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| <?xml version="1.0"?> | <?xml version="1.0"?> |
| <!DOCTYPE archimedes SYSTEM "../dtd/archimedes.dtd" ><archimedes> <info> | <!DOCTYPE archimedes SYSTEM "../dtd/archimedes.dtd" ><archimedes> <info> |
| <author>Galilei, Galileo</author> | <author>Galilei, Galileo</author> |
| <title>Natation</title> | <title>Mechanics</title> |
| <date>1663</date> | <date>1665</date> |
| <place>London</place> | <place>London</place> |
| <translator>Thomas Salusbury</translator> | <translator>Thomas Salusbury</translator> |
| <lang>en</lang> | <lang>en</lang> |
| <cvs_file>galil_natat_074_en_1663.xml</cvs_file> | <cvs_file>galil_mecha_070_en_1665.xml</cvs_file> |
| <cvs_version></cvs_version> | <cvs_version></cvs_version> |
| <locator>074.xml</locator> | <locator>070.xml</locator> |
| </info> <text> <front> <section> | </info> <text> <front> <section> |
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| <pb/> | <pb xlink:href="070/01/001.jpg" pagenum="271"/><p type="head"> |
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| <p type="head"> | <s>GALILEUS, <lb/>HIS <lb/>MECHANICKS: <lb/>OF THE BENEFIT DERIVED <lb/>FROM THE SCIENCE OF MECHANICKS, <lb/>AND FROM ITS INSTRUMENTS.</s></p> </section> </front> <body> <chap> <p type="main"> |
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| <s>A <lb/>DISCOURSE <lb/><emph type="italics"/>PRESENTED<emph.end type="italics"/><lb/>TO THE MOST SERENE <lb/>Don Co&longs;imo II. <lb/>GREAT DUKE <lb/><emph type="italics"/>OF<emph.end type="italics"/><lb/>TUSCANY, <lb/>CONCERNING <lb/>The <emph type="italics"/>NATATION<emph.end type="italics"/> of BODIES Vpon, <lb/>And <emph type="italics"/>SUBMERSION<emph.end type="italics"/> In, <lb/>THE <lb/>WATER.</s></p><p type="head"> | <s>I judged it extreamly nece&longs;&longs;ary, before our <lb/>de&longs;cending to the Speculation of Mecha­<lb/>nick In&longs;truments, to con&longs;ider how I might, <lb/>as it were, &longs;et before your eyes in a gene­<lb/>ral Di&longs;cour&longs;e, the many benefits that are <lb/>derived from the &longs;aid In&longs;truments: and <lb/>this I have thought my &longs;elf the more ob­<lb/>liged to do, for that (if I am not mi&longs;taken) <lb/>I have &longs;een the generality of <emph type="italics"/>M<emph.end type="italics"/>echaniti­<lb/>ans deceive them&longs;elves in going about to apply Machines to many <lb/>operations of their own nature impo&longs;&longs;ible; by the &longs;ucce&longs;&longs;e where­<lb/>of they have been di&longs;appointed, and others likewi&longs;e fru&longs;trate of <lb/>the hope which they had conceived upon the promi&longs;e of tho&longs;e pre­<lb/>&longs;umptuous undertakers: of which mi&longs;takes I think I have found <lb/>the principall cau&longs;e to be the belief and con&longs;tant opinion the&longs;e <pb xlink:href="070/01/002.jpg" pagenum="272"/>Artificers had, and &longs;till have, that they are able with a &longs;mall force <lb/>to move and rai&longs;e great weights; (in a certain manner with their <lb/>Machines cozening nature, who&longs;e In&longs;tinct, yea mo&longs;t po&longs;itive con­<lb/>&longs;titution it is, that no Re&longs;i&longs;tance can be overcome, but by a Force <lb/>more potent then it:) which conjecture how fal&longs;e it is, I hope by <lb/>the en&longs;uing true and nece&longs;&longs;ary Demon&longs;trations to evince.</s></p><p type="main"> |
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| <s>By GALILEUS GALILEI: Philo&longs;opher and <lb/>Mathematician, unto His mo&longs;t Serene Highne&longs;&longs;e.</s></p><p type="head"> | <s>In the mean time, &longs;ince I have hinted, that the benefit and help <lb/>derived from Machines is not, to be able with le&longs;&longs;e Force, by help <lb/>of the Machine to move tho&longs;e weights, which, without it, could <lb/>not be moved by the &longs;ame Force: it would not be be&longs;ides the <lb/>purpo&longs;e to declare what the Commodities be which are derived to <lb/>us from &longs;uch like faculties, for if no profit were to be hoped for, <lb/>all endeavours employed in the acqui&longs;t thereof will be but lo&longs;t <lb/>labour.</s></p><p type="main"> |
| | |
| <s>Engli&longs;hed from the Second Edition of the ITALIAN, <lb/>compared with the Manu&longs;cript Copies, and reduced <lb/>into PROPOSITIONS: <lb/>By <emph type="italics"/>THOMAS SALUSBURY,<emph.end type="italics"/> <expan abbr="E&longs;q;">E&longs;que</expan></s></p><p type="head"> | <s>Proceeding therefore according to the nature of the&longs;e Studies, <lb/>let us fir&longs;t propo&longs;e four things to be con&longs;idered. </s> |
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| <s><emph type="italics"/>LONDON<emph.end type="italics"/>: <lb/>Printed by WILLIAM LEYBOURN: <lb/><emph type="italics"/>M D C LXIII.<emph.end type="italics"/></s></p></section><section> | |
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| | |
| <pb pagenum="401"/><p type="head"> | |
| | |
| <s>A DISCOVRSE <lb/>Pre&longs;ented to the Mo&longs;t Serene DON COSIMO II. <lb/>GREATDUKE of <emph type="italics"/>TUSC ANY:<emph.end type="italics"/><lb/>CONCERNING<lb/><emph type="italics"/>The Natation of BODIES Upon, or Submer&longs;ion <lb/>In, the WATER.<emph.end type="italics"/></s> </p></section> </front> <body> <chap><p type="main"> | |
| | |
| <s>Con&longs;idering (Mo&longs;t Serene Prince) that the <lb/>publi&longs;hing this pre&longs;ent Treati&longs;e, of &longs;o <lb/>different an Argument from that which <lb/><arrow.to.target n="marg1393"></arrow.to.target><lb/>many expect, and which according to the <lb/>intentions I propo&longs;ed in my ^{*} A&longs;tronomi­<lb/>call <emph type="italics"/>Advi&longs;o,<emph.end type="italics"/> I &longs;hould before this time <lb/>have put forth, might peradventure make <lb/>&longs;ome thinke, either that I had wholly <lb/>relinqui&longs;hed my farther imployment <lb/>about the new Cele&longs;tiall Ob&longs;ervations, <lb/>or that, at lea&longs;t, I handled them very <lb/>remi&longs;&longs;ely; I have judged fit to render an account, a&longs;well of my <lb/>deferring that, as of my writing, and publi&longs;hing this treati&longs;e.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1393"></margin.target>His Nuncio Sl­<lb/>derio.</s></p><p type="main"> | |
| | |
| <s>As to the fir&longs;t, the la&longs;t di&longs;coveries of <emph type="italics"/>Saturn<emph.end type="italics"/> to be tricorporeall, and <lb/>of the mutations of Figure in <emph type="italics"/>Venus,<emph.end type="italics"/> like to tho&longs;e that are &longs;een in the | |
| <lb/>Moon, together with the Con&longs;equents depending thereupon, have | |
| <lb/>not &longs;o much occa&longs;ioned the demur, as the inve&longs;tigation of the times | |
| <lb/>of the Conver&longs;ions of each of the Four Medicean Planets about <emph type="italics"/>Ju­ | |
| <lb/>piter,<emph.end type="italics"/> which I lighted upon in <emph type="italics"/>April<emph.end type="italics"/> the year pa&longs;t, 1611, at my being in | |
| <lb/><emph type="italics"/>Rome<emph.end type="italics"/>; where, in the end, I a&longs;&longs;ertained my &longs;elfe, that the fir&longs;t and neere&longs;t | |
| <lb/>to <emph type="italics"/>Jupiter,<emph.end type="italics"/> moved about 8 <emph type="italics"/>gr.<emph.end type="italics"/> & 29 <emph type="italics"/>m.<emph.end type="italics"/> of its Sphere in an houre, make­ | |
| <lb/>ing its whole revolution in one naturall day, and 18 hours, and almo&longs;t | |
| <lb/>an halfe. </s><s>The &longs;econd moves in its Orbe 14 <emph type="italics"/>gr. </s><s>13 min.<emph.end type="italics"/> or very neer, | |
| <lb/>in an hour, and its compleat conver&longs;ion is con&longs;ummate in 3 dayes, 13 | |
| <lb/>hours, and one third, or thereabouts. </s><s>The third pa&longs;&longs;eth in an hour, | |
| <lb/>2 <emph type="italics"/>gr. </s><s>6 min.<emph.end type="italics"/> little more or le&longs;s of its Circle, and mea&longs;ures it all in 7 | |
| <lb/>dayes, 4 hours, or very neer. </s><s>The fourth, and more remote than the | |
| <lb/>re&longs;t, goes in one houre, o <emph type="italics"/>gr 54 min.<emph.end type="italics"/> and almo&longs;t an halfe of its Sphere, | |
| <lb/>and fini&longs;heth it all in 16 dayes, and very neer 18 hours. </s><s>But be­ | |
| <lb/>cau&longs;e the exce&longs;&longs;ive velocity of their returns or re&longs;titutions, requires a | |
| <lb/>mo&longs;t &longs;crupulous preci&longs;ene&longs;&longs;e to calculate their places, in times pa&longs;t | |
| | |
| | |
| <pb pagenum="402"/>and future, e&longs;pecially if the time be for many Moneths or Years; I | |
| <lb/>am therefore forced, with other Ob&longs;ervations, and more exact than | |
| <lb/>the former, and in times more remote from one another, to correct | |
| <lb/>the Tables of &longs;uch Motions, and limit them even to the &longs;horte&longs;t mo­ | |
| <lb/>ment: for &longs;uch exactne&longs;&longs;e my fir&longs;t Ob&longs;ervations &longs;uffice not; not only | |
| <lb/>in regard of the &longs;hort intervals of Time, but becau&longs;e I had not as then | |
| <lb/>found out a way to mea&longs;ure the di&longs;tances between the &longs;aid Planets | |
| <lb/>by any In&longs;trument: I Ob&longs;erved &longs;uch Intervals with &longs;imple relation | |
| <lb/>to the Diameter of the Body of <emph type="italics"/>Jupiter<emph.end type="italics"/>; taken, as we have &longs;aid, by | |
| <lb/>the eye, the which, though they admit not errors of above a Minute, | |
| <lb/>yet they &longs;uffice not for the determination of the exact greatne&longs;s of the | |
| <lb/>Spheres of tho&longs;e Stars. </s><s>But now that I have hit upon a way of ta­ | |
| <lb/>king &longs;uch mea&longs;ures without failing, &longs;carce in a very few Seconds, I will | |
| <lb/>continue the ob&longs;ervation to the very occultation of <emph type="italics"/>JVPITER,<emph.end type="italics"/> | |
| <lb/>which &longs;hall &longs;erve to bring us to the perfect knowledge of the Moti­ | |
| <lb/>ons, and Magnitudes of the Orbes of the &longs;aid Planets, together | |
| <lb/><arrow.to.target n="marg1394"></arrow.to.target> | |
| <lb/>al&longs;o with &longs;ome other con&longs;equences thence ari&longs;ing. </s><s>I adde to the&longs;e | |
| <lb/>things the ob&longs;ervation of &longs;ome ob&longs;cure Spots, which are di&longs;cover­ | |
| <lb/>ed in the Solar Body, which changing, po&longs;ition in that, propounds | |
| <lb/>to our con&longs;ideration a great argument either that the Sun revolves in | |
| <lb/>it &longs;elfe, or that perhaps other Starts, in like manner as <emph type="italics"/>Venus<emph.end type="italics"/> and | |
| <lb/><emph type="italics"/>Mercury,<emph.end type="italics"/> revolve about it, invi&longs;ible in other times, by rea&longs;on of their | |
| <lb/>&longs;mall digre&longs;&longs;ions, le&longs;&longs;e than that of <emph type="italics"/>Mercury,<emph.end type="italics"/> and only vi&longs;ible when | |
| <lb/>they interpo&longs;e between the Sun and our eye, or el&longs;e hint the truth | |
| <lb/>of both this and that; the certainty of which things ought not to be | |
| <lb/>contemned, nor omitted.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1394"></margin.target>The Authors | |
| <lb/>Ob&longs;ervations of | |
| <lb/>the Solar Spots.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Continuall ob&longs;ervation hath at la&longs;t a&longs;&longs;ured me that the&longs;e Spots are | |
| <lb/>matters contiguous to the Body of the Sun, there continually produced | |
| <lb/>in great number, and afterwards di&longs;&longs;olved, &longs;ome in a &longs;horter, &longs;ome in a | |
| <lb/>longer time, and to be by the Conver&longs;ion or Revolution of the Sun in it | |
| <lb/>&longs;elfe, which in a Lunar Moneth, or thereabouts, fini&longs;heth its Period, | |
| <lb/>caried about in a Circle, an accident great of it &longs;elfe, and greater for | |
| <lb/>its Con&longs;equences.<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1395"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1395"></margin.target>The occa&longs;ion in­ | |
| <lb/>ducing the Au­ | |
| <lb/>thor to write | |
| <lb/>this Treati&longs;e.</s></p><p type="main"> | |
| | |
| <s>As to the other particular in the next place. ^{*} Many cau&longs;es have | |
| <lb/>moved me to write the pre&longs;ent Tract, the &longs;ubject whereof, is the | |
| <lb/>Di&longs;pute which I held &longs;ome dayes &longs;ince, with &longs;ome learned men of | |
| <lb/>this City, about which, as your Highne&longs;&longs;e knows, have followed | |
| <lb/>many Di&longs;cour&longs;es: The principall of which Cau&longs;es hath been the | |
| <lb/>Intimation of your Highne&longs;&longs;e, having commended to me Writing, | |
| <lb/>as a &longs;ingular means to make true known from fal&longs;e, reall from appa­ | |
| <lb/>rent Rea&longs;ons, farr better than by Di&longs;puting vocally, where the | |
| <lb/>one or the other, or very often both the Di&longs;putants, through too | |
| | |
| | |
| <pb pagenum="403"/>greate heate, or exalting of the voyce, either are not under&longs;tood, | |
| <lb/>or el&longs;e being tran&longs;ported by o&longs;tentation of not yeilding to one ano­ | |
| <lb/>ther, farr from the fir&longs;t Propo&longs;ition, with the novelty, of the | |
| <lb/>various Propo&longs;als, confound both them&longs;elves and their Auditors.</s></p><p type="main"> | |
| | |
| <s>Moreover, it &longs;eemed to me convenient to informe your High­ | |
| <lb/>ne&longs;&longs;e of all the &longs;equell, concerning the Controver&longs;ie of which I | |
| <lb/>treat, as it hath been adverti&longs;ed often already by others: and becau&longs;e | |
| <lb/>the Doctrine which I follow, in the di&longs;cu&longs;&longs;ion of the point in hand, | |
| <lb/>is different from that of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/>; and interferes with his Principles, | |
| <lb/>I have con&longs;idered that again&longs;t the Authority of that mo&longs;t famous | |
| <lb/>Man, which among&longs;t many makes all &longs;u&longs;pected that comes not from | |
| <lb/>the Schooles of the Peripateticks, its farr better to give ones Rea&longs;ons | |
| <lb/>by the Pen than by word of mouth and therfore I re&longs;olved to write the | |
| <lb/>pre&longs;ent di&longs;cour&longs;e: in which yet I hope to demon&longs;trate that it was not | |
| <lb/>out of capritiou&longs;ne&longs;&longs;e, or for that I had not read or under&longs;tood | |
| <lb/><emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> that I &longs;ometimes &longs;werve from his opinion, but becau&longs;e | |
| <lb/>&longs;everall Rea&longs;ons per&longs;wade me to it, and the &longs;ame <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> hath </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1396"></arrow.to.target> | |
| <lb/>tought me to fix my judgment on that which is grounded upon | |
| <lb/>Rea&longs;on, and not on the bare Authority of the Ma&longs;ter; and it is | |
| <lb/>mo&longs;t certaine according to the &longs;entence of <emph type="italics"/>Alcinoos,<emph.end type="italics"/> that philo&longs;opha­ | |
| <lb/><arrow.to.target n="marg1397"></arrow.to.target> | |
| <lb/>ting &longs;hould be free. </s><s>Nor is the re&longs;olution of our Que&longs;tion in my | |
| <lb/>judgment without &longs;ome benefit to the Univer&longs;all, fora&longs;much as | |
| <lb/>treating whether the figure of Solids operates, or not, in their going, | |
| <lb/>or not going to the bottome in Water, in occurrences of building | |
| <lb/>Bridges or other Fabricks on the Water, which happen commonly | |
| <lb/>in affairs of grand import, it may be of great availe to know the | |
| <lb/>truth.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1396"></margin.target><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> prefers | |
| <lb/>Rea&longs;on to the | |
| <lb/>Authority ofan | |
| <lb/>Author.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1397"></margin.target>The benefit of | |
| <lb/>this Argument.</s></p><p type="main"> | |
| | |
| <s>I &longs;ay therfore, that being the la&longs;t Summer in company with certain | |
| <lb/><arrow.to.target n="marg1398"></arrow.to.target> | |
| <lb/>Learned men, it was &longs;aid in the argumentation; That Conden&longs;ation | |
| <lb/>was the propriety of Cold, and there was alledged for in&longs;tance, the | |
| <lb/>example of Ice: now I at that time &longs;aid, that, in my judgment, | |
| <lb/>the Ice &longs;hould be rather Water rarified than conden&longs;ed, and my | |
| <lb/><arrow.to.target n="marg1399"></arrow.to.target> | |
| <lb/>rea&longs;on was, becau&longs;e Conden&longs;ation begets diminution of Ma&longs;s, and | |
| <lb/>augmentation of gravity, and Rarifaction cau&longs;eth greater Lightne&longs;s, | |
| <lb/>and augmentarion of Ma&longs;&longs;e: and Water in freezing, encrea&longs;eth in | |
| <lb/>Ma&longs;&longs;e, and the Ice made thereby is lighter than the Water on which | |
| <lb/>it &longs;wimmeth.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1398"></margin.target>Conden&longs;ation | |
| <lb/>the Propriety of | |
| <lb/>Cold, according | |
| <lb/>to the Peripate­ | |
| <lb/>ticks.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1399"></margin.target>Ice rather water | |
| <lb/>rarified, than | |
| <lb/>conden&longs;ed, and | |
| <lb/>why:</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>What I &longs;ay, is manife&longs;t, becau&longs;e, the medium &longs;ubtracting from the | |
| <lb/>whole Gravity of Sollids the weight of &longs;uch another Ma&longs;&longs;e of the &longs;aid<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1400"></arrow.to.target> | |
| <lb/><emph type="italics"/>Medium; was<emph.end type="italics"/> Archimedes <emph type="italics"/>proves in his ^{*} Fir&longs;t Booke<emph.end type="italics"/> De In&longs;identibus | |
| <lb/>Humido; <emph type="italics"/>when ever the Ma&longs;&longs;e of the &longs;aid Solid encrea&longs;eth by Di&longs;traction, | |
| <lb/>the more &longs;hall the<emph.end type="italics"/> Medium <emph type="italics"/>detract from its entire Gravity; and le&longs;&longs;e, | |
| <lb/>when by Compre&longs;&longs;ion it &longs;hall be conden&longs;ed and reduced to a le&longs;&longs;e Ma&longs;&longs;e.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| | |
| <pb pagenum="404"/> | |
| | |
| <s><margin.target id="marg1400"></margin.target>In lib: 1. of Na­ | |
| <lb/>tation of Bodies | |
| <lb/>Prop. </s><s>7.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1401"></margin.target>Figure operates | |
| <lb/>not in the Nata­ | |
| <lb/>tion of Sollids.</s></p><p type="main"> | |
| | |
| <s>It was an&longs;wered me, that that proceeded not from the greater Levity; | |
| <lb/><arrow.to.target n="marg1401"></arrow.to.target> | |
| <lb/>but from the Figure, large and flat, which not being able to pene­ | |
| <lb/>trate the Re&longs;i&longs;tance of the Water, is the cau&longs;e that it &longs;ubmergeth not. | |
| <lb/></s><s>I replied, that any piece of Ice, of what&longs;oever Figure, &longs;wims upon | |
| <lb/>the Water, a manife&longs;t &longs;igne, that its being never &longs;o flat and broad, | |
| <lb/>hath not any part in its floating: and added, that it was a manife&longs;t | |
| <lb/>proofe hereof to &longs;ee a piece of Ice of very broad Figure being thru&longs;t | |
| <lb/>to the botome of the Water, &longs;uddenly return to flote atoppe, which | |
| <lb/>had it been more grave, and had its &longs;wimming proceeded from its | |
| <lb/>Forme, unable to penetrate the Re&longs;i&longs;tance of the <emph type="italics"/>Medium,<emph.end type="italics"/> that | |
| <lb/>would be altogether impo&longs;&longs;ible; I concluded therefore, that the Figure | |
| <lb/>was in &longs;ort a Cau&longs;e of the Natation or Submer&longs;ion of Bodies, | |
| <lb/>but the greater or le&longs;&longs;e Gravity in re&longs;pect of the Water: and there­ | |
| <lb/>fore all Bodyes heavier than it of what Figure &longs;oever they be, indiffe­ | |
| <lb/>rently go to the bottome, and the lighter, though of any figure, float | |
| <lb/>indifferently on the top: and I &longs;uppo&longs;e that tho&longs;e which hold other­ | |
| <lb/>wi&longs;e, were induced to that beliefe, by &longs;eeing how that diver&longs;ity | |
| <lb/>of Formes or Figures, greatly altereth the Velo&longs;ity, and Tardity | |
| <lb/>of Motion; &longs;o that Bodies of Figure broad and thin, de&longs;cend | |
| <lb/>far more lea&longs;urely into the Water, than tho&longs;e of a more compacted | |
| <lb/>Figure, though both made of the &longs;ame Matter: by which &longs;ome | |
| <lb/>might be induced to believe that the Dilatation of the Figure might | |
| <lb/>reduce it to &longs;uch amplene&longs;&longs;e that it &longs;hould not only retard but wholly | |
| <lb/>impede and take away the Motion, which I hold to be fal&longs;e. </s><s>Upon | |
| <lb/>this Conclu&longs;ion, in many dayes di&longs;cour&longs;e, was &longs;poken much, and | |
| <lb/>many things, and divers Experiments produced, of which your | |
| <lb/>Highne&longs;&longs;e heard, and &longs;aw &longs;ome, and in this di&longs;cour&longs;e &longs;hall have | |
| <lb/>all that which hath been produced again&longs;t my A&longs;&longs;ertion, and what | |
| <lb/>hath been &longs;ugge&longs;ted to my thoughts on this matter, and for con­ | |
| <lb/>firmation of my Conclu&longs;ion: which if it &longs;hall &longs;uffice to remove that | |
| <lb/>(as I e&longs;teem hitherto fal&longs;e) Opinion, I &longs;hall thinke I have not | |
| <lb/>unprofitably &longs;pent my paynes and time. </s><s>and although that come | |
| <lb/>not to pa&longs;&longs;e, yet ought I to promi&longs;e another benefit to my &longs;elfe, | |
| <lb/>namely, of attaining the knowledge of the truth, by hearing my | |
| <lb/>Fallacyes confuted, and true demon&longs;trations produced by tho&longs;e | |
| <lb/>of the contrary opinion.</s></p><p type="main"> | |
| | |
| <s>And to proceed with the greate&longs;t plainne&longs;s and per&longs;picuity that | |
| <lb/>I can po&longs;&longs;ible, it is, I conceive, nece&longs;&longs;ary, fir&longs;t of all to declare | |
| <lb/>what is the true, intrin&longs;ecall, and totall Cau&longs;e, of the a&longs;cending of | |
| <lb/>&longs;ome Sollid Bodyes in the Water, and therein floating; or on the | |
| <lb/>contrary, of their &longs;inking. </s><s>and &longs;o much the rather in a&longs;much as I | |
| <lb/>cannot &longs;atisfie my &longs;elfe in that which <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> hath left written on | |
| <lb/>this Subject.</s></p><p type="margin"> | |
| <s><margin.target id="marg1402"></margin.target>The cau&longs;e of the | |
| <lb/>Natation & &longs;ub­</s></p> <p type="main"> | |
| | |
| <s>I &longs;ay then the Cau&longs;e why &longs;ome Sollid Bodyes de&longs;cend to the | |
| <lb/><arrow.to.target n="marg1402"></arrow.to.target> | |
| | |
| | |
| <pb pagenum="405"/>Bottom of Water, is the exce&longs;&longs;e of their Gravity, above the | |
| <lb/><arrow.to.target n="marg1403"></arrow.to.target> | |
| <lb/>Gravity of the Water; and on the contrary, the exce&longs;s of the | |
| <lb/>Waters Gravity above the Gravity of tho&longs;e, is the Cau&longs;e that others | |
| <lb/>do not de&longs;cend, rather that they ri&longs;e from the Bottom, and a&longs;cend | |
| <lb/>to the Surface. </s><s>This was &longs;ubtilly demon&longs;trated by <emph type="italics"/>Archimedes<emph.end type="italics"/> in | |
| <lb/>his Book Of the NATATION of BODIES: Conferred afterwards | |
| <lb/>by a very grave Author, but, if I erre not invi&longs;ibly, as below for | |
| <lb/>defence of him, I &longs;hall endeavour to prove.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1403"></margin.target>mer&longs;ion of Sol­ | |
| <lb/>ids in the Wa­ | |
| <lb/>ter.</s></p><p type="main"> | |
| | |
| <s>I, with a different Method, and by other meanes, will endeavour | |
| <lb/>to demon&longs;trate the &longs;ame, reducing the Cau&longs;es of &longs;uch Effects to | |
| <lb/>more intrin&longs;ecall and immediate Principles, in which al&longs;o are di&longs;co­ | |
| <lb/>vered the Cau&longs;es of &longs;ome admirable and almo&longs;t incredible Acci­ | |
| <lb/>dents, as that would be, that a very little quantity of Water, &longs;hould | |
| <lb/>be able, with its &longs;mall weight, to rai&longs;e and &longs;u&longs;tain a Solid Body, an | |
| <lb/>hundred or a thou&longs;and times heavier than it.</s></p><p type="main"> | |
| | |
| <s>And becau&longs;e demon&longs;trative Order &longs;o requires, I &longs;hall define cer­ | |
| <lb/>tain Termes, and afterwards explain &longs;ome Propo&longs;itions, of which, | |
| <lb/>as of things true and obvious, I may make u&longs;e of to my pre&longs;ent pur­ | |
| <lb/>po&longs;e.</s></p><p type="head"> | |
| | |
| <s>DEFINITION I.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>I then call equally Grave<emph.end type="italics"/> in &longs;pecie, <emph type="italics"/>tho&longs;e Matters | |
| <lb/>of which equall Ma&longs;&longs;es weigh equally.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>As if for example, two Balls, one of Wax, and the other of &longs;ome | |
| <lb/>Wood of equall Ma&longs;&longs;e, were al&longs;o equall in Weight, we &longs;ay, that | |
| <lb/>&longs;uch Wood, and the Wax are <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> equally grave.</s></p><p type="head"> | |
| | |
| <s>DEFINITION II.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>But equally grave in Ab&longs;olute Gravity, we call two | |
| <lb/>Sollids, weighing equally, though of Ma&longs;s they be | |
| <lb/>unequall.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>As for example, a Ma&longs;s of Lead, and another of Wood, that | |
| <lb/>weigh each ten pounds, I call equall in Ab&longs;olute Gravity, though | |
| <lb/>the Ma&longs;s of the Wood be much greater then that of the Lead.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>And, con&longs;equently, le&longs;s Grave<emph.end type="italics"/> in &longs;pecie.</s></p><p type="head"> | |
| | |
| <s>DEFINITION III.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>I call a Matter more Grave<emph.end type="italics"/> in &longs;pecie <emph type="italics"/>than another, of | |
| <lb/>which a Ma&longs;s, equall to a Ma&longs;s of the other, &longs;hall | |
| <lb/>weigh more.<emph.end type="italics"/></s></p> | |
| | |
| | |
| <pb pagenum="406"/><p type="main"> | |
| | |
| <s>And &longs;o I &longs;ay, that Lead is more grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than Tinn, becau&longs;e | |
| <lb/>if you take of them two equall Ma&longs;&longs;es, that of the Lead weigheth | |
| <lb/>more.</s></p><p type="head"> | |
| | |
| <s>DEFINITION IV.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>But I call that Body more grave ab&longs;olutely than this, if | |
| <lb/>that weigh more than this, without any re&longs;pect had to | |
| <lb/>the Ma&longs;&longs;es.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>And thus a great piece of Wood is &longs;aid to weigh more than a | |
| <lb/>little lump of Lead, though the Lead be <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> more heavy than | |
| <lb/>the Wood. </s><s>And the &longs;ame is to be under&longs;tood of the le&longs;s grave <emph type="italics"/>in | |
| <lb/>&longs;pecie,<emph.end type="italics"/> and the le&longs;s grave ab&longs;olutely.</s></p><p type="main"> | |
| | |
| <s>The&longs;e Termes defined, I take from the Mechanicks two Princi­ | |
| <lb/>ples: the fir&longs;t is, that</s></p><p type="head"> | |
| | |
| <s>AXIOME. I.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Weights ab&longs;olutely equall, moved with equall Velocity, | |
| <lb/>are of equall Force and Moment in their operations.<emph.end type="italics"/></s></p><p type="head"> | |
| | |
| <s><emph type="italics"/>DEFINITION V.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>Moment, among&longs;t Mechanicians, &longs;igrifieth that | |
| <lb/>Vertue, that Force, or that Efficacy, with which | |
| <lb/>the Mover moves, and the Moveable re&longs;i&longs;ts.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Which Vertue dependes not only on the &longs;imple Gravity, but on the | |
| <lb/>Velocity of the Motion, and on the diver&longs;e Inclinations of the Spaces | |
| <lb/>along which the Motion is made: For a de&longs;cending Weight makes a | |
| <lb/>greater<emph.end type="italics"/> Impetus <emph type="italics"/>in a Space much declining, than in one le&longs;s declining; | |
| <lb/>and in &longs;umme, what ever is the occa&longs;ion of &longs;uch Vertue, it ever retaines | |
| <lb/>the name of<emph.end type="italics"/> Moment; <emph type="italics"/>nor in my Judgement, is this &longs;ence new in our | |
| <lb/>Idiome, for, if I mistake not, I think we often &longs;ay; This is a weighty | |
| <lb/>bu&longs;ine&longs;&longs;e, but the other is of &longs;mall moment: and we con&longs;ider lighter mat­ | |
| <lb/>ters and let pa&longs;s tho&longs;e of Moment; a Metaphor, I &longs;uppo&longs;e, taken from | |
| <lb/>the Mechanicks.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>As for example, two weights equall in ab&longs;olute Gravity, being | |
| <lb/>put into a Ballance of equall Arms, they &longs;tand in <emph type="italics"/>Equilibrium,<emph.end type="italics"/> nei­ | |
| <lb/>ther one going down, nor the other up: becau&longs;e the equality of the | |
| <lb/>Di&longs;tances of both, from the Centre on which the Ballance is &longs;uppor­ | |
| <lb/>ted, and about which it moves, cau&longs;eth that tho&longs;e weights, the &longs;aid | |
| <lb/>Ballance moving, &longs;hall in the &longs;ame Time move equall Spaces, that is, | |
| <lb/>&longs;hall move with equall Velocity, &longs;o that there is no rea&longs;on for which | |
| | |
| | |
| <pb pagenum="407"/>this Weight &longs;hould de&longs;cend more than that, or that more than this; | |
| <lb/>and therefore they make an <emph type="italics"/>Equilibrium,<emph.end type="italics"/> and their Moments continue | |
| <lb/>of &longs;emblable and equall Vertue.</s></p><p type="main"> | |
| | |
| <s>The &longs;econd Principle is; That</s></p><p type="head"> | |
| | |
| <s>AXIOME II.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>The Moment and Force of the Gravity, is encrea&longs;ed by | |
| <lb/>the Velocity of the Motion.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>So that Weights ab&longs;olutely equall, but conjoyned with Velocity | |
| <lb/>unequall, are of Force, Moment and Vertue unequall: and the | |
| <lb/>more potent, the more &longs;wift, according to the proportion of the Ve­ | |
| <lb/>locity of the one, to the Velocity of the other. </s><s>Of this we have a | |
| <lb/>very pertinent example in the Balance or Stiliard of unequall Arms, | |
| <lb/>at which Weights ab&longs;olutely equall being &longs;u&longs;pended, they do not | |
| <lb/>weigh down, and gravitate equally, but that which is at a greater | |
| <lb/>di&longs;tance from the Centre, about which the Beam moves, de&longs;cends, | |
| <lb/>rai&longs;ing the other, and the Motion of this which a&longs;cends is &longs;low, and | |
| <lb/>the other &longs;wift: and &longs;uch is the Force and Vertue, which from the | |
| <lb/>Velocity of the Mover, is conferred on the Moveable, which receives | |
| <lb/>it, that it can exqui&longs;itely compen&longs;ate, as much more Weight added to | |
| <lb/>the other &longs;lower Moveable: &longs;o that if of the Arms of the Balance, | |
| <lb/>one were ten times as long as the other, whereupon in the Beames | |
| <lb/>moving about the Centre, the end of that would go ten times as far | |
| <lb/>as the end of this, a Weight &longs;u&longs;pended at the greater di&longs;tance, may | |
| <lb/>&longs;u&longs;tain and poy&longs;e another ten times more grave ab&longs;olutely than it: | |
| <lb/>and that becau&longs;e the Stiliard moving, the le&longs;&longs;er Weight &longs;hall move | |
| <lb/>ten times fa&longs;ter than the bigger. </s><s>It ought alwayes therefore to be | |
| <lb/>under&longs;tood, that Motions are according to the &longs;ame Inclinations, | |
| <lb/>namely, that if one of the Moveables move perpendicularly to the | |
| <lb/>Horizon, then the other makes its Motion by the like Perpendicular; | |
| <lb/>and if the Motion of one were to be made Horizontally; that then | |
| <lb/>the other is made along the &longs;ame Horizontall plain: and in &longs;umme, | |
| <lb/>alwayes both in like Inclinations. </s><s>This proportion between the | |
| <lb/>Gravity and Velocity is found in all Mechanicall In&longs;truments: and | |
| <lb/>is con&longs;idered by <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> as a Principle in his <emph type="italics"/>Mechanicall Que&longs;tions<emph.end type="italics"/>; | |
| <lb/>whereupon we al&longs;o may take it for a true A&longs;&longs;umption, That</s></p><p type="head"> | |
| | |
| <s>AXIOME III.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Weights ab&longs;olutely unequall, do alternately counterpoy&longs;e | |
| <lb/>and become of equall Moments, as oft as their Gravi­ | |
| <lb/>ties, with contrary proportion, an&longs;wer to the Velocity of | |
| <lb/>their Motions.<emph.end type="italics"/></s></p> | |
| | |
| | |
| <pb pagenum="408"/><p type="main"> | |
| | |
| <s>That is to &longs;ay, that by how much the one is le&longs;s grave than the other, | |
| <lb/>by &longs;o much is it in a con&longs;titution of moving more &longs;wiftly than that.</s></p><p type="main"> | |
| | |
| <s>Having prefatically explicated the&longs;e things, we may begin to en­ | |
| <lb/>quire, what Bodyes tho&longs;e are which totally &longs;ubmerge in Water, and | |
| <lb/>go to the Bottom, and which tho&longs;e that by con&longs;traint float on the | |
| <lb/>top, &longs;o that being thru&longs;t by violence under Water, they return to | |
| <lb/>&longs;wim, with one part of their Ma&longs;s vi&longs;ible above the Surface of the | |
| <lb/>Water: and this we will do by con&longs;idering the re&longs;pective operati­ | |
| <lb/>on of the &longs;aid Solids, and of Water: Which operation followes | |
| <lb/>the Submer&longs;ion and &longs;inking; and this it is, That in the Submer&longs;ion | |
| <lb/><arrow.to.target n="marg1404"></arrow.to.target> | |
| <lb/>that the Solid maketh, being depre&longs;&longs;ed downwards by its proper | |
| <lb/>Gravity, it comes to drive away the water from the place where it | |
| <lb/>&longs;ucce&longs;&longs;ively &longs;ubenters, and the water repul&longs;ed ri&longs;eth and a&longs;cends | |
| <lb/>above its fir&longs;t levell, to which A&longs;cent on the other &longs;ide it, as being a | |
| <lb/>grave Body of its own nature, re&longs;i&longs;ts: And becau&longs;e the de&longs;cending | |
| <lb/>Solid more and more immerging, greater and greater quantity of | |
| <lb/>Water a&longs;cends, till the whole Sollid be &longs;ubmerged; its nece&longs;&longs;ary to | |
| <lb/>compare the Moments of the Re&longs;i&longs;tance of the water to A&longs;cen&longs;ion, | |
| <lb/>with the Moments of the pre&longs;&longs;ive Gravity of the Solid: And if the | |
| <lb/>Moments of the Re&longs;i&longs;tance of the water, &longs;hall equalize the Moments | |
| <lb/><arrow.to.target n="marg1405"></arrow.to.target> | |
| <lb/>of the Solid, before its totall Immer&longs;ion; in this ca&longs;e doubtle&longs;s there | |
| <lb/>&longs;hall be made an <emph type="italics"/>Equilibrium,<emph.end type="italics"/> nor &longs;hall the Body &longs;ink any farther. | |
| <lb/></s><s>But if the Moment of the Solid, &longs;hall alwayes exceed the Moments | |
| <lb/><arrow.to.target n="marg1406"></arrow.to.target> | |
| <lb/>wherewith the repul&longs;ed water &longs;ucce&longs;&longs;ively makes Re&longs;i&longs;tance, that | |
| <lb/>Solid &longs;hall not only wholly &longs;ubmerge under water, but &longs;hall de&longs;cend | |
| <lb/>to the Bottom. </s><s>But if, la&longs;tly, in the in&longs;tant of totall Submer&longs;ion, | |
| <lb/><arrow.to.target n="marg1407"></arrow.to.target> | |
| <lb/>the equality &longs;hall be made between the Moments of the prement | |
| <lb/>Solid, and the re&longs;i&longs;ting Water; then &longs;hall re&longs;t en&longs;ue, and the &longs;aid | |
| <lb/>Solid &longs;hall be able to re&longs;t indifferently, in what&longs;oever part of the | |
| <lb/>water. </s><s>By this time is manife&longs;t the nece&longs;&longs;ity of comparing the | |
| <lb/><arrow.to.target n="marg1408"></arrow.to.target> | |
| <lb/>Gravity of the water, and of the Solid; and this compari&longs;on might | |
| <lb/>at fir&longs;t &longs;ight &longs;eem &longs;ufficient to conclude and determine which are the | |
| <lb/>Solids that float a-top, and which tho&longs;e that &longs;ink to the Bottom in the | |
| <lb/>water, a&longs;&longs;erting that tho&longs;e &longs;hall float which are le&longs;&longs;e grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> | |
| <lb/>than the water, and tho&longs;e &longs;ubmerge, which are <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> more grave. | |
| <lb/></s><s>For it &longs;eems in appearance, that the Sollid in &longs;inking continually, | |
| <lb/>rai&longs;eth &longs;o much Water in Ma&longs;s, as an&longs;wers to the parts of its own | |
| <lb/>Bulk &longs;ubmerged: whereupon it is impo&longs;&longs;ible, that a Solid le&longs;s grave | |
| <lb/><emph type="italics"/>in &longs;pecie,<emph.end type="italics"/> than water, &longs;hould wholly &longs;ink, as being unable to rai&longs;e a | |
| <lb/>weight greater than its own, and &longs;uch would a Ma&longs;s of water equall | |
| <lb/>to its own Ma&longs;s be. </s><s>And likewi&longs;e it &longs;eems nece&longs;&longs;ary, that the graver | |
| <lb/>Solids do go to the Bottom, as being of a Force more than &longs;ufficient | |
| <lb/>for the rai&longs;ing a Ma&longs;&longs;e of water, equall to its own, though inferiour | |
| <lb/>in weight. </s><s>Neverthele&longs;s the bu&longs;ine&longs;s &longs;ucceeds otherwi&longs;e: and | |
| | |
| | |
| <pb pagenum="409"/>though the Conclu&longs;ions are true, yet are the Cau&longs;es thus a&longs;&longs;igned | |
| <lb/>deficient, nor is it true, that the Solid in &longs;ubmerging, rai&longs;eth and | |
| <lb/>repul&longs;eth Ma&longs;&longs;es of Water, equall to the parts of it &longs;elf &longs;ubmerged; | |
| <lb/>but the Water repul&longs;ed, is alwayes le&longs;s than the parts of the Solid | |
| <lb/><arrow.to.target n="marg1409"></arrow.to.target> | |
| <lb/>&longs;ubmerged: and &longs;o much the more by how much the Ve&longs;&longs;ell in | |
| <lb/>which the Water is contained is narrower: in &longs;uch manner that it | |
| <lb/>hinders not, but that a Solid may &longs;ubmerge all under Water, with­ | |
| <lb/>out rai&longs;ing &longs;o much Water in Ma&longs;s, as would equall the tenth or | |
| <lb/>twentieth part of its own Bulk: like as on the contrary, a very | |
| <lb/><arrow.to.target n="marg1410"></arrow.to.target> | |
| <lb/>&longs;mall quantity of Water, may rai&longs;e a very great Solid Ma&longs;s, though | |
| <lb/>&longs;uch Solid &longs;hould weigh ab&longs;olutely a hundred times as much, or | |
| <lb/>more, than the &longs;aid Water, if &longs;o be that the Matter of that &longs;ame | |
| <lb/>Solid be <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> le&longs;s grave than the Water. </s><s>And thus a great | |
| <lb/>Beam, as &longs;uppo&longs;e of a 1000 weight, may be rai&longs;ed and born afloat | |
| <lb/>by Water, which weighs not 50: and this happens when the Mo­ | |
| <lb/>ment of the Water is compen&longs;ated by the Velocity of its Motion.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1404"></margin.target>How the &longs;ub­ | |
| <lb/>mer&longs;ion of So­ | |
| <lb/>lids in the Wa­ | |
| <lb/>ter, is effected.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1405"></margin.target>What Solids | |
| <lb/>&longs;hall float on the | |
| <lb/>Water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1406"></margin.target>What Solids | |
| <lb/>&longs;hall &longs;inke to the | |
| <lb/>botome.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1407"></margin.target>What Solids | |
| <lb/>&longs;hall re&longs;t in all | |
| <lb/>places of the Wa­ | |
| <lb/>ter.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1408"></margin.target>The Gravitie of | |
| <lb/>the Water and | |
| <lb/><emph type="italics"/>S<emph.end type="italics"/>olid mu&longs;t be | |
| <lb/>compared in all | |
| <lb/>Problems, of Na­ | |
| <lb/>tation of Bodies.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1409"></margin.target>The water re­ | |
| <lb/>pul&longs;ed is ever le&longs;s | |
| <lb/>than the parts of | |
| <lb/>the Sollid &longs;ub­ | |
| <lb/>merged.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1410"></margin.target><emph type="italics"/>A<emph.end type="italics"/> &longs;mall quantity | |
| <lb/>of water, may | |
| <lb/>float a very | |
| <lb/>great Solid Ma&longs;s.</s></p><p type="main"> | |
| | |
| <s>But becau&longs;e &longs;uch things, propounded thus in ab&longs;tract, are &longs;ome­ | |
| <lb/>what difficult to be comprehended, it would be good to demon&longs;trate | |
| <lb/>them by particular examples; and for facility of demon&longs;tration, we | |
| <lb/>will &longs;uppo&longs;e the Ve&longs;&longs;els in which we are to put the Water, and place | |
| <lb/>the Solids, to be inviron'd and included with &longs;ides erected perpendi­ | |
| <lb/>cular to the Plane of the Horizon, and the Solid that is to be put | |
| <lb/>into &longs;uch ve&longs;&longs;ell to be either a &longs;treight Cylinder, or el&longs;e an upright | |
| <lb/>Pri&longs;me</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>The which propo&longs;ed and declared, I proceed to demonstrate the truth | |
| <lb/>of what hath been hinted, forming the en&longs;uing Theoreme.<emph.end type="italics"/></s></p><p type="head"> | |
| | |
| <s><emph type="italics"/>THEOREME I.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>The Ma&longs;s of the Water whicha&longs;cends in the &longs;ub­ | |
| <lb/><arrow.to.target n="marg1411"></arrow.to.target> | |
| <lb/>merging of a Solid, Pri&longs;me or Cylinder, or that | |
| <lb/>aba&longs;eth in taking it out, is le&longs;s than the Ma&longs;s of | |
| <lb/>the &longs;aid Solid, &longs;o depre&longs;&longs;ed or advanced: and | |
| <lb/>hath to it the &longs;ame proportion, that the Surface | |
| <lb/>of the Water circumfu&longs;ing the Solid, hath to the | |
| <lb/>&longs;ame circumfu&longs;ed Surface, together with the Ba&longs;e | |
| <lb/>of the Solid.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1411"></margin.target><emph type="italics"/>T<emph.end type="italics"/>he Proportion | |
| <lb/>of the water rai­ | |
| <lb/>&longs;ed to the <emph type="italics"/>S<emph.end type="italics"/>olid | |
| <lb/>&longs;ubmerged.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Let the Ve&longs;&longs;ell be A B C D, and in it the Water rai&longs;ed up to the | |
| <lb/>Levell E F G, before the Solid Pri&longs;me H I K be therein immerged; | |
| <lb/>but after that it is depre&longs;&longs;ed under Water, let the Water be rai&longs;ed as | |
| <lb/>high as the Levell L M, the Solid H I K &longs;hall then be all under Water, | |
| <lb/>and the Ma&longs;s of the elevated Water &longs;hall be L G, which is le&longs;s than the<emph.end type="italics"/> | |
| | |
| | |
| <pb pagenum="410"/><figure id="fig262"></figure> | |
| <lb/><emph type="italics"/>Ma&longs;&longs;e of the Solid depre&longs;&longs;ed, namely of | |
| <lb/>H I K, being equall to the only part E I K, | |
| <lb/>which is contained under the fir&longs;t Levell | |
| <lb/>E F G. </s><s>Which is manife&longs;t, becau&longs;e if | |
| <lb/>the Solid H I K be taken out, the Water | |
| <lb/>I G &longs;hall return into the place occupied by | |
| <lb/>the Ma&longs;s E I K, where it was continuate be­ | |
| <lb/>fore the &longs;ubmer&longs;ion of the Pri&longs;me. </s><s>And | |
| <lb/>the Ma&longs;s L G being equall to the Ma&longs;s | |
| <lb/>E K: adde thereto the Ma&longs;s E N, and it | |
| <lb/>&longs;hall be the whole Ma&longs;s E M, compo&longs;ed of the parts of the Pri&longs;me E N, | |
| <lb/>and of the Water N F, equall to the whole Solid H I K: And, there­ | |
| <lb/>fore, the Ma&longs;s L G &longs;hall have the &longs;ame proportion to E M, as to the | |
| <lb/>Ma&longs;s H I K: But the Ma&longs;s L G hath the &longs;ame proportion to the Ma&longs;s | |
| <lb/>E M, as the Surface L M hath to the Surface M H: Therefore it is ma­ | |
| <lb/>nife&longs;t, that the Ma&longs;s of Water repul&longs;ed L G, is in proportion to the Ma&longs;s | |
| <lb/>of the Solid &longs;ubmerged H I K; as the Surface L M, namely, that of the | |
| <lb/>Water ambient about the Sollid, to the whole Surface H M, compounded | |
| <lb/>of the &longs;aid ambient water, and the Ba&longs;e of the Pri&longs;me H N. </s><s>But if we | |
| <lb/>&longs;uppo&longs;e the fir&longs;t Levell of the Water the according to the Surface H M, | |
| <lb/>and the Pri&longs;me allready &longs;ubmerged H I K; and after to be taken out and | |
| <lb/>rai&longs;ed to E A O, and the Water to be faln from the fir&longs;t Levell H L M as | |
| <lb/>low as E F G; It is manife&longs;t, that the Pri&longs;me E A O being the &longs;ame with | |
| <lb/>H I K, its &longs;uperiour part H O, &longs;hall be equall to the inferiour E I K: | |
| <lb/>and remove the common part E N, and, con&longs;equently, the Ma&longs;s of the | |
| <lb/>Water L G is equall to the Ma&longs;s H O; and, therefore, le&longs;s than the | |
| <lb/>Solid, which is without the Water, namely, the whole Pri&longs;me E A O, to | |
| <lb/>which likewi&longs;e, the &longs;aid Ma&longs;s of Water abated L G, hath the &longs;ame propor­ | |
| <lb/>tion, that the Surface of the Waters circumfu&longs;ed L M hath to the &longs;ame | |
| <lb/>circumfu&longs;ed Surface, together with the Ba&longs;e of the Pri&longs;me A O: which | |
| <lb/>hath the &longs;ame demon&longs;tration with the former ca&longs;e above.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>And from hence is inferred, that the Ma&longs;s of the Water, that ri&longs;eth in | |
| <lb/>the immer&longs;ion of the Solid, or that ebbeth in elevating it, is not equall to | |
| <lb/>all the Ma&longs;s of the Solid, which is &longs;ubmerged or elevated, but to that | |
| <lb/>part only, which in the immer&longs;ion is under the fir&longs;t Levell of the Water, | |
| <lb/>and in the elevation remaines above the fir&longs;t Levell: Which is that | |
| <lb/>which was to be demon&longs;trated. </s><s>We will now pur&longs;ue the things that | |
| <lb/>remain.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>And fir&longs;t we will demon&longs;trate that,</s></p> | |
| | |
| | |
| <pb pagenum="411"/><p type="head"> | |
| | |
| <s>THEOREME II.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>When in one of the above &longs;aid Ve&longs;&longs;els, of what ever<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1412"></arrow.to.target> | |
| <lb/><emph type="italics"/>breadth, whether wide or narrow, there is placed &longs;uch | |
| <lb/>a Pri&longs;me or Cylinder, inviron'd with Water, if we ele­ | |
| <lb/>vate that Solid perpendicularly, the Water circumfu­ | |
| <lb/>&longs;ed &longs;hall abate, and the Abatement of the Water, | |
| <lb/>&longs;hall have the &longs;ame proportion to the Elevation of the | |
| <lb/>Pri&longs;me, as one of the Ba&longs;es of the Pri&longs;me, hath to | |
| <lb/>the Surface of the Water Circumfu&longs;ed.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1412"></margin.target>The proportion | |
| <lb/>of the water aba­ | |
| <lb/>ted, to the Solid | |
| <lb/>rai&longs;ed.</s></p><p type="main"> | |
| | |
| <s>Imagine in the Ve&longs;&longs;ell, as is afore&longs;aid, the | |
| <lb/><figure id="fig263"></figure> | |
| <lb/>Pri&longs;me A C D B to be placed, and in the | |
| <lb/>re&longs;t of the Space the Water to be dif­ | |
| <lb/>fu&longs;ed as far as the Levell E A: and rai­ | |
| <lb/>&longs;ing the Solid, let it be transferred to | |
| <lb/>G M, and let the Water be aba&longs;ed from | |
| <lb/>E A to N O: I &longs;ay, that the de&longs;cent of | |
| <lb/>the Water, mea&longs;ured by the Line A O, | |
| <lb/>hath the &longs;ame proportion to the ri&longs;e of the | |
| <lb/>Pri&longs;me, mea&longs;ured by the Line G A, as the Ba&longs;e of the Solid G H | |
| <lb/>hath to the Surface of the Water N O. </s><s>The which is manife&longs;t: | |
| <lb/>becau&longs;e the Ma&longs;s of the Solid G A B H, rai&longs;ed above the fir&longs;t Levell | |
| <lb/>E A B, is equall to the Ma&longs;s of Water that is aba&longs;ed E N O A. | |
| <lb/>Therefore, E N O A and G A B H are two equall Pri&longs;mes; for of | |
| <lb/>equall Pri&longs;mes, the Ba&longs;es an&longs;wer contrarily to their heights: There­ | |
| <lb/>fore, as the Altitude A O is to the Altitude A G, &longs;o is the Superfi­ | |
| <lb/>cies or Ba&longs;e G H to the Surface of the Water N O. </s><s>If therefore, | |
| <lb/>for example, a Pillar were erected in a wa&longs;te Pond full of Water, | |
| <lb/>or el&longs;e in a Well, capable of little more then the Ma&longs;s of the &longs;aid | |
| <lb/>Pillar, in elevating the &longs;aid Pillar, and taking it out of the Water, | |
| <lb/>according as it ri&longs;eth, the Water that invirons it will gradually abate, | |
| <lb/>and the aba&longs;ement of the Water at the in&longs;tant of lifting out the | |
| <lb/>Pillar, &longs;hall have the &longs;ame proportion, that the thickne&longs;s of the Pillar | |
| <lb/>hath to the exce&longs;s of the breadth of the &longs;aid Pond or Well, above | |
| <lb/>the thickne&longs;s of the &longs;aid Pillar: &longs;o that if the breadth of the Well | |
| <lb/>were an eighth part larger than the thickne&longs;s of the Pillar, and the | |
| <lb/><arrow.to.target n="marg1413"></arrow.to.target> | |
| <lb/>breadth of the Pond twenty five times as great as the &longs;aid thickne&longs;s, | |
| <lb/>in the Pillars a&longs;cending one foot, the water in the Well &longs;hall de&longs;cend | |
| <lb/>&longs;even foot, and that in the Pond only 1/25 of a foot.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1413"></margin.target>Why a Solid | |
| <lb/>le&longs;s grave <emph type="italics"/>in &longs;pe­ | |
| <lb/>cie<emph.end type="italics"/> than water, | |
| <lb/>&longs;tayeth not un­ | |
| <lb/>der water, in ve­ | |
| <lb/>ry &longs;mall depthst.</s></p><p type="main"> | |
| | |
| <s>This Demon&longs;trated, it will not be difficult to &longs;hew the true | |
| <lb/>cau&longs;e, how it comes to pa&longs;s, that,</s></p> | |
| | |
| | |
| <pb pagenum="412"/><p type="head"> | |
| | |
| <s>THEOREME III.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>A Pri&longs;me or regular Cylinder, of a &longs;ub&longs;tance &longs;pecifically | |
| <lb/>le&longs;s grave than Water, if it &longs;hould be totally &longs;ubmerged | |
| <lb/>in Water, &longs;tayes not underneath, but ri&longs;eth, though the | |
| <lb/>Water circumfu&longs;ed be very little, and in ab&longs;olute | |
| <lb/>Gravity, never &longs;o much inferiour to the Gravity of the | |
| <lb/>&longs;aid Pri&longs;me.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>Let then the Pri&longs;me A E F B, be put into the Ve&longs;&longs;ell C D F B, the | |
| <lb/>&longs;ame being le&longs;s grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than the Water: and let the | |
| <lb/>Water infu&longs;ed ri&longs;e to the height of the Pri&longs;me: I &longs;ay, that the | |
| <lb/>Pri&longs;me left at liberty, it &longs;hall ri&longs;e, being born up | |
| <lb/>by the Water circumfu&longs;ed C D E A. </s><s>For the | |
| <lb/><figure id="fig264"></figure> | |
| <lb/>Water C E being &longs;pecifically more grave than | |
| <lb/>the Solid A F, the ab&longs;olute weight of the water | |
| <lb/>C E, &longs;hall have greater proportion to the ab&longs;o­ | |
| <lb/>lute weight of the Pri&longs;me A F, than the Ma&longs;s | |
| <lb/>C E hath to the Ma&longs;s A F (in regard the Ma&longs;s | |
| <lb/>hath the &longs;ame proportion to the Ma&longs;s, that the | |
| <lb/>weight ab&longs;olute hath to the weight ab&longs;olute, | |
| <lb/>in ca&longs;e the Ma&longs;&longs;es are of the &longs;ame Gravity <emph type="italics"/>in &longs;pecie.<emph.end type="italics"/>) But | |
| <lb/>the Ma&longs;s C E is to the Ma&longs;s A F, as the Surface of the water A C, is | |
| <lb/>to the Superficies, or Ba&longs;e of the Pri&longs;me A B; which is the &longs;ame pro­ | |
| <lb/>portion as the a&longs;cent of the Pri&longs;me when it ri&longs;eth, hath to the de&longs;cent | |
| <lb/>of the water circumfu&longs;ed C E.</s></p><p type="main"> | |
| | |
| <s>Therefore, the ab&longs;olute Gravity of the water C E, hath greater | |
| <lb/>proportion to the ab&longs;olute Gravity of the Pri&longs;me A F; than the | |
| <lb/>A&longs;cent of the Pri&longs;me A F, hath to the de&longs;cent of the &longs;aid | |
| <lb/>water C E. </s><s>The Moment, therefore, compounded of the ab&longs;olute | |
| <lb/>Gravity of the water C E, and of the Velocity of its de&longs;cent, whil&longs;t | |
| <lb/>it forceably repul&longs;eth and rai&longs;eth the Solid A F, is greater than the | |
| <lb/>Moment compounded of the ab&longs;olute Gravity of the Pri&longs;me A F, and | |
| <lb/>of the Tardity of its a&longs;cent, with which Moment it contra&longs;ts and re­ | |
| <lb/>fi&longs;ts the repul&longs;e and violence done it by the Moment of the water: | |
| <lb/>Therefore, the Pri&longs;me &longs;hall be rai&longs;ed. | |
| <lb/><arrow.to.target n="marg1414"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1414"></margin.target>The Proportion | |
| <lb/>according to | |
| <lb/>which the Sub­ | |
| <lb/>mer&longs;ion & Na | |
| <lb/>tation of Solids | |
| <lb/>is made.</s></p><p type="main"> | |
| | |
| <s>It followes, now, that we proceed forward to demon&longs;trate more | |
| <lb/>particularly, how much &longs;uch Solids &longs;hall be inferiour in Gravity to | |
| <lb/>the water elevated; namely, what part of them &longs;hall re&longs;t &longs;ubmerged, | |
| <lb/>and what &longs;hall be vi&longs;ible above the Surface of the water: but fir&longs;t | |
| <lb/>it is nece&longs;&longs;ary to demon&longs;trate the &longs;ub&longs;equent Lemma.</s></p> | |
| | |
| | |
| <pb pagenum="413"/><p type="head"> | |
| | |
| <s>LEMMA I.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>The ab&longs;olute Gravities of Solids, have a proportion com-<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1415"></arrow.to.target> | |
| <lb/><emph type="italics"/>pounded of the proportions of their &longs;pecificall Gravities, | |
| <lb/>and of their Ma&longs;&longs;es.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1415"></margin.target>The ab&longs;olute | |
| <lb/>Gravity of So­ | |
| <lb/>lids, are in a pro­ | |
| <lb/>portion com­ | |
| <lb/>pounded of their | |
| <lb/>Specifick Gravi­ | |
| <lb/>ties, and of their | |
| <lb/>Ma&longs;&longs;es.</s></p><p type="main"> | |
| | |
| <s>Let A and B be two Solids. </s><s>I &longs;ay, that the Ab&longs;olute Gravity | |
| <lb/>of A, hath to the Ab&longs;olute Gravity of B, a proportion com­ | |
| <lb/>pounded of the proportions of the &longs;pecificall Gravity of A, to | |
| <lb/>the Specificall Gravity of B, and of the Ma&longs;s | |
| <lb/>A to the Ma&longs;s B. </s><s>Let the Line D have the | |
| <lb/><figure id="fig265"></figure> | |
| <lb/>&longs;ame proportion to E, that the &longs;pecifick | |
| <lb/>Gravity of A, hath to the &longs;pecifick Gravity | |
| <lb/>of B; and let E be to F, as the Ma&longs;s A to the | |
| <lb/>Ma&longs;s B: It is manife&longs;t, that the proportion | |
| <lb/>of D to F, is compounded of the proportions | |
| <lb/>D and E; and E and F. </s><s>It is requi&longs;ite, | |
| <lb/>therefore, to demon&longs;trate, that as D is to F, &longs;o the ab&longs;olute Gravity | |
| <lb/>of A, is to the ab&longs;olute Gravity of B. </s><s>Take the Solid C, equall in | |
| <lb/>Ma&longs;s to the Solid A, and of the &longs;ame Gravity <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> with the Solid | |
| <lb/>B. Becau&longs;e, therefore, A and C are equall in Ma&longs;s, the ab&longs;olute | |
| <lb/>Gravity of A, &longs;hall have to the ab&longs;olute Gravity of C, the &longs;ame pro­ | |
| <lb/>portion, as the &longs;pecificall Gravity of A, hath to the &longs;pecificall Gravity | |
| <lb/>of C, or of B, which is the &longs;ame <emph type="italics"/>in &longs;pecie<emph.end type="italics"/>; that is, as D is to E. And, be­ | |
| <lb/>cau&longs;e, C and B are of the &longs;ame Gravity <emph type="italics"/>in &longs;pecie,<emph.end type="italics"/> it &longs;hall be, that as | |
| <lb/>the ab&longs;olute weight of C, is to the ab&longs;olute weight of B, &longs;o the Ma&longs;s | |
| <lb/>C, or the Ma&longs;s A, is to the Ma&longs;s B; that is, as the Line E to the Line | |
| <lb/>F. </s><s>As therefore, the ab&longs;olute Gravity of A, is to the ab&longs;olute | |
| <lb/>Gravity of C, &longs;o is the Line D to the Line E: and, as the ab&longs;olute | |
| <lb/>Gravity of C, is to the ab&longs;olute Gravity of B, &longs;o is the Line E to the | |
| <lb/>Line F: Therefore, by Equality of proportion, the ab&longs;olute Gra­ | |
| <lb/>vity of A, is to the ab&longs;olute Gravity of B, as the Line D to the | |
| <lb/>Line F: which was to be demon&longs;trated. </s><s>I proceed now to demon­ | |
| <lb/>&longs;trate, how that,</s></p> | |
| | |
| | |
| <pb pagenum="414"/><p type="head"> | |
| | |
| <s>THEOREME IV. | |
| <lb/><arrow.to.target n="marg1416"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1416"></margin.target>The proportion | |
| <lb/>of water requi­ | |
| <lb/>&longs;ite to make a | |
| <lb/>Solid &longs;wim.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>If a Solid, Cylinder, or Pri&longs;me, le&longs;&longs;e grave &longs;pecifically | |
| <lb/>than the Water, being put into a Ve&longs;&longs;el, as above, of | |
| <lb/>what&longs;oever greatne&longs;&longs;e, and the Water, be afterwards | |
| <lb/>infu&longs;ed, the Solid &longs;hall re&longs;t in the bottom, unrai&longs;ed, till | |
| <lb/>the Water arrive to that part of the Altitude, of the | |
| <lb/>&longs;aid Pri&longs;me, to which its whole Altitude hath the | |
| <lb/>&longs;ame proportion, that the Specificall Gravity of the | |
| <lb/>Water, hath to the Specificall Gravity of the &longs;aid | |
| <lb/>Solid: but infu&longs;ing more Water, the Solid &longs;hall a&longs;cend.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>Let the Ve&longs;&longs;ell be M L G N of any bigne&longs;s, and let there be pla­ | |
| <lb/>ced in it the Solid Pri&longs;me D F G E, le&longs;s grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than the | |
| <lb/>water; and look what proportion the <emph type="italics"/>S<emph.end type="italics"/>pecificall Gravity of | |
| <lb/>the water, hath to that of the Pri&longs;me, &longs;uch let the Altitude D F, have | |
| <lb/>to the Altitude F B. </s><s>I &longs;ay, that infu&longs;ing water to the Altitude F B, | |
| <lb/>the Solid D G &longs;hall not float, but &longs;hall &longs;tand in <emph type="italics"/>Equilibrium,<emph.end type="italics"/> &longs;o, that | |
| <lb/>that every little quantity of water, that is infu&longs;ed, &longs;hall rai&longs;e it. </s><s>Let | |
| <lb/>the water, therefore, be infu&longs;ed to the Levell A B C, and, becau&longs;e | |
| <lb/>the Specifick Gravity of the Solid D G, is to the Specifick Gravity of | |
| <lb/>the water, as the altitude B F is to the altitude F D; that is, as the Ma&longs;s | |
| <lb/>B G to the Ma&longs;s G D; as the proportion of the Ma&longs;s B G is to the | |
| <lb/>Ma&longs;s G D, as the proportion of the Ma&longs;s G D is to the Ma&longs;s A F, they | |
| <lb/>compo&longs;e the Proportion of the Ma&longs;s B G to the Ma&longs;s A F. Therefore, | |
| <lb/>the Ma&longs;s B G is to the Ma&longs;s A F, in a proportion compounded of the | |
| <lb/>proportions of the Specifick Gravity of the Solid G D, to the Speci­ | |
| <lb/>fick Gravity of the water, and of the Ma&longs;s G D | |
| <lb/>to the Ma&longs;s A F: But the &longs;ame proportions | |
| <lb/><figure id="fig266"></figure> | |
| <lb/>of the Specifick Gravity of G D, to the Specifick | |
| <lb/>Gravity of the water, and of the Ma&longs;s G D to | |
| <lb/>the Ma&longs;s A F, do al&longs;o by the precedent <emph type="italics"/>Lemma,<emph.end type="italics"/> | |
| <lb/>compound the proportion of the ab&longs;olute Gra­ | |
| <lb/>vity of the Solid D G, to the ab&longs;olute Gravity | |
| <lb/>of the Ma&longs;s of the water A F: Therefore, | |
| <lb/>as the Ma&longs;s B G is to the Ma&longs;s A F, &longs;o is the | |
| <lb/>Ab&longs;olute Gravity of the Solid D G, to the Ab­ | |
| <lb/>&longs;olute Gravity of the Ma&longs;s of the water A F. </s><s>But as the Ma&longs;s B G | |
| <lb/>is to the Ma&longs;s A F; &longs;o is the Ba&longs;e of the Pri&longs;me D E, to the Surface | |
| <lb/>of the water AB; and &longs;o is the de&longs;cent of the water A B, to the | |
| <lb/>Elevation of the Pri&longs;me D G; Therefore, the de&longs;cent of the | |
| | |
| | |
| <pb pagenum="415"/>water is to the elevation of the Pri&longs;me, as the ab&longs;olute Gravity of | |
| <lb/>the Pri&longs;me, is to the ab&longs;olute Gravity of the water: Therefore, the | |
| <lb/>Moment re&longs;ulting from the ab&longs;olute Gravity of the water A F, and | |
| <lb/>the Velocity of the Motion of declination, with which Moment it | |
| <lb/>forceth the Pri&longs;me D G, to ri&longs;e and a&longs;cend, is equall to the Moment | |
| <lb/>that re&longs;ults from the ab&longs;olute Gravity of the Pri&longs;me D G, and from | |
| <lb/>the Velocity of the Motion, wherewith being rai&longs;ed, it would a&longs;cend: | |
| <lb/>with which Moment it re&longs;i&longs;ts its being rai&longs;ed: becau&longs;e, therefore, | |
| <lb/>&longs;uch Moments are equall, there &longs;hall be an <emph type="italics"/>Equilibrium<emph.end type="italics"/> between the | |
| <lb/>water and the Solid. </s><s>And, it is manife&longs;t, that putting a little more | |
| <lb/>water unto the other A F, it will increa&longs;e the Gravity and Moment, | |
| <lb/>whereupon the Pri&longs;me D G, &longs;hall be overcome, and elevated till that | |
| <lb/>the only part B F remaines &longs;ubmerged. </s><s>Which is that that was to | |
| <lb/>be demon&longs;trated.</s></p><p type="head"> | |
| | |
| <s>COROLLARY I.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>By what hath been demon&longs;trated, it is manife&longs;t, that Solids le&longs;s grave<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1417"></arrow.to.target> | |
| <lb/>in &longs;pecie <emph type="italics"/>than the water, &longs;ubmerge only &longs;o far, that as much water in | |
| <lb/>Ma&longs;s, as is the part of the Solid &longs;ubmerged, doth weigh ab&longs;olutely as | |
| <lb/>much as the whole Solid.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1417"></margin.target><emph type="italics"/>H<emph.end type="italics"/>ow far Solids | |
| <lb/>le&longs;s grave <emph type="italics"/>in &longs;pe­ | |
| <lb/>cie<emph.end type="italics"/> than water, | |
| <lb/>do &longs;ubmerge.</s></p><p type="main"> | |
| | |
| <s>For, it being &longs;uppo&longs;ed, that the Specificall Gravity of the water, | |
| <lb/>is to the Specificall Gravity of the Pri&longs;me D G, as the Altitude | |
| <lb/>D F, is to the Altitude F B; that is, as the Solid D G is to the | |
| <lb/>Solid B G; we might ea&longs;ily demon&longs;trate, that as much water in Ma&longs;s | |
| <lb/>as is equall to the Solid B G, doth weigh ab&longs;olutely as much as the | |
| <lb/>whole Solid D G; For, by the <emph type="italics"/>Lemma<emph.end type="italics"/> foregoing, the Ab&longs;olute | |
| <lb/>Gravity of a Ma&longs;s of water, equall to the Ma&longs;s B G, hath to the Ab­ | |
| <lb/>&longs;olute Gravity of the Pri&longs;me D G, a proportion compounded of the | |
| <lb/>proportions, of the Ma&longs;s B G to the Ma&longs;s G D, and of the Specifick | |
| <lb/>Gravit 7 of the water, to the Specifick Gravity of the Pri&longs;me: But | |
| <lb/>the Gravity <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> of the water, to the Gravity <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> of the | |
| <lb/>Pri&longs;me, is &longs;uppo&longs;ed to be as the Ma&longs;s G D to the Ma&longs;s G B. There­ | |
| <lb/>fore, the Ab&longs;olute Gravity of a Ma&longs;s of water, equall to the Ma&longs;s | |
| <lb/>B G, is to the Ab&longs;olute Gravity of the Solid D G, in a proportion | |
| <lb/>compounded of the proportions, of the Ma&longs;s B G to the Ma&longs;s G D, | |
| <lb/>and of the Ma&longs;s D G to the Ma&longs;s G B; which is a proportion of | |
| <lb/>equalitie. </s><s>The Ab&longs;olute Gravity, therefore, of a Ma&longs;s of Water | |
| <lb/>equall to the part of the Ma&longs;s of the Pri&longs;me B G, is equall to the Ab­ | |
| <lb/>&longs;olute Gravity of the whole Solid D G.</s></p> | |
| | |
| | |
| <pb pagenum="416"/><p type="head"> | |
| | |
| <s>COROLLARY II. | |
| <lb/><arrow.to.target n="marg1418"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1418"></margin.target><emph type="italics"/>A<emph.end type="italics"/> Rule to equi­ | |
| <lb/>librate <emph type="italics"/>S<emph.end type="italics"/>olids in | |
| <lb/>the water.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>It followes, moreover, that a Solid le&longs;s grave than the water, being put | |
| <lb/>into a Ve&longs;&longs;ell of any imaginable greatne&longs;s, and water being circumfu&longs;ed | |
| <lb/>about it to &longs;uch a height, that as much water in Ma&longs;s, as is the part of | |
| <lb/>the Solid &longs;ubmerged, doth/> weigh ab&longs;olutely as much as the whole Solid; | |
| <lb/>it &longs;hall by that water be ju&longs;tly &longs;u&longs;tained, be the circumfu&longs;ed Water in | |
| <lb/>quantity greater or le&longs;&longs;er.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>For, if the Cylinder or Pri&longs;me M, le&longs;s grave than the water, <emph type="italics"/>v. | |
| <lb/></s><s>gra.<emph.end type="italics"/> in Sub&longs;equiteriall proportion, &longs;hall be put into the capaci­ | |
| <lb/>ous Ve&longs;&longs;ell A B C D, and the water rai&longs;ed about it, to three | |
| <lb/>quarters of its height, namely, to its Levell A D: it &longs;hall be &longs;u&longs;tained | |
| <lb/>and exactly poy&longs;ed in <emph type="italics"/>Equi­ | |
| <lb/>librium.<emph.end type="italics"/> The &longs;ame will hap­ | |
| <lb/>pen, if the Ve&longs;&longs;ell E N S F | |
| <lb/><figure id="fig267"></figure> | |
| <lb/>were very &longs;mall, &longs;o, that be­ | |
| <lb/>tween the Ve&longs;&longs;ell and the So­ | |
| <lb/>lid M, there were but a very | |
| <lb/>narrow &longs;pace, and only capable of &longs;o much water, as the hundredth | |
| <lb/>part of the Ma&longs;s M, by which it &longs;hould be likewi&longs;e rai&longs;ed and erected, | |
| <lb/>as before it had been elevated to three fourths of the height of the | |
| <lb/>Solid: which to many at the fir&longs;t &longs;ight, may &longs;eem a notable Paradox, | |
| <lb/>and beget a conceit, that the Demon&longs;tration of the&longs;e effects, were | |
| <lb/>&longs;ophi&longs;ticall and fallacious: but, for tho&longs;e who &longs;o repute it, the Ex­ | |
| <lb/>periment is a means that may fully &longs;atisfie them. </s><s>But he that &longs;hall | |
| <lb/>but comprehend of what Importance Velocity of Motion is, and how | |
| <lb/>it exactly compen&longs;ates the defect and want of Gravity, will cea&longs;e to | |
| <lb/>wonder, in con&longs;idering that at the elevation of the Solid M, the great | |
| <lb/>Ma&longs;s of water A B C D abateth very little, but the little Ma&longs;s of | |
| <lb/>water E N S F decrea&longs;eth very much, and in an in&longs;tant, as the Solid | |
| <lb/>M before did li&longs;e, howbeit for a very &longs;hort &longs;pace: Whereupon the | |
| <lb/>Moment, compounded of the &longs;mall Ab&longs;olute Gravity of the water | |
| <lb/>E N S F, and of its great Velocity in ebbing, equalizeth the Force and | |
| <lb/>and Moment, that re&longs;ults from the compo&longs;icion of the immen&longs;e Gra­ | |
| <lb/>vity of the water A B C D, with its great &longs;lowne&longs;&longs;e of ebbing; | |
| <lb/>&longs;ince that in the Elevation of the Sollid M, the aba&longs;ement of the le&longs;­</s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1419"></arrow.to.target> | |
| <lb/>&longs;er water E S, is performed ju&longs;t &longs;o much more &longs;wiftly than the great | |
| <lb/>Ma&longs;s of water A C, as this is more in Ma&longs;s than that which we thus | |
| <lb/>demon&longs;trate.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1419"></margin.target><emph type="italics"/>T<emph.end type="italics"/>he proportion | |
| <lb/>according to | |
| <lb/>which water ri­ | |
| <lb/>&longs;eth and falls in | |
| <lb/>different Ve&longs;&longs;els | |
| <lb/>at the Immer&longs;i­ | |
| <lb/>on and Elevati­ | |
| <lb/>on of <emph type="italics"/>s<emph.end type="italics"/>olids.</s></p><p type="main"> | |
| | |
| <s>In the ri&longs;ing of the Solid M, its elevation hath the &longs;ame proportion | |
| <lb/>to the circumfu&longs;ed water E N S F, that the Surface of the &longs;aid water, | |
| <lb/>hath to the Superficies or Ba&longs;e of the &longs;aid Solid M; which Ba&longs;e hath | |
| <lb/>the &longs;ame proportion to the Surface of the water A D, that the aba&longs;e­ | |
| | |
| | |
| <pb pagenum="417"/>ment or ebbing of the water A C, hath to the ri&longs;e or elevation of | |
| <lb/>the &longs;aid Solid M. Therefore, by Perturbation of proportion, in the | |
| <lb/>a&longs;cent of the &longs;aid Solid M, the aba&longs;ement of the water A B C D, to | |
| <lb/>the aba&longs;ement of the water E N S F, hath the &longs;ame proportion, that the | |
| <lb/>Surface of the water E F, hath to the Surface of the water A D; | |
| <lb/>that is, that the whole Ma&longs;s of the water E N S F, hath to the whole | |
| <lb/>Ma&longs;s A B C D, being equally high: It is manife&longs;t, therefore, that | |
| <lb/>in the expul&longs;ion and elevation of the Solid M, the water E N S F | |
| <lb/>&longs;hall exceed in Velocity of <emph type="italics"/>M<emph.end type="italics"/>otion the water A B C D, a&longs;much as it | |
| <lb/>on the other &longs;ide is exceeded by that in quantity: whereupon their | |
| <lb/>Moments in &longs;uch operations, are mutually equall.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>And, for ampler confirmation, and clearer explication of this, let us | |
| <lb/>con&longs;ider the pre&longs;ent Figure, (which if I be not deceived, may &longs;erve to | |
| <lb/>detect the errors of &longs;ome Practick Mechanitians, who upon a fal&longs;e founda­ | |
| <lb/>tion &longs;ome times attempt impo&longs;&longs;ible enterprizes,) in which, unto the large | |
| <lb/>Ve&longs;&longs;ell E I D F, the narrow Funnell or Pipe I C A B is continued, and &longs;up­ | |
| <lb/>po&longs;e water infu&longs;ed into them, unto the Levell L G H, which water &longs;hall | |
| <lb/>re&longs;t in this po&longs;ition, not without admiration in &longs;ome, who cannot conceive<emph.end type="italics"/> | |
| <lb/><figure id="fig268"></figure> | |
| <lb/><emph type="italics"/>how it can be, that the heavie charge of the great | |
| <lb/>Ma&longs;s of water G D, pre&longs;&longs;ing downwards, &longs;hould | |
| <lb/>not elevate and repul&longs;e the little quantity of the | |
| <lb/>other, contained in the Funnell or Pipe C L, by | |
| <lb/>which the de&longs;cent of it is re&longs;isted and hindered: | |
| <lb/>But &longs;uch wonder &longs;hall cea&longs;e, if we begin to &longs;uppo&longs;e | |
| <lb/>the water G D to be aba&longs;ed only to Q D, and | |
| <lb/>&longs;hall afterwards con&longs;ider, what the water C L | |
| <lb/>hath done, which to give place to the other, which | |
| <lb/>is de&longs;cended from the Levell G H, to the Levell | |
| <lb/>Q O, &longs;hall of nece&longs;&longs;ity have a&longs;cended in the &longs;ame | |
| <lb/>time, from the Levell Lunto A B. </s><s>And the | |
| <lb/>a&longs;cent L B, &longs;hall be &longs;o much greater than the de­ | |
| <lb/>&longs;cent G Q, by how much the breadth of the Ve&longs;&longs;ell | |
| <lb/>G D, is greater than that of the Funnell I C; | |
| <lb/>which, in &longs;umme, is as much as the water G D, | |
| <lb/>is more than the water L C: but in regard that the Moment of the Velocity | |
| <lb/>of the Motion, in one Moveable, compen&longs;ates that of the Gravity of ano­ | |
| <lb/>ther, what wonder is it, if the &longs;wift a&longs;cent of the le&longs;&longs;er Water C L, &longs;hall | |
| <lb/>re&longs;i&longs;t the &longs;low de&longs;cent of the greater G D<emph.end type="italics"/>?</s></p><p type="main"> | |
| | |
| <s>The &longs;ame, therefore, happens in this operation, as in the Stilliard, | |
| <lb/>in which a weight of two pounds counterpoy&longs;eth an other of 200, | |
| <lb/>asoften as that &longs;hall move in the &longs;ame time, a &longs;pace 100 times great­ | |
| <lb/>er than this: which falleth out when one Arme of the Beam is an | |
| | |
| | |
| <pb pagenum="418"/>hundred times as long as the other. </s><s>Let the erroneous opinion o | |
| <lb/><arrow.to.target n="marg1420"></arrow.to.target> | |
| <lb/>tho&longs;e therefore cea&longs;e, who hold that a Ship is better, and ea&longs;ter born | |
| <lb/>up in a great abundance of water, then in a le&longs;&longs;er quantity, (<emph type="italics"/>this was | |
| <lb/>believed by<emph.end type="italics"/> Ari&longs;totle <emph type="italics"/>in his Problems, Sect. </s><s>23, Probl.<emph.end type="italics"/> 2.) it being or | |
| <lb/>the contrary true, that its po&longs;&longs;ible, that a Ship may as well float in | |
| <lb/>ten Tun of water, as in an Ocean. | |
| <lb/><arrow.to.target n="marg1421"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1420"></margin.target>A &longs;hip flotes as | |
| <lb/>well in ten Tun | |
| <lb/>of water as in an | |
| <lb/>Ocean.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1421"></margin.target>A Solid &longs;peci­ | |
| <lb/>fiaclly graver | |
| <lb/>than the water, | |
| <lb/>cannot be born | |
| <lb/>up by any quan­ | |
| <lb/>tity of it.</s></p><p type="main"> | |
| | |
| <s>But following our matter, I &longs;ay, that by what hath been hitherto | |
| <lb/>demon&longs;trated, we may under&longs;tand how, that</s></p><p type="head"> | |
| | |
| <s>COROLLARY III.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>One of the above named Solids, when more grave<emph.end type="italics"/> in &longs;pecie <emph type="italics"/>than the water, | |
| <lb/>can never be &longs;u&longs;tained, by any whatever quantity of it.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>For having &longs;een how that the Moment wherewith &longs;uch a Solid | |
| <lb/>as grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> as the water, contra&longs;ts with the Moment of any Ma&longs;s | |
| <lb/>of water what&longs;oever, is able to retain it, even to its totall Submer&longs;ion: | |
| <lb/>without its ever a&longs;cending; it remaineth, manife&longs;t, that the water is | |
| <lb/>far le&longs;s able to rai&longs;e it up, when it exceeds the &longs;ame <emph type="italics"/>in &longs;pecie<emph.end type="italics"/>: &longs;o, | |
| <lb/>that though you infu&longs;e water till its totall Submer&longs;ion, it &longs;hall &longs;till | |
| <lb/>&longs;tay at the Bottome, and with &longs;uch Gravity, and Re&longs;i&longs;tance to Eleva­ | |
| <lb/>tion, as is the exce&longs;s of its Ab&longs;olute Gravity, above the Ab&longs;olute Gra­ | |
| <lb/>vity of a Ma&longs;s equall to it, made of water, or of a Matter <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> | |
| <lb/>equally grave with the water: and, though you &longs;hould moreover | |
| <lb/>adde never &longs;o much water above the Levell of that which equalizeth | |
| <lb/>the Altitude of the Solid, it &longs;hall not, for all that, encrea&longs;e the Pre&longs;&longs;ion | |
| <lb/>or Gravitation, of the parts circumfu&longs;ed about the &longs;aid Solid, by | |
| <lb/>which greater pre&longs;&longs;ion, it might come to be repul&longs;ed, becau&longs;e, the | |
| <lb/>Re&longs;i&longs;tance is not made, but only by tho&longs;e parts of the water, which | |
| <lb/>at the Motion of the &longs;aid Solid do al&longs;o move, and the&longs;e are tho&longs;e | |
| <lb/>only, which are comprehended by the two Superficies equidi&longs;tant to | |
| <lb/>the Horizon, and their parallels, that comprehend the Altitude of the | |
| <lb/>Solid immerged in the water.</s></p><p type="main"> | |
| | |
| <s>I conceive, I have by this time &longs;ufficiently declared and opened | |
| <lb/>the way to the contemplation of the true, intrin&longs;ecall and proper | |
| <lb/>Cau&longs;es of diver&longs;e Motions, and of the Re&longs;t of many Solid Bodies in | |
| <lb/>diver&longs;e <emph type="italics"/>Mediums,<emph.end type="italics"/> and particularly in the water, &longs;hewing how all ii | |
| <lb/>effect, depend on the mutuall exce&longs;&longs;es of the Gravity of the Movea­ | |
| <lb/>bles and of the <emph type="italics"/>Mediums<emph.end type="italics"/>: and, that which did highly import, re­ | |
| <lb/>moving the Objection, which peradventure would have begotter | |
| <lb/>much doubting, and &longs;cruple in &longs;ome, about the verity of my Con­ | |
| <lb/>clu&longs;ion, namely, how that notwith&longs;tanding, that the exce&longs;s of the | |
| <lb/>Gravity of the water, above the Gravity of the Solid, demitted into | |
| <lb/>it, be the cau&longs;e of its floating and ri&longs;ing from the Bottom to the Sur­ | |
| <lb/>face, yet a quantity of water, that weighs not ten pounds, can rai&longs;e | |
| | |
| | |
| <pb pagenum="419"/>Solid that weighs above 100 pounds: in that we have demon&longs;tra­ | |
| <lb/>ted, That it &longs;ufficeth, that &longs;uch difference be found between the | |
| <lb/>Specificall Gravities of the <emph type="italics"/>Mediums<emph.end type="italics"/> and Moveables, let the particular | |
| <lb/>and ab&longs;olute Gravities be what they will: in&longs;omuch, that a Solid, | |
| <lb/>provided that it be Specifically le&longs;s grave than the water, although | |
| <lb/>its ab&longs;olute weight were 1000 pounds, yet may it be born up and | |
| <lb/>elevated by ten pounds of water, and le&longs;s: and on the contrary, a­ | |
| <lb/>nother Solid, &longs;o that it be Specifically more grave than the water, | |
| <lb/>though in ab&longs;olute Gravity it were not above a pound, yet all the | |
| <lb/>water in the Sea, cannot rai&longs;e it from the Bottom, or float it. </s><s>This | |
| <lb/>&longs;ufficeth me, for my pre&longs;ent occa&longs;ion, to have, by the above declared | |
| <lb/>Examples, di&longs;covered and demon&longs;trated, without extending &longs;uch | |
| <lb/>matters farther, and, as I might have done, into a long Treati&longs;e: | |
| <lb/>yea, but that there was a nece&longs;&longs;ity of re&longs;olving the above propo&longs;ed | |
| <lb/>doubt, I &longs;hould have contented my &longs;elf with that only, which is | |
| <lb/>demon&longs;trated by <emph type="italics"/>Archimedes,<emph.end type="italics"/> in his fir&longs;t Book <emph type="italics"/>De In&longs;identibus hu­ | |
| <lb/>mido<emph.end type="italics"/>: where in generall termes he infers and confirms the &longs;ame </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1422"></arrow.to.target> | |
| <lb/><arrow.to.target n="marg1423"></arrow.to.target> | |
| <lb/>Conclu&longs;ions, namely, that Solids (<emph type="italics"/>a<emph.end type="italics"/>) le&longs;s grave than water, &longs;wim or | |
| <lb/><arrow.to.target n="marg1424"></arrow.to.target> | |
| <lb/>float upon it, the (<emph type="italics"/>b<emph.end type="italics"/>) more grave go to the Bottom, and the (<emph type="italics"/>c<emph.end type="italics"/>) e­ | |
| <lb/><arrow.to.target n="marg1425"></arrow.to.target> | |
| <lb/>qually grave re&longs;t indifferently in all places, yea, though they &longs;hould | |
| <lb/>be wholly under water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1422"></margin.target><emph type="italics"/>Of Natation<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1423"></margin.target>(a) <emph type="italics"/>Lib. 1. Prop.<emph.end type="italics"/> 4.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1424"></margin.target>(b) <emph type="italics"/>Id. </s><s>Lib. </s><s>1. | |
| <lb/>Prop.<emph.end type="italics"/> 3.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1425"></margin.target>(c) <emph type="italics"/>Id. </s><s>Lib. 1. | |
| <lb/>Prop.<emph.end type="italics"/> 3.</s></p><p type="main"> | |
| | |
| <s>But, becau&longs;e that this Doctrine of <emph type="italics"/>Archimedes,<emph.end type="italics"/> peru&longs;ed, tran&longs;cri­ | |
| <lb/><arrow.to.target n="marg1426"></arrow.to.target> | |
| <lb/>bed and examined by <emph type="italics"/>Signor France&longs;co Buonamico,<emph.end type="italics"/> in his <emph type="italics"/>fifth Book | |
| <lb/>of Motion, Chap.<emph.end type="italics"/> 29, and afterwards by him confuted, might by the | |
| <lb/>Authority of &longs;o renowned, and famous a Philo&longs;opher, be rendered | |
| <lb/>dubious, and &longs;u&longs;pected of fal&longs;ity; I have judged it nece&longs;&longs;ary to de­ | |
| <lb/>fend it, if I am able &longs;o to do, and to clear <emph type="italics"/>Archimedes,<emph.end type="italics"/> from tho&longs;e | |
| <lb/>cen&longs;ures, with which he appeareth to be charged. <emph type="italics"/>Buonamico<emph.end type="italics"/> re­ | |
| <lb/><arrow.to.target n="marg1427"></arrow.to.target> | |
| <lb/>jecteth the Doctrine of <emph type="italics"/>Archimedes,<emph.end type="italics"/> fir&longs;t, as not con&longs;entaneous with | |
| <lb/>the Opinion of <emph type="italics"/>Aristotle,<emph.end type="italics"/> adding, that it was a &longs;trange thing to him, | |
| <lb/><arrow.to.target n="marg1428"></arrow.to.target> | |
| <lb/>that the Water &longs;hould exceed the Earth in Gravity, &longs;eeing on the | |
| <lb/>contrary, that the Gravity of water, increa&longs;eth, by means of the parti­ | |
| <lb/><arrow.to.target n="marg1429"></arrow.to.target> | |
| <lb/>cipation of Earth. </s><s>And he &longs;ubjoyns pre&longs;ently after, that he was | |
| <lb/>not &longs;atisfied with the Rea&longs;ons of <emph type="italics"/>Archimedes,<emph.end type="italics"/> as not being able with | |
| <lb/>that Doctrine, to a&longs;&longs;ign the cau&longs;e whence it comes, that a Boat and | |
| <lb/>a Ve&longs;&longs;ell, which otherwi&longs;e, floats above the water, doth &longs;ink to the | |
| <lb/>Bottom, if once it be filled with water; that by rea&longs;on of the e­ | |
| <lb/>quality of Gravity, between the water within it, and the other water | |
| <lb/>without, it &longs;hould &longs;tay a top; but yet, neverthele&longs;s, we &longs;ee it to go to | |
| <lb/>the Bottom. | |
| <lb/><arrow.to.target n="marg1430"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1426"></margin.target>The <emph type="italics"/>Authors<emph.end type="italics"/> | |
| <lb/>defence of <emph type="italics"/>Ar­ | |
| <lb/>chimedes<emph.end type="italics"/> his Do­ | |
| <lb/>ctrine, again&longs;t | |
| <lb/>the oppo&longs;itions | |
| <lb/>of <emph type="italics"/>Buonamico.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1427"></margin.target>His fir&longs;t Objecti­ | |
| <lb/>on again&longs;t the | |
| <lb/>Doctrine of <emph type="italics"/>Ar­ | |
| <lb/>chimedes.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1428"></margin.target>His Second Ob­ | |
| <lb/>jection.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1429"></margin.target>His third Obje­ | |
| <lb/>ction.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1430"></margin.target>His &longs;ourth Ob­ | |
| <lb/>jection.</s></p><p type="main"> | |
| | |
| <s>He farther addes, that <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> had clearly confuted the Ancients, | |
| <lb/>who &longs;aid, that light Bodies moved upwards, driven by the impul&longs;e </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1431"></arrow.to.target> | |
| <lb/>of the more grave Ambient: which if it were &longs;o, it &longs;hould &longs;eem of | |
| <lb/>nece&longs;&longs;ity to follow, that all naturall Bodies are by nature heavy, | |
| | |
| | |
| <pb pagenum="420"/>and none light: For that the &longs;ame would befall the Fire and Air, | |
| <lb/>if put in the Bottom of the water. </s><s>And, howbeit, <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> grants | |
| <lb/>a Pul&longs;ion in the Elements, by which the Earth is reduced into a Sphe­ | |
| <lb/>ricall Figure, yet neverthele&longs;s, in his judgement, it is not &longs;uch that it | |
| <lb/>can remove grave Bodies from their naturall places, but rather, that | |
| <lb/>it &longs;end them toward the Centre, to which (as he &longs;omewhat ob&longs;curely | |
| <lb/>continues to &longs;ay,) the water principally moves, if it in the interim | |
| <lb/>meet not with &longs;omething that re&longs;i&longs;ts it, and, by its Gravity, thru&longs;ts | |
| <lb/>it out of its place: in which ca&longs;e, if it cannot directly, yet at lea&longs;t | |
| <lb/>as well as it can, it tends to the Centre: but it happens, that light | |
| <lb/>Bodies by &longs;uch Impul&longs;ion, do all a&longs;cend upward: but this properly | |
| <lb/>they have by nature, as al&longs;o, that other of &longs;wimming. </s><s>He concludes, | |
| <lb/><arrow.to.target n="marg1432"></arrow.to.target> | |
| <lb/>la&longs;tly, that he concurs with <emph type="italics"/>Archimedes<emph.end type="italics"/> in his Conclu&longs;ions; but not | |
| <lb/>in the Cau&longs;es, which he would referre to the facile and difficult Sepa­ | |
| <lb/>ration of the <emph type="italics"/>Medium,<emph.end type="italics"/> and to the predominance of the Elements, &longs;o | |
| <lb/>that when the Moveable &longs;uperates the power of the <emph type="italics"/>Medium<emph.end type="italics"/>; as for | |
| <lb/>example, Lead doth the Continuity of water, it &longs;hall move thorow it, | |
| <lb/>el&longs;e not.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1431"></margin.target>The <emph type="italics"/>Ancients<emph.end type="italics"/> | |
| <lb/>denved <emph type="italics"/>Ao&longs;olute<emph.end type="italics"/> | |
| <lb/>Levity.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1432"></margin.target>The cau&longs;es of | |
| <lb/>Natation & Sub­ | |
| <lb/>mer&longs;ion, accord­ | |
| <lb/>ing to the Peri­ | |
| <lb/>pateticks.</s></p><p type="main"> | |
| | |
| <s>This is all that I have been able to collect, as produced again&longs;t | |
| <lb/><emph type="italics"/>Archimedes<emph.end type="italics"/> by <emph type="italics"/>Signor Buonamico<emph.end type="italics"/>: who hath not well ob&longs;erved the | |
| <lb/>Principles and Suppo&longs;itions of <emph type="italics"/>Archimedes<emph.end type="italics"/>; which yet mu&longs;t be | |
| <lb/>fal&longs;e, if the Doctrine be fal&longs;e, which depends upon them; but is | |
| <lb/>contented to alledge therein &longs;ome Inconveniences, and &longs;ome Repug­ | |
| <lb/>nances to the Doctrine and Opinion of <emph type="italics"/>Ari&longs;totle.<emph.end type="italics"/> In an&longs;wer to which | |
| <lb/>Objections, I &longs;ay, fir&longs;t, That the being of <emph type="italics"/>Archimedes<emph.end type="italics"/> Doctrine, &longs;im­ | |
| <lb/><arrow.to.target n="marg1433"></arrow.to.target> | |
| <lb/>ply different from the Doctrine of <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> ought not to move any | |
| <lb/>to &longs;u&longs;pect it, there being no cau&longs;e, why the Authority of this &longs;hould | |
| <lb/>be preferred to the Authority of the other: but, becau&longs;e, where the | |
| <lb/>decrees of Nature are indifferently expo&longs;ed to the intellectuall eyes of | |
| <lb/>each, the Authority of the one and the other, lo&longs;eth all anthentical­ | |
| <lb/>ne&longs;s of Per&longs;wa&longs;ion, the ab&longs;olute power re&longs;iding in Rea&longs;on; therefore | |
| <lb/>I pa&longs;s to that which he alledgeth in the &longs;econd place, as an ab&longs;urd con­ | |
| <lb/><arrow.to.target n="marg1434"></arrow.to.target> | |
| <lb/>&longs;equent of the Doctrine of <emph type="italics"/>Archimedes,<emph.end type="italics"/> namely, That water &longs;hould | |
| <lb/>be more grave than Earth. </s><s>But I really find not, that ever <emph type="italics"/>Archi­ | |
| <lb/>medes<emph.end type="italics"/> &longs;aid &longs;uch a thing, or that it can be rationally deduced from his | |
| <lb/>Conclu&longs;ions: and if that were manife&longs;t unto me, I verily believe, I | |
| <lb/>&longs;hould renounce his Doctrine, as mo&longs;t erroneous. </s><s>Perhapsthis Dedu­ | |
| <lb/>ction of <emph type="italics"/>Buonamico,<emph.end type="italics"/> is founded upon that which he citeth of the Ve­ | |
| <lb/>&longs;&longs;el, which &longs;wims as long as its voyd of water, but once full it &longs;inks to | |
| <lb/>the Bottom, and under&longs;tanding it of a Ve&longs;&longs;el of Earth, he infers again&longs;t | |
| <lb/><emph type="italics"/>Archimedes<emph.end type="italics"/> thus: Thou &longs;ay&longs;t that the Solids which &longs;wim, are le&longs;s grave | |
| <lb/>than water: this Ve&longs;&longs;ell &longs;wimmeth: therefore, this Ve&longs;&longs;ell is le&longs;&longs;e grave | |
| <lb/>than water. </s><s>If this be the Illation. </s><s>I ea&longs;ily an&longs;wer, granting that this | |
| <lb/>Ve&longs;&longs;ell is le&longs;&longs;e grave than water, and denying the other con&longs;equence, | |
| | |
| | |
| <pb pagenum="421"/>namely, that Earth is le&longs;s Grave than Water. </s><s>The Ve&longs;&longs;el that &longs;wims | |
| <lb/>occupieth in the water, not only a place equall to the Ma&longs;s of the | |
| <lb/>Earth, of which it is formed; but equall to the Earth and to the Air | |
| <lb/>together, contained in its concavity. </s><s>And, if &longs;uch a Ma&longs;s compoun­ | |
| <lb/>ded of Earth and Air, &longs;hall be le&longs;s grave than &longs;uch another quantity | |
| <lb/>of water, it &longs;hall &longs;wim, and &longs;hall accord with the Doctrine of <emph type="italics"/>Archi­ | |
| <lb/>medes<emph.end type="italics"/>; but if, again, removing the Air, the Ve&longs;&longs;ell &longs;hall be filled | |
| <lb/>with water, &longs;o that the Solid put in the water, be nothing but | |
| <lb/>Earth, nor occupieth other place, than that which is only po&longs;&longs;e&longs;t by | |
| <lb/>Earth, it &longs;hall then go to the Bottom, by rea&longs;on that the Earth is | |
| <lb/>heavier than the water: and this corre&longs;ponds well with the meaning | |
| <lb/>of <emph type="italics"/>Archimedes.<emph.end type="italics"/> See the &longs;ame effect illu&longs;trated, with &longs;uch another | |
| <lb/>Experiment, In pre&longs;&longs;ing a Viall Gla&longs;s to the Bottom of the water, | |
| <lb/>when it is full of Air, it will meet with great re&longs;i&longs;tance, becau&longs;e it is | |
| <lb/>not the Gla&longs;s alone, that is pre&longs;&longs;ed under water, but together with | |
| <lb/>the Gla&longs;s a great Ma&longs;s of Air, and &longs;uch, that if you &longs;hould take as | |
| <lb/>much water, as the Ma&longs;s of the Gla&longs;s, and of the Air contained in it, | |
| <lb/>you would have a weight much greater than that of the Viall, and of | |
| <lb/>its Air: and, therefore, it will not &longs;ubmerge without great violence: | |
| <lb/>but if we demit only the Gla&longs;s into the water, which &longs;hall be when | |
| <lb/>you &longs;hall fill the Gla&longs;s with water, then &longs;hall the Gla&longs;s de&longs;cend to | |
| <lb/>the Bottom; as &longs;uperiour in Gravity to the water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1433"></margin.target>The Authors an­ | |
| <lb/>&longs;wer to the fir&longs;t | |
| <lb/>Objection.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1434"></margin.target>The Authors an­ | |
| <lb/>&longs;wer to the &longs;e­ | |
| <lb/>cond Objection.</s></p><p type="main"> | |
| | |
| <s>Returning, therefore, to our fir&longs;t purpo&longs;e; I &longs;ay, that Earth is | |
| <lb/>more grave than water, and that therefore, a Solid of Earth goeth to | |
| <lb/>the bottom of it; but one may po&longs;&longs;ibly make a compo&longs;ition of Earth | |
| <lb/>and Air, which &longs;hall be le&longs;s grave than a like Ma&longs;s of Water; and | |
| <lb/>this &longs;hall &longs;wim: and yet both this and the other experiment &longs;hall | |
| <lb/>very well accord with the Doctrine of <emph type="italics"/>Archimedes.<emph.end type="italics"/> But becau&longs;e that | |
| <lb/>in my judgment it hath nothing of difficulty in it, I will not po&longs;itive­ | |
| <lb/>ly affirme that <emph type="italics"/>Signor Buonamico,<emph.end type="italics"/> would by &longs;uch a di&longs;cour&longs;e object | |
| <lb/>unto <emph type="italics"/>Archimedes<emph.end type="italics"/> the ab&longs;urdity of inferring by his doctrine, that Earth | |
| <lb/>was le&longs;s grave than Water, though I know not how to conceive what | |
| <lb/>other accident he could have induced thence.</s></p><p type="main"> | |
| | |
| <s>Perhaps &longs;uch a Probleme (in my judgement fal&longs;e) was read by | |
| <lb/><emph type="italics"/>Signor Buonamico<emph.end type="italics"/> in &longs;ome other Author, by whom peradventure it | |
| <lb/>was attributed as a &longs;ingular propertie, of &longs;ome particular Water, and | |
| <lb/>&longs;o comes now to be u&longs;ed with a double errour in confutation of <emph type="italics"/>Ar­ | |
| <lb/>chimedes,<emph.end type="italics"/> &longs;ince he &longs;aith no &longs;uch thing, nor by him that did &longs;ay it was it | |
| <lb/>meant of the common Element of Water.</s></p><p type="main"> | |
| | |
| <s>The third difficulty in the doctrine of <emph type="italics"/>Archimedes<emph.end type="italics"/> was, that he | |
| <lb/><arrow.to.target n="marg1435"></arrow.to.target> | |
| <lb/>could not render a rea&longs;on whence it aro&longs;e, that a piece of Wood, | |
| <lb/>and a Ve&longs;&longs;ell of Wood, which otherwi&longs;e floats, goeth to the bottom, | |
| <lb/>if filled with Water. <emph type="italics"/>Signor Buonamico<emph.end type="italics"/> hath &longs;uppo&longs;ed that a Ver&longs;&longs;ell | |
| <lb/>of Wood, and of Wood that by nature &longs;wims, as before is &longs;aid, | |
| | |
| | |
| <pb pagenum="422"/>goes to the bottom, if it be filled with water; of which he in the fol­ | |
| <lb/>lowing Chapter, which is the 30 of the fifth Book copiou&longs;ly di&longs;cour&longs;­ | |
| <lb/>eth: but I (&longs;peaking alwayes without diminution of his &longs;ingular | |
| <lb/>Learning) dare in defence of <emph type="italics"/>Archimedes<emph.end type="italics"/> deny this experiment, being | |
| <lb/>certain that a piece of Wood which by its nature &longs;inks not in Water, | |
| <lb/>&longs;hall not &longs;inke though it be turned and converted into the forme of a­ | |
| <lb/>ny Ve&longs;&longs;ell what&longs;oever, and then filled with Water: and he that would | |
| <lb/>readily &longs;ee the Experiment in &longs;ome other tractable Matter, and that is | |
| <lb/>ea&longs;ily reduced into &longs;everal Figures, may take pure Wax, and ma­ | |
| <lb/>king it fir&longs;t into a Ball or other &longs;olid Figure, let him adde to it &longs;o | |
| <lb/>much Lead as &longs;hall ju&longs;t carry it to the bottome, &longs;o that being a graine | |
| <lb/>le&longs;s it could not be able to &longs;inke it, and making it afterwards into | |
| <lb/>the forme of a Di&longs;h, and filling it with Water, he &longs;hall finde that with­ | |
| <lb/>out the &longs;aid Lead it &longs;hall not &longs;inke, and that with the Lead it &longs;hall de­ | |
| <lb/>&longs;cend with much &longs;lowne&longs;s: & in &longs;hort he &longs;hall &longs;atisfie him&longs;elf, that the | |
| <lb/>Water included makes no alteration. </s><s>I &longs;ay not all this while, but that | |
| <lb/>its po&longs;&longs;ible of Wood to make Barkes, which being filled with water, | |
| <lb/>&longs;inke; but that proceeds not through its Gravity, encrea&longs;ed by the | |
| <lb/>Water, but rather from the Nailes and other Iron Workes, &longs;o that | |
| <lb/>it no longer hath a Body le&longs;s grave than Water, but one mixt of Iron | |
| <lb/>and Wood, more grave than a like Ma&longs;&longs;e of Water. </s><s>Therefore let | |
| <lb/><emph type="italics"/>Signor Buonamico<emph.end type="italics"/> de&longs;i&longs;t from de&longs;iring a rea&longs;on of an effect, that is | |
| <lb/>not in nature: yea if the &longs;inking of the Woodden Ve&longs;&longs;ell when its full | |
| <lb/>of Water, may call in que&longs;tion the Doctrine of <emph type="italics"/>Archimedes,<emph.end type="italics"/> which | |
| <lb/>he would not have you to follow, is on the contrary con&longs;onant and a­ | |
| <lb/>greeable to the Doctrine of the Peripateticks, &longs;ince it aptly a&longs;&longs;ignes a | |
| <lb/>rea&longs;on why &longs;uch a Ve&longs;&longs;ell mu&longs;t, when its full of Water, de&longs;cend to the | |
| <lb/>bottom; converting the Argument the other way, we may with | |
| <lb/>&longs;afety &longs;ay that the Doctrine of <emph type="italics"/>Archimedes<emph.end type="italics"/> is true, &longs;ince it aptly agre­ | |
| <lb/>eth with true experiments, and que&longs;tion the other, who&longs;e Deducti­ | |
| <lb/>ons are fa&longs;tened upon etroneou&longs;s Conclu&longs;ions. </s><s>As for the other point | |
| <lb/>hinted in this &longs;ame In&longs;tance, where it &longs;eemes that <emph type="italics"/>Benonamico<emph.end type="italics"/> under­ | |
| <lb/>&longs;tands the &longs;ame not only of a piece of wood, &longs;haped in the forme of a | |
| <lb/>Ve&longs;&longs;ell, but al&longs;o of ma&longs;&longs;ie Wood, which filled, <emph type="italics"/>&longs;cilicet,<emph.end type="italics"/> as I believe, he | |
| <lb/>would &longs;ay, &longs;oaked and &longs;teeped in Water, goes finally to the bottom | |
| <lb/>that happens in &longs;ome poro&longs;e Woods, which, while their Poro&longs;ity is re­ | |
| <lb/>pleni&longs;hed with Air, or other Matter le&longs;s grave than Water, are Ma&longs;­ | |
| <lb/>&longs;es &longs;pecificially le&longs;s grave than the &longs;aid Water, like as is that Viall of | |
| <lb/>Gla&longs;s while&longs;t it is full of Air: but when, &longs;uch light Matter depart­ | |
| <lb/>ing, there &longs;ucceedeth Water into the &longs;ame Poro&longs;ities and Cavities, | |
| <lb/>there re&longs;ults a compound of Water and Gla&longs;s more grave than a like | |
| <lb/>Ma&longs;s of Water: but the exce&longs;s of its Gravity con&longs;i&longs;ts in the Matter | |
| <lb/>of the Gla&longs;s, and not in the Water, which cannot be graver than it | |
| <lb/>&longs;elf: &longs;o that which remaines of the Wood, the Air of its Cavi­ | |
| | |
| | |
| <pb pagenum="423"/>ties departing, if it &longs;hall be more grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than Water, fil but its | |
| <lb/>Poro&longs;ities with Water, and you &longs;hal have a Compo&longs;t of Water and | |
| <lb/>of Wood more grave than Water, but not by vertue of the Water re­ | |
| <lb/>ceived into and imbibed by the Poro&longs;ities, but of that Matter of the | |
| <lb/>Wood which remains when the Air is departed: and being &longs;uch it | |
| <lb/>&longs;hall, according to the Doctrine of <emph type="italics"/>Archimedes,<emph.end type="italics"/> goe to the bottom, | |
| <lb/>like as before, according to the &longs;ame Doctrine it did &longs;wim.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1435"></margin.target><emph type="italics"/>T<emph.end type="italics"/>he Authors an­ | |
| <lb/>&longs;wer to the third | |
| <lb/>Objection.</s></p><p type="main"> | |
| | |
| <s>As to that finally which pre&longs;ents it &longs;elf in the fourth place, namely, | |
| <lb/><arrow.to.target n="marg1436"></arrow.to.target> | |
| <lb/>that the <emph type="italics"/>Ancients<emph.end type="italics"/> have been heretofore confuted by <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> who | |
| <lb/>denying Po&longs;itive and Ab&longs;olute Levity, and truely e&longs;teeming all Bo­ | |
| <lb/>dies to be grave, &longs;aid, that that which moved upward was driven by | |
| <lb/>the circumambient Air, and therefore that al&longs;o the Doctrine of | |
| <lb/><emph type="italics"/>Archimedes,<emph.end type="italics"/> as an adherent to &longs;uch an Opinion was con­ | |
| <lb/>victed and confuted: I an&longs;wer fir&longs;t, that <emph type="italics"/>Signor Buonamico<emph.end type="italics"/> in my | |
| <lb/>judgement hath impo&longs;ed upon <emph type="italics"/>Archimedes,<emph.end type="italics"/> and deduced from his | |
| <lb/>words more than ever he intended by them, or may from his Propo­ | |
| <lb/>&longs;itions be collected, in regard that <emph type="italics"/>Archimedes<emph.end type="italics"/> neither denies, nor ad­ | |
| <lb/>mitteth Po&longs;itive Levity, nor doth he &longs;o much as mention it: &longs;o that | |
| <lb/>much le&longs;s ought <emph type="italics"/>Buonamico<emph.end type="italics"/> to inferre, that he hath denyed that it | |
| <lb/>might be the Cau&longs;e and Principle of the A&longs;cen&longs;ion of Fire, and other | |
| <lb/>Light Bodies: having but only demon&longs;trated, that Solid Bodies | |
| <lb/><arrow.to.target n="marg1437"></arrow.to.target> | |
| <lb/>more grave than Water de&longs;cend in it, according to the exce&longs;s of their | |
| <lb/>Gravity above the Gravity of that, he demon&longs;trates likewi&longs;e, how the | |
| <lb/><arrow.to.target n="marg1438"></arrow.to.target> | |
| <lb/>le&longs;s grave a&longs;cend in the &longs;ame Water, accordng to its exce&longs;s of Gra­ | |
| <lb/>ty, above the Gravity of them. </s><s>So that the mo&longs;t that can be gather­ | |
| <lb/>ed from the Dem on&longs;tration of <emph type="italics"/>Archimedes<emph.end type="italics"/> is, that like as the exce&longs;s | |
| <lb/>of the Gravity of the Moveable above the Gravity of the Water, is | |
| <lb/>the Cau&longs;e that it de&longs;cends therein, &longs;o the exce&longs;s of the Gravity of | |
| <lb/>the water above that of the Moveable, is a &longs;ufficient Cau&longs;e why it de&longs;­ | |
| <lb/>cends not, but rather betakes it &longs;elf to &longs;wim: not enquiring whe­ | |
| <lb/>ther of moving upwards there is, or is not any other Cau&longs;e contrary | |
| <lb/>to Gravity: nor doth <emph type="italics"/>Archimedes<emph.end type="italics"/> di&longs;cour&longs;e le&longs;s properly than if one | |
| <lb/>&longs;hould &longs;ay: If the South Winde &longs;hall a&longs;&longs;ault the Barke with greater | |
| <lb/><emph type="italics"/>Impetus<emph.end type="italics"/> than is the violence with which the Streame of the River car­ | |
| <lb/>ries it towards the South, the motion of it &longs;hall be towards the North: | |
| <lb/>but if the <emph type="italics"/>Impetus<emph.end type="italics"/> of the Water &longs;hall overcome that of the Winde, its | |
| <lb/>motion &longs;hall be towards the South. </s><s>The di&longs;cour&longs;e is excellent and | |
| <lb/>would be unworthily contradicted by &longs;uch as &longs;hould oppo&longs;e it, &longs;aying: | |
| <lb/>Thou mi&longs;-alledge&longs;t as Cau&longs;e of the motion of the Bark towards the | |
| <lb/>South, the <emph type="italics"/>Impetus<emph.end type="italics"/> of the Stream of the Water above that of the | |
| <lb/>South Winde; mi&longs;-alledge&longs;t I &longs;ay, for it is the Force of the North | |
| <lb/>Winde oppo&longs;ite to the South, that is able to drive the Bark towards | |
| <lb/>the South. </s><s>Such an Objection would be &longs;uperfluous, becau&longs;e he which | |
| <lb/>alledgeth for Cau&longs;e of the Motion the &longs;tream of the Water, denies not | |
| | |
| | |
| <pb pagenum="424"/>but that the Winde oppo&longs;ite to the South may do the &longs;ame, but only | |
| <lb/>affirmeth that the force of the Water prevailing over the South | |
| <lb/>Wind, the Bark &longs;hall move towards the South: and &longs;aith no more | |
| <lb/>than is true. </s><s>And ju&longs;t thus when <emph type="italics"/>Archimedes<emph.end type="italics"/> &longs;aith, that the Gravity | |
| <lb/>of the Water prevailing over that by which the moveable de&longs;cends to | |
| <lb/>the Bottom, &longs;uch moveable &longs;hall be rai&longs;ed from the Bottom to the Sur­ | |
| <lb/>face alledgeth a very true Cau&longs;e of &longs;uch an Accident, nor doth he af­ | |
| <lb/>firm or deny that there is, or is not, a vertue contrary to Gravity, called | |
| <lb/>by &longs;ome Levity, that hath al&longs;o a power of moving &longs;ome Matters up | |
| <lb/>wards. </s><s>Let therefore the Weapons of <emph type="italics"/>Signor Buonamico<emph.end type="italics"/> be directed a­ | |
| <lb/><arrow.to.target n="marg1439"></arrow.to.target> | |
| <lb/>gain&longs;t <emph type="italics"/>Plato,<emph.end type="italics"/> and other <emph type="italics"/>Ancients,<emph.end type="italics"/> who totally denying <emph type="italics"/>Levity,<emph.end type="italics"/> and taking | |
| <lb/>all Bodies to be grave, &longs;ay that the Motion upwards is made, not | |
| <lb/>from an intrin&longs;ecal Principle of the Moveable, but only by the Im­ | |
| <lb/>pul&longs;e of the <emph type="italics"/>Medium<emph.end type="italics"/>; and let <emph type="italics"/>Archimedes<emph.end type="italics"/> and his Doctrine e&longs;cape | |
| <lb/>him, &longs;ince he hath given him no Cau&longs;e of quarelling with him | |
| <lb/>But if this Apologie, produced in defence of <emph type="italics"/>Archimedes,<emph.end type="italics"/> &longs;hould &longs;een | |
| <lb/>to &longs;ome in&longs;ufficient to free him from the Objections and Arguments | |
| <lb/>produced by <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> again&longs;t <emph type="italics"/>Plato,<emph.end type="italics"/> and the other <emph type="italics"/>Ancients,<emph.end type="italics"/> as if they | |
| <lb/>did al&longs;o fight again&longs;t <emph type="italics"/>Archimedes,<emph.end type="italics"/> alledging the Impul&longs;e of the Water | |
| <lb/><arrow.to.target n="marg1440"></arrow.to.target> | |
| <lb/>as the Cau&longs;e of the &longs;wimming of &longs;ome Bodies le&longs;s grave than it, I would | |
| <lb/>not que&longs;tion, but that I &longs;hould be able to maintaine the Doctrine of | |
| <lb/><emph type="italics"/>Plato<emph.end type="italics"/> and tho&longs;e others to be mo&longs;t true, who ab&longs;olutely deny Levity, | |
| <lb/>and affirm no other Intrin&longs;ecal Principle of Motion to be in Elemen­ | |
| <lb/>tary Bodies &longs;ave only that towards the Centre of the Earth, nor no | |
| <lb/><arrow.to.target n="marg1441"></arrow.to.target> | |
| <lb/>other Cau&longs;e of moving upwards, &longs;peaking of that which hath the re­ | |
| <lb/>&longs;emblance of natural Motion, but only the repul&longs;e of the <emph type="italics"/>Medium,<emph.end type="italics"/> &longs;luid, | |
| <lb/>and exceeding the Gravity of the Moveable: and as to the Rea&longs;ons | |
| <lb/>of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> on the contrary, I believe that I could be able fully to | |
| <lb/><arrow.to.target n="marg1442"></arrow.to.target> | |
| <lb/>an&longs;wer them, and I would a&longs;&longs;ay to do it, if it were ab&longs;olutely nece&longs;&longs;a­ | |
| <lb/>ry to the pre&longs;ent Matter, or were it not too long a Digre&longs;&longs;ion for this | |
| <lb/>&longs;hort Treati&longs;e. </s><s>I will only &longs;ay, that if there were in &longs;ome of our Elle­ | |
| <lb/>mentary Bodies an Intrin&longs;ecall Principle and Naturall Inclination | |
| <lb/>to &longs;hun the Centre of the Earth, and to move towards the Concave | |
| <lb/>of the Moon, &longs;uch Bodies, without doubt, would more &longs;wiftly a&longs;cend | |
| <lb/>through tho&longs;e <emph type="italics"/>Mediums<emph.end type="italics"/> that lea&longs;t oppo&longs;e the Velocity of the Moveable, | |
| <lb/>and the&longs;e are the more tenuous and &longs;ubtle; as is, for example, the | |
| <lb/>Air in compari&longs;on of the Water, we daily proving that we can with | |
| <lb/><arrow.to.target n="marg1443"></arrow.to.target> | |
| <lb/>farre more expeditious Velocity move a Hand or a Board to and a­ | |
| <lb/>gain in one than in the other: neverthele&longs;s, we never could finde any | |
| <lb/>Body, that did not a&longs;cend much more &longs;wiftly in the water than in the | |
| <lb/><arrow.to.target n="marg1444"></arrow.to.target> | |
| <lb/>Air. </s><s>Yea of Bodies which we &longs;ee continually to a&longs;cend in the Water, | |
| <lb/>there is none that having arrived to the confines of the Air, do not whol­ | |
| <lb/>ly lo&longs;e their Motion; even the Air it &longs;elf, which ri&longs;ing with great Ce­ | |
| <lb/>lerity through the Water, being once come to its Region it lo&longs;eth all</s></p> | |
| | |
| | |
| <pb pagenum="425"/><p type="margin"> | |
| | |
| <s><margin.target id="marg1436"></margin.target>The Authors | |
| <lb/>an&longs;wer to the | |
| <lb/>fourth Object­ | |
| <lb/>ion.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1437"></margin.target>Of Natation, | |
| <lb/>Lib. 1. Prop. </s><s>7.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1438"></margin.target>Of Natation, | |
| <lb/>Lib. </s><s>1. Prop. </s><s>4.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1439"></margin.target><emph type="italics"/>Plato<emph.end type="italics"/> denyeth | |
| <lb/>Po&longs;itive Levi­ | |
| <lb/>ty.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1440"></margin.target>The Authors | |
| <lb/>defence of the | |
| <lb/>doctrine of <emph type="italics"/>Plato<emph.end type="italics"/> | |
| <lb/>and the <emph type="italics"/>Ancients,<emph.end type="italics"/> | |
| <lb/>who ab&longs;olutely | |
| <lb/>deny Levity:</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1441"></margin.target>According to | |
| <lb/><emph type="italics"/>Plato<emph.end type="italics"/> there is no | |
| <lb/>Principle of the | |
| <lb/>Motion of de­ | |
| <lb/>&longs;cent in Naturall | |
| <lb/>Bodies, &longs;ave that | |
| <lb/>to the Centre.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1442"></margin.target>No cau&longs;e of | |
| <lb/>the motion of | |
| <lb/><emph type="italics"/>A<emph.end type="italics"/> cent, &longs;ave the | |
| <lb/>Impul&longs;e of the | |
| <lb/><emph type="italics"/>Medium,<emph.end type="italics"/> exceed­ | |
| <lb/>ing the Move­ | |
| <lb/>able in Gravi­ | |
| <lb/>tie.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1443"></margin.target>Bodies a&longs;cend | |
| <lb/>much &longs;wifter in | |
| <lb/>the Water, than | |
| <lb/>in the Air.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1444"></margin.target>All Bodies a&longs;­ | |
| <lb/>cending through | |
| <lb/>Water, lo&longs;e | |
| <lb/>their Motion, | |
| <lb/>comming to the | |
| <lb/>confines of the | |
| <lb/>Air.</s></p><p type="main"> | |
| | |
| <s>And, howbeit, Experience &longs;hewes, that the Bodies, &longs;ucce&longs;&longs;ively | |
| <lb/><arrow.to.target n="marg1445"></arrow.to.target> | |
| <lb/>le&longs;s grave, do mo&longs;t expeditiou&longs;ly a&longs;cend in water, it cannot be doubt­ | |
| <lb/>ed, but that the Ignean Exhalations do a&longs;cend more &longs;wiftly | |
| <lb/><arrow.to.target n="marg1446"></arrow.to.target> | |
| <lb/>through the water, than doth the Air: which Air is &longs;een by Experi­ | |
| <lb/>ence to a&longs;cend more &longs;wiftly through the Water, than the Fiery Exha­ | |
| <lb/>lations through the Air: Therefore, we mu&longs;t of nece&longs;&longs;ity conclude, | |
| <lb/>that the &longs;aid Exhalations do much more expeditiou&longs;ly a&longs;cend through | |
| <lb/>the Water, than through the Air; and that, con&longs;equently, they are | |
| <lb/>moved by the Impul&longs;e of the Ambient <emph type="italics"/>Medium,<emph.end type="italics"/> and not by an intrin­ | |
| <lb/>&longs;ick Principle that is in them, of avoiding the Centre of the Earth; | |
| <lb/>to which other grave Bodies tend.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1445"></margin.target>The lighter | |
| <lb/>Bodies al&longs;end | |
| <lb/>more &longs;wiftly | |
| <lb/>through Water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1446"></margin.target>Fiery Exhalati­ | |
| <lb/>ons ascend tho­ | |
| <lb/>row the Water | |
| <lb/>more &longs;wiftly | |
| <lb/>than doth the | |
| <lb/>Air; & the Air | |
| <lb/>a&longs;cends more | |
| <lb/>&longs;wiftly thorow | |
| <lb/>the Water, than | |
| <lb/><emph type="italics"/>F<emph.end type="italics"/>ire thorow the | |
| <lb/>Air.</s></p><p type="main"> | |
| | |
| <s>To that which for a finall conclu&longs;ion, <emph type="italics"/>Signor Buonamico<emph.end type="italics"/> produceth | |
| <lb/><arrow.to.target n="marg1447"></arrow.to.target> | |
| <lb/>of going about to reduce the de&longs;cending or not de&longs;cending, to the | |
| <lb/>ea&longs;ie and unea&longs;ie Divi&longs;ion of the <emph type="italics"/>Medium,<emph.end type="italics"/> and to the predominancy | |
| <lb/>of the Elements: I an&longs;wer, as to the fir&longs;t part, that that cannot in any | |
| <lb/>manner be admitted as a Cau&longs;e, being that in none of the Fluid | |
| <lb/><emph type="italics"/>Mediums,<emph.end type="italics"/> as the Air, the Water, and other Liquids, there is any | |
| <lb/><arrow.to.target n="marg1448"></arrow.to.target> | |
| <lb/>Re&longs;i&longs;tance again&longs;t Divi&longs;ion, but all by every the lea&longs;t Force, are di­ | |
| <lb/>vided and penetrated, as I will anon demon&longs;trate: &longs;o, that of &longs;uch | |
| <lb/>Re&longs;i&longs;tance of Divi&longs;ion there can be no Act, &longs;ince it &longs;elf is not in be­ | |
| <lb/>ing. </s><s>As to the other part, I &longs;ay, that the predominancy of the Ele­ | |
| <lb/><arrow.to.target n="marg1449"></arrow.to.target> | |
| <lb/>ments in Moveables, is to be con&longs;idered, as far as to the exce&longs;&longs;e or | |
| <lb/>defect of Gravity, in relation to the <emph type="italics"/>Medium<emph.end type="italics"/>: for in that Action, | |
| <lb/>the Elements operate not, but only, &longs;o far as they are grave or light: | |
| <lb/>therefore, to &longs;ay that the Wood of the Firre &longs;inks not, becau&longs;e Air | |
| <lb/>predominateth in it, is no more than to &longs;ay, becau&longs;e it is le&longs;s grave | |
| <lb/>than the Water. </s><s>Yea, even the immediate Cau&longs;e, is its being le&longs;s | |
| <lb/>grave than the Water: and it being under the predominancy of the | |
| <lb/><arrow.to.target n="marg1450"></arrow.to.target> | |
| <lb/>Air, is the Cau&longs;e of its le&longs;s Gravity: Therefore, he that alledgeth the | |
| <lb/>predominancy of the Element for a Cau&longs;e, brings the Cau&longs;e of the | |
| <lb/>Cau&longs;e, and not the neere&longs;t and immediate Cau&longs;e. </s><s>Now, who knows | |
| <lb/>not that the true Cau&longs;e is the immediate, and not the mediate? | |
| <lb/><arrow.to.target n="marg1451"></arrow.to.target> | |
| <lb/>Moreover, he that alledgeth Gravity, brings a Cau&longs;e mo&longs;t per&longs;picuous | |
| <lb/>to Sence: The cau&longs;e we may very ea&longs;ily a&longs;&longs;ertain our &longs;elves; | |
| <lb/>whether Ebony, for example, and Firre, be more or le&longs;s grave than | |
| <lb/>water: but whether Earth or Air predominates in them, who &longs;hall | |
| <lb/><arrow.to.target n="marg1452"></arrow.to.target> | |
| <lb/>make that manife&longs;t? </s><s>Certainly, no Experiment can better do it | |
| <lb/>than to ob&longs;erve whether they &longs;wim or &longs;ink. </s><s>So, that he who knows, | |
| <lb/>not whether &longs;uch a Solid &longs;wims, unle&longs;s when he knows that Air pre­ | |
| <lb/>dominates in it, knows not whether it &longs;wim, unle&longs;s he &longs;ees it &longs;wim, | |
| <lb/>for then he knows that it &longs;wims, when he knows that it is Air that | |
| <lb/>predominates, but knows not that Air hath the predominance, unle&longs;s | |
| <lb/>he &longs;ees it &longs;wim: therefore, he knows not if it &longs;wims, till &longs;uch time | |
| <lb/>as he hath &longs;een it &longs;wim.</s></p> | |
| | |
| | |
| <pb pagenum="426"/><p type="margin"> | |
| | |
| <s><margin.target id="marg1447"></margin.target><emph type="italics"/>T<emph.end type="italics"/>he Authors | |
| <lb/>confutation of | |
| <lb/>the Peripateticks | |
| <lb/>Cau&longs;es of Nata­ | |
| <lb/>tion & Submer&longs;i­ | |
| <lb/>on.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1448"></margin.target>Water & other | |
| <lb/>fluids void of | |
| <lb/>Re&longs;i&longs;tance a­ | |
| <lb/>gain&longs;t Divi&longs;ion.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1449"></margin.target><emph type="italics"/>T<emph.end type="italics"/>he predomi­ | |
| <lb/>nancy of Ele­ | |
| <lb/>ments in Move­ | |
| <lb/>ables to be con­ | |
| <lb/>&longs;idered only in | |
| <lb/>relation to their | |
| <lb/>excefs or defect | |
| <lb/>of Gravity in | |
| <lb/>reference to the | |
| <lb/><emph type="italics"/>Medium.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1450"></margin.target><emph type="italics"/>T<emph.end type="italics"/>he immedi­ | |
| <lb/>ate Cau&longs;e of Na­ | |
| <lb/>tation is that the | |
| <lb/>Moveable is le&longs;s | |
| <lb/>grave than the | |
| <lb/>Water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1451"></margin.target><emph type="italics"/>T<emph.end type="italics"/>he <emph type="italics"/>P<emph.end type="italics"/>eripate­ | |
| <lb/>ticks alledge for | |
| <lb/>the rea&longs;on of | |
| <lb/>Natation the | |
| <lb/>Cau&longs;e of the | |
| <lb/>Cau&longs;e.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1452"></margin.target>Gravity a | |
| <lb/>Cau&longs;e mo&longs;t per­ | |
| <lb/>&longs;picuous to | |
| <lb/>&longs;ence:</s></p><p type="main"> | |
| | |
| <s>Let us not then de&longs;pi&longs;e tho&longs;e Hints, though very dark, which | |
| <lb/>Rea&longs;on, after &longs;ome contemplation, offereth to our Intelligence, and | |
| <lb/>lets be content to be taught by <emph type="italics"/>Archimedes,<emph.end type="italics"/> that then any Body &longs;hall | |
| <lb/><arrow.to.target n="marg1453"></arrow.to.target> | |
| <lb/>&longs;ubmerge in water, when it &longs;hall be &longs;pecifically more grave than it | |
| <lb/>and that if it &longs;hall be le&longs;s grave, it &longs;hall of nece&longs;&longs;ity &longs;wim, and | |
| <lb/><arrow.to.target n="marg1454"></arrow.to.target> | |
| <lb/>that it will re&longs;t indifferently in any place under water, if its Gravity | |
| <lb/>be perfectly like to that of the water. | |
| <lb/><arrow.to.target n="marg1455"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1453"></margin.target>Lib 1. of Na­ | |
| <lb/>tation Prop. </s><s>7.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1454"></margin.target>Id. </s><s>Lib. 1. | |
| <lb/>Prop. </s><s>4.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1455"></margin.target>Id. </s><s>Lib. </s><s>1: | |
| <lb/>Prop. </s><s>3.</s></p><p type="main"> | |
| | |
| <s>The&longs;e things explained and proved, I come to con&longs;ider that which | |
| <lb/>offers it &longs;elf, touching what the Diver&longs;ity of figure given unto the | |
| <lb/>&longs;aid Moveable hath to do with the&longs;e Motions and Re&longs;ts; and pro­ | |
| <lb/>ceed to affirme, that,</s></p><p type="head"> | |
| | |
| <s>THEOREME V.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>The diver&longs;ity of Figures given to this or that Solid<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1456"></arrow.to.target> | |
| <lb/><emph type="italics"/>cannot any way be a Cau&longs;e of its ab&longs;olute Sinking or | |
| <lb/>Swimming.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1456"></margin.target>Diver&longs;ity of | |
| <lb/>Figure no Cau&longs;e | |
| <lb/>of its ab&longs;olute | |
| <lb/>Natation or Sub­ | |
| <lb/>mer&longs;ion.</s></p><p type="main"> | |
| | |
| <s>So that if a Solid being formed, for example, into a Spherical | |
| <lb/>Figure, doth &longs;ink or &longs;wim in the water, I &longs;ay, that being formed | |
| <lb/>into any other Figure, the &longs;ame figure in the &longs;ame water, &longs;hall | |
| <lb/>&longs;ink or &longs;wim: nor can &longs;uch its Motion by the Expan&longs;ion or by o­ | |
| <lb/>ther mutation of Figure, be impeded or taken away. | |
| <lb/><arrow.to.target n="marg1457"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1457"></margin.target>The Expan&longs;i­ | |
| <lb/>on of <emph type="italics"/>F<emph.end type="italics"/>igure, re­ | |
| <lb/>tards the Veloci­ | |
| <lb/>ty of the a&longs;cent | |
| <lb/>or de&longs;cent of the | |
| <lb/>Moveable in the | |
| <lb/>water; but doth | |
| <lb/>not deprive it of | |
| <lb/>all Motion.</s></p><p type="main"> | |
| | |
| <s>The Expan&longs;ion of the Figure may indeed retard its Velocity, a&longs; | |
| <lb/>well of a&longs;cent as de&longs;cent, and more and more according as the &longs;aid Fi­ | |
| <lb/>gure is reduced to a greater breadth and thinne&longs;s: but that it may bere | |
| <lb/>duced to &longs;uch a form as that that &longs;ame matter be wholly hindred from | |
| <lb/>moving in the &longs;ame water, that I hold to be impo&longs;&longs;ible. </s><s>In this I have | |
| <lb/>met with great contradictors, who producing &longs;ome Experiments, and | |
| <lb/>in perticular a thin Board of Ebony, and a Ball of the &longs;ame Wood | |
| <lb/>and &longs;hewing how the Ball in Water de&longs;cended to the bottom, and | |
| <lb/>the Board being put lightly upon the Water &longs;ubmerged not, but re&longs;t­ | |
| <lb/>ed; have held, and with the Authority of <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> confirmed them | |
| <lb/>&longs;elves in their Opinions, that the Cau&longs;e of that Re&longs;t was the breadth | |
| <lb/>of the Figure, u able by its &longs;mall weight to pierce and penetrate the | |
| <lb/>Re&longs;i&longs;tance of the Waters Cra&longs;&longs;itude, which Re&longs;i&longs;tance is readily o­ | |
| <lb/>vercome by the other Sphericall Figure.</s></p><p type="main"> | |
| | |
| <s>This is the Principal point in the pre&longs;ent Que&longs;tion, in which I per­ | |
| <lb/>&longs;wade my &longs;elf to be on the right &longs;ide.</s></p><p type="main"> | |
| | |
| <s>Therefore, beginning to inve&longs;tigate with the examination of ex­ | |
| <lb/>qui&longs;ite Experiments that really the Figure doth not a jot alter the de&longs;­ | |
| <lb/>cent or A&longs;cent of the &longs;ame Solids, and having already demon&longs;tra­ | |
| <lb/>ted that the greater or le&longs;s Gravity of the Solid in relation to the Gra­ | |
| <lb/>vity of the <emph type="italics"/>Medium<emph.end type="italics"/> is the cau&longs;e of De&longs;cent or A&longs;cent: when ever we | |
| | |
| | |
| <pb pagenum="427"/>would make proof of that, which about this Effect the diver&longs;ity of Fi­ | |
| <lb/>gure worketh, its nece&longs;&longs;ary to make the Experiment with Matter | |
| <lb/>wherein variety of Gravities hath no place. </s><s>For making u&longs;e of Mat­ | |
| <lb/>ters which may be different in their Specifical Gravities, and meeting | |
| <lb/>with varieties of effects of A&longs;cending and De&longs;cending, we &longs;hall al­ | |
| <lb/>wayes be left un&longs;atisfied whether that diver&longs;ity derive it &longs;elf really | |
| <lb/>from the &longs;ole Figure, or el&longs;e from the divers Gravity al&longs;o. </s><s>We may | |
| <lb/>remedy this by takeing one only Matter, that is tractable and ea&longs;ily | |
| <lb/>reduceable into every &longs;ort of Figure. </s><s>Moreover, it wil be an excellent | |
| <lb/>expedient to take a kinde of Matter, exactly alike in Gravity unto the | |
| <lb/>Water: for that Matter, as far as pertaines to the Gravity, is in­ | |
| <lb/>different either to A&longs;cend or De&longs;cend; &longs;o that we may pre&longs;ently ob­ | |
| <lb/>&longs;erve any the lea&longs;t difference that derives it &longs;elf from the diver&longs;ity of | |
| <lb/>Figure.</s></p><p type="main"> | |
| | |
| <s>Now to do this, Wax is mo&longs;t apt, which, be&longs;ides its incapacity of </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1458"></arrow.to.target> | |
| <lb/>receiveing any &longs;en&longs;ible alteration from its imbibing of Water, is duct­ | |
| <lb/>ile or pliant, and the &longs;ame piece is ea&longs;ily reduceable into all Figures: | |
| <lb/>and being <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> a very incon&longs;iderable matter inferiour in Gravity | |
| <lb/>to the Water, by mixing therewith a little of the fileings of Lead it is | |
| <lb/>reduced to a Gravity exactly equall to that of the Water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1458"></margin.target>An Experi­ | |
| <lb/>ment in Wax, | |
| <lb/>that proveth Fi­ | |
| <lb/>gute to have no | |
| <lb/>Operation in | |
| <lb/>Natation & Sub­ | |
| <lb/>mer&longs;ion.</s></p><p type="main"> | |
| | |
| <s>This Matter prepared, and, for example, a Ball being made there­ | |
| <lb/>of as bigge as an Orange or biger, and that made &longs;o grave as to | |
| <lb/>&longs;ink to the bottom, but &longs;o lightly, that takeing thence one only Grain | |
| <lb/>of Lead, it returnes to the top, and being added, it &longs;ubmergeth to | |
| <lb/>the bottom, let the &longs;ame Wax afterwards be made into a very broad | |
| <lb/>and thin Flake or Cake; and then, returning to make the &longs;ame Ex­ | |
| <lb/>periment, you &longs;hall &longs;ee that it being put to the bottom, it &longs;hall, with the | |
| <lb/>Grain of Lead re&longs;t below, and that Grain deducted, it &longs;hall a&longs;cend to | |
| <lb/>the very Surface, and added again it &longs;hall dive to the bottom. </s><s>And | |
| <lb/>this &longs;ame effect &longs;hall happen alwaies in all &longs;ort of Figures, as wel re­ | |
| <lb/>gular as irregular: nor &longs;hall you ever finde any that will &longs;wim with­ | |
| <lb/>out the removall of the Grain of Lead, or &longs;inke to the bottom unle&longs;s | |
| <lb/>it be added: and, in &longs;hort, about the going or not going to the Bot­ | |
| <lb/>tom, you &longs;hall di&longs;cover no diver&longs;ity, although, indeed, you &longs;hall about | |
| <lb/>the quick and &longs;low de&longs;cent: for the more expatiated and di&longs;tended | |
| <lb/>Figures move more &longs;lowly a&longs;wel in the diveing to the bottom as in | |
| <lb/>the ri&longs;ing to the top; and the other more contracted and compact Fi­ | |
| <lb/>gures, more &longs;peedily. </s><s>Now I know not what may be expected from | |
| <lb/>the diver&longs;ity of Figures, if the mo&longs;t contrary to one another operate | |
| <lb/>not &longs;o much as doth a very &longs;mall Grain of Lead, added or removed.</s></p><p type="main"> | |
| | |
| <s>Me thinkes I hear &longs;ome of the Adver&longs;aries to rai&longs;e a doubt upon | |
| <lb/><arrow.to.target n="marg1459"></arrow.to.target> | |
| <lb/>my produced Experiment. </s><s>And fir&longs;t, that they offer to my con&longs;idera­ | |
| <lb/>tion, that the Figure, as a Figure &longs;imply, and disjunct from the Matter | |
| <lb/>workes not any effect, but requires to be conjoyned with the Matter­ | |
| | |
| | |
| <pb pagenum="428"/>and, furthermore, not with every Matter, but with tho&longs;e only, | |
| <lb/>wherewith it may be able ro execute the de&longs;ired operation. </s><s>Like | |
| <lb/>as we &longs;ee it verified by Experience, that the Acute and &longs;harp Angle is | |
| <lb/>more apt to cut, than the Obtu&longs;e; yet alwaies provided, that both | |
| <lb/>the one and the other, be joyned with a Matter apt to cut, as for | |
| <lb/>example, with Steel. </s><s>Therefore, a Knife with a fine and &longs;harp | |
| <lb/>edge, cuts Bread or Wood with much ea&longs;e, which it will not do, if | |
| <lb/>the edge be blunt and thick: but he that will in&longs;tead of Steel, take | |
| <lb/>Wax, and mould it into a Knife, undoubtedly &longs;hall never know the | |
| <lb/>effects of &longs;harp and blunt edges: becau&longs;e neither of them will cut, | |
| <lb/>the Wax being unable by rea&longs;on of its flexibility, to overcome the | |
| <lb/>hardne&longs;s of the Wood and Bread. </s><s>And, therefore, applying the | |
| <lb/>like di&longs;cour&longs;e to our purpo&longs;e, they &longs;ay, that the difference of Figure | |
| <lb/>will &longs;hew different effects, touching Natation and Submer&longs;ion, but | |
| <lb/>not conjoyned with any kind of Matter, but only with tho&longs;e Matters | |
| <lb/>which, by their Gravity, are apt to re&longs;i&longs;t the Velocity of the water, | |
| <lb/>whence he that would elect for the Matter, Cork or other light wood | |
| <lb/>unable, through its Levity, to &longs;uperate the Cra&longs;&longs;itude of the water, | |
| <lb/>and of that Matter &longs;hould forme Solids of divers Figures, woulld in | |
| <lb/>vain &longs;eek to find out what operation Figure hath in Natation or Sub­ | |
| <lb/>mer&longs;ion; becau&longs;e all would &longs;wim, and that not through any property | |
| <lb/>of this or that Figure, but through the debility of the Matter, want­ | |
| <lb/>ing &longs;o much Gravity, as is requi&longs;ite to &longs;uperate and overcome the | |
| <lb/>Den&longs;ity and Cra&longs;&longs;itude of the water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1459"></margin.target>An objection a­ | |
| <lb/>gain&longs;t the Expe­ | |
| <lb/>riment in Wax.</s></p><p type="main"> | |
| | |
| <s>Its needfull, therefore, if wee would &longs;ee the effect wrought by the | |
| <lb/>Diver&longs;ity of Figure, fir&longs;t to make choice of a Matter of its nature | |
| <lb/>apt to penetrate the Cra&longs;&longs;itude of the water. </s><s>And, for this effect, | |
| <lb/><arrow.to.target n="marg1460"></arrow.to.target> | |
| <lb/>they have made choice of &longs;uch a Matter, as fit, that being readily re­ | |
| <lb/>duced into Sphericall Figure, goes to the Bottom; and it is Ebony | |
| <lb/>of which they afterwards making a &longs;mall Board or Splinter, as thin as | |
| <lb/>a Lath, have illu&longs;trated how that this, put upon the Surface of the | |
| <lb/>water, re&longs;ts there without de&longs;cending to the Bottom: and making, on | |
| <lb/>the other&longs;ide, of the &longs;ame wood a Ball, no le&longs;s than a hazell Nut, | |
| <lb/>they &longs;hew, that this &longs;wims not, but de&longs;cendes. </s><s>From which Experi­ | |
| <lb/>ment, they think they may frankly conclude, that the Breadth ofthe | |
| <lb/>Figure in the flat Lath or Board, is the cau&longs;e of its not de&longs;cendingto | |
| <lb/>the Bottom, fora&longs;much as a Ball of the &longs;ame Matter, not different | |
| <lb/>from the Board in any thing but in Figure, &longs;ubmergeth in the &longs;ame | |
| <lb/>water to the Bottom. </s><s>The di&longs;cour&longs;e and the Experiment hath really | |
| <lb/>&longs;o much of probability and likely hood of truth in it, that it would be | |
| <lb/>no wonder, if many per&longs;waded by a certain cur&longs;ory ob&longs;ervation, | |
| <lb/>&longs;hould yield credit to it; neverthele&longs;s, I think I am able to di&longs;cover, | |
| <lb/>how that it is not free from falacy.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1460"></margin.target>An Experi­ | |
| <lb/>ment in Ebany, | |
| <lb/>brought to di&longs;­ | |
| <lb/>prove the Expe­ | |
| <lb/>timent in Wax.</s></p><p type="main"> | |
| | |
| <s>Beginning, therefore, to examine one by one, all the particulars that | |
| | |
| | |
| <pb pagenum="429"/>have been produced, I &longs;ay, that Figures, as &longs;imple Figures, not only | |
| <lb/><arrow.to.target n="marg1461"></arrow.to.target> | |
| <lb/>operate not in naturall things, but neither are they ever &longs;eperated | |
| <lb/>from the Corporeall &longs;ub&longs;tance: nor have I ever alledged them &longs;tript | |
| <lb/>of &longs;en&longs;ible Matter, like as al&longs;o I freely admit, that in our endeavour­ | |
| <lb/>ing to examine the Diver&longs;ity of Accidents, dependant upon the va­ | |
| <lb/>riety of Figures, it is nece&longs;&longs;ary to apply them to Matters, which ob­ | |
| <lb/>&longs;truct not the various operations of tho&longs;e various Figures: and I ad­ | |
| <lb/>mit and grant, that I &longs;hould do very ill, if I would experiment the in­ | |
| <lb/>fluence of Acutene&longs;&longs;e of edge with a Knife of Wax, applying it to cut | |
| <lb/>an Oak, becau&longs;e there is no Acutene&longs;s in Wax able to cut that | |
| <lb/>very hard wood. </s><s>But yet &longs;uch an Experiment of this Knife, would | |
| <lb/>not be be&longs;ides the purpo&longs;e, to cut curded Milk, or other very yielding | |
| <lb/>Matter: yea, in &longs;uch like Matters, the Wax is more commodious | |
| <lb/>than Steel; for finding the diver&longs;ity depending upon Angles, more or | |
| <lb/>le&longs;s Acute, for that Milk is indifferently cut with a Rai&longs;or, and with | |
| <lb/>a Knife, that hath a blunt edge. </s><s>It needs, therefore, that regard be | |
| <lb/>had, not only to the hardne&longs;s, &longs;olidity or Gravity of Bodies, which | |
| <lb/>under divers figures, are to divide and penetrate &longs;ome Matters, but it | |
| <lb/>forceth al&longs;o, that regard be had, on the other &longs;ide, to the Re&longs;i&longs;tance | |
| <lb/>of the Matters, to be divided and penetrated. </s><s>But &longs;ince I have in | |
| <lb/>making the Experiment concerning our Conte&longs;t, cho&longs;en a Matter | |
| <lb/>which penetrates the Re&longs;i&longs;tance of the water; and in all figures de&longs;­ | |
| <lb/>cendes to the Bottome, the Adver&longs;aries can charge me with no defect; | |
| <lb/>yea, I have propounded &longs;o much a more excellent Method than they, | |
| <lb/>in as much as I have removed all other Cau&longs;es, of de&longs;cending or | |
| <lb/>not de&longs;cending to the Bottom, and retained the only &longs;ole and pure | |
| <lb/>variety of Figures, demon&longs;trating that the &longs;ame Figures all de&longs;cende | |
| <lb/>with the only alteration of a Grain in weight: which Grain being | |
| <lb/>removed, they return to float and &longs;wim; it is not true, therefore, | |
| <lb/>(re&longs;uming the Example by them introduced) that I have gon about | |
| <lb/>to experiment the efficacy of Acutene&longs;s, in cutting with Matters un­ | |
| <lb/>able to cut, but with Matters proportioned to our occa&longs;ion; &longs;ince | |
| <lb/>they are &longs;ubjected to no other variety, then that alone which depends | |
| <lb/>on the Figure more or le&longs;s a cute. | |
| <lb/><arrow.to.target n="marg1462"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1461"></margin.target>Figure is un­ | |
| <lb/>&longs;eperable from | |
| <lb/>Corporeall Sub­ | |
| <lb/>&longs;tance.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1462"></margin.target>The an&longs;wer to | |
| <lb/>the Objection a­ | |
| <lb/>gain&longs;t the Expe­ | |
| <lb/>riment of the | |
| <lb/>Wax.</s></p><p type="main"> | |
| | |
| <s>But let us proceed a little farther, and ob&longs;erve, how that indeed | |
| <lb/>the Con&longs;ideration, which, they &longs;ay, ought to be had about the Election | |
| <lb/>of the Matter, to the end, that it may be proportionate for the ma­ | |
| <lb/>king of our experiment, is needle&longs;ly introduced, declaring by the ex­ | |
| <lb/>ample of Cutting, that like as Acutene&longs;s is in&longs;ufficient to cut, unle&longs;s | |
| <lb/>when it is in a Matter hard and apt to &longs;uperate the Re&longs;i&longs;tance of the | |
| <lb/>wood or other Matter, which we intend to cut; &longs;o the aptitude of | |
| <lb/>de&longs;cending or notde&longs;cending in water, ought and can only be known | |
| <lb/>in tho&longs;e Matters, that are able to overcome the Renitence, and &longs;upe­ | |
| <lb/>rate the Cra&longs;&longs;itude of the water. </s><s>Unto which, I &longs;ay, that to make | |
| <lb/>di&longs;tinction and election, more of this than of that Matter, on which to | |
| | |
| | |
| <pb pagenum="430"/>impre&longs;s the Figures for cutting or penetrating this or that Body, | |
| <lb/>as the &longs;olidity or obduratene&longs;s of the &longs;aid Bodies &longs;hall be greater | |
| <lb/>or le&longs;s, is very nece&longs;&longs;ary: but withall I &longs;ubjoyn, that &longs;uch di&longs;tinct­ | |
| <lb/>ion, election and caution would be &longs;uperfluous and unprofitable, if | |
| <lb/>the Body to be cut or penetrated, &longs;hould have no Re&longs;i&longs;tance, or | |
| <lb/>&longs;hould not at all with&longs;tand the Cutting or Penitration: and if the | |
| <lb/>Knife were to be u&longs;ed in cutting a Mi&longs;t or Smoak, one of Paper | |
| <lb/>would be equally &longs;erviceable with one of <emph type="italics"/>Dama&longs;cus<emph.end type="italics"/> Steel: and &longs;o | |
| <lb/>by rea&longs;on the water hath not any Re&longs;i&longs;tance again&longs;t the Penitration | |
| <lb/>of any Solid Body, all choice of Matter is &longs;uperfluous and needle&longs;s, | |
| <lb/>and the Election which I &longs;aid above to have been well made of a | |
| <lb/>Matter reciprocall in Gravity to water, was not becau&longs;e it was ne­ | |
| <lb/>ce&longs;&longs;ary, for the overcoming of the cra&longs;&longs;iitude of the water, but its | |
| <lb/>Gravity, with which only it re&longs;i&longs;ts the &longs;inking of Solid Bodies: and | |
| <lb/>for what concerneth the Re&longs;i&longs;tance of the cra&longs;&longs;itude, if we narrowly | |
| <lb/>con&longs;ider it, we &longs;hall find that all Solid Bodies, as well tho&longs;e that | |
| <lb/>&longs;ink, as tho&longs;e that &longs;wim, are indifferently accomodated and apt to | |
| <lb/>bring us to the knowledge of the truth in que&longs;tion. </s><s>Nor will I | |
| <lb/>be frighted out of the belief of the&longs;e Conclu&longs;ions, by the Experi­ | |
| <lb/>ments which may be produced again&longs;t me, of many &longs;everall Woods, | |
| <lb/>Corks, Galls, and, moreover, of &longs;ubtle &longs;lates and plates of all &longs;orts | |
| <lb/>of Stone and Mettall, apt by means of their Naturall Gravity, to | |
| <lb/>move towards the Centre of the Earth, the which, neverthele&longs;s, be­ | |
| <lb/>ing impotent, either through the Figure (as the Adver&longs;aries thinke) | |
| <lb/>or through Levity, to break and penetrate the Continuity of the | |
| <lb/>parts of the water, and to di&longs;tract its union, do continue to &longs;wimm | |
| <lb/>without &longs;ubmerging in the lea&longs;t: nor on the other &longs;ide, &longs;hall the | |
| <lb/>Authority of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> move me, who in more than one place, a&longs;&longs;ir­ | |
| <lb/>meth the contrary to this, which Experience &longs;hews me.</s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1463"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1463"></margin.target>No Solid of | |
| <lb/>&longs;uch Levity, nor | |
| <lb/>of &longs;uch Figure, | |
| <lb/>but that it doth | |
| <lb/>penetrate the | |
| <lb/>Cra&longs;&longs;itude of | |
| <lb/>the Water.</s></p><p type="main"> | |
| | |
| <s>I return, therefore, to a&longs;&longs;ert, that there is not any Solid of &longs;uch | |
| <lb/>Levity, nor of &longs;uch Figure, that being put upon the water, doth not | |
| <lb/>divide and penetrate its Cra&longs;&longs;itude: yea if any with a more per­ | |
| <lb/>&longs;picatious eye, &longs;hall return to ob&longs;erve more exactly the thin Boards | |
| <lb/>of Wood, he &longs;hall &longs;ee them to be with part of their thickne&longs;s under </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1464"></arrow.to.target> | |
| <lb/>water, and not only with their inferiour Superficies, to ki&longs;&longs;e the | |
| <lb/>Superiour of the water, as they of nece&longs;&longs;ity mu&longs;t have believed, who | |
| <lb/>have &longs;aid, that &longs;uch Boards &longs;ubmerge not, as not being able to di­ | |
| <lb/>vide the Tenacity of the parts of the water: and, moreover, he | |
| <lb/>&longs;hall &longs;ee, that &longs;ubtle &longs;hivers of Ebony, Stone or Metall, when they | |
| <lb/>float, have not only broak the Continuity of the water, but are with | |
| <lb/>all their thickne&longs;s, under the Surface of it; and more and more, | |
| <lb/>according as the Matters are more grave: &longs;o that a thin Plate of | |
| <lb/>Lead, &longs;hall be lower than the Surface of the circumfu&longs;ed water, by | |
| <lb/>at lea&longs;t twelve times the thickne&longs;s of the Plate, and Gold &longs;hall dive | |
| | |
| | |
| <pb pagenum="431"/>below the Levell of the water, almo&longs;t twenty times the thickne&longs;s | |
| <lb/>of the Plate, as I &longs;hall anon declare.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1464"></margin.target>Bodies of all | |
| <lb/>Figures, laid up­ | |
| <lb/>on the water, do | |
| <lb/>penetrate its | |
| <lb/>Cra&longs;&longs;itude, and | |
| <lb/>in what propor­ | |
| <lb/>tion.</s></p><p type="main"> | |
| | |
| <s>But let us proceed to evince, that the water yields and &longs;ufters it | |
| <lb/>&longs;elf to be penetrated by every the lighte&longs;t Body; and therewithall | |
| <lb/>demon&longs;trate, how, even by Matters that &longs;ubmerge not, we may | |
| <lb/>come to know that Figure operates nothing about the going or | |
| <lb/>not going to the Bottom, &longs;eeing that the water &longs;uffers it &longs;elf to be | |
| <lb/>penetrated equally by every Figure.</s></p><p type="main"> | |
| | |
| <s>Make a Cone, or a Piramis of Cypre&longs;s, of Firre, or of other | |
| <lb/><arrow.to.target n="marg1465"></arrow.to.target> | |
| <lb/>Wood of like Gravity, or of pure Wax, and let its height be &longs;ome­ | |
| <lb/>what great, namely a handfull, or more, and put it into the water | |
| <lb/>with the Ba&longs;e downwards: fir&longs;t, you &longs;hall &longs;ee that it will penetrate | |
| <lb/>the water, nor &longs;hall it be at all impeded by the largene&longs;s of the Ba&longs;e, | |
| <lb/>nor yet &longs;hall it &longs;ink all under water, but the part towards the point | |
| <lb/>&longs;hall lye above it: by which &longs;hall be manife&longs;t, fir&longs;t, that that Solid | |
| <lb/>forbeares not to &longs;ink out of an inabillity to divide the Continuity | |
| <lb/>of the water, having already divided it with its broad part, that in | |
| <lb/>the opinion of the Adver&longs;aries is the le&longs;s apt to make the divi&longs;ion. | |
| <lb/></s><s>The Piramid being thus fixed, note what part of it &longs;hall be &longs;ub­ | |
| <lb/>merged, and revert it afterwards with the point downwards, and | |
| <lb/>you &longs;hall &longs;ee that it &longs;hall not dive into the water more than before, | |
| <lb/>but if you ob&longs;erve how far it &longs;hall &longs;ink, every per&longs;on expert in | |
| <lb/>Geometry, may mea&longs;ure, that tho&longs;e parts that remain out of the | |
| <lb/>water, both in the one and in the other Experiment are equall to | |
| <lb/>an hair: whence he may manife&longs;tly conclude, that the acute Figure | |
| <lb/>which &longs;eemed mo&longs;t apt to part and penetrate the water, doth not | |
| <lb/>part or penetrate it more than the large and &longs;pacious.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1465"></margin.target>The Experi­ | |
| <lb/>ment of a Cone, | |
| <lb/>demitted with | |
| <lb/>its Ba&longs;e, and af­ | |
| <lb/>ter with its | |
| <lb/>Point down­ | |
| <lb/>wards.</s></p><p type="main"> | |
| | |
| <s>And he that would have a more ea&longs;ie Experiment, let him take | |
| <lb/>two Cylinders of the &longs;ame Matter, one long and &longs;mall, and the o­ | |
| <lb/>ther &longs;hert, but very broad, and let him put them in the water, not | |
| <lb/>di&longs;tended, but erect and endways: he &longs;hall &longs;ee, if he diligently | |
| <lb/>mea&longs;ure the parts of the one and of the other, that in each of them | |
| <lb/>the part &longs;ubmerged, retains exactly the &longs;ame proportion to that | |
| <lb/>out of the water, and that no greater part is &longs;ubmerged of that | |
| <lb/>long and &longs;mall one, than of the other more &longs;pacious and broad: | |
| <lb/>howbeit, this re&longs;ts upon a very large, and that upon a very little | |
| <lb/>Superficies of water: therefore the diver&longs;ity of Figure, occa&longs;ioneth | |
| <lb/>neither facility, nor difficulty, in parting and penetrating the Con­ | |
| <lb/>tinuity of the water; and, con&longs;equently, cannot be the Cau&longs;e of the | |
| <lb/>Natation or Submer&longs;ion. </s><s>He may likewi&longs;e di&longs;cover the non­ | |
| <lb/>operating of variety of Figures, in ari&longs;ing from the Bottom of the | |
| <lb/>water, towards the Surface, by taking Wax, and tempering it with | |
| <lb/>a competent quantity of the filings of Lead, &longs;o that it may become | |
| <lb/>a con&longs;iderable matter graver than the water: then let him make | |
| | |
| | |
| <pb pagenum="432"/>it into a Ball, and thru&longs;t it unto the Bottom of the water; and | |
| <lb/>fa&longs;ten to it as much Cork, or other light matter, as ju&longs;t &longs;erveth to | |
| <lb/>rai&longs;e it, and draw it towards the Surface: for afterwards changing | |
| <lb/>the &longs;ame Wax into a thin Cake, or into any other Figure, that | |
| <lb/>&longs;ame Cork &longs;hall rai&longs;e it in the &longs;ame manner to a hair.</s></p><p type="main"> | |
| | |
| <s>This &longs;ilenceth not my Antagoni&longs;ts, but they &longs;ay, that all the | |
| <lb/>di&longs;cour&longs;e hitherto made by me little importeth to them, and that it | |
| <lb/>&longs;erves their turn, that they have demon&longs;trated in one only parti­ | |
| <lb/>cular, and in what matter, and under what Figure plea&longs;eth them, | |
| <lb/>namely, in a Board and in a Ball of Ebony, that this put in the | |
| <lb/>water, de&longs;cends to the Bottom, and that &longs;tays atop to &longs;wim: | |
| <lb/>and the Matter being the &longs;ame, and the two Bodies differing in no­ | |
| <lb/>thing but in Figure, they affirm, that they have with all per&longs;picuity | |
| <lb/>demon&longs;trated and &longs;en&longs;ibly manife&longs;ted what they undertook; and | |
| <lb/>la&longs;tly, that they have obtained their intent. </s><s>Neverthele&longs;s, I believe, | |
| <lb/>and thinke, I can demon&longs;trate, that that &longs;ame Experiment proveth | |
| <lb/>nothing again&longs;t my Conclu&longs;ion.</s></p><p type="main"> | |
| | |
| <s>And fir&longs;t, it is fal&longs;e, that the Ball de&longs;cends, and the Board not: | |
| <lb/><arrow.to.target n="marg1466"></arrow.to.target> | |
| <lb/>for the Board &longs;hall al&longs;o de&longs;cend, if you do to both the Figures, as | |
| <lb/>the words of our Que&longs;tion requireth; that is, if you put them both | |
| <lb/>into the water. | |
| <lb/><arrow.to.target n="marg1467"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1466"></margin.target>In Experi­ | |
| <lb/>ments of Nata­ | |
| <lb/>tion, the Solid | |
| <lb/>is to be put into, | |
| <lb/>not upon the | |
| <lb/>water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1467"></margin.target>The Que&longs;tion | |
| <lb/>of Natation &longs;ta­ | |
| <lb/>ted.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>The words were the&longs;e. </s><s>That the Antagoni&longs;ts having an opinion, that | |
| <lb/>the Figure would alter the Solid Bodies, in relation to the de&longs;cending | |
| <lb/>or not de&longs;cending, a&longs;cending or not a&longs;cending in the &longs;ame<emph.end type="italics"/> Medium, <emph type="italics"/>as<emph.end type="italics"/> | |
| <lb/>v. </s><s>gr. <emph type="italics"/>in the &longs;ame water, in &longs;uch &longs;ort, that, for Example, a Solid that | |
| <lb/>being of a Sphericall Figure, &longs;hall de&longs;cend to the Bottom, being reduced | |
| <lb/>into &longs;ome other Figure, &longs;hall not de&longs;cend: I holding the contrary, do | |
| <lb/>affirm, that a Corporeall Solid Body, which reduced into a Sphericall Fi­ | |
| <lb/>gure, or any other, &longs;hall go to the Bottom, &longs;hall do the like under what&longs;oever | |
| <lb/>other Figure, &c.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>But to be in the water, implies to be placed in the water, and by </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1468"></arrow.to.target> | |
| <lb/><emph type="italics"/>Ari&longs;totles<emph.end type="italics"/> own Definition of place, to be placed, importeth to be in­ | |
| <lb/>vironed by the Superficies of the Ambient Body, therefore, then | |
| <lb/>&longs;hall the two Figures be in the water, when the Superficies of the | |
| <lb/>water, &longs;hall imbrace and inviron them: but when the Adver&longs;aries | |
| <lb/>&longs;hew the Board of Ebony not de&longs;cending to the Bottom, they put it | |
| <lb/>not into the water, but upon the water, where being by a certain im­ | |
| <lb/>pediment (as by and by we will &longs;hew) retained, it is invironed, part | |
| <lb/>by water, and part by air, which thing is contrary to our agreement, | |
| <lb/>that was, that the Bodies &longs;hould be in the water, and not part in | |
| <lb/>water, and part in air.</s></p> | |
| | |
| | |
| <pb pagenum="433"/><p type="margin"> | |
| | |
| <s><margin.target id="marg1468"></margin.target>Place defined | |
| <lb/>according to | |
| <lb/><emph type="italics"/>Ari&longs;totle.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>The which is again made manifest, by the que&longs;tions being put as well | |
| <lb/>about the things which go to the Bottom, as tho&longs;e which ari&longs;e from the | |
| <lb/>Bottom to &longs;wimme, and who &longs;ees not that things placed in the Bottom, | |
| <lb/>mu&longs;t have water about them.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>It is now to be noted, that the Board of Ebany and the Ball, put | |
| <lb/><arrow.to.target n="marg1469"></arrow.to.target> | |
| <lb/><emph type="italics"/>into<emph.end type="italics"/> the water, both &longs;ink, but the Ball more &longs;wiftly, and the Board | |
| <lb/>more &longs;lowly; and &longs;lower and &longs;lower, according as it &longs;hall be more | |
| <lb/>broad and thin, and of this Tardity the breadth of the Figure is the | |
| <lb/>true Cau&longs;e: But the&longs;e broad Boards that &longs;lowly de&longs;cend, are the | |
| <lb/>&longs;ame, that being put lightly upon the water, do &longs;wimm: Therefore, | |
| <lb/>if that were true which the Adver&longs;aries affirm, the &longs;ame numerical | |
| <lb/>Figure, would in the &longs;ame numericall water, cau&longs;e one while Re&longs;t, and | |
| <lb/>another while Tardity of Motion, which is impo&longs;&longs;ible: for every per­ | |
| <lb/><arrow.to.target n="marg1470"></arrow.to.target> | |
| <lb/>ticular Figure which de&longs;cends to the Bottom, hath of nece&longs;&longs;ity its own | |
| <lb/>determinate Tardity and &longs;lowne&longs;s, proper and naturall unto it, accor­ | |
| <lb/>ding to which it moveth, &longs;o that every other Tardity, greater or le&longs;&longs;er | |
| <lb/>is improper to its nature: if, therefore, a Board, as &longs;uppo&longs;e of a foot | |
| <lb/>&longs;quare, de&longs;cendeth naturally with &longs;ix degrees of Tardity, it is impo&longs;&longs;i­ | |
| <lb/>ble, that it &longs;hould de&longs;cend with ten or twenty, unle&longs;s &longs;ome new impe­ | |
| <lb/>diment do arre&longs;t it. </s><s>Much le&longs;s can it, by rea&longs;on of the &longs;ame Figure | |
| <lb/>re&longs;t, and wholly cea&longs;e to move; but it is nece&longs;&longs;ary, that when ever it | |
| <lb/>re&longs;teth, there do &longs;ome greater impediment intervene than the breadth | |
| <lb/>of the Figure. </s><s>Therefore, it mu&longs;t be &longs;omewhat el&longs;e, and not the Fi­ | |
| <lb/>gure, that &longs;tayeth the Board of Ebany above water, of which Eigure | |
| <lb/>the only Effect is the retardment of the Motion, according to which | |
| <lb/>it de&longs;cendeth more &longs;lowly than the Ball. </s><s>Let it be confe&longs;&longs;ed, there­ | |
| <lb/>fore, rationally di&longs;cour&longs;ing, that the true and &longs;ole Cau&longs;e of the Ebanys | |
| <lb/>going to the Bottom, is the exce&longs;s of its Gravity above the Gravity of | |
| <lb/>the water: and the Cau&longs;e of the greater or le&longs;s Tardity, the breadth | |
| <lb/>of this Figure, or the contractedne&longs;s of that: but of its Re&longs;t, it can | |
| <lb/>by no means be allowed, that the quallity of the Figure, is the Cau&longs;e | |
| <lb/>thereof: a&longs;well, becau&longs;e, making the Tardity greater, according as | |
| <lb/>the Figure more dilateth, there cannot be &longs;o immen&longs;e a Dilatation, to | |
| <lb/>which there may not be found a corre&longs;pondent immence Tardity. | |
| <lb/></s><s>without redu&longs;ing it to Nullity of Motion; as, becau&longs;e the Figures | |
| <lb/>produced by the Antagoni&longs;ts for effecters of Re&longs;t, are the &longs;elf &longs;ame | |
| <lb/>that do al&longs;o go to the Bottom. | |
| <lb/><arrow.to.target n="marg1471"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1469"></margin.target>The con&longs;utati­ | |
| <lb/>on of the Expe­ | |
| <lb/>riment in the | |
| <lb/>Ebany.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1470"></margin.target>Every perticular | |
| <lb/>Figure hath its | |
| <lb/>own peculiat | |
| <lb/>Tardity.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1471"></margin.target>* The Figure & | |
| <lb/>Re&longs;i&longs;tance of | |
| <lb/>the Medium a­ | |
| <lb/>gain&longs;t Divi&longs;ion, | |
| <lb/>have nothing to | |
| <lb/>do with the Ef­ | |
| <lb/>fect of Natation | |
| <lb/>or Submer&longs;ion, | |
| <lb/>by an Experi­ | |
| <lb/>ment in Wall­ | |
| <lb/>nut tree,</s></p><p type="main"> | |
| | |
| <s>I will not omit another rea&longs;on, founded al&longs;o upon Experience, and | |
| <lb/>if I deceive not my &longs;elf, manife&longs;tly concluding, how that the Intro­ | |
| <lb/>ducton of the breadth or amplitude of Figure, and the Re&longs;i&longs;tance of | |
| <lb/>the water again&longs;t penetration, have nothing to do in the Effect of de­ | |
| <lb/>&longs;cending, or a&longs;cending, or re&longs;ting in the water. ^{*}Take a piece of wood | |
| <lb/>or other Matter, of which a Ball a&longs;cends from the Bottom of the water | |
| | |
| | |
| <pb pagenum="434"/>to the Surface, more &longs;lowly than a Ball of Ebony of the &longs;ame bigne&longs;&longs;e, | |
| <lb/>&longs;o that it is manife&longs;t, that the Ball of Ebony more readily divideth the | |
| <lb/>water in de&longs;cending, than the other in a&longs;cending; as for Example, let | |
| <lb/>the Wood be Walnut-tree. </s><s>Then take a Board of Walnut-tree, like | |
| <lb/>and equall to that of Ebony of the Antagoni&longs;ts, which &longs;wims; and if | |
| <lb/>it be true, that this floats above water, by rea&longs;on of the Figure, unable | |
| <lb/>through its breadth, to pierce the Cra&longs;&longs;itude of the &longs;ame, the other of | |
| <lb/>Wallnut-tree, without all que&longs;tion, being thru&longs;t unto the Bottom, will | |
| <lb/>&longs;tay there, as le&longs;s apt, through the &longs;ame impediment of Figure, to di­ | |
| <lb/>vide the &longs;aid Re&longs;i&longs;tance of the water. </s><s>But if we &longs;hall find, and by | |
| <lb/>experience &longs;ee, that not only the thin Board, but every other Figure | |
| <lb/>of the &longs;ame Wallnut-tree will return to float, as undoubtedly we &longs;hall, | |
| <lb/>then I mu&longs;t de&longs;ier my oppo&longs;ers to forbear to attribute the floating of | |
| <lb/>the Ebony, unto the Figure of the Board, in regard that the Re&longs;i&longs;tance | |
| <lb/>of the water is the &longs;ame, as well to the a&longs;cent, as to the de&longs;cent, and the | |
| <lb/>force of the Wallnut-trees a&longs;cen&longs;ion, is le&longs;&longs;e than the Ebonys force in | |
| <lb/>going to the Bottom.</s></p><p type="main"> | |
| | |
| | |
| <s>Nay, I will &longs;ay more, that if we &longs;hall con&longs;ider Gold in compari&longs;on | |
| <lb/><arrow.to.target n="marg1472"></arrow.to.target> | |
| <lb/>of water, we &longs;hall find, that it exceeds it in Gravity almo&longs;t twenty times, | |
| <lb/>&longs;o that the Force and Impetus, wherewith a Ball of Gold goes to the | |
| <lb/>Bottom, is very great. </s><s>On the contrary, there want not matters, as | |
| <lb/>Virgins Wax, and &longs;ome Woods, which are not above a fiftieth part le&longs;s | |
| <lb/>grave than water, whereupon their A&longs;cen&longs;ion therein is very &longs;low, and | |
| <lb/>a thou&longs;and times weaker than the <emph type="italics"/>Impetus<emph.end type="italics"/> of the Golds de&longs;cent: yet | |
| <lb/>notwith&longs;tanding, a plate of Gold &longs;wims without de&longs;cending to the | |
| <lb/>Bottom, and, on the contrary, we cannot make a Cake of Wax, or thin | |
| <lb/>Board of Wood, which put in the Bottom of the Water, &longs;hall re&longs;t there | |
| <lb/>without a&longs;cending. </s><s>Now if the Figure can ob&longs;truct the Penetration, | |
| <lb/>and impede the de&longs;cent of Gold, that hath &longs;o great an <emph type="italics"/>Impetus,<emph.end type="italics"/> how | |
| <lb/>can it choo&longs;e but &longs;uffice to re&longs;i&longs;t the &longs;ame Penetration of the other mat­ | |
| <lb/>ter in a&longs;cending, when as it hath &longs;carce a thou&longs;andth part of the <emph type="italics"/>Impetus<emph.end type="italics"/> | |
| <lb/>that the Gold hath in de&longs;cending? </s><s>Its therefore, nece&longs;&longs;ary, that that | |
| <lb/>which &longs;u&longs;pends the thin Plate of Gold, or Board of Ebony, upon the | |
| <lb/>water, be &longs;ome thing that is wanting to the other Cakes and Boards of | |
| <lb/>Matters le&longs;s grave than the water; &longs;ince that being put to the Bottom, | |
| <lb/>and left at liberty, they ri&longs;e up to the Surface, without any ob&longs;truction: | |
| <lb/>But they want not for flatne&longs;s and breadth of Figure: Therefore, the | |
| <lb/>&longs;paciou&longs;ne&longs;&longs;e of the Figure, is not that which makes the Gold and Ebony | |
| <lb/>to &longs;wim.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1472"></margin.target>An Experi­ | |
| <lb/>ment in Gold, to | |
| <lb/>prove the non­ | |
| <lb/>operating of Fi­ | |
| <lb/>gure in Natation | |
| <lb/>and Submer&longs;ion.</s></p><p type="main"> | |
| | |
| <s>And, becau&longs;e, that the exce&longs;s of their Gravity above the Gravity of | |
| <lb/>the water, is que&longs;tionle&longs;s the Cau&longs;e of the &longs;inking of the flat piece of | |
| <lb/>Ebony, and the thin Plate of Gold, when they go to the Bottom, there­ | |
| <lb/>fore, of nece&longs;&longs;ity, when they float, the Cau&longs;e of their &longs;taying above | |
| <lb/>water, proceeds from Levity, which in that ca&longs;e, by &longs;ome Accident, | |
| | |
| | |
| <pb pagenum="435"/>peradventure not hitherto ob&longs;erved, cometh to meet with the &longs;aid | |
| <lb/>Board, rendering it no longer as it was before, whil&longs;t it did fink more | |
| <lb/>ponderous than the water, but le&longs;s.</s></p><p type="main"> | |
| | |
| <s>Now, let us return to take the thin Plate of Gold, or of Silver, or the | |
| <lb/>thin Board of Ebony, and let us lay it lightly upon the water, &longs;o that it | |
| <lb/>&longs;tay there without &longs;inking, and diligently ob&longs;erve its effect. </s><s>And | |
| <lb/>fir&longs;t, &longs;ee how fal&longs;e the a&longs;&longs;ertion of <emph type="italics"/>Aristotle,<emph.end type="italics"/> and our oponents is, to wit, | |
| <lb/>that it &longs;tayeth above water, through its unability to pierce and pene­ | |
| <lb/>trate the Re&longs;i&longs;tance of the waters Cra&longs;&longs;itude: for it will manife&longs;tly | |
| <lb/>appear, not only that the &longs;aid Plates have penetrated the water, but | |
| <lb/>al&longs;o that they are a con&longs;iderable matter lower than the Surface of the | |
| <lb/>&longs;ame, the which continueth eminent, and maketh as it were a Rampert | |
| <lb/>on all &longs;ides, round about the &longs;aid Plates, the profundity of which they | |
| <lb/>&longs;tay &longs;wimming: and, according as the &longs;aid Plates &longs;hall be more grave | |
| <lb/>than the water, two, four, ten or twenty times, it is nece&longs;&longs;ary, that | |
| <lb/>their Superficies do &longs;tay below the univer&longs;all Surface of the water, &longs;o | |
| <lb/>much more, than the thickne&longs;s of tho&longs;e Plates, as we &longs;hal more di&longs;tinctly | |
| <lb/>&longs;hew anon. </s><s>In the mean &longs;pace, for the more ea&longs;ie under&longs;tanding of what | |
| <lb/>I &longs;ay, ob&longs;erve with me a little the pre&longs;ent | |
| <lb/><figure id="fig269"></figure> | |
| <lb/>Scheme: in which let us &longs;uppo&longs;e the Surface | |
| <lb/>of the water to be di&longs;tended, according to the | |
| <lb/>Lines F L D B, upon which if one &longs;hall put a | |
| <lb/>board of matter &longs;pecifically more grave than | |
| <lb/>water, but &longs;o lightly that it &longs;ubmetge not, it | |
| <lb/>&longs;hall not re&longs;t any thing above, but &longs;hall enter with its whole thickne&longs;s | |
| <lb/>into the water: and, moreover, &longs;hall &longs;ink al&longs;o, as we &longs;ee by the Board | |
| <lb/>A I, O I, who&longs;e breadth is wholly &longs;unk into the water, the little Ram­ | |
| <lb/>perts of water L A and D O incompa&longs;&longs;ing it, who&longs;e Superficies is no­ | |
| <lb/>tably higher than the Superficies of the Board. </s><s>See now whether it be | |
| <lb/>true, that the &longs;aid Board goes not to the Bottom, as being of Figure | |
| <lb/>unapt to penetrate the Cra&longs;&longs;itude of the water.</s></p><p type="main"> | |
| | |
| <s>But, if it hath already penetrated, and overcome the Continuity of | |
| <lb/><arrow.to.target n="marg1473"></arrow.to.target> | |
| <lb/>the water, & is of its own nature more grave than the &longs;aid water, why | |
| <lb/>doth it not proceed in its &longs;inking, but &longs;top and &longs;u&longs;pend its &longs;elf within | |
| <lb/>that little dimple or cavitie, which with its pondero&longs;ity it hath made in | |
| <lb/>the water? </s><s>I an&longs;wer; becau&longs;e that in &longs;ubmerging it &longs;elf, &longs;o far as till its | |
| <lb/>Superficies come to the Levell with that of the water, it lo&longs;eth a part | |
| <lb/>of its Gravity, and lo&longs;eth the re&longs;t of it as it &longs;ubmergeth & de&longs;cends be­ | |
| <lb/>neath the Surface of the water, which maketh Ramperts and Banks | |
| <lb/>round about it, and it &longs;u&longs;taines this lo&longs;s by means of its drawing after it, | |
| <lb/>and carrying along with it, the Air that is above it, and by Contact ad­ | |
| <lb/>herent to it, which Air &longs;ucceeds to fill the Cavity that is invironed by | |
| <lb/>the Ramperts of water: &longs;o that that which in this ca&longs;e de&longs;cends and is | |
| <lb/>placed in the water, is not only the Board of Ebony or Plate of Iron, | |
| | |
| | |
| <pb pagenum="436"/>but a compo&longs;ition of Ebony and Air, from which re&longs;ulteth a Solid | |
| <lb/>no longer &longs;uperiour in Gravity to the water, as was the &longs;imple Ebony, | |
| <lb/>or the &longs;imple Gold. </s><s>And, if we exactly con&longs;ider, what, and how | |
| <lb/>great the Solid is, that in this Experiment enters into the water, and | |
| <lb/>contra&longs;ts with the Gravity of the &longs;ame, it will be found to be all that | |
| <lb/>which we find to be beneath the Surface of the water, the which is | |
| <lb/>an aggregate and Compound of a Board of Ebony, and of almo&longs;t | |
| <lb/>the like quantity of Air, or a Ma&longs;s compounded of a Plate of Lead, | |
| <lb/>and ten or twelve times as much Air. </s><s>But, Genrlemen, you that | |
| <lb/>are my Antagoni&longs;ts in our Que&longs;tion, we require the Identity of | |
| <lb/>Matter, and the alteration only of the Figure; therefore, you mu&longs;t | |
| <lb/>remove that Air, which being conjoyned with the Board, makes it | |
| <lb/>become another Body le&longs;s grave than the Water, and put only the | |
| <lb/>Ebony into the Water, and you &longs;hall certainly &longs;ee the Board de&longs;cend | |
| <lb/>to the Bottom; and, if that do not happen, you have got the day. | |
| <lb/><arrow.to.target n="marg1474"></arrow.to.target> | |
| <lb/>And to &longs;eperate the Air from the Ebony, there needs no more but | |
| <lb/>only to bath the Superficies of the &longs;aid Board with the &longs;ame Water: | |
| <lb/>for the Water being thus interpo&longs;ed between the Board and the Air, | |
| <lb/>the other circumfu&longs;ed Water &longs;hall run together without any impedi­ | |
| <lb/>ment, and &longs;hall receive into it the &longs;ole and bare Ebony, as it was to do.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1473"></margin.target>Why &longs;olids | |
| <lb/>having penitra­ | |
| <lb/>ted the Water, | |
| <lb/>do not proceed | |
| <lb/>to a totail Sub­ | |
| <lb/>mer&longs;ion.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1474"></margin.target>How to &longs;epe­ | |
| <lb/>rate the Air from | |
| <lb/>Solids in demit­ | |
| <lb/>ting them into | |
| <lb/>the water.</s></p><p type="main"> | |
| | |
| <s>But, me thinks I hear &longs;ome of the Adver&longs;aries cunningly oppo&longs;ing | |
| <lb/>this, and telling me, that they will not yield, by any means, that | |
| <lb/>their Board be wetted, becau&longs;e the weight added thereto by the | |
| <lb/>Water, by making it heavier than it was before, draws it to the | |
| <lb/>Bottom, and that the addition of new weight is contrary to our a­ | |
| <lb/>greement, which was, that the Matter be the &longs;ame.</s></p><p type="main"> | |
| | |
| <s>To this, I an&longs;wer, fir&longs;t; that treating of the operation of Figure | |
| <lb/>in Bodies put into the Water, none can &longs;uppo&longs;e them to be put into | |
| <lb/>the Water without being wet; nor do I de&longs;ire more to be done to | |
| <lb/>the Board, then I will give you leave to do to the Ball. </s><s>Moreover, | |
| <lb/>it is untrue, that the Board &longs;inks by vertue of the new Weight added | |
| <lb/>to it by the Water, in the &longs;ingle and &longs;light bathing of it: for I will | |
| <lb/>put ten or twenty drops of Water upon the &longs;ame Board, whil&longs;t it is | |
| <lb/>&longs;u&longs;tained upon the water, which drops, becau&longs;e not conjoyned with | |
| <lb/>the other Water circumfu&longs;ed, &longs;hall not &longs;o encrea&longs;e the weight of it, as | |
| <lb/>to make it &longs;ink: but if the Board being taken out, and all the water | |
| <lb/>wiped off that was added thereto, I &longs;hould bath all its Superficies | |
| <lb/>with one only very &longs;mall drop, and put it again upon the water, with­ | |
| <lb/>out doubt it &longs;hall &longs;ink, the other Water running to cover it, not be­ | |
| <lb/>ing retained by the &longs;uperiour Air; which Air by the interpo&longs;ition of | |
| <lb/>the thin vail of water, that takes away its Contiguity unto the Ebony, | |
| <lb/>&longs;hall without Renitence be &longs;eperated, nor doth it in the lea&longs;t oppo&longs;e | |
| <lb/>the &longs;ucce&longs;&longs;ion of the other Water: but rather, to &longs;peak better, it | |
| <lb/>&longs;hall de&longs;cend freely; becau&longs;e it &longs;hall be all invironed and covered | |
| | |
| | |
| <pb pagenum="437"/>with water, as &longs;oon as its &longs;uperiour Superficies, before vailed with | |
| <lb/>water, doth arrive to the Levell of the univer&longs;all Surface of the &longs;aid | |
| <lb/>water. </s><s>To &longs;ay, in the next place, that water can encrea&longs;e the weight | |
| <lb/><arrow.to.target n="marg1475"></arrow.to.target> | |
| <lb/>of things that are demitted into it, is mo&longs;t fal&longs;e, for water hath no | |
| <lb/>Gravity in water, &longs;ince it de&longs;cends not: yea, if we would well con&longs;i­ | |
| <lb/>der what any immen&longs;e Ma&longs;s of water doth put upon a grave Body; | |
| <lb/><arrow.to.target n="marg1476"></arrow.to.target> | |
| <lb/>that is placed in it, we &longs;hall find experimentally, that it, on the con­ | |
| <lb/>trary, will rather in a great part demini&longs;h the weight of it, and that | |
| <lb/>we may be able to lift an huge Stone from the Bottom of the water, | |
| <lb/>which the water being removed, we are not able to &longs;tir. </s><s>Nor let | |
| <lb/>them tell me by way of reply, that although the &longs;uperpo&longs;ed water | |
| <lb/>augment not the Gravity of things that are in it, yet it increa&longs;eth the | |
| <lb/>pondero&longs;ity of tho&longs;e that &longs;wim, and are part in the water and part | |
| <lb/><arrow.to.target n="marg1477"></arrow.to.target> | |
| <lb/>in the Air, as is &longs;een, for Example, in a Bra&longs;s Ketle, which whil&longs;t it | |
| <lb/>is empty of water, and repleni&longs;hed only with Air &longs;hall &longs;wim, but | |
| <lb/>pouring of Water therein, it &longs;hall become &longs;o grave, that it &longs;hall &longs;ink | |
| <lb/>to the Bottom, and that by rea&longs;on of the new weight added thereto. | |
| <lb/></s><s>To this I will return an&longs;wer, as above, that the Gravity of the | |
| <lb/>Water, contained in the Ve&longs;&longs;el is not that which &longs;inks it to the Bot­ | |
| <lb/>tom, but the proper Gravity of the Bra&longs;s, &longs;uperiour to the Specificall | |
| <lb/><arrow.to.target n="marg1478"></arrow.to.target> | |
| <lb/>Gravity of the Water: for if the Ve&longs;&longs;el were le&longs;s grave than | |
| <lb/>water, the Ocean would not &longs;uffice to &longs;ubmerge it. </s><s>And, give me | |
| <lb/>leave to repeat it again, as the fundamentall and principall point in | |
| <lb/>this Ca&longs;e, that the Air contained in this Ve&longs;&longs;el before the infu&longs;ion of | |
| <lb/>the Water, was that which kept it a-float, &longs;ince that there was made | |
| <lb/><arrow.to.target n="marg1479"></arrow.to.target> | |
| <lb/>of it, and of the Bra&longs;s, a Compo&longs;ition le&longs;s grave than an equall quanti­ | |
| <lb/>ty of Water: and the place that the Ve&longs;&longs;el occupyeth in the | |
| <lb/>Water whil&longs;t it floats, is not equall to the Bra&longs;s alone, but to the | |
| <lb/>Bra&longs;s and to the Air together, which filleth that part of the Ve&longs;&longs;el | |
| <lb/>that is below the Levell of the water: Moreover, when the Water | |
| <lb/>is infu&longs;ed, the Air is removed, and there is a compo&longs;ition made of | |
| <lb/>Bra&longs;s and of water, more grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than the &longs;imple water, but | |
| <lb/>not by vertue of the water infu&longs;ed, as having greater Specifick | |
| <lb/>Gravity than the other water, but through the proper Gravity of | |
| <lb/>the Bra&longs;s, and through the alienation of the Air. </s><s>Now, as he that | |
| <lb/>&longs;hould &longs;ay that Bra&longs;s, that by its nature goes to the Bottom, being | |
| <lb/><arrow.to.target n="marg1480"></arrow.to.target> | |
| <lb/>formed into the Figure of a Ketle, acquireth from that Figure a | |
| <lb/>vertue of lying in the Water without &longs;inking, would &longs;ay that which | |
| <lb/>is fal&longs;e; becau&longs;e that Bra&longs;s fa&longs;hioned into any whatever Figure, | |
| <lb/>goeth always to the Bottom, provided, that that which is put into the | |
| <lb/>water be &longs;imple Bra&longs;s; and it is not the Figure of the Ve&longs;&longs;el that | |
| <lb/>makes the Bra&longs;s to float, but it is becau&longs;e that that is not purely | |
| <lb/>Bra&longs;s which is put into the water, but an aggregate of Bra&longs;s and of | |
| <lb/>Air: &longs;o is it neither more nor le&longs;s fal&longs;e, that a thin Plate of Bra&longs;s | |
| | |
| | |
| <pb pagenum="438"/>or of Ebony, &longs;wims by vertue of its dilated & broad Figure: for the | |
| <lb/>truth is, that it bares up without &longs;ubmerging, becau&longs;e that that which | |
| <lb/>is put in the water, is not pure Bra&longs;s or &longs;imple Ebony, but an ag­ | |
| <lb/>gregate of Bra&longs;s and Air, or of Ebony and Air. </s><s>And, this is not | |
| <lb/>contrary unto my Conclu&longs;ion, the which, (having many a time &longs;een | |
| <lb/>Ve&longs;&longs;els of Mettall, and thin pieces of diver&longs;e grave Matters float, by | |
| <lb/>vertue of the Air conjoyned with them) did affirm, That Figure | |
| <lb/>was not the Cau&longs;e of the Natation or Submer&longs;ion of &longs;uch Solids as | |
| <lb/>were placed in the water. </s><s>Nay more, I cannot omit, but mu&longs;t tell | |
| <lb/>my Antagoni&longs;ts, that this new conceit of denying that the Superfi­ | |
| <lb/>cies of the Board &longs;hould be bathed, may beget in a third per&longs;on an | |
| <lb/>opinion of a poverty of Arguments of defence on their part, &longs;ince | |
| <lb/>that &longs;uch bathing was never in&longs;i&longs;ted upon by them in the beginning | |
| <lb/>of our Di&longs;pute, and was not que&longs;tioned in the lea&longs;t, being that the | |
| <lb/>Originall of the di&longs;cour&longs;e aro&longs;e upon the &longs;wiming of Flakes of Ice, | |
| <lb/>wherein it would be &longs;implicity to require that their Superficies might | |
| <lb/>bedry: be&longs;ides, that whether the&longs;e pieces of Ice be wet or dry they | |
| <lb/>alwayes &longs;wim, and as the Adver&longs;aries &longs;ay, by rea&longs;on of the Figure. </s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1475"></margin.target>Water hath | |
| <lb/>no Gravity in | |
| <lb/>Water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1476"></margin.target>Water de­ | |
| <lb/>mini&longs;heth the | |
| <lb/>Gravity of So­ | |
| <lb/>lids immerged | |
| <lb/>therein.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1477"></margin.target>The Experi­ | |
| <lb/>ment of a Bra&longs;s | |
| <lb/>Ketle &longs;wiming | |
| <lb/>when empty, & | |
| <lb/>&longs;inking when | |
| <lb/>full, alledged to | |
| <lb/>prove that water | |
| <lb/>gravitates in | |
| <lb/>water, an&longs;wered.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1478"></margin.target>An Ocean &longs;uf­ | |
| <lb/>ficeth not to | |
| <lb/>&longs;ink a Ve&longs;&longs;el &longs;pe­ | |
| <lb/>cifically le&longs;s | |
| <lb/>grave than wa­ | |
| <lb/>ter.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1479"></margin.target>Air, the Cau&longs;e | |
| <lb/>of the Natation | |
| <lb/>of empty Ve&longs;&longs;els | |
| <lb/>of Matters gra­ | |
| <lb/>ver <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than | |
| <lb/>the water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1480"></margin.target>Neither Figure, | |
| <lb/>nor the breadth | |
| <lb/>of Figure, is the | |
| <lb/>Cau&longs;e of Nata­ | |
| <lb/>tion.</s></p><p type="main"> | |
| | |
| <s>Some peradventure, by way of defence, may &longs;ay, that wetting the | |
| <lb/>Board of Ebony, and that in the &longs;uperiour Superficies, it would, | |
| <lb/>though of it &longs;elf unable to pierce and penetrate the water, be born | |
| <lb/>downwards, if not by the weight of the additionall water, at lea&longs;t | |
| <lb/>by that de&longs;ire and propen&longs;ion that the &longs;uperiour parts of the water | |
| <lb/>have to re-unite and rejoyn them&longs;elves: by the Motion of which | |
| <lb/>parts, the &longs;aid Board cometh in a certain manner, to be depre&longs;&longs;ed | |
| <lb/>downwards. | |
| <lb/><arrow.to.target n="marg1481"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1481"></margin.target>The Bathed | |
| <lb/>Solid de&longs;cends | |
| <lb/>not out of any | |
| <lb/>affectation of u­ | |
| <lb/>nion in the upper | |
| <lb/>parts of the wa­ | |
| <lb/>ter.</s></p><p type="main"> | |
| | |
| <s>This weak Refuge will be removed, if we do but con&longs;ider, that | |
| <lb/>the repugnancy of the inferiour parts of the water, is as great against | |
| <lb/>Di&longs;-union, as the Inclination of its &longs;uperiour parts is to union: nor can | |
| <lb/>the uper unite them&longs;elves without depre&longs;&longs;ing the board, nor can it | |
| <lb/>de&longs;cend without di&longs;uniting the parts of the nether Water: &longs;o that | |
| <lb/>it doth follow, by nece&longs;&longs;ary con&longs;equence, that for tho&longs;e re&longs;pects, it &longs;hall | |
| <lb/>not de&longs;cend. </s><s>Moreover, the &longs;ame that may be &longs;aid of the upper | |
| <lb/>parts of the water, may with equall rea&longs;on be &longs;aid of the nethe, | |
| <lb/>namely, that de&longs;iring to unite, they &longs;hall force the &longs;aid Board | |
| <lb/>upwards.</s></p><p type="main"> | |
| | |
| <s>Happily, &longs;ome of the&longs;e Gentlemen that di&longs;&longs;ent from me, will won­ | |
| <lb/>der, that I affirm, that the contiguous &longs;uperiour Air is able to &longs;u&longs;tain | |
| <lb/>that Plate of <emph type="italics"/>B<emph.end type="italics"/>ra&longs;s or of Silver, that &longs;tayeth above water; as if I | |
| <lb/><arrow.to.target n="marg1482"></arrow.to.target> | |
| <lb/>would in a certain &longs;ence allow the Air, a kind of Magnetick vertue | |
| <lb/>of &longs;u&longs;taining the grave <emph type="italics"/>B<emph.end type="italics"/>odies, with which it is contiguous. </s><s>To &longs;a­ | |
| <lb/>tis&longs;ie all I may, to all doubts, I have been con&longs;idering how by &longs;ome | |
| <lb/>other &longs;en&longs;ible Experiment I might demon&longs;trate, how truly that little | |
| <lb/>contiguous and &longs;uperiour Air &longs;u&longs;taines tho&longs;e Solids, which being by | |
| | |
| | |
| <pb pagenum="439"/>nature apt to de&longs;cend to the Bottom, being placed lightly on the water | |
| <lb/>&longs;ubmerge not, unle&longs;s they be fir&longs;t thorowly bathed; and have found, | |
| <lb/>that one of the&longs;e Bodies having de&longs;cended to the Bottom, by conveigh­ | |
| <lb/>ing to it (without touching it in the lea&longs;t) a little Air, which conjoyneth | |
| <lb/>with the top of the &longs;ame; it becometh &longs;ufficient, not only, as before to | |
| <lb/>&longs;u&longs;tain it, but al&longs;o to rai&longs;e it, and to carry it back to the top, where it | |
| <lb/>&longs;tays and abideth in the &longs;ame manner, till &longs;uch time, as the a&longs;&longs;i&longs;tance | |
| <lb/>of the conjoyned Air is taken away. </s><s>And to this effect, I have taken a | |
| <lb/>Ball of Wax, and made it with a little Lead, &longs;o grave, that it lea&longs;urely | |
| <lb/>de&longs;cends to the Bottom, making with all its Superficies very &longs;mooth and | |
| <lb/>pollite: and this being put gently into the water, almo&longs;t wholly &longs;ub­ | |
| <lb/><arrow.to.target n="marg1483"></arrow.to.target> | |
| <lb/>mergeth, there remaining vi&longs;&longs;ible only a little of the very top, the which | |
| <lb/>solong as it is conjoyned with the Air, &longs;hall retain the Ball a-top, but | |
| <lb/>the Contiguity of the Air taken away by wetting it, it &longs;hall de&longs;cend to | |
| <lb/>the Bottom and there remain. </s><s>Now to make it by vertue of the Air, that | |
| <lb/>before &longs;u&longs;tained it to return again to the top, and &longs;tay there, thru&longs;t into | |
| <lb/>the water a Gla&longs;s rever&longs;ed with the mouth downwards, the which &longs;hall | |
| <lb/>carry with it the Air it contains, and move this towards the Ball, aba&longs;ing | |
| <lb/>it till &longs;uch time that you &longs;ee, by the tran&longs;parency of the Gla&longs;s, that the | |
| <lb/><arrow.to.target n="marg1484"></arrow.to.target> | |
| <lb/>contained Air do arrive to the &longs;ummity of the <emph type="italics"/>B<emph.end type="italics"/>all: then gently with­ | |
| <lb/>draw the Gla&longs;s upwards, and you &longs;hall &longs;ee the <emph type="italics"/>B<emph.end type="italics"/>all to ri&longs;e, and afterwards | |
| <lb/><arrow.to.target n="marg1485"></arrow.to.target> | |
| <lb/>stay on the top of the water, if you carefully part the Gla&longs;s and the water | |
| <lb/>without overmuch commoving and di&longs;turbing it. </s><s>There is, therefore, a | |
| <lb/>certain affinity between the Air and other <emph type="italics"/>B<emph.end type="italics"/>odies, which holds them uni­ | |
| <lb/>ed, &longs;o, that they &longs;eperate not without a kind of violence. </s><s>The &longs;ame | |
| <lb/><arrow.to.target n="marg1486"></arrow.to.target> | |
| <lb/>likewi&longs;e is &longs;een in the water; for if we &longs;hall wholly &longs;ubmerge &longs;ome <emph type="italics"/>B<emph.end type="italics"/>ody | |
| <lb/>in it, &longs;o that it be thorowly bathed, in the drawing of it afterwards gent­ | |
| <lb/>ly out again, we &longs;hall &longs;ee the water follow it, and ri&longs;e notably above its | |
| <lb/>Surface, before it &longs;eperates from it. </s><s>Solid <emph type="italics"/>B<emph.end type="italics"/>odies, al&longs;o, if they be equall | |
| <lb/><arrow.to.target n="marg1487"></arrow.to.target> | |
| <lb/>and alike in Superficies, &longs;o, that they make an exact Contact without | |
| <lb/>the interpo&longs;ition of the lea&longs;t Air, that may part them in the &longs;eperation | |
| <lb/>and yield untill that the ambient <emph type="italics"/>Medium<emph.end type="italics"/> &longs;ucceeds to repleni&longs;h the place, | |
| <lb/>do hold very firmly conjoyned, and are not to be &longs;eperated without great | |
| <lb/>force but, becau&longs;e, the Air, Water, and other Liquids, very expedi­ | |
| <lb/>tiou&longs;ly &longs;hape them&longs;elves to contact with any Solid <emph type="italics"/>B<emph.end type="italics"/>odies, &longs;o that their | |
| <lb/>Superficies do exqui&longs;itely adopt them&longs;elves to that of the Solids, without | |
| <lb/>any thing remaining between them, therefore, the effect of this Con­ | |
| <lb/>junction and Adherence is more manife&longs;tly and frequently ob&longs;erved in | |
| <lb/>them, than in hard and inflexible <emph type="italics"/>B<emph.end type="italics"/>odies, who&longs;e Superficies do very rate­ | |
| <lb/>ly conjoyn with exactne&longs;s of Contact. </s><s>This is therefore that Magne­ | |
| <lb/><arrow.to.target n="marg1488"></arrow.to.target> | |
| <lb/>tick vertue, which with firm Connection conjoyneth all Bodies, that do | |
| <lb/>touch without the interpo&longs;ition of flexible fluids; and, who knows, but | |
| <lb/>that that a Contact, when it is very exact, may be a &longs;ufficient Cau&longs;e of | |
| <lb/>the Union and Continuity of the parts of a naturall <emph type="italics"/>B<emph.end type="italics"/>ody?</s></p> | |
| | |
| | |
| <pb pagenum="440"/><p type="margin"> | |
| | |
| <s><margin.target id="marg1482"></margin.target><emph type="italics"/>A<emph.end type="italics"/> Magneti&longs;me in | |
| <lb/>the <emph type="italics"/>A<emph.end type="italics"/>ir, by which | |
| <lb/>it bears up tho&longs;e | |
| <lb/>Solids in the wa­ | |
| <lb/>ter, that are con­ | |
| <lb/>tiguous with it.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1483"></margin.target>The Effect of | |
| <lb/>the Airs Conti­ | |
| <lb/>guity in the Na­ | |
| <lb/>tation of Solids.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1484"></margin.target>The force of | |
| <lb/>Contact.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1485"></margin.target><emph type="italics"/>A<emph.end type="italics"/>n affectati­ | |
| <lb/>on of Conjunct­ | |
| <lb/>ion betwixt So­ | |
| <lb/>lids and the Air | |
| <lb/>contiguous to | |
| <lb/>them.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1486"></margin.target>The like affect­ | |
| <lb/>ation of Con­ | |
| <lb/>junction be­ | |
| <lb/>twixt Solids & | |
| <lb/>the water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1487"></margin.target>Al&longs;o the like | |
| <lb/>affectation and | |
| <lb/>Conjunction be­ | |
| <lb/>twixt Solids | |
| <lb/>them&longs;eives.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1488"></margin.target>Contact may | |
| <lb/>be the Cau&longs;e of | |
| <lb/>the Continuity | |
| <lb/>of Naturall Bo­ | |
| <lb/>dies.</s></p><p type="main"> | |
| | |
| <s>Now, pur&longs;uing my purpo&longs;e, I &longs;ay; that it needs not, that we have | |
| <lb/>recour&longs;e to the Tenacity, that the parts of the water have among&longs;t them­ | |
| <lb/>&longs;elves, by which they re&longs;i&longs;t and oppo&longs;e Divi&longs;ion, Di&longs;traction, and Seper­ | |
| <lb/>ration, becau&longs;e there is no &longs;uch Coherence and Re&longs;i&longs;tance of Divi&longs;ion | |
| <lb/>for if there were, it would be no le&longs;s in the internall parts than in tho&longs;e | |
| <lb/>nearer the &longs;uperiour or externall Surface, &longs;o that the &longs;ame Board, find­ | |
| <lb/>ing alwayes the &longs;ame Re&longs;i&longs;tance and Renitence, would no le&longs;s &longs;top in | |
| <lb/>the middle of the water than about the Surface, which is fal&longs;e. More­ | |
| <lb/></s><s>over, what Re&longs;i&longs;tance can we place in the Continuity of the water | |
| <lb/>if we &longs;ee that it is impo&longs;&longs;ible to &longs;ind any Body of what&longs;oever Matter | |
| <lb/>Figure or Magnitude, which being put into the water, &longs;hall be ob&longs;tructed | |
| <lb/>and impeded by the Tenacity of the parts of the water to one another | |
| <lb/>&longs;o, but that it is moved upwards or downwards, according as the Cau&longs;e | |
| <lb/>of their Motion tran&longs;ports it? </s><s>And, what greater proof of it can we de­ | |
| <lb/>&longs;ier, than that which we daily &longs;ee in Muddy waters, which being put into | |
| <lb/>Ve&longs;&longs;els to be drunk, and being, after &longs;ome hours &longs;etling, &longs;till, as we &longs;ay | |
| <lb/><arrow.to.target n="marg1489"></arrow.to.target> | |
| <lb/>thick in the end, after four or &longs;ix dayes they are wholly &longs;etled, and be­ | |
| <lb/>come pure and clear? </s><s>Nor can their Re&longs;i&longs;tance of Penetration &longs;tay tho&longs;e | |
| <lb/>impalpable and in&longs;en&longs;ible Atomes of Sand, which by rea&longs;on of their | |
| <lb/>exceeding &longs;mall force, &longs;pend &longs;ix dayes in de&longs;cending the &longs;pace of half | |
| <lb/>a yard.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1489"></margin.target><emph type="italics"/>T<emph.end type="italics"/>he &longs;ettlement | |
| <lb/>of <emph type="italics"/>M<emph.end type="italics"/>uddy Wa­ | |
| <lb/>ter, proveth that | |
| <lb/>that Element | |
| <lb/>hath no aver&longs;i­ | |
| <lb/>on to Divi&longs;ion.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Nor let them &longs;ay, that the &longs;eeing of &longs;uch &longs;mall Bodies, con&longs;ume &longs;ix dayes in | |
| <lb/>de&longs;cending &longs;o little a way, is a &longs;ufficient Argument of the Waters Re&longs;i&longs;tance | |
| <lb/>of Divi&longs;ion; becau&longs;e that is no re&longs;i&longs;ting of Divi&longs;ion, but a retarding of<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1490"></arrow.to.target> | |
| <lb/><emph type="italics"/>Motion; and it would be &longs;implicity to &longs;ay, that a thing oppo&longs;eth Divi&longs;ion | |
| <lb/>and that in the &longs;ame in&longs;tant, it permits it &longs;elf to be divided: nor doth the | |
| <lb/>Retardation of Motion at all favour the Adver&longs;aries cau&longs;e, for that they are | |
| <lb/>to in&longs;tance in a thing that wholly prohibiteth Motion, and procureth Re&longs;t; | |
| <lb/>it is nece&longs;&longs;ary, therefore, to find out Bodies that &longs;tay in the water, if one would | |
| <lb/>&longs;hew its repugnancy to Divi&longs;ion, and not &longs;uch as move in it, howbeit | |
| <lb/>&longs;lowly.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1490"></margin.target>Water cannot | |
| <lb/>oppo&longs;e divi&longs;ion, | |
| <lb/>and at the &longs;ame | |
| <lb/>time permit it | |
| <lb/>&longs;elf to be divi­ | |
| <lb/>ded.</s></p><p type="main"> | |
| | |
| <s>What then is this Cra&longs;&longs;itude of the water, with which it re&longs;i&longs;teth Di­ | |
| <lb/>vi&longs;ion? </s><s>What, I be&longs;eech you, &longs;hould it be, if we (as we have &longs;aid above) | |
| <lb/>with all diligence attempting the reduction of a Matter into &longs;o like a | |
| <lb/>Gravity with the water, that forming it into a dilated Plate it re&longs;ts &longs;u&longs;­ | |
| <lb/>pended as we have &longs;aid, between the two waters, it be impo&longs;&longs;ible to | |
| <lb/>effect it, though we bring them to &longs;uch an Equiponderance, that as | |
| <lb/>much Lead as the fourth part of a Grain of Mu&longs;terd-&longs;eed, added to the | |
| <lb/>&longs;ame expanded Plate, that in Air [<emph type="italics"/>i. </s><s>e. </s><s>out of the water<emph.end type="italics"/>] &longs;hall weigh four | |
| <lb/>or fix pounds, &longs;inketh it to the Bottom, and being &longs;ub&longs;tracted, it a&longs;cends | |
| <lb/>to the Surface of the water? </s><s>I cannot &longs;ee, (if what I &longs;ay be true, as it is | |
| <lb/>mo&longs;t certain) what minute vertue and force we can po&longs;&longs;ibly find or ima­ | |
| <lb/>gine, to which the Re&longs;i&longs;tance of the water again&longs;t Divi&longs;ion and Penetra­ | |
| | |
| | |
| <pb pagenum="441"/>tion is not inferiour; whereupon, we mu&longs;t of nece&longs;&longs;ity conclude | |
| <lb/>that it is nothing: becan&longs;e, if it were of any &longs;en&longs;ible power, &longs;ome | |
| <lb/>large Plate might be found or compounded of a Matter alike in Gra­ | |
| <lb/>vity to the water, which not only would &longs;tay between the two wa­ | |
| <lb/>ters; but, moreover, &longs;hould not be able to de&longs;cend or a&longs;cend with­ | |
| <lb/>out notable force. </s><s>We may likewi&longs;e collect the &longs;ame from an o­ | |
| <lb/><arrow.to.target n="marg1491"></arrow.to.target> | |
| <lb/>ther Experiment, &longs;hewing that the Water gives way al&longs;o in the &longs;ame | |
| <lb/>manner to tran&longs;ver&longs;all Divi&longs;ion; for if in a &longs;etled and &longs;tanding water | |
| <lb/>we &longs;hould place any great Ma&longs;s that goeth not to the bottom, draw­ | |
| <lb/>ing it with a &longs;ingle (Womans) Hair, we might carry it from place to | |
| <lb/>place without any oppo&longs;ition, and this whatever Figure it hath, | |
| <lb/>though that it po&longs;&longs;e&longs;s a great &longs;pace of water, as for in&longs;tance, a great | |
| <lb/>Beam would do moved &longs;ide-ways. </s><s>Perhaps &longs;ome might oppo&longs;e me | |
| <lb/>and &longs;ay, that if the Re&longs;i&longs;tance of water again&longs;t Divi&longs;ion, as I affirm, | |
| <lb/>were nothing; Ships &longs;hould not need &longs;uch a force of Oars and Sayles | |
| <lb/>for the moving of them from place to place in a tranquile Sea, or | |
| <lb/>&longs;tanding Lake. </s><s>To him that &longs;hould make &longs;uch an objection, I would | |
| <lb/><arrow.to.target n="marg1492"></arrow.to.target> | |
| <lb/>reply, that the water contra&longs;teth not again&longs;t, nor &longs;imply re&longs;i&longs;teth | |
| <lb/>Divi&longs;ion, but a &longs;udden Divi&longs;ion, and with &longs;o much greater Reni­ | |
| <lb/>tence, by how much greater the Velocity is: and the Cau&longs;e of this | |
| <lb/>Re&longs;i&longs;tance depends not on Cra&longs;&longs;itude, or any other thing that ab&longs;o­ | |
| <lb/>lutely oppo&longs;eth Divi&longs;ion, but becau&longs;e that the parts of the water | |
| <lb/>divided, in giving way to that Solid that is moved in it, are them­ | |
| <lb/>&longs;elves al&longs;o nece&longs;&longs;itated locally to move, &longs;ome to the one &longs;ide, and &longs;ome | |
| <lb/>to the other, and &longs;ome downwards: and this mu&longs;t no le&longs;s be done | |
| <lb/>by the waves before the Ship, or other Body &longs;wimming through the | |
| <lb/>water, than by the po&longs;teriour and &longs;ub&longs;equent; becau&longs;e, the Ship | |
| <lb/>proceeding forwards, to make it &longs;elf a way to receive its Bulk, it is | |
| <lb/>requi&longs;ite, that with the Prow it repul&longs;e the adjacent parts of the | |
| <lb/>water, as well on one hand as on the other, and that it move them | |
| <lb/>as much tran&longs;ver&longs;ly, as is the half of the breadth of the Hull: and | |
| <lb/>the like removall mu&longs;t tho&longs;e waves make, that &longs;ucceeding the Poump | |
| <lb/>do run from the remoter parts of the Ship towards tho&longs;e of the | |
| <lb/>middle, &longs;ucce&longs;&longs;ively to repleni&longs;h the places, which the Ship in ad­ | |
| <lb/>vancing forwards, goeth, leaving vacant. </s><s>Now, becau&longs;e, all Moti­ | |
| <lb/><arrow.to.target n="marg1493"></arrow.to.target> | |
| <lb/>tions are made in Time, and the longer in greater time: and it being | |
| <lb/>moreover true, that tho&longs;e Bodies that in a certain time are moved | |
| <lb/>by a certain power &longs;uch a certain &longs;pace, &longs;hall not be moved the &longs;ame | |
| <lb/>&longs;pace, and in a &longs;horter Time, unle&longs;s by a greater Power: therefore, | |
| <lb/>the broader Ships move &longs;lower than the narrower, being put on by | |
| <lb/>an equall Force: and the &longs;ame Ve&longs;&longs;el requires &longs;o much greater | |
| <lb/>force of Wind, or Oars, the fa&longs;ter it is to move.</s></p> | |
| | |
| | |
| <pb pagenum="442"/><p type="margin"> | |
| | |
| <s><margin.target id="marg1491"></margin.target>An hair will | |
| <lb/>draw a great | |
| <lb/>Ma&longs;s thorow the | |
| <lb/>Water; which | |
| <lb/>proveth, that it | |
| <lb/>hath no Re&longs;i&longs;t­ | |
| <lb/>ance again&longs;t | |
| <lb/>tran&longs;ver&longs;all Di­ | |
| <lb/>vi&longs;ion.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1492"></margin.target>How &longs;hips are | |
| <lb/>moved in the | |
| <lb/>water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1493"></margin.target>Bodies moved | |
| <lb/>a certain &longs;pace in | |
| <lb/>a certain Time, | |
| <lb/>by a certain | |
| <lb/>power, cannot be | |
| <lb/>moved the | |
| <lb/>&longs;ame &longs;pace, and | |
| <lb/>in a &longs;horter time, | |
| <lb/>but by a greater | |
| <lb/>power.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>But yet for all this, any great Ma&longs;s &longs;wimming in a &longs;tanding Lake, may | |
| <lb/>be moved by any petit force; only it is true, that a le&longs;&longs;er force more | |
| <lb/>&longs;lowly moves it: but if the waters Re&longs;i&longs;tance of Divi&longs;ion, were in any | |
| <lb/>manner &longs;en&longs;ible, it would follow, that the &longs;aid Ma&longs;s, &longs;hould, notwith­ | |
| <lb/>&longs;tanding the percu&longs;&longs;ion of &longs;ome &longs;en&longs;ible force, continue immoveable, which is<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1494"></arrow.to.target> | |
| <lb/><emph type="italics"/>not &longs;o. </s><s>Yea, I will &longs;ay farther, that &longs;hould we retire our &longs;elves into the | |
| <lb/>more internall contemplation of the Nature of water and other Fluids, | |
| <lb/>perhaps we &longs;hould di&longs;cover the Con&longs;titution of their parts to be &longs;uch, that | |
| <lb/>they not only do not oppo&longs;e Divi&longs;ion, but that they have not any thing in | |
| <lb/>them to be divided: &longs;o that the Re&longs;i&longs;tance that is ob&longs;erved in moving<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1495"></arrow.to.target> | |
| <lb/><emph type="italics"/>through the water, is like to that which we meet with in pa&longs;&longs;ing through | |
| <lb/>a great Throng of People, wherein we find impediment, and not by any | |
| <lb/>difficulty in the Divi&longs;ion, for that none of tho&longs;e per&longs;ons are divided | |
| <lb/>whereof the Croud is compo&longs;ed, but only in moving of tho&longs;e per&longs;ons &longs;ide­ | |
| <lb/>ways which were before divided and disjoyned: and thus we find | |
| <lb/>Re&longs;i&longs;tance in thru&longs;ting a Stick into an heap of Sand, not becau&longs;e any part | |
| <lb/>of the Sand is to be cut in pieces, but only to be moved and rai&longs;ed. two <emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1496"></arrow.to.target> | |
| <lb/><emph type="italics"/>manners of Penetration, therefore, offer them&longs;elves to us, one in Bodies, | |
| <lb/>who&longs;e parts were continuall, and here Divi&longs;ion &longs;eemeth nece&longs;&longs;ary; the <emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1497"></arrow.to.target> | |
| <lb/><emph type="italics"/>other in the aggregates of parts not continuall, but contiguous only, and | |
| <lb/>here there is no nece&longs;&longs;ity of dividing but of moving only. </s><s>Now, I am | |
| <lb/>not well re&longs;olved, whether water and other Fluids may be e&longs;teemed to | |
| <lb/>be of parts continuall or contiguous only; yet I find my &longs;elf indeed incli­<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1498"></arrow.to.target> | |
| <lb/><emph type="italics"/>ned to think that they are rather contiguous (if there be in Naturno | |
| <lb/>other manner of aggregating, than by the union, or by the touching of the | |
| <lb/>extreams:) and I am induced thereto by the great difference that I &longs;ee > | |
| <lb/>between the Conjunction of the parts of an hard or Solid Body, and the<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1499"></arrow.to.target> | |
| <lb/><emph type="italics"/>Conjunction of the &longs;ame parts when the &longs;ame Body &longs;hall be made Liquid | |
| <lb/>and Fluid: for if, for example, I take a Ma&longs;s of Silver or other Solid | |
| <lb/>and hard Mettall, I &longs;hall in dividing it into two parts, find not only the <emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1500"></arrow.to.target> | |
| <lb/><emph type="italics"/>re&longs;i&longs;tance that is found in the moving of it only, but an other incomparably | |
| <lb/>greater, dependent on that vertue, whatever it be, which holds the parts | |
| <lb/>united: and &longs;o if we would divide again tho&longs;e two parts into other two | |
| <lb/>and &longs;ucce&longs;&longs;ively into others and others, we &longs;hould &longs;till find a like Re&longs;i&longs;t­ | |
| <lb/>ance, but ever le&longs;s by how much &longs;maller the parts to be divided &longs;hall be; | |
| <lb/>but if, la&longs;tly, employing mo&longs;t &longs;ubtile and acute In&longs;truments, &longs;uch as are | |
| <lb/>the mo&longs;t tenuous parts of the Fire, we &longs;hall re&longs;olve it (perhaps) into its | |
| <lb/>la&longs;t and lea&longs;t Particles, there &longs;hall not be left in them any longer either | |
| <lb/>Re&longs;i&longs;tance of Divi&longs;ion, or &longs;o much as a capacity of being farther divi­ | |
| <lb/>ded, e&longs;pecially by In&longs;truments more gro&longs;&longs;e than the acuities of Fire: and | |
| <lb/>what Knife or Ra&longs;or put into well melted Silver can we finde, that will | |
| <lb/>divide a thing which &longs;urpa&longs;&longs;eth the &longs;eparating power of Fire? </s><s>Certainly | |
| <lb/>none: becau&longs;e either the whole &longs;hall be reduced to the mo&longs;t minute and | |
| <lb/>ultimate Divi&longs;ions, or if there remain parts capable &longs;till of other Suddi­<emph.end type="italics"/> | |
| | |
| | |
| <pb pagenum="443"/><emph type="italics"/>divi&longs;ions, they cannot receive them, but only from acuter Divi&longs;ors than | |
| <lb/>Fire; but a Stick or Rod of Iron, moved in the melted Met all, is not | |
| <lb/>&longs;uch a one. </s><s>Of a like Con&longs;titution and Con&longs;i&longs;tence, I account the parts<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1501"></arrow.to.target> | |
| <lb/><emph type="italics"/>of Water, and other Liquids to be, namely, incapable of Divi&longs;ion by | |
| <lb/>rea&longs;on of their Temtity; or if not ab&longs;olutely indivi&longs;ible, yet at lea&longs;t | |
| <lb/>not to be divided by a Board, or other Solid Body, palpable unto the | |
| <lb/>band, the Sector being alwayes required to be more &longs;harp than the Solid | |
| <lb/>to be cut. </s><s>Solid Bodies, therefore, do only move, and not divide the<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1502"></arrow.to.target> | |
| <lb/><emph type="italics"/>Water, when put into it; who&longs;e parts being before divided to the ex­ | |
| <lb/>treame&longs;t minuity, and therefore capable of being moved, either many of | |
| <lb/>them at once, or few, or very few, they &longs;oon give place to every &longs;mall Cor­ | |
| <lb/>pu&longs;cle, that de&longs;cends in the &longs;ame: for that, it being little and light, de­ | |
| <lb/>&longs;cending in the Air, and arriving to the Surface of the Water, it meets | |
| <lb/>with Particles of Water more &longs;mall, and of le&longs;s Re&longs;i&longs;tance again&longs;t | |
| <lb/>Motion and Extru&longs;ion, than is its own prement and extru&longs;ive force, | |
| <lb/>whereupon it &longs;ubmergeth, and moveth &longs;uch a portion of them, as is pro­ | |
| <lb/>portionate to its Power. </s><s>There is not, therefore, any Re&longs;i&longs;tance in | |
| <lb/>Water again&longs;t Divi&longs;ion, nay, there is not in it any divi&longs;ible parts. </s><s>I | |
| <lb/>adde, moreover, that in ca&longs;e yet there &longs;bould be any &longs;mall Re&longs;i&longs;tance<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1503"></arrow.to.target> | |
| <lb/><emph type="italics"/>found (which is ab&longs;olutely fal&longs;e) haply in attempting with an Hair to | |
| <lb/>move a very great natant Machine, or in e&longs;&longs;aying by the addition of one | |
| <lb/>&longs;mall Grain of Lead to &longs;ink, or by removall of it to rai&longs;e a very broad | |
| <lb/>Plate of Matter, equall in Gravity with Water, (which likewi&longs;e will | |
| <lb/>not happen, in ca&longs;e we proceed with dexterity) we may ob&longs;erve that that | |
| <lb/>Re&longs;i&longs;tance is a very different thing from that which the Adver&longs;aries pro­ | |
| <lb/>duce for the Cau&longs;e of the Natation of the Plate of Lead or Board of Ebo­ | |
| <lb/>ny, for that one may make a Board of Ebony, which being put upon the | |
| <lb/>Water &longs;wimmeth, and cannot be &longs;ubmerged, no not by the addition of an | |
| <lb/>bundred Grains of Lead put upon the &longs;ame, and afterwards being ba­ | |
| <lb/>thed, not only &longs;inks, though the &longs;aid Lead be taken away, but though | |
| <lb/>moreover a quantity of Cork, or of &longs;ome other light Body fa&longs;tened to it, | |
| <lb/>&longs;ufficeth not to hinder it from &longs;inking unto the bottome: &longs;o that you | |
| <lb/>&longs;ee, that although it were granted that there is a certain &longs;mall Re&longs;i&longs;t­ | |
| <lb/>ance of Divi&longs;ion found in the &longs;ubstance of the Water, yet this hath no­ | |
| <lb/>thing to do with that Cau&longs;e which &longs;upports the Board above the Water, | |
| <lb/>with a Re&longs;i&longs;tance an hundred times greater than that which men can | |
| <lb/>find in the parts of the Water: nor let them tell me, that only the Sur-<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1504"></arrow.to.target> | |
| <lb/><emph type="italics"/>face of the Water hath &longs;uch Re&longs;i&longs;tance, and not the internall parts, or | |
| <lb/>that &longs;uch Re&longs;i&longs;tance is found greate&longs;t in the beginning of the Submer&longs;ion, | |
| <lb/>as it al&longs;o &longs;eems that in the beginning, Motion meets with greater oppo&longs;iti­ | |
| <lb/>on, than in the continuance of it; becau&longs;e, fir&longs;t, I will permit, that the<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1505"></arrow.to.target> | |
| <lb/><emph type="italics"/>Water be &longs;tirred, and that the &longs;uperiour parts be mingled with the mid­ | |
| <lb/>dle, and inferiour parts, or that tho&longs;e above be wholly removed, and | |
| <lb/>tho&longs;e in the middle only made u&longs;e off, and yet you &longs;hall &longs;ee the effect for<emph.end type="italics"/> | |
| | |
| | |
| <pb pagenum="444"/><emph type="italics"/>all that, to be still the &longs;ame: Moreover, that Hair which draws a | |
| <lb/>Beam through the Water, is likewi&longs;e to divide the upperparts, and is | |
| <lb/>al&longs;o to begin the Motion, and yet it begins it, and yet it divides it: and | |
| <lb/>finally, let the Board of Ebony be put in the midway, betwixt the bottome | |
| <lb/>and the top of the Water, and let it there for a while be &longs;u&longs;pended and | |
| <lb/>&longs;etled, and afterwards let it be left at liberty, and it will instantly begin | |
| <lb/>its Motion, and will continue it unto the bottome. </s><s>Nay, more, the Board | |
| <lb/>&longs;o &longs;oon as it is dimitted upon the Water, hath not only begun to move | |
| <lb/>and divide it, but is for a good &longs;pace dimerged into it.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1494"></margin.target>The parts of | |
| <lb/>Liquids, &longs;o farte | |
| <lb/>from re&longs;i&longs;ting | |
| <lb/>Divi&longs;ion, that | |
| <lb/>they contain not | |
| <lb/>any thing that | |
| <lb/>may be divided.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1495"></margin.target>The Re&longs;i&longs;t­ | |
| <lb/>ance a Solid | |
| <lb/>findeth in mo­ | |
| <lb/>ving through | |
| <lb/>the water, like | |
| <lb/>to that we meet | |
| <lb/>with in pa&longs;&longs;ing | |
| <lb/>through a | |
| <lb/>throng of peo­ | |
| <lb/>ple;</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1496"></margin.target>Or in thru&longs;t­ | |
| <lb/>ing a Stick into | |
| <lb/>an heap of Sand.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1497"></margin.target>Two kinds of | |
| <lb/>Penetration, one | |
| <lb/>in Bodies conti­ | |
| <lb/>nuall, the other | |
| <lb/>in Bodies only | |
| <lb/>contiguous.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1498"></margin.target>Water con&longs;i&longs;ts | |
| <lb/>not of continu­ | |
| <lb/>all, but only | |
| <lb/>of contiguous | |
| <lb/>parts.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1499"></margin.target><emph type="italics"/>Set what &longs;atis­ | |
| <lb/>faction he hath | |
| <lb/>given, as to this | |
| <lb/>point, in Lib. de | |
| <lb/>Motu. </s><s>Dial.<emph.end type="italics"/> 2.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1500"></margin.target>Great differ­ | |
| <lb/>ence betwixt the | |
| <lb/>Conjunction of | |
| <lb/>the parts of a Bo­ | |
| <lb/>dy when Solid, | |
| <lb/>and when fluid.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1501"></margin.target>Water con&longs;i&longs;ts | |
| <lb/>of parts that ad­ | |
| <lb/>mit of no fat­ | |
| <lb/>ther divi&longs;ion.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1502"></margin.target>Solids dimit­ | |
| <lb/>ted into the wa­ | |
| <lb/>ter, do onely | |
| <lb/>move, and not | |
| <lb/>divide it.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1503"></margin.target>If there were | |
| <lb/>any Re&longs;i&longs;tance | |
| <lb/>of Divi&longs;ion in | |
| <lb/>water, it mu&longs;t | |
| <lb/>needs be &longs;mall, | |
| <lb/>in that it is over­ | |
| <lb/>come by an | |
| <lb/>Hair, a Grain of | |
| <lb/>Lead, or a &longs;light | |
| <lb/>bathing of the | |
| <lb/>Solid.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1504"></margin.target>The uper parts | |
| <lb/>of the Water, do | |
| <lb/>no more re&longs;i&longs;t | |
| <lb/>Divi&longs;ion, than | |
| <lb/>the middle or | |
| <lb/>lowe&longs;t parts.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1505"></margin.target>Waters Re­ | |
| <lb/>&longs;i&longs;tance of divi­ | |
| <lb/>&longs;ion, not greater | |
| <lb/>in the begin­ | |
| <lb/>ning of the Sub­ | |
| <lb/>mer&longs;ion.</s></p><p type="main"> | |
| | |
| <s>Let us receive it, therefore, for a true and undoubted Conclu&longs;i­ | |
| <lb/>on, That the Water hath not any Renitence again&longs;t &longs;imple Divi&longs;i­ | |
| <lb/>on, and that it is not po&longs;&longs;ible to find any Solid Body, be it of what | |
| <lb/>Figure it will, which being put into the Water, its Motion upwards | |
| <lb/>or downwards, according as it exceedeth, or &longs;hall be exceeded by | |
| <lb/>the Water in Gravity (although &longs;uch exce&longs;&longs;e and difference be in­ | |
| <lb/>&longs;en&longs;ible) &longs;hall be prohibited, and taken away, by the Cra&longs;&longs;itude of | |
| <lb/>the &longs;aid Water. </s><s>When, therefore, we &longs;ee the Board of Ebony, or | |
| <lb/>of other Matter, more grave than the Water, to &longs;tay in the Con­ | |
| <lb/>fines of the Water and Air, without &longs;ubmerging, we mu&longs;t have re­ | |
| <lb/>cour&longs;e to &longs;ome other Originall, for the inve&longs;ting the Cau&longs;e of that | |
| <lb/>Effect, than to the breadth of the Figure, unable to overcome the | |
| <lb/>Renitence with which the Water oppo&longs;eth Divi&longs;ion, &longs;ince there is | |
| <lb/>no Re&longs;i&longs;tance; and from that which is not in being, we can expect | |
| <lb/>no Action. </s><s>It remains mo&longs;t true, therefore, as we have &longs;aid before, that | |
| <lb/>this &longs;o &longs;ucceds, for that that which in &longs;uch manner put upon the wa­ | |
| <lb/>ter, not the &longs;ame Body with that which is put <emph type="italics"/>into<emph.end type="italics"/> the Water: becau&longs;e | |
| <lb/>this which is put <emph type="italics"/>into<emph.end type="italics"/> the Water, is the pure Board of Ebony, which | |
| <lb/>for that it is more grave than the Water, &longs;inketh, and that which is | |
| <lb/>put <emph type="italics"/>upon<emph.end type="italics"/> the Water, is a Compo&longs;ition of Ebony, and of &longs;o much | |
| <lb/>Air, that both together are &longs;pecifically le&longs;s grave than the Water, | |
| <lb/>and therefore they do not de&longs;cend.</s></p><p type="main"> | |
| | |
| <s>I will farther confirm this which I &longs;ay. </s><s>Gentlemen, my Antago­ | |
| <lb/>ni&longs;ts, we are agreed, that the exce&longs;s or defect of the Gravity of the | |
| <lb/>Solid, unto the Gravity of the Water, is the true and proper Cau&longs;e | |
| <lb/>of Natation or Submer&longs;ion. | |
| <lb/><arrow.to.target n="marg1506"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1506"></margin.target>Great Caution | |
| <lb/>to be had in ex­ | |
| <lb/>perimenting the | |
| <lb/>operation of Fi­ | |
| <lb/>gure in Natati­ | |
| <lb/>on.</s></p><p type="main"> | |
| | |
| <s>Now, if you will &longs;hew that be&longs;ides the former Cau&longs;e, there is ano­ | |
| <lb/>ther which is &longs;o powerfull, that it can hinder and remove the Sub­ | |
| <lb/>mer&longs;ion of tho&longs;e very Solids, that by their Gravity &longs;ink, and if you | |
| <lb/>will &longs;ay, that this is the breadth or amplene&longs;s of Figure, you are ob­ | |
| <lb/>lieged, when ever you would &longs;hew &longs;uch an Experiment, fir&longs;t to make | |
| <lb/>the circum&longs;tances certain, that that Solid which you put into the | |
| <lb/>Water, be not le&longs;s grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than it, for if you &longs;hould not do &longs;o | |
| <lb/>any one might with rea&longs;on &longs;ay, that not the Figure, but the Levity | |
| <lb/>was the cau&longs;e of that Natation. </s><s>But I &longs;ay, that when you &longs;hall di­ | |
| | |
| | |
| <pb pagenum="445"/>mit a Board of Ebony into the Water, you do not put therein a Solid | |
| <lb/>more grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than the Water, but one lighter, for be &longs;ides the | |
| <lb/>Ebony, there is in the Water a Ma&longs;s of Air, united with the Ebony, | |
| <lb/>and &longs;uch, and &longs;o light, that of both there re&longs;ults a Compo&longs;ition le&longs;s | |
| <lb/>grave than the Water: See, therefore, that you remove the Air, and | |
| <lb/>put the Ebony alone into the Water, for &longs;o you &longs;hall immerge a So­ | |
| <lb/>lid more grave then the Water, and if this &longs;hall not go to the Bottom, | |
| <lb/>you have well Philo&longs;ophized, and I ill.</s></p><p type="main"> | |
| | |
| <s>Now, &longs;ince we have found the true Cau&longs;e of the Natation of tho&longs;e | |
| <lb/>Bodies, which otherwi&longs;e as being graver than the Water, would de­ | |
| <lb/>&longs;cend to the bottom, I think, that for the perfect and di&longs;tinct know­ | |
| <lb/>ledge of this bu&longs;ine&longs;s, it would be good to proceed in a way of di&longs;­ | |
| <lb/>covering demon&longs;tratively tho&longs;e particular Accidents that do attend | |
| <lb/>the&longs;e effects, and,</s></p><p type="head"> | |
| | |
| <s>PROBL. I.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>To finde what proportion &longs;everall Figures of different<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1507"></arrow.to.target> | |
| <lb/><emph type="italics"/>Matters ought to have, unto the Gravity of the | |
| <lb/>Water, that &longs;o they may be able by vertue of the | |
| <lb/>Contigucus Air to &longs;tay afloat.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1507"></margin.target>To finde the | |
| <lb/>proportion Fi­ | |
| <lb/>gures ought to | |
| <lb/>have to the wa­ | |
| <lb/>ters Gravity, | |
| <lb/>that by help of | |
| <lb/>the contiguous | |
| <lb/>Air, they may | |
| <lb/>&longs;wim.</s></p><p type="main"> | |
| | |
| <s>Let, therefore, for better illu&longs;tration, D F N E be a Ve&longs;&longs;ell, | |
| <lb/>wherein the water is contained, and &longs;uppo&longs;e a Plate or Board, | |
| <lb/>who&longs;e thickne&longs;s is comprehended between the Lines I C and | |
| <lb/>O S, and let it be of Matter exceeding the water in Gravity, &longs;o that | |
| <lb/>being put upon the water, it dimergeth and aba&longs;eth below the Levell | |
| <lb/>of the &longs;aid water, leaving the little Banks A I and B C, which are at | |
| <lb/>the greate&longs;t height they can be, &longs;o that if the Plate I S &longs;hould but | |
| <lb/>de&longs;cend any little &longs;pace farther, the little Banks or Ramparts would | |
| <lb/>no longer con&longs;i&longs;t, but expul&longs;ing the Air A I C B, they would dif­ | |
| <lb/>fu&longs;e them&longs;elves over the Superficies I C, and | |
| <lb/>would &longs;ubmerge the Plate. </s><s>The height AIBC | |
| <lb/>is therefore the greate&longs;t profundity that the | |
| <lb/><figure id="fig270"></figure> | |
| <lb/>little <emph type="italics"/>B<emph.end type="italics"/>anks of water admit of. </s><s>Now I &longs;ay, | |
| <lb/>that from this, and from the proportion in Gra­ | |
| <lb/>vity, that the Matter of the Plate hath to the | |
| <lb/>water, we may ea&longs;ily &longs;inde of what thickne&longs;s, at mo&longs;t, we may make | |
| <lb/>the &longs;aid Plates, to the end, they may be able to bear up above water: | |
| <lb/>for if the Matter of the Plate or <emph type="italics"/>B<emph.end type="italics"/>oard I S were, for Example, as | |
| <lb/>heavy again as the water, a <emph type="italics"/>B<emph.end type="italics"/>oard of that Matter &longs;hall be, at the mo&longs;t | |
| <lb/>of a thickne&longs;s equall to the greate&longs;t height of the <emph type="italics"/>B<emph.end type="italics"/>anks, that is, as | |
| <lb/>thick as A I is high: which we will thus demon&longs;trate. </s><s>Lot the So­ | |
| <lb/>lid I S be donble in Gravity to the water, and let it be a regular | |
| | |
| | |
| <pb pagenum="446"/>Pri&longs;me, or Cylinder, to wit, that hath its two flat Superficies, &longs;uperi­ | |
| <lb/>our and inferiour, alike and equall, and at Right Angles with the o­ | |
| <lb/>ther laterall Superficies, and let its thickne&longs;s I O be equall to the | |
| <lb/>greate&longs;t Altitude of the Banks of water: I &longs;ay, that if it be put upon | |
| <lb/>the water, it will not &longs;ubmerge: for the Altitude | |
| <lb/>A I being equall to the Altitude I O, the Ma&longs;s | |
| <lb/>of the Air A B C I &longs;hall be equall to the Ma&longs;s of | |
| <lb/><figure id="fig271"></figure> | |
| <lb/>the Solid C I O S: and the whole Ma&longs;s A O S B | |
| <lb/>double to the Ma&longs;s I S; And &longs;ince the Ma&longs;s | |
| <lb/>of the Air A C, neither encrea&longs;eth nor dimi­ | |
| <lb/>ni&longs;heth the Gravity of the Ma&longs;s I S, and the Solid I S was &longs;uppo&longs;ed | |
| <lb/>double in Gravity to the water; Therefore as much water as the | |
| <lb/>Ma&longs;s &longs;ubmerged A O S B, compounded of the Air A I C B, and of | |
| <lb/>the Solid I O S C, weighs ju&longs;t as much as the &longs;ame &longs;ubmerged Ma&longs;s | |
| <lb/>A O S B: but when &longs;uch a Ma&longs;s of water, as is the &longs;ubmerged part of | |
| <lb/>the Solid, weighs as much as the &longs;aid Solid, it de&longs;cends not farther, | |
| <lb/><arrow.to.target n="marg1508"></arrow.to.target> | |
| <lb/>but re&longs;teth, as by <emph type="italics"/>(a) Archimedes,<emph.end type="italics"/> and above by us, hath been de­> | |
| <lb/>mon&longs;trated: Therefore, I S &longs;hall de&longs;cend no farther, but &longs;hall re&longs;t. | |
| <lb/>And if the Solid I S &longs;hall be Se&longs;quialter in Gravity to the water, it | |
| <lb/>&longs;hall float, as long as its thickne&longs;s be not above twice as much as the | |
| <lb/>greate&longs;t Altitude of the Ramparts of water, that is, of A I. </s><s>For I S | |
| <lb/>being Se&longs;quialter in Gravity to the water, and the Altitude O I | |
| <lb/>being double to I A, the Solid &longs;ubmerged A O S B, &longs;hall be al&longs;o | |
| <lb/>Se&longs;quialter in Ma&longs;s to the Solid I S. </s><s>And becau&longs;e the Air A C, | |
| <lb/>neither increa&longs;eth nor dimini&longs;heth the pondero&longs;ity of the Solid I S: | |
| <lb/>Therefore, as much water in quantity as the &longs;ubmerged Ma&longs;s AOSB, | |
| <lb/>weighs as much as the &longs;aid Ma&longs;s &longs;ubmerged: And, therefore, that | |
| <lb/>Ma&longs;s &longs;hall re&longs;t. </s><s>And briefly in generall.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1508"></margin.target>Of Natation | |
| <lb/>Lib. 1. Prop. </s><s>3.</s></p><p type="head"> | |
| | |
| <s>THEOREME. VI.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>When ever the exce&longs;s of the Gravity of the Solid above<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1509"></arrow.to.target> | |
| <lb/><emph type="italics"/>the Gravity of the Water, &longs;hall have the &longs;ame pro­ | |
| <lb/>portion to the Gravity of the Water, that the Alti­ | |
| <lb/>tude of the Rampart, hath to the thickne&longs;s of the | |
| <lb/>Solid, that Solid &longs;hall not &longs;ink, but being never &longs;o lit­ | |
| <lb/>tle thicker it &longs;hall.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1509"></margin.target>The proporti­ | |
| <lb/>on of the great­ | |
| <lb/>e&longs;t thickne&longs;s of | |
| <lb/>Solids, beyond | |
| <lb/>which encrea­ | |
| <lb/>&longs;ed they &longs;ink.</s></p><p type="main"> | |
| | |
| <s>Let the Solid I S be &longs;uperior in Gravity to the water, and of &longs;uch | |
| <lb/>thickne&longs;s, that the Altitude of the Rampart A I, be in proporti­ | |
| <lb/>on to the thickne&longs;s of the Solid I O, as the exce&longs;s of the Gravi­ | |
| <lb/>ty of the &longs;aid Solid I S, above the Gravity of a Ma&longs;s of water equall | |
| <lb/>to the Ma&longs;s I S, is to the Gravity of the Ma&longs;s of water equall to the | |
| | |
| | |
| <pb pagenum="447"/>Ma&longs;s I S. </s><s>I &longs;ay, that the Solid I S &longs;hall not | |
| <lb/>&longs;inke, but being never &longs;o little thicker it &longs;hall | |
| <lb/>go to the bottom: For being that as A I is | |
| <lb/><figure id="fig272"></figure> | |
| <lb/>to I O, &longs;o is the Exce&longs;s of the Gravity of the | |
| <lb/>Solid I S, above the Gravity of a Ma&longs;s of water | |
| <lb/>equall to the Ma&longs;s I S, to the Gravity of the | |
| <lb/>&longs;aid Ma&longs;s of water: Therefore, compounding, as A O is to O I, &longs;o | |
| <lb/>&longs;hall the Gravity of the Solid I S, be to the Gravity of a Ma&longs;s of water | |
| <lb/>equall to the Ma&longs;s I S: And, converting, as I O is to O A, &longs;o &longs;hall the | |
| <lb/>Gravity of a Ma&longs;s of water equall to the Ma&longs;s I S, be to the Gravity | |
| <lb/>of the Solid I S: But as I O is to O A, &longs;o is a Ma&longs;s of water I S, to a | |
| <lb/>Ma&longs;s of water equall to the Ma&longs;s A B S O: and &longs;o is the Gravity of | |
| <lb/>a Ma&longs;s of water I S, to the Gravity of a Ma&longs;s of water A S: Therefore | |
| <lb/>as the Gravity of a Ma&longs;s of water, equall to the Ma&longs;s I S, is to the | |
| <lb/>Gravity of the Solid I S, &longs;o is the &longs;ame Gravity of a Ma&longs;s of water | |
| <lb/>I S, to the Gravity of a Ma&longs;s of Water A S: Therefore the Gra­ | |
| <lb/>vity of the Solid I S, is equall to the Gravity of a Ma&longs;s of water e­ | |
| <lb/>quall to the Ma&longs;s A S: But the Gravity of the Solid I S, is the &longs;ame | |
| <lb/>with the Gravity of the Solid A S, compounded of the Solid I S, | |
| <lb/>and of the Air A B C I. </s><s>Therefore the whole compounded Solid | |
| <lb/>A O S B, weighs as much as the water that would be compri&longs;ed in the | |
| <lb/>place of the &longs;aid Compound A O S B: And, therefore, it &longs;hall make | |
| <lb/>an <emph type="italics"/>Equilibrium<emph.end type="italics"/> and re&longs;t, and that &longs;ame Solid I O S C &longs;hall &longs;inke no | |
| <lb/>farther. </s><s>But if its thickne&longs;s I O &longs;hould be increa&longs;ed, it would be ne­ | |
| <lb/>ce&longs;&longs;ary al&longs;o to encrea&longs;e the Altitude of the Rampart A I, to main­ | |
| <lb/>tain the due proportion: But by what hath been &longs;uppo&longs;ed, the Alti­ | |
| <lb/>tude of the Rampart A I, is the greate&longs;t that the Nature of the | |
| <lb/>Water and Air do admit, without the waters repul&longs;ing the Air ad­ | |
| <lb/>herent to the Superficies of the Solid I C, and po&longs;&longs;e&longs;&longs;ing the &longs;pace | |
| <lb/>A I C B: Therefore, a Solid of greater thickne&longs;s than I O, and of the | |
| <lb/>&longs;ame Matter with the Solid I S, &longs;hall not re&longs;t without &longs;ubmerging, | |
| <lb/>but &longs;hall de&longs;cend to the bottome: which was to be demon&longs;trated. | |
| <lb/></s><s>In con&longs;equence of this that hath been demon&longs;trated, &longs;undry and va­ | |
| <lb/>rious Conclu&longs;ions may be gathered, by which the truth of my prin­ | |
| <lb/>cipall Propo&longs;ition comes to be more and more confirmed, and the | |
| <lb/>imperfection of all former Argumentations touching the pre&longs;ent | |
| <lb/>Que&longs;tion cometh to be di&longs;covered.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>And fir&longs;t we gather from the things demonstrated, that,<emph.end type="italics"/></s></p> | |
| | |
| | |
| <pb pagenum="448"/><p type="head"> | |
| | |
| <s>THEOREME VII. | |
| <lb/><arrow.to.target n="marg1510"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1510"></margin.target>The heavie&longs;t | |
| <lb/>Bodies may | |
| <lb/>&longs;wimme.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>All Matters, how heavy &longs;oever, even to Gold it &longs;elf, the | |
| <lb/>heavie&longs;t of all Bodies, known by us, may float upon | |
| <lb/>the Water.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>Becau&longs;e its Gravity being con&longs;idered to be almo&longs;t twenty times | |
| <lb/>greater than that of the water, and, moreover, the greate&longs;t Alti­ | |
| <lb/>tude that the Rampart of water can be extended to, without break | |
| <lb/>ing the Contiguity of the Air, adherent to the Surface of the Solid, | |
| <lb/>that is put upon the water being predetermined, if we &longs;hould make | |
| <lb/>a Plate of Gold &longs;o thin, that it exceeds not the nineteenth part ofthe | |
| <lb/>Altitude of the &longs;aid Rampart, this put lightly upon the water &longs;hall | |
| <lb/>re&longs;t, without going to the bottom: and if Ebony &longs;hall chance to be | |
| <lb/>in &longs;e&longs;qui&longs;eptimall proportion more grave than the water, the greate&longs;t | |
| <lb/>thickne&longs;s that can be allowed to a Board of Ebony, &longs;o that it may be | |
| <lb/>able to &longs;tay above water without &longs;inking, would be &longs;eaven times | |
| <lb/>more than the height of the Rampart Tinn, <emph type="italics"/>v. </s><s>gr.<emph.end type="italics"/> eight times more | |
| <lb/>grave than water, &longs;hall &longs;wimm as oft as the thickne&longs;s of its Plate,</s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1511"></arrow.to.target> | |
| <lb/>exceeds not the 7th part of the Altitude of the Rampart.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1511"></margin.target><emph type="italics"/>He el&longs;ewhere | |
| <lb/>cites this as a | |
| <lb/>Propo&longs;ition, there­ | |
| <lb/>fore I make it of | |
| <lb/>that number.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>And here I will not omit to note, as a &longs;econd Corrollary dependent | |
| <lb/>upon the things demon&longs;trated, that,</s></p><p type="head"> | |
| | |
| <s>THEOREME VIII. | |
| <lb/><arrow.to.target n="marg1512"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1512"></margin.target>Natation and | |
| <lb/>Submer&longs;ion, col­ | |
| <lb/>lected from the | |
| <lb/>thickne&longs;s, exclu­ | |
| <lb/>ding the length | |
| <lb/>and breadth of | |
| <lb/>Plates.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>The Expan&longs;ion of Figure not only is not the Cau&longs;e of the | |
| <lb/>Natation of tho&longs;e grave Bodies, which otherwi&longs;e | |
| <lb/>do &longs;ubmerge, but al&longs;o the determining what be tho&longs;e | |
| <lb/>Boards of Ebony, or Plates of Iron or Gold that will | |
| <lb/>&longs;wimme, depends not on it, rather that &longs;ame determina­ | |
| <lb/>tion is to be collected from the only thickne&longs;s of tho&longs;e | |
| <lb/>Figures of Ebony or Gold, wholly excluding the con­ | |
| <lb/>&longs;ideration of length and breadth, as having no way | |
| <lb/>any &longs;hare in this Effect.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>It hath already been manife&longs;ted, that the only cau&longs;e of the Nata­ | |
| <lb/>tion of the &longs;aid Plates, is the reduction of them to be le&longs;s grave | |
| <lb/>than the water, by means of the connexion of that Air, which de­ | |
| <lb/>&longs;cendeth together with them, and po&longs;&longs;e&longs;&longs;eth place in the water; | |
| <lb/>which place &longs;o occupyed, if before the circumfu&longs;ed water diffu&longs;eth | |
| <lb/>it &longs;elf to fill it, it be capable of as much water, as &longs;hall weigh equall | |
| <lb/>with the Plate, the Plate &longs;hall remain &longs;u&longs;pended, and &longs;inke no | |
| <lb/>farther.</s></p> | |
| | |
| | |
| <pb pagenum="449"/><p type="main"> | |
| | |
| <s>Now let us &longs;ee on which of the&longs;e three dimen&longs;ions of the Solid | |
| <lb/>depends the terminating, what and how much the Ma&longs;s of that ought | |
| <lb/>to be, that &longs;o the a&longs;&longs;i&longs;tance of the Air contiguous unto it, may &longs;uffice | |
| <lb/>to render it &longs;pecifically le&longs;s grave than the water, whereupon it may | |
| <lb/>re&longs;t without Submer&longs;ion. </s><s>It &longs;hall undoubtedly be found, that the | |
| <lb/>length and breadth have not any thing to do in the &longs;aid determina­ | |
| <lb/>tion, but only the height, or if you will the thickne&longs;s: for, if we take | |
| <lb/>a Plate or Board, as for Example, of Ebony, who&longs;e Altitude hath | |
| <lb/>unto the greate&longs;t po&longs;&longs;ible Altitude of the Rampart, the proportion | |
| <lb/>above declared, for which cau&longs;e it &longs;wims indeed, but yet not if we | |
| <lb/>never &longs;o little increa&longs;e its thickne&longs;s; I &longs;ay, that retaining its thick­ | |
| <lb/>ne&longs;s, and encrea&longs;ing its Superficies to twice, four times, or ten times | |
| <lb/>its bigne&longs;s, or dmini&longs;ning it by dividing it into four, or &longs;ix, or | |
| <lb/>twenty, or a hundred parts, it &longs;hall &longs;till in the &longs;ame manner continue | |
| <lb/>to float: but encrea&longs;ing its thickne&longs;s only a Hairs breadth, it will | |
| <lb/>alwaies &longs;ubmerge, although we &longs;hould multiply the Superficies a | |
| <lb/>hundred and a hundred times. </s><s>Now fora&longs;much as that this is a | |
| <lb/>Cau&longs;e, which being added, we adde al&longs;o the Effect, and being remo­ | |
| <lb/>ved, it is removed; and by augmenting or le&longs;&longs;ening the length or | |
| <lb/>breadth in any manner, the effect of going, or not going to the bot­ | |
| <lb/>tom, is not added or removed: I conclude, that the greatne&longs;s and | |
| <lb/>&longs;malne&longs;s of the Superficies hath no influence upon the Natation or | |
| <lb/>Submer&longs;ion. </s><s>And that the proportion of the Altitude of the Ram­ | |
| <lb/>parts of Water, to the Altitude of the Solid, being con&longs;tituted in | |
| <lb/>the manner afore&longs;aid, the greatne&longs;s or &longs;malne&longs;s of the Superficies, | |
| <lb/>makes not any variation, is manife&longs;t from that which hath been above | |
| <lb/>demon&longs;trated, and from this, that, <emph type="italics"/>The Pri&longs;ms and Cylinders which<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1513"></arrow.to.target> | |
| <lb/><emph type="italics"/>have the &longs;ame Ba&longs;e, are in proportion to one another as their heights:<emph.end type="italics"/> | |
| <lb/>Whence Cylinders or Prifmes, namely, the Board, be they great or | |
| <lb/>little, &longs;o that they be all of equall thickne&longs;s, have the &longs;ame proportion | |
| <lb/>to their Conterminall Air, which hath for Ba&longs;e the &longs;aid Superficies of | |
| <lb/>the Board, and for height the Ramparts of water; &longs;o that alwayes | |
| <lb/>of that Air, and of the Board, Solids are compounded, that in Gravity | |
| <lb/>equall a Ma&longs;s of water equall to the Ma&longs;s of the Solids, compounded | |
| <lb/>of Air, and of the Board: whereupon all the &longs;aid Solids do in the | |
| <lb/>&longs;ame manner continue afloat. </s><s>We will conclude in the third place, | |
| <lb/>that,</s></p> | |
| | |
| | |
| <pb pagenum="450"/><p type="margin"> | |
| | |
| <s><margin.target id="marg1513"></margin.target>Pri&longs;mes and | |
| <lb/>Cylinders ha­ | |
| <lb/>ving the &longs;ame | |
| <lb/>Ba&longs;e, are to one | |
| <lb/>another as their | |
| <lb/>heights.</s></p><p type="head"> | |
| | |
| <s>THEOREME. IX. | |
| <lb/><arrow.to.target n="marg1514"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1514"></margin.target>All Figures | |
| <lb/>of all Matters, | |
| <lb/>float by hep of | |
| <lb/>the Rampart re­ | |
| <lb/>pleni&longs;hed with | |
| <lb/>Air, and &longs;ome | |
| <lb/>but only touch | |
| <lb/>the water.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>All &longs;orts of Figures of what&longs;oever Matter, albeit more | |
| <lb/>grave than the Water, do by Benefit of the &longs;aid Ram­ | |
| <lb/>part, not only float, but &longs;ome Figures, though of the | |
| <lb/>grave&longs;t Matter, do &longs;tay wholly above Water, wetting | |
| <lb/>only the inferiour Surface that toucheth the Water.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>And the&longs;e &longs;hall be all Figures, which from the inferiour Ba&longs;e up­ | |
| <lb/>wards, grow le&longs;&longs;er and le&longs;&longs;er; the which we &longs;hall exemplifie for | |
| <lb/>this time in Piramides or Cones, of which Figures the pa&longs;&longs;ions sre | |
| <lb/>common. </s><s>We will demon&longs;trate therefore, that,</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>It is po&longs;&longs;ible to form a Piramide, of any what&longs;oever Matter propo&longs;ed, | |
| <lb/>which being put with its Ba&longs;e upon the Water, re&longs;ts not only without | |
| <lb/>&longs;ubmerging, but without wetting it more then its Ba&longs;e.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>For the explication of which it is requi&longs;ite, that we fir&longs;t demon&longs;trate | |
| <lb/>the &longs;ub&longs;equent Lemma, namely, that,</s></p><p type="head"> | |
| | |
| <s>LEMMA II.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Solids who&longs;e Ma&longs;&longs;es an&longs;wer in proportion contrarily to<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1515"></arrow.to.target> | |
| <lb/><emph type="italics"/>their Specificall Gravities, are equall in Ab&longs;olute | |
| <lb/>Gravities.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1515"></margin.target>Solids who&longs;e | |
| <lb/>Ma&longs;&longs;es are in | |
| <lb/>contrary pro­ | |
| <lb/>portion to their | |
| <lb/>Specifick Gra­ | |
| <lb/>vities, are equall | |
| <lb/>in ab&longs;olute Gra | |
| <lb/>vity.</s></p><p type="main"> | |
| | |
| <s>Let A C and B be two Solids, and let the Ma&longs;s A C be to the | |
| <lb/>Ma&longs;s B, as the Specificall Gravity of the Solid B, is to the Speci­ | |
| <lb/>ficall Gravity of the Solid A C: I &longs;ay, the Solids A C and B are | |
| <lb/>equall in ab&longs;olute weight, that is, equally grave. For | |
| <lb/><figure id="fig273"></figure> | |
| <lb/>if the Ma&longs;s A C be equall to the Ma&longs;s B, then, by the | |
| <lb/>A&longs;&longs;umption, the Specificall Gravity of B, &longs;hall be e­ | |
| <lb/>quall to the Specificall Gravity of A C, and being e­ | |
| <lb/>quall in Ma&longs;s, and of the &longs;ame Specificall Gravity they | |
| <lb/>&longs;hall ab&longs;olutely weigh one as much as another. </s><s>But | |
| <lb/>if their Ma&longs;&longs;es &longs;hall be unequall, let the Ma&longs;s A C be greater, and in it | |
| <lb/>take the part C, equall to the Ma&longs;s B. And, becau&longs;e the Ma&longs;&longs;es B | |
| <lb/>and C are equall; the Ab&longs;olute weight of B, &longs;hall have the &longs;ame pro­ | |
| <lb/>portion to the Ab&longs;olute weight of C, that the Specificall Gravity of | |
| <lb/>B, hath to the Specificall Gravity of C; or of C A, which is the | |
| <lb/>&longs;ame <emph type="italics"/>in &longs;pecie<emph.end type="italics"/>: But look what proportion the Specificall Gravity of | |
| <lb/>B, hath to the Specificall Gravity of C A, the like proportion, by the | |
| <lb/>A&longs;&longs;umption, hath the Ma&longs;s C A, to the Ma&longs;s B; that is, to the Ma&longs;s C: | |
| | |
| | |
| <pb pagenum="451"/>Therefore, the ab&longs;olute weight of B, to the ab&longs;olute weight of C, is | |
| <lb/>as the Ma&longs;s A C to the Ma&longs;s <emph type="italics"/>C<emph.end type="italics"/>: But as the Ma&longs;s AC, is to the Ma&longs;s C, | |
| <lb/>&longs;o is the ab&longs;olute weight of A C, to the ab&longs;olute weight of C: There­ | |
| <lb/>fore the ab&longs;olute weight of B, hath the &longs;ame proportion to the ab&longs;o­ | |
| <lb/>lute weight of C, that the ab&longs;olute weight of A C, hath to the ab­ | |
| <lb/>&longs;olute weight of C: Therefore, the two Solids A C and B are equall | |
| <lb/>in ab&longs;olute Gravity: which was to be demon&longs;trated. </s><s>Having de­ | |
| <lb/>mon&longs;trated this, I &longs;ay,</s></p><p type="head"> | |
| | |
| <s>THEOREME X.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>That it is po&longs;&longs;ible of any a&longs;&longs;igned Matter, to form a Pi-<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1516"></arrow.to.target> | |
| <lb/><emph type="italics"/>ramide or Cone upon any Ba&longs;e, which being put upon | |
| <lb/>the Water &longs;hall not &longs;ubmerge, nor wet any more than | |
| <lb/>its Ba&longs;e.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1516"></margin.target>There may be | |
| <lb/>Cones and Pira­ | |
| <lb/>mides of any | |
| <lb/><emph type="italics"/>M<emph.end type="italics"/>atter, which | |
| <lb/>demittedinto the | |
| <lb/>water, re&longs;t only | |
| <lb/>their Ba&longs;es.</s></p><p type="main"> | |
| | |
| <s>Let the greate&longs;t po&longs;&longs;ible Altitude of the Rampart be the Line D B, | |
| <lb/>and the Diameter of the Ba&longs;e of the Cone to be made of any Mat­ | |
| <lb/>ter a&longs;&longs;igned B C, at right angles to D B: And as the Specificall Gravity | |
| <lb/>of the Matter of the Piramide or Cone to be made, is to the Specificall | |
| <lb/>Gravity of the water, &longs;o let the Altitude of the | |
| <lb/><figure id="fig274"></figure> | |
| <lb/>Rampart D B, be to the third part of the Piramide | |
| <lb/>or Cone A B C, de&longs;cribed upon the Ba&longs;e, who&longs;e | |
| <lb/>Diameter is B C: I &longs;ay, that the &longs;aid Cone A B C, | |
| <lb/>and any other Cone, lower then the &longs;ame, &longs;hall re&longs;t | |
| <lb/>upon the Surface of the water B C without &longs;inking. | |
| <lb/></s><s>Draw D F parallel to B C, and &longs;uppo&longs;e the Pri&longs;me | |
| <lb/>or Cylinder E C, which &longs;hall be tripple to the Cone | |
| <lb/>A B C. And, becau&longs;e the Cylinder D C hath the &longs;ame proportion | |
| <lb/>to the Cylinder C E, that the Altitude D B, hath to the Altitude B E: | |
| <lb/>But the Cylinder C E, is to the Cone A B C, as the Altitude E B is to | |
| <lb/>the third part of the Altitude of the Cone: Therefore, by Equality of | |
| <lb/>proportion, the Cylinder D C is to the Cone A B C, as D B is to the | |
| <lb/>third part of the Altitude B E: But as D B is to the third part of B E, | |
| <lb/>&longs;o is the Specificall Gravity of the Cone A B C, to the Specificall Gra­ | |
| <lb/>vity of the water: Therefore, as the Ma&longs;s of the Solid D C, is to the | |
| <lb/>Ma&longs;s of the Cone A <emph type="italics"/>B<emph.end type="italics"/> C, &longs;o is the Specificall Gravity of the &longs;aid Cone, | |
| <lb/>to the Specificall Gravity of the water: Therefore, by the precedent | |
| <lb/>Lemma, the Cone A B C weighs in ab&longs;olute Gravity as much as a | |
| <lb/>Ma&longs;s of Water equall to the Ma&longs;s D C: But the water which by the | |
| <lb/>impo&longs;ition of the Cone A B C, is driven out of its place, is as much | |
| <lb/>as would preci&longs;ely lie in the place D C, and is equall in weight to the | |
| <lb/>Cone that di&longs;placeth it: Therefore, there &longs;hall be an <emph type="italics"/>Equilibrium,<emph.end type="italics"/> | |
| <lb/>and the Cone &longs;hall re&longs;t without farther &longs;ubmerging. </s><s>And its ma­ | |
| <lb/>nife&longs;t,</s></p> | |
| | |
| | |
| <pb pagenum="452"/><p type="head"> | |
| | |
| <s>COROLARY I. | |
| <lb/><arrow.to.target n="marg1517"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1517"></margin.target>Among&longs;t Cones | |
| <lb/>of the &longs;ame Ba&longs;e, | |
| <lb/>tho&longs;e of lea&longs;t Al­ | |
| <lb/>titude &longs;hall &longs;ink | |
| <lb/>the lea&longs;t.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>That making upon the &longs;ame Ba&longs;is, a Cone of a le&longs;s Altitude, it &longs;hall be | |
| <lb/>al&longs;o le&longs;s grave, and &longs;hall &longs;o much the more re&longs;t without Submer&longs;ion.<emph.end type="italics"/></s></p><p type="head"> | |
| | |
| <s>COROLARY II.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>It is manife&longs;t, al&longs;o, that one may make Cones and Piramids of any Matter <emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1518"></arrow.to.target> | |
| <lb/><emph type="italics"/>what&longs;oever, more grave than the water, which being put into the | |
| <lb/>water, with the Apix or Point downwards, re&longs;t without Submer&longs;ion. <emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1518"></margin.target>There may be | |
| <lb/>Cones and Pira­ | |
| <lb/>mides of any | |
| <lb/>Matter, which | |
| <lb/>demitted with | |
| <lb/>the Point down­ | |
| <lb/>wards do float a­ | |
| <lb/>top.</s></p><p type="main"> | |
| | |
| <s>Becau&longs;e if we rea&longs;&longs;ume what hath been above demon&longs;trated, of | |
| <lb/>Pri&longs;ms and Cylinders, and that on Ba&longs;es equall to tho&longs;e of the | |
| <lb/>&longs;aid Cylinders, we make Cones of the &longs;ame Matter, and thrree | |
| <lb/>times as high as the Cylinders, they &longs;hall re&longs;t afloat, for that in Ma&longs;s | |
| <lb/>and Gravity they &longs;hall be equall to tho&longs;e Cylinders, and by having | |
| <lb/>their Ba&longs;es equall to tho&longs;e of the Cylinders, they &longs;hall leave equall | |
| <lb/>Ma&longs;&longs;es of Air included within the Ramparts. </s><s>This, which for Exam­ | |
| <lb/>ple &longs;ake hath been demon&longs;trated, in Pri&longs;ms, Cylinders, Cones and | |
| <lb/>Piramids, might be proved in all other Solid Figures, but it would | |
| <lb/>require a whole Volume (&longs;uch is the multitude and variety of their | |
| <lb/>Symptoms and Accidents) to comprehend the particuler demon&longs;tration | |
| <lb/>of them all, and of their &longs;everall Segments: but I will to avoid prolixity | |
| <lb/>in the pre&longs;ent Di&longs;cour&longs;e, content my &longs;elf, that by what I have declared | |
| <lb/>every one of ordinary Capacity may comprehend, that there is not | |
| <lb/>any Matter &longs;o grave, no not Gold it &longs;elf, of which one may not form | |
| <lb/>all &longs;orts of Figures, which by vertue of the &longs;uperiour Air adherent to | |
| <lb/>them, and not by the Waters Re&longs;i&longs;tance of Penetration, do remain | |
| <lb/>afloat, &longs;o that they &longs;ink not. </s><s>Nay, farther, I will &longs;hew, for removing | |
| <lb/>that Error, that,</s></p><p type="head"> | |
| | |
| <s>THEOREME XI. | |
| <lb/><arrow.to.target n="marg1519"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1519"></margin.target>A Piramide or | |
| <lb/>Cone, demitted | |
| <lb/>with the Point | |
| <lb/>downwards &longs;hal | |
| <lb/>&longs;wim, with its | |
| <lb/>Ba&longs;e downward | |
| <lb/>&longs;hall &longs;ink.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>A Piramide or Cone put into the Water, with the Point | |
| <lb/>downward &longs;hall &longs;wimme, and the &longs;ame put with the | |
| <lb/>Ba&longs;e downwards &longs;hall &longs;inke, and it &longs;hall be impo&longs;&longs;ible | |
| <lb/>to make it float.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>Now the quite contrary would happen, if the difficulty of Pene­ | |
| <lb/>trating the water, were that which had hindred the de&longs;cent, for | |
| <lb/>that the &longs;aid Cone is far apter to pierce and penetrate with its &longs;harp | |
| <lb/>Point, than with its broad and &longs;pacious Ba&longs;e.</s></p><p type="main"> | |
| | |
| <s>And, to demon&longs;trate this, let the Cone be <emph type="italics"/>A B C,<emph.end type="italics"/> twice as grave | |
| <lb/>as the water, and let its height be tripple to the height of the Rampart | |
| <lb/><emph type="italics"/>D A E C<emph.end type="italics"/>: I &longs;ay, fir&longs;t, that being put lightly into the water with the | |
| | |
| | |
| <pb pagenum="453"/>Point downwards, it &longs;hall not de&longs;cend to the bot­ | |
| <lb/>tom: for the Aeriall Cylinder contained betwixt | |
| <lb/><figure id="fig275"></figure> | |
| <lb/>the Ramparts <emph type="italics"/>D A C E,<emph.end type="italics"/> is equall in Ma&longs;s to the | |
| <lb/>Cone <emph type="italics"/>A B C<emph.end type="italics"/>; &longs;o that the whole Ma&longs;s of the Solid | |
| <lb/>compounded of the Air <emph type="italics"/>D A C E,<emph.end type="italics"/> and of the Cone | |
| <lb/><emph type="italics"/>A B C,<emph.end type="italics"/> &longs;hall be double to the Cone <emph type="italics"/>A C B:<emph.end type="italics"/> And, | |
| <lb/>becau&longs;e the Cone <emph type="italics"/>A B C<emph.end type="italics"/> is &longs;uppo&longs;ed to be of Matter double in Gra­ | |
| <lb/>vity to the water, therefore as much water as the whole Ma&longs;&longs;e | |
| <lb/><emph type="italics"/>D A B C E,<emph.end type="italics"/> placed beneath the Levell of the water, weighs as much | |
| <lb/>as the Cone <emph type="italics"/>A B C<emph.end type="italics"/>: and, therefore, there &longs;hall be an <emph type="italics"/>Equilibrium,<emph.end type="italics"/> | |
| <lb/>and the Cone <emph type="italics"/>A B C<emph.end type="italics"/> &longs;hall de&longs;cend no lower. </s><s>Now, I &longs;ay farther, | |
| <lb/>that the &longs;ame Cone placed with the Ba&longs;e downwards, &longs;hall &longs;ink to | |
| <lb/>the bottom, without any po&longs;&longs;ibility of returning again, by any means | |
| <lb/>to &longs;wimme.</s></p><p type="main"> | |
| | |
| <s>Let, therefore, the Cone be <emph type="italics"/>A B D,<emph.end type="italics"/> double in Gravity to the | |
| <lb/>water, and let its height be tripple the height | |
| <lb/><figure id="fig276"></figure> | |
| <lb/>of the Rampart of water L B: It is already | |
| <lb/>manife&longs;t, that it &longs;hall not &longs;tay wholly out of | |
| <lb/>the water, becau&longs;e the Cylinder being com­ | |
| <lb/>prehended betwixt the Ramparts <emph type="italics"/>L B D P,<emph.end type="italics"/> | |
| <lb/>equall to the Cone <emph type="italics"/>A B D,<emph.end type="italics"/> and the Matter of | |
| <lb/>the Cone, beig double in Gravity to the | |
| <lb/>water, it is evident that the weight of the &longs;aid | |
| <lb/>Cone &longs;hall be double to the weight of the Ma&longs;s of water equall to the | |
| <lb/>Cylinder <emph type="italics"/>L B D P<emph.end type="italics"/>: Therefore it &longs;hall not re&longs;t in this &longs;tate, but | |
| <lb/>&longs;hall de&longs;cend.</s></p><p type="head"> | |
| | |
| <s>COROLARY I.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>I &longs;ay farther; that much le&longs;&longs;e &longs;hall the &longs;aid Cone stay afloat, if one<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1520"></arrow.to.target> | |
| <lb/><emph type="italics"/>immerge a part thereof.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1520"></margin.target>Much le&longs;s &longs;hall | |
| <lb/>the &longs;aid Cone | |
| <lb/>&longs;wim, if one im­ | |
| <lb/>merge a part | |
| <lb/>thereof.</s></p><p type="main"> | |
| | |
| <s>Which you may &longs;ee, comparing with the water as well the part | |
| <lb/>that &longs;hall immerge as the other above water. </s><s>Let us therefore | |
| <lb/>of the Cone A B D, &longs;ubmergeth part N T O S, and advance the | |
| <lb/>Point N S F above water. </s><s>The Altitude of the Cone F N S, &longs;hall | |
| <lb/>either be more than half the whole Altitude of the Cone F T O, or | |
| <lb/>it &longs;hall not be more: if it &longs;hall be more than half, the Cone F N S | |
| <lb/>&longs;hall be more than half of the Cylinder E N S C: for the Altitude | |
| <lb/>of the Cone F N S, &longs;hall be more than Se&longs;quialter of the Altitude | |
| <lb/>of the Cylinder E N S C: And, becau&longs;e the Matter of the Cone is | |
| <lb/>&longs;uppo&longs;ed to be double in Specificall Gravity to the water, the water | |
| <lb/>which would be contained within the Rampart E N S C, would be | |
| <lb/>le&longs;s grave ab&longs;olutely than the Cone F N S; &longs;o that the whole Cone | |
| <lb/>F N S cannot be &longs;u&longs;tained by the Rampart: But the part immerged | |
| <lb/>N T O S, by being double in Specificall Gravity to the water, &longs;hall | |
| | |
| | |
| <pb pagenum="454"/>tend to the bottom: Therefore, the whole <emph type="italics"/>C<emph.end type="italics"/>one F T O, as well in | |
| <lb/>re&longs;pect of the part &longs;ubmerged, as the part above water &longs;hall de­ | |
| <lb/>&longs;cend to the bottom. </s><s>But if the Altitude of the Point F N S, &longs;hall | |
| <lb/>be half the Altitude of the whole Cone F T O, the &longs;ame Altitude of | |
| <lb/>the &longs;aid <emph type="italics"/>C<emph.end type="italics"/>one F N S &longs;hall be Se&longs;quialter to the Altitude E N: and, | |
| <lb/>therefore, E N S C &longs;hall be double to the Cone F N S; and as much | |
| <lb/>water in Ma&longs;s as the <emph type="italics"/>C<emph.end type="italics"/>ylinder E N S C, would weigh as much as the | |
| <lb/>part of the <emph type="italics"/>C<emph.end type="italics"/>one F N S. But, becau&longs;e the other immerged part | |
| <lb/>N T O S, is double in Gravity to the water, a Ma&longs;s of water equall | |
| <lb/>to that compounded of the <emph type="italics"/>C<emph.end type="italics"/>ylinder E N S C, and of the Solid N T O S, | |
| <lb/>&longs;hall weigh le&longs;s than the <emph type="italics"/>C<emph.end type="italics"/>one F T O, by as much as the weight of | |
| <lb/>a Ma&longs;s of water equall to the Solid N T O S: Therefore, the <emph type="italics"/>C<emph.end type="italics"/>one | |
| <lb/>&longs;ha l al&longs;o de&longs;cend. </s><s>Again, becau&longs;e the Solid N T O S, is &longs;eptuple | |
| <lb/>to the <emph type="italics"/>C<emph.end type="italics"/>one F N S, to which the <emph type="italics"/>C<emph.end type="italics"/>ylinder E S is double, the propor­ | |
| <lb/>tion of the Solid N T O S, &longs;hall be to the <emph type="italics"/>C<emph.end type="italics"/>ylinder E N S C, as &longs;eaven | |
| <lb/>to two: Therefore, the whole Solid compounded of the <emph type="italics"/>C<emph.end type="italics"/>ylinder | |
| <lb/>E N S C, and of the Solid N T O S, is much le&longs;s than double the | |
| <lb/>Solid N T O S: Therefore, the &longs;ingle Solid N T O S, is much graver | |
| <lb/>than a Ma&longs;s of water equall to the Ma&longs;s, compounded of the <emph type="italics"/>C<emph.end type="italics"/>y­ | |
| <lb/>linder E N S C, and of N T O S.</s></p><p type="head"> | |
| | |
| <s>COROLARY II. | |
| <lb/><arrow.to.target n="marg1521"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1521"></margin.target>Part of the | |
| <lb/>Cones towards | |
| <lb/>the Cu&longs;pis remo­ | |
| <lb/>ved, it &longs;hall &longs;till | |
| <lb/>&longs;ink.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>From whence it followeth, that though one &longs;hould remove and take a­ | |
| <lb/>way the part of the Cone F N S, the &longs;ole remainder N T O S would | |
| <lb/>go to the bottom.<emph.end type="italics"/></s></p><p type="head"> | |
| | |
| <s>COROLARY III.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>And if we &longs;hould more depre&longs;s the Cone F T O, it would be &longs;o much the<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1522"></arrow.to.target> | |
| <lb/><emph type="italics"/>more impo&longs;&longs;ible that it &longs;hould &longs;u&longs;tain it &longs;elf afloat, the part &longs;ubmerged | |
| <lb/>N T O S &longs;till encrea&longs;ing, and the Ma&longs;s of Air contained in the Rampart | |
| <lb/>dimini&longs;hing, which ever grows le&longs;s, the more the Cone &longs;ubmergeth.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1522"></margin.target>The more the | |
| <lb/>Cone is immer­ | |
| <lb/>ged, the more | |
| <lb/>impo&longs;&longs;ible is its | |
| <lb/>floating.</s></p><p type="main"> | |
| | |
| <s>That Cone, therefore, that with its Ba&longs;e upwards, and its | |
| <lb/><emph type="italics"/>Cu&longs;pis<emph.end type="italics"/> downwards doth &longs;wimme, being dimitted with its Ba&longs;e | |
| <lb/>downward mu&longs;t of nece&longs;&longs;ity &longs;inke. </s><s>They have argued farre | |
| <lb/>from the truth, therefore, who have a&longs;cribed the cau&longs;e of Natation | |
| <lb/>to waters re&longs;i&longs;tance of Divi&longs;ion, as to a pa&longs;&longs;ive principle, and to the | |
| <lb/>breadth of the Figure, with which the divi&longs;ion is to be made, as the | |
| <lb/>Efficient.</s></p><p type="main"> | |
| | |
| <s>I come in the fourth place, to collect and conclude the rea&longs;on of | |
| <lb/>that which I have propo&longs;ed to the Adver&longs;aries, namely,</s></p> | |
| | |
| | |
| <pb pagenum="455"/><p type="head"> | |
| | |
| <s>THE OREME XII.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>That it is po&longs;&longs;ible to fo m Solid Bodies, of what Figure<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1523"></arrow.to.target> | |
| <lb/><emph type="italics"/>and greatne&longs;s &longs;oever, that of their own Nature goe | |
| <lb/>to the Bottome; But by the help of the Air con­ | |
| <lb/>tained in the Rampart, re&longs;t without &longs;ubmerging.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1523"></margin.target>Solids of any | |
| <lb/>Figure & great­ | |
| <lb/>ne&longs;&longs;e, that natu­ | |
| <lb/>rally &longs;ink, may | |
| <lb/>by help of the | |
| <lb/>Air in the Ram­ | |
| <lb/>part &longs;wimme.</s></p><p type="main"> | |
| | |
| <s>The truth of this Propo&longs;ition is &longs;ufficiently manife&longs;t in all tho&longs;e | |
| <lb/>Solid Figures, that determine in their uppermo&longs;t part in a plane | |
| <lb/>Superficies: for making &longs;uch Figures of &longs;ome Matter &longs;pecifi­ | |
| <lb/>cally as grave as the water, putting them into the water, &longs;o that the | |
| <lb/>whole Ma&longs;s be covered, it is manife&longs;t, that they &longs;hall re&longs;t in all | |
| <lb/>places, provided, that &longs;uch a Matter equall in weight to the water, | |
| <lb/>may be exactly adju&longs;ted: and they &longs;hall by con&longs;equence, re&longs;t or | |
| <lb/>lie even with the Levell of the water, without making any Rampart. | |
| <lb/></s><s>If, therefore, in re&longs;pect of the Matter, &longs;uch Figures are apt to re&longs;t | |
| <lb/>without &longs;ubmerging, though deprived of the help of the Rampart, | |
| <lb/>it is manife&longs;t, that they may admit &longs;o much encrea&longs;e of Gravity, | |
| <lb/>(without encrea&longs;ing their Ma&longs;&longs;es) as is the weight of as much water | |
| <lb/>as would be contained within the Rampart, that is made about their | |
| <lb/>upper plane Surface: by the help of which being &longs;u&longs;tained, they | |
| <lb/>&longs;hall re&longs;t afloat, but being bathed, they &longs;hall de&longs;cend, having been | |
| <lb/>made graver than the water. </s><s>In Figures, therefore, that determine | |
| <lb/>above in a plane, we may cleerly comprehend, that the Rampart | |
| <lb/>added or removed, may prohibit or permit the de&longs;cent: but in tho&longs;e | |
| <lb/>Figures that go le&longs;&longs;ening upwards towards the top, &longs;ome Per&longs;ons | |
| <lb/>may, and that not without much &longs;eeming Rea&longs;on, doubt whether | |
| <lb/>the &longs;ame may be done, and e&longs;pecially by tho&longs;e which terminate in a | |
| <lb/>very acute Point, &longs;uch as are your Cones and &longs;mall Piramids. </s><s>Touch­ | |
| <lb/>ing the&longs;e, therefore, as more dubious than the re&longs;t, I will endeavour | |
| <lb/>to demon&longs;trate, that they al&longs;o lie under the &longs;ame Accident of going, | |
| <lb/>or not going to the Bottom, be they of any whatever bigne&longs;s. </s><s>Let | |
| <lb/>therefore the Cone be A B D, made of a matter | |
| <lb/>&longs;pecifically as grave as the water; it is manife&longs;t | |
| <lb/><figure id="fig277"></figure> | |
| <lb/>that being put all under water, it &longs;hall re&longs;t in | |
| <lb/>all places (alwayes provided, that it &longs;hall weigh | |
| <lb/>exactly as much as the water, which is almo&longs;t | |
| <lb/>impo&longs;&longs;ible to effect) and that any &longs;mall weight | |
| <lb/>being added to it, it &longs;hall &longs;ink to the bottom: | |
| <lb/>but if it &longs;hall de&longs;cend downwards gently, I &longs;ay, | |
| <lb/>that it &longs;hall make the Rampart E S T O, and | |
| <lb/>that there &longs;hall &longs;tay out of the water the point A S T, tripple in | |
| <lb/>height to the Rampart E S: which is manife&longs;t, for the Matter of the | |
| | |
| | |
| <pb pagenum="456"/>Cone weighing equally with the water, the part &longs;ubmerged S B D T, | |
| <lb/>becomes indifferent to move downwards or upwards; and the Cone | |
| <lb/><emph type="italics"/>A S T,<emph.end type="italics"/> being equall in Ma&longs;s to the water that would be contained in | |
| <lb/>the concave of the Rampart <emph type="italics"/>E S T O,<emph.end type="italics"/> &longs;hall be al&longs;o equall unto it in | |
| <lb/>Gravity: and, therefore, there &longs;hall be a perfect <emph type="italics"/>Equilibrium,<emph.end type="italics"/> and, | |
| <lb/>con&longs;equently, a Re&longs;t. </s><s>Now here ari&longs;eth a doubt, whether the | |
| <lb/>Cone <emph type="italics"/>A B D<emph.end type="italics"/> may be made heavier, in &longs;uch &longs;ort, that when it is put | |
| <lb/>wholly under water, it goes to the bottom, but yet not in &longs;uch &longs;ort, | |
| <lb/>as to take from the Rampart the vertue of &longs;u&longs;taining it that it &longs;ink not, | |
| <lb/>and, the rea&longs;on of the doubt is this: that although at &longs;uch time as | |
| <lb/>the Cone <emph type="italics"/>A B D<emph.end type="italics"/> is &longs;pecifically as grave as the water, the Rampart | |
| <lb/><emph type="italics"/>E S T O<emph.end type="italics"/> &longs;u&longs;taines it, not only when the point <emph type="italics"/>A S T<emph.end type="italics"/> is tripple in | |
| <lb/>height to the Altitude of the Rampart <emph type="italics"/>E S,<emph.end type="italics"/> but al&longs;o when a le&longs;&longs;er | |
| <lb/>part is above water; [for although in the De&longs;cent of the Cone the | |
| <lb/>Point <emph type="italics"/>A S T<emph.end type="italics"/> by little and little dimini&longs;heth, and &longs;o likewi&longs;e the | |
| <lb/>Rampart <emph type="italics"/>E S T O,<emph.end type="italics"/> yet the Point dimini&longs;heth in | |
| <lb/><figure id="fig278"></figure> | |
| <lb/>greater proportion than the Rampart, in that | |
| <lb/>it dimini&longs;heth according to all the three Di­ | |
| <lb/>men&longs;ions, but the Rampart according to two | |
| <lb/>only, the Altitude &longs;till remaining the &longs;ame; | |
| <lb/>or, if you will, becau&longs;e the Cone <emph type="italics"/>S T<emph.end type="italics"/> goes di­ | |
| <lb/>mini&longs;hing, according to the proportion of the | |
| <lb/>cubes of the Lines that do &longs;ucce&longs;&longs;ively become | |
| <lb/>the Diameters of the Ba&longs;es of emergent Cones, | |
| <lb/>and the Ramparts dimini&longs;h according to the proportion of the | |
| <lb/>Squares of the &longs;ame Lines; whereupon the proportions of the Points | |
| <lb/>are alwayes Se&longs;quialter of the proportions of the Cylinders, con­ | |
| <lb/>tained within the Rampart; &longs;o that if, for Example, the height of | |
| <lb/>the emergent Point were double, or equall to the height of the | |
| <lb/>Rampart, in the&longs;e ca&longs;es, the Cylinder contained within the Ram­ | |
| <lb/>part, would be much greater than the &longs;aid Point, becau&longs;e it would be | |
| <lb/>either &longs;e&longs;quialter or tripple, by rea&longs;on of which it would perhaps | |
| <lb/>&longs;erve over and above to fu&longs;tain the whole Cone, &longs;ince the part &longs;ub­ | |
| <lb/>merged would no longer weigh any thing;] yet, neverthele&longs;s, when | |
| <lb/>any Gravity is added to the whole Ma&longs;s of the Cone, &longs;o that al&longs;o the | |
| <lb/>part &longs;ubmerged is not without &longs;ome exce&longs;&longs;e of Gravity above the | |
| <lb/>Gravity of the water, it is not manife&longs;t, whether the Cylinder con­ | |
| <lb/>tained within the Rampart, in the de&longs;cent that the Cone &longs;hall make, | |
| <lb/>can be reduced to &longs;uch a proportion unto the emergent Point, and to | |
| <lb/>&longs;uch an exce&longs;&longs;e of Ma&longs;s above the Ma&longs;s of it, as to compen&longs;ate the | |
| <lb/>exce&longs;&longs;e of the Cones Specificall Gravity above the Gravity of the wa­ | |
| <lb/>ter: and the Scruple ari&longs;eth, becau&longs;e that howbeit in the de&longs;cent | |
| <lb/>made by the Cone, the emergent Point <emph type="italics"/>A S T<emph.end type="italics"/> dimini&longs;heth, whereby | |
| <lb/>there is al&longs;o a diminution of the exce&longs;s of the Cones Gravity above | |
| | |
| | |
| <pb pagenum="459"/>the Gravity of the water, yet the ca&longs;e &longs;tands &longs;o, that the Rampart | |
| <lb/>doth al&longs;o contract it &longs;elf, and the Cylinder contained in it doth de­ | |
| <lb/>mini&longs;h. </s><s>Neverthele&longs;s it &longs;hall be demon&longs;trated, how that the Cone | |
| <lb/><emph type="italics"/>A B D<emph.end type="italics"/> being of any &longs;uppo&longs;ed bigne&longs;&longs;e, and made at the fir&longs;t of a | |
| <lb/>Matter exactly equall in Gravity to the Water, if there may | |
| <lb/>be affixed to it &longs;ome Weight, by means of which it may de&longs;cend to | |
| <lb/>the bottom, when &longs;ubmerged under water, it may al&longs;o by vertue of | |
| <lb/>the Rampart &longs;tay above without &longs;inking.</s></p><p type="main"> | |
| | |
| <s>Let, therefore, the Cone <emph type="italics"/>A B D<emph.end type="italics"/> be of any &longs;uppo&longs;ed greatne&longs;&longs;e, | |
| <lb/>and alike in &longs;pecificall Gravity to the water. </s><s>It is manife&longs;t, that | |
| <lb/>being put lightly into the water, it &longs;hall re&longs;t without de&longs;cending; | |
| <lb/>and it &longs;hall advance above water, the Point | |
| <lb/><figure id="fig279"></figure> | |
| <lb/><emph type="italics"/>AS T,<emph.end type="italics"/> tripple in height to the height of the | |
| <lb/>Rampart <emph type="italics"/>E S<emph.end type="italics"/>: Now, &longs;uppo&longs;e the Cone <emph type="italics"/>A B D<emph.end type="italics"/> | |
| <lb/>more depre&longs;&longs;ed, &longs;o that it advance above wa­ | |
| <lb/>ter, only the Point <emph type="italics"/>A I R,<emph.end type="italics"/> higher by half than | |
| <lb/>the Point <emph type="italics"/>A S T,<emph.end type="italics"/> with the Rampart about it | |
| <lb/><emph type="italics"/>C I R N.<emph.end type="italics"/> And, becau&longs;e, the Cone <emph type="italics"/>A B D<emph.end type="italics"/> is | |
| <lb/>to the Cone <emph type="italics"/>A I R,<emph.end type="italics"/> as the cube of the Line <emph type="italics"/>S T<emph.end type="italics"/> | |
| <lb/>is to the cube of the Line <emph type="italics"/>I R,<emph.end type="italics"/> but the Cylin­ | |
| <lb/>der <emph type="italics"/>E S T O,<emph.end type="italics"/> is to the Cylinder <emph type="italics"/>C I R N,<emph.end type="italics"/> as the Square of <emph type="italics"/>S T<emph.end type="italics"/> to | |
| <lb/>the Square of <emph type="italics"/>I R,<emph.end type="italics"/> the Cone <emph type="italics"/>A S T<emph.end type="italics"/> &longs;hall be Octuple to the Cone | |
| <lb/><emph type="italics"/>A I R,<emph.end type="italics"/> and the Cylinder <emph type="italics"/>E S T O,<emph.end type="italics"/> quadruple to the Cylinder <emph type="italics"/>C I R N<emph.end type="italics"/>: | |
| <lb/>But the Cone <emph type="italics"/>A S T,<emph.end type="italics"/> is equall to the Cylinder E <emph type="italics"/>S T O<emph.end type="italics"/>: Therefore, | |
| <lb/>the Cylinder <emph type="italics"/>C I R N,<emph.end type="italics"/> &longs;hall be double to the Cone <emph type="italics"/>A I R:<emph.end type="italics"/> and the | |
| <lb/>water which might be contained in the Rampart <emph type="italics"/>C I R N,<emph.end type="italics"/> would be | |
| <lb/>double in Ma&longs;s and in Weight to the Cone <emph type="italics"/>A I R,<emph.end type="italics"/> and, therefore, | |
| <lb/>would be able to &longs;u&longs;tain the double of the Weight of the Cone <emph type="italics"/>AIR<emph.end type="italics"/>: | |
| <lb/>Therefore, if to the whole Cone <emph type="italics"/>A B D,<emph.end type="italics"/> there be added as much | |
| <lb/>Weight as the Gravity of the Cone <emph type="italics"/>A I R,<emph.end type="italics"/> that is to &longs;ay, the eighth | |
| <lb/>part of the weight of the Cone <emph type="italics"/>A S T,<emph.end type="italics"/> it al&longs;o &longs;hall be &longs;u&longs;tained by | |
| <lb/>the Rampart <emph type="italics"/>C I R N,<emph.end type="italics"/> but without that it &longs;hall go to the bottome: | |
| <lb/>the Cone <emph type="italics"/>A B D,<emph.end type="italics"/> being, by the addition of the eighth part of the | |
| <lb/>weight of the Cone <emph type="italics"/>A S T,<emph.end type="italics"/> made &longs;pecifically more grave than the | |
| <lb/>water. </s><s>But if the Altitude of the Cone <emph type="italics"/>A I R,<emph.end type="italics"/> were two thirds | |
| <lb/>of the Altitude of the Cone <emph type="italics"/>A S T,<emph.end type="italics"/> the Cone <emph type="italics"/>A S T<emph.end type="italics"/> would be to the | |
| <lb/>Cone <emph type="italics"/>A I R,<emph.end type="italics"/> as twenty &longs;even to eight; and the Cylinder <emph type="italics"/>E S T O,<emph.end type="italics"/> to | |
| <lb/>the Cylinder <emph type="italics"/>C I R N,<emph.end type="italics"/> as nine to four, that is, as twenty &longs;even to | |
| <lb/>twelve; and, therefore, the Cylinder <emph type="italics"/>C I R N,<emph.end type="italics"/> to the Cone <emph type="italics"/>A I R,<emph.end type="italics"/> | |
| <lb/>as twelve to eight; and the exce&longs;s of the Cylinder <emph type="italics"/>C I R N,<emph.end type="italics"/> above | |
| <lb/>the Cone <emph type="italics"/>A I R,<emph.end type="italics"/> to the Cone <emph type="italics"/>A S T,<emph.end type="italics"/> as four to twenty &longs;even: there­ | |
| <lb/>fore if to the Cone <emph type="italics"/>A B D<emph.end type="italics"/> be added &longs;o much weight as is the four | |
| <lb/>twenty &longs;evenths of the weight of the Cone <emph type="italics"/>A S T,<emph.end type="italics"/> which is a little | |
| <lb/>more then its &longs;eventh part, it al&longs;o &longs;hall continue to &longs;wimme, and | |
| | |
| | |
| <pb pagenum="460"/>the height of the emergent Point &longs;hall be double to the height of the | |
| <lb/>Rampart. </s><s>This that hath been demon&longs;trated in Cones, exactly holds | |
| <lb/>in Piramides, although the one or the other &longs;hould be very &longs;harp in | |
| <lb/><arrow.to.target n="marg1524"></arrow.to.target> | |
| <lb/>their Point or Cu&longs;pis: From whence we conclude, that the &longs;ame | |
| <lb/>Accident &longs;hall &longs;o much the more ea&longs;ily happen in all other Figures, | |
| <lb/>by how much the le&longs;s &longs;harp the Tops &longs;hall be, in which they deter­ | |
| <lb/>mine, being a&longs;&longs;i&longs;ted by more &longs;pacious Ramparts.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1524"></margin.target>Natatiou ea&longs;i­ | |
| <lb/>e&longs;t effected in | |
| <lb/>Figures broad | |
| <lb/>toward the top.</s></p><p type="head"> | |
| | |
| <s>THEOREME XIII. | |
| <lb/><arrow.to.target n="marg1525"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1525"></margin.target>All Figures &longs;ink | |
| <lb/>or &longs;wim, upon | |
| <lb/>bathing or not | |
| <lb/>bathing of their | |
| <lb/>tops.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>All Figures, therefore, of whatever greatne&longs;&longs;e, may | |
| <lb/>go, and not go, to the Bottom, according as their Sumi­ | |
| <lb/>ties or Tops &longs;hall be bathed or not bathed.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>And this Accident being common to all &longs;orts of Figures, without | |
| <lb/>exception of &longs;o much as one. </s><s>Figure hath, therefore, no part | |
| <lb/>in the production of this Effect, of &longs;ometimes &longs;inking, and &longs;ome­ | |
| <lb/>times again not &longs;inking, but only the being &longs;ometimes conjoyned | |
| <lb/>to, and &longs;ometimes &longs;eperated from, the &longs;upereminent Air: which | |
| <lb/>cau&longs;e, in fine, who &longs;o &longs;hall rightly, and, as we &longs;ay, with both his | |
| <lb/>Eyes, con&longs;ider this bu&longs;ine&longs;s, will find that it is reduced to, yea, that | |
| <lb/>it really is the &longs;ame with, the true, Naturall and primary cau&longs;e of | |
| <lb/>Natation or Submer&longs;ion; to wit, the exce&longs;s or deficiency of the | |
| <lb/>Gravity of the water, in relation to the Gravity of that Solid Mag­ | |
| <lb/>nitude, that is demitted into the water. </s><s>For like as a Plate of Lead, | |
| <lb/>as thick as the back of a Knife, which being put into the water by it | |
| <lb/>&longs;elf alone goes to the bottom, if upon it you fa&longs;ten a piece of Cork | |
| <lb/>four fingers thick, doth continue afloat, for that now the Solid that | |
| <lb/>is demitted in the water, is not, as before, more grave than the water, | |
| <lb/>but le&longs;s, &longs;o the Board of Ebony, of its own nature more grave than | |
| <lb/>water; and, therefore, de&longs;cending to the bottom, when it is demit­ | |
| <lb/>ted by it &longs;elf alone into the water, if it &longs;hall be put upon the water, | |
| <lb/>conjoyned with an Expanded vail of Air, that together with the | |
| <lb/>Ebony doth de&longs;cend, and that it be &longs;uch, as that it doth make with | |
| <lb/>it a compound le&longs;s grave than &longs;o much water in Ma&longs;s, as equalleth | |
| <lb/>the Ma&longs;s already &longs;ubmerged and depre&longs;&longs;ed beneath the Levell of the | |
| <lb/>waters Surface, it &longs;hall not de&longs;cend any farther, but &longs;hall re&longs;t, for | |
| <lb/>no other than the univer&longs;all and mo&longs;t common cau&longs;e, which is that | |
| <lb/>Solid Magnitudes, le&longs;s grave <emph type="italics"/>in&longs;pecie<emph.end type="italics"/> than the water, go not to the | |
| <lb/>bottom.</s></p><p type="main"> | |
| | |
| <s>So that if one &longs;hould take a Plate of Lead, as for Example, a finger | |
| <lb/>thick, and an handfull broad every way, and &longs;hould attempt to make | |
| <lb/>it &longs;wimme, with putting it lightly on the water, he would lo&longs;e his | |
| <lb/>Labour, becau&longs;e that if it &longs;hould be depre&longs;&longs;ed an Hairs breadth be­ | |
| | |
| | |
| <pb pagenum="461"/>yond the po&longs;&longs;ible Altitude of the Ramparts of water, it would dive | |
| <lb/>and &longs;ink; but if whil&longs;t it is going downwards, one &longs;hould make | |
| <lb/>certain Banks or Ramparts about it, that &longs;hould hinder the do fu&longs;ion | |
| <lb/>of the water upon the &longs;aid Plate, the which Banks &longs;hould ri&longs;e &longs;o | |
| <lb/>high, as that they might be able to contain as much water, as &longs;hould | |
| <lb/>weigh equally with the &longs;aid Plate, it would, without all Que&longs;tion, | |
| <lb/>de&longs;cend no lower, but would re&longs;t, as being &longs;u&longs;tained by vertue of | |
| <lb/>the Air contained within the afore&longs;aid Ramparts: and, in &longs;hort, | |
| <lb/>there would be a Ve&longs;&longs;ell by this means formed with the bottom of | |
| <lb/>Lead. </s><s>But if the thinne&longs;s of the Lead &longs;hall be &longs;uch, that a very | |
| <lb/>&longs;mall height of Rampart would &longs;uffice to contain &longs;o much Air, as might | |
| <lb/>keep it afloat, it &longs;hall al&longs;o re&longs;t without the Artificiall Banks or Ram­ | |
| <lb/>parts, but yet not without the Air, becau&longs;e the Air by it &longs;elf makes | |
| <lb/>Banks &longs;ufficient for a &longs;mall height, to re&longs;i&longs;t the Superfu&longs;ion of the | |
| <lb/>water: &longs;o that that which in this ca&longs;e &longs;wimmes, is as it were a | |
| <lb/>Ve&longs;&longs;ell filled with Air, by vertue of which it continueth afloat.</s></p><p type="main"> | |
| | |
| <s>I will, in the la&longs;t place, with an other Experimeut, attempt to | |
| <lb/>remove all difficulties, if &longs;o be there &longs;hould yet be any doubt le&longs;t in | |
| <lb/>any one, touching the opperation of this ^{*}Continuity of the Air, with </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1526"></arrow.to.target> | |
| <lb/>the thin Plate which &longs;wims, and afterwards put an end to this part of | |
| <lb/>my di&longs;cour&longs;e.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1526"></margin.target>*Or rather Cor­ | |
| <lb/>tiguity,</s></p><p type="main"> | |
| | |
| <s>I &longs;uppo&longs;e my &longs;elf to be que&longs;tioning with &longs;ome of my Oponents.</s></p><p type="main"> | |
| | |
| <s>Whether Figure have any influence upon the encrea&longs;e or diminu­ | |
| <lb/><arrow.to.target n="marg1527"></arrow.to.target> | |
| <lb/>tion of the Re&longs;i&longs;tance in any Weight again&longs;t its being rai&longs;ed in the | |
| <lb/>Air, and I &longs;uppo&longs;e, that I am to maintain the Affirmative, a&longs;&longs;ert­ | |
| <lb/>ing that a Ma&longs;s of Lead, reduced to the Figure of a Ball, &longs;hall be | |
| <lb/>rai&longs;ed with le&longs;s force, then if the &longs;ame had been made into a thinne | |
| <lb/>and broad Plate, becau&longs;e that it in this &longs;pacious Figure, hath a great | |
| <lb/>quantity of Air to penetrate, and in that other, more compacted and | |
| <lb/>contracted very little: and to demon&longs;trate the truth of &longs;uch my O­ | |
| <lb/>pinion, I will hang in a &longs;mall thred fir&longs;t the Ball or Bullet, and put | |
| <lb/>that into the water, tying the thred that upholds it to one end of | |
| <lb/>the Ballance that I hold in the Air, and to the other end I by degrees | |
| <lb/>adde &longs;o much Weight, till that at la&longs;t it brings up the Ball of Lead | |
| <lb/>out of the water: to do which, &longs;uppo&longs;e a Gravity of thirty Ounces | |
| <lb/>&longs;ufficeth; I afcerwards reduce the &longs;aid Lead into a flat and thinne | |
| <lb/>Plate, the which I likewi&longs;e put into the water, &longs;u&longs;pended by three | |
| <lb/>threds, which hold it parallel to the Surface of the water, and put­ | |
| <lb/>ting in the &longs;ame manner, Weights to the other end, till &longs;uch time as | |
| <lb/>the Place comes to be rai&longs;ed and drawn out of the water: I finde | |
| <lb/>that thirty &longs;ix ounces will not &longs;uffice to &longs;eperate it from the water, | |
| <lb/>and rai&longs;e it thorow the Air: and arguing from this Experiment, I af­ | |
| <lb/>firm, that I have fully demon&longs;trated the truth of my Propo&longs;ition. | |
| <lb/></s><s>He re my Oponents de&longs;ires me to look down, &longs;hewing me a thing | |
| | |
| | |
| <pb pagenum="462"/>which I had not before ob&longs;erved, to wit, that in the A&longs;cent of the | |
| <lb/>Plate out of the water, it draws after it another Plate <emph type="italics"/>(if I may &longs;o | |
| <lb/>call it)<emph.end type="italics"/> of water, which before it divides and parts from the inferiour | |
| <lb/>Surface of the Plate of Lead, is rai&longs;ed above the Levell of the other | |
| <lb/>water, more than the thickne&longs;s of the back of a Knife: Then he | |
| <lb/>goeth to repeat the Experiment with the Ball, and makes me &longs;ee, | |
| <lb/>that it is but a very &longs;mall quantity of water, which cleaves to its | |
| <lb/>compacted and contracted Figure: and then he &longs;ubjoynes, that its | |
| <lb/>no wonder, if in &longs;eperating the thinne and broad Plate from the | |
| <lb/>water, we meet with much greater Re&longs;i&longs;tance, than in &longs;eperating the | |
| <lb/>Ball, &longs;ince together with the Plate, we are to rai&longs;e a great quantity of | |
| <lb/>water, which occurreth not in the Ball: He telleth me moreover, | |
| <lb/>how that our Que&longs;tion is, whether the Re&longs;i&longs;tance of Elevation be | |
| <lb/>greater in a dilated Plate of Lead, than in a Ball, and not whether | |
| <lb/>more re&longs;i&longs;teth a Plate of Lead with a great quantity of water, or a | |
| <lb/>Ball with a very little water: He &longs;heweth me in the clo&longs;e, that the | |
| <lb/>putting the Plate and the Ball fir&longs;t into the water, to make proofe | |
| <lb/>thereby of their Re&longs;i&longs;tance in the Air, is be&longs;ides our ca&longs;e, which | |
| <lb/>treats of Elivating in the Air, and of things placed in the Air, and | |
| <lb/>not of the Re&longs;i&longs;tance that is made in the Confines of the Air and | |
| <lb/>water, and by things which are part in Air and part in water: and | |
| <lb/>la&longs;tly, they make me feel with my hand, that when the thinne Plate | |
| <lb/>is in the Air, and free from the weight of the water, it is rai&longs;ed with | |
| <lb/>the very &longs;ame Force that rai&longs;eth the Ball. </s><s>Seeing, and under&longs;tand­ | |
| <lb/>ing the&longs;e things, I know not what to do, unle&longs;s to grant my &longs;elf con­ | |
| <lb/>vinced, and to thank &longs;uch a Friend, for having made me to &longs;ee that | |
| <lb/>which I never till then ob&longs;erved: and, being adverti&longs;ed by this &longs;ame | |
| <lb/>Accident, to tell my Adver&longs;aries, that our Que&longs;tion is, whether a | |
| <lb/>Board and a Ball of Ebony, equally go to the bottom in water, and | |
| <lb/>not a Ball of Ebony and a Board of Ebony, joyned with another | |
| <lb/>flat Body of Air: and, farthermore, that we &longs;peak of &longs;inking, and | |
| <lb/>not &longs;inking to the bottom, in water, and not of that which happeneth | |
| <lb/>in the Confines of the water and Air to Bodies that be part in the | |
| <lb/>Air, and part in the water; nor much le&longs;s do we treat of the greater | |
| <lb/>or le&longs;&longs;er Force requi&longs;ite in &longs;eperating this or that Body from the Air; | |
| <lb/>not omitting to tell them, in the la&longs;t place, that the Air doth re&longs;i&longs;t, | |
| <lb/>and gravitate downwards in the water, ju&longs;t &longs;o much as the water (if | |
| <lb/>I may &longs;o &longs;peak) gravitates and re&longs;i&longs;ts upwards in the Air, and that the | |
| <lb/>&longs;ame force is required to &longs;inke a Bladder under water, that is full of | |
| <lb/>Air, as to rai&longs;e it in the Air, being full of water, removing the con­ | |
| <lb/>&longs;ideration of the weight of that Filme or Skinne, and confidering the | |
| <lb/>water and the Air only. </s><s>And it is likewi&longs;e true, that the &longs;ame Force | |
| <lb/>is required to &longs;ink a Cup or &longs;uch like Ve&longs;&longs;ell under water, whil&longs;t it is | |
| <lb/>full of Air, as to rai&longs;e it above the Superficies of the water, keeping | |
| | |
| | |
| <pb pagenum="463"/>it with the mouth downwards; whil&longs;t it is full of water, which is | |
| <lb/>con&longs;trained in the &longs;ame manner to follow the Cup which contains it, | |
| <lb/>and to ri&longs;e above the other water into the Region of the Air, as the | |
| <lb/>Air is forced to follow the &longs;ame Ve&longs;&longs;ell under the Surface of the wa­ | |
| <lb/>ter, till that in this ca&longs;e the water, &longs;urmounting the brimme of the | |
| <lb/>Cup, breaks in, driving thence the Air, and in that ca&longs;e, the &longs;aid | |
| <lb/>brimme coming out of the water, and arriving to the Confines of the | |
| <lb/>Air, the water falls down, and the Air &longs;ub-enters to fill the cavity of | |
| <lb/>the Cup: upon which en&longs;ues, that he no le&longs;s tran&longs;gre&longs;&longs;es the Arti­ | |
| <lb/>cles of the <emph type="italics"/>Convention,<emph.end type="italics"/> who produceth a Plate conjoyned with much | |
| <lb/>Air, to &longs;ee if it de &longs;eend to the bottom in water, then he that makes | |
| <lb/>proof of the Re&longs;i&longs;tance again&longs;t Elevation in Air with a Plate of Lead, | |
| <lb/>joyned with a like quantity of water.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1527"></margin.target>An Experi­ | |
| <lb/>ment of the op­ | |
| <lb/>peration of Fi­ | |
| <lb/>gures, in en­ | |
| <lb/>crea&longs;ing or le&longs;­ | |
| <lb/>&longs;ening of the | |
| <lb/>Airs Re&longs;i&longs;tance | |
| <lb/>of Divi&longs;ion.</s></p><p type="main"> | |
| | |
| <s>I have &longs;aid all that I could at pre&longs;ent think of, to maintain the | |
| <lb/><arrow.to.target n="marg1528"></arrow.to.target> | |
| <lb/>A&longs;&longs;ertion I have undertook. </s><s>It remains, that I examine that which | |
| <lb/><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> hath writ of this matter towards the end of his Book <emph type="italics"/>De Cælo<emph.end type="italics"/>; | |
| <lb/>wherein I &longs;hall note two things: the one that it being true as hath | |
| <lb/><arrow.to.target n="marg1529"></arrow.to.target> | |
| <lb/>been demon&longs;trated, that Figure hath nothing to do about the moving | |
| <lb/>or not moving it &longs;elf upwards or downwards, it &longs;eemes that <emph type="italics"/>Aristotle<emph.end type="italics"/> | |
| <lb/>at his fir&longs;t falling upon this Sp. </s><s>culation, was of the &longs;ame opinion, as | |
| <lb/>in my opinion may be collected from the examination of his words. | |
| <lb/></s><s>Tis true, indeed, that in e&longs;&longs;aying afterwards to render a rea&longs;on of | |
| <lb/>&longs;uch effect, as not having in my conceit hit upon the right, (which | |
| <lb/>in the &longs;econd place I will examine) it &longs;eems that he is brought to | |
| <lb/>admit the largene&longs;&longs;e of Figure, to be intere&longs;&longs;ed in this operation. | |
| <lb/></s><s>As to the fir&longs;t particuler, hear the preci&longs;e words of <emph type="italics"/>Aristotle.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1528"></margin.target><emph type="italics"/>Ari&longs;totles<emph.end type="italics"/> opi­ | |
| <lb/>nion touching | |
| <lb/>the Operation | |
| <lb/>of Figure ex­ | |
| <lb/>amined.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1529"></margin.target><emph type="italics"/>Ari&longs;tot de Cælo,<emph.end type="italics"/> | |
| <lb/>Lib. 4. Cap. | |
| | |
| 66.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Figures are not the Cau&longs;es of moving &longs;imply upwards or downwards,<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1530"></arrow.to.target> | |
| <lb/><emph type="italics"/>but of moving more &longs;lowly or &longs;wiftly, and by what means this comes to | |
| <lb/>pa&longs;s, it is not difficult to &longs;ee.<emph.end type="italics"/></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1530"></margin.target><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> makes | |
| <lb/>not Figure the | |
| <lb/>cau&longs;e of Motion | |
| <lb/>ab&longs;olutely, but | |
| <lb/>of &longs;wi&longs;t or &longs;low | |
| <lb/>motion,</s></p><p type="main"> | |
| | |
| <s>Here fir&longs;t I note, that the terms being four, which fall under the | |
| <lb/>pre&longs;ent con&longs;ideration, namely, Motion, Re&longs;t, Slowly and Swiftly: | |
| <lb/><arrow.to.target n="marg1531"></arrow.to.target> | |
| <lb/>And <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> naming Figures as Cau&longs;es of Tardity and Velocity, ex­ | |
| <lb/>cluding them from being the Cau&longs;e of ab&longs;olute and &longs;imple Motion, | |
| <lb/>it &longs;eems nece&longs;&longs;ary, that he exclude them on the other &longs;ide, from being | |
| <lb/>the Cau&longs;e of Re&longs;t, &longs;o that his meaning is this. </s><s>Figures are not the | |
| <lb/>Cau&longs;es of moving or not moving ab&longs;olutely, but of moving quickly | |
| <lb/>or &longs;lowly: and, here, if any &longs;hould &longs;ay the mind of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> is to | |
| <lb/>exclude Figures from being Cau&longs;es of Motion, but yet not from | |
| <lb/>being Cau&longs;es of Re&longs;t, &longs;o that the &longs;ence would be to remove from | |
| <lb/>Figures, there being the Cau&longs;es of moving &longs;imply, but yet not there | |
| <lb/>being Cau&longs;es of Re&longs;t, I would demand, whether we ought with | |
| <lb/><emph type="italics"/>Aristotle<emph.end type="italics"/> to under&longs;tand, that all Figures univer&longs;ally, are, in &longs;ome | |
| <lb/>manner, the cau&longs;es of Re&longs;t in tho&longs;e Bodies, which otherwi&longs;e would | |
| <lb/>move, or el&longs;e &longs;ome particular Figures only, as for Example, broad | |
| | |
| | |
| <pb pagenum="464"/>and thinne Figures: If all indifferently, then every Body &longs;hall re&longs;t: | |
| <lb/>becau&longs;e every Body hath &longs;ome Figure, which is fal&longs;e: but if &longs;ome | |
| <lb/>particular Figures only may be in &longs;ome manner a Cau&longs;e of Re&longs;t, as, | |
| <lb/>for Example, the broad, then the others would be in &longs;ome manner | |
| <lb/>the Cau&longs;es of Motion: for if from &longs;eeing &longs;ome Bodies of a contracted | |
| <lb/>Figure move, which after dilated into Plates re&longs;t, may be inferred, | |
| <lb/>that the Amplitude of Figure hath a part in the Cau&longs;e of that Re&longs;t; | |
| <lb/>&longs;o from &longs;eeing &longs;uch like Figures re&longs;t, which afterwards contracted | |
| <lb/>move, it may with the &longs;ame rea&longs;on be affirmed, that the united and | |
| <lb/>contracted Figure, hath a part in cau&longs;ing Motion, as the remover of | |
| <lb/>that which impeded it: The which again is directly oppo&longs;ite to what | |
| <lb/><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> &longs;aith, namely, that Figures are not the Cau&longs;es of Motion. | |
| <lb/></s><s>Be&longs;ides, if <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> had admitted and not excluded Figures from be­ | |
| <lb/>ing Cau&longs;es of not moving in &longs;ome Bodies, which moulded into ano­ | |
| <lb/>ther Figure would move, he would have impertinently propounded | |
| <lb/>in a dubitative manner, in the words immediately following, whence | |
| <lb/>it is, that the large and thinne Plates of Lead or Iron, re&longs;t upon the | |
| <lb/>water, &longs;ince the Cau&longs;e was apparent, namely, the Amplitude of | |
| <lb/>Figure. </s><s>Let us conclude, therefore, that the meaning of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> | |
| <lb/>in this place is to affirm, that Figures are not the Cau&longs;es of ab&longs;olutely | |
| <lb/>moving or not moving, but only of moving &longs;wiftly or &longs;lowly: which | |
| <lb/>we ought the rather to believe, in regard it is indeed a me&longs;t true con­ | |
| <lb/>ceipt and opinion. </s><s>Now the mird of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> being &longs;uch, and ap­ | |
| <lb/>pearing by con&longs;equence, rather contrary at the fir&longs;t &longs;ight, then fa­ | |
| <lb/>vourable to the a&longs;&longs;ertion of the Oponents, it is nece&longs;&longs;ary, that their | |
| <lb/>Interpretation be not exactly the &longs;ame with that, but &longs;uch, as being | |
| <lb/>in part under&longs;tood by &longs;ome of them, and in part by others, was &longs;et | |
| <lb/>down: and it may ea&longs;ily be indeed &longs;o, being an Interpretation | |
| <lb/>con&longs;onent to the &longs;ence of the more famous Interpretors, which is, | |
| <lb/>that the Adverbe <emph type="italics"/>Simply<emph.end type="italics"/> or <emph type="italics"/>Ab&longs;olutely,<emph.end type="italics"/> put in the Text, orght not to | |
| <lb/>be joyned to the Verbe to <emph type="italics"/>Move,<emph.end type="italics"/> but with the Noun <emph type="italics"/>Cau&longs;es<emph.end type="italics"/>: &longs;o that | |
| <lb/>the purport of <emph type="italics"/>Ari&longs;totles<emph.end type="italics"/> words, is to affirm, That Figures are not the | |
| <lb/>Cau&longs;es ab&longs;olutely of moving or not moving, but yet are Cau&longs;es <emph type="italics"/>Se­ | |
| <lb/>cundum quid, viz<emph.end type="italics"/> in &longs;ome &longs;ort; by which means, they are called | |
| <lb/>Auxiliary and Concomitant Cau&longs;es: and this Propo&longs;ition is received | |
| <lb/>and a&longs;&longs;erted as true by <emph type="italics"/>Signor Buonamico Lib.<emph.end type="italics"/> 5. <emph type="italics"/>Cap.<emph.end type="italics"/> 28. where he | |
| <lb/>thus writes. <emph type="italics"/>There are other Cau&longs;es concomitant, by which &longs;ome | |
| <lb/>things float, and others &longs;ink, among which the Figures of Bodies hath | |
| <lb/>the fir&longs;t place,<emph.end type="italics"/> &c.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1531"></margin.target>Lib. 4. Cap. | |
| | |
| 61 | |
| <lb/>Text. </s><s>42.</s></p><p type="main"> | |
| | |
| <s>Concerning this Propo&longs;ition, I meet with many doubts and diffi­ | |
| <lb/>culties, for which me thinks the words of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> are not capable of | |
| <lb/>&longs;uch a con&longs;truction and &longs;ence, and the difficulties are the&longs;e.</s></p><p type="main"> | |
| | |
| <s>Fir&longs;t in the order and di&longs;po&longs;ure of the words of <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> the par­ | |
| <lb/>ticle <emph type="italics"/>Simpliciter,<emph.end type="italics"/> or if you will <emph type="italics"/>ab&longs;oluté,<emph.end type="italics"/> is conjoyned with the Verb | |
| | |
| | |
| <pb pagenum="465"/><emph type="italics"/>to move,<emph.end type="italics"/> and &longs;eperated from the Noun <emph type="italics"/>Cau&longs;es,<emph.end type="italics"/> the which is a great | |
| <lb/>pre&longs;umption in my favour, &longs;eeing that the writing and the Text | |
| <lb/>&longs;aith, Figures are not the Cau&longs;e of moving &longs;imply upwards or | |
| <lb/>downwards, but of quicker or &longs;lower Motion: and, &longs;aith not, | |
| <lb/>Figures are not &longs;imply the Cau&longs;es of moving upwards or down­ | |
| <lb/>wards, and when the words of a Text receive, tran&longs;po&longs;ed, a &longs;ence | |
| <lb/>different from that which they found, taken in the order wherein | |
| <lb/>the Author di&longs;po&longs;eth them, it is not convenient to inverte them. | |
| <lb/></s><s>And who will affirm that <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> de&longs;iring to write a Propo&longs;ition, | |
| <lb/>would di&longs;po&longs;e the words in &longs;uch &longs;ort, that they &longs;hould import a | |
| <lb/>different, nay, a contrary &longs;ence? </s><s>contrary, I &longs;ay, becau&longs;e under­ | |
| <lb/>&longs;tood as they are written; they &longs;ay, that Figures are not the | |
| <lb/>Cau&longs;es of Motion, but inverted, they &longs;ay, that Figures are the | |
| <lb/>Cau&longs;es of Motion, &c.</s></p><p type="main"> | |
| | |
| <s>Moreover, if the intent of <emph type="italics"/>Aristotle<emph.end type="italics"/> had been to &longs;ay, that Figures | |
| <lb/>are not &longs;imply the Cau&longs;es of moving upwards or downwards, but | |
| <lb/>only Cau&longs;es <emph type="italics"/>Secundum quid,<emph.end type="italics"/> he would not have adjoyned tho&longs;e | |
| <lb/>words, <emph type="italics"/>but they are Cau&longs;es of the more &longs;wift or &longs;low Motion<emph.end type="italics"/>; yea, the | |
| <lb/>&longs;ubjoining this would have been not only &longs;uperfluous but fal&longs;e, for | |
| <lb/>that the whole tenour of the Propo&longs;ition would import thus much. | |
| <lb/></s><s>Figures are not the ab&longs;olute Cau&longs;es of moving upwards or down­ | |
| <lb/>wards, but are the ab&longs;olute Cau&longs;e of the &longs;wift or &longs;low Motion; | |
| <lb/>which is not true: becau&longs;e the primary Cau&longs;es of greater or le&longs;&longs;er | |
| <lb/>Velocity, are by <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> in the 4th of his <emph type="italics"/>Phy&longs;icks, Text.<emph.end type="italics"/> 71. attri­ | |
| <lb/>buted to the greater or le&longs;&longs;er Gravity of Moveables, compared a­ | |
| <lb/>mong them&longs;elves, and to the greater or le&longs;&longs;er Re&longs;i&longs;tance of the | |
| <lb/><emph type="italics"/>Medium's,<emph.end type="italics"/> depending on their greater or le&longs;s Cra&longs;&longs;itude: and the&longs;e | |
| <lb/>are in&longs;erted by <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> as the primary Cau&longs;es; and the&longs;e two only | |
| <lb/>are in that place nominated: and Figure comes afterwards to be | |
| <lb/>con&longs;idered, <emph type="italics"/>Text.<emph.end type="italics"/> 74. rather as an In&longs;trumentall Cau&longs;e of the force | |
| <lb/>of the Gravity, the which divides either with the Figure, or with | |
| <lb/>the <emph type="italics"/>Impetus<emph.end type="italics"/>; and, indeed, Figure by it &longs;elf without the force of | |
| <lb/>Gravity or Levity, would opperate nothing.</s></p><p type="main"> | |
| | |
| <s>Iadde, that if <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> had an opinion that Figure had been in | |
| <lb/>&longs;ome &longs;ort the Cau&longs;e of moving or not moving, the inqui&longs;ition | |
| <lb/>which he makes immediately in a doubtfull manner, whence it | |
| <lb/>comes, that a Plate of Lead flotes, would have been impertinent; | |
| <lb/>for if but ju&longs;t before he had &longs;aid, that Figure was in a certain &longs;ort | |
| <lb/>the Cau&longs;e of moving or not moving, he needed not to call in | |
| <lb/>Que&longs;tion, by what Cau&longs;e the Plate of Lead &longs;wims, and then a&longs;cri­ | |
| <lb/>bing the Cau&longs;e to its Figure; and framing a di&longs;cour&longs;e in this manner. | |
| <lb/></s><s>Figure is a Cau&longs;e <emph type="italics"/>Secundum quid<emph.end type="italics"/> of not &longs;inking: but, now, if it be | |
| <lb/>doubted, for what Cau&longs;e a thin Plate of Lead goes not to the bottom; | |
| <lb/>it &longs;hall be an&longs;wered, that that proceeds from its Figure: a di&longs;cour&longs;e | |
| | |
| | |
| <pb pagenum="466"/>which would be indecent in a Child, much more in <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/>; For | |
| <lb/>where is the occa&longs;ion of doubting? </s><s>And who &longs;ees not, that if <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> | |
| <lb/>had held, that Figure was in &longs;ome &longs;ort a Cau&longs;e of Natation, he | |
| <lb/>would without the lea&longs;t He&longs;itation have writ; That Figure is in a | |
| <lb/>certain &longs;ort the Cau&longs;e of Natation, and therefore the Plate of Lead | |
| <lb/>in re&longs;pect of its large and expatiated Figure &longs;wims; but if we take | |
| <lb/>the propo&longs;ition of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> as I &longs;ay, and as it is writte n, and as in­ | |
| <lb/>deed it is true, the en&longs;uing words come in very oppo&longs;itely, as well in | |
| <lb/>the introduction of &longs;wift and &longs;low, as in the que&longs;tion, which very | |
| <lb/>pertinently offers it &longs;elf, and would &longs;ay thus much.</s></p><p type="main"> | |
| | |
| <s>Figures are not the Cau&longs;e of moving or not moving &longs;imply up­ | |
| <lb/>wards or downwards, but of moving more quickly or &longs;lowly: But if | |
| <lb/>it be &longs;o, the Cau&longs;e is doubtfull, whence it proceeds, that a Plate of | |
| <lb/>Lead or of Iron broad and thin doth &longs;wim, &c. </s><s>And the occa&longs;ion of | |
| <lb/>the doubt is obvious, becau&longs;e it &longs;eems at the fir&longs;t glance, that the | |
| <lb/>Figure is the Cau&longs;e of this Natation, &longs;ince the &longs;ame Lead, or a le&longs;s | |
| <lb/>quantity, but in another Figure, goes to the bottom, and we have | |
| <lb/>already affirmed, that the Figure hath no &longs;hare in this effect.</s></p><p type="main"> | |
| | |
| <s>La&longs;tly, if the intent of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> in this place had been to &longs;ay, | |
| <lb/>that Figures, although not ab&longs;olutely, are at lea&longs;t in &longs;ome mea&longs;ure | |
| <lb/>the Cau&longs;e of moving or not moving: I would have it con&longs;idered, | |
| <lb/>that he names no le&longs;s the Motion upwards, than the other down­ | |
| <lb/>wards: and becau&longs;e in exemplifying it afterwards, he produceth | |
| <lb/>no other Experiments than of a Plate of Lead, and Board of Ebony, | |
| <lb/>Matters that of their own Nature go to the bottom, but by vertue | |
| <lb/>(as our Adver&longs;aries &longs;ay) of their Figure, re&longs;t afloat; it is &longs;it that | |
| <lb/>they &longs;hould produce &longs;ome other Experiment of tho&longs;e Matters, which | |
| <lb/>by their Nature &longs;wims, but retained by their Figure re&longs;t at the | |
| <lb/>bottom. </s><s>But &longs;ince this is impo&longs;&longs;ible to be done, we conclude, that | |
| <lb/><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> in this place, hath not attributed any action to the Figure | |
| <lb/>of &longs;imply moving or not moving.</s></p><p type="main"> | |
| | |
| <s>But though he hath exqui&longs;itely Philo&longs;ophiz'd, in inve&longs;tigating | |
| <lb/>the &longs;olution of the doubts he propo&longs;eth, yet will I not undertake | |
| <lb/>to maintain, rather various difficulties, that pre&longs;ent them&longs;elves | |
| <lb/>unto me, give me occa&longs;ion of &longs;u&longs;pecting that he hath not entirely | |
| <lb/>di&longs;plaid unto us, the true Cau&longs;e of the pre&longs;ent Conclu&longs;ion: which | |
| <lb/>difficulties I will propound one by one, ready to change opinion, | |
| <lb/>when ever I am &longs;hewed, that the Truth is different from what I &longs;ay; | |
| <lb/>to the confe&longs;&longs;ion whereof I am much more inclinable than to contra­ | |
| <lb/>diction. | |
| <lb/><arrow.to.target n="marg1532"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1532"></margin.target><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> erred | |
| <lb/>in affirming a | |
| <lb/>Needle dimitted | |
| <lb/>long wayes to | |
| <lb/>&longs;ink.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> having propounded the Que&longs;tion, whence it proceeds, | |
| <lb/>that broad Plates of Iron or Lead, float or &longs;wim; he addeth (as | |
| <lb/>it were &longs;trengthening the occa&longs;ion of doubting) fora&longs;much as other | |
| <lb/>things, le&longs;s, and le&longs;s grave, be they round or long, as for in&longs;tance a | |
| | |
| | |
| <pb pagenum="467"/>Needle go to the bottom. </s><s>Now I here doubt, or rather am certain, | |
| <lb/>that a Needle put lightly upon the water, re&longs;ts afloat, no le&longs;s than the | |
| <lb/>thin Plates of Iron or Lead. </s><s>I cannot believe, albeit it hath been | |
| <lb/>told me, that &longs;ome to defend <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> &longs;hould &longs;ay, that he intends a | |
| <lb/>Needle demitted not longwayes but endwayes, and with the Point | |
| <lb/>downwards; neverthele&longs;s, not to leave them &longs;o much as this, though | |
| <lb/>very weak refuge, and which in my judgement <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> him&longs;elf | |
| <lb/>would refu&longs;e, I &longs;ay it ought to be under&longs;tood, that the Needle mu&longs;t | |
| <lb/>be demitted, according to the Dimen&longs;ion named by <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> which | |
| <lb/>is the length: becau&longs;e, if any other Dimen&longs;ion than that which is | |
| <lb/>named, might or ought to be taken, I would &longs;ay, that even the Plates | |
| <lb/>of Iron and Lead, &longs;ink to the bottom, if they be put into the water | |
| <lb/>edgewayes and not flatwayes. </s><s>But becau&longs;e <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> &longs;aith, broad | |
| <lb/>Figures go not to the bottom, it is to be under&longs;tood, being demitted | |
| <lb/>broadwayes: and, therefore, when he &longs;aith, long Figures as a | |
| <lb/>Needle, albeit light, re&longs;t not afloat, it ought to be under&longs;tood of | |
| <lb/>them when demitted longwayes.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Morcover, to &longs;ay that<emph.end type="italics"/> Ari&longs;totle <emph type="italics"/>is to be under&longs;tood of the Needle de­ | |
| <lb/>mitted with the Point downwards, is to father upon him a great imper­ | |
| <lb/>tinency; for in this place he &longs;aith, that little Particles of Lead or Iron, | |
| <lb/>if they be round or long as a Needle, do &longs;ink to the bottome; &longs;o that by | |
| <lb/>his Opinion, a Particle or &longs;mall Grain of Iron cannot &longs;wim: and if he | |
| <lb/>thus believed, what a great folly would it be to &longs;ubjoyn, that neither | |
| <lb/>would a Needle demitted endwayes &longs;wim? </s><s>And what other is &longs;uch a | |
| <lb/>Needle, but many &longs;uch like Graines accumulated one upon another? </s><s>It | |
| <lb/>was too unworthy of &longs;uch a man to &longs;ay, that one &longs;ingle Grain of Iron could | |
| <lb/>not &longs;wim, and that neither can it &longs;wim, though you put a hundred more | |
| <lb/>upon it.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>La&longs;tly, either <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> believed, that a Needle demitted long­ | |
| <lb/>wayes upon the water, would &longs;wim, or he believed that it would | |
| <lb/>not &longs;wim: If he believed it would not &longs;wim, he might well &longs;peak | |
| <lb/>as indeed he did; but if he believed and knew that it would &longs;loat, | |
| <lb/>why, together with the dubious Problem of the Natation of broad | |
| <lb/>Figure, though of ponderous Matter, hath he not al&longs;o introduced | |
| <lb/>the Que&longs;tion; whence it proceeds, that even long and &longs;lender Fi­ | |
| <lb/>gures, howbeit of Iron or Lead do &longs;wim? </s><s>And the rather, for that | |
| <lb/>the occa&longs;ion of doubting &longs;eems greater in long and narrow Figures, | |
| <lb/>than in broad and thin, as from <emph type="italics"/>Aristotles<emph.end type="italics"/> not having doubted of it, | |
| <lb/>is manife&longs;ted.</s></p><p type="main"> | |
| | |
| <s>No le&longs;&longs;er an inconvenience would they fa&longs;ten upon <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> who | |
| <lb/>in his defence &longs;hould &longs;ay, that he means a Needle pretty thick, and | |
| <lb/>not a &longs;mall one; for take it for granted to be intended of a &longs;mall one | |
| | |
| | |
| <pb pagenum="468"/>and it &longs;hall &longs;uffice to reply, that he believed that it would &longs;wim; | |
| <lb/>and I will again charge him with having avoided a more wonderfull | |
| <lb/>and intricate Probleme, and introduced the more facile and le&longs;s | |
| <lb/>wonderfull.</s></p><p type="main"> | |
| | |
| <s>We &longs;ay freely therefore; that <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> did hold, that only the | |
| <lb/>broad Figure did &longs;wim, but the long and &longs;lender, &longs;uch as a Needle, | |
| <lb/>not. </s><s>The which neverthele&longs;s is fal&longs;e, as it is al&longs;o fal&longs;e in round | |
| <lb/>Bodies: becau&longs;e, as from what hath been predemon&longs;trated, may be ga­ | |
| <lb/>thered, little Balls of Lead and Iron, do in like manner &longs;wim.</s></p><p type="main"> | |
| | |
| <s>He propo&longs;eth likewi&longs;e another Conclu&longs;ion, which likewi&longs;e &longs;eems </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1533"></arrow.to.target> | |
| <lb/>different from the truth, and it is, That &longs;ome things, by rea&longs;on of | |
| <lb/>their littlene&longs;s fly in the Air, as the &longs;mall du&longs;t of the Earth, and the | |
| <lb/>thin leaves of beaten Gold: but in my Opinion, Experience &longs;hews | |
| <lb/>us, that that happens not only in the Air, but al&longs;o in the water, in | |
| <lb/>which do de&longs;cend, even tho&longs;e Particles or Atomes of Earth, that | |
| <lb/>di&longs;tur be it, who&longs;e minuity is &longs;uch, that they are not de&longs;ervable, &longs;ave | |
| <lb/>only when they are many hundreds together. </s><s>Therefore, the du&longs;t | |
| <lb/>of the Earth, and beaten Gold, do not any way &longs;u&longs;tain them&longs;elves | |
| <lb/>in the Air, but de&longs;cend downwards, and only fly to and again in | |
| <lb/>the &longs;ame, when &longs;trong Windes rai&longs;e them, or other agitations of the | |
| <lb/>Air commove them: and this al&longs;o happens in the commotion of the | |
| <lb/>water, which rai&longs;eth its Sand from the bottom, and makes it muddy. | |
| <lb/></s><s>But <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> cannot mean this impediment of the commotion, of | |
| <lb/>which he makes no mention, nor names other than the lightne&longs;s of | |
| <lb/>&longs;uch Minutiæ or Atomes, and the Re&longs;i&longs;tance of the Cra&longs;&longs;itudes of the | |
| <lb/>Water and Air, by which we &longs;ee, that he &longs;peakes of a calme, and | |
| <lb/>not di&longs;turbed and agitated Air: but in that ca&longs;e, neither Gold nor | |
| <lb/>Earth, be they never &longs;o &longs;mall, are &longs;u&longs;tained, but &longs;peedily de&longs;cend. | |
| <lb/><arrow.to.target n="marg1534"></arrow.to.target></s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1533"></margin.target><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> af­ | |
| <lb/>fir meth &longs;ome | |
| <lb/>Bodies volatile | |
| <lb/>for their Minu­ | |
| <lb/>ity, Text. </s><s>42.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1534"></margin.target><emph type="italics"/>Democritus<emph.end type="italics"/> pla­ | |
| <lb/>ced the Cau&longs;e of | |
| <lb/>Natation in | |
| <lb/>certain &longs;iery A­ | |
| <lb/>tomes.</s></p><p type="main"> | |
| | |
| <s>He pa&longs;&longs;eth next to confute <emph type="italics"/>Democritus,<emph.end type="italics"/> which, by his Te&longs;timony | |
| <lb/>would have it, that &longs;ome Fiery Atomes, which continually a&longs;cend | |
| <lb/>through the water, do &longs;pring upwards, and &longs;u&longs;tain tho&longs;e grave Bodies, | |
| <lb/>which are very broad, and that the narrow de&longs;cend to the bottom, </s></p><p type="main"> | |
| | |
| <s><arrow.to.target n="marg1535"></arrow.to.target> | |
| <lb/>for that but a &longs;mall quantity of tho&longs;e Atomes, encounter and re&longs;i&longs;t | |
| <lb/>them.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1535"></margin.target><emph type="italics"/>Ari&longs;tot. </s><s>De Cœlo<emph.end type="italics"/> | |
| <lb/>lib. | |
| | |
| 4. cap. | |
| | |
| 6. | |
| <lb/>text. </s><s>43.</s></p><p type="main"> | |
| | |
| <s>I &longs;ay, <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> confutes this po&longs;ition, &longs;aying, that that &longs;hould | |
| <lb/><arrow.to.target n="marg1536"></arrow.to.target> | |
| <lb/>much more occurre in the Air, as the &longs;ame <emph type="italics"/>Democritus<emph.end type="italics"/> in&longs;tances a­ | |
| <lb/>gain&longs;t him&longs;elf, but after he had moved the objection, he &longs;lightly re­ | |
| <lb/>&longs;olves it, with &longs;aying, that tho&longs;e Corpu&longs;cles which a&longs;cend in the Air, | |
| <lb/>make not their <emph type="italics"/>Impetus<emph.end type="italics"/> conjunctly. </s><s>Here I will not &longs;ay, that the | |
| <lb/><arrow.to.target n="marg1537"></arrow.to.target> | |
| <lb/>rea&longs;on alledged by <emph type="italics"/>Democritus<emph.end type="italics"/> is true, but I will only &longs;ay, it &longs;eems | |
| <lb/>in my judgement, that it is not wholly confuted by <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> whil&longs;t he | |
| <lb/>&longs;aith, that were it true, that the calid a&longs;cending Atomes, &longs;hould | |
| <lb/>&longs;u&longs;tain Bodies grave, but very broad, it would much more be done | |
| <lb/>in the Air, than in Water, for that haply in the Opinion of <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> | |
| | |
| | |
| <pb pagenum="469"/>the &longs;aid calid Atomes a&longs;cend with much greater Force and Velocity | |
| <lb/>through the Air, than through the water. </s><s>And if this be &longs;o, as I veri­ | |
| <lb/>ly believe it is, the Objection of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> in my judgement &longs;eems to | |
| <lb/>give occa&longs;ion of &longs;u&longs;pecting, that he may po&longs;&longs;ibly be deceived in more | |
| <lb/>than one particular: Fir&longs;t, becau&longs;e tho&longs;e calid Atomes, (whether | |
| <lb/>they be Fiery Corpu&longs;cles, or whether they be Exhalations, or in | |
| <lb/>&longs;hort, whatever other matter they be, that a&longs;cends upwards through | |
| <lb/>the Air) cannot be believed to mount fa&longs;ter through Air, than | |
| <lb/>through water: but rather on the contrary, they peradventure move | |
| <lb/>more impetuou&longs;ly through the water, than through the Air, as hath | |
| <lb/>been in part demon&longs;trated above. </s><s>And here I cannot finde the rea­ | |
| <lb/>&longs;on, why <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> &longs;eeing, that the de&longs;eending Motion of the &longs;ame | |
| <lb/>Moveable, is more &longs;wift in Air, than in water, hath not adverti&longs;ed | |
| <lb/>us, that from the contrary Motion, the contrary &longs;hould nece&longs;&longs;arily | |
| <lb/>follow; to wit, that it is more &longs;wift in the water, than in the Air: for | |
| <lb/>&longs;ince that the Moveable which de&longs;cendeth, moves &longs;wifter through | |
| <lb/>the Air, than through the water, if we &longs;hould &longs;uppo&longs;e its Gravity | |
| <lb/>gradually to dimini&longs;h, it would fir&longs;t become &longs;uch, that de&longs;cending | |
| <lb/>&longs;wiftly through the Air, it would de&longs;cend but &longs;lowly through the | |
| <lb/>water: and then again, it might be &longs;uch, that de&longs;cending in the | |
| <lb/>Air, it &longs;hould a&longs;cend in the water: and being made yet le&longs;s grave, | |
| <lb/>it &longs;hall a&longs;cend &longs;wiftly through the water, and yet de&longs;cend likewi&longs;e | |
| <lb/>through the Air: and in &longs;hort, before it can begin to a&longs;cend, though | |
| <lb/>but &longs;lowly through the Air, it &longs;hall a&longs;cend &longs;wiftly through the water: | |
| <lb/>how then is it true, that a&longs;cending Moveables move &longs;wifter through | |
| <lb/>the Air, than through the water?</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1536"></margin.target><emph type="italics"/>Democritus<emph.end type="italics"/> con­ | |
| <lb/>futed by <emph type="italics"/>Ari­ | |
| <lb/>&longs;totle,<emph.end type="italics"/> text 43.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1537"></margin.target><emph type="italics"/>Ari&longs;totles<emph.end type="italics"/> con­ | |
| <lb/>futation of <emph type="italics"/>De­ | |
| <lb/>mocritus<emph.end type="italics"/> refuted | |
| <lb/>by the Author.</s></p><p type="main"> | |
| | |
| <s>That which hath made <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> believe, the Motion of A&longs;cent to be | |
| <lb/>&longs;wifter in Air, than in water, was fir&longs;t, the having referred the | |
| <lb/>Cau&longs;es of &longs;low and quick, as well in the Motion of A&longs;cent, as of | |
| <lb/>De&longs;cent, only to the diver&longs;ity of the Figures of the Moveable, and to | |
| <lb/>the more or le&longs;s Re&longs;i&longs;tance of the greater or le&longs;&longs;er Cra&longs;&longs;itude, or Ra­ | |
| <lb/>rity of the <emph type="italics"/>Medium<emph.end type="italics"/>; not regarding the compari&longs;on of the Exce&longs;&longs;es | |
| <lb/>of the Gravities of the Moveables, and of the <emph type="italics"/>Mediums<emph.end type="italics"/>: the which | |
| <lb/>notwith&longs;tanding, is the mo&longs;t principal point in this affair: for if the | |
| <lb/>augmentation and diminution of the Tardity or Velocity, &longs;hould | |
| <lb/>have only re&longs;pect to the Den&longs;ity or Rarity of the <emph type="italics"/>Medium,<emph.end type="italics"/> every Body | |
| <lb/>that de&longs;cends in Air, would de&longs;cend in water: becau&longs;e whatever | |
| <lb/>difference is found between the Cra&longs;&longs;itude of the water, and that of | |
| <lb/>the Air, may well be found between the Velocity of the &longs;ame Move­ | |
| <lb/>able in the Air, and &longs;ome other Velocity: and this &longs;hould be its | |
| <lb/>proper Velocity in the water, which is ab&longs;olutely fal&longs;e. </s><s>The other | |
| <lb/>occa&longs;ion is, that he did believe, that like as there is a po&longs;itive and in­ | |
| <lb/>trin&longs;ecall Quality, whereby Elementary Bodies have a propen&longs;ion | |
| <lb/>of moving towards the Centre of the Earth, &longs;o there is another like­ | |
| | |
| | |
| <pb pagenum="470"/>wi&longs;e intrin&longs;ecall, whereby &longs;ome of tho&longs;e Bodies have an <emph type="italics"/>Impetus<emph.end type="italics"/> of | |
| <lb/><arrow.to.target n="marg1538"></arrow.to.target> | |
| <lb/>flying the Centre, and moving upwards: by Vertue of which in­ | |
| <lb/>trin&longs;e call Principle, called by him Levity, the Moveables which have | |
| <lb/>that &longs;ame Motion more ea&longs;ily penetrate the more &longs;ubtle <emph type="italics"/>Medium,<emph.end type="italics"/> | |
| <lb/>than the more den&longs;e: but &longs;uch a Propo&longs;ition appears likewi&longs;e un­ | |
| <lb/>certain, as I have above hinted in part, and as with Rea&longs;ons and | |
| <lb/>Experiments, I could demon&longs;trate, did not the pre&longs;ent Argument im­ | |
| <lb/>portune me, or could I di&longs;patch it in few words.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1538"></margin.target>Lib. 4. Cap. | |
| | |
| 5.</s></p><p type="main"> | |
| | |
| <s>The Objection therefore of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> again&longs;t <emph type="italics"/>Democritus,<emph.end type="italics"/> whil&longs;t | |
| <lb/>he &longs;aith, that if the Fiery a&longs;cending Atomes &longs;hould &longs;u&longs;tain Bodies | |
| <lb/>grave, but of a di&longs;tended Figure, it would be more ob&longs;ervable in | |
| <lb/>the Air than in the water, becau&longs;e &longs;uch Corpu&longs;cles move &longs;wifter in | |
| <lb/>that, than in this, is not good; yea the contrary would evene, for | |
| <lb/>that they a&longs;cend more &longs;lowly through the Air: and, be&longs;ides their | |
| <lb/>moving &longs;lowly, they a&longs;cend, not united together, as in the water, | |
| <lb/>but di&longs;continue, and, as we &longs;ay, &longs;catter: And, therefore, as | |
| <lb/><emph type="italics"/>Democritus<emph.end type="italics"/> well replyes, re&longs;olving the in&longs;tance they make not their | |
| <lb/>pu&longs;h or <emph type="italics"/>Impetus<emph.end type="italics"/> conjunctly.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> in the &longs;econd place, deceives him&longs;elf, whil&longs;t he will | |
| <lb/>have the &longs;aid grave Bodies to be more ea&longs;ily &longs;u&longs;tained by the &longs;aid | |
| <lb/>Fiery a&longs;cending Atomes in the Air than in the Water: not ob&longs;erv­ | |
| <lb/>ing, that the &longs;aid Bodies are much more grave in that, than in this, | |
| <lb/>and that &longs;uch a Body weighs ten pounds in the Air, which will not | |
| <lb/>in the water weigh 1/2 an ounce; how can it then be more ea&longs;ily | |
| <lb/>&longs;u&longs;tained in the Air, than in the Water?</s></p><p type="main"> | |
| | |
| <s>Let us conclude, therefore, that <emph type="italics"/>Democritus<emph.end type="italics"/> hath in this particular | |
| <lb/>better Philo&longs;ophated than <emph type="italics"/>Ari&longs;totle.<emph.end type="italics"/> But yet will not I affirm, that <emph type="italics"/>De-<emph.end type="italics"/> | |
| <lb/><arrow.to.target n="marg1539"></arrow.to.target> | |
| <lb/><emph type="italics"/>mocritus<emph.end type="italics"/> hath rea&longs;on'd rightly, but I rather &longs;ay, that there is a ma­ | |
| <lb/>nife&longs;t Experiment that overthrows his Rea&longs;on, and this it is, That | |
| <lb/>if it were true, that calid a&longs;cending Atomes &longs;hould uphold a Body, | |
| <lb/>that if they did not hinder, would go to the bottom, it would follow, | |
| <lb/>that we may find a Matter very little &longs;uperiour in Gravity to the | |
| <lb/>water, the which being reduced into a Ball, or other contracted | |
| <lb/>Figure, &longs;hould go to the bottom, as encountring but few Fiery A­ | |
| <lb/>tomes; and which being di&longs;tended afterwards into a dilated and | |
| <lb/>thin Plate, &longs;hould come to be thru&longs;t upwards by the impul&longs;ion of a | |
| <lb/>great Multitude of tho&longs;e Corpu&longs;cles, and at la&longs;t carried to the very | |
| <lb/>Surface of the water: which wee &longs;ee not to happen; Experience | |
| <lb/>&longs;hewing us, that a Body <emph type="italics"/>v. </s><s>gra.<emph.end type="italics"/> of a Sphericall Figure, which very | |
| <lb/>hardly, and with very great lea&longs;ure goeth to the bottom, will re&longs;t | |
| <lb/>there, and will al&longs;o de&longs;cend thither, being reduced into what&longs;oever | |
| <lb/>other di&longs;tended Figure. </s><s>We mu&longs;t needs &longs;ay then, either that in the | |
| <lb/>water, there are no &longs;uch a&longs;cending Fiery Atoms, or if that &longs;uch there | |
| <lb/>be, that they are not able to rai&longs;e and lift up any Plate of a Matter, | |
| | |
| | |
| <pb pagenum="471"/>that without them would go to the bottom: Of which two Pofitions, | |
| <lb/>I e&longs;teem the &longs;econd to be true, under&longs;tanding it of water, con&longs;tituted | |
| <lb/>in its naturall Coldne&longs;s. </s><s>But if we take a Ve&longs;&longs;el of Gla&longs;s, or Bra&longs;s, | |
| <lb/>or any other hard matter, full of cold water, within which is put a | |
| <lb/>Solid of a flat or concave Figure, but that in Gravity exceeds the | |
| <lb/>water &longs;o little, that it goes &longs;lowly to the bottom; I &longs;ay, that putting | |
| <lb/>&longs;ome burning Coals under the &longs;aid Ve&longs;&longs;el, as &longs;oon as the new Fiery | |
| <lb/>Atomes &longs;hall have penetrated the &longs;ub&longs;tance of the Ve&longs;&longs;el, they &longs;hall | |
| <lb/>without doubt, a&longs;cend through that of the water, and thru&longs;ting a­ | |
| <lb/>gain&longs;t the fore&longs;aid Solid, they &longs;hall drive it to the Superficies, and | |
| <lb/>there detain it, as long as the incur&longs;ions of the &longs;aid Corpu&longs;cles &longs;hall | |
| <lb/>la&longs;t, which cea&longs;ing after the removall of the Fire, the Solid being a­ | |
| <lb/>bandoned by its &longs;upporters, &longs;hall return to the bottom.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1539"></margin.target><emph type="italics"/>Democritus<emph.end type="italics"/> con­ | |
| <lb/>futed by the | |
| <lb/>Authour.</s></p><p type="main"> | |
| | |
| <s>But <emph type="italics"/>Democritus<emph.end type="italics"/> notes, that this Caufe only takes place when we | |
| <lb/>treat of rai&longs;ing and &longs;u&longs;taining of Plates of Matters, but very little | |
| <lb/>heavier than the water, or extreamly thin: but in Matters very | |
| <lb/>grave, and of &longs;ome thickne&longs;s, as Plates of Lead or other Mettal, that | |
| <lb/>&longs;ame Effect wholly cea&longs;eth: In Te&longs;timony of which, let's ob&longs;erve | |
| <lb/>that &longs;uch Plates, being rai&longs;ed by the Fiery Atomes, a&longs;cend through | |
| <lb/>all the depth of the water, and &longs;top at the Confines of the Air, &longs;till | |
| <lb/>&longs;taying under water: but the Plates of the Opponents &longs;tay not, but | |
| <lb/>only when they have their upper Superficies dry, nor is there any | |
| <lb/>means to be u&longs;ed, that when they are within the water, they may | |
| <lb/>not &longs;ink to the bottom. </s><s>The cau&longs;e, therefore, of the Supernatation | |
| <lb/>of the things of which <emph type="italics"/>Democritus<emph.end type="italics"/> &longs;peaks is one, and that of the Super­ | |
| <lb/>natation of the things of which we &longs;peak is another. </s><s>But, returning | |
| <lb/><arrow.to.target n="marg1540"></arrow.to.target> | |
| <lb/>to <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> methinks that he hath more weakly confuted <emph type="italics"/>Democritus,<emph.end type="italics"/> | |
| <lb/>than <emph type="italics"/>Democritus<emph.end type="italics"/> him&longs;elf hath done: For <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> having propounded | |
| <lb/>the Objection which he maketh again&longs;t him, and oppo&longs;ed him with | |
| <lb/>&longs;aying, that if the calid a&longs;cendent Corpu&longs;cles were tho&longs;e that rai&longs;ed | |
| <lb/>the thin Plate, much more then would &longs;uch a Solid be rai&longs;ed and | |
| <lb/>born upwards through the Air, it &longs;heweth that the de&longs;ire in <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> | |
| <lb/>to detect <emph type="italics"/>Democritus,<emph.end type="italics"/> was predominate over the exqui&longs;itene&longs;s of Solid | |
| <lb/>Philo&longs;ophizing: which de&longs;ire of his he hath di&longs;covered in other oc­ | |
| <lb/>ca&longs;ions, and that we may not digre&longs;s too far from this place, in the | |
| <lb/>Text precedent to this Chapter which we have in hand; where he | |
| <lb/><arrow.to.target n="marg1541"></arrow.to.target> | |
| <lb/>attempts to confute the &longs;ame <emph type="italics"/>Democritus,<emph.end type="italics"/> for that he, not content­ | |
| <lb/>ing him&longs;elf with names only, had e&longs;&longs;ayed more particularly to de­ | |
| <lb/>clare what things Gravity and Levity were; that is, the Cau&longs;es of | |
| <lb/>de&longs;cending and a&longs;cending, (and had introduced Repletion and Va­ | |
| <lb/>cuity) a&longs;cribing this to Fire, by which it moves upwards, and that to | |
| <lb/>the Earth, by which it de&longs;cends; afterwards attributing to the | |
| <lb/>Air more of Fire, and to the water more of Earth. </s><s>But <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> | |
| <lb/>de&longs;iring a po&longs;itive Cau&longs;e, even of a&longs;cending Motion, and not as <emph type="italics"/>Plato,<emph.end type="italics"/> | |
| | |
| | |
| <pb pagenum="472"/>or the&longs;e others, a &longs;imple negation, or privation, &longs;uch as Vacuity | |
| <lb/><arrow.to.target n="marg1542"></arrow.to.target> | |
| <lb/>would be in reference to Repletion, argueth again&longs;t <emph type="italics"/>Democritus<emph.end type="italics"/> and | |
| <lb/>&longs;aith: If it be true, as you &longs;uppo&longs;e, then there &longs;hall be a great Ma&longs;s | |
| <lb/>of water, which &longs;hall have more of Fire, than a &longs;mall Ma&longs;s of Air, | |
| <lb/>and a great Ma&longs;s of Air, which &longs;hall have more of Earth than a lit­ | |
| <lb/>tle Ma&longs;s of water, whereby it would en&longs;ue, that a great Ma&longs;s of Air, | |
| <lb/>&longs;hould come more &longs;wiftly downwards, than a little quantity of | |
| <lb/>water: But that is never in any ca&longs;e &longs;oever: Therefore <emph type="italics"/>Democritus<emph.end type="italics"/> | |
| <lb/>di&longs;cour&longs;eth erroneou&longs;ly.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1540"></margin.target><emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> &longs;hews | |
| <lb/>his de&longs;ire of | |
| <lb/>finding <emph type="italics"/>Demo­ | |
| <lb/>critus<emph.end type="italics"/> in an Er­ | |
| <lb/>ror, to exceed | |
| <lb/>that of di&longs;co­ | |
| <lb/>veting Truth.</s></p><p type="margin"> | |
| | |
| | |
| <s><margin.target id="marg1541"></margin.target>Cap. | |
| | |
| | |
| 5. Text 41.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1542"></margin.target>Id. </s><s>ibid.</s></p><p type="main"> | |
| | |
| <s>But in my opinion, the Doctrine of <emph type="italics"/>Democritus,<emph.end type="italics"/> is not by this alle­ | |
| <lb/>gation overthrown, but if I erre not, the manner of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> deduction | |
| <lb/>either concludes not, or if it do conclude any thing, it may with e­ | |
| <lb/>quall force be re&longs;tored again&longs;t him&longs;elf. <emph type="italics"/>Democritus<emph.end type="italics"/> will grant to | |
| <lb/><emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> that there may be a great Ma&longs;s of Air taken, which con­ | |
| <lb/>tains more Earth, than a &longs;mall quantity of water, but yet will deny, | |
| <lb/>that &longs;uch a Ma&longs;s of Air, &longs;hall go fa&longs;ter downwards than a little water, | |
| <lb/>and that for many rea&longs;ons. </s><s>Fir&longs;t, becau&longs;e if the greater quantity | |
| <lb/>of Earth, contained in the great Ma&longs;s of Air, ought to cau&longs;e a greater | |
| <lb/>Velocity than a le&longs;s quantity of Earth, contained in a little quantity | |
| <lb/>of water, it would be nece&longs;&longs;ary, fir&longs;t, that it were true, that a | |
| <lb/>greater Ma&longs;s of pure Earth, &longs;hould move more &longs;wiftly than a le&longs;s: | |
| <lb/>But this is fal&longs;e, though <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> in many places affirms it to be true: | |
| <lb/>becau&longs;e not the greater ab&longs;olute, but the greater &longs;pecificall Gravity, | |
| <lb/><arrow.to.target n="marg1543"></arrow.to.target> | |
| <lb/>is the cau&longs;e of greater Velocity: nor doth a Ball of Wood, weigh­ | |
| <lb/>ing ten pounds, de&longs;cend more &longs;wiftly than one weighing ten Ounces, | |
| <lb/>and that is of the &longs;ame Matter: but indeed a Bullet of Lead of four | |
| <lb/>Ounces, de&longs;cendeth more &longs;wiftly than a Ball of Wood of twenty | |
| <lb/>Pounds: becau&longs;e the Lead is more grave <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> than the Wood. | |
| <lb/></s><s>Therefore, its not nece&longs;&longs;ary, that a great Ma&longs;s of Air, by rea&longs;on of | |
| <lb/>the much Earth contained in it, do de&longs;cend more &longs;wiftly than a little | |
| <lb/><arrow.to.target n="marg1544"></arrow.to.target> | |
| <lb/>Ma&longs;s of water, but on the contrary, any what&longs;oever Ma&longs;s of water, | |
| <lb/>&longs;hall move more &longs;wiftly than any other of Air, by rea&longs;on the partici­ | |
| <lb/>pation of the terrene parts <emph type="italics"/>in &longs;pecie<emph.end type="italics"/> is greater in the water, than in the | |
| <lb/>Air. </s><s>Let us note, in the &longs;econd place, how that in multiplying the | |
| <lb/>Ma&longs;s of the Air, we not only multiply that which is therein of terrene, | |
| <lb/>but its Fire al&longs;o: whence the Cau&longs;e of a&longs;cending, no le&longs;s encrea&longs;eth, | |
| <lb/>by vertue of the Fire, than that of de&longs;cending on the account of its | |
| <lb/>multiplied Earth. </s><s>It was requi&longs;ite in increa&longs;ing the greatne&longs;s of the | |
| <lb/>Air, to multiply that which it hath of terrene only, leaving its Fire | |
| <lb/>in its fir&longs;t &longs;tate, for then the terrene parts of the augmented Air, | |
| <lb/>overcoming the terrene parts of the &longs;mall quantity of water, it might | |
| <lb/>with more probability have been pretended, that the great quanti­ | |
| <lb/>ty of Air, ought to de&longs;cend with a greater <emph type="italics"/>Impetus,<emph.end type="italics"/> than the little | |
| <lb/>quantity of water.</s></p> | |
| | |
| | |
| <pb pagenum="467"/><p type="margin"> | |
| | |
| <s><margin.target id="marg1543"></margin.target>The greater | |
| <lb/>Specificall, not | |
| <lb/>the greater ab­ | |
| <lb/>&longs;olute Gravity, | |
| <lb/>is the Cau&longs;e of | |
| <lb/>Velocity.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1544"></margin.target>Any Ma&longs;s of | |
| <lb/>water &longs;hal move | |
| <lb/>more &longs;wiftly, | |
| <lb/>than any of Air, | |
| <lb/>and why.</s></p><p type="main"> | |
| | |
| <s>Therefore, the Fallacy lyes more in the Di&longs;cour&longs;e of <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> than | |
| <lb/>in that of <emph type="italics"/>Democritus,<emph.end type="italics"/> who with &longs;everall other Rea&longs;ons might oppo&longs;e | |
| <lb/><emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> and alledge; If it be true, that the extreame Elements be | |
| <lb/>one &longs;imply grave, and the other &longs;imply light, and that the mean | |
| <lb/>Elements participate of the one, and of the other Nature; but the | |
| <lb/>Air more of Levity, and the water more of Gravity, then there &longs;hall | |
| <lb/>be a great Ma&longs;s of Air, who&longs;e Gravity &longs;hall exceed the Gravity of a | |
| <lb/>little quantity of water; and therefore &longs;uch a Ma&longs;s of Air &longs;hall de­ | |
| <lb/>&longs;cend more &longs;wiftly than that little water: But that is never &longs;een to | |
| <lb/>occurr: Therefore its not true, that the mean Elements do partici­ | |
| <lb/>pate of the one, and the other quality. </s><s>This argument is fallacious, | |
| <lb/>no le&longs;s than the other again&longs;t <emph type="italics"/>Democritus.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>La&longs;tly, <emph type="italics"/>Aristotle<emph.end type="italics"/> having &longs;aid, that if the Po&longs;ition of <emph type="italics"/>Democritus<emph.end type="italics"/> | |
| <lb/>were true, it would follow, that a great Ma&longs;s of Air &longs;hould move | |
| <lb/>more &longs;wiftly than a &longs;mall Ma&longs;s of water, and afterwards &longs;ubjoyned, | |
| <lb/>that that is never &longs;een in any Ca&longs;e: methinks others may become de­ | |
| <lb/>&longs;irous to know of him in what place this &longs;hould evene, which he de­ | |
| <lb/>duceth again&longs;t <emph type="italics"/>Democritus,<emph.end type="italics"/> and what Experiment teacheth us, that | |
| <lb/>it never falls out &longs;o. </s><s>To &longs;uppo&longs;e to &longs;ee it in the Element of water, | |
| <lb/>or in that of the Air is vain, becau&longs;e neither doth water through | |
| <lb/>water, nor Air through Air move, nor would they ever by any | |
| <lb/>whatever participation others a&longs;&longs;ign them, of Earth or of Fire: the | |
| <lb/>Earth, in that it is not a Body fluid, and yielding to the mobility of | |
| <lb/>other Bodies, is a mo&longs;t improper place and <emph type="italics"/>Medium<emph.end type="italics"/> for &longs;uch an Ex­ | |
| <lb/>periment: <emph type="italics"/>Vacuum,<emph.end type="italics"/> according to the &longs;ame <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> him&longs;elf, there | |
| <lb/>is none, and were there, nothing would move in it: there remaine | |
| <lb/>the Region of Fire, but being &longs;o far di&longs;tant from us, what Experi­ | |
| <lb/>ment can a&longs;&longs;ure us, or hath a&longs;&longs;ertained <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> in &longs;uch &longs;ort, that he | |
| <lb/>&longs;hould as of a thing mo&longs;t obvious to &longs;ence, affirm what he produ­ | |
| <lb/>ceth in confutation of <emph type="italics"/>Democritus,<emph.end type="italics"/> to wit, that a great Ma&longs;s of Air, | |
| <lb/>is moved no &longs;wifter than a little one of water? </s><s>But I will dwell no | |
| <lb/>longer upon this matter, whereon I have &longs;poke &longs;ufficiently: but | |
| <lb/>leaving <emph type="italics"/>Democritus,<emph.end type="italics"/> I return to the Text of <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> wherein he | |
| <lb/>goes about to render the true rea&longs;on, how it comes to pa&longs;s, that the | |
| <lb/>thin Plates of Iron or Lead do &longs;wim on the water; and, moreover, | |
| <lb/>that Gold it &longs;elf being beaten into thin Leaves, not only &longs;wims in | |
| <lb/>water, but flyeth too and again in the Air. </s><s>He &longs;uppo&longs;eth that of | |
| <lb/><arrow.to.target n="marg1545"></arrow.to.target> | |
| <lb/>Continualls, &longs;ome are ea&longs;ily divi&longs;ible, others not: and that of the | |
| <lb/>ea&longs;ily divi&longs;ible, &longs;ome are more &longs;o, and &longs;ome le&longs;s: and the&longs;e he | |
| <lb/>affirms we &longs;hould e&longs;teem the Cau&longs;es. </s><s>He addes that that is ea&longs;ily | |
| <lb/>divi&longs;ible, which is well terminated, and the more the more divi&longs;ible, | |
| <lb/>and that the Air is more &longs;o, than the water, and the water than the | |
| <lb/>Earth. </s><s>And, la&longs;tly, he &longs;uppo&longs;eth that in each kind, the le&longs;&longs;e quan­ | |
| <lb/>tity is ea&longs;lyer divided and broken than the greater.</s></p> | |
| | |
| | |
| <pb pagenum="474"/><p type="margin"> | |
| | |
| <s><margin.target id="marg1545"></margin.target><emph type="italics"/>De Cœlo<emph.end type="italics"/> l. </s><s>4. c. | |
| <lb/></s><s>6. t. </s><s>44.</s></p><p type="main"> | |
| | |
| <s>Here I note, that the Conclu&longs;ions of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> in generall are all | |
| <lb/>true, but methinks, that he applyeth them to particulars, in which | |
| <lb/>they have no place, as indeed they have in others, as for Example, | |
| <lb/>Wax is more ea&longs;ily divi&longs;ible than Lead, and Lead than Silver, in­ | |
| <lb/>a&longs;much as Wax receives all the terms more ea&longs;iler than Lead, and | |
| <lb/>Lead than Silver. </s><s>Its true, moreover, that a little quantity of Sil­ | |
| <lb/>ver is ea&longs;lier divided than a great Ma&longs;s: and all the&longs;e Propo&longs;itions | |
| <lb/>are true, becau&longs;e true it is, that in Silver, Lead and Wax, there | |
| <lb/>is &longs;imply a Re&longs;i&longs;tance again&longs;t Divi&longs;ion, and where there is the ab&longs;o­ | |
| <lb/>lute, there is al&longs;o the re&longs;pective. </s><s>But if as well in water as in Air, | |
| <lb/>there be no Renitence again&longs;t &longs;imple Divi&longs;ion, how can we &longs;ay, that | |
| <lb/>the water is ea&longs;lier divided than the Air? </s><s>We know not how to ex­ | |
| <lb/>tricate our &longs;elves from the Equivocation: whereupon I return to | |
| <lb/>an&longs;wer, that Re&longs;i&longs;tance of ab&longs;olute Divi&longs;ion is one thing, and Re­ | |
| <lb/>&longs;i&longs;tance of Divi&longs;ion made with &longs;uch and &longs;uch Velocity is another. | |
| <lb/></s><s>But to produce Re&longs;t, and to abate the Motion, the Re&longs;i&longs;tance of | |
| <lb/>ab&longs;olute Divi&longs;ion is nece&longs;&longs;ary; and the Re&longs;i&longs;tance of &longs;peedy Di­ | |
| <lb/>vi&longs;ion, cau&longs;eth not Re&longs;t, but &longs;lowne&longs;s of Motion. </s><s>But that as well | |
| <lb/>in the Air, as in water, there is no Re&longs;i&longs;tance of &longs;imple Divi&longs;ion, is | |
| <lb/>manife&longs;t, for that there is not found any Solid Body which divides | |
| <lb/>not the Air, and al&longs;o the water: and that beaten Gold, or &longs;mall | |
| <lb/>du&longs;t, are not able to &longs;uperate the Re&longs;i&longs;tance of the Air, is contrary | |
| <lb/>to that which Experience &longs;hews us, for we &longs;ee Gold and Du&longs;t to go | |
| <lb/>waving to and again in the Air, and at la&longs;t to de&longs;cend down­ | |
| <lb/>wards, and to do the &longs;ame in the water, if it be put therein, and &longs;e­ | |
| <lb/>parated from the Air. </s><s>And, becau&longs;e, as I &longs;ay, neither the water, | |
| <lb/>nor the Air do re&longs;i&longs;t &longs;imple Divi&longs;ion, it cannot be &longs;aid, that the water | |
| <lb/>re&longs;i&longs;ts more than the Air. </s><s>Nor let any object unto me, the Exam­ | |
| <lb/>ple of mo&longs;t light Bodies, as a Feather, or a little of the pith of El­ | |
| <lb/>der, or water-reed that divides the Air and not the water, and from | |
| <lb/>this infer, that the Ait is ea&longs;lier divi&longs;ible than the water; for I &longs;ay | |
| <lb/>unto them, that if they do well ob&longs;erve, they &longs;hall &longs;ee the &longs;ame | |
| <lb/><arrow.to.target n="marg1546"></arrow.to.target> | |
| <lb/>Body likewi&longs;e divide the Continuity of the water, and &longs;ubmerge in | |
| <lb/>part, and in &longs;uch a part, as that &longs;o much water in Ma&longs;s would weigh | |
| <lb/>as much as the whole Solid. </s><s>And if they &longs;hal yet per&longs;i&longs;t in their doubt, | |
| <lb/>that &longs;uch a Solid &longs;inks not through inability to divide the water, I will | |
| <lb/>return them this reply, that if they put it under water, and then let it | |
| <lb/>go, they &longs;hall &longs;ee it divide the water, and pre&longs;ently a&longs;cend with no le&longs;s | |
| <lb/>celerity, than that with which it divided the Air in de&longs;cending: &longs;o that | |
| <lb/>to &longs;ay that this Solid a&longs;cends in the Air, but that coming to the water, | |
| <lb/>it cea&longs;eth its Motion, and therefore the water is more difficult to be | |
| <lb/>divided, concludes nothing: for I, on the contrary, will propo&longs;e them | |
| <lb/>a piece of Wood, or of Wax, which ri&longs;eth from the bottom of the | |
| <lb/>water, and ea&longs;ily divides its Re&longs;i&longs;tance, which afterwards being arri­ | |
| | |
| | |
| <pb pagenum="475"/>ved at the Air, &longs;tayeth there, and hardly toucheth it; whence I may | |
| <lb/>aswell &longs;ay, that the water is more ea&longs;ier divided than the Air</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1546"></margin.target><emph type="italics"/>Archimed. </s><s>De | |
| <lb/>In&longs;ident, humi<emph.end type="italics"/> lib. | |
| <lb/></s><s>2. prop. | |
| | |
| 1.</s></p><p type="main"> | |
| | |
| <s>I will not on this occa&longs;ion forbear to give warning of another fal­ | |
| <lb/>lacy of the&longs;e per&longs;ons, who attribute the rea&longs;on of &longs;inking or &longs;wimming | |
| <lb/>to the greater or le&longs;&longs;e Re&longs;i&longs;tance of the Cra&longs;&longs;itude of the water again&longs;t | |
| <lb/>Divi&longs;ion, making u&longs;e of the example of an Egg, which in &longs;weet water | |
| <lb/>goeth to the bottom, but in &longs;alt water &longs;wims; and alledging for the | |
| <lb/>cau&longs;e thereof, the faint Re&longs;i&longs;tance of fre&longs;h water again&longs;t Divi&longs;ion, and | |
| <lb/>the &longs;trong Re&longs;i&longs;tance of &longs;alt water But if I mi&longs;take not, from the &longs;ame | |
| <lb/>Experiment, we may aswell deduce the quite contrary; namely, that | |
| <lb/>the fre&longs;h water is more den&longs;e, and the &longs;alt more tenuous and &longs;ubtle, | |
| <lb/>&longs;ince an Egg from the bottom of &longs;alt water &longs;peedily a&longs;cends to the | |
| <lb/>top, and divides its Re&longs;i&longs;tance, which it cannot do in the fre&longs;h, in who&longs;e | |
| <lb/>bottom it &longs;tays, being unable to ri&longs;e upwards. </s><s>Into &longs;uch like perplex­ | |
| <lb/>ities, do fal&longs;e Principles Lead men: but he that rightly Philo&longs;ophating, | |
| <lb/>&longs;hall acknowledge the exce&longs;&longs;es of the Gravities of the Moveables and | |
| <lb/>of the Mediums, to be the Cau&longs;es of tho&longs;e effects, will &longs;ay, that the | |
| <lb/>Egg &longs;inks to the bottom in fre&longs;h water, for that it is more grave than | |
| <lb/>it, and &longs;wimeth in the &longs;alt, for that its le&longs;s grave than it: and &longs;hall | |
| <lb/>without any ab&longs;urdity, very &longs;olidly e&longs;tabli&longs;h his Conclu&longs;ions.</s></p><p type="main"> | |
| | |
| <s>Therefore the rea&longs;on totally cea&longs;eth, that <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> &longs;ubjoyns in the | |
| <lb/><arrow.to.target n="marg1547"></arrow.to.target> | |
| <lb/>Text &longs;aying; The things, therefore, which have great breadth remain | |
| <lb/>above, becau&longs;e they comprehend much, and that which is greater, | |
| <lb/>is not ea&longs;ily divided. </s><s>Such di&longs;cour&longs;ing cea&longs;eth, I &longs;ay, becau&longs;e its not | |
| <lb/>true, that there is in water or in Air any Re&longs;i&longs;tance of Divi&longs;ion; be­ | |
| <lb/>&longs;ides that the Plate of Lead when it &longs;tays, hath already divided and | |
| <lb/>penetrated the Cra&longs;&longs;itude of the water, and profounded it &longs;elf ten or | |
| <lb/>twelve times more than its own thickne&longs;s: be&longs;ides that &longs;uch Re&longs;i&longs;tance | |
| <lb/>of Divi&longs;ion, were it &longs;uppo&longs;ed to be in the water, could not rationally | |
| <lb/>be affirmed to be more in its &longs;uperiour parts than in the middle, and | |
| <lb/>lower: but if there were any difference, the inferiour &longs;hould be the | |
| <lb/>more den&longs;e, &longs;o that the Plate would be no le&longs;s unable to penetrate | |
| <lb/>the lower, than the &longs;uperiour parts of the water; neverthele&longs;s we &longs;ee | |
| <lb/>that no &longs;ooner do we wet the &longs;uperious Superficies of the Board or | |
| <lb/>thin Piece of Wood, but it precipitatly, and without any reten&longs;ion, | |
| <lb/>de&longs;cends to the bottom.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1547"></margin.target>Text 45.</s></p><p type="main"> | |
| | |
| <s>I believe not after all this, that any (thinking perhaps thereby to | |
| <lb/>defend <emph type="italics"/>Aristotle<emph.end type="italics"/>) will &longs;ay, that it being true, that the much water re­ | |
| <lb/>&longs;i&longs;ts more than the little, the &longs;aid Board being put lower de&longs;cendeth, | |
| <lb/>becau&longs;e there remaineth a le&longs;s Ma&longs;s of water to be divided by it: be­ | |
| <lb/>cau&longs;e if after the having &longs;een the &longs;ame Board &longs;wim in four Inches of | |
| <lb/>water, and al&longs;o after that in the &longs;ame to &longs;ink, he &longs;hall try the &longs;ame | |
| <lb/>Experiment upon a profundity of ten or twenty fathom water, he | |
| <lb/>&longs;hall &longs;ee the very &longs;elf &longs;ame effect. </s><s>And here I will take occa&longs;ion to | |
| | |
| | |
| <pb pagenum="476"/>remember, for the removall of an Error that is too common; That | |
| <lb/>that Ship or other what&longs;oever Body, that on the depth of an hundred | |
| <lb/>or a thou&longs;and fathom, &longs;wims with &longs;ubmerging only &longs;ix fathom of its | |
| <lb/>own height, [<emph type="italics"/>or in the Sea dialect, that draws &longs;ix fathom water<emph.end type="italics"/>] &longs;hall | |
| <lb/>&longs;wim in the &longs;ame manner in water, that hath but &longs;ix fathom and half | |
| <lb/><arrow.to.target n="marg1548"></arrow.to.target> | |
| <lb/>an Inch of depth. </s><s>Nor do I on the other &longs;ide, think that it can be | |
| <lb/>&longs;aid, that the &longs;uperiour parts of the water are the more den&longs;e, al­ | |
| <lb/>though a mo&longs;t grave Authour hath e&longs;teemed the &longs;uperiour water in | |
| <lb/>the Sea to be &longs;o, grounding his opinion upon its being more &longs;alt, than | |
| <lb/>that at the bottom: but I doubt the Experiment, whether hitherto | |
| <lb/>in taking the water from the bottom, the Ob&longs;ervatour did not light | |
| <lb/>upon &longs;ome &longs;pring of fre&longs;h water there &longs;pouting up: but we plainly | |
| <lb/>&longs;ee on the contrary, the fre&longs;h Waters of Rivers to dilate them&longs;elves | |
| <lb/>for &longs;ome miles beyond their place of meeting with the &longs;alt water of | |
| <lb/>the Sea, without de&longs;cending in it, or mixing with it, unle&longs;s by the | |
| <lb/>intervention of &longs;ome commotion or turbulency of the Windes.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1548"></margin.target>A Ship that | |
| <lb/>in 100 Fathome | |
| <lb/>water draweth | |
| <lb/>6 Fathome, &longs;hall | |
| <lb/>float in 6 Fa­ | |
| <lb/>thome and 1/2 an | |
| <lb/>Inch of depth.</s></p><p type="main"> | |
| | |
| <s>But returning to <emph type="italics"/>Aristotle,<emph.end type="italics"/> I &longs;ay, that the breadth of Figure hath | |
| <lb/>nothing to do in this bu&longs;ine&longs;s more or le&longs;s, becau&longs;e the &longs;aid Plate of | |
| <lb/><arrow.to.target n="marg1549"></arrow.to.target> | |
| <lb/>Lead, or other Matter, cut into long Slices, &longs;wim neither more nor | |
| <lb/>le&longs;s; and the &longs;ame &longs;hall the Slices do, being cut anew into little | |
| <lb/>pieces, becau&longs;e its not the breadth but the thickne&longs;s that operates in | |
| <lb/>this bu&longs;ine&longs;s. </s><s>I &longs;ay farther, that in ca&longs;e it were really true, that the | |
| <lb/><arrow.to.target n="marg1550"></arrow.to.target> | |
| <lb/>Renitence to Divi&longs;ion were the proper Cau&longs;e of &longs;wimming, the Fi­ | |
| <lb/>gures more narrow and &longs;hort, would much better &longs;wim than the more | |
| <lb/>&longs;pacious and broad, &longs;o that augmenting the breadth of the Figure, | |
| <lb/>the facility of &longs;upernatation will be demini&longs;hed, and decrea&longs;ing, that | |
| <lb/>this will encrea&longs;e.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1549"></margin.target>Thickne&longs;s not | |
| <lb/>breadth of Fi­ | |
| <lb/>gure to be re­ | |
| <lb/>&longs;pected in Na­ | |
| <lb/>tation.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1550"></margin.target>Were Reni­ | |
| <lb/>tence the cau&longs;e | |
| <lb/>of Natation, | |
| <lb/>breadth of Fi­ | |
| <lb/>gure would | |
| <lb/>hinder the | |
| <lb/>&longs;wiming of Bo­ | |
| <lb/>dies.</s></p><p type="main"> | |
| | |
| <s>And for declaration of what I &longs;ay, con&longs;ider that when a thin Plate | |
| <lb/>of Lead de&longs;cends, dividing the water, the Divi&longs;ion and di&longs;continu­ | |
| <lb/>ation is made between the parts of the water, invironing the perime­ | |
| <lb/>ter or Circumference of the &longs;aid Plate, and according to the big­ | |
| <lb/>ne&longs;s greater or le&longs;&longs;er of that circuit, it hath to divide a greater or | |
| <lb/>le&longs;&longs;er quantity of water, &longs;o that if the circuit, &longs;uppo&longs;e of a Board, | |
| <lb/>be ten Feet in &longs;inking it flatways, it is to make the &longs;eperation and | |
| <lb/>divi&longs;ion, and to &longs;o &longs;peak, an inci&longs;&longs;ion upon ten Feet of water; and | |
| <lb/>likewi&longs;e a le&longs;&longs;er Board that is four Feet in Perimeter, mu&longs;t make an | |
| <lb/>ince&longs;&longs;ion of four Feet. </s><s>This granted, he that hath any knowledge | |
| <lb/>in Geometry, will comprehend, not only that a Board &longs;awed in many | |
| <lb/>long thin pieces, will much better float than when it was entire, but | |
| <lb/>that all Figures, the more &longs;hort and narrow they be, &longs;hall &longs;o much the | |
| <lb/>better &longs;wim. </s><s>Let the Board ABCD be, for Example, eight | |
| <lb/>Palmes long, and five broad, its circuit &longs;hall be twenty &longs;ix Palmes; | |
| <lb/>and &longs;o many mu&longs;t the ince&longs;&longs;ion be, which it &longs;hall make in the water to | |
| <lb/>de&longs;cend therein: but if we do &longs;aw ir, as &longs;uppo&longs;e into eight little | |
| | |
| | |
| <pb pagenum="469"/>pieces, according to the Lines E F, G H, <emph type="italics"/>&c.<emph.end type="italics"/> making &longs;even Segments, | |
| <lb/>we mu&longs;t adde to the twenty &longs;ix Palmes of the circuit of the whole | |
| <lb/>Board, &longs;eventy others; whereupon the eight little pieces &longs;o cut and | |
| <lb/>&longs;eperated, have to cut ninty &longs;ix Palmes of water. </s><s>And, if moreover, | |
| <lb/>we cur each of the &longs;aid pieces into five parts, re­ | |
| <lb/><figure id="fig280"></figure> | |
| <lb/>ducing them into Squares, to the circuit of ninty | |
| <lb/>&longs;ix Palmes, with four cuts of eight Palmes apiece; | |
| <lb/>we &longs;hall adde al&longs;o &longs;ixty four Palmes, whereupon | |
| <lb/>the &longs;aid Squares to de&longs;cend in the water, mu&longs;t | |
| <lb/>divide one hundred and &longs;ixty Palmes of water, | |
| <lb/>but the Re&longs;i&longs;tance is much greater than that of | |
| <lb/>twenty &longs;ix; therefore to the le&longs;&longs;er Superficies, | |
| <lb/>we &longs;hall reduce them, &longs;o much the more ea&longs;ily | |
| <lb/>will they float: and the &longs;ame will happen in all | |
| <lb/>other Figures, who&longs;e Superficies are &longs;imular among&longs;t them&longs;elves, but | |
| <lb/>different in bigne&longs;s: becau&longs;e the &longs;aid Superficies, being either demini­ | |
| <lb/>&longs;hed or encrea&longs;ed, always dimini&longs;h or encrea&longs;e their Perimeters in | |
| <lb/>&longs;ubduple proportion; to wit, the Re&longs;i&longs;tance that they find in pene­ | |
| <lb/>trating the water; therefore the little pieces gradually &longs;wim, with more | |
| <lb/>and more facility as their breadth is le&longs;&longs;ened.</s></p><p type="main"> | |
| | |
| <s><emph type="italics"/>This is manife&longs;t; for keeping &longs;till the &longs;ame height of the Solid, with | |
| <lb/>the &longs;ame proportion as the Ba&longs;e encrea&longs;eth or demini&longs;heth, doth the &longs;aid | |
| <lb/>Solid al&longs;o encrea&longs;e or dimini&longs;h; whereupon the Solid more dimini&longs;hing | |
| <lb/>than the Circuit, the Cau&longs;e of Submer&longs;ion more dimini&longs;heth than the Cau&longs;e | |
| <lb/>of Natation: And on the contrary, the Solid more encrea&longs;ing than the | |
| <lb/>Circuit, the Cau&longs;e of Submer&longs;ion encrea&longs;eth more, that of Natation | |
| <lb/>le&longs;s.<emph.end type="italics"/></s></p><p type="main"> | |
| | |
| <s>And this may all be dedueed out of the Doctrine of <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> a­ | |
| <lb/>gain&longs;t his own Doctrine.</s></p><p type="main"> | |
| | |
| <s>La&longs;tly, to that which we read in the latter part of the Text, that | |
| <lb/><arrow.to.target n="marg1551"></arrow.to.target> | |
| <lb/>is to &longs;ay, that we mu&longs;t compare the Gravity of the Moveable with | |
| <lb/>the Re&longs;i&longs;tance of the Medium again&longs;t Divi&longs;ion, becau&longs;e if the force of | |
| <lb/>the Gravity exceed the Re&longs;i&longs;tance of the <emph type="italics"/>Medium,<emph.end type="italics"/> the Moveable will | |
| <lb/>de&longs;cend, if not it will float. </s><s>I need not make any other an&longs;wer, | |
| <lb/>but that which hath been already delivered; namely, that its not | |
| <lb/>the Re&longs;i&longs;tance of ab&longs;olute Divi&longs;ion, (which neither is in Water nor | |
| <lb/>Air) but the Gravity of the <emph type="italics"/>Medium<emph.end type="italics"/> that mu&longs;t be compared with the | |
| <lb/>Gravity of the Moveables; and if that of the <emph type="italics"/>Medium<emph.end type="italics"/> be greater, the | |
| <lb/>Moveable &longs;hall not de&longs;cend, nor &longs;o much as make a totall Submer&longs;ion, | |
| <lb/>but a partiall only: becau&longs;e in the place which it would occupy in | |
| <lb/>the water, there mu&longs;t not remain a Body that weighs le&longs;s than a like | |
| <lb/>quantity of water: but if the Moveable be more grave, it &longs;hall de&longs;­ | |
| <lb/>cend to the bottom, and po&longs;&longs;e&longs;s a place where it is more conformable | |
| | |
| <pb/> | |
| | |
| for it to remain, than another Body that is le&longs;s grave. </s><s>And this | |
| <lb/>is the only true proper and ab&longs;olute Cau&longs;e of Natation and Sub­ | |
| <lb/>mer&longs;ion, &longs;o that nothing el&longs;e hath part therein: and the Board of the | |
| <lb/>Adver&longs;aries &longs;wimmeth, when it is conjoyned with as much Air, | |
| <lb/>as, together with it, doth form a Body le&longs;s grave than &longs;o much water | |
| <lb/>as would fill the place that the &longs;aid Compound occupyes in the | |
| <lb/>water; but when they &longs;hall demit the &longs;imple Ebony into | |
| <lb/>the water, according to the Tenour of our Que­ | |
| <lb/>&longs;tion, it &longs;hall alwayes go to the bottom, | |
| <lb/>though it were as thin as a | |
| <lb/>Paper.</s></p><p type="margin"> | |
| | |
| <s><margin.target id="marg1551"></margin.target>Lib. 4. c. </s><s>6. | <s>Fir&longs;t, the weight <lb/>to be transferred from place to place; and &longs;econdly, the Force <lb/>and Power which &longs;hould move it; thirdly, the Di&longs;tance between <lb/>the one and the other Term of the Motion; Fourthly, the Time <lb/>in which that mutation is to be made: which Time becometh the <lb/>&longs;ame thing with the Dexterity, and Velocity of the Motion; we <lb/>determining that Motion to be more &longs;wift then another, which in <lb/>le&longs;&longs;e Time pa&longs;&longs;eth an equal Di&longs;tance.</s></p><p type="main"> |
| <lb/>Text 45.</s></p><p type="head"> | |
| | |
| <s><emph type="italics"/>FINIS.<emph.end type="italics"/></s></p> | <s>Now, any determinate Re&longs;i&longs;tance and limited Force what&longs;oever <lb/>being a&longs;&longs;igned, and any Di&longs;tance given, there is no doubt to be <lb/>made, but that the given Force may carry the given Weight to the <lb/>determinate Di&longs;tance; for, although the Force were extream <lb/>&longs;mall, yet, by dividing the Weight into many &longs;mall parts, none <lb/>of which remain &longs;uperiour to the Force, and by transferring them <lb/>one by one, it &longs;hall at la&longs;t have carried the whole Weight to the <lb/>a&longs;&longs;igned Term: and yet one cannot at the end of the Work with <lb/>Rea&longs;on &longs;ay, that that great Weight hath been moved, and tran&longs;­<lb/>ported by a Force le&longs;&longs;e then it &longs;elf, howbeit indeed it was done <lb/>by a Force, that many times reiterated that Motion, and that <lb/>Space, which &longs;hall have been mea&longs;ured but only once by the whole <lb/>Weight. </s> |
| | |
| | <s>From whence it appears, that the Velocity of the Force <lb/>hath been as many times Superiour to the Re&longs;i&longs;tance of the weight, <lb/>as the &longs;aid Weight was &longs;uperiour to the Force; for that in the <lb/>&longs;ame Time that the moving Force hath many times mea&longs;ured the <lb/>intervall between the Terms of the Motion, the &longs;aid Moveable <lb/>happens to have pa&longs;t it onely once: nor therefore ought we to <lb/>affirm a great Re&longs;i&longs;tance to have been overcome by a &longs;mall Force, <lb/>contrary to the con&longs;titution of Nature. </s> |
| | |
| | <s>Then onely may we &longs;ay <lb/>the Natural Con&longs;titution is overcome, when the le&longs;&longs;er Force tran&longs;­<lb/>fers the greater Re&longs;i&longs;tance, with a Velocity of Motion like to that <pb xlink:href="070/01/003.jpg" pagenum="273"/>wherewith it &longs;elf doth move; which we affirm ab&longs;olutely to be <lb/>impo&longs;&longs;ible to be done with any Machine imaginable. </s> |
| | |
| | <s>But becau&longs;e <lb/>it may &longs;ometimes come to pa&longs;&longs;e, that having but little Force, it is <lb/>required to move a great Weight all at once, without dividing it <lb/>in pieces, on this occa&longs;ion it will be necei&longs;ary to have recour&longs;e to <lb/>the Machine, by means whereof the propo&longs;ed Weight may be <lb/>transferred to the a&longs;&longs;igned Space by the Force given. </s> |
| | |
| | <s>But yet <lb/>this doth not hinder, but that the &longs;ame Force is to move, mea&longs;uring <lb/>that &longs;ame Space, or another equall to it, as many &longs;everall times as <lb/>it is exceeded by the &longs;aid Weight. </s> |
| | |
| | <s>So that in the end of the a­<lb/>ction we &longs;hall &longs;ind that we have received from the Machine no <lb/>other benefit tnen only that of tran&longs;porting the &longs;aid Weight with <lb/>the given Force to the Term given, all at once. </s> |
| | |
| | <s>Which Weight, <lb/>being divided into parts, would without any Machine have been <lb/>carried by the &longs;ame Force, in the &longs;ame Time, through the &longs;ame <lb/>Intervall. </s> |
| | |
| | <s>And this ought to pa&longs;&longs;e for one of the benefits taken <lb/>from the Mechanicks: for indeed it frequently happens, that be­<lb/>ing &longs;canted in Force but not Time, we are put upon moving great <lb/>Weights unitedly or in gro&longs;&longs;e: but he that &longs;hould hope, and at­<lb/>tempt to do the &longs;ame by the help of Machines without increa&longs;e of <lb/>Tardity in the Moveable, would certainly be deceived, and would <lb/>declare his ignorance of the u&longs;e of Mechanick In&longs;truments, and <lb/>the rea&longs;on of their effects.</s></p><p type="main"> |
| | |
| | <s>Another benefit is drawn from the In&longs;truments, which depend­<lb/>eth on the place wherein the operation is to be made: for all In­<lb/>&longs;truments cannot be made u&longs;e of in all places with equall conve­<lb/>nience. </s> |
| | |
| | <s>And &longs;o we &longs;ee (to explain our &longs;elves by an example) that <lb/>for drawing of Water out of a Well, we make u&longs;e of onely a <lb/>Rope and a Bucket fitted to receive and hold Water, wherewith <lb/>we draw up a determinate quantity of Water, in a certain Time, <lb/>with our limited &longs;trength: and he that &longs;hould think he could with <lb/>a Machine of what&longs;oever Force, with the &longs;ame &longs;trength, and in <lb/>the &longs;ame Time, take up a great quantity of Water, is in a gro&longs;&longs;e <lb/>Errour. </s> |
| | |
| | <s>And he &longs;hall find him&longs;elf &longs;o much the more deceived, <lb/>the more he &longs;hall vary and multiply his Inventions: Yet never­<lb/>thele&longs;&longs;e we &longs;ee Water drawn up with other Engines, as with a Pump <lb/>that drinks up Water in the Hold of Ships; where you mu&longs;t note <lb/>that the Pump was not imployed in tho&longs;e Offices, for that it draws <lb/>up more Water in the &longs;ame Time, and with the &longs;ame &longs;trength <lb/>then that which a bare Bucket would do, but becau&longs;e in that place <lb/>the u&longs;e of the Bucket or any &longs;uch like Ve&longs;&longs;el could not effect what <lb/>is de&longs;ired, namely to keep the Hold of the Ship quite dry from e­<lb/>very little quantity of Water; which the Bucket cannot do, for <lb/>that it cannot dimerge and dive, where there is not a con&longs;iderable <lb/>depth of Water. </s> |
| | |
| | <s>And thus we &longs;ee the Holds of Ships by the <pb xlink:href="070/01/004.jpg" pagenum="274"/>&longs;aid In&longs;trument kept dry, when Water cannot but onely oblique­<lb/>ly be drawn up, which the ordinary u&longs;e of the Bucket would not <lb/>effect, which ri&longs;eth and de&longs;cends with its Rope perpendicu­<lb/>larly.</s></p><p type="main"> |
| | |
| | <s>The third is a greater benefit, haply, then all the re&longs;t that are <lb/>derived from Mechanick In&longs;truments, and re&longs;pects the a&longs;&longs;i&longs;tance <lb/>which is borrowed of &longs;ome Force exanimate, as of the &longs;tream of a <lb/>River, or el&longs;e animate, but of le&longs;&longs;e expence by far, then that which <lb/>would be nece&longs;&longs;ary for maintaining humane &longs;trength: as when to <lb/>turn Mills, we make u&longs;e of the Current of a River, or the &longs;trength <lb/>of a Hor&longs;e, to effect that, which would require the &longs;trength of five <lb/>or fix Men. </s> |
| | |
| | <s>And this we may al&longs;o advantage our &longs;elves in rai&longs;ing <lb/>Water, or making other violent Motions, which mu&longs;t have been <lb/>done by Men, if there were no other helps; becau&longs;e with one &longs;ole <lb/>Ve&longs;&longs;el we may take Water, and rai&longs;e, and empty it where occa&longs;ion <lb/>requires; but becau&longs;e the Hor&longs;e, or &longs;uch other Mover wanteth <lb/>Rea&longs;on, and tho&longs;e In&longs;truments which are requi&longs;ite for holding and <lb/>emptying the Ve&longs;&longs;el in due time, returning again to fill it, and one­<lb/>ly is endued with Force, therefore it's nece&longs;&longs;ary that the Mecha­<lb/>nitian &longs;upply the naturall defect of that Mover, furni&longs;hing it with <lb/>&longs;uch devices and inventions, that with the &longs;ole application of it's <lb/>Force the defired effect may follow. </s> |
| | |
| | <s>And therein is very great <lb/>advantage, not becau&longs;e that a Wheel or other Machine can enable <lb/>one to tran&longs;port the &longs;ame Weight with le&longs;&longs;e Force, and greater <lb/>Dexterity, or a greater Space than an equall Force, without tho&longs;e <lb/>In&longs;truments, but having Judgment and proper Organs, could have <lb/>done; but becau&longs;e that the &longs;tream of a River co&longs;teth little or <lb/>nothing, and the charge of keeping of an Hor&longs;e or other Bea&longs;t, <lb/>who&longs;e &longs;trength is greater then that of eight, or it may be more <lb/>Men, is far le&longs;&longs;e then what &longs;o many Men would be kept <lb/>for.</s></p><p type="main"> |
| | |
| | <s>The&longs;e then are the benefits that may be derived from Mecha­<lb/>nick In&longs;truments, and not tho&longs;e which ignorant Engineers dream <lb/>of, to their own di&longs;grace, and the abu&longs;e of &longs;o many Princes, <lb/>whil&longs;t they undertake impo&longs;&longs;ible enterprizes; of which, both <lb/>by the little which hath been hinted, and by the much which <lb/>&longs;hall be demon&longs;trated in the Progre&longs;&longs;e of this Treati&longs;e, we &longs;hall <lb/>come to a&longs;&longs;ure our &longs;elves, if we attentively heed that which &longs;hall <lb/>be &longs;poken.</s></p><pb xlink:href="070/01/005.jpg" pagenum="275"/><p type="head"> |
| | |
| | <s>DEFINITIONS.</s></p><p type="main"> |
| | |
| | <s>That which in all Demon&longs;trative Sciences is nece&longs;&longs;ary to be <lb/>ob&longs;erved, we ought al&longs;o to follow in this Di&longs;cour&longs;e, that is; <lb/>to propound the Definitions of the proper Terms of this <lb/>Art, and the primary Suppo&longs;itions, from which, as from &longs;eeds full <lb/>of fecundity, may of con&longs;equence &longs;pring and re&longs;ult the cau&longs;es, <lb/>and true Demon&longs;trations, of the Nature of all the Mechanick <lb/>Engines which are u&longs;ed, for the mo&longs;t part about the Motions of <lb/>Grave Matters, therefore we will determine, fir&longs;t, what is <emph type="italics"/>GRA­<lb/>VITIE.<emph.end type="italics"/></s></p><p type="main"> |
| | |
| | <s>We call <emph type="italics"/>GRAVITIE<emph.end type="italics"/> then, That propen&longs;ion of moving <lb/>naturally downwards, which is found in &longs;olid Bodies, cau&longs;ed by <lb/>the greater or le&longs;&longs;e quantity of matter, whereof they are con&longs;ti­<lb/>tuted.</s></p><p type="main"> |
| | |
| | <s><emph type="italics"/>MOMENT<emph.end type="italics"/> is the propen&longs;ion of de&longs;cending, cau&longs;ed not &longs;o <lb/>much by the Gravity of the moveable, as by the di&longs;po&longs;ure which <lb/>divers Grave Bodies have in relation to one another; by means of <lb/>whichMoment, we oft &longs;ee a Body le&longs;s Grave counterpoi&longs;e another <lb/>of greater Gravity: as in the Stiliard, a great Weight is rai&longs;ed by <lb/>a very &longs;mall counterpoi&longs;e, not through exce&longs;s of Gravity, but <lb/>through the remotene&longs;&longs;e from the point whereby the Beam is up­<lb/>held, which conjoyned to the Gravity of the le&longs;&longs;er weight adds <lb/>thereunto Moment, and <emph type="italics"/>Impetus<emph.end type="italics"/> of de&longs;cending, wherewith the <lb/>Moment of the other greater Gravity may be exceeded. <emph type="italics"/>MO­<lb/>MENT<emph.end type="italics"/> then is that IMPETUS of de&longs;cending, compounded <lb/>of Gravity, Po&longs;ition, and the like, whereby that propenfion may <lb/>be occa&longs;ioned</s></p><p type="main"> |
| | |
| | <s>The <emph type="italics"/>CENTER<emph.end type="italics"/> of <emph type="italics"/>GRAVITY<emph.end type="italics"/> we define to be that point <lb/>in every Grave Body, about which con&longs;i&longs;t parts of equall Moment: <lb/>&longs;o that, imagining &longs;ome Grave Body to be &longs;u&longs;pended and &longs;u&longs;tain­<lb/>ed by the &longs;aid point, the parts on the right hand will Equilibrate <lb/>tho&longs;e on the left, the Anteriour, the Po&longs;teriour, and tho&longs;e above <lb/>tho&longs;e below; &longs;o that be it in any what&longs;oever fite, and po&longs;ition, <lb/>provided it be &longs;u&longs;pended by the &longs;aid <emph type="italics"/>CENTER,<emph.end type="italics"/> it &longs;hall &longs;tand <lb/>&longs;till: and this is that point which would gladly unite with the <lb/>univer&longs;all Center of Grave Bodies, namely withthat of the Earth, <lb/>if it might thorow &longs;ome free <emph type="italics"/>Medium<emph.end type="italics"/> de&longs;cend thither. </s> |
| | |
| | <s>From <lb/>whence we take the&longs;e Suppo&longs;itions.</s></p><pb xlink:href="070/01/006.jpg" pagenum="276"/><p type="head"> |
| | |
| | <s>SUPPOSITIONS.</s></p><p type="main"> |
| | |
| | <s>Any Grave Body, (as to what belongeth to it's proper ver­<lb/>tue) moveth downwards, &longs;o that the Center of it's Gravity <lb/>never &longs;trayeth out of that Right Line which is produced <lb/>from the &longs;aid Center placed in the fir&longs;t Term of the Motion unto <lb/>the univer&longs;al Center of Grave Bodies. </s> |
| | |
| | <s>Which is a Suppo&longs;ition <lb/>very manife&longs;t, becau&longs;e that &longs;ingle Center being obliged to endea­<lb/>vour to unite with the common Center, it's nece&longs;&longs;ary, unle&longs;&longs;e &longs;ome <lb/>impediment intervene, that it go &longs;eeking it by the &longs;horte&longs;t Line, <lb/>which is the Right alone: And from hence may we &longs;econdarily <lb/>&longs;uppo&longs;e</s></p><p type="main"> |
| | |
| | <s>Every Grave Body putteth the greate&longs;t &longs;tre&longs;&longs;e, and weigheth <lb/>mo&longs;t on the Center of it's Gravity, and to it, as to its proper &longs;eat, <lb/>all <emph type="italics"/>Impetus,<emph.end type="italics"/> all Pondero&longs;ity, and, in &longs;ome, all Moment hath re­<lb/>cour&longs;e.</s></p><p type="main"> |
| | |
| | <s>We la&longs;tly &longs;uppo&longs;e the Center of the Gravity of two Bodies e­<lb/>qually Grave to be in the mid&longs;t of that Right Line which conjoyns <lb/>the &longs;aid two Centers; or that two equall weights, &longs;u&longs;pended in <lb/>equall di&longs;tence, &longs;hall have the point of <emph type="italics"/>Equilibrium<emph.end type="italics"/> in the common <lb/>Center, or meeting of tho&longs;e equal Di&longs;tances. </s> |
| | |
| | <s>As for Example, <lb/>the Di&longs;tance C E being equall to the Di&longs;tance E D, and there be­<lb/>ing by them two equall weights &longs;u&longs;pended, A and B, we &longs;uppo&longs;e <lb/>the point of <emph type="italics"/>Equilibrium<emph.end type="italics"/> to be in the point E, there being no <lb/>greater rea&longs;on for inclining to <lb/>one, then to the other part. </s> |
| | |
| | <s>But <lb/><figure id="id.070.01.006.1.jpg" xlink:href="070/01/006/1.jpg"/><lb/>here is to be noted, that the Di­<lb/>&longs;tances ought to be mea&longs;ured <lb/>with Perpendicular Lines, which <lb/>from the point of Su&longs;pen&longs;ion E, <lb/>fall on the Right Lines, that from <lb/>the Center of the Gravity of the <lb/>Weights A and B, are drawn to <lb/>the common Center of things <lb/>Grave; and therefore if the Di&longs;tance E D were tran&longs;ported into <lb/>E F, the weight B would not counterpoi&longs;e the weight A, becau&longs;e <lb/>drawing from the Centers of Gravity two Right Lines to the Cen­<lb/>ter of the Earth, we &longs;hall &longs;ee that which cometh from the Center <lb/>of the Weight I, to be nearer to the Center E, then the other <lb/>produced from the Center of the weight A. </s> |
| | |
| | <s>Therefore our &longs;aying <lb/>that equal Weights are &longs;u&longs;pended by [or at] equal Di&longs;tances, is <lb/>to be under&longs;tood to be meant when as the Right Lines that go from <lb/>their Centers & to &longs;eek out the common Center of Gravity, &longs;hall be <lb/>equidi&longs;ta nt from that Right Line, which is produced from the &longs;aid <pb xlink:href="070/01/007.jpg" pagenum="277"/>Term of tho&longs;e Di&longs;tances, that is from the point of Su&longs;pen&longs;ion, to <lb/>the &longs;ame Center of the Earrh.</s></p><p type="main"> |
| | |
| | <s>The&longs;e things determined and &longs;uppo&longs;ed, we come to the explica­<lb/>tion of a Principle, the mo&longs;t common and materiall of the greater <lb/>part of Mechanick In&longs;truments: demon&longs;trating, that unequall <lb/>Weights weigh equally when &longs;u&longs;pended by [or at] unequal Di&longs;tan­<lb/>ces, which have contrary proportion to that which tho&longs;e weights <lb/>are found to have, See the Demon&longs;tration in the beginning of the <lb/>&longs;econd Dialogue of Local-Motions.</s></p><p type="head"> |
| | |
| | <s><emph type="italics"/>Some Adverii&longs;ements about what hath been &longs;aid.<emph.end type="italics"/></s></p><p type="main"> |
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| | <s>Now being that Weights unequall come to acquire equall <lb/>Moment, by being alternately &longs;u&longs;pended at Di&longs;tances that <lb/>have the &longs;ame proportion with them; I think it not fit to <lb/>over pa&longs;&longs;e with &longs;ilence another congruicy and probability, which <lb/>may confirm the &longs;ame truth; for let the Ballance A B, be con&longs;ide­<lb/>red, as it is divided into unequal parts in the point C, and let the <lb/>Weights be of the &longs;ame propor­<lb/><figure id="id.070.01.007.1.jpg" xlink:href="070/01/007/1.jpg"/><lb/>tion that is between the Di&longs;tan­<lb/>ces B C, and C A, alternately <lb/>&longs;u&longs;pended by the points A, and <lb/>B: It is already manife&longs;t, that <lb/>the one will counterpoi&longs;e the <lb/>other, and con&longs;equently, that <lb/>were there added to one of them <lb/>a very &longs;mall Moment of Gravity, it would preponderate, rai&longs;ing <lb/>the other, &longs;o that an in&longs;en&longs;ible Weight put to the Grave B, the <lb/>Ballance would move and de&longs;cend from the point B towards E, <lb/>and the other extream A would a&longs;cend into D, and in regard that <lb/>to weigh down B, every &longs;mall Gravity is &longs;ufficient, therefore not <lb/>keeping any accompt of this in&longs;en&longs;ible Moment, we will put no <lb/>difference between one Weights <emph type="italics"/>&longs;u&longs;taining,<emph.end type="italics"/> and one Weights <lb/><emph type="italics"/>moving<emph.end type="italics"/> another. </s> |
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| | <s>Now, let us con&longs;ider the Motion which the <lb/>Weight B makes, de&longs;cending into E, and that which the other <lb/>A makes in a&longs;cending into D, we &longs;hall without doubt find the <lb/>Space B E to be &longs;o much greater than the Space A D, as the Di­<lb/>&longs;tance B C is greater than C A, forming in the Center C two an­<lb/>gles D C A, and E C B, equall as being at the Cock, and con&longs;e­<lb/>quently two Circumferences A D and B E alike; and to have the <lb/>&longs;ame proportion to one another, as have the Semidiameters B C, <lb/>and C A, by which they are de&longs;cribed: &longs;o that then the Velocity <lb/>of the Motion of the de&longs;cending Grave B cometh to be &longs;o much <lb/>Superiour to the Velocity of the other a&longs;cending Moveable A, as <lb/>the Gravity of this exceeds the Gravity of that; and it not being <pb xlink:href="070/01/008.jpg" pagenum="278"/>po&longs;&longs;ible that the Weight A &longs;hould be rai&longs;ed to D, although &longs;low­<lb/>ly, unle&longs;&longs;e the other Weight B do move to E &longs;wiftly, it will not <lb/>be &longs;trange, or incon&longs;i&longs;tent with the Order of Nature, that the <lb/>Velocity of the Motion of the Grave B, do compen&longs;ate the greater <lb/>Re&longs;i&longs;tance of the Weight A, &longs;o long as it moveth &longs;lowly to D, <lb/>and the other de&longs;cendeth &longs;wiftly to E, and &longs;o on the contrary, <lb/>the Weight A being placed in the point D, and the other B in <lb/>the point E, it will not be unrea&longs;onable that that falling lea&longs;urely <lb/>to A, &longs;hould be able to rai&longs;e the other ha&longs;tily to B, recovering by <lb/>its Gravity what it had lo&longs;t by it's Tardity of Motion. </s> |
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| | <s>And by <lb/>this Di&longs;cour&longs;e we may come to know how the Velocity of the <lb/>Motion is able to encrea&longs;e Moment in the Moveable, according to <lb/>that &longs;ame proportion by which the &longs;aid Velocity of the Motion is <lb/>augmented.</s></p><p type="main"> |
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| | <s>There is al&longs;o another thing, before we proceed any farther, to <lb/>be confidered; and this is touching the Di&longs;tances, whereat, or <lb/>wherein Weights do hang: for it much imports how we are to <lb/>under&longs;tand Di&longs;tances equall, and unequall; and, in &longs;um, in what <lb/>manner they ought to be mea­<lb/><figure id="id.070.01.008.1.jpg" xlink:href="070/01/008/1.jpg"/><lb/>&longs;ured: for that A B being the <lb/>Right Line, and two equall <lb/>Weights being &longs;u&longs;pended at <lb/>the very ends thereof, the point <lb/>C being taken in the mid&longs;t of <lb/>the &longs;aid Line, there &longs;hall be an <lb/><emph type="italics"/>Equilibrium<emph.end type="italics"/> upon the &longs;ame: <lb/>And the rea&longs;on is for that the <lb/>Di&longs;tance C B is equal to C A. <lb/></s> |
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| | <s>But if elevating the Line C B, moving it about the point C, it <lb/>&longs;hall be transferred into CD, &longs;o that the Ballance &longs;tand according <lb/>to the two Lines A C, and C D, the two equall Weights hanging <lb/>at the Terms A and D, &longs;hall no longer weigh equally on that <lb/>point C, becau&longs;e the di&longs;tance of the Weight placed in D, is made <lb/>le&longs;&longs;e then it was when it hanged in B. </s> |
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| | <s>For if we confider the Lines, <lb/>along [or by] which the &longs;aid Graves make their Impul&longs;e, and <lb/>would de&longs;cend, in ca&longs;e they were freely moved, there is no doubt <lb/>but that they would make or de&longs;cribe the Lines A G, D F, B H: <lb/>Therefore the Weight hanging on the point D, maketh it's Moment <lb/>and <emph type="italics"/>Impetus<emph.end type="italics"/> according to the Line D F: but when it hanged in <lb/>B, it made <emph type="italics"/>Impetus<emph.end type="italics"/> in the Line B H: and becau&longs;e the Line D F is <lb/>nearer to the Fulciment C, then is the Line B H Therefore we <lb/>are to under&longs;tand that the Weights hanging on the points A and D, <lb/>are not equi-di&longs;tant from the point C, as they be when they are <lb/>con&longs;tituted according to their Right Line A C B: And la&longs;tly, <lb/>we are to take notice, that the Di&longs;tance is to be mea&longs;ured by <pb xlink:href="070/01/009.jpg" pagenum="279"/>Lines, which fall at Right Angles on tho&longs;e whereon the Weights <lb/>hang, and would move, if &longs;o be they were permitted to de&longs;cend <lb/>freely.</s></p><p type="head"> |
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| | <s>Of the BALLANCE and LEAVER.</s></p><p type="main"> |
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| | <s>Having under&longs;tood by certain Demon&longs;tration, one of the <lb/>fir&longs;t Principles, from which, as from a plenti&longs;ul Fountain, <lb/>many of the Mechanical In&longs;truments are derived, we may <lb/>take occa&longs;ion without any difficulty to come to the knowledge of <lb/>the nature of them: and fir&longs;t &longs;peaking of the Stiliard, an In&longs;tru­<lb/>ment of mo&longs;t ordinary u&longs;e, with which divers Merchandizes are <lb/>weighed, &longs;u&longs;taining them, though very heavy, with a very &longs;mall <lb/>counterpoi&longs;e, which is com­<lb/>monly called the Roman or <lb/><figure id="id.070.01.009.1.jpg" xlink:href="070/01/009/1.jpg"/><lb/>Plummet, we &longs;hall prove that <lb/>there is no more to be done in <lb/>&longs;uch an operation, but to re­<lb/>duce into act and practice <lb/>what hath been above contemplated. </s> |
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| | <s>For if we propo&longs;e the Bal­<lb/>lance A B, who&longs;e Fulciment or Lanquet is in the point C, by <lb/>which, at the &longs;mall Di&longs;tance C A, hangeth the heavy Weight D, <lb/>and if along the other greater C B, (which we call the Needle of <lb/>the Stiliard) we &longs;hould &longs;uppo&longs;e the Roman F, though of but little <lb/>weight in compari&longs;on of the Grave Body D to be &longs;lipped to and <lb/>fro, it &longs;hall be pof&longs;ible to place it &longs;o remotely from the Lanquet C, <lb/>that the &longs;ame proportion may be found between the two Weights <lb/>D and F, as is between the Di&longs;tances F C, and C A: and then &longs;hall <lb/>an <emph type="italics"/>Equilibrium<emph.end type="italics"/> &longs;ucceed; unequall Weights hanging at Di&longs;tances <lb/>alternately proportional to them.</s></p><p type="main"> |
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| | <s>Nor is this In&longs;trument different from that other called <emph type="italics"/>Vectis,<emph.end type="italics"/><lb/><arrow.to.target n="marg1107"></arrow.to.target><lb/>and vulgarly the ^{*} Leaver, wherewith great Weights are moved <lb/>by &longs;mall Force; the application of which is according to the Fi­<lb/>gure prefixed; wherein the Leaver <lb/>is repre&longs;ented by the Bar of wood <lb/>or other &longs;olid matter, <emph type="italics"/>B<emph.end type="italics"/> C D, let <lb/><figure id="id.070.01.009.2.jpg" xlink:href="070/01/009/2.jpg"/><lb/>the heavy Weight to be rai&longs;ed be <lb/>A, and let the &longs;teadfa&longs;t &longs;upport <lb/>or Fulciment on which the Leaver <lb/>re&longs;ts and moves be &longs;uppo&longs;ed to be <lb/>E, and putting one end of the <lb/>Leaver under the Weight A, as <lb/>may be &longs;een in the point C, en­<lb/>crea&longs;ing the Weight or Force at the other end D, it will be able <lb/>to lift up the Weight A, though not much, whenever the Force in <pb xlink:href="070/01/010.jpg" pagenum="280"/>D hath the &longs;ame proportion to the Re&longs;i&longs;tance made by the Weight <lb/>A, in the point C: as the Di&longs;tance <emph type="italics"/>B<emph.end type="italics"/> C hath to the Di&longs;tance C D, <lb/>whereby it's clear, that the nearer the Fulciment E &longs;hall approach <lb/>to the Term B, encrea&longs;ing the proportion of the Di&longs;tance D C to <lb/>the Di&longs;tance C <emph type="italics"/>B,<emph.end type="italics"/> the more may one dimini& |