01/041.jpg"/></s></p><pb xlink:href="020/01/042.jpg"/><p type="main">

<s><emph type="center"/>DELL'ORIGINE E DE'PROGRESSI<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>DEL<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>METODO SPERIMENTALE IN ITALIA<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>DISCORSO PRELIMINARE<emph.end type="center"/><pb xlink:href="020/01/043.jpg"/></s></p><pb xlink:href="020/01/044.jpg"/><p type="main">

<s><emph type="center"/>PARTE PRIMA<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>SOMMARIO.<emph.end type="center"/></s></p><p type="main">

<s>I. </s>

<s>Del primo acquisto delle cognizioni. </s>

<s>&mdash; II. </s>

<s>Platone e Aristotile. </s>

<s>&mdash; III. </s>

<s>Della Filosofia naturale de&shy;<lb/>rivata dall'Accademia e dal Peripato &mdash; IV. </s>

<s>Come le due Filosofie, la platonica e l'aristotelica, <lb/>venissero a introdursi nella Societ&agrave; cristiana. </s>

<s>&mdash; V. De'medici peripatetici: Girolamo Fracastoro, <lb/>Andrea Cisalpino. </s>

<s>&mdash; VI Girolamo Cardano, Giuseppe Scaligero, Niccol&ograve; Tartaglia. </s>

<s>&mdash; VII. </s>

<s>Dei <lb/>filosofi razionalisti: Francesco Patrizio, Bernardino Telesio, Giordano Bruno e Tommaso Cam&shy;<lb/>panella &mdash; VIII. De'frutti di scienza naturale raccolti nel secolo XVI dalle tre Filosofie, acca&shy;<lb/>demica, peripatetica e razionalistica. </s>

<s>&mdash; IX. De'cultori dell'arte, veri precursori del metodo <lb/>sperimentale; Dante Alighieri, Leon Battista Alberti, Cristoforo Colombo e Amerigo Vespucci. </s>

<s>&mdash; <lb/>X. </s>

<s>Leonardo da Vinci &mdash; XI. </s>

<s>Degli anatomici padovani del secolo XVI, e segnatamente di <lb/>Realdo Colombo &mdash; XII. </s>

<s>Come nel secolo XVI gli esercizi sperimentali e le notizie dei fatti <lb/>naturali si diffondessero dai libri d'uomini letterati: Giovan Battista Porta e Ferrante Impe&shy;<lb/>rato. </s>

<s>&mdash; XIII. De'pi&ugrave; immediati precursori e cooperatori alla grande Instaurazione galileiana: <lb/>Giovan Battista Benedetti e Santorre Santorio. </s>

<s>&mdash; XIV. </s>

<s>Paolo Sarpi. </s>

<s>&mdash; XV. Dell'Accademia <lb/>de'Lincei e di Francesco Bacone </s></p><p type="main">

<s><emph type="center"/>I.<emph.end type="center"/></s></p><p type="main">

<s>Accingendoci alla difficile opera di narrare le recondite vie, <lb/>proseguendo le quali l'uomo giunse all'acquisto delle cognizioni <lb/>sperimentali, sentiamo vivo il bisogno di risalir col nostro pensiero <lb/>a ricercar, nel nostro intelletto, l'origine prima, e, se tanto avre&shy;<lb/>mo di forza, il principio delle nostre cognizioni e le fonti naturali. </s>

<s><lb/>Questa ultima espressione valga intanto ad assicurare i lettori che <lb/>non saremo per condurli attraverso agli aerei campi de'metafisici, <lb/>n&egrave; per menarli in giro fra le combattenti schiere de'filosofi spe&shy;<lb/>culativi, ma, indossata oramai la divisa di storici del Metodo spe&shy;<lb/>rimentale applicato all'acquisto delle verit&agrave; naturali, dello stesso <pb xlink:href="020/01/045.jpg" pagenum="26"/>metodo sperimentale ci serviremo pure a investigar l'origine prima <lb/>e i progressi delle nostre cognizioni. </s></p><p type="main">

<s>I fantastici sistemi dei cos&igrave; detti Ontologi, e lo sbagliato me&shy;<lb/>todo dei sensisti loro oppositori, sembr&ograve;, nel secolo scorso, che <lb/>fossero consigliati di posar l'armi e di ridursi al silenzio da quel <lb/>Tommaso Reid, capo della scuola scozzese, che primo insegn&ograve; d'in&shy;<lb/>vestigar le leggi dell'intelletto dietro la diligente osservazione dei <lb/>fatti. </s>

<s>I pedagogisti poi, nel presente secolo, seppero sapientemente <lb/>trar pro da que'nuovi e fecondi ammaestramenti, e la Necker e il <lb/>Guillemon, nello studio amoroso della vita degl'infanti, raccolsero <lb/>cos&igrave; gran numero di osservazioni, che si pot&egrave;, dietro ad esse, sco&shy;<lb/>prire sperimentalmente la legge, secondo la quale, in principio, <lb/>l'uomo ama ed intende. </s>

<s>Proseguendo questo stesso metodo d'in&shy;<lb/>terne osservazioni Alessandro Manzoni, nel suo Romanzo, ci dipinse <lb/>tale qual'&egrave; il cuore dell'uomo, e Raffaello Lambruschini, ne'suoi <lb/>Dialoghi, espose eloquentemente agli italiani la detta legge del&shy;<lb/>l'amare e dell'intendere, scoperta cos&igrave; dietro a quelle nuove espe&shy;<lb/>rienze. </s></p><p type="main">

<s>Una delle principali e delle pi&ugrave; importanti conclusioni, che de&shy;<lb/>rivarono immediatamente da cos&igrave; fatte esperienze, fu che le prime <lb/>notizie delle cose hanno origine nell'intelletto da tutt'altra fonte <lb/>che dai sensi. </s>

<s>Il Reid argomenta, dietro accurate osservazioni, che <lb/>il primo oggetto conosciuto dal bambino &egrave; la sua propria madre, <lb/>e ch'ei la conosce e intende non altrimenti, che come un essere <lb/>intelligente ed amante. </s>

<s>Il primo linguaggio, secondo il filosofo scoz&shy;<lb/>zese, con cui la donna si comunica col portato delle sue viscere, <lb/>&egrave; il linguaggio dell'amore: importantissima scoperta, per la quale <lb/>si rende solubile il problema dell'origine del linguaggio stesso, es&shy;<lb/>sendo incongruente quel che pareva ammettersi, prima, da'filosofi, <lb/>che cio&egrave; si possa la parola insegnare per mezzo della parola. </s></p><p type="main">

<s>Da queste nuove dottrine, e da quelle, altres&igrave;, pi&ugrave; antiche, <lb/>scende un'altra importantissima conclusione, ed &egrave; la necessit&agrave; delle <lb/>tradizioni. </s>

<s>La fiaccola dell'intelletto par che imiti strettamente <lb/>l'esempio di queste nostre fiaccole artificiali, le quali non si accen&shy;<lb/>dono, se non che nella luce di un altra fiaccola, che a loro si ap&shy;<lb/>pressi. </s>

<s>Le osservazioni dei nuovi filosofi o psicologi sperimentali, <lb/>non che la storia dell'umano incivilimento, dimostrano quella ne&shy;<lb/>cessit&agrave; degl'insegnamenti tradizionali con evidentissima prova di <lb/>fatti. </s>

<s>&Egrave; perci&ograve; la necessit&agrave; delle tradizioni una legge, alla quale <lb/>inesorabilmente soggiace ogni svolgimento dell'umano pensiero, <pb xlink:href="020/01/046.jpg" pagenum="27"/>cosicch&egrave; l'ammettere l'esistenza d'ingegni veramente <emph type="italics"/>creatori<emph.end type="italics"/> &egrave; un <lb/>errore in filosofia, com'&egrave; un errore in fisica l'ammettere la gene&shy;<lb/>razione spontanea. </s></p><p type="main">

<s>Non dissimuliamo che la legge ora annunziata viene a porre <lb/>in grande impaccio i neoterici, i quali ammettono che, cos&igrave; nel&shy;<lb/>l'ordine cosmico, come nell'intellettuale, tutto sia giunto per s&egrave; <lb/>al presente grado di perfezione, per via di successivo, graduale e <lb/>spontaneo svolgimento. </s>

<s>Che se, non potendo conciliare i fatti con <lb/>la necessit&agrave; che li governa, alcuni altri sapienti ammettono un prin&shy;<lb/>cipio prestabilito all'ordine mondano e una primitiva civilt&agrave; rive&shy;<lb/>lata, hanno tuttavia diritto di credere nell'esistenza di quel primo <lb/>Architettore del mondo e di quel primo Maestro dell'uomo, che <lb/>essi appellano col nome di Dio, infintanto che gli scienziati novelli <lb/>non sieno giunti a dimostrar con pi&ugrave; di evidenza le misteriose ori&shy;<lb/>gini della civilt&agrave; e del cosmo. </s></p><p type="main">

<s>Dell'ammettere l'esistenza di quel primo Maestro, che per mezzo <lb/>della madre si comunica al bambinello, sentirono vivamente il bi&shy;<lb/>sogno, cos&igrave; il Reid, come i pedagogisti inspir&agrave;ti agl'insegnamenti <lb/>di lui, e negando, anzi, come si disse, che le prime notizie appro&shy;<lb/>dino alla mente per via dei sensi, non dubitarono d'affermar che <lb/>l'intelletto s'apre alla luce di Dio, come s'apre il fiore al primo <lb/>raggio di sole. </s>

<s>Dio che &egrave; luce, l'intelletto umano, il qual &egrave; l'occhio <lb/>che vede, gli esseri creati, che s'irraggiano di quella divina luce <lb/>e la riflettono al veggente, formano il soggetto e compongono l'en&shy;<lb/>ciclopedia di tutto il nostro sapere. </s>

<s>Lasciando ad altri di trattar la <lb/>scienza che riguarda il primo e il secondo di que'soggetti, quel che <lb/>importa a noi non &egrave; propriamente che il terzo, le prime notizie del <lb/>quale vediamo com'incominci ad apprenderle il bambino. </s></p><p type="main">

<s>O rivolga egli spontanea l'attenzione agli oggetti circostanti, o <lb/>alcuno, vezzeggiandolo, glieli presenti innanzi e lo inviti e lo alletti <lb/>a riguardarli, lo vediamo immobile e contemplativo tener fissi gli <lb/>occhi in que'medesimi oggetti. </s>

<s>Dop'esser rimasto alquanto in quella <lb/>estatica contemplazione, il bambinello, che non ha ancora incomin&shy;<lb/>ciato a pigliar possesso del mondo, se l'oggetto in qualche modo <lb/>lo alletta, colla bellezza delle forme esteriori e del colore, stende <lb/>innanzi il braccio e apre la mano per prendersi quell'oggetto, ma <lb/>&egrave; notabile ch'ei non si sporga punto per aggiungerlo, cosicch&egrave; se <lb/>gli riesce pi&ugrave; lontano di quel che bisogni per toccarlo, mena a vuoto <lb/>a tresca per l'aria con quel braccio teso e con quella manina aperta. </s>

<s><lb/>Questo &egrave; segno che egli non ha ancora imparato a misurar la di-<pb xlink:href="020/01/047.jpg" pagenum="28"/>stanza, e che i visibili oggetti gli si presentano come se fossero <lb/>dipinti sopra una tela calatagli innanzi agli occhi. </s>

<s>Di qui viene <lb/>ad acquistare la prima idea dello spazio superficiale, circoscritto <lb/>all'intorno dal pi&ugrave; semplice e regolare de'perimetri, il cerchio. </s>

<s><lb/>L'esercizio poi e l'uso che egli arcanamente impara a fare degli <lb/>argomenti della parallasse, lo rendono accorto dell'altra dimensione <lb/>dello spazio, della profondit&agrave;, cosicch&egrave; dalla superficie passa ad <lb/>acquistar l'idea del solido e dalla nozione del cerchio passa a quella <lb/>dell'emisfero. </s>

<s>&Egrave; la geometria dunque la prima scienza che l'uomo <lb/>impara, e la prima arte che lo guida in acquistar le prime notizie <lb/>del mondo creato. </s>

<s>Quel bambinello intanto, il quale aveva poco pi&ugrave; <lb/>che quaranta giorni, ha passato gi&agrave; dell'et&agrave; sua il primo anno. </s>

<s>Tor&shy;<lb/>niamo ad osservarne gli atti, e a veder quali novit&agrave; presentano i <lb/>suoi costumi. </s>

<s>Non &egrave; pi&ugrave;, com'allora, estatico e contemplativo: ei <lb/>si vede anzi vivameute commosso alle impressioni che fanno sopra <lb/>lui gli oggetti esteriori, e alcuni lo impauriscono, per cui rifugge <lb/>strillando da loro, e altri lo allettano, e sorridendo si sporge per <lb/>averli, e avutili, desiderosamente, gli stringe e se ne impossessa. </s>

<s><lb/>Non si contenta pi&ugrave; di contemplare con gli occhi l'esteriore appa&shy;<lb/>renza di quelle cose, ma le stringe fortemente fra le sue mani, per <lb/>renderne pi&ugrave; intimo e pi&ugrave; squisito il contatto, le lacera quasi vo&shy;<lb/>lesse penetrare a veder quel che v'&egrave; dentro e sotto esse nascosto, <lb/>e tanta avidit&agrave; ha di compenetrarsi con quelli oggetti, che tutto <lb/>vorrebbe cacciar dentro alla sua bocca. </s>

<s>L'altro passo dunque che <lb/>fa l'uomo, per pigliar pieno possesso del mondo &egrave; quello dell'eser&shy;<lb/>cizio de'sensi e dell'arte dell'esperienza. </s></p><p type="main">

<s>Ma prima di giungere a questo secondo passo, proseguendo per <lb/>la dirittura di quella via, che conduce l'uomo alle prime notizie del <lb/>mondo creato, percorre una via traversa, e si direbbe perci&ograve; che <lb/>delira. </s>

<s>Alla serena contemplazione che abbiamo ammirata dianzi, <lb/>prima che il bambino passi a quella sua vivacit&agrave; di atti per cui il <lb/>mondo si assoggetta a'suoi sensi; succede una specie d'irrequie&shy;<lb/>tezza, la quale non &egrave; poi altro se non che l'effetto di un segreto <lb/>orgoglioso delirio. </s>

<s>Il bambino &egrave; irrequieto, perch&egrave; vorrebbe che il <lb/>mondo procedesse a modo suo, e prima d'imparar che il mondo <lb/>si governa con leggi sue proprie, vorrebbe esser egli il legislatore <lb/>del mondo. </s></p><p type="main">

<s>La storia, che abbiamo cos&igrave; a chiare note letta, in quel micro&shy;<lb/>cosmo intellettuale, &egrave; la storia che si verifica nella vita dell'uomo <lb/>adulto, anzi &egrave; la storia dell'origine e de'progressi che conducono <pb xlink:href="020/01/048.jpg" pagenum="29"/>tutto un popolo incivilito all'acquisto delle verit&agrave; naturali. </s>

<s>Dalle <lb/>osservazioni fatte sopra il bambino risulta che, degli oggetti creati, <lb/>prima acquista notizia della forma, per mezzo della geometria, e <lb/>poi della materia per mezzo dei sensi e dell'esperienza. </s>

<s>Cos&igrave;, basta <lb/>appena volgere un occhiata fuggitiva alla storia della scienza, per <lb/>vedere che, in ogni periodo d'incivilimento prima sono state a fio&shy;<lb/>rire le scienze matematiche e poi le fisiche. </s>

<s>Nelle stesse scienze <lb/>fisiche matematiche si verifica pure la medesima legge. </s>

<s>L'astrono&shy;<lb/>mia matematica, per esempio, precede all'astronomia fisica, e alla <lb/>meccanica razionale precede la scienza astratta del moto. </s>

<s>La Fisica, <lb/>la Chimica e la Geologia, il soggetto delle quali &egrave; pi&ugrave; remoto dalla <lb/>forma e pi&ugrave; prossimo che mai alla materia, sono scienze apparite <lb/>via via in questi tre ultimi secoli. </s></p><p type="main">

<s>Tali semplicissime osservazioni storiche dei fatti bastano a per&shy;<lb/>suader chiunque che la legge, la quale governa lo svolgimento in&shy;<lb/>tellettuale dell'individuo, &egrave; la legge stessa che governa gli svolgi&shy;<lb/>menti intellettuali di un intero popolo incivilito. </s>

<s>Ma perch&egrave; ogni <lb/>popolo incivilito riconosce qualche suo insigne capo-scuola e mae&shy;<lb/>stro, ne'libri scritti dal quale si compendia e si ritrae quasi in <lb/>ispecchio tutto ci&ograve; che di vero ha quello stesso popolo imparato e <lb/>scoperto; noi vogliamo dimostrare ai nostri lettori come la divisata <lb/>legge storica si verifichi negli insegnamenti lasciati dai due pi&ugrave; <lb/>insigni capo scuola e maestri dello scientifico incivilimento, Platone, <lb/>e Aristotile. </s></p><p type="main">

<s><emph type="center"/>II.<emph.end type="center"/></s></p><p type="main">

<s>Che la civilt&agrave; e la cultura, nella nostra Italia approdasse dalla <lb/>contigua Grecia &egrave; cosa tanto nota, e cos&igrave; naturale, che la Geografia <lb/>stessa quasi serve di prova. </s>

<s>La forma peninsulare delle due terre, <lb/>su cui il sole con temperata letizia dolcemente sorride, e il mare, <lb/>che largamente le bagna e ne'golfi e ne'seni e negl'ismi stretta&shy;<lb/>mente le abbraccia, furono forse le cause principali, per cui lo spi&shy;<lb/>rito delle pi&ugrave; antiche civilt&agrave; asiatiche e affricane liberamente alitasse <lb/>per le loro felici contrade. </s>

<s>Uno de'primi e principali uomini, che <lb/>la face della scienza accendesse sulle rive del Nilo, e la trasportasse <lb/>con la scrittura di libri eloquentissimi di Grecia in Italia, fu quel <pb xlink:href="020/01/049.jpg" pagenum="30"/>Platone che del nostro scientifico progresso si dee da noi riguardare <lb/>qual efficacissimo promotore e maestro. </s></p><p type="main">

<s>Socrate gli educ&ograve;, nella patria Atene, il cuore e la mente. </s>

<s>E <lb/>chi era Socrate? </s>

<s>&mdash; Io son figlio, ei risponde nel Teeteto appresso <lb/>lo stesso Platone, di una valentissima levatrice, che si chiama Fe&shy;<lb/>narete, e anch'io, come lei, esercito questa medesima arte. </s>

<s>Infe&shy;<lb/>condo per me stesso, ostetrico i parti altrui e gli educo alla luce. </s>

<s>&mdash; <lb/>Se gli avesse alcuno domandato quali precetti gli fosse bisognato <lb/>osservare per conseguire la moralit&agrave; e la scienza, compendiosamente <lb/>rispondeva <emph type="italics"/>conosci te stesso.<emph.end type="italics"/> Platone dunque si fece imitatore fede&shy;<lb/>lissimo di quell'arte ostetrica, e osservatore diligentissimo di quel <lb/>precetto, per cui, sebbene sia sembrato che il Reid e i pedagogisti <lb/>moderni abbiano ora nuovamente e per i primi introdotto nella <lb/>psicologia il metodo dell'osservazione sperimentale; quel metodo <lb/>nonostante &egrave; antichissimo, e quasi un eco del socratico responso. </s>

<s><lb/>Non riuscir&agrave; perci&ograve; cosa di meraviglia a nessuno quella, che saremo <lb/>ora per profferire, ed &egrave; questa: che le platoniche dottrine sono una <lb/>viva espressione e uno splendidissimo dramma, che rappresenta in <lb/>atto lo stato e le condizioni della mente dell'uomo, nel primo <lb/>acquisto delle verit&agrave; naturali, secondo ci risultava dall'osservare i <lb/>fatti del bambinello, che di poco ha passato quaranta giorni. </s>

<s>Anche <lb/>egli infatti, Platone, ammette che primo maestro all'uomo non &egrave; <lb/>che Dio, l'esistenza del quale, nel libro decimo delle Leggi, &egrave; di&shy;<lb/>mostrata con tutti quegli argomenti, a cui sembra che poco di pi&ugrave; <lb/>nuovo e di pi&ugrave; bello abbian saputo aggiungervi i teologi moderni. </s>

<s><lb/>Della necessit&agrave; delle tradizioni poi &egrave; cos&igrave; ben persuaso il filosofo <lb/>greco, da doversi anzi dire che tutto il suo sistema &egrave; informato di <lb/>quel principio. </s>

<s>E in vero non vuol nemmeno che le notizie acqui&shy;<lb/>state si appellino col nome di <emph type="italics"/>scienza,<emph.end type="italics"/> ma piuttosto con quello di <lb/><emph type="italics"/>reminiscenza,<emph.end type="italics"/> come se l'intelletto le avesse prima possedute, attin&shy;<lb/>gendole direttamente dal cielo, e poi avesse via via occasione di <lb/>ridursele alla memoria. </s></p><p type="main">

<s>Chi poi volesse vedere in Platone eloquentemente rappresen&shy;<lb/>tate queste stesse dottrine sotto forma di apologo, legga il principio <lb/>del libro VII <emph type="italics"/>Dello Stato,<emph.end type="italics"/> dove l'intelletto che apprende le cose, <lb/>per mezzo dei sensi, vien rassomigliato a un uomo, che vede appa&shy;<lb/>rire e sparire gli oggetti per le loro ombre proiettate sul fondo di <lb/>una spelonca, dentro alla quale sia condannato a starsene rinchiuso <lb/>per tutto il tempo della sua vita. </s></p><p type="main">

<s>La filosofia insomma del grande Ateniese, fa, secondo noi, esat-<pb xlink:href="020/01/050.jpg" pagenum="31"/>tissimo ritratto di quella contemplazione estatica, nella quale ve&shy;<lb/>diamo assorto il bambino, quando prima incomincia a pigliar notizia <lb/>del mondo. </s>

<s>La geometria delle forme, secondo si disse, &egrave; il primo <lb/>oggetto e la prima arte della sua cognizione. </s>

<s>Ed ecco infatti il Filo&shy;<lb/>sofo greco proclamare l'utilit&agrave; grandissima e l'importanza, che per <lb/>l'acquisto delle verit&agrave; naturali ha la geometria e la scienza dei nu&shy;<lb/>meri in generale. </s>

<s>&ldquo; Questa scienza, dice egli nell'Epinomide, mentre <lb/>&egrave; la sorgente di tutti i beni non &egrave; sorgente di verun male, il che <lb/>&egrave; facile a provare. </s>

<s>Il numero non entra per nulla in ogni specie <lb/>di metro, dove non regna n&egrave; regime, n&egrave; ordine, n&egrave; figura, n&egrave; mi&shy;<lb/>sura, n&egrave; armonia: in una parola, in tutto ci&ograve; che partecipa a qualche <lb/>male. </s>

<s>&rdquo; Cos&igrave; par si voglia insinuar dall'Autore, che la Matematica <lb/>&egrave; tutto insieme principio di moralit&agrave;, e fondamento di scienza. </s></p><p type="main">

<s>A Platone succede immediatamente nell'ufficio di maestro e <lb/>nell'autorit&agrave; di capo scuola, cos&igrave; del greco, come dell'italico incivi&shy;<lb/>limento, un altr'uomo, che sebben sia discepolo di lui e per di&shy;<lb/>ciassett'anni frequenti l'Accademia, professa nulladimeno dottrine <lb/>tutt'affatto diverse. </s>

<s>Questo &egrave; il famosissimo Aristotile, il quale, nato <lb/>in Stagira, bench&egrave; di sangue greco, piccola e ignobile citt&agrave; della <lb/>Tracia, risente alquanto della ruvidezza natia e della operosit&agrave; del <lb/>montanaro. </s>

<s>Ma quella sua ruvidezza e quella operosit&agrave;, che f&agrave; cos&igrave; <lb/>risentito contrasto colla placida contemplazione platonica, &egrave; la rap&shy;<lb/>presentazione pi&ugrave; viva di quella irrequietezza che vedemmo succe&shy;<lb/>dere alle estatiche e serene centemplazioni del bambinello. </s>

<s>Noi giu&shy;<lb/>dicammo quella addirittura una fase morbosa, per la quale passa <lb/>la mente nel progredire all'acquisto delle verit&agrave; naturali, e la qua&shy;<lb/>lificammo per un delirio. </s>

<s>N&egrave; dubitiamo ora di qualificar similmente <lb/>per una fase morbosa e per un delirio la filosofia aristotelica, la <lb/>quale rappresenta per noi quel secondo stato, in cui si trova nella <lb/>successiva conquista delle cognizioni, la mente dell'uomo. </s></p><p type="main">

<s>Per qual motivo l'irrequietezza che si osserva nel bambino, e <lb/>che vien rappresentata dalla operosit&agrave; aristotelica, fu qualificata da <lb/>noi per un delirio? </s>

<s>Perch&egrave; cos&igrave; il bambino come Aristotile vor&shy;<lb/>rebbero che la Natura si governasse a loro proprio modo, e preten&shy;<lb/>derebbero d'imporre piuttosto che assoggettarsi alle leggi di lei. </s>

<s><lb/>Tale appunto &egrave; il carattere, di che s'impronta la filosofia naturale <lb/>del famosissimo Stagirita. </s>

<s>Mentre che Platone conclude le prime <lb/>e pi&ugrave; universali notizie delle cose derivare da tutt'altra fonte che <lb/>dai sensi, esce invece il discepolo a sentenziare nulla essere nel&shy;<lb/>l'intelletto che non sia prima stato nel senso, per cui se il primo <pb xlink:href="020/01/051.jpg" pagenum="32"/>insegna il particolare essere incluso nell'universale che lo precede, <lb/>l'altro, tutt'al contrario, asserisce che il particolare precede all'uni&shy;<lb/>versale, il concetto di cui la mente sa formarselo da s&egrave; stessa. </s>

<s>Ecco <lb/>quello che si pu&ograve; chiamare un indiarsi della ragione, la quale, come <lb/>fecondamente produce i concetti universali, per opera dialettica del&shy;<lb/>l'astrazione; cos&igrave; d&agrave; leggi ai particolari via via che occorra di rico&shy;<lb/>noscerli per la percezione de'sensi. </s>

<s>Di qui &egrave; che il Filosofo intende <lb/>com'ad opera principale, a dar regole e a istituir precetti intorno <lb/>alla dialettica e alla rettorica, ed &egrave; riconosciuto da tutti per primo <lb/>inventore argutissimo del sillogismo. </s>

<s>Che cos'&egrave; alle mani di Ari&shy;<lb/>stotile il sillogismo? </s>

<s>&Egrave; un artificio lusinghiero, per cui si d&agrave; a cre&shy;<lb/>dere con gran facilit&agrave; che la conclusione derivi dalle premesse, non <lb/>per necessit&agrave; logica, ma per sola opera dialettica della mente ragio&shy;<lb/>natrice. </s>

<s>Perci&ograve; egli, nell'investigare le cause de'fatti naturali aborre <lb/>dalla troppa semplicit&agrave;: quelle cause non son vere, per lui, se non <lb/>quando sieno state ritrovate da'pi&ugrave; sottili e artificiosi ragionamenti. </s>

<s><lb/>Com'esempio di ci&ograve; pu&ograve; citarsi, dal libro delle Meteore, e da quello <lb/>dei Problemi, ci&ograve; che dice dell'origine delle fontane, ripudiando <lb/>l'opinion di coloro che riconoscevano quelle segrete origini dalli <lb/>stillicidii de'monti imbevuti delle nevi squagliate e delle pioggie <lb/>invernali. </s>

<s>Attendendo poi bene, si trova non aver quel ripudio, nella <lb/>mente del Filosofo, altro motivo, se non per esser quella opinione <lb/>troppo ovvia e facile a ritrovar dagl'ingegni volgari. </s>

<s>Chi svolge i <lb/>libri dello Stagirita s'abbatte frequentemente a trovar di ci&ograve; simili <lb/>altri esempi. </s></p><p type="main">

<s>Platone aveva bandita aspra guerra ai sofisti, e nell'Eutidemo <lb/>svela i pi&ugrave; intricati laberinti dei loro errori e gli sconfigge coll'arguta <lb/>ironia, che dardeggia dalle semichiuse labbra di Socrate. </s>

<s>Nel Pro&shy;<lb/>tagora poi aveva gi&agrave; con pari arte eloquente, confutato il sensismo, <lb/>conchiudendo che, se regola del nostro conoscere sono i sensi, nulla <lb/>&egrave; pi&ugrave; nel mondo d'immutabile e di vero. </s>

<s>Ma Aristotele, bench&egrave; sia <lb/>sollecito di rimuover da s&egrave; la taccia d'essere incorso negli errori <lb/>di Protagora e di Eutidemo, &egrave; nonostante di fatto pi&ugrave; sensista del <lb/>primo e pi&ugrave; sofista del secondo, non consistendo bene spesso la sua <lb/>dialettica in altro, che in appuntar la freccia ai sofismi, ed essendo <lb/>i suoi libri fisici una continuata apoteosi dei sensi. </s>

<s>Il discepolo in&shy;<lb/>somma professa apertamente dottrine, non solo diverse, ma tutt'af&shy;<lb/>fatto contrarie a quelle del suo maestro, e, in ordine al proposito <lb/>nostro, il succedersi dell'una scuola all'altra, segna nella storia <lb/>delle scienze sperimentali, un notabilissimo regresso. </s></p><pb xlink:href="020/01/052.jpg" pagenum="33"/><p type="main">

<s>Dalle due antiche scuole di Grecia derivarono gli Accademici <lb/>e i Peripatetici, i quali, da quasi ventitr&egrave; secoli, hanno tenuto il <lb/>campo della scienza in Europa, essendo mirabilmente le loro arche <lb/>rimaste galleggianti sui flutti agitatori di tanti popoli fra s&egrave; divisi <lb/>per variet&agrave; di climi e di costumi, per comuni sventure e per con&shy;<lb/>trarie passioni. </s>

<s>Dietro ci&ograve;, si comprender&agrave; assai facilmente come <lb/>debba la Storia del metodo sperimentale incominciare dalla institu&shy;<lb/>zione dell'Accademia, a cui segue immediatamente quella del Pe&shy;<lb/>ripato, considerando con brevit&agrave;, ma colla diligenza che ci sar&agrave; pos&shy;<lb/>sibile, ci&ograve; che conferissero quelle due scuole a dar gli inizii e a <lb/>promuovere in qualche modo quegli stessi metodi sperimentali. </s></p><p type="main">

<s><emph type="center"/>III.<emph.end type="center"/></s></p><p type="main">

<s>Prendano dunque le mosse queste nostre considerazioni dal <lb/>sistema filosofico di Platone, brevemente aggirandoci, insiem coi <lb/>nostri lettori, per i lussureggianti orti di Academo. </s>

<s>La lussuria degli <lb/>alberi, che ombreggiano i viali, fa senza dubbio ritratto della esu&shy;<lb/>berante facondia di colui che, avvolto nel pallio filosofale, parla alla <lb/>numerosa e scelta giovent&ugrave; ateniese tratta ad udirlo. </s>

<s>Ma il refri&shy;<lb/>gerio che vien da una tal lussuria di fronde a'cocenti ardori del <lb/>sole e il grato odore che esala dai dolci pomi maturi, persuadono <lb/>facilmente ognuno che ivi l'utilit&agrave; va congiunta al diletto. </s></p><p type="main">

<s>La qualit&agrave; principale e il carattere distintivo di quella platonica <lb/>scuola, gi&agrave; dicemmo essere la contemplazione. </s>

<s>&ldquo; La verit&agrave;, va tut&shy;<lb/>tavia ripetendo il gran maestro, non si pu&ograve; conoscere da noi quaggi&ugrave; <lb/>in terra, se non isforzandoci a rompere i vincoli che ci tengono <lb/>strinti e avviluppati nel corpo. </s>

<s>&rdquo; &Egrave; questa del gran filosofo, senza <lb/>dubbio, una esagerazione, anzi diciamolo addirittura un errore, per&shy;<lb/>ch&egrave; se l'uomo &egrave; naturalmente composto di anima e di corpo, deb&shy;<lb/>bono ambedue insieme, con provvida legge concorrere a un mede&shy;<lb/>simo ufficio: onde, la conseguenza che immediatamente deriva dalle <lb/>platoniche dottrine sarebbe che l'acquisto della scienza non &egrave; per <lb/>noi che un inutile desiderio. </s>

<s>Dall'altra parte poi, se il corpo &egrave; di im&shy;<lb/>paccio continuo all'anima, e se non sono i sensi altro che una fonte <lb/>perenne d'inganni, &egrave; chiaro che non utile alla ricerca della verit&agrave;, <lb/>ma sommamente dannosa, dovrebbe, secondo il sistema filosofico di <lb/>Platone, riuscir qualunque istituzione del metodo sperimentale. </s></p><pb xlink:href="020/01/053.jpg" pagenum="34"/><p type="main">

<s>Questa infatti &egrave; la conclusione a cui giunge il discepolo di quel <lb/>Socrate, che fu udito dire pi&ugrave; volte aver nello studio della storia <lb/>naturale trovato piuttosto da perdere che da guadagnare. </s>

<s>Cos&igrave; stando <lb/>appunto le cose, quale speranza possiamo dunque aver noi di veder <lb/>la Filosofia sperimentale spuntar su dalle verdeggianti aiuole del&shy;<lb/>l'Accademia? </s>

<s>I nostri lettori perci&ograve;, che attendono curiosi la risposta, <lb/>dovrebbero rammemorarsi come noi dicemmo, ne'principii del no&shy;<lb/>stro Discorso, che la filosofia platonica rappresenta quel primo stato <lb/>della mente dell'uomo, in cui, degli oggetti creati ella apprende <lb/>le prime notizie, piuttosto per via delle forme geometriche, che per <lb/>la materiale impressione del senso. </s>

<s>D'onde si pu&ograve; comprendere, <lb/>che se quella Filosofia non introduce nell'arte sperimentale, e anzi <lb/>la ripudia reputandola non solo inutile, ma, che &egrave; peggio, dannosa; <lb/>vi sostituisce per&ograve; un'altr'arte che la precede e che &egrave;, o dovrebbe <lb/>essere il fondamento di quella, essendo certissima legge che gli og&shy;<lb/>getti si conoscono prima per la forma e poi per materia. </s>

<s>Platone <lb/>insomma non introduce nella fisica, ma in quella che pu&ograve; chiamarsi <lb/>matematica della fisica. </s></p><p type="main">

<s>Egli &egrave; infatti, il filosofo atienese, gran maestro di Geometria. </s>

<s><lb/>Fiorirono nella scuola di lui Aristeo, Eudossio, Mnecmo e Dinostrato, <lb/>i quali riuscirono a dar la soluzione de'due pi&ugrave; difficili problemi, <lb/>che fossero proposti alla geometria: la duplicazione del cubo e la <lb/>trisezione dell'angolo. </s>

<s>Alla scuola di Platone appartengono pure i <lb/>due pi&ugrave; insigni maestri che abbia avuto, e in cos&igrave; lungo decorrere <lb/>di secoli, abbia tuttavia la scienza, Euclide e Archimede. </s></p><p type="main">

<s>Tratteniamoci a cons&iuml;derare un poco il sublime aspetto e la <lb/>maest&agrave; veneranda del nostro Siracusano. </s>

<s>Egli &egrave; la prima splendida <lb/>apparizione, e la rappresentazione pi&ugrave; viva di ci&ograve; che fosse l'arte <lb/>sperimentale in Italia nel III secolo prima di Ges&ugrave; Cristo. </s>

<s>Il disco&shy;<lb/>pritore del furto dell'oro nella corona del r&egrave; Gerone, l'incendiatore <lb/>delle navi di Marco Marcello, il taumaturgo, che per mezzo di una <lb/>semplicissima leva si d&agrave; vanto di poter commuovere la terra e il cielo, <lb/>passa per il primo gran fisico sperimentale che abbia avuto l'Italia, <lb/>e perci&ograve; non sembra che possa essere uscito Archimede dalla scuola <lb/>matematica di Platone. </s></p><p type="main">

<s>Considerando per&ograve; pi&ugrave; sottilmente, si trover&agrave; che l'abito del <lb/>Siracusano non differisce in nulla dal pallio del filosofo atienese. </s>

<s><lb/>Cos&igrave; l'uno come l'altro tengon dietro alle forme dei corpi, e non <lb/>vogliono avvilir l'ingegno dietro alla loro materia. </s>

<s>Questa nota del&shy;<lb/>l'ingegno archimedeo &egrave; posta in piena evidenza da ci&ograve; che ne scrive <pb xlink:href="020/01/054.jpg" pagenum="35"/>Plutarco nella vita di Marco Marcello, dove dice appunto che Ar&shy;<lb/>chimede non faceva nessun conto delle sue fisiche e meccaniche <lb/>invenzioni, non essendo esse altro che <emph type="italics"/>giochi di geometria, ne'quali <lb/>s'era abbattuto trattenendovisi attorno per suo passatempo.<emph.end type="italics"/> Ecco il <lb/>carattere distintivo della fisica platonica, ecco in qual concetto si <lb/>tenevan dagli Accademici i fatti naturali: giochi di geometria e pas&shy;<lb/>satempi. </s>

<s>Di un tal suggello &egrave; profondamente impresso il primo Trat&shy;<lb/>tato di fisica tramandatoci dall'antichit&agrave;, gli <emph type="italics"/>Spiritali<emph.end type="italics"/> di Herone <lb/>alessandrino, discepolo di Archimede: trattato, dove l'ingegno <lb/>scherza intorno ai moti prodotti principalmente dal dilatarsi e dal <lb/>condensarsi dell'aria, come Ctesibio, altro discepolo dello stesso <lb/>Archimede, scherza intorno a simili altri moti prodotti dall'acqua. </s></p><p type="main">

<s>Ma esistono del gran discepolo di Platone, onore di Siracusa <lb/>e d'Italia, e son pervenuti infino a noi, attraverso alle vicende dei <lb/>secoli, due Trattati insigni, quello degli <emph type="italics"/>Equiponderanti<emph.end type="italics"/> e quello dei <lb/><emph type="italics"/>Galleggianti,<emph.end type="italics"/> dove si pongono cos&igrave; saldi fondamenti scienziali alla <lb/>Statica e alla Idrostatica, da non passar per la mente a nessuno che <lb/>possa altri qualificarli per giochi di geometria o per fisici passatempi. </s>

<s><lb/>Verissimo: ma essi pure, que'due Trattati del matematico siracu&shy;<lb/>sano, presentano il carattere proprio e distintivo della Filosofia na&shy;<lb/>turale di Platone, che &egrave; quello di astrarre dalle propriet&agrave; naturali <lb/>dei corpi, per trattenersi a contemplare le propriet&agrave; matematiche e <lb/>geometriche delle loro forme. </s>

<s>La leva archimedea infatti, sul prin&shy;<lb/>cipio della quale &egrave; fondata tutta la Statica, non &egrave; una verga solida, <lb/>ma una linea geometrica, e la potenza e la resistenza son forze che <lb/>sembrano esser messe in atto piuttosto da spiriti incorporei, che da <lb/>materie solide e ponderanti. </s>

<s>Similmente l'umido delle archimedee <lb/>idrostatiche immersioni &egrave; un liquido che non esiste in natura, ma <lb/>nelle mentali astrazioni del filosofo, il qual suppone che le molecole <lb/>rasentino le pareti de'vasi e fluiscano le une attorno alle altre senza <lb/>patirvi la minima resistenza, a quel modo che un punto genera una <lb/>linea geometrica liberamente fluendo nello spazio. </s>

<s>Quel flusso geo&shy;<lb/>metrico &egrave; moto, e anzi al moto di un punto che genera una linea, <lb/>al moto di una linea che genera una superficie, e al moto di una <lb/>superficie che genera un solido, si riduce il concetto genetico della <lb/>Geometria, che giusto, nel risalire alle sue pi&ugrave; sublimi alture, prende <lb/>per suo proprio e particolare il titolo di <emph type="italics"/>Flussioni.<emph.end type="italics"/> Non fa perci&ograve; <lb/>maraviglia che uscissero dalla scuola di Platone i due pi&ugrave; insigni <lb/>maestri della scienza del moto Archimede e Galileo. </s></p><p type="main">

<s>Ma per non prevenire i tempi moderni, soffermiamoci breve-<pb xlink:href="020/01/055.jpg" pagenum="36"/>mente a considerare in Archimede e nella sua scuola quali sieno <lb/>le note proprie e distintive della Filosofia naturale derivata dall'Ac&shy;<lb/>cademia. </s>

<s>Fedele agli insegnamenti di Platone, essa contempla nella <lb/>natura le forme geometriche, e dilettandosene sublimemente, d&agrave; <lb/>mirabili impulsi da progredire non a sola la Geometria pura, ma <lb/>alla Geometria applicata al moto dei gravi, degli astri, della luce e <lb/>de'suoni. </s>

<s>La Meccanica, l'Astronomia, l'Ottica, la Musica e simili <lb/>altre discipline e arti, in quanto si riducono a simmetria di linee <lb/>o ad armonia di numeri, son frutti allegati nel fiore degli orti Ac&shy;<lb/>cademici. </s>

<s>L'altro aspetto poi sotto cui si presenta la natura, nel <lb/>rivelarsi per l'organo dei sensi, perciocch&egrave; questi sono ingannevoli, <lb/>si riguardan da quella filosofia non altrimenti che quali scherzi im&shy;<lb/>meritevoli affatto della seria attenzion de'filosofi. </s>

<s>Per i platonici <lb/>insomma la Filosofia sperimentale, o la natura che ne forma il sog&shy;<lb/>getto, nient'altro si &egrave; che, o una lasciva fanciulla che scherza, o una <lb/>paurosa maga che incanta. </s>

<s>E in fatti tutti i libri di fisica scritti <lb/>dagli autori di quella scuola si vedon portare scritto in fronte il <lb/>titolo o di <emph type="italics"/>Magia naturale<emph.end type="italics"/> o di <emph type="italics"/>Spettacoli maravigliosi della natura.<emph.end type="italics"/></s></p><p type="main">

<s>Ma quale Filosofia sperimentale poteva derivar mai dal Peri&shy;<lb/>pato? </s>

<s>Attendiamo bene al principio che informa quella scuola. </s>

<s>Gi&agrave; <lb/>noi lo mostrammo apertamente pi&ugrave; sopra, e dicemmo consistere <lb/>quel principio nel far dipendere dalla nostra ragione le leggi che <lb/>governano la Natura. </s>

<s>In conseguenza di ci&ograve;, l'esperienza &egrave; inutile, <lb/>e la ragione legislatrice e signora non ha bisogno di travagliarsi <lb/>servilmente a osservare e a cimentare i fatti naturali. </s>

<s>A che dal&shy;<lb/>l'altra parte mostrarsi bisognosi d'inventare e di fabbricare stru&shy;<lb/>menti da rendere pi&ugrave; squisito l'uso dei sensi? </s>

<s>Alla ragione basta <lb/>quel poco che i sensi stessi possono porgerle, in qualunque maniera <lb/>sia fatto: al resto ella supplisce bene da s&egrave; medesima, senz'altro <lb/>estrinseco aiuto. </s></p><p type="main">

<s>Quali potevano essere insomma i frutti di cos&igrave; fatte dottrine? </s>

<s><lb/>Quelli, che si possono aspettar da un albero in una opaca e neb&shy;<lb/>biosa valle, senza alcuna posa combattuta dai venti. </s>

<s>Il Peripato perci&ograve; <lb/>dee essere necessariamente infecondo, chiuso, e quasi diremmo in&shy;<lb/>crisalidato nella propria ragione, e combattuto dai venti dell'orgo&shy;<lb/>glio. </s>

<s>Eppure &egrave; stato scritto da alcuni che Aristotile &egrave; gran maestro <lb/>di fisici sperimenti, per cui egli incarna le astratte speculazioni, e <lb/>colorisce i disegni aerei di Platone. </s>

<s>Magnificano costoro la Storia <lb/>degli animali del filosofo di Stagira, e la vorrebbero proporre come <lb/>esempio di diligentissime osservazioni de'fatti naturali. </s>

<s>Ma, se bene <pb xlink:href="020/01/056.jpg" pagenum="37"/>si bada, si vedr&agrave; che l'osservazione di Aristotile &egrave; affatto superfi&shy;<lb/>ciale: &egrave; quella stessa che non isfugge a nessuno, il quale apre gli <lb/>occhi a guardare le esteriori apparenze dei corpi. </s>

<s>Quando per&ograve; si <lb/>tratta di entrare addentro alla natura delle cose, l'autore incespica <lb/>e rimane intrigato in gravissimi errori, come per esempio nel caso <lb/>di determinare il modo dell'incesso de'quadrupedi e del risolvere <lb/>molte altre simili questioni di meccanica animale. </s>

<s>Del resto, anco <lb/>in quella Storia, il filosofo rivela il suo proprio genio, e diciamo <lb/>cos&igrave;, la sua propria ambizione, qual era quella di dar anima alla <lb/>natura col suo proprio discorso, lusingandosi quasi d'esserne il <lb/>Creatore, nell'atto che ne divisava le propriet&agrave; e ne annoverava le <lb/>specie. </s>

<s>Egli &egrave;, ricordiamocene, n&ograve; nella sola storia naturale ma, in <lb/>ogni scibile, il Maestro delle <emph type="italics"/>Categorie.<emph.end type="italics"/></s></p><p type="main">

<s>Chi volesse poi formarsi una pi&ugrave; giusta idea di quel genio <lb/>aristotelico; e volesse anche meglio persuadersi della falsit&agrave; dell'as&shy;<lb/>serto riferito di sopra, che cio&egrave; sia il Filosofo di Stagira gran maestro <lb/>di fisici sperimenti; non ha a far altro che svolgerne i <emph type="italics"/>Problemi<emph.end type="italics"/><lb/>per tutte quelle XXXVIII sezioni in cui l'Autore gli volle distri&shy;<lb/>buiti. </s>

<s>Essi comprendono tutta intera l'enciclopedia della scienza <lb/>naturale a quei tempi, e s'intende di dare a quel modo le risposte <lb/>pi&ugrave; sincere alle varie domande che si posson far dai curiosi. </s></p><p type="main">

<s>Non men falso poi reputiamo l'altro asserto pur di sopra no&shy;<lb/>tato, che cio&egrave; Aristotile compia le dottrine del suo Maestro. </s>

<s>Fra'due <lb/>filosofi &egrave; cos&igrave; aperto il dissidio, che &egrave; impossibile trovar ordine e <lb/>modo da ricongiungerli insieme. </s>

<s>Pur nonostante &egrave; vero che in al&shy;<lb/>cuni punti si riscontrano, ma per&ograve; si riscontrano a quel modo che <lb/>avvien delle vie tortuose che s'intersecano e procedono per qualche <lb/>tratto con le diritte rendendo pi&ugrave; che mai per&ograve; intralciato il viaggio. </s>

<s><lb/>S'incontrano senza dubbio ambedue i Filosofi greci in questo, in <lb/>recidere cio&egrave; gli stami ai progressi dell'arte sperimentale, renden&shy;<lb/>dola l'uno impossibile e l'altro inutile. </s>

<s>All'impossibilit&agrave; riducesi <lb/>evidentemente da Platone, insegnando che i sensi non rappresentano <lb/>all'anima altro che larve fuggitive ed inganni, e si riduce ad una <lb/>inutilit&agrave; per Aristotile, il quale professa che al difetto dei sensi pu&ograve; <lb/>supplire, per s&egrave; medesima, la ragione. </s>

<s>Cos&igrave; &egrave; che se, per gli Acca&shy;<lb/>demici, la Filosofia naturale &egrave; un ludibrio spettacoloso, per i Peri&shy;<lb/>patetici non &egrave; altro pi&ugrave; che una sottile esercitazion<gap/> d'ingegno. </s>

<s><lb/>D'ond'&egrave; che gli spettacoli della Natura andando bene spesso, da'loro <lb/>autori, accompagnati dalle sottigliezze della Dialettica, non &egrave; facile <lb/>a discerner se uno de'cos&igrave; fatti libri appartiene all'una o all'altra <pb xlink:href="020/01/057.jpg" pagenum="38"/>scuola, rimanendo a distinguerli questa sola infausta qualit&agrave;, che &egrave; <lb/>del vedervi costantemente i fatti naturali accomodati a secondare <lb/>la fantasia. </s></p><p type="main">

<s>Alla scuola platonica per&ograve; rimane incontrastabile il merito di <lb/>aver suggerita la prima arte di decifrare il libro della Natura, per <lb/>mezzo della Geometria, mentre alla Aristotelica non riman forse altro <lb/>vanto da quello in fuori d'aver rivolti gl'ingegni a facilitar le re&shy;<lb/>gole del calcolo numerico, intorno a che principalmente si distin&shy;<lb/>sero gli arabi. </s>

<s>L'Algebra &egrave; senza dubbio un frutto del Peripato, <lb/>come la Geometria &egrave; un frutto dell'Accademia. </s>

<s>Che se, avuto ri&shy;<lb/>guardo all'utilit&agrave; e alla eccellenza delle due discipline, si vorr&agrave; <lb/>decidere che i meriti sono uguali, avuto riguardo all'applicabilit&agrave; <lb/>delle stesse due discipline all'interpetrazion de'fatti naturali, si vedr&agrave; <lb/>che, mentre la Geometria &egrave; ala da sollevar la mente sublime alla <lb/>contemplazione del mondo, l'Algebra non &egrave; che strumento da fa&shy;<lb/>cilitare alcune delle pi&ugrave; faticose esercitazioni del nostro ingegno. </s>

<s><lb/>Tale forse non &egrave; l'ufficio dell'Algebra in s&egrave;, ma &egrave; pure l'ufficio a <lb/>cui venne rivolta dal Peripato, al quale parve che il fare scaturire <lb/>una conclusione dal meccanico operar sulle cifre, fosse un nuovo e <lb/>lusinghiero argomento, di quella potenza dell'ingegno, con che dal <lb/>sillogismo facevasi scaturire, quasi creazion della mente, la verit&agrave; <lb/>e la certezza di tutte quante le cose. </s>

<s>Perci&ograve;, mentre la Geometria <lb/>&egrave; rimasta sempre nella sua incorruttibile dignit&agrave;, l'Algebra s'&egrave; ve&shy;<lb/>duta degenerar talvolta negli abusi e ne'vizii della Dialettica. </s></p><p type="main">

<s><emph type="center"/>IV.<emph.end type="center"/></s></p><p type="main">

<s>Dalle due scuole di Platone e di Aristotile, o come si voglia <lb/>dire altrimenti, dall'Accademia e dal Peripato, derivarono le tradi&shy;<lb/>zioni della scienza e dell'arte, che ridussero in istato di civilt&agrave; le <lb/>nazioni europee e principalmente la nostra Italia. </s>

<s>L'impulso che <lb/>venne alle menti e agli animi da quelle dottrine, fu cos&igrave; potente, <lb/>che, mirabile a dirsi, dura tuttavia dopo un s&igrave; lungo decorrere di <lb/>secoli. </s>

<s>Tu<gap/> le variet&agrave; dei sistemi, che hanno tenuto, e tengono <lb/>fra s&egrave; divisi gl'ingegni speculativi, tutte le variet&agrave; dei gusti seguite <lb/>e manifestate in cos&igrave; varie maniere dalle opere degli artisti, si po&shy;<lb/>trebbero con gran facilit&agrave; ridurre a due tipi, in uno dei quali si <pb xlink:href="020/01/058.jpg" pagenum="39"/>vedrebbe impresso il sigillo del Peripato, e nell'altro quello del&shy;<lb/>l'Accademia. </s></p><p type="main">

<s>Delle due influenti scuole prima a introdursi in Italia e di li <lb/>per tutta l'Europa, fu la Platonica. </s>

<s>Le tradizioni pitagoriche dovet&shy;<lb/>tero, senza dubbio, concorrere a tal preferenza, ma ben pi&ugrave; facil&shy;<lb/>mente vi concorsero l'indole e il genio scientifico dei Romani <lb/>scolpitamente rappresentato da Cicerone. </s>

<s>Basta leggere il Trattato <lb/><emph type="italics"/>Delle Leggi<emph.end type="italics"/> e il libro dell'<emph type="italics"/>Oratore<emph.end type="italics"/> del filosofo romano, per ricono&shy;<lb/>scervi l'inspirazione diretta e immediata del Trattato delle Leggi e <lb/>del Fedro del filosofo greco. </s>

<s>La politica e la morale erano princi&shy;<lb/>palmente le due scienze, che premeva di coltivare a quel popolo, <lb/>il quale deve alla disciplina degli animi, da cui provennero i sa&shy;<lb/>pienti ordinamenti civili, la sua propria grandezza. </s>

<s>Dedito alla vita <lb/>attiva, piuttosto che alla contemplativa, della Geometria non si cur&ograve; <lb/>gran fatto. </s>

<s>Nella filosofia naturale per&ograve; fece quell'operoso popolo <lb/>romano di notabili progressi, intanto che, a qualche concetto che <lb/>si rivela dai versi di Lucrezio Caro, all'invenzione di alcuni stru&shy;<lb/>menti descritti da Vitruvio, a parecchie questioni risolute da Seneca, <lb/>e a certe teorie intravedute da Frontino, si riappiccano propriamente <lb/>le tradizioni intercise del risorto metodo sperimentale. </s>

<s>&Egrave; per&ograve; vero <lb/>che una tal messe di fisiche verit&agrave; non fu e non poteva esser rac&shy;<lb/>colta dagli orti dell'Accademia: essa fu, come si vedr&agrave; meglio tra <lb/>poco in altri esempi, frutto di una sapienza che non sarebbe po&shy;<lb/>tuta derivar da nessuna scuola. </s></p><p type="main">

<s>L'istituzione del Cristianesimo, dopo i tempi di Augusto, rin&shy;<lb/>novell&ograve; la vita del popolo romano, ma in questa profonda innova&shy;<lb/>zione una cosa rimane immutabile, l'impero di Roma, che dalle <lb/>mani della Politica passa a quelle della Religione. </s>

<s>Roma &egrave; ancora, <lb/>passato lo splendore dei Cesari, e forse con pi&ugrave; vivo senso di prima, <lb/>capo e cuore del mondo. </s>

<s>Da essa fluisce la civilt&agrave; come sangue <lb/>dalla grande arteria, e ad essa, come per condotto di vene, conti&shy;<lb/>nuamente ritorna. </s>

<s>A Cicerone sottentrano, nell'ufficio di oratori, <lb/>Minuzio Felice, Basilio Magno, Agostino, i quali o sien nati sul <lb/>Tevere, o sui lidi dell'Ellesponto, o non lungi dalle rive del Nilo, <lb/>son tutti pure, in una mente e in un cuore, ugualmente romani. </s>

<s><lb/>La nuova arte oratoria per&ograve; &egrave; varia, perch&egrave; varii ne sono i fini, ma <lb/>non per questo manco nobili e generose ne sono le intenzioni. </s>

<s>Essi <lb/>vogliono persuadere agli adoratori de'falsi d&egrave;i l'esistenza di un Dio <lb/>unico, Creatore e Conservatore del mondo, e sentono che il vero <lb/>modo a illuminar quelle menti &egrave; di accender ne'loro cuori il calor <pb xlink:href="020/01/059.jpg" pagenum="40"/>dell'affetto. </s>

<s>Essi perci&ograve; eleggono, non argomenti sottili, ma bellezze <lb/>d'immagini, e fanno uso, piuttosto che dell'arguzie della Dialettica, <lb/>de'fiori della Poesia. </s>

<s>Platone veniva cos&igrave; naturalmente a presentarsi <lb/>maestro e a porgersi imitabile esempio alla nuova eloquenza cri&shy;<lb/>stiana, e Minuzio Felice, nell'<emph type="italics"/>Ottavio,<emph.end type="italics"/> lo imita perfino nelle forme <lb/>esteriori del dialogo, e Basilio Magno nell'<emph type="italics"/>Esaemerone<emph.end type="italics"/> risale con <lb/>sublime ala platonica, dalle pittoresche bellezze della Natura infino <lb/>al trono di Dio, mentre S. </s>

<s>Agostino nelle sue <emph type="italics"/>Confessioni,<emph.end type="italics"/> scrutando <lb/>le pi&ugrave; profonde latebre del proprio cuore, mette in pratica il pre&shy;<lb/>cetto socratico del Conosci te stesso. </s></p><p type="main">

<s>Per tali spiracoli e per tal magistero, venne a introdursi la <lb/>Filosofia di Platone in mezzo alla nuova civilt&agrave; cristiana. </s>

<s>Ma la <lb/>Filosofia di Aristotile vi s'introdusse molto pi&ugrave; tardi, e per un ma&shy;<lb/>gistero tanto diverso, quanto esser pu&ograve; diversa, dalla toga magnifica <lb/>di un romano, la cappa voluttuosa di un arabo. </s>

<s>Averrois &egrave; pro&shy;<lb/>priamente colui, che si d&agrave; all'opera di tradurre i libri dello Sta&shy;<lb/>girita, e d'illustrarli col suo commento, diffondendone le dottrine <lb/>fra la sua gente, che, sebbene abbia invasa e siasi per nuova patria <lb/>usurpata la Spagna, serba nostante impresse nell'ingegno le mono&shy;<lb/>tone solitudini delle lande affricane, e nel cuore, gli alidori di quelle <lb/>arene, che gli avi avean calcate largamente col piede. </s>

<s>Quel maestro, <lb/>che insegnava a ridur tutto a regola di compasso, e dagli ammaestra&shy;<lb/>menti del quale si concludeva cos&igrave; facilmente la libert&agrave; del poter <lb/>governare s&egrave; stesso e la natura a proprio talento, non poteva non <lb/>piacere a quegli uomini, tutti dediti a riconoscere freddamente e a <lb/>noverar gli oggetti, che pi&ugrave; fanno impressione e pi&ugrave; dilettano i <lb/>sensi. </s></p><p type="main">

<s>Sotto le larghe pieghe della bianca cappa dell'arabo, veniva <lb/>cos&igrave; dunque Aristotile a introdursi in mezzo alla societ&agrave; cristiana. </s>

<s><lb/>Ma come poteva quella Filosofia accomodarsi ai precetti del Van&shy;<lb/>gelo, o come poteva quell'alidor di numeri scritti nel fango, andare <lb/>a genio a un popolo che sospirava per sua patria il cielo immen&shy;<lb/>surabile eterno? </s>

<s>Pi&ugrave; volte infatti Concilii, presieduti dagli stessi <lb/>Pontefici romani, dannarono la lettura de'libri aristotelici, ma pur <lb/>poco stette che Aristotile stesso, quasi per incantesimo, si trov&ograve; <lb/>spogliato della cappa dell'arabo e rivestito della tonaca del frate, <lb/>dall'alhambra, mirabilmente trapassando al convento. </s></p><p type="main">

<s>Era gi&agrave; incominciato il tempo delle eresie, per cui, piuttosto <lb/>che badare a insinuare la verit&agrave;, si sentiva il bisogno di confutare <lb/>l'errore. </s>

<s>Per confutarlo conveniva servirsi delle armi medesime <pb xlink:href="020/01/060.jpg" pagenum="41"/>degli oppositori, le quali consistevano nella Dialettica, e nel far uso <lb/>degli argomenti della ragione contro i dommi inconcussi della fede. </s></p><p type="main">

<s>L'eloquenza platonica perci&ograve; de'primi Padri della Chiesa do&shy;<lb/>vette cedere alle acute sillogistiche argomentazioni de'novelli Dottori, <lb/>e a far l'ufficio del monachismo sottentrarono gli Ordini regolari. </s>

<s><lb/>Alle orazioni e alle omelie meditate lungo le rive di un fiume, o <lb/>all'ombra di un palmeto, e recitate poi dal pergamo al popolo cri&shy;<lb/>stiano, succedono le aride disputazioni teologiche, scritte fra il tanfo <lb/>di una cella e diffuse per innumerevoli altre celle o a viva voce o <lb/>per copie manoscritte. </s>

<s>Il primo che pensi di raccogliere quelle <lb/>sparse disputazioni, e di ordinarle insieme in una <emph type="italics"/>Somma teologica,<emph.end type="italics"/><lb/>&egrave; Alessandro di Hales, a cui poco dopo tien dietro Alberto Magno, <lb/>maestro a quel Tommaso d'Aquino, grande istitutore della Teologia <lb/>scolastica. </s>

<s>Narrano i biografi di lui, e si va ripetendo fra gli aned&shy;<lb/>doti della sua vita, com'egli, sedendo a mensa con gli altri frati, <lb/>rimanesse una volta senza nulla curarsi del cibo, e stato alquanto <lb/>cos&igrave; cogitabondo, uscisse poi con incomposta esultanza a dire: <emph type="italics"/>l'ho <lb/>trovato, l'ho trovato.<emph.end type="italics"/> E che cosa aveva egli trovato? </s>

<s>Nient'altro se <lb/>non un argomento da risolvere una sottile questione teologica, che <lb/>egli era andato inutilmente cercando per lungo tempo. </s>

<s>Il fatto non <lb/>pu&ograve; non richiamare alla memoria quell'altro simile e ben pi&ugrave; fa&shy;<lb/>moso aneddoto, che si racconta della vita di Archimede, per cui <lb/>manifesto risulta da tal confronto che il Filosofo di Aquino, in <lb/>investigar gli argomenti di ragione prosegue con quello stesso ar&shy;<lb/>dore di metodo, che il matematico di Siracusa in investigar le verit&agrave; <lb/>pi&ugrave; recondite della Natura. </s>

<s>Ed ecco posto cos&igrave; in piena evidenza <lb/>il carattere proprio della filosofia scolastica. </s></p><p type="main">

<s>Non &egrave; del presente nostro proposito il dar giudizio di S. </s>

<s>Tom&shy;<lb/>maso come filosofo speculativo e come metafisico: intorno a ci&ograve;, <lb/>egli ha senza dubbio meriti insigni, confermatigli dall'ossequioso <lb/>consenso di cinque secoli. </s>

<s>Il giudizio nostro solamente versa circa <lb/>la Filosofia naturale, che il padre della Scolastica attinse tutta da <lb/>Aristotile, insegnando a legger piuttosto ne'libri di lui, che in quelli <lb/>della Natura. </s>

<s>Ecco da che venerande mani furono nel secolo XIII <lb/>instaurati in Italia gl'idoli aristotelici. </s>

<s>E qual maraviglia &egrave; che la <lb/>turba ossequiosa vi s'inchinasse ciecamente a offerirgli incensi? </s></p><p type="main">

<s>La grande autorit&agrave; di S. </s>

<s>Tommaso fu senza dubbio una delle <lb/>cause principali, per cui il Peripato nuovo venne a costituirsi, ma <lb/>non fu l'unica. </s>

<s>Le molte altre che vi concorsero, e non punto meno <lb/>efficaci, si potrebbero ritrovar facilmente in quella comodit&agrave;, che <pb xlink:href="020/01/061.jpg" pagenum="42"/>veniva dal supplir con la lettura di un libro, al faticoso esercizio <lb/>dello sperimentare. </s>

<s>Un tal metodo doveva riuscir tanto meglio ac&shy;<lb/>comodato alla qualit&agrave; degli abitatori del chiostro, in quanto che, <lb/>non avendo essi occasione di travagliarsi col mondo per provvedere <lb/>alle necessit&agrave; e sodisfare ai piaceri della vita, si potevano lusingar <lb/>facilmente che le leggi naturali si potessero indurre con la stessa <lb/>facilit&agrave;, con cui si conducevano i sillogismi. </s>

<s>Di qui &egrave; che un prin&shy;<lb/>cipio di vanit&agrave; e di orgoglio doveva essere il carattere proprio di <lb/>quella filosofia, vanit&agrave; ed orgoglio che divamparono putidamente, <lb/>quando, per le opposizioni, il Peripato si ristrinse insieme congiu&shy;<lb/>rato in una setta. </s>

<s>Ch&igrave; ripensi ora che i chiostri erano i soli asili <lb/>in cui si rifugiava e da cui si diffondeva la scienza, comprender&agrave; <lb/>quali dovessero essere le condizioni delle scienze naturali per tutto <lb/>il tempo che domin&ograve; quella scuola. </s>

<s>Condizioni generali per&ograve;, per&shy;<lb/>ch&egrave; non manc&ograve; fin d'allora chi si volse a filosofar, piuttosto che <lb/>sui libri, sull'osservazione e sull'esperienza de'fatti, come si vedr&agrave; <lb/>seguitando il nostro Discorso. </s></p><p type="main">

<s><emph type="center"/>V.<emph.end type="center"/></s></p><p type="main">

<s>Perch&egrave; sempre i primi impulsi, che rivolsero la mente del&shy;<lb/>l'uomo alla investigazione dei fatti naturali, derivarono dai bisogni <lb/>e dal desiderio di conseguire alcuni util&inodot; fini, e perch&egrave; per primi e <lb/>principali fra questi utili e questi bisogni venivano a rappresentarsi <lb/>quelli, che concernevano il modo di conservare la sanit&agrave; o di re&shy;<lb/>staurarla con l'arte, se in qualunque modo fosse stata perduta; si <lb/>comprender&agrave; facilmente com'uno de'primi oggetti, a cui si rivolse <lb/>la Filosofia naturale, dovess'essere la Medicina: Platone e Aristotile <lb/>non avevano trascurato di farsi maestri anco di quest'arte, e come <lb/>nelle discipline speculative, cos&igrave; in questa tennero divise, nella di&shy;<lb/>versit&agrave; de'principii informativi e delle opinioni, le loro scuole: In&shy;<lb/>stauratosi il nuovo Peripato non sembra che si sapesse trovare alla <lb/>cultura delle scienze fisiche miglior campo di quello della stessa <lb/>Medicina. </s>

<s>Ruggero Bacone, Alberto Magno, Raimondo Lullo perdono <lb/>il loro tempo e consumano il loro inchiostro in formular ricette e <lb/>in trovar segreti da guarire ogni sorta di mali. </s>

<s>Pi&ugrave; tardi, anco <lb/>quando l'Anatomia e la Fisica presentivano cos&igrave; d'appresso l'isti-<pb xlink:href="020/01/062.jpg" pagenum="43"/>tuzione galileiana, il Falloppio e il Porta, per tacere di altri minori, <lb/>rinnovellarono l'esempio di que'ricettarii e lusingarono i semplici <lb/>con que'loro segreti. </s></p><p type="main">

<s>Apriamo per curiosit&agrave; i libri <emph type="italics"/>De secretis mulierum<emph.end type="italics"/> di Alberto <lb/>Magno, o quell'altro di Raimondo Lullo, che messer Pietro Lauro <lb/>volle rendere popolare, traducendolo dal latino, e facendolo stam&shy;<lb/>pare in Venezia nel 1567 dai fratelli Sessa. </s>

<s>Il libro del Lullo, a <lb/>cui erasi dato nel frontespizio il titolo di filosofo acutissimo e di <lb/>celebre medico, &egrave; rivolto a trovar nientedimeno che la <emph type="italics"/>quintessenza,<emph.end type="italics"/><lb/>e il libro di Alberto a svelare i segreti della generazione. </s>

<s>I libri <lb/>di quegli antichi dottori, bench&egrave; fossero conosciuti a pi&ugrave; prove non <lb/>contenere che falsit&agrave;, allettarono nonostante cos&igrave; i medici e gli <lb/>scrittori del secolo XVI, che il gran Falloppio non isdegna abbas&shy;<lb/>sarsi a impugnar la penna, per iscrivere un libro di <emph type="italics"/>Secreti diversi <lb/>e miracolosi.<emph.end type="italics"/> Forse, per onor del grand'uomo potrebbesi ragione&shy;<lb/>volmente congetturare che il libro fosse compilato dai discepoli e <lb/>spacciato sotto il suo nome, la qual congettura verrebbe confermata <lb/>dal veder che la stampa eseguita in Venezia nel 1582 occorse di&shy;<lb/>ciannove anni dopo la morte dell'Autore. </s>

<s>In qualunque modo, non <lb/>cessa perci&ograve; quella Falloppiana raccolta di Segreti diversi di esser <lb/>documento che attesti da quali umili principii avesse origine la <lb/>scienza naturale, in quel secolo, che immediatamente precede a <lb/>quello di Galileo. </s>

<s>E perch&egrave; pi&ugrave; efficace riesca una tale testimonianza, <lb/>leggansi i soggetti che si trattano ne'tre libri, ne'quali la Raccolta <lb/>stessa dal compilatore venne divisa. </s>

<s>Nel primo si tratta il modo <lb/>di fare diversi olii, cerotti, unguenti, unzioni, elettuarii, pillole e <lb/>infiniti altri medicamenti. </s>

<s>Nel secondo s'insegna a fare alcune sorti <lb/>di vini e acque molto salutifere, e nel terzo si contengono alcuni <lb/>importanti segreti di Alchimia ed alcuni altri segreti dilettevoli e <lb/>curiosi. </s></p><p type="main">

<s>Parecchi di que'segreti, che si leggono nella Raccolta, la quale <lb/>v&agrave; sotto il nome del Falloppio, piacquero a quell'altro infaticabile <lb/>compilatore di ricette altrui e di altrui invenzioni, che fu Giovan <lb/>Batista Porta, ed ei ne infarc&igrave; que'suoi quattro libri <emph type="italics"/>De'miracoli <lb/>e maravigliosi effetti della Natura.<emph.end type="italics"/></s></p><p type="main">

<s>Ma che cosa sono in sostanza questi segreti proposti, e questi <lb/>miracolosi effetti della Natura, spacciati dagli Autori di cos&igrave; fatti <lb/>libri? </s>

<s>Niente altro, si capir&agrave; bene, che voci di cerretani. </s>

<s>Il prin&shy;<lb/>cipio peripatetico, che cio&egrave; la Natura si governa colla ragione del&shy;<lb/>l'uomo e si muove, nel produrre i suoi effetti, a seconda dell'umano <pb xlink:href="020/01/063.jpg" pagenum="44"/>discorso, vedesi vivamente in que'libri, meglio che altrove, incar&shy;<lb/>nato, apparendo chiaro per essi come nell'arte medica non ci ha <lb/>a che far nulla l'esperienza, e tutto consiste nello stillarsi il cer&shy;<lb/>vello, e nel fare a chi sa meglio comporre insieme una strana ri&shy;<lb/>cetta. </s>

<s>La sottilit&agrave; dialettica, o per dir meglio, la pi&ugrave; sfrenata fantasia <lb/>del medico &egrave; quella che dee operar nel malato ogni efficacia. </s></p><p type="main">

<s>Che il Peripato nuovo fosse principalmente rivolto alla Medi&shy;<lb/>cina, lo attestano tre de'pi&ugrave; famosi fra i cultori delle scienze na&shy;<lb/>turali, nel secolo XVI, Girolamo Fracastoro, Girolamo Cardano, e <lb/>Andrea Cesalpino, tutti e tre medici celebratissimi di professione. </s>

<s><lb/>Il primo di questi, veronese di patria e vissuto dal 1483 al 1553, <lb/>se si vuol pareggiar nell'ingegno agli altri due, non &egrave; dubbio per&ograve; <lb/>ch'egli &egrave; d'assai superiore a loro nella dignit&agrave; della vita. </s>

<s>Che il <lb/>Fracastoro appartenga alla scuola peripatetica, a noi par cosa certa <lb/>bench'egli molte volte dimostri di saper pensare da s&egrave;, cercando <lb/>cose nuove e tentando d'investigare alcune delle verit&agrave; naturali, <lb/>non colla dialettica aristotelica, ma per la via diretta dell'esperienza. </s></p><p type="main">

<s>Che il celebre veronese avesse veramente saputo pensare anche <lb/>da s&egrave;, lo dice quel libro ch'egli scrisse degli <emph type="italics"/>Omocentrici,<emph.end type="italics"/> dedicato <lb/>a quello stesso Paolo III, a cui il Copernico dedic&ograve; la grande opera <lb/><emph type="italics"/>De revolutionibus.<emph.end type="italics"/> Il nostro italiano, volere o no, rinnovellatore del&shy;<lb/>l'opinione di Eudossio, &egrave; il pi&ugrave; prossimo precursore dell'insigne <lb/>astronomo prussiano, restauratore del sistema di Aristarco. </s>

<s>Egli in&shy;<lb/>tende principalmente a dimostrar che i pianeti non fanno le loro <lb/>rivoluzioni per cerchi eccentrici, ma per omocentrici e argutamente <lb/>interpetra alcune anomalie de'loro moti mostrando, per esempio, <lb/>che il moto obliquo del sole per l'ecclettica risulta dalla composi&shy;<lb/>zione de'due moti in longitudine e in latitudine, e affermando la <lb/>variet&agrave; dell'inclinazione dell'ecclittica stessa esser costante, e dover <lb/>perci&ograve; un giorno tornare a confondersi con l'equatore, sicch&egrave; par <lb/>voglia cos&igrave; convalidare, coi placiti della scienza, una volgare opi&shy;<lb/>nione degli antichi egiziani. </s></p><p type="main">

<s>Nel libro degli <emph type="italics"/>Omocentrici,<emph.end type="italics"/> o consapevole o no, vi si sente <lb/>aliar lo spirito di Platone, ed &egrave; forse perci&ograve; che il Fracastoro mo&shy;<lb/>stra di sentir dispiacere e non lascia di far qualche scusa per avere <lb/>a contradire talvolta al suo Aristotile. </s>

<s>Cos&igrave;, in sul principio del ca&shy;<lb/>pitolo sesto, riferendo l'opinion del Filosofo, conforme alla quale le <lb/>orbite dei pianeti vengono per l'attrito via via sempre pi&ugrave; indugiate <lb/>dal primo mobile, secondo che sono a lui sempre pi&ugrave; vicine, ragion <lb/>per cui tardissima &egrave; la sfera di Saturno, e velocissima quella della <pb xlink:href="020/01/064.jpg" pagenum="45"/>Luna; prima di sentenziar che una tale opinione o non &egrave; vera o <lb/>che &egrave; in contradizione con altri detti aristotelici, premette le parole: <lb/><emph type="italics"/>si licet de tanto philosopho dicere.<emph.end type="italics"/> Ritorna per&ograve; l'Autore agli os&shy;<lb/>sequi del suo maestro, ogni volta che, disceso dalle sublimit&agrave; della <lb/>Geometria platonica, viene a rasentare colle ali basse la fisica pe&shy;<lb/>ripatetica. </s></p><p type="main">

<s>Egli vuol, per esempio, nel Capitolo VIII della II

a Sezione dello <lb/>stesso libro degli <emph type="italics"/>Omocentrici,<emph.end type="italics"/> render la ragione della variet&agrave; del <lb/>diametro apparente, che presentano il Sole e la Luna, secondo che <lb/>son pi&ugrave; presso all'orizzonte o al zenit, o secondo che si trovano <lb/>nel perigeo o nell'apogeo, e crede di dover riconoscere quella ra&shy;<lb/>gione, come fece Galileo, negli effetti ottici prodotti dalla sfera va&shy;<lb/>porosa dell'aria. </s>

<s>Ma, mentre Galileo attribuisce quegli effetti alla <lb/>maggiore o minore convessit&agrave; della detta sfera, il Fracastoro invece <lb/>gli attribuiva alla maggiore o minore altezza del mezzo, professando <lb/>il principio che un diafano soprapposto a un diafano ingrandisce <lb/>sempre le specie. </s>

<s>Ora &egrave; chiaro che un tal principio derivava per <lb/>diretta via dalle fonti peripatetiche, o in altre parole non consisteva <lb/>altrimenti che in una ipotesi immaginaria, imperocch&egrave;, secondo fu <lb/>ritrovato poi dal medesimo Galileo, per esperienza, facilmente si <lb/>osserva che, soprainfondendo acqua ad acqua dentro un catino, la <lb/>moneta posata sul suo fondo non cresce nel diametro apparente, <lb/>anzi sembra talvolta qualche poco diminuire. </s></p><p type="main">

<s>Ma ci&ograve; che pi&ugrave; chiaramente dimostra non essersi il Fracastoro <lb/>potuto sottrarre ai perniciosi influssi della scuola peripatetica, &egrave; <lb/>quell'altro suo libro <emph type="italics"/>De Sympatia et anthipatia rerum,<emph.end type="italics"/> che egli <lb/>scrisse come Prodromo alla trattazione sua medica dei contagi. </s>

<s>E <lb/>a quel modo che egli attribuisce alla simpatia e alla antipatia le <lb/>cause fisiologiche e patologiche ne'morbi pestilenziali; cos&igrave; alla <lb/>simpatia e alla antipatia attribuisce pure le cause occulte delle at&shy;<lb/>trazioni elettriche e magnetiche nei fatti naturali. </s>

<s>Egli &egrave; vero, non <lb/>tralascia talvolta di ricorrere all'esperienza, per assicurarsi de'fatti <lb/>pi&ugrave; particolari di quelle attrazioni, ma com'egli mal vi riesca, si <lb/>vede nel capitolo VIII del citato libro <emph type="italics"/>De Sympathia.<emph.end type="italics"/> Il nostro me&shy;<lb/>dico veronese fu de'primi, com'avvert&igrave; nell'opera sua lo stesso Gil&shy;<lb/>berto, ad attribuire la direzione dell'ago magnetico ad alcune <lb/>montagne ferruginose, esistenti nelle regioni del polo nordico. </s>

<s>Ma <lb/>come anco questa non fosse, nella mente dell'Autore, altro che una <lb/>pura ipotesi peripatetica, o in altri termini, immaginaria, lo dimo&shy;<lb/>stra ad evidenza nel capitolo ultimo quella risposta, che ivi fa a <pb xlink:href="020/01/065.jpg" pagenum="46"/>Giovan Battista Rannusio, il quale opponeva che, se avesse fonda&shy;<lb/>mento di qualche verit&agrave; l'ipotesi del Fracastoro, si sarebbe dovuto <lb/>veder fare qualche notabile alterazione all'ago nautico, nel passar <lb/>che fanno i navigli presso all'isola dell'Elba. </s></p><p type="main">

<s>In qualunque modo per&ograve;, il Fracastoro &egrave; un ingegno serio e <lb/>se cade in errore non se ne compiace e non lo scansa, perch&egrave; non <lb/>lo conosce. </s>

<s>Non cos&igrave; pu&ograve; dirsi dell'altro medico milanese Girolamo <lb/>Cardano, che ebbe i natali in Pavia nel 1501. La lunghissima vita <lb/>protratta infino al 1596 non valse a correggerlo delle sue turpitu&shy;<lb/>dini, le quali sfacciatamente confessa al pubblico nella Autobiografia, <lb/>attribuendole a inevitabili suggestioni de'suoi Demonii. </s>

<s>Qualunque <lb/>siasi per&ograve; la moralit&agrave; de'suoi costumi, a noi non s'appartiene di <lb/>parlare che della scienza, la quale, perch&egrave; forse insozzata di fango <lb/>e rimescolata ai pi&ugrave; strani errori e alle fantasie pi&ugrave; stravaganti, &egrave; <lb/>stata, secondo noi, fin qui mal giudicata. </s>

<s>Di che si pu&ograve; fra'molti <lb/>esempi citar quello de'fuochi di S. Elmo, annoverandosi fra le <lb/>infinite stravaganze di lui quel che ne scrive nel II Libro <emph type="italics"/>De subti&shy;<lb/>litate;<emph.end type="italics"/> stravaganze che poi il Beccaria ridusse alle vere cause dei <lb/>fenomeni e degli effetti consueti d'operarsi naturalmente dall'im&shy;<lb/>provviso fulminare delle stellette o de'fuochi elettrici. (Dell'Elet&shy;<lb/>tric., Torino 1753, pag. </s>

<s>222). </s></p><p type="main">

<s>L'altro medico di professione, che qui s'interza al Fracastoro <lb/>e al Cardano &egrave; quell'Andrea Cesalpino, in cui si gloria la sua pa&shy;<lb/>tria Arezzo d'aver dato un precursore al fortunassimo Harvey. </s>

<s>Quali <lb/>meriti veramente competano al Peripatetico aretino, rispetto alla <lb/>grande scoperta della circolazione del sangue, lo vedranno i lettori <lb/>nel seguito della nostra storia, dove anche troveranno argomenti <lb/>da ammirare ci&ograve; che egli osserv&ograve; di fisiologia vegetabile, e ci&ograve; che <lb/>egli specul&ograve; per sottordinare in generi e specie la svariata famiglia <lb/>delle piante. </s>

<s>Ma pure appresso a quelle pagine, dove in tanto piena <lb/>evidenza si mette l'uso e l'ufficio naturale della vena arteriosa e <lb/>dell'arteria venosa, seguono altre pagine, dove l'Autore intende a <lb/>sostener l'opinione aristotelica dell'origine dei nervi dal cuore. </s>

<s>Si&shy;<lb/>milmente agli impulsi fisici di capillarit&agrave;, per cui la linfa ascende <lb/>dalle radici alle foglie attraverso ai vasi, fa concorrere efficacemente, <lb/>l'Autor <emph type="italics"/>De plantis,<emph.end type="italics"/> i superni influssi celesti. </s>

<s>Ma i cinque libri delle <lb/><emph type="italics"/>Peripatetiche questioni<emph.end type="italics"/> sono una tal palestra di sottigliezza d'ingegno, <lb/>che se la Natura veramente assecondasse per poco il cervello del Ce&shy;<lb/>salpino e quello di Aristotile suo maestro, il mondo, e le leggi che <lb/>lo governano, sarebbero sostanzialmente trasformate dall'esser loro. </s></p><pb xlink:href="020/01/066.jpg" pagenum="47"/><p type="main">

<s><emph type="center"/>VI.<emph.end type="center"/></s></p><p type="main">

<s>Fra'tre sopra commemorati merita particolare attenzione quel <lb/>Girolamo Cardano, di cui si disse gi&agrave;, e ora da noi si ripete, che <lb/>la scienza fu mal giudicata. </s>

<s>Egli, oppresso dalla turba dei peripa&shy;<lb/>tetici, e tante volte da loro soggiogato e ridotto alla pi&ugrave; abietta vilt&agrave; <lb/>dell'ossequio, si prova di tratto in tratto a levar alta la fronte e <lb/>declama contro l'autorit&agrave; del Maestro, contrapponendogli l'autorit&agrave; <lb/>del raziocino e della esperienza. </s></p><p type="main">

<s>Due sono principalmente i libri scritti da lui in soggetto di <lb/>scienze sperimentali: quello <emph type="italics"/>De subtilitate<emph.end type="italics"/> e l'altro <emph type="italics"/>De rerum va&shy;<lb/>rietate.<emph.end type="italics"/> Il primo &egrave; una storia generale de'principii delle cose natu&shy;<lb/>rali e artificiali; il secondo si direbbe il <emph type="italics"/>Cosmo scientifico<emph.end type="italics"/> di quei <lb/>tempi. </s>

<s>Dedicando nel 1552 a Ferdinando Gonzaga, Principe di Mol&shy;<lb/>fetta, i libri XXI <emph type="italics"/>De subtilitate,<emph.end type="italics"/> scrive che molte delle cose ivi dette <lb/>e delle pi&ugrave; importanti, le ha dovute nasconder <emph type="italics"/>sub cortice,<emph.end type="italics"/> in grazia <lb/>de'suoi contradittori, i quali, son sue parole, non hanno altro ar&shy;<lb/>gomento da appormi da quello in fuori, <emph type="italics"/>quod ab Aristotile dissen&shy;<lb/>tire videar. </s>

<s>Nam adeo humanum genus sibi iam prurit, ut malint <lb/>a veritate a sensu ab experimento a rationeque, denique ab omnibus <lb/>quam ab auctoritate viri discedere.<emph.end type="italics"/> E prosegue a dir di non sapere <lb/>intendere come mai si lodi Galeno, che tante volte contradice ad <lb/>Aristotele, e si condanni lui, che se ne dilunga una o due volte, e <lb/>dove vi sia costretto da chiarissime ragioni e da certissimi espe&shy;<lb/>rimenti. </s></p><p type="main">

<s>I XVII libri <emph type="italics"/>De rerum varietate<emph.end type="italics"/> furono nel 1556 dedicati a <lb/>Cristoforo Madruzio, e nella lettera dedicatoria inveisce l'Autore <lb/>contro quei pervicaci, i quali presumono il pelago immenso della <lb/>divina Sapienza restringer a capir nell'umano vasello aristotelico <lb/><emph type="italics"/>exiguo nec satis integro,<emph.end type="italics"/> ed esclama contro costoro: <emph type="italics"/>Nonne stultos <lb/>si credant, invidos si non credant eos existimare oportet?<emph.end type="italics"/></s></p><p type="main">

<s>Nel cap. </s>

<s>XXXVIII del libro VII di questa medesima opera, a <lb/>proposito del celebre Trattato <emph type="italics"/>De piscibus<emph.end type="italics"/> del Rondelezio, il Cardano <lb/>scriveva le notabilissime parole seguenti: &ldquo; Laudo equidem quod <lb/>propter veritatem Aristotilem et Galenum relinquat: quod autem <lb/>veritatem relinquat ut ab Aristotile vel alio discedat, non laudo. <pb xlink:href="020/01/067.jpg" pagenum="48"/>Multi enim conantur nos imitari, qui ab Aristotile dissentimus <lb/>uno vel altero loco, sed non ita dissentimus, ut experimentum <lb/>et validas rationes illi opponamus. </s>

<s>Atque id non ut illum oppu&shy;<lb/>gnemus, sed quoniam ars ipsa, quae innumera docet artificia, <lb/>aliter constitui non poterat, adeo ut si ipse reviviscat Aristotiles, <lb/>vel in nostram opinionem venturus sit, vel saltem non aegre la&shy;<lb/>turus quod tot evidentibus rationibus, ob tantamque utilitatem <lb/>ab eo discesserim &rdquo; (Basilaee 1581, pag. </s>

<s>381). E chi &egrave; mai che, <lb/>leggendo queste parole, non ricorra col pensiero e non torni colla <lb/>memoria a quell'altre simili scritte da Galileo: &ldquo; Avete voi forse <lb/>dubbio che, quando Aristotele vedesse le novit&agrave; scoperte in cielo, <lb/>e'non fosse per mutare opinione e per emendare i suoi libri? </s>

<s>&rdquo; <lb/>(Alb. </s>

<s>I, 124). Il Cardano dunque professa principii simili a quelli <lb/>di Galileo, e ha sotto le zolle inculte seminati i medesimi germi <lb/>scienziali, da cui non &egrave; possibile che non si produca, alla sua sta&shy;<lb/>gione, qualche buon frutto, e sia pure, come si vuole silvestro e <lb/>immaturo. </s>

<s>Aprendo gl'incolti rami intricati, e scoprendo le foglie <lb/>lussuriose, a chi dentro ci guardi attentamente non &egrave; difficile d'in&shy;<lb/>contrar qua e l&agrave; con l'occhio in qualcuno di questi frutti. </s></p><p type="main">

<s>Apriamo nel libro II <emph type="italics"/>De subtilitate,<emph.end type="italics"/> dove tratta degli elementi. </s>

<s><lb/>S'entra addentro a una questione di meccanica importantissima, dal <lb/>gran maestro Aristotele cos&igrave; mal definita: alla questione dei moti <lb/>violenti. </s>

<s>Dop'avere annoverate le varie sentenze degli antichi filo&shy;<lb/>sofi, il Cardano conclude: &ldquo; Sed nos magis indigemus prima, quae <lb/>est simplicissima, et etiam non tantas difficultates patitur, et cum <lb/>supponitur quod omne quod movetur ab aliquo movetur, veris&shy;<lb/>simum est sed illud quod movet est impetus acquisitus, sicut <lb/>calor in aqua &rdquo; (Lugduni 1580, pag. </s>

<s>93). </s></p><p type="main">

<s>Ecco intanto confermata, contro i perniciosi errori di Aristotile, <lb/>la verit&agrave; che il proietto non &egrave; mosso dall'aria, ma dalla virt&ugrave; del <lb/>proiciente, che gli rimane impressa come il calore nell'acqua, ed <lb/>ecco insieme, col principio d'inerzia, posti i primi fondamenti alla <lb/>Meccanica. </s>

<s>Il moto violento, prosegue a dir l'Autore, &egrave; tanto pi&ugrave; <lb/>celere quanto il proiciente si muove pi&ugrave; celermente e per pi&ugrave; lungo <lb/>spazio accompagna il proietto, e quanto &egrave; meno denso il mezzo e <lb/>il proietto stesso &egrave; pi&ugrave; acuminato. </s>

<s>La via descritta per l'aria in <lb/>principio a in fine del moto, &egrave; retta, <emph type="italics"/>sed media quasi linea quae <lb/>parabolae forma imitatur<emph.end type="italics"/> (ibi. </s>

<s>pag. </s>

<s>96). Che se a colui che ri&shy;<lb/>pensa ai progressi galileiani sembrano queste antiche tradizioni della <lb/>scienza italiana di grande importanza, d'importanza minore non <pb xlink:href="020/01/068.jpg" pagenum="49"/>giudicher&agrave; certo quel che seguita a specular l'Autore intorno ai <lb/>pendoli di varia lunghezza, e alla ragion ch'ei ne rende del veder <lb/>gravissimi corpi sospesi venir mossi quasi col soffio incantatore di <lb/>una parola. </s></p><p type="main">

<s>Ma il cap. </s>

<s>VI del I libro <emph type="italics"/>De rerum varietate,<emph.end type="italics"/> a chi ripensi che <lb/>fu scritto tanti anni prima di quello del Castelli, riesce un mara&shy;<lb/>viglioso trattatello della misura delle acque correnti. </s>

<s>La gran legge <lb/>delle quantit&agrave; proporzionali al prodotto della velocit&agrave; per la sezione, <lb/>il Cardano non la dimostra, ma la tien come un supposto; tanto a <lb/>lui, com'a tutti, par semplice e vera. &ldquo; Ut vero eam constituamus, <lb/>duo supponere necesse est: alterum quod iuxta foraminis ampli&shy;<lb/>tudinem aqua defertur; alterum quod iuxta impetum &rdquo; (pag. </s>

<s>61). </s></p><p type="main">

<s>Nel correr che fa l'acqua dentro i tubi chiusi, specialmente <lb/>se sieno pieni, osserva sagacemente il Cardano che la non &egrave; libera <lb/>nel suo moto, dovendosi tirare altr'acqua dietro, per evitare la <lb/>discontinuit&agrave;, ma giunta allo sbocco, si trova a dover ubbidire al&shy;<lb/>l'impeto di due forze, una violenta e l'altra naturale, per cui segue <lb/>una via di mezzo. </s>

<s>Chi ripensi alle difficolt&agrave; incontrate in tal pro&shy;<lb/>posito da Galileo, promosse da coloro che dicevano non esser pos&shy;<lb/>sibile che di due forze, le quali operano nello stesso tempo con <lb/>varia direzione d'impulsi, l'una non impedisca il libero esercizio <lb/>dell'altra, ammirer&agrave; il Cardano che per la intricata via della verit&agrave; <lb/>procede cos&igrave; diritto e sicuro. </s>

<s>N&egrave; l'ammirer&agrave; meno, quando pro&shy;<lb/>ponendosi di risolvere il quesito: <emph type="italics"/>cur aquae a lateribus etiam stan&shy;<lb/>tium paludum effusae per rimas tabularum impetum secum affe&shy;<lb/>rant<emph.end type="italics"/> (pag. </s>

<s>69) mostra di non aver nemmeno aombrato, non che <lb/>offeso nell'errore del Michelini, il quale verr&agrave;, dopo i tempi di Ga&shy;<lb/>lileo e del Castelli e del Torricelli, ad affermar che l'acqua non <lb/>fa impeto alcuno sopra le sponde, ma lo rivolge tutto a premere <lb/>il fondo dei vasi. </s></p><p type="main">

<s>Intin da que'tempi, notizia da non si dover trascurare nella <lb/>storia dell'Idraulica, a riconoscer la varia velocit&agrave; degli strati delle <lb/>acque correnti, si faceva uso degli <emph type="italics"/>Idrometri,<emph.end type="italics"/> e segnatamente di <lb/>quelli, dall'altra parte semplicissimi, de'quali il Cabeo si dice che <lb/>fosse il primo a far uso. </s>

<s>E giusto col <emph type="italics"/>baculo idrometrico<emph.end type="italics"/> s'era vo&shy;<lb/>luto, a tempi del Cardano, argomentar che gli strati infimi corrono <lb/>pi&ugrave; velocemente de'sommi, dal veder che l'estremit&agrave; inferiore del <lb/>baculo stesso veniva pinta in avanti. </s>

<s>Ma il Cardano, che negava il <lb/>fatto e ammetteva esser pi&ugrave; veloci di tutti gli altri, gli strati superfi&shy;<lb/>ciali, ricorre a un argomento, che ha dello strano, bench&egrave; sia per&ograve; <pb xlink:href="020/01/069.jpg" pagenum="50"/>largamente ricompensata questa stranezza da un'altra osservazione <lb/>idrometrica, che non fa qui, ma nell'altro libro <emph type="italics"/>De subtilitate.<emph.end type="italics"/></s></p><p type="main">

<s>Una tale osservazione riguarda l'equilibrio dell'acqua ne'sifoni, <lb/>e scopre un errore di coloro, i quali credono potersi per un con&shy;<lb/>dotto far tanto risalir l'acqua quanto ella &egrave; scesa. </s>

<s>Ma il vero &egrave;, dice <lb/>il Cardano, che la si riman l'acqua stessa sempre alquanto al disotto <lb/>e con tanta maggior differenza quanto la via percorsa &egrave; pi&ugrave; lunga. <lb/>&ldquo; Quanto enim longior via fuerit, eo maior differentia, iuxta alti&shy;<lb/>tudinis mensuram esse debet. </s>

<s>Hinc errores quorundam, qui ad <lb/>libramentum cum conati essent aquas deducere maximas iactu&shy;<lb/>ras impensarum susceperunt &rdquo; (pag. </s>

<s>25). Quando in Firenze, <lb/>tanti anni dopo da che furono scritte queste parole, si vollero <lb/>dalle sorgenti di Pratolino derivar l'acque ad alimentar le fon&shy;<lb/>tane di Boboli, Andrea Arrighetti teoricamente confermava gli av&shy;<lb/>vertimenti pratici del Cardano, e i fatti in quel caso sperimentati <lb/>attestarono delle verit&agrave; predicate dal fisico milanese, e dal disce&shy;<lb/>polo di Galileo. </s></p><p type="main">

<s>Ma un'altro discepolo di Galileo, Evangelista Torricelli, in fatto <lb/>della pi&ugrave; rumorosa e pi&ugrave; importante scoperta che sia stata fatta, <lb/>va a riscontrarsi colle stesse sottilit&agrave; della fisica antica. </s>

<s>Il vieto au&shy;<lb/>tore di queste <emph type="italics"/>Sottilit&agrave;<emph.end type="italics"/> non vuol sentir parlare di orrore o di fuga <lb/>del vacuo. </s>

<s>L&agrave; dove si prova a render la ragione del moto ne'sifoni <lb/>da travasare i liquidi, accenna all'aria sopraincombente che ne aiuta <lb/>quel moto, bench&egrave; sarebbe senza dubbio temerit&agrave; l'asserire che <lb/>avesse riconosciuto in quel fatto idrostatico l'intervento della pres&shy;<lb/>sione atmosferica. </s>

<s>Altrove infatti nel render la ragione del perch&egrave; <lb/>in un vaso, estratta coll'aspirazion della bocca l'aria, si veda sot&shy;<lb/>tentrare in suo luogo l'acqua, dice che la poca aria rimasta, affinch&egrave; <lb/>non diasi il vuoto, attrae l'acqua stessa di che lo Scaligero lo ri&shy;<lb/>prende con queste parole: &ldquo; Nam quare sapientiorem facis aerem <lb/>ut moveat aquam ad subeundum, aquam negligentiorem ad adim&shy;<lb/>plendum vacuum? </s>

<s>&rdquo; (De subtil. </s>

<s>Francof. </s>

<s>1592, pag. </s>

<s>58). Il Car&shy;<lb/>dano insomma non si appose al vero, ma non &egrave; piccola gloria per <lb/>lui l'aver, bench&egrave; cos&igrave; dalla lontana, aperti i chiusi e intricati sen&shy;<lb/>tieri al Torricelli, sostituendo a un nome vano un fatto. </s>

<s>Il fatto <lb/>fisico che egli sostituisce al peripatetico orrore del vacuo &egrave; che i <lb/>corpi non patiscono d'essere rarefatti, se non che dentro certi li&shy;<lb/>miti, oltrepassati i quali o si rompono o danno luogo per attrazione <lb/>a sottentrarvi altri corpi. &ldquo; Ergo in universum tres erunt motus <lb/>naturales. </s>

<s>Primus quidem ac validissimum a vacui fuga, sed ve-<pb xlink:href="020/01/070.jpg" pagenum="51"/>rius a forma elementi, cum maiorem raritatem non admittat, nec <lb/>materiae partes separari nunquam queant &rdquo; (pag. </s>

<s>17). </s></p><p type="main">

<s>Il nome di Giuseppe Scaligero &egrave; tanto strettamente connesso <lb/>con quel del Cardano, che quasi, com'&egrave; avvenuto a noi stessi di <lb/>sopra, non si pu&ograve; parlare della scienza dell'uno, senza che si vegga <lb/>intromettersi per qualche parte, e anzi irrompere con violenza in <lb/>mezzo la scienza anche dell'altro. </s>

<s>Egli infatti scrisse un libro collo <lb/>stesso titolo <emph type="italics"/>De subtilitate,<emph.end type="italics"/> a solo fine di contrapporre a quelle del <lb/>Cardano le sottigliezze sue proprie. </s>

<s>Il filosofo veronese per&ograve;, sia <lb/>scaltrezza o sia ossequio sincero, non appunta mai direttamente <lb/>l'armi del raziocinio e della esperienza contro Aristotile, che egli <lb/>appella <emph type="italics"/>humanae sapientiae parentem,<emph.end type="italics"/> ma, l&agrave; dove il testo non gli <lb/>par che s'arrenda bene ai nuovi fatti sperimentali, ne scusa reve&shy;<lb/>rentemente il Filosofo e ne incolpa i commentatori. </s></p><p type="main">

<s>Una delle sottigliezze cardaniche da farne pi&ugrave; conto, vedemmo <lb/>esser quella, che l'Autore esercit&ograve; a definir la natura del moto vio&shy;<lb/>lento e a stabilire il principio d'inerzia. </s>

<s>Lo Scaligero si mise con <lb/>altre sottilit&agrave; a frugar dentro allo stesso soggetto, e non potendo <lb/>questa volta cogliere in fallo il suo nemico, lo punzecchia dicendo <lb/>ch'egli era venuto a insegnar cose note infino ai fanciulli, i quali <lb/>pur sanno <emph type="italics"/>vim impellentis nervi relictam in sagitta.<emph.end type="italics"/> L'esempio poi <lb/>del moto che rimane impresso nel mobile, come il calore nell'acqua, <lb/>dice essere stato addotto gi&agrave; dall'antico filosofo Temistio. </s>

<s>Del resto, <lb/>soggiunge lo Scaligero, che l'aria non abbia parte nel moto violento, <lb/>non occorrono a persuadercelo gli argomenti del Cardano, avendone <lb/>noi le certissime prove nell'esperienza. &ldquo; Quam vero ea ratio nulla <lb/>sit satis patebit demonstratione. </s>

<s>Sit levissima tabula ex qua exi&shy;<lb/>matur orbis torno aut circino incidente, ita ut sine mutuo attritu <lb/>orbis ille intra illud cavum circumagi queat &rdquo; (ibi pag. </s>

<s>130). Fatta <lb/>girar la ruzzola, per via di un manubrio infisso, ella seguita a gi&shy;<lb/>rare anco quando sia rimossa la mano. </s>

<s>Or dov'&egrave; qui l'aria, domanda <lb/>lo Scaligero, che mantien vivo nella stessa ruzzola il moto? </s>

<s>Quella <lb/>che riman dentro al sottilissimo fesso &egrave; s&igrave; poca, da non si creder <lb/>capace di produr quell'effetto. </s></p><p type="main">

<s>Chi leggendo queste parole del peripatetico di Verona, si ri&shy;<lb/>sovviene di una simile esperienza descritta, a provar lo stesso in&shy;<lb/>tento, da Galileo, rester&agrave; preso da qualche maraviglia, la quale gli <lb/>si dovrebbe accrescere anche di pi&ugrave; passando alla 331 Esercitazione, <lb/>dove l'Autore tratta della forza della percossa. </s>

<s>Ivi, dop'aver confu&shy;<lb/>tate le puerilit&agrave; del Cardano e avervi sostituito quel principio vero <pb xlink:href="020/01/071.jpg" pagenum="52"/>che il moto al mobile grave aggiunge sempre pi&ugrave; peso; commemora <lb/>affettuosamente il suo Maestro, unico interprete de'disegni archi&shy;<lb/>tettonici di Bramante, il qual Maestro aveva calcolato qual propor&shy;<lb/>zione avesse il pugno dell'uomo in quiete col pugno che ferisce. <lb/>&ldquo; Sed et haec et alia tunc illa demonstrabat, quae postea fortunae <lb/>saevitia interiere. </s>

<s>&rdquo; Che se invece fosse stata la fortuna propizia, <lb/>avremmo avuto in Giovanni Del Giocondo quella parte di scienza <lb/>Nuova quasi un secolo prima di Galileo. </s></p><p type="main">

<s>E pi&ugrave; di un secolo prima aveva lo stesso Scaligero preannun&shy;<lb/>ziata quella verit&agrave; tanto contraria agli oracoli aristotelici che cio&egrave; la <lb/>luce, come il suono, si muove in tempo e n&ograve; in istante, verit&agrave; a <lb/>dimostrar la quale, si faticarono inutilmente Galileo e i pi&ugrave; insigni <lb/>sperimentatori della sua scuola. &ldquo; Non enim ab immaterialitate <lb/>ductum argumentum, egli dice, satis validum est. </s>

<s>Nam neque soni <lb/>species, quae aeque immaterialis est, sine tempore defertur &rdquo;<lb/>(pag. </s>

<s>873). </s></p><p type="main">

<s>Or chi, oltre alle cose qui sopra esposte, ripensi all'importanza <lb/>che ebbero queste dottrine ne'progressi dell'ottica, e alla pi&ugrave; grande <lb/>importanza che ebbe le questione del vacuo, la quale si pose dallo <lb/>Scaligero, pur contro alle comuni dottrine aristoteliche, per condi&shy;<lb/>zione essenziale alla natura del moto; s'avvedr&agrave; quanto diritto <lb/>s'abbian questi farraginosi volumi, che abbiam nel presente para&shy;<lb/>grafo squadernati innanzi ai nostri lettori, ad esser commemorati <lb/>in una storia del metodo sperimentale in Italia. </s></p><p type="main">

<s>Un altro nome, oltre allo Scaligero, che si collega, bench&egrave; con <lb/>altro vincolo e per altro richiamo al Cardano, &egrave; quello di Niccol&ograve; <lb/>Tartaglia, nato in Brescia intorno al 1500 e morto 57 anni dopo. </s>

<s><lb/>Ei si potrebbe senza dubbio annoverare tra quei cultori dell'arte, <lb/>de'quali parleremo pi&ugrave; sotto, che non avendo avuto a maestri i <lb/>libri ma la stessa Natura, e non essendo perci&ograve; rimasti offesi dai <lb/>pregiudizi peripatetici, poterono liberamente correr la via de'loro <lb/>progressi. </s>

<s>Quel che infatti il Papadopoli afferma esser cio&egrave; venuto <lb/>Niccol&ograve; con Lodovico Balbisone allo studio di Padova, non s'&egrave; po&shy;<lb/>tuto ancora provare con documenti, e dall'altra parte &egrave; assai chiara <lb/>la storia che ne'<emph type="italics"/>Quesiti e Inventioni<emph.end type="italics"/> fa l'Autore di s&egrave; e de'suoi <lb/>studii. </s></p><p type="main">

<s>Lo stile incolto, con ch'&egrave; scritto quel libro e l'altro della <emph type="italics"/>Nuova <lb/>Scientia<emph.end type="italics"/> dello stesso Tartaglia, ci confermano in quella opinione e <lb/>costituiscono uno de'punti pi&ugrave; caratteristici della somiglianza che <lb/>passa tra Niccol&ograve; da Brescia e Leonardo da Vinci; somiglianza <pb xlink:href="020/01/072.jpg" pagenum="53"/>esteriore di forma, che fa presentire una pi&ugrave; intima somiglianza <lb/>della materia e del soggetto proprio de'loro studi. </s>

<s>Chi volesse poi <lb/>scorgere quel tal punto di somiglianza un po'pi&ugrave; d'appresso, non <lb/>dovrebbe far altro che mettersi a confrontare la prima carta de'<emph type="italics"/>Que&shy;<lb/>siti e Inventioni,<emph.end type="italics"/> dove si espongono i soggetti da trattarsi ne'primi <lb/>sei libri, con la lettera che Leonardo scriveva a Lodovico Moro, <lb/>perch&egrave;, riconosciutane l'abilit&agrave;, si risolvesse di richiamarlo pi&ugrave; sol&shy;<lb/>lecitamente al suo servizio. </s></p><p type="main">

<s>Ma il Bresciano, che rimane inferiore a quel da Vinci nella <lb/>variet&agrave; e nella estensione de'soggetti naturali trattati, lo supera <lb/>nella intensit&agrave; e nel lucido ordine con che &egrave; riuscito a trattare le <lb/>parti. </s>

<s>La <emph type="italics"/>Nuova Scientia,<emph.end type="italics"/> per verit&agrave;, non ha molto del nuovo. </s>

<s>La <lb/>legge della caduta dei gravi &egrave; quella stessa professata da Leonardo <lb/>da Vinci e da tutti coloro che rimasero ingannati dal creder che <lb/>gl'impeti sieno proporzionali alle altezze d'onde discendono i corpi. </s>

<s><lb/>Rispetto alla curva descritta dai proietti, il Tartaglia rimane indietro <lb/>al Cardano, che intravide nelle curve traiettorie una certa somi&shy;<lb/>glianza colla parabola. </s>

<s>Nonostante &egrave; notabile che fosse dalle sotti&shy;<lb/>gliezze geometriche condotto a indovinare la massima ampiezza <lb/>de'tiri di artiglieria aversi allora, quando l'obice &egrave; inclinato di 45 <lb/>gradi sull'orizzonte. </s>

<s>Poco perci&ograve; sembra che giovasse a scoprir cose <lb/>nuove l'ordine matematico tenuto dall'Autore e la lucida esposi&shy;<lb/>zione del libro. </s>

<s>Pi&ugrave; novit&agrave; forse ha nell'altro delle <emph type="italics"/>Inventioni,<emph.end type="italics"/> scritto <lb/>in Dialogo, e dove si contrappongono agli errori di Aristotile i veri <lb/>principii della statica. </s>

<s>Dialogizzando l'Autore con don Diego di Men&shy;<lb/>doza, nel VII libro introduce il discorso intorno alle Questioni mec&shy;<lb/>caniche di Aristotile, e segnatamente sopra la prima espressa dal <lb/>Filosofo in questa forma &ldquo; Perch&egrave; causa le maggior libre ovver <lb/>bilance sono pi&ugrave; diligenti delle minori. </s>

<s>&rdquo; Il Tartaglia esamina sot&shy;<lb/>tilmente la cosa e incomincia dall'osservare che il problema &egrave; di&shy;<lb/>fettoso nella stessa sua enunciazione e che sarebbe convenuto prima <lb/>di tutto all'Autore distinguere tra il fatto naturale e il fatto mate&shy;<lb/>matico. </s>

<s>Riguardate matematicamente le braccia della bilancia, come <lb/>linee geometriche, &egrave; vero, dice il Tartaglia, l'asserto di Aristotile, <lb/>ma &egrave; falso riguardate quelle stesse braccia fisicamente, e tali quali <lb/>sono in natura, perch&egrave; allora, invece di essere pi&ugrave; diligenti le bi&shy;<lb/>lancie di lunghe braccia sono invece quelle di braccia corte, come <lb/>l'esperienza dimostra nelle bilancette o saggiatori degli orefici e <lb/>dei monetari. </s></p><p type="main">

<s>La questione meccanica sottilmente discussa qui dal Bresciano, <pb xlink:href="020/01/073.jpg" pagenum="54"/>&egrave; notabilissima, perch&egrave; forse &egrave; la prima volta che il testo aristotelico <lb/>si accusi di errore a viso aperto. </s>

<s>E bench&egrave; l'Ambasciatore cesareo, <lb/>interlocutore nel Dialogo, non si conducesse cos&igrave; facilmente a cre&shy;<lb/>dere la cosa, perch&egrave; Aristotile <emph type="italics"/>non era un oca,<emph.end type="italics"/> l'Autore pure lo <lb/>persuade con buone ragioni, concludendo che il Filosofo era incorso <lb/>in tal grossolano errore, perch&egrave; a lui mancava la <emph type="italics"/>scienza dei pesi,<emph.end type="italics"/><lb/>ossia i principii della statica, de'quali il Tartaglia poi di proposito <lb/>passa a trattar nel seguente VIII libro delle <emph type="italics"/>Inventioni.<emph.end type="italics"/></s></p><p type="main">

<s><emph type="center"/>VII.<emph.end type="center"/></s></p><p type="main">

<s>Abbiamo detto che il Tartaglia f&ugrave; de'primi a notare gli errori <lb/>aristotelici a viso aperto: gli esempi infatti recati dal Fracastoro, <lb/>dallo Scaligero, e da molti altri hanno mostrato una certa trepida&shy;<lb/>zione, ogni volta che son dovuti mettersi a contradire al loro e <lb/>universale Maestro. </s>

<s>Il Cardano stesso intrattien lunghi discorsi qua <lb/>e l&agrave; per iscusarsene, e non trova altro migliore espediente a placar <lb/>gli animi degli scandalizzati, che di accusar le corruzioni del testo <lb/>e l'ignoranza dei commentatori. </s>

<s>Ma il rimprovero che in uno dei <lb/>passi da noi sopra citati fa a coloro, che troppo audacemente vo&shy;<lb/>levano imitarlo, in denunziar pubblicamente i falli dell'oracolo <lb/>venerato, mostra che negli ingegni speculativi ferveva un segreto <lb/>ardore di conquistare la propria libert&agrave;, per cui poco stette che <lb/>que'tumulti cos&igrave; compressi, uscirono in una guerra combattuta in <lb/>campo aperto, in mezzo al quale f&ugrave; de'primi e pi&ugrave; animosi a com&shy;<lb/>parire il Tartaglia, senza visiera. </s></p><p type="main">

<s>Il campo tenuto dal Tartaglia per&ograve; era circoscritto e ristretto <lb/>nelle questioni della meccanica e in alcuni problemi di fisica, di <lb/>che non restavan contenti i filosofi che intendevano oramai di con&shy;<lb/>quistare la loro piena libert&agrave; in ogni genere di scientifica cultura. </s>

<s><lb/>A capitanar la numerosa falange, uscita fuori a questa nuova con&shy;<lb/>quista, insorsero principalmente Bernardino Telesio consentino, e <lb/>Francesco Petrinsevich, dalmata, conosciuto sotto il nome latiniz&shy;<lb/>zato di Patricio, per noi Patrizio, ambedue i quali dettero opera a <lb/>speculare una nuova Filosofia della Natura, da contrapporsi a quella <lb/>dello Stagirita. </s>

<s>Il Patrizio, nel II tomo delle sue <emph type="italics"/>Discussioni,<emph.end type="italics"/> an&shy;<lb/>dava liberamonte scrivendo che l'ammirazione avuta da tutti per <pb xlink:href="020/01/074.jpg" pagenum="55"/>Aristotile era immeritata, imperocch&egrave; moltissime delle cose scritte <lb/>da lui son desunte da pi&ugrave; antichi filosofi, specialmente pitagorici, <lb/>e altrove pi&ugrave; ricisamente soggiunge che Aristotile stesso ne'suoi <lb/>libri poco o nulla ha del suo. </s></p><p type="main">

<s>Da ci&ograve; &egrave; facile intravedere la risoluzione presa dal Filosofo <lb/>dalmata di rivolgersi ad altre scuole e con preferenza alla pitagorica <lb/>e alla platonica, o meglio di speculare colla sua propria ragione, <lb/>piuttosto che con quella del preteso maestro di coloro che sanno. </s>

<s><lb/>Una tal animosa risoluzione viene eloquentemente espressa dal&shy;<lb/>l'Autore in quella Apologia, che egli scrisse contro un tal Teodoro <lb/>Angeluzio, che s'era accanitamente posto contro i nuovi insorti a <lb/>difendere il sacro regno peripatetico. </s>

<s>&ldquo; Ma regnate, egli dice in la&shy;<lb/>tino eloquio, regnate, infintanto che a voi &egrave; lecito o piace. </s>

<s>Noialtri <lb/>omiccioli lasciateci vivere, lasciateci spirar quest'aure, che sono a <lb/>tutti comuni, permetteteci sentimenti e idee, che non sieno aristo&shy;<lb/>teliche. </s>

<s>Non ci disprezzate, non ci avventate ingiurie, non carica&shy;<lb/>teci di calunnie. </s>

<s>Non vi adirate con noi, perch&egrave; non guardiamo ai <lb/>medesimi obietti e non accolghiamo i medesimi responsi. </s>

<s>Permet&shy;<lb/>teci poter esser platonici, se vogliamo, e in Filosofia piuttosto amici <lb/>a Plotino a Proclo a Damascio, che a que'vostri omaccioni, Averrois, <lb/>Duns, Janduno, Tartareto, e simili altre filosofiche quisquiglie. </s>

<s>Per <lb/>metteteci di pensare anche qualche cosa col nostro ingegno, tenue <lb/>s&igrave; ma libero. </s>

<s>Non ci siate tiranni n&egrave; vogliate implicarci nelle reti <lb/>delle vostre contenzioni o avvolgerci fra le tenebre de'vostri dom&shy;<lb/>mi &rdquo; (Ferrariae, 1584, pag. </s>

<s>4). </s></p><p type="main">

<s>Da cos&igrave; fatte parole del Patrizio, come da altre simili che si <lb/>potrebbero citar dal Telesio, si sentono spirar con impeto le aure <lb/>della libert&agrave;, ma quell'impeto &egrave; temperato, e se fa piegar gagliar&shy;<lb/>damente le fronde, pur non le schianta. </s>

<s>Non &egrave; cos&igrave; de'due altri <lb/>insorti a detronizzare Aristotile poco dopo i tempi del filosofo con&shy;<lb/>sentino e del dalmata. </s>

<s>Essi sono due frati, che perci&ograve; ingaggiano <lb/>una doppia battaglia, contro i Filosofi e contro i Teologi dei loro <lb/>tempi e hanno fieramente impugnato le armi contro due regni fra <lb/>s&egrave; confederati: quello del Peripato e quello della Scolastica. </s>

<s>L'uno <lb/>di que'due, nato a Nola, verso la met&agrave; del secolo XVI, e spento <lb/>nel 1600 per morte violenta, &egrave; il celebre Giordano Bruno, l'altro, <lb/>nato in Stilo di Calabria e che pass&ograve; molta parte della vita, decor&shy;<lb/>sagli dal 1568 al 1639, nel fondo di una carcere, &egrave; il non men ce&shy;<lb/>lebre Tommaso Campanella. </s>

<s>Son due fieri ingegni: lo spirito di li&shy;<lb/>bert&agrave; soffia dal loro petto, colla furia incomposta dell'uragano, per <pb xlink:href="020/01/075.jpg" pagenum="56"/>cui l'uno incontr&ograve; la carcere e l'altro il rogo. </s>

<s>Nessuno in Filosofia <lb/>ne sa'quanto loro: Aristotile, per Giordano, &egrave; un povero ingegno <lb/>meschino, pel Campanella &egrave; uno stolto. </s></p><p type="main">

<s>A cos&igrave; fatti arditissimi ingegni si suol da'moderni dare il no&shy;<lb/>me di <emph type="italics"/>Razionalisti,<emph.end type="italics"/> e son la delizia e l'ammirazione degli scrittori <lb/>de'nostri tempi, alcuni de'quali riconoscono in essi i precursori <lb/>del metodo sperimentale, e altri, con pi&ugrave; ardente zelo, gli venerano <lb/>come confessori e martiri del libero pensiero. </s>

<s>Non &egrave; del proposito <lb/>nostro trattar di confessioni o di martirii, ma della scoperta de'veri <lb/>sperimentali, in cooperare alla quale scoperta, giova, con breve e <lb/>diligente esame veder qual fosse veramente il merito di quegli <lb/>ammirati filosofi peregrini. </s></p><p type="main">

<s>Chi provasse piacere di sentirsi portato in aria sull'ali di me&shy;<lb/>tafisiche speculazioni, e veder dalla fantasia architettati i mondi, <lb/>potrebbe per prima cosa, fra gli altri libri, scegliere quel che il <lb/>Telesio intitol&ograve; <emph type="italics"/>De natura iuxta propria principia.<emph.end type="italics"/> Chi desiderasse <lb/>poi di scendere a cose pi&ugrave; positive, potrebbe dello stesso Autore <lb/>leggere i Commentarii, che egli scrisse pur <emph type="italics"/>De Rerum Natura,<emph.end type="italics"/> ma <lb/>a chi piacesse meglio vedere in pi&ugrave; ristretto campo condensate e <lb/>raccolte le virt&ugrave; dello scrittore, basterebbe si rivolgesse a que'tre <lb/>brevi opuscoli stampati separatamente in Napoli, tutti e tre nel me&shy;<lb/>desimo anno 1570, e nel primo de'quali si tratta de'fenomeni che <lb/>si osservan nell'aria, nel secondo, di ci&ograve; che accade nel mare, e <lb/>si d&agrave; nel terzo la teoria de'colori. </s></p><p type="main">

<s>Nel primo di quegli opuscoli piglia ad esaminare il Telesio le <lb/>teorie fisiche professate da Aristotile circa all'origine delle pioggie <lb/>e dei venti, e nega che questi, sempre, come vuole il Filosofo, si <lb/>generino dalle umide esalazioni della terra. </s>

<s>Egli avverte, al contrario, <lb/>che per lo pi&ugrave; i venti si levano su dal mare, il quale, pi&ugrave; che la <lb/>terra stessa, offre abbondante copia di umidit&agrave;, che rarefatta al calor <lb/>del sole si trasforma in esalazione ventosa. </s>

<s>Di qui si comprende <lb/>intanto che il filosofo di Cosenza, censore acuto del filosofo di Sta&shy;<lb/>gira, non fa poi altro che ritornar sui medesimi errori fisici di lui, <lb/>il quale, ingannato dagli effetti dell'evaporazion dell'acqua al calore, <lb/>si dava facilmente a credere che l'acqua stessa si trasformasse nella <lb/>sostanza del vento. </s></p><p type="main">

<s>N&egrave; miglior fisico dell'antico si mostra il nuovo nell'altro opu&shy;<lb/>scolo, dove tratta della salsedine del mare e del flusso e riflusso. </s>

<s><lb/>Diceva Aristotile che il mare era salato perch&egrave; il sole, facendolo <lb/>evaporare, ne avea sottratta la parte dolce. </s>

<s>Il Telesio osserva che <pb xlink:href="020/01/076.jpg" pagenum="57"/>ci&ograve; non pu&ograve; essere, perch&egrave; i fiumi restituiscono tutto ci&ograve; che il <lb/>calor solare ne asciuga, per cui conclude, nel capitolo IV, che il <lb/>mare stesso &egrave; salato di sua natura, e che &egrave; scaturito, come si vede <lb/>nell'acque dolci, da salse fonti di sotto terra. </s>

<s>Nel terzo opuscolo il <lb/>disprezzator di Aristotile non sa dir de'colori nulla di meglio di <lb/>quel che Aristotile stesso avesse insegnato. </s>

<s>Il lettore esce da quegli <lb/>intricati discorsi del Cosentino persuaso che all'opinione peripate&shy;<lb/>tica, secondo la quale i colori si generano da un contemperato pro&shy;<lb/>porzionamento d'ombra mescolata alla luce, non s'&egrave; saputo aggiun&shy;<lb/>ger nulla di nuovo. </s></p><p type="main">

<s>N&egrave; nulla di nuovo pure, sa, in simili fatti di fisica sperimen&shy;<lb/>tale, scoprire il Patrizio, bench&egrave; nell'Opera sua che egli fastosamente <lb/>intitola <emph type="italics"/>Nova de universis Philosophia<emph.end type="italics"/> si faccia architettore di quat&shy;<lb/>tro nuovi mondi. </s>

<s>A pi&ugrave; umile prosa scende il filosofo dalmata in <lb/>un suo libro, che egli intitola <emph type="italics"/>Della rettorica degli antichi,<emph.end type="italics"/> stam&shy;<lb/>pato in Venezia nel 1562. Se nella Nuova Filosofia l'autore imita <lb/>Platone nell'altezza delle speculazioni, in questo libro della Retto&shy;<lb/>rica lo imita in quella sua graziosa e facile maniera di presentar <lb/>la scienza sotto forma di apologhi, fra'quali apologhi &egrave; principal&shy;<lb/>mente notabile quello che il Patrizio finge essere stato da un abis&shy;<lb/>sino raccontato al conte Baldassarre Castiglione. </s>

<s>In quel romanzo <lb/>dunque dell'abissino, che non pu&ograve; non far tornare alla memoria <lb/>quell'Eve armeno, il quale, nel X libro dello Stato di Platone, ri&shy;<lb/>suscitato da morte, racconta ai vivi i destini da s&egrave; veduti delle anime <lb/>umane; in quel romanzo si dice come la Terra fu un tempo cos&igrave; <lb/>rarefatta e spugnosa, che per la grande ampiezza del suo volume <lb/>confinava quasi col cielo. </s>

<s>Gli uomini abitavano a principio nella <lb/>cavit&agrave; di quella spugna, come in nidi beati, ma, essendosi poi in&shy;<lb/>superbiti, e osando levar la fronte orgogliosa contro gli Dei, Giove <lb/>di sopra coi fulmini e Plutone di sotto coi terremoti, incomincia&shy;<lb/>rono a scuotere orribilmente la Terra, la quale ricadde tutta nelle <lb/>proprie caverne, e rientr&ograve; in s&egrave; stessa, dando cos&igrave; occasione al for&shy;<lb/>marsi dei monti e delle valli, de'laghi di acqua dolce e dei mari. </s></p><p type="main">

<s>Si comprende bene come l'ingegnoso romanzo del Patrizio, <lb/>tendeva a dar la soluzione di due problemi: uno teologico del pec&shy;<lb/>cato originale, e l'altro geologico e paleontologico della formazion <lb/>della terra e del ritrovamento delle reliquie marine sull'alta cima <lb/>dei monti. </s>

<s>Quando, in sui principii del secolo XVIII, s'incomincia&shy;<lb/>rono dagli immaginosi scienziati stranieri ad architettare sistemi <lb/>geologici, Tommaso Burnet rinnovell&ograve; sul serio il <emph type="italics"/>Sogno galante<emph.end type="italics"/> e <pb xlink:href="020/01/077.jpg" pagenum="58"/>il <emph type="italics"/>Romanzo bizzarro<emph.end type="italics"/> dell'abissino. </s>

<s>Questi titoli, che non sono stati <lb/>ritrovati da noi, ma da quell'Antonio Vallisnieri, il quale, insieme <lb/>con Lazzaro Moro pose i fondamenti pi&ugrave; saldi alla nuova Scienza <lb/>della Geologia, bastano a qualificare i meriti che ebbe Francesco <lb/>Patrizio in ispecular quella sua nuova filosofia naturale. </s></p><p type="main">

<s>Spento Giordano Bruno, quando gi&agrave; Galileo aveva accesa in <lb/>Padova la nuova lampada della Scienza, che diffondeva il suo splen&shy;<lb/>dore per ogni parte d'Europa, e sopravvissuto il Campanella di ben <lb/>sette anni alla pubblicazione de'Dialoghi dei Massimi Sistemi, s'aspet&shy;<lb/>terebbe ognuno che questi due gran pensatori dovessero riuscir pre&shy;<lb/>cursori del metodo sperimentale pi&ugrave; prossimi e immediati di quel <lb/>che non fossero il Telesio e il Patrizio. </s>

<s>Ma rivolgiamo un po'lo <lb/>sguardo sui loro libri. </s></p><p type="main">

<s>Del Campanella il libro che scende a trattar di fatti fisici, in <lb/>qualche modo pi&ugrave; particolare, &egrave; forse quello dell'<emph type="italics"/>Astrologia.<emph.end type="italics"/> Ei si <lb/>pu&ograve; ben ridere delle opinioni di Aristotile e di Seneca, secondo le <lb/>quali, a confricar coll'aglio la calamita, si viene a toglierle la virt&ugrave; <lb/>sua nativa d'attrarre il ferro, essendo gi&agrave; da trent'anni pubblicata <lb/>la Fisiologia Nuova del Gilberto, e si pu&ograve; ridere altres&igrave; di quel che <lb/>credevasi da alcuni filosofi delle palle di piombo, che esplose dalla <lb/>canna, al gran calore si liquefanno, perch&egrave; gi&agrave; da sette anni il <emph type="italics"/>Sag&shy;<lb/>giatore<emph.end type="italics"/> era stato pubblicato da Galileo, ma l&agrave; dove il gran filosofo <lb/>si pone a investigar le cause naturali da s&egrave; medesimo, non sa, come <lb/>i peripatetici, far uso d'altro che della propria fantasia e del pro&shy;<lb/>prio discorso, co'quali due strumenti compone una Fisiologia contro <lb/>quella di tutte le sette, e inventa un nuovo sistema del mondo, re&shy;<lb/>pudiati tutti i precedenti, non eccettuato quello dello stesso Coper&shy;<lb/>nico. </s>

<s>Ma come saggio di quella Fisiologia che il Campanella vuol <lb/>sostituire e soprapporre alle Fisiologie di tutte le altre sette, basti <lb/>il commemorar le cause fisiche dalle quali, nel citato libro astro&shy;<lb/>logico, riconosce gli effetti dell'intumidire e del deprimersi, di sei <lb/>in sei ore, con vicenda continua, le acque del mare; cause che <lb/>non consistono in altro, secondo l'Autore, che nel calor del sole, <lb/>il quale opera a quel modo stesso che il fuoco di un fornello sopra <lb/>l'acqua della pentola messa ivi a bollire. </s>

<s>Del resto un sistema in&shy;<lb/>tero di Meteorologia &egrave; fatto nelle sue cause dipendere dalla natura, <lb/>dall'aspetto, dalle varie congiunzioni degli astri; e il filosofo che <lb/>tutto disprezza e in tutto crede d'avere a ritrovare egli il primo <lb/>qualche cosa di nuovo, non fa bene spesso altro che ripetere le pi&ugrave; <lb/>strane stranezze del Cardano. </s></p><pb xlink:href="020/01/078.jpg" pagenum="59"/><p type="main">

<s>Non &egrave; per&ograve;, secondo pretendono i suoi adoratori, cos&igrave; di Gior&shy;<lb/>dano Bruno: egli &egrave; per essi il riformatore della nuova Astronomia. </s>

<s><lb/>Che il sole &egrave; una stella, che le stelle son soli, che le comete son <lb/>pianeti, che i travi sono asteroidi, son dottrine espressamente in&shy;<lb/>segnate dal gran filosofo nolano, e che i filosofi posteriori hanno <lb/>ritrovate e professate per vere, come tanti anni prima erano state <lb/>predicate da lui. </s></p><p type="main">

<s>Noi, a tanto fulgore di scienza, ci sentiamo inchinare maravi&shy;<lb/>gliati le ciglia, e levandole poi in alto, domandiamo, con quella <lb/>libert&agrave; che ci &egrave; permessa da'nuovi evangelizzatori del libero esame: <lb/>in che modo scoperse il Bruno e annunzi&ograve; tante astronomiche ve&shy;<lb/>rit&agrave;? </s>

<s>Certo egli dee essere stato un osservatore diligentissimo dei <lb/>fenomeni celesti, e un abilissimo sperimentatore. </s>

<s>Ma nel fatto poi <lb/>quell'astronomo, che osservando un trave rasentare i tetti di Nola, <lb/>dal vederlo sorvolare alla cima del Monte Cicala, argomenta che <lb/>egli &egrave; animato e che si muove con ispontaneit&agrave; di moto, scansando <lb/>gl'impedimenti come un uccello; ci riesce men che un fanciullo, <lb/>per non dire a dirittura che egli dee essere un gran matto. </s>

<s>E quello <lb/>sperimentatore, il quale argomenta all'esistenza delle macchie cen&shy;<lb/>trali nel sole da ci&ograve; che si osserva in una sfera di ghiaccio, la <lb/>quale mostra pi&ugrave; fosca nel centro che verso la periferia del cerchio <lb/>massimo di proiezione, &egrave; tale da dover tornare ancora sotto la di&shy;<lb/>sciplina del pedagogo, che gl'infonda un buon pizzico di sale a <lb/>condirgli il cervello. </s></p><p type="main">

<s>N&egrave; scusa punto l'insipienza del Bruno il citar che fa Niccol&ograve; <lb/>da Cusa, come Autore della trovata rassomiglianza tra le macchie <lb/>del sole e ci&ograve; che si osserva dentro a una palla ghiacciata, non ve&shy;<lb/>dendosi come si possa spiegar con quella similitudine l'origine delle <lb/>macchie solari, secondo il concetto che se ne era formato il gran <lb/>filosofo nolano. </s>

<s>Questi infatti dice essere il sole una lucerna a olio, <lb/>per cui sembrerebbe che, tutt'altro che riconoscere l'apparenza <lb/>delle macchie solari nell'analogia de'raggi rifranti in una palla di <lb/>ghiaccio, ne avesse dovuto ritrovar l'origine nella rassomiglianza <lb/>delle parti fosche e delle chiare, che sempre si osservano intorno <lb/>alle fiamme delle nostre lucerne. </s>

<s>Questo stesso concetto infatti porse <lb/>occasione di filosofar sottilmente intorno all'origine e alla natura <lb/>delle macchie del sole a Benedetto Castelli, in una sua lettera a <lb/>Galileo (MSS. Gal. </s>

<s>Divis. </s>

<s>II, P. III, T. X, c. </s>

<s>55). Ma dal Castelli al <lb/>Bruno &egrave; un abisso di separazione, com'&egrave; tra il Bruno stesso e il <lb/>Keplero, vero distruttore delle fantastiche sfere aristoteliche, e tra <pb xlink:href="020/01/079.jpg" pagenum="60"/>il medesimo Bruno e il Borelli, a cui si dee l'aver prima di ogni <lb/>altro dimostrato con meccanici e fisici argomenti la teoria plane&shy;<lb/>taria delle comete. </s></p><p type="main">

<s>In ogni modo, si pu&ograve; domandare agli esagerati ammiratori: <lb/>quali sono i fisici argomenti addotti dal celebrato astronomo di <lb/>Nola? </s>

<s>Egli asserisce, per esempio, che la Terra si muove, non per <lb/>motore assistente, ma per proprio intrinseco impulso, come gli altri <lb/>pianeti. </s>

<s>Ebbene, volevasi domandare, asserisce egli ci&ograve; per avere <lb/>intraveduto il principio delle forze centrali, o per esser ricorso a <lb/>qualche rassomiglianza colle attrazioni magnetiche, come fecero il <lb/>Keplero e il Borelli, o almeno per esservi condotto da quella ana&shy;<lb/>logia che &egrave; tra il moto de'pianeti e de'nostri proietti, secondo il <lb/>concetto degli antichi pitagorici divulgato ne'libri di Plutarco? </s>

<s><lb/>Niente affatto &egrave; di ci&ograve;: l'impulso intrinseco, per cui si muove la <lb/>Terra, dice Giordano, &egrave; un principio di animalit&agrave; che l'avviva, come <lb/>avviva col sole tutti gli altri pianeti, e anzi tutti gli infiniti corpi <lb/>celesti. </s></p><p type="main">

<s>Una tale ipotesi &egrave; il segreto magico da cui il nostro Filosofo <lb/>fu condotto alle ammirate astronomiche scoperte, imperocch&egrave;, se <lb/>tutto &egrave; animato nel mondo, e se ogni principio di animalit&agrave; vuol <lb/>esser congiunto a un organo corporeo acconcio, ne vien per legit&shy;<lb/>tima conseguenza che il sole e la terra e le stelle e le comete, e <lb/>tutt'altro che si muove nel libero spazio, sieno informati alle me&shy;<lb/>desime leggi, non essendo tra loro altra variet&agrave; che di grandezza e <lb/>di moti. </s>

<s>S'aggiunga poi la dottrina trascendentale professata dal <lb/>Bruno delle contrariet&agrave;, che s'identificano nell'infinito, e si vedr&agrave; <lb/>come questa, applicata alla natura degli astri, dovesse condurlo a <lb/>incontrarsi in qualcuno di quei concetti, che hanno una somiglianza <lb/>o un'apparenza di veri. </s></p><p type="main">

<s>Ma quella di Giordano non era scienza n&egrave; di osservazioni n&egrave; <lb/>d'esperienze: era una metafisica strana e dai filosofi di miglior <lb/>senno repudiata: era una ipotesi, della quale ora si ridono piace&shy;<lb/>volmente gli stessi fanciulli. </s>

<s>Dove son dunque i meriti del procla&shy;<lb/>mato precursore del metodo sperimentale, o quali sono i prestigi <lb/>che hanno affascinati tanti suoi ammiratori? </s>

<s>Di questi prestigi uno <lb/>&egrave; senza dubbio l'aureola, come dicono, del martirio, e l'altro &egrave; <lb/>l'esempio dato dall'ardente Nolano della rivolta contro ogni auto&shy;<lb/>rit&agrave; sacra e profana, cosa che va tanto a genio de'settatori di lui, <lb/>ma il pi&ugrave; affascinatore &egrave; il buio delle filosofiche speculazioni. </s>

<s>&Egrave; una <lb/>grand'arte, a sedur certi ingegni com'usano sventuratamente oggidi <pb xlink:href="020/01/080.jpg" pagenum="61"/>fra noi, quella di saper dir cose che nessuno intende, o che cia&shy;<lb/>scuno pu&ograve; intendere a suo modo e ritrovarci il suo; arte dalla quale <lb/>dipende cos&igrave; la fortuna incontrata da Giordano Bruno, come quella <lb/>incontrata da tanti sistemi di Filosofia, e da tanti libri di lettera&shy;<lb/>tura, specialmente tedesca. </s></p><p type="main">

<s><emph type="center"/>VIII.<emph.end type="center"/></s></p><p type="main">

<s>Il soggetto, che ci &egrave; capitato a trattar fra mano, &egrave; di tale e <lb/>tanta importanza, che non si vuol passar da noi senza riflettere un <lb/>po'da senno sopra l'indole e i meriti di questi tanto famigerati <lb/>razionalisti. </s>

<s>E quanto all'indole, a noi sembra per verit&agrave; che non <lb/>differiscano dagli stessi peripatetici, anzi egli &egrave; certo che proseguono <lb/>e professano i medesimi principii, che son quelli di sostituire i pla&shy;<lb/>citi della ragione alla realt&agrave; de'fatti naturali. </s>

<s>Non si sa perci&ograve; com&shy;<lb/>prender da noi, com'essendo cos&igrave;, intendano gli uni di contrapporre <lb/>i loro metodi e le loro dottrine ai metodi e alle dottrine professate <lb/>dagli altri. </s>

<s>Il Telesio, il Patrizio, il Bruno e il Campanella, seguono <lb/>precisamente gli esempii di Aristotile, accomodando la Natura ai <lb/>loro proprii cervelli, e se ne dilungano in questo solo, in dir cio&egrave; <lb/>che il Filosofo antico non aveva accomodate le cose tanto bene, e <lb/>che perci&ograve; credono, coi loro nuovi sistemi, di averle accomodate <lb/>molto meglio di lui. </s></p><p type="main">

<s>La similitudine, dall'altra parte, e la parentela fra la Filosofia <lb/>vecchia e la nuova, &egrave; confermata dal veder che poi i frutti sono <lb/>stati gli stessi. </s>

<s>Se infecondi dello scoprimento di nuove cose in <lb/>natura sono stati i peripatetici, i razionalisti si son mostrati pi&ugrave; <lb/>infecondi che mai. </s>

<s>Le idee sparse per tanti loro libri ammirati son <lb/>simili a nuvole agitate dai venti o dlpinte di bei colori, ma da cui <lb/>non si spreme una stilla a rinfrescar le arsure dell'assetata cam&shy;<lb/>pagna. </s>

<s>Un indizio per&ograve; pi&ugrave; sicuro che quelle due scuole apparten&shy;<lb/>gono alla medesima stirpe &egrave; il vederle ambedue affette dal medesimo <lb/>peccato originale, peccato, che secondo s'accenn&ograve; altrove, consiste <lb/>nella vanit&agrave; e nell'orgoglio. </s>

<s>I dialoghi delle Due Nuove Scienze <lb/>contenevano bene altre novit&agrave; di quelle cos&igrave; pomposamente annun&shy;<lb/>ziate dalle due Nuove Filosofie sulla Natura del Teles&igrave;o e del Pa&shy;<lb/>trizio: e Galileo stesso ebbe a cogliere Aristotile in fallo, in bene <pb xlink:href="020/01/081.jpg" pagenum="62"/>altri fatti pi&ugrave; positivi di quel che non occorresse al Campanella e <lb/>al Bruno; e pur nonostante ei non lo disprezza come que'due frati, <lb/>e non gli avventa incontro titoli s&igrave; inverecondi. </s>

<s>Anzi, se spesso lo <lb/>confuta, non di rado anco lo commenta, e talvolta altres&igrave;, genero&shy;<lb/>samente lo loda. </s></p><p type="main">

<s>Negheremo noi per questo ogni merito ai razionalisti? </s>

<s>No: essi <lb/>hanno anzi un merito singolare e perci&ograve; unico, il merito di aver <lb/>riconosciuto e protestato come quel diritto, che aveva Aristotile, lo <lb/>avevano anch'essi e tutti i loro fratelli: il diritto di far uso della <lb/>propria ragione. </s>

<s>Ecco da qual lato i razionalisti differiscono dai pe&shy;<lb/>ripatetici, ecco in che propriamente hanno merito d'esser detti <lb/>razionalisti. </s>

<s>I peripatetici, accettando per vero, perch&egrave; dall'altra <lb/>parte era assai comodo, che la Natura si dovesse assettare ai cer&shy;<lb/>velli degli uomini, scelsero come misura d'ogni sapienza il pi&ugrave; gran <lb/>cervello stimato da loro, che fu quello di Aristotile, e lo insignirono <lb/>di tanta autorit&agrave; magistrale, che ogni questione, in fatto di cose <lb/>naturali, si decideva dagli oracoli e dai responsi di lui. </s>

<s>I razionalisti <lb/>per&ograve; si levarono a dire che quello di Aristotile non era poi quel <lb/>gran cervello che si credeva, e che ce n'erano o ce ne potevano <lb/>essere de'pi&ugrave; sottili di lui, per cui uno per esempio citava il cer&shy;<lb/>vello di Platone, e un'altro, com'&egrave; pi&ugrave; naturale, il cervello suo <lb/>proprio. </s>

<s>Questi secondi furono de'pi&ugrave; arditi e intesero a scuotere <lb/>il giogo di ogni autorit&agrave;, per cui da molti sono stati encomiati e <lb/>benedetti. </s>

<s>Non si accorgon per&ograve; costoro, che scotendosi cos&igrave; anche <lb/>il giogo della Natura, e invece di assoggettarsi essi a lei, preten&shy;<lb/>dendo che ella debba assoggettarsi a loro, tornano perci&ograve; alla scienza, <lb/>lasciamo star la Religione e la Morale, pi&ugrave; nocivi degli stessi pe&shy;<lb/>ripatetici. </s></p><p type="main">

<s>Che sia anzi cos&igrave; di fatto, che cio&egrave; il razionalismo sia riuscito <lb/>pi&ugrave; nocivo alle scienze sperimentali dello stesso peripaticismo, si <lb/>pu&ograve; vedere dai frutti. </s>

<s>Imperocch&egrave; essendosi quello ribellato a ogni <lb/>autorit&agrave; magistrale, rimase come un ramo reciso dall'albero di cia&shy;<lb/>scuna delle due scuole, della platonica e della aristotelica, e si rese <lb/>perci&ograve; incapace di menar frutti proprii dell'una e dell'altra. </s>

<s>E quali <lb/>sono questi frutti? </s>

<s>Lo dicemmo gi&agrave; di sopra: frutti del Peripato <lb/>sono i calcoli numerici e algebrici; e frutti dell'Accademia sono <lb/>la Geometria astratta e l'applicata. </s>

<s>Ora &egrave; un fatto che dalla scuola <lb/>del razionalismo del Patrizio e del Bruno non usc&igrave; fuori n&egrave; un <lb/>geometra mai n&egrave; un algebrista. </s></p><p type="main">

<s>Nel decorrere del secolo XVI que'due alberi della scienza del <pb xlink:href="020/01/082.jpg" pagenum="63"/>Peripato e dell'Accademia, ciascuno nella sua specie, si mostr&ograve; lar&shy;<lb/>gamente fecondo. </s>

<s>Se Luca Paciolo, aveva gi&agrave; nel secolo precedente <lb/>ritrovato il metodo da risolvere l'equazioni de'due primi gradi, <lb/>Girolamo Cardano e Niccol&ograve; Tartaglia rivaleggiano insieme a fare <lb/>a chi produce la pi&ugrave; semplice formula da risolvere l'equazioni del <lb/>terzo e del quarto grado. </s>

<s>Raffaello Bombelli, bolognese, &egrave; il primo <lb/>ad osservar, nella sua Algebra stampata nel 1579, che nel cos&igrave; detto <lb/><emph type="italics"/>caso irriducibile,<emph.end type="italics"/> le parti della formula rappresentanti una radice <lb/>compongono insieme una radice reale, e Francesco Maurolico for&shy;<lb/>mula le prime leggi, secondo cui procedono le serie e le somme <lb/>delle stesse serie dei numeri naturali, quadrati, triangolari e cosi <lb/>via via. </s></p><p type="main">

<s>L'Accademia poi dette in quel medesimo secolo il pi&ugrave; lauto <lb/>frutto che si potesse imbandire al convito della scienza: il sistema <lb/>vero del mondo. </s>

<s>Che un tal frutto veramente allegasse nel fiore di <lb/>quella Filosofia, eloquentemente esposta in quel dialogo del Timeo <lb/>scritto dal discepolo di Pitagora, si presente dagli odori esalanti qua <lb/>e l&agrave; per le platoniche carte di Niccol&ograve; Copernico. </s>

<s>&ldquo; Chi, egli dice <lb/>a persuader la verit&agrave; del nuovo sistema, collocherebbe, in questo <lb/>bellissimo tempio questa lampada in altro miglior luogo, che in <lb/>quello, d'onde ella potesse tutto insieme illuminarlo? </s>

<s>E in verit&agrave; <lb/>non a torto alcuni chiamano il sole lucerna del mondo, altri Mente, <lb/>altri Rettore. </s>

<s>Trismegistio lo chiama visibile Dio, e Sofocle, nel&shy;<lb/>l'Elettra, occhio che vede tutto. </s>

<s>Cos&igrave; di fatto, risedendo il sole nel <lb/>suo regal soglio, governa la famiglia degli astri, che gli rigirano <lb/>intorno. </s>

<s>La terra stessa non &egrave; defraudata del lunar ministero, ma, <lb/>come Aristotile dice, la Luna &egrave; alla Terra cognata. </s>

<s>Ella concepisce <lb/>intanto per opera del sole e s'impregna dell'annuale suo parto. </s>

<s><lb/>Ritrovasi dunque in cos&igrave; fatto ordinamento una simmetria tanto <lb/>ammiranda fra le parti del mondo, un cos&igrave; stabile nesso fra i moti <lb/>e le grandezze degli orbi, che in altro modo non sarebbe possibile <lb/>trovare di meglio. </s>

<s>&rdquo; </s></p><p type="main">

<s>Abbiamo scelto dal libro I <emph type="italics"/>De revolutionibus<emph.end type="italics"/> questo passo, <lb/>fra'tanti altri, perch&egrave; sommamente espressivo del carattere geome&shy;<lb/>trico di quelle prove, che ivi adduce l'Autore. </s>

<s>Poi suggerir&agrave; il Gil&shy;<lb/>berto i primi argomenti fisici, per quello almeno che concerne la <lb/>rotazion della terra dedotti dalla Nuova Fisiologia magnetica, e <lb/>pochi anni dopo Galileo confermer&agrave; il sistema con altri pi&ugrave; validi <lb/>argomenti desunti dalla rotazione del Sole, dalla circolazione dei <lb/>satelliti intorno al centro di Giove e dalle osservazioni delle fasi <pb xlink:href="020/01/083.jpg" pagenum="64"/>rappresentate dai due pianeti inferiori. </s>

<s>Ma intanto il grande Astro&shy;<lb/>nomo prussiano che non ha ancora il minimo sentore di quelle <lb/>fisiche prove, si assicura di aver colto nel vero, scortovi unicamente <lb/>dalla Geometrizzante Natura, e si compiace di esser cos&igrave; riuscito a <lb/>risolvere il celebre problema pitagorico, proposto in cos&igrave; fatti ter&shy;<lb/>mini da Platone: &ldquo; quomodo per ordinatos circulares et &aelig;quales <lb/>motus salvari possunt ph&aelig;nomena. </s>

<s>&rdquo; </s></p><p type="main">

<s>Sembrerebbe che un altro frutto allegato e maturato negli orti <lb/>di Academo, allato all'Astronomia copernicana, dovesse esser l'Ot&shy;<lb/>tica. </s>

<s>Il carattere geometrico infatti di questa scienza persuase alcuni <lb/>autori a scrivere che ella fu coltivata principalmente dai discepoli <lb/>di Platone, e infatti dette opera a scriver dell'Ottica lo stesso <lb/>Euclide. </s>

<s>Dell'Ottica per&ograve; scrisse anche Tolomeo, le dottrine del <lb/>quale furono accolte e diffuse dall'arabo Alhazen, cosicch&egrave; pu&ograve; dirsi <lb/>che fosse questa scienza coltivata con egual profitto dalle due scuole. </s>

<s><lb/>N&egrave; ci&ograve; fa maraviglia, perch&egrave; se la platonica s'aiutava della Geome&shy;<lb/>tria, l'aristotelica si giovava del principio dell'intromissione delle <lb/>specie nell'occhio, mentre il principio platonico dell'estramissione <lb/>impediva grandemente alla scienza di progredire. </s>

<s>Di qui &egrave; che <lb/>s'intende come potesse avvantaggiarsi l'Ottica in Vilellione, il quale <lb/>ai placiti del Filosofo ateniese oppose la proposizione V del terzo <lb/>libro stampato per cura di Pietro Appiano in Norimberga nel 1551. <lb/>&ldquo; Impossibile est visum rebus visis applicari per radios ab oculis <lb/>egressos. </s>

<s>&rdquo; Le prove di ci&ograve; addotte dall'Autore sono inoppugnabili. </s>

<s><lb/>Se i raggi visivi, egli dice, escon dall'occhio o son corporei o sono <lb/>incorporei. </s>

<s>Se corporei, com'&egrave; possibile che lo spirito visivo si <lb/>diffonda cos&igrave; corporalmente infino alle pi&ugrave; lontane stelle? </s>

<s>se in&shy;<lb/>corporei, come possono far impressione corporale sopra gli organi <lb/>de'sensi? </s></p><p type="main">

<s>In cos&igrave; argomentare, accenna il famoso Autore pollacco a una <lb/>questione, che teneva incerte tutte le scuole di que'tempi, ed &egrave; la <lb/>questione celebre della natura della luce, dalla soluzion della quale <lb/>dovevano dipendere le future sorti dell'Ottica. </s></p><p type="main">

<s>Francesco Maurolico non riusc&igrave; a risolvere la difficile questione, <lb/>ma egli &egrave; nulladimeno il primo che preluda ai progressi dell'ottica <lb/>neutoniana. </s>

<s>I <emph type="italics"/>Photismi de Lumine et umbra,<emph.end type="italics"/> ossia la Calottrica, e <lb/>i <emph type="italics"/>Diaphanorum partes<emph.end type="italics"/> ossia la Diottrica furono due libri scritti dal&shy;<lb/>l'Autore in sul finir della prima met&agrave; del secolo XVI, e nonostante <lb/>non videro la luce prima del 1611 in Napoli, quando i fisici si sen&shy;<lb/>tivan vivamente frugati dal desiderio d'intendere in che modo quei <pb xlink:href="020/01/084.jpg" pagenum="65"/>vetri del canocchiale avessero la misteriosa virt&ugrave; d'ingrandire gli <lb/>oggetti. </s>

<s>Il Maurolico nella Diottrica aveva data la teoria, non delle <lb/>lenti accoppiate ma delle semplici, e meglio di tutti quei che gli <lb/>successero per molti anni, dimostr&ograve; l'effetto che facevano sulla vista <lb/>dei giovani e dei vecchi le varie rifrangenze dei raggi attraverso <lb/>al diafano degli occhiali. </s>

<s>Fu il nostro messinese altres&igrave; il primo a <lb/>dimostrar le aberrazioni di sfericit&agrave;, e a divisare il modo del di&shy;<lb/>pingersi le immagini reali e rovesciate attraverso alle sfere cristal&shy;<lb/>line e alle lenti convesse. </s>

<s>Ei riconobbe inoltre l'origine de'colori <lb/>in una certa costipazione, che subiscono i raggi variamente rifratti <lb/>attraverso al diafano de'prismi triangolari, e applic&ograve; una tale dot&shy;<lb/>trina alle gocciole delle nubi, per cui si disegnano e si coloriscono <lb/>gli archi celesti. </s></p><p type="main">

<s>Mirabile &egrave; per que'tempi il giudizioso modo di procedere del <lb/>nostro Abbate di Santa Maria in Porto. </s>

<s>Egli seppe destramente co&shy;<lb/>gliere i frutti menati da ambedue le filosofie dominanti. </s>

<s>Nell'Al&shy;<lb/>gebra e nell'Ottica non fu meno valoroso che in Geometria. </s>

<s>Da <lb/>quasi un secolo ei preveniva la dimostrazione delle proposizioni <lb/>geometriche degl'inscritti e dei circoscritti, alle quali il Torricelli <lb/>credette di avere atteso per il primo, fintantoch&egrave; non venne a farlo <lb/>ravveder del suo errore una lettera di Michelangiolo Ricci (MSS. <lb/>Gal., Dis. </s>

<s>T. XLII c. </s>

<s>145); lettera che &egrave; un importante documento <lb/>di storia, essendo che per essa apparisce come si fosse in Italia <lb/>atteso ad osservare diligentemente le forme cristalline dei sali, molti <lb/>anni prima che, all'occasione di studiar l'organo del gusto, vi at&shy;<lb/>tendessero il Bellini e il Malpighi. </s></p><p type="main">

<s>Tali insomma furono i frutti che si raccolsero nel secolo XVI <lb/>dalle due filosofie peripatetica e accademica, frutti cospicui e glo&shy;<lb/>riosi alla scienza italiana, specialmente se si ripensi a quai passi si <lb/>condusse a fare in que'tempi l'Algebra e l'Astronomia. </s>

<s>Abbiamo <lb/>detto che furono ambedue questi frutti gloriosi alla scienza italiana, <lb/>perch&egrave; lasciano stare le antiche tradizioni pitagoriche, le quali si <lb/>posson dire in qualche modo italiane, il grande Astronomo turonese <lb/>ebbe pi&ugrave; immediata preparazione in Niccol&ograve; da Cusa e nel Fraca&shy;<lb/>storo; ebbe in Domenico Maria Novara maestro italiano, e s'educ&ograve; <lb/>il giovane ingegno ai due de'pi&ugrave; fiorenti nostri studii di Padova e <lb/>di Bologna. </s></p><p type="main">

<s>Ma quali altri frutti si raccolsero della Filosofia razionalistica? </s>

<s><lb/>Aerei sistemi nel Telesio e nel Patrizio: balenanti nubi gravide di <lb/>tempesta in Giordano Bruno e nel Campanella, dentro alle bizzarre <pb xlink:href="020/01/085.jpg" pagenum="66"/>e capricciose forme delle quali filosofiche nubi, i loro ammiratori <lb/>intravidero annunziate e scoperte verit&agrave;, a quel modo che Leonardo <lb/>da Vinci intravedeva cavalli e cavalieri ordinati in battaglia, nei <lb/>muschi degli alberi, negli sputi e in altre macchie rimaste a caso <lb/>sull'intonaco dei muri. </s></p><p type="main">

<s><emph type="center"/>IX.<emph.end type="center"/></s></p><p type="main">

<s>Abbiamo fin qui parlato di scuole e di libri, e de'frutti di <lb/>scienza sperimentale raccolti dai loro insegnamenti. </s>

<s>Ma que'frutti, <lb/>a riguardarli bene, ci si trovan fra mano assai scarsi, e quei pochi <lb/>e de'migliori si son riconosciuti uscir da tutt'altra fonte che da <lb/>quella de'libri filosofici. </s>

<s>Si diceva gi&agrave;, in fin dai principii del no&shy;<lb/>stro Discorso, che delle due Filosofie dominanti una rendeva inutile <lb/>e l'altra impossibile ogni arte sperimentale, per cui vedemmo il <lb/>Cardano principalmente e il Tartaglia entrar coi settatori della <lb/>scuola in isdegnoso dissidio. </s></p><p type="main">

<s>Ben per&ograve; pi&ugrave; risentitamente erano gi&agrave; que'dissidii insorti nel&shy;<lb/>l'animo di un'altra gente che, o dalle condizioni della nascita o dagli <lb/>esercizi della vita erano tenuti lontani dal partecipare ai puhblici <lb/>insegnamenti. </s>

<s>Amerigo Vespucci abbandona in giovent&ugrave; la scuola <lb/>di umanit&agrave;, per darsi alla mercanzia, e poi pi&ugrave; tardi ai viaggi. </s>

<s>Egli <lb/>non ha perci&ograve; a che far nulla con la scuola de'filosofi, e anzi si fa <lb/>ardito di rinfacciare i loro errori &ldquo; Parmi, Magnifico Lorenzo, che <lb/>la maggior parte dei filosofi in questo mio viaggio sia reprobata, <lb/>che dicono che dentro della torrida zona non si pu&ograve; abitare a causa <lb/>del gran calore, e io ho trovato in questo mio viaggio essere il <lb/>contrario &rdquo; (Bandini, Vita e lettere di A. Vespucci, Firenze 1745, <lb/>pag. </s>

<s>73). Egli sa di scrivere <emph type="italics"/>in barbaro stile e fuori di ogni ordine <lb/>di umanit&agrave;,<emph.end type="italics"/> e d&agrave; nonostante opera a scrivere un libro, che egli in&shy;<lb/>titola le <emph type="italics"/>Quattro Giornate<emph.end type="italics"/> &ldquo; nel quale ho relato, egli dice, la maggior <lb/>parte delle cose, che io vidi assai distintamente .... Quivi dunque io <lb/>viddi molte altre stelle i varii movimenti delle quali diligentemente <lb/>osservando, ne composi assegnatamente un libro &rdquo; (ivi, pag. </s>

<s>18 e <lb/>115). Ei si compiace delle tante nuove cose scoperte, e ripensando <lb/>alle sterilit&agrave;, e anzi agli errori in che versavano i filosofi <emph type="italics"/>in libris,<emph.end type="italics"/><lb/>conclude essere certo che <emph type="italics"/>pi&ugrave; vale la pratica che la teorica.<emph.end type="italics"/></s></p><pb xlink:href="020/01/086.jpg" pagenum="67"/><p type="main">

<s>Ben pi&ugrave; sdegnoso, perch&egrave; pi&ugrave; irritato, &egrave; l'animo di Leonardo <lb/>da Vinci, che scrive cos&igrave; contro i filosofi <emph type="italics"/>schonfiati<emph.end type="italics"/> e <emph type="italics"/>pomposi,<emph.end type="italics"/> non <lb/>ritrovatori di cose nuove, ma <emph type="italics"/>recitatori e trombetti delle opere al&shy;<lb/>trui.<emph.end type="italics"/> &ldquo; Se, bene, come loro, non sapessi allegare gli autori, molto <lb/>maggiore e pi&ugrave; degna cosa allegher&ograve; allegando l'esperienza maestra <lb/>ai loro maestri &rdquo;. (Libri Histoire et cet. </s>

<s>T. III, Paris 1840, pag. </s>

<s>238). </s></p><figure id="id.020.01.086.1.jpg" xlink:href="020/01/086/1.jpg"/><p type="main">

<s>Amerigo e Leonardo, che basterebbero per se stessi a provare <lb/>come la scienza della Natura si ricover&ograve; ne'suoi primi principii <lb/>altrove che per gli alloggiamenti de'Filosofi, non sono soli: essi <lb/>rappresentano un ordine di persone, che attende all'esercizio o delle <lb/>arti utili, o delle arti belle; ordine a cui principalmente apparten&shy;<lb/>gono Dante Alighieri, Cristoforo Colombo, Leon Battista Alberti. <pb xlink:href="020/01/087.jpg" pagenum="68"/>Illustre stuolo egli &egrave; questo, innanzi al quale il mondo de'Filosofi <lb/>sperimentali inchina per gran riverenza spontaneamente le ciglia. </s>

<s><lb/>Ebbene: di chi son discepoli tutti costoro, di Platone o di Aristo&shy;<lb/>tele? </s>

<s>Non hanno maestro nessun filosofo o accademico o peripate&shy;<lb/>tico, n&egrave; pretendono di farla da filosofi essi stessi come i razionalisti: <lb/>libro e maestro a loro &egrave; la Natura. </s>

<s>Dai faticosi esercizii dell'arte <lb/>si persuasero facilmente che la materia, sotto alle forme della <lb/>quale s'agita la vita dell'Universo, tutt'altro che essere arrendevole <lb/>al nostro ingegno, &egrave; sorda alle intenzioni dell'artista, ond'&egrave; che ap&shy;<lb/>presero di qui la soggezione agli ordini naturali e impararono ad <lb/>osservarli con diligente riverenza amorosa, ministri e sacerdoti nel <lb/>sacro Tempio, e non Iddei. </s>

<s>Essi dunque rappresentano quel terzo <lb/>stato, in cui vedemmo passar finalmente il bambino, dopo le prime <lb/>platoniche illusioni e i primi aristotelici delirii; lo stato in cui l'uomo <lb/>incomincia, per il sincero uso de'sensi, a pigliare stabile possesso <lb/>del mondo. </s>

<s>Su questi che sono i naturali e legittimi iniziatori <lb/>del metodo di osservazione, giova intrattenere alquanto il nostro <lb/>discorso. </s></p><p type="main">

<s>Nei primi palpiti del nostro risorgimento nazionale, quando <lb/>l'Italia si sentiva potentemente convenire in un animo solo, e in <lb/>un solo intendimento, si rivolse, con pi&ugrave; desideroso amore che mai, <lb/>a quell'uomo di carattere fiero e generoso, che pi&ugrave; al vivo la rap&shy;<lb/>presentava di ogni altro Fu allora che s'incominci&ograve; a magnificare <lb/>e a superesaltare i meriti di lui, cosicch&egrave; non si lasci&ograve; indietro arte <lb/>n&egrave; scienza, di cui non si predicasse Dante per gran precursore. </s>

<s><lb/>Lo zelo degli animi e la leggerezza degl'ingegni hanno spinto ora&shy;<lb/>mai l'esagerazione a tal punto, che il severo tribunale della critica <lb/>ha da sentenziar molte cose contro a loro, ed &egrave; rimasto a quel tri&shy;<lb/>bunale il debito di ridur dentro i termini del vero ogni eccesso <lb/>inconsiderato. </s></p><p type="main">

<s>Gli antichi furono, nell'ammirazione dell'Alighieri, assai pi&ugrave; <lb/>temperati, e perch&egrave; nella temperanza consiste la verit&agrave;, lo amarono <lb/>perci&ograve; e lo intesero molto meglio di noi. </s>

<s>Una delle prime e pi&ugrave; <lb/>rilevanti qualit&agrave; che distinguono l'ingegno dantesco &egrave; l'armonia: <lb/>armonia di numeri, che risuona nel verso, simmetria di linee, a <lb/>regola delle quali &egrave; architettato il divino Poema. </s>

<s>Il Landino e il <lb/>Vellutello, i due pi&ugrave; antichi e rinomati commentatori, non trascu&shy;<lb/>rano di avvertire come il teatro, in cui si rappresenta l'infernale <lb/>tragedia, sia stato prima cos&igrave; ben compassato dalla mente geome&shy;<lb/>trica del Poeta, che tutto procede e corrisponde a una preordinata <pb xlink:href="020/01/088.jpg" pagenum="69"/>misura. </s>

<s>Quale per&ograve; si fosse questa misura cadde in controversia <lb/>fra il Landino, che sosteneva l'opinione di Antonio Manetti, e il Vel&shy;<lb/>lutello, che seguiva un'opinione alquanto diversa. </s>

<s>Baccio Valori, <lb/>consolo dell'Accademia fiorentina, dette poi a decidere la contro&shy;<lb/>versia a Galileo, ci&ograve; che egli fece in due lezioni accademiche, pub&shy;<lb/>blicate nel 1855 da Ottavio Gigli, sentenziando in favor del Manetti. </s></p><p type="main">

<s>Se la Conca infernale e il Monte purgatorio dimostrano in Dante <lb/>una gran perizia di arte, diremo cos&igrave;, topografica, il gran Pano&shy;<lb/>rama del Paradiso attesta che egli doveva essere esercitatissimo <lb/>ne'calcoli dell'astronomia. </s>

<s>La distanza de'pianeti dalla Terra, le <lb/>loro grandezze relative, le paralassi del Sole e della Luna, tutto ci&ograve; <lb/>insomma che poteva servire a que'calcoli di fondamento, &egrave; de&shy;<lb/>sunto, com'appar dal <emph type="italics"/>Convito,<emph.end type="italics"/> da Tolomeo, da Alfagrano e da si&shy;<lb/>mili altri autori di opere astronomiche, delle quali d&agrave; prova il <lb/>Nostro di essere massimamente erudito. </s>

<s>Su tali dati poi, qualunque <lb/>ne sia la certezza, i calcoli astronomici danteschi son condotti con <lb/>tal matematico rigore, che noi pi&ugrave; volte, per nostro giovanile eser&shy;<lb/>cizio, ci siam provati a ritesserli e gli abbiamo trovati riscontrar <lb/>sempre, con maraviglioso diletto. </s></p><p type="main">

<s>Che l'Alighieri si fosse accorto del sonno delle piante, e avesse <lb/>riconosciuto la causa dell'ascensione della linfa su per i vasi; che <lb/>il velocitarsi delle acque correnti l'attribuisse alla pressione degli <lb/>strati superiori; che ne'condensamenti e nelle dilatazioni dell'aria <lb/>prodotta dal calor del sole riconoscesse l'origine dei venti; che i <lb/>vapori acquosi disseminati nell'aria, condensati dal freddo, tornino <lb/>in pioggia: queste e simili altre cose che vanno a ripescare a gara <lb/>qua e l&agrave; pel Poema sacro i dantisti, son senza dubbio esagerazioni, <lb/>specialmente se si vogliono intendere quelle parole nel preciso si&shy;<lb/>gnificato scientifico de'moderni; son conati di farfallette, che in&shy;<lb/>tendono a sollevare pi&ugrave; in alto che mai un gigante col leggiero <lb/>tremolare delle ali. </s></p><p type="main">

<s>Il vero si &egrave; che il Poeta riassume tutta la scienza de'suoi <lb/>tempi, e la commenta e la condensa ne'suoi splendidi versi, na&shy;<lb/>scondendola talvolta cos&igrave; fra le loro pieghe, che occhio poco esperto <lb/>non se ne accorge. </s>

<s>Un esempio di quei commenti si pu&ograve; citare, <lb/>nel XV canto del Purgatorio, dalle terzine 6 e 7, nelle quali si <lb/>rendono compiute le leggi della Calottrica, soggiungendo che il rag&shy;<lb/>gio d'incidenza e quello di riflessione si ritrovano in un medesimo <lb/>piano perpendicolare alla superficie riflettente. </s></p><p type="main">

<s>Dell'ardito modo come il grande artefice del verso toscano sa-<pb xlink:href="020/01/089.jpg" pagenum="70"/>pesse condensare, e quasi trafugare una proposizione di scienza di&shy;<lb/>mostrata, in un semplice inciso, molti si potrebbero recare esempi, <lb/>de'quali nonostante pu&ograve; bastare uno solo, che si toglie dalla t. </s>

<s>17 <lb/>del XII canto del Paradiso. </s>

<s>Per la <emph type="italics"/>lunga foga<emph.end type="italics"/> i commentatori <lb/>tutti intendono la distanza del sole nel parallelo di longitudine, <lb/>ma &egrave; chiaro che dee intendersi della lunga foga del mare, per cui, <lb/>a cagione della convessit&agrave; della superficie delle acque, si nasconde <lb/>la vista delle cose lontane. </s>

<s>Ecco in due parole risoluta una que&shy;<lb/>stione, che dette occasione fra'dotti di que'tempi a tante contro&shy;<lb/>versie; Questione che Dante stesso tratt&ograve; in Verona, il d&igrave; 20 di <lb/>Gennaio 1320, in una eruditissima dissertazione latina. </s></p><p type="main">

<s>Del resto, se il gran Vate pieno di tutta scienza, non precorse <lb/>i tempi di Galileo, con nessuna importante scoperta, prepar&ograve; senza <lb/>dubbio dalla lontana quel sicuro metodo di osservare la Natura, <lb/>che fu poi fecondo di ogni pi&ugrave; bella e pi&ugrave; nuova scoperta. </s>

<s>Se nulla <lb/>scopri di nuovo nella fisiologia delle piante, pure attentamente ne <lb/>osserv&ograve; i fiori e le foglie, e ne descrisse i moti prodotti dalla luce <lb/>e dal calore. </s>

<s>Se non pose i fondamenti all'Idraulica, present&igrave; pure <lb/>in qualche modo, che le acque stesse sottostavano a una legge, in <lb/>quel loro correre apparentemente scomposto, e se va ripetendo le <lb/>viete dottrine aristoteliche intorno a molti fatti di Meteorologia, <lb/>pur gli osserva e gli descrive, non accomodandoli alla sua propria <lb/>ragione, ma ricevendoli tali e quali glieli porge sotto gli occhi la <lb/>Natura. </s></p><p type="main">

<s>Da leggere questo gran Libro della Natura, forse troppo fu <lb/>distratto l'Alighieri dalla lettura de'libri dei filosofi. </s>

<s>Ma ecco suc&shy;<lb/>cedere a lui un altro grande spirito italiano, a cui la Natura stessa <lb/>ampiamente si rivel&ograve; squadernandogli innanzi agli occhi il volume <lb/>del Mondo Universo. </s>

<s>Egli &egrave; &igrave;l gran Cristoforo Colombo, e nessuno <lb/>meglio dell'ardito navigator genovese potrebbe stare a lato al su&shy;<lb/>blime Poeta fiorentino. </s>

<s>Ma prima di parlar di lui, che ebbe la Na&shy;<lb/>tura per solo e immediato Maestro, dobbiamo trattenerci sopra un'al&shy;<lb/>tra grande figura d'uomo, a cui fu maestra la Natura stessa per <lb/>mezzo dell'arte. </s></p><p type="main">

<s>Leon Battista Alberti &egrave; costui, nato, come l'Alighieri, d'illustre <lb/>e antica famiglia fiorentina e vissuto nel secolo posteriore a quello <lb/>del Poeta, dal 1404 al 1485. Informato alle scienze dagli insegna&shy;<lb/>menti delle scuole, pi&ugrave; forse dal proprio genio che dalle consue&shy;<lb/>tudini dei tempi, fu portato da giovane a secondare i placiti della <lb/>Filosofia platonica, la quale sodisfaceva, meglio della peripatetica, <pb xlink:href="020/01/090.jpg" pagenum="71"/>agl'ingegni meditativi. </s>

<s>Egli perci&ograve; si dette allo studio delle mate&shy;<lb/>matiche, applicando queste discipline alle arti, che posson meglio <lb/>servire agli usi della vita e a sodisfarne ai bisogni. </s>

<s>Ma l'Alberti, <lb/>indulgendo al genio proprio dei giovani, tien pi&ugrave; spesso dietro e <lb/>vagheggia le curiosit&agrave; e gli spettacoli, informato da quello spirito <lb/>del platonismo, che, se scende talvolta a implicarsi ne'fatti parti&shy;<lb/>colari della Natura, non gli riguarda altrimenti che come scherzi. </s>

<s><lb/>Il titolo di <emph type="italics"/>Ludi matematici<emph.end type="italics"/> dato dall'Autore a un'operetta, nella <lb/>quale &egrave; la Geometria applicata all'altimetria, alla topografia, alla <lb/>gnomonica, alla meccanica e a simili altre discipline, per s&egrave; dice <lb/>assai, ma pi&ugrave; efficacemente a noi sembra che di ci&ograve; facciano prova <lb/>quelle cos&igrave; dette <emph type="italics"/>Dimostrazioni,<emph.end type="italics"/> le quali niente altro eran poi, se <lb/>non che spettacoli ottici, o come Leon Battista stesso gli chiamava <lb/><emph type="italics"/>Miracoli della Pittura.<emph.end type="italics"/> Con queste Dimostrazioni spettacolose e con <lb/>questi Miracoli racconta l'Autore stesso d'essersi ricreato pi&ugrave; volte <lb/>in Roma insieme coi suoi compagni. </s>

<s>Di cos&igrave; fatte Dimostrazioni <lb/>nessuno sa dirci nulla di particolare, da quell'Anonimo biografo in <lb/>fuori contemporaneo dell'Alberti, la scrittura del quale fu raccolta <lb/>e pubblicata dal Muratori. </s>

<s>Da essa chiaramente si rileva in che <lb/>propriamente consistessero quelle Albertiane Dimostrazioni. </s>

<s>Ma per&shy;<lb/>ch&egrave; oramai i ciechi ammiratori del grande artista si sono fitti in <lb/>testa non essere quelle cos&igrave; fatte Dimostrazioni altro che le stesse <lb/>ottiche rappresentanze degli oggetti sul fondo di una camera oscura, <lb/>con manifesta intenzione di dare al loro Autore la precedenza su <lb/>Leonardo e sul Porta; si son ridotti a dire che le parole del Bio&shy;<lb/>grafo anonimo non son troppo chiare. </s>

<s>Ma chiarissime sembrano a <lb/>noi, e siamo certi che tali pur sembreranno agli intelligenti e im&shy;<lb/>parziali, che, dopo un'attenta lettura, concluderanno come i giochi <lb/>ottici dell'Alberti consistevano nel contraffare e trasformare le im&shy;<lb/>magini per via di colori artificiali e di artificiali riflessioni di spec&shy;<lb/>chi, mostrandole agli spettatori curiosi proiettate sulla parete di una <lb/>camera oscura. </s>

<s>L'apparecchio ottico dunque dell'Alberti era cosa <lb/>pi&ugrave; artificiosa e applicata ad uso un po'diverso dallo strumento <lb/>del Porta. </s></p><p type="main">

<s>Nel libro insomma dei Ludi, e in quello che si pu&ograve; chiamar <lb/>Magia delle Dimostrazioni, come in altre operette, a cui piace a <lb/>noi di dare il titolo di giovanili o minori, troppo il nostro Autore <lb/>si compiace di quella curiosit&agrave;, che &egrave; sodisfatta, non dall'esser veri <lb/>i fatti della Natura, ma dall'apparir nuovi e maravigliosi. </s>

<s>Il libro <lb/>della Prospettiva, pubblicato nel IV Tomo delle opere volgari da <pb xlink:href="020/01/091.jpg" pagenum="72"/>Anicio Bonucci, non &egrave; pi&ugrave; che un commentario assai magro del&shy;<lb/>l'Ottica di Euclide, e tra que'Ludi stessi, che si leggono in fine di <lb/>questo Tomo, molti son quelli che si risentono de'difetti notati dal <lb/>Sagredo ne'Ludi del Porta. </s>

<s>Anco l'VIII, che &egrave; del misurare la <lb/>profondit&agrave; di qualunque mare, subodorato da Silvio Belli e pub&shy;<lb/>blicato nel 1565 dai manoscritti albertiani, ha il difetto di riposar <lb/>sul principio dell'equabilit&agrave; del moto de'gravi cadenti in mezzo al&shy;<lb/>l'acqua, senza che l'Autore cerchi di assicurarsene in qualche modo, <lb/>per via dell'esperienza. </s>

<s>&Egrave; vero che l'esperienze dell'Oliva fatta di&shy;<lb/>poi nell'Accademia del Cimento parvero essere favorevoli al prin&shy;<lb/>cipio, dall'Alberti ammesso per vero, ma il Borelli poco dopo, nella <lb/>propos. </s>

<s>246. <emph type="italics"/>De motion. </s>

<s>natur.,<emph.end type="italics"/> dimostr&ograve; che la discesa da gravi e <lb/>l'ascesa de'galleggianti erano velocitate, confermando le teorie con <lb/>isperimenti ingegnosi. </s></p><p type="main">

<s>Venne tempo per&ograve; che, lasciata la curiosit&agrave; delle cose nuove, <lb/>e la leggerezza degli spettacoli, si rivolse l'Alberti tutto alla Natura, <lb/>ed essa invoc&ograve; ed elesse per sua principale Maestra. </s>

<s>La nuova vo&shy;<lb/>cazione incominci&ograve; dallo studio d'imitare coll'arte quella simmetria <lb/>ed eleganza di forma, che ella &egrave; solita dare alla fabbrica di tutte <lb/>le cose mondane. </s>

<s>Leon Battista vien cos&igrave; a farsi autore di Archi&shy;<lb/>tettura, non imitando servilmente, ma rinnovellando fibre e dando <lb/>altra forma di membra agli spiriti dell'antico Vitruvio. </s>

<s>Ecco l'opera <lb/>dove propriamente il Nostro investiga le occulte cause, scioglie <lb/>questioni di fatti naturali e inventa strumenti facendo uso di quel&shy;<lb/>l'arte, e proseguendo quello stesso metodo sperimentale, di cui il <lb/>regolare istituto dovea stabilirsi un secolo e mezzo dopo. </s>

<s>Lo studio <lb/>intorno all'origine delle fonti e alle scaturigini delle acque, attri&shy;<lb/>buite dal Nostro Autore all'umidit&agrave; delle pioggie e delle nevi pe&shy;<lb/>netrate nei crepacci e imbevute dai pori della terra, lo conduce <lb/>impensatamente a fare una nuova esperienza, e ad applicarla alla <lb/>costruzione di uno strumento, che egli offre qual primizia alla Me&shy;<lb/>teorologia &ldquo; Noi abbiamo provato, egli scrive, che una spugna di&shy;<lb/>venta umida per la umidit&agrave; dell'aria e di qui caviamo una regola <lb/>da pesare, colla quale noi pesiamo quanto siano gravi e quanto <lb/>secchi i venti e l'aria &rdquo;. </s></p><p type="main">

<s>Lo studio scientifico e sperimentale dei fatti meteorologici, che <lb/>l'Alberti inizi&ograve; colla invenzione dell'Igrometro, rimase cos&igrave; profon&shy;<lb/>damente impresso d'un tal qual carattere di nazionalit&agrave;, che la Me&shy;<lb/>teorologia dur&ograve; ad essere una scienza di special cultura italiana, <lb/>anco quando ne incominciarono a riconoscere l'importanza e a darvi <pb xlink:href="020/01/092.jpg" pagenum="73"/>opera efficacemente gli scienziati di Europa. </s>

<s>Ma a confermarle quel <lb/>carattere, con pi&ugrave; profonda impressione che mai, confer&igrave; quel Cri&shy;<lb/>stoforo Colombo, intorno a cui dianzi interrompemmo il discorso. </s></p><p type="main">

<s>Il genio di osservare con quasi religiosa venerazione i fatti <lb/>della Natura, che egli ora sperimentava in s&egrave; dolcemente benefici, <lb/>ora potentemente tremendi, si rivela da quel Giornale, di cui parla <lb/>Ferdinando, nel cap. </s>

<s>XVI, della Vita che scrisse di suo padre. </s>

<s>In <lb/>quel giornale il Discopritore del Nuovo mondo andava via via no&shy;<lb/>tando tutto quel che gli occorreva ad osservare e a considerare di <lb/>pi&ugrave; memorabile. </s>

<s>&ldquo; Fu diligentissimo l'Ammiraglio, dice ivi il bio&shy;<lb/>grafo, a scrivere di giorno in giorno minutamente tutto quello che <lb/>succedeva nel viaggio, specificando i venti che soffiavano, quanto <lb/>viaggio egli facea con ciascuno, e con quali vele e correnti, e quali <lb/>cose per la via egli vedeva, uccelli o pesci, od altri cos&igrave; fatti segni &rdquo;. </s></p><p type="main">

<s>L'Humboldt, che amorosamente e da quel grande scienziato <lb/>che egli era, prese ad esaminare un tal giornale, rest&ograve; maravigliato <lb/>della copia delle osservazioni, e dell'acume, con cui moltissimi e <lb/>varii fatti naturali vi sono investigati. </s>

<s>La direzione dei venti tropi&shy;<lb/>cali da occidente in oriente, per cui nello stesso verso &egrave; sospinta <lb/>la gran corrente marina, vi si trova per la prima volta diligente&shy;<lb/>mente descritta; vi &egrave; notata l'efficacia, che ha il verde fogliame delle <lb/>foreste di condensare i vapori acquosi dell'aria, facendoli tornare <lb/>in pioggia. </s>

<s>Vi &egrave; assegnata l'altezza dell'aria, a cui sono limitati i vari <lb/>e pi&ugrave; consueti fatti meteorologici che avvengono in essa, e vi son <lb/>riconosciuti i pi&ugrave; notabili effetti, che il calore del sole produce sul&shy;<lb/>l'Oceano e sull'ammosfera. </s></p><p type="main">

<s>Il medesimo Humboldt non cessa di far le meraviglie e di <lb/>magnificare una osservazione importantissima allo studio della nuova <lb/>Geologia; osservazione che il Colombo stesso lasci&ograve; fra le molte al&shy;<lb/>tre registrata nel suo Giornale. </s>

<s>L'osservazione fatta dal nostro in&shy;<lb/>signe Navigatore, nel suo primo viaggio, &egrave; quella del vedere vege&shy;<lb/>tare insieme e pacificamente convivere nell'isola di Cuba, conifore <lb/>e palme. </s>

<s>E perch&egrave; l'osservazione che pare ovvia si giudichi come <lb/>ella dovesse essere fatta con sottile intendimento scientifico, giova <lb/>notare che il nostro Botanico del secolo XV aveva tanto tempo <lb/>prima dell'Heritier riconosciuto che i <emph type="italics"/>podocarpi<emph.end type="italics"/> hanno altri carat&shy;<lb/>teri, per cui si distinguono dagli <emph type="italics"/>abietini.<emph.end type="italics"/></s></p><p type="main">

<s>Quanto poi l'Alunno della Natura, sapesse, nello studiare le <lb/>ammirande opere di lei, congiungere alle osservazioni passive la <lb/>sagace attivit&agrave; delle esperienze, si dimostra per quel che egli os-<pb xlink:href="020/01/093.jpg" pagenum="74"/>serv&ograve;, speriment&ograve; e specul&ograve; intorno alle propriet&agrave; naturali e agli <lb/>effetti della calamita. </s>

<s>La variazione della declinazione, al variare <lb/>delle latitudini, fu diligentemente osservata da lui, e a lui si deve <lb/>il primo concetto, bench&egrave; poi in pratica riuscisse inefficace, di ser&shy;<lb/>virsi dell'ago magnetico a risolvere l'importantissimo problema delle <lb/>longitudini. </s></p><p type="main">

<s>Lo spirito di Cristoforo Colombo si trasfuse poi negli altri na&shy;<lb/>vigatori, che gli successero, specialmente italiani, i quali con rive&shy;<lb/>rente amore, leggendo nel cielo, nel mare e nella terra le opere <lb/>ammirande della Natura, seppero investigarne il segreto magistero, <lb/>meglio di tanti filosofi non dediti a leggere altro che i libri. </s>

<s>Ame&shy;<lb/>rigo Vespucci fu il primo a proporre i metodi astronomici per tro&shy;<lb/>vare le longitudini; metodi che rimasero unicamente efficaci negli <lb/>usi dei navigatori, specialmente da poi che Giovanni da Empoli e <lb/>Filippo Sassetti ebbero sperimentato che i gradi della declinazione <lb/>magnetica non serbano alcuna regola di proporzione coi gradi dei <lb/>meridiani. </s></p><p type="main">

<s><emph type="center"/>X.<emph.end type="center"/></s></p><p type="main">

<s>Fra coloro che a osservare diligentemente e a investigare le <lb/>cause degli effetti naturali vi furono rivolti dall'esercizio dell'arte, <lb/>vuol essere commemorato principale fra tutti Leonardo da Vinci. </s>

<s><lb/>L'ingegno perci&ograve; del figliuolo di Ser Piero, e la speranza dei frutti <lb/>che si vedranno raccolti da lui nel campo delle scienze naturali, <lb/>non in altro si potranno meglio conoscere, n&egrave; da altro pi&ugrave; sicura&shy;<lb/>mente indovinare, che da quelle opere d'arte condotte da lui, e <lb/>nelle quali ritrova la Natura, con maravigliosa rassomiglianza, effi&shy;<lb/>giato il suo volto. </s>

<s>Chi contempla, nel cartone di Adamo e di Eva, <lb/>lumeggiato di biacca quel praticello verdeggiante di un infinita <lb/>sorta di erbe, fra le quali vanno pascendo varie specie di animali, <lb/>o vi stanno a loro diletto; chi osserva in quel fico lo scortar delle <lb/>foglie e la veduta dei rami, e in que'palmizi le nervature che <lb/>s'aprono a formare la rotondit&agrave; delle ruote, e le sottoposte vena&shy;<lb/>ture e la minuta peluria dell'epidermide, dice: colui che ha fatto <lb/>un tal lavoro &egrave; senza dubbio o ha grande attitudine a diventare <lb/>un zoologo, un botanico. </s></p><pb xlink:href="020/01/094.jpg" pagenum="75"/><p type="main">

<s>Chi pon mente a que'nudi, che nelle varie attitudini occorrono <lb/>a vedere per questi dipinti e per questi disegni; a quel gruppo di <lb/>cavalli e di cavalieri, che nella storia di Niccol&ograve; Piccinino si con&shy;<lb/>tendono rabbiosamente una bandiera, e vede con qual verit&agrave; sono <lb/>disegnate le masse muscolari, di cui si seguono con l'occhio nei <lb/>solchi le testure delle fibre e i complicati andamenti; dice: costui <lb/>&egrave; certamente maestro d'Anatomia descrittiva e d'Anatomia compa&shy;<lb/>rata. </s>

<s>Ma chi guarda nel ritratto di Mona Lisa que'lustri e quegli <lb/>acquitrini degli occhi, quei pori della pelle nelle guance e nel <lb/>volto, e la peluria leggerissima e delicata che n'esce, soggiunge, <lb/>non dover essere costui contento all'anatomia superficiale, ma dover <lb/>esser di pi&ugrave; penetrato addentro a indagarne l'istologia. </s></p><p type="main">

<s>Chi poi non guarda solamente con gli occhi, ma considera con <lb/>l'intelletto, avvedendosi bene che in que'volti son cos&igrave; vivamente <lb/>espressi gli interiori pensieri e le passioni e gli affetti, conclude <lb/>che l'Artefice deve essere entrato addentro a speculare le segrete <lb/>cause e gli organi, per cui l'interiore spirito si rivela al di fuori. </s>

<s><lb/>Il pittore da Vinci insomma si riconosce nelle opere sue per uno <lb/>che ha sperimentato e ha speculato, o che almeno ha grandissima <lb/>attitudine a sperimentare e a speculare intorno a ogni sorta di fatti <lb/>naturali. </s>

<s>E cos&igrave; &egrave; veramente come lo attestano i documenti-che ci <lb/>son rimasti di lui. </s></p><p type="main">

<s>Cos&igrave; fatti documenti, che non potrebbero essere per verit&agrave; pi&ugrave; <lb/>autentici, consistono nelle stesse carte di Leonardo scritte, per uno <lb/>de'soliti capricci degli artisti, alla rovescia. </s>

<s>I biografi ce lo dipingono <lb/>con un lapis e un libretto pendenti dalla cintola, ad uso dei cos&igrave; <lb/>detti taccuini moderni, dov'egli andava notando tutto ci&ograve; che gli <lb/>occorreva di osservare, di sperimentare o di speculare via via. </s>

<s><lb/>Cos&igrave; fatti libretti, che si empivano rapidamente, vennero, in parte <lb/>dall'Autore stesso, e in parte dagli eredi di lui, in qualche modo <lb/>ordinati e rilegati in volumi, le prime vicende sub&igrave;te dai quali son <lb/>narrate in quel documento, che da pag. </s>

<s>130-33 si legge nelle <emph type="italics"/>Me&shy;<lb/>morie storiche<emph.end type="italics"/> dell'Amoretti, (Milano, 1804). Per quel che riguarda <lb/>poi le ultime vicende, si sa come dalla Biblioteca Ambrosiana, fos&shy;<lb/>sero quelle preziose carte rapite e trasportate a Parigi, dove a nostro <lb/>dispetto rimangono tuttavia. </s></p><p type="main">

<s>Giorgio Vasari, del contenuto in quei volumi accenn&ograve; a qual&shy;<lb/>che cosa, non concernente per&ograve; se non l'arte. </s>

<s>Per quel che s'ap&shy;<lb/>partiene alla scienza, si content&ograve; di dire che Leonardo &ldquo; fra gli <lb/>altri tanti suoi capricci ebbe anco quello che, filosofando delle cose <pb xlink:href="020/01/095.jpg" pagenum="76"/>naturali, attese a intendere le propriet&agrave; dell'erbe, continuando ed <lb/>osservando il moto del cielo, il corso della luna e gli andamenti <lb/>del sole &rdquo;. </s>

<s>Anche l'Oltrocchi, bibliotecario dell'Ambrosiana, che <lb/>perci&ograve; ebbe agio di consultare i manoscritti vinciani, mentre che <lb/>ancora erano ivi esistenti, non si cur&ograve; di trascriverne e di com&shy;<lb/>mentarne, se non solo quelle parti che riguardano le arti del <lb/>disegno. </s></p><p type="main">

<s>Il primo che rivolgesse l'attenzione alle preziose note, per leg&shy;<lb/>gervi ci&ograve; che ne concerne la scienza, fu Giovan Battista Venturi, <lb/>in quel tempo che soggiornava a Parigi, dove scrisse e nel 1797 <lb/>pubblic&ograve; quel suo celebre <emph type="italics"/>Essai,<emph.end type="italics"/> verso cui si rivolsero e da cui <lb/>presero l'inspirazione tutti quegli italiani, che incominciarono allora <lb/>e seguitano tuttavia a magnificare l'ingegno scientifico di Leonardo. </s>

<s><lb/>Il Venturi fece senza dubbio opera pia verso la patria, per cui con&shy;<lb/>viene che gliene professiamo la gratitudine dovuta. </s>

<s>Ma pi&ugrave; grati ci <lb/>sentiremmo all'illustre fisico modanese, se le parole almeno ce le <lb/>avesse trascritte nella favella che risuona dolcemente ancora sul <lb/>labbro de'villici da Vinci, e pi&ugrave; che mai grata gli sarebbe la sto&shy;<lb/>ria, se interpretando i concetti scientifici del suo Autore, non ci <lb/>avesse inteso spesso una cosa per un'altra, o non avesse intraveduto <lb/>talvolta nelle parole espresso ci&ograve; che veramente non ci era. </s></p><p type="main">

<s>Nel 1840, Guglielmo Libri apre il secondo libro della sua <emph type="italics"/>Hi&shy;<lb/>stoire des sciences mathematiques en Italie,<emph.end type="italics"/> col trattar di Leonardo <lb/>da Vinci, i manoscritti del quale dice che non erano stati ancora <lb/>seriamente studiati. </s>

<s>Egli poi gli descrive minutamente, e prolissa&shy;<lb/>mente ivi si studia di annoverarne i soggetti varii toccati, e di <lb/>porre in rilievo la novit&agrave; de'concetti e la importanza delle in&shy;<lb/>venzioni. </s>

<s>Dei quali concetti pi&ugrave; notabili e delle quali invenzioni, <lb/>accioch&egrave; possano i lettori averne qualche saggio, trascrive alcuni <lb/>passi dai vari manoscritti e gli pon sott'occhio in quelle <emph type="italics"/>XXI Notes<emph.end type="italics"/><lb/>apposte in calce al III Tomo della citata <emph type="italics"/>Histoire.<emph.end type="italics"/> Eppure si pos&shy;<lb/>sono ancora, dop'aver letto le prime 58 pagine del <emph type="italics"/>livre second,<emph.end type="italics"/> e <lb/>le <emph type="italics"/>XXI Notes,<emph.end type="italics"/> ripetere al Libri le sue stesse parole, che egli pro&shy;<lb/>nunziava dop'aver dato il suo giudizio sull'<emph type="italics"/>Essai<emph.end type="italics"/> del Venturi: &ldquo; Or <lb/>ces manuscrits n'ont jamais &eacute;t&eacute; serieusement &eacute;tudi&eacute;s &rdquo; (Paris 1840, <lb/>Tome III, pag. </s>

<s>39). A studiarli seriamente poi pi&ugrave; tardi incomin&shy;<lb/>ciarono due stranieri, Carlo Ravaisson-Mollien a Parigi, e Giovan <lb/>Paulo Richter a Londra. </s>

<s>Gli italiani che van buccinando il nome <lb/>di Leonardo con tuba s&igrave; sonora, non hanno dato, fin qui, opera <lb/>che a'illustrare alcuni disegni scelti dal Codice Atlantico, pub-<pb xlink:href="020/01/096.jpg" pagenum="77"/>blicati in XXIV tavole litografate, per modo di saggio, in Milano <lb/>nel 1872: lavoro non scientifico, ma accademico, e benissimo atto <lb/>a secondare il genio de'convenuti a una festa. </s></p><p type="main">

<s>Toccheremo qualche cosa pi&ugrave; qua delle pubblicazioni fatte dai <lb/>due benemeriti stranieri: quel che ora per&ograve; pi&ugrave; preme, &egrave; di offerir <lb/>qualche esempio delle osservazioni naturali e delle speculazioni di <lb/><figure id="id.020.01.096.1.jpg" xlink:href="020/01/096/1.jpg"/><lb/>Leonardo, che quasi promesseci nei dipinti, si trovano poi fedel&shy;<lb/>mente osservate nei manoscritti. </s></p><p type="main">

<s>Dicemmo che il cartone, il quale doveva servire al dipinto di <lb/>quelle portiere, da eseguirsi pel re di Portogallo, rivelava nell'ar&shy;<lb/>tefice un botanico squisito, e soggiungemmo potersi argomentare <lb/>da tutto insieme che l'artefice stesso non dovess'essere un semplice <pb xlink:href="020/01/097.jpg" pagenum="78"/>osservatore, ma un filosofante delle propriet&agrave; naturali dell'erbe. </s>

<s><lb/>Ecco infatti una nota dai Manoscritti, nella quale apparisce che ve&shy;<lb/>ramente Leonardo attese a quell'ordine simmetrico e vario, nelle <lb/>varie specie di piante, che le foglie tengono nel disporsi intorno <lb/>all'asse del ramo, e che i moderni appellano col nome di <emph type="italics"/>fillotassi.<emph.end type="italics"/><lb/>&ldquo; Tale &egrave; il nascimento, egli dice, delle ramificazioni delle piante <lb/>sopra i lor rami principali, qual &egrave; quello del nascimento delle fo&shy;<lb/>glie sopra i ramicoli del medesimo anno di esse foglie, le quali <lb/>foglie hanno quattro modi di procedere l'una pi&ugrave; alta che l'altra. </s>

<s><lb/>Il primo pi&ugrave; universale &egrave; che sempre la sesta di sopra nasce sopra <lb/>la sesta di sotto: e il secondo &egrave; che le due terze di sopra son <lb/>sempre le due terze di sotto; e il terzo modo &egrave; che la terza di <lb/>sopra &egrave; sopra la terza di sotto. </s>

<s>&rdquo; (Richter, Londra, 1883, T.I, pag. </s>

<s>211). </s></p><p type="main">

<s>Che se di qui non trasparisce altro pi&ugrave; che il semplice osser&shy;<lb/>vatore, la seguente nota ci rivela il filosofo: &ldquo; Sempre la foglia <lb/>volge il suo diritto inverso il cielo acci&ograve; possa meglio ricevere con <lb/>tutta la sua superficie la rugiada che con lento moto discende dal&shy;<lb/>l'aria, e tali foglie sono in modo compartite sopra le loro piante, <lb/>che l'una occupa l'altra il men che sia possibile, coll'interzarsi <lb/>l'una sopra dell'altra, come si vede fare all'edera che copre li <lb/>muri; e tale intrecciamento serve a due cose: cio&egrave; al lasciare l'in&shy;<lb/>tervallo che l'aria e il sole possa penetrare in fra loro e che le <lb/>goccie che caggiono dalla prima foglia possan cadere sopra la quarta <lb/>e la sesta degli altri alberi. </s>

<s>&rdquo; (ivi, pag. </s>

<s>214). </s></p><p type="main">

<s>L'osservazione, che port&ograve; Leonardo sulla realt&agrave; dei modelli, <lb/>per ritrarre al vivo la carne degli uomini, gli serv&igrave; d'occasione a <lb/>coltivar lo studio di quell'altra fra le scienze naturali, che &egrave; l'Ana&shy;<lb/>tomia. </s>

<s>Quali aiuti gli venissero intorno a ci&ograve; da Marcantonio Della <lb/>Torre non &egrave; facile definire, ma forse la perizia del sezionare di <lb/>questo, era compiuta dalla sagacia delle osservazioni e delle inda&shy;<lb/>gini dell'altro. </s>

<s>Nel dipingere un occhio s'accorge Leonardo di un <lb/>fatto assai curioso; di un fatto, che Galileo scommette non esser&shy;<lb/>vene due fra mille che l'abbiano osservato (Alb. </s>

<s>I, 394) e par che <lb/>voglia insinuar collo stesso silenzio che l'osservazione &egrave; sua, ben&shy;<lb/>ch&egrave; il Porta l'avesse descritta nella Diottrica e l'Acquapendente <lb/>avesse pubblicato com'occorresse al Sarpi di farla negli occhi dei <lb/>gatti e poi degli uomini. </s>

<s>Ma pi&ugrave; di un secolo prima del Porta e <lb/>del Sarpi avea il nostro pittore da Vinci osservato il fenomeno, e <lb/>v'avea filosofato attorno con assai retto giudizio. </s>

<s>Hanno inteso i <lb/>lettori che il fenomeno di cui si tratta &egrave; il dilatarsi e il restrin-<pb xlink:href="020/01/098.jpg" pagenum="79"/>gersi della pupilla, sotto le impressioni della varia intensit&agrave; della <lb/>luce; fenomeno che non solo fu da Leonardo materialmente osser&shy;<lb/>vato, ma altres&igrave; filosoficamente illustrato, in ordine a ci&ograve; che con&shy;<lb/>cerne la teoria della visione. </s>

<s>&ldquo; Questa nostra pupilla, ci lasci&ograve; scritto, <lb/>cresce e diminuisce secondo la chiarit&agrave; o scurit&agrave; del suo obietto, <lb/>e perch&egrave; con qualche tempo fa esso crescere o descrescere, esso <lb/>non vede cos&igrave; presto uscendo dal lume e andando all'oscuro, e <lb/>similmente dall'oscuro al luminoso, e questa cosa gi&agrave; m'ingann&ograve; <lb/>nel dipingere un occhio e di l&igrave; l'imparai. </s>

<s>&rdquo; (Ivi, pag. </s>

<s>23). </s></p><p type="main">

<s>Il curioso fatto imparato nel dipingere la pupilla, invogli&ograve; forse <lb/>Leonardo a penetrare pi&ugrave; addentro all'anatomia dell'occchio, e ad <lb/>estrarlo dal cadavere per sezionarlo. </s>

<s>In altro modo riuscirebbe assai <lb/>difficile intendere com'egli vi avesse potuto scoprir l'inversioni delle <lb/>immagini, a cui accenna nella nota seguente: &ldquo; Nessuno spazio di s&igrave; <lb/>minimo corpo penetra nell'occhio che non si volti sottosopra. </s>

<s>&rdquo; No&shy;<lb/>tabili son poi le parole, colle quali prosegue e in che si studia di <lb/>risolvere quel famoso problema, che ha tenuto gli ottici in cos&igrave; lungo <lb/>travaglio, problema che &egrave; quello del vedersi da noi le immagini <lb/>dirette, mentre sul fondo del nostro occhio son dipinte a rovescio. </s>

<s><lb/>Leonardo n'esce da par suo ammettendo un'ipotesi assai strana. </s>

<s><lb/>Professando le dottrine galeniche, secondo le quali la lente cristal&shy;<lb/>lina &egrave; la sede della visione, e ingannato forse da alcuni effetti ve&shy;<lb/>duti fare ai processi ciliari, credette che fosse a questi stessi com&shy;<lb/>messo l'ufficio di capovolgere la medesima lente cristallina, per cui <lb/>venissero cos&igrave; a raddrizzarsi le immagini degli oggetti &ldquo; e nel pe&shy;<lb/>netrare, (tali son le parole soggiunte alle precedenti citate), la spera <lb/>cristallina ancora si rivolta sottosopra e cos&igrave; ritorna diritto lo spa&shy;<lb/>zio dentro all'occhio, com'era l'obietto di fuori dell'occhio. </s>

<s>&rdquo; (ivi, <lb/>pag. </s>

<s>48). Da ci&ograve; dovette seguitar senza dubbio l'invenzione della <lb/>camera ottica e l'applicazione ch'ei ne fa alla teoria della visione, <lb/>conforme a ci&ograve; che leggesi in quell'altra nota trascritta e pubbli&shy;<lb/>cata gi&agrave; dal Venturi. </s>

<s>L'invenzione della camera oscura par dunque <lb/>certo esser cosa appartenente a Leonardo, almeno per ci&ograve; che con&shy;<lb/>cerne l'applicazione di lei alla teorica del vedere: applicazione alla <lb/>quale non poteva pensare l'Alberti, professando egli apertamente <lb/>le dottrine platoniche de'raggi visivi che escon dagli occhi, e vanno <lb/>a ricongiungersi col fuoco celeste, essendo parole espresse di lui <lb/>che la visione si porge e distende verso la cosa visibile. (Op. </s>

<s>volg. </s>

<s><lb/>Firenze, 1847, T. IV, pag. </s>

<s>100) e che il raggio della veduta esce <lb/>dall'occhio di chi riguarda. (Archit. </s>

<s>Milano, 1833, pag. </s>

<s>362). </s></p><pb xlink:href="020/01/099.jpg" pagenum="80"/><p type="main">

<s>Delle molte altre scoperte o speculazioni di Fisica, e osserva&shy;<lb/>zioni di Storia naturale, occorrer&agrave; via via di far parola per entro <lb/>ai volumi che si parano innanzi agli occhi dei nostri lettori; sco&shy;<lb/>perte che Leonardo faceva non consultando libri, ma direttamente <lb/>interrogando la stessa Natura per via dell'esperienza. </s>

<s>Che tale fosse <lb/>l'indole e il metodo seguito dall'Autore, noi lo abbiamo fin qui <lb/>argomentato dai fatti, e sono i nostri argomenti confermati dalle <lb/>stesse parole di lui, che egli scrive contro l'arroganza dei filosofi <lb/><emph type="italics"/>in libris.<emph.end type="italics"/> &ldquo; Molti mi crederanno ragionevolmente, egli nota, poter <lb/>riprendere allegando le mie prove esser contro all'antorit&agrave; di al&shy;<lb/>quanti uomini di gran riverenza appresso de'loro inesperti giudizii, <lb/>non considerando le mie cose essere nate sotto la semplice espe&shy;<lb/>rienza, la quale &egrave; maestra vera. </s>

<s>&rdquo; (Richter, ivi, pag. </s>

<s>15). </s></p><p type="main">

<s>E che veramente potesse l'esperienza, assai meglio de'libri, <lb/>condurre Leonardo alla scoperta della camera ottica, e l'osserva&shy;<lb/>zione rivelargli la fillotassi, come altres&igrave; que'molti e varii fatti na&shy;<lb/>turali, che si leggon notati qua e l&agrave; ne'suoi Manoscritti, &egrave; cosa <lb/>facilissima a comprendersi da tutti. </s>

<s>N&egrave; difficile &egrave; pure intendere <lb/>come l'osservazione stessa e la propria esperienza potessero con&shy;<lb/>durlo a scoprir quella legge fondamentale, che governa il moto <lb/>dell'acque, a cui, per la stessa via, eran giunti Frontino, i Pretori <lb/>romani, e pi&ugrave; recentemente l'Alberti; legge, dalla quale, filosofando <lb/>e sperimentando, non difficilmente si sarebbero svolti nell'ingegno <lb/>di Leonardo que'teoremi, che raccolti insieme e ordinati, compon&shy;<lb/>gono quel Trattato idraulico, il quale va sotto il nome di lui. </s></p><p type="main">

<s>Ma non sempre le note che ricorrono per i manoscritti vin&shy;<lb/>ciani versano circa a soggetti di Fisica sperimentale, o di Storia na&shy;<lb/>turale, o di Meccanica pratica. </s>

<s>La miglior parte e pi&ugrave; importante <lb/>di quelle note contiene dimostrazioni di Meccanica razionale, alle <lb/>quali non sarebbe potuto Leonardo riuscire in qualche modo, sen&shy;<lb/>z'esservisi prima preparato con discipline e con istudii, che non <lb/>si apprendono se non dalla lettura dei libri o dalla voce dei mae&shy;<lb/>stri. </s>

<s>Luca Paciolo, amico suo, gli dovett'essere, senza dubbio, nelle <lb/>Matematiche di grande aiuto, e l'Amoretti a pag. </s>

<s>86 delle citate <lb/><emph type="italics"/>Memorie<emph.end type="italics"/> fa menzione di una scrittura del Nostro, nella quale ri&shy;<lb/>chiede l'Archimede del vescovo di Padova. </s>

<s>Per ci&ograve; a noi sembra <lb/>ragionevolissimo il credere che il Matematico di Siracusa colla let&shy;<lb/>tera morta, e il Matematico del Borgo colla parola viva, iniziassero <lb/>l'ingegno di Leonardo a intendere le proposizioni della Geometria <lb/>e al farne l'applicazione ai teoremi della Meccanica. </s></p><pb xlink:href="020/01/100.jpg" pagenum="81"/><p type="main">

<s>Bench&egrave; si ritenga da noi una tal credenza, per cosa certissima, <lb/>il veder nonostante il discepolo far cos&igrave; gran progressi nella scuola <lb/>de'due pi&ugrave; insigni Maestri di scienza matematica, di che si glorii <lb/>l'Italia, ha tanto del maraviglioso, e tanto esce fuori de'consueti <lb/>ordini della storia, che ne rimane stupefatto il nostro povero in&shy;<lb/>telletto. </s>

<s>Ci&ograve; che quell'artista seppe speculare della Scienza del moto <lb/>e per quanto largo spazio riuscisse a conquistare le incognite pro&shy;<lb/>vincie, nelle quali Galileo stabil&igrave; il suo Nuovo Regno, i lettori, a <lb/>cui baster&agrave; la pazienza di seguirci in questo lungo viaggio, lo ve&shy;<lb/>dranno bene a suo tempo. </s>

<s>S'abbatteranno, leggendo, in un Tratta&shy;<lb/>tello di <emph type="italics"/>Meccanica razionale,<emph.end type="italics"/> da noi con diligente amore compilato <lb/>da quei manoscritti vinciani, che abbiamo potuto vedere alla pub&shy;<lb/>blica luce, e che si son potuti da noi, con qualche comodit&agrave;, con&shy;<lb/>sultare. </s>

<s>Con pari amor diligente &egrave; stato pure compilato da noi quel&shy;<lb/>l'altro Trattatello d'Idraulica, che vedranno i nostri lettori inserito <lb/>a suo luogo, compendiato da quello, che per la prima volta fu <lb/>nel 1828 pubblicato in Bologna. </s>

<s>La brevit&agrave; stessa, se non il nuovo <lb/>ordine che noi ci siamo studiati di dare alle parti di quel Tratta&shy;<lb/>tello, gioveranno a porre in pi&ugrave; vivo rilievo la scienza di Leonardo, <lb/>perciocch&egrave; il compilator primo e pi&ugrave; antico di quel Trattato in&shy;<lb/>tiero, oltre ad esser trascorso in errori gravissimi materiali e for&shy;<lb/>mali, non ha usato discrezione alcuna cos&igrave; nella scelta come nel&shy;<lb/>l'ordine dei teoremi. </s></p><p type="main">

<s>Un'altra compilazione fatta allo stesso modo &egrave; pure il Trattato <lb/>della Pittura, n&egrave; sappiamo intendere come gli artisti e i letterati <lb/>lo abbiano potuto cos&igrave; confidentemente ritener per legittimo parto <lb/>del Vinci, tanto nella materia che nella forma. </s>

<s>Il sospetto ragio&shy;<lb/>vole del Venturi sarebbe confermato dal ripensare a quel carattere <lb/>incontentabile, come &egrave; il grande Artista dipinto dal Vasari, il quale <lb/>dice di lui che il cercar nell'opere eccellenza sopra eccellenza, <lb/>com'ei sempre faceva, <emph type="italics"/>era cagione che nessuna ne lasciasse asso&shy;<lb/>luta.<emph.end type="italics"/> Da un'altra parte Leonardo si confessa da s&egrave; medesimo per <lb/>uomo senza lettere, e inetto a ben dire quello che voleva trattare. <lb/></s>

<s>&ldquo; Diranno che per non avere io lettere non poterei ben dire quello <lb/>che voglio trattare. </s>

<s>Or non sanno questi che le mie cose son pi&ugrave; <lb/>da esser trattate dalla sperienza che d'altra parola, la quale fu <lb/>maestra di chi bene scrisse e cos&igrave; per maestra la, in tutti i casi, <lb/>allegher&ograve;. </s>

<s>&rdquo; (ivi, pag. </s>

<s>14). </s></p><p type="main">

<s>Sopra questi certissimi argomenti noi crediamo di potere af&shy;<lb/>fermare che Leonardo non ebbe quella pazienza o quella costanza, <pb xlink:href="020/01/101.jpg" pagenum="82"/>e diciam pure quell'arte letteraria, che si richiedeva a dar forma <lb/>di Trattato alle varie materie e a ordinarle in libri, in capitoli, in <lb/>proposizioni, come asseriscono molti. </s>

<s>Ond'&egrave; che da noi si potrebbe <lb/>facilmente mostrar l'inganno che fu preso dall'Amoretti nel &sect; XXXII <lb/>delle <emph type="italics"/>Memorie,<emph.end type="italics"/> dove annovera un lungo catalogo di Trattati, gi&agrave; <lb/>bell'e messi all'ordine da Leonardo, alcuni de'quali anco scritti <lb/>in latino; si potrebbe far ci&ograve; diciamo assai facilmente, se l'Autore <lb/>stesso non avesse dato a vedere d'essersi gi&agrave; per s&egrave; medesimo ac&shy;<lb/>corto di quell'inganno. </s>

<s>N&egrave; pi&ugrave; difficile pure sarebbe il mostrar <lb/>qual conto si debba fare e in qual significato debbono interpetrarsi <lb/>le autorevoli testimonianze di Luca Pacioli. </s></p><p type="main">

<s>Concludiamo insomma come tutto quello che &egrave; propriet&agrave; let&shy;<lb/>teraria del Nostro, si contiene in quelle note, in quegli appunti, <lb/>in quei ricordi, che ci son rimasti tuttavia manoscritti autografi <lb/>nella carte di lui. </s>

<s>La non breve vita decorsagli dal 1452 al 1519 <lb/>e la costante abitudine di nulla tralasciar d'inosservato, fa ragio&shy;<lb/>nevolmente presupporre che molti pi&ugrave; de'pervenuti infino a noi <lb/>dovessero essere i libretti vinciani, e dall'altra parte non &egrave; possi&shy;<lb/>bile che, in tanto tramestar di mani e traslocar di paesi, non an&shy;<lb/>dassero in qualche parte smarriti. </s>

<s>Pure &egrave; tanta l'eredit&agrave; scientifica <lb/>a noi trasmessa, che ce ne dovremmo contentare e pensar piuttosto <lb/>al miglior modo di usufruirla. </s></p><p type="main">

<s>Si diceva dianzi che ad usufruirla pens&ograve;, de'primi, in Francia, <lb/>il Ravaisson-Mollien, che ci dette fotografata una buona parte delle <lb/>carte vinciane sottovi trascritte le note conforme all'ortografia mo&shy;<lb/>derna, e di rincontro al testo la traduzione francese. </s>

<s>&Egrave; naturalis&shy;<lb/>simo ch'ei dovesse incontrarsi in grandissime difficolt&agrave;, s&igrave; rispetto <lb/>alla materia, s&igrave; rispetto al modo d'interpetrarla, ci&ograve; che troppo <lb/>bene apparisce dalle stesse versioni e da quegl'indici posti in fine <lb/>ai volumi, dove l'egregio uomo and&ograve; a rifugiare i commenti scien&shy;<lb/>tifici, talvolta importantissimi, ch'ei fa al testo vinciano. </s>

<s>Ma un'oc&shy;<lb/>casione insuperabile di errori &egrave; in lui, e ne'pari suoi, il non aver <lb/>senso di quel vernacolo toscano, di che fa uso nelle solitarie sue <lb/>scritture Leonardo. </s>

<s>Ci&ograve; conduce il benemerito editor parigino in <lb/>errori gravissimi, e di ci&ograve; in fine della presente parte del nostro <lb/>Discorso sottoporremo al giudizio de'nostri lettori, in nota, un <lb/>esempio. </s></p><p type="main">

<s>&Egrave; ben vero per&ograve; che ad apparecchiar l'ordinamento de'con&shy;<lb/>cetti di Leonardo, e a pubblicarli in modo che se ne possano gio&shy;<lb/>vare gli studiosi, non si richiedeva di meglio della laboriosissima <pb xlink:href="020/01/102.jpg" pagenum="83"/>opera del Parigino, che noi facciamo voto di veder presto condotta <lb/>alla sua m&egrave;ta. </s>

<s>Con tutti quei materiali alla mano si potr&agrave; allora <lb/>incominciare a costruire, e il giudizioso Architetto, fra quegli stessi <lb/>materiali di ugual sostanza e di non differente forma, sceglier&agrave; <lb/>opportunamente i migliori e lascer&agrave; indietro i disutili, per qualsi&shy;<lb/>voglia ragion di difetto che ritrovisi in essi. </s></p><p type="main">

<s>Chi attende con qualche studio ai Manoscritti vinciani, facil&shy;<lb/>mente ritrova che ora una nota, perch&egrave; l'Autore v'ha ripensato <lb/>un po'meglio, contradice a un'altra; ora il concetto che qui viene <lb/>espresso in confuso, altrove &egrave; meglio spiegato; ora &egrave; una specula&shy;<lb/>zione interrotta che poi viene ripresa e continuata, aggiungendo <lb/>qualche cosa al gi&agrave; detto, che &egrave; ripetuto sotto altra forma. </s>

<s>Qui &egrave; <lb/>trascorso un errore, e pi&ugrave; qua lo troviamo o confermato o corretto. </s>

<s><lb/>Molte volte quel che sente d'averlo espresso male, si prova a ri&shy;<lb/>dirlo un po'meglio. </s>

<s>Il non voler far uso in questi casi di una giu&shy;<lb/>diziosa scelta, &egrave; un volere stampar volumi sopra volumi per de&shy;<lb/>corarne le biblioteche, non perch&egrave; se ne giovino gli studiosi. </s></p><p type="main">

<s>Siam venuti cos&igrave; preparando le file a intessere il nostro giu&shy;<lb/>dizio intorno all'opera fatta dal Richter, il quale ha gi&agrave; dato <lb/>mano, non come il Mollien a preparare o mettere all'ordine i ma&shy;<lb/>teriali, ma a costruire. </s>

<s>Forse egli ha avuto in ci&ograve; far troppa fretta <lb/>e non avendo potuto giustamente estimare ogni pi&ugrave; minuta par&shy;<lb/>ticolarit&agrave;; non &egrave; riuscito a farne convenientemente la scelta. </s>

<s>Ma <lb/>pure ha di una scelta riconosciuto giudiziosamente il bisogno, e <lb/>poniamo che la difficile impresa non sia andata, com'asseriscono i <lb/>censori di lui, esente da gravissimi difetti; a noi par nonostante <lb/>che l'editor londinese abbia tenuta la via conveniente a chi si <lb/>dava cura di pubblicar le opere di Leonardo, per benefizio degli <lb/>studiosi. </s></p><p type="main">

<s>Alcuno ha apposto per difetto al Richter l'aver trascurati i <lb/>commenti, n&egrave; si sa di qual sorte commenti abbia inteso costui. </s>

<s><lb/>Commenti filologici, senza dubbio sarebbero stati opportuni, ma <lb/>non era in grado di farli un inglese, che anzi cade anch'egli assai <lb/>spesso negli errori, notati di sopra nel Mollien, per non aver senso <lb/>e pratica del vernacolo toscano. </s>

<s>Commenti scientifici, pi&ugrave; che op&shy;<lb/>portuni, sembrerebbero necessari, ma per farli occorrerebbe di co&shy;<lb/>noscer lo stato della scienza a'tempi di Leonardo, scienza affidata <lb/>alla viva voce dei maestri e alle carte neglette e perci&ograve; disperse <lb/>n&egrave;, per umana industria forse recuperabili. </s>

<s>Se si potessero aver <lb/>sott'occhio quei documenti, Leonardo da Vinci apparirebbe sempre <pb xlink:href="020/01/103.jpg" pagenum="84"/>un'ingegno straordinario, ma cesserebbe di rappresentarsi al nostro <lb/>giudizio sotto l'aspetto d'ingegno miracoloso, ritrovandosi che an&shy;<lb/>ch'egli ha, per legge ordinaria, dovuto soggiacere alle necessit&agrave; <lb/>delle tradizioni, a ministrar le quali gli dovevano esser soccorsi i <lb/>libri antichi e gl'insegnamenti de'suoi tempi. </s>

<s>Quella po'di luce che <lb/>poteva venirgli da cos&igrave; fatti insegnamenti era sufficiente a indirizzar <lb/>Leonardo per i sentieri del vero, a proseguir lungo i quali lo con&shy;<lb/>duceva per mano la stessa Natura, negli amati esercizi dell'arte. </s></p><p type="main">

<s><emph type="center"/>XI.<emph.end type="center"/></s></p><p type="main">

<s>Trattenendo il pensiero meditativo, cos&igrave; sopra questa maravi&shy;<lb/>gliosa figura d&igrave; Leonardo, come su quella degli altri cultori del&shy;<lb/>l'arte, sia essa l'arte del verso nell'Alighieri, sia l'arte navigatoria <lb/>nel Colombo, sia l'arte edilizia nell'Alberti, ci persuadiam facilmente <lb/>che quegli uomini singolari attesero non ad assottigliar l'ingegno <lb/>nella dialettica dei sofismi, ma a inacutire i sensi per pigliar pi&ugrave; <lb/>sicuro possesso delle cose reali. </s>

<s>L'arte navigatoria e quella della <lb/>stampa felicemente ritrovate nel medesimo tempo, eran come i due <lb/>remi maestri che a quel possesso conducevano la navicella, dentro <lb/>alla quale fa, la mente dell'uomo, da nocchiero. </s>

<s>Di qui &egrave; che in <lb/>affidarsi al mar periglioso, vollesi a quella stessa navicella rivedere <lb/>ogni testura, e far esperienza di ci&ograve; che potesse incontro all'in&shy;<lb/>sorger tempestoso dei flutti e del vento. </s>

<s>Se ci si conceda ora che <lb/>si possa, per una tal navicella, rappresentare il corpo dell'uomo, <lb/>si comprender&agrave; come la condizione dei tempi e il progredir nelle <lb/>cognizioni, dovessero portare allo studio dell'Anatomia, e di quegli <lb/>organi dei sensi in particolare, per cui l'uomo entra nel pieno e <lb/>reale possesso del mondo. </s></p><p type="main">

<s>Fino al terminar di quel secolo, in cui fu spento Leonardo, <lb/>tutto ci&ograve; che si sapeva della fabbrica del corpo umano s'appren&shy;<lb/>deva dai libri dell'antico Galeno, il quale era ai medici, come Ari&shy;<lb/>stotile ai filosofi, l'oracolo venerato degl'infallibili responsi. </s>

<s>Ma <lb/>scese dal Belgio in Italia un uomo che, colle sacrileghe mani, os&ograve; <lb/>di atterrar dagli altari quell'idolo, con audace pretensione di di&shy;<lb/>mostrare che la maggior parte di que'suoi responsi erano bugiardi. </s>

<s><lb/>Un tale uomo nativo di Bruxelles si chiamava Andrea Vesalio, il <pb xlink:href="020/01/104.jpg" pagenum="85"/>quale, eletto a professar Anatomia nello studio di Padova, sezionando <lb/>cadaveri umani e mettendo sott'occhio le parti nelle loro vere forme <lb/>naturali, le veniva sagacemente comparando alle forme stesse de&shy;<lb/>scritte da Galeno, e ad ogni passo ne scopriva un errore. </s>

<s>Additava <lb/>anco il Vesalio la fonte originaria di tali errori, ch'ei loquacemente <lb/>riconosceva nell'aver l'anatomico greco descritta non la fabbrica <lb/>del corpo dell'uomo, ma quella del bruto. </s></p><p type="main">

<s>Le religiose superstizioni pagane, per le quali si reputava atto <lb/>sacrilego lo scompaginar violentemente le membra anco ad un uomo <lb/>morto, e l'opinione che fossero similmente configurate le membra <lb/>al di dentro, com'appariscono al di fuori, negli uomini e nei bruti, <lb/>furono senza dubbio le due principali sorgenti di quegli antichi <lb/>errori, che il Vesalio era venuto a scoprire al troppo credulo mondo. </s>

<s><lb/>La scienza perci&ograve; professer&agrave; eterna gratitudine a quell'uomo, e lo <lb/>riconoscer&agrave; per primo Istitutore dell'Anatomia. </s>

<s>Ma, o fosse giova&shy;<lb/>nile baldanza o nat&igrave;o orgoglio, non serb&ograve;, nel geloso esercizio del <lb/>suo ministero, il debito modo, per cui gli si concitarono incontro <lb/>dai Galenisti inimicizie e persecuzioni s&igrave; fiere, che quelle esercitate <lb/>poi da'peripatetici contro Galileo, al paragone, sembran carezze. </s></p><p type="main">

<s>Successe al Vesalio, nello studio padovano, Realdo Colombo <lb/>di Cremona, il quale era stato gi&agrave; spettatore delle sezioni e udi&shy;<lb/>tore delle acerbe diatribe declamate dall'ardente brussellese. </s>

<s>Nel <lb/>temperato animo del nostro italiano parvero, infin da giovane, quelle <lb/>diatribe contro l'antico maestro un po'troppo esagerate, e succe&shy;<lb/>duto nella cattedra di lui non manc&ograve; di confessarle e di dare esempii <lb/>d'una critica pi&ugrave; mite e pi&ugrave; giudiziosa. </s>

<s>Il Vesalio aveva atterrate <lb/>le mura del tempio galenico, il primo, con ardimento inaudito, per <lb/>cui, mentre da una parte perseguitavasi a morte, s'esaltava, dal&shy;<lb/>l'altra, col titolo di <emph type="italics"/>divino.<emph.end type="italics"/> Il Colombo, entrato il primo per quella <lb/>breccia aperta, v'instaur&ograve; il nuovo regno dell'Anatomia descrittiva <lb/>e sperimentale, e oper&ograve; con tant'arte giudiziosa, che la violenta <lb/>conquista vesaliana prese aspetto di una successione legittima. </s></p><p type="main">

<s>Chi vuol giustamente apprezzare i meriti dell'Anatomico cre&shy;<lb/>monese, e ravvisar quella fina arte ch'egli us&ograve; per diffondere la <lb/>nuova scienza, non distruggendo con rabbioso orgoglio l'antico edi&shy;<lb/>fizio, ma correggendolo con giudiziosa industria e ampliandone la <lb/>struttura; non dee far altro che svolgere quelle splendide pagine, <lb/>che egli scrisse e intitol&ograve; <emph type="italics"/>De re anatomica,<emph.end type="italics"/> stampate nel 1559 in <lb/>Venezia dalla tipografia di Niccol&ograve; Bevilacqua. </s>

<s>A noi sembra questo <lb/>il pi&ugrave; bel libro, che in materia scientifica sia uscito fuori in quel <pb xlink:href="020/01/105.jpg" pagenum="86"/>tempo, ed &egrave; tanta la sobriet&agrave; dell'erudizione, tanta l'arte colla quale <lb/>sa nuotar fuori del gazzabuglio delle opinioni e sollevarsi alto sulla <lb/>nebbia uggiosa de'placiti delle scuole, tanta la lucidezza delle ar&shy;<lb/>gomentazioni e la oppurtunit&agrave; delle esperienze, che sembra essere <lb/>stata scritta quell'opera dopo i tempi di Galileo. </s>

<s>Se si ripensa anzi <lb/>a quella generosa e temperata franchezza, colla quale egli emenda <lb/>gli errori, in che incorsero Aristotile e Galeno e lo stesso Vesalio, <lb/>si creder&agrave; che l'Autore non iscrivesse, come Galileo stesso, in tempi <lb/>di controversie, ma nella pacifica dominazione del Metodo speri&shy;<lb/>mentale, tanto &egrave; serena la mente di Realdo Colombo nello stesso <lb/>fervoroso zelo dell'eloquente parola. </s></p><p type="main">

<s>Il primo libro anatomico del Cremonese tratta delle ossa. </s>

<s>Egli <lb/>ivi diligentemente attende a descrivere le <emph type="italics"/>epifisi,<emph.end type="italics"/> dell'utilit&agrave; delle <lb/>quali, egli dice, Galeno, d'altra parte solertissimo investigatore <lb/>della Natura, non scrisse, e ci&ograve; che pi&ugrave; fa meraviglia, non scrisse <lb/>nemmeno il Vesalio, <emph type="italics"/>quippe qui ardiret cupiditate increbili in <lb/>Galenum invehendi et eius errores adnotandi.<emph.end type="italics"/> (Da re anat. </s>

<s>edit. </s>

<s><lb/>cit. </s>

<s>pag. </s>

<s>4). Nel divisare, delle ossa una classificazione veramente <lb/>scientifica, dice di non aver seguito gli esempii n&egrave; di Galeno an&shy;<lb/>tico n&egrave; del Vesalio moderno, intorno a che tanto vivo sente il <lb/>dovere di non dilungarsi capricciosamente dall'insegnamento dei <lb/>primi maestri, che vuol, del fatto, mostrar di averne la sua buona <lb/>ragione. &ldquo; Nam licet Galenum, tamquam numen veneremur, Vesa&shy;<lb/>lioque in dissectionis arte plurimum tribuamus, ubi cum rei na&shy;<lb/>tura consentiunt: tamen cum aliquando videamus rem aliter multo <lb/>se habere ac ipsi descripserint, veritas eadem, cui magis addicti <lb/>sumus, nos coegit ab illis interdum recedere &rdquo; (ibi, pag. </s>

<s>10). </s></p><p type="main">

<s>Memoranda sentenza sulla bocca di uno scienziato, che scrive <lb/>nella prima met&agrave; del secolo XVI: io seguo, nell'investigare i fatti <lb/>della Natura, la verit&agrave;, non il maestro, e sia pure un Galeno, un <lb/>Vesalio. </s>

<s>E conforme a una tal professione di fede, il Colombo os&shy;<lb/>serva i fatti, e come gli si rappresentano agli occhi, fedelmente <lb/>cos&igrave; gli descrive, facendo tratto tratto le maraviglie che quello stesso <lb/>gran Vesalio, il quale non la finisce mai contro Galeno, per aver <lb/>descritta l'anatomia non dell'uomo, ma delle scimmie, egli, il cen&shy;<lb/>sore ardente, l'obiurgatore ingiurioso sia bene spesso caduto negli <lb/>errori stessi rinfacciati a Galeno. </s>

<s>Questa specie di recriminazione <lb/>occorre al Nostro di farla a ogni pi&egrave; sospinto, ma specialmente a <lb/>proposito de'muscoli della laringa e dell'occhio. </s></p><p type="main">

<s><emph type="italics"/>De oculis<emph.end type="italics"/> &egrave; il soggetto proprio del X libro, intorno a che &egrave; <pb xlink:href="020/01/106.jpg" pagenum="87"/>per prima cosa sollecito di avvertire il lettore che, innanzi a lui, <lb/>nessun altro anatomico non aveva descritto veramente, se non l'oc&shy;<lb/>chio del bruto. </s>

<s>Ond'&egrave; che egli esce con ardente zelo a rimprove&shy;<lb/>rare e a muovere accuse contro gli uomini della scienza, e special&shy;<lb/>mente contro Galeno e il Vesalio, <emph type="italics"/>qui tantam rem, tam illustrem, <lb/>tam optatam, tam negligenter scribendam putarent, belluinum <lb/>oculum pro humano dissecantes<emph.end type="italics"/> (ibi, pag. </s>

<s>216). </s></p><p type="main">

<s>Quando per&ograve; il Colombo, invitato dalla nobilt&agrave; e dalla impor&shy;<lb/>tanza del soggetto, entra a far l'anatomia dei mezzi refringenti e <lb/>a speculare intorno a'loro ottici effetti, par che non sappia ripeter <lb/>altro di meglio delle dottrine ricevute per tradizione da'suoi mag&shy;<lb/>giori. </s>

<s>Il principale strumento del vedere, &egrave;, secondo lui, come per <lb/>Galeno e per il Vesalio, l'umor cristallino, il qual cristallino perci&ograve; <lb/><emph type="italics"/>idolum simulacrumque visionis non iniure appellatur<emph.end type="italics"/> (ibi, pag. </s>

<s>219). <lb/>Nonostante si dee al Nostro una curiosa esperienza in proposito, <lb/>che egli ivi accenna, ed &egrave; quella dell'avere estratto il cristallino <lb/>dall'occhio, e dell'aver trovato che i caratteri di uno scritto appa&shy;<lb/>riscono ingranditi a chi traguarda con esso, e questa dice esser <lb/>forse l'occasione che port&ograve; a far la prima scoperta degli occhiali. <lb/>&ldquo; Huius substantia durinscula est, quam sia sua sede dimoveris, et <lb/>ad scriptos caracteres accedat, maiores esse videntur et facilius <lb/>conspiciuntur, suspicorque hinc specillorum inventionem origi&shy;<lb/>nem duxisse &rdquo; (ibi). </s></p><p type="main">

<s>Fin qui il grande anatomico cremonese non ha fatto altro che <lb/>insistere sulle orme del Vesalio, il quale, nel descriver la fabbrica <lb/>del corpo umano si trattenne principalmente intorno alle parti este&shy;<lb/>riori composte delle ossa, dei muscoli e dei ligamenti. </s>

<s>La Splacno&shy;<lb/>logia, la parte pi&ugrave; importante e pi&ugrave; nuova, dal Brussellese fu ap&shy;<lb/>pena sfiorata. </s>

<s>Ma Realdo ha nell'Opera sua due libri insigni, il <lb/>VII che &egrave; <emph type="italics"/>De corde et arteriis,<emph.end type="italics"/> e l'XI che &egrave; <emph type="italics"/>De visceribus,<emph.end type="italics"/> e se&shy;<lb/>gnatamente <emph type="italics"/>De pulmone.<emph.end type="italics"/></s></p><p type="main">

<s>In generale dagli storici dell'anatomia non si d&agrave; altro merito <lb/>al Nostro, che di aver detto il mediastino del cuore non essere <lb/>perforato. &ldquo; Inter hos ventriculos septum adest, per quod fere omnes <lb/>existimant sanguini a dextro ventriculo ad sinistrum aditum pa&shy;<lb/>tefieri.... sed longa errant via, nam sanguis per arteriosam venam <lb/>ad pulmonem fertur, ibique attenuatur, deinde cum aere una per <lb/>arteriam venalem ad sinistrum cordis ventriculum defertur. </s>

<s>Quod <lb/>nemo hactenus aut animadvertit aut scriptum reliquit, licet maxime <lb/>sit ab omnibus animadvertendum &rdquo; (ibi, pag. </s>

<s>177). La piccola cir-<pb xlink:href="020/01/107.jpg" pagenum="88"/>colazione pulmonare si persuadono gli storici che fosse stata de&shy;<lb/>scritta gi&agrave; da Galeno, e che fosse il Cesalpino precursore non solo, <lb/>ma competitor coll'Harvey. </s>

<s>In quel capitolo dove da noi, dietro un <lb/>diligente esame dei documenti, si narra la storia della scoperta del <lb/>circolo sanguigno, troveranno dimostrato i lettori come le teorie <lb/>galeniche non consistessero in altro che in un giochetto di parole, <lb/>e vedranno come il Cesalpino sciogliesse quel giochetto, riducendo <lb/>al loro vero valore anatomico l'espressioni che ricorrono nell'autor <lb/>greco di <emph type="italics"/>vena arteriosa<emph.end type="italics"/> e di <emph type="italics"/>arteria venosa.<emph.end type="italics"/></s></p><p type="main">

<s>Ma quel giochetto era stato sciolto prima da Realdo Colombo, <lb/>il quale, dimostrando che tra il cuore e il polmone intercede un <lb/>circolo continuo di sangue, disse che i dutti erano una vera arteria <lb/>e una vera vena, nonostante che quella movesse dal ventricolo de&shy;<lb/>stro e questa dal ventricolo sinistro del cuore. </s></p><p type="main">

<s>Scrivono gli Anatomici, cos&igrave; con memorande parole si esprime <lb/>il Colombo, che ufficio proprio dell'arteria venosa sia quello di por&shy;<lb/>tar l'aria alterata nel cuore, ai polmoni, i quali, a guisa di flabelli <lb/>stanno l&igrave; ordinati a fargli vento e a rinfrescarlo dai soverchi ardori. </s>

<s><lb/>Quegli stessi poco prudenti, prosegue a dire, si persuadono che nel <lb/>cuore si generino fumi, quasi fosse un focolare sopra a cui siano <lb/>state gittate ad ardere legna verdi. &ldquo; Ego vero oppositum prorsus <lb/>sentio hanc scilicet arteriam venalem factam esse ut sanguinem <lb/>cum aere e pulmonibus mixtum adferant ad sinistrum cordis <lb/>ventriculum &rdquo; (ibi, pag. </s>

<s>178). </s></p><p type="main">

<s>Ecco la grande rivelazione fatta alla scienza, ecco una grande <lb/>scoperta: l'arteria venosa non ha nulla delle propriet&agrave; naturali delle <lb/>vene, ma &egrave; una vera arteria, perch&egrave;, anch'essa, come la grande <lb/>arteria riversa il sangue nel ventricolo sinistro del cuore. </s>

<s>E che ci&ograve; <lb/>sia vero, verissimo, che cio&egrave; per quel dutto arterioso, che dal pol&shy;<lb/>mone viene al cuore scorra sangue e non aria fuligginosa, com'era <lb/>fin allora generalmente creduto, il nostro Autore lo prova invocando <lb/>l'esperienza, non solo sui cadaveri, ma sopra gli stessi animali vivi, <lb/>nei quali <emph type="italics"/>hanc arteriam in omnibus sanguine refertam invenies, <lb/>quod nullo pacto eveniret si ob aerem dumtaxat, et vapores con&shy;<lb/>structa foret. </s>

<s>Quocirca ego illos anatomicos non possum satis mi&shy;<lb/>rari qui rem tam praeclaram, tantique momenti non animadverte&shy;<lb/>rint<emph.end type="italics"/> (ibi). </s></p><p type="main">

<s>E questo, si pu&ograve; dire, il primo elettissimo frutto dell'esperienza <lb/>applicata alla Fisiologia, la quale esperienza com'ha condotto Realdo <lb/>a scoprire il fatto della circolazion polmonare, cos&igrave; lo conduce alla <pb xlink:href="020/01/108.jpg" pagenum="89"/>scoperta di quell'altro importantissimo fatto a lui relativo, a quello <lb/>della respirazione. </s>

<s>I polmoni non son flabelli, come scioccamente <lb/>credevano gli antichi, ma loro ufficio proprio &egrave; quello di rimescolar <lb/>l'aria col sangue rendendolo pi&ugrave; tenue e pi&ugrave; spiritoso. </s>

<s>Questo san&shy;<lb/>gue &egrave; per l'arteria venosa ricondotto al cuore e di l&igrave;, per la grande <lb/>arteria, a tutto quanto il corpo (ivi, pag. </s>

<s>223). A questo punto per&ograve; <lb/>il nostro Autore sente come la novit&agrave; del fatto, che nessuno ancora <lb/>ha sognato, sar&agrave; per commuovere gli animi degl'increduli e pi&ugrave; <lb/>vivamente quello degli aristotelici, i quali s'aspetta che lo repute&shy;<lb/>ranno un paradosso. </s>

<s>Ma egli vuol che gli sia fatta ragione, non <lb/>dall'autorit&agrave; dei maestri, ma da quella della esperienza, per cui <lb/>cos&igrave; caldamente conclude rivolgendo tali eloquenti parole al suo <lb/>lettore: &ldquo; Tu vero, candide lector, doctorum hominum studiose, ve&shy;<lb/>ritatis autem studiosissime, experire, obsecro, in brutis animanti&shy;<lb/>bus, quae viva ut seces moneo atque hortor: experire inquam an <lb/>id quod dixi cum re ipsa consentiat, nam in illis arteriam venalem <lb/>illiusmodi sanguinis plenam invenies non aere plenam aut fumis, <lb/>ut vocant, capinosis &rdquo; (ibi, pag. </s>

<s>224). </s></p><p type="main">

<s>Che se mirabile &egrave; un tal sicuro uso dell'esperienza, in un <lb/>autore della prima met&agrave; del secolo XVI, non men mirabile &egrave; l'uso <lb/>ch'egli sa fare dell'induzione. </s>

<s>La verit&agrave; del circolo sanguigno egli <lb/>sagacemente la induce dall'artifizio e dai manifesti ufficii, a cui <lb/>sono ordinate le valvole del cuore, le quali son, per maggior sicu&shy;<lb/>rezza, fermate e mantenute in posto da certi filamenti, che, presi <lb/>da Aristotile per nervi, lo fecero andare in quella perniciosa sen&shy;<lb/>tenza che i nervi stessi avessero origine dal cuore e non dal cer&shy;<lb/>vello e dalla midolla spinale (ivi, pag. </s>

<s>179). Altro bell'esempio di <lb/>un argomento d'induzione ci si porge da quel ragionamento ch'ei <lb/>fa, per dimostrar che il sangue vitale, il sangue arterioso, non pu&ograve; <lb/>in altro organo generarsi che nel polmone. </s>

<s>Quel ragionamento, a <lb/>cui chiede poi cos&igrave; caldamente il conforto dell'esperienza, &egrave; rivolto <lb/>a persuadere gl'increduli aristotelici <emph type="italics"/>quos oro rogoque ut pulmo&shy;<lb/>nis magnitudinem contemplentur, quae absque vitali sanyuine per&shy;<lb/>manere non poterat, cum nulla sit tam minima corporis particula, <lb/>quae illo destituatur. </s>

<s>Quod si vitalis hic sanguis in pulmonibus <lb/>non gignitur, a qua parte trasmitti poterat, praeter quam ab ahorti <lb/>arteria? </s>

<s>et ab ahorti arteria ramus nullus neque magnus neque <lb/>parvulus ad pulmones mittitur<emph.end type="italics"/> &rdquo; (ibi, pag. </s>

<s>223). </s></p><p type="main">

<s>Tali erano gl'inizii, che Realdo Colombo, non finito mai d'am&shy;<lb/>mirare dai giusti estimatori, dava in Italia alla scienza sperimentale <pb xlink:href="020/01/109.jpg" pagenum="90"/>applicata alla fabbrica anatomica del corpo umano e alle funzioni <lb/>fisiologiche di lui. </s>

<s>Egli ebbe una illustre sequela ne'nomi di Bar&shy;<lb/>tolommeo Eustachio, di Gabriele Falloppio, di Girolamo Fabrizi <lb/>d'Acquapendente, a'quali ripensando la scienza italiana si sopra&shy;<lb/>esalta. </s>

<s>Or chi non crederebbe mai che succedendo cos&igrave; fatti uomini <lb/>al Cremonese, per non interrotta catena infino alla fine del se&shy;<lb/>colo XVI, non dovessero portare infino a'suoi pi&ugrave; alti fastigi l'ana&shy;<lb/>tomia sperimentale? </s>

<s>Chi non s'aspetterebbe che la luminosa dimo&shy;<lb/>strazione data da Realdo della piccola circolazione polmonare non <lb/>dovesse alle mani di tre tali insigni anatomici suoi successori com&shy;<lb/>piersi nella scoperta del circolo universale del sangue ne'suoi vasi? </s></p><p type="main">

<s>Eppure &egrave; un fatto, che desta gran maraviglia in chi vi ripensa, <lb/>&egrave; un fatto, dico, che cos&igrave; l'Eustachio come il Falloppio e l'Acqua&shy;<lb/>pendente non fecero altro pi&ugrave; che ripetere le viete dottrine di <lb/>Galeno e del Vesalio intorno alle funzioni fisiologiche del cuore e <lb/>del polmone. </s>

<s>Il libro <emph type="italics"/>De re anatomica<emph.end type="italics"/> fu per loro come se fosse <lb/>stato scritto al vento. </s>

<s>Solamente il Vidio e l'Aranzio, un po'pi&ugrave; <lb/>tardi dell'Eustachio e del Falloppio, si rivolsero a confermare a il&shy;<lb/>lustrare e a difendere il sistema cardiaco del grande Maestro cre&shy;<lb/>monese, ma non osando negare al fegato le funzioni di secernere <lb/>il sangue venoso alimentatore, n&egrave; sapendo a quale altro pi&ugrave; cospi&shy;<lb/>cuo ufficio potesse essere ordinato quel viscere dalla Natura, s'ar&shy;<lb/>restarono a quel punto dov'era, speculando e sperimentando, per&shy;<lb/>venuto il Colombo. </s>

<s>Il Cesalpino pose con nuovi argomenti in piena <lb/>evidenza la circolazion polmonare, e non badando troppo al fegato, <lb/>rivolse principalmente la sua attenzione sulle funzioni del cuore. </s>

<s><lb/>Ma il troppo servile ossequio di lui ai placiti aristotelici gl'imped&igrave; <lb/>di precorrere con libero piede alla gloriosa scoperta arveiana. </s></p><p type="main">

<s>Cos&igrave;, maestro in cattedra rimase unico Andrea Vesalio, da cui <lb/>s'impar&ograve; a coltivare l'Anatomia descrittiva, infaustamente lasciando <lb/>negletta quell'anatomia sperimentale instituita dal successore di lui, <lb/>a cui pi&ugrave; meritamente forse s'apparterrebbe il titolo di divino. </s>

<s><lb/>Seguendo per&ograve; i discepoli gli ammaestramenti dell'odiato e perse&shy;<lb/>guitato Brussellese, non ne imitarono gli esempi, quanto al modo <lb/>di porgerli o con la viva voce o con gli scritti. </s>

<s>Che se non ci s'in&shy;<lb/>travedesse sotto sotto uno splendor vivo di luce, apertamente poi <lb/>sfolgorata nelle dottrine darviniane de'nostri giorni, si chiamerebbe <lb/>un sottile artifizio di furberia quello, col quale il Falloppio intende <lb/>a conciliar, nelle anatomiche dissezioni fetali, Galeno e il Vesalio. </s>

<s><lb/>Ma n&egrave; furberia n&egrave; arte scaltrita si direbbe quella, colla quale <pb xlink:href="020/01/110.jpg" pagenum="91"/>l'Acquapendente &egrave; geloso di non offendere la reputazion di Galeno, <lb/>e di non mostrarsi apertamente mai ribelle alle dottrine aristote&shy;<lb/>liche. </s>

<s>Quella &egrave; religiosa fede non finta, sebbene il medico milio&shy;<lb/>nario, il latinista eloquente senta alitarsi in petto le aure della <lb/>nascente libert&agrave;, invocando talvolta, contro Aristotile stesso e contro <lb/>Galeno, la sua propria esperienza. </s></p><p type="main">

<s>Forse le splendide illustrazioni splacnologiche del Colombo si <lb/>neglessero dai successori di lui, e si neglessero insieme gl'iniziati <lb/>metodi sperimentali, per secondar ci&ograve; che altamente si reclamava <lb/>dai tempi; tempi in cui risvegliato l'uomo dai sonni contemplativi <lb/>di Platone e sollevatosi dai fanciulleschi trastulli aristotelici, si sen&shy;<lb/>tiva trasportato a impossessarsi del mondo, mettendo in esercizio <lb/>e invocando aiuti agli organi de'sensi, tra'quali &egrave; tenuto il primo <lb/>luogo dalla vista e dall'udito. </s>

<s>S'intende perci&ograve; come dovessero esser <lb/>questi i primi ad essere anatomicamente investigati. </s>

<s>E infatti l'Eu&shy;<lb/>stachio scopre e descrive quella tuba aerea, alla quale &egrave; rimasto <lb/>tuttavia il nome del discopritore, e che mette in comunicazione le <lb/>cavit&agrave; interne dell'orecchio con quelle della bocca. </s>

<s>Il Falloppio ci d&agrave; <lb/>quella mirabile descrizione di tutte le pi&ugrave; minute parti della rocca <lb/>petrosa, e l'Acquapendente scrive un Trattato intero sugli organi e <lb/>sulle funzioni della voce, della vista e dell'udito, che diletta col bello <lb/>stile ed erudisce colla dottrina. </s></p><p type="main">

<s><emph type="center"/>XII.<emph.end type="center"/></s></p><p type="main">

<s>Cos&igrave; con Bartolommeo Eustachio, morto nel 1574, con Gabriele <lb/>Falloppio morto in giovane et&agrave; di 40 anni nel 1563, e con Giro&shy;<lb/>lamo Fabrizi che dal 1537 protrasse la lunga e onorata vecchiezza <lb/>infino al 1619, si varcava di alquanti passi la soglia che s'interpone <lb/>fra l'uscir del secolo XVI e l'entrar del seguente secolo alle scienze <lb/>sperimentali tanto altamente glorioso. </s>

<s>Pervenuti a questo punto giova <lb/>ritornare indietro e raccogliere in un pensiero le cose fin qui lun&shy;<lb/>gamente discorse. </s>

<s>La filosofia accademica, per s&egrave; contemplativa e <lb/>sterile di scoperte sperimentali, veniva fecondata dai cultori del&shy;<lb/>l'arte, i quali mostraron di fatto non esser vero che sempre i sensi <lb/>sono a noi occasione inevitabile d'inganni. </s>

<s>La filosofia peripatetica <lb/>anch'essa veniva emendata dal Razionalismo, uscito a dimostrar che <pb xlink:href="020/01/111.jpg" pagenum="92"/>il diritto riserbato al solo Aristotile era proprio del libero ingegno <lb/>di ogni uomo. </s>

<s>Dall'altra parte Realdo Colombo aveva dato i pi&ugrave; <lb/>savii esempii di quella filosofica libert&agrave;, e ne avea raccolti squisi&shy;<lb/>tissimi frutti. </s>

<s>Infin dalla seconda met&agrave; del secolo XVI, s'eran dun&shy;<lb/>que fatti nella via del metodo sperimentale notabili progressi, a <lb/>rendere i quali pi&ugrave; spediti mancavano ancora due cose: che dai <lb/>cultori dell'arte passassero gli esercizii sperimentali ne'libri dei <lb/>filosofi, e che il soggetto anatomico in che erasi ristretto il Colombo <lb/>si estendesse a ogni sorta di fatti naturali. </s>

<s>Ad adempire a un tale <lb/>ufficio furono deputati, nell'ordine della Storia, due napoletani, <lb/>Giovan Battista Porta e Ferrante Imperato, o come altri vuole Co&shy;<lb/>lantonio Stalliola, su'due quali conviene a noi ora intrattenere al&shy;<lb/>quanto il nostro Discorso. </s></p><p type="main">

<s>Il Porta, che mor&igrave; nel 1615, si trov&ograve; spettatore e parte alla <lb/>inaugurazione de'trionfi di Galileo, e vide sboccare i rivi della sua <lb/>scienza a rimescolarsi con le larghe onde sonanti di questo fiume <lb/>reale. </s>

<s>A molti que'rivi parvero scarsi, alcuni altri di pi&ugrave; gli repu&shy;<lb/>tarono impuri e limacciosi. </s>

<s>Martino Hasdale si sforza di convincere <lb/>con infinite tare il nostro Napoletano, dicendo ch'ei <emph type="italics"/>non intendeva <lb/>molti capitoli della Mag&igrave;a, n&egrave; manco la sapeva spiegare in vol&shy;<lb/>gare, iscusandosi che erano tutte cose avute da altri cos&igrave; scritte <lb/>in latino, come stavano stampate nel suo libro<emph.end type="italics"/> (Alb. </s>

<s>VIII, 84). Il <lb/>Sagredo giudica il libro della Mag&igrave;a Naturale <emph type="italics"/>goffissimo al possibile,<emph.end type="italics"/><lb/>e stima che l'Autore fra'dotti <emph type="italics"/>tenga il luogo che tengono le cam&shy;<lb/>pane tra gli strumenti di musica<emph.end type="italics"/> (Alb. </s>

<s>Suppl., pag. </s>

<s>67, 68). Que&shy;<lb/>sti giudizi erano pronunziati al cospetto di Galileo, che tacendo, <lb/>compiacente acconsentiva. </s>

<s>Il Kepler per&ograve; ne giudicava pi&ugrave; retta&shy;<lb/>mente, e con animo imparziale. </s>

<s>Ringraziava da un lato il Porta che <lb/>gli avesse insegnato il modo come si fa la vista, e dall'altro non <lb/>taceva che certe conclusioni ottiche di lui erano <emph type="italics"/>ex insufficienti et <lb/>non universali demonstratione profectae<emph.end type="italics"/> (Paralip. </s>

<s>ad Vitell., Fran&shy;<lb/>cof. </s>

<s>1604, pag. </s>

<s>180). </s></p><p type="main">

<s>Con questo giudizio del Kepler per&ograve; si concilia il giudizio dello <lb/>stesso Sagredo, uomo da non perdere il senno per compiacere al <lb/>suo Galileo. </s>

<s>Egli infatti veniva a dire che nel libro della Mag&igrave;a vi <lb/>erano delle gofferie, ma ci aveva pur trovata anco quella gran ve&shy;<lb/>rit&agrave; della teorica della visione. </s>

<s>Dall'altra parte l'esempio delle cam&shy;<lb/>pane, alle quali si fa dir quel che uno vuole, era benissimo applicato <lb/>a qualificar quegli enimmi, di cui il Porta tanto si compiace. </s>

<s>Il <lb/>sentenziar poi che il Napoletano seguiva lo stile dei filosofi piut-<pb xlink:href="020/01/112.jpg" pagenum="93"/>tosto che quello dei matematici (Alb. </s>

<s>Suppl., pag. </s>

<s>60) includeva un <lb/>giudizio acutissimo e vero. </s>

<s>Per filosofi infatti intendeva il Sagredo <lb/>i settatori di Aristotile, e per matematici, i seguaci del retto me&shy;<lb/>todo sperimentale. </s>

<s>Ora &egrave; verissimo che, per la massima parte, nel <lb/>libro del Porta la Natura scaturisce al modo aristotelico, per quasi <lb/>magica incantazione dalla fantasia dell'Autore. </s>

<s>Verissime altres&igrave; pos&shy;<lb/>sono essere le tare appostegli dall'Hasdale, e anche molte se si <lb/>vuole, non per&ograve;, com'egli dice, infinite. </s>

<s>Si ripensi poi che cos&igrave; fatte <lb/>tare erano inevitabili a chi si era proposto di allettare col maravi&shy;<lb/>glioso, e si era dato a raccoglier per ogni parte la scienza naturale <lb/>dispersa, in un libro solo. </s>

<s>Nella prefazione alla Mag&igrave;a Naturale in <lb/>XX libri, l'Autore dice chiaramente di avere a compor l'opera sua <lb/>sfiorate le carte di tutti, che ne avevano scritto prima di lui. &ldquo; Dein, <lb/>quum Italiani, Galliam et Hispaniam peragrassem, bibliothecas et <lb/>doctissimos quosque adii, artifices etiam conveni, ut si quid novi <lb/>curiosique nacti essent ediscerem. </s>

<s>&rdquo; Poco di poi soggiunge che <lb/>prima di consegnare al suo libro le raccolte notizie, <emph type="italics"/>intensissimo <lb/>studio pertinacique experientia<emph.end type="italics"/> erasi dato a sceverar le vere dalle <lb/>false, ma pur troppo sar&agrave; talora mancato al suo proposito come <lb/>disse l'Hasdale, e tal altra non vi sar&agrave; riuscito. </s></p><p type="main">

<s>L'Opera della Mag&igrave;a Naturale per&ograve;, che &egrave; quella sola su cui <lb/>par che l'Hasdale e il Sagredo e il Kepler giudicassero dei meriti <lb/>scientifici del Porta, non vuole esser passata da noi senza qualche <lb/>breve, ma pur diligente esame. </s>

<s>Comparve prima in quattro libri <lb/>pubblicata dall'Autore, quando aveva quindici anni, poi in libri XX <lb/>quando, come dice l'Autore stesso nella Prefazione, ne aveva cin&shy;<lb/>quanta. </s>

<s>Essendo egli nato nel 4535, come s'ha dal Catalogo de'Lin&shy;<lb/>cei, sotto la prima forma il libro dee esser dunque stato pubblicato <lb/>nel 1550; sotto la seconda, nel 1585. Nonostante, della Mag&igrave;a in <lb/>IV libri, dicono i Bibliografi, la prima edizione che si conosca esser <lb/>quella fatta da Mattia Cancer in Napoli, nel 1558, otto anni dunque <lb/>posteriore a quella, che veramente, secondo attesta lo stesso Autore, <lb/>&egrave; la prima. </s>

<s>Qui, di ci&ograve; che pi&ugrave; importa alla storia della Scienza, <lb/>non s'ha che l'ultimo libro, nel secondo capitolo del quale si legge <lb/>la descrizione della camera oscura, con l'applicazione di lei alla <lb/>teoria della vista. </s>

<s>Nel cap. </s>

<s>XVIII, dove insegna in che modo s'im&shy;<lb/>piombino i vetri per uso di specchi, &egrave; notabile quel che dice del <lb/>fondo dell'occhio rassomigliato nella forma e nell'ufficio a uno spec&shy;<lb/>chio concavo, in cui fa da amalgama il pimmento coroideo. </s></p><p type="main">

<s>La prima edizione della Mag&igrave;a Naturale in XX libri, se quel-<pb xlink:href="020/01/113.jpg" pagenum="94"/>l'anno della nascita &egrave; vero, e se &egrave; vero ci&ograve; che dice l'Autore, do&shy;<lb/>vendo esser del 1585, forse &egrave; quella in 16.&deg;, che nelle recensioni <lb/>bibliografiche ha la data &ldquo; Antuerpiae ex officina Christofori Plan&shy;<lb/>tini M.D.LXXXV. &rdquo; Procediamo cos&igrave; dubitativi, vedendo notate altre <lb/>tre edizioni anteriori all'LXXXV, una del LXIX, e le altre due <lb/>del LXXVI e dell'LXXXI: ch&egrave;, se, non &egrave; abbaglio preso da'biblio&shy;<lb/>grafi non sapremmo per verit&agrave; conciliare il fatto coi detti dell'Autore. </s></p><p type="main">

<s>In qualunque modo, abbiamo in questa nuova Mag&igrave;a moltipli&shy;<lb/>cate le curiosit&agrave;, e diciamolo francamente col Sagredo, le gofferie, <lb/>ma abbiamo anco insieme moltiplicati i contributi alla scienza. </s>

<s>Ch&egrave; <lb/>l&agrave; dove questi contributi si riducevano a un libro solo, qui si di&shy;<lb/>stendono in quattro: nel VII <emph type="italics"/>De miraculis magnetis<emph.end type="italics"/> nel XVII <emph type="italics"/>De <lb/>catoptricis imaginibus,<emph.end type="italics"/> nel XVIII <emph type="italics"/>De staticis experimentis,<emph.end type="italics"/> nel XIX <lb/><emph type="italics"/>De pneumaticis.<emph.end type="italics"/></s></p><p type="main">

<s>Nel VII son raccolte l'esperienze sul magnete fatte da Paolo <lb/>Sarpi, che l'Autore nella prefazioncella al libro, chiama splendor di <lb/>Venezia, anzi d'Italia. </s>

<s>Il magnetizzamento delle verghe di ferro per <lb/>confricazione e per influenza, con molti altri fatti nuovamente os&shy;<lb/>servati e diligentemente descritti, attestano che la scienza magne&shy;<lb/>tica ebbe in Italia gl'inizii quindici anni per lo meno prima che in <lb/>Inghilterra. </s>

<s>Nel XVII libro la camera oscura nella sua descrizione <lb/>vien perfezionata coll'aggiunta della lente cristallina biconvessa, che <lb/>si applica al foro per cui s'intromettono i raggi, e ci&ograve; conduce <lb/>l'Autore, a modificar la prima teorica della visione, sostituendo le <lb/>refringenze del cristallino alle riflessioni speculari della coroide <lb/>(Cap. </s>

<s>VI). </s></p><p type="main">

<s>Il Capitolo VIII del XVIII libro &egrave; notabile per la descrizione <lb/>della bilancetta idrostatica a risolvere praticamente il <emph type="italics"/>Problema della <lb/>Corona,<emph.end type="italics"/> e a ritrovare il peso specifico de'varii corpi duri. </s>

<s>Anco <lb/>quando fosse vero quel che dice il Viviani, che cio&egrave; Galileo avesse in&shy;<lb/>ventato quello strumento nel 1586, tempo in cui incominci&ograve; ad atten&shy;<lb/>dere agli studii intorno alle opere di Archimede, il Porta lo avrebbe <lb/>preceduto di un anno per lo meno, e di 18 anni avrebbe preceduto <lb/>il Ghetaldo. </s>

<s>Comunque siasi, il Porta nel Cap. </s>

<s>VI di questo stesso <lb/>libro dette in que'galleggianti volgari, meglio che nella bilancetta, <lb/>i veri e legittimi progenitori di quegli idrostammi o densimetri o <lb/>pesa liquori inventati gi&agrave; e messi in uso in que'Medicei consessi, <lb/>che precedettero all'Accademia del Cimento. </s>

<s>La Pneumatica per&ograve; <lb/>del libro XIX non ha nulla, a voler dire il vero, che la renda no&shy;<lb/>tabile sopra quella dell'antico Herone. </s></p><pb xlink:href="020/01/114.jpg" pagenum="95"/><p type="main">

<s>N&egrave; si creda poi che negli altri libri della Mag&igrave;a tutto sia goffag&shy;<lb/>gine e stravaganze. </s>

<s>Quando, nella citata prefazioncella al VII libro, <lb/>l'Autore indovinava che due uomini si potessero parlar di lontano <lb/><emph type="italics"/>duobus nauticis pyxidibus alphabeto circumscriptis,<emph.end type="italics"/> parve certa&shy;<lb/>mente a Galileo che avesse detto una stravaganza, e nel I Dialogo <lb/>dei Massimi Sistemi (Alb. </s>

<s>I, 107) se ne ride e inventa su quel fatto <lb/>argutamente una burla. </s>

<s>Qual sarebbe rimasto se si fosse trovato a <lb/>veder nel telegrafo a galvanometro perfettamente avverata la tanto <lb/>stravagante profezia! </s></p><p type="main">

<s>Tutte le goffaggini poi e le stravaganze son dall'Autore assom&shy;<lb/>mate nell'ultimo libro, che meritamente &egrave; intitolato <emph type="italics"/>Chaos.<emph.end type="italics"/> Eppure <lb/>anche qui, come pietre preziose rotolate fra'ciottoli di un fiume, <lb/>s'ha nel Cap. </s>

<s>V la descrizione del corno acustico, strumento che <lb/>serve a inacutir l'udito, come a inacutir la vista servono, egli dice, <lb/>acconciamente disposte, due lenti. </s>

<s>Notabile quel ch'egli scrive es&shy;<lb/>sergli stata una tale invenzione suggerita dalle orecchie degli ani&shy;<lb/>mali, e particolarmente delle lepri, e pi&ugrave; notabile il principio ge&shy;<lb/>nerale che ivi professa del doversi perscrutar la natura, e imitar <lb/>con l'arte i macchinamenti di lei. </s></p><p type="main">

<s>Ci&ograve; che s'&egrave; fin qui discorso, pu&ograve; servire a giustificare il Porta <lb/>dalle imputazioni dell'Hasdale e del Sagredo, ma non si vuol tacere <lb/>come que'severi giudizi non furon dati che sul libro della Mag&igrave;a, <lb/>quasi non avesse l'Autore pubblicati altri documenti della sua scienza. </s>

<s><lb/>Eppure, quando l'Hasdale e il Sagredo scrissero i due sopra citati <lb/>giudizii in due lettere scritte a Galileo, aveva il Porta pubblicati, <lb/>fra gli altri, due libri, de'quali sarebbe colpa tacere nella storia <lb/>de'progressi fatti, in sul finir del secolo XVI dalla scienza speri&shy;<lb/>mentale italiana. </s>

<s>Di que'due libri il primo &egrave; <emph type="italics"/>De refractione optices<emph.end type="italics"/><lb/>pubblicato in Napoli nel 1593, il secondo &egrave; <emph type="italics"/>Pneumaticorum libri <lb/>tres<emph.end type="italics"/> che vide pure in Napoli la luce nel 1601. Il Sagredo non dee <lb/>aver veduto quel libro di Ottica, forse perch&egrave; difficile a trovarsi <lb/>venale. </s>

<s>Anche il Kepler infatti, che ardeva di gran desiderio di ve&shy;<lb/>der quel che vi avesse scritto l'Autore intorno alle rifrazioni della <lb/>luce attraverso le lenti, dice nei Paralipomeni a Vitellione &ldquo; a li&shy;<lb/>brariis frustra hactenus requisivi &rdquo; (edit. </s>

<s>cit. </s>

<s>pag. </s>

<s>202). Non dee il <lb/>Sagredo, lo ripetiamo, aver veduto quel libro, perch&egrave;, sagace e giu&shy;<lb/>dizioso qual'era, non par possibile ch'ei non si sentisse come noi <lb/>sorpreso di maraviglia e non restasse alla prima in dubbio se quello <lb/>l&igrave; era proprio l'Autore goffissimo della Mag&igrave;a. </s>

<s>Il Kepler senza dub&shy;<lb/>bio si sarebbe dalla lettura confermato in quel suo giudizio, che il <pb xlink:href="020/01/115.jpg" pagenum="96"/>fisico napoletano avesse mente davvero e cognizioni diottriche tali, <lb/>da specular l'invenzione del canocchiale. </s>

<s>Di ci&ograve; pure si persuade&shy;<lb/>ranno con facilit&agrave; i nostri lettori, dop'avere scorso anche brevemente <lb/>i IX libri delle Diottriche rifrazioni, ma prima di far ci&ograve; vediamo <lb/>in qual modo si studiasse di raccogliere le disperse membra della <lb/>scienza naturale Ferrante Imperato. </s></p><p type="main">

<s>Il libro di lui s'intitola giusto <emph type="italics"/>Historia naturale<emph.end type="italics"/> e si pubblic&ograve; <lb/>in Napoli la prima volta nel 1599. Antonio Nardi, discepolo di Ga&shy;<lb/>lileo, in quelle sue <emph type="italics"/>Scene Accademiche,<emph.end type="italics"/> delle quali, essendo rimaste <lb/>inedite, daremo in quest'altra parte del nostro Discorso, qualche <lb/>breve notizia ai nostri lettori, giudic&ograve; il Naturalista napoletano per <lb/>uno de'pi&ugrave; avveduti e giudiziosi scrittori di cose naturali che avesse <lb/>veduto mai (MSS. Gal. </s>

<s>Disc. </s>

<s>T. XX, p. </s>

<s>592). I libri e le sentenze <lb/>dei tanti autori antichi e moderni da cui raccoglie, non le cita mai <lb/>senza darne, come dice lo stesso Nardi, <emph type="italics"/>una candida e valida cen&shy;<lb/>sura.<emph.end type="italics"/> Candida sempre, valida a seconda delle cognizioni che si po&shy;<lb/>tevano avere a que'tempi. </s>

<s>Non fa perci&ograve; maraviglia se l'Imperato <lb/>annoverando le bufoniti, gli entrochi, le pietre giudaiche, le frumen&shy;<lb/>tarie fra le sostanze minerali, ammettesse la vegetazion delle pietre; <lb/>errore largamente ricompensato da quel che poi nel rimanente del <lb/>XXV libro si specula delle pietre stesse, aprendo cos&igrave; tanto dalla <lb/>lontana le vie ai progressi della moderna cristallografia. </s></p><p type="main">

<s>Soggiunge il Nardi, nel passo sopra citato, d'aver sentito vivis&shy;<lb/>simo il desiderio che l'Autore v'avesse trattato non di sola una <lb/>parte, ma di tutta la <emph type="italics"/>fisica,<emph.end type="italics"/> alla qual parola egli d&agrave; senza dubbio <lb/>il significato di Scienza della Natura. </s>

<s>Ma accettando pure quella <lb/>parola <emph type="italics"/>fisica<emph.end type="italics"/> nel significato che suole avere oggid&igrave;, sentiamo anche <lb/>noi il desiderio che egli avesse pi&ugrave; largamente trattato di quei sog&shy;<lb/>getti di Meteorologia, di Ottica, di Magnetismo, intorno ai quali <lb/>scopre e annunzia alcune di quelle recondite verit&agrave; della fisica mo&shy;<lb/>derna, cacciando gli ostinati errori peripatetici col raziocinio e con <lb/>l'esperienza. </s>

<s>Di queste verit&agrave; scoperte e insegnate non si vuol la&shy;<lb/>sciar di dare ai lettori qualche notizia, e cos&igrave;, dopo avere accennato <lb/>alle due diverse maniere tenute in compilare la scienza ereditata <lb/>dai due scrittori napoletani, trapassare a veder ci&ograve; che seppero am&shy;<lb/>bedue speculare coi loro proprii intelletti. </s></p><p type="main">

<s>Tornando perci&ograve; al Porta, poniamoci innanzi agli occhi i due <lb/>libri sopra citati e incominciamo dallo scorrer per primo quello che <lb/>&egrave; forse di minore importanza, e che, per la rarit&agrave; dell'originale, <lb/>leggiamo nella versione italiana fatta da Ivan Escrivano e pubblicata <pb xlink:href="020/01/116.jpg" pagenum="97"/>col titolo di <emph type="italics"/>Tre libri di Spiritali<emph.end type="italics"/> in Napoli nel 1606. Le materie <lb/>ivi trattate, molto meglio che il titolo, dicono che il primo impulso <lb/>&egrave; venuto da Herone, ma l&agrave; dove il Fisico alessandrino trascura i <lb/>fondamenti della scienza e descrive le sue macchine, senza avvedersi <lb/>che a provar di metterle a gioco, non rispondono bene spesso alle <lb/>intenzioni; il Porta incomincia nel libro I dallo sperimentare sulla <lb/>elasticit&agrave; dell'aria, e dal confermare i principii dell'Idrostatica. </s>

<s>Gli <lb/>effetti dell'elaterio dell'aria compressa da uno stantuffo dentro a <lb/>una canna da archibuso, son descritti nel cap. </s>

<s>VI, ma nel X nota&shy;<lb/>bilissima &egrave; quella teoria delle pressioni de'liquidi, che per comune <lb/>sentimento degli eruditi s'attribuisce allo Stevino. </s>

<s>Vedremo che <lb/>parecchi anni prima aveva il Benedetti, nelle sue <emph type="italics"/>Speculazioni,<emph.end type="italics"/> di&shy;<lb/>mostrato gi&agrave; quel principio idrostatico, ma il Porta vi procede con <lb/>passo pi&ugrave; largo e pi&ugrave; sicuro, e che &egrave; pi&ugrave;, conferma le teorie col&shy;<lb/>l'esperienze. </s>

<s>Fra queste esperienze, a provar che le pressioni ope&shy;<lb/>rano secondo l'altezza del perpendicolo, &egrave; notabile quella del liquido <lb/>contenuto dentro una gran botte, che vien sollevato dal premer <lb/>d'altro liquido infuso in un sottil cannello comunicante, come pure <lb/>&egrave; notabile quell'altra esperienza degli zampilli, che si sollevano a <lb/>uguale altezza e raggiungon precisamente il livello del liquido nella <lb/>conserva: notabili diciamo queste esperienze del disprezzato fisico <lb/>napoletano, perch&egrave; ci fanno ripensare alla fama in che vennero poi, <lb/>per quelle stesse esperienze, il Mariotte e il Torricelli. </s></p><p type="main">

<s>Il secondo libro &egrave; applicato alla descrizione delle macchine da <lb/>sollevar l'acqua, gareggiandosi con Herone a chi sa immaginarne <lb/>delle pi&ugrave; nuovamente ingegnose. </s>

<s>Ma &egrave; qui per&ograve; debito confessare <lb/>che il Nostro cade, e forse pi&ugrave; spesso che mai, ne'difetti stessi <lb/>notati da lui nel fisico antico, proponendo macchinalmenti, che o <lb/>per l'elasticit&agrave; dell'aria o per la pressione dell'acqua, non in altro <lb/>giocano che nella esaltata fantasia dell'inventore. </s>

<s>Ne sia esempio <lb/>fra gli altri quel che nel cap. </s>

<s>I del terzo libro dice del potersi tra&shy;<lb/>vasare un lago in un altro lago o nel mare, per via di un sifone <lb/>che cavalchi l'altura di un monte: strana impresa che riuscita pa&shy;<lb/>recchi anni dopo, vuota di effetto alle mani del Baliani, gli dette <lb/>occasione a specular sulla pressione ammosferica e a indovinar la <lb/>prima teoria del barometro ad acqua. </s></p><p type="main">

<s>Questo terzo libro, che incomincia con una stranezza, termina <lb/>coll'invenzione di un utilissimo strumento, di cui da quasi tutti <lb/>s'ignora l'autore, ed &egrave; la livella ad acqna, nemmeno oggid&igrave; uscita <lb/>affatto fuor d'uso, e che il Porta fu il primo a sostituire all'antico <pb xlink:href="020/01/117.jpg" pagenum="98"/>corobate vitruviano. </s>

<s>De'capitoli di mezzo, notabile &egrave; il IV, dove si <lb/>descrive l'esperienza della diffusione del vino di un bicchiere at&shy;<lb/>traverso al piccolo foro di una palla di vetro ripiena d'acqua: espe&shy;<lb/>rienza, che nel I Dialogo delle Due Nuove scienze fu amorevolmente <lb/>raccolta da Galileo e tenuta per sua (Alb. </s>

<s>XIII, 74), come pure per <lb/>sua volle rivendicar quell'altra descritta qui dal Nostro, nel cap. </s>

<s>VII, <lb/>del materazzo o caraffella, dentro al collo della quale il calore am&shy;<lb/>biente fa scender l'acqua e il freddo la fa risalire, la quale espe&shy;<lb/>rienza il Porta stesso aveva gi&agrave; 47 anni prima descritta nel cap. </s>

<s>XXII <lb/>del secondo fra i quattro libri della Mag&igrave;a. </s></p><p type="main">

<s>Pi&ugrave; commemorabili di questi tre degli Spiritali, son per l'im&shy;<lb/>portanza e la difficolt&agrave; del soggetto, i nove libri delle <emph type="italics"/>Ottiche rifra&shy;<lb/>zioni.<emph.end type="italics"/> La scienza, infino a qui, non aveva fatto grandi progressi: <lb/>si ripetevano le dottrine antiche di Tolomeo e di Euclide, non molto <lb/>per verit&agrave; promosse da Alhazen e da Vitellione. </s>

<s>Gli scritti dell'Al&shy;<lb/>berti, del Vinci, del Maurolico a'tempi del Porta, erano sconosciuti, <lb/>cosicch&egrave;, questo Trattato del Fisico napoletano &egrave; il primo da cui la <lb/>Diottrica incomincia i suoi progressi. </s></p><p type="main">

<s>A cos&igrave; fatti progressi il primo valido impulso vien dalla pro&shy;<lb/>posizione VIII del libro I, dove l'Autore dimostra esser falso quel <lb/>che insegn&ograve; Vitellione, che cio&egrave; gli angoli dell'incidenza e della <lb/>rifrazione serbino costante proporzione geometrica, variandosi l'obli&shy;<lb/>quit&agrave; con cui cade il raggio luminoso. </s>

<s>A confermar la sua dimo&shy;<lb/>strazione, contro l'autorevole e inveterato magistero dell'Ottico po&shy;<lb/>lacco, invoca lo sperimento da farsi con un vaso ripieno d'acqua. </s></p><p type="main">

<s>Contro un altro magistero non meno autorevole per que'tempi, <lb/>ed &egrave; quello del Fracastoro settatore di pi&ugrave; antiche dottrine, &egrave; pure <lb/>la proposizione XI di questo stesso libro I, nella quale si dimostra <lb/>che la refringenza alle superficie piane non ingrandisce le immagini, <lb/>ma s&igrave; le ingrandisce alle superficie curve, conforme a ci&ograve; che pure <lb/>accennava il giovane Galileo (Ediz. </s>

<s>naz., Firenze, 1890, Vol. </s>

<s>I, <lb/>pag. </s>

<s>314). E mentre che lo stesso Galileo meditava arguzie, da tor <lb/>fede a Ticone, che fu il primo, osservando gli astri, a tener conto <lb/>degli effetti prodotti sulla vista dalle rifrazioni, &egrave; notabile quel che <lb/>nelle proposizioni XVII e XIX avverte il Porta delle fallacie che, <lb/>per via de'raggi refratti nell'aria, si commettono osservando oggetti <lb/>che radono l'orizzonte o livellando collo strumento, per lunghi tratti. </s></p><p type="main">

<s>Il secondo libro, che &egrave; delle immagini e dell'andamento dei <lb/>raggi rifratti nelle sfere cristalline, ha strettissima relazione col li&shy;<lb/>bro VIII, dove si espongono le teorie diottriche delle lenti. </s>

<s>&Egrave; questa <pb xlink:href="020/01/118.jpg" pagenum="99"/>parte del Trattato che principalmente eccitava, di vederlo, i desiderii <lb/>al Keplero, e non sappiamo se ne fosse stato poi sodisfatto, quando <lb/>nel 1611 pubblic&ograve; il Trattato suo della Diottrica. </s>

<s>Facendo per&ograve; il <lb/>confronto fra'due autori, non temiam di asserire che il secondo nel <lb/>tempo riman secondo altres&igrave; nel merito, perch&egrave; il Porta introduce, <lb/>nel divisar le immagini reali e virtuali rappresentate dalle lenti, i <lb/><emph type="italics"/>cateti,<emph.end type="italics"/> ossia gli <emph type="italics"/>assi principali e secondari,<emph.end type="italics"/> senza che, nel Kepler <lb/>e negli altri autori di que'tempi, le immagini stesse rimangono in&shy;<lb/>determinate di grandezza e di luogo. </s>

<s>Di pi&ugrave;, l'Ottico alemanno nella <lb/>proposizione sua XCVI fa convergere i raggi che escon refratti dalle <lb/>lenti concave verso l'occhio, quasi che il loro foco fosse reale e non <lb/>virtuale: errore gravissimo cansato assai destramente dal nostro Na&shy;<lb/>poletano. </s></p><p type="main">

<s>L'anatomia dell'occhio professata nel III libro &egrave; conforme alla <lb/>descrizione che ne dette il Vesalio, n&egrave; fa maraviglia che sia ripe&shy;<lb/>tuto qui l'errore, sull'autorit&agrave; di Galeno oramai divenuto comune, <lb/>del far organo della rappresentazion visiva il cristallino: senza ma&shy;<lb/>raviglia per&ograve; non si pu&ograve; passar da chi legge la proposizione VI, al <lb/>vedervisi pubblicata quella osservazione del dilatamento e del re&shy;<lb/>stringimento della pupilla annunziata sette anni dopo dall'Acqua&shy;<lb/>pendente come una osservazione nuova del Sarpi o sua. </s>

<s>Galileo <lb/>ripete quasi a parole nel III Dialogo de'Massimi Sistemi (Alb. </s>

<s>I, <lb/>394) ci&ograve; che qui avea scritto il disprezzato fisico napoletano, e nelle <lb/><emph type="italics"/>Operazioni astronomiche<emph.end type="italics"/> procede Galileo stesso in un modo simile <lb/>al Porta, per determinar l'ampiezza del foro pupillare, con una tal <lb/>sola differenza, che mentre questi attribuisce il metodo ad Archi&shy;<lb/>mede, quello, e nelle citate <emph type="italics"/>Operazioni<emph.end type="italics"/> e nelle lettere al Renieri <lb/>lo d&agrave; per invenzione sua propria. </s></p><p type="main">

<s>Se il fortunato discopritore de'satelliti di Giove si fosse mai <lb/>degnato di rivolger lo sguardo sul sesto libro di questa Diottrica, <lb/>non &egrave; qui luogo a ricercare. </s>

<s>Non si vuol tacere per&ograve;, per la novit&agrave; <lb/>e l'importanza del tema, che, secondo il Borelli, i metodi usati da <lb/>Galileo per ritrovar collo strumento la media distanza de'Gioviali <lb/>dal centro del pianeta, avrebbero avuto il loro principio dai curiosi <lb/>fenomeni, che, per l'artificiosa e forzata direzione degli assi ottici <lb/>de'due occhi, si producono nel guardare gli oggetti; fenomeni mi&shy;<lb/>rabilmente osservati e descritti dal Nostro nelle varie proposizioni <lb/>di quello stesso sesto libro. </s></p><p type="main">

<s>Nel trattare all'ultimo dell'iride e de'colori il Porta non pro&shy;<lb/>muove nemmen di un passo la scienza e si rimane anzi indietro al <pb xlink:href="020/01/119.jpg" pagenum="100"/>Maurolico per lungo tratto di via. </s>

<s>Ma Ferrante Imperato, all'<emph type="italics"/>Historia <lb/>naturale<emph.end type="italics"/> del quale ora si torna, largamente ristora il difetto del <lb/>suo concittadino, divisando dell'iride interna e della esterna la vera <lb/>teoria ottica 38 anni prima che a menarne vanto uscisse fuori il <lb/>Cartesio. </s></p><p type="main">

<s>Ma perch&egrave; il rispondere ai vanti con altrettanti vanti esaltati <lb/>&egrave; triste vezzo, che ha tolto fede oramai alle osservazioni de'pi&ugrave; <lb/>giudiziosi, vadasi all'XI libro di questa Storia, e si leggano atten&shy;<lb/>tamente i capitoli VIII e IX, osservando che l'Autore, quanto alla <lb/>vista, professa l'opinion platonica della emissione. </s>

<s>Conforme a queste <lb/>professate dottrine egli dice perci&ograve;: <emph type="italics"/>li raggi visivi infratti dagli <lb/>corpuscoli delle gocce andar dalla vista al lummare<emph.end type="italics"/> (Venetia 1672, <lb/>pag. </s>

<s>288). Come poi nelle gocciole si facciano queste infrazioni e <lb/>dalle infrazioni congiunte a riflessioni si produca l'iride colorata, <lb/>a quel modo che si vede <emph type="italics"/>negli globi et ampolle chiarissime di vetro <lb/>e nelle colonne (prismi) triangolari<emph.end type="italics"/> (ivi, pag. </s>

<s>294); lo aveva detto <lb/>con mirabile esattezza pi&ugrave; sopra, ove scrisse: &ldquo; Occorrendo la vista <lb/>alla sua superficie convessa, fa semplice riflessione e penetrando, <lb/>il che si fa con infrazione, alla cava, ivi riflessa, ritorna ad uscir <lb/>con la seconda infrazione. </s>

<s>Sono dunque due infrazioni, l'una men&shy;<lb/>tre dal pi&ugrave; raro entra nel denso, l'altra, nella quale dal pi&ugrave; denso <lb/>ritorna nel pi&ugrave; raro, quali ambe infrazioni sono nella superficie <lb/>prima che occorra, et vi &egrave; la riflessione tramezzo fatta nella super&shy;<lb/>ficie pi&ugrave; lontana &rdquo; (ivi, pag. </s>

<s>288). </s></p><p type="main">

<s>Quanto all'iride esterna che egli rimprovera ad Aristotile, <lb/>l'aver promesso, ma non mantenuto di trattarne, o trattandone di <lb/>aver ridotto il fenomeno a cause vane; ecco quel che egli dice nel <lb/>cap. </s>

<s>IX: &ldquo; Essendo della goccia due semisferi, l'uno dalla parte <lb/>dell'asse (del cono che ha l'iride per base) l'altro dalla parte op&shy;<lb/>posta, e potendo il raggio visivo nell'uno e nell'altro incorrere a <lb/>riflettersi al luminare: nel primo penetrando nell'interno ed uscendo <lb/>per l'esterno, e nel secondo penetrando per l'esterno ed uscendo <lb/>per l'interno, nel qual secondo modo il raggio che esce e va al <lb/>sole per la molta infrazione si taglia col raggio della vista che entra; <lb/>&egrave; necessario per questo che due siano gli archi celesti e che ab&shy;<lb/>biano li colori a contrario &rdquo; (ivi, pag. </s>

<s>290). Conclude notando il <lb/>licenzioso accoppiamento che Aristotile, a spiegare il fenomeno, fa <lb/>di due cause contrarie, e accennando ad altre dottrine del Filosofo <lb/>meritevoli di maggior riprensione. </s></p><p type="main">

<s>Se qui l'Imperato emenda gli errori ripetuti dal Porta nell'ul-<pb xlink:href="020/01/120.jpg" pagenum="101"/>timo libro della Diottrica, altrove intorno all'argomento del Magnete <lb/>ne compie le teorie divisate nel VII libro della <emph type="italics"/>Magia.<emph.end type="italics"/> Anche il <lb/>nostro autor dell'<emph type="italics"/>Historia naturale<emph.end type="italics"/> parlando nel libro XXVI della <lb/>pietra calamita ne avverte il magnetismo per influenza e lo illustra <lb/>con luminoso concetto, rassomigliando le linee radiose, in che si <lb/>dispongono le particelle della limatura del ferro intorno ai poli ma&shy;<lb/>gnetici, alla dirittura delle linee, in che intorno al centro della <lb/>Terra, insistendo l'uno sull'altro, si dispongono i corpi gravi (ivi, <lb/>pag. </s>

<s>614). Or che altro mancava se non che formular questo stesso <lb/>concetto a modo del Gilberto perch&egrave; riuscisse a dire che la Terra <lb/>&egrave; un magnete, e che il Magnete stesso &egrave; una terrella? </s></p><p type="main">

<s><emph type="center"/>XIII.<emph.end type="center"/></s></p><p type="main">

<s>La filosofica libert&agrave;, con la quale esamina e scopre gli errori <lb/>di Aristotile Ferrante Imperato, in quasi tutte le parti dell'opera <lb/>sua voluminosa, e specialmente dove tocca soggetti di Meteorologia, <lb/>fra'quali &egrave; notabilissimo quel che nel cap. </s>

<s>III del X libro dice del <lb/>tuono e del baleno contro il Filosofo; basterebbe a meritargli uno <lb/>dei primi seggi fra coloro che pi&ugrave; efficacemente cooperarono a re&shy;<lb/>staurare le scienze sperimentali. </s>

<s>I due libri pure del Porta da noi <lb/>sopra brevemente discorsi, son dettati col medesimo intento di sco&shy;<lb/>prir gli errori de'peripatetici non solo, ma di ogni sorta di autori <lb/>le dottrine de'quali non si conformino alla rettitudine de'raziocinii <lb/>e alla prova degli sperimenti. </s>

<s>Ma il primo de'due fisici napoletani <lb/>rimase dimenticato per ragioni che troppo lungo sarebbe l'inve&shy;<lb/>stigare, e il secondo, competitore di Galileo, rimase oscurato dai <lb/>trionfi di lui. </s>

<s>Non ebbero perci&ograve; le molte e importanti verit&agrave; sco&shy;<lb/>perte e dimostrate da'due autori quell'incontro che si sarebbero <lb/>meritato, n&egrave; recarono quegli aiuti a'progressi della scienza, che <lb/>avrebbero veramente potuto. </s></p><p type="main">

<s>Pi&ugrave; diffusa e pi&ugrave; intensa, e perci&ograve; pi&ugrave; giovevole riusc&igrave; l'opera <lb/>di tre grandi uomini nati sulle rive di quel mare, su cui regn&ograve; <lb/>libera Venezia. </s>

<s>Giovan Batista Benedetti, Santorre Santorio e Paolo <lb/>Sarpi, hanno, dopo tanto lungo tempo e tante prove tentate dai loro <lb/>predecessori, aperta alla scienza la retta via, e v'hanno impresse <lb/>oramai orme cos&igrave; profonde, che non &egrave; possibile pi&ugrave; lo smarrirle. <pb xlink:href="020/01/121.jpg" pagenum="102"/>Rimasti tutti e tre nascosti nelle fondamenta dell'edifizio galileiano, <lb/>non pu&ograve; farsi la giusta stima della loro grandezza, se non da chi <lb/>penetri addentro colla vista attenta ed acuta. </s>

<s>E a chi riguardi il <lb/>Benedetti in questo modo, se lo vede presentare innanzi in sereno <lb/>e dignitoso abito di libero filosofo, che vuol contemperare l'osse&shy;<lb/>quio all'autorit&agrave; delle tradizioni, con l'ossequio alle verit&agrave; scoperte <lb/>dalla ragione. &ldquo; Liberum enim est cuique scribere quod libet, nec <lb/>Aristotilem afficit iniuria, quicumque illi fidem suam non acco&shy;<lb/>modat, etsi valde iniquus sit quisquis maiorum opiniones veras <lb/>et ab omnibus merito comprobatas non admittit &rdquo; (Speculationum <lb/>lib. </s>

<s>Venetiis 1599, pag. </s>

<s>228). </s></p><p type="main">

<s>Nella Prefazioncella alle Disputazioni <emph type="italics"/>De quibusdam placitis <lb/>Aristotelis,<emph.end type="italics"/> dove d&agrave; il Benedetti il pi&ugrave; bell'esempio di quella filo&shy;<lb/>sofica libert&agrave; vendicatrice dei diritti della ragione, dop'avere accen&shy;<lb/>nato ai pericoli corsi da colui, che scrive cose contrarie all'am&shy;<lb/>mirabile sapienza dell'antico Maestro &ldquo; Verumtamen, egli tosto <lb/>francamente soggiunge, studio veritatis impulsus, cuius ipse amore <lb/>in seipsum si viveret excitaretur, in medium quaedam proferre <lb/>non dubitavi, in quibus me inconcussa mathematicae philosophiae <lb/>basis, cui semper insisto, ab eo dissentire coegit &rdquo; (ibi, pag. </s>

<s>168). </s></p><p type="main">

<s>Da Parma, dove insegnava, fu chiamato a Torino, dal Duca, il <lb/>quale, secondo il costume de'principi di allora, si compiaceva, spe&shy;<lb/>cialmente in tempo di villeggiatura, d'interrogare il suo Filosofo <lb/>e Matematico e di proporgli a risolvere questioni d'Aritmetica, di <lb/>Geometria, di Ottica, di Musica e anco di Astrologia. </s>

<s>Gli amici pure <lb/>lo interrogavano, e ad essi mandava i suoi <emph type="italics"/>Responsi,<emph.end type="italics"/> i quali, come <lb/>prima, egli dice &ldquo; per ocium licuit, collegi, relegi, ac tandem de <lb/>manu mittere decrevi. </s>

<s>Tum, ut scientia ipsa quo magis diffun&shy;<lb/>deretur, crescat, et quidquid valeo sine invidia, in communem <lb/>utilitatem conferam &rdquo; (ibi, pag. </s>

<s>204). </s></p><p type="main">

<s>Cos&igrave; fatti Responsi, sotto forma epistolare, son gran parte del <lb/>libro <emph type="italics"/>Speculationum<emph.end type="italics"/> stampato prima nel 1580 in Torino, e poi nuo&shy;<lb/>vamente nel 1599 in Venezia: speculazioni, che l'Autore presenta <lb/>al suo lettore per nuove, se non sempre nella sostanza, certo nel <lb/>modo di dimostrarle. </s>

<s>Ed &egrave; verissimo: &egrave; anzi per entro a quelle <lb/>pagine tanta novit&agrave;, che, scomparso affatto il vecchio mondo ari&shy;<lb/>stotelico, ti senti trasportar nell'ampie e libere regioni di un Mondo <lb/>nuovo. </s></p><p type="main">

<s>Nelle sopra citate Disputazioni contro Aristotile, quelle parole, <lb/>nelle quali chiama il nuovo Sistema del Mondo &ldquo; pulcherrimam <pb xlink:href="020/01/122.jpg" pagenum="103"/>Aristarchi Samii opinionem, divinitus a Nicolao Copernico ex&shy;<lb/>pressam, contra quam nil plane valent rationes ab Aristotile, <lb/>neque etiam a Ptolomeo propositae &rdquo; (ibi, pag. </s>

<s>195) dicono ab&shy;<lb/>bastanza chiaro quanto fosse il Benedetti inclinato a cooperare ai <lb/>progressi dell'Astronomia, ma perch&egrave; ei non fu in tempo a veder <lb/>l'invenzione del canocchiale, fu nella Meccanica e nella Fisica, dove <lb/>principalmente esercit&ograve; le sue nuove speculazioni. </s></p><p type="main">

<s>La scienza del moto, resa impossibile dagli errori di Aristotile, <lb/>era si pu&ograve; dir rimasta stazionaria ne'libri dell'antico Archimede. </s>

<s><lb/>Il nostro Benedetti fu de'pi&ugrave; validi in promuoverla, confutando con <lb/>argomenti di ragione quegli aristotelici errori, in parecchi de'quali <lb/>era incorso lo stesso Niccol&ograve; Tartaglia s&igrave; rispetto ai moti naturali <lb/>che ai violenti. </s>

<s>Cos&igrave; l'antico Filosofo di Stagira come il nuovo di <lb/>Brescia avevano insegnato che ne'gravi cadenti le velocit&agrave; son pro&shy;<lb/>porzionali alle moli, ma il nostro Veneziano gli avverte in proposito <lb/>com'e'non avevan posto mente &ldquo; quam magna resistentiarum sit <lb/>differentia, quae tam diversitate figurarum quam ex magnetudi&shy;<lb/>num varietate exoriri potest &rdquo; (ibi, pag. </s>

<s>168) e svolgendo queste <lb/>sottili speculazioni relative alle varie resistenze opposte ai mobili, <lb/>dalle varie densit&agrave; dei mezzi, conclude: &ldquo; quod in vacuo corpora <lb/>eiusdem materiae aequali velocitate moverentur &rdquo; (pag. </s>

<s>174). </s></p><p type="main">

<s>Il medesimo Aristotile aveva detto, nel cap. </s>

<s>VIII del I libro <emph type="italics"/>De <lb/>coelo,<emph.end type="italics"/> che il mobile tanto pi&ugrave; si accelera quanto pi&ugrave; si avvicina al <lb/>termine <emph type="italics"/>ad quem,<emph.end type="italics"/> ma il Benedetti avverte che avrebbe dovuto il <lb/>Filosofo dire invece che anzi il mobile si accelera tanto pi&ugrave;, quanto <lb/>pi&ugrave; si dilunga dal termine <emph type="italics"/>a quo,<emph.end type="italics"/> &ldquo; quia tanto maior fit semper <lb/>impressio quanto magis movetur naturaliter corpus, et continuo <lb/>novum impetum recipit, cum in se motus causam contineat, quae <lb/>est inclinatio ad locum suum eundi &rdquo; (ibi, pag. </s>

<s>184). </s></p><p type="main">

<s>Il Nostro insomma, un quarto di secolo prima che a queste <lb/>stesse speculazioni rivolgesse la mente Galileo, aveva pubblicamente <lb/>insegnato che ne'moti accelerati le velocit&agrave; son proporziali ai tempi, <lb/>concludendo come Galileo questo teorema fondamentale da quel <lb/>principio d'inerzia, stabilito gi&agrave; dal Cardano, e confermato colle <lb/>bellissime esperienze dello Scaligero. </s></p><p type="main">

<s>Tanto &egrave; vero che il Benedetti accoglie quel principio come cosa <lb/>gi&agrave; certa nella scienza, e dimostrata, da non vedere il bisogno di <lb/>assumersi altro ufficio, che di rimuoverne le difficolt&agrave;, come giusto <lb/>si vede far da lui nel Trattato <emph type="italics"/>De Mechanicis<emph.end type="italics"/> e nell'Epistola a Paolo <lb/>Capra <emph type="italics"/>De motu molae et trochi.<emph.end type="italics"/> Si propone ivi il quesito come mai <pb xlink:href="020/01/123.jpg" pagenum="104"/>una mola mossa non perpetua il suo moto, come dovrebbe per il <lb/>principio d'inerzia, e risponde che ci&ograve; avviene per pi&ugrave; ragioni: per <lb/>l'attrito de'perni, per la resistenza, dell'aria e per gli effetti della <lb/>forza centrifuga (ivi, pag. </s>

<s>159). E qui l'Autore, che fu primo di <lb/>tutti i meccanici a specular su questo genere di forza, stabilisce <lb/>quella legge verissima delle forze centrifughe, bench&egrave; poi stimata <lb/>falsissima da Galileo (Alb. </s>

<s>I, 233) che cio&egrave; <emph type="italics"/>quanto maior est aliqua <lb/>rota tanto maiorem quoque impetum et impressionem motus eius <lb/>circumferentiae partes necipiant<emph.end type="italics"/> (Speculat. </s>

<s>lib. </s>

<s>pag. </s>

<s>159). Ma nella <lb/>sopra citata Lettera al Capra, le speculazioni in tal proposito son <lb/>anco pi&ugrave; sottili, e, dal risolversi in orizzontale, per la vertigine, <lb/>l'impeto naturalmente diretto per la verticale, scioglie alcuni curiosi <lb/>problemi relativi allo star ritte sul punzone le trottole giranti, e al <lb/>leggerissimo gravitar sul sostegno un corpo, che vi si muova sopra <lb/>veloce (ivi, pag. </s>

<s>286). </s></p><p type="main">

<s>Rispetto ai moti violenti, il Benedetti conferma le verit&agrave; di&shy;<lb/>mostrate gi&agrave; dal Cardano contro Aristotile, ma perch&egrave; il Tartaglia <lb/>aveva al Cardano stesso negato poter muoversi un grave nel mede&shy;<lb/>simo tempo con moto naturale e con moto violento, il Nostro sottil&shy;<lb/>mente dimostra come veramente ogni punto della traiettoria risulti <lb/>dalla composizione di quei due moti (ivi, pag. </s>

<s>365) per cui ebbe <lb/>a concludere altrove, contro ambedue, il Cardano cio&egrave; e il Tarta&shy;<lb/>glia, come per nessun suo tratto quella stessa traiettoria &egrave; retta, e <lb/>com'ella, appena uscito il proietto dal proiciente, <emph type="italics"/>cito fiat curva<emph.end type="italics"/><lb/>(ivi, pag. </s>

<s>161). </s></p><p type="main">

<s>E pur contro lo stesso Tartaglia &egrave; quella Epistola del Benedetti <lb/>che s'intitola <emph type="italics"/>De ictu bombardae,<emph.end type="italics"/> nella quale si propone a scio&shy;<lb/>gliere il quesito come mai la palla faccia pi&ugrave; gran percossa, quando <lb/>il cannone &egrave; elevato, che quando &egrave; livellato coll'orizzonte. </s>

<s>Giudica <lb/>le ragioni del Matematico bresciano <emph type="italics"/>nullius momenti<emph.end type="italics"/> (pag. </s>

<s>258) e <lb/>veramente son tali, ma n&egrave; quelle del Nostro colgono pure, questa <lb/>volta nel segno, come non colgon nel segno quelle che Galileo (Ediz. </s>

<s><lb/>naz. </s>

<s>cit. </s>

<s>Vol. </s>

<s>I, pag. </s>

<s>337-40) fedelmente ripete dal matematico ve&shy;<lb/>neziano. </s></p><p type="main">

<s>Se a queste che concernono i moti naturali e i violenti s'ag&shy;<lb/>giungano le speculazioni del Benedetti intorno alla leva angolare e <lb/>intorno al cuneo, s'argomenter&agrave; quanto gran maestro egli fosse <lb/>nella scienza del moto. </s>

<s>E perch&egrave; Galileo nelle Meccaniche s'apre <lb/>la via a trattar del piano inclinato e della vite, rimovendo l'antico <lb/>errore di Pappo, &egrave; giusto si aggiunge qui da noi come il Benedetti <pb xlink:href="020/01/124.jpg" pagenum="105"/>stesso aveva, nel Trattatello suo <emph type="italics"/>De mechanicis,<emph.end type="italics"/> rimosso gi&agrave; quel&shy;<lb/>l'errore del Matematico alessandrino, dimostrando che una sfera <lb/>grave posata su un piano orizzontale pu&ograve; rimuoversi dalla sua <lb/>quiete <emph type="italics"/>absque ulla difficultate<emph.end type="italics"/> (ivi, pag. </s>

<s>155). </s></p><p type="main">

<s>Si dice che dopo Archimede uno de'primi e principali pro&shy;<lb/>motori dell'Idrostatica fosse, in sull'entrar del secolo XVII, Simeone <lb/>Stevino, e s'attribuisce a lui il paradosso che, indipendentemente <lb/>dalla sua mole, il liquido preme secondo l'altezza sua verticale, il <lb/>fondo del vaso. </s>

<s>Ma il nostro Benedetti aveva gi&agrave; da vent'anni di&shy;<lb/>mostrato questo stesso paradosso idrostatico, applicandolo, come i <lb/>fisici moderni fanno, a spiegar l'equilibrio de'liquidi in due vasi <lb/>di varia capacit&agrave;, comunicanti. </s>

<s>Chi vuol persuadersene legga l'Epi&shy;<lb/>stola o Responso a Giovan Paolo Capra <emph type="italics"/>De machina quae aquam <lb/>impellit et sublevat<emph.end type="italics"/> a pag. </s>

<s>287-88 della citata edizione. </s></p><p type="main">

<s>Fosse stato cos&igrave; felice il Matematico del Duca di Savoia in in&shy;<lb/>vestigar le leggi delle acque correnti! Tutt'all'opposto egli incorre <lb/>in tali errori, che non si crederebbero da chi ammira la sagacia di <lb/>quell'ingegno, se al citato Responso non si vedesse, nel Libro Delle <lb/>Speculazioni, seguitar l'altro col titolo <emph type="italics"/>Nova solutio problematis de <lb/>vase pleno liquoris<emph.end type="italics"/> (pag. </s>

<s>289) a risolvere il quale ammette, come <lb/>principio notissimo e vero, che le quantit&agrave; di liquido, fluito da un <lb/>vaso di qualunque figura, sieno sempre proporzionali ai tempi. </s>

<s>In <lb/>ci&ograve; egli &egrave; tanto inferiore al Cardano, quanto in Fisica &egrave; superiore <lb/>a tutti. </s></p><p type="main">

<s>E per incominciar di l&agrave;, dove primo s'introdusse a speculare <lb/>il Cardano, si not&ograve; com'egli volesse banditi dalla scienza que'nomi <lb/>vani di fuga e di orrore del vacuo, e come, a spiegare il fatto del <lb/>vaso, dentro cui, succhiata l'aria, entra l'acqua, dicesse che questa <lb/>era attratta da quella. </s>

<s>Lo Scaligero non seppe veder dove mai rise&shy;<lb/>desse questa forza di attrazione, ma, facile a negare, null'altro in <lb/>sostanza, a supplire al difetto e a mostrare il vero, asserisce. </s>

<s>Il Tar&shy;<lb/>taglia, attendendo a quell'altro modo del rarefarsi l'aria per opera <lb/>del calore, e al fatto che pur cos&igrave; il vaso attrae l'acqua, avea pro&shy;<lb/>clamato il principio che sia propriet&agrave; del calore l'attrarre. </s>

<s>Ma il <lb/>Benedetti se ne ride, e dice esser propriet&agrave; del calore non l'attrarre <lb/>ma il dilatare. </s>

<s>Cosa poi notabile &egrave; che, estendendo questo poter di&shy;<lb/>latante a tutti i corpi, soggiunge come per via del dilatarsi e del <lb/>restringersi, al crescere e al diminuir del calore, i vasi si rompono <lb/>nelle loro parti pi&ugrave; deboli (pag. </s>

<s>27). Nelle Disputazioni sui Placiti <lb/>di Aristotile (pag. </s>

<s>194) torna su questo stesso argomento, rendendo <pb xlink:href="020/01/125.jpg" pagenum="106"/>la ragione dell'aderire cos&igrave; tenacemente che fanno alla carne le <lb/>cucurbite mediche e del salir dell'acqua o del vino ne'cannellini, <lb/>che poi servirono ad uso di termometro; ragioni che son quelle <lb/>stesse che rendeva Galileo tanti anni dopo, e delle quali si trovava <lb/>cos&igrave; soddisfatto e ammirato il Sagredo. </s></p><p type="main">

<s>N&egrave; si vuol tacer qui, a proposito degli effetti calorifici, un er&shy;<lb/>rore aristotelico emendato dal Benedetti, bench&egrave; ripetuto poi da <lb/>tutti gli addetti alla Scuola galileiana infino al Borelli. </s>

<s>Aveva detto <lb/>il Filosofo, nel II Libro Delle Meteore, che il calor del sole &egrave; che <lb/>attrae e solleva i vapori. </s>

<s>E il nostro Fisico veneziano dice, pi&ugrave; di <lb/>ottant'anni prima del Fisico messinese, che ci&ograve; &egrave; apertamente falso, <lb/><emph type="italics"/>quia sol nil aliud facit quam calefacere cuius caloris ratione ea <lb/>materia rarefit et ob rarefactionem levior facta ascendit, non quia <lb/>sursum a sole feratur,<emph.end type="italics"/> (ibi, pag. </s>

<s>194). </s></p><p type="main">

<s>Ma intorno agli effetti del raro e del denso seguita sottilmente <lb/>a disputar contro Aristotile il Nostro, e dice la ragione perch&egrave; si <lb/>condensi nell'inverno e si renda visibile il vapor acqueo esalato <lb/>dalla bocca e dalle narici degli animali (pag. </s>

<s>191) e perch&egrave; sudino <lb/>nell'estate ripieni d'acqua fresca i vasi, ridendosi dei filosofi che <lb/>dicevano quel sudore esalare attraverso ai sottilissimi pori. </s>

<s>Soggiunge <lb/>poi le notabilissime parole seguenti: &ldquo; Neque silentio involvendum <lb/>est nec Aristotilem, neque alium ex suis fautoribus animadvertisse <lb/>densum et rarum esse causam ventorum &rdquo; (pag. </s>

<s>192). Non solo <lb/>non aveva avvertito questo nessun seguace di Aristotile, ma nessun <lb/>seguace di Galileo, e dur&ograve; l'errore infin tanto che non vennero <lb/>alla luce le sepolte <emph type="italics"/>Lezioni accademiche<emph.end type="italics"/> del Torricelli, nelle quali <lb/>insegn&ograve; l'Autore, a quel modo stesso che aveva tanti anni prima <lb/>fatto il Benedetti, come dal dilatarsi dell'aria al calor del sole ave&shy;<lb/>vano origine tutti i venti. </s>

<s>Gentile &egrave; poi quell'osservazione fatta della <lb/>nuvola che produce vento al di sotto, velando e rivelando al sole <lb/>il suo raggio, secondo che si legge a pag. </s>

<s>192 del citato Libro delle <lb/>Speculazioni. </s></p><p type="main">

<s>Un'altra cosa ben assai pi&ugrave; notabile delle dette fin qui &egrave; che <lb/>il Benedetti, in tempi cos&igrave; remoti abbia tanto chiaramente veduta, <lb/>in quegli stessi effetti di rarefazione e di condensazione la causa <lb/>vera de'suoni. </s>

<s>La storia dell'Acustica rimane in certo modo umi&shy;<lb/>liata a dover narrare che un Fisico della qualit&agrave; del Montanari, <lb/>presso al fine del secolo XVII, dicesse come il suono si produce <lb/>dalla collisione dell'aria coi corpi duri. </s>

<s>Eppure il fisico veneziano <lb/>aveva un secolo avanti insegnato che l'aria corre velocemente a <pb xlink:href="020/01/126.jpg" pagenum="107"/>riempire i luoghi rimasti vacui <emph type="italics"/>unde generatur sonus quod hucusque <lb/>a nemine animadversum fuisse comperio<emph.end type="italics"/> (pag. </s>

<s>289). E pi&ugrave; sottil&shy;<lb/>mente altrove esponendo le sue speculazioni soggiunge esser neces&shy;<lb/>sario che il corpo tremi. &ldquo; Neque etiam absque aere sonus effici <lb/>potest, quia aer sonat ingrediendo velociter ad implendum locum <lb/>ut non remaneat vacuus &rdquo; (pag. </s>

<s>190). </s></p><p type="main">

<s>Se non fosse cosa certa che Giovan Batista Porta, infin dal 1558, <lb/>descrisse la camera oscura e applic&ograve; quello strumento alla teorica <lb/>della visione, diremmo che il Benedetti era ben meritevole che fosse <lb/>riserbata a lui questa primizia delle sue speculazioni. </s>

<s>Forse egli fu <lb/>il primo ad applicar la lente biconvessa al foro, per cui s'introdu&shy;<lb/>cono i raggi solari (pag. </s>

<s>270) e senza dubbio l'applicazion ch'ei ne <lb/>fa al modo del vedere per l'organo fisiologico dell'occhio (pag. </s>

<s>297), <lb/>&egrave; di ben altro scienzato dall'Autor della <emph type="italics"/>Magia Naturale.<emph.end type="italics"/></s></p><p type="main">

<s>Bench&egrave; nell'Ottica non abbia fatto il Benedetti que'gran pro&shy;<lb/>gressi che fece nell'Acustica, nella Meteorologia e in altre parti della <lb/>Fisica o pi&ugrave; difficili o pi&ugrave; importanti, non &egrave; da tacer nondimeno <lb/>la ragion ch'ei rende del color rosso negli ecclissi di Luna, desunta <lb/>dalle rifrazioni che subiscono i raggi solari che perci&ograve; entrano nel <lb/>cono ombroso (pag. </s>

<s>257) e quell'altra ragion ben pi&ugrave; nuova dello <lb/>scintillar che fanno le stelle fisse; ragione desunta dal vario indice <lb/>di refrazione degli strati aerei e vaporosi che s'interpongono fra <lb/>que'lontanissimi corpi lucidi e il proprio occhio nostro (pag. </s>

<s>186). </s></p><p type="main">

<s>Il titolo di <emph type="italics"/>Speculazioni<emph.end type="italics"/> dato al libro, d'onde tante nuove verit&agrave; <lb/>della scienza si diffondevano a illuminar le tenebre di quei tempi, <lb/>&egrave; benissimo appropriato, perch&egrave; infatti l'Autore non si contenta che <lb/>di speculare. </s>

<s>Santorre Santorio invece, nato 31 anno dopo il Bene&shy;<lb/>detti in Capo d'Istria nel 1561, &egrave; l'uomo d'azione e l'arte medica <lb/>professata da lui &egrave; che potentemente l'inclina a mettere in esercizio <lb/>le solitarie speculazioni della scienza. </s>

<s>Cos&igrave;, mentre lo stesso Bene&shy;<lb/>detti s'era contentato di specular le ragioni per cui, in un cannel&shy;<lb/>lino di vetro, condensata l'aria, vi sottentra l'acqua, e variando la <lb/>temperatura l'acqua stessa ora s'alza nel cannellino ora s'abbassa; <lb/>il Santorio pensa di sottoporre a misura quegli alzamenti e quegli <lb/>abbassamenti, per servirsene come di sicuro argomento a misurare <lb/>il giusto grado degli accessi e dei recessi ne'calori febbrili. </s>

<s>E mentre <lb/>dall'altra parte Galileo, sperimentando coi pendoli le prime leggi <lb/>della caduta dei gravi, s'accorge dell'isocronismo delle loro vibra&shy;<lb/>zioni, e accenna all'uso che se ne potrebbe far nella misura dei <lb/>minimi tempi, il Santorio pensa d'applicar quello strumento a ri-<pb xlink:href="020/01/127.jpg" pagenum="108"/>conoscer da un giorno a un altro negli infermi la frequenza dei <lb/>polsi. </s></p><p type="main">

<s>Ma di simili altri strumenti, applicabili tutti all'arte sua pre&shy;<lb/>diletta, il Santorio &egrave; inventore fecondo, e aveva gi&agrave; divisato di con&shy;<lb/>sacrare a descriverli tutti insieme un libro intero. </s>

<s>Se fosse un tal <lb/>d&igrave;visamento poi mandato ad effetto, non si sa, perch&egrave; il libro degli <lb/><emph type="italics"/>Istrumenti medici<emph.end type="italics"/> a noi non &egrave; noto. </s>

<s>&Egrave; certo per&ograve; che l'inventore <lb/>non teneva il segreto, e secondo che egli stesso scrive, la sua casa <lb/>in Padova era aperta a tutti coloro, che o per curiosit&agrave; o per amore <lb/>di scienza accorrevano a veder tutte insieme raccolte, e come in <lb/>un piccolo museo ordinate e messe in mostra, quelle sue nuove <lb/>invenzioni. </s></p><p type="main">

<s>Quali che si fossero le dottrine professate dal nostro medico <lb/>giustinopolitano, &egrave; un fatto che questa cos&igrave; feconda vena d'inven&shy;<lb/>tare e di costruire e di utilmente applicare strumenti, era una pro&shy;<lb/>testa viva e parlante contro i principii aristotelici, i quali, procla&shy;<lb/>mando la mente sovrana e legislatrice della Natura, venivano a <lb/>concluder che la mente stessa sovrasta ai sensi anco infermi e non <lb/>bisognosi perci&ograve; di aiuti. </s></p><p type="main">

<s>Che se il Santorio non sa talvolta tener monde le vesti della <lb/>mota peripatetica, non &egrave; per&ograve; che egli strascichi, come tanti suoi <lb/>pari fanno, in quel lurido fango la toga. </s>

<s>Egli non sempre forse pro&shy;<lb/>ceder&agrave; a diritto col raziocinio, ma sentendosi vacillare s'aiuta delle <lb/>esperienze delle quali &egrave; senza dubbio un insigne monumento quella <lb/><emph type="italics"/>Medicina Statica,<emph.end type="italics"/> ordinata a riformar l'arte ippocratica Chi ripensi <lb/>che quel Trattatello dettato in forma aforistica e divisato con me&shy;<lb/>todo quasi geometrico, fu scritto in tempi, in cui si soleva affogar <lb/>da tutti le idee in un mar di parole, non finir&agrave; mai di ammirare <lb/>il Santorio, il quale fu primo a concluder le regole dell'arte me&shy;<lb/>dica dal fatto fisiologico dell'insensibile traspirazione dimostrata con <lb/>tutto il pi&ugrave; rigoroso procedere del metodo sperimentale. </s></p><p type="main">

<s><emph type="center"/>XIV.<emph.end type="center"/></s></p><p type="main">

<s>E ora che abbiamo veduto come la speculativa del Benedetti <lb/>e la pratica del Santorio compiendosi preparassero le fondamenta <lb/>alla grande Instaurazione galileana, convien passare a parlare di <pb xlink:href="020/01/128.jpg" pagenum="109"/>quel terzo che aggiungemmo a que'due primi compagno, e che <lb/>dette valida mano alla stessa grande Instaurazione insieme con <lb/>Galileo. </s></p><p type="main">

<s>Non si pu&ograve; pronunziare il nome di Paolo Sarpi, senza che <lb/>l'animo di chi ascolta non esca in ammirazioni declamatorie o in <lb/>disprezzi triviali. </s>

<s>Le trivialit&agrave; e le declamazioni son l'eccesso di <lb/>que'giudizii, che sempre si fanno da coloro, i quali non ben cono&shy;<lb/>scono l'uomo giudicato. </s>

<s>E in fatti, lasciando da parte la Religione <lb/>e la Politica, per non curarsi d'altro che della scienza, a convin&shy;<lb/>cersi che il Sarpi dee essere stato mal giudicato perch&egrave; non inteso, <lb/>basta il modo come sono state pubblicate le Lettere di lui. </s>

<s>Quella, <lb/>per esemp&inodot;o, del 2 Settembre 1602 diretta a Galileo, fu per questo <lb/>lasciata addietro dall'Alb&egrave;rti perch&egrave; <emph type="italics"/>oscura e mal dettata.<emph.end type="italics"/> Il Poli&shy;<lb/>dori, nonostante, cred&egrave; bene di pubblicarla insiem con l'altre dili&shy;<lb/>gentemente raccolte in due volumi stampati nel 1863 in Firenze. </s>

<s><lb/>Ma l'oscurit&agrave;, a voler dire il vero, non dipende gi&agrave; da chi scrive: <lb/>dipende piuttosto da chi legge e non sa di qual soggetto pro&shy;<lb/>priamente si parla. </s>

<s>A chi sapesse che l'Autore citato ivi &egrave; il Gil&shy;<lb/>bert; che la questione &egrave; trattata nella Fisiologia nuova del Magnete, <lb/>che ivi trovasi disegnata la figura, alla quale il Sarpi si richiama; <lb/>le difficolt&agrave; spariscono e la scienza si vede a un tratto scaturir, <lb/>come da un arido masso, acqua viva. </s>

<s>Allo stesso modo son nella <lb/>Raccolta del Polidori aombrate le altre lettere del Sarpi, unico do&shy;<lb/>cumento pubblico, da cui si possa giudicare della scienza naturale <lb/>di lui. </s>

<s>Ma bench&egrave; sieno, in materia scientifica quelle lettere poche, <lb/>pure apparecchiano innanzi a chi ha buono stomaco da digerirlo, <lb/>cibo che nutrisce assai meglio delle pi&ugrave; squisite vivande imbandite <lb/>al pi&ugrave; liberale convito. </s>

<s>Anzi quella concisione di linguaggio scien&shy;<lb/>tifico, quasi ridotto a formule matematiche, per cui a chi non ha <lb/>acume da entrarci bene addentro pare enimmaticamente oscuro, &egrave;, <lb/>secondo noi, uno dei pregi pi&ugrave; singolari del Sarpi, di che in lui e <lb/>nel Santorio s'ha esempio unico in quei tempi </s></p><p type="main">

<s>Del resto, anco quando non s'avesse nessuna scrittura scien&shy;<lb/>tifica dell'Autore, basterebbero a testimoniar della scienza di lui le <lb/>sincere ammirazioni e le lodi dei contemporanei, fra'quali Galileo <lb/>e il Gilbert soli varrebbero per tutti gli altri. </s>

<s>Ma giacch&egrave; quelle <lb/>scritture ci sono e son vive e parlanti, studiamoci di leggerle, con <lb/>la serenit&agrave; stessa di chi nulla altro ama e null'altro vuole annun&shy;<lb/>ziar che il vero. </s></p><p type="main">

<s>Nel 1608, immerso tutto nelle faccende politiche, scriveva il <pb xlink:href="020/01/129.jpg" pagenum="110"/>di 22 Luglio al Groslot, come innanzi che le occorrenze del mondo <lb/>lo invitassero a pensar come cose serie e non come passatempi a <lb/>quelle faccende, aveva tutti i suoi gusti nelle scienze naturali e <lb/>nelle matematiche (Polidori, ivi, vol. </s>

<s>I, pag. </s>

<s>76). Qual fosse poi il <lb/>metodo ch'ei proseguiva, s'argomenta da ci&ograve; che altrove, allo stesso <lb/>Groslot scrive del non doversi filosofar, conforme al precetto di So&shy;<lb/>crate, sopra esperienze non vedute da s&egrave; proprio (ivi, pag. </s>

<s>181). In <lb/>questo modo protestava apertamente contro Aristotile, e soggiun&shy;<lb/>gendo poco appresso ch'ei sentiva qualche opposizione in trattar <lb/>cose astratte, perch&egrave; non si metteva in conto la repugnanza della <lb/>materia, mostrava di voler seguire altra via da coloro, che, fedeli <lb/>troppo a Platone, discorrevano, colle astrazioni matematiche, de'fatti <lb/>particolari della Natura. </s></p><p type="main">

<s>Fra'soggetti naturali, che pi&ugrave; vivamente richiamassero a s&egrave; <lb/>l'attenzione de'Filosofi e la voglia de'curiosi, eran que'moti irre&shy;<lb/>golari veduti fare alla calamita, i quali scoperti prima dal Colombo <lb/>furono poi confermati dalle osservazioni degli altri navigatori. </s>

<s>Cos&igrave; <lb/>il Colombo per&ograve; come Giovanni da Empoli si stettero contenti a <lb/>osservare e a descrivere i semplici fatti: il Sassetti che si volle <lb/>provare a filosofarvi sopra, assai presto se ne tolse gi&ugrave;, atterrito <lb/>dalla difficolt&agrave; del soggetto. </s></p><p type="main">

<s>Il primo che ardisse d'affrontare quelle difficolt&agrave;, predisponendo <lb/>l'ingegno alle filosofiche speculazioni colle osservazioni sensate e <lb/>colle pi&ugrave; sottili esperienze, fu il nostro Sarpi, di cui il Porta, nel <lb/>settimo libro della Mag&igrave;a raccolse per avventura gli studi e le sco&shy;<lb/>perte magnetiche, le quali sarebbero andate altrimenti con grave <lb/>danno perdute. </s></p><p type="main">

<s>N&egrave; a quella vigorosa giovent&ugrave; di mente questo fra'soggetti na&shy;<lb/>turali poteva esaurire le forze. </s>

<s>Si vuole anzi che nulla fosse dal <lb/>Sarpi lasciato addietro di ci&ograve; che allora, o in cose di fisica o in <lb/>cose di storia naturale potesse attrarre a s&egrave; l'attenzione degli in&shy;<lb/>gegni speculativi. </s>

<s>Il Grisellini, fra le altre, vorrebbe attribuirgli la <lb/>scoperta delle valvole delle vene e fargli di l&igrave; indurre l'altra pi&ugrave; <lb/>grande scoperta della circolazione del sangue. </s>

<s>E perch&egrave; l'argomento <lb/>&egrave; di troppo alta importanza, non si vuol lasciar qui da noi senza <lb/>esame. </s></p><p type="main">

<s>&ldquo; Mediante dunque le sue esercitazioni anatom&inodot;che (cos&igrave; scrive <lb/>lo stesso Grisellini di fra Paolo quando aveva 26 anni) avendo sco&shy;<lb/>perte le valvole delle vene onde la successione del sangue da que&shy;<lb/>ste nelle arterie si rende manifesta, ne veniva quinci dimostrata <pb xlink:href="020/01/130.jpg" pagenum="111"/>e stabilita la circolazione del sangue, che per alcune anteriori os&shy;<lb/>servazioni di Realdo Colombo, del Serveto e del Cesalpino era stata <lb/>accennata, egli, io dico avendo scoperte esse valvole non tacque la <lb/>sua scoperta al celebre Fabrizio d'Acquapendente, il quale, coll'oc&shy;<lb/>casione di trasferirsi in Venezia.... aveva contratto seco amicizia. </s>

<s>&rdquo; <lb/>(Mem. </s>

<s>aned. </s>

<s>Losanna 1760, pag. </s>

<s>20). </s></p><p type="main">

<s>Che il Sarpi facesse veramente soggetto di speculazioni e di <lb/>esperienze anco l'Anatomia &egrave; cosa probabilissima, ed &egrave; certo che <lb/>l'Acquapendente apprese dallo stesso Sarpi quel curioso fatto del <lb/>ristringersi e del dilatarsi delle pupille osservato gi&agrave; molto tempo <lb/>prima, senza che si sapesse, da Leonardo. </s>

<s>Ma che l'Acquapendente <lb/>apprendesse dal Sarpi, come il Grisellini asserisce, la scoperta delle <lb/>valvole delle vene, non solo non s'ha certa dimostrazione da nes&shy;<lb/>sun documento, ma i documenti che abbiamo stanno a provar tutto <lb/>il contrario. </s></p><p type="main">

<s>Il Falloppio ha un passo notabilissimo, che si vedr&agrave; trascritto <lb/>a suo luogo, dal quale apparisce che in alcune vene l'esistenza <lb/>delle valvole fu ritrovata gi&agrave; da Giovan Batista Canani. </s>

<s>La scoperta <lb/>fu divulgata da G. </s>

<s>Rodriguez conosciuto sotto il nome di Amato <lb/>Lusitano, ed &egrave; contro a lui che fieramente se la prende il Fallop&shy;<lb/>pio, asserendo che l'illustre Canano non poteva essere incorso in <lb/>un errore cos&igrave; madornale. </s>

<s>La scoperta, che in tal modo il grande <lb/>anatomico modenese lasci&ograve; scapparsi di mano, venne tutta alle mani <lb/>dell'Acquapendente, il quale con gran diligenza racconta da s&egrave; me&shy;<lb/>desimo qual fosse l'anno e a quale occasione gli occorresse di far <lb/>quella scoperta invidiata. </s></p><p type="main">

<s>Leggesi un tal racconto scritto nel Trattatello stampato in Pa&shy;<lb/>dova nel 1603 dalla tipografia di Lorenzo Pasquati. </s>

<s>Ci &egrave; nato il <lb/>sospetto che, o per la rarit&agrave; o per altra ragione quel Trattatello <lb/>dell'Acquapendente non fosse veduto mai da nessun di coloro che <lb/>lo citano, incominciando dall'alterare il titolo stesso da quello che <lb/>dall'Autore gli &egrave; imposto. <emph type="italics"/>De valvulis<emph.end type="italics"/> lo intitola il Magiotti, <emph type="italics"/>De <lb/>ostiolis sanguinis<emph.end type="italics"/> il Grisellini, <emph type="italics"/>De ostiolis venarum<emph.end type="italics"/> il Puccinotti; <lb/>ma &egrave; un fatto che il titolo vero &egrave; <emph type="italics"/>De venarum ostiolis.<emph.end type="italics"/> Non fa <lb/>perci&ograve; maraviglia se quegli autori, i quali o non poterono o non <lb/>si curarono di consultar ci&ograve; che lo scopritore delle valvole delle <lb/>vene ne scrisse, raccontano a uria e giudicano delle cose. </s></p><p type="main">

<s>Consultando per&ograve; senz'animo preoccupato quella scrittura, ci si <lb/>trova un tal carattere di verit&agrave;, nella narrazione e nella descrizione, <lb/>che il voler negar fede alle parole dell'Autore sarebbe un profes-<pb xlink:href="020/01/131.jpg" pagenum="112"/>sare addirittura il pi&ugrave; assoluto pirronismo storico. </s>

<s>Incomincia da <lb/>far le meraviglie come mai l'esistenza delle valvole delle vene po&shy;<lb/>tesse esser rimasta agli anatomici per cos&igrave; lungo tempo occulta, e <lb/>soggiunge che nel sezionare i cadaveri s'abbatt&egrave; a vederle per la <lb/>prima volta nel 1574. (De ven. </s>

<s>ost. </s>

<s>pag. </s>

<s>1). La via della scoperta <lb/>gli era stata preparata gi&agrave; da ci&ograve; che eragli occorso d'osservare <lb/>nelle vene allacciate o compresse (ivi, pag. </s>

<s>2) le quali inturgidendo <lb/>di sangue mostrano nel loro decorso certi nodi, come quei delle <lb/>canne, ond'&egrave; che mettendosi a dissecare per veder ci&ograve; che fossero <lb/>veramente quei nodi, ritrov&ograve; che egli eran dovuti a un ristagno di <lb/>sangue, operatovi dalle valvole, a quel modo che si vede fare alle <lb/>cateratte attraverso al corso di un fiume. </s></p><p type="main">

<s>Ora, &egrave; egli credibile che Girolamo Fabrizi d'Acquapendente, <lb/>nella vita sua civile e scientifica cos&igrave; dignitoso, avesse osato d'as&shy;<lb/>serire tali falsit&agrave; e di scriverle sotto gli occhi di Fra Paolo? </s>

<s>E <lb/>dall'altra parte egli invoca, a far testimonianza del vero, l'inclita <lb/>nazione Germanica, alla quale dedica il Trattatello, e nella stessa <lb/>Lettera dedicatoria ringrazia Salomone Alberto, per aver nella sua <lb/>nazione divulgata quella scoperta. </s></p><p type="main">

<s>Ritornando ora alle osservazioni del Grisellini, diciamo che, <lb/>sebbene debba credersi vero autore della scoperta delle valvole delle <lb/>vene n&ograve; il Sarpi, ma l'Acquapendente, &egrave; falso nulladimeno che i <lb/>due grandi uomini o di li o d'altronde pigliassero argomento a di&shy;<lb/>mostrar il circolo del sangue. </s>

<s>Vari passi potrebbero citarsi dalle <lb/>opere dell'Acquapendente, e specie dal cap. </s>

<s>VIII, Parte II. <emph type="italics"/>De for&shy;<lb/>mato foetu,<emph.end type="italics"/> da'quali si proverebbe com'egli, trattando degli usi <lb/>del polmone, ripete le antiche dottrine galeniche approvate gi&agrave; dal <lb/>Vesalio e dal Falloppio, nulla accettando nemmeno di ci&ograve; che, ri&shy;<lb/>spetto alla piccola circolazione, avevano dimostrato il Colombo e il <lb/>Cesalpino. </s>

<s>Dall'altra parte, per lo stesso Trattato <emph type="italics"/>De venarum ostiolis<emph.end type="italics"/><lb/>si par chiaro che l'Autore attribuiva alle valvole un ufficio ben di&shy;<lb/>verso da quello che veramente hanno in natura, il qual'&egrave; di faci&shy;<lb/>litare il corso del sangue verso il lago del cuore. </s>

<s>L'Acquapendente <lb/>infatti ammettendo che il sangue venoso abbia virt&ugrave; di alimentare, <lb/>dice che le valvole sono ordinate a distribuir quell'alimonia per <lb/>tutto equamente. </s>

<s>Che se nelle vene pi&ugrave; lontane dal centro del cuore, <lb/>come in quelle delle braccia e delle gambe, osserva le valvole ri&shy;<lb/>correre ivi pi&ugrave; spesse, non sospetta per niente che ci&ograve; sia perch&egrave; <lb/>il sangue abbisogna, in quelle condizioni, d'aiuti maggiori, avendo <lb/>a fare un viaggio pi&ugrave; lungo per tornarsene al suo principio; ma <pb xlink:href="020/01/132.jpg" pagenum="113"/>dice che, essendo le gambe e le braccia soggette a fare sforzi, per <lb/>cui il sangue correrebbevi troppo veloce, a temperarne la forza vi <lb/>bisogna un pi&ugrave; frequente uso di valvole. </s>

<s>Che poi ne anco il Sarpi <lb/>non avesse nemmen la pi&ugrave; lontana idea del circolo del sangue, <lb/>s'argomenta da alcune espressioni che ricorrono negli scritti di lui <lb/>e segnatamente ne'principii delle Lettere CXXIV e CCXX, fra le <lb/>pubblicate dal Polidori. </s></p><p type="main">

<s>Gli ammiratori ferventi del frate servita intesero a glorificarlo <lb/>altres&igrave; coll'attribuirgli l'invenzione di alcuni de'principali strumenti <lb/>del metodo sperimentale, fra'quali &egrave; il Telescopio. </s>

<s>Ma del Tele&shy;<lb/>scopio tratta il Sarpi nelle sue Lettere a varie occasioni, e ne tratta <lb/>in modo da potere informare sulle sue stesse parole il pi&ugrave; retto <lb/>giudizio. </s>

<s>In una Lettera al Groslot, che &egrave; la LII della Raccolta del <lb/>Polidori, dop'essersi fatto intendere che verso la fine del Novem&shy;<lb/>bre 1608 ebbe avviso <emph type="italics"/>delli nuovi occhiali<emph.end type="italics"/> sei mesi prima che quello <lb/>stesso avviso pervenisse alle orecchie di Galileo, soggiunge che, <lb/>quando egli era giovane, pens&ograve; ad una tal cosa e gli pass&ograve; per la <lb/>mente che un occhial fatto di figura di parabola potesse far tale <lb/>effetto. </s></p><p type="main">

<s>Le lenti paraboliche poi dettero soggetto di specular lunga&shy;<lb/>mente agli ottici infino ai tempi del Newton, nonostante che il Ca&shy;<lb/>valieri avesse geometricamente dimostrato, nel suo <emph type="italics"/>Specchio Ustorio,<emph.end type="italics"/><lb/>esser quella una inutile squisitezza, stante che, tra un menisco sfe&shy;<lb/>rico e un iperbolico, &egrave; trascurabile la differenza. </s>

<s>Ma &egrave;, in tal pro&shy;<lb/>posito assai importante una lettera del 4 Ottobre 1614, nella quale <lb/>Bartolommeo Imperiali propone a Galileo la soluzione di quell'enim&shy;<lb/>ma, che il Porta scrisse nel cap. </s>

<s>XI del XVII libro della Mag&igrave;a. </s>

<s><lb/>Quell'enimma concerne uno strumento da veder le cose lontane, <lb/>e l'Imperiali indovinerebbe che consistesse nella lente parabolica. </s>

<s><lb/>Dice ivi che il Porta, <emph type="italics"/>per quanta istanza li sia stata fatta da prin&shy;<lb/>cipi b letterati s'&egrave; potuto mai inchinare a dichiarar l'animo suo: <lb/>solo disse che maestro Paolo da Venezia servita l'aveva capito.<emph.end type="italics"/><lb/>(Mss. </s>

<s>Gal. </s>

<s>Div. </s>

<s>II, P. VI, T. IX, c. </s>

<s>206). Di qui facilmente si rac&shy;<lb/>coglie d'onde attingesse il Porta l'idea dello strumento da veder <lb/>le cose lontane, e poniamo pure che rimanesse un'idea, nonostante <lb/>non &egrave; piccola gloria di lui e del Sarpi l'aver creduto possibile il <lb/>Telescopio, a cui il gran Kepler non ebbe fede, in fin tanto che <lb/>non se lo vide fra le mani, e non ne fece esperienza con gli occhi. </s></p><p type="main">

<s>Divenuta la possibilit&agrave; in atto, per la fortunatissima opera di <lb/>Galileo, il Sarpi non rimase indietro nelle osservazioni celesti. </s>

<s>In <pb xlink:href="020/01/133.jpg" pagenum="114"/>una lettera del 16 marzo 1610, dopo aver fra Paolo annunziato al <lb/>Leschassier che pi&ugrave; di due anni fa gli Olandesi avevano scoperto <lb/>uno strumento pel quale si vedevano le cose lontane. </s>

<s>&ldquo; Di questo <lb/>trovato, soggiunge, un nostro Matematico di Padova e altri italiani <lb/>intendenti della materia principiarono a valersi per l'Astronomia, <lb/>e dalla esperienza avvalorati lo ridussero pi&ugrave; atto e perfezionato. </s>

<s>&rdquo; <lb/>(Polidori, vol. </s>

<s>II, pag. </s>

<s>41). Che quel matematico di Padova sia Ga&shy;<lb/>lileo, &egrave; fuor di dubbio, ma giacch&egrave; lo scrittore di quelle parole ci <lb/>rive&igrave;a l'importantissima notizia che cio&egrave;, contemporaneamente a <lb/>Galileo, il quale si crede da tutti il primo e il solo, ci fossero <emph type="italics"/>altri <lb/>italiani,<emph.end type="italics"/> i quali attendevano a perfezionare il canocchiale, e a far <lb/>con esso osservazioni celesti; chi sono, si domanda, questi italiani? </s>

<s><lb/>E alla domanda si risponde da noi dicendo che quegli italiani erano <lb/>appunto il Sarpi e gli altri che in Venezia conferivan con lui. </s></p><p type="main">

<s>Giunger&agrave; forse come cosa nuova ai lettori e per la novit&agrave; parr&agrave; <lb/>non credibile, che il <emph type="italics"/>Nuncio Sidereo,<emph.end type="italics"/> e quanto alle osservazioni <lb/>degli occhi, e quanto alle speculazioni della mente, sia opera tutto <lb/>insieme, e forse per egual merito, di Galileo e del Sarpi. </s>

<s>Eppure <lb/>i documenti, che ai giudiziosi e agli spassionati appariranno chia&shy;<lb/>rissimi, tolgon via intorno a ci&ograve; tutti i dubbi. </s></p><p type="main">

<s>In quella lettera al Leschassier, ora ultimamente citata, pro&shy;<lb/>segue a dire il Sarpi, a proposito delle osservazioni celesti fatte col <lb/>canocchiale, come in Toscana erano state osservate nuove cose nella <lb/>stella di Giove, che ei legger&agrave; nell'<emph type="italics"/>opuscolo<emph.end type="italics"/> offertogli a nome suo <lb/>dal Legato. </s>

<s>Quell'opuscolo era senza dubbio il Nunzio Sidereo, al&shy;<lb/>quante copie del quale Galileo, appresso allo stampatore avea rila&shy;<lb/>sciate a disposizione di Fra Paolo, che le dispensava agli amici. </s>

<s><lb/>Mentre che per&ograve; era sollecito di diffondere quel libro negli altri, <lb/>egli ancora non lo aveva letto, e nonostante torna poco dopo a <lb/>scrivere una nuova lettera allo stesso Leschassier, nella quale si <lb/>contengono annunziate le principali fra le scoperte celesti, che ve&shy;<lb/>nivano annunziate al mondo dall'opuscolo di Galileo. </s>

<s>Questo &egrave; poi <lb/>un argomento certo della verit&agrave; di quel che vedremo pi&ugrave; sotto es&shy;<lb/>sere asserito dallo stesso Sarpi, che cio&egrave; egli aveva conferito quelle <lb/>osservazioni celesti coll'Autor dell'opuscolo, per cui s'intende come <lb/>potesse render conto di quel che trattava, senza averlo letto. </s></p><p type="main">

<s>Anco quando il Nunzio Sidereo fosse andato smarrito, questa <lb/>lettera CXXXVI della citata Roccolta varrebbe a ristorar la scienza <lb/>di quella iattura, per ci&ograve; almeno che concerne le macchie della <lb/>Luna. </s>

<s>L'antico Plutarco ebbe la felicissima idea che la Luna fosse <pb xlink:href="020/01/134.jpg" pagenum="115"/>fisicamente costituita come la Terra, e aveva ad occhio distinte due <lb/>diverse qualit&agrave; di macchie, alcune variabili che egli attribuiva al&shy;<lb/>l'ombra de'monti insolati, e altre permanenti, che egli attribuiva <lb/>alla superficie dei mari. </s>

<s>Una tal novit&agrave;, fu, com'&egrave; naturale, rifiu&shy;<lb/>tata dai Peripatetici, ma i pi&ugrave; sagaci che vi sentiron dentro alitare <lb/>un soave spirito di verit&agrave;, l'accolsero con amore. </s>

<s>Dubitavano per&ograve; <lb/>se pi&ugrave; di luce si dovesse rifletter dai mari o dai continenti. </s>

<s>Il pro&shy;<lb/>blema veramente era illusorio e vi rimase preso anco il Keplero, <lb/>che lietamente accogliendo i placiti del Cheronese <emph type="italics"/>hac in parte,<emph.end type="italics"/><lb/>soggiunge, <emph type="italics"/>non assentior. </s>

<s>Magis est consentaneum quae sunt in <lb/>Luna partes lucidae maria credi, quae maculosae terras, conti&shy;<lb/>nentes et insulas.<emph.end type="italics"/> (Paralip. </s>

<s>edit. </s>

<s>cit. </s>

<s>pag. </s>

<s>201). Galileo nel <emph type="italics"/>Nuncio<emph.end type="italics"/><lb/>esce destramente dalla controversia saettando simili parole: &ldquo; La <lb/>terra dee apparir pi&ugrave; chiara del mare, e intorno a ci&ograve; <emph type="italics"/>mihi dubuim <lb/>fiut unquam.<emph.end type="italics"/> &rdquo; (Alb. </s>

<s>III, pag. </s>

<s>65). </s></p><p type="main">

<s>Che il Keplero alla contraria sentenza, cos&igrave; laconicamente pro&shy;<lb/>nunziata da Galileo, ne rimanesse persuaso, e tornasse anco per <lb/>questa parte al suo Plutarco, non fa maraviglia. </s>

<s>Fa per&ograve; maraviglia <lb/>il sentirlo dire che fu condotto in quella persuasione di creder cio&egrave; <lb/>mari le macchie della luna, da ci&ograve; che ne disse Galileo stesso <emph type="italics"/>di&shy;<lb/>sputatione exactissima<emph.end type="italics"/> e di pi&ugrave; <emph type="italics"/>illatione argutissima et invicta.<emph.end type="italics"/><lb/>(Alb. </s>

<s>V, 418, 19) mentre Galileo nel <emph type="italics"/>Nuncio<emph.end type="italics"/> tutt'altro che dispu&shy;<lb/>tare e argomentare, si sta contento ad asserir semplicemente il fatto <lb/>che egli tiene anzi cos&igrave; certo, da non aver bisogno alcuno di prove. </s></p><p type="main">

<s>Chi veramente disputa su tale importante soggetto e argomenta <lb/>&egrave; il Sarpi, nella citata lettera al suo Leschassier e le disputazioni <lb/>e gli argomenti son suggellati dalla esperienza. </s>

<s>&ldquo; Se Ella porr&agrave; di <lb/>contro al sole ma lungi da s&egrave; una pietra rotonda e uno specchio <lb/>sferico della stessa grandezza, vedr&agrave; l'emisfero della pietra rischia&shy;<lb/>rato e tutto lo specchio oscuro, all'infuori di quella minima parti&shy;<lb/>cella, in cui le si offrir&agrave; alla vista un certo piccol sole. </s>

<s>Che se <lb/>tanto l'allontaner&agrave; da essere insensibile l'angolo, cio&egrave; quel piccol <lb/>sole, appena Ella vedr&agrave; lo specchio; il sole poi apparir&agrave; splendi&shy;<lb/>dissimo. </s>

<s>L'acqua e la terra sono sferiche e la Luna ha una parte <lb/>lucida ed una macchiata: applichi ad essa questi riflessi e toccher&agrave; <lb/>con mano la cosa. </s>

<s>&rdquo; (Polidori, vol. </s>

<s>II, pag. </s>

<s>63). </s></p><p type="main">

<s>Galileo non argomenta n&egrave; disputa intorno alla ragion fisica <lb/>delle macchie permanenti della Luna, se non parecchi anni dopo <lb/>nel primo Dialogo dei Due Massimi Sistemi (Alb. </s>

<s>I, 15, 88) ricor&shy;<lb/>rendo all'esperienza dello specchio sferico e della pietra scabrosa <pb xlink:href="020/01/135.jpg" pagenum="116"/>o del muro, a quel modo che aveva fatto gi&agrave; il Sarpi nelle lettere <lb/>e nelle parole sopra trascritte ond'&egrave; che non a torto si pu&ograve; quella <lb/>stessa lettera al Leschassier riguardar come un trattatello d'Astro&shy;<lb/>nomia fisica lunare, pi&ugrave; compiuto del Nuncio Sidereo. </s></p><p type="main">

<s>A chi rifletta con giudiziosa mente a queste cose non sembrer&agrave; <lb/>perci&ograve; alieno dal vero quel che s'asseriva di sopra, che cio&egrave; in <lb/>gran parte si debbano al Sarpi le novit&agrave; scoperte e annunziate da <lb/>Galileo. </s>

<s>La nostra asserzione poi fondata sui fatti d&agrave; suggello di <lb/>verit&agrave; alle parole con le quali fra Paolo, accennando al matematico <lb/>dello studio di Padova esordisce il suo compendioso Nunzio Astro&shy;<lb/>nomico: &ldquo; Spesso abbiamo conferito insieme su quell'argomento e <lb/>molte osservazioni ci scambiammo. </s>

<s>&rdquo; (Polid. </s>

<s>vol. </s>

<s>II, pag. </s>

<s>61). </s></p><p type="main">

<s>Ed ecco insieme i fatti stessi confermare altri detti citati pi&ugrave; <lb/>sopra a proposito di quegli italiani che attendevano in Venezia a <lb/>perfezionare il canocchiale e a far con esso osservazioni celesti. </s>

<s>A <lb/>quel numero appartenevano gli eruditi di cui il Sarpi scrive nella <lb/>lettera CXLI, i quali comprendendo che mal si sarebbe riusciti a <lb/>perfezionare il canocchiale senza prima conoscerne le teorie, dise&shy;<lb/>gnavano di fare un piccolo commentorio sulla visione <emph type="italics"/>ove esporranno <lb/>la maniera e la cagione del trovato olandese<emph.end type="italics"/> (ivi, pag. </s>

<s>81). Nel&shy;<lb/>l'agosto 1610 quel Commentario, che senza dubbio &egrave; il Trattato <lb/>del De Dominis <emph type="italics"/>De radiis visus et lucis,<emph.end type="italics"/> non era ancora finito di <lb/>stampare e si attendeva a mettere all'ordine le incisioni (ivi, <lb/>pag. </s>

<s>108). </s></p><p type="main">

<s>A chi poi si maravigliasse come mai l'Autore del Nunzio Si&shy;<lb/>dereo non facesse il pi&ugrave; piccolo accenno al suo collaboratore nelle <lb/>osservazioni celesti, si risponder&agrave; pi&ugrave; avanti, quando altri simili <lb/>fatti ci faranno meglio conoscere un'indole propria di Galileo. </s>

<s>Ba&shy;<lb/>sti r&igrave;sponder per ora che, nella prima lettera familiare la quale <lb/>gli occorresse di scrivere al Sarpi dopo la pubblicazione del Mes&shy;<lb/>saggero, Galileo ne esalta le virt&ugrave; e i meriti e professa di tenergli <lb/>obblighi infiniti (Alb. </s>

<s>VI, 141). </s></p><p type="main">

<s><emph type="center"/>XV.<emph.end type="center"/></s></p><p type="main">

<s>Chi si rivolge indietro a comprendere in una occhiata sola la <lb/>lunga schiora passata da noi fin qui in rassegna, da Dante Alighieri <lb/>a Paolo Sarpi, non pu&ograve; non restar sorpreso da maraviglia, e non <pb xlink:href="020/01/136.jpg" pagenum="117"/>confessare a s&egrave; medesimo ch'ei non l'avrebbe creduta mai n&egrave; s&igrave; <lb/>eletta, n&egrave; s&igrave; numerosa. </s>

<s>Essa rimane ancora immobile sotto lo sguardo <lb/>dei nostri lettori e par che voglia star l&igrave; a fronte alta per chieder <lb/>ragione e vendicar l'accusa che fu data a loro da tanti d'esser e <lb/>vissuti cio&egrave; in secoli di barbarie, e di non aver saputo cacciar di&shy;<lb/>nanzi a s&egrave; le tenebre dell'ignoranza. </s>

<s>A chi li rimprover&ograve; e gli <lb/>compianse, perch&egrave; avessero tenute aggiogate le loro cervici sotto <lb/>l'autorit&agrave; di Aristotile, e non avessero saputo far altro che ridire <lb/>in prosa gli errori declamati da lui, rispondono squadernando in&shy;<lb/>nanzi agli occhi i loro volumi, e accennando colla punta del dito <lb/>alle nuove speculazioni e alle nuove scoperte, frutto di libera filo&shy;<lb/>sofia e d'ingegnosa arte sperimentale. </s></p><p type="main">

<s>Si sentiva nonostante in sul primo entrar del secolo XVII che <lb/>i frutti menati dall'albero della scienza non rispondevano, n&egrave; in <lb/>qualit&agrave;, n&egrave; in numero, all'abbondanza dei rami, per cui fu creduto <lb/>si potesse utilmente provvedere alla loro ubert&agrave; col moitiplicare i <lb/>cultori a ci&ograve; chiamati ed eletti. </s>

<s>Un tal pensiero accolto in un animo <lb/>generoso e che per opera di un Principe romano d'animo non <lb/>men generoso si pot&egrave; mettere in atto, di&egrave; luogo all'istituzione del&shy;<lb/>l'Accademia de'Lincei, la seconda forse, che dopo la Platonica fio&shy;<lb/>rentina, si vedesse in Italia. </s></p><p type="main">

<s>Il principio informativo della nuova Accademia &egrave; notabile che <lb/>si desumesse dall'istituzione dei Cherici regolari, e che, come questi <lb/>si proponevano di diffonder la fede cristiana e i buoni costumi, cos&igrave; <lb/>gli Accademici lincei si proponessero di diffonder la scienza natu&shy;<lb/>rale e i retti metodi sperimentali. </s>

<s>Il <emph type="italics"/>Linceografo<emph.end type="italics"/> infatti s'assomi&shy;<lb/>glia molto alle regole dei frati, i Collegi lincei ai conventi, e l'isti&shy;<lb/>tuzione delle colonie lincee alle Missioni. </s>

<s>Di qui &egrave; che avendo le <lb/>leggi stesse e le costituzioni risentendo molto dell'aristotelico e ci&ograve; <lb/>vuol dire del gretto e del compassato, male erano atte a predisporre <lb/>quel nobile e generoso consesso al libero filosofare, e a coglier quei <lb/>buoni frutti, che si ripromettevano le speranze del Principe insti&shy;<lb/>tutore. </s></p><p type="main">

<s>Ben assai pi&ugrave; efficaci erano stati e duravano tuttavia ad esser <lb/>gli influssi dell'Accademia platonica, bench&egrave; non facesse professione <lb/>di scienze naturali, ma di sola Filosofia speculativa. </s>

<s>Tommaso Cam&shy;<lb/>panella, in una sua lettera del d&igrave; 6 Luglio 1628 al Granduca Fer&shy;<lb/>dinando, dice che noi italiani &ldquo; portiamo grande obbligo ai Principi <lb/>medicei, che facendo comparire i libri platonici in Italia, non visti <lb/>da'nostri antichi, fur cagione di levarci dalle spalle il giogo d'Ari-<pb xlink:href="020/01/137.jpg" pagenum="118"/>stotile, e per conseguenza poi tutti i sofisti, e cominci&ograve; l'Italia ad <lb/>esaminare la Filosofia delle Nazioni con ragione ed esperienza nella <lb/>Natura, e no nelle parole degli uomini &rdquo; (MSS. Cim. </s>

<s>T. XXVI, c. </s>

<s>13). <lb/>La cosa &egrave; tanto vera che ha il suo pieno riscontro nei fatti da noi <lb/>discorsi e pi&ugrave; in quelli che si discorreranno fra poco. </s></p><p type="main">

<s>Ma per tornare all'Accademia de'Lincei, le intenzioni, per quanto <lb/>generose fossero, dello Stelluti e del Cesi, tornarono vane, perch&egrave; <lb/>principalmente non era quella l'opportunit&agrave; n&egrave; il bisogno richie&shy;<lb/>deva di convocare un Accademia. </s>

<s>Il difetto che si ritrovava allora <lb/>nell'albero della scienza era quello stesso, che si vede negli alberi <lb/>naturali, quando per lunga et&agrave; son trascorsi, a rimediare ai quali, <lb/>invece di moltiplicare i rami alla chioma e i polloni al piede, con&shy;<lb/>vien reciderli, e in un tronco solo avviar l'alimento e fomentarvi <lb/>gli spiriti vitali. </s>

<s>Non una Repubblica in altre parole conveniva isti&shy;<lb/>tuire, ma un Regno assoluto, in cui risedesse la tirannica potest&agrave; <lb/>nelle mani di un solo. </s>

<s>Ci&ograve; non poteva ottenersi che per via di una <lb/>conquista, la quale veramente fu tentata in Inghilterra da Francesco <lb/>Bacone, ma con poco felice riuscita, si consegu&igrave; in parte da Renato <lb/>Cartesio in Francia, e Galileo Galilei in Italia riport&ograve; la completa <lb/>vittoria. </s></p><p type="main">

<s>Francesco Bacone dette al suo nuovo Regno scientifico il nome <lb/>d'<emph type="italics"/>Instauratio Magna,<emph.end type="italics"/> e si cred&egrave; di dover esserne investito Monarca, <lb/>per avere architettata l'Enciclopedia d'ogni scienza e arte nel libro <lb/><emph type="italics"/>De augmentis scientiarum,<emph.end type="italics"/> e per aver nel <emph type="italics"/>Novum Organum<emph.end type="italics"/> minu&shy;<lb/>tamente divisate le regole da seguirsi nel metodo sperimentale. </s>

<s>&Egrave; <lb/>facile per&ograve; persuadersi che quella sua Monarchia non era altro che <lb/>di un nome vuoto, o se si vuole, di un regno gi&agrave; trapassato. </s>

<s>Se, <lb/>infatti, scienza veramente non ci &egrave;, e non ci &egrave; stata mai, come <lb/>vuole Bacone, egli divisa dunque nella sua Enciclopedia i loculi <lb/>senza avere di che riempirli. </s>

<s>E dall'altro lato le regole di un arte <lb/>suppongono gi&agrave; l'istituzione dell'arte stessa. </s>

<s>Cos&igrave;, dopo gli scrittori, <lb/>venne la Grammatica, dopo i pittori le regole per l'arte della pit&shy;<lb/>tura e dopo i gran capitani le regole dell'arte della guerra. </s>

<s>N&egrave; <lb/>l'arte di sperimentare pu&ograve; perci&ograve; trascendere da questa legge uni&shy;<lb/>versale: ella pure suppone sperimentatori dei fatti naturali. </s>

<s>Ma nes&shy;<lb/>suno, dice il Barone di Verulamio, ha saputo fin qui sperimentare <lb/>e osservare, e se qualcuno vi s'&egrave; provato mai, avendo sbagliato <lb/>via, non pu&ograve; assicurarsi di riuscire a trovar qualche cosa di nuovo. </s></p><p type="main">

<s>Niccol&ograve; Copernico ha contemplato da filosofo il cielo, ma a noi <lb/>giova meglio di contemplarlo alla maniera del volgo, senza punto <pb xlink:href="020/01/138.jpg" pagenum="119"/>badare a quel che se ne dicano gli astronomi, o a quel che s'in&shy;<lb/>segni nelle scuole, che senza ragione, bene spesso, godono di con&shy;<lb/>tradire al senso con sofisticherie (Nov. </s>

<s>Org. </s>

<s>Lib. </s>

<s>II, &sect; 36). Altrove, <lb/>nel IV libro <emph type="italics"/>De augmentis scientiarum,<emph.end type="italics"/> dice che la sentenza coper&shy;<lb/>nicana, come non repugnante alle apparenze, non si pu&ograve; confutar <lb/>co'principii astronomici, ma si pu&ograve; bene coi principii della Filosofia <lb/>naturale <emph type="italics"/>recte positis<emph.end type="italics"/> (Lugani 1763, pag. </s>

<s>235). Si capisce bene che <lb/>i principii della Filosofia naturale invocati qui erano quegli stessi <lb/>de'peripatetici contradittori del Copernico e del Galilei. </s></p><p type="main">

<s>Il qual Galilei, prosegue a dire il Cancellier d'Inghilterra, ha <lb/>inventato un nuovo maraviglioso strumento, con cui &egrave; ruscito a <lb/>scoprir ne'cieli cose non pi&ugrave; vedute, ma chi potrebbe con sicurezza <lb/>prestargli fede? </s>

<s>Il mio sospetto nasce principalmente dal veder <lb/>poche osservazioni, mentre se ne sarebbero potute far moltissime <lb/>in una innumerevole variet&agrave; di oggetti (Nov. </s>

<s>Org. </s>

<s>Lib. </s>

<s>II, &sect; 39). <lb/>In questo stesso errore dice di essere incorso il connazionale suo <lb/>Guglielmo Gilbert, il quale, da ripetute esperienze sopra un soggetto <lb/>solo, volle dedurne una filosofia generale, sull'esempio di Aristotile, <lb/>e perci&ograve; una filosofia fantastica e povera, qual &egrave; quella che deriva&shy;<lb/>rono i chimici dai loro alambicchi (ivi, Lib. </s>

<s>I, &sect; 44). Egli, il Gilbert, <lb/>dur&ograve; tanta fatica e us&ograve; tanta diligenza per venire a capo di uno <lb/>sperimento particolare intorno alla calamita, come gli alchimisti <lb/>intorno all'oro (ivi, &sect; 70). </s></p><p type="main">

<s>Ne &egrave; solo il male che nessuno fin qui abbia seguito il retto <lb/>filosofare, il peggio si &egrave; che Bacone prevede e presagisce che, anco <lb/>quando gli uomini eccitati da'suoi impulsi, si daranno seriamente <lb/>all'esperienza, rinunziando alle sofistiche dottrine, nonostante, per <lb/>la fretta e ansiet&agrave; del loro intelletto voglioso di volare alle gene&shy;<lb/>ralit&agrave;, le loro filosofie soggiaceranno inevitabilmente a grave pe&shy;<lb/>ricolo (ivi, &sect; 74). Per Bacone insomma, non solo non ci &egrave; stato mai <lb/>scienza e non ci &egrave;, ma prevede e presagisce che nemmen ci sar&agrave;. </s>

<s><lb/>Ci&ograve; che vuol dire per noi che il suo Regno non &egrave; e non &egrave; per <lb/>venire. </s></p><p type="main">

<s>Potrebbe esser per&ograve; che egli pretendesse di costituire il regno <lb/>della scienza col suo proprio intelletto, e perci&ograve; giova investigarne <lb/>le dovizie e mostrar quali e quante elle sono. </s></p><p type="main">

<s>Nel secondo libro del Nuovo Organo al &sect; 45 descrive per ve&shy;<lb/>rit&agrave; alcune poche esperienze, delle quali per&ograve; nessuna ha l'impronta <lb/>di originale, da quella infuori, forse, della incompressibilit&agrave; del&shy;<lb/>l'acqua rinchiusa dentro una sfera di metallo, che fortemente com-<pb xlink:href="020/01/139.jpg" pagenum="120"/>pressa da un torchio, deformata trasuda. </s>

<s>Delle altre esperienze, come <lb/>di quella dell'aria che estratta per succhiamento dall'uovo filosofico, <lb/>d&agrave; luogo a sottentrarvi spontaneamente l'acqua, gli esempii sono anti&shy;<lb/>chi, e risalgono al Cardano, anzi pi&ugrave; su, fino ad Herone di Alessandria. </s></p><p type="main">

<s>Rispetto alle varie forze sollecitanti la materia, non si puo la&shy;<lb/>sciar di notare quelle sottili osservazioni, che ricorrono in questo <lb/>stesso II libro al &sect; 25, relative alle propriet&agrave; che hanno l'acqua e <lb/>l'aria, ridotte in minime particelle, di attrarsi a vicenda; e l&agrave; dove <lb/>al &sect; 36 entra a parlar de'proietti, non &egrave; priva certo di sottilit&agrave; <lb/>l'esperienza citata delle lamine elastiche, per provar che la forza <lb/>d'impulso non vien dall'aria. </s>

<s>Ma quelle tante distinzioni di moti <lb/>ridotte in numero di diciannove, qui nel &sect; 48, sono il parto e il <lb/>portato di una filosofia, che non &egrave; punto varia dalla aristotelica. </s></p><p type="main">

<s>Del resto, per quanto &egrave; a noi noto, non ha il Verulamio, in <lb/>soggetto di scienze fisiche e sperimentali, pubblicato altro libro da <lb/>quello in fuori che s'intitola <emph type="italics"/>Historia naturalis et experimentalis <lb/>de ventis.<emph.end type="italics"/> Giacch&egrave; dunque egli ha raccolto dentro a queste pagine <lb/>tutto il frutto de'suoi metodi elaborati, il sapore attester&agrave; della <lb/>bont&agrave; dell'albero che gli ha prodotti. </s>

<s>N&egrave; la prima vista, per verit&agrave; <lb/>ci d&agrave; liete speranze. </s>

<s>Quelle distinzioni di distinzioni prolisse e <lb/>ignude, come di ramo che si divide, e suddivide poi in rami aridi <lb/>e brulli, con qualche ciuffo di foglie in sulle cime, ci assicurano <lb/>non per altro esser venuto l'Autore a sconfiggere Aristotile, che per <lb/>indossare le stesse sue divise. </s>

<s>Che poi egli ne abbia di pi&ugrave; imbe&shy;<lb/>vuti gli spiriti si parr&agrave; dall'esame delle dottrine. </s></p><p type="main">

<s>La causa generale dei venti, egli dice, &egrave; il moto del cielo, <lb/>che rapisce e mena seco in volta la sfera dell'aria. </s>

<s>Sotto i tropici, <lb/>per essere i circoli maggiori, il vento generale &egrave; pi&ugrave; manifesto, ma <lb/>non &egrave; per&ograve; che non dia luogo ai venti particolari. &ldquo; Si quis sit talis <lb/>ventus generalis ex ordine motus coeli, non adeo firmus est quin <lb/>ventis particularibus cedat. </s>

<s>Manifestior est autem intra tropicos <lb/>propter circulos quos conficit maiores &rdquo; (Lugd. </s>

<s>Batav. </s>

<s>1648, pa&shy;<lb/>gina 15). In fin qui per&ograve; non si sente nulla di nuovo, vi si ripete <lb/>la Fisica antica divinamente cantata dall'Alighieri, nella terzina 35 <lb/>e 36 del XXVIII del Purgatorio. </s></p><p type="main">

<s>Pi&ugrave; avanti per&ograve;, trattando dei venti particolari o delle <emph type="italics"/>brezze,<emph.end type="italics"/><lb/>aveva sentita la possibilit&agrave; che v'abbia anche parte a produrle il <lb/>calor del sole, <emph type="italics"/>quia calor omnem aerem dilatat.<emph.end type="italics"/> Proseguendo poi a <lb/>ragionare, questa tal possibilit&agrave; gli si converte in certezza, affer&shy;<lb/>mando che senza dubbio &egrave; il sole causa efficiente e primaria della <pb xlink:href="020/01/140.jpg" pagenum="121"/>massima parte dei venti, operando per via del calore sopra duplice <lb/>materia, <emph type="italics"/>corpus scilicet aeris et vapores sive exhalationes<emph.end type="italics"/> (ivi, pa&shy;<lb/>gina 53). Che sia veramente il calore efficace a produrre il vento <lb/>dice di averlo sperimentato in una torricella chiusa, dentro alla <lb/>quale ardeva un buon fuoco, osservando che girava un molinello <lb/>fatto di piume sospeso a un filo, e che usciva fuori con forza il <lb/>fiato da uno spiraglio. </s></p><p type="main">

<s>Che poi sia varia la materia de'venti, aria cio&egrave; e vapori, e che <lb/>da ci&ograve; si produca variet&agrave; di effetti, intende a provarlo pure col&shy;<lb/>l'esperienza, rinchiudendo nella medesima torricella, un vaso pieno <lb/>d'acqua bollente, che esala vapori in copia. </s>

<s>Dice di avere osservato <lb/>che il molinello girava ancora mosso dal fumo, per&ograve; pi&ugrave; languida&shy;<lb/>mente assai di quando ardeva il fuoco vivo, e l'esalazione spiritosa <lb/>era secca. </s>

<s>Ond'egli cos&igrave; conclude: &ldquo; Itaque excitationes motus in <lb/>ventis causa est praecipua superesoneratio aeris ex nova acces&shy;<lb/>sione aeris facti ex vaporibus &rdquo; (ivi, pag. </s>

<s>65). </s></p><p type="main">

<s>Che si pu&ograve; ora egli giudicare di questa teoria, se non che ad <lb/>essa manca un principio generale che l'informa, rimanendo, al <lb/>modo aristotelico, sminuzzata ne'fatti particolari? </s>

<s>Bacone insomma <lb/>non seppe sollevarsi a veder quel che chiarissimamente poi vide il <lb/>Torricelli, che cio&egrave; dai condensamenti e dalle dilatazioni dell'aria <lb/>prodotte dal variar dell'intensit&agrave; calorifica del sole, hanno, come <lb/>da causa generale semplice e unica, origine ogni sorta di venti. </s></p><p type="main">

<s>Il tesoro dunque del gran Cancelliere non par che sia troppo <lb/>dovizioso, almeno quanto a scienza sperimentale. </s>

<s>Che se si fosse <lb/>dovuta una tale scienza promuovere da lui solo, potremmo star si&shy;<lb/>curi che la non avrebbe fatto nemmeno un passo per uscir fuori <lb/>de'libri del Filosofo antico. </s>

<s>Molti che convengono in questo giudizio, <lb/>danno per&ograve; il merito all'Autor <emph type="italics"/>De augmentis<emph.end type="italics"/> d'aver profondamente <lb/>filosofato intorno alle ragioni de'progressi sperimentali. </s>

<s>N&egrave; ci&ograve; si <lb/>nega da noi, si vuol dir solo che spesso, in queste stesse filosofiche <lb/>speculazioni, manca quel giudizioso acume e quell'ampiezza di ve&shy;<lb/>dute, che qualificano i veri innovatori della scienza. </s>

<s>Si veda, per <lb/>esempio quel che nel cap. </s>

<s>IV del III libro dice delle cause finali. </s>

<s><lb/>Che queste, sostituendosi alle cause fisiche e reali, abbiano vera&shy;<lb/>mente indugiati i progressi della scienza, si comprende assai facil&shy;<lb/>mente e si consente da tutti. </s>

<s>Non si consente per&ograve; al Verulamio <lb/>il dir che, nella filosofia di Aristotile e di Platone, s'inculcano quelle <lb/>cause finali allo stesso modo, contentandosi di ammetter come sola <lb/>differenza una reit&agrave; maggiore nel discepolo che nel maestro. </s></p><pb xlink:href="020/01/141.jpg" pagenum="122"/><p type="main">

<s>Ma il vero si &egrave;, che le cause finali son parto legittimo ed esclu&shy;<lb/>sivo della filosofia aristotelica, di quella filosofia cio&egrave; che accomoda <lb/>la Natura ai cervelli. </s>

<s>Perch&egrave;, secondo il Cremonino, non possono <lb/>esistere i satelliti di Giove? </s>

<s>Perch&egrave; non s'intenderebbe altrimenti <lb/>quali potessero essere i loro influssi. </s>

<s>Perch&egrave; il canal toracico si <lb/>nega dal Riolano? </s>

<s>Perch&egrave; non s'intende come mai il chilo crudo <lb/>e non concotto nel fegato debba, per una via lunga, risalir su fino <lb/>alla vena cava ascendente, mentre pel fegato e per la cava discen&shy;<lb/>dente la via &egrave; tanto pi&ugrave; facile e pi&ugrave; spedita. </s></p><p type="main">

<s>La Filosofia di Platone, che ammetteva Dio legislatore della <lb/>Natura, non era punto favorevole, n&egrave; come vuol Bacone, inculcava <lb/>le cause finali, ma l&agrave; dove le cause fisiche riuscivano ignote, s'at&shy;<lb/>tribuivano gli effetti immediatamente a Dio stesso Prima Causa <lb/>universale. </s>

<s>Ora, se ben si osserva, &egrave; conforme ai placiti di questa <lb/>Filosofia il processo storico <emph type="italics"/>De augmentis scientiarum.<emph.end type="italics"/> Cos&igrave; per <lb/>esempio in fatto di Cosmoteoria, la scienza antica attribuiva il moto <lb/>circolare de'pianeti immediatamente alla mano di Dio, che gli so&shy;<lb/>stenta e gli mantiene ne'loro orbi. </s>

<s>Il Boulliaud dopo Galileo intro&shy;<lb/>dusse il moto naturale de'corpi cadenti, e il Borelli il principio <lb/>delle forze centrali, ma &egrave; sempre il dito di Dio che volge i moti <lb/>diretti in circolari, e determina a suo placito l'eccentricit&agrave; delle <lb/>orbite ellittiche. </s>

<s>Il Newt&ograve;n poi dimostra che quella eccentricit&agrave; &egrave; <lb/>determinata dal grado dell'intension delle forze attrattive e repul&shy;<lb/>sive. </s>

<s>Cos&igrave;, progredendo la scienza col sostituire via via la cause fisiche <lb/>e particolari, non si sent&igrave;, ai tempi del Filosofo inglese, bisogno di <lb/>ricorrere alla Causa prima per altro, che per ispiegiar l'origine <lb/>dell'attrazione universale. </s>

<s>Par che con simile processo la scienza <lb/>insegua e cacci dalla Natura Iddio, ma non fa in sostanza che ri&shy;<lb/>durlo sempre pi&ugrave; su nella Maest&agrave; della sua sede. </s></p><p type="main">

<s>Grande &egrave; dunque la differenza tra le due filosofie, che il Ve&shy;<lb/>rulamio accusa della medesima colpa, e il non avere avvertito questa <lb/>tal differenza, &egrave; uno di que'difetti notabili in un filosofo, il quale <lb/>vuole insegnare al mondo ignorante il modo d'investigar le vie, <lb/>che conducon la mente dell'uomo o a scoprir la verit&agrave; o a cader <lb/>nell'errore. </s></p><p type="main">

<s>Dalle cose fin qui discorse perci&ograve; si conclude che il vantato <lb/>Instauratore inglese non promosse veramente le scienze sperimen&shy;<lb/>tali, n&egrave; coll'esempio n&egrave; colle dottrine. </s>

<s>Ma non per questo si po&shy;<lb/>trebbe con giustizia asserire che i libri scritti da lui non avesser <lb/>nessuna efficacia, specie sulla mente de'suoi connazionali. </s>

<s>Il Boyle, <pb xlink:href="020/01/142.jpg" pagenum="123"/>l'Hook il Wren si sentirono venir l'impulso a filosofare dalla let&shy;<lb/>tura di que'libri, ma niente altro &egrave; che la loro facondia, la quale <lb/>gli commuove: &egrave; quella voce potente di un che grida nella solitu&shy;<lb/>dine: lasciate i sofismi e studiate la Natura. </s>

<s>Di questa efficacia in <lb/>fuori, che egli ebbe sui contemporanei e sui discendenti, Bacone &egrave; <lb/>un filosofo de'tempi passati imbevuto di quegli spiriti aristotelici, <lb/>che egli, sotto le forme di un razionalismo medio fra quello del <lb/>Campanella e del Patrizio, largamente diffonde in tutti i suoi libri. </s>

<s><lb/>All'albero perci&ograve; della scienza, per troppo lunga et&agrave; trascorso e <lb/>infiacchito, non solo egli non ha saputo trovare efficace rimedio da <lb/>ringiovanirlo, ma ne ha di pi&ugrave; esaurite le forze col moltiplicare le <lb/>sterili fronde sul ramo vecchio. </s>

<s>Sicch&egrave; non riman che l'opera sola <lb/>fatta da Galileo e dal Cartesio, l'azion de'quali che ora si vuol <lb/>mettere in vista de'nostri lettori, fa mutare scena alla rappresen&shy;<lb/>tazione di questo Dramma. </s></p><pb xlink:href="020/01/143.jpg" pagenum="124"/><p type="main">

<s><emph type="center"/><emph type="italics"/>Nota I relativa a pag. </s>

<s>69 lin. </s>

<s>19.<emph.end type="italics"/><emph.end type="center"/></s></p><p type="main">

<s>Di questi problemi, ci piace qui di recarne uno per saggio ai nostri lettori, e ab&shy;<lb/>biamo scelto il seguente, a mostrar come si possa rendere pi&ugrave; compiuta la illustrazione <lb/>data nella prima delle <emph type="italics"/>Lettere astronomiche<emph.end type="italics"/> credute di Galileo, e pubblicate, da pa&shy;<lb/>gina 135-44, negli <emph type="italics"/>Studii sulla Divina Commedia<emph.end type="italics"/> da Ottavio Gigli (Firenze, Le Mon&shy;<lb/>nier, 1885). </s></p><p type="main">

<s><emph type="center"/><emph type="italics"/>Problema di Astronomia dantesca:<emph.end type="italics"/><emph.end type="center"/><lb/>Si come quando i primi raggi vibra, <lb/>La dove il suo Fattore il sangue sparse <lb/>(Cadendo Ibero sotto l'alta libra). <lb/>E l'onde in Gange, da nona riarse; <lb/>Si stava il Sole; onde il giorno sen gia, <lb/>Quando l'Angel di Dio lieto ci apparse. </s></p><p type="main">

<s><emph type="center"/><emph type="italics"/>(Purg.,<emph.end type="italics"/> C. XXVIII, t. </s>

<s>1, 2).<emph.end type="center"/></s></p><p type="main">

<s>Posto che, a muovere dall'Isole Fortunate, ora Canarie, la longitudine della fonte <lb/>dell'Ibero sia 12&deg; 30&prime;, e 16&deg; la longitudine della sua foce; posto che sia 66&deg; la longi&shy;<lb/>tudine di Gerusalemme, e 148&deg; 30&prime; quella della foce pi&ugrave; orientale del Gange; si domanda <lb/><emph type="italics"/>come stava,<emph.end type="italics"/> secondo la descrizione fattane dal Poeta, il sole rispetto all'orizzonte del <lb/>Purgatorio o di Gerusalemme? </s></p><p type="main">

<s>Rappresenti il gran cerchio AEDF (fig. </s>

<s>I) l'Equatore celeste, e il piccolo cerchio <lb/><figure id="id.020.01.143.1.jpg" xlink:href="020/01/143/1.jpg"/></s></p><p type="caption">

<s>Fig. </s>

<s>I<lb/>HSGT concentrico a lui, un cerchio massimo della Terra. </s>

<s><lb/>Sia P il polo, PL il meridiano principale delle Isole Fortu&shy;<lb/>nate, PM il meridiano, che passa sull'Ibero e per la Libbra, <lb/>PN quello che passa sulla foce del Gange, PO il meridiano del <lb/>sole, nel tempo a cui si riferisce l'osservazione, e AHD il <lb/>meridiano comune al Purgatorio e a Gerusalemme. </s>

<s>Si cerca <lb/>l'angolo FPO=FDE&mdash;EDO=180&deg;&mdash;EDO. </s>

<s>Ma EDO= <lb/>EL+LM+MO perci&ograve;, a risolvere il problema, conviene <lb/>cercare i tre angoli che compongono il secondo membro di <lb/>questa equazione: EL=90&deg;&mdash;LD=90&mdash;66=24. LM <lb/>potrebbe tanto farsi uguale a 12&deg; 30&prime;, quanto a 16&deg; non di&shy;<lb/>cendo nulla il Poeta che accenni, dell'Ibero, o alla sorgente o alla foce. </s>

<s>Ma osservando <lb/>anche noi con Galileo (ivi, pag. </s>

<s>135) che <emph type="italics"/>caggiono propriamente i fiumi dalle loro <lb/>fonti,<emph.end type="italics"/> crediamo di poter fare LM=12&deg;, 30&prime;, MO, dall'altra parte, &egrave; uguale a 360&deg;&mdash;OAM, <lb/>e quest'angolo OAM sarebbe l'ascensione retta di un punto M, o di una delle stelle, in <lb/>cui si configura la Libbra. </s>

<s>Qui sembra anche a noi con Galileo d'avere un indizio pi&ugrave; <lb/>certo, imperocch&egrave;, dando il Poeta l'epiteto di <emph type="italics"/>alta<emph.end type="italics"/> alla Libbra, par chiaro volere accen&shy;<lb/>nare alla lance di lei pi&ugrave; settentrionale, e di questa lance pi&ugrave; settentrionale, alla stella <lb/>pi&ugrave; cospicua. </s>

<s>Nelle <emph type="italics"/>Tavole alfonsine,<emph.end type="italics"/> delle quali si dovette anche Dante servire, si re&shy;<lb/>gistra, del bacino settentrionale della Libbra, una stella di seconda grandezza, la quale <pb xlink:href="020/01/144.jpg" pagenum="125"/>aveva allora 221&deg; di longitudine e di latitudine 8&deg; 30&prime;. </s>

<s>A questa stella par doversi riferire <lb/>il meridiano, al quale accenna il Poeta. </s>

<s>Ond'&egrave; che posto <foreign lang="greek">i</foreign>=221, <foreign lang="greek">l</foreign>=8&deg;, 30&prime;, <foreign lang="greek">e</foreign>=23&deg;, 30&prime;, <lb/>si potr&agrave; colle ordinarie formule date dai <emph type="italics"/>Formularii<emph.end type="italics"/> di Trigonometria cos.P=cos.<foreign lang="greek">*i</foreign>.cos.<foreign lang="greek">l</foreign>, <lb/>tang <foreign lang="greek">f</foreign>=(tang.<foreign lang="greek">l</foreign>)/(sen <foreign lang="greek">i</foreign>), tang.<foreign lang="greek">a</foreign>=tang.<foreign lang="greek">f</foreign> cos (<foreign lang="greek">e</foreign>+<foreign lang="greek">f</foreign>), calcolare OAM=<foreign lang="greek">a</foreign>, che, eseguiti con&shy;<lb/>venientemente i calcoli, si trover&agrave; uguale a 221&deg;, 13&prime;. </s>

<s>Perci&ograve; avremo MO=138&deg; 47&prime;, <lb/>EDO=175&deg; 17&prime;, FO=4&deg; 43&prime;. </s>

<s>Onde il sole, quando l'Angel di Dio apparse ai Poeti, <lb/><emph type="italics"/>stava<emph.end type="italics"/> cos&igrave;: era alto cio&egrave; 4&deg; 43&prime; sull'orizzonte di Gerusalemme. </s></p><p type="main">

<s>Sarebbe cos&igrave; tutto bene aggiustato, per modo che l'interpretazione astronomica, la <lb/>quale abbiamo data sulle orme di Galileo, risponderebbe a tutte le parti della descrizione <lb/>fatta nelle due sopra citate terzine dal Poeta, imperocch&egrave; PN, meridiano che passa per <lb/>la foce del Gange non sarebbe lontano da PO, meridiano del Sole, che di soli 2&deg; 47&prime;; <lb/>onde s'accomoda, anco per questa parte, l'interpretazione astronomica a quel che sog&shy;<lb/>giunge alla sua descrizione il Poeta: <emph type="italics"/>E l'onde in Gange da nona riarse.<emph.end type="italics"/></s></p><p type="main">

<s>Se non che ci si fanno qui incontro alcune difficolt&agrave;. </s>

<s>Come mai poteva dire il Poeta <lb/>che il sole vibrava i primi raggi sui colli di Gerusalemme, essendo gi&agrave; alto pi&ugrave; di quattro <lb/>gradi e mezzo sull'orizzonte? </s>

<s>Di pi&ugrave;, noi abbiamo supposto con Galileo che fosse il sole <lb/>nel punto preciso dell'Equinozio di Primavera. </s>

<s>Ma &egrave; ci&ograve; contrario all'opinione di tutti <lb/>quanti i commentatori, i quali dicono che a tempo dell'Equinozio incomincia la rappre&shy;<lb/>sentazione del Dramma, e che la scena, la quale qui si dipinge, dovette seguire almeno <lb/>tre o quattro giorni dopo, nel qual tempo si doveva il sole esser dilungato da quel punto <lb/>equinoziale, in longitudine, tre o quattro gradi. </s></p><p type="main">

<s>Le difficolt&agrave; a noi sembrano giuste, ond'&egrave; che proporremmo di riformare l'inter&shy;<lb/>pretazione galileiana al modo seguente. </s>

<s>Osservando che anche Gerusalemme &egrave; situata in <lb/>altura, e che &egrave; contrapposta, nella fantasia del Poeta, alla montagna altissima del Purga&shy;<lb/>torio, ci sembra assai ragionevole che, com'egli mise in conto una notevole depressione <lb/>dell'orizzonte per l'una, cos&igrave; qualche depressione dovesse pure mettere in conto per <lb/>l'altra. </s>

<s>Immaginiamo perci&ograve; che sulla vetta delle pi&ugrave; alte torri di Gerusalemme inco&shy;<lb/>minciasse il sole a vibrare i suoi raggi, quand'era ancora di 1&deg; 17&prime; sotto all'orizzonte <lb/>razionale. </s>

<s>In questa ipotesi, ritenute tutte le altre parti della dimostrazione, si potrebbe <lb/>dare al sole sei gradi di ascensione retta, i quali, calcolando la formula tang. </s>

<s>c=. . . <lb/>tang. </s>

<s>a cos. </s>

<s>B, si trovano corrispondere a 4&deg; 9&prime; di longitudine. </s>

<s>Cos&igrave; rimarrebbero, come <lb/>sopra, tutte le partt aggiustate, n&egrave; sarebbe a dubitar che non si potesse, con quella posizione <lb/>del sole, accordar l'effetto del riardere l'onde del Gange, perch&egrave; l'ora di nona, com&shy;<lb/>prendendo le prime sei ore avanti mezzogiorno, comprende certamente anco quella, nella <lb/>quale si trova il sole sei gradi di distanza dal meridiano, e potea perci&ograve; ben dire il Poeta <lb/>che in quella posizione del sole le onde del Gange eran riarse dall'ore di nona. </s></p><p type="main">

<s>Se l'aver concordate cos&igrave; tutte quante le parti astronomiche e geografiche della de&shy;<lb/>scrizione dantesca, ci potesse assicurare della verit&agrave; della nostra interpetrazione, avremmo <lb/>di qui un dato certo a poter inferire il mese e il giorno preciso, nel quale immagina il <lb/>Poeta essersi rappresentata la scena. </s>

<s>Poniamo, infatti, secondo la pi&ugrave; probabile e pi&ugrave; co&shy;<lb/>mune opinione, che fosse il 1300 l'anno della visione dantesca. </s>

<s>Quando l'Angel di Dio <lb/>apparse ai Poeti, abbiam veduto che il sole dovea avere 4&deg; 9&prime; in longitudine, e dovevan <lb/>perci&ograve; esser trascorsi pi&ugrave; di quattro giorni, da quello in cui entra il sole nel punto di <lb/>Primavera. </s>

<s>Se, come a noi, cos&igrave; ai tempi di Dante, fosse entrata la Primavera il d&igrave; 21 di <lb/>Marzo, &egrave; certo che la scena descritta nel XXVII del Purgatorio, si sarebbe rappresentata <lb/>la sera del d&igrave; 25 di quello stesso mese. </s>

<s>Ma per que'disordini cronologici, che hanno la <lb/>loro origine in quella parte frammentaria de'giorni, ne'quali compiesi la tropica rivolu-<pb xlink:href="020/01/145.jpg" pagenum="126"/>zione del sole, disordini non potuti evitare dagli emendamenti giuliani; nel 1300 doveva <lb/>l'Equinozio di Primavera precedere il d&igrave; 21 di Marzo di alquanti giorni. </s>

<s>Il numero poi <lb/>preciso di questi giorni si trova assai facilmente osservando che, dall'anno 325 in cui <lb/>l'Equinozio di Primavera cadde il d&igrave; 21 Marzo, al 1300, decorsero 975 giorni, ne'quali <lb/>s'aggiunsero, secondo il calendario giuliano, 243 bisestili. </s>

<s>Ma secondo la riforma nuova <lb/>gregoriana i bisestili da aggiungere dovevano essere non 975/4, ma (975X125)/516, ossia 236; <lb/>ond'&egrave; che nel 1300 l'Equinozio di Primavera precedeva il d&igrave; 21 di 7 giorni, e che &egrave; <lb/>lo stesso, avveniva quell'Equinozio il d&igrave; 14 di Marzo, e perci&ograve; la scena, che Dante l&igrave; <lb/>rappresenta, si dovrebbe precisamente riferire alla sera del d&igrave; 18 di Marzo. </s></p><p type="main">

<s><emph type="center"/><emph type="italics"/>Nota II relativa a pag. </s>

<s>82 lin. </s>

<s>37.<emph.end type="italics"/><emph.end type="center"/></s></p><p type="main">

<s>Perch&egrave; abbiano i lettori qualche saggio degli errori, in che incorse il Mollien per <lb/>ragion della lingua, citeremo il seguente passo, prima nell'ortografia originale, poi ridetto <lb/>da noi all'ortografia moderna, poi dallo stessio Mollien tradotto in francese. </s></p><p type="main">

<s>&ldquo; eglie . un pozo . il quale . a nel suo fondo unotro . di tal . grandezza e intal <lb/>modo . situato . che disotto . e dalato . non sitrova pi&ugrave; . duno dito . di grossezza dacqua . <lb/>imodo chellacqua che si posa sul fondo pesa . libbre 100 . e quella chessiposa . sopra . <lb/>della baga . pesa libbre 10000 . se cosie la baga scopiera avendo soprasse . tanto peso . <lb/>esequel peso . nolla prieme . chello sostiene . esseppure esso fussi sostenuto . perche <lb/>arebbe appassare . l'otro sopra . l'acqua . esseppure lacqua charicha . sopra . il suo . <lb/>fondo . perche non patisce passione unomo (<emph type="italics"/>menomo<emph.end type="italics"/> intende il Mollien!) passione . di <lb/>peso . stando . sopra il suo fondo . adunque sella ba sostiene lacqua la baga . toglie il <lb/>peso . dessa acqua . alfondo . del pozzo &rdquo;. </s></p><p type="main">

<s>&ldquo; Egli &egrave; un pozzo, il quale ha nel suo fondo un otro di tal grandezza e in tal <lb/>modo situato, che di sotto e da lato non si trova pi&ugrave; di un dito di grossezza d'acqua, <lb/>in modo che l'acqua che riposa sul fondo pesa libbre 100, e quella che si posa sopra <lb/>della baga pesa libbre 10,000. Se cos&igrave; &egrave; la baga scoppier&agrave; avendo sopra s&egrave; tanto peso. </s>

<s><lb/>E se quel peso non la preme, che lo sostiene? </s>

<s>E se pure esso fussi sostenuto, perch&egrave; <lb/>avrebbe a passare l'otro sopra l'acqua? </s>

<s>E se pure l'acqua carica sopra il suo fondo, per&shy;<lb/>ch&egrave; non patisce passione un uomo, passione di peso, stando sopra il suo fondo? </s>

<s>Adunque <lb/>se la baga sostiene l'acqua, la baga toglie il peso di essa acqua al fondo del pozzo. </s>

<s>&rdquo; </s></p><p type="main">

<s>&ldquo; Il y &egrave; un puits, le qual a dans sons fonds une outre, de telle grandeur et situee <lb/>di telle fac<gap/>n, que dessous et sur les cotes, ne se trouve pas plus d'un doigt d'<gap/>paisseur <lb/>d'eau. </s>

<s>l'<emph type="italics"/>eau<emph.end type="italics"/> en sorte que l'eau qui se pose sur le fond p&egrave;se 100 livres et celle qui pose <lb/>au-dessus de l'outre p&egrave;se 10,000 livres; s'il en est ainsi, l'outre celetera. </s>

<s>en ayant sur <lb/>elle <emph type="italics"/>cette<emph.end type="italics"/> un tel poids, et si ce poids ne la presse pas qu'elle soutient, et si aussi il etait <lb/>soutenou, parce que l'outre avrait a passer au-dessus de l'eau, et aussi si l'eau charge <lb/>(p&egrave;se) sur son fond, parce qu'elle ne supportarien, ne supporte qu'un moindre poids, <lb/>&egrave;tant sur son fond. </s>

<s>Donc, si l'outre soutient l'eau, l'outre &ocirc;te le poids de cette eau au <lb/>fond du puits. </s>

<s>&rdquo; (Manos. </s>

<s>A fol. </s>

<s>25 verso). </s></p><pb xlink:href="020/01/146.jpg"/><p type="main">

<s><emph type="center"/>PARTE SECONDA<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>SOMMARIO<emph.end type="center"/></s></p><p type="main">

<s>I. </s>

<s>Di Galileo Galilei e dell'indole propria della sua nuova Instaurazione scientifica. </s>

<s>&mdash; II. </s>

<s>Si giustifi&shy;<lb/>cano le cose asserite nel paragrafo precedente. </s>

<s>&mdash; III. </s>

<s>Dei benefizi che derivarono alle scienze <lb/>sperimentali dalla nuova Instaurazione galileiana. </s>

<s>&mdash; IV. </s>

<s>Renato Cartesio. </s>

<s>&mdash; V. De'primi e <lb/>principali discepoli di Galileo. </s>

<s>&mdash; VI. </s>

<s>Della grande esperienza torricelliana dell'argento vivo, e <lb/>come per lei si diffondessero, d'Italia in tutta Europa, l'amore e gli esercizi dell'arte speri&shy;<lb/>mentale. </s>

<s>&mdash; VII. </s>

<s>Di Evangelista Torricelli e di Vincenzio Viviani, e di ci&ograve; che operassero nelle <lb/>Instituzioni della sperimentale Accademia Medicea. </s>

<s>&mdash; VIII. </s>

<s>Del primo periodo della Fiorentina <lb/>Accademia del Cimento. </s>

<s>&mdash; IX. </s>

<s>Del secondo periodo della Fiorentina Accademia del Cimento. </s>

<s>&mdash; <lb/>X. </s>

<s>Delle principali Accademie private istituite in Italia a imitazione di quella del Cimento; del <lb/>felice esito dell'Istituzione Medicea, nonostante le rivalit&agrave; con gli stranieri, i dissensi fra i Socii, <lb/>le opposizioni dei Peripatetici. </s></p><p type="main">

<s><emph type="center"/>I.<emph.end type="center"/></s></p><p type="main">

<s>Egli &egrave; verissimo che tutte le cose del mondo son soggette a <lb/>invecchiare, e invecchiando andare irreparabilmente alla morte. </s>

<s>Non <lb/>vi &egrave; perci&ograve; altro rimedio per loro, che quello di tentare di ringio&shy;<lb/>vanirle e, il miglior modo a far ci&ograve;, trattandosi d'istituzioni umane, <lb/>disse argutamente il Machiavelli che consisteva nel ritirarle verso <lb/>i loro principii. </s>

<s>L'esempio che s'adduceva dianzi degli alberi tra&shy;<lb/>scorsi, i quali si ringiovaniscono recidendo i rami e talvolta lo stesso <lb/>tronco infino al piede, commenta le dottrine del Segretario fioren&shy;<lb/>tino, secondo le quali un principato, che va a dissolversi, ringio&shy;<lb/>vanisce spesso per via di una tirannide. </s></p><p type="main">

<s>Per una tirannide o per una conquista, in quella che &egrave; delle <lb/>nobilissime fra le istituzioni umane, si qualific&ograve; da noi sopra l'opera <pb xlink:href="020/01/147.jpg" pagenum="128"/>di Galileo, il quale volle scrivere in una cocca del suo vessillo queste <lb/>parole: <emph type="italics"/>Molti si pregiano di aver molte autorit&agrave; d'uomini per con&shy;<lb/>fermazione delle loro opinioni, ed io vorrei essere stato il PRIMO <lb/>e il SOLO a trovarle.<emph.end type="italics"/> Abbiamo detto in una cocca, perch&egrave; spie&shy;<lb/>gatamente in campo non sarebbero state lette tali parole dagli occhi <lb/>abbagliati de'riguardanti, se gli editori non le avessero accolte in <lb/>una nota apposta a pi&egrave; di pagina (Alb. </s>

<s>I, 440). Ma che giova l'espres&shy;<lb/>sione delle parole, se d'ogni parte si sente alitar quello spirito di <lb/>conquista proprio di un che ha fermo oramai di voler essere in <lb/>tutto il <emph type="italics"/>primo<emph.end type="italics"/> e il <emph type="italics"/>solo?<emph.end type="italics"/></s></p><p type="main">

<s>I fatti che saranno candidamente narrati, nelle varie parti di <lb/>questa Storia, mostrano que'propositi fermi coraggiosamente man&shy;<lb/>dati ad effetto, ma perch&egrave; troppo importa a noi di rappresentar fin <lb/>d'ora al giudizio dei nostri lettori l'opera galileiana sotto l'aspetto <lb/>di una conquista, e troppo ci preme di persuader fin d'ora i ritrosi <lb/>esser quello il vero aspetto, sotto cui s'appresenta la nuova instau&shy;<lb/>razione scientifica, crederemmo di dover esser notati d'imprudenza, <lb/>asserendo cose tanto lontane dalla comune opinione, senza preva&shy;<lb/>lerci di qualche discorso da servirsene come di prova. </s></p><p type="main">

<s>Bacone scrive in un luogo del suo libro <emph type="italics"/>De augmentis scien&shy;<lb/>tiarum<emph.end type="italics"/> che non parve ad Aristotile potersi bene assicurare del <lb/>Regno, <emph type="italics"/>nisi, more Ottomannorum, fratres suos omnes contruci&shy;<lb/>dasset<emph.end type="italics"/> (Lugani 1763, Part. </s>

<s>I, pag. </s>

<s>211), e son, secondo il Verulamio, <lb/>de'pi&ugrave; illustri fra que'trucidati fratelli, Pitagora, Filolao, Xenofane, <lb/>Anassagora, Parmenide, Leucippo, Democrito. </s>

<s>Aveva cos&igrave; Galileo, <lb/>della Tirannide che meditava d'&igrave;nstaurare, nello stesso Aristotile, <lb/>un esempio di tanto felice riuscita, che in ogni modo conveniva <lb/>imitare. </s></p><p type="main">

<s>Platone e Archimede son tanto lontani e tanto innocui, che <lb/>non gli turbano i sonni. </s>

<s>Ma glieli turba bene Ticone, glieli turba <lb/>il Keplero, i quali ambedue, a voler regnar solo, bisogna contru&shy;<lb/>cidare. </s>

<s>E bench&egrave; non si convenga, n&egrave; sia espediente tenere il modo <lb/>degli Ottomanni, son dirette pure a trapassare il cuore, colle loro <lb/>acute punte, e a trafigger Ticone quelle parole di Galileo, nelle <lb/>quali scrive del grande Astronomo danese, che calcol&ograve; le Tavole <lb/>Rodolfine, senza punto intender n&egrave; l'Almagesto di Tolomeo n&egrave; le <lb/>Rivoluzioni del Copernico, e che non sapeva neanco i primi ele&shy;<lb/>menti di Geometria (Alb. </s>

<s>VI, 329). Che se egli, e il suo seguace e <lb/>ammiratore Keplero, credessero di toglierli di mano lo scettro, non <lb/>gli fanno spavento que'due <emph type="italics"/>Primati:<emph.end type="italics"/> egli gli assicura d'aver tanto <pb xlink:href="020/01/148.jpg" pagenum="129"/>valore da sentirsi crescere il coraggio a seguitar contro a loro la <lb/>intrapresa conquista (ivi, pag. </s>

<s>310). </s></p><p type="main">

<s>Ma il Keplero, per verit&agrave;, era uno di quei giganti da non ce&shy;<lb/>dere al primo colpo, per cui, meglio che il ferro tagliente e nudo, <lb/>conobbe Galileo che avrebbe servito bene il veleno confettato con <lb/>arte per toglierli l'amaro. </s>

<s>Una fra le tante di cos&igrave; fatte confezioni <lb/><figure id="id.020.01.148.1.jpg" xlink:href="020/01/148/1.jpg"/><lb/>&egrave; quella che ha nell'ultimo Dialogo dei Due Massimi Sistemi, dove <lb/>l'influenze della Luna sulla marea, sagacemente indovinate dal&shy;<lb/>l'Alemanno, <emph type="italics"/>ingegno libero e acuto,<emph.end type="italics"/> sono annoverate fra le altre <lb/><emph type="italics"/>fanciullezze<emph.end type="italics"/> (Alb. </s>

<s>I, 499). E perch&egrave;, anco le confezioni pi&ugrave; avvele&shy;<lb/>nate, quello era tale stomaco da digerirle, Galileo si risolv&egrave; di esi&shy;<lb/>liar quell'ombra paurosa da'suoi confini, dichiarando di non aver <pb xlink:href="020/01/149.jpg" pagenum="130"/>nulla a che rivedere con lui. </s>

<s>Che se talvolta s'incontra in qualche <lb/>concetto simile, afferma esser ci&ograve; tanto avvenuto di rado, da non <lb/>si verificare di uno in cento de'suoi pensieri (Alb. </s>

<s>VII, 56). </s></p><p type="main">

<s>Quell'esilio, dall'altra parte, &egrave; decretato con editto irrevoca&shy;<lb/>bile. </s>

<s>L'Autore del Commentario sulla stella di Marte, dimostra co&shy;<lb/>me cosa di fatto, che le orbite dei pianeti sono ellittiche. </s>

<s>Ma Ga&shy;<lb/>lileo non si rimuove dalla platonica perfezione delle orbite circolari. </s>

<s><lb/>L'Autore dei Paralipomeni a Vitellione, dimostra ad evidenza, per, <lb/>ci&ograve; che si sperimenta nella camera oscura, che le immagini si di&shy;<lb/>pingono rovesciate sulla retina, ma Galileo persiste nelle viete gale&shy;<lb/>niche dottrine, a seconda delle quali il luogo, dove si rappresentan <lb/>diritte le immagini, &egrave; il centro della pupilla, ossia il cristallino. </s>

<s><lb/>L'Autore della <emph type="italics"/>Diottrica<emph.end type="italics"/> aveva divisate le leggi del rifrangersi i <lb/>raggi luminosi nelle lenti concave e nelle convesse, e s'era, per <lb/>teoria, incontrato nella scoperta del canocchiale astronomico, ma <lb/>Galileo dice al Tarde che quel Trattatello &egrave; cos&igrave; oscuro, da non <lb/>restarne sodisfatto nemmeno l'Autore stesso. </s></p><p type="main">

<s>Che il Kepler non tutto abbia dimostrato e concluso con chia&shy;<lb/>rezza, potrebbe anco esser vero. </s>

<s>Ma vero certamente non &egrave; quel che <lb/>Galileo stesso soggiungeva non aver nel 1614, quand'ebbe quel col&shy;<lb/>loquio col Tarde, nessuno ancora scritto della teoria del canocchiale. </s>

<s><lb/>Ne aveva gi&agrave; scritto il De Dominis, il Trattato del quale gli fu spe&shy;<lb/>dito a Firenze dal Sagredo (Alb. </s>

<s>Supplem. </s>

<s>pag. </s>

<s>58), e ne aveva in <lb/>certo modo scritto anco il Maurolico, bench&egrave; non trattasse propria&shy;<lb/>mente delle lenti composte nel canocchiale, ma della diottrica delle <lb/>lenti separate, in quel libretto postumo che vide, nel 1611, la luce <lb/>insiem con quello del De Dominis e del Keplero. </s></p><p type="main">

<s>L'esilio dunque, a quel che pare, &egrave; bandito contro di tutti <lb/>senza eccezione, e basta legger le Opere di Galileo per vederne <lb/>eseguito il decreto. </s>

<s>Egli non ha, e non riconosce maestro: nessuno <lb/>dee venirgli innanzi a dir che egli abbia scoperto qualche cosa di <lb/>nuovo: tutte le nuove scoperte vuole averle fatte da s&egrave;, il primo <lb/>e il solo. </s>

<s>Gli si cita dal Sarsi il Cardano e il Telesio: quel che <lb/>abbiano scritto, risponde, il Cardano e il Telesio, io non l'ho veduto <lb/>(Alb. </s>

<s>IV, 178). Non ha veduto o fa vista di non aver veduto il Tar&shy;<lb/>taglia, che fu de'primi a notare gli errori meccanici di Aristotile, <lb/>e a porre i fondamenti alla teoria e alla pratica de'proietti, non <lb/>ha veduto il Fracastoro, che al corso obliquo del sole applicava il <lb/>teorema della composizione dei moti. </s></p><p type="main">

<s>Lorenzo Crasso fra gli Elogi degli uomini letterati raccolse an-<pb xlink:href="020/01/150.jpg" pagenum="131"/>che quello di Galileo, e ce lo rappresenta timido in dar fuori i suoi <lb/>sentimenti circa la Filosofia Naturale, i quali vuol che egli cavasse <lb/>da Celio Calcagnini e dal Patrizio. </s>

<s>Michelangiolo Ricci, l'amico e <lb/>il Discepolo prediletto del Torricelli, e il consultore dell'Accademia <lb/>del Cimento, in una lettera al principe Leopoldo dei Medici, rim&shy;<lb/>provera l'Autore di quegli Elogi per aver taciuto di annoverare <lb/>fra'maestri di Galileo il Benedetti, <emph type="italics"/>che gli apr&igrave; la strada pi&ugrave; che <lb/>ogni altro e forse fu solo a lui scorta nel suo filosofare, come avr&agrave; <lb/>ben notato V. A. paragonando i concetti dell'uno e dell'altro che <lb/>sono tanto conformi.<emph.end type="italics"/> (MSS. Gal. </s>

<s>Cim. </s>

<s>XVIII, 359). </s></p><p type="main">

<s>I nostri lettori, i quali hanno passato in esame con noi, di so&shy;<lb/>pra, il libro delle Speculazioni del Fisico veneziano, sentono la ve&shy;<lb/>rit&agrave; del giudizio del Ricci, e dall'altra parte chi collaziona le parole <lb/>scritte da Galileo, in sul principio della sua Lettera al Mazzoni <lb/>(Alb. </s>

<s>II, 1), con quel che il Mazzoni stesso dice nel Cap. </s>

<s>XVIII, <lb/>de'<emph type="italics"/>Preludi alla Filosofia di Platone e di Aristotile,<emph.end type="italics"/> da pag. </s>

<s>187-95 <lb/>dell'edizion di Venezia 1597; rileva chiaramente che in Pisa i due <lb/>professori conferivano insieme sulle Questioni Meccaniche del Be&shy;<lb/>nedetti, intorno alle quali il giovane Galileo s'esercit&ograve; tanto studio&shy;<lb/>samente, che ne compose quel Trattato informe <emph type="italics"/>De motu<emph.end type="italics"/> dato ora <lb/>che &egrave; poco alla luce da pag. </s>

<s>251-419 del volume primo dell'edizion <lb/>Nazionale (Firenze 1890). Eppure, bench&egrave; Michelangiolo Ricci, e, <lb/>che pi&ugrave; conta, i fatti attestino che Galileo bevve cos&igrave; largamente al <lb/>libro delle Speculazioni, non &egrave; possibile il trovare in nessuna delle <lb/>Scritture galileiane, o edite o inedite o pubbliche o familiari, ricor&shy;<lb/>dato mai o almeno accennato al nome di Giovan Battista Benedetti. </s></p><p type="main">

<s>Solenne maestro in Idrostatica, poco prima che Galileo dasse <lb/>opera alle <emph type="italics"/>Galleggianti,<emph.end type="italics"/> era dalla lontana Bruges apparito Simeone <lb/>Stevino, un'altra di quelle ombre paurose che, a voler regnar solo, <lb/>o bisognava contrucidare, o in qualche modo esiliare dai proprii <lb/>confini. </s>

<s>Or avvenne che codesto bandito straniero, allacciato quasi <lb/>alla coda di un Discorso accademico letto in Roma da Giovanni <lb/>Bardi, comparisse al cospetto di Galileo. </s>

<s>Quel Discorso &egrave; inti&shy;<lb/>tolato <emph type="italics"/>Eorum quae vehuntur in aquis Experimenta<emph.end type="italics"/> (Targioni, Ag&shy;<lb/>grandim. </s>

<s>T. II, P. I, pag. </s>

<s>2) e si termina dall'Autore coll'aggiungervi <lb/>quel curioso paradosso, dimostrato dallo Stevino ne'suoi Elementi <lb/>d'Idrostatica, di un vaso cilindrico pieno d'acqua che, sollevato in <lb/>alto sotto un cilindro solido fisso nel muro, in modo che entri dentro <lb/>a quello di sotto, scacciandone via l'acqua, da rimanerne quasi vuoto; <lb/>pesa nonostante sulla stadera, allo stesso modo che quando era pieno. <pb xlink:href="020/01/151.jpg" pagenum="132"/>&mdash; Quale sciocchezza sarebbe a lasciar questa perla cos&igrave; preziosa ad&shy;<lb/>addosso a questo straniero? </s>

<s>Facciamola nostra, pens&ograve; Galileo, e poi <lb/>rimandiamolo addietro. </s>

<s>&mdash; Chi legge la Lettera a Tolomeo Nozzolini <lb/>(Alb. </s>

<s>XII, 112) ritrova questo appropriamento fatto con s&igrave; maravi&shy;<lb/>gliosa destrezza, che la poca facondia di qualunque oratore baste&shy;<lb/>rebbe a rimandare il colpevole assoluto. </s>

<s>N&egrave; minor destrezza, per <lb/>non moltiplicare in esempi, us&ograve; nel III Dialogo de'Due Massimi Si&shy;<lb/>stemi, in appropriarsi l'osservazione dei varii dilatamenti della pu&shy;<lb/>pilla, al variar dell'intensit&agrave; luminosa. (Alb. </s>

<s>I, 394). </s></p><p type="main">

<s>In un altro Autore cos&igrave; fatte destrezze di mano passerebbero <lb/>inosservate, ma in Galileo rivelano l'esecuzione di un tenace pro&shy;<lb/>posito, qual era di voler essere in qualunque modo o di apparire <lb/>in tutto il primo e il solo. </s>

<s>Da questo stesso genio veniva frugato <lb/>a moltissime occasioni, quando si trattava di rivendicare scoperte, <lb/>che sarebbero state per giustizia appartenute agli odiati molesti <lb/>competitori. </s>

<s>Gli d&agrave; nuova il Sagredo di aver veduto in Padova, ap&shy;<lb/>presso il Santorio, uno strumento da misurar col compasso i gradi <lb/>del calore e del freddo. </s>

<s>Galileo risponde che quello strumento era <lb/>di sua propria invenzione. </s>

<s>Ma in effetto, col pretesto di rivendicare <lb/>a s&egrave; l'esperienza, intendeva usurparsi l'applicazione della esperienza <lb/>stessa, nella quale sola consisteva il merito dell'invenzione del ter&shy;<lb/>mometro. </s>

<s>Che anzi, sebbene egli dice di aver fatto quella tale espe&shy;<lb/>rienza in Padova nel 1606 (Alb. </s>

<s>VI), 313) gli si pu&ograve; rispondere che, <lb/>fin dal 1550, l'aveva pubblicata il Porta nel II Libro fra'quattro <lb/>della <emph type="italics"/>Magia,<emph.end type="italics"/> e nel 1601, nel III Libro degli Spiritali l'aveva ar&shy;<lb/>gutamente illustrata, applicandola alla soluzione di un importantis&shy;<lb/>simo problema, qual'&egrave; quello di trovare il volume, a cui pu&ograve;, per <lb/>la massima dilatazione, ridursi l'aria. </s>

<s>La teoria poi dello strumento <lb/>fondata sul principio materiale degli egnicoli, di che tanto rimase <lb/>sodisfatto il Sagredo, a una lettera di Galileo, l'avea data gi&agrave; il Be&shy;<lb/>nedetti con pi&ugrave; squisito giudizio. </s></p><p type="main">

<s>E intorno alla scoperta delle macchie solari, che fiera guerra <lb/>non muove questo ardito conquistatore! E perch&egrave;? </s>

<s>Se si riguarda <lb/>la materiale e occasionale osservazione del fatto, non ci &egrave; dubbio <lb/>che il Fabricio, e tutti coloro che, eccitati dall'<emph type="italics"/>Avviso sidereo,<emph.end type="italics"/> eb&shy;<lb/>bero il coraggio di farsi bruciare gli occhi, osservando direttamente <lb/>il sole, o si prevalsero dell'ingegno di riguardarlo per proiezione; <lb/>precedettero lo Scheiner e Galileo. </s>

<s>Se si ha riguardo a chi primo <lb/>si rivolse all'osservazione del fatto, con vero intendimento scienti&shy;<lb/>fico, i documenti attestano che lo Scheiner preced&egrave; Galileo Se si <pb xlink:href="020/01/152.jpg" pagenum="133"/>attende poi a chi primo filosof&ograve; sulla natura del fatto, e investig&ograve; <lb/>la fisica costituzione del sole nelle sue macchie, nessuno pu&ograve; venire <lb/>alle prove con Galileo. </s>

<s>Ora &egrave; chiaro che tutto il merito scientifico <lb/>consisteva qui, e di ci&ograve; solo poteva meritamente gloriarsi e con&shy;<lb/>tentarsi l'Autore delle Lettere velseriane. </s>

<s>Eppure egli sputa fuoco <lb/>e veleno contro il Gesuita tedesco, perch&egrave;, anche nell'osservazione <lb/>materiale del fatto, anche in averne conosciuta e apprezzata l'im&shy;<lb/>portanza scientifica, non vuol competitori, vuole in tutto e per tutto <lb/>essere il primo ed il solo. </s>

<s>E da quale altro genio era mosso, se <lb/>non da questo, quando s'indusse a tacer della cooperazione, che <lb/>ebbe il Sarpi in quelle osservazioni celesti, di cui volle apparire <lb/>al mondo primo e unico Messaggero? </s></p><p type="main">

<s>Il canocchiale, che andava oramai per le mani di molti signori, <lb/>e si sapeva per fatto certo da tutti esser venuto d'Olanda, non era, <lb/>com'altri ritrovati, di cos&igrave; facile conquista. </s>

<s>Perci&ograve; qui procede Ga&shy;<lb/>lileo con pi&ugrave; liberalit&agrave;, che nell'affar delle macchie solari. </s>

<s>Renunzia <lb/>alla fortuita materialit&agrave; dell'invenzione, e si contenta di appropriarsi <lb/>la soluzione di un problema diottrico, gi&agrave; formulato; soluzione a <lb/>che egli dice esser riuscito per opera di solo discorso, e in che egli <lb/>afferma consistere tutto il vero merito di quella stessa invenzione. <lb/>(Alb. </s>

<s>IV, 207, 8). Altri prima di noi ha notato l'incongruenza, che <lb/>&egrave; fra questa storia del ritrovamento del canocchiale data nel Sag&shy;<lb/>giatore, e in altre varie Scritture di Galileo, e ci&ograve; sarebbe segno <lb/>che quelle narrazioni non avevano i fondamenti sinceri e confer&shy;<lb/>mati nel vero. </s>

<s>Ma quanto vana pretensione fosse quella sua d'aver <lb/>ritrovata la composizione dell'ammirabile strumento per via di di&shy;<lb/>scorso, si parr&agrave; dai fatti che a suo luogo si narreranno. </s>

<s>Giova in&shy;<lb/>tanto osservare, a proposito di questi diottrici discorsi fatti nel <lb/>Nunzio Sidereo e nel Saggiatore, le variet&agrave; e anzi le contradizioni <lb/>che si rilevano apertamente collazionando l'uno coll'altro. </s>

<s>L&agrave;, nel <lb/>Nunzio, aveva riconosciuto il modo e la ragion dell'operare del ca&shy;<lb/>nocchiale, nel condensamento de'raggi attraverso al diafano delle <lb/>lenti (Alb. </s>

<s>III, 62); qui, nel Saggiatore, confuta quelle medesime <lb/>dottrine, contradicendo a se stesso, nell'atto che vuol contradire al <lb/>Sarsi. </s>

<s>Notabile di pi&ugrave; che in questa strana argomentazione di Ga&shy;<lb/>lileo contro il suo avversario, si trova aggirato in un altra contra&shy;<lb/>dizione, la quale consiste in ammetter che i raggi <emph type="italics"/>entrino<emph.end type="italics"/> nelle <lb/>pupille, mentre sempre, e in questa stessa scrittura del Saggiatore, <lb/>dice che <emph type="italics"/>escono,<emph.end type="italics"/> professando le platoniche teorie dell'estramissione. <lb/>(Alb. </s>

<s>IV, 203). </s></p><pb xlink:href="020/01/153.jpg" pagenum="134"/><p type="main">

<s>Cos&igrave; fatte contradizioni hanno in tutti gli Autori origine dal <lb/>progredir della mente, e piuttosto che contradizioni si dovrebbero <lb/>dire e sono ritrattazioni. </s>

<s>Ma Galileo, se si corregge, lo fa con tale <lb/>studioso accorgimento, da non fare apparir che egli abbia errato, <lb/>specialmente se da qualcuno gli &egrave; stato suggerito di corregger l'er&shy;<lb/>rore. </s>

<s>Di ci&ograve; pure &egrave; bene sodisfare ai nostri lettori di qualche esempio. </s></p><p type="main">

<s>Nel Nunzio Sidereo dice che il piccolo corpo globoso delle stelle, <lb/>per via dell'irradiazione, s'accresce di grandezza nell'occhio, co&shy;<lb/>sicch&egrave; il canocchiale radendo all'astro il capellizio, &egrave; cagione di <lb/>rappresentarlo pi&ugrave; terminato s&igrave; nel suo contorno, ma pur alquanto <lb/>rimpiccolito. </s>

<s>Dall'esser soggetto per&ograve; a tale accrescimento e decre&shy;<lb/>mento di grandezza apparente esclude la Luna (Alb. </s>

<s>III, 74). Un <lb/>anno dopo, scrivendo al Grienberger, dice che <emph type="italics"/>la Luna s'incorona <lb/>ella ancora come ogni altro corpo luminoso de'suoi raggi<emph.end type="italics"/> (ivi, pa&shy;<lb/>gina 65), ma, soggiungendo che il Telescopio <emph type="italics"/>toglie in gran parte <lb/>la detta irradiazione col portarci la specie della luna molto vicina<emph.end type="italics"/><lb/>(ivi, pag. </s>

<s>168), d&agrave; a diveder che egli persiste tuttavia in credere la <lb/>irradiazione risieder nell'astro e no nell'occhio. </s>

<s>Nel Saggiatore, che <lb/>vuol dire nel 1623, dodici anni dopo avere scritta la citata lettera <lb/>al Grienbergero, l'Autore ha mutato opinione anco rispetto a questa <lb/>seconda parte della sua dottrina. </s>

<s>Afferma ivi, senz'altro, che <emph type="italics"/>quel <lb/>fulgore ascitizio delle stelle non &egrave; realmente intorno alle stelle ma <lb/>&egrave; nel nostro occhio<emph.end type="italics"/> (Alb. </s>

<s>IV, 194) e ci&ograve; torna solennemente a con&shy;<lb/>fermare nel III Dialogo dei Massimi Sistemi, dove descrivendo la <lb/>corda tesa ad uso di micrometro, dice che essa, <emph type="italics"/>nel coprire il nudo <lb/>corpicello della stella, leva via i capelli che non son suoi ma del <lb/>nostro occhio<emph.end type="italics"/> (Alb. </s>

<s>I, 393). Ora tutti questi che paion frutti germo&shy;<lb/>gliati spontaneamente, sono invece il portato di un ramo nuovo ri&shy;<lb/>messo in luogo del vecchio, reciso dalla forbice del Keplero, il quale <lb/>aveva, nella Dissertazione sul Nunzio Sidereo, richiamato sopra la <lb/>sua <emph type="italics"/>Ottica<emph.end type="italics"/> l'attenzione di Galileo, e aveva concluso contro di lui <lb/>&ldquo; Neque perspicillum in terra adimit aliquid stellis in coelo, sed <lb/>adimit aliquid lucis retiformi, quantum eius redundat &rdquo; (Alb. </s>

<s>V, 425). </s></p><p type="main">

<s>Uno de'pi&ugrave; curiosi problemi, proposti all'Ottica astronomica, <lb/>era quello del Sole ellittico sull'orizzonte. </s>

<s>Ticone, il Keplero, e pi&ugrave; <lb/>particolarmente lo Scheiner, che ne scrisse un libro apposito e ne <lb/>offer&igrave; una copia a Galileo (Campori, Carteg. </s>

<s>galil. </s>

<s>Modena 1881, <lb/>pag. </s>

<s>86), avevano tentato in qualche modo di risolvere il problema. </s>

<s><lb/>Ma l'Autore del Saggiatore, che non aveva potuto ancora perdonare <lb/>al gesuita tedesco l'avere osato d'ingerirsi del suo Regno, in ri-<pb xlink:href="020/01/154.jpg" pagenum="135"/>compensa del dono ricevuto, deride amaramente l'Autore, per avere <lb/>scritto del sole ellittico, come di problema astruso, un intiero trat&shy;<lb/>tato, <emph type="italics"/>ancorch&egrave; tutto il mistero non ricerchi maggior profondit&agrave; di <lb/>dottrina che l'intender per qual ragione un cerchio veduto in <lb/>maest&agrave; ci paia rotondo, ma guardato in iscorcio ci apparisce ovato<emph.end type="italics"/><lb/>(Alb. </s>

<s>IV, 344). Ma come c'entra il cerchio se si tratta del sole che <lb/>&egrave; una sfera? </s>

<s>La cosa dovette sembrare allo stesso Autore assai <lb/>strana, e tornandoci sopra a speculare, s'avvide che il problema <lb/>non era di cos&igrave; facile soluzione, come l'aveva prima creduto, e <lb/>perci&ograve; nelle <emph type="italics"/>Operazioni astronomiche,<emph.end type="italics"/> correggendo colle rifrazioni <lb/>di Ticone e del Keplero le riflessioni speculari dello Scheiner, riusc&igrave; <lb/>finalmente a incontrarsi nel vero, bench&egrave; seguitasse a esprimersi <lb/>ancora sotto forma di dubbio. </s>

<s>Se il sole si mostra bislungo, credo <lb/>io veramente accadere, egli scrive, <emph type="italics"/>perch&egrave;, merc&egrave; dei vapori bassi, <lb/>l'inferior parte del disco solare viene pi&ugrave; inalzata che la superiore, <lb/>restando l'altra dimensione, cio&egrave; la lunghezza, inalterata<emph.end type="italics"/> (Alb. </s>

<s>V, <lb/>383, 84). Anco questo per&ograve; appar sotto tutt'altro aspetto che di una <lb/>ritrattazione, e anzi &egrave; notabile lo studio posto dall'Autore in cansar <lb/>ogni pi&ugrave; piccolo accenno, per cui potessero risovvenirsi i lettori e <lb/>accorgersi di un errore trascorso. </s></p><p type="main">

<s>La libidine del regnare non conosce ritegni: si trucidano gli <lb/>stranieri e i fratelli, si spogliano delle sostanze i nemici paurosi, e <lb/>gli amici pi&ugrave; confidenti. </s>

<s>Fra questi pi&ugrave; confidenti amici di Galileo <lb/>era Bonaventura Cavalieri, il quale aveva appresi i principii dimo&shy;<lb/>strativi delle leggi del moto dalla meditazione dei Dialoghi de'Due <lb/>Massimi Sistemi. </s>

<s>Or avendo, in un suo libro, a trattar delle sezioni <lb/>del cono, applicando quei meccanici principii, si trov&ograve;, quasi senz'av&shy;<lb/>vedersene, condotta in mano la dimostrazione che i proietti, non <lb/>avuto riguardo alle resistenze, descrivevano nel libero spazio vuoto <lb/>una parabola. </s>

<s>Nel mentre che il libro faceva i primi passi per <lb/>uscire alla luce, il modesto Autore dello <emph type="italics"/>Specchio Ustorio<emph.end type="italics"/> d&agrave; avviso <lb/>all'amato Maestro della bella e nuova proposizione dimostrata, spe&shy;<lb/>rando se ne dovesse assai compiacere. </s>

<s>Ma qual divenne l'umile <lb/>fraticello, quando Cesare Marsili ebbe a leggergli quella lettera di <lb/>Galileo, piena di rimproveri sdegnosi saettati in mezzo all'imper&shy;<lb/>versare pi&ugrave; tempestoso dell'ira? </s>

<s>E perch&egrave; mai tanto sdegno? </s>

<s>Perch&egrave; <lb/>colui che in tutto voleva essere il primo e il solo, pretendeva che <lb/>il teorema delle traiettorie paraboliche fosse suo. </s>

<s>Il fatto e il modo <lb/>di una tale usurpazione, forniranno un soggetto de'pi&ugrave; nuovi e <lb/>importanti alla nostra storia, ma intanto, perch&egrave; in brevi tratti <pb xlink:href="020/01/155.jpg" pagenum="136"/>di penna si concluda, ecco l'esempio di un'altra usurpazione pi&ugrave; <lb/>manifesta di quella e pi&ugrave; violenta. </s></p><p type="main">

<s>Il d&igrave; 19 Dicembre 1634 il Cavalieri scriveva una lettera a Ga&shy;<lb/>lileo, nella quale gli domandava il suo giudizio intorno alla <emph type="italics"/>Geo&shy;<lb/>metria degli indivisibili,<emph.end type="italics"/> non ancora finita di stampare, poi soggiunge <lb/>le seguenti parole: &ldquo; Scrivo in fretta, perci&ograve; mi scusi della negli&shy;<lb/>genza dello scrivere, e ci&ograve; per avere io voluto trascrivere un pen&shy;<lb/>siero intorno alla definizione V. del Quinto d'Euclide, quale le <lb/>mando per sentirne il suo parere.... Se le paresse cosa buona, <lb/>averei pensiero di metterla nel fine della mia Geometria &rdquo; (Campori, <lb/>ivi, pag. </s>

<s>423). Al sagace lettore quel Pensiero del Cavalieri parve <lb/>anzi tanto buono, che disegn&ograve; di farlo suo, e perci&ograve; distolse, con <lb/>lusinghiera persuasione, l'Autore dal pubblicarlo. </s>

<s>Ci&ograve; si rileva da <lb/>un altra lettera dello stesso Cavalieri, il quale troppo facilmente <lb/>lasciatosi vincere alle lusinghe, proponeva d'aspettare a pubblicar <lb/>ci&ograve; che intendeva di metter per appendice alla sua Geometria, <emph type="italics"/>pi&ugrave; <lb/>opportuna occasione<emph.end type="italics"/> (ivi, pag. </s>

<s>429). Ma il fatto si &egrave; che, invece di <lb/>andar quell'appendice a incoronar la Geometria degli indivisibili, <lb/>and&ograve; ad aggiungersi ai quattro Dialoghi delle Due Nuove Scienze. </s>

<s><lb/>Ii Pensiero trascritto e mandato da Bologna a Galileo, il giorno, il <lb/>mese e l'anno suddetto, non &egrave; smarrito. </s>

<s>Quando noi lo sottopor&shy;<lb/>remo all'esame de'nostri lettori, vedranno che, non la materia sola, <lb/>ma la mossa stessa e gli stessi andamenti del dialogo galileiano son <lb/>ritratti da quel <emph type="italics"/>Pensiero<emph.end type="italics"/> scritto dal Cavalieri. </s></p><p type="main">

<s><emph type="center"/>II.<emph.end type="center"/></s></p><p type="main">

<s>Bench&egrave; non la fantasia o il passionato giudizio ma i fatti ci <lb/>abbiano rappresentato Galileo, come Aristotile si rappresent&ograve; al Ve&shy;<lb/>rulamio, sotto l'aspetto di un conquistatore, che stabilisca il suo <lb/>regno a somiglianza de'pi&ugrave; scaltri e coraggiosi tiranni; prevediamo, <lb/>nonostante, che molti resteranno scandalizzati alla verit&agrave;, che ha <lb/>sapore di amaro. </s>

<s>Anzi siam di ci&ograve; pi&ugrave; che certi, tanto vanno a ri&shy;<lb/>troso della corrente opinione quelle nostre storiche conclusioni. </s>

<s>E <lb/>come infatti si possono conciliare insieme i titoli di tiranno e di <lb/>divino? </s>

<s>Se nei conquistatori politici gli concili&ograve; spesso l'adulazione <lb/>o il timore, non hanno simili passioni alcun effetto nel caso nostro, <pb xlink:href="020/01/156.jpg" pagenum="137"/>in cui nulla s'ha da perdere o da sperare. </s>

<s>Non si pu&ograve; altro dir <lb/>dunque se non che questa invalsa e corrente opinione, che contra&shy;<lb/>dice ai fatti storici, abbia tolta la libera serenit&agrave; dei giudiz&icirc;. </s></p><p type="main">

<s>Che sia veramente cos&igrave;, ne possiamo vedere gli esempi in due <lb/>dei pi&ugrave; grandi uomini, che, tra il finire del secolo passato e il co&shy;<lb/>minciare del nostro, fiorirono fra i cultori degli studi galileiani. </s>

<s>Da <lb/>che il Lagrangia afferm&ograve; e il Venturi diffuse la sentenza, s'&egrave; ripe&shy;<lb/>tuto e si ripete da tutti che Galileo fu primo a introdurre nella <lb/>Meccanica il principio della composizione delle forze e delle velocit&agrave; <lb/>virtuali. </s>

<s>Ora &egrave; un fatto che, fra tutte le sentenze, nessun altra &egrave; <lb/>pi&ugrave; aliena dal vero di questa. </s></p><p type="main">

<s>Qual documento che attesti aver Galileo veramente professato <lb/>il principio, che la resultante di due forze &egrave; determinata in inten&shy;<lb/>sit&agrave; e in direzione dalla diagonale, si cita il teorema II della quarta <lb/>Giornata delle Due Nuove. </s>

<s>Scienze. </s>

<s>Ma il Cartesio, nel tempo stesso, <lb/>aveva applicato quel teorema alla luce, come si pu&ograve; veder dal &sect; 2&deg; <lb/>del secondo capitolo della <emph type="italics"/>Diottrica<emph.end type="italics"/> pubblicata in francese nel 1637. <lb/>Ed &egrave; a notar che l'Autore, il quale, come altrove, anco qui insiste <lb/>sulle orme del Keplero, ripete i processi dimostrativi della propo&shy;<lb/>sizione XIX dei <emph type="italics"/>Paralipomeni a Vitellione,<emph.end type="italics"/> dove il moto obliquo del <lb/>raggio luminoso e incidente sopra lo specchio si decompone in due, <lb/>uno perpendicolare e l'altro parallelo alla superficie del medesimo <lb/>specchio (Francof. </s>

<s>1604, pag. </s>

<s>15). Anzi quell'ingenuo e schietto ca&shy;<lb/>rattere del grande Alemanno non tace che l'applicazione del teo&shy;<lb/>rema meccanico ai moti della luce risale su fino ad Alhazen e a <lb/>Vitellione, de'quali autori scrive queste parole: &ldquo; Et addunt subtile <lb/>nescio quid motum lucis oblique incidentis componi ex motu per&shy;<lb/>pendiculari et motu parallelo ad densi superficiem &rdquo; (ibi, pag. </s>

<s>84). </s></p><p type="main">

<s>Galileo propriamente non fece altro che tentar del teorema una <lb/>dimostrazione, la quale &egrave; fondata sopra l'equivoco tra <emph type="italics"/>potenza di&shy;<lb/>namica<emph.end type="italics"/> e <emph type="italics"/>potenza numerica.<emph.end type="italics"/> Preso a quell'equivoco rimase a prin&shy;<lb/>cipio anche il Mersenno, come si par dalla proposizione XXII della <lb/>sua <emph type="italics"/>Meccanica<emph.end type="italics"/> (Parisiis 1644, pag. </s>

<s>81) e se ne accorse o ne fu fatto <lb/>accorto appena stampato il libro. </s>

<s>Perci&ograve;, nella Prefazione innume&shy;<lb/>rata, fra le altre cose di che si ricrede, ci &egrave; anche quella proposi&shy;<lb/>zione, della quale, dopo aver detto che <emph type="italics"/>est ex mente Galilaei pag. </s>

<s>250 <lb/>Dialogorum,<emph.end type="italics"/> immediatamente soggiunge: &ldquo; quod tamen minime <lb/>verum esse videtur. </s>

<s>&rdquo; Non falso il teorema, falso il principio dimo&shy;<lb/>strativo, che cio&egrave; la potenza della resultante sia uguale alla somma <lb/>delle potenze o de'quadrati delle due componenti: anzi il teorema <pb xlink:href="020/01/157.jpg" pagenum="138"/>stesso, secondo i principii galileiani, non sarebbe vero, se non nel <lb/>caso delle forze ortogonali. </s>

<s>Le perniciose conseguenze di cos&igrave; fatte <lb/>dottrine daranno alla nostra storia della Meccanica soggetto di lungo <lb/>e importante discorso, ma intanto passiamo a veder quel che si dice <lb/>di Galileo, rispetto alle velocit&agrave; virtuali. </s></p><p type="main">

<s>Ch'ei veramente professasse questo principio &egrave; chiaro da quel <lb/>che nella <emph type="italics"/>Scienza Meccanica<emph.end type="italics"/> si legge (Alb. </s>

<s>XI, 93), e da quel che <lb/>dice altrove (Alb. </s>

<s>XIII, 176) raccogliesi che, nel trattar delle Mec&shy;<lb/>caniche, quello stesso principio non era nuovo agli autori. </s>

<s>Guidu&shy;<lb/>baldo Del Monte infatti, bench&egrave; non sapesse formularlo e renderlo <lb/>generale, pur ne fece in qualche modo l'applicazione nella proposi&shy;<lb/>zione XIII <emph type="italics"/>De trochlea,<emph.end type="italics"/> e nel corollario I della prima proposizione <emph type="italics"/>De <lb/>axe in peritochio,<emph.end type="italics"/> come in altre parti del suo <emph type="italics"/>Machenicorum liber.<emph.end type="italics"/></s></p><p type="main">

<s>Galileo poi &egrave; verissimo che, di quel princip&igrave;o delle velocit&agrave; <lb/>virtuali, ne fece due insigni applicazioni, distanti cos&igrave; di tempo fra <lb/>loro, da segnare i due termini estremi della gloriosa scientifica sua <lb/>carriera: l'una all'equilibrio dei liquidi nei vasi comunicanti, l'altra <lb/>alla teoria dei piani inclinati. </s>

<s>Non sapremmo dir propriamente se <lb/>l'Autore del Discorso intorno ai galleggianti presentisse le difficolt&agrave; <lb/>promosse contro la sua dimostrazione, la quale in verit&agrave; non con&shy;<lb/>clude, se non nel caso che i due vasi comunicanti sien cilindrici <lb/>e verticali, e ambedue di ugual calibro. </s>

<s>Quel che possiamo per&ograve; <lb/>asserire per cosa certa &egrave; che, non appena ebbe trattata, in quell'Ag&shy;<lb/>giunta da farsi alla stampa leydese del III Dialogo, la nuova teoria <lb/>del piano inclinato col principio delle velocit&agrave; virtuali, che cominci&ograve; <lb/>a scrupoleggiare intorno alla verit&agrave; di quello stesso principio. </s></p><p type="main">

<s>Si fonda questa nostra certezza sull'esame di quelle carte in&shy;<lb/>formi e disordinate, su cui la mano dell'Autore e del Torricelli <lb/>divisarono la riforma, in gran parte radicale, da farsi al Trattato <lb/>delle Due Nuove Scienze. </s>

<s>Si rileva da queste carte che uno dei <lb/>principii da riformare era quello appunto delle velocit&agrave; virtuali, <lb/>avendo qualche durezza nell'apprendersi come mai <emph type="italics"/>quella mag&shy;<lb/>gioranza che non &egrave;, ma ancora ha da essere, possa produrre un <lb/>effetto presente<emph.end type="italics"/> (MSS. Gal. </s>

<s>Div. </s>

<s>II. P. V. T. IV. c. </s>

<s>29). S'accenna evi&shy;<lb/>dentemente, con s&igrave; fatte parole, alla teoria della libbra di braccia <lb/>disuguali; teoria applicata da Galileo alle braccia di disugual ca&shy;<lb/>pacit&agrave; di un sifone pieno di liquido: ma che il dubbio si estendesse <lb/>altres&igrave; alla nuova teoria del piano inclinato, si par da quell'altra <lb/>nota che dice: <emph type="italics"/>pensare se &egrave; vero che, per ritenere un peso, serva <lb/>tanta forza quanta ne fa quello per scendere<emph.end type="italics"/> (ivi). </s></p><pb xlink:href="020/01/158.jpg" pagenum="139"/><p type="main">

<s>Che il principio delle velocit&agrave; virtuali si ritenesse poi per dubbio <lb/>e inconcludente, s'argomenta dai modi che il Torricelli, il Borelli <lb/>e il Viviani, con tutta l'altra scuola galileiana, tennero nei loro <lb/>meccanici teoremi, nei quali quello stesso principio, non solamente <lb/>non si vede promosso, ma vi &egrave; cansato con ogni pi&ugrave; sollecito studio. </s></p><p type="main">

<s>Antonio Nardi, anzi, nelle <emph type="italics"/>Scene Accademiche,<emph.end type="italics"/> adduce quella <lb/>stessa di Galileo per ragione del suo repudio, dichiarandosi aper&shy;<lb/>tamente &ldquo; che male si persuadono i Meccanici comunemente com&shy;<lb/>pensarsi in una bilancia di disuguali braccia la velocit&agrave; del moto <lb/>con la grandezza del momento, onde cercano di render ragione, <lb/>perch&egrave; questi pesi disuguali, da distanze reciprocamente disuguali, <lb/>pesino ugualmente, ma ci&ograve; non &egrave; in vero cagione dell'equilibrio, <lb/>perch&egrave; cos&igrave; discorrendo s'adduce di un effetto in atto una ragione <lb/>in potenza &rdquo; (MSS. Gal. </s>

<s>Disc. </s>

<s>T. XX, pag. </s>

<s>862). </s></p><p type="main">

<s>N&egrave; era, in quegli ingegni sagaci, senza un giusto motivo il re&shy;<lb/>pudio di una dottrina, dall'altra parte, verissima, perciocch&egrave;, man&shy;<lb/>cando essi del calcolo infinitesimale, sentivano che, senza gli aiuti <lb/>di quello, il principio delle velocit&agrave; virtuali mancava di fondamento <lb/>dimostrativo. </s>

<s>E infatti all'aiuto degli infinitesimi ebbe in ultimo a <lb/>ricorrere il Grandi, per tentar di salvare il teorema galileiano del&shy;<lb/>l'equilibrio dei liquidi nei vasi comunicanti, bench&egrave; non riuscisse, <lb/>a parer nostro, a metterlo al sicuro di quelle argute censure pro&shy;<lb/>mossegli incontro dallo stesso Nardi, nel seguito del discorso ora <lb/>citato. </s>

<s>Si vede dunque, per ridursi alla conclusione, con quanta <lb/>storica verit&agrave; ed esattezza, nella comune opinione, si tenga che i <lb/>principii delle velocit&agrave; virtuali e della composizione de'moti s'in&shy;<lb/>cominciassero ad introdurre e ad applicarsi al trattato delle Mec&shy;<lb/>caniche da Galileo e dalla scuola di lui. </s></p><p type="main">

<s>Si comprende, dopo ci&ograve;, assai facilmente in qual conto si possan <lb/>tener da noi le sentenze di uomini reputati autorevolissimi, quali <lb/>sono il Lagrangia e il Venturi, per tacere di altri. </s>

<s>Che se noi ve&shy;<lb/>niamo a concludere altrimenti da loro, non vorranno i lettori far&shy;<lb/>sene maraviglia, e anzi speriamo che si arrenderanno docili a ci&ograve; <lb/>che ne rappresenta la Storia, le conseguenze della quale, solo, ci <lb/>rendon la ragione di alcuni fatti, e ci scoprono nel tempo stesso o <lb/>la falsit&agrave; o l'insufficienza delle ragioni invocate fin qui, per ispiegarli. </s></p><p type="main">

<s>L'aspetto, sotto cui si &egrave; presentato Galileo agli occhi affascinati <lb/>di tutti, &egrave; proprio quello ch'ei divisava nelle sue intenzioni: a nessun <lb/>altro meglio che a lui &egrave; riuscito mai di farsi credere al mondo <lb/>qual'ei voleva apparire, l'unico sole che sorge, senz'esser prece-<pb xlink:href="020/01/159.jpg" pagenum="140"/>duto da aurora, a illuminare le tenebre del mondo; il creatore in&shy;<lb/>somma dal nulla di ogni scienza sperimentale. </s>

<s>Ma chiunque, dai <lb/>pregiudizi, non s'&egrave; lasciato in tutto privare del senno, comprende <lb/>assai facilmente che una tal pretensione &egrave; contraria ai fatti, ed &egrave; <lb/>contraria ai consueti ordini della natura, com'&egrave; giusto contrario a <lb/>questi stessi ordini che il sole nasca sull'orizzonte, senz'esser pre&shy;<lb/>ceduto da aurora. </s></p><p type="main">

<s>Che sia veramente quella tal pretensione contraria ai fatti, lo <lb/>mostra ad evidenza, ci sembra, la prima parte del nostro Discorso. </s>

<s><lb/>Quale eletto e numeroso stuolo di combattenti per la verit&agrave;, contro <lb/>gli aristotelici errori, non ci pass&ograve; allora ordinata sotto i nostri occhi <lb/>maravigliati? </s>

<s>Or tutti costoro precedettero Galileo, nello speculare <lb/>e nello sperimentare intorno ai fatti della Natura, e gli furono o <lb/>gli potevano esser maestri. </s></p><p type="main">

<s>Che quella pretensione poi di non voler Galileo riconoscere, <lb/>fuor che qualche antico, nessun altro a maestro, sia contraria ai <lb/>consueti ordini della Natura, si dimostr&ograve; da noi infin dai primi prin&shy;<lb/>cipii del nostro Discorso, quando, a investigar l'origine del nostro <lb/>conoscere, ci incontrammo nella necessit&agrave; delle tradizioni. </s>

<s>I fatti <lb/>naturali hanno ultimamente dimostrato che son rimasti lungamente <lb/>immobil&igrave; nella cos&igrave; detta et&agrave; della pietra o in istato anco pi&ugrave; sel&shy;<lb/>vaggio i popoli, infintantoch&egrave; non siano approdati a loro altri popoli <lb/>pi&ugrave; inciviliti. </s>

<s>Da Platone e da Archimede voler d'un salto giungere <lb/>a Galileo sarebbe lo stesso che, da'gioghi della Falterona, voler <lb/>saltare alle foci dell'Arno. </s>

<s>Troppi altri rivi, troppi altri fiumi sono <lb/>scesi per ogni parte e si sono aggiunti a far la piena a quell'acqua. </s></p><p type="main">

<s>&Egrave; forza dunque di confessare che son rimasti ingannati tutti <lb/>coloro, i quali, non ripensando a que'rivi, a que'fiumi e anzi ne&shy;<lb/>gando la loro confluenza, hanno creduto che d'un unico fonte, prin&shy;<lb/>cipio di s&egrave; medesimo, sia scaturita l'ubert&agrave; di quel fiume reale. </s>

<s><lb/>Le nostre conclusioni storiche perci&ograve; cos&igrave; repugnanti all'opinione <lb/>comune svelano quell'inganno, e nelle sue ragioni spiegano il fatto. </s>

<s><lb/>Perciocch&egrave; noi non neghiamo, contrariamente alla verit&agrave; delle cose, <lb/>quella confluenza, ma la mettiamo anzi all'aperto degli artifizii di <lb/>colui, che s'era studiato d'occultare i segreti canali, d'onde gli de&shy;<lb/>riv&ograve; tale abbondanza d'acqua fluente. </s></p><p type="main">

<s>L'albero della scienza, per tornare a quell'altra nostra prima <lb/>immagine, era stato troncato dal ferro infino alla sua ceppaia. </s>

<s>Sorse <lb/>dal taglio un solitario pollone, che attrasse tutti a s&egrave; i succhi nu&shy;<lb/>tritizi ricircolanti nelle barbe sottoterra. </s>

<s>Quella profonda ceppaia, <pb xlink:href="020/01/160.jpg" pagenum="141"/>lungo lavor&igrave;o di secoli, rimasta un po'per natura un po'per arte <lb/>nascosta, second&ograve; le intenzioni di Galileo, in dare a credere che <lb/>non fosse quello veramente un pollone rigoglioso, ma un albero, <lb/>il quale non riconoscesse altra origine che dal suo proprio seme. </s>

<s><lb/>Il nostro scandolezzante discorso ha messo quella sotterranea cep&shy;<lb/>paia allo scoperto, e al miracolo (giacch&egrave; l'albero in che si vuole <lb/>impersonar Galileo, se fosse nato di seme e giunto a s&igrave; grande altezza <lb/>sarebbe miracoloso) ha sostituito un fatto naturale e perci&ograve; vero. </s></p><p type="main">

<s>In altro modo, per ripigliar quell'altra similitudine forse meglio <lb/>appropriata, Galileo institu&igrave; una Tirannide in un Principato decre&shy;<lb/>pito, usando l'arte di tutti i conquistatori, che &egrave; quella di arric&shy;<lb/>chirsi delle spoglie degli uccisi. </s>

<s>Queste spoglie volle far credere che <lb/>non fossero appartenute a nessuno, e il nostro Discorso ha scoperto <lb/>che ci&ograve; non &egrave; vero, come lo attestano i fatti e lo conferma la na&shy;<lb/>tura di ogni conquista. </s>

<s>Ma un'altra pi&ugrave; efficace conferma, che ve&shy;<lb/>ramente l'istaurazione galileiana avesse la natura di una conquista, <lb/>s'ha dal vederne conseguitare al conquistatore i consueti danno&shy;<lb/>sissimi effetti. </s></p><p type="main">

<s>Le usurpazioni, l'esilio, le stragi, che &egrave; costretto a commettere <lb/>colui, il quale vuol solo partecipare del Regno, sono per necessit&agrave; <lb/>occasioni di odii e di vendette, che si suscitano pi&ugrave; che mai feroci, <lb/>dal sangue e dalle ceneri stesse dei vinti. </s>

<s>Di questi odii e di queste <lb/>vendette il Regno di Galileo v&agrave; famoso, n&egrave; par che sieno state fin <lb/>qui ritrovate, di tanto effetto, le giuste e proporzionate cagioni. </s>

<s>Son <lb/>ricorsi, per consueto refugio, all'ignoranza dei tempi e alle reli&shy;<lb/>giose superstizioni, quasi che le innovatrici dottrine dei nostri giorni, <lb/>che son giorni di libert&agrave; e di progressi, non abbiano avuto e non <lb/>sieno per avere sempre, fra gli uomini che adombrano ad ogni <lb/>novit&agrave;, i medesimi sfavorevoli incontri. </s></p><p type="main">

<s>Come si concilii la condanna dei Dialoghi dei Due Massimi <lb/>Sistemi, e la dedica al Papa, del libro <emph type="italics"/>De revolutionibus,<emph.end type="italics"/> &egrave; proble&shy;<lb/>ma lasciato irresoluto ancora da tanti declamatori, ai quali riman <lb/>pure a spiegare come mai fosse tolta libert&agrave; a Galileo di toccar delle <lb/>dottrine del Copernico, e fosse largamente concessa al Bullialdo, <lb/>mutato nome in quello di Filolao. </s>

<s>Come mai cos&igrave; franco il Roberval, <lb/>per fare una burla agli scienziati, facesse pubblicare al Mersanne <lb/>l'<emph type="italics"/>Aristarco,<emph.end type="italics"/> e il Borelli nella Lettera sulla Cometa uscisse fuori in <lb/>abito pitagorico, tanto pauroso, adombrando dell'Inquisitore, pa&shy;<lb/>rendogli di vederselo innanzi sulla punta dei piedi (MSS. Gal. </s>

<s>Cim. </s>

<s><lb/>T. XVIII, c. </s>

<s>125). E chi volesse per curiosit&agrave; seguitare a interrogare <pb xlink:href="020/01/161.jpg" pagenum="142"/>i muti, domanderebbe ancora come si concil&icirc;no i rigorosi divieti <lb/>di Roma colla pubblicazione delle <emph type="italics"/>Theoricae Mediceorum.<emph.end type="italics"/> Il prin&shy;<lb/>cipe Leopoldo st&agrave; in gran trepidazione, perch&egrave; ha saputo che l'In&shy;<lb/>quisitor di Firenze fa difficolt&agrave; d'approvar la stampa del libro. </s>

<s>Manda <lb/>il Redi, il quale torna dicendo che all'Inquisitore era giunta cosa <lb/>totalmente nuova, asserendo che egli <emph type="italics"/>non aveva mai fatta minima <lb/>difficolt&agrave;<emph.end type="italics"/> (ivi, c. </s>

<s>132). </s></p><p type="main">

<s>Ma perch&egrave; da troppe parti tornerebbe provato che nell'igno&shy;<lb/>ranza dei tempi e nelle religiose superstizioni non si trova la causa <lb/>sufficiente degli odii suscitati contro Galileo, noi crediamo per&ograve; di <lb/>non andare errati, attribuendo quella causa alle offese fatte ai tanti, <lb/>che rimasero segno alla sua conquista. </s>

<s>Michelangiolo Ricci, che <lb/>poteva intender quell'animo grande meglio di nessun altro, attri&shy;<lb/>buiva le contradizioni patite da Galileo all'<emph type="italics"/>essersela voluta prendere <lb/>con questo e con quello<emph.end type="italics"/> (ivi, T. XIX, c. </s>

<s>205). N&egrave; senza profonda <lb/>considerazione si pu&ograve; passar questo fatto: che, mentre tanti decla&shy;<lb/>matori son sorti, specialmente oggidi, a rimpiangere sopra le sue <lb/>sventure; egli, Galileo, non ne abbia fatto mai motto, nemmeno nelle <lb/>lettere pi&ugrave; segrete e pi&ugrave; confidenti. </s>

<s>Nella schiettezza della sua co&shy;<lb/>scienza, e nell'altezza del suo proprio senno, troppo ben conosceva <lb/>il vizio di noi uomini di dar la colpa ora a una cosa ora a un altra, <lb/>mentre siam quasi sempre noi stessi occasione e causa della nostra <lb/>sventura. </s>

<s>In conformit&agrave; di questi sentimenti, che non gli abbiamo <lb/>attribuiti a caso, nella solitudine di Arcetri, vicino a lasciar quel <lb/>Regno che avea con tanta contrariet&agrave; conquistato, dava al suo di&shy;<lb/>letto Viviani questo documento: <emph type="italics"/>procurare ad ogni potere di sfug&shy;<lb/>g&igrave;re ogni lite e controversie letterarie con chi si sia<emph.end type="italics"/> (ivi, T. XVII, <lb/>c. </s>

<s>69). Egli riport&ograve; &egrave; vero le pene delle liti e delle controversie <lb/>da s&egrave; in tanti modi contro s&egrave; provocate, ma gli riman la gloria <lb/>d'avere egli solo recato inestimabili benefizi alla scienza. </s></p><p type="main">

<s>Come mai il male sia quasi una necessit&agrave;, d'onde tante volte <lb/>vedesi derivare un gran bene, &egrave; un mistero che a noi non tocca <lb/>d'investigare. </s>

<s>Ma &egrave; forza in ogni modo riconoscere che i vizii, no&shy;<lb/>tati da noi cos&igrave; liberamente e irreverentemente se si vuole, nella <lb/>vita scientifica di Galileo, furono una necessit&agrave; a condur la difficile <lb/>impresa. </s>

<s>Perch&egrave;, o la si rappresenta la scienza sotto l'immagine <lb/>di un albero, e ci bisognava la violenza del ferro per recidere i <lb/>rami vecchi e farvi sopra ripullulare un ramo nuovo: o la si rap&shy;<lb/>presenta sotto l'immagine di un Regno, e bisognava contrucidare <lb/>i fratelli, perch&egrave; il potere vacillante e disperso, si riducesse alle <pb xlink:href="020/01/162.jpg" pagenum="143"/>mani di un solo. </s>

<s>Contristati fin qui dai mali licenziosi e dalle pene <lb/>della Tirannide, passiamo a rasserenare il pensiero ne'grandissimi <lb/>benefizi che ne son conseguiti. </s></p><p type="main">

<s><emph type="center"/>III.<emph.end type="center"/></s></p><p type="main">

<s>Il primo e principale dei benefizi che possa un conquistatore <lb/>arrecare al suo principato, e che sarebbe sufficiente per s&egrave; solo a <lb/>dover perdonargli le offese, &egrave; quello d'istituirvi ordini savi, per i <lb/>quali possa la Repubblica prosperamente vivere e progredire. </s>

<s>Galileo <lb/>veramente incominci&ograve; a instituire questa saviezza di ordini, nella <lb/>Repubblica delle scienze, le quali ebbero perci&ograve; di qui il pi&ugrave; valido <lb/>impulso ai loro progressi. </s>

<s>Fra'due pi&ugrave; grandi antichi Maestri e Le&shy;<lb/>gislatori dell'umana sapienza, prefer&igrave; i plaeiti di Platone, in con&shy;<lb/>formit&agrave; dei quali sentenziava che &ldquo; il voler trattar le questioni na&shy;<lb/>turali, senza Geometria, &egrave; tentar di far quello che &egrave; impossibile ad <lb/>esser fatto &rdquo; (Alb. </s>

<s>I, 224). La vera Filosofia, egli dice &ldquo; &egrave; scritta in <lb/>questo grandissimo libro che continuamente ci sta aperto innanzi <lb/>agli occhi (io dico l'Universo) ma non si pu&ograve; intendere, se prima <lb/>non s'impara a intender la lingua e conoscere i caratteri ne'quali <lb/>&egrave; scritto. </s>

<s>Egli &egrave; scritto in lingua matematica, e i caratteri son trian&shy;<lb/>goli, cerchi ed altre figure geometriche, senza i quali mezzi &egrave; im&shy;<lb/>possibile intenderne umanamente parola: senza questi &egrave; un aggirarsi <lb/>vanamente per un oscuro laberinto &rdquo; (Alb. </s>

<s>IV, 171). </s></p><p type="main">

<s>Quell'altra Filosofia pi&ugrave; comunemente segu&igrave;ta gli parve un'or&shy;<lb/>gogliosa vanit&agrave;, una temerit&agrave; estrema. </s>

<s>&ldquo; Estrema temerit&agrave; mi &egrave; <lb/>parsa sempre quella di coloro che voglion fare la capacit&agrave; umana <lb/>misura di quanto possa e sappia operar la Natura &rdquo; (Alb. </s>

<s>I, 114). <lb/>Che se Aristotile fa scaturir le cause degli effetti naturali dalla <lb/>dialettica de'suoi sillogismi, Galileo gli si oppone cos&igrave; con animosa <lb/>franchezza: &ldquo; A me pare che la Logica insegni a conoscere se i <lb/>discorsi e le dimostrazioni.... procedono concludentemente, ma che <lb/>ella insegni a trovare i discorsi.... non credo io &rdquo; (Alb. </s>

<s>XIII, 135). <lb/>E se il Principe dei peripatetici va cos&igrave; studiosamente in cerca delle <lb/>argute speculazioni, e quanto son pi&ugrave; recondite, tanto pi&ugrave; volentieri <lb/>le d&agrave; per vere; Galileo, tutto al contrario sentenzia che &ldquo; la pi&ugrave; <lb/>ammirabile e pi&ugrave; da stimarsi condizione delle scienze dimostrative <lb/>&egrave; lo scaturire e pullulare da principii notissimi (ivi, pag. </s>

<s>90). </s></p><pb xlink:href="020/01/163.jpg" pagenum="144"/><p type="main">

<s>Ma a poco gioverebbe istituire ordini savi un principe, che non <lb/>volesse o non sapesse seguirli con gli esempi. </s>

<s>Ci&ograve;, come si vide, <lb/>tanto poco giov&ograve; al Verulamio, che per questo solo and&ograve; a vuoto <lb/>la sua cos&igrave; ben divisata Instaurazione. </s>

<s>Galileo invece non si con&shy;<lb/>tent&ograve; di segnar la via o di ordinare il campo della battaglia, usc&igrave; <lb/>fuori con le armi in mano, contro l'errore, e tanta gloria riport&ograve; <lb/>dalle sue vittorie e tanta autorit&agrave; ne consegu&igrave;, che, non Tirannide <lb/>apparve o si disse la sua, ma legittimo principato. </s>

<s>Or questo &egrave; un <lb/>altro benefizio grandissimo recato alla scienza da quell'uomo. </s></p><p type="main">

<s>L'intrattenersi qui a noverar quelle vittorie parrebbe opera <lb/>vana, perch&egrave; troppo anzi bene son conosciute da tutti e da tutti <lb/>cos&igrave; magnificate, che Colui, il quale le riport&ograve;, non &egrave; solamente <lb/>tenuto come principe valoroso, ma &egrave; adorato come un Nume. </s>

<s>Or <lb/>perch&egrave; questa &egrave; una esagerazione, e ogni vizio conduce nell'errore, <lb/>non far&agrave; maraviglia se da noi si asserisce che Galileo, da'suoi stessi <lb/>adoratori, &egrave; cos&igrave; poco inteso e cos&igrave; poco studiato. </s>

<s>Chi fa oggid&igrave; pi&ugrave; <lb/>speciale professione di studii galileiani, non entra mica addentro <lb/>alle speculazioni della gran mente: crede aver fatto assai a venire <lb/>a contarci del suo processo, delle amicizie, del numero de'suoi libri <lb/>stampati, o dei manoscritti. </s>

<s>E ha ragione costui, perch&egrave;, se quella <lb/>mente divina &agrave; un sacro tempio, non debbono entrarvi dentro a <lb/>celebrarne i misteri piedi profani. </s></p><p type="main">

<s>Ma a noi per verit&agrave; &egrave; sembrato altrimenti. </s>

<s>Persuasi che Galileo <lb/>&egrave; un grand'uomo, ma pur un uomo come noi, soggetto a vizii e <lb/>ad errori, gli ci siamo avvicinati per vederlo e intenderlo meglio, <lb/>e abbiamo imparato da lui a non credere e sostener per vera una <lb/>cosa, perch&egrave; l'ha detta un uomo. </s>

<s>Que'fanatici, che inorridiscono <lb/>a sentir dire che Galileo ha sbagliato, non imitano certo i pi&ugrave; affe&shy;<lb/>zionati e valorosi discepoli, come il Sagredo l'Aggiunti il Nardi, il <lb/>Viviani stesso, i quali notarono con libert&agrave; gli errori detti dal loro <lb/>venerato Maestro, e ne lasciarono scritte argute censure. </s>

<s>Non si <lb/>avvedono quegli stessi fanatici che, se fossero nati tre secoli addietro, <lb/>si sarebbero sottoscritti nella lista dei Cremonini, e non ripensano <lb/>che Aristotile, verso cui si commisero tante irreverenze, era vene&shy;<lb/>rando a quei tempi, ben assai pi&ugrave; di quel che non sia ora lo stesso <lb/>Galileo, lodato a cielo, perch&egrave; fu il pi&ugrave; irriverente di tutti. </s></p><p type="main">

<s>Ripigliando il costrutto del discorso interrotto si voleva dunque <lb/>dire che giusto appunto, per essere le opere scientifiche di Galileo <lb/>esageratamente note, e perci&ograve;, ci si perdoni il bisticcio, ignote, ave&shy;<lb/>vano bisogno di essere con pi&ugrave; discrezione esaminate. </s>

<s>Ma perch&egrave; <pb xlink:href="020/01/164.jpg" pagenum="145"/>dall'altra parte si pu&ograve; dir che questo &egrave; l'intento principale di tutta <lb/>la nostra Storia, crediamo perci&ograve; di dovercene passare, contentan&shy;<lb/>doci solo di notare una cosa: che mentre gli adoratori attribuiscono <lb/>a Galileo, perch&egrave; qualche uomo autorevole e male informato glie <lb/>l'ha suggerito, meriti che non gli appartengono, non si curano poi <lb/>di riconoscerne e di esaltarne i meriti veri. </s></p><p type="main">

<s>Nella scienza del moto i meriti veri di Galileo incominciano <lb/>dalla dimostrazione delle leggi dei gravi, che cadono naturalmente <lb/>o scendono per gli archi di un cerchio. </s>

<s>Tutte le altre scoperte, che <lb/>precedono a questa, son retaggio di una scienza pi&ugrave; antica. </s>

<s>Di qui <lb/>&egrave; che, se i suoi ammiratori male a ragione lo dicono creatore della <lb/>Dinamica, troppo debolmente, dall'altra parte mettono in opera le <lb/>loro armi, per chiarir l'efficacia, che ebbero le galileiane scoperte <lb/>in aprire alla Meccanica la via de'suoi gloriosi progressi. </s></p><p type="main">

<s>In Idrostatica, Galileo riman forse inferiore a Simeone Stevino. </s>

<s><lb/>Il Discorso intorno alle Galleggianti &egrave; uno splendido commento alle <lb/>teorie di Archimede, ma se pure la scienza vi si illustra, non per&ograve; <lb/>si promuove. </s>

<s>Le tavolette d'ebano, o d'altra materia pi&ugrave; grave in <lb/>specie dell'acqua, non galleggiano per la spinta idrostatica di sotto <lb/>in su, come si poteva concludere dai teoremi steviniani, ma si so&shy;<lb/>stengono a galla, perch&egrave;, secondo Galileo, aderiscono all'aria, la quale <lb/>per attrazione le tien sospese come il ferro la calamita. </s>

<s>Nonostante, <lb/>l'aver dichiarate cos&igrave; eloquentamente quelle dottrine, rimaste nei <lb/>libri di Archimede, o ignorate o male intese, fu merito grande, e <lb/>occasione che altri, come poi presto si vide nel Castelli e nel Tor&shy;<lb/>ricelli, vi facessero grandi progressi. </s></p><p type="main">

<s>Nell'Idraulica, qualunque sieno le pretensioni degli idolatri, <lb/>Galileo &egrave; seguace del Castelli, ma il Trattato in forma di lettera <lb/>sul fiume Bisenzio, bench&egrave; la matematica astrattezza delle dottrine <lb/>non le faccia applicabili alla pratica delle acque correnti, apri no&shy;<lb/>nostante largamente la via a nuove speculazioni. </s></p><p type="main">

<s>Nell'Astronomia, l'ingegno in Galileo concorse colla fortuna. </s>

<s><lb/>Il felice accorgimento che egli ebbe di badare, non alla chiarezza <lb/>dei vetri ma alla figura, lo fece uno de'pi&ugrave; abili fabbricatori del <lb/>canocchiale, che, rivoltolo alle plaghe del cielo, gli svel&ograve; quelle sue <lb/>gran maraviglie. </s>

<s>Ma in tutto ci&ograve;, per cui vien esaltato lo scopritore, <lb/>ha pi&ugrave; merito la fortuna che non l'ingegno, o per dir pi&ugrave; giusto, <lb/>quello &egrave; merito di un esperto meccanico, no di uno scienziato. </s>

<s>Cos&igrave;, <lb/>n&egrave; il Fontana, n&egrave; il Campani, n&egrave; il Divini, squisitissimi artefici di <lb/>canocchiali, hanno giusto merito perci&ograve; di esser chiamati astronomi. </s></p><pb xlink:href="020/01/165.jpg" pagenum="146"/><p type="main">

<s>Astronomo &egrave; Galileo quando, posato lo strumento e chiusi gli <lb/>occhi della vista materiale, apre quelli dell'intelletto a specular sui <lb/>fenomeni osservati intorno a Giove, o nella faccia della Luna e del <lb/>Sole. </s>

<s>Astronomo &egrave; quando inventa nuovi strumenti e divisa nuovi <lb/>metodi a prefinir, nei moti planetarii, gli spazii giustissimi e i tempi. </s>

<s><lb/>S'ammira e s'esalta, per avere egli il primo scoperto il mondo <lb/>gioviale, e se alcuno mai muove voce d'averlo preceduto nella sco&shy;<lb/>perta, &egrave; afferrato dal furore degli zelanti, che gli soffocano le parole <lb/>nella strozza. </s>

<s>Ma quando pur fosse che o Simon Mario o altri aves&shy;<lb/>sero veduto le quattro lune intorno a Giove prima di Galileo, che <lb/>vorrebb'egli dir ci&ograve;, se non che que'tali avevano strumenti pi&ugrave; <lb/>squisiti, e occhi pi&ugrave; acuti di lui? </s>

<s>Or chi oserebbe dire che ci&ograve; non <lb/>fosse possibile? </s></p><p type="main">

<s>Il merito dunque non consiste qui, e chi ce lo fa consistere <lb/>mal provvede alla gloria di Galileo. </s>

<s>Il merito vero, e per cui ver&shy;<lb/>rebbe giustamente esaltato quell'uomo, consiste nell'aver dimostrato <lb/>esser le stelle circungioviali veramente lune, e nell'averne esatta&shy;<lb/>mente misurati i tempi periodici e le medie distanze dal centro di <lb/>Giove. </s>

<s>Ma chi &egrave;, tra i fanatici ammiratori, che si sia curato d'in&shy;<lb/>vestigare per quali ingegnosissimi metodi e strumenti riuscisse con <lb/>tanta felicit&agrave; Galileo, in quest'operazione affatto nuova nell'Astro&shy;<lb/>nomia? </s>

<s>Parve aver fatto una grande scoperta a colui che trov&ograve; e <lb/>dette alla luce l'Effemeridi de'Satelliti di Giove, ma codeste son le <lb/>scompaginate e rimescolate ossa di un cadavere; per cui vera sco&shy;<lb/>perta sarebbe stata piuttosto l'infondere in quelle membra il primo <lb/>loro, e antico spirito della vita. </s></p><p type="main">

<s>In ogni modo, tanta varia novit&agrave; di scoperte e di dottrine, <lb/>uscite fuori con quella splendida veste che ritraeva cos&igrave; bene in s&egrave; <lb/>la magnificenza del pallio filosofico di Platone, conferiva, per una&shy;<lb/>nime consenso a Galileo l'autorevole dignit&agrave; del Principato. </s>

<s>Ecco <lb/>felicemente conseguito il fine della nobile e altissima impresa. </s>

<s>Tutti <lb/>i dotti di que'tempi, non eccettuato il Keplero che primeggia fra <lb/>tutti, s'inchinano a quella Autorit&agrave; o con le voci congratulanti o <lb/>col silenzio. </s>

<s>Quei che possono ascoltar la viva voce del Maestro di <lb/>tante verit&agrave; o aver con lui familiari colloqui, e corrispondenza epi&shy;<lb/>stolare, se ne tengon beati. </s></p><p type="main">

<s>Son de'principali fra costoro Daniele Antonini, che il vuoto <lb/>lasciatogli dentro dalla vita diplomatica riempiva di speculazioni e <lb/>di fisici sperimenti, Cesare Marsili, studioso di Astronomia e delle <lb/>propriet&agrave; del magnete, Paolo Aproino inventore del corno acustico, <pb xlink:href="020/01/166.jpg" pagenum="147"/>e Giovan Francesco Sagredo, la pi&ugrave; amabile figura, fra le tante <lb/>comparse sopra questa magnifica scena. </s>

<s>Gentiluomo e patrizio ve&shy;<lb/>neziano, fra le delizie della vita signorile e le gravi cure della poli&shy;<lb/>tica, attende alla fabbrica dei vetri per i canocchiali e de'cannellini <lb/>per uso dei termometri, co'quali, da s&egrave; perfezionati, sperimenta <lb/>ne'varii ambienti le varie temperature dell'aria. </s>

<s>Tanti anni avanti <lb/>all'invenzione dello strumento torricelliano e della macchina pneu&shy;<lb/>matica, egli &egrave; il primo a far l'esperienza del suono nel vuoto, e <lb/>indovina la vera teorica della visione, senza pensare al Porta o aver <lb/>letto ancora il Keplero. </s>

<s>Ei, con libera franchezza, sostiene in tal <lb/>proposito, la sua propria opinione, contro il diverso parere di Ga&shy;<lb/>lileo, che a lui sembra e apertamente lo dichiara per un errore. </s></p><p type="main">

<s>Anche l'arte si rivolse a riconoscere l'autorit&agrave; di questo prin&shy;<lb/>cipato, presaga forse de'nuovi benefizi e iniziatrice de'nuovi connubi, <lb/>che sarebbe per contrar colla scienza. </s>

<s>Bell'esempio di questi nuovi <lb/>connubi l'abbiamo in due eccellenti pittori, Domenico Passignani <lb/>e Lodovico Cardi Cigoli, che appuntano la matita dei pittori a di&shy;<lb/>segnare le macchie solari. </s>

<s>Anzi il Passignani ne fu osservatore cos&igrave; <lb/>diligente e appassionato, da venire in contesa con Galileo. </s>

<s>A lui in <lb/>ogni modo si dee la prima osservazione di quelle profondit&agrave; vora&shy;<lb/>ginose, che ammannirono al Wilson, tanti anni dopo, le sue teorie <lb/>(Alb. </s>

<s>VIII, 170). a lui le prime osservazioni delle montuosit&agrave; nella <lb/>circonferenza lunare (MSS. Galil. </s>

<s>Div. </s>

<s>II. P. I. T. VII, c. </s>

<s>12). </s></p><p type="main">

<s>Il Cigoli lasci&ograve; manoscritto un libro di Prospettiva, a cui, per <lb/>essere stampato, non manc&ograve; nemmeno l'approvazione ecclesiastica <lb/>sottoscritta nel d&igrave; 6 di Febbraio 1628 (MSS. Gal. </s>

<s>Div. </s>

<s>III. T. VIII, <lb/>c. </s>

<s>107). L'Alberti e il Vinci avevano immaginato qualche ingegno, <lb/>per eseguire con pi&ugrave; facilit&agrave; e prestezza, che non per le solite regole <lb/>delle linee, i disegni di Prospettiva, ma il Cigoli riconoscendoli <lb/>all'arte di piccolo aiuto, invent&ograve; due nuovi strumenti, nella loro <lb/>semplicit&agrave; ingegnosissimi, che egli nel II libro del suo Trattato <lb/>minutamente descrive nelle parti e nell'uso. </s>

<s>Bench&egrave; le regole, che <lb/>ivi egli espone dell'arte sua, sieno puramente pratiche, senz'altra <lb/>dimostrazione; non si pu&ograve; tuttavia lasciar di notare che v'&egrave; trattata <lb/>un importante questione scientifica, ed &egrave; quella del modo e del <lb/>luogo dove si rappresenta la vista. </s>

<s>Che la vista non si faccia nella <lb/>parte anteriore dell'occhio, e nemmeno del centro del cristallino, <lb/>come diceva Galileo, il Pittore lo dimostra con argomenti e con <lb/>esperienze si nuove, che se ne potrebbe onorar degnamente qua&shy;<lb/>lunque filosofo. </s>

<s>&ldquo; Quando si fa qualche concorso di materia fra il <pb xlink:href="020/01/167.jpg" pagenum="148"/>cristallino e la cornea, egli dice, ci par veder per l'aria alquanto <lb/>lontano qualche cosa di simile alla tela del ragno, e cos&igrave; di colore <lb/>oscuro...... il che ci fa manifesto che la sensazione &egrave; pi&ugrave; interna <lb/>dell'umore acqueo e non pare che possa essere il centro del cri&shy;<lb/>stallino perch&egrave; come centro non &egrave; capace della diversa quantit&agrave; &rdquo; <lb/>(ivi, c. </s>

<s>25). </s></p><p type="main">

<s>Il Cigoli per&ograve;, cos&igrave; come il Sagredo, erano alieni dal far pro&shy;<lb/>fessione di scienza: l'Antonini, il Marsili, l'Aproino non ne ave&shy;<lb/>vano nemmeno essi la pretensione, il Passignani che pretendeva <lb/>qualche cosa di pi&ugrave;, come impotente di studii e di esercizi letterari, <lb/>era sotto sotto da'suoi amici deriso. </s>

<s>Ma bisognava pure che l'au&shy;<lb/>torit&agrave; del nuovo principato galileiano fosse primieramente ricono&shy;<lb/>sciuta da coloro che esercitavano il ministero della scienza o nel <lb/>pubblico insegnamento delle scuole o ne'libri. </s>

<s>Nelle scuole per&ograve; i <lb/>professori facevano assai, se approvavano col silenzio. </s>

<s>Fra coloro poi <lb/>che diffondevano la scienza sperimentale ne'libri val per tutti l'esem&shy;<lb/>pio del genovese Giovan Batista Baliani. </s></p><p type="main">

<s>Chi dipinse il Baliani invidioso delle glorie di Galileo e suo <lb/>competitore, non lesse bene addentro nell'animo, e ne'libri di lui. </s>

<s><lb/>Il Trattato <emph type="italics"/>De motu naturali<emph.end type="italics"/> &egrave;, nell'aperta intenzione dello stesso <lb/>autore, una conferma dei teoremi dimostrati ne'Dialoghi delle <lb/>Scienze Nuove, conclusi per una via diversa e in un altro modo, <lb/>che, per il lucido ordine e per la brevit&agrave;, riesce maraviglioso. </s>

<s>Chi <lb/>vuol vedere qual fosse l'animo del filosofo genovese verso il Prin&shy;<lb/>cipe della Nuova Filosofia, ne legga il commercio epistolare, spe&shy;<lb/>cialmente l&agrave; dove la libert&agrave; del giudizio concilia fede alla sincerit&agrave; <lb/>dell'ossequio. </s>

<s>Cos&igrave; l&agrave; dove critica la teoria delle comete data nel <lb/>Saggiatore (Alb. </s>

<s>Supplem. </s>

<s>pag. </s>

<s>136); cos&igrave; l&agrave; dove dice che non &egrave; <lb/>tolta una delle maggiori difficolt&agrave;, nel risolvere, nell'ultimo Dialogo <lb/>dei Due Massimi Sistemi, il maraviglioso problema del flusso del <lb/>mare (Alb. </s>

<s>IX, 266). </s></p><p type="main">

<s>Con fiducia di discepolo ricorre il Baliani a Galileo, quando <lb/>vuol saper quanto vada lungo il pendolo che batte i secondi, per <lb/>servirsene, fra i tanti usi, a quello di trovare le longitudini; quando <lb/>vuol imparare il modo di ritrovare il peso specifico dell'aria, quando <lb/>conferisce con lui i suoi pensieri intorno alla pressione atmosferica, <lb/>per cui si sostien l'acqua dentro i sifoni, non pi&ugrave; su che a una <lb/>determinata altezza. </s></p><p type="main">

<s>Ma che ci tratteniamo noi con gli ammiratori seguaci o dietro <lb/>a coloro che ne professarono le dottrine, con ossequio di discepoli? <pb xlink:href="020/01/168.jpg" pagenum="149"/>A confermar Galileo nel principato della scienza conferirono massi&shy;<lb/>mamente gli stessi suoi contradittori. </s>

<s>Si venne a verificare cos&igrave; anche <lb/>da questa parte quella approvata sentenza, che i nostri pi&ugrave; grandi <lb/>benefattori sono i nostri propri nemici. </s>

<s>Quanti gran benefizi infatti <lb/>non vennero alla scienza dalle contradizioni dei peripatetici? </s>

<s>Si dee <lb/>senza dubbio a costoro l'aver dato occasione a Galileo di scrivere <lb/>pi&ugrave; che la met&agrave; de'suoi libri, e dei pi&ugrave; belli: essi, nel fare ogni <lb/>sforzo di toglierla, gli confermarono in fronte la corona del Principato. </s></p><p type="main">

<s>E ora che, co'savii ordini instaurati e coll'esempio del suo <lb/>valore, &egrave; riuscito a conquistarsi quella corona, concludiamo i gran&shy;<lb/>dissimi benefizi che alla Repubblica della scienza seguitarono da <lb/>tale conquista. </s>

<s>A far ci&ograve; non bisogna oramai a noi troppo lunghe <lb/>parole, ritornando indietro colla memoria ai principii del nostro <lb/>Discorso. </s>

<s>Dicemmo infatti che la miglior maniera da ringiovanire <lb/>l'albero della scienza, per troppo lunga et&agrave; trascorso, era quello di <lb/>ravviare i succhi nutritivi dispersi, e condensar gli spiriti dissipati <lb/>in un tronco solo. </s>

<s>Questo &egrave; ci&ograve; appunto che riusc&igrave; di fare a Galileo, <lb/>e per cui egli &egrave; cos&igrave; meritamente glorioso. </s></p><p type="main">

<s>Noi rassomigliammo col Verulamio la grande impresa a una <lb/>conquista politica, nella quale la forza sola non basta, se non v&agrave; <lb/>spesso congiunta coll'astuzia. </s>

<s>Di queste astuzie, da noi di sopra <lb/>notate nella vita scientifica di Galileo, molti saranno rimasti scan&shy;<lb/>dalizzati, ma costoro se non s'acquietano ai fatti si acquietino al&shy;<lb/>meno in quel principio che, nella infermit&agrave; delle operazioni umane, <lb/>suol prevalere alla retta morale, del fine che giustifica i mezzi. </s>

<s>Tru&shy;<lb/>cidare i fratelli e arricchirsi delle loro spoglie, &egrave; un mezzo illecito, <lb/>ma pure era necessario a instituire una Monarchia nella scienza, <lb/>com'&egrave; necessario al fine del villico il trucidare in un albero i rami. </s>

<s><lb/>Fossero rimaste le varie speculazioni e le varie scoperte disperse <lb/>nello Stevino, nel Santorio, nel Cavalieri e in tanti altri, non sareb&shy;<lb/>bero riuscite ai progressi delle scienze sperimentali tanto efficaci, <lb/>come digeste in uno stomaco solo, d'onde si dispenseranno a tante <lb/>membra la vita e gli alimenti. </s></p><p type="main">

<s>Ripensando quello a che fu dalla Provvidenza riserbato Galileo, <lb/>chi meglio lo riconosce nell'esser suo, e pi&ugrave; l'ammira. </s>

<s>Egli non <lb/>fu, ne poteva essere il creatore della scienza sperimentale, ma ne <lb/>fu il rigeneratore, e tra poco vedremo la fecondit&agrave; della sua prole. </s>

<s><lb/>Prima per&ograve; convien che ci tratteniamo intorno agli ordini e agli <lb/>effetti di quell'altra Instaurazione, a cui s'accennava gi&agrave; in quel <lb/>primo nostro introdursi a discorrer di questa. </s></p><pb xlink:href="020/01/169.jpg" pagenum="150"/><p type="main">

<s><emph type="center"/>IV.<emph.end type="center"/></s></p><p type="main">

<s>Non aveva ancora Galileo dato l'ultima mano alla costituzione <lb/>del suo nuovo Regno, che si leva dalla montagnosa Bretagna un <lb/>vento impetuoso a ferire, abbattere e disperdere tutto ci&ograve; che egli <lb/>incontra per via. </s>

<s>Quel vento &egrave; l'orgoglio filosofico di Renato Car&shy;<lb/>tesio, il quale proclamando ad alta voce che tutto il mondo era fino <lb/>a quel tempo vissuto nelle tenebre e nell'errore, viene ad abbat&shy;<lb/>tere il tristo e buio tugurio dell'ignoranza per sostituire ad esso, <lb/>di sua propria mano ricostruito, il nuovo edifizio della scienza. </s></p><p type="main">

<s>&Egrave; questo dunque un conquistatore ben assai pi&ugrave; ardito: Galileo <lb/>rispett&ograve; i placiti dell'antica filosofia, e fecesi discepolo di Platone, <lb/>seguace di Archimede; il suo Regno &egrave; circoscritto, e non esce fuori <lb/>della cerchia dei fatti naturali. </s>

<s>Il Cartesio invece protesta di non <lb/>riconoscere tradizioni di nessuna maniera; la sua impresa &egrave; quella <lb/>di voler da s&egrave; solo restaurar la scienza universale. </s>

<s>Se egli avesse <lb/>confidato in segreto a qualche suo savio amico questa ardita inten&shy;<lb/>zione, ei ne lo avrebbe senza dubbio distolto, dicendogli non poter <lb/>esser quella altro che una follia. </s>

<s>Ma pure &egrave; mirabile che uscito il <lb/>Cartesio in pubblico, a divisare gli ordini e i modi di quella sua <lb/>titanica impresa, tutt'altro ch'esser tenuto folle, ebbe plauso dalla <lb/>turba maravigliata e titolo di sapiente. </s></p><p type="main">

<s>Il libro, in cui si divisano quegli ordini e quei modi, usc&igrave; in <lb/>pubblico nel 1637 con un titolo, che si tradusse in quello di <emph type="italics"/>Spe&shy;<lb/>cimina Fhilosophiae<emph.end type="italics"/> o altrimenti <emph type="italics"/>Dissertatio de methodo recte re&shy;<lb/>gendae rationis.<emph.end type="italics"/> La bellezza del patrio l&igrave;nguaggio, in cui prima usc&igrave; <lb/>fuori alla luce il libro, fu una delle principali cagioni per cui ri&shy;<lb/>masero cos&igrave; dolcemente allettati, e quasi si direbbe sedotti i lettori. </s>

<s><lb/>Altra poi di quelle cagioni fu senza dubbio un aura conciliatrice <lb/>di pace nella prima, e un approvato sentimento di verit&agrave; nell'altre <lb/>due regole provvisorie da seguirsi, intanto che, distrutta la vecchia, <lb/>non si sia rifatta dall'Autore e ricostruita la nuova scienza morale. </s></p><p type="main">

<s>L'efficacia poi di queste regole sull'animo del lettore, e quel&shy;<lb/>l'aura conciliatrice di pace che si diceva, si rendono manifeste dal <lb/>considerar che la bellezza e la verit&agrave; di quelle stesse regole son che <lb/>tolgono ai divisamenti dell'Autore il carattere della follia. </s>

<s>Perci&ograve; <pb xlink:href="020/01/170.jpg" pagenum="151"/>questi son passati e quasi non sentiti in grazia di quelle, e la con&shy;<lb/>tradizione, che fra loro &egrave; manifesta, finisce poi di operare la seduzion <lb/>dell'effetto. </s></p><p type="main">

<s>Che fra le regole del metodo e i divisamenti del Cartesio passi <lb/>un'aperta contradizione si prova con facilit&agrave; in poche parole. </s>

<s>&Egrave; la <lb/>prima di quelle regole infatti che si debbono seguir le usanze del <lb/>proprio paese. </s>

<s>Questa regola &egrave; senza dubbio conciliatrice di pace, <lb/>ma &egrave; in aperta contradizione coi principii professati dall'Autore, <lb/>secondo i quali son quelle usanze false, perch&egrave; suggerite dalla igno&shy;<lb/>ranza universale. </s></p><p type="main">

<s>La terza regola bellissima &egrave; che non si dee voler mutar l'or&shy;<lb/>dine al mondo, ma alle nostre cupidigie. </s>

<s>Ora se si trasporta questa <lb/>regola dalla Filosofia morale, alla naturale, contradice apertamente <lb/>ai metodi filosofici del Cartesio, conforme ai quali il mondo si muta <lb/>veramente a seconda delle cupidigie del nostro intelletto. </s>

<s>E di ci&ograve; <lb/>basti la famosa teoria dei vortici per esempio. </s></p><p type="main">

<s>Senz'altro, s'intravede gi&agrave; che se Galileo &egrave; il Platone di questo <lb/>nuovo periodo del risorgimento della scienza, il Cartesio &egrave; l'Aristo&shy;<lb/>tile. </s>

<s>E tanto &egrave; vivo e incarnato lo spirito del filosofo di Stagira nelle <lb/>membra del Filosofo bretone, che d'ogni parte ne traspira la so&shy;<lb/>miglianza. </s>

<s>Aristotile accomoda la Natura alla capacit&agrave; del proprio <lb/>intelletto, e la ragion dei fatti la fa scaturire dall'artificiosa dialet&shy;<lb/>tica dei sillogismi. </s>

<s>Perci&ograve; quanto una di queste ragioni &egrave; pi&ugrave; sottile <lb/>e arguta, tanto ha secondo lui pi&ugrave; sapore di vero. </s>

<s>La facilit&agrave; di <lb/>spiegare i fatti naturali si aborrisce da lui e dalla sua scuola, come <lb/>segno della impotenza della ragione a dominarli. </s></p><p type="main">

<s>Che da un simile principio sien pure informate le fisiche spe&shy;<lb/>culazioni del Cartesio, due soli fra i molti esempii piace a noi di <lb/>sciegliere per provarlo, e son questi due esempi l'uno tolto dalla <lb/>ragion ch'ei rende dell'origine dei venti, l'altro dell'origine delle <lb/>fonti. </s>

<s>La vecchia fisica ammetteva che le esalazioni di sotto terra <lb/>commovessero i vapori dell'aria, e cos&igrave; avessero origine i venti. </s>

<s>Al <lb/>Cartesio troppo facile parve questa spiegazione, n&egrave; men semplice <lb/>e quasi puerile gli sembr&ograve; quell'altra delle dilatazioni e dei con&shy;<lb/>densamenti, che l'avvicendarsi del calore e del freddo producono <lb/>sulla mole dell'aria. </s>

<s>Perci&ograve; soccorse cos&igrave; a quel difetto colle arguzie <lb/>della sua nuova filosofia. </s>

<s>Immagin&ograve; che le dilatazioni, da cui vien <lb/>commossa l'aria, si producessero nelle minime particelle del vapore, <lb/>le quali, agitate e mosse in giro dal secondo elemento, occupano <lb/>maggiore spazio, a somiglianza di una bandiera menata in volta <pb xlink:href="020/01/171.jpg" pagenum="152"/>dalle agili mani dell'alfiere. </s>

<s>&ldquo; Quum vaporis formam habent, agi&shy;<lb/>tatio illarum adeo est concitata ut celerrime rotentur in omnes <lb/>partes, quemadmodum baculo per quem funiculus traiectus est, ce&shy;<lb/>lerrime rotato, videmus funiculum rectum atque extensum porrigi &rdquo; <lb/>(Meter. </s>

<s>Francof. </s>

<s>1692, pag. </s>

<s>131). </s></p><p type="main">

<s>La scmplicit&agrave; della fisica antica ammetteva che dagli stillicidi <lb/>delle nevi e dalla infiltrazione delle acque piovane avessero la loro <lb/>origine le fonti. </s>

<s>Ma il Cartesio, come di sopra era ricorso all'arguzia <lb/>delle banderuole, cos&igrave; qui ricorre all'arguzia degli alambicchi. </s>

<s>Im&shy;<lb/>magin&ograve; che le acque del mare s'insinuassero di sottoterra e si sol&shy;<lb/>levassero allo stato di vapori, i quali condensati poi dal freddo sotto <lb/>le cupole dei monti, giusto come nel cappello dell'alambicco, tor&shy;<lb/>nassero ad apparire qua e l&agrave; in acque sorgenti. </s></p><p type="main">

<s>Questa nuova sorta di Filosofia naturale, che tanto al vivo si <lb/>rassomiglia alla vecchia filosofia di Aristotile, viziata nelle radici, <lb/>non poteva non riuscir, al pari di quella, sterile di buoni frutti. </s>

<s><lb/>Quali frutti in verit&agrave; dette la Filosofia cartesiana alle scienze speri&shy;<lb/>mentali? </s>

<s>&Egrave; vero che il celebre Autore della Dissertazione del Me&shy;<lb/>todo formul&ograve; nella Diottrica la legge delle rifrazioni, e divis&ograve; nella <lb/>Meteorologia il modo vero del dipingersi e del rappresentarsi ai <lb/>nostri occhi l'iride in cielo, ma sta a vedere se questi sieno ve&shy;<lb/>ramente frutti della Filosofia cartesiana. </s>

<s>Il Newton, a principio gli <lb/>credette tali, ma poi si ridisse, e attribu&igrave; la legge delle rifrazioni <lb/>allo Snellio, e al De Dominis la teoria dell'arco baleno. </s></p><p type="main">

<s>Meglio che al manoscritto dello Snellio, come fu primo a in&shy;<lb/>sinuare l'Huyghens, il quale per&ograve;, a riscontrare il fatto sulle pagine <lb/>dello stesso manoscritto fu secondo dopo Isacco Vossio; noi credia&shy;<lb/>mo che il Cartesio attingesse piuttosto a un libro stampato, qual'&egrave; <lb/>il Corso matematico di Pietro Herigonio. </s>

<s>Perci&ograve;, non &egrave; merito del&shy;<lb/>l'Autore della Diottrica nemmeno l'aver formulata, come l'Huyghens <lb/>e il Newton par che gli concedano, quella legge della proporzione <lb/>costante fra i seni degli angoli incidenti e dei rifratti: n&egrave; suoi pure, <lb/>ma del Keplero, ne sono i principii dimostrativi. </s></p><p type="main">

<s>Quanto all'iride, il Newton che nelle Lezioni di Ottica s'era <lb/>contentato di dire essere stata dal Cartesio, a spiegare il fenomeno, <lb/>apparecchiata la via, nel Trattato di Ottica poi dice che fu il De <lb/>Dominis <emph type="italics"/>vir celeberrimus,<emph.end type="italics"/> il quale prima insegn&ograve; che l'iride inte&shy;<lb/>riore si fa per due rifrazioni e una riflessione e l'esteriore per due <lb/>rifrazioni e due riflessioni. </s>

<s>Or, per amore alla verit&agrave;, convien dire <lb/>che questo &egrave; falso, e siam costretti a concludere che il Newton o <pb xlink:href="020/01/172.jpg" pagenum="153"/>non vedesse o non esaminasse bene il Trattato <emph type="italics"/>De radiis visus et <lb/>lucis<emph.end type="italics"/> del celebre spalatrese. </s>

<s>&Egrave; chiaro infatti che le doppie rifrazioni <lb/>e le doppie riflessioni del De Dominis hanno tutt'altro significato <lb/>che nel Cartesio, e se queste son conformi alla verit&agrave;, quelle son <lb/>delle solite peripatetiche immaginazioni. </s>

<s>N&egrave; affatto giusta sembra <lb/>a noi quell'altra sentenza del Newton che cio&egrave; il Cartesio non in&shy;<lb/>tendesse la natura dei colori, avendo egli rassomigliati i colori del&shy;<lb/>l'iride a quelli in che si disperdono i raggi del sole refratti attra&shy;<lb/>verso ai prismi triangolari. </s></p><p type="main">

<s>Se qualcuno perci&ograve; preced&egrave; il Cartesio nella scientifica spie&shy;<lb/>gazione del fenomeno meteorologico, questi fu, n&ograve; il De Dominis <lb/>ma Ferrante Imperato. </s>

<s>E perch&egrave; non &egrave; facile che il lontano e su&shy;<lb/>perbo Bretone si piegasse a leggere l'Historia Naturale del nostro <lb/>Napoletano, non resta ad ammettere se non che egli attingesse, <lb/>come da prima fonte, al Maurolico citato dallo stesso Cartesio con <lb/>orgoglioso disprezzo. </s></p><p type="main">

<s>Or il Maurolico, che fra tutti i precursori del Newton fu primo <lb/>a intraveder la teoria dei colori e a trattar dell'iride come d'un <lb/>fenomeno d'ottica matematica, bastava solo ad aprir la via al Car&shy;<lb/>tesio, a cui, prevenuto gi&agrave; nell'esperienza delle palle piene d'acqua <lb/>che appariscono iridescenti collocate, rispetto all'occhio, in deter&shy;<lb/>minata posizione e distanza; non bisogn&ograve;, a risolvere il problema, <lb/>altro pi&ugrave; che l'uso del calcolo e della geometria. </s></p><p type="main">

<s>Qui poi, cio&egrave; nel calcolo geometrico consistono i meriti singo&shy;<lb/>lari del Cartesio, il quale ci rivela anco da questa parte lo spirito <lb/>aristotelico informatore della sua nuova Filosofia. </s>

<s>Si vide infatti che <lb/>unico frutto della scuola peripatetica non fu che l'algebra, come <lb/>l'algebra applicata fu pure l'unico frutto della scuola cartesiana. </s>

<s><lb/>Questa stessa applicazione dell'Algebra alla Geometria rende la ra&shy;<lb/>gione di qualcuno di quei progressi, che lo stesso Cartesio fece nella <lb/>Meccanica, bench&egrave; anco di qui trasudi la pece aristotelica in quelle <lb/>sofistiche sottigliezze, tese qua e l&agrave;, per le sue Lettere, come lacci <lb/>insidiosi, a cogliere in fallo i teoremi di Galileo. </s></p><p type="main">

<s>Ma della sterilit&agrave; d'ogni buon frutto di scienza sperimentale il <lb/>Cartesio da s&egrave; stesso s'accusa e si confessa. </s>

<s>S'accusa, quando, nella <lb/>Prefazione alla traduzione latina dei Principii della Filosofia, dice <lb/>che gli resterebbe a trattar della Medicina e delle arti meccaniche, <lb/>per le quali si richiedono sperimenti e spese <emph type="italics"/>quibus privatus qualis <lb/>ego sum nisi a publico adiuvaretur par esse non posset.<emph.end type="italics"/> Galileo, <lb/>che fu tanto pi&ugrave; povero di lui, non fece mai di queste scuse, e si <pb xlink:href="020/01/173.jpg" pagenum="154"/>liber&ograve; dalle spese, che occorrono a sperimentare, fabbricando gli <lb/>strumenti colle sue proprie mani. </s></p><p type="main">

<s>Il Cartesio altres&igrave; da se stesso si confessa, quando in sulla fine <lb/>della sua celebre Dissertazione del Metodo, dop'avere accennato <lb/>alle dottrine fisiche professate ed esposte nella Diottrica e nella <lb/>Meteorologia, soggiunge queste parole: &ldquo; Nec me etiam primum <lb/>ullarum inventorem esse iacto, sed tantum me nunquam illas pro <lb/>meis adoptasse, vel quod ab aliis prius receptae fuissent, vel quod <lb/>non fuissent, verum unicam hanc ob causam quod mihi eas ratio <lb/>persuasisset &rdquo; (Francof. </s>

<s>1692, pag. </s>

<s>40). E cos&igrave; intende forse di sde&shy;<lb/>bitarsi col Maurolico e col Keplero, col De Dominis e con lo Snellio. </s></p><p type="main">

<s>Ma come si conciliano cos&igrave; fatte confessioni colle orgogliose <lb/>pretese del Cartesio? </s>

<s>Una tal domanda non pu&ograve; mover che da co&shy;<lb/>loro, i quali si persuadono che l'Autore della Dissertazione del Me&shy;<lb/>todo dasse qualche importanza alla spiegazione di un particolar fatto <lb/>di Ottica o di Meleorologia. </s>

<s>Queste non son per lui altro che miche <lb/>cadute gi&ugrave; da pi&ugrave; lauta mensa. </s>

<s>Miche son tutte quelle raccattale <lb/>ne'suoi libri da Galileo, e fra quelle stesse miche, dalla teoria della <lb/>musica in fuori, non ci &egrave; nulla di buono. </s>

<s>Che se tu vuoi sedere <lb/>al convito della scienza, par che egli dica al lettore, cerca il mio <lb/>libro che s'intitola <emph type="italics"/>Principii della Filosofia.<emph.end type="italics"/> Vedrai come dalle co&shy;<lb/>gitazioni del lilosofo, nella prima parte dello stesso libro, esca fuori <lb/>l'esistenza di Dio e del mondo. </s>

<s>Vedrai, nella terza parte, come, per <lb/>mezzo di moti vertiginosi, si stabiliscan le leggi che governano <lb/>l'Universo, e nell'ultima di quelle parti assisterai da te stesso al <lb/>nascere e al trasformarsi il seno della tua madre Terra. </s></p><p type="main">

<s>Quando si pubblic&ograve; il Cosmoleoro dell'Huyghens e il Newton <lb/>dimostr&ograve; della Filosofia naturale pi&ugrave; veri Principii, disparvero quei <lb/>seducenti fantasmi cartesiani dagli occhi di tutti. </s>

<s>E che ci rimase <lb/>di realt&agrave;? </s>

<s>Ci rimase l'Algebra geometrica e i due Trattati <emph type="italics"/>Passiones <lb/>animae<emph.end type="italics"/> e <emph type="italics"/>De homine,<emph.end type="italics"/> dove s'instituisce l'interiore esame della <lb/>coscienza, e i fatti psicologici s'illustrano colle matematiche e colla <lb/>fisiologia. </s>

<s>Ecco quel che di scienza vera rimane al Cartesio e alla <lb/>Francia. </s>

<s>Tutto il resto vi approd&ograve; d'Italia, come frutto di quell'al&shy;<lb/>bero che unico seppe metter le radici nel buon terreno, e che ri&shy;<lb/>mase perci&ograve; unico a regnare in mezzo alla foresta. </s></p><p type="main">

<s>Mentre la patria insomma, lusingata dal seducente linguaggio <lb/>e dalle belle promesse, s'aspettava di riposare all'ombra, e sten&shy;<lb/>dendo la mano ai rami dell'amata indigena pianta, largamente <lb/>saziar la fame della scienza, si trov&ograve; a mendicare altri frutti ma-<pb xlink:href="020/01/174.jpg" pagenum="155"/>turati sotto altro sole in terra straniera. </s>

<s>Per men vergogna, e quasi <lb/>che alla mendicit&agrave; si volesse attribuire qualche parte del merito, <lb/>il pietoso ufficio fu commesso a due uomini, i quali partecipavano <lb/>delle due patrie: Niccol&ograve; Fabrizi di Peiresc ed Elia Diodati. </s>

<s>Nati <lb/>ambedue di stirpe Toscana, dalla Toscana trapiantarono in Francia <lb/>la scienza, come i loro avi vi avevano gi&agrave; trapiantata la famiglia, <lb/>e per loro mezzo principalmente risuon&ograve; in fin l&agrave; il nome di Ga&shy;<lb/>lileo, e vi si diffusero le dottrine. </s>

<s>Ismaele Bullialdo ne illustrava <lb/>le dottrine astronomiche e Pier Gassendo le meccaniche. </s>

<s>La fisica <lb/>sperimentale, anch'essa dal Cartesio antivacuista resa impotente, <lb/>fu introdotta in Francia da Marino Mersenno, l'insetto volante, che <lb/>port&ograve; d'Italia sull'ali il polline fecondatore. </s></p><p type="main">

<s>Qual pi&ugrave; piena conquista, qual pi&ugrave; larga vittoria si poteva ri&shy;<lb/>promettere il nostro grande Italiano? </s>

<s>Quell'orgoglioso Bretone, che, <lb/>per libidine di regnar solo, intendeva non tanto di trucidare i fra&shy;<lb/>telli, ma disperdere per fino ogni memoria degli avi, rimase tru&shy;<lb/>cidato anch'esso, non dalla punta, ma dall'ombra della spada di <lb/>Galileo, il cui Regno unico dura, e i discendenti del quale son come <lb/>terribile oste ordinata in battaglia contro l'errore. </s></p><p type="main">

<s>Sarebbe ora il tempo per noi di passare in rivista quei com&shy;<lb/>battenti sotto un unica insegna, se non ci attraessero a s&egrave; gli sguardi <lb/>due ombre solitarie, che avvolte nel pallio filosofale procedono con <lb/>regal maest&agrave; indipendenti. </s>

<s>Come mai, in mezzo alla strage otto&shy;<lb/>manna de'due fieri conquistatori, essi soli son rimasti superstiti, <lb/>quasi fossero giudicati i soli meritevoli di compartecipare alle glorie <lb/>del Regno? </s>

<s>Sono essi Guglielmo Gilbert, e Guglielmo Harvey, sui <lb/>quali due, per conoscerli meglio, convien tener alquanto fisso lo <lb/>sguardo. </s></p><p type="main">

<s>Fruga senza dubbio la nostra curiosit&agrave; il veder che Galileo, <lb/>unico fra i contemporanei, accoglie il Gilbert e l'esalta quasi alla <lb/>dignit&agrave; dei Filosofi antichi. </s>

<s>N&egrave; con minore curiosit&agrave; pure si osserva <lb/>che il Cartesio, nel Gilbert e nell'Harvey, come nelle due sole im&shy;<lb/>mobili torri, abbia fiaccato il vento desolatore della sua superbia. </s>

<s><lb/>Ci&ograve; vuol dire esser grandi davvero, se come tali furon sentiti e <lb/>temuti da quei due che volevano sovraneggiare su tutti; ond'ei non <lb/>&egrave; fuor di proposito l'investigar qui brevemente, di quella grandezza <lb/>che esce cos&igrave; fuori dell'ordinario, la ragione e i meriti. </s></p><p type="main">

<s>N&egrave; in ordine a ci&ograve; &egrave; da lasciar di notare per prima cosa che <lb/>i due grandi Inglesi si distinguono per due qualit&agrave; diverse; l'uno <lb/>dedito principalmente all'esperienza, l'altro alla speculazione. </s>

<s>Il <pb xlink:href="020/01/175.jpg" pagenum="156"/>libro <emph type="italics"/>De magnete<emph.end type="italics"/> &egrave; una sequela di fisici sperimenti, senza dubbio <lb/>avvedutissimi e nuovi, ma che tutti si aggirano intorno al medesimo <lb/>soggetto, con una certa prol&igrave;ssit&agrave;, non forse ingiustamente notata <lb/>dal Verulamio. </s>

<s>Di speculazioni veramente non ha il Gilbert altro <lb/>che quel concetto lodato da Galileo, e qualificato per istupendo, di <lb/>riguardar cio&egrave; la Terra come un magnete e il magnete stesso come <lb/>una terrella. </s>

<s>Del resto egli rifugge dall'approvar que'fluidi magne&shy;<lb/>tici introdotti dal Sarpi e dal Porta, e gli piace meglio di dar, con <lb/>l'antico Talete e con lo Scaligero, alla calamita spirito di vita e <lb/>senso animale. </s></p><p type="main">

<s>L'esercitazione anatomica <emph type="italics"/>De motu cordis<emph.end type="italics"/> dell'Harvey &egrave; al <lb/>contrario tutta una speculazione. </s>

<s>Non &egrave; egli mica che dimostri spe&shy;<lb/>rimentalmente il moto del sangue nel circolo universale dei vasi. </s>

<s><lb/>Egli lo induce principalmente dall'anatomia delle arterie e dalle <lb/>valvole delle vene. </s>

<s>Del resto, egli non sa se veramente il sangue <lb/>arterioso ritorni nelle vene per anastomosi, o perch&egrave; le vene stesse <lb/>lo risorbono disperso e ristagnante in mezzo alle fibre muscolari. </s>

<s><lb/>L'esperienza stessa proposta da Galeno a lui pare impossibile d'ese&shy;<lb/>guirla negli animali vivi. </s>

<s>Non gli par che possa riuscire a nessuno <lb/>d'introdurre un cannellino di materia trasparente nelle due imboc&shy;<lb/>cature dell'arteria recisa, e ci&ograve; per la gran violenza del sangue <lb/>che irrompe. </s>

<s>Eppure il nostro Tommaso Cornelio dimostr&ograve;, contro <lb/>l'Harveio, che l'esperienza di Galeno si poteva benissimo praticare, <lb/>e, negli animali vivi, por, sotto gli occhi de'riguardanti stupiti, il <lb/>sangue che fugge espulso dalla sistole del cuore. </s></p><p type="main">

<s>L'altro libro non men celebre dell'Harvey &egrave; quello <emph type="italics"/>De gene&shy;<lb/>ratione animalium.<emph.end type="italics"/> Si disse che per lui f&ugrave; finalmente cacciato quel <lb/>pernicioso errore della generazione spontanea. </s>

<s>Chi vi torna sopra <lb/>per&ograve; con pi&ugrave; maturo giudizio, &egrave; costretto a concludere che il gran <lb/>Filosofo inglese niente altro fa che sostituire a un errore, un errore <lb/>pi&ugrave; vieto. </s>

<s>Egli ammette infatti nella materia certi principii animali, <lb/>predisposti dall'Artefice eterno, nella primitiva creazion delle cose: <lb/>principii che l'Elmont chiam&ograve; col nome di <emph type="italics"/>archei,<emph.end type="italics"/> e l'Harveio, con <lb/>fedel traduzione, primordii. </s>

<s>Da cos&igrave; fatti principii disseminati qua <lb/>e l&agrave; per l'aria e caduti per caso in parte dove trovassero favore&shy;<lb/>voli condizioni al loro incubamento, avrebbero, secondo l'Autore, <lb/>origine tutti quegl'insetti, che non riconoscono un padre. </s>

<s>Ma a di&shy;<lb/>mostrar che veramente ogni animale, sia pure di qualunque infimo <lb/>ordine, riconosce un padre e una madre della medesima specie, vi <lb/>bisognavano quelle attente e pazientemente ripetute esperienze, alle <pb xlink:href="020/01/176.jpg" pagenum="157"/>quali si credeva l'Harvey di poter supplir con le ipotesi e con le <lb/>induzioni: esperienze che poi riuscirono cos&igrave; bene alle mani del <lb/>Redi e del Malpighi. </s></p><p type="main">

<s>In ogni modo, il Gilbert e l'Harvey sono due ingegni singo&shy;<lb/>lari: il primo &egrave; mirabile per l'arte squisitissima di sperimentare e <lb/>l'altro per una potentissima virt&ugrave; d'indurre la verit&agrave; dai fatti sem&shy;<lb/>plicemente osservati. </s>

<s>Se avessero avuta comune la potenza dell'in&shy;<lb/>gegno, com'ebbero comune la patria, d'ambedue loro insieme sa&shy;<lb/>rebbe uscita al mondo una cosa perfetta. </s></p><p type="main">

<s>Or su quale albero mai &egrave; maturata quella tal perfezione? </s>

<s>Sul&shy;<lb/>l'albero vecchio, rispondasi, della scienza italiana. </s>

<s>Chi legge la Fi&shy;<lb/>siologia Nuova del Magnete non ha bisogno di tanti argomenti a <lb/>persuadersi che il Gilbert non attinge d'altronde le prime tradi&shy;<lb/>zioni della scienza magnetica che dall'Italia; dal Fracastoro, dal <lb/>Sarpi, dal Porta. </s>

<s>Chi legge l'Esercitazione anatomica <emph type="italics"/>De motu cordis<emph.end type="italics"/><lb/>non ha bisogno di far tante domande: risponde da s&egrave; medesimo <lb/>l'Autore, pi&ugrave; coi fatti che con le parole, esser quello il frutto elet&shy;<lb/>tissimo degli insegnamenti padovani. </s></p><p type="main">

<s>Consolati dall'ammirar tali due frutti che insaporarono sotto i <lb/>soli d'Italia, sopra i pi&ugrave; sporgenti rami del vecchio albero della <lb/>scienza, ora &egrave; tempo di venire una volta a veder quai rigogliosi <lb/>rampolli, e quale ubert&agrave; di frutti si producessero nell'albero nuovo. </s></p><p type="main">

<s><emph type="center"/>V.<emph.end type="center"/></s></p><p type="main">

<s>Il primo e pi&ugrave; eletto di quei rampolli, &egrave; il bresciano don Be&shy;<lb/>nedetto Castelli. </s>

<s>Come nella generazione animale il primogenito <lb/>suol, meglio degli altri parti, rassomigliar le virt&ugrave; e le fattezze stesse <lb/>del padre; cos&igrave; nelle opere dell'ingegno il Castelli ha pi&ugrave; strette <lb/>le somiglianze con Galileo. </s>

<s>L'Autore dei Dialoghi del moto, pot&egrave; <lb/>con diritto intitolar quell'opera <emph type="italics"/>Scienza Nuova,<emph.end type="italics"/> e Scienza Nuova, <lb/>con pari diritto, poteva intitolare i suoi libri l'Autore della Misura <lb/>delle acque correnti. </s>

<s>N&egrave; l'esser preceduto dall'Alberti e dal Cardano <lb/>o dal pi&ugrave; antico Frontino gli toglie nulla a quella novit&agrave;, o gli detrae <lb/>del suo principato, se per poco si ripensi che non consiste la scienza <lb/>in alcune pratiche cognizioni, ma nell'ordinata sequela di teoremi <lb/>dimostrati e conclusi da veri e approvati principii. </s>

<s>Non gli detrae <pb xlink:href="020/01/177.jpg" pagenum="158"/>nulla Leonardo da Vinci, le speculazioni e l'esperienze del quale <lb/>rimanevano tuttavia informi e sepolte nei manoscritti. </s>

<s>In ogni modo, <lb/>gli errori che si commettevano nelle dispense delle acque in Lom&shy;<lb/>bardia, con s&igrave; grave danno ora dei compratori, ora dei venditori, <lb/>attestano che a quei tempi nessuno ancora gli aveva notati, e se <lb/>tanto zelo bisogn&ograve; al Castelli per persuader quelle verit&agrave; negli usi <lb/>inveterati, &egrave; ci&ograve; manifestissimo segno dell'apparir nuove fra gli <lb/>uomini le verit&agrave; stesse predicate da lui. </s>

<s>Nuove, non che ad altri, <lb/>apparvero al medesimo Galileo, come, per citare un fatto solo, po&shy;<lb/>trebbesi argomentar facilmente comparando il Discorso contro il <lb/>Bertazzolo, con la Lettera sul fiume Bisenzio. </s></p><p type="main">

<s>Altro punto di rassomiglianza, che il Castelli ha con Lui che <lb/>lo aveva generato alla scienza, &egrave; l'ardor di diffondere quelle astro&shy;<lb/>nomiche verit&agrave;, che un profondo sentimento sincero di Religione <lb/>gli persuadeva esser tanto meglio adattate degli antichi sistemi a <lb/>rivelar le glorie del Creatore. </s>

<s>Nelle fasi di Venere, prima che Ga&shy;<lb/>lileo gli avesse palesati i suoi pensieri, nei moti di alcune stelle, che <lb/>ei dubita esser effetti della parallasse annuale, sagacemente intra&shy;<lb/>vede argomenti concludenti<gap/>simi a confermare la verit&agrave; del sistema <lb/>copernicano. </s>

<s>Nel piccolo mondo gioviale riconosce perfettamente <lb/>ritratta l'immagine del pi&ugrave; gran mondo solare, e nelle quattro lune <lb/>che si rivolgono intorno al centro di Giove, gli par avere il pi&ugrave; <lb/>bello argomento a provar che i pianeti si rivolgono in simil modo <lb/>intorno al centro del sole. </s>

<s>Egli, pi&ugrave; infaticabile forse di quel che <lb/>non apparisce dai pochi documenti rimasti, a calcolar l'Effemeridi <lb/>dei quattro satelliti cooperava con Galileo, che di quando in quando <lb/>nota ne'suoi Registri, che l'osservazione fatta, per quel tal giorno <lb/>e per quell'ora, &egrave; <emph type="italics"/>Patris Benedicti.<emph.end type="italics"/> E quando il Cassini attendeva <lb/>all'Effemeridi bolognesi, il Viviani, perch&egrave; se ne potesse giovare, <lb/>e perch&egrave; le riscontrasse con le sue nuove osservazioni, gli mandava <lb/>una tavola dei moti de'Medicei, incerto se essa apparteneva a Ga&shy;<lb/>lileo o al Castelli. </s></p><p type="main">

<s>N&egrave; da passare inconsiderata, a proposito delle esercitazioni <lb/>astronomiche del p. </s>

<s>Benedetto, &egrave; la prima osservazione di quella <lb/>fascia, che precinge il corpo di Giove, con quell'altra, che concerne <lb/>la luce secondaria, di che va suffusa la Luna vicina al primo quarto. </s>

<s><lb/>Dice che, facendo egli riflessione a quel che Galileo ne'Dialoghi del <lb/>Sistema accenna della medesima luce secondaria, pi&ugrave; cospicua la <lb/>mattina che la sera, adducendone per ragione l'essere in quel tempo <lb/>la Luna illuminata dal riflesso di vastissimi continenti della Terra; <pb xlink:href="020/01/178.jpg" pagenum="159"/>giudic&ograve; che ritrovandosi, in quel tempo che faceva le sue osserva&shy;<lb/>zioni, la Luna meridionale, dovesse essere illustrata dalla Terra, e <lb/>perci&ograve; gli venne in mente che le terre meridionali, allora incognite, <lb/>dovessero essere vastissime provincie (Alb. </s>

<s>X, 244). Galileo approv&ograve; <lb/>la congettura (ivi, pag. </s>

<s>248), e le scoperte geografiche avverarono <lb/>il vaticinio. </s></p><p type="main">

<s>Educatosi alla lettura del Saggiatore, che, spiegava come testo <lb/>di Fisica nuova nella sua scuola, il Castelli scrisse, in soggetto di <lb/>fisica sperimentale, alcuni Trattatelli o Discorsi, amorosamente rac&shy;<lb/>colti o fatti pubblicare nel 1669 dal principe Leopoldo dei Medici, <lb/>venticinque anni dopo la morte dell'Autore. </s>

<s>Quello <emph type="italics"/>Sulla vista<emph.end type="italics"/> non <lb/>&egrave; per verit&agrave; che un commentario delle dottrine ottiche del Keplero. </s>

<s><lb/>In quello che egli intitola <emph type="italics"/>Mattonata<emph.end type="italics"/> si descrivono le prime espe&shy;<lb/>rienze e si tentano le prime teorie del calorico raggiante, e in <lb/>quell'altro <emph type="italics"/>Del modo di conservare i grani<emph.end type="italics"/> si notano per la prima <lb/>volta i varii gradi di conducibilit&agrave; del calore nelle varie costituzioni <lb/>dei corpi. </s>

<s>Il <emph type="italics"/>Discorso sulla Calamila,<emph.end type="italics"/> pubblicato in questi ultimi <lb/>anni, non ha, a voler esser giusti, di che la scienza del Magnete <lb/>s'avvantaggi. </s></p><p type="main">

<s>Immediatamente dopo il Castelli, si dovrebbe collocare, in questo <lb/>splendido Senato della scienza italiana, Bonaventura Cavalieri, se, <lb/>piuttosto che alle scienze sperimentali, non avesse atteso alla Ma&shy;<lb/>tematica pura e alla Geometria, nelle quali discipline fece cos&igrave; <lb/>grandi progressi, da meritarsi che Galileo lo onorasse pubblicamente <lb/>asserendo di lui ch'ei sarebbe per riuscire uno de'principali ma&shy;<lb/>tematici di quei tempi (Alb. </s>

<s>XIII, 45). Dallo sperimentare il Cava&shy;<lb/>lieri non &egrave; alieno, ma non ha, o non sa trovare il modo d'eserci&shy;<lb/>tarvisi. </s>

<s>Si prova a disegnar qualche macchina, ma nell'effetto non <lb/>riesce. </s>

<s>Proposto dal Torricelli al Granduca per uno degli arbitri a <lb/>decidere le famose controversie del regolamento delle Chiane, se <lb/>ne scusa, rispondendo che a lui <emph type="italics"/>mancava quella esperienza che <lb/>bisogneria ancora aver fatto per poter parlar francamente in simil <lb/>materia<emph.end type="italics"/> (MSS. Gal. </s>

<s>Disc. </s>

<s>T. XLI, c. </s>

<s>223). Nonostante a lui si deb&shy;<lb/>bono alcuni utili avvertimenti intorno alle figure geometriche da <lb/>darsi ai vetri, per uso dei canocchiali, e fu il primo che pubbli&shy;<lb/>casse, nel suo <emph type="italics"/>Specchio Ustorio,<emph.end type="italics"/> il pensiero sovvenutogli di com&shy;<lb/>porre insieme, negli strumenti astronomici, le lenti cristalline e gli <lb/>specchi. </s>

<s>Richiestone dal Castelli, egli fu che distese la famosa Di&shy;<lb/>mostrazione della proposizione II, inserita dal suo stesso Autore. </s>

<s><lb/>senza mutar parola, nel II Libro della Misura delle Acque correnti. <pb xlink:href="020/01/179.jpg" pagenum="160"/>Egli fu che di splendidi e nuovi concetti illustr&ograve; la dimostrazione <lb/>galileiana delle leggi dei moti naturali e dei proietti. </s></p><p type="main">

<s>Alla fama, che &egrave; certa di non essere smentita, alla fede che <lb/>s'alimenta d'affetto, alla morte che fa l'uomo credulo e piamente <lb/>indulgente, piuttosto che alle opere scritte e stampate, va debitore <lb/>d'essere annoverato qui in terzo luogo, Vincenzio Renieri. </s>

<s>Nel tempo <lb/>che il negoziato delle Longitudini con gli Stati Uniti di Olanda sol&shy;<lb/>lecitava Galileo di dar compiuto ordine alle Effemeridi gioviali, il <lb/>Renieri pensava a stampar le sue <emph type="italics"/>Tabulae Secundorum mobilium,<emph.end type="italics"/><lb/>che il Cavalieri giudic&ograve; degne di essere dagli studiosi dell'Astro&shy;<lb/>nomia annoverate fra.i libri di maggiore utilit&agrave; (Alb. </s>

<s>X, 398). Della <lb/>stampa ne trattava l'Autore, nel marzo del 1637, con Galileo, pre&shy;<lb/>gandolo volesse scrivere a Roma due righe al Castelli, perch&egrave; si <lb/>prendesse cura di muovere parola allo stampatore Guglielmo Fa&shy;<lb/>ciotti (ivi, pag. </s>

<s>200). Le trattative andarono per&ograve; a vuoto, e le Tavole <lb/>dei Secondi Mobili, intitolate Medicee, perch&egrave; dedicale al Granduca <lb/>Ferdinando II, si stamparono in Firenze nel 1639. Largamente poi <lb/>ampliate e corrette, quelle stesse Tavole, furono nuovamente im&shy;<lb/>presse dal medesimo stampatore nel 1647. Pregato il Torricelli di <lb/>riveder le bozze di stampa, in sul punto che doveva incoglierlo la <lb/>morte, suppl&igrave; al tedioso ufficio il Viviani (MSS. Gal.Dis. </s>

<s>T. CXLIV, c.4). </s></p><p type="main">

<s>Tornando ora indietro al 1637, Galileo, che sollecitato dal ne&shy;<lb/>gozio delle Longitudini si sentiva, per la vecchiezza e per la cecit&agrave;, <lb/>a cos&igrave; faticosa opera impotente, pens&ograve; di chieder l'aiuto del Renieri, <lb/>riconosciuto per i calcoli delle Tavole Medicee, il pi&ugrave; esperto fra i <lb/>suoi Discepoli. </s>

<s>Il Renieri, dall'altra parte, con lettera del d&igrave; 11 Di&shy;<lb/>cembre 1637, rispose che non avrebbe tralasciato cura o diligenza <lb/>alcuna possibile per servirlo (Alb. </s>

<s>X, 247). </s></p><p type="main">

<s>Preordinate cos&igrave; le cose, Galileo incominci&ograve; col padre Vincenzio <lb/>una specie d'istituzione intorno alle operazioni astronomiche ne&shy;<lb/>cessarie a perfezionare i calcoli delle Medicee, e per prima gli in&shy;<lb/>segna la sua invenzione del misurare il foro della pupilla. </s>

<s>Poi torna <lb/>a descrivergli l'uso dello strumento per misurarne pi&ugrave; esattamente <lb/>le distanze dei pianeti dal centro di Giove, e gli consegna, perch&egrave; <lb/>gli possano servire di norma, le Effemeridi calcolate gi&agrave; da s&egrave; e <lb/>dal Castelli. </s>

<s>Nell'Aprile del 1639 l'Osservatore di Genova scrive a <lb/>Galileo poco mancargli per avere emendato in tutto il moto delle <lb/>Medicee, e per rendere assolute l'Effemeridi di sei mesi futuri <lb/>(Alb. </s>

<s>X, 336). Nel maggio ammalato, tornato nel giugno al faticoso <lb/>lavoro, s'accorse che, ad emendar que'moti, all'equazion tolemaica <pb xlink:href="020/01/180.jpg" pagenum="161"/>dei giorni naturali conveniva aggiungervene in ogni modo un'altra, <lb/><emph type="italics"/>cagionata dal mancar la velocit&agrave; del moto diurno nell'allontanarsi <lb/>la Terra dal sole apogeo<emph.end type="italics"/> (ivi, pag. </s>

<s>339). </s></p><p type="main">

<s>Proseguiva il valente osservatore, con grande alacrit&agrave; nell'im&shy;<lb/>presa, tanto pi&ugrave; ch'ei ci vedeva infervorati il Granduca e il Prin&shy;<lb/>cipe Leopoldo, che lo fornivano de'pi&ugrave; eccellenti canocchiali, che <lb/>si sapesse essere stati fabbricati in Europa. </s>

<s>Perci&ograve;, alla corte di <lb/>Firenze, il Renieri mandava l'Effemeridi calcolate via via, prima <lb/>che ad Arcetri. </s>

<s>Il principe Leopoldo per&ograve; ne faceva riscontrar l'esat&shy;<lb/>tezza, e avute quelle per l'aprile e pel maggio 1640, nelle notti del <lb/>due e degli otto di quel medesimo mese di Maggio, furono osservati <lb/>tre satelliti sempre occidentali e uno orientale. </s>

<s>&ldquo; Ora avendosi dal&shy;<lb/>l'Effemeridi (scrive lo stesso Principe al Renieri) che in tal notte <lb/>si dovevano vedere due di quelle stelle orientali e due occidentali, <lb/>mi fa venir dubbio che una tanta differenza, quale non pu&ograve; nascere, <lb/>n&egrave; per lo svariar degli orioli n&egrave; per negligenza dell'osservatore, <lb/>possa venire dall'errore della stampa &rdquo; (MSS. Gal. </s>

<s>Dis. </s>

<s>T. V. c. </s>

<s>248). </s></p><p type="main">

<s>Par che dunque fossero quelle Effemeridi stampate, e cos&igrave; forse <lb/>l'Autore intendeva di mettere insieme a poco per volta il suo libro. </s>

<s><lb/>Ma in sette anni, quanti ne decorsero dalla data di questa lettera, <lb/>che &egrave; del 13 maggio 1640, alla morte dell'Autore, la pubblicazione <lb/>di quelle Tavole di tanti desiderii, non solo non ebbe effetto, ma <lb/>nessuno sa dir se nemmeno ella avesse avuto principio. </s>

<s>Ragione di <lb/>una tale incertezza &egrave; il celebre fatto della dispersione delle carte <lb/>e degli strumenti astronomici del Renieri, immediatamente avve&shy;<lb/>nuta dopo la morte di lui. </s>

<s>Celebre fatto diciamo, per le tante cose <lb/>che da tanti ne sono scritte. </s>

<s>A noi basta richiamar l'attenzione <lb/>sopra una lettera, che, pochi giorni dopo la morte del fratello, scri&shy;<lb/>veva a uno sconosciuto cortigiano de'Medici Giovan Battista Renieri. <lb/></s>

<s>&ldquo; Vivo in speranza, egli dice, circa la ricuperazione delli scritti <lb/>della felice memoria di mio fratello: ne attendo pertanto l'avviso <lb/>dell'effetto, avendo intenzione di pubblicare alle stampe l'opera che <lb/>egli ha composto del moto de'pianeti medicei di Giove. </s>

<s>E perch&egrave; <lb/>forse l'immatura sua morte gli ha tronco que'concetti, che sperava <lb/>col tempo di produrre alla luce, desidererei pertanto, avendomeli <lb/>in sua vita partecipati, farli pubblicare sotto il suo nome &rdquo; (MSS. Gal. </s>

<s><lb/>Disc. </s>

<s>T. V. c. </s>

<s>232). Da chi Giovan Battista sperasse di recuperare <lb/>quei manoscritti, non si sa, perch&egrave; non lo dice. </s>

<s>Forse potrebb'esser <lb/>quel Giuseppe Agostini, su cui fecero cadere un sospetto di furto <lb/>Cosimo Galilei e il Viviani. </s>

<s>In ogni modo per&ograve;, n&egrave; Giovan Batista <pb xlink:href="020/01/181.jpg" pagenum="162"/>Renieri, n&egrave; Cosimo Galilei riuscirono a recuperare le carte del fra&shy;<lb/>tello e dell'avo. </s>

<s>Che le venissero poi da Pisa alla Biblioteca pala&shy;<lb/>tina di Firenze, non si sa per&ograve; come n&egrave; quando, lo afferma l'Alberi; <lb/>e se delle Effemeridi e degli altri studii intorno al sistema di Giove <lb/>non si trovarono veramente, fra le carte del Monaco olivetano, altro <lb/>che le cose pubblicate dal medesimo Alb&egrave;ri, si pu&ograve; ripetere quel <lb/>che si diceva dianzi, che cio&egrave; la gloria scientifica di Vincenzio Re&shy;<lb/>nieri &egrave; affidata alla fama, alla fede, a quella riverenza che inspira <lb/>la morte. </s></p><p type="main">

<s>Men famoso nei posteri e men fortunato, perch&egrave; nell'opere <lb/>pubblicamente note pot&egrave; la censura esercitare il suo dente, fu don <lb/>Famiano Michelini, una strana figura di uomo, che sognando di <lb/>chiappar milioni con le sue scoperte, mor&igrave; nel 1666, vecchio di 73 <lb/>anni, nell'indigenza. </s>

<s>Propugnatore della Medicina statica del Santo&shy;<lb/>rio, perch&egrave; pi&ugrave; volte il giorno, quand'era ancora scolopio sotto il nome <lb/>di fra Francesco da S. Giuseppe, si pesava sulla stadera, per fare <lb/>esperienza in se dell'insensibile traspirazione; i ragazzi lo additavano <lb/>per le vie di Firenze chiamandolo il <emph type="italics"/>Padre Staderone.<emph.end type="italics"/> Spacciando <lb/>nelle bibite limonate il migliore specifico per cacciar la febbre, i <lb/>fiorentini lo proverbiarono con motti arguti, e con epigrammi. </s>

<s>Il <lb/>Cavalieri, confondendo insieme l'abilit&agrave; d'idraulico con quella di <lb/>medico, illuso prima e poi deluso dell'efficacia della ricetta, scriveva <lb/>al Torricelli, a proposito delle Chiane, &ldquo; che la proposta del padre <lb/>Francesco ander&agrave; al pari con l'altra di risanarmi dalla podagra &rdquo; <lb/>(MSS. Gal. </s>

<s>Dis. </s>

<s>T. XL. c. </s>

<s>223) e il Granduca, in ogni modo, non gli <lb/>poteva perdonare l'apostasia dall'ordine calasanziano. </s>

<s>Ci&ograve; nonostante, <lb/>fu eletto ad ammaestrare nelle matematiche il giovanetto principe <lb/>Leopoldo, in cui infuse un grande amore alle scienze sperimentali, <lb/>e gli raffin&ograve; il gusto a sentir quanto fosse di vero nelle nuove dot&shy;<lb/>trine promulgate da Galileo. </s>

<s>Se non avesse altro merito, basterebbe <lb/>questo per dovere annoverare il Michelini tra i pi&ugrave; validi coope&shy;<lb/>ratori ai progressi della scienza italiana. </s>

<s>Ma egli vi cooper&ograve;, e pi&ugrave; <lb/>efficacemente di quel che non si stimi, con le proprie speculazioni <lb/>e con le proprie esperienze, esposte in iscritti, in cui la bellezza <lb/>del dettato aggiunge splendore all'importanza della materia. </s></p><p type="main">

<s>Il Trattato della <emph type="italics"/>Direzione dei fiumi,<emph.end type="italics"/> co'suoi errori non lievi, <lb/>&egrave; pure il primo che dirige l'opera da praticarsi sui fiumi, con la <lb/>scorta di una scienza, che quasi sempre &egrave; sicura. </s>

<s>Il Viviani, dietro <lb/>quegli insegnamenti, regolava l'Arno con altri fiumi della Toscana, <lb/>e per mezzo di Ottavio Falconieri insegnava a regolar similmente <pb xlink:href="020/01/182.jpg" pagenum="163"/>il Tevere agli ingegneri romani. </s>

<s>Nei Discorsi medici don Famiano <lb/>ha senza dubbio delle stranezze, ma egli &egrave; il primo, co'suoi metodi <lb/>matematici, a cacciar l'empirismo e ad esaltar l'arte medica al <lb/>grado e alla dignit&agrave; di scienza. </s>

<s>Fu dagli insegnamenti di lui che <lb/>ebbe principio la tanto benemerita scuola medica sperimentale isti&shy;<lb/>tuita dal Redi. </s></p><p type="main">

<s>Men noti dei quattro annoverati fin qui, sono altri illustri allievi <lb/>di quella prima scuola galileiana, i quali, dallo scrivere e dal pub&shy;<lb/>blicar gli scritti delle loro speculazioni, o furon divietati da una <lb/>morte immatura, o ne furon distratti dall'attendere a varii altri <lb/>ufficii. </s>

<s>Primo fra questi occorre a commemorare Niccol&ograve; Aggiunti <lb/>che, nato nel 1600, in 35 anni comp&igrave; tutto insieme il corso delle <lb/>scienze e della vita. </s>

<s>Quel che egli speriment&ograve; di fisica o dimostr&ograve; <lb/>di meccanica &egrave; rimasto negli informi manoscritti di lui, chi svolge <lb/>i quali, si sente stringere il cuore da piet&agrave;, che gli impedisse la <lb/>morte di maturare quella cos&igrave; feconda novit&agrave; di pensieri. </s>

<s>Si direbbe, <lb/>a leggere quelle note e quegli appunti rimasti di lui, che Galileo <lb/>infuse nel giovane alunno quegli spiriti latenti, che si manifestarono <lb/>poi nei Dialoghi delle Due Nuove Scienze. </s>

<s>Chi non direbbe infatti <lb/>che quelle proposizioni dimostrate dall'Aggiunti intorno alla ten&shy;<lb/>sione delle corde sonore, non fossero cadute dalla penna di Galileo, <lb/>quando pensava di dar fondamenti matematici all'Acustica? </s>

<s>Le so&shy;<lb/>luzioni di parecchi problemi, che si leggono in questi manoscritti, <lb/>come quello delle condizioni dell'equilibrio di un pezzo di legno, <lb/>in parte campato in aria e in parte sostenuto da un piano, somi&shy;<lb/>gliante a quell'altro, qui pur risoluto, della catena in parte distesa <lb/>su un asse e in parte pendula, rivelano che l'Autore, nella scienza <lb/>del moto, precorreva al Maestro. </s></p><p type="main">

<s>Ma che egli lo precorresse veramente finiscono di persuaderlo <lb/>quei meccanici teoremi, la matematica dimostrazione dei quali non <lb/>par che avesse altro intento, che di supplire al difetto dei Dialoghi <lb/>de'Due Massimi Sistemi. </s>

<s>Galileo infatti, contento ad enunciarli, lascia <lb/>ivi i principali teoremi del moto indimostrati, riserbandosi a farlo <lb/>negli altri Dialoghi, che meditava di scrivere intorno a quel proprio <lb/>soggetto. </s>

<s>Ma intanto l'Aggiunti cerca e ritrova da s&egrave; cos&igrave; fatte di&shy;<lb/>mostrazioni. </s>

<s>Tale &egrave; quella del pendolo, pubblicata nei Saggi di storia <lb/>letteraria dal Nelli (Lucca 1759, pag. </s>

<s>89, 90), tal'&egrave; quella del teore&shy;<lb/>ma, cos&igrave; formulato: &ldquo; La medesima velocit&agrave; nelle maggiori o minori <lb/>quantit&agrave; di materia, opera pi&ugrave; o meno potentemente secondo la <lb/>proporzione di essa materia &rdquo; (MSS. Gal. </s>

<s>Disc. </s>

<s>T. XVIII, c. </s>

<s>95), tale, <pb xlink:href="020/01/183.jpg" pagenum="164"/>per tacere di altre, la dimostrazione della palla perfettamente sfe&shy;<lb/>rica, posata su un piano perfettamente orizzontale, che non tende <lb/>a muoversi pi&ugrave; verso l'una parte che l'altra (ivi, c. </s>

<s>100). </s></p><p type="main">

<s>Che poi l'Aggiunti procedesse, nella dimostrazione di questi <lb/>teoremi galileiani del moto, indipendentemente dalla guida del Mae&shy;<lb/>stro, lo prova quella stessa libert&agrave;, colla quale ne censura alcune <lb/>dottrine. </s>

<s>Esempio ne sia quello delle forze centrifughe, delle quali <lb/>tratta Galileo nel II Dialogo dei Massimi Sistemi (Alb. </s>

<s>I. 213,38). <lb/>Ammesso dall'Aggiunti il principio che &ldquo; acciocch&egrave; un mobile <lb/>acquisti, da virt&ugrave; intrinseca, impeto di muoversi per una tal dire&shy;<lb/>zione, bisogna che il motore l'abbia movendo accompagnato per <lb/>qualche spazio in essa dirittura &rdquo; perciocch&egrave; in un cerchio non ci <lb/>&egrave; dirittura alcuna, conclude: &ldquo; laonde sar&agrave; falso che dalla vertigine <lb/>di una ruota si conferisca alle sue parti impeto di muoversi per la <lb/>tangente, com'asserisce l'eccellentissimo signor Galileo &rdquo; (ivi, c. </s>

<s>59). </s></p><p type="main">

<s>La censura se non &egrave; vera, &egrave; senza dubbio assai arguta, come <lb/>argute sono altre censure, che promuove contro lo stesso Galileo <lb/>rispetto alla teoria de'galleggianti. </s>

<s>Accomodato un parallelepipedo <lb/>nelle condizioni di galleggiamento richieste da Galileo, l'Aggiunti <lb/>cos&igrave; soggiunge: &ldquo; Tutto questo passa bene, secondo la dottrina del <lb/>signor Galileo, se porremo che l'acqua sia solamente da una banda. </s>

<s><lb/>Ma qui mi nascono molte difficolt&agrave;, che fanno contro al Galileo <lb/>ancora, perch&egrave; non pare che basti, acci&ograve; un solido men grave in <lb/>specie dell'acqua, sia alzato, che l'acqua lo bagni da una parte sola, <lb/>e secondo quell'altezza che vuole il Galileo, ma tal sollevamento <lb/>bisogna che sia a mio giudizio d'ogni intorno &rdquo; (ivi, c. </s>

<s>107). Qui <lb/>l'Autore del manoscritto, che nota come la cosa vuol esser pensata <lb/>meglio, ha pi&ugrave; ragione di censurare che dianzi: quelle galileiane <lb/>dottrine son difettose, perch&egrave;, nello spiegar l'effetto de'galleggia&shy;<lb/>menti, s'esclude l'intervento delle pressioni idrostatiche, per cui <lb/>con ragione, l'Aggiunti che non seppe pensar da s&egrave; all'efficacia di <lb/>quelle pressioni, si sentiva aggirar la mente da quei dubbi penosi. </s></p><p type="main">

<s>Ben pi&ugrave; sicuro per&ograve; del fatto suo &egrave; l&agrave; dove, per supplire ai <lb/>difetti di Erone, divisa la nuova teoria del moto delle acque nei <lb/>sifoni ritorti. </s>

<s>Si lagnava il Castelli con Galileo, perch&egrave; l'Aggiunti, <lb/>senza fargliene parola, andava spacciando che nel Discorso Della <lb/>Misura delle Acque correnti ci erano alcuni errori gravi (Campori <lb/>Cartag. </s>

<s>gal. </s>

<s>cit. </s>

<s>pag. </s>

<s>417). Quali fossero gli errori gravi notati dal&shy;<lb/>l'Aggiunti, bench&egrave; il Castelli non si spieghi davvantaggio, si pu&ograve; <lb/>arguir facilmente da queste teorie del sifone eroniano, nel dimostrar <pb xlink:href="020/01/184.jpg" pagenum="165"/>le quali si ammette dall'Autore che le velocit&agrave; nel flusso dell'acqua, <lb/>come nella caduta di tutti gli altri corpi gravi sieno proporzionali <lb/>alle radici delle altezze. </s>

<s>Ora perch&egrave; il Castelli in quel suo Trattato, <lb/>professava il principio che le stesse velocit&agrave; fossero proporzionali <lb/>alle semplici altezze, pu&ograve; esser benissimo che l'Aggiunti spacciasse <lb/>questo per un errore. </s>

<s>Un errore poi lo credette il Torricelli, e i <lb/>seguaci delle teorie di lui, ond'&egrave; che nel proporre quelle nuove <lb/>teorie, l'Aggiunti prevenne di parecchi anni lo stesso Torricelli. </s></p><p type="main">

<s>Fra le molte esperienze di fisica, che si trovano descritte o <lb/>accennate per questi manoscritti, la pi&ugrave; importante, a nostro giu&shy;<lb/>dizio, e la pi&ugrave; nuova &egrave; quella del dilatarsi de'solidi al calore, ci&ograve; <lb/>che egli dimostra in un filo metallico o in un ago, e per cui spiega <lb/>la variet&agrave; de'suoni dati dalle corde degli strumenti, al variare delle <lb/>stagioni. </s>

<s>Notabile &egrave; che gli effetti di quel dilatamento lineare dei <lb/>solidi l'attribuisca all'aria che s'interpone fra i pori di tutti i corpi, <lb/>e pi&ugrave; notabili che mai quei pensieri intorno al vacuo, e alla forza <lb/>necessaria a superarlo, che gli occorrono in tal proposito: pensieri <lb/>che fanno cos&igrave; perfetto riscontro con quelli che, nel primo Dialogo <lb/>delle Due Nuove Scienze, alquanti anni dopo la morte del Nostro, <lb/>rivel&ograve; Galileo. </s>

<s>Che poi l'Aggiunti, dalle speculate esperienze e dalle <lb/>minute osservazioni, sapesse con ardito volo risalire ai principii ge&shy;<lb/>nerali, lo dimostra quella sottile ipotesi del moto occulto dell'acqua, <lb/>con cui spiega e applica gli effetti di capillarit&agrave; a innumerabili e <lb/>inesplicati fatti della Natura. </s>

<s>N&egrave; si pu&ograve; senza gran maraviglia pen&shy;<lb/>sare, che egli spieghi per questo modo il moto del chilo negli ani&shy;<lb/>mali, mentre parecchi anni dopo il gran Pecquet aveva bisogno di <lb/>ricorrere miseramente al moto vermicolare dei vasi, e alla com&shy;<lb/>pressione toracica degli atti respiratorii. </s></p><p type="main">

<s>Dei danni recati all'incremento della scienza dagli inesorabili <lb/>casi della vita, in questa cos&igrave; ristretta cerchia dei primi Discepoli <lb/>di Galileo, due altri esempi abbiamo a deplorare in Cosimo Noferi, <lb/>e in Antonio Nardi. </s>

<s>Per cominciare a parlar del primo, ei lasci&ograve; <lb/>quattro bei volumi manoscritti, di carettere nitido, e ornati, nei <lb/>frontespizi e altrove, di tocchi in penna cos&igrave; ben condotti, da esser <lb/>tenuti in qualche pregio artistico dagl'intendenti. </s>

<s>Son que'volumi <lb/>altrettanti libri divisi ciascuno in Discorsi, che par l'Autore gli leg&shy;<lb/>gesse via via in qualche Accademia fiorentina. </s>

<s>Si discorre princi&shy;<lb/>cipalmente nel I libro dell'ordine di fabbricare le fondamenta, in <lb/>qualsivoglia luogo, dell'ordine delle armature e fabbriche delle volte, <lb/>dell'ordine di diversi cavalletti per le coperte. </s>

<s>Si passa nel II libro <pb xlink:href="020/01/185.jpg" pagenum="166"/>a discorrere dell'ordine e della fabbrica dei ponti murati, dei ponti <lb/>di un solo arco, dei ponti sui fiumi reali. </s></p><p type="main">

<s>Nel III libro, che &egrave; il pi&ugrave; importante per noi, si discorre del <lb/>modo di regolare i fiumi; libro che, se fosse stato pubblicato a suo <lb/>tempo, o avrebbe risparmiato in parte o avrebbe diminuiti i meriti <lb/>al Trattato del Michelini. </s>

<s>Incomincia a dire che fino allora, nei la&shy;<lb/>vori fatti sui fiumi, s'erano commessi di grandi errori, e s'era speso, <lb/>dal pubblico e dai privati, in false operazioni. </s>

<s>Nota poi come quegli <lb/>errori dipendessero principalmente da non essere conosciuti bene <lb/>i moti, a cui va soggetta l'acqua, e distingue quei moti in tre: <lb/><emph type="italics"/>spulsivo, naturale<emph.end type="italics"/> e <emph type="italics"/>laterale.<emph.end type="italics"/> Ammettendo nell'acqua il moto late&shy;<lb/>rale, o obliquo, come l'Autore stesso lo chiama, scansa il gravissimo <lb/>errore, in che incorse il Michelini, ma poi ci incappa al pari di lui, <lb/>quando distingue il moto <emph type="italics"/>spulsivo,<emph.end type="italics"/> ossia quello fatto nella pendenza <lb/>dell'alveo, dal naturale fatto nella perpendicolare, essendo che lo <lb/>spulsivo, non &egrave; un moto diverso, ma &egrave; una delle parti dello stesso <lb/>moto naturale, decomposto in due. </s></p><p type="main">

<s>Il moto spulsivo poi il Noferi lo riguarda come efficiente nel <lb/>venir premuta l'acqua dall'altr'acqua che lo precede, e cos&igrave; rende <lb/>la ragione dello scorrere i liquidi, anche in canali perfettamente <lb/>livellati. </s>

<s>Questa cos&igrave; importante dottrina era stata professata gi&agrave;, <lb/>contro la comune opinione degli idraulici, da Galileo, che il Noferi <lb/>ormeggia spesso con studio, che si direbbe servile. </s>

<s>Cos&igrave; occorren&shy;<lb/>dogli di trattar del problema della corda tesa, ricopia a parola ci&ograve; <lb/>che sta scritto nel IV Dialogo delle Due Nuove Scienze, e dettando <lb/>i suoi Discorsi in tempi, in cui certamente doveva essere stata fatta <lb/>e divulgata la celebre esperienza torricelliana, discorre della teoria <lb/>delle trombe idrauliche allo stesso modo, che se ne discorre nel I <lb/>dei citati Dialoghi, da Galileo. </s>

<s>Rimasto preso di grande ammira&shy;<lb/>zione alla lettura delle opere di lui, ne sceglie i pi&ugrave; curiosi e im&shy;<lb/>portanti problemi, e sotto il titolo di <emph type="italics"/>Ricreazioni matematiche<emph.end type="italics"/> gli <lb/>ordina in due libretti &ldquo; quali due libretti spero in breve farvi ve&shy;<lb/>dere. </s>

<s>Ma quell'opera poi che pi&ugrave; mi ha ritardato, &egrave; l'avere con&shy;<lb/>dotto a fine il mio Apollonio Pergeo, per benefizio ed utile degli <lb/>studiosi &rdquo; (MSS. Gal. </s>

<s>Disc. </s>

<s>T. XIV, c. </s>

<s>2). </s></p><p type="main">

<s>Quanto per&ograve; il Noferi &egrave; ossequioso verso Galileo, tanto par ir&shy;<lb/>riverente verso il Castelli. </s>

<s>La censura che egli fa della proposizione <lb/>fondamentale dimostrata nel Trattato delle Acque Correnti, che cio&egrave; <lb/>le velocit&agrave; sono in ragione inversa delle sezioni, non &egrave; per verit&agrave; di <lb/>matematico, n&egrave; si saprebbe altrimenti spiegare che in una smania <pb xlink:href="020/01/186.jpg" pagenum="167"/>del censore, d'introdur nella scienza quella sua novit&agrave; del <emph type="italics"/>moto <lb/>spulsivo.<emph.end type="italics"/></s></p><p type="main">

<s>Antonio Nardi, aretino, componeva col Magiotti e col Torricelli, <lb/>in Roma, quel triumvirato, che Galileo manda cos&igrave; spesso a salu&shy;<lb/>tare nelle sue lettere familiari. </s>

<s>Pi&ugrave; tardi, quando quel triumvirato <lb/>si sciolse, Michelangiolo Ricci, dando al Torricelli stesso venuto in <lb/>Firenze, le nuove degli amici lontani, in una sua lettera cos&igrave; gli <lb/>scriveva: &ldquo; Il signor Antonio Nardi fatica intorno l'Opera sua. </s>

<s>Ha <lb/>dato perfezione alla parte metafisica, ora &egrave; d'intorno la fisica, e <lb/>poi vedr&agrave; le matematiche, il che non potr&agrave; seguire prima di dieci <lb/>mesi ovvero in un anno. </s>

<s>E mi duole che tardi tanto ad uscire in <lb/>luce Opera, che si spera che debba essere doviziosa di tutte le <lb/>speculazioni, cio&egrave; pasto per ogni sorta di professori di scienza &rdquo; <lb/>(MSS. Gal. </s>

<s>Disc. </s>

<s>T. XLII, c. </s>

<s>121). Nel Giugno 1645 torna a scrivergli: <lb/>&ldquo; Il signor Antonio Nardi riverisce V. S. con ogni affetto, e nella <lb/>stampa del libro suo va un poco lento, perch&egrave; ci restano da rive&shy;<lb/>dere le materie matematiche, e non ha potuto attendere per molti <lb/>giorni, impedito da un poco d'indisposizione &rdquo; (ivi, c. </s>

<s>136). Non <lb/>sapremmo precisamente dire quanto quella indisposizione durasse, <lb/>ma sembra che l'Autore fosse impedito per qualche anno, dopo il <lb/>qual tempo scriveva il medesimo Ricci al Torricelli: &ldquo; Il sig. </s>

<s>Nardi <lb/>si trattiene in Arezzo e li giorni passati mi mand&ograve; l'Opera sua ori&shy;<lb/>ginale, perch&egrave; la facessi rivedere al S. </s>

<s>Uffizio &rdquo; (ivi, c. </s>

<s>183). </s></p><p type="main">

<s>Il libro e l'Opera originale del Nardi, di che qui si parla, porta <lb/>il titolo di <emph type="italics"/>Scene,<emph.end type="italics"/> senz'altro aggiunto nella fronte, ma, nell'Indice <lb/>finale, il titolo compiuto &egrave; di <emph type="italics"/>Scene Accademiche.<emph.end type="italics"/> &Egrave; un volumone <lb/>di pagine 1392, che riman tuttavia manoscritto, copiato da pi&ugrave; <lb/>mani, e non ha di autografo che alcune correzioni e postille, i <lb/>passi greci, e i disegni abbozzati delle figure geometriche. </s>

<s>Una certa <lb/>somiglianza di carattere calligrafico fece credere a qualcuno che <lb/>v'avesse dato mano, a copiar quelle carte, anche il Torricelli, ma <lb/>le sopra citate lettere del Ricci par che rendano poco probabile <lb/>quel supposto. </s></p><p type="main">

<s>Impedita per la morte dell'Autore la stampa, per la quale <lb/>tutto era preparato, il manoscritto, dagli eredi del Nardi pass&ograve; nel <lb/>concittadino di lui Francesco Redi, che par avesse intenzione di <lb/>mandarlo alla luce (Targioni, Aggrandim. </s>

<s>T. I. P. I. pag. </s>

<s>173). Ma <lb/>qualunque fosse il motivo, rimasto il volume tuttavia inedito, dal <lb/>Granduca Cosimo III che l'ebbe dal Redi, pass&ograve; alla biblioteca del <lb/>Museo fiorentino di Fisica e di Storia Naturale, d'onde finalmente <pb xlink:href="020/01/187.jpg" pagenum="168"/>and&ograve; a prender posto al numero XX, fra i tomi che compongono <lb/>la seconda Divisione dei manoscritti galileiani. </s></p><p type="main">

<s>Le scene in tutto son nove, e ciascuna &egrave; divisa in articoli, col <lb/>titolo di <emph type="italics"/>Vedute.<emph.end type="italics"/> Vi si tratta, senz'ordine, d'ogni soggetto scientifico, <lb/>cosicch&egrave; l'Opera somiglia a tanti numeri messi insieme di un gior&shy;<lb/>nale enciclopedico. </s>

<s>A que'tempi forse era questo il miglior modo <lb/>a diffondere la scienza, e tale dee essere stata senza dubbio l'in&shy;<lb/>tenzion dell'Autore. </s>

<s>Ora per&ograve;, un'opera scritta in quelle forme, non <lb/>sarebbe comportabile, per cui par che sia condannata in perpetuo <lb/>a rimanersene manoscritta. </s>

<s>Chi facesse, nonostante, una scelta degli <lb/>articoli di matematica o di fisica sperimentale, potrebbe arrecar <lb/>qualche giovamento alla storia della scienza, bench&egrave; il non aver <lb/>risentito il Nardi gli impulsi, che alle stesse scienze sperimentali <lb/>provennero dalla grande esperienza torricelliana, a que'medesimi <lb/>articoli, si diminuisca notabilmente l'importanza. </s></p><p type="main">

<s>La veduta 41 della Scena VII &egrave; intitolata: <emph type="italics"/>Censure sopra varii <lb/>pensieri di Galileo<emph.end type="italics"/> (pag. </s>

<s>967-74) pensieri tutti per&ograve; che concernono <lb/>le teorie galileiane del moto. </s>

<s>Ma qua e l&adot;, per le altre Scene, oc&shy;<lb/>corre pure all'Autore di intrattener l'esame critico sopra altre dot&shy;<lb/>trine del suo Maestro, le quali ora, con temperato zelo difende dalle <lb/>ingiuste censure altrui, e ora con filosofica libert&agrave; condanna ed <lb/>emenda. </s></p><p type="main">

<s>L'argutissima censura, che in quella Veduta, la quale porta il <lb/>titolo: <emph type="italics"/>Sopra la definizione dell'umido e sua Natura posta da Ar&shy;<lb/>chimede nei principii delle cose che galleggiano<emph.end type="italics"/> (pag. </s>

<s>873), fa il <lb/>Nardi del principio delle velocit&agrave; virtuali applicato da Galileo a di&shy;<lb/>mostrar l'equilibrio dei liquidi ne'vasi comunicanti, ci fa sovvenire <lb/>di un altro Discepolo, che, pure in materie idrauliche, oppose libere <lb/>censure alle dottrine dello stesso Galileo, e che, per aver affidata la <lb/>sua scienza a lettere, per la maggior parte inedite, &egrave; rimasto nella <lb/>Repubblica scientifica oscuro, o quanto pur si meriterebbe non ap&shy;<lb/>prezzato. </s>

<s>Costui &egrave; il fiorentino Senatore Andrea Arrighetti, di cui <lb/>cos&igrave;, in un poscritto di lettera a Galileo, scriveva il Castelli: &ldquo; Tengo <lb/>una lettera lunga del sig. </s>

<s>Andrea Arrighetti, sottilissima e bella, in <lb/>proposito di fiumi, nella quale ho avuto che imparare assai &rdquo; (Alb. </s>

<s><lb/>Supplem. </s>

<s>pag. </s>

<s>239). Questa, che forse &egrave; ancora inedita, dee essere <lb/>una di quelle fra le prime lettere, che Andrea scriveva a Niccol&ograve; <lb/>Arrighetti suo cugino intorno al fiume Bisenzio, professandovi dot&shy;<lb/>trine vere contro a quelle, riconosciute erronee, di Galileo. </s>

<s>E l'avere <lb/>il discepolo con sicurt&agrave; e dirittura colto nel segno meglio del suo <pb xlink:href="020/01/188.jpg" pagenum="169"/>Maestro, e il confessar che il Castelli fa dell'aver trovato da imparare <lb/>assai dalla scrittura di lui, compongono il pi&ugrave; bell'elogio, che si possa <lb/>fare di Andrea Arrighetti. </s>

<s>Nella grande raccolta fiorentina degli <lb/>Autori, che trattano del moto dell'acque, s'inserirono, nel IV Tomo, <lb/>sei lettere dell'Arrighetti al Castelli, nelle quali s'apre il fiore di <lb/>alcuni pensieri, che allegarono poi in squisitissimi frutti. </s>

<s>Tale &egrave;, <lb/>nella II Lettera, la legge della velocit&agrave; dei flussi, fior di pensiero <lb/>allegato nel Torricelli, e nel Newton fatto poi pi&ugrave; maturo; tale la <lb/>speculazione del librarsi i liquidi che scendono e risalgono per <lb/>lunghi canali, qual sarebbe quello che dalle fontane di Boboli faceva <lb/>zampillar le acque condottevi da Pratolino: sottile speculazione e <lb/>fecondo fiore di novit&agrave;, che se pure &egrave; allegato in frutto, non par <lb/>che la scienza ancora l'abbia colto maturo. </s></p><p type="main">

<s><emph type="center"/>VI.<emph.end type="center"/></s></p><p type="main">

<s>Chi si trattiene a meditare alquanto su questo primo e cos&igrave; <lb/>largo svolgimento delle nuove dottrine, in s&igrave; breve spazio di tempo, <lb/>che non oltrepassa, se non di pochissimi anni quello della morte di <lb/>Galileo, non pu&ograve; non rimanere ammirato di quella forza potente, <lb/>che valse a dare e a diffondere nella scienza tant'onda di vita. </s>

<s>Ma <lb/>pure, quella scienza ancora ha poco dello sperimentale. </s>

<s>La forma <lb/>dura tuttavia a signoreggiare sulla materia, la matematica prevale <lb/>alla fisica, e la speculazione, troppo sicura di s&egrave;, non degna di <lb/>scendere dalle sue alture per cimentarsi colla esperienza. </s>

<s>Che sia <lb/>veramente cos&igrave;, insigni esempii ci son porti in fin da coloro, che si <lb/>dissero precursori, ma che son da dir forse meglio attori di questa, <lb/>che per la nostra scienza si appella et&agrave; del Rinnovamento. </s>

<s>Tali <lb/>sarebbero, principali fra gli altri, il Maurolico e il Benedetti. </s>

<s>Il <lb/>primo di questi, nel trattar dell'iride, assegna all'angolo formato <lb/>dai raggi, che vengon da una gocciola della nube rorida all'occhio, <lb/>45 gradi, per l'iride interna, e 56 e un quarto per l'iride esterna. </s>

<s><lb/>Le dignit&agrave; matematiche son quelle, che lo conducono alla certezza <lb/>di cos&igrave; fatte conclusioni. </s>

<s>Ma pure, &egrave; vero che quegli angoli sono <lb/>alquanto minori, e il Maurolico lo sa, e a chi gli domanda come <lb/>la cosa vada <emph type="italics"/>nescio quid hic respondeam,<emph.end type="italics"/> ma la matematica non <lb/>pu&ograve; fallire, e potrebb'esser, soggiunge, che il non rispondere il fatto <pb xlink:href="020/01/189.jpg" pagenum="170"/>incerto ai calcoli certissimi, dipendesse dal non esser le gocciole <lb/>perfettamente sferiche, ma notabilmente allungate in ovale. </s></p><p type="main">

<s>In Galileo poi gli esempi, che si potrebbero citare, del prevaler <lb/>nelle sue dottrine le speculazioni alle esperienze, son tanti, che, <lb/>anche ai pi&ugrave; ritrosi a consentir con noi, parrebbero da vantaggio. </s>

<s><lb/>Egli par gi&agrave; che da s&egrave; stesso lo senta, e che si voglia far quasi <lb/>percotere il petto di rimbalzo dalla punta delle parole, che pone <lb/>in bocca a Simplicio: &ldquo; queste sottigliezze matematiche son vere <lb/>in astratto, ma applicate poi alla materia sensibile e fisica non ri&shy;<lb/>spondono &rdquo; (Alb. </s>

<s>I, 224). </s></p><p type="main">

<s>Sia primo a citare fra questi notabilissimi esempi il pendolo, <lb/>intorno al quale il giudizio di Galileo procede in modo simile a <lb/>quello del Maurolico, ora citato. </s>

<s>La matematica gli ha fatto con&shy;<lb/>cludere, per certissima dimostrazione, che le vibrazioni o ampie <lb/>per tutto il quadrante, o ristrette in piccolissimi archi sono in ogni <lb/>modo isocrone. </s>

<s>Nel fatto per&ograve; non son tali, e Galileo lo s&agrave;: sa che <lb/>le pi&ugrave; ampie sono alquanto pi&ugrave; diuturne. </s>

<s>A chi gli domanda come <lb/>quel fatto vada, <emph type="italics"/>Nescio quid hic respondeam,<emph.end type="italics"/> ma potrebb'esser, <lb/>soggiunge, che ci&ograve; dipenda dall'esser le vibrazioni, che vanno pi&ugrave; <lb/>al largo, alquanto di pi&ugrave; indugiate dalla resistenza maggior che <lb/>incontran nell'aria. </s>

<s>Eppure si sarebbe potuto anche da ci&ograve; facil&shy;<lb/>mente deliberare, con una tale esperienza, che pu&ograve; sovvenire alla <lb/>mente di tutti, bench&egrave; l'Huyghens sia stato quello che primo l'ha <lb/>suggerita. </s>

<s>Consiste quella facilissima e concludentissima esperienza <lb/>in prender due pendoli di lunghezza uguale, e in dar le mosse a <lb/>ciascuno dalla medesima parte, in modo per&ograve; che l'uno scenda <lb/>molto da alto e l'altro da basso. </s>

<s>&Egrave; facile veder che presto i due <lb/>pendoli non passano pi&ugrave; il perpendicolo insieme, ma quel che va <lb/>pi&ugrave; ristretto &egrave; giusto quello che precede. </s></p><p type="main">

<s>E la celebre dimostrazione della legge della caduta dei gravi, <lb/>egli &egrave; pure un fatto che Galileo non la raccolse altrimenti, che per <lb/>una matematica conclusione dal principio che le velocit&agrave; sono pro&shy;<lb/>porzionali ai tempi. </s>

<s>Il riscontro dell'esperienza, cos&igrave; minutamente <lb/>descritta nel III Dialogo delle Due Nuove Scienze (Alb. </s>

<s>XIII, 172, 73), <lb/>&egrave; affatto superfluo, perch&egrave; nessun crede all'Autore che, dal pesar <lb/>dell'acqua sgocciolante dalla clessidra, potesse aver la misura giusta <lb/>di que'minimi tempi, difficilissimi a trovar con gli stessi pi&ugrave; squisiti <lb/>cronometri moderni. </s></p><p type="main">

<s>Altro insigne esempio del prevaler nella mente di Galileo la <lb/>precisione matematica e l'ordine geometrico alla osservazione dei <pb xlink:href="020/01/190.jpg" pagenum="171"/>fatti, &egrave; quello che concerne le orbite dei pianeti. </s>

<s>Il Keplero aveva <lb/>dimostrato, come cosa di fatto, che quelle orbite sono ellittiche. </s>

<s>Ma <lb/>ci&ograve;, secondo Galileo, repugna alla platonica perfezione degli ordi&shy;<lb/>namenti celesti, per cui tenacemente si attiene alla geometria dei <lb/>circoli, e rifugge dalla fisica delle ellissi. </s>

<s>Quando poi pi&ugrave; tardi ri&shy;<lb/>trov&ograve; la legge dei moti ne'pendoli di varie lunghezze, ritrov&ograve; anco <lb/>insieme un nuovo argomento per non dover consentire a un'altra <lb/>delle leggi planetarie, scoperte pur dal Keplero. </s>

<s>Rassomigliando nei <lb/><emph type="italics"/>Massimi Sistemi<emph.end type="italics"/> i pianeti a tanti pendoli, che abbiano il loro centro <lb/>di sospensione nel sole, la sua matematica gli concludeva che i <lb/>tempi periodici debbono essere proporzionali alle radici degli assi. </s>

<s><lb/>Or questa sua matematica volle Galileo che prevalesse al fatto con&shy;<lb/>cluso dal Keplero, secondo il quale, i quadrati dei tempi periodici <lb/>sarebbero come i cubi delle medie lunghezze degli assi. </s>

<s>Cos&igrave; venne <lb/>a persuadersi di pi&ugrave;, che le tre leggi Kepleriane, in cui parevagli <lb/>di non ravvisar la solita Natura geometrizzante, non fossero pi&ugrave; che <lb/>altrettante chimere. </s></p><p type="main">

<s>Ma che molte dottrine di Galileo sien vere in astratto e poi <lb/>non corrispondano ai fatti, come diceva Simplicio, abbiamo, a per&shy;<lb/>suadere i pi&ugrave; ritrosi, un argomento concludentissimo, in quei teo&shy;<lb/>remi del moto applicato all'acque correnti nella celebre Lettera sul <lb/>fiume Bisenzio. </s>

<s>Ivi si professa dall'Autore il principio che l'acqua, <lb/>fra tutti i corpi gravi, &egrave; quella, in cui si verificano pi&ugrave; esattamente <lb/>le leggi della caduta dei gravi, specialmente lungo i piani inclinati, <lb/>e ci&ograve; perch'ella non &egrave; soggetta, per sua propria natura, agli urti <lb/>e agli attriti, che sogliono essere le pi&ugrave; valide cause, per cui si <lb/>alterano quelle stesse leggi. </s>

<s>Cos&igrave;, immaginandosi un piano liquido <lb/>tangente ne'punti di sporgenza delle asperit&agrave; delle rive o dell'alveo, <lb/>l'acqua, che riceve impedimento da s&igrave; fatte asperit&agrave;, non &egrave; che <lb/>quella sola, la quale si trova rinchiusa fra quel piano immaginario <lb/>e le sinuosit&agrave; e le sporgenze delle rive e dell'alveo. </s>

<s>Il rimanente <lb/>scorre, per mezzo a quello stesso piano liquido, senza violenza di <lb/>attrito, come un corpo duro sopra un tersissimo specchio. </s>

<s>Da ci&ograve; <lb/>derivava per legittima conseguenza che la corrente dovesse giungere <lb/>al suo termine con tutta la velocit&agrave;, che conviene alla caduta. </s>

<s>Or <lb/>non par credibile che Galileo approvasse tali teorie, tanto eviden&shy;<lb/>temente contrarie all'esperienza. </s>

<s>&Egrave; chiaro infatti, secondo quelle <lb/>teorie, che, dovendo essere le fila superficiali della corrente tutte <lb/>ugualmente veloci, non vi si dovrebbe mai vedere nel mezzo il <lb/>filone. </s>

<s>Che se davvero ogni fiume, specialmente in tempo di piena, <pb xlink:href="020/01/191.jpg" pagenum="172"/>giunge allo sbocco con tutta la velocit&agrave; conveniente alla caduta, <lb/>chi non vede che, arrivate a un punto, le sezioni non si potrebbero <lb/>ritenere pi&ugrave; insieme, come giusto si osserva nel cader delle trosce <lb/>d'acqua da qualche grande altezza? </s>

<s>Fu per questo che il Barattieri, <lb/>con giudizio diverso da quello di Galileo, stimando i fatti pi&ugrave; con&shy;<lb/>cludenti delle matematiche dimostrazioni, si rivolse a professar, per <lb/>l'acqua e per tutti i gravi cadenti in generale, la legge dimostrata <lb/>dal Tartaglia delle velocit&agrave; proporzionali ai semplici spazi, a pre&shy;<lb/>ferenza della vera, dimostrata gi&agrave; dallo stesso Galileo. </s>

<s>Anzi, paren&shy;<lb/>dogli dover esser la corrente, anco velocitata cos&igrave;, troppo pi&ugrave; pre&shy;<lb/>cipitosa di quel che non dimostrano i fatti, considera che ella vien <lb/>giustamente rattemperata, nel suo corso, da tanti impedimenti. </s></p><p type="main">

<s>Qual pi&ugrave; valido argomento di questo si potrebb'egli recare a <lb/>prova del nostro assunto, che cio&egrave; Galileo faceva prevalere le astratte <lb/>speculazioni ai fatti? </s>

<s>E i fatti, dall'altra parte, oltre ad essere per <lb/>s&egrave; medesimi cos&igrave; manifesti, gli eran messi in considerazione da <lb/>quelle lunghe e dotte lettere che, a dimostrar la fallacia di que'suoi <lb/>idraulici insegnamenti, con tanta filosofica libert&agrave;, gli scriveva Andrea <lb/>Arrighetti. </s></p><p type="main">

<s>Questo Arrighetti, coll'Aggiunti, col Castelli e con pochi altri, <lb/>son senza dubbio de'primi che, progredendo negli studi sperimen&shy;<lb/>tali, passano dalle astratte forme geometriche a considerare le par&shy;<lb/>ticolari affezioni della materia. </s>

<s>Ma gli esempi ancora, come si disse, <lb/>son pochi: le vie sono incerte, e da tutto apparisce che l'arte di <lb/>sperimentare &egrave; tuttavia ne'suo&igrave; principii. </s>

<s>Per vederla nel suo pieno <lb/>esercizio conviene ancora aspettare che la celebre Accademia del <lb/>Cimento sia convocata, e che ella abbia almeno pubblicati i suoi <lb/><emph type="italics"/>Saggi.<emph.end type="italics"/> Ma, in questo non breve spazio di tempo, la Francia &egrave; com&shy;<lb/>mossa di maraviglia alle esperienze del Pascal, dell'Auzout, del <lb/>Roberval, del Pacquet; l'Inghilterra a quelle del Boyle; la Ger&shy;<lb/>mania a quelle del Guericke, e, a restare ammirata alle nuove <lb/>esperienze di Valeriano Magno, non ultima di tutte &egrave; la solitaria <lb/>Polonia. </s>

<s>Il vantarsi perci&ograve; che la nostra Accademia del Cimento <lb/>sia stata la prima, fra tutte le altre instituite in Europa, si riduce <lb/>a una vanit&agrave;, considerando che i nomi ora citati valgono, ciascuno <lb/>per s&egrave;, quanto un'intiera Accademia, e che i <emph type="italics"/>Saggi di Naturali <lb/>Esperienze<emph.end type="italics"/> paragonati agli <emph type="italics"/>Esperimenti fisico meccanici,<emph.end type="italics"/> appariscon <lb/>non pi&ugrave; che come una spigolatura dopo la messe. </s></p><p type="main">

<s>In ogni modo per&ograve; &egrave; verissimo, a nostro conforto, che quelle <lb/>onde di scienza sperimentale che si diffondono cos&igrave; al largo per <pb xlink:href="020/01/192.jpg" pagenum="173"/>tutta l'Europa, ebbero il loro centro d'impulsione in Italia. </s>

<s>Che fa, <lb/>in vero, il Pascal a Roano, in mezzo a quella folla di popolo, per <lb/>gran curiosit&agrave; concorsavi d'ogni parte? </s>

<s>Verifica un'esperienza ve&shy;<lb/>nuta d'Italia, la conferma con altre nuove stupende esperienze, e <lb/>si studia in ogni modo di persuadere i contradicenti. </s>

<s>Che fanno <lb/>l'Auzout, e il Roberval a Parigi, se non che diffonder la notizia di <lb/>quella esperienza italiana nelle pubbliche scuole, alla presenza dei <lb/>giovani studiosi; e che fa il Pacquet, se non che applicare quella <lb/>stessa esperienza a risolvere compiutamente il problema arveiano <lb/>della circolazione del sangue? </s>

<s>E che altro mai fa il Guericke, in <lb/>mezzo ai principi, ai magnati e al popolo concorsi sulle pubbliche <lb/>piazze di Magdeburgo, se non che sottoporre a nuove e maravi&shy;<lb/>gliose esperienze i concetti stessi di Galileo? </s>

<s>Valeriano Magno fa <lb/>stupire la corte del Re di Polonia con una esperienza, che tutti <lb/>dicono esser venuta di Firenze, ma che egli spaccia per invenzione <lb/>sua propria. </s>

<s>Nessuno per&ograve; di questi stranieri s'esercit&ograve; mai con <lb/>tant'arte e con tanto studio intorno a quella italiana esperienza, <lb/>quanto Roberte Boyle, emulo al connazionale suo Guglielmo Gilbert, <lb/>in dare al pubblico i primi e pi&ugrave; splendidi esempi dell'arte spe&shy;<lb/>rimentale. </s></p><p type="main">

<s>S'indovina assai facilmente che l'esperienza italiana, di cui si <lb/>parla, &egrave; quella celeberrima dell'argento vivo, fatta dal Torricelli, <lb/>e da cui veramente l'arte sperimentale ha principio. </s>

<s>Scriveva il <lb/>Pecquet, negli Esperimenti nuovi anatomici, e dava gran lode al <lb/>Pascal &ldquo; qui primus in Gallia nostra vix natum apud exteros, et in <lb/>cunabulis pene suffocatum de vacuo experimentum hydrargirio non <lb/>solum, sed et liquoribus suscitavit, imo tam felici provexit mirabilis <lb/>industriae successu, ut per totam Europam tentandi vacui studium <lb/>verae sapientiae cultoribus indiderit &rdquo; (Parisiis, 1654, pag. </s>

<s>55). Ora <lb/>si domanda: aveva egli ragione il Pecquet d'affermare che l'espe&shy;<lb/>rienza torricelliana fosse rimasta soffocata nella cuna? </s>

<s>Si comprende <lb/>che la ragione del vantato nostro primato, sopra le altre nazioni <lb/>europee, dipende da questa risposta. </s>

<s>E noi, dandola con la solita <lb/>nostra imparzialit&agrave;, diciamo che, a giudicar dai pubblici documenti, <lb/>il Pecquet aveva ragione. </s>

<s>Nel 1648 infatti si pubblicarono le prime <lb/>esperienze del Pascal fatte a Roano; nel 1654, il Pecquet stesso <lb/>pubblicava i suoi Nuovi Esperimenti anatomici; nel 1657 lo Schott <lb/>dava notizia al pubblico, a nome del Guericke, dei primi Esperi&shy;<lb/>menti Nuovi di Magdeburgo, e il Boyle, nel 1659, pubblicava i suoi <lb/>Esperimenti fisico meccanici. </s>

<s>In Italia, dall'epistola di Timeo Lo-<pb xlink:href="020/01/193.jpg" pagenum="174"/>crese in fuori, che &egrave; del 1648, nessuna esercitazione sull'esperienza <lb/>torricelliana comparve in pubblico prima del 1666, anno in cui si <lb/>misero in luce i <emph type="italics"/>Saggi<emph.end type="italics"/> della fiorentina Accademia. </s>

<s>Se poi si va a <lb/>ricercare quel che rimase rinchiuso fra le splendide pareti del pa&shy;<lb/>lazzo Pitti, o venne affidato a carte mutilate e neglette, il Pecquet <lb/>non afferm&ograve; cosa che fosse mai tanto lontana dal vero. </s></p><p type="main">

<s>Non si pu&ograve;, in questo proposito, non meditar profondamente <lb/>sopra certi fatti particolari, che altri forse direbbe dipendere da un <lb/>Destino, ma che meglio si attribuirebbero a un indole propria della <lb/>gente italiana. </s>

<s>A legger la Narrazione, che il Roberval fa nella sua <lb/>Lettera al Noyers, o quel che scrive il Magno nella <emph type="italics"/>Dimostrazione <lb/>oculare,<emph.end type="italics"/> e lo Schott e il Guericke negli Esperimenti di Magdeburgo, <lb/>si resta maravigliati a sentir che francesi, alemanni, polacchi, no&shy;<lb/>bili e plebe, principi e magnati concorressero a veder lo spettacolo <lb/>dell'esperienza del vuoto in tanta folla, da non esserne capaci le <lb/>pubbliche piazze; mentre in Roma, Gaspero Berti, alquanti anni <lb/>prima che ne sapessero nulla que'francesi, quegli alemanni, quei <lb/>pollacchi, al suo pubblico spettacolo non aveva assistenti che il Ma&shy;<lb/>giotti, il Kircher, lo Zucchi, e pochi altri dotti. </s>

<s>Anche in Firenze <lb/>il Granduca, per compiacer talvolta qualche straniero erudito, chia&shy;<lb/>mava il Torricelli a ripetere l'esperienza sotto le solitarie amene <lb/>ombre del giardino di Boboli; compiacenza offerta raramente per&ograve;, <lb/>e toccata a pochi altri, oltre al Moncony e al Mersenno, che primo <lb/>ne di&egrave; avviso al Pascal, da cui, come scintilla, divamp&ograve; l'incendio <lb/>per tutta l'Europa. </s></p><p type="main">

<s>Che si dir&agrave;, a spiegar questi fatti, dell'indole degli italiani? </s>

<s><lb/>Si dir&agrave; che non avevano amore alla scienza? </s>

<s>Ma il non trarre il <lb/>popolo nostro, come gli stranieri, a spettacolo s&igrave; fatto, forse niente <lb/>altro dice, se non ch'egli era pi&ugrave; colto, essendo sempre la curio&shy;<lb/>sit&agrave; figliola dell'ignoranza. </s>

<s>Una tal curiosit&agrave; &egrave; poi naturale che non <lb/>frugasse troppo a vivo una gente avvezza oramai a sentir delle tante <lb/>maraviglie operate da Galileo. </s></p><p type="main">

<s>Si dir&agrave; che non presentivano i Nostri le conseguenze di quei <lb/>fatti spettacolosi, dai quali sarebbe incominciato, e avrebbe ricevuto <lb/>la fisica sperimentale cos&igrave; valido impulso? </s>

<s>Che non avessero cos&igrave; <lb/>vivo quel presentimento forse &egrave; vero, perch&egrave; non si saprebbe spie&shy;<lb/>gare altrimenti il silenzio, che si tenne da tutti intorno alla storia <lb/>della grande scoperta. </s>

<s>Non &egrave; cosa che tanto rechi meraviglia, quanto <lb/>il veder il Viviani, che v'ebbe tanta parte, e molti altri che, anche <lb/>morto il Torricelli, potevano attinger notizia da lui; come ci lascino <pb xlink:href="020/01/194.jpg" pagenum="175"/>cos&igrave; al buio intorno a ci&ograve; che dette occasione alla esperienza del&shy;<lb/>l'argento vivo, contentandosi di accennare ai concetti di Galileo, <lb/>che saranno stati un occasione s&igrave;, ma un occasione troppo remota. </s>

<s><lb/>Il Mersenno, e tutti noi si vorrebbe saper qual fu l'immediata <lb/>scintilla, da cui si accese la gran fiamma, e nessun lo sa dire, n&egrave; <lb/>si legge in nessuna di quelle tante carte dei manoscritti galileiani, <lb/>d'onde pur s'attinge la segreta storia di tante cose. </s>

<s>Altra gran ma&shy;<lb/>raviglia &egrave; che il Torricelli non pubblicasse e nemmeno scrivesse <lb/>di proposito nulla intorno alla sua grande invenzione. </s>

<s>Le lettere <lb/>stesse a Michelangiolo Ricci, che sarebbero forse andate smarrite <lb/>se il Borelli, recatele da Roma, non l'avesse consegnate al principe <lb/>Leopoldo de'Medici, non si pubblicarono prima del 1663, nella Let&shy;<lb/>tera di Timauro ai Filaleti. </s>

<s>Il Torricelli e il Viviani &egrave; verosimile <lb/>che non avrebbero operato cos&igrave;, se avessero presentito i benefizi <lb/>immensi, che sarebbero derivati alla scienza universale da quel loro <lb/>cannello di vetro, mezzo pieno di mercurio e mezzo vuoto. </s></p><p type="main">

<s>Il non aver per&ograve; questo presentimento e il non aver dato a <lb/>quel loro sperimentale apparato tutta quella importanza, che gli <lb/>dettero gli stranieri, non vuol dir, com'affermava il Pecquet, che <lb/>l'avessero lasciato morire appena nato. </s>

<s>A rivendicar l'onta, che si <lb/>fa all'Italia con quelle parole dall'anatomico francese, sovverranno <lb/>i fatti, pochi ma concludenti, da cui si prova come, dopo le prime <lb/>esperienze, proseguisse, nello studio delle propriet&agrave; del vacuo e <lb/>degli effetti naturali della pressione ammosferica, il Torricelli aiu&shy;<lb/>tato e sollecitato all'opera dall'amico suo Raffaello Magiotti. </s></p><p type="main">

<s>La lettera del di 11 di Giugno 1644, dove l'Autore descrive a <lb/>Michelangiolo Ricci l'esperienza dell'argomento vivo, perch&egrave; la pri&shy;<lb/>ma fra le rimaste, si d&agrave; come primo documento degli studi speri&shy;<lb/>mentali su quel soggetto. </s>

<s>Ma chi attende bene, rileva con facilit&agrave;, <lb/>dalle sue proprie parole, che lo scrivente era gi&agrave; fatto certo, non <lb/>solo che l'aria pesa, ma che il peso di lei varia da un giorno al&shy;<lb/>l'altro, per cui l'assunto di quella Lettera al Ricci non &egrave; che di <lb/>dargli notizia de'tentativi fatti per costruire un nuovo strumento, <lb/>da servir di misura a quelle ammosferiche variazioni. </s>

<s>Or perch&egrave; la <lb/>notizia di una cosa tanto nuova, qual'&egrave; quella dell'aria, che preme <lb/>con varia forza di torchio da un giorno all'altro, non poteva esser <lb/>se non che frutto di ripetute diligentissime esperienze, si veda <lb/>quanto mal s'appongono coloro, che riguardano l'esperienza del <lb/>mercurio nel cannello di vetro, alle mani del Torricelli, come un <lb/>fatto solitario e indipendente, senza principio e senza sequele. </s>

<s>Delle <pb xlink:href="020/01/195.jpg" pagenum="176"/>notizie delle esperienze precedenti a quella del mercurio sodisfa&shy;<lb/>remo ai lettori in luogo pi&ugrave; opportuno: quanto alle conseguenti, <lb/>basti il citar la testimonianza dei nostri Accademici del Cimento, <lb/>i quali riconoscono il Torricelli per primo Autore, che sperimen&shy;<lb/>tasse la vita degli animali nel vuoto. </s>

<s>E quando pur ci mancassero <lb/>altre testimonianze, chi potrebbe creder che colui, il quale apr&igrave; la <lb/>via a cos&igrave; nuove e importanti esperienze, si rimanesse dal vagar <lb/>per altre parti della spaziosa ubert&agrave; di quel campo? </s>

<s>Vero egli &egrave; <lb/>bene che mancava uno strumento adattato, perch&egrave;, diffidando forse <lb/>delle legature, non pens&ograve; n&egrave; ard&igrave; di aprire i fondi dei vasi, per <lb/>introdurvi dentro gli oggetti. </s>

<s>Ma chi oserebbe prescrivere cos&igrave; fatti <lb/>limiti a quel grandissimo ingegno? </s>

<s>Chi potrebbe decider se sia <lb/>vero che non avesse tempo di mettersi attorno a raffinare quelle <lb/>esperienze nel vuoto, o non sia avvenuto piuttosto che ne sia per&shy;<lb/>duta la memoria, come di tante altre cose di lui e del Magiotti? </s></p><p type="main">

<s>Raffaello Magiotti, nato in Toscana nel paesello di Montevarchi, <lb/>&egrave; un elettissimo ingegno, ma sventuratamente rimasto soffocato dalla <lb/>polvere della Biblioteca Vaticana. </s>

<s>Quella corrispondenza di amiche&shy;<lb/>voli ufficii e di studii, che pass&ograve; fra lui e il Torricelli, quando gio&shy;<lb/>vani in Roma s'educavano l'ingegno alle nuove dottrine galileiane <lb/>sotto la disciplina del P. Castelli; si mantenne integra e viva anco <lb/>dappoi, che il Torricelli stesso era venuto a Firenze, e vi s'era <lb/>stabilito in qualit&agrave; di Matematico del Granduca. </s>

<s>Le lettere fra i due <lb/>amici intercedevano assai frequenti, e non occorreva speculazione <lb/>o scoperta all'ingegno e all'esercizio dell'uno, che non fosse co&shy;<lb/>municata o conferita con l'altro. </s>

<s>Pensa il Torricelli che le velocit&agrave; <lb/>del flusso dei liquidi non siano proporzionali alle semplici altezze <lb/>ma alle loro radici, e il Magiotti conferma il fatto con ripetute e <lb/>diligenti esperienze. </s>

<s>Si &egrave; il Torricelli stesso abbattuto a nuovi fatti <lb/>curiosi circa il galleggiare e il sommergersi alcune palline di vetro <lb/>vuote e aperte in un sottilissimo foro, per dove pu&ograve; passare o acqua <lb/>o nuov'aria, e avvisa di questa curiosit&agrave; proponendogliela sotto forma <lb/>di Problemi il Magiotti, che gli risolve mirabilmente nell'unica <lb/>scrittura, che di lui s'abbia alle stampe, sotto il titolo di <emph type="italics"/>Renitenza <lb/>certissima dell'acqua alla compressione.<emph.end type="italics"/></s></p><p type="main">

<s>Che le prime scoperte del variar della pressione ammosferica <lb/>fossero comunicate dall'Autore al suo amico in Roma, pi&ugrave; che pro&shy;<lb/>babile, sembra a noi cosa certa, e se ci fossero rimaste le lettere, <lb/>nelle quali il Torricelli conferiva col Magiotti quelle sue stesse sco&shy;<lb/>perte, non sarebbe lasciato forse altro pi&ugrave; da desiderare alla cu-<pb xlink:href="020/01/196.jpg" pagenum="177"/>riosit&agrave; della storia. </s>

<s>In ogni modo, anco dai pochi documenti che <lb/>ci son pervenuti, o da qualche accenno, che si trova fatto qua e l&agrave; <lb/>dagli scrittori, s'argomenta che il Magiotti s'esercit&ograve; intorno all'espe&shy;<lb/>rienza del vuoto in pi&ugrave; varii modi, e con pi&ugrave; solerzia, di quel che <lb/>non facessero qualche anno dopo tanti stranieri. </s>

<s>Lo Schott l'anno&shy;<lb/>vera fra coloro che assisterono al pubblico esperimento del vuoto, <lb/>fatto con l'acqua dentro un lungo tubo applicato alla parete esterna <lb/>della propria casa d'abitazione da Gaspero Berti. </s>

<s>Il Mersenno per&ograve;, <lb/>non come semplice spettatore ce lo rappresenta, ma come princi&shy;<lb/>pale attore della nuova e importante esperienza. </s>

<s>Nel capitolo VI <lb/>delle sue <emph type="italics"/>Nuove Osservazioni,<emph.end type="italics"/> dopo avere accennato alla possibilit&agrave; <lb/>del vacuo, e all'esperienze pi&ugrave; opportune per dimostrarlo, soggiunge: <lb/>&ldquo; Bombus volantis crabronis aptissimus videtur, sed et aquae, vel <lb/>alterius liquoris guttulas possis in illo tubo vacuo experiri, num <lb/>tubo concusso guttulae illae, lapidum instar parietes internos cy&shy;<lb/>lindri percussurae sint ut clariss. </s>

<s>Magiottus in tubo factum esse <lb/>dicebat, ex quo fuerat haustus aer diabete &rdquo; (T. III. Parisiis, 1647, <lb/>pag. </s>

<s>104, 5). Da s&igrave; importante documento si raccoglie dunque, che <lb/>infin dal 1644, o in quel torno che il Mersenno trovavasi a Roma, <lb/>il Magiotti usava di fare il vuoto colla siringa, e per tal modo spe&shy;<lb/>riment&ograve; il colpo secco, che danno i liquidi, non impediti ne fra&shy;<lb/>stagliati dall'aria. </s>

<s>Questo solo fatto attesta che il nostro sperimen&shy;<lb/>tatore era proceduto cos&igrave; avanti, da raggiungere quasi il Boyle, e <lb/>da emulare gli stessi Accademici fiorentini, che sarebbero venuti <lb/>parecchi anni dipoi. </s></p><p type="main">

<s>Anzi di questa ultima nostra asserzione abbiam certezza di <lb/>prove da alcune lettere del Borelli. </s>

<s>Essendo egli nell'estate del 1658 <lb/>in Roma, ebbe ordine dal principe Leopoldo d'informarsi di ci&ograve; <lb/>che fosse avvenuto dei manoscritti lasciati dopo la morte dal Ma&shy;<lb/>giotti. </s>

<s>E raccolse dalle sue informazioni, il Borelli, come il cardinal <lb/>Sacchetti, alle mani del quale erano venuti que'fogli, avessegli con&shy;<lb/>segnati a Michelangiolo Ricci, perch&egrave; gli ordinasse in quel modo <lb/>che sapesse migliore. </s>

<s>&ldquo; Mi dice per&ograve; il detto Signore (cio&egrave; il Ricci, <lb/>e son parole dello stesso Borelli) che pochissime cose buone ha <lb/>ritrovato fra i detti scartafacci, particolarmente di quelle belle cose <lb/>geometriche e filosofiche che aveva ritrovato quel grande ingegno, <lb/>e queste per esser notate in cartucce furono disprezzate e poi bru&shy;<lb/>ciate da quella canaglia che aveva cura di spurgare le case dopo <lb/>la peste &rdquo; (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XVI. c. </s>

<s>100). </s></p><p type="main">

<s>Non sodisfatto, il Principe insiste per aver pi&ugrave; particolari in-<pb xlink:href="020/01/197.jpg" pagenum="178"/>formazioni, e dopo pochi giorni, il d&igrave; 3 d'Agosto, il Borelli risponde: <lb/>&ldquo; Mi sono poi meglio informato di quelle poche scritture rimaste <lb/>del signor Magiotti.... Di pi&ugrave; vi sono alcune poche sperienze sopra <lb/>il vaso d'argento vivo.... e per quanto mi dice il signor Michelan&shy;<lb/>giolo non vi &egrave; niente di pi&ugrave; di quello, che si &egrave; sperimentato nel&shy;<lb/>l'Accademia di Vostra Altezza &rdquo; (ivi, c.103). Ora, se si ripensi che <lb/>tra le prime e principali cure dell'Accademia del Cimento fu quella <lb/>di sperimentare nel vaso dell'argento vivo, e che moltissime e delle <lb/>principali fra queste stesse esperienze ne erano state fatte gi&agrave; nel&shy;<lb/>l'estate del 58, quando appunto scriveva il Borelli; si concluder&agrave; <lb/>dunque dalle parole di lui che il Magiotti, se non aveva fatto di <lb/>pi&ugrave;, aveva fatto almeno, intorno all'esperienza torricelliana, tutto <lb/>quel che nel Libro dei Saggi di Naturali Esperienze, dopo pi&ugrave; che <lb/>22 anni, vi fu particolarmente narrato e descritto. </s>

<s>Che se veramente <lb/>&egrave; cos&igrave;, vedasi quanto a torto asserisse il Pecquet essere l'esperi&shy;<lb/>mento dell'idrargiro <emph type="italics"/>vix natum<emph.end type="italics"/> appresso noi italiani, <emph type="italics"/>et in cuna&shy;<lb/>bulis suffocatum.<emph.end type="italics"/></s></p><p type="main">

<s>Ma insomma, la ragione e i diritti del primato d'Italia ne'pro&shy;<lb/>gressi delle scienze sperimentali resultano da documenti sconosciuti <lb/>non solo al Pecquet, e agli altri stranieri, ma non saputi nemmeno <lb/>da molti di noi italiani, che pure abbiamo cos&igrave; gran pretensioni, e <lb/>meniamo cos&igrave; gran vanto. </s>

<s>I nostri competitori perci&ograve; hanno avuto <lb/>fin qui ragione o di andare in collera con noi, o di deriderci, com&shy;<lb/>patendo alla nostra vanit&agrave;, e avranno ragione ancora di farlo, in&shy;<lb/>fintanto che non si confermi quel nostro primato sopra pi&ugrave; stabile <lb/>fondamento. </s>

<s>Alla patria nostra non mancher&agrave;, speriamo, chi voglia <lb/>e sappia degnamente farlo, ma intanto ne tratteremo qualche cosa <lb/>noi, quanto lo comporti la sufficienza nostra e la brevit&agrave; richiesta <lb/>al presente Discorso. </s></p><p type="main">

<s><emph type="center"/>VII.<emph.end type="center"/></s></p><p type="main">

<s>Perch&egrave; noi teniamo per cosa certa aver l'arte sperimentale <lb/>avuto i suoi primi principii e i suoi primi istituti dal Torricelli, e <lb/>perch&egrave; i cenni gi&agrave; fatti, essendo troppo scarsi all'importanza del <lb/>soggetto, richiedono d'esser suppliti e confortati d'altri argomenti; <lb/>giova, prima, intrattenere alquanto la nostra considerazione sulla <pb xlink:href="020/01/198.jpg" pagenum="179"/>persona di lui, che, dopo Galileo, &egrave; al parer nostro il principale <lb/>attore di questa Parte della nostra Storia. </s></p><p type="main">

<s>Evangelista Torricelli, a cui si d&agrave; da molti per patria Faenza, <lb/>si sent&igrave; consapevole della potenza del proprio ingegno alla lettura <lb/>dei Dialoghi delle Due Nuove Scienze, ai teoremi dimostrati ne'quali <lb/>fece alcune aggiunte o <emph type="italics"/>progressi,<emph.end type="italics"/> com'ei stesso si esprime (MSS. <lb/>Gal. </s>

<s>Disc. </s>

<s>T. XL, c. </s>

<s>78), che ordinati e trascritti, verso il Febbraio <lb/><figure id="id.020.01.198.1.jpg" xlink:href="020/01/198/1.jpg"/><lb/>del 1641, mand&ograve; al suo Maestro e Protettore Benedetto Castelli. </s>

<s>Il <lb/>Castelli fece di ci&ograve; consapevole Galileo, che se ne rallegr&ograve; molto, <lb/>e nel seguente aprile invitava l'Autore di quei <emph type="italics"/>progressi<emph.end type="italics"/> a tratte&shy;<lb/>nersi per qualche giorno seco in Arcetri. </s>

<s>Il principe Leopoldo poi <lb/>fece s&igrave;, che la semplice visita si riducesse a stabile soggiorno. </s>

<s>Tal <lb/>notizia raccogliesi dalla minuta autografa di una lettera, che lo <lb/>stesso principe indirizzava a Michelangiolo Ricci, nella quale, a <pb xlink:href="020/01/199.jpg" pagenum="180"/>proposito del nuovo libro che meditava il Borelli sulla forza della <lb/>percossa, scrive che la buona memoria di Galileo gli aveva detto <lb/>pi&ugrave; volte d'aver ritrovata la misura di quella forza &ldquo; ma non pot&egrave; <lb/>per l'et&agrave; o per qualsivoglia altro accidente, che ne fosse cagione, <lb/>darla fuori, com'io le feci ben cento volte istanza, ed al qual fine <lb/>condussi qui il Torricelli di suo consenso, perch&egrave; potesse servire <lb/>in mettere in carta i suoi pensieri, ma tutto fu invano &rdquo; (MSS. Gal. </s>

<s><lb/>Cim. </s>

<s>T. XXIII. c. </s>

<s>113). Galileo che, secondo narreremo a suo luogo, <lb/>aveva gi&agrave; nell'animo repudiata quella speculazione della percossa, <lb/>si proponeva di conferire col Torricelli altri suoi pensieri matema&shy;<lb/>tici e fisici, per poter con l'aiuto di lui ripulirli e mandarli alla <lb/>luce (Alb. </s>

<s>VII. pag. </s>

<s>367). In effetto per&ograve; non fece aiutarsi che nelle <lb/>aggiunte, nelle correzioni dei Dialoghi del Moto, e nel nuovo ordine <lb/>che meditava di dare ai teoremi dimostrati nel Dialogo terzo. </s>

<s>N&egrave;, <lb/>a quel che apparisce dai manoscritti galileiani, furono scarsi intorno <lb/>a ci&ograve; gli aiuti prestati dal Torricelli, tanto pi&ugrave; se si ripensi ch'ei <lb/>non istette ospite in Arcetri che dall'Ottobre al Gennaio. </s></p><p type="main">

<s>Morto Galileo, il Torricelli fu trattenuto in Firenze e onorato, <lb/>ad insinuazione di Andrea Arrighetti, di un duplice ufficio; di quello <lb/>di Filosofo e matematico del Granduca Ferdinando II, e dell'altro <lb/>di Lettore di Matematiche nel pubblico Studio fiorentino. </s>

<s>Ai due <lb/>speciali ufficii corrispose con opere, diverse di natura e di successo. </s>

<s><lb/>Come professore di Matematiche raccolse in un volume, sotto il <lb/>titolo di <emph type="italics"/>Opere geometriche,<emph.end type="italics"/> ci&ograve; che aveva speculato cos&igrave; intorno <lb/>alle propriet&agrave; della sfera e dei solidi sferali, come intorno al moto <lb/>de'gravi solidi e liquidi naturalmente discendenti e proietti, e con&shy;<lb/>tiene quel volume, pubblicato in Firenze nel 1644, tutto ci&ograve; che <lb/>vide la pubblica luce vivente l'Autore. </s></p><p type="main">

<s>Tutte le altre scritture rimaste inedite pervennero, alla morte <lb/>del Torricelli avvenuta nel 1647, dopo soli 39 anni di vita, nelle <lb/>mani di Lodovico Serenai, che, copiate in gran parte le consegn&ograve; <lb/>al Viviani, affinch&egrave; le ordinasse per dare alle stampe. </s>

<s>L'accusa <lb/>mossagli poi dal Nelli e ripetuta da altri, di non aver adempiuto <lb/>per invidia al pietoso amichevole ufficio, parr&agrave; ingiustissima a tutti <lb/>coloro, i quali sanno come il Viviani, e per la mal ferma salute e <lb/>per i pubblici impieghi, fosse impedito di pubblicare le molte opere <lb/>sue proprie. </s></p><p type="main">

<s>Le Lezioni Accademiche del Torricelli, alcune delle quali trattan <lb/>soggetti di Meccanica e di Fisica, importantissimi, ignote a quel che <lb/>che sembra al Borelli, ma vedute gi&agrave; dal Viviani, furono pubbli-<pb xlink:href="020/01/200.jpg" pagenum="181"/>cate, per la prima volta nel 1715, da Tommaso Bonaventuri, e le <lb/>varie Scritture sopra le Chiane capitate, dopo varie vicende, alle <lb/>mani del p. </s>

<s>Guido Grandi, s'inserirono, nel 1768, nella Raccolta <lb/>fiorentina degli Autori, che trattano del moto delle acque. </s></p><p type="main">

<s>Come Filosofo e Matematico del Granduca Ferdinando II, il <lb/>Torricelli, infino dal 1642, dette opera a istituire la sperimentale <lb/>Accademia Medicea, nella quale, quasi con mano ostetricante, si <lb/>estraevano dalle Opere di Galileo esperienze e invenzioni di strumenti <lb/>nuovi, da scoprir le pi&ugrave; recondite cause di tanti effetti della Natura. </s>

<s><lb/>Dicemmo che cos&igrave; fatti studi ed esercizi sperimentali, com'erano <lb/>in soggetto diverso, cos&igrave; ebbero diverso successo da quegli altri <lb/>studi, che fece lo stesso Torricelli come pubblico professore, per&shy;<lb/>ciocch&egrave; questi furono principalmente di argomento geometrico, e <lb/>andarono sotto il nome del loro proprio Autore, mentre l'espe&shy;<lb/>rienze fatte e gli strumenti inventati e costruiti nel palazzo dei Pitti, <lb/>s'attribuirono, per cortigiano ossequio, al granduca Ferdinando. </s></p><p type="main">

<s>Che sia andata veramente la cosa a questo modo, non par che <lb/>ci sia bisogno di troppo lunghe parole a provarlo, e perci&ograve;, ammesso <lb/>che le belle esperienze e gli utili strumenti attribuiti al Granduca, <lb/>fossero veramente opera e studio del Torricelli, vediamo quali fos&shy;<lb/>sero quelle particolari esperienze e quelle invenzioni, primaticci <lb/>frutti della nascente Accademia sperimentale di Firenze. </s></p><p type="main">

<s>Si disse che il Torricelli ostetric&ograve; i suoi parti sperimentali dalle <lb/>Opere di Galileo, a conferma di che, occorre prima di tutto a notar <lb/>l'origine di quei vari strumenti inventati. </s>

<s>Son questi principalmente <lb/>il Termometro a liquido, l'Igrometro a condensazione, e varie sorta <lb/>d'Idrostammi o pesa liquori, che furono poi tutti diligentemente <lb/>descritti nel libro dei Saggi di Naturali esperienze. </s>

<s>Ma che essi <lb/>appartengano veramente a questi primordii dell'Accademia Medicea, <lb/>si argomenta da quel <emph type="italics"/>Registro di varie Esperienze fatte e osservate <lb/>dal Serenissimo Granduca Ferdinando II<emph.end type="italics"/> che redatto da Paolo Mi&shy;<lb/>nucci, e copiato poi dal Viviani, fu inserito nella prima carta del <lb/>primo Tomo dei Manoscritti del Cimento, e pubblicato dal Targioni. </s>

<s><lb/>Il primo concetto di quella importantissima trasformazione del Ter&shy;<lb/>mometro ad aria, nello strumento perpetuo che, secondo si legge <lb/>nel citato Registro, <emph type="italics"/>dimostra la differenza di caldo e freddo dell'aria <lb/>e de'liquidi,<emph.end type="italics"/> sovvenne senza dubbio al Torricelli da quella espe&shy;<lb/>rienza della caraffa col collo assai lungo, empiuta d'acqua insino <lb/>al collo, e messa al fuoco, che si legge nella <emph type="italics"/>Risposta a Lodovico <lb/>delle Colombe.<emph.end type="italics"/> L'Igrometro a condensazione, di cui dava notizia lo <pb xlink:href="020/01/201.jpg" pagenum="182"/>stesso Torricelli a Michelangiolo Ricci, (tanto &egrave; vero che l'inven&shy;<lb/>zione &egrave; sua e non del Granduca) occorse facilmente all'inventore, <lb/>a fin di decidere la questione che s'agita, fra le tante, nella citata <lb/>Risposta al Colombo, se cio&egrave; quella rugiada, che si depone sulla <lb/>superficie dei corpi divenuti pi&ugrave; freddi dell'ambiente, sia aria tra&shy;<lb/>sformata nell'elemento dell'acqua. </s>

<s>I densimetri poi torricelliani, di <lb/>che il Serenissimo si serviva per riconoscer le qualit&agrave; delle varie <lb/>acque sorgenti, e per distinguer le varie bont&agrave; dei vini, scaturirono <lb/>senza dubbio dal primo Dialogo delle Due Nuove Scienze, dove <lb/>Galileo propone d'immergere una palla di cera, per conoscer negli <lb/>usi medici i vari gradi della gravit&agrave; o leggerezza dell'acqua. </s></p><p type="main">

<s>Anzi ebbero di qui origine quelle belle e feconde esperienze <lb/>delle palline di vetro vuote e galleggianti dentro un bocciol pieno <lb/>d'acqu&agrave;, che il Torricelli mostrava al Moncony, primo tra'francesi <lb/>a testimoniare nelle scienze sperimentali il primato dell'Italia. </s>

<s>Co&shy;<lb/>teste palline dettero occasione a scoprire altri fatti idrostatici curiosi <lb/>e nuovi, che si mandarono a risolvere ai varii dotti, sotto le velate <lb/>forme di problemi, per cui non fa maraviglia che, venuti a notizia <lb/>del Cartesio, o egli si appropriasse o altri spontaneamente gli attri&shy;<lb/>buissero quegli idrostatici giochetti. </s>

<s>Giochetti non furon per&ograve; alle <lb/>mani del Torricelli, che, dal veder variare il modo del galleggia&shy;<lb/>mento di quelle palline, al vario premer col dito l'aria alla bocca <lb/>del vaso, ebbe i primi indizii del variar della pressione atmosferica: <lb/>giochetti non furono alle mani del Magiotti, che di li prese occa&shy;<lb/>sione a dimostrar la verit&agrave; di quell'importantissimo fatto idrostatico <lb/>delle pressioni dei liquidi per tutti i versi, e della instantanea dif&shy;<lb/>fusione dei loro moti. </s></p><p type="main">

<s>Quel Moncony, di cui si diceva, rec&ograve; d'Italia in Francia, e anzi <lb/>trasport&ograve; seco ne'suoi viaggi in Egitto, uno de'pi&ugrave; squisiti canoc&shy;<lb/>chiali che fossero usciti dalle mani del Torricelli, giacch&egrave;, a questi <lb/>primordii o primo periodo della sperimentale Accademia fiorentina, <lb/>appartiene altres&igrave; il perfezionamento del Canocchiale galileiano e <lb/>del Microscopio. </s>

<s>Anzi, il Microscopio, cos&igrave; detto <emph type="italics"/>della perlina,<emph.end type="italics"/> che <lb/>trov&ograve; poi tanto facile accoglienza in Olanda, &egrave; invenzione tutta pro&shy;<lb/>pria del Torricelli e noi diremo a suo luogo il modo, ch'ei teneva <lb/>facilissimo di fabbricar questo, che par, fra gli strumenti di ottica, <lb/>un balocco, ma che &egrave; pure di grandissimo effetto. </s></p><p type="main">

<s>Notabile &egrave; per&ograve; che il costruttore e l'inventore di questi cos&igrave; <lb/>squisiti ottici strumenti non pensasse d'applicarli o alle osservazioni <lb/>naturali o alle celesti. </s>

<s>Vero &egrave; bene che, in questi stessi tempi della <pb xlink:href="020/01/202.jpg" pagenum="183"/>sperimentale Accademia fiorentina, si riscontrarono i moti dei sa&shy;<lb/>telliti di Giove sulle Effemeridi, che mandava il Renieri, ma forse <lb/>que'riscontri eran fatti, per ordine del principe Leopoldo, dal Vi&shy;<lb/>viani. </s>

<s>Il Torricelli pare che non fosse molto inclinato a cos&igrave; fatti <lb/>esercizi, e in ogni modo, bench&egrave; gareggiasse col Fontana e si van&shy;<lb/>tasse di aver superato in perfezione i canocchiali di lui, non fece, <lb/>in Astronomia, nessuna scoperta. </s>

<s>Nella Primavera del 1647 racconta <lb/>al Renieri come gli occorresse di veder Mercurio in congiunzione <lb/>con Venere &ldquo; e cos&igrave; all'improvviso, sul campanile del Duomo, di&shy;<lb/>scorrendo con alcuni giovani, che erano meco, feci un certo calco&shy;<lb/>laccio, per la prima volta che avevo veduto Mercurio, e conietturai <lb/>che egli di diametro reale fosse meno di otto miglia delle nostre &rdquo; <lb/>(MSS. Gal. </s>

<s>Dis. </s>

<s>T. XL, c. </s>

<s>13). </s></p><p type="main">

<s>Alla morte del Torricelli, sopravvenuta inaspettatamente nel&shy;<lb/>l'anno stesso in cui scriveva queste parole, non cess&ograve; nel Granduca <lb/>Ferdinando il prnrito, e nel principe Leopoldo quella nobile e gen&shy;<lb/>tile predilezione, che egli ebbe sempre per le scienze sperimentali. </s>

<s><lb/>A tale servizio in corte fu sostituito quel Vincenzio Viviani, che si <lb/>soleva chiamar l'ultimo, ma il pi&ugrave; affezionato dei discepoli di Ga&shy;<lb/>lileo. </s>

<s>Che egli fosse anzi svisceratamente affezionato, lo dimostr&ograve; <lb/>nello zelo dell'illustrarne e diffonderne le dottrine, come, e anco <lb/>pi&ugrave;, in sostener l'onore e rivendicarne i diritti delle scoperte. </s>

<s>Fanno <lb/>al proposito le seguenti relazioni, che dava a un amico: &ldquo; Le dir&ograve; <lb/>ancora come tra quelle povere fatiche di matematica abbozzate da <lb/>me, dal 1639 fin al 1644, quando per servizio attuale del Serenis&shy;<lb/>simo G. D. mio Signore convennemi abbandonare s&igrave; fatti studi, io <lb/>pensavo di fare scelta di quella, che ne'continui impieghi e con la <lb/>poca salute che io mi trovavo, mi fosse stata di pi&ugrave; facile esecu&shy;<lb/>zione. </s>

<s>Questa era l'illustrazione e promozione delle opere di Galileo <lb/>mio Maestro, da accoppiarsi con la descrizione della sua vita, la quale <lb/>da ogni altro assai meglio s&igrave;, ma non gi&agrave; s&igrave; veridica n&egrave; di notizie <lb/>cos&igrave; copiosa potesse scriversi &rdquo; (MSS. Gal. </s>

<s>Disc. </s>

<s>T. CXLII, c. </s>

<s>130). </s></p><p type="main">

<s>Nonostante per&ograve; la mal ferma salute e gli impieghi, fu il Vi&shy;<lb/>viani fecondissimo nello speculare e infaticabile nell'operare. </s>

<s>A <lb/>raccogliere tutti insieme, e ad ordinare i varii teoremi, che dimostr&ograve; <lb/>e i varii problemi, che risolse intorno alle dottrine del moto, si <lb/>comporrebbe un Trattato di <emph type="italics"/>aggiunte e progressi<emph.end type="italics"/> ai Dialoghi delle <lb/>Nuove Scienze, che se cede al Torricelli nell'elegante facilit&agrave; di <lb/>dimostrare, lo supera senza dubbio nella variet&agrave; e nell'abbondanza. </s>

<s><lb/>In Idrometr&igrave;a, il Viviani fu instancabile, e d'ogni parte traspira <pb xlink:href="020/01/203.jpg" pagenum="184"/>un ardentissimo zelo di diffondere le dottrine torricelliane. </s>

<s>A lui <lb/>il principio delle velocit&agrave; proporzionali alle altezze professato dal <lb/>Castelli sembrava men vero di quel che non si concludeva dalle <lb/>teorie o si verificava nei fatti; e intorno alle controversie se l'acque <lb/>giungono allo sbocco con tutta la velocit&agrave; conveniente alla caduta, <lb/>oppur ricevano impedimento e patiscano indugio dagli attriti, la&shy;<lb/>sciato per amor della verit&agrave; da parte il suo Galileo, consentiva <lb/>pienamente coll'Arrighetti. </s>

<s>Moltissime e importantissime son l'espe&shy;<lb/>rienze fatte dal Viviani, per misurar le varie quantit&agrave; d'acqua, che <lb/>in egual tempo si raccolgono dalle varie figure delle bocche di ero&shy;<lb/>gazione, ora radenti, ora sporgenti in tubi addizionali, o brevi o <lb/>lunghi, o diritti o flessuosi. </s></p><p type="main">

<s>Il Trattato del votamento dei vasi o delle <emph type="italics"/>Clessidre,<emph.end type="italics"/> diviso in <lb/>quattro libri, col titolo un po'romantico di <emph type="italics"/>Sogno idrometrico,<emph.end type="italics"/> sa&shy;<lb/>rebbe riuscito opera insigne e da risparmiare il Trattato del Moto <lb/>delle Acque del Grandi, e di altri Autori, se avesse avuto il Nostro <lb/>il tempo e la comodit&agrave; di pubblicarlo. </s>

<s>Quest'opera, nella quale, <lb/>come si diceva dianzi, il principio torricelliano delle velocit&agrave; pro&shy;<lb/>porzionali alle radici delle altezze ha il suo ampio svolgimento e <lb/>la sua pi&ugrave; compiuta dimostrazione, con altri teoremi speculati a <lb/>solo fine di promuovere il trattato <emph type="italics"/>De motu aquarum,<emph.end type="italics"/> finiscono di <lb/>persuader coloro, che dissero temerariamente aver il Viviani tenute <lb/>per invidia e per gelosia nascoste le scritture inedite del Torricelli. </s></p><p type="main">

<s>Col segreto dello stesso Torricelli, avuto dal Granduca che lo <lb/>teneva gelosamente custodito, e con altre regole proprie apprese <lb/>dalla teoria e dalla pratica, il Viviani dava opera alla costruzione <lb/>dei canocchiali, e attendeva, ora per proprio genio, ora per parti&shy;<lb/>ticolare ordine del principe Leopoldo, alle osservazioni celesti. </s>

<s>Ma <lb/>la mal ferma salute non permettendogli le lunghe e faticose vigilie, <lb/>non fece, come il Torricelli, in Astronomia molti progressi. </s>

<s>Dei mol&shy;<lb/>tissimi per&ograve; fatti nella Fisica sperimentale diremo pi&ugrave; qua, quando <lb/>c'incontreremo un'altra volta nel Viviani come accademico del Ci&shy;<lb/>mento, ma intanto, a svolgere que'cento tanti e pi&ugrave; volumi delle <lb/>sue carte, non par possibile che un uomo, e sia pur che la vita gli <lb/>decorresse lunghissima dal 1622 al 1703 potesse attendere a tante <lb/>e s&igrave; difficili cose. </s>

<s>Stanco delle proprie speculazioni, si ricreava in <lb/>tradurre dal latino o dal francese ci&ograve; che di nuovo e di bello aves&shy;<lb/>sero speculato gli altri nei loro proprii libri; ora compendiava trat&shy;<lb/>tati intieri, forse per uso dei principi padroni, ora ne disegnava e <lb/>in parte coloriva de'nuovi, in soggetto di matematiche, di cosmo-<pb xlink:href="020/01/204.jpg" pagenum="185"/>grafia o di qualsivoglia altro. </s>

<s>&ldquo; Se io avessi, scriveva a un amico, a <lb/>cucire tutte le mie speculazioni imbastite e finire di riempir tutti i <lb/>miei orditi con obbligo ancora di non dover pensare a niun altra cosa <lb/>di nuovo, non mi sarebbe tanto il vivere fino a cent'anni, con sanit&agrave; <lb/>perfetta e disoccupazione da ogni altro impiego &rdquo; (ivi, T. CXLII, c.270). </s></p><p type="main">

<s>Quando scriveva cos&igrave;, il Viviani contava 56 anni, e non aveva <lb/>altro pubblicato che <emph type="italics"/>De maximis et minimis,<emph.end type="italics"/> la <emph type="italics"/>Scienza Universale <lb/>delle proporzioni,<emph.end type="italics"/> il <emph type="italics"/>Diporto geometrico,<emph.end type="italics"/> l'<emph type="italics"/>Enodatio problematum<emph.end type="italics"/><lb/>che son piccola parte, e non la pi&ugrave; importante delle opere di lui. </s>

<s><lb/>Il rimanente, da poche altre cose in fuori, &egrave; tuttavia inedito, e ci&ograve; <lb/>vuol dire che un dovizioso tesoro della scienza italiana &egrave; rimasto da <lb/>tanto tempo, disutile e infruttuoso. </s>

<s>A lui vecchio di settantott'anni <lb/>il p. </s>

<s>ab. </s>

<s>Grandi, scrivendogli di Roma, faceva questa domanda: <lb/>&ldquo; &Egrave; fuori voce in Roma che le opere di V. S. si ristampino in <lb/>Londra, e che que'signori della Societ&agrave; Regia abbiano impetrato <lb/>dal Serenissimo Granduca li di lei scritti, per imprimerli con altre <lb/>sue opere .... &Egrave; egli vero tuttoci&ograve;, oppure posso io seguitare ad as&shy;<lb/>sicurare l'Italia che le di lei fatiche saranno impresse per opera <lb/>del sig. </s>

<s>Panzanini? </s>

<s>&rdquo; (ivi, T. CXLVII. c. </s>

<s>189). A che il buon vecchio <lb/>cos&igrave; rispondeva: &ldquo; &Egrave; ben falsa quella voce che &egrave; fuori, perch&egrave; l'opere <lb/>di quello scimunito dolcissimo, n&egrave; per mano di lui n&egrave; di altri non <lb/>v'&egrave; apparenza che si sieno per vedere, se Dio non fa miracoli &rdquo; <lb/>(ivi, T. CXLVIII. c. </s>

<s>36). E i miracoli ancora non sono stati fatti. </s></p><p type="main">

<s>Ma passiamo a veder quel che operasse il Viviani in questo, <lb/>che da noi si distingue col nome di secondo periodo della speri&shy;<lb/>mentale Accademia medicea. </s>

<s>Soggetto principale di queste espe&shy;<lb/>rienze, che si direbbero, alla maniera dei nostri giorni, esperienze <lb/>di gabinetto, furon quelle degli agghiacciamenti dell'acque, per <lb/>veder che variet&agrave; facessero esposti i vasi in varie situazioni all'aria <lb/>aperta. </s>

<s>Cominciarono queste esperienze nel Dicembre 1648, e si <lb/>proseguirono per pi&ugrave; altre invernate successive (MSS. Cim. </s>

<s>T. I, c. </s>

<s>5, <lb/>13 ecc.). Appartengono pure a questo periodo dell'Accademia quelle <lb/>osservazioni, di non lieve importanza per la teoria della conduci&shy;<lb/>bilit&agrave; del calore, che concernono il vario tempo del consumarsi il <lb/>ghiaccio nelle varie materie, di che son formati i recipienti. </s>

<s>Di tali <lb/>osservazioni poi si fece qualche cenno anco nel Libro dei <emph type="italics"/>Saggi,<emph.end type="italics"/><lb/>ma vi si tace di un'altra esperienza, fatta pure in questo medesimo <lb/>tempo, ed &egrave; quella del traforare in vario tempo, pallottole di varia <lb/>materia e di ugual grossezza, posate sopra una larga lastra di <lb/>ghiaccio. (Targioni, Aggrandim. </s>

<s>T. II. P. II. pag. </s>

<s>164). </s></p><pb xlink:href="020/01/205.jpg" pagenum="186"/><p type="main">

<s>Oltre a queste, si fecero pure altre esperienze, che non si sa&shy;<lb/>rebbero potute praticare fra le chiuse pareti di una stanza, n&egrave; <lb/>eseguire da un osservatore solo. </s>

<s>Ed ecco di qui l'occasione e il <lb/>bisogno d'organar la sua vita in varie membra, e pigliar la Medicea <lb/>sperimentale istituzione pi&ugrave; conveniente ordine di Accademia. </s>

<s>Queste <lb/>esperienze furon quelle che si fecero, tra il 1656 e 57, intorno alle <lb/>velocit&agrave; del suono e della luce, e nelle quali, ad aiutare il Viviani, <lb/>venivan chiamati il Borelli e il Rinaldini. </s>

<s>Dall'altra parte, il bisogno <lb/>di avere, a sperimentar simili effetti naturali, strumenti e spazii che <lb/>non erano n&egrave; potevano essere di propriet&agrave; e di diritto di uomini <lb/>privati, fece sentir vivo il bisogno che la scienza aveva della pro&shy;<lb/>tezione dei principi, e ai principi stessi fece pregustar la gloria di <lb/>partecipare ai meriti scientifici dei privati. </s>

<s>D'ond'&egrave; che i consessi <lb/>scientifici, nel palazzo granducale dei Medici, passarono a pigliar <lb/>ordinamento e instituto pi&ugrave; proprio di Accademia, in un-terzo pe&shy;<lb/>riodo, che si distinse dagli altri col titolo di <emph type="italics"/>Cimento.<emph.end type="italics"/></s></p><p type="main">

<s>I principi Medicei, dai quali invocava la scienza i validi aiuti, <lb/>erano il granduca Ferdinando II e Leopoldo fratello di lui. </s>

<s>Che <lb/>fosse Ferdinando inclinato a favorire gli studi sperimentali, lo pro&shy;<lb/>verebbe, senz'altro, l'essersi egli ingerito nell'invenzione di quegli <lb/>strumenti, che certamente &egrave; dovuta al Torricelli. </s>

<s>Ma pur di qui <lb/>s'argomenta che predominasse in lui all'ingegno la curiosit&agrave; e <lb/>l'ambizione. </s>

<s>Dall'altra parte chi aveva largamente speso per far <lb/>quelle esperienze, e per eseguire quegli strumenti, pareva in certo <lb/>modo che avesse il diritto di usarli per se, di dirli o di farli dir <lb/>suoi. </s>

<s>In seguito, se ced&egrave; alquanto nell'animo suo l'ambizione, non <lb/>cess&ograve; per questo la curiosit&agrave;, o una certa sua particolar prurigine <lb/>di sapere. </s>

<s>Noi, non potremmo in altro miglior modo rappresentare <lb/>ai lettori o qualificare quella curiosit&agrave; granducale, che per la se&shy;<lb/>guente scenetta, colorita da noi su una nota, che si legge a carte 120 <lb/>del X Tomo dei Manoscritti del Cimento. </s></p><p type="main">

<s>La sera del di 5 Dicembre 1665, a qualche ora di notte, una <lb/>carrozza di corte si ferma dinanzi alla porta di casa del Viviani. </s>

<s><lb/>Scende uno staffiere, entra: &mdash; Sor Vincenzio, il Padron Serenissimo <lb/>l'attende a palazzo &mdash; E il signor Vincenzio vestirsi, entrare in car&shy;<lb/>rozza, scendere nel cortile, e su per lo scalone dei Pitti. </s>

<s>Francesco <lb/>Redi l'introduce in camera: il Granduca era a letto. </s>

<s>&mdash; V'ho man&shy;<lb/>dato a chiamare, dice il Serenissimo, sollevandosi sulle coltri e <lb/>accennando alla fiamma del camminetto, per saper da voi in che <lb/>maniera, dagli spiragli della porta di camera e della finestra, bench&egrave; <pb xlink:href="020/01/206.jpg" pagenum="187"/>il tutto serrato, entri in camera vento, come si manifesta dal veder <lb/>muoversi indentro la fiammella di una candela: e perch&egrave; sia la <lb/>stessa fiammella con gran velocit&agrave; rapita, accostatala agli spiragli <lb/>dell'asse del cammino. </s>

<s>&mdash; </s></p><p type="main">

<s>Il principe Leopoldo aveva della scienza pi&ugrave; nobili e dignitosi <lb/>sentimenti, e se la sua condizione non rendesse difficile il farne la <lb/>giusta stima, diremmo che aveva altra cultura scientifica e altra <lb/>forza d'ingegno. </s>

<s>Difficile &egrave; il farne la giusta stima, perch&egrave; alcune <lb/>speculazioni e scoperte si dubita che sieno attribuite a lui dall'os&shy;<lb/>sequio e dalla adulazione. </s>

<s>Cos&igrave;, per citare un esempio, la causa del <lb/>cos&igrave; detto <emph type="italics"/>salto dell'immersione<emph.end type="italics"/> osservato nelle caraffe a lungo collo <lb/>ripiene d'acqua e sommerse nella neve, il Borelli, con tutti gli altri, <lb/>dice essere stata investigata e scoperta dal Principe, quando per&ograve; <lb/>discorre con lui e gli scrive in lettere familiari. </s>

<s>Ma liberato poi da <lb/>ogni servit&ugrave; cortigianesca, dice francamente, nel libro <emph type="italics"/>De motioni&shy;<lb/>bus natural.<emph.end type="italics"/> del salto dell'immersione: &ldquo; Ego animadverti et docui <lb/>hoc contingere a restrictione eiusdem vasis &rdquo; (Regio Julio 1670, <lb/>pag. </s>

<s>547). </s></p><p type="main">

<s>Ma pure, la giudiziosa critica fatta dal Principe ad alcune spe&shy;<lb/>culazioni, come sarebbe giusto quella dello stesso Borelli concer&shy;<lb/>nente le cause del variar la pressione ammosferica, quando il tempo <lb/>si dispone o si scioglie in pioggia, e come sarebbe l'altra con la <lb/>quale il Renieri, per similitudine della varia disposizione delle lenti <lb/>nel canocchiale, spiegava il ricrescer l'apparente figura degli astri, <lb/>giunti vicino a toccar l'orizzonte; mentre rivelano una non ordi&shy;<lb/>naria acutezza d'ingegno, rendon nel medesimo tempo bella testi&shy;<lb/>monianza di quel modesto riserbo, con cui il Principe stesso entrava <lb/>nel pericolo di quelle scientifiche discussioni. </s></p><p type="main">

<s>Quel che per&ograve; abbiam per certissimo, &egrave; che in mezzo ai pia&shy;<lb/>ceri e agli svaghi di una splendida corte, attese con grande amore <lb/>agli studii matematici, infino da giovanetto. </s>

<s>Di ventun'anno faceva <lb/>richiedere a Galileo la dimostrazione allora allora trovata dal famoso <lb/>supposto meccanico, per mezzo del suo precettore don Famiano Mi&shy;<lb/>chelini, il quale cos&igrave; scriveva al medesimo Galileo: &ldquo; Il Serenissimo <lb/>ha di gi&agrave; visti i sei libri di Euclide e di presente vede l'undecimo, <lb/>e il detto libro del Moto (i Dial. </s>

<s>delle Due N. S.) con pensiero di <lb/>veder prima le Opere di V. S. </s>

<s>Molto Illustre ed Eccellentissima e <lb/>poi il resto dei matematici &rdquo; (MSS. Gal. </s>

<s>Div. </s>

<s>II. P. VI. T. XIII. c. </s>

<s>112). </s></p><p type="main">

<s>L'anno dopo, avendo Fortunio Liceti gi&agrave; pubblicato il suo libro <lb/><emph type="italics"/>De Lapide bononiensi,<emph.end type="italics"/> nel capitolo L, del quale, contro le dottrine <pb xlink:href="020/01/207.jpg" pagenum="188"/>di Galileo, attribuiva il color cinereo della Luna a un fenomeno di <lb/>fosforescenza, il principe Leopoldo, nel dar relazione del nuovo libro <lb/>peripatetico, sollecita Galileo stesso a difender le sue dottrine, ci&ograve; <lb/>che egli poi fece in quella Lettera sul Candore lunare, che &egrave; una <lb/>delle pi&ugrave; belle scritture astronomiche del nostro Autore. </s>

<s>Di questa <lb/>lettera, scrivendo il giovane principe Leopoldo da Siena, il d&igrave; 14 <lb/>maggio 1640, diceva a Galileo: &ldquo; Io, tra le altre cose che in essa <lb/>sono, ho ammirato quella di dimostrare, bench&egrave; tanto lontani dalla <lb/>Luna, che il lume in essa riflesso dalla Terra sia maggiore del <lb/>nostro lume crepuscolino, e in conseguenza di quello che la me&shy;<lb/>desima Luna sopra di noi riflette. </s>

<s>E perch&egrave; io non posso godere e <lb/>cavar quel frutto che desidererei dalla conversazione sua, cerco di <lb/>trattenermi e di ammaestrarmi in qualche parte, nel leggere le sue <lb/>Opere. </s>

<s>E per&ograve;, avendo finito di scorrere l'undecimo e duodecimo <lb/>di Euclide, sto vedendo adesso il suo Libretto delle Galleggianti, <lb/>parto non meno degli altri degno del suo intelletto, soggiungendole <lb/>che far&ograve; ancora un poco di sessione con Mons. </s>

<s>Arcivescovo Picco&shy;<lb/>lomini, tanto affezionato a V.S. e alle cose sue, dove si legger&agrave; la <lb/>scrittura sopra il lume secondario della Luna. </s>

<s>Spero io d'esser poi <lb/>da lei in questa state dove discorrer&ograve; seco di alcune cose, che mi <lb/>sono sovvenute in diverse materie, non lo potendo tanto bene fare <lb/>con la penna, quanto con la voce &rdquo; (MSS. Gal. </s>

<s>Disc. </s>

<s>T. CXLVIII. <lb/>c. </s>

<s>37). E venuta l'estate non manc&ograve; il giovane Principe di scender <lb/>dalle splendide sale dei Pitti, per salir su al tugurio di Arcetri, a <lb/>trattenervisi col venerando vecchio che l'abitava in scientifici col&shy;<lb/>loqui. </s>

<s>Frutto di quei colloqui fu la chiamata del Torricelli a Firenze, <lb/>da cui ebbe principio, come si vide, la sperimentale Accademia <lb/>Medicea, e d'onde s'avviarono a istituirsi quegli altri celebri con&shy;<lb/>sessi accademici detti del Cimento, ai quali convien che si rivolga <lb/>il nostro Discorso. </s></p><p type="main">

<s><emph type="center"/>VIII.<emph.end type="center"/></s></p><p type="main">

<s>Incominciarono quei consessi nel mese di Giugno del 1657, e <lb/>i primi e principali collaboratori all'esperienze naturali che vi si <lb/>fecero, furon quei tre, che vedemmo esercitarsi in Firenze e in <lb/>Pisa intorno al misurare la velocit&agrave; della luce e del suono. </s>

<s>Pare <lb/>che, anche in questo nuovo ordinamento, il Viviani serbi una certa <pb xlink:href="020/01/208.jpg" pagenum="189"/>preminenza, che giustamente gli &egrave; attribuita, s&igrave; per essere stato col&shy;<lb/>lega e successore al Torricelli in quell'ufficio, e s&igrave; per lo zelo, per la <lb/>dottrina, e per l'operosit&agrave; con cui, da parecchi anni, l'aveva esercitato. </s></p><p type="main">

<s>Gian Alfonso Borelli, chiamato di Messina a professare le Ma&shy;<lb/>tematiche nello studio pisano, aveva fin d'allora dato saggio del&shy;<lb/>l'acume e della novit&agrave; delle sue speculazioni, non che di un'arte <lb/>squisitissima di sottoporle al cimento. </s>

<s>Tutti gli studii sperimentali <lb/>di lui, anche in apparenza pi&ugrave; disparati, convenivano in un unica <lb/>intenzione, che era quella di applicar la Meccanica e la Fisica al <lb/>moto degli animali. </s>

<s>Si preparava perci&ograve; il nostro Autore a scrivere <lb/>il celeberrimo Trattato con due libri, uno di Meccanica, intitolato <lb/><emph type="italics"/>De vi percussionis,<emph.end type="italics"/> pubblicato nel 1667, e l'altro col titolo <emph type="italics"/>De mo&shy;<lb/>tionibus naturalibus,<emph.end type="italics"/> pubblicato nel 1670, quasi lemmi premessi <lb/>alla grande Opera <emph type="italics"/>De motu animalium.<emph.end type="italics"/> Alle osservazioni naturali, <lb/>che bisognavano a condurla, attendeva gi&agrave; da lungo tempo, e il d&igrave; <lb/>16 Marzo 1663 pregava per mezzo del Michelini, che il principe <lb/>Leopoldo si compiacesse di farlo venire a Livorno, per <emph type="italics"/>far espe&shy;<lb/>rienze sui pesci vivi, per capire perfettamente come si muovono e <lb/>nuotano i pesci<emph.end type="italics"/> (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XVII. c. </s>

<s>188). Sotto il di 6 d'Aprile <lb/>1665, scriveva direttamente al Principe che era entrato a specular <lb/>la natura e la propriet&agrave; della percossa, intorno alla quale il gran <lb/>Galileo nulla aveva lasciato in iscritto (ivi, T. XVIII. c. </s>

<s>152), prepa&shy;<lb/>randosi cos&igrave; a distendere il primo libro da premettersi al Trattato <lb/>dei Moti animali. </s>

<s>Quattro anni dopo, nel Luglio, scriveva allo stesso, <lb/>rendendogli conto cos&igrave; de'suoi studi: &ldquo; Ho gi&agrave; all'ordine questo <lb/>secondo Tomo pur preparatorio della materia principale. </s>

<s>Tratto in <lb/>questo dei moti naturali dipendenti dalla gravit&agrave; &rdquo; (ivi, T. XIX, <lb/>c. </s>

<s>263) e verso la met&agrave; d'Aprile del 71: &ldquo; Spero poi questa state <lb/>perfezionare il terzo libro della immensa forza de'muscoli con le <lb/>sue cause meccaniche dimostrate, cosa affatto nuova. </s>

<s>Appresso rac&shy;<lb/>corr&ograve; in un altro libro tutto il resto di questa ammirabile Filosofia &rdquo; <lb/>(ivi, T. XX, c. </s>

<s>49). E infatti, mantenuto il proposito, torna a scri&shy;<lb/>vere sotto il d&igrave; 22 Luglio &ldquo; porr&ograve; mano subito allo stampa del mio <lb/>libro della forza dei muscoli, il quale &egrave; ridotto quasi a perfezione &rdquo; <lb/>(ivi, c. </s>

<s>65). Le pubbliche e private sventure per&ograve; non permisero al <lb/>Borelli di mandare ad effetto cos&igrave; questo proposito, com'avea man&shy;<lb/>dato quello, e la prima parte della grande Opera, dove si tratta <lb/>della forza immensa dei muscoli, fu pubblicata postuma in Roma <lb/>nel 1680: l'altra parte, dove si tratta il resto di quella ammirabile <lb/>Filosofia, vide ivi pure la luce nell'anno dopo. </s></p><pb xlink:href="020/01/209.jpg" pagenum="190"/><p type="main">

<s>Dicemmo che, a specular questa Filosofia, la quale fu poi ve&shy;<lb/>ramente riconosciuta da tutti per ammirabile e nuova, concorrevano <lb/>nell'intenzion dell'Autore gli studi pi&ugrave; varii della sua vita. </s>

<s>E in&shy;<lb/>fatti, quando, venutagli occasione d'appuntare in Giove uno squi&shy;<lb/>sitissimo canocchial del Campani, si trov&ograve; senza volere implicato <lb/>negli studii astronomici, frutto de'quali fu l'Opera insigne <emph type="italics"/>Theo&shy;<lb/>ricae Mediceorum,<emph.end type="italics"/> cos&igrave; nel pubblicare il libro scriveva il Borelli <lb/>al Lettore: &ldquo; Erit igitur huiusmodi opusculum non interruptio mei <lb/>prioris instituti, sed veluti parenthesis quaedam meorum studiorum, <lb/>nam denuo ad intermissum opus De motu anim. </s>

<s>redii &rdquo; (Floren&shy;<lb/>tiae, 1665, pag. </s>

<s>VII). Figuriamoci quel che dee essere il periodo, se <lb/>la Teorica de'pianeti medicei, che &egrave; il preludio alla nuova Astrono&shy;<lb/>mia neutoniana, non &egrave; che una parentesi! Parentesi, nella quale, <lb/>come inciso, concludesi la teoria planetaria delle comete. </s>

<s>La for&shy;<lb/>tezza di S. </s>

<s>Miniato al Monte era la specula, dove il Borelli faceva <lb/>le sue osservazioni, e dov'egli aveva erette quelle macchine, a di&shy;<lb/>mostrare il viaggio parabolico descritto da que'corpi celesti creduti <lb/>vagabondi per lo spazio e senza leggi. </s>

<s>Gli strumenti, che adorna&shy;<lb/>vano le stanze di S. </s>

<s>Miniato sopra Firenze, primo osservatorio astro&shy;<lb/>nomico d'Italia, eran lavorati con semplicit&agrave;, ed eran pure tanto <lb/>precisi. </s>

<s>&ldquo; Ho fatto, con grandissimo frutto, scriveva al principe Leo&shy;<lb/>poldo, fabbricare un istrumento da servir di sestante, il cui semi&shy;<lb/>diametro sar&agrave; 5 braccia. </s>

<s>&Egrave; composto di semplici regoli, facilissimo <lb/>a fabbricarsi ed adoperarsi, col quale spero di fare osservazioni cos&igrave; <lb/>squisite, come coloro che spendono centinaia di scudi in simiglianti <lb/>strumenti &rdquo; (ivi, T. XVIII. c. </s>

<s>154). </s></p><p type="main">

<s>Gli strumenti e l'esperienze del Torricelli, nel primo periodo <lb/>dell'Accademia Medicea, vedemmo essere un frutto allegato nel fiore <lb/>delle opere di Galileo: anco l'esperienze intorno alle quali, nel se&shy;<lb/>condo periodo, si travagli&ograve; il Viviani, per decidere se la luce si <lb/>muove in tempo, non avevano altra intenzione, che di mandare ad <lb/>effetto un pensiero proposto nel I Dialogo delle Due Nuove Scienze. </s>

<s><lb/>N&egrave; il Borelli, a ricercar le tradizioni della scienza galileiana, fu <lb/>punto inferiore agli stessi suoi colleghi. </s>

<s>Molte delle Scritture del <lb/>gran Maestro, come sarebbero le Tavole de'moti medii dei satelliti <lb/>di Giove, l'Istruzione intorno al modo d'usar lo strumento nelle <lb/>osservazioni gioviali, il Discorso dell'ufficio meccanico del timone <lb/>nel diriger le navi, e altre scritture galileiane, delle quali s'&egrave; perduta <lb/>la copia e l'originale, rivivono nelle opere o manoscritte o stam&shy;<lb/>pate dello stesso Borelli. </s></p><pb xlink:href="020/01/210.jpg" pagenum="191"/><p type="main">

<s>Quel che egli poi, per far progredire le dottrine sperimentali, <lb/>conforme ai metodi di Galileo, operasse in questo terzo periodo <lb/>dell'Accademia Medicea, o del Cimento, l'abbiamo diligentemente <lb/>annoverato da lui medesimo, nel libro <emph type="italics"/>De motionibus naturalibus,<emph.end type="italics"/><lb/>nello scrivere il quale, anzi, secondo che egli stesso dichiara, ebbe <lb/>questa particolare intenzione. </s>

<s>Accennando ivi al fatto della bilancia <lb/>equilibrata, che riscaldando l'aria ambiente a un de'piattelli tra&shy;<lb/>bocca dall'altra parte, soggiunge: &ldquo; Rationem huius admirabilis <lb/>effectus excogitavi et amico petenti reddidi, eamque communicavi <lb/>Societati doctissimorum virorum a Sereniss. </s>

<s>et Eminentiss. </s>

<s>Cardi&shy;<lb/>nali Leopoldo Mediceo erectam, quam deinceps more italico Aca&shy;<lb/>demiam experimentalem mediceam vocabo &rdquo; (Regio Julio 1670, <lb/>pag. </s>

<s>126). Di quel gentile esperimento del fumo, che discende nel <lb/>vuoto torricelliano, dice &ldquo; quod Florentiae Serenissimo Leopoldo <lb/>cardinali mediceo communicavi &rdquo; (ivi, pag. </s>

<s>128) e il medesimo dice <lb/>pure di quel barometro a sifone, di cui &ldquo; ichon habetur fig. </s>

<s>34 libri <lb/>Experimentorum eiusdem Academiae &rdquo; (ivi, pag. </s>

<s>209). </s></p><p type="main">

<s>De'varii modi per trovare il peso specifico dell'aria proposti <lb/>nell'Accademia, ne commemora &ldquo; aliquos ex multis a me ibidem <lb/>propositi &rdquo; (ivi, pag. </s>

<s>247) e son quegli ingegnosi strumenti chiamati <lb/>da lui <emph type="italics"/>Termostatici,<emph.end type="italics"/> all'invenzion dei quali aveva pensato infino <lb/>dal 1656 (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XVII. c. </s>

<s>1). &ldquo; Sed praecipuus ac pul&shy;<lb/>cherrimus modus experiendi aeris gravitatem hic est, quem Aca&shy;<lb/>demiae medicaee experimentali anno 1660 comunicavi una cum <lb/>eius demonstratione &rdquo; (De mot. </s>

<s>nat. </s>

<s>pag. </s>

<s>251). Nella stessa Acca&shy;<lb/>demia dice pure d'aver dimostrato con innumerevoli esperimenti <lb/>che il ghiaccio occupa maggiore spazio dell'acqua liquida; &ldquo; experi&shy;<lb/>menta quae omnia legi possunt in praedicto libro Experimentorum <lb/>a folio 127 usque ad fol. </s>

<s>165 &rdquo; (ivi, pag. </s>

<s>546). </s></p><p type="main">

<s>Anche il Viviani non si volle defraudare della sodisfazione di <lb/>dire quel che egli oper&ograve; nell'Accademia, e ci&ograve; fece palese, non al <lb/>pubblico, ma in una nota autografa, che si legge a c. </s>

<s>259 del Tomo X <lb/>dei MSS. del Cimento, e che poi il Nelli pubblic&ograve; nel suo Saggio <lb/>di Storia Letteraria (Lucca 1759, pag. </s>

<s>110, 11). &ldquo; Miei sono, lasci&ograve; <lb/>ivi iscritto il Viviani, I. </s>

<s>Li tre strumenti, per provar la pressione <lb/>dell'aria e che mancando quella il mercurio e l'acqua discendono <lb/>in qualunque cannello. </s>

<s>II. </s>

<s>Miei sono li cinque strumenti per pro&shy;<lb/>vare la costituzione dell'aria bassa ed alta. </s>

<s>III. </s>

<s>Mio lo strumento <lb/>cilindrico con la canna dentro, per esaminar la gravezza in specie <lb/>dei fluidi. </s>

<s>IV. </s>

<s>Mia la scatola per le rifrazioni de'fluidi. </s>

<s>V. </s>

<s>Miei li <pb xlink:href="020/01/211.jpg" pagenum="192"/>due strumenti per conoscere la gravit&agrave; in specie dei fluidi e dei <lb/>metalli. </s>

<s>VI. </s>

<s>Mie l'osservazioni circa l'ondata de'fluidi nei sifoni. </s>

<s><lb/>VII. </s>

<s>Mia l'osservazione de'balzi delle galleggianti. </s>

<s>VIII. </s>

<s>Mio il con&shy;<lb/>cetto dell'equabilit&agrave; de'suoni e dei loro usi. </s>

<s>IX. </s>

<s>Mio il nuovo modo <lb/>di misurar le distanze senza la vampa. </s>

<s>X. </s>

<s>Mie l'osservazioni in&shy;<lb/>torno l'ambra. </s>

<s>XI. </s>

<s>Miei li due strumenti per conoscer se l'alzar <lb/>dell'acqua nei cannellini proceda dalla pressione dell'aria ambiente <lb/>con succhiar collo schizzatoio. </s>

<s>XII. </s>

<s>Mie l'esperienze due proposte <lb/>per invalidar la detta pressione attorno li cannellini. </s>

<s>XIII. </s>

<s>Miei li <lb/>due strumenti intorno la pressione dell'acqua. </s>

<s>XIV. </s>

<s>Mia l'osser&shy;<lb/>vazione che tutti i legni vanno al fondo nell'acqua (provar se nel&shy;<lb/>l'olio). XV. </s>

<s>Mio lo strumento per aver la lunghezza de'pendoli di <lb/>desiderata durazione. </s>

<s>XVI. </s>

<s>Mio lo strumento a palla, per la gravit&agrave; <lb/>in specie de'fluidi col mettere i pesi dentro la palla. </s>

<s>&rdquo; Quest'ultimo <lb/>strumento, da cui si son trasformati gli Areometri moderni, come <lb/>quello pure annoverato qui in III luogo, sono illustrati con abbozzi <lb/>di figure, che suppliscono a una lunga e minuta descrizione, nel <lb/>seguente T. XI dei Manoscritti sopra citati a carte 101 e 105. </s></p><p type="main">

<s>Dopo essersi presa cos&igrave; la sua porzione ciascuno di que'due <lb/>validi commensali, si vede bene che la tavola riman quasi sparec&shy;<lb/>chiata, e che non resta, se non che poco o nulla a quegli altri, ivi <lb/>attorno seduti. </s>

<s>Fra questi occorre primo a riguardare Carlo Rinal&shy;<lb/>dini, che, messogli innanzi, non saprebbe in coscienza a che stender <lb/>la mano per prenderlo e tenerlo per suo. </s>

<s>Vero &egrave; che egli afferma <lb/>l'esperienza dell'anello riscaldato, a verificar se i solidi si dilatano al <lb/>calore, essere stata proposta da s&egrave; nell'Accademia (ivi, T. XXIV. c. </s>

<s>24) <lb/>ma tessendo e ritessendo le speculazioni del proprio cervello colla <lb/>pretensione di farle valere, eziandio contro la verit&agrave; dei fatti, non <lb/>riusc&igrave; ad altro che a far perdere la pazienza al Borelli e al Viviani. </s></p><p type="main">

<s>Un'altra volta s'era messo in testa che il tuonar di un can&shy;<lb/>none tanto pu&ograve; corresse veloce, quanto in maggior numero vi fos&shy;<lb/>sero accesi dentro i granelli della polvere. </s>

<s>Il Borelli dimostr&ograve; di <lb/>fatto, alla presenza del Granduca sulla Piazza dei Pitti, che i tuoni <lb/>si propagavano colla stessa velocit&agrave; da una piccola spingarda e da <lb/>un grosso cannone. </s>

<s>Il Rinaldini disse allora che ci&ograve; seguiva perch&egrave; <lb/>le bocche erano rivolte verso il Palazzo, e il Granduca subito mand&ograve; <lb/>due lacch&egrave;, che volgessero i pezzi da lato, e nonostante anco questa <lb/>volta i tuoni arrivarono alle solite distanze, in tempi misurati dalle <lb/>vibrazioni del pendolo sempre esattamente uguali. </s></p><p type="main">

<s>Il Magalotti che, colla sua solita vivacit&agrave;, racconta in una sua <pb xlink:href="020/01/212.jpg" pagenum="193"/>Lettera questa storia, prosegue: &ldquo; Pure il Rinaldini, che &egrave; capo <lb/>sodo, ma sodo bene, volle che si rifacesse ieri sera con la culatta <lb/>volta al Palazzo e la bocca all'ins&ugrave;, e senza alterazione nessuna <lb/>tutti i suoni arrivarono in tempi uguali. </s>

<s>Sicch&egrave; V. S. si puole im&shy;<lb/>maginare che il poveraccio cos&igrave; cammina per Firenze che pare un <lb/>gatto bagnato dall'acqua fredda &rdquo; (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XXV, c. </s>

<s>181). <lb/>Capo sodo si mostr&ograve; pure, quando, a profondare il vasetto del mer&shy;<lb/>curio sott'acqua, disse d'aver trovato che il mercurio stesso dentro <lb/>la canna non saliva pi&ugrave; su che un braccio e un quarto; capo sodo, <lb/>quando nel livello dell'argento vivo, a pi&egrave; e in cima del campanile <lb/>di Pisa, non gli riusc&igrave; di trovarci differenza. (Ivi, T. VIII, c. </s>

<s>69). </s></p><p type="main">

<s>Bench&egrave; il Viviani scrivesse che l'impressione delle Opere di <lb/>Galileo, fatta in Bologna, era stata promossa ed ultimata per mezzo <lb/>del Rinaldini (MSS. Gal. </s>

<s>Disc. </s>

<s>T. CXLII, c. </s>

<s>3), sembra nonostante <lb/>che questi poco le avesse lette, o poco le ritenesse a memoria. </s>

<s>Co&shy;<lb/>me prova di ci&ograve; si potrebbe citare il fatto, che, avendo il Rinaldini <lb/>stesso eseguita a Livorno l'esperienza che nel medesimo tempo <lb/>giungono al piano dell'orizzonte e la palla cadente dalla bocca del <lb/>cannone e quella spinta per forza di polvere; domanda poi al Vi&shy;<lb/>viani dove Galileo tratti di questo (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XXIV. c. </s>

<s>43), <lb/>quasi che il secondo Dialogo de'due Massimi Sistemi non fosse <lb/>luogo abbastanza cospicuo. (Alb. </s>

<s>I, 172). Incerto in ogni cosa, per <lb/>la smania d'andare in cerca, non di verit&agrave; ma di novit&agrave;, pi&ugrave; che <lb/>galileiano, &egrave; aristotelico, e in ogni modo non ha saputo scoter dal <lb/>pallio filosofico la polvere appiccaticcia del Peripato. </s>

<s>A persuaderci <lb/>di ci&ograve;, basta leggere la Prefazione a quel ponderoso volume della <lb/><emph type="italics"/>Filosofia Razionale<emph.end type="italics"/> dove, dopo aver sottilmente discorso del me&shy;<lb/>todo sperimentale, e aver confessato che delle cose trattate ivi pa&shy;<lb/>recchie saranno quelle da lui attinte <emph type="italics"/>ex peripateticorum fonte,<emph.end type="italics"/> cos&igrave; <lb/>soggiunge: &ldquo; Dum interim intelligis aliquando me paululum ab <lb/>Aristotelico calle declinasse, et abiecta, quam superioribus annis <lb/>tuebar opinione, longe diversam suscepisse, non est cur de hoc tibi <lb/>admiratio incessat, neminem enim praeterit scite admodum ab an&shy;<lb/>tiquis veritatem Saturni, hoc est temporis, filiam habitam fuisse &rdquo; <lb/>(Patavii 1681, pag. </s>

<s>XII). Che fosse veramente a principio addetto <lb/>alla setta peripatetica, e che poi l'avesse talvolta abbandonata per <lb/>seguir piuttosto la retta ragione, lo dice da s&egrave; il Rinaldini, colle <lb/>seguenti parole, le quali per&ograve; non corrispondono ai fatti della sua <lb/>vita scientifica: &ldquo; Quamvis a teneris annis salebrosam philosophandi <lb/>viam calcaverim, ac animum Peripateticae doctrinae studiis mirum <pb xlink:href="020/01/213.jpg" pagenum="194"/>in modum imbuerim, me tamen nunquam veritatis amor deseruit, <lb/>quin potius illo factus ardentior, me coegit omnem auctoritatem <lb/>negligere solidasque rationes inquirere ut iis denique suffultus quod <lb/>magis rationi consentaneum est amplecti possem &rdquo; (ibi, pag. </s>

<s>314). </s></p><p type="main">

<s>Fra gli altri chiamati a partecipare ai consessi sperimentali me&shy;<lb/>dicei, s'ha memoria dei tre fratelli Del Buono: Paolo che fece le <lb/>prime esperienze sulle soluzioni dell'aria nell'acqua, e Candido e <lb/>Anton Maria, i quali immaginarono e costruirono una macchina da <lb/>maneggiar facilmente i canocchiali, di lunga distanza focale; mac&shy;<lb/>china che si distinse col nome proprio di <emph type="italics"/>Arcicanna.<emph.end type="italics"/> Carlo Roberto <lb/>Dati pure vi fu chiamato e ivi lesse un Discorso astronomico sul <lb/>sistema Saturnio in favor dell'Huyghens. </s>

<s>Un'altra strana e torbida <lb/>figura di uomo venuto di Reggio di Calabria, col nome di Antonio <lb/>Oliva, si vede pure trasparir di mezzo a questi gentiluomini eruditi <lb/>fiorentini. </s>

<s>Il Borelli, nel riferir di lui un'esperienza fatta, per de&shy;<lb/>terminare il peso specifico dell'aria, lo chiama <emph type="italics"/>ingeniossimus,<emph.end type="italics"/> e al&shy;<lb/>trove, uomo <emph type="italics"/>perspicacissimi et ignei ingenii<emph.end type="italics"/> (De mot. </s>

<s>nat. </s>

<s>pag. </s>

<s>470). <lb/>Se per&ograve; si debba giudicare dai frutti, queste lodi e altre pi&ugrave; ma&shy;<lb/>gnifiche, con le quali si messe a esaltarlo il Redi, si riconoscono <lb/>per non meritate. </s></p><p type="main">

<s>A valer per tutti insieme i cinque sopra commemorati, il <lb/>principe Leopoldo aveva rivolte le sue mire anche su Gian Do&shy;<lb/>menico Cassini, il quale intanto pensava ad alcune esperienze da <lb/>farsi nell'Accademia sopra la calamita. (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XXI, c. </s>

<s>64). <lb/>Ma poco dopo avvenne caso, che la Corte medicea dovesse adom&shy;<lb/>brare di esso, e fu quando, trovandosi col Viviani a trattar del <lb/>negozio delle Chiane, faceva del s&igrave; no, di che il Viviani stesso dole&shy;<lb/>vasi col principe Leopoldo, qualificando l'ingegnere di Papa Ales&shy;<lb/>sandro VII per uomo doppio. (Ivi, T. XVII, c. </s>

<s>236). Millantatore, a <lb/>proposito delle sue scoperte celesti, nelle quali troppo esagerata&shy;<lb/>mente vantava l'eccellenza dei canocchiali di Giuseppe Campani, <lb/>parve al Borelli (ivi, T. XVIII, c. </s>

<s>90), e una certa sua ruvidezza <lb/>nizzarda lo faceva accusar di malcreato alla cortigiana galanteria del <lb/>Magalotti. (Targioni, Aggrandim. </s>

<s>T. I. P. I. pag. </s>

<s>249). Per tutte queste <lb/>ragioni, il Principe dell'Accademia fiorentina par che se lo tenesse <lb/>un po'alla lontana, bench&egrave; dispensasse anco a lui favori, e si cu&shy;<lb/>rasse di far verificare in Astronomia tutte le grandi scoperte, che <lb/>di Roma veniva annunziando e di Parigi. </s>

<s>Duole nulladimeno a pen&shy;<lb/>sare che molte di quelle insigni scoperte cassiniane, come l'ombre <lb/>dei satelliti proiettate sul disco di Giove, e le quattro nuove lune <pb xlink:href="020/01/214.jpg" pagenum="195"/>saturnie, fossero messe in dubbio dai Nostri, e con poca dignit&agrave; di <lb/>conte e con minore acume di scienziato, lo deridesse il Magalotti <lb/>e gli negasse fede, perch&egrave; non gli pareva possibile che avesse ve&shy;<lb/>duto lui tanti mondi lontani, che non valeva a leggere un carattere <lb/>chiaro e ben formato, senza gli occhiali. (Targioni, ivi, pag. </s>

<s>395). </s></p><p type="main">

<s>Il Borelli e il Viviani avevano nulladimeno supplito nell'Acca&shy;<lb/>demia alla mancanza del Cassini, ma le belle invenzioni e le belle <lb/>scoperte fatte da ingegni tanto eccellenti rimanevano tuttavia rin&shy;<lb/>chiuse fra le dorate pareti del Palazzo Pitti. </s>

<s>Intanto, incominciava <lb/>a destarsi nell'animo dei Nostri qualche sentimento di gelosia e di <lb/>rivalit&agrave; coll'Accademia sperimentale instituita in Francia, e ci&ograve; ri&shy;<lb/>dest&ograve; qualche proposito di far noto ai nuovi Filosofi parigini quel <lb/>che prima di loro era stato sperimentato gi&agrave; in Firenze. </s>

<s>Intorno a <lb/>che, da Pisa il di primo Dicembre 1658 scriveva cos&igrave; il Borelli al <lb/>principe Leopoldo: &ldquo; Il sig. </s>

<s>M. A. </s>

<s>Ricci mi replica questa settimana <lb/>e con molte ragioni vive ed efficaci procura mostrare quanto pre&shy;<lb/>giudizio si faccia alla nostra Accademia ed all'Italia tutta con il <lb/>nostro tacere, e non scrivere a quei signori di Francia. </s>

<s>Vorrebbe <lb/>egli insomma che si palesassero le conclusioni da noi ritrovate e <lb/>dimostrate, tacendo per&ograve; ed occultando le ragioni e le dimostra&shy;<lb/>zioni. </s>

<s>In questa maniera, dice egli, potremo esser sicuri che non <lb/>ci possa esser tolto il primo luogo dell'invenzione preoccupata e <lb/>palesata da noi &rdquo; (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XVI, c. </s>

<s>130). </s></p><p type="main">

<s>Nel di primo di Febbraio del 1663, Carlo Dati avvisa il Principe <lb/>dell'Accademia che eran gi&agrave; pronte &ldquo; quattro casse di carta bonis&shy;<lb/>sima per la stampa del Libro delle Esperienze &rdquo; (ivi, T. XVII, c. </s>

<s>184) <lb/>la quale stampa, qualunque ne fosse la ragione, non ebbe effetto <lb/>che nel 1666. Il titolo di <emph type="italics"/>Saggi di Naturali esperienze<emph.end type="italics"/> dato al libro, <lb/>corrisponde benissimo alla realt&agrave; dei fatti, non essendovisi dato, dei <lb/>varii ordini di esperienze naturali, che la descrizione di qualcune <lb/>fra le molte, come per saggio. </s>

<s>Solo &egrave; da notare che nulla vi fu <lb/>saggiato di cose astronomiche, e ce ne avevan pure i nostri Acca&shy;<lb/>demici delle importanti. </s>

<s>L'intenzione del Principe era veramente <lb/>di non lasciarle addietro, e il Magalotti aveva gi&agrave;, fra le descrizioni <lb/>degli altri strumenti, distesa anche quella dei canocchiali e delle <lb/>macchine da maneggiarli servite nelle ossvrvazioni di Saturno (ivi, <lb/>T. VII, c. </s>

<s>23) con manifesto proposito di dar, anche di queste os&shy;<lb/>servazioni, un qualche saggio, fra gli altri del libro. </s>

<s>Ma la causa, <lb/>per cui un tal proposito del Principe e del Segretario non si man&shy;<lb/>dasse ad effetto, si viene a conoscere da una Lettera del Borelli, <pb xlink:href="020/01/215.jpg" pagenum="196"/>in cui scriveva da Pisa il di 20 Aprile 1665, le parole seguenti: <lb/>&ldquo; &Egrave; venuta la scrittura inviata dal sig. </s>

<s>Magalotti, nella quale veggo <lb/>registrato parte di quelle cose che io speculai e diedi in iscritto al&shy;<lb/>l'A. V. S. cinque anni sono intorno al sistema di Saturno del signor <lb/>Hugenio. </s>

<s>E bench&egrave; il pensiero del sig. </s>

<s>Magalotti sia di toglier <lb/>l'occasione, con la stampa, che altri non si vada usurpando le cose <lb/>da noi ritrovate, tuttavia, avendoci io in questo negozio il maggior <lb/>interesse, perch&egrave; io proposi, predissi e dimostrai l'effetto della <lb/>macchinetta, e poi recai molte scritture, in tutte le quali i signori <lb/>Accademici non ci ebbero altra parte che l'onore che mi fecero <lb/>di vederle ed approvarle per lor gentilezza; mi par di trovarmi in <lb/>obbligo di supplicar umilmente V. A. che si compiaccia di darmi <lb/>tempo per far la scelta, ed impinguare e stabilir bene le cose per <lb/>esser di maggiore importanza lo stampare che scrivere una lettera <lb/>privata &rdquo; (ivi, T. XVIII, c. </s>

<s>164). Il Borelli per&ograve; non prese mai il <lb/>tempo, e quelle astronomiche Scritture rimasero allora e rimangono <lb/>tuttavia in gran parte manoscritte. </s>

<s>Manoscritto pure, nonostante la <lb/>benemerita opera fattavi attorno dal Targioni, dal Gazzeri, e da <lb/>qualcun altro, rimase gran parte di quel ricco tesoro di esperienze, <lb/>da cui si tolsero i <emph type="italics"/>Saggi.<emph.end type="italics"/></s></p><p type="main">

<s>Bench&egrave; poi s'aggiunga al titolo di Naturali Esperienze, che <lb/>furon fatte <emph type="italics"/>nell'Accademia del Cimento sotto l&agrave; protezione del prin&shy;<lb/>cipe Leopoldo di Toscana,<emph.end type="italics"/> nonostante vi si accolgono anche descri&shy;<lb/>zioni di esperienze e di strumenti, che appartengono al primo e al <lb/>secondo periodo dell'Accademia Medicea. </s>

<s>Cos&igrave;, l'esperienza dell'in&shy;<lb/>compressibilit&agrave; dell'acqua dimostrata per mezzo della sfera ammac&shy;<lb/>cata, il Borelli ci dice essere stata fatta <emph type="italics"/>in Aula Serenissimi M. D. He&shy;<lb/>truriae. </s>

<s>Is iussit (ut mihi relatum fuit) cavam pilam argenteam <lb/>aqua repleri, ecc.<emph.end type="italics"/> (De moti. </s>

<s>natur. </s>

<s>ed. </s>

<s>cit. </s>

<s>pag. </s>

<s>333). Il Termo&shy;<lb/>metro a liquido e l'Igrometro a condensazione appartengono, come <lb/>si vide, al primo periodo, e al secondo appartengono l'esperienze <lb/>per la misura della velocit&agrave; della luce e dei suoni. </s></p><p type="main">

<s>Da ci&ograve; si conclude che il Libro, pubblicato nel 1666, contiene <lb/>i <emph type="italics"/>Saggi<emph.end type="italics"/> di tutta la sperimentale Accademia Medicea, che ebbe nel <lb/>Torricelli, infino dal 1642, i suoi primi principii. </s>

<s>Essendo cos&igrave;, pu&ograve; <lb/>a ragione vantar l'Italia il primato nella Scienza sperimentale sopra <lb/>tutte le altre Nazioni, avendo ella gi&agrave; maturati da qualche tempo i <lb/>suoi frutti, quando gl'ingegni del Pascal e del Roberval, dell'Auzout, <lb/>del Pacquet, del Boyle e di simili altri celebri stranieri non erano <lb/>ancora appena aperti nel fiore. </s></p><pb xlink:href="020/01/216.jpg" pagenum="197"/><p type="main">

<s>Il disteso di quel Libro, che &egrave; pure il pi&ugrave; insigne monumento <lb/>che sia stato eretto alla Scienza sperimentale italiana, fu fatto da <lb/>Lorenzo Magalotti succeduto ad Alessandro Segni nell'ufficio di Se&shy;<lb/>gretario dell'Accademia. </s>

<s>I meriti del Magalotti, come scienziato, non <lb/>sono per verit&agrave; di gran rilievo. </s>

<s>Pi&ugrave; inclinato forse allo speculare che <lb/>allo sperimentare, non sappiam di lui se non ch'ei lesse, ne'con&shy;<lb/>sessi accademici, un Discorso, in cui si proponeva di rassomigliar <lb/>l'anello di Saturno agli aloni e alle corone. </s>

<s>Come letterato per&ograve; <lb/>&egrave; tenuto in pregio da tutti, e s'ammira l'eleganza, la propriet&agrave; <lb/>del dire, e l'efficace evidenza delle sue descrizioni. </s></p><p type="main">

<s>I distesi del Magalotti, via via che erano all'ordine per la stampa, <lb/>si mandavano a rivedere al Borelli, che vi faceva sopra assai av&shy;<lb/>vertimenti, di molti de'quali si tenne conto; al Viviani, pi&ugrave; arren&shy;<lb/>devole in lasciar andar le cose a modo altrui, al Rinaldini, che, <lb/>seguitando a fare il capo sodo, aggiungeva a i cimenti dei fatti <lb/>naturali, il cimento della pazienza del Principe e del Segretario. </s>

<s><lb/>Poi si mandava tutto a Roma, e si sottostava, come a tribunale <lb/>inappellabile, a ci&ograve; che ne decidesse il giudizio di M. A. Ricci, <lb/>eletto, infin da principio, da Leopoldo dei Medici a consultore della <lb/>sua sperimentale Accademia. </s></p><p type="main">

<s>Il Ricci era geometra di gran valore e uomo di gran senno e <lb/>prudenza. </s>

<s>A lui il Torricelli indirizzava quelle lettere, che valgono <lb/>per un intiero Trattato, in cui si descrive la celebre esperienza <lb/>dell'argento vivo, e si risponde alle difficolt&agrave; promosse contro alla <lb/>natura del vacuo, e agli effetti della pressione ammosferica. </s>

<s>A ri&shy;<lb/>chiesta di lui chiamato <emph type="italics"/>ingeniosissimus iuvenis,<emph.end type="italics"/> il Torricelli stesso <lb/>risolse il problema della Clessidra, o del vaso che versa uguali quan&shy;<lb/>tit&agrave; d'acqua in tempi uguali, dimostrando che la forma propria di <lb/>un tal vaso, &egrave; il conoide generato dalla rotazione di una semipa&shy;<lb/>rabola biquadratica; problema che il Mariotte, il Grandi e lo stesso <lb/>Viviani credettero che l'Autor del Trattato <emph type="italics"/>De motu aquarum<emph.end type="italics"/> si <lb/>contentasse di proporlo agl'Idrometri, ma che poi l'avesse, per la <lb/>difficolt&agrave;, lasciato irresoluto. </s></p><p type="main">

<s><emph type="center"/>IX.<emph.end type="center"/></s></p><p type="main">

<s>La pubblicazione del Libro dei Saggi di Naturali Esperienze, <lb/>parve quasi un raccoglier le vele, e un ridursi in porto a riposo, <lb/>dopo una lunga navigazione. </s>

<s>Eppure il viaggio dura ancora e non <pb xlink:href="020/01/217.jpg" pagenum="198"/>breve, bench&egrave; avesse cambiato abito il piloto, fossero ai primi sot&shy;<lb/>tentrati altri nuovi e men validi remigatori, a nuova foggia si fosse <lb/>ricomposta la nave, e si dirigesse ad altro segno di stella. </s></p><p type="main">

<s>Il di 4 di Aprile 1667 il Borelli scriveva da Pisa una lettera <lb/>al principe Leopoldo, in cui gli diceva che andava <emph type="italics"/>disponendo le <lb/>cose per la partenza che non potr&agrave; esser prima di mezzo maggio,<emph.end type="italics"/><lb/>e intanto gli offeriva in dono e gli lasciava come ricordo di un <lb/>amico, che si allontana dall'amico, le <emph type="italics"/>macchine astronomiche<emph.end type="italics"/> da s&egrave; <lb/>erette e costruite nella specula di S. Miniato. (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XIX, <lb/>c. </s>

<s>180). Il Borelli abbandonava cos&igrave; l'ospitale Toscana per tornar&shy;<lb/>sene &igrave;n Sicilia. </s>

<s>Il d&igrave; 10 Febbraio 1668 Leopoldo de'Medici, nella <lb/>persona del quale s'era gi&agrave; al civile sopraggiunto il principato eccle&shy;<lb/>siastico, annunziava con accorata mestizia all'Huyghens che s'erano <lb/>partiti dal suo servizio tre dei migliori soggetti, che fossero nel&shy;<lb/>l'Accademia (Targioni, Aggrandim. </s>

<s>T. I, pag. </s>

<s>462) ed eran questi, <lb/>oltre al Borelli, il Rinaldini, e l'Oliva. </s>

<s>Tutto in sollecitudine per&shy;<lb/>ch&egrave;, da cos&igrave; fatta dispersione, non ne dovesse alla sua prediletta <lb/>Accademia conseguitare la morte, si rallegrava il Principe e Car&shy;<lb/>dinale col Magalotti, per avere intanto, a sostituire a uno dei tre <lb/>mancati, chiamato Niccol&ograve; Stenone, danese di patria, ma divenuto <lb/>italiano per elezione. </s>

<s>Il Magalotti rispondeva cos&igrave; alla lieta novella: <lb/>&ldquo; Veramente nella dispersione presente della nostra Accademia, per <lb/>la partenza del Borelli, dell'Oliva e del Rinaldini, non poteva a mio <lb/>credere, succedere cosa pi&ugrave; desiderabile, e se gli altri due luoghi si <lb/>riempissero a questa proporzione, mi parrebbe che avessimo qual&shy;<lb/>che motivo da consolarci della perdita fatta, la quale tutta insieme <lb/>bisogna confessare che &egrave; considerabile, perch&egrave; solamente dando al <lb/>Rinaldini e all'Oliva quel che v&agrave; loro per giustizia di approvazione <lb/>e di stima, il Borelli era un uomo fastidioso, e presso che io non <lb/>dissi affatto intollerabile, ma in sostanza era un letterato da far ri&shy;<lb/>splendere una corte, perch&egrave; aveva sodezza e giudizio. (Ivi, pag. </s>

<s>463). </s></p><p type="main">

<s>Un altro di que'posti lasciato vuoto nell'Accademia, fu sosti&shy;<lb/>tuito e, forse meglio che dallo Stenone, da Francesco Redi, il quale, <lb/>sebben fosse nel periodo precedente fra gli Accademici come ini&shy;<lb/>ziato, e avesse parte nelle esperienze sulla digestione degli animali, <lb/>su cui poi ritorn&ograve; nella Lettera al Kircher (Opera, T. II. </s>

<s>Napoli 1731, <lb/>pag. </s>

<s>49, 50), si vede nonostante esercitare con larga autorit&agrave; il suo <lb/>ministero in questo, che &egrave; il quarto periodo della sperimentale Ac&shy;<lb/>cademia Medicea, e, che va a terminare colla morte del Cardinale <lb/>Leopoldo. </s></p><pb xlink:href="020/01/218.jpg" pagenum="199"/><p type="main">

<s>Il Viviani distratto, per le continue richieste del Principe e dei <lb/>privati, a sopraintendere ai tanti e spinosi negozii d'ingegneria <lb/>idraulica, il Magalotti che aveva oramai preso diletto de'lontani <lb/>viaggi, lasciavano a collaborar nell'Accademia lo Stenone e il Redi, <lb/>i quali proseguendo l'indirizzo dei loro studii, le fecero in parte <lb/>cangiare istituto, trapassando, dalle scienze fisiche, a coltivar con <lb/>pi&ugrave; genio la Storia naturale. </s></p><p type="main">

<s>Lo Stenone fu anatomico espertissimo, e fece fare notabili pro&shy;<lb/>gressi alla Miologia. </s>

<s>La Dissertazione <emph type="italics"/>De solido intra solidum na&shy;<lb/>turaliter contento,<emph.end type="italics"/> nella stampa della quale tanta amorosa cura si <lb/>prese il Viviani, &egrave; forse dalla fama esaltata sopra i meriti proprii, <lb/>bench&egrave; non si possa negar che non sia un precorrere alla scienza <lb/>dei nostri giorni l'insegnar, che ivi si fa dall'Autore, a riconoscer <lb/>l'et&agrave; della formazione di uno strato terrestre, congetturandola dalla <lb/>natura delle sostanze fossili trascinate e deposte dalle acque. (Flo&shy;<lb/>rentiae 1669, pag. </s>

<s>28). N&egrave; si pu&ograve; passar senza lode d'ingegno l'at&shy;<lb/>tribuir gli effetti del trasformarsi l'arida in mare e il mare in arida, <lb/>al non coincidere il centro di gravit&agrave; della terra col centro di figura. <lb/>(Ivi, pag. </s>

<s>172). Nel Tomo XXXII del Cimento son raccolti i mano&shy;<lb/>scritti dello Stenone in folio, di carattere minutissimo, informi, di&shy;<lb/>sordinati. </s>

<s>A ricercarvi, in tanta variet&agrave;, quel che &egrave; pi&ugrave; confacente al <lb/>proposito nostro, nel breve esame che ne abbiam fatto, si nota par&shy;<lb/>ticolarmente l'anatomia dei muscoli locomotori dell'occhio, e alcune <lb/>osservazioni intorno alla funzione fisiologica dell'organo della vista. </s></p><p type="main">

<s>Il Redi era tutt'altro ingegno, e se non sodo come quel dello <lb/>Stenone, pi&ugrave; elegante e pi&ugrave; vario. </s>

<s>Il Cardinale Leopoldo annunziava <lb/>con gran compiacenza al Borelli un nuovo libro scritto dallo stesso <lb/>Redi sopra gl'insetti, e il Borelli rispondeva di Messina, nell'Agosto <lb/>1668, che vedr&agrave; quel nuovo libro assai volentieri. (MSS. Gal. </s>

<s>Cim. </s>

<s><lb/>T. XIX, c. </s>

<s>202). N&egrave; il Serenissimo Cardinale di tale annunzio si <lb/>compiaceva senza ragione, perch&egrave; sentiva l'efficacia che avrebbero <lb/>avuto quelle pagine, in isgombrar largamente i sentieri ai progressi <lb/>della Zoologia, e anzi di tutta la Storia Naturale. </s>

<s>Il nuovo Autore <lb/>infatti dell'Esperienze intorno alla generazione degl'insetti, dimo&shy;<lb/>strava con sensati argomenti, ci&ograve; che non era riuscito al grandissimo <lb/>Harvey, esser la generazione spontanea un gravissimo e dannosis&shy;<lb/>simo errore, e che anco gli animali de'pi&ugrave; infimi ordini non hanno <lb/>origine dalla putredine, ma vi son deposti allo stato di uovo dalle <lb/>sollecite madri pregnanti. </s></p><p type="main">

<s>In un grave ostacolo per&ograve; offese il libero piede del nostro Redi, <pb xlink:href="020/01/219.jpg" pagenum="200"/>e fu quando s'incontr&ograve; a decider dell'origine dei vermi, nella carne <lb/>de'frutti maturi, e dentro alle galle cresciute sui rami o sulle foglie <lb/>di alcuni alberi. </s>

<s>Parve a lui non &ldquo; esser gran peccato in Filosofia <lb/>il credere che i vermi de'frutti sieno generati da quella stessa <lb/>anima, e da quella stessa natural virtude, che fa nascere i frutti <lb/>stessi nelle piante &rdquo; (Opera, ivi. </s>

<s>T. I, pag. </s>

<s>103). Ma pure, bench&egrave; <lb/>cos&igrave; si andasse lusingando il celebre Autore, era quello di dar ani&shy;<lb/>ma e senso alle piante, tal peccato in Filosofia, da viziare il merito <lb/>delle altre sue insigni scoperte. </s></p><p type="main">

<s>Due anni dopo, lo stesso Eminentissimo Principe dell'Accade&shy;<lb/>mia fiorentina, dava, pure a proposito del Redi, un'altra nuova al <lb/>Borelli, ed era intorno all'esperienze fatte sulle gocciole bataviche <lb/>o sopra quelle perline di vetro, a rompere le codette alle quali, si <lb/>sgretolano tutte riducendosi in polvere. </s>

<s>Il Borelli, rispondendo da <lb/>Francavilla, ricorda come quindici anni prima il Card. </s>

<s>Giovan Carlo <lb/>avea mandato al Granduca una cassettina di quelle stesse perle, <lb/>sugli effetti curiosi delle quali speculando allora, si compiace che <lb/>si fosse riscontrato nei pensieri medesimi del Redi. (Fabbroni, Let&shy;<lb/>tere, T. I. pag. </s>

<s>139). </s></p><p type="main">

<s>Quel peccato filosofico, in che offese il Nostro, e di cui si par&shy;<lb/>lava dianzi a proposito della generazione di alcuni insetti, fu emen&shy;<lb/>dato da Marcello Malpighi, il quale dimostr&ograve; che anche i vermi <lb/>delle galle e dei frutti nascevano da un uovo deposto dalle madri. </s>

<s><lb/>Se gli onori si dispensassero sempre nel mondo a seconda dei me&shy;<lb/>riti, il Malpighi non dovrebb'esser, nei fasti della scienza, men <lb/>glorioso del celeberrimo Harvey. </s>

<s>Imperciocch&egrave;, se l'Inglese restaur&ograve; <lb/>la Fisiologia animale con la scoperta della circolazione del sangue, <lb/>il nostro Bolognese, con la scoperta del circolo della linfa, restaur&ograve; <lb/>la Fisiologia vegetabile. </s>

<s>L'anatomia microscopica degli organi e <lb/>della pi&ugrave; intima testura delle parti componenti le varie membra <lb/>delle piante e degli animali, &egrave; dovuta principalmente a lui. </s>

<s>Nella <lb/>mente di lui balen&ograve; il primo vero intorno alla teoria chimica della <lb/>respirazione, e fu egli il primo a dar la dimostrazione oculare del <lb/>moto del sangue nel circolo universale dei vasi. </s></p><p type="main">

<s>Al nome del Malpighi, non pu&ograve; andar disgiunto quello di Lo&shy;<lb/>renzo Bellini, con l'altro di Carlo Fracassati, i quali ambedue, con&shy;<lb/>corsero, ciascuno per la sua parte, a dar l'anatomia e la fisiologia <lb/>dell'organo del gusto. </s>

<s>Nessuno di questi tre insigni anatomici ap&shy;<lb/>partenne, &egrave; vero, all'Accademia Medicea; anzi il Malpighi, cosa <lb/>notabilissima in uomo di tanto merito, non solo fu tenuto lontano <pb xlink:href="020/01/220.jpg" pagenum="201"/>dal partecipar la sua scienza con Firenze, ma si direbbe che fu <lb/>tenuto lontano dall'Italia, dalla quale, n&ograve; nella persona ma nelle <lb/>opere dell'ingegno, par che esulasse in Inghilterra, dove, nella <lb/>R. </s>

<s>Societ&agrave; di Londra, le tante e mirabili scoperte di lui ebbero <lb/>liete accoglienze, e gli scritti, cos&igrave; vivente l'Autore che postumi, vi <lb/>trovarono le sollecite e amorevoli cure della pubblica stampa. </s>

<s>Non <lb/>appartengono propriamente, ripigliando qui il costrutto interrotto, <lb/>i tre grandi anatomici all'Accademia fiorentina, ma son tutt'e tre <lb/>discepoli del Borelli, e incominciarono i loro esercizi anatomici col <lb/>collaborare alla grande Opera dei Moti animali, che il loro Maestro <lb/>preparava gi&agrave; in Pisa e in Livorno, dove a spese e sotto la prote&shy;<lb/>zione dei principi Medicei si facevano le dissezioni. </s></p><p type="main">

<s>In ogni modo, quello stesso Borelli che, instituendo, in mezzo <lb/>alle scienze sperimentali, la nuova scuola iatromatematica, v'aveva <lb/>allevati il Malpighi, il Bellini e il Fracassati, i quali applicavan sa&shy;<lb/>pientemente le nuove scoperte d'Anatomia e di Fisiologia all'eser&shy;<lb/>cizio dell'arte medica; dalla lontana Sicilia tornava spesso col pen&shy;<lb/>siero in Toscana. </s>

<s>E ci&ograve; segu&igrave;, con pi&ugrave; vivo desiderio che mai, quando <lb/>il Cardinal Leopoldo gli annunziava di aver riscontrato nella sua <lb/>Accademia un'esperienza bellissima venuta d'Inghilterra. </s>

<s>&ldquo; Ralle&shy;<lb/>gromi sommamente, cos&igrave; incominciava lo stesso Borelli una sua <lb/>lettera del 2 Luglio 1669, scritta da Messina, dell'esperienza del <lb/>Boyle, che V. A. ha fatto confrontare la qual veramente &egrave; mirabile <lb/>e di gran conseguenza, ed ha risvegliato in me il desiderio di To&shy;<lb/>scana &rdquo; (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XIX, c. </s>

<s>263). E sotto il d&igrave; 14 Agosto <lb/>tornava a scrivere cos&igrave; sul medesimo argomento: &ldquo; Avevo io letto <lb/>nella Gazzetta letteraria di Roma l'esperienza del Boyle, e mi pa&shy;<lb/>reva veramente mirabile e per&ograve; desideravo sommamente di con&shy;<lb/>frontarla, sicch&egrave; pu&ograve; giudicare quanta consolazione io abbia avuto <lb/>sentendo che l'A. V. l'abbi sperimentata nella sua eruditissima Ac&shy;<lb/>cademia; e poi con tante belle circostanze di pi&ugrave; di quelle che <lb/>aveva osservate il Boyle &rdquo; (ivi, c. </s>

<s>267). </s></p><p type="main">

<s>La Lettera missiva del Serenissimo Cardinale, in data del 25 <lb/>Luglio 1669, e alla quale si riferisce la sopra citata responsiva del <lb/>Borelli, diceva cos&igrave; a proposito dell'esperienza del Boyle, riscon&shy;<lb/>trata, variata e ampliata nell'Accedemia del Cimento: &ldquo; In oltre le <lb/>diedi conto di un'esperienza fatta in Inghilterra, e rifatta qui da <lb/>me, la qual &egrave; che, mettendosi un pezzetto di pesce o interiora di <lb/>quelle che son vicine a infradiciarsi, fanno lume da s&egrave; stesse, dato <lb/>il solito strumento del vacuo, e facendosi la consueta operazione <pb xlink:href="020/01/221.jpg" pagenum="202"/>di quello, che comunemente si dice il vacuo, il lume del pesce si <lb/>perde, e facendo appresso un piccolo foro per introdurvi l'aria, <lb/>all'ingresso di quella di nuovo ritorna a risplendere il pezzetto di <lb/>pesce. </s>

<s>Ed io ho gi&agrave; fatto l'esperienza con un pezzetto di polpa e <lb/>grasso di pesce spada. </s>

<s>Mi venne poi in mente di fare l'esperienza <lb/>stessa con le lucciole, le quali ancora nel vuoto persero il lume. <lb/></s>

<s>&Egrave; ben vero che nell'istante dell'introduzione dell'aria s'illumin&ograve; <lb/>per brevissimo tempo tutto il vaso, ed io dubitando che questo <lb/>splendore potessi procedere che nel ricever le lucciole la consola&shy;<lb/>zione del ritorno dell'aria facessero moto, nel quale scoprissero la <lb/>parte lummosa, rifeci l'esperienza, mettendo dentro nel vaso tutte <lb/>le lucciole morte, e nondimeno successe l'istessa istantanea illu&shy;<lb/>minazione del vaso, nell'atto dell'introdurvi l'aria per il solito pic&shy;<lb/>colo foro formato da uno spillo. </s>

<s>Or &egrave; da sapersi di pi&ugrave; che, dopo <lb/>questa illuminazione, il lume che hanno le lucciole &egrave; rimasto, <lb/>(sempre che si &egrave; fatta l'esperienza) meno vivace, ma con tale dif&shy;<lb/>ferenza che non si &egrave; potuto mettere in dubbio che non sia cos&igrave;. </s>

<s><lb/>Questa &egrave; un'esperienza facile e galante, ma tale che io credo che <lb/>meriti che vi si faccia riflessione &rdquo; (ivi, T. XXIII, c. </s>

<s>171, e Fabbroni, <lb/>Lett. </s>

<s>I, pag. </s>

<s>144). </s></p><p type="main">

<s>Nel principio di questa lettera, passata fra Leopoldo de'Medici <lb/>e Gian Alfonso Borelli, s'accennava altresi a un altro soggetto di <lb/>scienza alquanto diversa. </s>

<s>Il Cardinale scriveva di sentir <emph type="italics"/>desiderio <lb/>d'aver qualche particolare informazione delli accidenti del fuoco <lb/>di Catania,<emph.end type="italics"/> e il Borelli rispondeva d'aver gi&agrave; scritto prolissamente <lb/>intorno a quegli accidenti e d'avervi di pi&ugrave; accompagnata una <lb/>pianta e disegno grande della Montagna e citt&agrave; di Catania, disegno <lb/>e scrittura che andarono forse smarriti e a cui suppl&igrave; l'anno dopo <lb/>l'Autore pubblicando l'<emph type="italics"/>Historia et Meteorologia Incendii Actnaei.<emph.end type="italics"/><lb/>Nella Prefazione al libro si leggono le notabilissime parole seguenti: <lb/>&ldquo; At non potui petitionibus plurimorum insignium virorum non <lb/>obtemperare, et praecipue Serenissimi ac Reverendissimi Cardinalis <lb/>Medicei, qui, cum proximum Incendium Aetnae undique fama cir&shy;<lb/>cumferret, primis suis humanissimis literis iussit ut scientiam Na&shy;<lb/>turalem promovere pro viribus satagerem, edendo Historiam et <lb/>Meteorologiam huius conflagrationis, iuxta praescriptum Societatis <lb/>seu Academiae Experimentalis Medicaee, cuius inter socios me re&shy;<lb/>censere olim dignatus fuerat. </s>

<s>&rdquo; </s></p><p type="main">

<s>Di qui si raccoglie che il Borelli, bench&egrave; assente dalla Toscana, <lb/>seguitava ad appartenere e a collaborare ancora, sotto gli ordini <pb xlink:href="020/01/222.jpg" pagenum="203"/>del Principe, nell'Accademia del Cimento. </s>

<s>Vi collaborava altresi, <lb/>quando riferiva allo stesso Principe le sue osservazioni ed esperienze <lb/>chimiche fatte nella grotta del lago di Agnano, qualificando l'ani&shy;<lb/>dride carbonica per un <emph type="italics"/>fluore simile in sembianza all'aria ma assai <lb/>pi&ugrave; denso.... che smorza i lumi e soffoca le persone<emph.end type="italics"/> (ivi, T. XIX, <lb/>c. </s>

<s>35); vi collaborava, quando, speculando sull'origine delle reliquie <lb/>fossili trovate da'suoi Colleghi Accademici in Toscana, e da s&egrave; stesso <lb/>in Sicilia, poneva, insieme con lo Stenone, i fondamenti scientifici <lb/>alla moderna Paleontologia. </s></p><p type="main">

<s>Anche il Viviani, tornando a quando a quando in Firenze con <lb/>gli stivaloni inzaccherati dal diguazzar lungo l'argine e per i greti <lb/>de'fiumi, o intorno alle gore de'mulini, attendeva a collaborar <lb/>qualche poco nell'Accademia. </s>

<s>Ne'suoi Manoscritti si legge, fra le <lb/>altre, autografa questa nota: &ldquo; D'ordine del Serenissimo Principe <lb/>Cardinale Leopoldo de'Medici, nel giardino del Serenissimo Gran&shy;<lb/>duca, la sera delli 17 Luglio 1674 in Firenze, con occhiale di braccia <lb/>tre e mezzo, con due lenti, l'obiettiva cio&egrave; e l'oculare, e con oriolo <lb/>col pendolo aggiustato a mezzogiorno, a ore otto e un quarto po&shy;<lb/>meridiane, fu principiata da me l'osservazione dell'ecclisse lunare &rdquo; <lb/>(MSS. Gal. </s>

<s>Disc. </s>

<s>T. XXXIX, c. </s>

<s>46). </s></p><p type="main">

<s>In questo quarto periodo della Sperimentale Accadem&igrave;a toscana, <lb/>non si vede pi&ugrave; quella regolarit&agrave; di sessioni, e quegli ordini, con <lb/>che si regolava nel periodo precedente, ma ci&ograve;, come si notava negli <lb/>esempii ora citati del Borelli, da null'altro dipende che dall'esser <lb/>la maggior parte dei collaboratori dispersi, per cui, invece di trattar <lb/>de'soggetti sperimentali colla parola viva, al cospetto del Principe, <lb/>ne trattavano in iscritture, le quali avevano forma di Dissertazioni <lb/>o di lettere che via via s'indirizzavano a Firenze. </s>

<s>Due de'pi&ugrave; in&shy;<lb/>faticabili e valorosi, fra'cos&igrave; fatti collaboratori, furono Geminiano <lb/>Montanari e Donato Rossetti, diversi d'indole e d'ingegno, e perci&ograve; <lb/>contenziosi. </s>

<s>Le controversie fra questi due, o incominciarono o in&shy;<lb/>fierirono vie pi&ugrave;, a proposito delle esperienze sui capillari, intorno <lb/>a che il Borelli ebbe a risentirsi e a muover lagnanza per lettera <lb/>al Cardinal Leopoldo, contro lo stesso Montanari, tacciandolo di <lb/>discepolo ingrato e accusandolo di plagio, perch&egrave;, mentre costui <lb/>dimorava in Firenze, e conversava coi fratelli Del Buono, infor&shy;<lb/>mandolo di tuttoci&ograve; che si faceva ne'consessi dell'Accademia spe&shy;<lb/>rimentale, ebbe dagli stessi Del Buono la notizia dell'attrarsi, per <lb/>effetto di capillarit&agrave;, i galleggianti sull'acqua, e poi divulg&ograve; la cosa <lb/>come per sua. </s>

<s>Di ci&ograve; il Borelli infuriava e rivendicava a s&egrave; la sco-<pb xlink:href="020/01/223.jpg" pagenum="204"/>perta chiamando in testimonio lo stesso Granduca, e altri signori <lb/>della sua corte, alla presenza de'quali, infino dal 1655, aveva mo&shy;<lb/>strata la curiosit&agrave; di quella nuova esperienza. (MSS. Gal. </s>

<s>Cim. </s>

<s><lb/>T. XIX, c. </s>

<s>93). </s></p><p type="main">

<s>Comunque sia, il Montanari era ingegno pi&ugrave; maturo e pi&ugrave; as&shy;<lb/>sennato del Rossetti, e a giudicar dall'opere si direbbe che il primo <lb/>ritrae pi&ugrave; al vivo quella profondit&agrave; e quell'ampiezza di studi spe&shy;<lb/>rimentali, propria del Borelli, che egli, con lo stesso Rossetti, ebbe <lb/>a comune maestro. </s>

<s>Il micrometro e il canocchiale livellatore fanno <lb/>annoverare il Montanari fra gli inventori di strumenti pi&ugrave; utili e <lb/>pi&ugrave; necessarii ai progressi della scienza. </s>

<s>Le sue esperienze e i suoi <lb/>Discorsi intorno alle propriet&agrave; de'liquidi, e i suoi esami sopra la <lb/>direzione, le sue speculazioni sopra le cause e gli effetti delle cor&shy;<lb/>renti marine, lo sollevano al grado di primo e principale maestro <lb/>nella scienza del moto dell'acque. </s></p><p type="main">

<s>Per ci&ograve; che direttamente riguarda l'Accademia del Cimento <lb/>poi, riferisce al Principe e Cardinale l'esperienza della trasfusione <lb/>del sangue, pi&ugrave; particolarmente descritta in una Relazione, che <lb/>pass&ograve; per le mani del Cassini, prima di arrivare a Firenze; discute <lb/>la controversia ch'egli ha col Rossetti intorno alle dottrine di Ar&shy;<lb/>chimede e di Galileo sui galleggianti, e intorno agli effetti mec&shy;<lb/>canici della bilancia di braccia uguali; racconta la storia degli <lb/>effetti, e specula sulla natura delle folgori, dissipando vecchi pre&shy;<lb/>giudizi e presentendo le teorie elettriche dei moderni; riferisce <lb/>osservazioni di ecclissi di sole e di luna, di apparizioni di comete <lb/>e di molti altri fenomeni celesti. </s></p><p type="main">

<s>Il Rossetti, dall'altra parte, mandava all'Accademia fiorentina <lb/>una scrittura contenente XIX osservazioni fatte sulla brinata in <lb/>Torino nel mese di Gennaio 1675 (ivi, T. XX, c. </s>

<s>192-95), dava parte <lb/>di un nuovo pesce apparito nei nostri mari (ivi, c. </s>

<s>230) e riferiva <lb/>altre simili curiosit&agrave; scoperte in fatto di storia Naturale. </s>

<s>Rendendo <lb/>conto degli altri suoi studi, diceva di esser per metter mano alla <lb/>sua Architettura militare, trattata in Dialogo &ldquo; nella quale (son sue <lb/>parole) dove si discorrer&agrave; di fortificarsi vicino ai fiumi, piglier&ograve; <lb/>l'occasione di pubblicare il mio nuovo modo di frenare i fiumi, <lb/>acci&ograve; non si avanzino dove noi non vogliamo, e quivi, mentre non <lb/>abbia sentore che possa esser discaro cost&agrave; in Toscana, dimostrer&ograve; <lb/>le falsit&agrave; di alcuni principii del Michelini. </s>

<s>E dove si discorrer&agrave; di <lb/>fortificare accanto al mare, insegner&ograve; il modo di murare sott'acqua &rdquo; <lb/>(ivi, T. XX, c. </s>

<s>166). </s></p><pb xlink:href="020/01/224.jpg" pagenum="205"/><p type="main">

<s>Da tutte queste cose ora discorse &egrave; facile persuadersi che l'Ac&shy;<lb/>cademia del Cimento, in questo secondo periodo, s'allarg&ograve; ad ab&shy;<lb/>bracciare ogni sorta di scienza sperimentale, mentre nel periodo <lb/>precedente parve quasi ristringersi nel campo della Fisica. </s>

<s>Si di&shy;<lb/>rebbe che Leopoldo dei Medici volle onorar la Religione, nella <lb/>porpora cardinalizia, col coltivar pi&ugrave; largamente e col promuover <lb/>con pi&ugrave; ardore che mai la scienza, e non la sola scienza specula&shy;<lb/>tiva, ma le utili applicazioni altres&igrave; che si posson fare di lei al de&shy;<lb/>coro e alle comodit&agrave; della vita. </s>

<s>Basterebbe, oltre alle cose dette, <lb/>per conferma di ci&ograve;, commemorare, non direm l'accoglienza, ma gli <lb/>eccitamenti che dal Cardinale Leopoldo ebbero i due fratelli Cam&shy;<lb/>pani, quando, per utilit&agrave; della navigazione, proponevano una nuova <lb/>e, secondo loro, inalterabile costruzion di orologi. </s></p><p type="main">

<s>La sera del d&igrave; 10 di November dell'anno 1675, colla morte del <lb/>Cardinale Leopoldo de'Medici, le porte dell'Accademia del Cimento <lb/>furon chiuse per sempre. </s></p><p type="main">

<s><emph type="center"/>X.<emph.end type="center"/></s></p><p type="main">

<s>Le virt&ugrave; che risplendono dall'alto raro &egrave; che non accendan <lb/>gli animi di chi da pi&ugrave; basso luogo le guarda, a imitarne gli esempi. </s>

<s><lb/>Molti furono i signori privati in Italia che, ad imitazione di ci&ograve; che <lb/>facevasi in Firenze nella corte de'Medici, incominciarono a intrat&shy;<lb/>tener nei loro palazzi una scelta conversazione d'uomini dotti, a <lb/>speculare e a sperimentare di cose naturali. </s>

<s>Di queste private Ac&shy;<lb/>cademie si pu&ograve; commemorar fra le prime quella convocata nel 1674 <lb/>in Roma dal Cardinal Flavio Chigi, dove secondo il Porzio (Opera <lb/>omnia, T. II. Neap. </s>

<s>1736, pag. </s>

<s>280) si ripeterono tutte l'esperienze <lb/>fatte nel vuoto dall'Accademia fiorentina. </s>

<s>In secondo luogo poi non <lb/>si pu&ograve; tacer di quell'altra istituita in Bologna nella casa dell'abate <lb/>Sampieri, dove il Montanari fece quelle sue cos&igrave; importanti espe&shy;<lb/>rienze sulla viscosit&agrave; dei liquidi, e dove pure ei lesser que'suoi Di&shy;<lb/>scorsi sull'Idrostatica, da'quali poi largamente attinse il Guglielmini. </s></p><p type="main">

<s>Ma sopra queste due, come sopra parecchie altre, primeggia <lb/>l'Accademia napoletana convocata da don Andrea Conclubet, mar&shy;<lb/>chese d'Arena. </s>

<s>Il Borelli, nel dedicare a lui il suo libro <emph type="italics"/>De motio&shy;<lb/>nibus naturalibus.<emph.end type="italics"/> &ldquo; Tu ipse es, gli scriveva, qui in praeclara Urbe <pb xlink:href="020/01/225.jpg" pagenum="206"/>Partenopaea, mea parente, societatem seu Academiam in tuo Museo <lb/>erexisti, in qua certis et indubitatis experimentis, non vero inanibus <lb/>ac rixosis disputatiunculis, philosophicas veritates ad Reipublicae <lb/>litterariae bonum indagarentur, idque summa cura, ac munificentia <lb/>praestitisti, in unum collectis clarissimis doctissimisque viris, Cara&shy;<lb/>muele, Thoma Cornelio, Francisco De Andrea, Leonardo Capua, <lb/>Luca Antonio Portio, innumerisque aliis. </s>

<s>&rdquo; Fra questi soggiunge <lb/>tosto il Borelli d'essere stato annoverato anch'egli, ond'&egrave; che, per <lb/>non presentarsi in casa il Marchese a mani vuote, gli offerisce quel <lb/>suo nuovo Libro &ldquo; in quo rationes Philosophiae quam plurimum <lb/>experimentorum naturalium afferentur, quae Florentiae in Academia <lb/>experimentali Medicaea vidi, pariterque accuratissime sunt observata <lb/>in tua Neapolitana. </s>

<s>&rdquo; </s></p><p type="main">

<s>L'avere il Borelli dedicato all'Istitutore un Libro, che contiene <lb/>la Filosofia de'fatti semplicemente narrati o storicamente descritti <lb/>ne'<emph type="italics"/>Saggi,<emph.end type="italics"/> &egrave; grande onore e attestato de'meriti dell'Accademia napo&shy;<lb/>letana, assai pi&ugrave; valido di quel che non sia il citare i nomi dei primi <lb/>fra coloro che vi appartennero. </s>

<s>Leonardo da Capua ebbe princi&shy;<lb/>palmente fama da alcune <emph type="italics"/>Lezioni<emph.end type="italics"/> che, in affettata lingua del trecento <lb/>e in stil boccaccevole, pubblic&ograve; nel 1683 intorno alla natura delle <lb/>mofete. </s>

<s>Quel che egli ivi discorre delle esalazioni gazose del lago <lb/>di Agnano, della Grotta del Cane, e di simili, &egrave; una vera mofeta <lb/>di parole, e tutt'altro che apporsi al vero intorno all'essenza del&shy;<lb/>l'anidride carbonica, riman di molto inferiore al Borelli in quali&shy;<lb/>ficarne la chimica natura. </s>

<s>Quel che egli poi, nella II Lezione, vi <lb/>discorre del circolo sanguigno nell'animal che respira o nel feto, <lb/>non ha nulla che non sia stato prima insegnato dall'Harvey, dal <lb/>Boyle, nei Proginnasmi, dal Carnelio, e, nell'epistole sparse, dal <lb/>Malpighi. </s></p><p type="main">

<s>Luc'Antonio Porzio, che non sembra abbia da vantare altra <lb/>invenzione da quella in fuori delle fontane intermittenti applicate <lb/>a svelare il celebre mistero dei fonti plimani, e rivendicate da lui <lb/>sullo Chales, con tanto ardore; fu il pi&ugrave; zelante e ardito banditore <lb/>della filosofia cartesiana in Italia. </s>

<s>Nel Trattatello <emph type="italics"/>De motu corporum<emph.end type="italics"/><lb/>raffina la sofistica del Cartesio contro i principii meccanici comu&shy;<lb/>nemente approvati, e si compiace d'aver colto in fallo Galileo e i <lb/>seguaci di lui, i quali riguardaron le sfere gravi discendenti lungo <lb/>un piano inclinato, come non aventi alcuna sensibile proporzione <lb/>con la grandezza della sfera terrestre. </s>

<s>Cos&igrave; pure, ne'Discorsi IV e V, <lb/>in argomento d'acque correnti e della loro misura, applica la me-<pb xlink:href="020/01/226.jpg" pagenum="207"/>desima sofistica cartesiana a cogliere in fallo il Castelli, assottigliando <lb/>l'ingegno a dimostrare a quali false conseguenze condurrebbe in <lb/>qualche caso l'ammettere che le velocit&agrave; sieno in ragion reciproca <lb/>delle sezioni. </s>

<s>Lo stesso sofistico genio port&ograve; il Porzio in trattar <lb/>l'interminabile questione del vacuo; sofistico genio diciamo, perch&egrave; <lb/>il Cartesio inopportunamente introdusse la teoria antivacuista degli <lb/>spiriti eterei penetranti il vetro, insensibili, come gli stessi effluvii <lb/>magnetici. </s>

<s>Una tale inopportunit&agrave; poi si riconosce dal veder che <lb/>n&egrave; il Torricelli, n&egrave; nessun altro de'seguaci di lui, pretesero mai <lb/>altro, come sufficiente allo scopo loro, se non che lo spazio lascia&shy;<lb/>tosi dietro dall'argento vivo fosse vuoto di aria, non curandosi, del <lb/>resto, se in luogo di lei vi sottentrasse o vi rimanesse persistente, <lb/>e non avvertito da alcuno de'nostri sensi, quell'etere, che, col <lb/>Cartesio, il Porzio chiama <emph type="italics"/>primo elemento.<emph.end type="italics"/> Il principio della cir&shy;<lb/>cumpulsione invocato da Galileo contro la leggerezza positiva, e <lb/>confermato con varii e cos&igrave; concludenti esperienze nell'Accademia <lb/>fiorentina, vuole il Porzio che sia merce cartesiana. </s>

<s>&ldquo; Sempre, egli <lb/>dice, ne'moti dei corpi viene ad essere necessaria la circumpulsione, <lb/>che Tommaso Cornelio chiam&ograve; platonica, ed &egrave; la stessa che Renato <lb/>Des Cartes, prima di Tommaso Cornelio, riconobbe darsi in tutti <lb/>i moti de'corpi &rdquo; (Op. </s>

<s>cit. </s>

<s>pag. </s>

<s>200). </s></p><p type="main">

<s>Ma Tommaso Cornelio di Cosenza &egrave; pure il miglior soggetto <lb/>fra gli Accademici napoletani annoverati di sopra dal Borelli, bench&egrave; <lb/>il sentirlo, nel Proemio ai Proginnasmi, esaltare il Telesio e il Bruno, <lb/>il Campanella e lo Stelliola, il Digby e l'Hobbes al grado di gran <lb/>filosofi a pari del Gilberto e di Galileo, possa farlo odorar di poco <lb/>fino giudizio. </s>

<s>Nonostante l'avere avuto in Roma a Maestro, e di&shy;<lb/>rettor de'suoi studii Michelangiolo Ricci, confer&igrave; a infondergli quel <lb/>sano gusto nelle scienze sperimentali, di che dette poi splendidi <lb/>saggi il Cornelio, specialmente nella Fisiologia e nell'Anatomia. </s>

<s>A <lb/>lui, come altrove si disse, &egrave; dovuta, a dimostrar la direzion del <lb/>moto del sangue nelle arterie, l'esecuzione della esperienza gale&shy;<lb/>nica, che l'Harvey reputava impossibile; a lui l'anatomia delle <lb/>tuniche, che compaginano gli intestini; a lui la prima caccia contro <lb/>l'error del calore nativo, con attribuirne l'origine al moto del sangue. </s>

<s><lb/>Della circumpulsione platonica, di che facevasi cenno dal Porzio <lb/>nelle parole citate di sopra, ne tratta il Cornelio in una sua Lettera <lb/>pubblicata fin dal 1648, sotto il pseudonimo di Timeo Locrese, e <lb/>inserita poi in calce ai Proginnasmi. </s>

<s>In cotesta Lettera, che merit&ograve; <lb/>la traduzione italiana del Viviani, rimasta incompiuta fra'Mano-<pb xlink:href="020/01/227.jpg" pagenum="208"/>scritti di lui, si confermano le teorie torricelliane con argomenti <lb/>nuovi, e con nuove esperienze. </s>

<s>&Egrave; notabile questa scrittura del Fi&shy;<lb/>losofo e Medico Consentino, perch&egrave; la prima che, sopra cos&igrave; famoso <lb/>e importante soggetto, si vedesse in Italia, ci&ograve; che segu&igrave; in quel&shy;<lb/>l'anno stesso, in cui il N&ouml;el pubblicava le otto celebri esperienze <lb/>fatte gi&agrave; dal Pascal a Roano e a Parigi. </s></p><p type="main">

<s>La Filosofia cartesiana infaustamente fu introdotta dal Porzio <lb/>in Italia, e ci&ograve;, non perch&egrave; non fosse desiderabile tor di mezzo le <lb/>rivalit&agrave; e le inimicizie fra nostrali e stranieri, ma perch&egrave; quel cer&shy;<lb/>vello un po'leggiero del Fisico napoletano non parve vagheggiar <lb/>del Cartesio altro che i capogiroli e i sofismi. </s>

<s>Dall'altra parte <lb/>quelle rivalit&agrave; erano antiche, incominciate gi&agrave; fra il Cartesio stesso <lb/>e Galileo, due conquistatori venuti insieme a contesa del medesimo <lb/>principato. </s>

<s>Nell'Italiano per&ograve; era altera noncuranza, ma l'animo <lb/>del Bretone covava odio e recalcitrava con invidioso dispetto. </s>

<s>Dai <lb/>maestri quelle stesse rivalit&agrave; si tradussero poi ne'discepoli e se, <lb/>per non avere occasione a partecipare dei vizii, da una parte riu&shy;<lb/>scirono salutari, precludendo dall'altra gli aditi a partecipare delle <lb/>virt&ugrave;, tornarono, senza dubbio, nocive ai progressi scientifici delle <lb/>due Nazioni. </s></p><p type="main">

<s>Segnalato esempio di tali effetti nocivi lo abbiam noi Itallani <lb/>nella Diottrica diffusa nella <emph type="italics"/>Dissertazione del Metodo<emph.end type="italics"/> e, nonostante <lb/>alcune valide difficolt&agrave;, resa infin dal 1637 familiare in Francia. </s>

<s>Il <lb/>Mersenno consigliava nelle sue Lettere il Torricelli che leggesse <lb/>quella <emph type="italics"/>Dissertazione,<emph.end type="italics"/> ma questi se ne scusava, a principio, dicendo <lb/>che non intendeva la lingua francese. </s>

<s>Poi, quando fu fatta la tra&shy;<lb/>duzione latina, torna lo stesso Mersenno a sollecitar l'amico perch&egrave; si <lb/>risolva a comprare il libro, che trover&agrave; venale per tutto: non ostante <lb/>noi, dietro quel che abbiam potuto raccogliere dalla lettura del <lb/>carteggio manoscritto fra'due celebri uomini, non siamo in grado <lb/>di assicurare i nostri lettori della risoluzion del Torricelli. </s>

<s>Come <lb/>pur siamo incerti se questi entrasse veramente in quella corrispon&shy;<lb/>denza epistolare col Cartesio, dentro alla quale lo voleva ficcare il <lb/>Mersenno. (MSS. Gal. </s>

<s>Dis. </s>

<s>T. XLI, c. </s>

<s>42). </s></p><p type="main">

<s>Eppure il Torricelli lavorava allora attorno a cercar la miglior <lb/>figura da dare alle lenti dei canocchiali, e perch&egrave; si sentiva man<gap/><lb/>la scienza delle rifrazioni, non gl'importa nulla d'impararla alla <lb/>Diottrica del Cartesio, ma ne interroga in proposito il Cavalieri. </s>

<s>Il <lb/>Cavalieri poi rispondeva non saperne altro, da quello in fuori che <lb/>aveva trovato scritto nel <emph type="italics"/>Corso matematico<emph.end type="italics"/> dell'Herigonio; prote-<pb xlink:href="020/01/228.jpg" pagenum="209"/>stando per&ograve; di non credergli, per non gli parer possibile d'applicare <lb/>alla luce le leggi stesse del moto dei gravi. </s>

<s>Or perch&egrave; la Diottrica <lb/>del Cartesio era trattata allo stesso modo che dall'Herigonio, si <lb/>capisce d'onde mai movesse, anco indipendentemente dalle rivalit&agrave; <lb/>della scuola, la ritrosia del Torricelli e del Cavalieri, in accettar <lb/>la legge delle rifrazioni direttamente conclusa dai teoremi della <lb/>Meccanica. </s></p><p type="main">

<s>Tal ritrosia per&ograve; non fu sentita dal Viviani, in mano al quale, <lb/>capitata per caso, nel 1660, la Dissertazione del Metodo, ne rimase <lb/>maravigliato e rapito come a una nuova e inaspettata rivelazione. </s>

<s><lb/>Fu egli che primo introdusse nell'Accademia del Cimento e per <lb/>essa in Italia, derivandola dal Cartesio, la scienza della luce rifratta. </s>

<s><lb/>La ritrosia per&ograve; de'Colleghi f&ugrave; quella forse che gl'imped&igrave; di dif&shy;<lb/>fondere le nuove diottriche dottrine, ci&ograve; che f&ugrave; riserbato al Gri&shy;<lb/>maldi, il quale, riguardando la luce come un fluido qualunque, e <lb/>perci&ograve; anch'essa soggetta alle leggi di tutti gli altri fludi in moto, <lb/>s'apr&igrave; la via e riusc&igrave; alle sue insigni scoperte. </s></p><p type="main">

<s>Abbiamo accennato alla ritrosia de'colleghi del Viviani, fra'quali <lb/>il pi&ugrave; esagerato di tutti fu il Borelli, solito di chiamar le specula&shy;<lb/>zioni filosofiche del Cartesio col nome di <emph type="italics"/>arcolai.<emph.end type="italics"/> E non il Cartesio <lb/>solo aveva in dispetto il Borelli, ma adombrava, bench&egrave; senza mo&shy;<lb/>tivo, di tutti gli stranieri. </s>

<s>Quando, nel 1658, essendo a Roma, fa&shy;<lb/>ceva, per ordine del principe Leopoldo, ricerca de'manoscritti del <lb/>Magiotti e del Torricelli, e si trov&ograve; in mano la Lettera di questo <lb/>al Ricci sopra la celebre esperienza dell'argento vivo, ne dava parte <lb/>allo stesso Principe, cos&igrave; scrivendo: &ldquo; Alla mia venuta recher&ograve; la <lb/>copia di tutte queste lettere scientifiche del Torricelli, per farle <lb/>stampare, acciocch&egrave; non venga l'umore a qualche francese di pre&shy;<lb/>tendere anteriorit&agrave; (come gi&agrave; mi par che ve ne sia alcuno) sopra <lb/>questo gran concetto della compressione dell'aria cagione potissima <lb/>ed indubitabile del sollevamento dell'argento vivo nel cannello &rdquo; <lb/>(MSS. Gal. </s>

<s>Cim. </s>

<s>T. XVI. c. </s>

<s>103). Ora, questo del Borelli parr&agrave; un <lb/>temerario sospetto per chiunque ripensi che nessuno in Europa <lb/>ard&igrave; attribuirsi la grande scoperta torricelliana, da Valeriano Magno <lb/>in fuori, di cui un francese palesava pubblicamente il furto, resti&shy;<lb/>tuendo per giustizia la propriet&agrave; al Matematico del Granduca di <lb/>Toscana. </s>

<s>La data della Lettera del Roberval al Noyers, dove con <lb/>tanto zelo si fa una tale rivendicazione, ha la data di Parigi, otto&shy;<lb/>bre 1647, e fu ristampata in calce alla <emph type="italics"/>Demonstratio ocularis<emph.end type="italics"/> dello <lb/>stesso Magno, data in luce a Venezia due anni dopo la Lettera del <pb xlink:href="020/01/229.jpg" pagenum="210"/>Francese, e nove anni prima che nell'animo del Borelli entrasse <lb/>quel sospetto. </s></p><p type="main">

<s>E poich&egrave; non si poteva ragionevolmente sospettar da nessuno <lb/>de'francesi un attentato di furto, colla Lettera robervelliana sott'oc&shy;<lb/>chio, si direbbe che quasi i Nostri non fossero troppo bene infor&shy;<lb/>mati di quel che si scriveva in Francia delle cose loro. </s>

<s>Ci&ograve; che poi <lb/>si pu&ograve; ritenere per certo, &egrave; che i nostri Accademici non rivolsero <lb/>la debita attenzione al libro degli Esperimenti del Pecquet, ne'quali <lb/>tant'oltre si promuove dall'Autore la scienza torricelliana. </s>

<s>Prova <lb/>di questo sarebbe per noi il vedere in un Diario manoscritto essere <lb/>il Segretario incerto se sia del Roberval l'esperienza della vescica <lb/>nel vuoto, e nel Libro de'<emph type="italics"/>Saggi<emph.end type="italics"/> (Firenze 1841, pag. </s>

<s>27) s'attri&shy;<lb/>buisce al Roberval stesso l'esperienza del vuoto nel vuoto, mentre <lb/>il Pacquet chiaramente dice che fu prima felicemente tentata <emph type="italics"/>acu&shy;<lb/>tissimi Auzotii sagacitate.<emph.end type="italics"/> Bench&egrave;, a voler dir giusto, quel bellis&shy;<lb/>simo esperimento non fu primo a farlo n&egrave; il Roberval n&egrave; l'Auzout, <lb/>ma il Pascal, in pi&ugrave; elegante e facile modo. </s></p><p type="main">

<s>Che si vedesse poi da'Nostri questo ingerirsi degli stranieri <lb/>nella loro scienza di mal occhio, si prova per l'esempio del Boyle, <lb/>i Nuovi Esperimenti fisico meccanici del quale furono pubblicati <lb/>in inglese ne&igrave; 1659, e poco dopo a benefizio di tutti tradotti in la&shy;<lb/>tino. </s>

<s>Quei celebri esperimenti furono tutti fatti nel vuoto operato <lb/>per mezzo della macchina pneumatica, che perci&ograve; si disse <emph type="italics"/>vuoto <lb/>boileiano.<emph.end type="italics"/> Eppure i nostri Accademici tanto di mal animo s'indus&shy;<lb/>sero a far uso di quella macchina! Forse che essi credevano il <lb/>vuoto torricelliano dover riuscir pi&ugrave; perfetto? </s>

<s>Ma pure il Boyle <lb/>stesso ne'suoi Nuovi esperimenti <emph type="italics"/>circa relationem inter flammam <lb/>et acrem<emph.end type="italics"/> aveva discusso la questione, e aveva mostrato in quali <lb/>casi giovi sperimentar nel voto boileiano, e in quali nel torricel&shy;<lb/>liano; cosa dall'altra parte che i Nostri potevano saper benissimo <lb/>per loro propria esperienza. </s>

<s>Ma la ragion potissima perch'essi ri&shy;<lb/>fuggissero cos&igrave; dal vuoto boileiano, ce la dice chiara il Borelli, <lb/>quando, trovatasi dagli Accademici del Cimento gran difficolt&agrave; nel&shy;<lb/>l'agitare il bastoncino per confricar nel vuoto la pallottolina del&shy;<lb/>l'ambra, disperati pensarono di ricorrere alla Macchina boileiana. </s>

<s><lb/>Allora il Borelli immagin&ograve; un nuovo apparecchio, colla pratica del <lb/>quale sperava di agevolar l'esperienza <emph type="italics"/>senza chiedere aiuto a stra&shy;<lb/>nieri.<emph.end type="italics"/> (Targioni, Aggrandim. </s>

<s>T. II. P. II. pag. </s>

<s>606). Mossi pure da <lb/>questa intenzione il Borelli stesso e il Viviani gareggiarono insieme <lb/>a inventare il pi&ugrave; sicuro e pi&ugrave; comodo <emph type="italics"/>vaso del gran vacuo,<emph.end type="italics"/> dentro <pb xlink:href="020/01/230.jpg" pagenum="211"/>il quale per&ograve; non riuscirono a far l'esperienza del suono collo <lb/>strumento a fiato; e bench&egrave; l'unica, questa volta per&ograve; i nostri Ita&shy;<lb/>liani s'ebbero a umiliare e a chiedere aiuto allo straniero. </s></p><p type="main">

<s>Questo starsene a s&egrave; i Nostri e non voler partecipare con gli <lb/>stranieri, specialmente francesi, si potrebbe da qualche giudice se&shy;<lb/>vero sentenziare per un proceder d'animi appassionati, piuttosto <lb/>che d'uomini prudenti. </s>

<s>&Egrave; da osservar nonostante che non erano <lb/>cos&igrave; fatti sentimenti, nell'animo dei nostri Accademici, senza giusti <lb/>motivi, essendo consapevoli, e in parte testimoni, di ci&ograve; che il Mer&shy;<lb/>senno aveva fatto con Galileo e col Torricelli. </s>

<s>Il Magiotti poneva <lb/>in tumulto l'animo del buon Vecchio di Arcetri scrivendogli che <lb/>a quel frate era capitato in Francia il Libro <emph type="italics"/>De Motu,<emph.end type="italics"/> sopra il quale <lb/>egli, il frate stesso francese, <emph type="italics"/>voleva scompuzzare ogni cosa<emph.end type="italics"/> (Alb. </s>

<s>X, <lb/>205). Ma peggio che mai volle scompuzzare le cose al Torricelli, <lb/>quando, pi&ugrave; tardi venuto in Italia, e soggiornando in Roma, si <lb/>messe dietro al Magiotti e al Ricci, per saper le particolarit&agrave; delle <lb/>speculazioni torricelliane, specie intorno al moto dell'acque e dei <lb/>proietti; speculazioni che, tornato a Parigi, divulg&ograve; ne'suoi librac&shy;<lb/>cioni in gran fretta, prevenendo la pubblicazione delle <emph type="italics"/>Opere Geo&shy;<lb/>metriche<emph.end type="italics"/> dell'Autore, che lentamente in quel medesimo tempo si <lb/>stampavano in Firenze. </s></p><p type="main">

<s>Non credendo il Mersenno capace di commettere un atto di <lb/>tanta vilt&agrave;, quegli scienziati Romani conversavano volentieri con <lb/>lui, e bench&egrave; ridessero sotto sotto del sentirlo parlar familiarmente <lb/>un latino, <emph type="italics"/>che l'impatta talvolta con Merlin Coccaio, io per&ograve;,<emph.end type="italics"/> scrive <lb/>il Ricci al Torricelli, <emph type="italics"/>devo sempre dirne bene, se mi fa tutto quello <lb/>che mi ha promesso, cio&egrave; di procurarmi manoscritti e libri a noi <lb/>sconosciuti.<emph.end type="italics"/> (MSS. Gal. </s>

<s>Disc. </s>

<s>T. XLII, c. </s>

<s>71). Sembra che le promesse <lb/>non fossero mantenute, per cui, sciolto ogni ritegno, il Ricci qua&shy;<lb/>lifica il Mersenno per quel che egli era, colafizzandolo col titolo di <lb/><emph type="italics"/>Gesuito,<emph.end type="italics"/> bench&egrave; sentisse quanto quel di <emph type="italics"/>Minimo<emph.end type="italics"/> fosse, per altra <lb/>parte, tanto meglio appropriato. </s>

<s>E per ci&ograve; di lui stesso, accennando <lb/>in un'altra Lettera al Torricelli le difficolt&agrave; immaginate contro i <lb/>principii meccanici di Galileo, soggiunge: &ldquo; Con questo fondamento <lb/>presume il Gesuito d'alzar rocca inespugnabile a'danni di Galileo <lb/>e della sua scuola, e con mille vanti di s&egrave; medesimo e scherno del <lb/>Galileo, si dimostra non men leggiero ne'costumi che sia nelle dot&shy;<lb/>trine &rdquo; (ivi, c. </s>

<s>116). Cos&igrave; il Mersenno rimeritava l'ospitalit&agrave; degli <lb/>scienziati italiani colla sfacciataggine degli insulti, e con l'abbiet&shy;<lb/>tezza de'furti. </s></p><pb xlink:href="020/01/231.jpg" pagenum="212"/><p type="main">

<s>Quel Ricci nonostante era uomo di cos&igrave; perfetto giudizio da cono&shy;<lb/>scer quanto decoro sarebbe sopraggiunto all'Italia, e quanto se ne <lb/>sarebbe avvantaggiata la scienza dal partecipare insieme gli studi con <lb/>gli stranieri. </s>

<s>Volle perci&ograve; che la nostra del Cimento corrispondesse <lb/>coll'Accademia di Francia, e vi riusc&igrave; col mandare al Thevenot la <lb/>relazione dell'esperienza del fumo nel vuoto. </s>

<s>Il Thevenot stette <lb/>alquanto, ma poi rispose che era stata straordinariamente adunata <lb/>l'Accademia parigina, a fine di partecipare a que'signori <emph type="italics"/>l'esperienza <lb/>graziosissima venuta di Firenze.<emph.end type="italics"/> (Ivi, Cim. </s>

<s>T. XVII, c. </s>

<s>81). </s></p><p type="main">

<s>I consigli e le risoluzioni prese dal Ricci non potevano non <lb/>esser conformi alle intenzioni del principe Leopoldo, il quale era <lb/>intanto egli stesso entrato in relazione scientifica con uno de'pi&ugrave; <lb/>celebri e dotti uomini, che dimorassero allora in Parigi, Ismaele <lb/>Bullialdo. </s>

<s>Il Bullialdo poi introdusse in queste relazioni un altro <lb/>non men celebre e dotto uomo, che dall'Aja frequentava Parigi, <lb/>Cristiano Hugenio, e ci&ograve; fu a proposito della celebre controversia <lb/>sulla priorit&agrave; dell'applicazione del pendolo all'orologio. </s>

<s>Bench&egrave; dallo <lb/>zelo un po'troppo ardente, con che intendeva il Viv&igrave;ani d'esaltar <lb/>Galileo, l'altero Barone di Zulichemme sentisse qualche disgusto, <lb/>nonostante ei dovette dar pace e sentirsi anzi grato dell'accoglienze <lb/>che, fra i nostri Accademici, ebbero le sue dottrine e le sue sco&shy;<lb/>perte. </s>

<s>Il Viviani stesso, non sappiamo se per suo diporto o se per <lb/>servizio de'Principi, dava mano a tradurre l'Astroscopia, o la Nuova <lb/>arte di osservare le stelle (MSS. Gal. </s>

<s>Disc. </s>

<s>T. CXXXVIII, c. </s>

<s>124-47), <lb/>e per ordine espresso del Serenissimo Cardinale Leopoldo, faceva <lb/>un sunto, da leggersi nell'Accademia, di una Relazione intorno ad <lb/>alcune osservazioni fatte dall'Hugenio a Parigi, il d&igrave; 12 Maggio 1667, <lb/>di un alone o corona apparsa in quel giorno intorno al sole. (ivi, <lb/>T. CXXXIII, c. </s>

<s>135-44). Il Viviani altres&igrave; riferiva agli Accademici <lb/>suoi colleghi la nuova costruzione del canocchiale ugeniano, e i <lb/>primi tentativi e le speranze concepute dall'Olandese d'aver trovato <lb/>il modo di acromatizzare le lenti. </s>

<s>E il sistema Saturnio chi sa quante <lb/>contradizioni ancora avrebbe patito, se le ingegnose macchine im&shy;<lb/>maginate e descritte dal Borelli, non avessero fatto quasi scender <lb/>dal cielo il lontano pianeta, e rappresentarsi agli Accademici e agli <lb/>stessi pi&ugrave; volgari spettatori, sott'occhio. </s></p><p type="main">

<s>Non si pu&ograve; far motto del sistema Saturnio e dell'Accademia <lb/>fiorentina, senza fare a quel dell'Hugenio seguitar dietro il nome <lb/>di un altro straniero, a cui non sapremmo nemmen noi dar altro <lb/>nome che di <emph type="italics"/>cervellaccio.<emph.end type="italics"/> &ldquo; A quel cervellaccio, scriveva il Borelli <pb xlink:href="020/01/232.jpg" pagenum="213"/>di Onorato Fabry, gli son sovvenuti concetti assai simili a'miei, <lb/>con i quali spieg&ograve; le cagioni fisiche del moto de'pianeti &rdquo; (MSS. <lb/>Gal. </s>

<s>Cim. </s>

<s>T. XVIII, c. </s>

<s>110). Quel cervellaccio, per sostenere il gioco <lb/>di que'suoi globi bianchi e neri, danzanti intorno a Saturno, onde <lb/>cos&igrave; spiegare i fenomeni dell'anello, avrebbe seguitato ad agitare <lb/>interminabilmente la questione contro l'Hugenio, se il Ricci non <lb/>avesse consigliato e operato a troncarla. </s>

<s>Tanto era poi incaponito <lb/>di compor Saturno a suo modo, e tanto era persuaso non avercene <lb/>altro miglior di quello immaginato, che avendo ricevuto invito pi&ugrave; <lb/>volte da Giuseppe e da Matteo Campani di far esperienza della <lb/>verit&agrave; delle cose, guardando con uno de'pi&ugrave; eccellenti canocchiali <lb/>fabbricati da loro, non ci volle comparir mai. (MSS. Gal. </s>

<s>Disc. </s>

<s><lb/>T. CXLIV, c. </s>

<s>269). Dopo tanto combattere, fin&igrave; per rassegnarsi sotto <lb/>le bandiere del suo nemico, e nella fine del II de'suoi Dialoghi <lb/>fisici annovera, tra le nuove maraviglie scoperte nel cielo, l'anello <lb/>di Saturno <emph type="italics"/>a Christiano Hugenio viro clarissimo et omnigena lite&shy;<lb/>ratura probe instructo<emph.end type="italics"/> (Lugduni 1665, pag. </s>

<s>65). Cos&igrave; in pari modo, <lb/>dop'essersi fatto spacciare per primo autore dell'esperienza dell'ar&shy;<lb/>gento vivo, con facilit&agrave; e docilit&agrave; veramente filosofica, secondo <lb/>l'espression del Borelli, cant&ograve; la sua palinodia scrivendo nel IV <lb/>de'Dialoghi sopra citati: &ldquo; Primus illius inventor fuit doctissimus <lb/>Torricell&igrave;us, vir certe, quem inter principes huius temporis geo&shy;<lb/>metras iure innumero &rdquo; (ibi, pag. </s>

<s>182). </s></p><p type="main">

<s>Il Fabry, oltre ad essere straniero, era gesuita, che vuol dire <lb/>peripatetico o filosofante alla maniera di Aristotele intorno ai fatti <lb/>della Natura. </s>

<s>Assecondando perci&ograve; docilmente le cose al suo proprio <lb/>cervello, non risolve problema, non conclude questione ch'ei non <lb/>la coroni compiacente con dire: <emph type="italics"/>quid facilius, quid clarius?<emph.end type="italics"/> Ora <lb/>una tal Filosofia era tutta contraria a quella professata dai nostri <lb/>Accademici, i quali, trepitando in dover render la ragion fisica delle <lb/>cose, si contentarono quasi sempre, dopo lunghi e ripetuti esperi&shy;<lb/>menti, di descrivere i fatti come s'eran rappresentati ai loro sensi. </s>

<s><lb/>Non &egrave; maraviglia perci&ograve; se nessuno de'gesuiti fu chiamato mai a <lb/>partecipare de'Medicei sperimentali consessi. </s>

<s>E nonostante n'erano <lb/>in quel numero due, l'uno e l'altro italiani, che se fossero rimasti <lb/>nel loro filosofare liberi dal giogo peripatetico, avrebbero fatto ri&shy;<lb/>splendere, non una corte, come il Magalotti diceva del Borelli, ma <lb/>un'intera nazione. </s></p><p type="main">

<s>Giovan Batista Riccioli voleva tutto <emph type="italics"/>riformare,<emph.end type="italics"/> ossia ridur le <lb/>cose agli ordini antichi, o a que'nuovi da s&egrave; immaginati. </s>

<s>E perci&ograve;, <pb xlink:href="020/01/233.jpg" pagenum="214"/>tutt'altro che cimentare, metteva i fatti naturali a tortura, e voleva <lb/>che corrispondessero in ogni modo a'suoi preconcetti. </s>

<s>Nessuno che <lb/>si mette a svolgere i suoi ponderosi volumi non pu&ograve; non deplorare <lb/>che tanta infaticabile assiduit&agrave;, e tanta pazienza di sperimentare, <lb/>siano state rivolte piuttosto a compiacere una setta, che a benefizio <lb/>della scienza universale. </s></p><p type="main">

<s>Francesco Maria Grimaldi, concittadino e collega di lui negli <lb/>studii, presenta il caso pi&ugrave; strano, che si sia incontrato mai nella <lb/>storia letteraria. </s>

<s>Il celebre Trattato <emph type="italics"/>De Lumine<emph.end type="italics"/> lo divide in due <lb/>parti, nella seconda delle quali disdice tutto ci&ograve; che avea detto nella <lb/>prima. </s>

<s>Ma la stranezza maggiore consiste nel veder che l'Autore <lb/>s'adagia nel falso, dop'aver cos&igrave; strenuamente combattuto pel vero. </s>

<s><lb/>Qualunque sieno le ragioni pensate a spiegare un fatto tanto sin&shy;<lb/>golare, le due parti contradittorie del Trattato grimaldiano ebbero <lb/>una grande efficacia in promuover l'ottica, perch&egrave; par che la prima <lb/>di quelle parti abbia il precipuo scopo di dimostrare, che supposto <lb/>esser la luce soggetta alle passioni degli altri fluidi, si spiegano <lb/>facilmente gli antichi, e si scuoprono fenomeni nuovi; mentre sup&shy;<lb/>posto esser la luce una qualit&agrave;, conforme ai placiti peripatetici, come <lb/>si fa dall'Autore nella parte seconda, non s'incontrano che mani&shy;<lb/>feste contradizioni ed errori. </s></p><p type="main">

<s>Il Riccioli ebbe qualche raro commercio con alcuni de'nostri <lb/>Accademici privati: del Grimaldi non ne abbiamo trovato vestigio. </s>

<s><lb/>Si potrebbe sospettare che il principe Leopoldo non avesse cos&igrave; <lb/>fatta gente in buona grazia, e darebbe al sospetto qualche fon&shy;<lb/>damento una lettera, che il Rinaldini scriveva da Pisa al Viviani, <lb/>nel d&igrave; 9 Marzo 1658. &ldquo; Mi vien detto, scriveva, per cosa certissima <lb/>che i padri Gesuiti fanno strepito avanti il tempo, conciossiach&egrave; <lb/>dicono che, se nel Libro delle Osservazioni naturali fatte cost&igrave;, ci <lb/>sar&agrave; cosa che possi toccar qualcheduno di loro, che averanno uo&shy;<lb/>mini, a'quali d&agrave; l'animo di rispondere, e che frattanto, tutto che <lb/>possono sapere delle cose fatte procurano di sperimentare e di farne <lb/>un libro &rdquo; (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XXIV, c. </s>

<s>45) e seguita a rivelare in <lb/>gran segretezza alcune trame, e a dire un gran male de'gesuiti, <lb/>concludendo al Viviani, se lo credesse ben fatto, di confidare il tutto <lb/>al principe Leopoldo. </s></p><p type="main">

<s>Che quella setta peripatotica possa aver congiurato ai danni <lb/>dell'Accademia del Cimento, non fa maraviglia: per&ograve;, da questa <lb/>lettera del Rinaldini in fuori, non son noti a noi, per provare il <lb/>fatto, altri documenti, n&egrave; ci siamo curati di ricercarli. </s>

<s>Forse il prin-<pb xlink:href="020/01/234.jpg" pagenum="215"/>cipe Leopoldo, che sapeva non esser nella sua Accademia stato <lb/>offeso nessuno, se ne viveva tranquillo, e uomo di senno, piuttosto <lb/>che irritarsi, come da tanti si fa, avr&agrave; pensato ai benefizi grandis&shy;<lb/>simi, che conseguitano sempre dalle contradizioni, e come, se il <lb/>verno non li mortifica, poco giova a fecondare il seme de'campi <lb/>il tiepore di primavera. </s>

<s>Pi&ugrave; assai delle contrariet&agrave; de'peripatetici <lb/>dovevano mettere in sollecitudine il Principe le dissensioni fra'suoi <lb/>stessi Accademici, e specialmente quelle insorte fra il Borelli e il <lb/>Viviani. </s>

<s>Nate all'occasione della teoria dell'anello riscaldato e di&shy;<lb/>latato al calore, infierirono, le inimicizie fra'due grandi Geometri, <lb/>nella concorrenza che ebbero in tradurre i rimasti, e in divinare i <lb/>libri smarriti di Apollonio di Perga. </s>

<s>Chi conosce il carattere del <lb/>Borelli ammira la potenza che ebbe il principe Leopoldo in mante&shy;<lb/>nerlo collega e collaboratore, per dieci anni, all'odiato Viviani, e <lb/>in trattenerlo fino alla morte, o vicino o lontano, a suoi servigi; <lb/>potenza, nella quale, pi&ugrave; che l'altezza del grado, concorse l'affa&shy;<lb/>bilit&agrave; e la dolcezza dei modi. </s></p><p type="main">

<s>Pi&ugrave; tardi, quello stesso fastidioso Borelli, da cui tanti dispetti <lb/>ebbe a patire il docile Malpighi, entr&ograve; in fiera battaglia, direttamente <lb/>con Stefano Angeli, discepolo del Cavalieri e uno dei deputati a <lb/>rivedere il Trattato del Michelini, e indirettamente col Riccioli, a <lb/>proposito di un argomento sperimentale che questi adduce contro <lb/>il moto della Terra. </s>

<s>Era quella battaglia, piuttosto che condotta dal <lb/>valore, menata dalla rabbia, e perci&ograve; cos&igrave; accoratamente il principe <lb/>Leopoldo ne scriveva in proposito al Ricci: &ldquo; Mi dispiace, quando, <lb/>in queste occasioni di differenze letterarie, s'esce dai termini delle <lb/>dispute &rdquo; (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XXIII, c. </s>

<s>149). </s></p><p type="main">

<s>Ammirabile uomo da qualunque lato si guardi! sia qual si voglia <lb/>la cultura o la forza dell'ingegno di Leopoldo de'Medici, egli &egrave; pi&ugrave; <lb/>benemerito della scienza italiana di quegli stessi che sudarono sui <lb/>libri, o si affaticarono intorno agli esperimenti. </s>

<s>Cessata l'Accademia <lb/>colla morte di lui, le dottrine di Galileo parvero essere esaurite, per <lb/>essersi svolte in soverchiante abbondanza. </s>

<s>Or essendo legge natu&shy;<lb/>rale che in ogni tralcio trascorso, a voler mantenergli la virt&ugrave; di <lb/>fruttificare, conviene o di ritirarlo col ferro verso il suo principio, <lb/>o infondergli in qualche altro modo vigore novello; &egrave; perci&ograve; che <lb/>dopo l'Accademia del Cimento, incomincia per la Storia della nostra <lb/>Scienza un'altra et&agrave;, e cos&igrave; apresi innanzi ai nostri proprii occhi <lb/>una nuova scena, a rappresentare il terzo atto di questo Dramma. <pb xlink:href="020/01/235.jpg"/></s></p><pb xlink:href="020/01/236.jpg"/><p type="main">

<s><emph type="center"/>PARTE TERZA<emph.end type="center"/></s></p><p type="main">

<s><emph type="center"/>SOMMARIO.<emph.end type="center"/></s></p><p type="main">

<s>I. </s>

<s>Isacco Newton. </s>

<s>&mdash; II. De'principii e de'progressi delle speculazioni neutoniane, e quale efficace <lb/>concorso v'abbiano avuto le tradizioni scientifiche de'nostri italiani. </s>

<s>&mdash; III. </s>

<s>Delle Istituzioni <lb/>idrauliche di Domenico Guglielmini, e in che modo, i principii della Filosofia neutoniana, nel <lb/>secolo XVIII, concorressero a farle progredire. </s>

<s>&mdash; IV. Dell'elettricismo, della Chimica, dell'elettro <lb/>chimica, e come si svolgessero, queste nuove parti della scienza, dai principii della Filosofia <lb/>neutoniana. </s>

<s>&mdash; V. De'progressi della Storia Naturale, nel secolo XVIII. &mdash; Delle condizioni pre&shy;<lb/>senti delle scienze sperimentali: qualche parola intorno alla nostra Storia. </s></p><p type="main">

<s><emph type="center"/>I.<emph.end type="center"/></s></p><p type="main">

<s>Chi ripensa ai progressi straordinari fatti dalle scienze speri&shy;<lb/>mentali nel secolo XVIII, s'avvede assai facilmente che non pu&ograve;, <lb/>di tale effetto, esser unica tra le cause quella consueta d'operarsi <lb/>negli ordini trascorsi, e che &egrave; di ritirarli verso i loro principii. </s>

<s><lb/>Quell'effetto straordinario non poteva non esser prodotto da una <lb/>causa straordinaria, la quale consista in infondere in quegli stessi <lb/>ordini trascorsi, e ritirati gi&agrave; verso i loro principii, un vigor nuovo <lb/>di vita, come spesso avviene degli alberi fruttiferi della campagna. </s>

<s><lb/>In questo esempio si prova che sempre s'accresce o si perfeziona <lb/>la virt&ugrave; fruttificante de'rami, dall'infonder nel tronco la virt&ugrave; di <lb/>un altr'albero, che sia affine di genere, ma di specie alquanto di&shy;<lb/>versa. </s>

<s>Or la causa per cui, nel secolo XVIII, s'avvantaggiarono le <lb/>scienze sperimentali, in modo tanto straordinario, a noi sembra do&shy;<lb/>versi riconoscere in qualche cosa di simile a quel che si vede per <lb/>gli esempii degli alberi stessi; doversi cio&egrave; riconoscere in una specie <pb xlink:href="020/01/237.jpg" pagenum="218"/>d'innesto, il quale non &egrave; altro poi che un far concorrere insieme <lb/>due virt&ugrave; coniugate a produrre un unico effetto. </s></p><p type="main">

<s>L'innesto, di che si tratta, fu quello appunto che si fece in <lb/>quel tempo con tanto felice riuscita fra la Fisica e la Matematica. </s>

<s><lb/>Non si vuol gi&agrave; dir per questo che fosse, nel secolo precedente, <lb/>sconosciuto un tale efficacissimo connubio: aveva anzi Galileo mi&shy;<lb/>rabilmente promossa la scienza, insegnando a interpretar, per mezzo <lb/>delle Matematiche, i Misteri della Natura, e il Castell&igrave; aveva dimo&shy;<lb/>strato gi&agrave; come si dovesse trattar del moto delle acque, con rigo&shy;<lb/>roso ordine di Geometria. </s>

<s>Ci&ograve; per&ograve; non vuol dir altro, se non che, <lb/>da'due grandi Maestri della Scienza del moto de'gravi e delle Acque <lb/>correnti, s'eran felicemente coniugate insieme, nel secolo XVII, la <lb/>Fisica e la Geometria. </s>

<s>Non per&ograve; s'erano coniugate la Fisica con <lb/>la Matematica, per la quale non s'intende solo la Geometria, ma <lb/>la Geometria coniugata essa stessa coll'Algebra, ossia quell'<emph type="italics"/>Analisi,<emph.end type="italics"/><lb/>che la Scuola galileiana non conobbe, n&egrave; volle poi riconoscere, abor&shy;<lb/>rendo dal parteciparne come da contagiosa merce straniera. </s></p><p type="main">

<s>Vincenzio Viviani, in una di quelle sue prefazioni, o meglio, <lb/>in uno di quegli abbozzi di scritture, che dovevan poi ridursi a <lb/>servir di prefazione a quello e quell'altro libro del suo <emph type="italics"/>Sogno Idro&shy;<lb/>metrico,<emph.end type="italics"/> scritto in tempo che l'analisi, appresso gli stranieri e <lb/>specialmente i Francesi, era largamente e utilmente applicata; si <lb/>scusa del non essersene egli servito, nel trattar le sue quistioni <lb/>d'Idrometria, e dell'aver seguitato piuttosto l'antico metodo in&shy;<lb/>valso nella scuola galileiana, adducendo per sua ragione che se <lb/>l'Analisi, conferisce alla brevit&agrave;, recide per&ograve; i nervi, e rende anzi <lb/>impossibile, in trattar di soggetti fisici matematici, l'uso dell'elo&shy;<lb/>quenza. </s>

<s>Senza dubbio, una pagina irta di segni algebrici, tutt'altro <lb/>che incantar con quella dilettevole armonia, che risuona ne'Dialoghi <lb/>delle Due Nuove Scienze, farebbe gittar via il libro a chi ama veder <lb/>il vero uscir fragrante di mezzo ai fiori del bello, e in ci&ograve; il Viviani <lb/>aveva ragione. </s>

<s>Ma, come a tutti i vecchi avviene, era tenace troppo <lb/>degli usi antichi, e male secondava la gente nuova, anco per essere <lb/>straniera, la quale, al bello dell'eloquenza, preferiva la facilit&agrave;, con <lb/>la quale la nuova Analisi dimostrava la stessa cosa. </s>

<s>Ch&egrave;, dove le <lb/>proposizioni di Galileo e del Torricelli e degli altri simili, prima <lb/>di concludere, divagavano la mente per lungo e faticoso discorso, <lb/>i nuovi Analisti, con pochi simboli, conducevan diritti, e veloci, <lb/>come saette, a coglier nel segno. </s></p><p type="main">

<s>L'istituzione dell'Analisi matematica non si pu&ograve; negar che non <pb xlink:href="020/01/238.jpg" pagenum="219"/>fosse un gran benefizio, sebben l'unico, recato alle scienze speri&shy;<lb/>mentali dalla Filosofia cartesiana. </s>

<s>E dall'essersi quell'Analisi inco&shy;<lb/>minciata a coniugar con la Fisica, noi riconosciamo la prima di <lb/>quelle valide cagioni del progredir cos&igrave; straordinariamente le scienze, <lb/>nell'et&agrave;, che &egrave; soggetto della presente Parte del nostro Discorso. </s>

<s><lb/>A infonder nel vecchio albero, naturalmente esausto per la stra&shy;<lb/>boccante raccolta, rigoglio nuovo di vita, concorsero, in questa nuova <lb/>stagione felicemente congiunte le virt&ugrave; di Galileo e del Cartesio. </s>

<s><lb/>Cos&igrave; vennesi, nella cultura intellettuale, a conseguir quello stesso <lb/>intento e ad operar quel medesimo miracolo, che si vede operar <lb/>cos&igrave; spesso nella cultura fisica delle piante, quando a un tronco, <lb/>rimasto o infecondo, o di frutto insipido, s'inocula la vermena di <lb/>un albero, che dia frutto abbondante e squisito. </s>

<s>La Filosofia car&shy;<lb/>tesiana, che nell'et&agrave; precedente era rimasta di frutti sperimentali <lb/>cos&igrave; infeconda, inoculatasi, per mezzo dell'Analisi, alla Fisica gali&shy;<lb/>leiana, fecond&ograve; di nuovi e miracolosi parti la scienza. </s>

<s>S'aggiunse <lb/>poi di pi&ugrave; all'Analisi il Calcolo differenziale, che fu come un im&shy;<lb/>pennar d'ali il dorso a tentar voli pi&ugrave; arditi e pi&ugrave; sublimi: s'ag&shy;<lb/>giunse di pi&ugrave; l'uso di comporre e decomporre le forze, con la regola <lb/>del parallelogrammo, che fu, al dir del Frisi, come il filo d'Arianna, <lb/>da ritrovarsi in mezzo ai pi&ugrave; intricati laberinti della Meccanica. </s></p><p type="main">

<s>Gi&agrave;, fin dal primo rappresentarsi al pensiero e dalla lontana <lb/>questa nuova disposizione di cose, un mesto presentimento si sa&shy;<lb/>rebbe affacciato all'animo di un italiano, e gli avrebbe detto che, <lb/>al cambiarsi scena a questo terzo Atto del Dramma, si sarebbe anco <lb/>trasferito il luogo della rappresentazione fuori d'Italia. </s>

<s>L'Analisi, di <lb/>origine affatto straniera, il Calcolo differenziale di origine schietta&shy;<lb/>mente italiano, ma andato ad elaborarsi in Germania e in Inghil&shy;<lb/>terra, il principio della composizione delle forze, lasciato in dimen&shy;<lb/>ticanza da'Nostri com'inutile e anzi fallace strumento; bastavano a <lb/>confermar nell'animo que'mesti presentimenti di ci&ograve; che sarebbe <lb/>avvenuto, e che avvenne di fatto. </s>

<s>Il luogo della rappresentazione si <lb/>trasferisce d'Italia in Inghilterra, e alla persona di Galileo Galilei <lb/>succede quella d'Isacco Newton, a far le parti di Protagonista. </s></p><p type="main">

<s>La nuova successione per&ograve; non avvenne al solito modo, che <lb/>nell'Istituzione de'Principati aristotelico, galileiano, cartesiano: fu <lb/>insomma una pacifica e legittima successione, e non una battagliera <lb/>conquista. </s>

<s>Il Newton non ripudi&ograve; com'Aristotile, Galileo, il Cartesio, <lb/>le tradizioni scientifiche de'maggiori, e non pretese di farsi primo <lb/>e solo Maestro e Duce di coloro che sanno. </s>

<s>Riconobbe anzi il ma-<pb xlink:href="020/01/239.jpg" pagenum="220"/>gistero del grande nostro Italiano, ne segui fedelmente i metodi, e <lb/>ne accolse con amore e ne promosse gl'insegnamenti. </s></p><p type="main">

<s>Il Newton, come Galileo, non se ne st&agrave; che ai fatti. </s>

<s>Anch'egli <lb/>il tentar l'essenza l'ha per impresa non manco impossibile, e per <lb/>fatica non men vana nelle prossime sostanze elementari, che nelle <lb/>remotissime e celesti (Alb. </s>

<s>III, 462). Di quel che non ha potuto far <lb/>soggetto di sperimento ne parla come di cosa da questioni. <emph type="italics"/>Que&shy;<lb/>stioni<emph.end type="italics"/> infatti egli chiama quell'alto e sottil modo di speculare in&shy;<lb/>torno alle prime e pi&ugrave; recondite cause degli effetti naturali. </s>

<s>Cos&igrave; <lb/>fatte Questioni, trattando delle propriet&agrave; della luce, volle egli ac&shy;<lb/>cogliere tutte insieme, e perch&egrave; rappresentavano piuttosto le sue <lb/>proprie opinioni che la dimostrata certezza del vero, volle egli te&shy;<lb/>nerle separate e metterle come Appendice al suo Libro. </s></p><p type="main">

<s>Se qualcuno, per esempio, si fa a domandargli: che cos'&egrave; quel&shy;<lb/>l'attrazione, che tu poni per fondamento alla scienza del Cosmo? </s>

<s><lb/>Ed ei risponde: Un fatto osservato e confermato da leggi matema&shy;<lb/>tiche, il qual consiste in quel conato che fanno i corpi d'avvicinarsi <lb/>e di congiungersi insieme, dipenda egli un tal conato o da aliti <lb/>emessi, che commovano e sospingano i corpi, o dall'azion dell'etere, <lb/>che diffondendosi, prema, o dagli elaterii dell'aria o di altro mezzo <lb/>qualunque. (Principia Philos. </s>

<s>Coloniae 1760, T. I, pag. </s>

<s>464). </s></p><p type="main">

<s>Ma pure, soggiunge altrove, per dir qualche cosa della gravit&agrave; <lb/>e di questa misteriosa attrazione &ldquo; quaestionem unam de eius causa <lb/>investiganda subieci, quaestionem inquam, quippe qui experimentis <lb/>rem istam nondum habeam exploratam &rdquo; (Optices, Avvertim. alla <lb/>2. a ediz. del 1717).</s><s> La questione accennata &egrave; la XXI, nella quale <lb/>si ammette l'esistenza dell'etere cosmico, com'efficiente dell'attra&shy;<lb/>zione universale. </s></p><p type="main">

<s>E pur rispetto alla luce, com'entra il Newton in mezzo ai di&shy;<lb/>sputanti sull'essenza di lei? </s>

<s>Dop'aver, nella Sezione XIV del I Libro <lb/>dei <emph type="italics"/>Princippi,<emph.end type="italics"/> dimostrato che un minimo corpo vibrato e attratto <lb/>da un mezzo pi&ugrave; denso, vi descrive, penetrandolo addentro, una pa&shy;<lb/>rabola, per modo che il seno dell'angolo dell'incidenza serbi ragion <lb/>costante col seno dell'angolo dell'emergenza; soggiunge che s&igrave; fatte <lb/>attrazioni non sono molto dissimili da quelle, percui si riflette e si <lb/>rifrange la luce. </s>

<s>&mdash; Dunque anche la luce &egrave; un corpo? </s>

<s>&mdash; Sembre&shy;<lb/>rebbe di s&igrave;, risponde il Newton, giacch&egrave; ella si vede pure moversi <lb/>in tempo, com'&egrave; dimostrato dagli ecclissi dei satelliti di Giove, e <lb/>viene altres&igrave; attratta dai corpi, com'io stesso osservai nel fenomeno <lb/>grimaldiano. </s>

<s>Ma per&ograve; di questo io non voglio disputare, solo io <pb xlink:href="020/01/240.jpg" pagenum="221"/>dimostro matematimente correre una grande analogia fra le traiet&shy;<lb/>torie de'minimi corpi gettati e attratti dai mezzi diafani. </s>

<s>&ldquo; Nihil <lb/>omnium disputans, sed traiectorias corporum traiectoriis radiorum <lb/>persimiles solummodo determinans &rdquo; (Principia etc. </s>

<s>ibi, pag. </s>

<s>541). </s></p><p type="main">

<s>E quanto al modo cos&igrave; controverso del diffondersi la luce nello <lb/>spazio? </s>

<s>&mdash; Riguardando il Newton la luce come un fluido qualunque, <lb/>col principio della repulsione molecolare ne spiegava l'elasticit&agrave;, <lb/>della quale il grado s'argomentava per lui dal vederla correre tanto <lb/><figure id="id.020.01.240.1.jpg" xlink:href="020/01/240/1.jpg"/><lb/>veloce (Optices, quaest. </s>

<s>XXI). Cos&igrave; fatta elasticit&agrave;, come l'attrazione <lb/>verso i corpi taglienti e acuminati nel fenomeno grimaldiano, e le <lb/>traiettorie paraboliche descritte nel mezzo refringente dal raggio, <lb/>includevano senza dubbio l'ipotesi della <emph type="italics"/>emissione.<emph.end type="italics"/> L'Hook intanto <lb/>e l'Huyghens professavano un'ipotesi diversa, qual'era quella delle <lb/>ondulazioni eteree. </s>

<s>Ebbene: come si govern&ograve; il Newton in questo <lb/>negozio che era tanta parte del suo nuovo sistema ottico? </s>

<s>Trat&shy;<lb/>tandosi di cosa, da non si poter decidere con gli esperimenti, la <lb/>lascia a trattar nelle <emph type="italics"/>Questioni.<emph.end type="italics"/> Confessava ivi che il fosfeno nel-<pb xlink:href="020/01/241.jpg" pagenum="222"/>l'occhio compresso era molto favorevole all'ipotesi delle onde eteree <lb/>(quaest. </s>

<s>XVI), ma poi nella Questione XXVIII promuove contro <lb/>quella stessa ipotesi alcune difficolt&agrave;, la principale delle quali &egrave; <lb/>questa: Se la luce si diffondesse in onde, come il suono, dovrebbe, <lb/>a somiglianza di questo, insinuarsi anco dietro gli ostacoli, come si <lb/>pruova del suono delle campane, che si sente anco al di l&agrave; di un <lb/>monte &ldquo; At lumen nunquam compertum est vias incurvas ingredi, <lb/>nec sese in umbram inflectere (quest. </s>

<s>XXVIII). Volle forse perci&ograve; <lb/>il Newton asserir la verit&agrave; di quel moto vibrante della luce, a cui <lb/>applic&ograve; i teoremi dimostrati in fine del suo I Libro dei <emph type="italics"/>Principii?<emph.end type="italics"/><lb/>Ecco quel che egli si contenta di dire, nella XXIX Questione: &ldquo; An <lb/>non radii luminis exigua sunt corpuscula a corporibus lucentibus <lb/>emissa? </s>

<s>&rdquo; </s></p><p type="main">

<s>Parimenti intorno all'origine e a'fenomeni presentati dalla coda <lb/>delle comete, non ha appena il Newton accennato alla sua ipotesi, <lb/>che cio&egrave; sia quella coda una esalazione fumosa del corpo della stessa <lb/>cometa, respinta per circumpulsione dal centro del Sole, come i <lb/>nostri fumi si vedono esser respinti dal centro della Terra; che <lb/>egli tosto soggiunge: &ldquo; Ceterum rerum naturalium causas reddere <lb/>non est huius instituti &rdquo; (Opusc. </s>

<s>Lausannae 1744. T. II, pag. </s>

<s>58). </s></p><p type="main">

<s>Che poi il Newton prosegua veramente i metodi stessi di Ga&shy;<lb/>lileo non vorremmo dedurlo dal citar ch'ei fa il nome di lui cos&igrave; <lb/>spesso e con amore. </s>

<s>Quelle citazioni anzi rivelano che il Filosofo <lb/>inglese non attinse le dottrine del Nostro, alla loro sorgente. </s>

<s>Cos&igrave; <lb/>per esempio, dop'avere stabilito, per prima legge del moto, l'inerzia <lb/>della materia e gli effetti proporzionali alle forze motrici, col pa&shy;<lb/>rallelogrammo delle forze posto per corollario di quelle stesse leggi, <lb/>soggiunge: &ldquo; per leges duas primas et corollaria duo primo, Galileus <lb/>invenit descensum gravium esse in duplicata ratione temporum. <lb/>(Principia, ibi, pag. </s>

<s>45). Ma Galileo tenne, in dimostrare quel teo&shy;<lb/>rema, altri metodi. </s>

<s>Quello accennato ivi dal Newton &egrave; il metodo <lb/>dell'Huyghens, da cui il Newton stesso par che attingesse le dot&shy;<lb/>trine galileiane. </s>

<s>Vorremmo dire piuttosto che nel Professore di <lb/>Cambridge si trasfuse lo spirito del Professore di Padova, il quale <lb/>vi trov&ograve; gli organi pi&ugrave; acconci al suo perfezionamento, e pi&ugrave; adulte <lb/>ed esercitaie le membra. </s></p><p type="main">

<s>D'onde avesse i primi aliti quello spirito, i nostri Lettori lo <lb/>sanno, e la Filosofia neutoniana segnal&ograve; la pi&ugrave; compiuta vittoria, <lb/>che, sopra Aristotile, abbia conseguita Platone, sul campo della <lb/>scienza. </s>

<s>La Filosofia peripatetica, nuovamente apparita a sedurre <pb xlink:href="020/01/242.jpg" pagenum="223"/>gl'ingegni con la lusinghiera eloquenza cartesiana, ebbe nel Newton <lb/>la sua piena sconfitta, quando nel suo Libro immortale dimostr&ograve; che <lb/>la Natura geometrizza veramente a modo platonico, e non fantastica <lb/>a modo aristotelico. </s>

<s>Che, nel dare a quel Libro il titolo di <emph type="italics"/>Prin&shy;<lb/>cipia mathematica Philosophiae<emph.end type="italics"/> non pensasse il Filosofo inglese di <lb/>contrapporre, infino dal frontespizio, l'opera sua dimostrata, e quel&shy;<lb/>l'altra immaginata dal Filosofo Bretone, con simil titolo di <emph type="italics"/>Prin&shy;<lb/>cipia Philosophiae;<emph.end type="italics"/> non par credibile, bench&egrave;, senza rivolgersi n&egrave; a <lb/>destra n&egrave; a sinistra, l'Autore della Nuova filosofia matematica pro&shy;<lb/>ceda a diritto per la sua via. </s>

<s>Rogero Cotes per&ograve;, in quel suo bel <lb/>Discorso premesso alla seconda edizione dei Principii neutoniani, <lb/>non tace del mal animo, con cui questi stessi Principii furon veduti <lb/>da'seguaci del Cartesio, i quali sentivan pur troppo com'esalasse da <lb/>quelle pagine uno spirito di verit&agrave;, potente a cacciar via i nuvolosi <lb/>errori del loro Maestro. </s></p><p type="main">

<s>Dal Cartesio il Newton apprese l'analisi, e va anzi debitore a <lb/>lui se riusc&igrave; a instituire il calcolo differenziale, e ad applicarlo cos&igrave; <lb/>utilmente alla Fisica sperimentale galileiana. </s>

<s>Giova infatti osservare <lb/>che il Calcolo differenziale ebbe origine dall'applicar l'Analisi car&shy;<lb/>tesiana alla Geometria degli indiv&icirc;sibili del Cavalieri, e perci&ograve; non <lb/>sarebbe il Newton, o il Leibniz che ne sia l'Autore, potuto riuscir <lb/>felicemente a quella nuova istituzione, se il Cartesio non mostrava <lb/>come si potesse l'Algebra comporre colla Geometria. </s></p><p type="main">

<s>L'inspirazione poi del proprio genio, meglio che i pochi esempii <lb/>dell'Huyghens, fu che fece presentire al Newton la fecondit&agrave; del <lb/>metodo di comporre e decomporre le forze colla regola del parel&shy;<lb/>logrammo insegnata dall'Herigonio. </s>

<s>I discepoli di Galileo, fra'quali <lb/>il Borelli, riputarono sventuratamente quella regola fallace, e l&agrave; dove <lb/>avrebbero potuto procedere per via diretta e spedita a risolvere <lb/>astrusi problemi di Meccanica, s'avvolsero spesso, come si mostrer&agrave; <lb/>per gli esempii a suo luogo, in incredibili paralogismi. </s>

<s>Ma il Newton, <lb/>con libero ingegno non preoccupato da pregiudizii di scuola, n&egrave; <lb/>soggiogato dall'autorit&agrave; di Galileo, riconobbe invece che quella re&shy;<lb/>gola erigoniana era verissima, e sentenzi&ograve; e dimostr&ograve; di fatto nel <lb/>corollario II alle leggi del moto premesse ai <emph type="italics"/>Principii matematici,<emph.end type="italics"/><lb/>che la regola prescritta dall'Herigonio per comporre e decomporre <lb/>le forze <emph type="italics"/>abunde confirmatur ex Mechanica.<emph.end type="italics"/></s></p><p type="main">

<s>Cos&igrave; alle virt&ugrave; ereditate da Galileo s'aggiunsero, nel Filosofo <lb/>britanno, le tre nuove potenze enumerate, per cui s'inizi&ograve; e si co&shy;<lb/>stitu&igrave; questo nuovo e cos&igrave; splendido Principato della scienza. </s>

<s>Prin-<pb xlink:href="020/01/243.jpg" pagenum="224"/>cipato glorioso, che il Newton consegu&igrave; felicemente senza troppo <lb/>dissipar le valide forze a difendersi contro i nemici, e senza tanto <lb/>arrovellarsi a riconquistar le proprie scoperte dagli arditi usurpa&shy;<lb/>tori. </s>

<s>Qualche sua semplice lettera basta a far tacere il Cassegrain, <lb/>che pretendeva un diritto di anteriorit&agrave; nell'invenzione del canoc&shy;<lb/>chiale catadiottrico, e un inciso, con cui cominci&ograve; lo scolio della <lb/>quarta proposizione del libro primo de'<emph type="italics"/>Principii,<emph.end type="italics"/> parve assai a <lb/>sodisfare il Wrenn, l'Hook e l'Halley de'pretesi meriti loro con&shy;<lb/>cernenti la teoria delle forze centrali. </s></p><p type="main">

<s>Chi, dalle onorificenze tributate anche in vita al Newton, passa <lb/>a considerare le persecuzioni che ebbe anche dopo morte a patir <lb/>Galileo, o maledice arrabbiatamente alla malignit&agrave; e all'ingiustizia <lb/>degli uomini, o pi&ugrave; rassegnato invoca un destino cieco distributore <lb/>a chi di sventure a chi di favori. </s>

<s>Noi crediamo invece che sia l'uo&shy;<lb/>mo stesso, il quale operando in un modo piuttosto che in un altro, <lb/>ora induce gli altri uomini a favorirlo, e ora al contrario gli pro&shy;<lb/>voca a perseguitarlo. </s>

<s>Se anco il Newton, come Galileo, se la fosse <lb/>voluta prendere con quello e con questo, non gli sarebbero, senza <lb/>dubbio, in Inghilterra e nel secolo XVIII, mancate persecuzioni e <lb/>sventure. </s>

<s>Tutto altrimenti, egli aborriva dall'attaccar brighe con <lb/>chicchessia, e per non aver che dire con l'Hook, uomo litigioso, <lb/>tenne per tredici anni il celebre suo Trattato dell'Ottica rinchiuso <lb/>e avvolto nel manoscritto. </s></p><p type="main">

<s>Pur troppo &egrave; vero che non &egrave; da fare il confronto fra Galileo, <lb/>che ebbe a fondare il suo Regno a mano armata, contro i Peripa&shy;<lb/>tetici, e il Newton, che ricev&egrave; quel Regno di gi&agrave; stabilito, e che <lb/>non aveva bisogno d'altro che d'essere ampliato. </s>

<s>Pur troppo si <lb/>potrebbero dir tante altre cose, a intrigar piuttosto che a risolvere <lb/>la questione, e perci&ograve;, lasciando d'investigar questi, che anche noi <lb/>chiameremo destini della vita o civile o morale, passeremo a veder <lb/>del Newton i principii e i progressi della vita intellettuale, e <lb/>qual'efficace concorso v'abbiano avuto le tradizioni scientifiche dei <lb/>nostri italiani. </s></p><p type="main">

<s><emph type="center"/>II.<emph.end type="center"/></s></p><p type="main">

<s>All'entrar dell'anno 1666 era in Cambridge tutto intento a <lb/>lavorare i vetri da canocchiali, studiandosi con ogni artificio di <lb/>configurarli in quella nuova foggia di superficie o paraboliche o <pb xlink:href="020/01/244.jpg" pagenum="225"/>iperboliche, le quali un'antica tradizione veniva predicando per le <lb/>pi&ugrave; accomodate a produr l'effetto di avvalorare la virt&ugrave; visiva, <lb/>nonostante che il laborioso esercizio fosse stato dimostrato inutile <lb/>dal Cavalieri. </s>

<s>Cos&igrave;, trattando i cristalli, venne voglia al Newton di <lb/>preparare uno di quei prismi triangolari, per dilettarsi nella pia&shy;<lb/>cevole contemplazione degli svariati e splendidi colori. </s>

<s>Chiuse perci&ograve; <lb/>la finestra di camera e aperto un foro nell'imposta, riceveva per <lb/>esso un raggio di sole, che, rifranto nel prisma, andava a dipingere <lb/>lo spettro colorato sopra una carta bianca. </s>

<s>Si sarebbe aspettato di <lb/>veder quello spettro dipinto in figura circolare com'era il foro, e <lb/>trova con sua gran maraviglia che si distende invece allungato in <lb/>figura di una striscia, la quale, misurata diligentemente, riesce lunga <lb/>cinque tanti, presso a poco, quant'ella &egrave; larga. </s>

<s>Ne osserva le due <lb/>estremit&agrave;, e gli sembran terminare in un arco di cerchio. </s>

<s>Il raggio, <lb/>dunque, conclude, ha subito, attraversando il prisma, una disper&shy;<lb/>sione, e ci&ograve; senza dubbio per essere alcune parti di quello stesso <lb/>raggio pi&ugrave; refrangibili di alcune altre &ldquo; Unde patet veram imaginis <lb/>sic exporrectae causam hanc unam esse quod scilicet lux constat <lb/>ex radiis, quorum alii aliis magis refrangibiles sunt &rdquo; (Op. </s>

<s>omn. </s>

<s>opt. </s>

<s><lb/>Patavii 1773, App. </s>

<s>pag. </s>

<s>5). </s></p><p type="main">

<s>Il primo frutto che raccolse da questa scoperta, fu quello di <lb/>abbandonare ogni speranza di dover giungere alla desiderata per&shy;<lb/>fezione del canocchiale diottrico, avendo ben conosciuto che, anco <lb/>quando fosse riuscito a trovar la figura del perfetto concorso, quel <lb/>concorso, nonostante, non avrebbe mai avuto il suo effetto, &ldquo; quia <lb/>lux ipsa est mixtura quaedam heterogenea composita ex radiis di&shy;<lb/>versae refrangibilitatis. </s>

<s>&rdquo; Il secondo frutto che si credette di poter <lb/>raccoglier l'Autore dalla sua scoperta, fu quello di aver finalmente <lb/>riconosciuta l'origine e le propriet&agrave; de'colori. </s>

<s>Non son dunque i <lb/>colori, concludeva il Newton, qualificazioni della luce nate dalle <lb/>riflessioni o dalle rifrazioni de'corpi naturali, come volgarmente si <lb/>crede, &ldquo; sed primigeniae et congenitae proprietates in diversis ra&shy;<lb/>diis diversae. </s>

<s>Aliqui radii tantum ad rubrum, alii solum ad flavum, <lb/>alii ad viridem effingendum apti sunt &rdquo; (ibi, pag. </s>

<s>6). E nella seconda <lb/>Parte delle Lezioni Ottiche, riserbata a trattar di proposito <emph type="italics"/>De co&shy;<lb/>lorum origine,<emph.end type="italics"/> accenna alle due principali ipotesi peripatetica e <lb/>cartesiana seguitate da tutti prima di lui, e mostra quanto fosser <lb/>lontane dalla verit&agrave; delle cose. </s></p><p type="main">

<s>Che prima del Newton si seguisse in generale dagli Ottici <lb/>l'ipotesi di Aristotile, secondo la quale i colori si generano da una <pb xlink:href="020/01/245.jpg" pagenum="226"/>proporzionata mistura d'ombra e di luce, &egrave; vero, e fu quell'ipotesi <lb/>accolta anche dagli Accademici del Cimento. </s>

<s>Il Viviani ha lasciato <lb/>fra'suoi Manoscritti una schedula autografa, nella quale, assegnati <lb/>i due estremi del bianco e del nero, fa nascere il rosso dalla mi&shy;<lb/>stura di sei gradi di bianco con uno di nero, il ranciato da cinque <lb/>gradi di bianco mescolato con due di nero, e cos&igrave; gradatamente <lb/>per tutti e sette i colori dello spettro. </s>

<s>Nonostante, anche prima del <lb/>Newton, si trovano in alcuni Autori italiani ipotesi nuove e pi&ugrave; giu&shy;<lb/>diziose e conformi ai fatti, delle antiche peripatetiche. </s>

<s>Il Maurolico, <lb/>per esempio, aveva, nel Teorema XVIII del primo libro <emph type="italics"/>Diapha&shy;<lb/>norum,<emph.end type="italics"/> dimostrato l'aberrazione di sfericit&agrave; delle lenti, al qual teo&shy;<lb/>rema, se avesse atteso il Newton, avrebbe lasciato assai prima di <lb/>travagliarsi intorno a'canocchiali diottrici, e pi&ugrave; per tempo si sa&shy;<lb/>rebbe rivolto ai canoccbiali per riflessione. </s>

<s>Il Maurolico stesso, ri&shy;<lb/>fiutando i placiti aristotelici, fu primo a dir che i colori avevano <lb/>origine dalla luce, la quale rifrangendosi, si trova in varie parti dello <lb/>spettro pi&ugrave; o men costipata; dottrina insegnata pure dall'Imperato <lb/>o dallo Stelliola, dodici anni prima che fosse nota al pubblico la <lb/>Diottrica del celebre Abate di Santa Maria in Porto. </s>

<s>E f&ugrave; l'Impe&shy;<lb/>rato, che pi&ugrave; di un mezzo secolo prima del Newton, quando il <lb/>prisma triangolare non serviva ad altro che alle piacevoli ricrea&shy;<lb/>zioni, ei lo predic&ograve; <emph type="italics"/>strumento di refrazione all'osservazione della <lb/>generazion dei colori tra gli altri tutti ottimo<emph.end type="italics"/> (Hist. </s>

<s>nat. </s>

<s>Venezia <lb/>1672, pag. </s>

<s>294). Le dottrine ottiche dei due nostri italiani furono <lb/>poi dal Bullialdo divulgate nella XXIX proposizione del suo celebre <lb/>Trattato <emph type="italics"/>De natura lucis,<emph.end type="italics"/> e pi&ugrave; solennemente poi sanzionate dal <lb/>Grimaldi; dottrine ottiche, le quali, convenendo colle neutoniane <lb/>in professar che i colori non riseggan nei corpi e in dir che non <lb/>sian luce in potenza, come teneva il Keplero, ma che sian la luce <lb/>stessa in atto; ne differivan solo in ammettere una <emph type="italics"/>costipazione<emph.end type="italics"/><lb/>de'raggi rifratti, invece di una <emph type="italics"/>dispersione.<emph.end type="italics"/></s></p><p type="main">

<s>La scoperta della dispersion della luce ne'prismi triangolari, <lb/>e la
nuova teoria de'colori che indi ne segue, furono pubblicate <lb/>dall'Autore in una Epistola stampata prima in Cambridge e inse&shy;<lb/>rita pochi anni dopo nel n. o 80 delle <emph type="italics"/>Transazioni filosofiche<emph.end type="italics"/> di <lb/>Londra, sotto il d&igrave; 19 Febbraio 1672. </s><s>Appena furon divulgate le <lb/>nuove dottrine, il gesuita Ignazio Pardies si mosse incontro ad <lb/>oppugnarle, dicendo che l'allungamento dello spettro colorato non <lb/>dipendeva da una dispersione per via del vario grado di refrangi&shy;<lb/>bilit&agrave; del raggio composto, come voleva il Newton, ma avveniva per <pb xlink:href="020/01/246.jpg" pagenum="227"/>un fenomeno somigliantissimo a quello osservato gi&agrave; e descritto nel <lb/>Trattato <emph type="italics"/>De Lumine<emph.end type="italics"/> dal Grimaldi. </s>

<s>Ecco annunziarsi il titolo di un <lb/>libro, ecco pronunziarsi il nome di un Italiano, a cui il Filosofo <lb/>inglese va debitore della sua gloria. </s>

<s>Cos&igrave; i voli sublimi distesi pel <lb/>grandissimo mondo, come le sottili penetrazioni addentro alle chiuse <lb/>e buie regioni del piccolissimo, ebbero occasione dal rimeditar che <lb/>fece il Newton le pagine di quel libro. </s></p><p type="main">

<s>Veniva insomma il Pardies, operando i soliti benefici effetti di <lb/>tutti gli oppositori, a far provvidamente capitare a Cambridge il <lb/>Trattato <emph type="italics"/>De Lumine<emph.end type="italics"/> stampato in Bologna, e colui che sentiva con&shy;<lb/>trapporre alle sue nuove, altre nuove scoperte annunziate in quel <lb/>Trattato, non poteva non ricercarvele dentro avidamente. </s>

<s>Legge alla <lb/>prima apertura del Volume che l'Autore, oltre alle riflessioni e alle <lb/>rifrazioni, ammette nella luce una terza passione, che egli appella <lb/>col nome nuovo di <emph type="italics"/>diffrazione.<emph.end type="italics"/> Tutto attento ha il pensiero sopra <lb/>i due esperimenti ivi descritti a dimostrare in che modo un raggio <lb/>luminoso, che rasenta gli orli di un corpo opaco, vi si diffrange. </s>

<s><lb/>Ripete in altra maniera l'esperimento, e trova che di fatto l'ombre <lb/>riescon sempre alquanto maggiori di quel che se il raggio proce&shy;<lb/>desse a diritto. </s>

<s>Non ci &egrave; dubbio dunque: ei si diffrange. </s>

<s>Ma qual'&egrave; <lb/>la causa di quella diffrazione? </s>

<s>Il Grimaldi, contento a descrivere <lb/>il fatto, non lo dice: la risposta data da altri interrogati in propo&shy;<lb/>sito, che cio&egrave; risegga la causa del fenomeno nelle solite rifrazioni <lb/>dell'aria, non sodisfa il sagace investigatore. </s>

<s>Gli balena alla mente <lb/>un pensiero ardito: che il raggio si diffranga perch&egrave; &egrave; attratto dagli <lb/>orli taglienti del corpo opaco interposto? </s>

<s>&ldquo; Annon corpora agunt <lb/>in lumen interiecto aliquo intervallo, suaque illa actione radios eius <lb/>inflectunt? </s>

<s>&rdquo; (Optices, Lib. </s>

<s>III, quaest. </s>

<s>I). </s></p><p type="main">

<s>L'ardita ipotesi per&ograve; supponeva risoluta gi&agrave; la gran questione <lb/>della natura della luce, se cio&egrave; essa sia corporea e soggetta alle <lb/>passioni stesse degli altri corpi ponderosi. </s>

<s>La legge delle rifrazioni <lb/>conclusa dalla meccanica, specialmente in Italia, dai pi&ugrave; si ripu&shy;<lb/>diava, e, per tante prove fatte, non s'era ancora riusciti ad assi&shy;<lb/>curarsi se un raggio luminoso si muove in tempo o si diffonde in <lb/>istante. </s>

<s>Il Grimaldi per&ograve; tenne per risoluta la gran questione, e <lb/>posto per cosa certa che fosse anche la luce un corpo come tutti <lb/>gli altri, ammise, anteriormente a qualunque dimostrazione speri&shy;<lb/>mentale, che ella si movesse in tempo. </s>

<s>Applicando poi al moto di <lb/>lei la legge della velocit&agrave; in ragion reciproca delle sezioni, come <lb/>segue nel moto di tutti i fluidi, riusc&igrave; a concludere, in modo sicuro, <pb xlink:href="020/01/247.jpg" pagenum="228"/>che i seni degli angoli d'incidenza hanno ragion costante co'seni <lb/>degli angoli di refrazione. </s></p><p type="main">

<s>L'esempio del Grimaldi e la felice scoperta del Roemer per&shy;<lb/>suasero il Newton della natura corporea della luce, il quale anzi <lb/>tanto oltre and&ograve;, che, ammettendo un nucleo duro in tutte le par&shy;<lb/>ticelle componenti ogni sorta di corpi, non dubit&ograve; di soggiungere: <lb/>&ldquo; quin et ipsi etiam radii luminis corpora dura esse videntur &rdquo; (ibi, <lb/>quaest. </s>

<s>XXXI). E mentre i discepoli di Galileo avevano adombrato <lb/>e recalcitrato contro la Meccanica ottica del Cartesio e dell'Heri&shy;<lb/>gonio, egli incomincia i suoi studii sopra la luce, applicando alla <lb/>stessa, nella Sez. </s>

<s>XIV del I Libro de'<emph type="italics"/>Principii,<emph.end type="italics"/> le propriet&agrave; delle <lb/>traiettorie paraboliche, che Galileo avea dimostrato venir descritte <lb/>da tutti i corpi gravi proietti. </s></p><p type="main">

<s>Ma sia pure la luce un corpo duro, s'ammetta pur possibile <lb/>che la diffrazione avvenga perch&egrave; le molecole dure della luce ven&shy;<lb/>gono attratte dalle molecole dure che circondan gli orli del foro <lb/>nel fenomeno grimaldiano: con quali argomenti si possono dimo&shy;<lb/>strare o si possono almeno render credibili queste cose tanto lon&shy;<lb/>tane dalla comune opinione? </s></p><p type="main">

<s>Ecco aprirsi di qui la via a nuove e peregrine speculazioni, <lb/>dalle quali sarebbe per esser promossa tant'oltre la scienza nel <lb/>secolo XVIII. Galileo, nel Discorso intorno alle galleggianti, non <lb/>pensando alle pressioni idrostatiche, dalle quali si sostengono alla <lb/>superficie le tavolette di gravit&agrave; specifica maggiore dell'acqua, si <lb/>ridusse ad ammettere una specie di attrazione fra l'aria e la su&shy;<lb/>perficie solida del galleggiante. </s>

<s>E di li pass&ograve; a specular la ragione <lb/>di quella copula, che tiene unite insieme le minime particelle dei <lb/>corpi, attribuendola a una indefinita virt&ugrave; calamitica del contatto, <lb/><emph type="italics"/>senza interposizione alcuna di fluidi cedenti<emph.end type="italics"/> (Alb. </s>

<s>XII, 54). Per&shy;<lb/>suaso poi, dalle opposizioni giustissime che gli furon fatte, dell'in&shy;<lb/>sufficienza e anzi della falsit&agrave; del suo principio, neg&ograve; nel Saggiatore <lb/>(Alb. </s>

<s>IV. 299) quella virt&ugrave; dell'attrazione calamitica dell'aria che <lb/>aveva prima ammessa come causa del sostenersi le tavolette d'ebano, <lb/>non bagnate, sulla superficie dell'acqua, e finalmente, nel I Dialogo <lb/>dello Due Nuove Scienze, tornato a specular sul fatto dell'adesione <lb/>di due marmi venuti fra loro a squisito contatto, e sulla virt&ugrave; co&shy;<lb/>pulatrice della materia, non dubit&ograve; di riconoscer nella forza del <lb/>vacuo la causa generalissima di questo effetto (Alb. </s>

<s>XIII. pag. </s>

<s>22, 23). </s></p><p type="main">

<s>Quando poi al vacuo si sostitu&igrave; la pressione ammosferica, oc&shy;<lb/>corse in tal proposito un fatto singolare nella storia delle scienze. <pb xlink:href="020/01/248.jpg" pagenum="229"/>Il Boyle aveva sottoposto alla campana della sua macchina pneu&shy;<lb/>matica uno strumento simile al termometro ad aria, se non che <lb/>tutto, cannello e bulbo, era pieno di acqua sostenuta, come si sa, <lb/>dalla pressione dell'aria sulla superficie del liquido, dentro a cui <lb/>il cannello stesso, con la sua bocca, era immerso. </s>

<s>Fatto perci&ograve; il <lb/>vuoto, se questo fosse riuscito assoluto, la caraffella piena d'acqua <lb/>si sarebbe dovuta votare affatto. </s>

<s>Ma perch&egrave; qualche poco di liquido <lb/>seguitava ancora a sostenersi a mezzo il cannello, il Boyle diceva <lb/>avvenir ci&ograve; perch&egrave; &egrave; impossibile colla macchina estrar tutta l'aria, <lb/>e farvi sotto la campana il vuoto perfetto. </s></p><p type="main">

<s>Venne voglia all'Huyghens di ripetere l'esperienza boileiana, <lb/>e trov&ograve; che il caso descritto dall'Autore non si avverava se non che <lb/>quando l'acqua tien dentro a s&egrave; sciolta qualche particella d'aria. </s>

<s><lb/>Sperimentando coll'acqua bollita, anco fatto il vuoto, vide con sua <lb/>gran maraviglia che la caraffella seguitava tuttavia a rimaner piena. </s>

<s><lb/>Divulgato il fatto, non gli si voleva credere, per cui l'Huyghens <lb/>stesso nel 1663, indusse la Societ&agrave; Reale di Londra a ripetere so&shy;<lb/>lennemente l'esperienza. </s>

<s>V'era fra gli altri presente lo stesso Boyle, <lb/>sorpreso da tanto stupore, a veder davvero la caraffella rimaner <lb/>piena, che quasi non credeva a'suoi proprii occhi. </s>

<s>Volle che ivi, <lb/>prima di sciogliere l'Adunanza, fosse fatta l'esperienza col mercurio <lb/>nel consueto strumento torricelliano di cannello assai stretto, e si <lb/>vide il liquido, solido ridursi ai 27 e 28 pollici, rimaner sostenuto <lb/>a 52 e talvolta anco infino a 75. </s></p><p type="main">

<s>A spiegar questo e altri simili fatti straordinari, fra'quali quello <lb/>di due lastre di vetro che seguitano ad aderire nel vuoto, l'Huy&shy;<lb/>ghens, ne'suoi <emph type="italics"/>Esperimenti fisici,<emph.end type="italics"/> si ridusse ad ammetter che sotto <lb/>la campana della macchina pneumatica, estratta l'aria, rimanesse <lb/>un corpo pi&ugrave; ponderoso di lei, l'etere, causa straordinaria di quegli <lb/>effetti (Opera Varia, Lugd. </s>

<s>Batav. </s>

<s>1724, pag. </s>

<s>769-76). </s></p><p type="main">

<s>Era dunque il Newton sopra pensiero di trovare argomenti, <lb/>onde render probabile, se non dimostrata la reciproca attrazione <lb/>fra le minime particelle de'corpi, e applicarla a spiegare i fatti <lb/>della diffrazion della luce, da lui stesso confermati con nuovi espe&shy;<lb/>rimenti; quando gli occorse di tornar sopra con maggiore atten&shy;<lb/>zione all'esperienza ugeniana ora narrata, e sopra l'ipotesi imma&shy;<lb/>ginata per ispiegarla. </s>

<s>Quell'ipotesi dell'etere ponderoso, che riman <lb/>dopo estratta l'aria, era merce introdotta dal Cartesio antivacuista, <lb/>e l'Huyghens la gabell&ograve; perch&egrave; favoriva le teorie, che insiem con <lb/>l'Hook professava intorno alla luce. </s>

<s>Al Newton per&ograve; a cui l'ipotesi <pb xlink:href="020/01/249.jpg" pagenum="230"/>dell'etere ponderante sapeva dell'immaginario, venne in pensiero <lb/>che il sostenersi i liquidi ne'cannelli stretti sopra il naturale livello <lb/>dipendesse piuttosto da quella attrazion molecolare, di cui andava <lb/>sagacemente investigando argomenti, che servissero di prova spe&shy;<lb/>rimentale. </s></p><p type="main">

<s>E non questi fatti soli, ma tutta la serie percorse dei cos&igrave; detti <lb/>fenomeni capillari, che ritrovaron tutti la loro adeguata ragione <lb/>nell'attrarsi vicendevolmente le molecole fra solidi e liquidi. </s>

<s>Lo <lb/>stesso agglomerarsi delle minime gocciole dell'acqua, o campate <lb/>libere in aria o posate sopra superficie a cui il liquido non aderisce, <lb/>serv&igrave; al Newton di valido argomento a dimostrar l'effetto dell'at&shy;<lb/>trazione molecolare prevalente intorno al centro di figura. </s>

<s>Niccol&ograve; <lb/>Aggiunti aveva introdotto un <emph type="italics"/>moto occulto<emph.end type="italics"/> dell'acqua, senza per&ograve; <lb/>determinare la natura di questo moto. </s>

<s>Donato Rossetti era gi&agrave; ri&shy;<lb/>corso a un <emph type="italics"/>istinto di appetenza,<emph.end type="italics"/> col quale felicemente spiegava <lb/>alcuni fatti de'pi&ugrave; singolari, ma il Filosofo inglese generalizz&ograve; la <lb/>teoria delle forze attrattive molecolari e la rend&egrave; compiuta colla <lb/>dualit&agrave; contrapposta delle repulsioni &ldquo; Et sicut in algebra ubi quan&shy;<lb/>titates affermativae evanescunt et desinunt, ibi negativae incipiunt; <lb/>ita in mechanicis ubi attractio desinit, ibi vis repellens succedere <lb/>debet &rdquo; (Optices, Lib. </s>

<s>III, quaest. </s>

<s>XXXI). D'onde, soggiunge il <lb/>Newton, ne conseguitano gli effetti della emission della luce e la <lb/>risoluzione de'corpi solidi in sostanze aerose e in vapori, impe&shy;<lb/>rocch&egrave; le particelle de'corpi, distratte o dalla forza del calore o <lb/>dalla agitazione intestina delle fermentazioni, tosto che sono uscite <lb/>dalla sfera dell'attrazione del loro centro, se ne dilungano con <lb/>grand'impeto, e rifuggono di tornarci di nuovo. </s>

<s>Cos&igrave; produconsi <lb/>quelle violente espansioni, che si vedono in tante volgari esperienze, <lb/>parendo impossibile che sia contratta in un granello di polvere <lb/>quell'aria, che s'espande in un volume centinaia e migliaia di volte <lb/>maggiore. </s>

<s>&ldquo; Quae tam ingens contractio et expansio animo sane <lb/>concipi vix potest, si particolae aeris fingantur elasticae et ramosae, <lb/>vel viminum lentorum intra se in circulos intortorum instar esse, <lb/>vel ulla alia ratione, nisi ita si vim repellentem habent, qua a se <lb/>mutuo fugiant &rdquo; (ibi). </s></p><p type="main">

<s>Da queste immortali pagine neutoniane si sente alitare uno <lb/>spirito nuovo che vivifica; si vede aprirsi un chiarore di luce che <lb/>rallegra l'intelletto offuscato dalla nebbia cartesiana. </s>

<s>Anche nella <lb/>scienza del mondo dei piccolissimi, sopra Aristotile, trionfa Platone: <lb/>alle finzioni peripatetiche sottentra la legge matematica. </s>

<s>E perch&egrave; <pb xlink:href="020/01/250.jpg" pagenum="231"/>il mondo dei piccolissimi riconosce il medesimo Autore, e soggiace <lb/>alle medesime leggi del Mondo dei grandissimi, ecco uscire le spe&shy;<lb/>culazioni del Newton dalle angustie che intercedono fra un atomo <lb/>e l'altro, e risalir con ardito volo per gli spazii smisurati del cielo. <lb/></s>

<s>&ldquo; Atque haec quidem omnia si ita sint, iam Natura universa valde <lb/>erit simplex et consimilis sui: perficiens nimirum magnos omnes <lb/>corporum coelestium motus attractione gravitatis, quae est multa <lb/>inter corpora illa omnia, et minores fere omnes particularum sua&shy;<lb/>rum motus alia aliqua vi attrahente et repellente, quae est inter <lb/>particulas illas mutuas &rdquo; (ibi). </s></p><p type="main">

<s>Ecco il discepolo di Platone e di Galileo, che nella semplicit&agrave; <lb/>degli ordini matematici ritrova le leggi universali della natura, fa&shy;<lb/>ticosamente cercate da Aristotile e dal Cartesio nell'arguzie de'loro <lb/>cervelli. </s>

<s>Gian Alfonso Borelli aveva impresse larghe e profonde <lb/>orme per quella via platonica, la quale fu anzi prima aperta da <lb/>lui, introducendo la matematica semplicit&agrave; delle forze centrali. </s>

<s>Ma <lb/>poi, sedotto dall'autorit&agrave; del Keplero, si dette a fantasticare pue&shy;<lb/>rilmente intorno ai pianeti galleggianti nell'etere, e non seppe sco&shy;<lb/>prire il gran paralogismo che commetteva l'Astronomo alemanno, <lb/>quando concludeva che l'intensit&agrave; della luce, al diffondersi della <lb/>quale si rassomigliava il diffondersi delle forze impulsive del sole; <lb/>scemasse a proporzione che crescono le semplici distanze. </s>

<s>E tanto <lb/>fu sottile l'inganno, che vi rimase colto anche il Newton, quando <lb/>la prima volta istitui il calcolo della velocit&agrave;, con cui sarebbe ca&shy;<lb/>duta la Luna, se fosse veramente attratta, com'ei supponeva, al <lb/>centro della Terra. </s></p><p type="main">

<s>Il Bullialdo, procedendo conforme alle vere regole della Foto&shy;<lb/>metria, s'era maravigliato grandemente dell'errore, in che vedeva <lb/>essere incorso il Keplero, e aveva concluso che la luce decresce in <lb/>intensit&agrave;, non a proporzione che crescono le semplici distanze, ma <lb/>i quadrati delle distanze. </s>

<s>E ci&ograve; dette occasione all'Hook e all'Halley <lb/>d'applicar la medesima legge al decrescer l'intensit&agrave; delle forze <lb/>attrattive. </s>

<s>Pervenuta quella notizia alle orecchie del Newton, gli <lb/>parve la nuova legge assai ragionevole, e tornato ad applicarla al <lb/>calcolo della velocit&agrave;, con cui sarebbe verso noi caduta la Luna, <lb/>trov&ograve; che quello stesso calcolo rispondeva esattamente all'ipotesi <lb/>dell'attrazione. </s>

<s>Applicato poi ed esteso, dalla Luna a tutti gli altri <lb/>sistemi, quel principio dell'attrazione divenne universale. </s>

<s>Per ultimo <lb/>suggello, che la semplicit&agrave; e uniformit&agrave; della legge scoperta era <lb/>conforme alla verit&agrave; delle cose, il Newton applic&ograve; quel principio <pb xlink:href="020/01/251.jpg" pagenum="232"/>alla teoria delle comete, alla precessione degli equinozii, alla nu&shy;<lb/>tazione de'poli, al flusso e riflusso del mare, a spiegare insomma <lb/>i pi&ugrave; astrusi e reconditi misteri. </s></p><p type="main">

<s>Porre il flusso marino nel numero de'pi&ugrave; astrusi misteri, non <lb/>parr&agrave; alieno dal vero a chi ripensi quanto sottilmente vi stillassero <lb/>attorno il cervello i filosofi, da Aristotile a Galileo, e come tutti <lb/>rimanessero lontani dal coglier nel segno. </s>

<s>Non sentenzierebbe per&ograve; <lb/>in conformit&agrave; del vero storico colui, che volesse ancora seguitare <lb/>a dire essere stato il Newton il primo a risolvere l'astruso pro&shy;<lb/>blema col principio universale dell'attrazione. </s>

<s>Era infino dal 1624 <lb/>apparita in Roma alla luce una Dissertazione di poche pagine, che <lb/>portava in fronte il titolo di <emph type="italics"/>Euripus,<emph.end type="italics"/> e sottoscritto il nome di un <lb/>Autore, appellato dal Newton stesso ad altro proposito <emph type="italics"/>Vir celeber&shy;<lb/>rimus.<emph.end type="italics"/> Quell'Autore &egrave; Marcantonio De Dominis, Arcivescovo di Spa&shy;<lb/>latro, &egrave; quel <emph type="italics"/>certo prelato,<emph.end type="italics"/> di cui parla Galileo nella IV Giornata <lb/>de'Due Massimi Sistemi. </s>

<s>L'aver ivi taciuto il nome dell'uomo <lb/>celeberrimo, e l'aver commesso di parlarne e di darne giudizio a <lb/>Simplicio, sarebbe segno di disprezzo, se non &egrave; piuttosto una scusa <lb/>dell'esser temerariamente entrato a sentenziare di una dottrina, <lb/>senza aver letto colla debita attenzione il libro. </s>

<s>Che quel Simplicio <lb/>galileiano infatti non abbia veramente letto l'<emph type="italics"/>Euripus<emph.end type="italics"/> dello Spala&shy;<lb/>trese, par chiaro dall'apporgli un errore, che non si trova a parer <lb/>nostro in nessuna parte di quel Trattato, ed &egrave; che, la Luna abbia <lb/>potere d'attrar l'acqua marina agli antipodi, <emph type="italics"/>per aver ella possanza <lb/>di conferire una tal facolt&agrave; a quel grado del zodiaco che gli &egrave; <lb/>opposto<emph.end type="italics"/> (Alb. </s>

<s>I, 458). </s></p><p type="main">

<s>Il Newton che pure, a proposito dell'Iride celeste, citava il <lb/>Trattato <emph type="italics"/>De radiis visus et lucis<emph.end type="italics"/> senz'averlo letto, &egrave; probabilissimo <lb/>che non vedesse del nostro Autore nemmen questa <emph type="italics"/>Sentenza<emph.end type="italics"/> sul <lb/>flusso marino, ma &egrave; mirabile in ogni modo, il riscontro che &egrave; fra <lb/>le dottrine del Filosofo inglese e quelle stesse che il nostro Dalmata <lb/>professava un mezzo secolo avanti. </s>

<s>L'intumescenza e delumescenza <lb/>dell'acqua marina non &egrave; per lui, come da molti si diceva, un ef&shy;<lb/>fetto di condensazione o di rarefazione &ldquo; Sed vere fieri motu locali <lb/>aquae, eiusque a loco ad locum vera confluentia et refluentia &rdquo; <lb/>(Euripus, Romae, 1624, pag. </s>

<s>10). Il quale effetto non &egrave; dal calore <lb/>del sole, ma dalle due virt&ugrave; insieme congiunte del Sole e della <lb/>Luna, i quali due corpi celesti attraggon con varia intensit&agrave; l'acqua <lb/>marina, a quel modo che il magnete attrae a s&egrave; il ferro, e, se non <lb/>gli si congiunge con immediato contatto, par che pure lo renda <pb xlink:href="020/01/252.jpg" pagenum="233"/>pi&ugrave; leggero. </s>

<s>&ldquo; Si enim Magnes, hoc est terra quaedam crassa et <lb/>rudis, mirabili illa sua vi naturali et qualitate non occulta, sed <lb/>quoad effectum omnibus manifestissima, trahit ad se ferrum ex una <lb/>parte, ex alia vero opposita id a se propellit et amovet; cur ali&shy;<lb/>quid simile esse in coelestibus illis corporibus multo nobilioribus, <lb/>et efficacioribus negabimus? </s>

<s>&rdquo; (ibi, pag. </s>

<s>4). Da ci&ograve; ne segue che <lb/>concorrendo insieme il Sole e la Luna a produr l'effetto, bench&egrave; <lb/>questa sia assai pi&ugrave; efficace e potente di quello, l'effetto stesso <lb/>varier&agrave; al variar gli aspetti de'due astri, secondoche, cio&egrave;, la Luna <lb/>sar&agrave; in congiunzione col Sole o nell'opposizione o nelle quadrature. <lb/></s>

<s>&ldquo; Cum enim non sola Luna sed etiam Sol, pro suo modulo, suum <lb/>culmen, licet minorem efficiat, ex diversis aspectibus, qui sunt inter <lb/>solem et lunam, maior et minor fieri debet fluxus et refluxus &rdquo; <lb/>(ibi, pag. </s>

<s>59). </s></p><p type="main">

<s>Dir che il De Dominis risolva il problema, con quella sicurt&agrave; <lb/>e con quella pienezza che lo risolve il Newton, sarebbe troppo pre&shy;<lb/>tendere. </s>

<s>Lo Spalatrese attribuisce l'intumescenza marina a una <lb/>forza attrattiva, simile a quella che si vede operar nel Magnete, <lb/>ma di una tal forza non conosce la legge, e perci&ograve;, fatto certo <lb/>dall'esperienze che nel produr l'effetto la Luna &egrave; pi&ugrave; potente, non <lb/>sa veder di ci&ograve; la ragione in altro, che in una simpatia per gli <lb/>umidi maggior in lei che nel Sole. </s>

<s>&ldquo; Luna enim habet longe ma&shy;<lb/>iorem sympathiam cum humidis quam Sol &rdquo; (ibi, pag. </s>

<s>10). Questo <lb/>&egrave; senza dubbio un ridursi ai peripatetici alloggiamenti, ma &egrave; del <lb/>resto, dal nostro Autore, il flusso e riflusso marino esaminato con <lb/>tanta diligenza, e i molteplici casi dispersi ridotti con tanta potenza <lb/>di raziocinio a trovar la loro spiegazione in una causa generale e <lb/>suprema; che se si fossero degnati di leggere queste cose Galileo <lb/>e il Newton ne dovrebbero esser rimasti ammirati, e avrebbero <lb/>cos&igrave; tramandato ai posteri la memoria di un Libro, che meritava <lb/>di superar la fama di suo fratello, essendo il De Dominis proceduto <lb/>per la pi&ugrave; diritta via in investigar la causa del flusso del mare, <lb/>che non quella della vista e dell'arco baleno. </s></p><p type="main">

<s><emph type="center"/>III.<emph.end type="center"/></s></p><p type="main">

<s>L'Huyghens disegn&ograve; maestrevolmente, in brevi tratti, nel II Li&shy;<lb/>bro del suo <emph type="italics"/>Cosmoteoro<emph.end type="italics"/> i progressi storici della Meccanica celeste. </s>

<s><lb/>Plutarco, nel suo Libro <emph type="italics"/>De facie in orbe Lunae,<emph.end type="italics"/> aveva detto che <pb xlink:href="020/01/253.jpg" pagenum="234"/>la Luna riman sospesa nello spazio, per l'equilibrio della sua forza <lb/>di circolazione con quello di gravit&agrave;; dottrina che fu seguita poi <lb/>dal Borelli, e applicata al moto di tutti i satelliti, e di tutti i pia&shy;<lb/>neti. </s>

<s>Il Newton dimostr&ograve; matematicamente le leggi di que'moti, e <lb/>fece veder che i fatti osservati dal Keplero erano una conseguenza <lb/>immediata di quelle leggi. </s>

<s>Io poi, soggiunge l'Huyghens, immaginai <lb/>un ipotesi, da investigar la prima causa e i primi impulsi de'moti <lb/>planetari, per via de'vortici eterei, che son tutt'altra cosa da quelli <lb/>cartesiani. </s>

<s>Anzi, io mi maraviglio, come mai il Filosofo bretone <lb/>possa avere sciupato il suo tempo in dare assetto a quelle sue <lb/>strane finzioni &ldquo; De planetarum et mundi origine commentatio <lb/>apud Cartesium tam levibus rationibus contexta est, ut saepe mirer <lb/>tantum operae in talibus concinnandis figmentis eum impendere <lb/>potuisse &rdquo; (Op. </s>

<s>varia, Lugd. </s>

<s>1724, pag. </s>

<s>721). La grande Opera dei <lb/>Principii matematici della Filosofia Naturale dissip&ograve; quel fantastico <lb/>edifizio cartesiano, e pos&ograve; la Nuova Astronomia sopra i suoi pi&ugrave; <lb/>solidi fondamenti. </s>

<s>Tutto il mistero dei Grandissimi fu allora svelato <lb/>dal Filosofo inglese, e i posteri non hanno fatto altro che confer&shy;<lb/>mare quelle scoperte, e ampliarle nell'Astronomia fisica o nella <lb/>Uranografia, di cui il merito &egrave; dovuto principalmente a quella per&shy;<lb/>fezione, a che l'arte, meglio che la scienza, ha saputo condurre i <lb/>canocchiali. </s></p><p type="main">

<s>Ma il Newton, come da noi s'accennava di sopra, aveva prima <lb/>scoperto il mondo dei Piccolissimi, intorno a che il Cartesio e il <lb/>Gassendo eran venuti a gara delle pi&ugrave; sottili e stravaganti finzioni. </s>

<s><lb/>Cos&igrave; fatte finzioni son quelle stesse, che illudevano il grande in&shy;<lb/>gegno del Borelli, quando, per esempio, a spiegar gli effetti di <lb/>capillarit&agrave;, da lui stesso scoperti ne'corpiccioli galleggianti, im&shy;<lb/>maginava quella lanugine e que'cigli flessibili, con cui, s&ugrave; per le <lb/>asperit&agrave; de'corpi solidi attaccandosi, potessero risalir sul naturale <lb/>livello le minime particelle dell'acqua. </s>

<s>Il Newton, come fece pel <lb/>Mondo dei Grandissimi, disperse anco quest'altre filosofiche finzioni, <lb/>introducendo il principio delle forze molecolari. </s>

<s>A ci&ograve; fare egli <lb/>attese in quelle celebri Questioni, che, ridotte al numero di XXXI, <lb/>nella seconda edizione dell'Ottica, appose in fine del suo Trattato. </s>

<s><lb/>Tali Questioni, bench&egrave; possano essere facilmente sfuggite, per il <lb/>modesto luogo che fu loro assegnato e per l'umile veste, alla debita <lb/>estimazione dei dotti, hanno nulladimeno tutta l'importanza, ch'ebbe <lb/>la grande Opera de'<emph type="italics"/>Principii.<emph.end type="italics"/></s></p><p type="main">

<s>A noi piace di rassomigliare i due libri del Filosofo inglese <pb xlink:href="020/01/254.jpg" pagenum="235"/>a'due strati estremi di una profonda acqua corrente. </s>

<s>Quello dei <lb/>Principii della Filosofia, in cui le leggi del Grandissimo Mondo si <lb/>risolvono nell'unico principio delle forze centrali, rappresenta lo <lb/>strato pi&ugrave; alto, e pi&ugrave; largamente visibile della corrente; quell'altro, <lb/>che &egrave; il libro delle <emph type="italics"/>Questioni,<emph.end type="italics"/> e in cui le leggi del Piccolissimo <lb/>Mondo si risolvono nell'unico principio delle forze molecolari, rap&shy;<lb/>presenta lo strato pi&ugrave; basso, e men visibile della medesima corrente. </s>

<s><lb/>Questo strato, quasi soffrisse la compressione de'soprastanti, con&shy;<lb/>tiene in s&egrave; strettamente condensate e contratte le nuove parti di <lb/>scienza sperimentale, che si videro svolgere e fluire nel secolo XVIII. <lb/>Anzi, come gli strati intermedii delle acque correnti son rapiti e <lb/>accelerati per la comunicazione del moto de'due strati estremi; <lb/>cos&igrave; da que'due strati estremi de'Principii neutoniani e delle Que&shy;<lb/>stioni, in mezzo a cui corre, vien rapita e accelerata, in questo <lb/>nuovo tratto de'suoi progressi, la larga e alto sonante fiumana della <lb/>Scienza. </s></p><p type="main">

<s>Gran parte della scienza sperimentale, che si volge e corre giu <lb/>per questa fiumana, &egrave;, per la nobilt&agrave; sua propria e per l'impor&shy;<lb/>tanza e l'utilit&agrave; delle applicazioni, l'Idraulica. </s>

<s>Il potente impulso, <lb/>che ella ricevette nella scuola galileiana per opera del Guglielmini, <lb/>era per se sufficiente a promuoverla ne'suoi progressi, senz'altri <lb/>estrinseci aiuti; nonostante risent&igrave; anch'essa i benefici influssi delle <lb/>dottrine neutoniane, influssi, che si posson rassomigliare a quel&shy;<lb/>l'aura di vento, che, secondando il moto della corrente, giova a <lb/>velocitare la piena di un fiume. </s></p><p type="main">

<s>Giovan Domenico Guglielmini, gi&agrave; l'abbiamo accennato, ap&shy;<lb/>partiene alla scuola galileiana, nella quale fu allevato dal Montanari, <lb/>discepolo del Borelli. </s>

<s>Egli aveva gi&agrave;, il Guglielmini, in sul finir del <lb/>secolo XVII, diffuso in Bologna il suo magistero ne'varii ordini <lb/>delle scienze sperimentali, quand'ancora il sole della nuova Filo&shy;<lb/>sofia inglese non era apparito sul nostro orizzonte. </s>

<s>Il Guglielmini <lb/>perci&ograve; appartiene al periodo storico precedente, e in quella parte <lb/>del Dramma si svolge la sua azione, ond'&egrave; che tutt'altro che ricever <lb/>beneficio all'ingegno dalle nuove dottrine neutoniane, &egrave; ragionevole <lb/>pensar che il Newton stesso s'ispirasse in parte alle speculazioni di <lb/>lui, e se ne giovasse nelle aggiunte alle succissive impressioni dei <lb/>suoi libri. </s>

<s>Senz'ammetter ci&ograve;, non si potrebbero attribuire ad altro <lb/>che al caso que'mirabili riscontri, che si notano fra certe idee <lb/>espresse negli opuscoli minori del nostro Filosofo di Bologna, e <lb/>certe altre idee simili, che balenano qua e l&agrave; per le Questioni del <pb xlink:href="020/01/255.jpg" pagenum="236"/>Filosofo di Cambridge. </s>

<s>Alcuni di que'riscontri ci occorreranno a <lb/>notare in questo stesso Discorso, ma giova intanto intrattenerci <lb/>brevemente sopra quegli argomenti, da cui si conclude che, in <lb/>Idrometria, le speculazioni del Newton prendevano probabilmente <lb/>l'indirizzo da quelle del Guglielmini. </s></p><p type="main">

<s>Fra i Principii matematici della Filosofia Naturale non pote&shy;<lb/>vano non trovar luogo quelli concernenti le leggi del moto, con cui <lb/>l'acque fluiscono dai fori aperti ne'vasi. </s>

<s>La proposizione XXXVII <lb/>infatti del secondo Libro di que'Principii, conforme alla prima <lb/>edizione che fu fatta nel 1686, ha per soggetto il problema degli <lb/>efflussi, che dall'Autor si risolve pi&ugrave; coi calcoli arguti, che coll'ap&shy;<lb/>plicarvi le leggi del moto dei gravi. </s>

<s>Nella successiva edizione, che <lb/>&egrave; del 1713, l'Autore introduce, in questa parte del suo Libro, una <lb/>notabilissima riforma. </s>

<s>La proposizione de'flussi, ricorre in ordine <lb/>al numero XXXVI, e vi si professa espressamente il principio, che <lb/>le velocit&agrave; de'liquidi nel fluire da'fori de'vasi, son proporzionali <lb/>alle radici delle altezze. </s>

<s>Cos&igrave; fatto principio &egrave; concluso da'teoremi <lb/>galileiani della caduta de'gravi, riscontrati di fatto ne'pi&ugrave; squisiti <lb/>esperimenti. </s>

<s>Da'teoremi sui proietti conclude il Newton che gli <lb/>zampilli obliqui descrivono tutti una parabola, il parametro della <lb/>quale varia secondo la varia distanza che passa, tra la superficie <lb/>del liquido, e il centro dell'apertura del vaso. </s>

<s>Misurati diligente&shy;<lb/>mente questi parametri e attendendo agli effetti della resistenza <lb/>dell'aria e della contrazion della vena, trovava che gli zampilli <lb/>parabolici rispondevan prossimamente alle traiettorie che sarebbero <lb/>state descritte da un grave gettato con quell'impeto, che avrebbe <lb/>conceputo nel cadere da tanta altezza, quanta &egrave; quella del liquido <lb/>sul centro del foro, da cui fluisce. </s>

<s>Questo, che fu tentato anche dai <lb/>nostri Accademici del Cimento, &egrave; senza dubbio il pi&ugrave; diretto, ma <lb/>il pi&ugrave; difficile modo d'eseguir l'esperienza: difficolt&agrave;, che dalla sola <lb/>raffinatissima arte del Newton sarebbesi potuta superare. </s></p><p type="main">

<s>Insistendo sempre sull'applicazione de'teoremi galileiani, il <lb/>nostro Autore conclude teoricamente, a modo del Torricelli, e spe&shy;<lb/>rimentalmente conferma che gli zampilli verticali risalgono s&ugrave; con <lb/>l'impeto stesso dovuto alla caduta, e soggiunge appresso che la <lb/>quantit&agrave; del moto si dee misurar dal prodotto della sezione del <lb/>foro, per il doppio della colonna e non per la semplice colonna del <lb/>liquido sopraincombente. </s>

<s>Le controversie insorte in tal proposito <lb/>fra il Jurin e il Michelotti, son notabili nella storia, ma pure il <lb/>Newton, professando quel principio, non faceva altro pi&ugrave; che appli-<pb xlink:href="020/01/256.jpg" pagenum="237"/>care al moto de'fluidi il primo de'Teoremi dimostrati, nel III Dia&shy;<lb/>logo, da Galileo, dovendo l'acqua, in conformit&agrave; di questo teorema, <lb/>passar con moto equabile un doppio spazio di quello che ha pas&shy;<lb/>sato in cader dalla superficie e scender fino a fluire dall'apertura <lb/>del vaso. </s>

<s>E bench&egrave; i nostri Accademici fiorentini, come si par dai <lb/>loro Manoscritti, avessero gi&agrave; fatte osservazioni e sperimenti in pro&shy;<lb/>posito, nonostante &egrave; il primo il Newton a descrivere, in quella stessa <lb/>Proposizione citata, il contrarsi della vena all'esito, e il formarsi <lb/>della <emph type="italics"/>cateratta<emph.end type="italics"/> alla superficie del liquido. </s>

<s>In occasione di questa <lb/>cateratta, osserva Eustachio Manfredi, nella Annotazione alla pro&shy;<lb/>posizione VI del I Libro della <emph type="italics"/>Natura dei fiumi,<emph.end type="italics"/> che il Guglielmini <lb/>l'aveva gi&agrave; descritta e matematicamente considerata, nel IV e V Li&shy;<lb/>bro della sua <emph type="italics"/>Misura delle acque correnti.<emph.end type="italics"/> Esamineremo a suo luogo <lb/>cos&igrave; fatta osservazione del Manfredi, ma intanto, ripensando a ci&ograve; <lb/>che potesse aver dato occasione al Newton di ritornare ai prin&shy;<lb/>cipii idrometrici professati dagl'Italiani, ci occorre alla memoria il <lb/>Trattato della Misura delle Acque correnti, citato ora dallo stesso <lb/>Manfredi. </s></p><p type="main">

<s>Il d&igrave; 19 Novembre 1690, Antonio Magliabechi, celebre biblio&shy;<lb/>tecario in Firenze, annunziava al Granduca d'aver da qualche giorno <lb/>ricevuto, dal signor Guglielmini, un libro intitolato <emph type="italics"/>Aquarum fluen&shy;<lb/>tium mensura nova methodo inquisita<emph.end type="italics"/> stampato a Bologna (MSS. <lb/>Gal. </s>

<s>Cim. </s>

<s>T. XXI, c. </s>

<s>16), e il 27 Ottobre 1691, lo stesso Magliabechi <lb/>annunziava d'aver ricevuto l'altra parte del libro (ivi, c. </s>

<s>18). Ci&shy;<lb/>tiamo questi documenti bibliografici, per dir che la prima parte, <lb/>ossia i primi tre libri della Misura delle Acque correnti furono <lb/>pubblicati nel 1690, e gli altri tre l'anno dopo. </s>

<s>L'Autore di quel&shy;<lb/>l'Opera si assumeva un difficile incarico, qual'era quello di decider <lb/>se la velocit&agrave; delle acque correnti seguiva la legge ammessa dal <lb/>Castelli e confermata dalla grande autorit&agrave; del Cassini, o seguiva <lb/>l'altra dimostrata dal Torricelli, e confermata in tanti modi poi dal <lb/>Viviani. </s>

<s>Il Guglielmini s'affid&ograve; a quella maniera di sperimenti, che <lb/>sembrano men soggetti ad errori di tutti gli altri, e de'quali il <lb/>Magiotti per il primo aveva dato gli esempii. </s>

<s>Perci&ograve;, dalla quantit&agrave; <lb/>dell'acqua raccolta, in determinati tempi, dal flusso di un vaso, <lb/>concludeva le sue esperienze riscontrar colla legge professata dal <lb/>Torricelli. </s>

<s>Il Guglielmini veniva altres&igrave;, con questo libro, a intro&shy;<lb/>durre nell'ldrometria le <emph type="italics"/>velocit&agrave; medie,<emph.end type="italics"/> senza l'uso delle quali ri&shy;<lb/>manevano incerte tutte le proposizioni dimostrate prima di lui dal <lb/>Castelli. </s></p><pb xlink:href="020/01/257.jpg" pagenum="238"/><p type="main">

<s>Dietro ci&ograve;, par probabile anche a noi ci&ograve; che accennavasi dal <lb/>Manfredi, ed &egrave; che il Newton, dal 1686 al 1713, nel quale spazio <lb/>di tempo si divulg&ograve; l'Opera del Guglielmini, potesse aver riformate <lb/>le sue idee, intorno alla legge della velocit&agrave; delle acque correnti, <lb/>e potesse anche aver preso occasione di rivolgersi a considerare la <lb/>cateratta, da ci&ograve; che ne trov&ograve; scritto dall'Autore, nell'Opera stessa <lb/><emph type="italics"/>Aquarum fluentium Mensura.<emph.end type="italics"/></s></p><p type="main">

<s>Con questa, e con le <emph type="italics"/>Lettere idrostatiche<emph.end type="italics"/> contro il Papin, nelle <lb/>quali si dimostra ad evidenza in che modo, per la pressione am&shy;<lb/>mosferica, s'alterino le leggi del moto dell'Acque, ne'tubi chiusi, il <lb/>Guglielmini si preparava a dar mano all'altra insigne opera <emph type="italics"/>Della <lb/>Natura de'fiumi,<emph.end type="italics"/> in cui, riducendo a un unico principio lo stabi&shy;<lb/>lirsi degli alvei, parve non meritar lode minore del Newton, che <lb/>a un principio unico aveva pure ridotto lo stabilirsi, nella regolare <lb/>perpetuit&agrave; degli orbi, i moti di tutti i pianeti. </s></p><p type="main">

<s>Cos&igrave;, l'Idraulica, indipendentemente da qualunque insegna&shy;<lb/>mento straniero, si serb&ograve; schiettamente italiana, ma, promossa dai <lb/>discepoli e dai seguaci del Guglielmini, sent&igrave; pure, nel secolo XVIII, <lb/>qualche benefico influsso dai nuovi metodi e dalle nuove dottrine <lb/>neutoniane. </s>

<s>Uno dei principali fra questi benefizii fu quello del per&shy;<lb/>suadersi che fecero gli Idraulici italiani essere una reale tegnenza <lb/>fra le minime particelle dell'acqua; tegnenza che, con pi&ugrave; grave <lb/>danno di quel che non si crederebbe, Galileo le avea negata. </s>

<s>Il <lb/>Guglielmini rimedi&ograve; felicemente al danno, proseguendo gli inse&shy;<lb/>gnamenti del maestro suo Geminiano Montanari, che avrebbe potuto <lb/>arricchire la scienza di un nuovo e impertantissimo Trattato sulla <lb/><emph type="italics"/>Natura dei fluidi,<emph.end type="italics"/> se non l'avesse il Senato distratto in costruir <lb/>nuovi mulini, da arricchire il pubblico erario e i mercanti di seta <lb/>bolognesi (MSS. Gal. </s>

<s>Disc. </s>

<s>T. CXLV, c. </s>

<s>230). Nonostante, nella pri&shy;<lb/>vata Accademia dell'Ab. </s>

<s>Sampieri, ei fu il primo a richiamar l'at&shy;<lb/>tenzione de'fisici, non sulla sola viscosit&agrave; dell'acqua, ma sulle pro&shy;<lb/>porzioni che questa ha colla viscosit&agrave; degli altri liquidi. </s>

<s>Le nuove <lb/>ricerche sperimentali ebbero occasione dall'avere osservato <emph type="italics"/>che li <lb/>corpi gravi discendono pi&ugrave; velocemente per l'acqua comune, che <lb/>per l'acquavite e per l'olio<emph.end type="italics"/> (MSS. Gal. </s>

<s>Cim. </s>

<s>T. XIX, c. </s>

<s>69) ci&ograve; che <lb/>fu sospettato dipendere dalla viscosit&agrave; maggiore in questi due li&shy;<lb/>quidi e in altri simili, che no nell'acqua. </s></p><p type="main">

<s>A queste esperienze, fatte nel 1667, non sar&agrave; stato presente il <lb/>Guglielmini, che aveva allora dodici anni, ma le avr&agrave; apprese in <lb/>seguito dal Maestro, per applicarle, come poi fece, a spiegar la <pb xlink:href="020/01/258.jpg" pagenum="239"/>natura e gli effetti del filone nella corrente, non che a mostrar <lb/>l'efficacia, che gli strati superiori di essa hanno in promuovere le <lb/>velocit&agrave; degli strati inferiori. </s>

<s>Nonostante, il principio della viscosit&agrave; <lb/>dell'acqua ammesso dal Guglielmini, e applicato alla Natura dei <lb/>fiumi, non aveva altro valor che di un ipotesi, appoggiata ai fatti <lb/>osservati nella sperimentale Accademia bolognese; fatti, e il Mon&shy;<lb/>tanari stesso non lo nega, che potevano anche dipendere da tutt'altra <lb/>cagione. </s></p><p type="main">

<s>Come ipotesi, perci&ograve;, quella della viscosit&agrave; dell'acqua fu nuo&shy;<lb/>vamente cacciata via dalla scienza, per la grande autorit&agrave; di uno <lb/>scrittore, che succede in tempo e in dignit&agrave; al Guglielmini, il p. </s>

<s>abate <lb/>Guido Grandi, il quale, troppo matematico e troppo ossequioso a <lb/>Galileo, ne illustra, nel suo Trattato del <emph type="italics"/>Movimento dell'acque,<emph.end type="italics"/> le <lb/>dottrine, e ne commenta insieme gli errori. </s>

<s>Cacciare un errore in&shy;<lb/>trodotto nella scienza da una tanta autorit&agrave;, qual'era quella di Ga&shy;<lb/>lileo, non sembrava possibile che a un'altra autorit&agrave; di pari grado, <lb/>e tale era appunto quella del Newton, dalla nuova filosofia del quale <lb/>si concludeva la viscosit&agrave; dell'acqua e di tutti gli altri liquidi, <lb/>com'un effetto naturalissimo dell'attrazione molecolare. </s>

<s>Cosi l'ipo&shy;<lb/>tesi del Montanari, seguita dal Guglielmini, torn&ograve; in quasi certezza <lb/>di matematica conclusione e Paolo Frisi, uno de'pi&ugrave; illustri seguaci <lb/>dello stesso Guglielmini, fu primo a risentire questi benefici effetti <lb/>della Filosofia neutoniana, applicando il principio della viscosit&agrave; <lb/>dell'acqua a spiegar quel particolar fatto dell'accelerarsi della cor&shy;<lb/>rente, che si design&ograve; col nome di <emph type="italics"/>chiamata allo sbocco,<emph.end type="italics"/> e intro&shy;<lb/>ducendo quello stesso principio nel general modo di regolare i <lb/>Fiumi e i torrenti, di che arricch&igrave; la scienza di un Trattato diviso <lb/>in tre libri. </s></p><p type="main">

<s>Questo, d'aver per sempre sconfitto un errore, che cacciato la <lb/>prima volta minacciava, coll'autorit&agrave; di Galileo, di tornare a in&shy;<lb/>vadere dannosamente la scienza, fu uno de'principali, ma non il <lb/>solo de'benefizii, che venisse all'Idraulica dalla Filosofia neutoniana. </s>

<s><lb/>Altro rilevantissimo benefizio provenne dagli impulsi efficaci e dai <lb/>luminosi esempi, che dava il Newton a trattar de'moti delle acque <lb/>correnti co'metodi analitici, e col buon uso di comporre e di risolver <lb/>le forze. </s>

<s>Il Guglielmini, n&egrave; nel Trattato Della Misura delle acque <lb/>correnti, n&egrave; in quell'altro Della Natura de'fiumi, non s'era dilun&shy;<lb/>gato un passo dagli antichi metodi galileiani, e occorrendogli di <lb/>dover assegnar la direzione e misurar la quantit&agrave; di forza risultante <lb/>dal comporsi insieme due correnti, una delle quali confluisce con <pb xlink:href="020/01/259.jpg" pagenum="240"/>l'altra, incespica e s'avvolge ne'paralogismi stessi del Maestro suo <lb/>Montanari, a cui, in determinar la natura e il moto della Corrente <lb/>adriatica e delle correnti marine in generale, tanto nocquero quei <lb/>meccanici paralogismi. </s></p><p type="main">

<s>Primo a lasciar le vie vecchie, per seguitare le nuove, in trattar <lb/>del moto dell'acque, fu Bernardino Zendrini, che in comporre il <lb/>suo Trattato, a cui di&egrave; il titolo di <emph type="italics"/>Leggi e fenomeni, regolazioni ed <lb/>usi delle acque correnti,<emph.end type="italics"/> dava opera nel 1739 (Firenze 1770, pag. </s>

<s>49). <lb/>Chi legge la Prefazione al libro, s'accorge tosto che l'Autore intro&shy;<lb/>duceva, col metodo analitico, una novit&agrave; nella scienza italiana, e <lb/>perci&ograve; intrattien, fin da principio, i lettori, studiandosi di persua&shy;<lb/>derli ad accogliere una tal novit&agrave;, e a voler fare la giusta stima <lb/>de'vantaggi di lei. </s>

<s>Fu pure il Zendrini stesso de'primi, che, fattosi <lb/>oramai seguace de'nuovi metodi neutoniani, mostrasse il retto uso <lb/>che doveva farsi della composizione e risoluzion delle forze, colla <lb/>regola del parallelogrammo. </s>

<s>Vero &egrave; che di ci&ograve; i primi esempi erano <lb/>stati dati dal Grandi, ma fu il nostro Matematico della Serenissima <lb/>Repubblica di Venezia che, richiamandosi giusto a una proposizione <lb/>dimostrata dallo stesso Grandi, not&ograve;, il primo, un gravissimo errore, <lb/>sfuggito a tutti i censori, in che era incorso il Michelini; errore, <lb/>che consisteva nello scambiar con una delle componenti la resul&shy;<lb/>tante di quella forza, con che le acque scavano il fondo dei fiumi. </s></p><p type="main">

<s>Noi riconosciamo anche questo per uno di quei gran benefizi <lb/>derivati alla scienza italiana, nel secolo XVIII, dagli esempi dei <lb/>metodi neutoniani, non solamente, perch&egrave; la prima edizione dei <lb/>Principii matematici di Natural Filosofia preced&egrave; di un anno il <lb/>progetto della <emph type="italics"/>Nouvelle mechanique<emph.end type="italics"/> del Varignon, pubblicata po&shy;<lb/>stuma nel 1725, ma, perch&egrave;, com'ad altro proposito si diceva pi&ugrave; <lb/>sopra, a sradicar dalle menti degli Italiani l'opinion che fosse falso <lb/>il teorema dell'Herigonio, opinione invalsa e confermata da due <lb/>grandi autorit&agrave; quali eran quelle di Galileo e del Borelli; ci voleva <lb/>un'altra autorit&agrave;, che non fosse punto minore, l'autorit&agrave; insomma <lb/>d'Isacco Newton. </s></p><p type="main">

<s><emph type="center"/>IV.<emph.end type="center"/></s></p><p type="main">

<s>Che i metodi della nuova Filosofia neutoniana si riscontrino <lb/>con quegli stessi di Galileo, e che da un tale felicissimo incontro <lb/>ne sien conseguiti i progressi, che fecero le scienze sperimentali <pb xlink:href="020/01/260.jpg" pagenum="241"/>nel secolo XVIII, i lettori ne saranno meglio persuasi dalla verit&agrave; <lb/>delle cose, che dai nostri discorsi. </s>

<s>Giova nonostante osservare che, <lb/>mentre Galileo col suo Platone instituisce la sua Filosofia naturale <lb/>nella regolarit&agrave; geometrica delle forme, ch'ei serenamente contem&shy;<lb/>pla, senza troppo pensare al concorso delle cause, che le hanno <lb/>prodotte; il Newton soggiunge, nella sua Nuova Filosofia, l'opera <lb/>concorrente di quelle cause, che egli riconosce nella gran dualit&agrave; <lb/>delle forze di attrazione e di repulsione. </s>

<s>Di qui &egrave; che il metodo <lb/>neutoniano, bench&egrave; non differisca sostanzialmente da quello di Ga&shy;<lb/>lileo, &egrave; cos&igrave; concluso in una formula nuova: &ldquo; In mathesi investi&shy;<lb/>gandae sunt virium quantitates, et rationes illae, quae ex conditio&shy;<lb/>nibus quibuscumque positis consequentur: deinde, ubi in physicam <lb/>descenditur, conferendae sunt hae rationes cum phaenomenis, ut <lb/>innotescat quaenam virium conditiones singulis corporum attracti&shy;<lb/>vorum generibus competant &rdquo; (Princip. </s>

<s>Lib. </s>

<s>I. </s>

<s>Coloniae 1760, pa&shy;<lb/>gina 464). </s></p><p type="main">

<s>La scienza fisica dunque si riduce, pel Newton, a conoscer la <lb/>natura e l'intensit&agrave; delle forze, non che le condizioni del loro vario <lb/>operare. </s>

<s>E perch&egrave; da queste forze &egrave; commossa ogni minima par&shy;<lb/>ticella componente de'corpi, si vede di qui aprirsi altri campi a <lb/>una fisica nuova, la quale fu detta molecolare, ma che si potrebbe <lb/>pi&ugrave; volgarmente chiamar col nome di fisica sottile. </s>

<s>La legge da <lb/>noi, nella prima Parte di questo Discorso formulata, che l'intelli&shy;<lb/>gibilit&agrave; della forma precede l'intelligibilit&agrave; della materia, e l'in&shy;<lb/>telligibilit&agrave; della materia crassa precede l'intelligibilit&agrave; della ma&shy;<lb/>teria via via pi&ugrave; sottile; qui si vede avverarsi esattamente, essendo <lb/>quelle due nuove parti della Fisica sottile, che si conoscono sotto il <lb/>nome di Elettricismo, e sotto l'altro pi&ugrave; esteso di Chimica, non <lb/>prima venute alla luce, che nel secolo XVIII, come parto e portato <lb/>della nuova Filosofia neutoniana. </s></p><p type="main">

<s>Dappoi che Ottone di Guericke dimostr&ograve;, nel Cap. </s>

<s>XV del <lb/>quarto Libro de'suoi Esperimenti magdeburgici, come tutte le virt&ugrave; <lb/>della materia universale sien rappresentate da una sfera di zolfo, <lb/>confricata colle mani, mentre che celerissimamente &egrave; girata attorno; <lb/>e come quella stessa sfera dia evidenti segni della virt&ugrave; calorifica <lb/>e della lucente; invalse l'opinione che sieno le sostanze sulfuree <lb/>primo e principale elemento del calore e della luce. </s>

<s>Il Guglielmini <lb/>se ne giov&ograve; per cacciar dalla Fisiologia l'errore della <emph type="italics"/>fiamma vi&shy;<lb/>tale,<emph.end type="italics"/> asserendo esser causa del calore negli animali l'agitazione <lb/>delle sostanze sulfuree contenute nel sangue. </s>

<s>Tutti i fenomeni elet-<pb xlink:href="020/01/261.jpg" pagenum="242"/>trici e fosforici, non eccettuati i baleni e le folgori, eran ridotti a <lb/>esalazioni sulfuree, disperse per l'aria e per le sostanze dei corpi. </s>

<s><lb/>N&egrave; da queste stesse idee si dilunga il Newton nell'VIII delle sue <lb/>Questioni. </s></p><p type="main">

<s>S'era intanto osservato che la virt&ugrave; di attrarre i minimi cor&shy;<lb/>piccioli e d'investirli di luce, non era propria a soli i globi di zolfo, <lb/>ma conveniva altres&igrave;, e forse meglio, ai globi o ai cilindri di vetro, <lb/>celermente girati e confricati allo stesso modo. </s>

<s>Cos&igrave;, il globo me&shy;<lb/>tafisico del Guericke dette occasione a costruir le prime macchine, <lb/>per via delle quali, dice il Newton stesso, nella citata Questione: <lb/>&ldquo; vapor electricus, frictione manus e vitro excitatus, et ad cartam <lb/>albam, linteum vel digitum allisus, ita agitabitur, ut lucem continuo <lb/>emittat. </s>

<s>&rdquo; Questo vapore elettrico fu largo e glorioso soggetto al <lb/>Franklin, al Symmer al Nollet d'esperienze e di teorie, ma di cos&igrave; <lb/>fatte teorie quelle che pi&ugrave; giovassero alla scienza, e che furon pi&ugrave; <lb/>tenute in onore, si debbono ai due grandi elettricisti italiani, a <lb/>Giovan Batista Beccaria di Mondov&igrave;, e al comasco Alessandro Volta, <lb/>l'ingegno de'quali il Newton fecond&ograve; con gli spiriti della sua Nuova <lb/>Filosofia. </s></p><p type="main">

<s>Che siano le speculazioni del Fisico monregalese veramente <lb/>avvivate da quelli spiriti, se ne avvede presto ogni lettore che svolge <lb/>i due Libri <emph type="italics"/>Dell'elettricismo artificiale e naturale,<emph.end type="italics"/> avendo quelle <lb/>stesse speculazioni ivi esposte, trovato nell'Autore conforto e scusa <lb/>da una sentenza ch'ei cita dalla XXXI Questione neutoniana (Del&shy;<lb/>l'elettric. </s>

<s>Torino 1753, pag. </s>

<s>40). N&egrave; solo il metodo attinge il Nostro <lb/>a quelle filosofiche fonti, ma il principio altres&igrave;, che informa le sue <lb/>nuove dottrine: principio ch'ei sagacemente ritrova nella parola <lb/>stessa di <emph type="italics"/>vapore,<emph.end type="italics"/> con cui il Newton qualifica la natura propria della <lb/>sostanza elettrica &ldquo; Chiamo, egli dice, vapore elettrico, il fluido che <lb/>ne'corpi elettrizzati seintilla, fa sentire il venticello elettrico, forma <lb/>il fiocco elettrico, e la stelletta elettrica, ritenendo il nome datoli <lb/>da Newton lib. </s>

<s>III Ottica, questione VIII &rdquo; (ivi, pag. </s>

<s>10). Dall'avere <lb/>infatti l'elettricit&agrave; natura di vapore conclude il Beccaria l'esistenza <lb/>e il modo di quell'elettricismo <emph type="italics"/>effluente<emph.end type="italics"/> e di quell'altro elettricismo <lb/><emph type="italics"/>affluente,<emph.end type="italics"/> ambedue costituiti di materie somigliantissime, che egli <lb/>sostituisce all'elettricit&agrave; vitrea e resinosa del Symmer, e all'elet&shy;<lb/>tricit&agrave; positiva e negativa del Franklin. </s></p><p type="main">

<s>Dal riguardar la materia elettrica sotto l'aspetto neutoniano, <lb/>conclude il Nostro una legge unica e universalissima, ci&ograve; che nes&shy;<lb/>suno aveva tentato prima di lui, dalla quale dipende e si regola <pb xlink:href="020/01/262.jpg" pagenum="243"/>una variet&agrave; complicatissima di effetti. </s>

<s>L'applicazione di quella legge <lb/>non fu sempre trovata sufficiente, e talvolta fu scoperta anco fal&shy;<lb/>lace, ma pur conduce spesso l'Autore a incontrarsi in concetti, <lb/>che un secolo e pi&ugrave; dopo, ad alcuni scrittori di elettricit&agrave;, parvero <lb/>nuovi. </s>

<s>Di tali concetti si potrebbe, per esempio, citar quello del <lb/>riconoscer la causa del pi&ugrave; violento irrompere della scarica in quel <lb/>punto, in cui pi&ugrave; si ristringe un cilindro conduttore, nella legge <lb/>di tutti i fluidi in moto applicata alla elettricit&agrave;, che cio&egrave; le velocit&agrave; <lb/>stanno in ragion reciproca delle sezioni, e perci&ograve;, dove la sezione <lb/>&egrave; minima, come nelle punte, ivi il vapore elettrico acquista impeto <lb/>da vincer la resistenza che gli fa l'aria attraversata (ivi, pag. </s>

<s>57). </s></p><p type="main">

<s>Ma il Volta sente penetrarsi anco pi&ugrave; addentro gli spiriti della <lb/>Filosofia neutoniana. </s>

<s>I nuovi scritti sull'<emph type="italics"/>Elettricit&agrave; vindice<emph.end type="italics"/> e sopra <lb/>le <emph type="italics"/>Ammosfere elettriche,<emph.end type="italics"/> pubblicati in seguito alla citata Opera del <lb/>Beccaria, fanno pensare al giovane Fisico di Como che tutto si pu&ograve; <lb/>ridurre a una legge semplicissima, qual'&egrave; quella dell'attrazione, <lb/>intorno a che scriveva un Epistola diretta allo stesso Beccaria col <lb/>titolo: <emph type="italics"/>De vi attractiva ignis electrici.<emph.end type="italics"/> Lo splendido pensiero lo <lb/>aveva, infin dal 1763, comunicato al Nollet, il qual gli rispose pa&shy;<lb/>rergli difficilissimo il poter ridurre i fenomeni elettrici a consentir <lb/>colle leggi dell'attrazion neutoniana. </s>

<s>Ma il Volta soggiunge ch'ei <lb/>non intendeva insistere su quella attrazione universale &ldquo; quae est <lb/>massae proportionalis, et decrescit in ratione duplicata distantiarum, <lb/>qua nimirum et corpora adducuntur in centrum et Planetae in <lb/>eorum orbitis continentur &rdquo; (Opere, Firenze 1816, T. I. p. </s>

<s>6). Oltre <lb/>di questa, soggiunge, vi &egrave; un altro genere di attrazione, che inter&shy;<lb/>cede fra le minime particelle de'corpi, e da cui hanno origine <lb/>effetti particolari. </s>

<s>Sono indizio manifesto e argomento certo di cos&igrave; <lb/>fatto genere di attrazione, le riflessioni e le rifrazioni della luce, <lb/>con tutte le varie specie di fenomeni capillari &ldquo; quod quidem vel <lb/>in sola postrema Quaestione Opticae Newtoni abunde patet &rdquo; (ibi, <lb/>pag. </s>

<s>7). Cosi, viene a concluder che, non ammettendo queste forze <lb/>attrattive, &egrave; impossibile trovare in altro principio la ragion de'pi&ugrave; <lb/>ovvii e principali effetti dell'elettricit&agrave; sulla varia natura dei corpi. </s></p><p type="main">

<s>Il Volta stesso, nel passo ora citato, a provar l'esistenza e il <lb/>fatto dell'attrazione molecolare, adduceva fra gli altri argomenti <lb/>anche quello delle chimiche operazioni &ldquo; cuius nulla est pars, egli <lb/>dice, in qua praeter inertiam massae et specificam gravitatem, alia <lb/>virium mutuarum genera, non ubique se prodant et, vel invitis, <lb/>incurrant in oculos. </s>

<s>&rdquo; Chi pu&ograve; negare infatti che la Chimica, quella <pb xlink:href="020/01/263.jpg" pagenum="244"/>che con tal proprio nome si vide nel secolo passato acquistare essere <lb/>e dignit&agrave; di scienza, non sia venuta a un tal essere e a una tal <lb/>dignit&agrave;, dappoich&egrave; il Newton scoperse e dimostr&ograve; le attrazioni e le <lb/>repulsioni molecolari? </s>

<s>Le chimiche affinit&agrave;, che presiedono alla <lb/>composizione de'corpi sono effetti di quelle attrazioni: l'elasticit&agrave; <lb/>delle materie aerose, in che si decompongono i corpi sono effetto <lb/>di quelle repulsioni: d'onde &egrave; che, nelle scoperte neutoniane, trovan <lb/>loro principio e ragione, sien per sintesi o per analisi, tutte quante <lb/>le chimiche operazioni. </s></p><p type="main">

<s>La pi&ugrave; gloriosa et&agrave; per la Chimica, incomincia, senza dubbio, <lb/>dalla scoperta dell'ossigeno, nella quale si dice, ed &egrave; vero, che <lb/>non ebbero parte i nostri Italiani, bench&egrave; se la sentisse presente <lb/>Gianfrancesco Cigna, quando volle prima sperimentar sul fatto del&shy;<lb/>l'estinguersi le fiamme e del morir gli animali nell'aria chiusa. </s>

<s><lb/>Era nulladimeno italiano di Savoia quel Claudio Luigi Berthollet, <lb/>che tanta parte ebbe in istituir la nuova nomenclatura, e che di&shy;<lb/>mostr&ograve; al Lavoisier e agli altri Accademici francesi come troppo <lb/>affrettatamente era stato imposto il nome di <emph type="italics"/>ossigeno<emph.end type="italics"/> all'antico <lb/><emph type="italics"/>flogisto,<emph.end type="italics"/> essendo che anco l'idrogeno pu&ograve; acidificare una base, co&shy;<lb/>me fece veder per l'esempio del gas acido solfidrico. </s>

<s>Fu pure il <lb/>Berthollet che scoperse i varii modi tenuti dall'ossigeno in com&shy;<lb/>binarsi a una medesima base, a compor con essa acidi di diversa <lb/>natura, facendo veder che l'acido solforoso non &egrave; altro che lo stesso <lb/>acido solforico con un equivalente di ossigeno di meno. </s>

<s>Ma perch&egrave; <lb/>i grandi meriti del Berthollet son troppo pi&ugrave; noti ai francesi che <lb/>a noi, domandiamo quali furono i principii filosofici seguiti dal <lb/>nostro Autore? </s>

<s>e si risponde che furon quelli dell'attrazion mole&shy;<lb/>colare, i quali ei contrappose alle sterili teorie del Bergmann, ond'&egrave; <lb/>che fu, il Berthollet stesso, appellato col nome di Newton della <lb/>Chimica. </s></p><p type="main">

<s>Pi&ugrave; gloriosa et&agrave; di quella della scoperta dell'ossigeno, ricorse <lb/>per&ograve; alla Chimica, quand'ella strinse coll'Elettricit&agrave; quel nuovo <lb/>connubio, della fecondit&agrave; del quale v&agrave; la scienza in tutto debitrice <lb/>all'Italia. </s>

<s>Come poi il fatto avesse le sue prime e pi&ugrave; remote inspi&shy;<lb/>razioni dalla Filosofia neutoniana, si raccoglie dal ripensare a ci&ograve;, <lb/>che prima inspir&ograve; e dette occasione alla grande scoperta dell'Elet&shy;<lb/>tricit&agrave; dinamica. </s></p><p type="main">

<s>Il Beccaria, nella sua Opera sopra citata <emph type="italics"/>Dell'Elettricismo,<emph.end type="italics"/> ri&shy;<lb/>serba il Cap. </s>

<s>VII del primo Libro a trattar dell'elettricismo stesso, <lb/>per rispetto ai vegetabili, agli animali e ai metalli. </s>

<s>E studiandosi <pb xlink:href="020/01/264.jpg" pagenum="245"/>d'avvalorare le sue proprie speculazioni coll'autorit&agrave; dei placiti <lb/>neutoniani, cita varii passi qua e l&agrave; dalle varie <emph type="italics"/>Questioni,<emph.end type="italics"/> tradu&shy;<lb/>cendo, dalla XXIV, fra gli altri, il passo seguente: &ldquo; Il moto ani&shy;<lb/>male non farebbesi esso dalle vibrazioni del suddetto mezzo (etereo) <lb/>che si eccitino pella potest&agrave; del volere, e indi si propaghino affine <lb/>di accorciarsi e dilatarsi ne'muscoli, per li solidi, pellucidi, ed uni&shy;<lb/>formi capilllamenti de'nervi? </s>

<s>&rdquo; Dopo il qual passo il Beccaria im&shy;<lb/>mediatamente soggiunge: &ldquo; Le ulteriori esperienze e scoperte fatte <lb/>nell'elettricismo, di che Newton non ha visto che il principio, pare <lb/>che aggiungano forza a'dubbi del gran filosofo. </s>

<s>La velocit&agrave; con che <lb/>si muove, cambia direzione, s'arresta e di nuovo si slancia l'elet&shy;<lb/>trico vapore, pare che possano sodisfare alla velocit&agrave; e cambiamento <lb/>delle sensazioni e movimenti animali &rdquo; (ediz. </s>

<s>cit. </s>

<s>pag. </s>

<s>126). Queste <lb/>parole, scritte da chi era reputato solenne maestro nelle elettriche <lb/>dottrine, ebbero grande efficacia sull'ingegno, specialmente de'Fi&shy;<lb/>siologi italiani, i quali dalle ipotesi passando ai fatti, trovarono che <lb/>davvero, sotto l'azione dell'elettricit&agrave;, s'eccitavano le membra agli <lb/>animali, &egrave; pi&ugrave; vivamente che mai ai pi&ugrave; sensibili, come alle rane. </s></p><p type="main">

<s>Uno de'pi&ugrave; indefessamente studiosi, tra questi Fisiologi, era il <lb/>bolognese Luigi Galvani, il quale fu fatto accorto, da coloro che lo <lb/>assistevano nelle esperienze, come le rane morte o scorticate si <lb/>commovevano, anche trovandosi fuori della sfera di azione della <lb/>macchina elettrica, a pur toccarne, con uno scalpello di ferro, i <lb/>nervi crurali. </s>

<s>Avendo trovato con sua gran sorpresa che il fatto <lb/>era vero, volle farne esperienza coll'elettricit&agrave; naturale, esponendo <lb/>all'aria le rane attaccate per un uncino alla ringhiera di ferro del <lb/>terrazzo, su cui davan le finestre di casa. </s>

<s>Sotto il ciel tempestoso, <lb/>osservava le solite commozioni che sotto l'azione della macchina <lb/>elettrica, non per&ograve; cos&igrave; a ciel sereno, bench&egrave; fosse fatto certo, dalle <lb/>osservazioni dell'elettometro, che l'aria, anche in quello stato me&shy;<lb/>teorologico, era imbevuta di elettricit&agrave; come sotto il ciel nuvoloso. </s>

<s><lb/>Ritornato a tentar per molti giorni, e non vedendoci risoluzione, <lb/>port&ograve; una di quelle rane, attaccate per l'uncino alla ringhiera, in <lb/>una stanza al coperto, e posatala sopra una lamiera di ferro, che <lb/>egli teneva per una mano, cominci&ograve; coll'altra a stuzzicare i nervi <lb/>del giacente animale, servendosi di quello stesso uncino, a cui era <lb/>affissa. </s>

<s>Si ridest&ograve; l'animo dell'intento osservatore a nuovi sensi <lb/>di maraviglia, quando vide seguitar da quell'atto le solite contra&shy;<lb/>zioni nelle gambe della rana, e i soliti guizzi. </s>

<s>Ripetuta l'esperienza <lb/>in varii altri modi, esult&ograve;, parendogli che venissero i fatti a sin-<pb xlink:href="020/01/265.jpg" pagenum="246"/>cerarlo dei dubbii del Newton, e delle congetture del Beccaria. </s>

<s>Il <lb/>fluido etereo, concluse, risiede ne'musculi dell'animale, i quali ve <lb/>lo tengono dentro condensato come l'elettricit&agrave; fra le due armature <lb/>di una bottiglia di Leyda: i nervi sono i conduttori di quel fluido <lb/>latente, che salta a commuover le membra all'animale, scaricandosi <lb/>attraverso a un arco di metallico, che fa l'ufficio di eccitatore. </s></p><p type="main">

<s>La storia della maravigliosa scoperta e delle esperienze, che <lb/>lo condussero ad essa, il Galvani ce la narr&ograve; ne'suoi pi&ugrave; minuti <lb/>particolari, nelle tre prime parti di un suo Commentario in latino <lb/>pubblicato in Bologna nel 1791. L'ultima parte di quel Commen&shy;<lb/>tario la riserb&ograve; l'Autore a dichiarare alcune sue congetture e con&shy;<lb/>seguenze di quel suo nuovo elettricismo animale. </s></p><p type="main">

<s>La lettura di quel Commentario eccit&ograve;, nell'animo de'Fisiologi, <lb/>commozioni non meno vive e inaspettate di quelle, che l'elettricit&agrave; <lb/>producesse ne'muscoli delle rane. </s>

<s>Chi pi&ugrave; di tutti poi si commosse <lb/>fu il Volta, il quale, trovate vere l'esperienze descritte dal Galvani, <lb/>a principio ne approv&ograve; anco insieme le congetture. </s>

<s>Altre esperienze <lb/>per&ograve; lo indussero poi in seguito a dubitarne, e fin&igrave; per convincersi <lb/>che non eran le rane da rassomigliarsi a bottiglie di Leyda, ma s&igrave; <lb/>meglio a sensibilissimi elettroscopi, svolgendosi ed eccitandosi il <lb/>fluido elettrico, non da'muscoli, ma dal contatto de'due metalli di <lb/>che si componevano gli archi eccitatori. </s>

<s>A confermare i contradi&shy;<lb/>centi in questa sua persuasione, dimostr&ograve; che sempre, al contatto <lb/>di due metalli di natura diversa, come sarebbe un disco di zinco <lb/>accoppiato a un altro di rame, si svolge un'elettricit&agrave; in tutto si&shy;<lb/>mile a quella, che si produce dai cilindri o dai dischi di vetro <lb/>confricati nelle macchine ordinarie. </s>

<s>E perch&egrave; l'elettricit&agrave; svolta da <lb/>sola una coppia metallica &egrave; debole, mostr&ograve; come si potevano far <lb/>concorrere insieme le virt&ugrave; di pi&ugrave; coppie, ponendo l'una in co&shy;<lb/>municazione coll'altra, o per mezzo dell'acqua pura, o per l'inter&shy;<lb/>posizione di dischi porosi imbevuti di acqua. </s>

<s>Di qui ebbe origine <lb/>quel portentoso elettromotore a tazze, e a pila, che il Volta stesso <lb/>descrive in sue varie scritture, ma specialmente nelle tre Lettere <lb/>al Gren, e in quell'altra al De-la-Metherie; lettere che si possono <lb/>veder raccolte nella II Parte del Tomo II delle Opere, stampate <lb/>nel 1816, in Firenze. </s></p><p type="main">

<s>Le applicazioni della Pila voltaia son note oramai ai dotti e <lb/>al volgo, com'&egrave; nota la stessa sfera del sole, ma non era nostra <lb/>intenzione d'accennar se non a sole quelle applicazioni, che pi&ugrave; <lb/>specialmente concernon la chimica. </s>

<s>L'elettricit&agrave; dinamica, scriveva <pb xlink:href="020/01/266.jpg" pagenum="247"/>lo stesso Volta, apre un campo fecondo di nuove speculazioni e <lb/>ricerche intorno all'influenza del fluido elettrico ne'fenomeni chi&shy;<lb/>mici, alle mutue relazioni di questi con quelle &rdquo; (Opera cit. </s>

<s>T. II, <lb/>P. II. pag. </s>

<s>142), e cos&igrave; appunto scriveva, il celebre inventor della <lb/>Pila, rispondendo al Landriani, il quale gli annunziava come il <lb/>Nicholson a Londra era felicemente riuscito a decompor l'acqua <lb/>fredda. </s>

<s>Presto s'avverarono que'presentimenti del Volta, quando, <lb/>oltre all'acqua, si decomposero i sali; di che si trov&ograve; la Pila aver <lb/><figure id="id.020.01.266.1.jpg" xlink:href="020/01/266/1.jpg"/><lb/>la pi&ugrave; squisita virt&ugrave; analitica. </s>

<s>Il veder gli acidi concorrere costan&shy;<lb/>temente al polo positivo, e le basi al negativo, parve ai chimici <lb/>una sperimentale dimostrazione di ci&ograve; che avea sospettato il Newton, <lb/>quando scrisse, ne'principii della Questione XXXI: &ldquo; et fortasse <lb/>attractio electrica ad huiusmodi exigua intervalla extendi potest, <lb/>etiamsi non excitetur frictione. </s>

<s>&rdquo; Ammisero infatti i Chimici che <lb/>fossero le molecole circondate da ammosfere elettriche, le quali <lb/>perturbate, fosser cagione del portarsi ciascuna di quelle molecole, <lb/>per attrazione, al polo di nome contrario. </s></p><pb xlink:href="020/01/267.jpg" pagenum="248"/><p type="main">

<s>Cos&igrave; ebbe origine l'elettrochimica, di che il Volta stesso, nella <lb/>citata risposta al Landriani, accenna ai principii e a'primi fonda&shy;<lb/>menti posti da lui. </s>

<s>Ma molto prima aveva concorso, il celebre pro&shy;<lb/>fessor di Pavia, a promuover le chimiche scoperte con gli studii <lb/>sulle esalazioni delle varie arie infiammabili, da cui ebbero origine, <lb/>non diremo i moschetti e le prime lampade a gasse, che pure tanto <lb/>piacquero al Furstenberger, da farle sue; ma quel nuovo <emph type="italics"/>Eudio&shy;<lb/>metro,<emph.end type="italics"/> che fu trovato il pi&ugrave; squisito strumento, da servire all'analisi <lb/>volumetrica de'corpi aerosi. </s></p><p type="main">

<s>La Meteorologia elettrica ebbe pure efficacissimi impulsi, per <lb/>opera del Volta e del Beccaria, a cui si dee la pratica applicazione <lb/>de'parafulmini in Italia, e gli studii sopra l'elettricit&agrave; a ciel sereno. </s>

<s><lb/>Ma bench&egrave;, s&igrave; il Franklin che lo stesso Beccaria, avessero dimo&shy;<lb/>strato in tante varie maniere l'esistenza dell'elettricit&agrave; nelle nubi, <lb/>non avevano conosciuto per&ograve; n&egrave; il modo n&egrave; l'origine di quelli <lb/>effluvi. </s>

<s>La scoperta di ci&ograve; occorse al Volta nel fare in Parigi, in <lb/>compagnia del Lavoisier e del La-Place, esperienze sull'elettricit&agrave; <lb/>che si svolge, quando l'acqua si trasforma in vapore. </s>

<s>&ldquo; L'esperienze <lb/>fatte fin qui, egli scrive nell'Appendice alla II Parte della Memoria <lb/>sul Condensatore, bench&egrave; non sien molte, tutte per&ograve; concorrono a <lb/>mostrarci che i vapori dell'acqua, e generalmente le parti d'ogni <lb/>corpo, che si staccan volatizzandosi, portano via seco una quantit&agrave; <lb/>di fluido elettrico, a spese dei corpi fissi che rimangono, lasciandoli <lb/>perci&ograve; elettrizzati negativamente &rdquo; (Op. </s>

<s>cit. </s>

<s>T. II. P. I. pag. </s>

<s>275). <lb/>Cos&igrave; per analogia veniva a dimostrarsi l'origine dell'elettricit&agrave; po&shy;<lb/>sitiva delle nubi. </s></p><p type="main">

<s>Ma perch&egrave; il Volta, sempre nelle esperienze cercava lume alle <lb/>teorie, ricorreva col pensiero alle somiglianze, che passano tra questi <lb/>nuovi fatti elettrici e altri fatti calorifici nuovamente scoperti. </s>

<s>Il <lb/>Guglielmini, tre anni prima che fossero pubblicate le celebri Que&shy;<lb/>stioni neutoniane, aveva gi&agrave;, nel suo Trattato <emph type="italics"/>De sanguinis natura,<emph.end type="italics"/><lb/>fatto distinzione fra calore e luce, attribuendone la variet&agrave; dell'ef&shy;<lb/>fetto al vario modo di ondulare dell'etere. </s>

<s>&ldquo; Quid enim impedit <lb/>quominus undulationes iis similes, quae ab ignis agitatione profi&shy;<lb/>ciscuntur, etiam ab aliis motibus aetheri imprimantur? </s>

<s>An excita&shy;<lb/>bitur in retina igniculus, cum, presso oculo, lucis scintillae videntur <lb/>observari? </s>

<s>&rdquo; (Venetiis, 1701, pag. </s>

<s>93). Il Newton poi pi&ugrave; solenne&shy;<lb/>mente aveva esposto, sotto la solita forma di dubbio, il pensiero <lb/>che l'elettricit&agrave;, il calore e la luce si potessero ridurre al vario <lb/>moto del mezzo etereo, ci&ograve; che oggid&igrave; si ritien dai fisici per la <pb xlink:href="020/01/268.jpg" pagenum="249"/>pi&ugrave; probabile ipotesi, a ridurre in unit&agrave; di principio la molteplice <lb/>variet&agrave; dei nuovi fatti osservati. </s>

<s>Cos&igrave;, prima che s'accogliessero <lb/>d'unanime consenso queste dottrine, aveva il Volta trovata un'altra <lb/>analogia fra l'elettricit&agrave; e il calore. </s>

<s>L'acquistare infatti maggior <lb/>capacit&agrave;, rispetto al fluido elettrico, i corpi che si risolvono in va&shy;<lb/>pori, l'assomiglia a ci&ograve; che si osserva del calorico latente. </s>

<s>&ldquo; Chi <lb/>non sar&agrave; colpito, egli scrive, da cos&igrave; bella analogia, per cui l'elet&shy;<lb/>tricit&agrave; porta del lume alla novella dottrina del calore e ne riceve <lb/>a vicenda? </s>

<s>Parlo della dottrina del calor latente o specifico, come <lb/>si vuol chiamare, di cui Black e Wilke colle stupende loro scoperte <lb/>han gittato i semi &rdquo; (ivi, pag. </s>

<s>275). </s></p><p type="main">

<s><emph type="center"/>V.<emph.end type="center"/></s></p><p type="main">

<s>Quell'Antonio Conti, che va debitore della sua fama alla va&shy;<lb/>riet&agrave; dell'erudizione, e alla sua faccendiera eloquenza, scriveva in <lb/>una lettera del d&igrave; 16 Settembre 1747 a Francesco Maria Zanotti: <lb/>&ldquo; Pare adesso cangiarsi tutta la Filosofia e ridursi alle forze elet&shy;<lb/>triche, di cui tante sono l'esperienze in tutti i paesi &rdquo; (Lett. </s>

<s>d'il&shy;<lb/>lustri ital. </s>

<s>Milano 1830, pag. </s>

<s>127). Eppure non erano ancora, quando <lb/>il Conti cos&igrave; scriveva, uscite alla luce le nuove Filosofie del Bec&shy;<lb/>caria, del Galvani e del Volta. </s>

<s>Che non si fossero, dietro alla nuova <lb/>preda, i Naturalisti cacciati in troppo numero e con troppa furia, <lb/>non si potrebbe per verit&agrave; negare n&egrave; al Conti n&egrave; a qualche altro <lb/>che l'afferm&ograve;, pi&ugrave; giudizioso di lui. </s>

<s>Nonostante, quel creder che <lb/>tutti i misteri della Natura fossero rimasti fin allora occulti agli <lb/>occhi de'Filosofi, sotto un medesimo velo intessuto di materia elet&shy;<lb/>trica, giov&ograve;, non foss'altro, con gli stessi arditi tentativi, a far pro&shy;<lb/>gredire la scienza. </s></p><p type="main">

<s>De'tanti misteri, quel che pi&ugrave; vivamente frugasse la curiosit&agrave; <lb/>de'Fisiologi, era quello concernente il principio della vita, la quale <lb/>si rivela a noi principalmente, per la spontaneit&agrave; de'moti muscu&shy;<lb/>lari. </s>

<s>Il Cartesio, giocando sempre al suo solito di fantasia, aveva <lb/>ammesso che gli spiriti animali, stillati dal cerebro, scendessero <lb/>in uno o pi&ugrave; musculi, dalle fibre canoliculate de'quali passassero <lb/>nelle fibre di altri muscoli opposti, in modo da riversarvi dentro <lb/>tutti i loro succhi spiritosi e cos&igrave; impinguarli, mentre essi stessi <lb/>perci&ograve; ne rimanevano esausti. </s>

<s>&ldquo; Qua ratione omnes spiritus antea, <pb xlink:href="020/01/269.jpg" pagenum="250"/>contenti in his duobus musculis confluunt celerrime in unum eo&shy;<lb/>rum, et sic inflant et contrahunt eum, dum alter extenditur et re&shy;<lb/>mittitur &rdquo; (Passion. </s>

<s>animae, Francof. </s>

<s>1692, pag. </s>

<s>5). Da questo passo, <lb/>e da tutto ci&ograve; che nel resto del Trattato ne dice, si vede ben che <lb/>l'Autore non aveva nemmen la pi&ugrave; lontana idea dell'Anatomia mu&shy;<lb/>scolare, la quale fu per&ograve; posta dal Borelli per fondamento alle sue <lb/>nuove dottrine de'moti animali. </s>

<s>Nel Cap. </s>

<s>III della Parte II di quel&shy;<lb/>l'Opera insigne, rifiutati gli spiriti cartesiani, ammette l'esistenza <lb/>del succo nerveo, che, stillando in mezzo alle fibre muscolari e <lb/>mescendosi ivi alla linfa e al sangue, vi produce una sub&igrave;ta effer&shy;<lb/>vescenza, com'a versare olio di tartaro sullo spirito di vetriolo. <lb/></s>

<s>&ldquo; Igitur pariter in musculis non dissimilis mistura fieri potest, ex <lb/>quo fermentatio et ebullitio subitanea subsequatur, a cuius mole <lb/>porositates musculorum repleantur, et amplientur et consequantur <lb/>turgentia et inflatio &rdquo; (Romae 1681, pag. </s>

<s>57). </s></p><p type="main">

<s>Al principio vitale e troppo grossolano del Borelli il Newton <lb/>sostitu&igrave; il mezzo etereo, il quale s'incarn&ograve; nell'elettricismo animale <lb/>del Galvani, che, nonostant&egrave; le valide opposizioni del Volta, rimase <lb/>il pi&ugrave; sicuro rifugio, che avesse in s&egrave; la Fisiologia, intantoch&egrave; Vin&shy;<lb/>cenzio Malacarne giunse a rassomigliare il cervello a una vera pila <lb/>voltaia. </s>

<s>Pretender d'aver con ci&ograve; svelati i misteri della vita, sarebbe <lb/>senza dubbio una follia, ma pure, non si pu&ograve; negar che non sieno <lb/>pi&ugrave; sodisfacenti le ipotesi del Galvani, di quelle del Borelli, e sa&shy;<lb/>rebbe una ingratitudine il non riconoscer le benemerenze del Gal&shy;<lb/>vanismo nella Terapeutica. </s></p><p type="main">

<s>Molto prima che a svelare i misteri della vita animale, s'era <lb/>applicata l'elettricit&agrave; a spiegar le funzioni della vita vegetativa. </s>

<s>Da <lb/>che il Nollet, nel Discorso IV delle sue <emph type="italics"/>Ricerche sulle ragioni par&shy;<lb/>ticolari dell'elettricit&agrave;,<emph.end type="italics"/> dimostr&ograve; che il fluido elettrico aveva virt&ugrave; <lb/>d'accelerar l'evaporazione dell'umidit&agrave; delle piante e delle frutte, <lb/>si pens&ograve; da'Botanici che lo stesso fluido elettrico potesse efficace&shy;<lb/>mente concorrere nelle funzioni della vegetazione. </s>

<s>Perci&ograve; molti fu&shy;<lb/>rono coloro, che si misero dietro a questo nuovo genere di espe&shy;<lb/>rienze, fra'quali si distinse il Jallebert di Ginevra, a cui parve che <lb/>i bulbi de'narcisi, delle giunchiglie e dei giacinti pi&ugrave; rigogliosa&shy;<lb/>mente vegetassero nell'acqua delle caraffe elettrizzate, che no nelle <lb/>naturali. </s></p><p type="main">

<s>Il Beccaria, nel Cap. </s>

<s>VII del I Libro dell'<emph type="italics"/>Elettricismo,<emph.end type="italics"/> dietro <lb/>la considerazione di questi fatti, esprime cosi un suo pensiero: <lb/>&ldquo; Ora questo vapore elettrico, che spinto dall'arte entro i vegeta-<pb xlink:href="020/01/270.jpg" pagenum="251"/>bili, sensibilmente agevola ed accresce la loro nutritura e vegeta&shy;<lb/>zione, non sarebbe esso (giacch&egrave; la Natura l'ha in ogni corpo in <lb/>certa quantit&agrave; e misura universalmente distribuito) una delle prin&shy;<lb/>cipali cause efficienti delle suddette naturali funzioni ne'vegetabili <lb/>e negli animali? </s>

<s>&rdquo; (ediz. </s>

<s>cit. </s>

<s>pag. </s>

<s>125, 26). E prosegue ivi a con&shy;<lb/>fortare questo suo pensiero con altri pensieri scelti dalle <emph type="italics"/>Questioni<emph.end type="italics"/><lb/>del Newton, in cui si sospetta che, per mezzo del fluido etereo, <lb/>s'esercitino le funzioni del senso e della vita negli animali. </s>

<s>Cos&igrave;, la <lb/>Botanica sperava d'usufruir bene dell'elettricit&agrave;, non punto meno <lb/>di quel che ne avesse usufruito la Fisiologia, e poniamo che da <lb/>ambedue queste scienze si fosse raccolto qualche buon frutto, l'ab&shy;<lb/>bondanza per&ograve; non corrispose agli ardori delle prime concepute <lb/>speranze. </s></p><p type="main">

<s>Da tutt'altra parte che dalla Fisica elettrica, vennero nel se&shy;<lb/>colo XVIII, alla Botanica le speranze e l'efficacia de'suoi progressi. </s>

<s><lb/>Carlo Linneo aveva scoperto il mistero della fecondazione de'fiori <lb/>e avendo riconosciuto in essi organi e funzioni somigliantissime a <lb/>quelle degli animali, le design&ograve; co'medesimi nomi. </s>

<s>Cos&igrave; si distin&shy;<lb/>sero anco le piante in maschi e in femmine, e s'attribu&igrave; pure ad <lb/>esse un'intelligenza di amore, e si prescrissero nuovi riti alle loro <lb/>nozze. </s>

<s>Alla strana novit&agrave; annunziata dallo Svedese, recalcitrarono, <lb/>secondo il solito, molti, fra'quali uno de'pi&ugrave; illustri botanici d'Italia, <lb/>Giulio Pontedera. </s>

<s>L'autorit&agrave; di lui sarebbe stata di grande ostacolo <lb/>a introdur le nuove dottrine fra noi, se non gli fosse sorto incontro <lb/>uno scrittore, oggid&igrave; pochissimo conosciuto, il siciliano Filippo Arena, <lb/>che nel suo Trattato <emph type="italics"/>Della Natura e cultura de'fiori,<emph.end type="italics"/> messo in luce <lb/>nel 1768 in Palermo, conferm&ograve; con nuove osservazioni il sistema, <lb/>e dimostr&ograve; che le verit&agrave; scoperte dal Linneo s'estendevano ad ogni <lb/>maniera d'inflorescenza. </s></p><p type="main">

<s>A leggere il Trattato del Beccaria, che noi abbiamo oramai <lb/>citato pi&ugrave; volte, si vede che i Fisici avevano nell'Elettricit&agrave; sperato <lb/>di trovar non solo le recondite cause efficienti della vita delle piante <lb/>e degli animali, ma avevano altres&igrave; distese quelle loro ardite spe&shy;<lb/>ranze a scrutar altri di que'misteri, che la Natura celebra ne'pi&ugrave; <lb/>riposti suoi nascondigli. </s>

<s>Si trattava di riconoscer nell'elettricit&agrave; <lb/>l'origine di quel fuoco sotterraneo, l'esistenza del quale veniva <lb/>resa manifesta dalle fusioni de'metalli scavati, e dalle visibili eru&shy;<lb/>zioni de'Vulcani. </s>

<s>Da questo fatto del fuoco centrale bene consi&shy;<lb/>derato, e dagli effetti che naturalmente ne conseguitano, ebbe il <lb/>principio quella nuova scienza, la quale nel suo studio comprende <pb xlink:href="020/01/271.jpg" pagenum="252"/>tutta intera la Storia Naturale, e che ha avuto il nome proprio di <lb/>Geologia. </s></p><p type="main">

<s>La Geologia, che penetra addentro alle viscere della Terra, e <lb/>per riconoscerle nelle loro cause e ne'loro effetti ne notomizza la <lb/>materia, appartiene alla Fisica sottile, ed &egrave; perci&ograve; nata in questi <lb/>ultimi tempi, e risente, quanto pure &egrave; disposta a riceverli, gl'in&shy;<lb/>flussi neutoniani. </s>

<s>Notabile che questi influssi stranieri fossero pi&ugrave; <lb/>efficacemente sentiti da un Italiano, che non dal Burnet o dal <lb/>Woodward, i quali seguitaron piuttosto i metodi del rinnovato <lb/>aristotelismo cartesiano. </s></p><p type="main">

<s>Uno de'pi&ugrave; curiosi problemi, che si proponesse a risolvere ai <lb/>Naturalisti, era quello dell'esistenza delle reliquie fossili di alcuni <lb/>animali marini, che si trovano, anche scavando a fior di terra, di&shy;<lb/>spersi per le alture de'monti. </s>

<s>Leonardo da Vinci si rideva di co&shy;<lb/>loro, che volevan dire &ldquo; li nicchi esser prodotti dalla Natura in essi <lb/>monti, mediante le costellazioni &rdquo; affermando sapientemente che <lb/>essi eran reliquie di molluschi vissuti un tempo fa e, dopo morte, <lb/>ivi deposti dalle acque dei diluvii. </s></p><p type="main">

<s>Pi&ugrave; di due secoli dopo, uno de'pi&ugrave; grandi nostri Naturalisti, <lb/>Antonio Vallisnieri, a risolvere il difficile problema, non sapeva in <lb/>sostanza dir punto nulla di pi&ugrave; o di meglio di quel che ne avesse <lb/>detto gi&agrave; Leonardo. </s>

<s>Il Vallisnieri per&ograve;, in quel suo Trattato, in cui <lb/>descrive i varii crostacei e le produzioni di mare, che si trovan sui <lb/>monti di Verona, e pi&ugrave; particolarmente i pesci e le erbe marine, <lb/>che quasi imbalsamate si trovan fra una pagina schistosa e l'altra <lb/>comprese nelle pietre del monte Bolca; faceva inconsapevolmente <lb/>un gran passo, trattenendosi a esaminar que'fatti, che ne assicura&shy;<lb/>vano del ritiramento del mare, e delle trasformazioni sub&igrave;te dalla <lb/>faccia della Terra. </s>

<s>Altro gran passo poi fece lo stesso Vallisnieri, <lb/>quando, nell'altro Trattatello pi&ugrave; importante di quello che ora ab&shy;<lb/>biamo citato, sull'origine delle fontane, descriveva cos&igrave; avveduta&shy;<lb/>mente le direzioni e le disposizioni degli strati petrosi, quasi nuova <lb/>Anatomia sottile dell'ossatura de'monti. </s>

<s>Fu questa nuova anatomia <lb/>descrittiva, che serv&igrave; d'uno de'pi&ugrave; validi argomenti, da risolvere il <lb/>problema dell'origine delle produzioni marine fra terra; problema <lb/>che fu felicemente risoluto da Anton Lazzaro Moro, friulano, di&shy;<lb/>mostrando la seguente proposizione: &ldquo; Gli animali e vegetabili ma&shy;<lb/>rini, le cui spoglie in oggi o sopra o sotto certi monti si trovano, <lb/>nati, nutriti e cresciuti nelle marine acque, innanzi che que'monti <lb/>sopra la superficie del mare si alzassero, allora l&agrave; furono spinti <pb xlink:href="020/01/272.jpg" pagenum="253"/>dove ora esistono per lo pi&ugrave; impietriti, quando que'monti, uscendo <lb/>dal seno della terra coperta, si alzarono a quelle altezze in cui ora <lb/>si vedono &rdquo; (De crostacei, ecc. </s>

<s>Venezia 1740, pag. </s>

<s>231). La mecca&shy;<lb/>nica di questi sollevamenti, di che s'aveva a que'tempi sotto gli <lb/>occhi l'esempio nella nuova isola di Santorino, l'attribuiva il Moro <lb/>al fuoco sotterraneo. </s>

<s>Di questo fuoco per&ograve;, manifesto ne'fatti, non <lb/>si conosceva ancora la causa, e bench&egrave; il Lemery si avvisasse di <lb/>ritrovarla nelle chimiche combinazioni, e ne'loro effetti di effer&shy;<lb/>vescenza, parve nulladimeno assai meglio di ricorrere a quel panurgo <lb/>dell'elettricit&agrave;, per cui cos&igrave;, nel sopra citato Libro Dell'Elettricismo, <lb/>scriveva il Beccaria: &ldquo; Congetturo che circoli esso vapore (elettrico) <lb/>in particolare maniera per alcuni particolari sotterranei corpi; im&shy;<lb/>perocch&egrave; la sua grande attivit&agrave; non ne farebbe essa pensare che <lb/>sia egli principio motore del fuoco centrale, che i Filosofi hanno <lb/>riconosciuto dentro la Terra? </s>

<s>&rdquo; (pag. </s>

<s>225). </s></p><p type="main">

<s>Cos&igrave;, da pi&ugrave; parti, in Italia concorrevasi a confermare quei <lb/>fondamenti, che aveva posti Lazzaro Moro alla nuova scienza della <lb/>Geologia. </s>

<s>Come poi della stessa cultura di questa scienza si sien <lb/>fatta esclusiva gloria gli studiosi stranieri, troppo lungo sarebbe <lb/>a dire, ma le usurpazioni incominciarono infino da Odoardo King, <lb/>che, nel 1767, espose innanzi alla R. </s>

<s>Societ&agrave; di Londra, come spe&shy;<lb/>culazione sua propria, il sistema geologico pubblicato, trentasei anni <lb/>prima, dal nostro Friulano. </s>

<s>Forse intesero quegli inglesi di trar <lb/>larga usura delle inspirazioni, che ebbe il Moro a ricevere dall'in&shy;<lb/>glese Filosofia neutoniana, da lui invocata a varie occasioni, e verso <lb/>la quale si rivolge come a faro di sicurezza, quando teme di smar&shy;<lb/>rirsi in quell'alto mare, da nessun altro corso prima di lui. </s></p><p type="main">

<s>Meglio per&ograve; che le ipotesi degli elettricisti, venivano prepa&shy;<lb/>rando i progressi alla Geologia le nuove osservazioni e le nuove <lb/>esperienze di Lazzero Spallanzani. </s>

<s>Cimentando egli le produzioni <lb/>vulcaniche e le rocce primitive nel fuoco delle fornaci, concluse <lb/>che i filosofi troppo avevano esagerato nell'apprezzare il grado di <lb/>attivit&agrave; e di intensit&agrave; del fuoco centrale. </s>

<s>Ritrovava altres&igrave;, per queste <lb/>sue esperienze, che le lave al calore si risolvevano in un gasse, <lb/>d'origine misterioso al par di quello, in che si risolve e per cui <lb/>rendesi bollicosa l'acqua ghiacciata. </s>

<s>Alla elasticit&agrave; di questi gassi <lb/>credette lo Spallanzani di dover attribuire la forza di deizione delle <lb/>lave, in fin su alla bocca de'vulcani. </s>

<s>Ma perch&egrave; poi l'esperienze <lb/>parvero dimostrargli che quelle sole forze non erano sufficienti; <lb/>riconobbe in ci&ograve; l'opera, ch'ei dimostr&ograve; con varii argomenti effi-<pb xlink:href="020/01/273.jpg" pagenum="254"/>cacissima, delle acque circolanti sottoterra, trasformate in vapori. </s>

<s><lb/>Ora i Geologi moderni, cos&igrave; italiani come stranieri, professano le <lb/>medesime dottrine, senza punto risovvenirsi di ci&ograve; che fu scritto, <lb/>molti anni prima, nel Cap. </s>

<s>XXI <emph type="italics"/>De'Viaggi alle due Sicilie,<emph.end type="italics"/> dove <lb/>l'Autore osserva di pi&ugrave; come cosa notabile, bench&egrave; qualche mo&shy;<lb/>derno siasi creduto d'essere stato il primo a notarla &ldquo; che i vul&shy;<lb/>cani sparsi nel globo, e che attualmente gettan fuoco, sono o cir&shy;<lb/>condati dal mare, o poco da esso discosti, e che quelli che da lungo <lb/>hanno lasciato di bruciare, esistono ora la pi&ugrave; parte lungi da lui &rdquo; <lb/>(Opere, M&igrave;lano 1825, T. II, pag. </s>

<s>305); osservazione che soccorreva <lb/>opportunissima a confermare il sistema di Lazzaro Moro. </s>

<s>Le De&shy;<lb/>scrizioni de'Viaggi alle Due Sicilie e in alcune parti dell'Appennino, <lb/>son del resto uno de'pi&ugrave; varii, e de'pi&ugrave; ricchi monumenti, che <lb/>sia stato eretto in Italia, nel secolo XVIII, alla Storia Naturale, <lb/>che vi si trova discorsa per quasi ogni sua parte. </s>

<s>Ora il lettore <lb/>&egrave; istruito dallo scienziato che scopre cose nuove, ora &egrave; dilettato <lb/>dall'Alpinista, che descrive viaggi non pi&ugrave; tentati, qual sarebbe <lb/>l'ascesa e la discesa del cono dell'Etna, con che incomincia il <lb/>Capitolo IX. </s></p><p type="main">

<s>Le insigni scoperte anatomiche fatte in questo secolo, princi&shy;<lb/>palmente dal Valsalva e dal Morgagni, dal Cotugno e dallo Scarpa, <lb/>sembrava che dovessero ammannire ad altre scoperte nuove in <lb/>Fisiologia. </s>

<s>Ma que'grandi uomini, a differenza degli anatomici an&shy;<lb/>tichi, sapevano tutto insieme l'arte di descrivere e d'indurre, d'os&shy;<lb/>servare e di sperimentare. </s>

<s>Cos&igrave;, dop'avere il Cotugno scoperta la <lb/>linfa nel labirinto, e dop'aver lo Scarpa descritta la finestra rotonda <lb/>e il timpano secondario, risalgono alle pi&ugrave; alte e sottili speculazioni <lb/>fisiologiche e filosofiche intorno al senso dell'udito. </s>

<s>Lo Spallanzani, <lb/>non essendo anatomico, non poteva sperare di far scoperte fisiolo&shy;<lb/>giche in soggetto nuovo: egli torna perci&ograve; su soggetti tentati gi&agrave; <lb/>prima di lui, e che in lui ritrovano la loro soluzione finale. </s>

<s>Egli <lb/>&egrave; in vero, il primo a dimostrare il fatto della circolazione del san&shy;<lb/>gue, nel giro universale de'vasi, divinata dall'Harvey, e in soli gli <lb/>animali a sangue freddo mostrata dal Malpighi; egli &egrave; il primo a <lb/>illustrare, se non a scoprir la chimica della respirazione, e a di&shy;<lb/>mostrar che la pelle, in alcuni animali degl'infimi ordini, supplisce <lb/>largamente al difetto, e fa l'ufficio stesso de'polmoni. </s></p><p type="main">

<s>Occorre, in questo periodo della scienza sperimentale italiana, <lb/>un fatto, che a noi sembra degno di esser notato, ed &egrave; la relazione <lb/>intima e la corrispondenza che passa, fra gli studi de'Nostri e <pb xlink:href="020/01/274.jpg" pagenum="255"/>quegli degli stranieri. </s>

<s>Quanta differenza tra ci&ograve; che si osserva in <lb/>questo, e nel secolo precedente, quando, a indurre i nostri Acca&shy;<lb/>demici fiorentini a corrispondere con gli Accademici di Parigi, ci <lb/>bisognarono le insinuazioni di Michelangiolo Ricci, e l'Autorit&agrave; di <lb/>Leopoldo de'Medici! In questo secolo il Volta sperimenta a Parigi <lb/>col Lavoisier e col La-Place, come co'suoi pi&ugrave; familiari amici e <lb/>colleghi, e lo Spallanzani dedica al Nollet le sue esperienze sugli <lb/>animali, e all'Haller le sue fisiologiche speculazioni. </s>

<s>Sembra a noi <lb/>che l'anello di congiunzione, meglio che il Cartesio, sia stato il <lb/>Newton, il quale, avendo ricevuto lume dall'Italia, sull'Italia stessa <lb/>lo rimand&ograve; potentemente riflesso. </s>

<s>Altro soggetto degno di conside&shy;<lb/>razione ci si porge dal comparar, co'due precedenti, il secolo XIX. </s>

<s><lb/>Ora son nuovamente rotte le relazioni e i commerci di studi fra <lb/>italiani e stranieri, con questa differenza, che, mentre i Discepoli <lb/>di Galileo si tenevan da parte, per non si degnare degli stranieri, <lb/>ora invece gli stranieri si tengon da parte, perch&egrave; non si degnan <lb/>di noi. </s></p><p type="main">

<s><emph type="center"/>VI.<emph.end type="center"/></s></p><p type="main">

<s>Non infruttuoso riuscirebbe l'andare investigando le cause di <lb/>quell'altero contegno e di quello sprezzante riserbo, usato oggidi <lb/>dagli scienziati stranieri verso i nostri italiani. </s>

<s>Ma perch&egrave; ci&ograve; non <lb/>potrebbesi fare, senz'entrare in confronti, i quali sempre riescono <lb/>odiosi, e perch&egrave; sempre si vede seguitar male a colui, che si vuol <lb/>mettere a dar giudizio de'contemporanei, meglio &egrave; lasciar gli uo&shy;<lb/>mini, e rivolgere uno sguardo fuggitivo alle cose, considerando le <lb/>condizioni, in cui le scienze sperimentali si trovano al presente. </s></p><p type="main">

<s>Quella legge da noi pi&ugrave; volte ricordata, in conformit&agrave; della <lb/>quale il soggetto propostoci a investigar dalla mente procede dal&shy;<lb/>l'intelligibilit&agrave; della forma all'intelligibilit&agrave; della materia, e dalla <lb/>materia crassa prosegue via via alla pi&ugrave; sottile; si vede verificarsi <lb/>anche in questo nostro secolo, in cui par che l'intento de'fisici, <lb/>sia tutto rivolto a trovar, ne'moti e nelle altre affezioni dell'etere, <lb/>quell'unit&agrave; di principio, a cui, come a causa unica, ridurre quella <lb/>complicata moltiplicit&agrave; di effetti, che producon sui nostri sensi, <lb/>l'elettricit&agrave;, il calore e la luce. </s>

<s>Sotto questo lato perci&ograve; riguardata, <pb xlink:href="020/01/275.jpg" pagenum="256"/>non par che la scienza abbia nulla cambiato il suo andamento: <lb/>ella non ha fatto altro che accelerare, a proporzione della distanza, <lb/>que'primi impulsi che, infin dal primo entrar del secolo scorso, <lb/>ricev&egrave; dalla Filosofia neutoniana. </s>

<s>Quel compiacersi, che fanno i con&shy;<lb/>temporanei dello stato attuale, &egrave; forse una di quelle solite lusinghe, <lb/>in cui si trattien l'animo di un padre, che, qualunque ella sia, si <lb/>compiace della sua prole. </s>

<s>Ma non si pu&ograve; negar che la scienza fisica <lb/>sperimentale, oggid&igrave;, per lo troppo lungo decorrere, non sia defa&shy;<lb/>tigata, e perci&ograve; ella, o invoca il soccorso che si suole apprestare <lb/>agli ordini trascorsi, d'esser ritirata verso i suoi principii, o ella <lb/>aspetta che le sia trasfuso per le vene uno spirito di giovent&ugrave; no&shy;<lb/>vello. </s>

<s>Ella aspetta insomma o un altro Newton o un altro Galileo. </s></p><p type="main">

<s>A molti sembra che l'aspettato sia gi&agrave; venuto e salutano in <lb/>Carlo Darwin un nuovo Restauratore della scienza sperimentale. </s>

<s><lb/>Egli come Galileo, e come il Newton, pone a fondamento della sua <lb/>nuova Filosofia un principio semplicissimo, e che non pu&ograve; non es&shy;<lb/>sere ammesso e comprovato dall'esperienza di ognuno: il principio <lb/>che tutto quaggi&ugrave; si trasforma col tempo. </s></p><p type="main">

<s>Ecco una parola, con cui si esprime il concetto pi&ugrave; misterioso, <lb/>che sia nella vita e nella scienza dell'uomo. </s>

<s>Noi viviamo nel tempo, <lb/>e perci&ograve; non &egrave; possibile il definire a noi stessi che cosa sia il tempo, <lb/>giusto a quel modo che non &egrave; possibile il definir la figura e la gran&shy;<lb/>dezza del sole, all'occhio che &egrave; tutto immerso nella sfera del sole. </s>

<s><lb/>Ma pure, il tempo &egrave; uno degli elementi, che entrano a compor quel&shy;<lb/>l'altro non meno misterioso concetto di forza. </s>

<s>Galileo e il Newton <lb/>avevano piuttosto rappresentato le forze, con quell'altro elemento <lb/>loro componente, e che pare a prima vista men misterioso, lo spazio, <lb/>e perci&ograve; fecero uso della Geometria. </s>

<s>Il Darwin insiste sull'elemento <lb/>del tempo, e come quell'antico Archimede chiedeva che gli fosse <lb/>dato spazio sufficiente, e prometteva di trovar la forza necessaria <lb/>a commuovere l'Universo; cos&igrave; il Darwin non chiede che tempo, <lb/>e promette di svelar con esso molti de misteri della Natura. </s>

<s>Il <lb/>tempo &egrave; una dinamia, &egrave; una forza che opera instancabile sempre, <lb/>ma degli effetti della quale non ci avvediamo, se non quando i <lb/>momenti sieno in molto numero accumulati. </s>

<s>La nuova dinamica <lb/>darviniana non &egrave; trattata coi processi matematici, ma &egrave; pure una <lb/>matematica anch'essa, e l'Autore non si dilunga in sostanza dai <lb/>metodi e dai precetti neutoniani, secondo i quali convien prima, <lb/>nelle matematiche, investigare le quantit&agrave; delle forze e le ragioni. <lb/></s>

<s>&ldquo; Deinde, ubi in physicam descenditur, conferendae sunt hae ra-<pb xlink:href="020/01/276.jpg" pagenum="257"/>tiones cum phaenomenis ut innotescat quaenam virium conditiones <lb/>singulis corporum attractivorum generibus competant. </s>

<s>&rdquo; Se non che <lb/>il Darwin, non discende a trattar la Fisica, propriamente detta, ma <lb/>la Storia Naturale, e perci&ograve; le forze attrattive essendo differenti, <lb/>vengono anche designate con un nome speciale, qual'&egrave; quello di <lb/><emph type="italics"/>selezione.<emph.end type="italics"/> Nel conferir poi la ragione di quelle forze, coi fenomeni <lb/>particolari, il nuovo Filosofo si studia d'osservare i precetti del pi&ugrave; <lb/>antico Filosofo inglese, ed &egrave; per l'osservanza di quegli stessi pre&shy;<lb/>cetti, quando altro non gli si frapponga a rimuoverlo dalla retta via, <lb/>che vien condotto alle sue nuove scoperte. </s></p><p type="main">

<s>I germi di queste novit&agrave; per&ograve; scoppiano da radice pi&ugrave; antica <lb/>e di origine schiettamente italiana, intanto che, se la moderna Fi&shy;<lb/>losofia naturale f&ugrave; istituita nella patria del Newton, si pu&ograve; dir che <lb/>ella niente altro fa propriamente che ripigliare un costrutto rimasto <lb/>per lungo tempo interrotto sulla punta della penna, e per le carte <lb/>de'predecessori e de'contemporanei di Galileo. </s>

<s>Le sottili osserva&shy;<lb/>zioni che fa il Darwin intorno al feto degli animali d'ordini supe&shy;<lb/>riori, al qual feto ritrova le membra organizzate a quel modo, che <lb/>si convien meglio all'organismo di animali di specie inferiori; erano <lb/>state fatte prima in gran parte dal Falloppio, quando, a conciliar <lb/>la nuova Anatomia del Vesalio con quella di Galeno, dimostrava <lb/>che l'antico Maestro si poteva in certo modo scusar d'errore, per <lb/>avere attribuito all'uomo l'anatomia de'cani e delle scimmie, ri&shy;<lb/>scontrandosi veramente una tal somiglianza anatomica con gli ani&shy;<lb/>mali degli ordini inferiori, nel feto umano, n&egrave; essendone in tutto <lb/>cancellate le vestigie nel neonato. </s>

<s>Alcuni anzi de'pi&ugrave; curiosi pro&shy;<lb/>blemi naturali, che si proponga a risolvere la Filosofia darviniana, <lb/>trovano ne'principii professati dal Falloppio una soluzione pi&ugrave; di&shy;<lb/>retta, pi&ugrave; facile e pi&ugrave; dimostrativa. </s>

<s>Che se dalle osservazioni ana&shy;<lb/>tomiche si passa a quelle, che concernono gl'istinti animali, noi <lb/>non vediamo che nessuno de'pi&ugrave; celebri Naturalisti moderni possa <lb/>venire al confronto dell'Acquapendente, in quel suo Libro, che egli <lb/>intitol&ograve; <emph type="italics"/>De Brutorum loquela.<emph.end type="italics"/> Egli osserva il tuono vario e il vario <lb/>modular de'suoni negli animali, per esprimere le loro varie pas&shy;<lb/>sioni. </s>

<s>La descrizione che egli fa di una gallina, co'suoi pulcini in&shy;<lb/>torno, insidiata da un cane; il vario modo del chiocciar di lei, <lb/>quando impone a'suoi piccoli che si allontanino dal pericolo, quando <lb/>v&agrave; incontro al cane per invitarlo disperatamente alla battaglia, <lb/>quando finalmente, rimasta vincitrice, richiama a s&egrave; i suoi pulcini, <lb/>perch&egrave; tornin sicuri a ricoverarsi sotto la protezione delle ali ma-<pb xlink:href="020/01/277.jpg" pagenum="258"/>terne (Patavii, 1603, pag. </s>

<s>23, 24); son, fra le molte, una di quelle <lb/>pagine, che sarebbe difficile trovar l'eguale nella moderna lette&shy;<lb/>ratura darviniana. </s></p><p type="main">

<s>Ma il Falloppio e l'Acquapendente, professando cos&igrave; fatte dot&shy;<lb/>trine, seppero sinceramente mantenersi credenti in Dio e nella di&shy;<lb/>gnit&agrave; dell'anima umana, n&egrave; si vede in che i settatori della novella <lb/>Filosofia sappiano ritrovar giuste ragioni di non doverne imitare <lb/>gli esempi. </s>

<s>Perci&ograve;, se non possiam non approvare i nuovi metodi <lb/>e non plaudire alle scoperte fatte dai Filosofi novelli, non sappiamo <lb/>approvar quel loro ingerirsi a definir cose, che si spettano alla <lb/>Metafisica e alla Teologia. </s>

<s>E dall'altra parte se mal provvedono al <lb/>lieto e pacifico progredir della Scienza que'Naturalisti, che la vo&shy;<lb/>glion fare da Metafisici e da Teologi, mal provvedono a mantenere <lb/>in dignit&agrave; e in rispetto le loro contemplazioni que'Teologi, che <lb/>voglion farla da Naturalisti. </s></p><p type="main">

<s>Non &egrave; uscito mai fuori nessun sistema di Filosofia Naturale a <lb/>insegnar cose contrarie alla corrente opinione, che non si sia ten&shy;<lb/>tato di oppugnarlo con l'armi teologiche. </s>

<s>Per tacere del Coperni&shy;<lb/>cismo, le vicende del quale sono oramai troppo note, la vera scienza <lb/>sperimentale in Italia, e di li in tutta Europa, ebbe i primi prin&shy;<lb/>cipii e i pi&ugrave; validi impulsi, com'altre volte si &egrave; detto, dalla cele&shy;<lb/>berrima dimostrazione torricelliana del vacuo. </s>

<s>Insorsero, chi se lo <lb/>sarebbe aspettato mai? </s>

<s>i Teologi ad oppugnare anco questo fatto, <lb/>tassandolo di quell'eresia, derivata dagli errori epicurei, e secondo <lb/>la quale si veniva, a parer de'nuovi censori, a negar l'unione e la <lb/>conservazione nell'Universo. </s>

<s>Ma qual giudizio si facesse, infino dal <lb/>loro primo insorgere, di que'teologici argomenti, vogliamo ce lo <lb/>dica un uomo, il quale, essendo uno de'pi&ugrave; benemeriti de'pro&shy;<lb/>gressi delle scienze sperimentali in Italia, ed essendo dall'altra <lb/>parte monsignore in Roma e poi cardinale, &egrave; atto a inspirar, me&shy;<lb/>glio di qualunque altro, riverenza e tacito ossequio negli animi <lb/>de'professanti contrarie opinioni. </s>

<s>Michelangiolo Ricci, dop'avere in <lb/>una sua lettera riferito al Torricelli la nuova maniera d'argomentar <lb/>di que'Teologi, da'quali veniva l'Autor dell'esperienza dell'argento <lb/>vivo ad essere annoverato fra il gregge di Epicuro, cos&igrave; tosto pro&shy;<lb/>segue: &ldquo; Ci&ograve; sia detto con riverenza di V. S., la quale non vo'tediare <lb/>con altro che le potrei soggiungere appresso, in questa materia, <lb/>perch&egrave; stimo che sar&agrave; pur troppo nauseata dalla temeraria opinione <lb/>de'suddetti Teologi, e dal costume suo costante di mescolar subito <lb/>le cose di Dio ne'ragionamenti naturali, dovecch&egrave; quelle dovrebbero <pb xlink:href="020/01/278.jpg" pagenum="259"/>con maggior rispetto e riverenza esser trattate &rdquo; (MSS. Gal. </s>

<s>Disc. </s>

<s><lb/>T. XLII, c. </s>

<s>32). </s></p><p type="main">

<s>Ma perch&egrave; i dissidenti, a cui manca il senno e la scienza di <lb/>Michelangiolo Ricci, non &egrave; da sperare che sieno per convertirsi al <lb/>vero, persuasi dalle parole di lui, ci sentiam lieti in pensare e in <lb/>dovere avvertire i nostri lettori, che la Filosofia Naturale da cui <lb/>son venute alla scienza le vitali riforme e i bene augurati incre&shy;<lb/>menti, non entra affatto nella nostra Storia, soggetto della quale <lb/>non &egrave; propriamente che la Filosofia di Galileo e de'seguaci di lui <lb/>nella fiorentina Accademia del Cimento. </s>

<s>I secoli che precedettero <lb/>a questo, e quello che immediatamente lo segue, in tanto son per <lb/>noi soggetto storico, in quanto, in quegli stessi secoli anteriori si <lb/>prepararono, e nel posteriore si svolsero o s'infusero nuovi spiriti <lb/>di vita nelle dottrine insegnate e promulgate dalla scuola galileiana. </s></p><p type="main">

<s>La nostra Storia sar&agrave; ripartita in sette Tomi. </s>

<s>In questo primo, <lb/>al presente Discorso preliminare, seguiter&agrave; la storia dell'invenzione <lb/>de'principali strumenti, che servono al Metodo sperimentale. </s>

<s>Nel <lb/>secondo, si dar&agrave; la storia del Metodo sperimentale applicato alle <lb/>scienze fisiche, e nel terzo narreremo i progressi fatti, per l'appli&shy;<lb/>cazione dello stesso metodo, da quella, a cui diamo nel pi&ugrave; largo <lb/>significato il nome di Storia Naturale. </s></p><p type="main">

<s>Con questi primi tre Tomi sembrerebbe che si fosse sodisfatto, <lb/>in qualche modo, al debito che ci siamo imposti. </s>

<s>Ma se pu&ograve; dirsi <lb/>che siasi cos&igrave; storicamente dimostrato ai nostri lettori come la <lb/>scuola galileiana, applicando i metodi sperimentali abbia scoperto <lb/>verit&agrave; nuove, in ogni parte della Natura; non saremmo per&ograve; an&shy;<lb/>cora penetrati addentro a scoprir da quali occulte radici attingessero, <lb/>quegli stessi metodi, i succhi nutritizii. </s>

<s>Que'succhi dell'altra parte <lb/>derivano sottilmente stillati, e vitalmente trasfusi nella nuova arte <lb/>sperimentale, dalla scienza del moto, ignorandosi la quale, vien <lb/>necessariamente a ignorarsi ogni altra scienza della Natura. </s>

<s>E per&shy;<lb/>ci&ograve;, mentre in quei tre primi Tomi la nostra Storia pareva essere <lb/>di ogni parto assoluta, ora si comprende come, terminandosi qui, <lb/>a quell'edifizio che studiosamente attendiamo a costruire manche&shy;<lb/>rebbero le fondamenta, fondamenta che noi poniamo ne'due Tomi <lb/>appresso, dove si narra la storia de'processi dimostrativi matema&shy;<lb/>tici e sperimentali della Meccanica. </s>

<s>Nel Tomo IV perci&ograve;, si d&agrave; <lb/>la storia delle dottrine meccaniche di Galileo, e nel V vedremo <lb/>come fossero quelle stesse dottrine svolte e confermate da'seguaci <lb/>di lui. </s></p><pb xlink:href="020/01/279.jpg" pagenum="260"/><p type="main">

<s>Ma perch&egrave; apparisca anche meglio evidente la verit&agrave; di quel&shy;<lb/>l'antica sentenza, pronunziata dal Filosofo, che cio&egrave;, <emph type="italics"/>ignorato motu <lb/>ignoratur Natura,<emph.end type="italics"/> abbiamo sentito vivo il bisogno di mostrar come <lb/>fosse la Meccanica immediatamente feconda di un'altra scienza, al <lb/>pari di lei Nuova, e al pari di lei Italiana di origine e di cultura; <lb/>scienza che &egrave; una delle pi&ugrave; splendide e pi&ugrave; benefiche applicaz&igrave;oni <lb/>delle matematiche astratte alle naturali esperienze. </s>

<s>Gli altri due <lb/>Tomi perci&ograve; s'intratterranno intorno alla Storia dell'Idraulica, nar&shy;<lb/>randosi di lei nel VI Tomo l'origine e i progressi fatti per opera <lb/>di Galileo e del Castelli, e riserbando il VII a mostrare in qual <lb/>grado di perfezione fosse ridotta la scienza del Moto delle acque <lb/>da'discepoli e da'seguaci de'due grandi Maestri. </s>

<s>E perch&egrave;, nell'ap&shy;<lb/>plicazione del metodo sperimentale, oltre alle scienze fisiche, hanno <lb/>sperato di trovar aiuti e validi impulsi a progredire, anche le scienze <lb/>morali, se ci basteranno le forze dell'ingegno, daremo anche di ci&ograve; <lb/>qualche saggio: e perch&egrave; tutto il nostro lavoro storico &egrave; condotto <lb/>sui documenti, per la massima parte non molto noti, se l'acco&shy;<lb/>glienza de'lettori ci dar&agrave; qualche speranza che non sieno per riuscire <lb/>inutili affatto le nostre fatiche, ai sette gi&agrave; designati faremo suc&shy;<lb/>cedere via via, come Appendice alla nostra Storia, altri volumi. </s></p><p type="main">

<s>Al pararsi innanzi la macchina di questo ponderoso edifizio, <lb/>sentiamo gemerci sotto affaticate le nostre povere spalle, che ora <lb/>procedono vacillanti, ora temono il pi&ugrave; grave pericolo di rimanere <lb/>oppresse. </s>

<s>Ma comunque ci avvenga di poter condurre al desiderato <lb/>termine l'Opera nostra, non &egrave; credibile che ella non debba riuscir <lb/>per moltissime parti difettosa. </s>

<s>E perch&egrave; sappiano i lettori che non <lb/>si dice ci&ograve; per iscusa o per modestia, ma perch&egrave; siamo fermamente <lb/>persuasi in quella credenza, accenneremo ad una delle principali <lb/>occasioni, d'onde inevitabilmente avranno origine i pi&ugrave; temuti fra <lb/>que'difetti. </s></p><p type="main">

<s>La storia della scienza ha avuto sempre una certa predilezione <lb/>nella cultura, qualunque ella siasi, de'nostri studi. </s>

<s>Gi&agrave;, infin dal&shy;<lb/>l'anno 1878, si mandava a Roma, all'egregio Principe D. </s>

<s>Baldassarre <lb/>Boncompagni, alcune <emph type="italics"/>Notizie Storiche intorno all'invenzione del <lb/>Termometro,<emph.end type="italics"/> pubblicate, in quello stesso anno, nel <emph type="italics"/>Bullettino di <lb/>bibliografia e di storia delle scienze matematiche e fisiche,<emph.end type="italics"/> nel fa&shy;<lb/>scicolo del Settembre. </s>

<s>Dal 1878 al 1885 le <emph type="italics"/>Letture di Famiglia<emph.end type="italics"/><lb/>dispensavano a sorsi, in Firenze, alcune nostre scritture in forma <lb/>di Lezioni, contenenti <emph type="italics"/>Saggi di storia della Fisica sperimentale <lb/>italiana,<emph.end type="italics"/> dai tempi di Dante a quelli di Galileo: scritture che si <pb xlink:href="020/01/280.jpg" pagenum="261"/>interpolavano, nello stesso Periodico, con altre sotto il titolo di <emph type="italics"/>Ri&shy;<lb/>creazioni scientifiche,<emph.end type="italics"/> raccolte e pubblicate dal Direttore, pure in <lb/>Firenze, nel 1883, in un volumetto elegante. </s>

<s>Anche nel dare quelle <lb/>Nozioni di Fisica e di Botanica, sotto le dilettevoli forme di Rac&shy;<lb/>conto o di domestiche scene, in que'due libretti, che portano il titolo <lb/>di <emph type="italics"/>Estate in Montagna<emph.end type="italics"/> e <emph type="italics"/>Fra il Ver