Borelli, Giovanni Alfonso De motionibus naturalibus a gravitate pendentibus 1670 Reggio di Calabria la borel_demot_010_la_1670.xml 010.xml

DE MOTIONIBVS NATVRALIBVS A GRAVITATE PENDENTIBVS

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DE MOTIONIBVS NATVRALIBVS A GRAVITATE PENDENTIBVS, LIBER IO: ALPHONSI BORRELLI in Academia Pi&longs;ana Mathe&longs;eos profe&longs;&longs;oris.

REGIO IVLIO, In Officina Dominici Ferri. 1670.

Superiorum permi&longs;&longs;u.

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ILLVSTRISS. ET EXCELLENTISS. DOMINO D. ANDREÆ CONCVBLET MARCHIONI ARENÆ. IO: ALPHONSVS BORRELLVS. S.

SI quid præclara nobilitas laudis, & commendationis mere­tur, id profectò non filijs &longs;ed progenitoribus tribuendum e&longs;&longs;e Sapientes non nulli cen&longs;uere; proinde qui nobilitatem iactat, de­cus, ac bonum alienum non &longs;uum commendare dixerunt. Hoc &longs;a­nè verum e&longs;&longs;et, &longs;i Parentes alienæ, & minimè naturales e&longs;­&longs;ent liberorum cau&longs;æ, neque materiam, aut influxum in genera­tione præ&longs;tarent: at &longs;ecus res &longs;e habet, &longs;icut enim plantarum ger­mina, & fructus ip&longs;is Arboribus, ac Seminibus conformes e&longs;&longs;&etail;, nec vnquam Ro&longs;am è papactere, aut dulcia Poma ex Quercu pro-

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PROOEMIVM AD LECTOREM.

HAbesiam, erudite Lector, in hoc Libro de Motionibus Natura­libus à grauitate pendentibus, vna cum præcedenti do Vi Per­cn&longs;&longs;ionis ea omnia, quæ præmitti debuerant ad perfectam intelligen­tiam doctrinæ de animalium motibus, exceptis quamplurimis mecha­nicis lemmatibus, quæ &longs;uis locis deincepsiuxta &longs;ubiecti exigentia&mtail; exponentur. Debeo tamen nonnulla præfari de hoc, & præcedenti Opere, in quibus multoties afferuntur &longs;ententiæ diuer&longs;æ ab Authorum magni nominis opinionibus. Hoc tamen &longs;umma mode&longs;tia, & modera­tione exequutus &longs;um; quandoquidem &longs;ententias in&longs;ector, non autem authorum nomina, aut famam attingo: quippe qui &longs;olummodo veri­tatem quæro, &longs;eruata interim dignitate, & fama clari&longs;&longs;imorum viro­rum: quod con&longs;tat ex eo, quod tunc &longs;olummodo viuentium autho­rum nomina recen&longs;eo, cum laudandi eos occa&longs;io offertur; cum vero controuer&longs;iæ agitantur nomina authorum omnino teguntur, ac &longs;ilen­tur; quia verò hac tan religio&longs;a mederatione, & mode&longs;tia effugere non potui contradicentium mordacitates, ideo vi&longs;um e&longs;t denuo pollicer&etail; me ab in&longs;tituto incepto non dimoueri, nec di&longs;cedere velle, neque op­po&longs;it oribus, &longs;i qui for&longs;an extiterint, re&longs;pon&longs;um vllum apologeticum, & contentio&longs;um edere velle, &longs;ed tantummodo &longs;i opus fuerit meam do­ctrinam melius, & apertius declarare, vel corrigere vbi for&longs;an huma­no more lap&longs;us fuero. Vale.

DE MOTIONIBVS NATVRALIBVS A Grauitate pendentibus.

LIBER

IO: ALPHONSI BORELLI

Motus Corporum &longs;ublunarium in medio fluido fieri, de quibus hactenus nemo tract auit.

CAPVT I.

EVidenti&longs;&longs;imum e&longs;t motus corporum &longs;ub­lunarium fieri debere in aliquo &longs;patio, quod minimè impleri & occupari de­bet à corporibus duris, con&longs;i&longs;tentibus, & omninò continuis, propterea quòd duo corpora &longs;e mutuò penetrare nequeunt, igitur nece&longs;&longs;e e&longs;t vt &longs;patium, in quo corpus aliquod moue­ri debet, aut &longs;it omninò vacuum, vel &longs;altem occupe­tur ab aliquo corpore di&longs;trahibili, & fluido, vel in particulas &longs;ubdiui&longs;o, quod nimirum facilè expelli po&longs;&longs;it è &longs;uo loco, vt &longs;ubintranti corpori, quod moue­ri debet locum cedat. ab hi&longs;ce fluidis corporibus re­gio i&longs;ta terram ambiens occupatur, vt ab aqua, aere, & igne, in quibus fiunt motiones corporum &longs;ublu­narium.

De ip&longs;is porrò naturalibus motionibus corporum, qu&ecedil; in medio fluido fiunt, &longs;cilicèt qua ratione, & qua-

re corpora varias magnitudines, pondera, & di­uer&longs;as figuras habentia, moueantur maiori, aut mi­nori velocìmte, certa quadam proportione in medio fluido, nemo (quodl&longs;ciam) differuit. Igitur hanc phy&longs;ico-mechanices partem hactenùs de&longs;iderata&mtail; exponere, ac &longs;upplere animus e&longs;t; &longs;ed ne fa&longs;tidio&longs;&atail; repetitione earum rerum, quæ ab alijs tradita &longs;unt, lectores de tineam, &longs;upponam ea omnia, quæ in ele­mentis mechanicis tradita &longs;unt de natura libræ, vec­tis, trochleæ, & de reliquis ab hi&longs;ce in&longs;trumentis pen­dentibus, eorum que naturam participantibus. afferam tantummodò aliqua quæ præcipuum v&longs;um habent in hac doctrina de naturalibus corporum motionibus, non de omnibus, &longs;ed de ijs &longs;olum modò, quæ à vi mo­tiua grauitatis pendent.

Cap. 1. Cor­porum mo­tus in medio fluido fieri.

De Momentis Grauium con&longs;istentium & fluidorum in ij&longs;dem fluidis innatantium.

CAP. II.

SVbtili&longs;&longs;imè, & præclarè Archimedes egit de in&longs;i­dentibus humido, idip&longs;um po&longs;te a alia methodo Galileus, & Steuinus demon&longs;tiatunt, cùm veritas in­numeris modis confirmari po&longs;&longs;it, ip&longs;e verò, non ge­nio variandi, nouas earumdem propo&longs;itionum de­mon&longs;trationes via longè diuer&longs;a procedendo, exco­gitaui, & attnli, &longs;ed quia hæ valdè conducunt ad ea quæ po&longs;terius à nobis expliconda &longs;unt. at priùs ali­quæ hypothe&longs;es &longs;unt præmittendæ.

Cap. 1. de momentis grauium in fluido inna­tantium.

SVPPOSITIO I.

Suppono primò quòd quodlibet corpus, &longs;iuè den­&longs;um, &longs;iuè fluidum, ex ijs quæ globum terra-queu&mtail; componunt, graue e&longs;t, exercetque vim &longs;eù conatum fuæ grauitatis, etiam &longs;i in fluido &longs;ibi aut homogeneo, aut non, con&longs;tituatur. hoc autem &longs;uo loco euidenti&longs;­&longs;imis rationibus, ac experimentis confirmabitur.

SVPPOSITIO II.

Secundo loco &longs;uppono vim, &longs;eù conatum, quo &longs;lui­da nituntur &longs;e&longs;e vnire &longs;phæræ terra queæ, effici per lineas perpendiculares ad &longs;uperficiem horizontis. & hoc patet quia quodlibet graue naturali in&longs;tinctuco­natur ad centrum terræ accedere via breui&longs;&longs;ima, igi­tur directio prædictimotus, &longs;eù conatus compre&longs;&longs;iuus efficietur per &longs;emidiametros eiu&longs;dem terræ, hæ verò perpendiculares &longs;unt ad &longs;uperficiem horizontalem, quæ &longs;phæricè ip&longs;amterram comprehendit, igitur ma­nife&longs;tum e&longs;t quòd motus &longs;eù conatus compre&longs;&longs;iuus omnium partium fluidi per lineas ad horizontem per­pendiculares efficitur.

SVPPOSITIO III.

Tertiò quod libet corpus graue e&longs;t impo&longs;&longs;ibile vt moueatur motu &longs;pontaneo, & naturali, quando ad cen­trum telluris minimè approximari pote&longs;t. hoc mani­fe&longs;tum e&longs;t quia cùm omnes partes terrenæ vt graues naturali in&longs;tinctu ad terræ centrum accedere conen-tur, hocque earum de&longs;iderium expleri minimè po&longs;&longs;it ni&longs;i mediante motu, igitur ce&longs;&longs;ante fine nece&longs;&longs;ariò medium quoque ce&longs;&longs;at, &longs;cilicet quando non pote&longs;t graue aliquod magis, quàm prius ad terræ centrum accedere, tunc nequa quam moue bitur. ex quo &longs;equi­tur vt prædicta corpora quie&longs;cant, quandoquidem &longs;i mouerentur, aut deberent à centro telluris recedere & remoueri, vel lateraliter circumferri, in primo ca­&longs;u &longs;equeretur operatio contraria naturali in&longs;tinctui grauium, quod e&longs;t impo&longs;&longs;ibile; in &longs;ecundo verò ca&longs;u efficeretur operatio vanæ, & &longs;i fru&longs;tratoria, nil enim graue præterea acquireret cùm non amplius ad terræ centru accedere po&longs;&longs;et ex hypothe&longs;i, ab&longs;urdum verò e&longs;t atque repugnat naturam operari ca&longs;n, & ab&longs;que fine; igitur e&longs;t impo&longs;&longs;ibile vt corpora, quæ ad centrum terræ accedere nequeunt, vllo pacto moueantur; qua propter nece&longs;&longs;e e&longs;t vt in eodem &longs;itu fixè quie&longs;cant in quo prius degebant.

Cap. 2. de momentis grauium in fluido inna­tantium.

SVPPOSITIO IV.

Archimedis &longs;suppositio.

Præterea Archimedes &longs;uppo&longs;uit vt primum prin­cipium per &longs;e notum, quod eiu&longs;dem fluidi con&longs;i&longs;ten­tis, partes quæ &longs;int continuat&ecedil; in eodem plano hori­zontaliminus pre&longs;&longs;æ debeant eijci expellique &longs;ur&longs;um perpendiculariter à partibus eiu&longs;dem fluidi magis com­pre&longs;&longs;is, hoc verò principium, licèt veri&longs;&longs;imum &longs;it, ha­bet tamen aliquam ob&longs;curitatem, cùm minimè eui­dens &longs;it, quamobrem partes eiu&longs;dem fluidi po&longs;&longs;int magis, aut minus comprimi; nec pariter euidenter

percipitur quomodo à naturali operatione, de&longs;cen­&longs;us nempè deor&longs;um, produci debeat operatio quædam contraria, a&longs;cen&longs;us nimirum alterius partis eiu&longs;dem fluidi &longs;cilicet recedendo a centro telluris. erit igitur operæpretium perfpicuè o&longs;tendere veritatem præ­dictæ operationis, eamque deducere ex principijs magis notis, & euidentibus.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium.

PROPOSITIO I.

Grauis &longs;u&longs;pen&longs;i non ex centro &longs;uæ grauitatis vna eius pærs &longs;ur&longs;um a&longs;cendit quiæ integrum graue deorsum de&longs;cendit.

SIt graue AB exten&longs;um, vel compo&longs;itum ex dua­bus partibus in extremitatibus eiu&longs;dem libræ horizontalis AB di&longs;po&longs;itis, & commune centrum gra­uitatis earum &longs;it D. &longs;u&longs;ti­

neatur po&longs;tea, fulciatur­que tota libra ex puncto C remoto à centro graui­tatis D. dico quòd pars eius oppo&longs;ita B &longs;ur&longs;u&mtail; a&longs;cendet per arcum BF, hac &longs;olummodo de cau&longs;&atail; quia integrum graue AB magis, quàm prius ad cen­trum terræ accedit. quia duæ partes graues A & B exercent &longs;uam grauitatem & conatum compre&longs;&longs;iuum in centro communi earum grauitatum D; e&longs;t que prædictum centrum D remotum à fulcimento &longs;tabili C, igitur efformabitur veluti fune-pendulum CD horizontaliter con&longs;titutum, &longs;u&longs;pen&longs;um, & alligatum in centro C & pondus vniuer&longs;um applicatum eriti&ntail; centro D extremo fili, vel lineæ CD: &longs;ed penduli na­tura talis e&longs;t vt conetur deor&longs;um ferri per arcum qua­drantis DE circa centrum eius &longs;ixum C v&longs;que ad lo­cum infimum E, quod magis ad centrum terræ appro­ximatur, quàm in &longs;itu horizontali D & patet quòd vniuer&longs;a hæcoperatio nece&longs;&longs;aria, & naturalis e&longs;t de­pendens à de&longs;cen&longs;u totius grauis. & e&longs;t impo&longs;&longs;ibil&etail; vt fune pendulum CD ad in fimum &longs;itum CE perduca­tur ab&longs;que eo quòd libra rigida &longs;itum perpendicula­rem ad horizontem acquirat, quale e&longs;t GCF, hoc ve­ro minimè acquiri pote&longs;t ni&longs;i pars minus grauis libræ B &longs;ur&longs;um a&longs;cendat per arcum BF, igitur ca&longs;us, & de­&longs;cen&longs;us totius corporis grauis AB à &longs;itu eleuato D ad infimum E e&longs;t vera & legitima cau&longs;a a&longs;cen&longs;us corpo­ris grauis B per arcum BF, quod fuerat o&longs;tendendum.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

Patet igitur quod &longs;im­plex ca&longs;us, aut de&longs;cen&longs;us corporis grauis e&longs;t vera, & legitima cau&longs;a motus, & a&longs;cen&longs;us alicuius partis eius &longs;ur&longs;um, & hoc planè contingit quotie&longs;cumque graue vniuer&longs;um &longs;u&longs;tine­tur ab aliquo eius puncto libræ realis, vel imagina­riæ, itaut efficiatur commotio omnium partium eius non quidem per lineas rectas inter &longs;e parallelas, & horizonti perpendiculares, &longs;ed vertigino&longs;as, & cir-culares quales &longs;unt illæ quæ à fune-pendulis de&longs;cri­buntur, & in prædicto motu vertigino&longs;o e&longs;t tam ne­ce&longs;&longs;arius, & naturalis a&longs;cen&longs;us partis minus grauis B per arcum BF quemadmodum nece&longs;&longs;arius e&longs;t lap&longs;us & de&longs;cen&longs;us totius grauis per arcum DE v&longs;que ad lo­cum infimum E & licet a&longs;cen&longs;us prædictæ portionis B vulgo cen&longs;eatur motus violentus, nihilominus &longs;i perpendatur vertigo, & debita &longs;ituatio corporis gra­uis quatenus naturalis e&longs;t & naturali in&longs;tinctu acqui­&longs;ita, & producta; cùm &longs;it impo&longs;&longs;ibile vt prædicta &longs;itua­tio debita ab&longs;olute con&longs;equatur ab&longs;que a&longs;cen&longs;u por­tionis B &longs;itque verum quoque quod, qui vult fine&mtail; velit quoque nece&longs;&longs;e e&longs;t media, quæ ad finem con&longs;e­quendum nece&longs;&longs;aria sunt; hinc rationabiliter inferetur à vi naturali verè impelli minus graue &longs;ur&longs;um ver&longs;us F, ac proindè concedendum erit a&longs;cen&longs;um per BF naturalem pror&longs;us e&longs;&longs;e vel potius in eadem naturali operatione includi debere violentiam motus præ­dicti a&longs;cen&longs;us; &longs;ed vtcunque &longs;it &longs;ufficit nobis vt præ­dicta operatio &longs;it nece&longs;&longs;aria, &longs;it que pror&longs;us impo&longs;&longs;ibi­le vt aliter contingat; cæteriverò eam vocent &longs;iue na­tur alem, &longs;iue violentam ad eorum libitum.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

PROP. II.

Idip&longs;um verificatur in fluidis contentis in eodem &longs;iphone circulari.

PRærerea vt duo corpora in extremitatibus libræ con&longs;tituantur non &longs;emper e&longs;t nece&longs;&longs;e vt corpora grauia A & B affixa &longs;int virgæ alicui rigidæ & con&longs;i­&longs;tenti vt e&longs;t ACB pote&longs;t onim concipi canalis circu­laris AGBF qui &longs;i repleatur aqua vel quolibet alio

fluido liquore cuius pars dex­tera FAG grauior &longs;it quam re­liqua fluidi pars GBF &longs;cilicet &longs;i fluidum FAG fuerit hydrar­girum, FBG verò aqua com­munis, tunc pariter efficietur libra, & centrum grauitatis amborum liquorum non iace­bit in diametro FCG perpendiculari ad horizontem, &longs;ed vltra ip&longs;um inter C & A, &longs;cilicor in puncto aliquo D tunc pariter erit centrum totius magnitudinis flui­di ip&longs;um C & in hoc præci&longs;e fiet &longs;u&longs;pen&longs;io totius flui­di, quia circa ip&longs;um efficiuntur duo motus contrarij, nempe de&longs;cen&longs;us fluidi A & a&longs;oen&longs;us alterius oppo&longs;i­ti fluidi B cùm igitur centrum communis grauitatis D duorum fluidorum di&longs;tet à centro &longs;u&longs;pen&longs;ionis C effi­cietur quoque pendulum, quod circulari motu ex­curret per arcum DE.

Cap. 3. d&etail; momentis grauium in fluido inna­tantium

PROP. III.

Organum in quo videtur motus perpetuus effici po&longs;&longs;e exponitur, atque eius defectus, & infufficientia detegitur.

ET hic breui & non omnino &longs;uperuacanea digre&longs;­&longs;ione indicabo impo&longs;&longs;ibilitatem motus perpetui in machina quæ tantam veri&longs;imilitudinis apparenti­am habere videtur, vt quilibet iuraret tali organo motum continuari facilè po&longs;&longs;e, huiu&longs;modi &longs;peculatio­nem & organi &longs;tructuram mihi olim communicauit amicus optimus Clemens &longs;eptimius Galilei alumnus. is &longs;anè cum contemplaret tympana ver&longs;atilia &longs;eu ro­tas illas quibus nauiculæ trahuntur Pi&longs;is & in Belgio ab vno canaliad alium à vi vnius hominis, qui inter­nam eius periphæriam, accliuem calcando ea&mtail; reuoluit, vt quæ à canibus eodem tympano in coqui­nis verua rotantur, cogitauit eodem modo tympanum efformari po&longs;&longs;e in quo

perpetuò medietas eius &longs;ini&longs;tra à fluido corpor&etail; grauiori quam medietas dextra occupari po&longs;&longs;et. vt in appo&longs;ito &longs;chemat&etail;. &longs;it tympanum æreum AF BG comprehen&longs;um à &longs;u­perficie curua cylindrica ærea & à duabus laminis planis circularibus inter &longs;e parallelis optimè læuiga­tis & cum illa coaptatis conglutinati&longs;que, verùm in­tra tympani cauitatem collocetur lamina plana FCG quæ v&longs;um diaphragmatis præ&longs;tet & medietas cylin­dri FCGA aqua ver hydrargiro repleatur, reliqu&atail; verò medictas BFCG oleo velaere oppleta &longs;it; lami­na verò FCG axi HC annexa & ferruminata intr&atail; tympanum & circa axim fixum C manubrio aliquo H fixè retineri & reuolui po&longs;&longs;it, hac lege vt exactè tangat &longs;uperficies internas ambarum ba&longs;ium plana­rum & cauam &longs;uperficiem curuam eiu&longs;dem tympani: oportet autem vt ad in&longs;tar epi&longs;tomij exacti&longs;&longs;imè dia­phragma illud reuolutum ab&longs;que vlla rima occludat egre&longs;&longs;umque impediat aquæ vel mercurio in &longs;emicy­lindro FAG contento, remanente reliquo &longs;patio G BF aere, vel oleo oppleto, &longs;itque præterea moles to­tius tympani &longs;u&longs;pen&longs;a in ip&longs;o axi C aflixo duobus ful­cris vt liberè circumuolui tympanum po&longs;&longs;it in plano perpendiculari ad horizontem; tunc &longs;i vi manus ma­nubrium H eique annexum diaphragma FCG perpe­tuò in &longs;itu verticali ad horizontem retineretur, pro­culdubio (dicèbat amicus) haberemus in tali ca&longs;u li­bram radiorum æqualium perpetuam imaginariam ACB quæ ab inæqualibus ponderibus premeretur, &longs;cilicèt à pondere emi&longs;phærij mercurialis vel aquei FAG radius CA grauaretur, dum oppo&longs;itus radius C B à leuiori pondere olei, vel aeris deprimeretur. & quia horum inæqualium ponderum centrum grauita­tis &longs;emper in aliquo puncto D intercepto inter C & A caderet, igitur &longs;emper libra AB flecti deberet de­or&longs;um ad partes A, vel potius con&longs;titueretur pendu­lum horizontale CD &longs;u&longs;pen&longs;um in centro C & ideò pendulum de&longs;cendere deberet per arcum DE; qui&atail; verò fluidum grauius FAG de primi non po&longs;&longs;et ob im­pedimentum diaphragmatis FCG in &longs;itu verticali à virtute manus retenti, &longs;equeretur vt vniuer&longs;um &longs;e­micylindricum mercurij comprimendo & calcando curuam &longs;uper&longs;iciem tympani AG, quæ volubilis e&longs;t eam impelleret, proindeque deor&longs;um conuerti debe­ret ab A ver&longs;us G cum à nullo retinaculo impediatur, igitur &longs;emper reuolui po&longs;&longs;et tympanum ab A ver&longs;us G quia &longs;emper per&longs;eueraret eadem cau&longs;a vertiginis &longs;cilicet perpetuò con&longs;eruaretur pendulum CD in &longs;itu horizontali, & ideò &longs;emper premeret & calcaret tym­pani &longs;uperficiem AG; quapropter tali artificio con­&longs;equi po&longs;&longs;e videtur motus perpetuus prædicti tym­pani.

Cap. 2. de momentis grauium in fluido inna­tantium

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

Hoc, vt dixi, tantam veri&longs;imilitudinem præ&longs;efer­re videtur vt nemo ex pluribus amicis quibus hoc ar­tificium communicaui fallaciamin eo latere &longs;u&longs;pica­tus fuerit, nihilominus licèt ego, nun quam ad praxim hoc artificium reducere curauerim, non vereor tamen ab&longs;olutè pronunciare motus perpetuitatem hac via con&longs;e qui non po&longs;&longs;e, quia nimirum per&longs;uadere mihi non valeo grauia corpora moueri vnquam &longs;ponte debere, quando nè pilum quidem magis, quàm prius de&longs;cen­dere valent atque ad centrum terræ accedere neque­unt: cum itaque centrum grauitatis communis D am­borum fluidorum &longs;emper

in eodem plano horizon­tali ABCD retineatur ac &longs;i&longs;tatur mihi omninò im­po&longs;&longs;ibile videtur vt rot&atail; &longs;iue tympanum AGBF con­uertatur ad partes A ver­&longs;us G. Itaque licet centrum grauitatis communis D di&longs;tet à centro &longs;ixo vertiginis C & proinde pendulum horizontale con&longs;tituat; ta­men aio ip&longs;um retineri &longs;u&longs;pendique à vi manus, quæ diaphragma FG retinet ne conuertatur à vi ponderis in centro D operantis, non &longs;ecus ac &longs;i fune-pendulum aliquod CD à &longs;ubiecta manu &longs;u&longs;pen&longs;um deor&longs;um fer­ri non po&longs;&longs;et per arcum DE. & licèt fune-pendulum CD in ca&longs;u no&longs;tro non &longs;it quid continuum & alligatum centro C nihilominus perindè &longs;e habet, cumeius co­natus fiat per arcum DE eo modo præcisè, ac &longs;i cen­tro C alligatum fui&longs;&longs;et; ille verò qui prohibet de&longs;cen­&longs;um corporis grauis D, quod &longs;olummodo moueri per arcum DE pote&longs;t, nece&longs;&longs;ariò impedit operatione&mtail; eius loco motiuam, ideoque fluidum FAG cum omni­nò quie&longs;cat, non poterit impellere, & conuerter&etail; tympanum; nullo enim modo capi pote&longs;t proiectum impelli ab eo corpore quod omninò in quiete con&longs;i­&longs;tit, nam &longs;emper proijciens & impellens impetu & motu locali affectum &longs;it oportet ad hoc, vt proyecto gradum impetus imprimere valeat, cum igitur hy­drargyrum FAG omninò iners &longs;it & motu locali care­at, videtur omninò impo&longs;&longs;ibile vt proiecto &longs;cilicet tympano gradum aliquem impetus imprimere queat, proinde que tympanum non transferetur localimotu, quare tali artificio motus vertiginis eius nedum con­tinuari perpetuò non poterit, &longs;ed neque motum in­coabit. Sed relicta digre&longs;&longs;ione ad rem no&longs;tram redeo.

Cap. 2. de momentis grauium in fluido inna­tantium

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

PROP. IV.

In canali seu &longs;iphone habente duo brachia directa, & perpendiculariter eleuata ad horizontem, fluidi in eo de&longs;cendentis centrum grauitatis cur­uo itinere per lineam parabolicam de&longs;cendit.

IN &longs;iphone TFGV &longs;int duo canales TF & GV pa­ralleli inter &longs;e, & erecti per pendiculariter ad ba­&longs;im FG, & ad horizontem, & quilibet eorum æquè cra&longs;lus &longs;it; capacitas verò portionis cylindri TF &longs;u­pra horizontalem per V eductam vt e&longs;t TA in primo ca&longs;u, & TC in &longs;ecundo, &longs;it æqualis

capacitati GV, quæ &longs;ecetur i&ntail; quotcumque partes æquales à qua ternario men&longs;uratas in X, Y, Z, I, L, 2, & puncta A, B, C, D, E, &longs;int centra grauitatum cylindrorum T F, XF, YF, ZF, & AF, vel CF, pa­riterque H, I, K, L &longs;int centra gra­uitatum cylindrorum GI, GL, G2, GV, & quia centra grauitatum A, & B, bifariam &longs;ecant cylindros T F, XF, ergo TF ad XF &longs;e habet vt AF, ad BF, & per conuer&longs;ione&mtail; rationis, & permutando TF ad AF eamdem rationem habet, quàm TX ad AB, quar&etail; AB &longs;emi&longs;&longs;is e&longs;t ip&longs;ius TX, non &longs;ecus ac HG mediatas e&longs;t cylindri IG, intelligatur aqua primò eleuari i&ntail; &longs;itu T & deprimi in dextro canali in G, & hinc eleua­ta aqua ad I de&longs;cendat à T ad X coniungantur qu&etail; duæ rectæ lineæ AG, & BH &longs;e &longs;ecantes in M, eritque punctum Min horizontali EL con&longs;titutum, propterea quod duo cylindri aquæ AB, & HG æquales &longs;unt in­ter &longs;e, cum &longs;emi&longs;&longs;es &longs;int cylindrorum æqualium TX & IG, ergo altitudo AB ad HG e&longs;t vt eiu&longs;dem cylindri ba&longs;is H ad ba&longs;im A: eadem ratione AE ad LG erit vt ba&longs;is H ad basim A quare altitudo AE ad LG erit vt AB ad HG, sunque duæ rectæ lineæ AE & GL perpendicula res ad horizontalem FG, vel EL, & ideò inter &longs;e paral­lelæ, ergo ob &longs;imilitudinem triangulorum vt AM ad MG ita erit BM ad MH, nec non EM ad ML, & ideo rectæ AG, BH, & EL &longs;e mutuo &longs;ecabunt in eode&mtail; puncto M. po&longs;tea vt moles aquæ XBF vnà cum GHI ad molem aquæ IHG ita fiat di&longs;tantia HB ad BQ, & diuidendo, vt moles aquæ XBF ad GHI ita erit di­&longs;tantia HQ ad QB, ideoque ex elementis mechanicis punctum Q erit centrum grauitatis aquæ XBF vnà cum GHI. quando verò aqua erat in &longs;ummitate T & canalis GLV omninò exhau&longs;tus erat, tunc quide&mtail; centrum grauitatis totius aquæ TAF per&longs;i&longs;tens i&ntail; puncto A medio eiu&longs;dem canalis perindè operare­tur ac &longs;i &longs;u&longs;pen&longs;us fui&longs;&longs;et cylindrus èx puncto A: de­pre&longs;&longs;a po&longs;tmodum aqua v&longs;que ad Y & eleuata v&longs;que ad L in oppo&longs;ito canali, denuo centrum grauitatis re­pertum prædictæ aquæ exi&longs;tet in puncto R & tandem depre&longs;&longs;a aqua v&longs;que ad A in primo ca&longs;u & v&longs;que ad Y in &longs;ecundo & &longs;ubleuata v&longs;que ad V; tunc quide&mtail; centrum grauitatis prædictæ aquæ horizontaliter con­&longs;titutæ præcisè incidet in centro &longs;u&longs;pen&longs;ionis M, prop­terea quòd vt ba&longs;is V ad ba&longs;im A &longs;eù vt cylindrus a­queus GLV ad equè altum cy­
lindrum AEF in primo ca&longs;u vel ad CEF in &longs;ecundo, ita fuit reci­procè di&longs;tantia EM ad ML. o­&longs;tendendum modò e&longs;t punct&atail; A, Q, R, S, M in eadèm linea pa­rabolica e&longs;&longs;e. quia moles aquæ TX æqualis e&longs;t æquæ moli GH I, ergo, XBF vnà cum GHI æ­qualis e&longs;t moli aqueæ TAF; e­rat verò moles aquæ XBF vnà cum GHI ad GHI vt linea HB ad BQ &longs;eu (ducta QN parallel­là AE) vt LE ad EN, ergo FAT ad TX atque &longs;emi&longs;&longs;is illius FA ad huius &longs;emi&longs;&longs;em AB eamdem proportionem habebit qua&mtail; LE ad EN, e&longs;t verò EA ad AF vt MA ad AG, &longs;eù vt ME ad EL, ergo ex æqualitate ordinata EA ad AB eamdem proportionem habebit quam ME ad EN, & per conuer&longs;ionem rationis EA ad EB erit vt EM ad MN, &longs;eù vt EB ad NQ, erunt igitur tres continuæ pro portionales EA, EB, & NQ in eadem ratione qua&mtail; habet EM ad MN, quare quadratum ex EM ad qua­dratum ex MN eam proportionem habebit, qua&mtail; AE ad NQ: ideoque puncta A & Q &longs;unt in parabol&atail; cuius vertex M. quapropter aqua in prædicto &longs;iphone dum ad æquilibrium de&longs;cendit mouetur eius centrum grauitatis in linea parabolica; quod fuerat o&longs;tendendum.

Cap. 2. de momentis grauium in fluido inna­tantium.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

PROP. V.

Ijsdem po&longs;itis &longs;i canales &longs;iphonis æquèlati angulum con&longs;ti­tuentes æquè ad horizontem inclinati fuerint idip&longs;um demon&longs;tratur.

SI po&longs;tea &longs;ipho inuer&longs;us eiu&longs;dem amplitudinis an­gularis fuerit, vt nimirum &longs;emi&longs;&longs;es brachiorum AF & FL æquè &longs;int ad horizontem EL inclinata effi­ciatur què hi

&longs;c&longs;celium tri angulum EF L & brachij &longs;upremi qua­drans EA æ­quale &longs;it FL, &longs;iue FE. dico denuò quòd aqua totius brachij F2. cuius &longs;emi&longs;­&longs;is e&longs;t AF dum fluit per canalem FL4 &longs;ur&longs;um & de&longs;cendit per 2 A; tunc pariter eius centrum grauitatis per parabolam deor&longs;um fertur. diui&longs;is æqualibus partibus in punctis A, B, C, D, E, & F, H, I, K, L, quæ centra grauitatu&mtail; partium aquæ e&longs;&longs;e intelligantur vt prius, & ductis ad horizontalem perpendicularibus AG, BV, CN, DO, FM, H3, &c. pariterque coniunctis rectis DK, CI, BH. quia anguli ad L, E æquales &longs;unt in i&longs;o&longs;cele, & &longs;unt quoque anguli recti O & T, & hypothenu&longs;æ DE, KL &longs;unt inter &longs;e æquales, ergo in &longs;imilibus triangulis DOE, & KTL latera DO, KT æqualia erunt & recta OE æqualis erit TL, & addita communi TE erit LE æqualis OT quæ non minus quàm DK bi&longs;&longs;ecta erit in puncto Z, propter æquidi&longs;tantiam & æqualitatem la­terum DO, & TK. &longs;imiliter reliquæ rectæ lineæ NY & CI æquales erunt prioribus, & bi&longs;&longs;ectæ in puncto P, idemque de reliquis dicendum e&longs;t. & quia canales, & moles aqueæ in eis contentæ AB, & FH, æquales &longs;unt, ergo BFH æqualis e&longs;t AF; fiat iam HB ad BQ, vt BFH ad FH, vel potius vt FA ad AB: quare &longs;emi&longs;­&longs;es antecedentium ad ea&longs;dem con&longs;equentes in eadem ratione erunt, nempè vt EA ad AB, ita erit XB ad B Q, & per conuer&longs;ionem rationis EA ad EB &longs;eu AG ad BV, vel GE ad EV, & tandem vt duplum GM ad duplum MN erit vt BX ad XQ, &longs;eu vt VX ad XN, vel vt BV ad QN. igitur erunt tres continuæ propor­tionales AG, BV, & QN in eadem ratione quam ha­bet MG ad MN, quare vt quadratum MG ad quadra­tum MN, ita erit longitudine AG ad QN ideoqu&etail; duo puncta A & Q in parabola erunt.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

Con&longs;tat ergo quòd &longs;i brachia &longs;iphonis perpendicu­laria fuerint ad horizontem, &longs;iuè ambo fuerint eiu&longs;-dem latitudinis &longs;iuè non, &longs;emper centrum communis grauitatis fluidi in de&longs;cen&longs;u parabolam de&longs;cribet; &longs;i verò brachia &longs;iphonis æquè inclinata ad horizontem fuerint, de&longs;cribet eius centrum in de&longs;cen&longs;u parabo­lam quotie&longs;cumque brachia æquè cra&longs;&longs;a fuerint.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

COROLLARIVM I.

Siverò in eodem angulari &longs;iphone vnum brachium dilatatum, alterum verò gracile fuerit, tunc eius cen­trum in de&longs;cen&longs;u curuam de&longs;cribet hyperbola&mtail; &ecedil;mulantem.

COROLLARIVM II.

Et tandem &longs;i vnum brachiorum perpendicular&etail; fuerit ad horizontem, reliquum verò inclinatum in de­&longs;cen&longs;u de&longs;cribet commune centrum grauitatis curuam ellip&longs;im æmulantem.

His præmi&longs;&longs;is declarari debet altera libræ, &longs;eu &longs;i­phonis proprietas, in quo centrum grauitatis eius mouetur non quidem motu obliquo, & curuo, &longs;ed per lineam rectam ad horizontem perpendicularem, pro cuius intelligentia præmittendum e&longs;t, quod.

PROP. VI.

Duo ponder a inæqualia fune non graui circa trochleam reuo­luto &longs;u&longs;pen&longs;a, dum vnum eorum a&longs;cendit centrum gra­uitatis eorum per lineam rectam ad horizontem perpendicularem deprimitur.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

SIt pondus A maius, B verò minus alligata extre­mitatibus funis ADB, qui &longs;upponatur omninò grauitate carere, & reuoluatur circa trochleam CDE conuertibilem circa axim fixum F. patet quòd funes AC, & BE perpendiculariter ad ho­

rizontem CE prementes, & exten&longs;i contingunt peripheriam rotæ in ter­minis oppo&longs;itis C, & E eiu&longs;dem dia­metri, &longs;eu libræ horizontalis, ergo funes CA, & EB &longs;unt inter &longs;e paralle­li; coniungatur po&longs;tea recta linea AB, &longs;eceturque bifariam in G, & vt pon­dus A ad B ita fiat di&longs;tantia BI ad IA manife&longs;tum e&longs;t (ex mechanicis) punc­tum I e&longs;&longs;e centrum grauitatis com­munis duorum colligatorum ponde­rum A & B, funis enim hanc propor­tionem non alterat, cùm nullius gra­uitatis &longs;upponatur: a&longs;cendat po&longs;tea pondus minus B vbicumque ad L, & deprimatur ma­ius pondus A v&longs;que ad K. dico quod ambo in com­muni centro grauitatis de&longs;cendunt circa libræ cen­trum, &longs;eu fulcimentum &longs;tabile G motu directo, & per­pendiculari ad horizontem. coniungatur recta line&atail; KL quia funis ADB æqualis, imò idem e&longs;t, quàm K DL, igitur ablato communi ADL erit de&longs;cen&longs;us AK æqualis a&longs;cen&longs;ui BL; quare in triangulis &longs;imilibus ob æquidi&longs;tantiam laterum AK & BL homologorum vt AK ad BL ita erit AG ad GB & ita pariter KML

ad M, &longs;untque latera AK & BL æqualia inter&longs;&etail; ergo &longs;e mutuò bifariam &longs;ecabunt rectæ coniungentes AB, & KL in eodem puncto G; idemque continget translatis ponderibus in N, & O, & ideo punctum G erit centrum, &longs;eu &longs;tabile fulcimentum libræ AB quo­modolibet reuolutæ: ducatur tandem per I recta li­nea IP parallela funibus &longs;ecans libras KL, & NO i&ntail; punctis M, & P patet libras in eadem proportione re­ciproca &longs;ecari in punctis I, M, P, quam habent oppo&longs;i­ta pondera proindeque eadem puncta erunt centr&atail; grauitatum, earumdem librarum cum ponderibus ap­pen&longs;is; quapropter licet minus pondus B a&longs;cendat per BLO, tamen ambo pondera A, & B in communi cen­tro grauitatis eorum I &longs;u&longs;pen&longs;a circa centrum firmum G, & in extremo fune-penduli GI de&longs;cendunt no&ntail; circulari, &longs;ed directo motu perpendiculari ad hori­zontem ab I per M & P, quod fuerat o&longs;teudendum.

Cap. 2. de momentis grauium in fluido inna­tantium.

PROP. VII.

Id ip&longs;um osten ditur, cùm pondera in peripherijs inæqua­libus, & concentricis eiu&longs;dem trochleæ reuoluuntur.

SIt trochlea CDE circa axim F conuertibilis, & in ea &longs;it alia concentrica circumferentia RSQ, & funi SQB alligetur pondus B, alij verò funi DEA alli­getur pondus A &longs;intque funes nullius ponderis; o&longs;ten­detur, vt in præcedenti, funes EA, & BQ e&longs;&longs;e inter&longs;e parallelos; po&longs;tea coniungatur recta AB, atque vt pon­dus A ad B ita reciprocè fiat di&longs;tantia BI ad IA; patet punctum I e&longs;&longs;e centrum grauitatis communis ponde­rum A, & B (cum funes nullius ponderis &longs;upponantur) deinde reuoluta trochlea a&longs;cendat pondus B ad L, & oppo&longs;itum pondus A de&longs;cendat v&longs;que ad K coniunga­turque recta KL &longs;ecans rectam AB

in G. dico duo pondera A, & B i&ntail; communi eorum centro grauitatis I circa libræ centrum &longs;tabile G mo­tu directo, & perpendiculari ad horizontem de&longs;cendere. quia in tro­chleæ reuolutione tantumdem de&longs;cen­dit terminus funis A quanta e&longs;t ex­plicatio funis è rota CDE, & pon­dus B a&longs;cendit quantum funis BQS circumuoluitur circa rotam QSR cùmque duæ rotæ concentricè con­nexæ &longs;imul tempore reuoluantur cir­ca &longs;ixum axim F, ergo de&longs;cen&longs;us AK ad a&longs;cen&longs;um BL eamdem proportio­nem habet, quam peripheria CDE ad peripheriam R SQ, &longs;eu eamdem proportionem, quam habet radius FE ad radium Fque quare in triangulis AGK, & BGL &longs;imilibus, ob æquidi&longs;tantiam laterum AK, & BL, erit AG ad GB vt KG ad GL, &longs;eu vt AK ad BL; proindeque in eodem puncto fixo G duæ libræ AB, & KL &longs;e mutuò &longs;ecabunt in eadem proportione, quam habent motus eorumdem terminorum, vnde, ex mechanicis, erit punctum G centrum, & fulcimentum firmu&mtail; vtriu&longs;que libræ AB, & KL po&longs;tremò ducatur per I rectà IM parallela funibus, &longs;eu perpendicularis ad horizontem &longs;ecans KL in M planè &longs;ectæ erunt duæ li­bræ prædictæ in I, & M in eadem proportione reci­proca ponderum &longs;u&longs;pen&longs;orum, ideoque puncta I, & M erunt centra grauitatum vtriu&longs;que libræ: quare li­cet pondus B a&longs;cendat p BL, tamen verum e&longs;t duo pondera AB in communi centro grauitatis I &longs;u&longs;pen&longs;a circa centrum firmum G, & in termino fune-penduli GI de&longs;cendere directo motu, & perpendiculari ad horizontem per IM, & hoc erat o&longs;tendendum.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

Huiu&longs;modi mechanicæ &longs;peculationes maximè con­ferunt ad intelligentiam motus corporum in fluidis, pro cuius declaratione primò con&longs;iderari debet.

PROP. VIII.

Quaratione fiat Motus fluidi in &longs;iphone continuato, & in &longs;eip&longs;um reflexo.

SIt igitur &longs;ipho ABDG in &longs;e ip&longs;um reflexus cuius brachia lateralia BN & GO directa &longs;int, in­ter &longs;e parallela, & ad horizontem perpendiculariter erecta & æquè ampla. includatur po&longs;tea gutta aliqua mercurij BC, quæ in fi&longs;tulis angu&longs;tis retinetur in eo­dem &longs;itu collecta, reliqua verò cauitas eiu&longs;dem fi&longs;tulæ BAGDC repleatur aqua; tunc ductis à punctis B, & C & à centro grauitatis guttæ mercurialis H tribus li­neis rectis parall elis horizonti BG, HI, & CF, & &longs;ec­ta HI bifariàm in L; patet quòd duo grauia, mercu­rius nempe BC, & aqua GF &longs;u&longs;penduntur in eade&mtail; libra imaginaria HI, quia hæc duo corpora motibus contrarijs agitantur &longs;u&longs;pendunturque ab eadem li­bra horizontali: nec actionem eorumdem corporum impediunt, vel adiuuant &longs;upremæ, vel infimæ aquæ partes; quando quidem aqua AB,

æquilibratur collaterali AG cù&mtail; &longs;int homogeneæ & æquè altæ, non &longs;ecùs infimæ aquæ partes CD & F E inter &longs;e æquilibrantur; quare ac­tioni compre&longs;&longs;iuæ mercurij CB, tan­tummodo contraponitur pondus aquæ FG in eodem &longs;itu horizontali con&longs;titutæ. fiatiam vt pondus mer­curij CB ad grauitatem aquæ FG ita reciprocè di&longs;tantia IM ad MH, quare punctum M erit centrum gra­uitatis duorum corporum BC, & GF, cùmque libr&atail; imaginaria HI fulciatur in puncto L rectæ LK per­pendiculariter horizonti eductæ ex infimo &longs;itu fi&longs;tu­læ, vbi bifariam libra, & magnitudines fluidæ &longs;ecan­tur, igitur con&longs;tituitur fune-pendulum LM, & proin­dè, iuxtà leges mechanices, libra flectetur de&longs;cenden­do corpus BC, & a&longs;cendendo aquam FG, & hoc per­ficitur propterea quòd centrum communis grauita­tis M nece&longs;&longs;ariò labitur deor&longs;um iuxta penduli na­turam. &longs;ed prædictus motus centri grauitatis M non e&longs;t circularis, &longs;ed e&longs;t directus ad horizontem perpen­dicularis, per lineam MQ non &longs;ecùs ac in trochlea con­tingit vt dictum e&longs;t; huius operationis verò progre&longs;-&longs;us talis e&longs;t, cùm primum cvlindrus mercurij CB fer­tur deorsùm transferendo eius centrum H in N, de­nuò comparatur cum alio aquæ cylindro æquali ip&longs;i FG è regione po&longs;ito, cuius centrum grauitatis erit punctum O, & tunc denuò creatur noua libra horizon­talis NO &longs;ecta à rectis LP & MQ parallelis ENGO, in P & Q cuius centrum P, quia denuò partes aquæ collaterales &longs;upernæ & infernæ &longs;ibi ip&longs;is æquilibratæ non adiuuant, neque impediunt duo æqualia corpo­ra mercuriale ex N, & aqueum ex O, quæ ad inuicem comparantur in eadem libra horizontali, cumque hæc à parallelis lineis HN, MQ, & IO in ei&longs;dem rationi­bus diuidatur, perductum erit centrum grauitatis pr&ecedil;­dictorum corporum ad punctum Q, vnde patet de­&longs;cendi&longs;&longs;e per rectam lineam MQ perpendicularem ad horizontem, perdurabitque eius de&longs;cen&longs;us, quou&longs;que corpus mercuriale CB ad &longs;itum infimum fi&longs;tulæ DE perducatur, quando nimirum eius grauitatis centrum H præcisè infimum &longs;itum K fi&longs;tulæ attinget.

Cap. 2. de momentis grauium in fluido inna­tantium

Cap. 2. de momentis grauium in fluido inna­tantium

Nec dicas fictionem e&longs;&longs;e quòd ad&longs;it libra horizon­talis directa HI, quæ perpetuò renouetur, nam reue­rà fulciuntur, &longs;u&longs;tentanturque duo cylindri CB, & G F à plano aquæ &longs;ubiectæ CF quod quidem, mobile e&longs;t, cùm cedat de&longs;cen&longs;ui mercurij CB & &longs;uperficies F eleuetur eodem tempore & pari velocitate circa eius punctum intermedium, igitur prædicta duo corpora BC, & GF dum ambo premunt libram fluidam &longs;ub­iectam &longs;uis ponderibus, & coguntur moueri &longs;imùl æ­què velociter contrarijs lationibus nece&longs;&longs;ariò libram con&longs;tituunt, quæ in &longs;uo centro grauitatis energia&mtail; vniuer&longs;æ &longs;uæ compre&longs;&longs;ionis exercent, verum tame&ntail; e&longs;t quòd prædicta libra non flectitur, &longs;ed continentèr renouatur in &longs;itu horizontali, quandoquidem aqu&atail; eleuata iam non amplius agit contra pre&longs;&longs;ionem mer­curij CB vt dictum e&longs;t, propterea quòd æquilibratur cum aqua collaterali &longs;upra mercurium CB eleuata.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

PROP. IX.

Corpus aqua grauius in ea demer&longs;um dum de&longs;cendit consti­tuit cum æqualimole collateralis fluidi libram æqualium radiorum, cuius centrum grauitatis continenter de&longs;cendende eleuat leuiorem aquam col­lateralem, &longs;emperque renouatur horizontalis libra.

HOc præmi&longs;&longs;o intelligatur iam vas aquà plenum RSTX, & intra eius profunditatem appona­tur pri&longs;ma marmoreum ABCD, & producantur eius ba&longs;es horizontales AB, & CD

v&longs;que ad G & H, atque planu&mtail; AD producatur &longs;ur&longs;um, & deor­&longs;um v&longs;que ad M, & V perpendi­culariter ad horizontem. hic iam habemus &longs;iphonem oblongum in &longs;e ip&longs;um circumductum, vt in pr&ecedil;­cedenti propo&longs;itione expo&longs;itum fuit, quia aqua BM GHVC ambit pri&longs;ma &longs;upernè, lateraliter, & infernè, nec moueri pote&longs;t de&longs;cendendo pri&longs;ma AC quin aqua &longs;ubiecta CID è &longs;uo loco expellatur, & lateralitèr fluat ver&longs;us P, circumfera turque &longs;ur&longs;um v&longs;que ad locu&mtail; relictum à pr&ecedil;dicto pri&longs;mate lapideo in E. &longs;unt igitur duæ partes MT, & MS veluti duo canales laterales &longs;iphonis, quitamen &longs;e&longs;e contingunt in communi la­tere MV; prætereà duæ portiones aquæ &longs;upremæ XA, & MG cùm &longs;int homogeneæ, æquè graues &longs;pecie, & æque altæ, &longs;e mutuò æquilibrantur, pariterque duæ portiones aqueæ &longs;ubiectæ CV, & DS pariter æquili­brantur, vnde patet quòd tantummodo comparari debent inter &longs;e duo corpora collateralia &longs;axum nimi­rum BD, & aqua AH, quæ ab ei&longs;dem planis horizon­talibus BG, & HC comprehenduntur, & hæc &longs;imiliter fulciuntur &longs;u&longs;tentanturque à plano aquæ &longs;ubiectæ H C non firmo, & impermeabili, &longs;ed facilè à &longs;uo loco amouibili & cedenti. in&longs;i&longs;tunt igitur prædicta duo cor­pora BD, & AH non &longs;ecùs &longs;u&longs;pen&longs;a ac &longs;i &longs;uper libram HC inniterentur; huius verò centrum mobile e&longs;&longs;et punctum intermedium D, vbi nimirum libra HC bi­fariàm &longs;ecatur, & &longs;i à centro grauitatis O &longs;axi BD ad centrum P grauitatis aquæ AH recta linea coniunga­tur, eaque &longs;ecetur in Y reciprocè &longs;ecundùm propor­tionem grauitatum eorumdem corporum, patet Y e&longs;­&longs;e centrum grauitatis communis &longs;axi BD, & aquæ A H, cùmque libra PO &longs;ecetur bifariàm à plano MV in Q iam con&longs;urget fune-pendulum QY horizontaliter excen&longs;um versùs O ob exce&longs;&longs;um grauitatis &longs;axi &longs;upra aquæ pondus &longs;pecificum, igitur nece&longs;sè e&longs;t vt tot&atail; libra flectatur deorsum, & &longs;ic &longs;axum BD de&longs;cendet. Quia verò in de&longs;cen&longs;u aqua &longs;ubiecta expul&longs;a ex I curuo iti­nere &longs;ur&longs;um fluit per ZF v&longs;que ad E denuò renouatur libra horizontalis, comparanturque inter &longs;e &longs;axum B D cum aqua collaterali in nouo &longs;itu horizontali de­pre&longs;&longs;iori exi&longs;tente, igitur denuò eadem proportione di&longs;&longs;ecta libra imaginaria horizontali, fune-pendulum æquale priori eadem vi flectetur deorsum, de&longs;cendetque centrum grauitatis eius motu perpendiculari ad hori­zontem quòu&longs;que ad fundum va&longs;is &longs;axum pertingat.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium

Cap. 2. de momentis grauium in fluido inna­tantium

PROP. X.

Idip&longs;um sentingit, &longs;ed inuer&longs;o ordine cum corpus de­mer&longs;um minùs graue aqua collaterali fueris.

SI po&longs;tea pri&longs;ma BD fuerit ligneum, & minùs gra­ue &longs;pecie quam aqua AH, tunc ij&longs;dem manen­tibus &longs;olummodò centrum grauitatis communis Y cadet ad partes aquæ inter Q & P, & proindè vniuer­&longs;um graue compo&longs;itum ex aqua, & ligno vim faciet impellendo deor&longs;um centrum gra­

uitatis Y, & ideò vehementiùs con­primetur aqua &longs;ubiecta HDVS, hæc verò ob eius continuitatem & naturam con&longs;i&longs;tentem, quæ pre&longs;­&longs;ioni non cedit, nece&longs;&longs;ariò impel­letur versùs I, & &longs;ic vim faciet &longs;ur­&longs;um exprimendo ligni &longs;uperficiem DC; at dum lignum a&longs;cendit, oportet vt expellat è &longs;uo loco incumbentem aquam E, quæ tran&longs;uer&longs;ali & obliquo motu perduce-tur ab E per FZ versùs I, & &longs;ic à prædicto motu circu­lari aquæ ambiemis lignum expelletur &longs;ursùm; atta­men ratio mechanica huius actionis pendet ex eo, quòd libra horizontalis imaginaria PO flectitur per­petuò deorsùm quidem ad partes centri grauitatis Y circa centrum Q, & &longs;ursùm ad partes O. &longs;ed &longs;ummo­perè animaduertendum e&longs;t prædictam libram imagi­nariam horizontalem renouari &longs;ucce&longs;&longs;iuè prout lignum a&longs;cendit, comparaturque cum alijs lateralibus pri&longs;ma­tibus aqueis, quæ &longs;ucce&longs;&longs;iuè offendit intercepta in­ter prædicta plana horizontalia GB, & HC: nece&longs;sè ergo e&longs;t vt lignum prædictum numquàm quie&longs;cat in­tra aquam demer&longs;um quòu&longs;que ad &longs;upremam libellam aquæ RX perducatur; in&longs;uperque aliqua eius por­tio emineat.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium.

COR OLLARIVM.

Hinc patet veritas Archimedei a&longs;&longs;umpti, quòd fluidi con&longs;i&longs;tentis natura requirit vt partium eius æ­què iacentium magis compre&longs;&longs;æ &longs;ursùm impellant partes minus pre&longs;&longs;as perpendiculariter ad horizontem.

Quia aqua &longs;ubiecta HCTS ob eius con&longs;i&longs;tentia&mtail; non conden&longs;atur, & mobilis e&longs;t, quia fluida, ergo li­bram flexibilem con&longs;tituit, e&longs;tque pars &longs;ubiecta HV magis compre&longs;&longs;a quàm DT (propterea quòd parsa­quea GD grauior e&longs;t ligno AC) igitur libra fluida HDC flecti debet de&longs;cendendo HD & DC a&longs;cen­dendo, quare tota aqua HSVD deorsùm depre&longs;&longs;a im­pellet aquam DVTC &longs;ursùm.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium.

PROP. XI.

Si verò corpus &longs;olidum ponitur &longs;upra aquæ libellam, tunc de&longs;cen&longs;us communis centri grauitatis non efficietur per lineam perpendicularem ad horizontem &longs;ed motu curuo per parabolam.

IN progre&longs;&longs;u prædictæ operationis notabilis e&longs;t va­riatio &longs;itus centri grauitatis eius & mechanicæ eius operationis.

Sit igitur in eodem va&longs;e pri&longs;ma ligneum ABCD perductum ad &longs;upremam aquæ libellam RX, tunc &longs;i­militer inter &longs;e comparantur duo pri&longs;mata BD ligno­um, & AH aqueum in eodem plano horizontali &longs;u­biecto HC in&longs;i&longs;tentes, & proindè

efficitur-libra imaginaria PO mo­bilis circa eius fulcimentum Q, & centrum grauitatis eorumdem cor­porum cadit ad partes aquæ nem­pèin Y inter centrum Q & extremitatem radij P. hinc ergo &longs;e quitur vt prædicta libra flecti debeat deorsùm ad partes Y & &longs;ur&longs;um a&longs;cendatterminus O vnà cum li­gno versùs aquæ libellam fupremam RX, igitur por­tio aliqua ligni &longs;uprema eleuabitur &longs;upra prædictam aquæ libellam, vt patet in po&longs;trema figura, & tunc quidem &longs;ucce&longs;&longs;iuè imminuitur pri&longs;ma aqueum GD prout magis ligneum pri&longs;ma exurgit, eminetque &longs;upra aqu&ecedil; libellam, & in prædicto a&longs;cen&longs;u dum collaterale pri&longs;-ma aqueum imminuitur, pondus eius quòd prius &longs;u­perabat grauitatem ligni BD, tandem po&longs;t continuam ponderis aquæ diminutionem reddetur præcisè æqua­le ponderi cylindri lignei BD, & tunc coniunctis centris grauitatum eorum à rect&atail;
PO hæc quidem bifariàm &longs;ecabi­tur in termino Q & ibidem erit eius centrum, atque fulcimentum ha­bebitque pondus ligni BD ad pon­dus aquæ GD &longs;ibi æquale eamdem proportionem, quam habet reciprocè PQ ad QO, & proindè centrum grauitatis commune Y incidet præ­cisè in centro &longs;eù fulcimento libræ que igitur æquili­bratis prædictis ponderibus libra quie&longs;cet, nec pri&longs;­ma ligneum BD vlteriùs a&longs;cendet, neque denuò deorsum decidet ni&longs;i ex accidenti ratione impetus acqui&longs;iti.

Cap. 2. de momentis grauium in fluido inna­tantium.

Hinc patet quòd quando primò lignum BD exur­gere incipit &longs;upra aquæ libellam RX tunc continen­ter magis ac magis centrum communis grauitatis Y motu obliquo, & curuo a&longs;cendit quòu&longs;que coniunga­tur cum fulcimento Q libræ PO &longs;ursùm tran&longs;lat&ecedil;, non &longs;ecùs, ac in &longs;iphone aqua eleuata in vno eius bra­chio de&longs;cendendo perducit centrum grauitatis eius per curuam lineam parabolicam, vt dictnm e&longs;t; con­cipi ergo debet &longs;ipho inæqualium brachiorum quando primum ba&longs;is &longs;uprema AB ligni attingit aquæ libel­lam, & quia tunc exce&longs;&longs;us grauitatis &longs;pecificæ aquæ AH &longs;upra pondus ligni BD perindè agit ac &longs;i aliud fluidum æquè graue &longs;pecie ligno ip&longs;i BD & maioris molis &longs;upra ba&longs;im HD in&longs;ifteret procul dubio ad ma­iorem &longs;ublimitatem eleuaretur prædictum fluidu&mtail; minùs graue &longs;pecie, quàm aqua AH, cuius ab&longs;olutum pondus æquale e&longs;&longs;et ponderi eiu&longs;dem aquæ commu­nis AH, quare ab eleuatiori loco fluidum prædictum deorsùm excurrendo eleuaret lignum depre&longs;&longs;um BD præcisè vt in &longs;iphone &longs;uperiùs expo&longs;ito contingeret.

Cap. 2. d&etail; momentis grauium in fluido inna­tantium.

Ex hac theoria facili negotio re&longs;olui ac demon&longs;tra­ri po&longs;&longs;unt omnes propo&longs;itiones, quæ ab Archimed&etail; in primo de infidentibus humido demon&longs;trantur.

PROP. XII.

In a&longs;cen&longs;u, vel de&longs;cen&longs;u &longs;olidi in fluide neque libra linearis e&longs;t, neque habet centrum grauitatis in vno puncto &longs;ed libra e&longs;&longs;e &longs;olet &longs;uperficialis, cuius fulci­mentum e&longs;t linea circa centrum figuræ, & grauitas communis exercetur quoque in linea aliqua.

SOllummodò indicabo non &longs;emper v&longs;urpari in præ­dicta mechanica operatione punctum, quod con­mune centrum grauitatis vocari vulgò &longs;olet; propte­rea quòd libra compo&longs;ita ex &longs;olido & fluido ambien­te non &longs;emper linearis e&longs;t, &longs;ed &longs;uper ficiem aliquando componit, in qua nedum fulcimentum, &longs;ed etiam lo­cus vbi exercetur communis grauitas linea e&longs;&longs;e &longs;olet aliquando recta, aliquando curua, & multoties com­po&longs;ita ex pluribus rectis. &longs;i enim in medio aquæ im­mergatur directè & perpendiculariter ad horizontem pri&longs;ma vel cylindrus &longs;olidus, tunc quidem dum pri&longs;­ma de&longs;cendit, vniuer&longs;a aqua illud ambiens &longs;ur&longs;u&mtail; eleuatur. vel illo a&longs;cendente hæc deprimitur, com­parari ergo debet pri&longs;ma comprehen&longs;um cum anulo &longs;eu potiùs cum fi&longs;tula fluida id ambiens, & &longs;ic effici­tur libra quædam plana cuius fulcimentum erit linea in confinio cylindri demer&longs;i, & fluidi ambientis ex­ten&longs;a pariterque locus, vbi communis grauitas exer­cetur non erit punctum, &longs;ed erit quoque linea in eo­dem plano horizontali producta; &longs;ed facilitatis gra­tia concipi debet &longs;ector aliquis in prædicto plano ex centro prædictæ libræ &longs;uperficialis in axe cylindri con&longs;tituto v&longs;que ad &longs;uperficiem aquæ ambientis, qu&ecedil; contrarijs motibus vnà cum cylindro mouetur; &longs;eù potius concipi debet radius, &longs;eù &longs;emidiameter non in diui&longs;ibilis, &longs;ed phy&longs;ica, & h&ecedil;c v&longs;urpari pote&longs;t vt libra particularis cum &longs;uo fulcimento, & centro grauita­tis, vniuer&longs;a verò libra &longs;uperficialis compo&longs;ita erit ex pluribus, & innumeris libris radio&longs;is, vt dictum e&longs;t, & hæc innui&longs;&longs;e modò &longs;ufficiat in hac generali præpa­ratione, inferiùs enim accuratiùs exponentur.

Cap. 2. de momentis grauium in fluido inna­tantium.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Quodlibet corpus fluidum eorum quæ innituntur &longs;uperficiei Telluris graue e&longs;t, exercetque vim &longs;uæ grauitatis etiam dum in proprio loco, & in ip&longs;omet fluido vniuer&longs;ali &longs;ui generis con&longs;i&longs;tit, ac quie&longs;cit.

CAP. III.

SVppo&longs;uimus cum Archimede aquam, & reliqu&atail; corpora fluida terram ambientia vi propriæ grauitatis compre&longs;&longs;ionem vniformem exercere ver&longs;us centrum telluris, ex quo &longs;ubindè fit vt &longs;phæricè circa terræ centrum di&longs;ponantur. præterea &longs;uppo&longs;uimus cum eodem Archimede partes eiu&longs;dem fluidi minùs pre&longs;&longs;as expelli ac &longs;ubleuari &longs;ur&longs;um à partibus eiu&longs;dem fluidi magis compre&longs;&longs;is, & grauatis; ex qua hypothe­&longs;i deducitur quodliber fluidum, veluti aqua e&longs;t, gra­uitatem habere eamque exercere etiam in proprio loco, & naturali regione, &longs;cilicèt aquam ip&longs;am dum in tota aqua quie&longs;cit tunc quoque grauitatem exercere &longs;ubiecta corpora comprimendo.

Ex Archi­mede dedu­cunt aquam in ipsa aqua non grauita­re, & id ipsum Peripatetici affirmaret.

Hoc autem à plurimis negatur qui putant Archi­medem oppo&longs;itum &longs;en&longs;i&longs;&longs;e. idip&longs;um quoque negant aliqui peripatetici qui cen&longs;ent non &longs;emper veru&mtail; e&longs;&longs;e quòd partes &longs;uperiores corporis grauis compri­mant, & vim inferant inferioribus, & contiguis, ni&longs;i infimæ partes leues &longs;int ab&longs;olutè, vel re&longs;pectiuè, vnde

concedunt terram exemp. gr. &longs;uper aquam, aut &longs;uper ae­rem po&longs;itam, vim, & operationem grauitatis & com­pre&longs;&longs;ionis exercere, non itidem aquam &longs;upra ip&longs;a&mtail; terram collocatam, nec aerem aquæ incumbentem, imò nec aerem &longs;upra aerem con&longs;titutum, nec aquam &longs;upra aquam po&longs;itam. huiu&longs;modi propo&longs;itionem tali ratiocinio confirmare nituntur, cum Natura cau&longs;a, & principium motus &longs;it, nec operetur fru&longs;tra &longs;ed ad cer­tum finem, & ad bonum, proculdubio ordinauit mo­tum naturalium corporum ad certum finem, & ad bo­num, &longs;cilicèt ad con&longs;eruationem, & quia actus, &longs;eù perfectio quam appetunt, & quam acquirere nitun­tur corpora grauia, & leuia dum mouentur e&longs;t migra­tio, & debita con&longs;titutio in proprijs locis naturali­bus, grauium nempè de or&longs;um, & leuium &longs;ursùm, hine &longs;equitur quòd po&longs;t quam ad debita loca naturalia per­ducta &longs;unt, motus omninò ce&longs;&longs;at, vtpotè naturæ de&longs;i­derio, & fine expleto, eo quòd vt ait Ari&longs;toteles Na­tura non mouet corpus aliquod vt ipsum moueat, &longs;cili­cèt vt ip&longs;um perpetuò, & in infinitum agitet, &longs;ed tan­tummodo vt illud ad terminum, & finem perducat vt ibidem quie&longs;cat; verùm facultates aut virtutes quibus &longs;ublunaria corpora ad propria loca feruntur nil aliud &longs;unt, quàm grauitas aut leuitas. igitur huiu&longs;­modi facultates ordinatæ &longs;unt ad perducenda elemen­taria corpora ad propria loca vt ibidem quie&longs;cant; nec vlteriùs v&longs;um aliquem habere po&longs;&longs;unt, quando­quidem &longs;i præterea motum pro&longs;e querentur in &longs;uis lo­cis perturbarent & confunderent naturalem fituatio-nem eorumdem corporum. & profectò e&longs;t con&longs;enta­neum vt elementa non nitantur de&longs;erere propria lo­ca, & propterea careant illo naturali &longs;timulo &longs;eu prin­cipio motus quo impellebantur antequam ad &longs;ua na­turalia loca perueni&longs;&longs;ent; hinc deducitur nullum ele­mentum in proprio loco grauitatem, aut leuitatem habere, &longs;ed aqua in ip&longs;a aqua po&longs;ita in propria, & na­turali regione degit & &longs;ic aer in aere, ergo neutrum horum elementorum grauitatem in &longs;uo loco habet, aut exercet. & primo quoad Archimedem pertinet videntur aduer&longs;arij nequaquam tanti viri mente&mtail; a&longs;&longs;equuti &longs;ui&longs;&longs;e vt ex eius verbis &longs;atis &longs;uperque patet. vt verò Peripateticis fiat &longs;atis, ne dum nullam lenita­tem po&longs;itiuam in natura dari o&longs;tendam, &longs;ed præterea probabo fal&longs;um e&longs;&longs;e quòd po&longs;t quam corpora natura­lia ad &longs;ua loca perueniunt & ibidem quie&longs;cunt graui­tas v&longs;um non habet, ni&longs;i ad perturbandum pr&ecedil;clarum ordinem vniuer&longs;i; nam è contra &longs;uadere conabor tunc præcisè corpora grauitatem exercere cùm in &longs;uis lo­cis quie&longs;cunt, imò cau&longs;am, quare in &longs;uis locis quie­&longs;cunt, e&longs;&longs;e quia pondus exercent, &longs;ed prius perpenden­da e&longs;t actio ip&longs;ius grauitatis, & quidnam poti&longs;&longs;imu&mtail; efficiat pondus dum comprimit; & profectò actio & compre&longs;&longs;io corporis grauis non e&longs;t tran&longs;itus localis pilæ ferreæ v.g. dum ver&longs;us terram de&longs;cendit, nec præterea e&longs;t &longs;implex contactus quo coniungitur cum &longs;uperficie telluris &longs;ubiectæ, &longs;ed e&longs;t vis, & energia, qua impellitur deor&longs;um &longs;tringiturque veluti prælo cum ip&longs;a terra; veluti cum pondus in trutina appenditur licet quie&longs;cere videatur exercet actionem quamdam con­pre&longs;&longs;iuam tantæ energiæ quanta e&longs;t eius grauitas; hoc autem facilè percipiemus &longs;i &longs;ingamus duos homines æquè validos & robu&longs;tos qui totis viribus &longs;e mutuò impellant, vbi manife&longs;tum e&longs;t quòd exi&longs;tentibus vi­ribus contrarijs inter &longs;e æqualibus, vt vna alteri no&ntail; pr&ecedil;ualeat, tunc neuter luctantium dimouebitur è &longs;uo loco, &longs;ed ibidem quie&longs;cet, licèr quilibet corum vniuer­&longs;am vim, & facultatem propriam exerceat impellen­do, & repellendo &longs;uum antagoni&longs;tam, non &longs;ecùs quan­do aliquis impellit columnam ingentem vehemen­ter, licèt minimè valeat eam è &longs;uo loco deijcere, ac commouere, vt nimirum motus progre&longs;&longs;iuus hominis impellentis, aut columnæ &longs;ub&longs;equatur; nihilominùs negari non pote&longs;t motus impul&longs;iuus mu&longs;culorum, & artuum hominis impellentis; nec pariter negari po­te&longs;t aliqua exigua & in&longs;en&longs;ibilis flexio eiu&longs;dem colun­, quæ ad in&longs;tat arcus, &longs;eù machinæ æquali vi impul­&longs;ui, & flexioni re&longs;i&longs;tit. &longs;imiliter cùm pila ferrea &longs;uper ba&longs;im, vel laminam vitream innititur concedendum omninò e&longs;t effici con&longs;tipationem quamdam partium ferri prementis, & vitri compre&longs;&longs;i, vt nimirum ali­quanti&longs;per eorum poro&longs;itates con&longs;tringantur, eò quòd (vt o&longs;ten&longs;um e&longs;t cap. 26. de Vi percu&longs;&longs;ionis) reperiri in rerum natura corpora compo&longs;ita nequeunt quæ ad­eò dura &longs;int vt compre&longs;&longs;ioni cuiuslibet corporis re&longs;i­&longs;tere valeant. quod verò prædicta compre&longs;&longs;io vitri ab ingenti pondere &longs;iat patet ex eo quòd augendo ma­gis ac magis pondus comprimens, tandem ba&longs;is vi-trea di&longs;rumpitur, di&longs;&longs;ilit, atque conteritur eo pr&ecedil;cisè modo quo ab ictu mallei di&longs;rumpitur; & &longs;i quidem hoc verum non e&longs;&longs;et &longs;cilicèt &longs;i à pondere vtcumqu&etail; multiplicato & aucto ba&longs;is vitrea non &longs;tringeretur & comprimeretur, quælibet exili&longs;&longs;ima ba&longs;is vitrea to­leraret vim compre&longs;&longs;iuam ponderis cuiu&longs;libet montis va&longs;ti, quod procul dubio fal&longs;um e&longs;t.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Hoc po&longs;ito nemo negabit quòd &longs;i pondus duplice­tur vt &longs;cilicèt vnum &longs;uper alterum &longs;uperponatur, tunc duplici vi, ac robore infima ba&longs;is vitrea comprime­tur ac con&longs;tipabitur, & proindè poro&longs;itates multò magis imminuentur à duplici impul&longs;u, quando quidem concipi non pote&longs;t moles grauis aucta & multiplica­ta ab&longs;que eo quòd pondus, & proindè vis, & energia compre&longs;&longs;iua versùs centrum telluris multiplicetur, vnde fit vt partes &longs;olidæ & con&longs;i&longs;tentes comprimantur & con&longs;tipentur multo magis.

At &longs;i hoc contingit in corporibus duri&longs;&longs;imis, nega­ri certè non poterit in corporibus fluidis, quæ no&ntail; minùs grauia &longs;unt & com primunt fundum va&longs;is in quo continentur tanta vi, quanta e&longs;t energia ponderis eorum, ita ut multiplicata fluidi mole centies, & mil­lies va&longs;is fundum centies, & millies maiori vi com­primatur, & licèt ibidem non ad&longs;it motus progre&longs;­&longs;iuus, numquam tamen deficiet motus tonicus, & re&longs;­trictio pororum fundi va&longs;is, & compre&longs;&longs;io pororum eiu&longs;dem fluidi, &longs;i fortè poro&longs;itates habuerit, & &longs;icuti fluidum grauitat atque con&longs;tringit poro&longs;itates fundi va&longs;is, hac de cau&longs;a, quia ponderat, & grauitat, nulla ratio vetat, quin pondere &longs;uo comprimat in fimam &longs;u­biectam laminulam eiu&longs;dem fluidi quæ fundo va&longs;is contigua e&longs;t, quandoquidem minimè po&longs;&longs;unt &longs;upre­mæ fluidi partes fundum va&longs;is comprimere ab&longs;qu&etail; eo quod impellant, & &longs;tringant in fimam eiu&longs;dem flui­di laminulam, cùm actio in di&longs;tanti fierinon po&longs;&longs;it, &longs;ed contactu quodam remotiores impellendo eis conti­guas &longs;ubiectas partes, & hæ&longs;ub&longs;equentes &longs;erie qua­dam ordinata quou&longs;que fundum comprimant.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XIII.

Aqua va&longs;is fundum çomprimit &longs;ua grauitate.

SEd hoc euidentius &longs;ic patebit, &longs;it fi&longs;tula vitrea A NO perpendiculariter ad horizontem erect&atail;, repleaturquè aqua, &longs;eù quolibet alio fluido cor­pore, & ductis innumeris planis horizonti æquidi&longs;tan­tibus &longs;ubdiuidatur vniuer&longs;um fluidum i&ntail;

laminas gracillimas &longs;eù membranas æquè altas AB, BC, CD, DE, EF, FM, & MN. & primò &longs;i verum e&longs;t, vt aduer&longs;arij credunt aquam in ip&longs;amet aqua collocatam non gra­uitare, igitur &longs;uprema laminula aquea AB pror&longs;us non comprimet &longs;ubiectam membra­nam aqueam BC, &longs;cilicet vim nullam &longs;uper eam exer­cebit (hoc enim grauitatis nomen indicat) neque eam deor&longs;um impellet perinde ac &longs;i aqua &longs;uprema AB non ade&longs;&longs;et, proindeque hæc non augebit grauitatem in­ferioris laminæ BC, aliàs &longs;uprema aqua AB pondera-ret, comprimeretque &longs;ubiectam aquam BC, quod e&longs;t contra aduer&longs;arij hypothe&longs;im; eadem ratione vniuer­&longs;a aqua ABC nil ponderabit, ne que comprimet &longs;ub­iectam laminam aqueam CD, & tota aqua AD nec etiam comprimet aut grauitatem inferet &longs;upra infe­riorem aquam DE; idip&longs;um procul dubio aflirmari de­bet de reliquis omnibus laminulis fluidis totam alti­tudinem aquæ componentibus, & hoc optima ratio­ne de duximus, quando quidem &longs;eriem corporum iner­tium & nil pror&longs;us deor&longs;um impellentium nemo &longs;anæ mentis affirmabit vim compre&longs;&longs;iuam deorsùm exer­cere, imò concedet æquè operari ac &longs;i e&longs;&longs;et vnica &longs;in­gularis laminula, vel dicet &longs;ubiectum corpus à nihilo comprimi, & è contra &longs;eries corporum vim impul&longs;iuam habentium exercet vim pro men&longs;ura multiplicati cor­poris, & hoc &longs;anè lumine naturæ con&longs;tat, hinc deduci­tur infimam laminam aqueam MN no&longs;tri va&longs;is nullam compre&longs;&longs;ionem pati ab vniuer&longs;a aqua &longs;uperpo&longs;it&atail; MA non &longs;ecùs ac &longs;i à nihilo premeretur vnde fit vt in­ferior pars aquea MN ablata qua MA tanta vi præ­cisè comprimat va&longs;is fundum NO ac &longs;i &longs;uper&longs;taret immen&longs;a moles aquea NA, &longs;ed illa ob ponderis exi­guitatem haud &longs;en&longs;ibilem vim vitreo fundo infert, nec ip&longs;um inflectit, aut di&longs;rumpit, igitur neque vitrum inflectetur aut con&longs;tringetur quando alti&longs;&longs;ima moles a­quea NA ei &longs;uperponitur; quia verò hoc euidentiæ &longs;en&longs;us repugnat affirmandum e&longs;t, aquam licèt in ip&longs;a­met aqua iners & quie&longs;cens videatur, nece&longs;&longs;ariò gra­uitatem exercere.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens ponde­rat.

PROP. XIV.

Id ip&longs;um in &longs;iphone comprobatur.

PRæterea v&longs;urpetur idip&longs;um vas vitreum, &longs;ed in­flexum, vt e&longs;t AMOP &longs;iphonis inuer&longs;i figuram referens, atque portio ANO aqu&atail;

impleatur, reliqua verò fi&longs;tula OP o­leo. Et quia vt mox o&longs;ten&longs;um e&longs;t ex aduer&longs;arij hypothe&longs;i tota aqua AM vim non infert neque impellit infe­riorem aqueam laminam MN, cù&mtail; nullam grauitatem &longs;uper eam exer­ceat; igitur tota moles aquea AM nil prorsùs impel­let terminum aquæ O & proindè ab hoc non impelle­tur &longs;ur&longs;um oleo&longs;us cylinder OP, igitur oleum OP nulla ratione &longs;ubleuari &longs;ursùm deberet, &longs;ed hoc e&longs;t fal&longs;um, igitur fal&longs;a e&longs;t quoque hypothe&longs;is a&longs;&longs;umpta, quòd aqua in ip&longs;amet aqua po&longs;ita grauitatem no&ntail; exerceat.

Et profectò methodus ac criterium digno&longs;cendi, an corpus aliquod grauitet, atque impellat alterum, erit huiu&longs;modi; con&longs;iderari nimirum debent effectus ab eo producti, & quanta vis contraria requiritur, vt vnum à con&longs;ortio, & contactu alterius diuellatur, & &longs;eparetur, & quia &longs;i nauis natando lateraliter &longs;co­pulum contigeret, po&longs;&longs;et à quacumque exigua vi tra­hi, diuelli, & &longs;eparari ab eodem &longs;copulo, hinc in re optimo inferemus nauim omninò carere vi motiua, & impul&longs;iua tendendi ver&longs;us &longs;copulum, è contra, quia videmus, quòd pila ferrea non pote&longs;t à contactu &longs;oli &longs;eiungi, ac diuelli ni&longs;i æqualis facultas, & energi&atail; contraria adhibeatur, &longs;cilicet ni&longs;i apponatur pondus in altera extremitate libræ, quod æquale &longs;it grauita­ti prædictæ pilæ ferre&ecedil;, &longs;icuti cùm homo robu&longs;tus co­lumnam aliquam impellit, non pote&longs;t ab ea &longs;eiungi, ni&longs;i adhibeatur vis motiua prorsùs æqualis ei, quam homo exercet; hinc de ducemus pilam vim grauitatis, & hominem vim mu&longs;culorum exercere.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Porrò effectus producti ab illa ferrea pila à paui­mento &longs;ubnixa plures &longs;unt, ac varij, con&longs;tringuntur nempè pori &longs;ubiecti corporis pilam &longs;u&longs;tinentis, in­flectitur paritèr idip&longs;um contunditurque, & multo­tiès diffringitur, ac di&longs;&longs;ilit in particulas minimas, igitur &longs;i huiu&longs;modi effectus ip&longs;amet aqua operaretur, ab&longs;que vlla hæ&longs;itatione aquam in ip&longs;amet aqua gra­uitare affirmaremus. Modò videmus, quòd aqua ad ingentem altitudinem eleuata nedùm &longs;olum, ac fun­dum va&longs;is inflectit, &longs;ed ip&longs;um multoties diffringit, & hoc magis patet &longs;i fundum va&longs;is flexibile fuerit, &longs;i ve­rò con&longs;tringi, ac conden&longs;ari poterit, illud con&longs;trin­git, atque ad minus &longs;patium redigit, non &longs;ecùs ac homo robu&longs;tus comprimeret, & &longs;lecteret corpor&atail; flexibilia, ac cedentia, dum ea impelleret.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XV.

Alia ratione, & experimento probare compres&longs;ionem par­tium aquæ, & rerum in ea contentarum à pon­dere ip&longs;iu&longs;met aquæ.

SIt fi&longs;tula vitrea RVX vndique clau&longs;a præterquam in &longs;upremo orificio R, hæc verò aqua repleatur, & in ea ampullula vitrea AD immerga­

tur &longs;itque ea plena aere, & eius pars ver­&longs;us infimum orificium a pertum D graui­or &longs;it, ad hoc vt ampullula AD &longs;emper inuer&longs;o &longs;itu in ip&longs;a aqua per&longs;i&longs;tat. in hac machina ob&longs;eruatur quòd vexica vitrea AD quò magis deprimitur infra &longs;upre­mam aquæ libellam, vel potiùs ip&longs;amet aqua altiùs infunditur, & eleuatur, tune eò magis aer in ampulla contentus con­den&longs;atur, atque in minori &longs;patio con&longs;trin­gitur, & hoc fen&longs;u ip&longs;o patet dum aqu&atail; ingreditur per orificium D atque colli ampullæ particulam aliquam implet; quod verò hu­iu&longs;modi aeris re&longs;trictio &longs;it effectus ponderis aquæ &longs;u­premæ comprimentis &longs;en&longs;u ip&longs;o digno&longs;citur, nam quò magis aquæ &longs;uprema &longs;uperficies S eleuatur versùs R &longs;emper magis, ac magis &longs;ucce&longs;&longs;iuè aeris moles præ­dicti tubuli con&longs;tringitur &longs;ubintrando nimirùm aqua magis à C versùs B. Quòd verò hoc dependeat à con­pre&longs;&longs;ione multiplicati ponderis aquæ &longs;ubleuatæ alià clariori experientia percipitur, &longs;i enim ab&longs;que noua aquæ in fu&longs;ione in fi&longs;tula aliqua breui, vel pollice, vel &longs;ubere comprimatur aqua orificium R attingens &longs;ta­tìm apparet effectus prædictæ compre&longs;&longs;ionis aquæ, conden&longs;atur enim, ac&longs;tringitur aer in vitrea ampul­la AD eodem modo præcisè, ac maior mo­
les altioris aquæ eleuatæ faciebat, e&longs;tqu&etail; huiu&longs;modi compre&longs;&longs;io acris in prædict&atail; ampullula tantæ energiæ vt exi&longs;tente eale­ui, &longs;cilicet quæ &longs;ponte &longs;ua &longs;ur&longs;um in aqu&atail; SX a&longs;cendat po&longs;&longs;it è contrà leuitatem amit­tere, atque acquirere grauitatem, moueri­que, ac de&longs;cendere deor&longs;um, quotie&longs;cumque aqua in fi&longs;tula ad tantam altitudinem ele­uetur vt valdè comprimere ampullulæ aerem po&longs;&longs;it, vt eam grauem reddat, nec vt hactenùs &longs;ursùm, &longs;ed deorsùm vergat de&longs;cend atque.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XVI.

Alia ratione grauit atem aquæ &longs;uper aquam quie&longs;centis demon&longs;trare.

HOc deducitur ex eo quòd corpora, quæ ob ex­cedentem eorum grauitatem demerguntur in­fra aquam minùs grauitant in ip&longs;a aqua, quàm i&ntail; aere, vt &longs;i fuerit pila AB ferrea &longs;pecie grauior quàm &longs;it aqua ip&longs;a in va&longs;e RO contenta, & concipiatur IK vt pondus ab&longs;olutum pilæ ferreæ AB, &longs;cilicèt expri­mat eam grauitatem quam in aere exercet, &longs;it que eius portio K grauitas ab&longs;oluta pilæ aqueæ C quæ æqua­lis &longs;it ip&longs;i AB, &longs;it que pila C contenta intra eiu&longs;de&mtail; aquæ RO profunditatem, vel in altera fi&longs;tula inuer&longs;i &longs;iphonis, quæ cum reliqua continuetur, po&longs;tea eadem pila AB filo DA ab aliqua potentia I &longs;u&longs;pen&longs;a in me­dio aquæ fixè retineatur. modò &longs;i po&longs;&longs;ibile e&longs;t pil&atail; aquea C nil prorsùs ponderet in ip&longs;amet aqua, igitur in &longs;iphone, vel in libra DE in eius puncto medio F fulta pila aquea C &longs;u &longs;pen&longs;a à termino E, quæ nullam pror&longs;us granitatem exercere in aqua &longs;upponitur, nun­quam imminuet pondus contrapo&longs;itæ pilæ AB colli­gatætermino libræ D, propterea quòd nihilum ab aliquo pondere &longs;ubtractum ip&longs;um nullo pacto immi­nuit; nec pariter denfitas, & tenacitas aquæ gradum ponderis pilæ AB diminuere pote&longs;t, propterea quòd illa re&longs;i&longs;tentia potis e&longs;t retardare, & impedire mo­tum, non autem vim, quam graue AB in quiete con­&longs;titutum exercet comprimendo; videmus enim, quòd pila ferrea quie&longs;cens &longs;iue fulciatur à mollicera, &longs;iue à rigido adamante, &longs;emper eadem vi comprimit, &longs;ci­licetmen&longs;urata à gradu eius ponderis.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

His po&longs;itis &longs;equitur, quòd pila fer­rea AB pendula intra aquam exerce­bit integram &longs;uam grauitatem IK, &longs;cilicet eam, quam in aere exerce­bat, &longs;ed hoc e&longs;t fal&longs;um, imminuitar enim præcisè pro men&longs;ura ponderis K &longs;cilicet molis aqueæ C, & ei relin­quitur tantummodò pondus I, &longs;cili-cet exce&longs;&longs;us quo pondus eius ab&longs;olutum &longs;uperat gra­uitatem aquæ eiu&longs;dem molis; quapropter verum non e&longs;t aquam C in ip&longs;amet aqua con&longs;titutam, nullam con­pre&longs;&longs;ionem, aut grauitatem exercere.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens ponde­rat.

PROP. XVII.

Idip&longs;um alia ratione demon&longs;trare.

VAs RO repleatur aqua, in eaque immergatur pila ferrea BA quæ filo aliquo DA &longs;u&longs;tineatur ne ad fundum va&longs;is de&longs;cendat. Manife&longs;tum e&longs;t poten­tiam D filum, & pilam retinentem æquari ei graui­tati quam ip&longs;a pila in aqua exercet, & quia in va&longs;e aqueo RO deficit præcisè tanta aquæ quantitas, quan­tum e&longs;t &longs;patium, quod corpus graue A in ip&longs;a oc­cupat, collocatur verò intra aquam ne dum grau&etail; AB, &longs;ed etiam defectus molis aquæ æqualis eide&mtail; AB quare &longs;umma po&longs;itiu&ecedil; grauitatis AB vnà cum de­fectiuo pondere molis aquæ expul&longs;æ à loco AB, &longs;ci­licet exce&longs;&longs;us ponderis AB &longs;upra pondus molis aquæ æqualis pilæ AB æqualis erit ponderi quod exercet pila AB in aqua ergò &longs;i huiu&longs;modi aquæ moles ex &longs;ui natura nil in aqua ponderat quando tollitur a &longs;patio AB moles aquea, quæ ip&longs;um replebat reuerà tollitur res non grauis, & quæ nil omninò ponderat; igitur à pondere ab&longs;oluto ip&longs;ius AB, & à &longs;patio ab ea occu­pato nihilum, &longs;eù nulla grauitas &longs;ubtrahitur, quando verò ab ab&longs;oluta grauitate IK pilæ AB nil pror&longs;us tollitur, remanet eiu&longs;dem gradus, ac proindè pon-dus pilæ AB nil prorsùs imminutum erit, & æquali energia &longs;u&longs;tineri debet à potentia D, ac &longs;i eadem pi­la extra aquam in aere libero penderet, &longs;ed hoc e&longs;t fal&longs;um, cùm præcisè in ip&longs;a aqua grauitas pilæ æqua­lis &longs;it differentiæ ponderis eius ab&longs;oluti à grauitat&etail; aquæ &longs;ibi æqualis mole, vt ex Archimede deducitur, igitur nece&longs;&longs;ariò fatendum e&longs;t aquam in ip&longs;amet aqua collocatam ponderare, & grauitatem exercere.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Contra hoc euidenti&longs;&longs;imum ratiocinium afferri &longs;olet difficultas valdè &longs;pecio&longs;a, quam examinare, ac di&longs;&longs;oluere erit operæ pretium, vtque ea ritè percipi­atur, con&longs;ideretur hæc figura. Sit vas cylindricu&mtail; ABDC aqua plenum &longs;it que eius altitudo

di&longs;&longs;ecta in quotcumque partes æquales, ductis nempè planis imaginarijs MO, & HI, erit igitur moles aquea AI dupl&atail; aque &ecedil; molis HD; igitur pondus aquæ AI duplum e&longs;t ponderis aquæ HD. quia ve­rò corpus grauius minùs graue &longs;uperare debet, hocque è &longs;uo loco expellere (cùm in eo con&longs;i­&longs;tat vis, & energìa grauitatis, vt tendat deorsùm, & &longs;ic è loco infimo corpora minùs grauia expellat) & po&longs;tquàm aqua AI translata e&longs;t ad locum HD, atque aquam ibidem collocatam expulit denuò in &longs;itu &longs;u­periori fi&longs;tulæ AI aqua dupli ponderis, & molis ibi­dem re&longs;tituitur quæ pariter &longs;uperat grauitatem &longs;ub­duplam aquæ, quæ ad occupandum infimum locum HD &longs;ucce&longs;&longs;it, igitur denuò aqua &longs;uprema vt grauior in&longs;imam è &longs;uo loco extrudere, atque expellere de-bet, & quia hoc &longs;emper repetitur, &longs;cilicèt perpetuò re&longs;tituitur in &longs;uperioriloco AI aqua duplò grauior, quàm ea, quæ in loco infimo HD reponitur, igitur vt contingit in libra efficientur perpetuæ, & conti­nuatæ vibrationes, veluti in pendulo, & in aqua fie­ri&longs;olent plures vndulationes, &longs;ic in aqua perpetuo motu agitarentur eius partes a&longs;cendendo, & de&longs;cen­dendo. hoc verò &longs;en&longs;us euidentia redarguit, igitur fatendum e&longs;t &longs;upremam aquam AI &longs;u&longs;tentatam ab inferiori aqua &longs;uper eam non exercere vim vlla&mtail;, nec pre&longs;&longs;ionem, proinde que non grauitare, hac &longs;cili­cet de cau&longs;a, quia nimirùm in eius loco naturali col­locatare quie&longs;cit, ac &longs;i&longs;titur.

Contra do­ctrinam &longs;u­periùs addu­ctam ade&longs;t noua difficul­tas, quod ni­mirum mo­tu perpetuo aqua agitari deberet.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens ponde­rat.

PROP. XVIII.

Maior aquæ moles alteri &longs;upe po&longs;ita non exercet maiorem vim compres&longs;iuam, quàm minor.

VT verò huiu&longs;modi paralogi&longs;mus detegatur, a­nima duertend um e&longs;t minimè verum e&longs;&longs;e, quòd quælibet aquæ moles maior alterà, nempe dupla, exer­ceat quoque duplam vim grauitantem quotie&longs;cum­que maior &longs;upra minorem in&longs;i&longs;tat, & ab ea fulciatur, &longs;ed tunc &longs;olummodò propo&longs;itio verificatur quando earum ba&longs;es contiguæ æquales fuerint, ac in&longs;uper in eodem plano horizonti parallelo con&longs;titerint. Sup­ponatur vas cylindricum plenum aqua ABDC, &longs;it­que portio &longs;uprema, & ideò eius altitudo AH dupla infimæ altitudinis HB, licèt ergo reuerà &longs;upremæ aquæ AI pondus duplum &longs;it ponderis infimæ aquæ HD, non hìnc tamen inferri licet &longs;ubiectam aquam HD in tali &longs;itu vnicam libram tantummodò pendere exi&longs;tente &longs;upremo pondere AI duarum librarum, &longs;ed nece&longs;sè e&longs;t vt aqua HD comprimat va&longs;is fundum BD ni&longs;u, ac vi non vnius libræ, &longs;ed æquali ei, quæ effi­citur à pondere trium librarum, & ratio e&longs;t quia ip­&longs;a aqua HD nedùm impellitur deor&longs;um à vi propriæ grauitatis vnius libræ, &longs;ed in&longs;uper grauatur compri­miturque ab incumbente pondere aquæ AI, quæ com­pre&longs;&longs;io &longs;uperaddit aqu&ecedil; HD vim æqualem ei, quæ à duabus libris effici pote&longs;t; nec profectò nouum e&longs;t &longs;i­quis centum laminas ferreas, vellapideas, æquè pon­derantes, &longs;cilicet &longs;ingulas vnius libræ vnam &longs;uper al­teram imponat, quod in&longs;ima lamina non tantummo­dò &longs;uo pondere comprimet planum &longs;ubiectum, &longs;cili­cèt non efficiet vim æqualem cente&longs;imæ parti totius prædicti aggregati, &longs;ed compre&longs;&longs;io infim&ecedil; laminæ ef­ficiet vim centuplo maiorem &longs;cilicèt impellet &longs;ubie­ctum planum vi æquali centum libris, & tunc &longs;olum­modò in&longs;ima lamina partem cente&longs;imam totius ag­gregati ponderabit, quando illa in vna lance, reli­quæ verò 100. in oppo&longs;ita lance eiu&longs;dem libræ ra­diorum æqualium &longs;u&longs;penderentur; &longs;ic paritèr &longs;i aqua HD &longs;upra planum &longs;ubiectum &longs;iuè &longs;olidum, &longs;iuè flui­dum collocaretur iuxtà portionem aquæ AI, itaut &longs;e­&longs;e contingerent lateraliter, atque earum ba&longs;es æqua­les in eodem plano horizontali collocarentur, tunc nece&longs;&longs;ariò dupla moles aquæ AI duplam vim com-pre&longs;&longs;iuam, pro men&longs;ura duplæ grauitatis haberet. Verum tamen e&longs;t, quòd alia de cau&longs;a non e&longs;t nece&longs;­sè, vt &longs;emper ba&longs;es &longs;int æquales, neque grauitates &longs;int in eadem proportione dupla, dummodò altitu­do AH dupla &longs;it altitudinis ip&longs;ius HB; & ratio huius diuer&longs;itatis pendet ex alibi demon&longs;trandis.

Cap. 3. flui­dum in &longs;ue toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens ponde­rat.

Ex &longs;uperiori igitur ratiocinio euinci­

tur, fal&longs;um e&longs;&longs;e, quòd pronunciabatur, nimirùm, duplam aquam AI vt grauio­rem, expellere de&longs;cendendo debere &longs;ub­duplam aquam &longs;ubiectam HD, cùm ècon tra hæc vt grauior, grauitate nempe pro­pria, & ea, quæ ei &longs;uperadditur ab aqua &longs;uperincumbente AI in eodem loco infimo perma­nere debeat, nec vnquam à debiliori compre&longs;&longs;ione &longs;uper&longs;tantis aquæ expelli po&longs;&longs;it, ac proindè &longs;equitur &longs;umma quies, ac tranquillitas, non verò motus per­petuus.

Ex doctrina &longs;uperiùs tra­dita videtur deduci po&longs;­&longs;e lignum infra aquam po&longs;itum &longs;ur­&longs;um a&longs;cende­re non po&longs;&longs;e.

Sed dices, &longs;i vera e&longs;&longs;et adducta doctrina, lignum deberet in fundo aquæ paritèr retineri, proptere&atail; quòd nedum à propria grauitate comprimitur, &longs;ed etiam à pondere totius aquæ &longs;uper&longs;tantis, & ideò magis grauitaret quàm aqua ei&longs;uperpo&longs;ita, & proin­de lignum in fundo aquæ permanere deberet: hoc autem fal&longs;um e&longs;t, cùm experientia con&longs;tet, lignum &longs;ursùm ferri, nec quie&longs;cere, antequàm ad aquæ &longs;u­premam libellam perducatur.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XIX.

Lignum infra aquam demer&longs;um, licèt pondus proprium, & aquæ incumbentis exerceat, non proinde ibidem quie&longs;cet.

VT autem huius argumenti falla cia pate&longs;iat, in va&longs;e ARSE aqua pleno demergatur pri&longs;ma li­gneum, vel aereum HBDI &longs;itqu&etail;

pondus aquæ AI decem libraru&mtail; v. g. lignum verò HD &longs;emilibra&mtail; pendeat. Concedo, quòd lignu&mtail; HD premit &longs;ubiectam aquam BV non vi&longs;emilibræ, &longs;edrobore libra­rum decem, & &longs;emis, & ideo lignum HD magis comprimit, ac grauitat, quàm &longs;ola aqua incumbens AI, &longs;ed non proindè &longs;e­quitur, lignum HD quatenùs magis comprimit, ac grauitat in fundo aquæ per&longs;i&longs;tere debere, cùm ab alia cau&longs;a &longs;ursùm exprimatur. Secto enim pri&longs;mat&etail; aqueo CEFI æquali ip&longs;i AI, & aqueo pri&longs;mate IG cuius moles æqualis &longs;it ligno HD, & eius pondus duas libras &longs;uperet; patet quòd aqua &longs;ubiecta BV premitur à pondere librarum decem, & &longs;emis, at aqua DS comprimitur à pondere librarum duode­cim; ergo sipho, vellibra mobilis aquea BG flecti debet eleuando lignum HD minus graue. Et hinc patet, quòd ratio, quare lignum a&longs;cendit, non e&longs;t pondus aquæ incumbentis AI, &longs;ed e&longs;t aqua collate-ralis IG, & hoc con&longs;tat, quia &longs;i in &longs;tricta fi&longs;tula vitrea ARVC ponatur in eius fundo aqua BV in loco me­dio lignum HD, vel exigua aeris ve&longs;ica, quæ va&longs;is latera exactè tangat, & reliquum va&longs;is repleatur a­qua AI, tunc lignum non a&longs;cen det &longs;ur&longs;um, quia nem­pè &longs;ipho, vel libra mobilis cum aqua collaterali crea­rinon pote&longs;t.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

CAP. XX.

Corpora terrena cùm è locis &longs;uis naturalibus remouentur de&longs;cendendo nullam grauitatem exercent.

SEd &longs;ublata prædicta difficultate deuenio ad o&longs;ten­dendum quòd adeò fal&longs;um e&longs;t corpora terrena dum quie&longs;cunt in proprijs locis non grauitare, vt è contra quando à locis naturalibus &longs;eparata mouen­tur tunc nullam grauitatem exerceant &longs;u per alias par­tes eiu&longs;dem corporis, quod licèt videatur parado­xum, o&longs;tendetur nihilominùs hac ratione. Conci­piantur primò facilitatis gratia duo lanæ inuolucra, vnum &longs;uper alterum impo&longs;itum &longs;upra planum &longs;ubie­ctum, certum e&longs;t &longs;upremum comprimere, & grauita­tem exercere &longs;upra &longs;ubiectum inuolucrum, & hoc con­&longs;tat &longs;en&longs;u ab effectu ouem producit pondus lanæ in­cumbentis, &longs;cilicèt ex inflexione, & compre&longs;&longs;ion&etail; pilorum &longs;ubiectæ lanæ, & è contra con&longs;tat quando eadem duo lanæ inuolucra collateralitèr &longs;e&longs;e contin­gunt fulciunturque à &longs;ubiecto plano, tunc neque pi­li lanei collaterales inflectuntur, nec comprimuntur, propterea quòd ni&longs;us grauitatis non exercetur late­raliter, &longs;ed deorsùm.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Hinc colligitur, quòd quotie&longs;cumque &longs;upremum lanæ inuolucrum perpendicularitèt incumbens &longs;u­peralterum, &longs;i ip&longs;um non flecteret, nec &longs;tringeret, tunc planè affirmandum e&longs;&longs;et lanam &longs;uperpo&longs;ita&mtail; minimè &longs;uper &longs;ubiectam lanam grauitatem exercere.

His po&longs;itis, &longs;upremum lanæ inuolucrum applica­ri pote&longs;t &longs;uper infimum dum hoc actu per aerem mo­uetur de&longs;cendendo deor&longs;um, vel dum quie&longs;cit à pla­no &longs;tabili fultum; in primo ca&longs;u manife&longs;tum e&longs;t, quòd inuolucra æqualia eiu&longs;dem lanæ æquales gra­dus velocitatum habent, quibus naturaliter de&longs;cen­dunt; igitur &longs;upremum inuolucrum non de&longs;cendet tardiori, vel celeriori motu quàm &longs;ibi &longs;ubiectum, pro­indeque æquali velocitare &longs;uprema lana compri­mere conatur &longs;ubiectam lanam, ac i&longs;ta nititur effu­gere per&longs;equentem; proptereaque &longs;e mutuo placi­do contactu &longs;olummodò exo&longs;culantur, nec &longs;ubiecta inflectetur, aut comprimetur à &longs;uper&longs;tante lana: igitur, ex &longs;uperiùs dictis incumbens lana nequè pon­dus, neque grauitatem exercebit &longs;upra fugientem lanam &longs;ubiectam. In &longs;ecundo verò ca&longs;u &longs;i po&longs;tquàm in quiete &longs;ubiecta lana compre&longs;&longs;a e&longs;t à &longs;uperincum­bente ambas demittamus, & liberè deor&longs;um de&longs;cen­dere concedamus, patete as motum inchoare quan­do iam re&longs;trictæ, & con&longs;tipatæ &longs;unt, & ideò in pro­gre&longs;&longs;u licèt paribus velocitatibus de&longs;cendant, reti­ne bunt tamen eandem con&longs;tipationem, quam prius habebant; &longs;ed hinc non licet inferre, &longs;upremam la­nam dum mouetur grauitatem exercere, quia ill&atail; con&longs;tipatio non dependet ab actione grauitatis in­cumbentis lanæ quæactio per&longs;eueret exerceaturque tempore de&longs;cen&longs;us, &longs;ed illa con&longs;tipatio e&longs;t effectus compre&longs;&longs;ionis in præcedenti quiete factæ, in actu e­nim de&longs;cen&longs;us nullo pacto impellere pote&longs;t &longs;uprema lana &longs;u biectam pani velocitate ictum fugientem, & ideo &longs;u per eam minimè pondus exercebit.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens ponde­rat.

PROP. XXI.

Aqua de&longs;cendens per aerem, nullam grauitatem habet, & &longs;olummodò eam exercet, quando quie&longs;cit &longs;uper aquam.

SImili modo aqua non de&longs;cendit, quando fulci­tur à &longs;uper&longs;icie terræ, & maris, &longs;ed quando extra &longs;uum locum peregrinatur, & mouetur, vt i&ntail; aere, & tunc &longs;i con&longs;ideretur cylindrus aqueus per ae­rem de&longs;cendens, diuidaturque in partes æquales à planis horizonti æquidi&longs;tantibus; quia partes æqua­les eiu&longs;dem aquæ &longs;unt æquè graues, habent impe­tus æquales à natura &longs;ibi a&longs;&longs;ignatos quibus de&longs;cen­dere deor&longs;um nituntur, igitur pars &longs;uprema ciu&longs;dem cylindri aquei æquè velox erit, ac pars ei &longs;ubiecta, igitur &longs;uprema non poterit impellere, vel compri­mere aquam ei &longs;ubiectam, cùm æquali velocitat&etail; h&ecedil;c ictum, & percu&longs;&longs;ionem fugiat cum quanta à &longs;u­perincumbente in&longs;ectatur per&longs;equiturque, &longs;icuti &longs;agitta explo&longs;a minimè percutiet &longs;ignum æquali ve­locitate ictum fugiens; igitur manife&longs;tum e&longs;t, aquam minimè grauitatem exercere &longs;upra ei &longs;ubiectam a­quam, quando à proprio loco naturali exulat, & per aerem mouetur.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Secùs autem contingit in aqua quie&longs;cente, i&ntail; puteo aliquo, vellacu, &longs;i enim diuidatur pariter in laminas æque altas, patet quòd &longs;upremane dum tan­git &longs;impliciter &longs;ubiectam aquæ laminam, &longs;ed è con­tra eam impellit tanta vi quanta e&longs;t energia eius gra­uitatis, & patet quòd infima aqua pati cogitur com­pre&longs;&longs;ionem, cùm &longs;u&longs;tinere debeat pondus &longs;upremæ aquæ incumbentis: & hoc accidit, quia &longs;ua quiete impedit progre&longs;&longs;um, & conatum compre&longs;&longs;iuum de­orsum &longs;u perpo&longs;itæ aqu&ecedil;; hac de cau&longs;a &longs;i habue it poro­&longs;itates hæ nece&longs;&longs;ario con&longs;tringentur à vi ponderis incumbentis aquæ. Modò quia impul&longs;us compre&longs;&longs;i­uus factus à &longs;uperiore aqua &longs;upra inferiorem nullo alio vocabulo de&longs;ignatur, quàm grauitatis, vel pon­deris, igitur verum erit, quòd aqua &longs;uper aquam quie&longs;centem grauitatem exercet non quando in mo­tu con&longs;tituitur, & extra &longs;uum naturalem locum, &longs;ed, tantummodò, quando &longs;i&longs;titur, & quie&longs;cit in loco &longs;uo naturali.

Contra do­ctrinam &longs;u­p: riùs addu­ctam afferri &longs;olet difficul tas valdè plau&longs;ibilis, quod nimi­rum vrina­tores ingens pondus aque incumbentis nec patian­tur, nec &longs;en­tiant.

Hi&longs;ce omnibus rationibus opponi&longs;olet experien­tia &longs;atis vulgata, e&longs;tque huiu&longs;modi: vrinatores i&ntail; profundo maris demer&longs;i non &longs;entiunt, neque patiun­tur compre&longs;&longs;ionem &longs;uperincumbentis aquæ, quæ multoties plures congios excedit; hinc inferunt, &longs;i aqua in ip&longs;amet aqua pondus, & grauitatem habe­ret, nece&longs;&longs;ariò vrinatores comprimerentur à va&longs;to pondere aquæ incumbentis &longs;uper eorum humeros, immò nec po&longs;&longs;et pondus tam va&longs;tum à viribus huma­nis &longs;u&longs;tineri, quando videmus, ab homine robu&longs;to minus pondus &longs;u&longs;tineri non po&longs;&longs;e; cùm ergo experi­entia doceat vrinatores in fundo aquæ grauitate&mtail; nullam percipere, igitur verum non e&longs;t, aquam i&ntail; ip&longs;a aqua collocatam grauitare, immò in proprio lo­co nil prorsùs ponderahit.

Cap. 3. flui dum in &longs;uo toto quie­&longs;cens ponde­rat.

Huic vulgari difficultati vt fiat &longs;atis præmittendum e&longs;t, quòd aqua in ip&longs;amet aqua con&longs;tituta, pariterque quodlibet fluidum in &longs;uo homogeneo demer&longs;um non alia de cau&longs;a quie&longs;cit, ni&longs;i quia vndique comprimi­tur pari vi à grauitate ambientis fluidi, cui propri&atail; grauitate re&longs;i&longs;tit, vtque hoc clariùs percipiatur, o­&longs;tendemus, quod.

PROP. XXII.

Corpora in bilance æquilibrata ideò quie&longs;cunt, & torpent, quia grauitatem exercent comprimunturque æquali­bus viribus ab ambientibus corporibus pariter æquilibratis.

ESto libra AB radiorum æqualium in eius puncto intermedio C &longs;u&longs;pen&longs;a, atque in eius extremi­tatibus, vtrinque quatuor laminas, vellateres æquè ponderantes &longs;ibi mutuò incumbentes apponantur, &longs;cilicet DE, EF,, FG, GH, &longs;u per A, & totidem IK, KL, LM, MN &longs;uper terminum B. Manife&longs;tum e&longs;t, ag­gregatum ex laminis DH ibidèm retineri indifferen­tia quadam, nec pelli &longs;ursùm, aut deorsùm, firmiter­que in tali &longs;itu quie&longs;cere, vt nimirùm &longs;i quis infr&atail; laterem DE manum &longs;upponeret, minimè ab ip&longs;is con­primeretur, neque vllam grauitatem perciperet, hoc autem non contingit ex eo, quòd lamin&ecedil; lateritiæ grauitatem amittant, & deorsùm nil comprimant, &longs;ed quia ab æquali vi contraria &longs;u&longs;tinentur, ac &longs;ursùm impelluntur à pondere nempè oppo&longs;ito IN &longs;ibi æquali in libra AB premente. Præterea quælibet lamina in­termedia FE &longs;imilitèr quie&longs;cit, &longs;i&longs;titurque iners, vt ncque &longs;ursùm, neque deorsùm moueatur, nequ&etail; &longs;ubiectam manum, quæ lateralitèr eam retinere co­naretur vllatenùs comprimit, aut impellit, & hoc efficitur quia lamina

FE comprimitur de­or&longs;um ab incumben­te pondere FH, &longs;ur­sùm verò impellitur à &longs;ubiecta lamina DE non virtute propria, &longs;ed eius, quam exercet contra po&longs;itum pondus IN &longs;cilicet tan­ta vi, quanta pondus IN &longs;uperat pondus DE; &longs;ed quia præterea lamina ip&longs;a FE exercet vim &longs;ui ponderis contra pre&longs;&longs;ionem contrapo&longs;iti exce&longs;&longs;us KN fit vt vis quæ impellit &longs;ursùm laminam FE æqualis &longs;it exce&longs;&longs;ui ip&longs;ius KN &longs;upra FE, &longs;cilicet æqualis &longs;it NL; &longs;untque FH, & LN inter &longs;e æquales; ergo viribus æqualibus FE deprimitur ac &longs;ursùm impellitur. E contra lami-na FE impellit deor&longs;um laminam DE, ne dum pro­prio pondere, &longs;ed etiam grauitate laminarum FH; pariterque FE repellit laminas &longs;upremas FH no&ntail; propria virtute, &longs;ed vi ponderis LN &longs;cilicet exce&longs;&longs;u IN &longs;upra DF; Quaproptèr con&longs;tat, quòd lamina la­teritia FE comprimitur &longs;upernè, & infernè à duabus viribus contrarijs quæ æqualibus momentis operan­tur, à quibus proindè retinetur fixè, vt nequeat &longs;ur­sùm, aut deorsùm moueri. Præterea colligitur, quòd reuerà lamina lateritia FE non verè in quiete inerti con&longs;tituitur, nec pondere priuatur, &longs;ed potiùs effi­citur lucta quædam contrariarum virtutum æqualium virium, vndè æquatis momentis motus tonicus, &longs;eù quies &longs;ub&longs;equitur, & hìnc deducitur quòd prædicta corpora &longs;e mutuò comprimunt, & hìnc fit, vt neuter contrariorum impellentium &longs;uum iter pro&longs;equi valeat, proindeque cogantur fixè in eodem &longs;itu quie&longs;cere.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;ue­toto quie­&longs;cens pon­derat.

PROP. XXIII.

Idip&longs;um in aqua o&longs;tenditur exemplo &longs;iphonis.

EOdem ferè modo in aqua idem æquilibrium ef­fici manife&longs;tum e&longs;t, proindeque partes ip&longs;ius aquæ partim &longs;upernè comprimi à &longs;uper&longs;tantibus a­quæ partibus, partim verò infernè &longs;ursùm expelli, non propria vi, &longs;ed pondere collateralis aquæ, quæ cum illa libram imaginariam, vel &longs;iphonem con&longs;tituit. E&longs;to igitur, claritatis gratia, &longs;ipho HAB perpendi­cularitèr eleuatus &longs;upra horizontem, repletu&longs;qu&etail; aqua v&longs;que ad &longs;uprema orificia H & N; &longs;ubdinida­tur tota eius altitudo in partes æquales ductis nimi­rum planis &longs;uperficiebus GM,

FL, EK, DI; hic profectò aquæ portio FE, licèt nullum effectum grauitatis producere, atque iner­ter quie&longs;cere videatur, dùm in­differens e&longs;t ad motum fursùm, & deorsùm, non hìnc deducere licet, aquam ip&longs;am FE in tali &longs;i­tu vim propriæ grauitatis non exercere, nec comprimi ab aqua &longs;uperna, & inferna: con&longs;ideretur enim quòd FF, in parte &longs;uprema ab aqua FH comprimitur de­orsùm, è contrà à &longs;ubiecta aqua DE expellitur &longs;ur­sùm, non propria vi, &longs;ed pondere contrapo&longs;it&ecedil; aquæ NL. Hinc colligitur, quòd aqua FE reuerà impelli­tur deorsùm à &longs;uperna aqua, & &longs;ursùm ab inferna; ip&longs;a veròmet aqua FE è contrà vim exercet contr&atail; vtramque compre&longs;&longs;ionem, &longs;cilicèt contra eam, quæ efficitur ab aqua &longs;ubiecta, re&longs;i&longs;tit pondere &longs;uo pro­prio vnà cum grauitate incumbentis aquæ FH, &longs;ed contra vim, qua comprimitur &longs;upernè non re&longs;i&longs;tit, & contranititur virtute propria, &longs;ed mediante impul­&longs;u de&longs;cen&longs;iuo collateralis aquæ NK, igitur huiu&longs;mo­di quies aquæ, quæ in &longs;itu FE indifferentèr retinetur, nec pote&longs;t &longs;ursùm, aut deorsùm moueri, e&longs;t effectus, qui nece&longs;&longs;ariò con&longs;equitur ad exercitium &longs;uæ natiuæ grauitatis, & eius, quæ exercetur ab aqua &longs;iphonis, velab aqua collaterali eiu&longs;dem va&longs;is, in quo paritèr aqua operatur, veluti in &longs;iphone collocata fui&longs;&longs;et.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XXIV.

Aqua in ip&longs;amet aqua demer&longs;a undiquè comprimitur ab ambiente aqua, & vtraque grauitatem exercet.

INtra vas ABCD aqua plenum intelligatur pri&longs;ma aqueum FGHE, ducti&longs;que planis FL, & GM pa­rallelis horizonti. Dico, quòd aqua FH vndique pre­mitur ab ambiente aqua FILKG, & vtraque pondus grauitatemque exercet. Quia aqua FH cum aqu&atail; ambiente &longs;iphonem AKD con&longs;tituit, in quo fluidum &longs;ibi homogeneum agitari pote&longs;t, & quie&longs;cit nihilo­minùs; ergo vna pars fluidi AK

æquilibratur, proindequè æquè ponderat, ac pars reliqua latera­lis IC, portio verò aquæ FH licèt motu careat, &longs;itque indifferens ad motum &longs;ursùm, & deorsùm, haud inferre licet eam non exer­cere vim &longs;uæ grauitatis vnà cum tota aqua ambi­ente, quia in &longs;iphonis brachio AK aquæ FH &longs;u­prema facies FE deor&longs;um impelli, & comprimi de­bet ab incumbente aqua AE, pariterque infim&atail; illius facies GH &longs;ursùm impelletur à &longs;ubiecta a­qua GK non virtute propria, &longs;ed eius quam exercet pondus aquæ collateralis IM; porrò nedum aqua FH impellitur &longs;ur&longs;um ab aqua &longs;ubiecta BH, &longs;ed etiam, vt experientia con&longs;tat, impul&longs;ionem, & con&longs;trictionem patietur facies eius FH ab aqua collaterali DH; quod euidentius o&longs;tendetur prop. 192. Stringitur er­go aqua FH vcluti prælo, nec tamen iners omninò e&longs;t, repellit enim &longs;ursùm aquam
AE vi grauitatis aquæ lateralis IL, aquam verò &longs;ubiectam repel­lit deorsùm vi grauitatis pro­priæ, & &longs;upremæ IE. quare quies aquæ FH e&longs;t effectus dependens à compre&longs;&longs;ione facta ab aqua am­biente, & ab exercitio &longs;uæ grauitatis, & eius quam aqua ambiens &longs;iphonem con&longs;tituens exercet: quod erat &c.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XXV.

Quodlibet corpus in aqua demer&longs;um vndique &longs;tringitur con­primiturque ab ambiente aqua.

IN eadem figura quodlibet corpus durum, molle, vel fluidum FH in aqua demer&longs;um fixè detineatur. Dico ip&longs;um vndiquè &longs;tringi, ac comprimi ab ambien­te fluido FILHB. Quia &longs;olidum FH intra aquam re­tentum vnà cum ambiente aqua con&longs;tituit &longs;iphonem AKD in quo eius partes AK, & KD quie&longs;cunt, & æ­quilibrantur, ergò oportet vt aqua &longs;uprema AE con­primat, impellatque deorsùm &longs;olidi &longs;uper&longs;&longs;iciem FE, pariterque debet aqua &longs;ubiecta GK impellere &longs;ur­&longs;um &longs;olidi &longs;uperficiem GH non virtute propria, &longs;ed vi ponderis aquæ collateralis IM, &longs;imiliter &longs;olidi fa-ciem EH &longs;tringet lateraliter eadem aqua IM. Igitur vndique &longs;olidum FH &longs;tringitur comprimiturquè tan­quam à prælo: quod erat &c.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Et hìc notandum e&longs;t, quòd &longs;i corpus FH fuerit ve&longs;ica flexilis repleta corpore fluido concipi pote&longs;t con&longs;tans ex partibus non conden&longs;abilibus, vt e&longs;t a­qua, hydrargyrum, & aggregatum ex minimis &longs;ph&ecedil;­rulis cry&longs;tallinis; aut componatur ex partibus adeò raris, atque poro&longs;is, vt ingentem conden&longs;atione&mtail; pati po&longs;&longs;int, cuius natura Aer e&longs;t. In primo ca&longs;u li­cèt ve&longs;ica FH vndique æqualibus viribus compri­matur &longs;tringaturque, nihilominùs ob duritiem par­tium in ve&longs;ica contentarum, non poterit ip&longs;a ve&longs;ic&atail; con&longs;tringi, conden&longs;arique, &longs;cilicèt minus &longs;patium ex­plere, quàm prius occupauerat, eò quòd particulæ ip&longs;æ duri&longs;&longs;imæ fluidæ, vel den&longs;æ adinuicem fulciun­tur, veluti columnæ, aut fornices, quæ nullo pacto po&longs;&longs;unt frangi, vel con&longs;tringi, cùm è contrà partes aeris ob maximam earum raritatem facilè po&longs;&longs;int con­&longs;tipari, proindeque ve&longs;ica aera FH ad minus &longs;patiû redigi po&longs;&longs;it con&longs;trictis nempè eius poro&longs;itatibus.

His declaratis pro re&longs;olutione principalis proble­matis inquirendum e&longs;t, quo modo, & qua ratione à com­pre&longs;&longs;ione ponderis incumbentis pa&longs;&longs;io dolorifica in animali &longs;ub&longs;equatur.

Inquiritur cau&longs;a quare à pondere in­cumbente producitur compre&longs;&longs;io, &longs;ci&longs;&longs;io, diui­&longs;io continui, & proinde dolor.

Et primò experientia con&longs;tat, à pondere corporis manum v. g. prementis aliquando effici &longs;ci&longs;&longs;ionem, vt ab acie &longs;ecuris incumbentis, aliquando fractionem; multotiès luxari, & di&longs;rumpi articulos tractis nem-pèviolentèr tendinibus articulos colligantibus, & tandem fieri pote&longs;t contu&longs;io, & diffractio partiu&mtail; &longs;olidarum. Et hi&longs;ce omnibus modis continuitatis diui&longs;io in animali efficitur, à quà demum diui&longs;ion&etail; pa&longs;&longs;ionem dolorificam exoriri vulgò credunt.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Modò o&longs;tendendum e&longs;t, quòd diui&longs;io continui, & dolor procreari pote&longs;t ab aliquo &longs;ingulari pondere, quòd &longs;i pondus po&longs;tea comprimens augeatur, mul­tipliceturque, non proindè &longs;emper, & vniuersè ma­ior, &longs;ed minor, immò nulla &longs;ci&longs;&longs;ura, vel contu&longs;io, aut fractio in animali &longs;ub &longs;equi pote&longs;t; quod quidem licèt vid eatur paradoxum, poterit tamen facili ne­gotio demon&longs;trari.

PROP. XXVI.

Lamina dura, & &longs;texibilis, quæ à pondere incumbente flectitur, poterit à potentia duplicata dirigi.

SIt lamina chalybea AB parieti RS infixa, eique in­cumbat pondus C à quo lamina ip&longs;a deorsù&mtail; impul&longs;a curuitatem acquirat,

inflectaturque: adueniat po­&longs;tea vis motiua H æqualis pon­deri C, quæ contrario ni&longs;u &longs;ur­sùm impellat eamdem laminam: manife&longs;tum e&longs;t, quòd à duplici vi C, & H, non augetur curui­tas ip&longs;ius laminæ, &longs;ed ea potiùs dirigitur, quia ni­mirùm duæ vires contrari&ecedil; æqualibus momentis ope-rantes &longs;ibi mutuò impellunt, & proindè vna alterius vim, & actionem de&longs;truit, quantum ergo lamina in­flectitur deorsùm à pondere C, tantumdèm &longs;ursùm re­flectitur à contrario impul&longs;u ip&longs;ius H. Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XXVII.

Idip&longs;um adhibitis contrarijs ponderibus ope libræ verificatur.

APplicetur libra DE radio­

rum æqualium &longs;uffult&atail; in F, itaut terminus D infrà ex­tremitatem laminæ AB collo­cetur, & tunc po&longs;ito pondere G æquale ip&longs;i C in altero extremo libræ E, impel­letur &longs;ursùm terminus libræ, vel vectis D à vi pon­deris G, & ab illo lamina AB in directum retine­bitur contra vim compre&longs;&longs;iuam ponderis C, quando­quidem duo pondera C, & G inter &longs;e æqualia &longs;e mu­tuò impellunt, proindeque lamina intercepta AB, neque deorsùm, neque &longs;ursùm flectetur.

PROP. XXVIII.

Idip&longs;um alia ratione v&longs;urpata libra demon&longs;tratur.

SI nimirùm termino E im­

ponatur pondus IG du­plumip&longs;ius C, atque in D ap­plicetur pondus M æqual&etail; eidem C, manife&longs;tum e&longs;t, quòd pondus IG æquale e&longs;t duo-bus ponderibus C & M, & ideò æquilibrium efficie­tur, &longs;cilicèt intercepta lamina AB nil prorsùs flecte­tur, quia licèt à pondere &longs;upremo C deorsùm lami­na pellatur, repellitur infernè à corpore M non qui­dem propria vi, (cùm tendat deorsùm ob eius gra­uitatem) &longs;ed ab exce&longs;&longs;u ponderis IG &longs;upra M.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XXIX.

Animalis infra aquam demer&longs;i membra non flectentur, eò quòd vndique contrarijs viribus à fluido com­primuntur.

IN &longs;uperiori diagrammate habemus exemplum &longs;i­mile omninò corpori animalis in aqua natantis, nam licèt animalis brachium, ver. gra. AB, compri­matur à &longs;uperpo&longs;ita aqua C, non tamen flectetur de­orsùm, aut di&longs;rumpetur, cùm præ&longs;tò &longs;it aqua &longs;ubie­cta M, quæ &longs;ursùm manum brachiumque repellat, impediatque eius depre&longs;&longs;ionem, flexionemque, non quidem propria vi grauitatis eius, &longs;ed virtute compre&longs;­&longs;iua collateralis aquæ IG,

quæ in libra, vel &longs;iphone i­maginario, eo pondere, quo excedit grauitatem aquæ M, eam &longs;ursùm impellit, & pro­pterea Brachium AB &longs;u&longs;tinet ne à pondere &longs;upremo incuruetur, aut di&longs;rumpatur.

Ethoc (dicet aliquis) &longs;ufficeret ad luxatione&mtail; membrorum animalis euitandam, &longs;ed non proindè dolor compre&longs;&longs;iuus animalis vitari po&longs;&longs;et, quando­quidem partes carno&longs;æ, & tendino&longs;æ contunderen­tur diffringerenturque, atque vniuersè &longs;ci&longs;&longs;ura&mtail; aliquam paterentur.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens ponde­rat.

Vt verò fallacia huius ratiocinij detegatur.

Sed licèt lu­xati non con&longs;equatur, &longs;altem con­tu&longs;io, & dif­fractio par­tium anima­lis con&longs;equi debere vi­detur.

PROP. XXX.

Scis&longs;io con&longs;equens actionem Cunei, vel &longs;ecuris declaratur.

EFfectus con&longs;equens ad actionem cunei, & aciei &longs;ecuris, &longs;ci&longs;&longs;io nuncupari &longs;olet, quæ efficitur propterea, quòd dum cuneus intra corpus &longs;ci&longs;&longs;il&etail; in&longs;inuatur, huius partes hinc in de lateralitèr mouen­tur, & ab inuicem &longs;eparantur: hinc fit, quòd &longs;i par­tes&longs;ubiecti corporis minimè lateralitèr moueri po&longs;­&longs;ent, neque cuneus penetraret, nec &longs;ci&longs;&longs;io fieret: triplici verò modo motus laterales &longs;ubiecti corporis impediri po&longs;&longs;unt, primò, &longs;i gluten, quo partes &longs;ubie­cti corporis colligantur, fuerit immen&longs;æ virtutis, & arcti&longs;&longs;imæ vnionis, & duritiei; &longs;ecundò, &longs;i prædictæ partes inter &longs;e diui&longs;æ, vtarena, continerentur intra vas duri&longs;&longs;imum, cuius parietes cuilibet impul&longs;ui re&longs;i&longs;te­rent, nec præterea partes contenti corporis &longs;uble­uari&longs;ursùm po&longs;&longs;ent, tunc profectò nec penetratio cunei, nec &longs;ci&longs;&longs;io efficeretur; tertiò, &longs;i va&longs;e remoto adhiberentur vires impul&longs;iuæ lateralitèr contrariæ officium va&longs;is &longs;upplentes, tunc &longs;imilitèr &longs;ci&longs;&longs;io im­pediretur.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XXXI.

Diui&longs;io quæ effici pote&longs;t à compres&longs;ione in&longs;trumenti non acu­ti, veluti e&longs;t malleus, paritèr ad cunei actionem reducitur.

QVandoquidem particul&ecedil; corporis à malleo con­pre&longs;&longs;æ in&longs;inuantur directè, promouenturque intra alias collaterales particulas, & quia in­&longs;inuatio prædictarum partium effici non pote&longs;t ni&longs;i collaterales particulæ non contu&longs;æ locali motu late­rali tran&longs;portentur, hinc fit, quòd particulæ illæ con­pre&longs;&longs;æ immediatè actionem cunei referant: malleus verò &longs;it in&longs;trumentalis cau&longs;a mediata, &longs;eù potiùs vir­tus impellens particulas compre&longs;&longs;as, cuneos refe­rentes.

PROP. XXXII.

Ve&longs;ica arena, vel aqua repleta vndique, & in omni­bus partibus eius ab innumeris cuneis compre&longs;&longs;aneque &longs;cindi, neque flecti, neque figuram commu­tare pote&longs;t.

SVpponatur modò ve&longs;ica ABCD, quæ repleatur aqua, vel hydrargyro, aut arena, vel globulis cry&longs;tallinis minuti&longs;&longs;imis, tunc &longs;i huiu&longs;modi ve&longs;ica à pauimento RS fulciatur, atque ei &longs;uperponatur acies &longs;ecuris, vel nouaculæ I, procùl dubio, aut ve&longs;ic&atail; &longs;cindetur, aut &longs;altèm fluidum, &longs;iue arena content&atail; cedet, & ver&longs;us latera ve&longs;i­

cæ tran&longs;portabitur; at &longs;i in­telligantur innumeræ acies &longs;ecurium, vndique compri­mentes ve&longs;icam, itaut null&atail; eius pars intacta relinquatur: primò manife&longs;tum e&longs;t, &longs;ci&longs;&longs;io­nem prohiberi, quandoquidem longa, & continua­ta &longs;eries acierum &longs;e&longs;e con&longs;equentium, & &longs;e mutuò lateralitèr tangentium ab&longs;que vlla interruptione æ­quiualent corpori obtu&longs;o, proindeque acuties ill&atail; omninò de&longs;truitur, & Proptereà non &longs;equetur &longs;ci&longs;&longs;io quæ ab&longs;que acie acuta fieri nequit. Secundò non fi­et contritio, atque depre&longs;&longs;io alicuius partis prædi­ctæve&longs;icæ, quandoquidem non pote &longs;t &longs;uprema pars eius A deprimi versùs C, quin aqua, vel arena ex­pul&longs;a recipiatur ad latera B, & D, &longs;ed hic quoqu&etail; æqualibus viribus comprimitur lateralitèr ve&longs;ic&atail;, igitur non pote&longs;t ibidem perduci fluidum, vel are­na compre&longs;&longs;a; & propterea ve&longs;icæ circumcircà viribus æqualibus compre&longs;sæ nulla particula cedet; & quia aliundè materia ip&longs;a fluida, vel arena talis con&longs;i&longs;ten­tiæ e&longs;t, vt &longs;tringi, conden&longs;ari, & ad minus &longs;patiu&mtail; redigi nequeat, fit vt ve&longs;ica illa, & aqua vel arena in ea contenta, neque &longs;cindatur, neque flectatur, neque vllo pacto figuram commutet quotie&longs;cumque vndique circùmcirca ab æqualibus viribus compri­matur.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XXXIII.

Idip&longs;um verificatur quotie&longs;cumque prædicta ve&longs;ica in ip&longs;a aqua demergitur.

IBi enim nedùm à perpendiculariter incumbent&etail; aqua comprimitur, &longs;ed etiam ab infima, & colla­terali, vndequaque, & vniuersè æqualibus viribus impellitur, con&longs;tringitur que, vnde fit vt licèt ve&longs;i­ca &longs;it tenui&longs;&longs;ima, non po&longs;&longs;it tamen vnquam diffringi à pondere licèt immen&longs;o &longs;uper&longs;tantis aquæ, vel hy­drargyri, nec contu&longs;ionem, aut diffractionem vllam pati; & ratio e&longs;t quia licèt tota ma&longs;&longs;a contenta intra ve&longs;icam &longs;it fluida, mollis, & cedens, nihilominus quia minimæ particulæ fluidi, vel arenæ &longs;e mutuò fulciunt, & natiua duritie compre&longs;&longs;ioni re&longs;i&longs;tunt, fit vt conden&longs;ari, aut con&longs;tringi nequeant, & ab vni­uer&longs;ali circumambiente compre&longs;&longs;ione ne minimum alteretur eius figura, neque &longs;itus partium.

PROP. XXXIV.

T andem o&longs;tenditur quare animal nullam noxam excom­pres&longs;ione aquæ incumbentis pati debeat.

NOn &longs;ecùs in corpore animalis continentur in­tra eius pellem partes aliæ quidem duræ, & &longs;olidæ, vt &longs;unt o&longs;&longs;a, aliæ molles, vt &longs;unt tendines, nerui, membranæ, & mu&longs;culi; aliæ verò &longs;unt fluidæ, aqueæ, vel oleagino&longs;æ continentes innumeras alias particulas &longs;alis, & aliorum corporum. Modò o&longs;&longs;a in animali di&longs;rumpi, aut iuxari non po&longs;&longs;unt, vt o&longs;ten­&longs;um e&longs;t Prop. 29. ni&longs;i pondus incumbens ex vn&atail; parte tantum comprimat, vt conting it in baiulis; at &longs;i compre&longs;&longs;io &longs;ubdiuidatur, vt &longs;phæricè, &longs;ursùm, & deorsùm, & lateraliter æqualibus viribus comprimat, ita vt nulla cutis particula libera à pre&longs;&longs;ione &longs;it, tunc quidem e&longs;t impo&longs;&longs;ibile vt &longs;ci&longs;&longs;io, vel luxatio &longs;ub&longs;e­quatur; idip&longs;um dicendum e&longs;t de neruis, ac mu­&longs;culis, qui licèt &longs;int molles, tamen quia con&longs;tant ex fibris con&longs;i&longs;tentibus, & tenaci&longs;&longs;imis, fit vt vniuersè po&longs;&longs;int &longs;e vici&longs;&longs;im fulcire, & re&longs;i&longs;tere vniuer&longs;ali, & &longs;phæri­cæ compre&longs;&longs;ioni: idem dicendum e&longs;t de &longs;anguine, & alijs humoribus animalis, qui aquæ naturam par­ticipant, & &longs;icuti aqua manife&longs;tam conden&longs;ationem non patitur, &longs;ic quoque animalis humores in cauita­tibus va&longs;orum eius contenti contritionem pati qui­dem po&longs;&longs;unt ab impul&longs;u facto ab vnico, vel paucis locis peculiaribus; at ab vniuer&longs;ali, & circumqua­que facta compre&longs;&longs;ione minimè po&longs;&longs;unt è &longs;uis va&longs;is expelli, ac diuelli. quotie&longs;cumque igitur partes &longs;o­lidæ, tendino&longs;æ, aut carno&longs;æ, aut humorales, &longs;ci&longs;&longs;i­onem, luxationem, contu&longs;ionem, aut aliam quam­libet &longs;itus mutationem non patiuntur e&longs;t impo&longs;&longs;ibi­le, vtdolor, aut pa&longs;&longs;io in animali &longs;ub&longs;equatur, quæ à nulla alia cau&longs;a, quàm à continui diui&longs;ione creari pote&longs;t. Quà propter cùm vrinatores in profundo ma­ris demer&longs;i ab aqua æquali vi vndique compriman­tur, &longs;upernè &longs;cilicèt, infernè, & lateralitèr circum-circa à pondere ip&longs;ius aquæ, &longs;equitur ex demon&longs;tra­tis Prop. 29. & 32. nullam &longs;ci&longs;&longs;ionem, luxationem, aut contu&longs;ionem in eis creari, &longs;cilicèt nullam conti­nui diui&longs;ionem à pondere aquæ incumbentis produ­ci, igitur nullam noxam, nec &longs;en&longs;um dolorificu&mtail; patientur.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Sed dices, e&longs;to nullam luxationem, fractionem, aut contu&longs;ionem vrinatores &longs;ub aqua pati debere, &longs;altem &longs;en&longs;u tactus perciperent compre&longs;&longs;ionem ponderis illius va&longs;tæ molis aquæ incumbentis, quam non ne­gamus exercere &longs;uam grauitatem &longs;upra corpus ani­malis demer&longs;i. Hoc profectò e&longs;t, quod negamus, nam ratio, quare &longs;en&longs;u pa&longs;&longs;ionem ab incumbente ponde­re illatam percipimus extra aquam po&longs;iti e&longs;t, qui&atail; no&longs;træ partes ob articulorum flexilem disiunctionem deorsùm pelluntur à premente graui, & idcò cogi­mur ingenti vi fibras mu&longs;culorum tendere, & con­trahere, vt lap&longs;um membrorum impediamus; at in­fra aquam ni&longs;u illo laborio&longs;o mu&longs;culorum non in­digemus, proptereà quòd aqua &longs;ubiecta vices mu­&longs;culorum &longs;upplet repellendo æquali vi &longs;ursùm aquam &longs;upremam vnà cum natante animali; & proinde &longs;u­prema aqua, &longs;nffulta à &longs;ubiecta virtute ponderis a­quæ collateralis cum qua æquilibratur, nullo pacto animalis partes flectere, & deprimere pote&longs;t, & ideò mu&longs;culi otio&longs;i &longs;unt, & propterea nullam aliam pa&longs;­&longs;ionem animal &longs;entiet pr&ecedil;ter vniuer&longs;alem con&longs;trictio­nem &longs;ui corporis; at quia, vt dictum e&longs;t, partes dur&ecedil;, molles, & fluidæ animalis compre&longs;&longs;ioni non cedunt ob earum con&longs;i&longs;tentiam, hinc fit, vt nullam pa&longs;&longs;ionem dolorificam &longs;entiant.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

PROP. XXXV.

Vrinatores constrictionem aliquam infra aquam patiuntur ob acrem in eis contentum.

NOn tamen negari pote&longs;t ade&longs;&longs;e in animali par­tes aliquas aereas, & &longs;pirito&longs;as, quas conden­&longs;ari, ac con&longs;tringi po&longs;&longs;e manife&longs;tum e&longs;t, vnde à cir­cumambiente con&longs;tipatione, quam patiuntur vrina­tores in profundo maris con&longs;tituti, nece&longs;&longs;ariò aer in pectoris cauitate contentus ob re&longs;pirationis ne­ce&longs;&longs;itatem, & particulæ illæ minimæ aereæ per cor­pus eius di&longs;per&longs;æ conden&longs;ationem aliquam patiun­tur; proindequè motiones internæ &longs;pirituum for&longs;an impediuntur, & naturalis con&longs;titutio partium ani­malis perturbatur; & inde in&longs;en&longs;ibilis tran&longs;piratio impedita laxitudinem, & pa&longs;&longs;ionem dolorifica&mtail;, &longs;en&longs;umque &longs;uffocationis creat; & hoc quidem expe­rimur quotie&longs;cumque à ve&longs;te nimis angu&longs;ta con&longs;trin­gimur. Sed notandum e&longs;t, compre&longs;&longs;ionem ve&longs;tis non e&longs;&longs;e vniuer&longs;alem, & tunc quidem pote&longs;t &longs;anguis ex­pelli versùs faciem, & partes nudatas, & à ve&longs;ti­bus non con&longs;trictas, quod non contingeret &longs;i vni­uersènè minima cutis particula libera à compre&longs;&longs;io­ne e&longs;&longs;et. Sic cùm manus immergitur intra hydrar­gyrum, patimur quidem &longs;en&longs;ibilem compre&longs;&longs;ionem dolorificam nedùm quia partes aereæ, & &longs;pirito&longs;æ con&longs;tringuntur, & conden&longs;antur, &longs;ed præcipuè quia compre&longs;&longs;io efficitur in peculiari loco, & non vni­uersè.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Ex qua fit vt &longs;anguis à venis manus extrudatur ver­sùs brachium non demer&longs;um intra mercurium, & in­de duæ pa&longs;&longs;iones &longs;ub&longs;equantur, vna quidèm con&longs;tri­ctionis, altera verò e&longs;t ea, quæ ab impedita, & in­terrupta &longs;anguinis circulatione per totam manu&mtail; oritur.

Sed obijciet forsàn qui&longs;piam exprædicta con&longs;tri­ctione partium aerearum in animali contentarum ali­quam dolorificam pa&longs;&longs;ionem oriri, quam vrinatores in profundo maris con&longs;tituti percipere deberent. Hoc tamen vltrò conceditur, reuerà enim in profun­do maris pa&longs;&longs;io aliqua con&longs;trictiua in vniuer&longs;o cor­pore percipitur, pariterque aer in pectore animalis contentus con&longs;tringitur, & conden&longs;atur, &longs;ed no&ntail; proindè ingens pa&longs;&longs;io &longs;uffocatiua ob cra&longs;&longs;itiem con­den&longs;ati aeris in pectore contenti &longs;ub&longs;equetur, quan­doquidem experimur nullam noxam, aut &longs;en&longs;um &longs;uf­focatiuum percipi, quotie&longs;cumque aer in&longs;piratus valdè attenuatur, rare&longs;cit, aut conden&longs;atur; &longs;ic enim in hypocau&longs;to, atque in montis alti&longs;&longs;imi &longs;ummitate aer valdè rarus attenuatu&longs;que e&longs;t, re&longs;pectu eius, qui in profunda aliqua valle, vel in loco ceno&longs;o reperi­tur, qui valdè cra&longs;&longs;us, & conden&longs;atus e&longs;t, nihilomi­nùs, neque in ip&longs;a re&longs;piratione læ&longs;io, aut pa&longs;&longs;io ali­qua manife&longs;ta percipitur, neque in habitu totius cor­poris aer diuer&longs;imodè rarefactus differentiam nota-tu dignam, & à nobis perceptibilem parit: igitur vrinatores in profundo maris demerfi nullam pa&longs;&longs;io­nem dolorificam percipere po&longs;&longs;unt licèt &longs;upponatur quòd ab aqua incumbente pondero&longs;a compriman­tur, & conden&longs;etur aliquo pacto aer in thorace eo­rum contentus. Quaproptèr ex hi&longs;ce omnibus con­cludere licèt aquam grauitatem exercere quandò quie­&longs;cit in &longs;uo naturali loco, nempè quando in ip&longs;amet vniuer&longs;ali aqua fulcitur, & &longs;u&longs;tentatur.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Non de&longs;unt po&longs;tea qui Renato Cartefio nimis addicti velint partes minimas cuiuslibet fluidi, & præcipuè aquæ nunquàm quie&longs;cere, &longs;ed &longs;emper agi­tari, accircumuolui per ipsammet aquam. Hinc &longs;u­bindè inferunt partes aquæ in ip&longs;amet aqua con&longs;ti­tutas, nec grauitatem, nec leuitatem habere, cùm po&longs;&longs;int qua qu an ersùm &longs;ursùm, atque deorsùm mo­ueri; nos è contrà.

Carte&longs;iani cen&longs;ent par­tes aquæ in ip&longs;a aqua, nec grauita­re, nec leui­tare, quia &longs;ursùm, & deorsùm con­tinentèr mo­uentur.

PROP. XXXVI.

Ostendemus, quòd licèt aqua in ip&longs;a aqua quomodolibèt con­uoluatur, agiteturque, nihilominùs perpetuò retinet propriam grauitatem, e amque perpetuò exercet.

INtelligatur vas aqua plenum ABCD &longs;u&longs;pen&longs;u&mtail; in extremo termino H libræ radiorum æqualium HL, cuius centrum I, & pendeat pondus R ab alte­ro extremo libræ L, itaut libra quie&longs;cat, & æqueli­bretur vas aqueum AC cum corpore R, & hoc qui-

dem verificetur, dum aqua in prædicto va&longs;e contenta prorsùs quie&longs;cit, &longs;altè&mtail; quoad &longs;en&longs;us apparentiam, &longs;i po&longs;tea aqua agitetur, vt nimitùm pars EF de&longs;cen­dat ver&longs;us va&longs;is fundum, reliqua verò pars FG, &longs;ur­sùm a&longs;cend at motu quodam vertigino&longs;o, fi veru&mtail; e&longs;t, quòd motus a&longs;cen&longs;iuus ip&longs;ius aquæ indicat de­fectum grauitatis eius, tunc per&longs;euerante dicto mo­tu a&longs;cen&longs;us minui deberet pondns totius va&longs;is AC, & propterea libra HL non quie&longs;ceret, &longs;ed deprime­retur pondns R, quod tamen repugnat &longs;en&longs;us eui­dentiæ; non igitur ex eo quòd aqua mouetur in ali­quo va&longs;e carebit propria, & natiua grauitate, &longs;icuti homo a&longs;cend'ens per &longs;calam extremo termino libræ alligatam æquali momento libram premeret, ac &longs;i idem homo in &longs;cala quie&longs;ceret, quia nimirùm dum a&longs;cendit non minus &longs;u&longs;tentatur quàm dum quie&longs;cit.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Sed dices, cum motus vertigino&longs;us aquæ fieri non po&longs;&longs;it ab&longs;que eo quod vna pars de&longs;cendat, & reli­qua &longs;ubleuetur, e&longs;t valdè probabile, vt &longs;icut a&longs;cen&longs;us aquæ FG indicat defectum grauitatis, cùm prædi­ctus motus &longs;upponat impetum à quo &longs;ursùm propel­latur &longs;icuti &longs;axum quod &longs;ursùm proijcitur in actu &longs;ui a&longs;cen&longs;us, neque graue dici pote&longs;t, nec grauitatem exercet, proptereà quòd ab impetu impre&longs;&longs;o con­trario grauitati, vel ip&longs;amet grauitas de&longs;truitur, vel impeditur, & ce&longs;&longs;at eius operatio. Oppo&longs;itum con-tinget in aqua de&longs;cendente EF quæ videtur habere nedùm vim propriæ grauitatis, &longs;ed in&longs;uper impetum quo deorsùm fertur, &longs;icuti &longs;axum, quod deorsù&mtail; proijcitur, vim, & percu&longs;&longs;ionem infert nedum men­&longs;uratam à gradu eius ponderis, &longs;ed etiam ab impe­tu eius de&longs;cen&longs;iuo; qua propter vis, quæ &longs;ubtrahitur ab aqua a&longs;cendente FG, &longs;uperadditur grauitati aquæ de&longs;cendenti EF, & &longs;ic duplicatur vis eiu&longs;dem aquæ de&longs;cendentis qua fundum va&longs;is BC comprimitur; cum igitur id, quod &longs;ubtrahitur ab aqua a&longs;cendente FG &longs;uperaddatur ponderi aquæ de&longs;cendentis EF com­pen&longs;abitur defectus cum additamento impetus con­pre&longs;&longs;iui, proindeque non imminuetur pondus totius aquæ in va&longs;e AC contentæ, & hæc erit cau&longs;a, quare etiam po&longs;t aquæ agitationem pondus eius in libr&atail; non alteratur, nec imminuitur.

Cap. 3. flui­dum in &longs;uo toto quit­&longs;cens ponde­rat.

PROP. XXXVII.

Reijcitur difficultas contra præcedentem propo&longs;itionem adducta.

SEd facili negotio inefficacia huius ratioc inij o&longs;ten­di pote&longs;t, primò experientia, &longs;ecundò ratione. Quoad primum, &longs;u&longs;pendatur vas aqueum AC duobus filis AH, DL alligatis in extremitatibus eiu&longs;dem li­bræ HL radiorum æqualium, &longs;u&longs;pendaturque libra cum va&longs;e ab illius centro I, manife&longs;tum e&longs;t, quando aqua quie&longs;cit, nec agitatur, &longs;i eri æquilibrium, qui&atail; &longs;cilicèt centrum grauitatis M totius va&longs;is, & aquæ in-

cidit præcisè in recta linea MI perpendiculari ad horizontem, quæ per centrum &longs;u&longs;pen&longs;ionis ducitur. Modò agitetur aqua va­&longs;is, vt nimirùm pars EF de&longs;cen­dat, pars verò KG, &longs;ursùm ten­dat, & hoc per aliquod tempus per&longs;eueret continuatis reuolu­tionibus, dummodò planities libellæ, AD non alte­retur; frigitur verum e&longs;t in tali ca&longs;u, quòd grauitas a&longs;cendentis aquæ KG de&longs;truitur quatenus à virtute impul&longs;iua proiectitia &longs;ursùm impellitur, & è contrà &longs;i grauitas, & impetus aquæ de&longs;cendentis EF dupli­catur, quia eius ponderi &longs;uperadditur vis proiectiu&atail; deorsùm, igitur medietas va&longs;is MAB, aut leuis effi­cietur, aut valdè eius grauitas pri&longs;tina imminut&atail; erit, & è contrà reliqua va&longs;is medietas MDC duplò grauior facta erit, proindeque terminus libræ L deprimetur, eleuabiturque oppo&longs;itus ter­minus libræ H, quod tamen fal&longs;um e&longs;t, igitur quo­modocumque aqua agitetur, dum in ip&longs;amet aqua, & in proprio loco continetur, neque amittit ob a&longs;cen­&longs;um, nec acquirit ob de&longs;cen&longs;um nouam grauitate&mtail;.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Sed faciliùs hoc experieris, &longs;i intra vas ABCD in­&longs;eratur rota EGKF perpendicularitèr horizonti ere­cta, & parietibus oppo&longs;itis va&longs;is infixo axe eius i&ntail; M vt facilè rota conuerti po&longs;&longs;it. Et &longs;iquidem centrum grauitatis totius aggregati cadit in recta line&atail; IM perpendiculari ad horizontem, tunc &longs;iue rot&atail; quie&longs;cat, &longs;iue circa eius axim

M conuertatur libra &longs;emper in &longs;itu horizontali æquilibra­ta perfi&longs;tet.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Vt verò ratio huius effectus percipiatur, recurrendum e&longs;t ad centri grauitatis definitio­nem, ex qua habetur quòd corpus quodlibet &longs;u&longs;pen­&longs;um à centro grauitatis eius quomodocumque reuol­uatur circa centrum, &longs;emper æquilibrari, & haber&etail; partes æqualium momentorum, vnde infertur, quòd vniuer&longs;a vis, qua corpus aliquod tendit deorsùm, &longs;ci­licet grauitas eius, exercetur in vnico illo puncto, quod centrum grauitatis eius vocatur. Hinc deduci­tur, quod &longs;i rota, &longs;iuè pila &longs;u&longs;tineatur ex centro gra­uitatis eius &longs;iuè quie&longs;cat, &longs;iuè moueatur, numquam centrum grauitatis &longs;itum commutabit, aliàs daretur motus perpetuus, qui naturæ legibus repugnat.

Similitèr &longs;i concipiatur fi&longs;tula vitrea inflexa ad modum anuli, vt e&longs;t EFGK, &longs;itque prædicta fi&longs;tul&atail; plena aqua &longs;ituata perpendiculari­

tèr &longs;uper planum &longs;ubiectum RS à quo fulciatur; habebit profectò cen­trum grauitatis in eius puncto in­termedio N, dum quie&longs;cit aqua i&ntail; prædicto anulo, at &longs;i reuoluatur vt nimirùm pars EFG de&longs;cendat, reliqua verò GKE &longs;ursùm a&longs;cendat, non proindè centrum grauitatis tran&longs;­feretur ab N versùs O, &longs;cilicèt intra &longs;emicirculu&mtail; aquæ de&longs;cendentis, nam per&longs;euerante vertigine, &longs;ci­licèt translato centro grauitatis vltrà medium in O &longs;emper &longs;emianulus EFG grauior e&longs;&longs;et, quàm GKE, & propterea ille &longs;emper de&longs;cenderet, hìc verò &longs;em­per a&longs;cenderet, proindeque anulus excurreret mo­tu perpetuo progre&longs;&longs;iuo, quod e&longs;t fal&longs;um. per&longs;i&longs;tit ergo centrum grauitatis &longs;emper in centro N anuli, &longs;iue aqua in eo contenta quie&longs;cat, &longs;iuè circumduca­tur, nam ob contiguitatem partium aquæ non pote&longs;t moueri vna pars aquæ F v. g. quin vniuer&longs;a aqu&atail; EKG æquali velocitate reuoluatur, proindeque non vnica pars tantùm, &longs;ed aqua tota impulsum, & impe­tum acquirit, non &longs;ecùs ac rota lignea tota &longs;imul ic­tum recipit atque circa centrum grauitatis eius æqui­libratur, pari modo aqua contenta in va&longs;e AC ante præmi&longs;&longs;æ figuræ, licèt &longs;it fluida, habet tamen pun­ctum M circa quod partes habent æqualia momenta, perinde ergo &longs;e habent ac &longs;i vniuer&longs;a aqua in prædi­cto va&longs;e contenta dura e&longs;&longs;et, & con&longs;i&longs;tens vt rota li­gnea, vel intra fi&longs;tulam anularem EFKG content&atail; e&longs;&longs;et in qua reuoluta, &longs;iue quie&longs;cente rota, aut aqua &longs;emper centrum grauitatis eius in eodem &longs;itu per&longs;e­uerare debet, & proinde libra HL quie&longs;cet in eodem &longs;itu horizontali. Igitur dubitandum non e&longs;t aqua&mtail; in &longs;uo toto collocatam, grauitatem exercere, &longs;iuè illa omninò ibidem quie&longs;cat, &longs;iuè quomodolibet agite­tur, & circumuoluatur.

Cap. 3. flui­dum in &longs;uo toto quie­&longs;cens pon­derat.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Po&longs;itiuam leuitatem in rerum natura non dari.

CAP. IV.

HActenùs con&longs;iderauimus grauitatem non om­nium corporum fluidorum, &longs;ed tantummodò aquæ, hydrargyri, & &longs;imilium, de quorum pondero­&longs;itate nemo dubitat, manife&longs;tè enim deorsùm ten­dunt, atque de&longs;cendunt. difficultas vertitur circ&atail; reliqua corpora, quæ &longs;ursùm a&longs;cendere videntur, vt &longs;unt ligna, & alia corpora, quæ in aqua &longs;ursùm a&longs;cen­dunt, in his enim grauitatem ponere, videtur contra communem conceptum; nihilominùs cum melioris notæ Philo&longs;ophis o&longs;tendere conabimur omnia cor­pora fluida elementaria grauitatem habere, leuita­tem verò po&longs;itiuam ab&longs;olutè in natura non dari, ita­que o&longs;tendendum e&longs;t omnia corpora elementaria ha­bere vim &longs;e &longs;e vniendi ad efformandum no&longs;trum Sy­&longs;tema, &longs;cilicèt habere facultatem motiuam de&longs;cen­dendi versùs centrum globi terre&longs;tris, & huiu&longs;modi vis vocatur grauitas. Et primo loco examinabimus argumenta Ari&longs;totelis facta contra Platonem, & De­mocritum prædictæ &longs;ententiæ a&longs;&longs;ertores, po&longs;tea ad examen reuocabimus rationes eiu&longs;dem Ari&longs;totelis, quibus leuitatem po&longs;itiuam &longs;tatuere conatur. Tertio loco afferam demon&longs;trationes, quibus euincitur non dari leuitatem po&longs;itiuam; & tandem con&longs;idèrabo ea omnia, quæ pa&longs;sìm à melioribus Peripateticis con-tra Platonicam &longs;ententiam a fferuntur, quæ peruene­re ad meam notitiam.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Quòad primum Ari&longs;toteles in&longs;ectatur Democriti, Platoni&longs;que po&longs;itionem, &longs;ed more &longs;uo, non contr&atail; &longs;ententias, at contra mera verba eorum argumenta­tur, &longs;cilicèt quod terræ grauitas maior, quàm aeris pendeat à copia triangulorum, quæ maior in terra, quàm in aere exi&longs;tit, a&longs;&longs;umitque prædicta triangula, ac &longs;i e&longs;&longs;ent &longs;uperficies planæ omninò indiui&longs;ibiles, quod patet fal&longs;um e&longs;&longs;e, cùm in Platonica po&longs;ition&etail; atomi triangulares &longs;int corpora, non autem &longs;uperfi­cies indiui&longs;ibiles.

Phy&longs;ic.lib.4. cap.2.

Præterea contra Democritum, ait, grandem aeris ma&longs;&longs;am, veluti e&longs;&longs;et &longs;phæra aerea habens diametrum decem cubitorum, habere maiorem copiam, & abun­dantiam pleni, & materiei, quàm exigua pila aquea habens diametrum vnius digiti, & proindè pila ae­rea grauior e&longs;&longs;e deberet, & deor&longs;um de&longs;cendere, & è contrà aquea vt leuis &longs;ursùm eleuari deberet. Hoc, inquam, argumentum non afficit Democritum, qui numquam tantam ab&longs;urditatem &longs;omniauit, numquam enim con&longs;iderauit plenum &longs;olitarium, &longs;ed vnà cum pleno ingentem vacui molem augmentatam in ill&atail; grandi aerea pila, & &longs;emper maiori cum proportio­ne, quàm &longs;e habeat plenum aeris ad plenum aquæ. Quam exceptionem parùm &longs;incerè Ari&longs;toteles &longs;ub &longs;i­lentio inuoluit, quoniam exi&longs;tente aere rariore, quam &longs;it ip&longs;a aqua, habebit pars vacua ad partem plena&mtail; aeris maiorem proportionem, quàm habet pars va-cua ad partem plenam ip&longs;ius aquæ, & permutando, moles vacua aeris ad molem vacuam aquæ maiorem proportionem habebit, quàm moles plena aeris ad molem plenam aquæ, & proindè qu&ecedil;libet ampla ae­ris moles habebit maiorem cau&longs;am alleuiationis quam aqua, po&longs;ito quòd huiu&longs;modi cau&longs;a &longs;it vacuum, & è contra in eodemmet aere debilior erit cau&longs;a graui­tatis, quæ ab ip&longs;o pleno, & ab eius men&longs;ura de&longs;u­mitur, itaque in grandi illa &longs;phæra aerea &longs;imùl cum aug­mento partis plenæ decies maiori, quam in exigua pila aquea, &longs;uperadditur quoque cau&longs;a contraria, nemp è alleuiationis, quæ e&longs;t vacuum plu&longs;quam milliès ma­ior, quàm &longs;it illud quod in ip&longs;a aqua continetur; cùm igitur tàm enormiter excre&longs;cat, & &longs;uperet pro­portio vacuitatis reliquam proportionem plenitudi­nis in prædictis duobus elementis numquam poterit ampla pila aerea grauior effici ob augmentum eius plenitudinis, & partis materialis, quando ip&longs;a in &longs;e quoque continet contrariam cau&longs;am, quæ eam leuem reddit multò magis multiplicatam, & hæc e&longs;t inani­tas, & vacuum. Eiu&longs;dem farinæ e&longs;t longa illa &longs;eries argumentorum toties ab Ari&longs;totele contra antiquos adductorum.

Ari&longs;t. ibid.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Præterea verum non e&longs;t, a&longs;&longs;igna&longs;&longs;e antiquos &longs;pa­tio vacuo motum, aut virtutem operandi, &longs;ed tantun­modò principio materiali, ac pleno eam concede­bant, quod per&longs;picuè ex eodem Ari&longs;totele percipitur, refert enim antiquos po&longs;ui&longs;&longs;e omnia corpora elemen­taria grauia, & pondero&longs;a, &longs;ed magis, aut minùs, prout plenum, & principium materiale deficeret, aut abundaret in ip&longs;is; & in&longs;uper ait, quòd a&longs;cen&longs;us &longs;ursùm aliquorum corporum, nempè ignis, non à prin­cipio aliquo po&longs;itiuo, &longs;cilicèt leuitate pendere an­tiquì cen&longs;ebant, &longs;ed effici huiu&longs;modi a&longs;cen&longs;um per extru&longs;ionem factam à fluidis corporibus ambienti­bus pondero&longs;ioribus. Si igitur hæc fuit anti quoru&mtail; &longs;ententia, quomodo eis tribui pote&longs;t tàm enormis ab&longs;urditas, quòd nimirum vacuum moueatur, impel­lat, habeat &longs;itum, & regionem &longs;ursùm, versùs quam tendit? quomodò, inquam, hæc affirmare poterant il­li, qui apertè aìe bant motus omnes naturales corpo­rum elementarium tendere deorsùm omne&longs;que pen­dere ab vnico principio po&longs;itiuo, &longs;cilicèt à pleno, & materia corporea? nec quia aer &longs;ursùm impellitur, extruditurque, inde &longs;equitur, quòd vacua in aere con­tenta moueantur, atque &longs;ursùm a&longs;cendant, nam &longs;i va­cuum nil aliud e&longs;t, quàm &longs;patium, id erit immobile, & proindè aer &longs;ecum non a&longs;portabit vacuum ip&longs;um &longs;ursùm, &longs;ed in ip&longs;o a&longs;cen&longs;u &longs;ucce&longs;&longs;iuè acquiret noua &longs;patia: relinquendo præcedentia, quæ &longs;unt omninò immobilia. at &longs;i nomen vacui meram pleni priuatio­nem, ac nihilum &longs;ignificet, certum e&longs;t quòd nihilum moueri non pote&longs;t, nec impellere, nec ab vno ad alium locum migrare.

Ibidem.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Po&longs;tquam con&longs;iderauimus Ari&longs;totelis argumenta contra Antiquos, qui leuitatem po&longs;itiuam omninò negabant, re&longs;tat modò vt eiu&longs;dem Ari&longs;totelis ratio­nes pro leuitatis &longs;tabilimento, & po&longs;itione con&longs;ide-remus. Præcipua eius ratio hæc e&longs;t, quia reperiun­tur duo loca contraria in natura &longs;ursùm, & deorsùm, &longs;cilicèt circumferentia, & centrum mundi, &longs;eu ter­ræ; & euidentèr apparet, quòd terra infima e&longs;t, & &longs;ubiacet omnibus alijs corporibus mundanis, demer­gitur enìm de&longs;cendendo infrà aerem, & infra aquam, quou&longs;que adlocum infimum perducatur, nempè ad centrum, quando nimirum ea non impeditur; hinc deducit, ergo terra e&longs;t ab&longs;olutè, & &longs;implicitèr gra­uis, & non relatiuè. E contrà videmus aerem pene­trare den&longs;itatem ip&longs;ius aquæ, & a&longs;cendere &longs;uper eam, & ignem perforare den&longs;itatem tum aqu&ecedil;, tùm aeris, per­ducique ad &longs;upremam, & extremam &longs;uperficiem ae­ris, veluti ad locum &longs;uum naturalem &longs;upremum, vbi tandèm quie&longs;cit, nec vlteriùs mouetur. Et quia, in­quit, ignis omnibus &longs;upereminet, igitur e&longs;t &longs;impli­citèr, & ab&longs;olutè leuis; terra omnibus &longs;ubijcitur, igi­tur e&longs;t ab&longs;olutè grauis.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Vt verò vim, & energiam Ari&longs;totelici ratiocinij percipiamus, & exactè perpendamus, oportet vt &longs;ta­tum controuer&longs;iæ memoremus, &longs;cilicèt the&longs;im Pla­tonis, atque Democriti, quam Ari&longs;toteles redargue­re profitetur, ante oculos ponamus, & po&longs;tea argu­mentum ab Ari&longs;totele adhibitum con&longs;ideremus. Et primò ratum per&longs;pectumque e&longs;t duplici modo fieri po&longs;&longs;e vtignis &longs;ursùm perducatur, & &longs;uper omnia e­lementa emineat, aut nempè quia ignis &longs;ponte &longs;u&atail; mouetur &longs;ursùm à principio intrin&longs;eco, & naturali, &longs;cilicèt à leuitate, vel potiùs, quia ibidem ignis ex-pellatur, extrudaturque à maiori grauitate aliorum corporum fluidorum, veluti e&longs;t aer, & aqua; & hæc po&longs;trema erat Platonis, & Democriti &longs;ententia, quam Ari&longs;toteles redarguere tenebatur: Argumentum ve­rò Ari&longs;totelis aliam longè diuer&longs;am propo&longs;itionem à nemine in dubium reuocatam petit, atque in&longs;ecta­tur; nil enim aliud obijcit, quàm phenomenon, quod &longs;en&longs;ibus patet, & quod aduer&longs;arij vltrò concedebant, &longs;cilicet quòd omnes videmus ignem &longs;upra aerem ele­uari; at tenebatur potius Ari&longs;toteles demon&longs;trar&etail; ignem a&longs;cendere non quia à medio fluido grauiori extruditur impelliturque fursùm, &longs;ed quia &longs;ponte à vi propria leuitatis mouetur, quod non præ&longs;titit, pote­rit ergò vocari Ari&longs;totelicum ratiocinium potiùs pe­titio, quàm demon&longs;tratio.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Non de&longs;unt Peripatetici, qui vt vigorem, & vi&mtail; addant Ari&longs;totelico ratiocinio, aiunt ab&longs;urdum e&longs;&longs;e omninò corpora naturalia moueri ad propria loc&atail; non à principio intrin&longs;eco, & eis à natura in&longs;ito, &longs;ed à violentia externi corporis per extru&longs;ionem, vnde deducitur, quòd natura in operationibus tàm nece&longs;­&longs;arijs, & vtilibus fuerit deficiens, cùm nimirum in­digeat &longs;timulis, & impul&longs;u violento, & coactione, quæ cùm re&longs;i&longs;tentiam, & violentiam includat, vide­tur operatio non naturalis, & propterea neque per­petua, neque vtilis ad ordinem, & con&longs;eruationem vniuer&longs;i.

Huic &longs;pecio&longs;o ratiocinio re&longs;ponderi pote&longs;t, e&longs;&longs;&etail; regulam fallacem, quòd vbicumque actiones, & o-perationes non fiunt &longs;ponte, &longs;ed violentèr, tunc pro­tunciari debeat prædictas operationes à natura, at­que à principio naturali factas non e&longs;&longs;e.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Vno verbo, erit quoque naturalis operatio ill&atail;, quæ cum aliqua violentia efficitur.

PROP. XXXVIII.

Eitet in a&longs;cen&longs;u ligni por aquam violentia aliqua inter­cedat, nihilominùs operatio tota naturalis erit.

HOc autem pote&longs;t confirmari hac ratione; &longs;i verum e&longs;&longs;et, quòd quælibet operatio in qua violentia aliqua adhibetur reputari deberet non naturalis, &longs;e­queretur quòd alterationum corporum concretorum pariterque omnium generationum vegetabilium, & animalium nulla e&longs;&longs;et, neque vocari po&longs;&longs;et operatio naturalis, eò quòd &longs;emper requiritur actio, & pa&longs;­&longs;io qualitatum, & corruptio præcedentis &longs;ub&longs;tantiæ. Nec tamen dubitandum e&longs;t pa&longs;&longs;iones prædictas, & corruptiones, operationes e&longs;&longs;e violentas, non &longs;pon­te, &longs;ed cum di&longs;plicentia, & pa&longs;&longs;ione quadam factas, igitur in omnibus prædictis operationibus natur&atail; ip&longs;a violentiam exercet, & propterea confitendum e&longs;t proprium in&longs;titutum naturæ e&longs;&longs;e violentiam exer­cere, ita vt &longs;ine ip&longs;a nil prorsùs efficere &longs;ciat, neque &longs;uos fines con&longs;equi valeat.

Sed in&longs;tant, accidentale e&longs;&longs;e, vt natura de&longs;truat præ­cedentem formam, cùm &longs;ub &longs;equens minimè generari po&longs;&longs;it per&longs;euerante prima, & proindè, inquiunt, pri-mò, & per &longs;e naturam agere proptèr bonum, & prop­tèr finem, generationemque, & proindè præcedens corruptio erit veluti quædam conditio &longs;ine qua &longs;ub­&longs;equens forma introduci, ac generari non pote&longs;t; fa­tentur ergo, quòd &longs;altèm per accidens, natura actio­nes violentas exercet, &longs;ed ea omnia quæ à natur&atail; operantur, vocantur naturales actiones, igitur violen­tia illa accidentalis, qua forma præcedens de&longs;trui­tur, erit quoque vera actio, & operatio naturalis, quan­doquidem, ex vulgato axiomate, qui vult finem, velit quoque nece&longs;sè e&longs;t media illa, quæ ad finem condu­cunt, igitur naturalis in&longs;tinctus, quo formæ genera­tio qu&ecedil;ritur, con&longs;equiturquè, nece&longs;&longs;ariò inuoluit vio­lentiam, &longs;altem vt medium nece&longs;&longs;arium requi&longs;itum. Hinc deducere licèt non e&longs;&longs;e ab&longs;urdum, nec indecens, quòd natura violentiam aliquam exerceat, vt ea me­diante alia maior ab ona con&longs;equatur. Si hoc, inquam, verum e&longs;t in alterationibus, & corruptionibus, mul­tò magis hoc verificabitur in alijs &longs;uauioribus natu­ræ actionibus, quando corpora naturalia ad &longs;ua loca perducuntur propter bonum, & commoditatem eo­rumdem corporum violenter agitatorum, non &longs;ecùs, ac &longs;i quis curru, vel lectica è foro domum veheretur ineptè quidem de coactione, & violentia quereretur, cùm eiu&longs;modi violentia vtilitatem iucunditatemque ei afferret. Eodem penè modo à grauibus naturaliter de&longs;cendentibus perducerentur leuia ad debitu&mtail; &longs;itum.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XXXIX.

Violentia, qua lignum, & aer per aquam a&longs;cendit, dicitur naturalis, quia e&longs;t nece&longs;&longs;aria.

ET hæc quidem dicta &longs;untiuxtà vulgarem Peri­pateticam &longs;ententiam, &longs;ed qui&longs;quis hoc nego­tium attentè perpenderit, is planè percipiet, quòd vox violen tiæ trahit originem metaphoricè ab illo &longs;en&longs;u di&longs;plìcentiæ doloris, & amaritudinis, quam patiuntur animantia, dum alterantur, & corrum­puntur. Hinc &longs;equitur, quòd vbi deficit &longs;en&longs;us, defi­ciat quoque dolor, & violentia nece&longs;sè e&longs;t, & proin­dè alia regula, & norma certiori, ac tutiori di&longs;tingui deberent operationes naturales à non naturalibus, &longs;eù violentis, e&longs;tque huiu&longs;modi: operationes omnes quæ ab&longs;olutè, & omninò nece&longs;&longs;ariæ &longs;unt, neque vllo pacto fieri pote&longs;t, vt Natura eas negligat, &longs;ed cogi­tur nece&longs;&longs;ariò eas exercere, iure naturales operatio­nes appellari, ac cen&longs;eri debent. Modò quia ope­ratio naturalis, qua corpora grauiora profundiùs de&longs;cendunt, atque centro terræ propinquiora fiunt, quàm minùs grauia nece&longs;&longs;ariò &longs;ecum inuoluit ordi­natam di&longs;po&longs;itionem corporum, vt nimirùm grauio­ra infimum locum po&longs;&longs;ideant; minùs grauia verò &longs;u­premum, & in&longs;uper vniuer&longs;a huiu&longs;modi recta di&longs;po­&longs;itio exigit vt ambo corpora moueantur tendendo deorsùm in centro communi grauitatis eorum. Non &longs;ecùs ac in libra pre&longs;&longs;a ab in æqualibus ponderibus, a&longs;cen&longs;us minoris ponderis factus à de&longs;cen&longs;u corpo­ris grauioris alteram lancem prementis, ineptè qui­dem, & iniuria violentia appellatur; propterea quòd huiu&longs;modi operatio, ac di&longs;po&longs;itio nece&longs;&longs;aria, ac na­turalis e&longs;t.

Prop. 1.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Idip&longs;um, vel quid &longs;imile, dici debet de extru&longs;ione cuiuslibet corporis minùs grauis facta à pre&longs;&longs;ion&etail; ambientis fluidi grauioris, quia in tali ca&longs;u (vt &longs;uolo­co o&longs;tenditur) ade&longs;t libra quædam imaginaria per­petua, cuius centrum grauitatis &longs;ucce&longs;&longs;iuè deprimi­tur, & prædictum de&longs;censum nece&longs;&longs;ariò con&longs;equitur mo­tus &longs;ublimationis corporis minùs grauis, hocque tam diù per&longs;euerat, quou&longs;que efficiatur æquilibrium. Cum igitur &longs;it effectus nece&longs;&longs;arius, & naturalis, extru&longs;io, &longs;eù a&longs;cen&longs;us ligni quotie&longs;cumque circumdatur à flui­do grauiori, non pote&longs;t, nec debet prædictus a&longs;cen­&longs;us nuncupari, vel reputari violentus, quod erat o&longs;ten­dendum. Hoc confirmari pote&longs;t ex Galilei pulcher­rimo ratiocinio.

Prop. 9.

PROP. XL.

Motus a&longs;cen&longs;us grauium non minùs naturalis e&longs;t, quàm de&longs;cen&longs;us eorundem.

FInge globum no&longs;træ terræ perforari puteo percen­trum exten&longs;o v&longs;que ad Antipodas producto, at­que in hoc demi&longs;&longs;a pila ferrea proculdubio natura­lis eius grauitas &longs;ucce&longs;&longs;iuè maiorem impetum acqui­ret, quòu&longs;que ad centrum terræ pertingat, & vniuer-&longs;a hæc motionaturalis cen&longs;ebitur, eò quòd pendet à &longs;uo intrin&longs;eco principio grauitatis; &longs;ed no&longs;tqua&mtail; pila terræ centrum attingit profectò ibinon quie&longs;cet; nam impetus in præcedenti de&longs;cen&longs;u acqui&longs;itus pi­lam tran&longs;portabit vltra centrum, excurretque versùs Antipodas. modò in hoc excur&longs;u cùm pila à centro terræ recedat, procùl dubio &longs;ur&longs;um a&longs;cendet vocatur­que prædictus a&longs;cen&longs;us violentus motus, & contr&atail; eius naturam, & tamen ab operatione naturali de­&longs;cen&longs;us dependet.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Idip&longs;um alijs exemplis, quæ facilè po&longs;&longs;unt expe­riri, confirmari pote&longs;t.

Sit vas aqua plenum RSXV & ha­beatur quoque cylindrus ligneus EF, qui in aqua demer&longs;us non de­mergetur integrè infra &longs;upremam li­bellam aquæ RS, &longs;ed remanebit ali­qua eius pars GE eminens &longs;upr&atail; aquæ libellam, propterea quòd li­gnum minùs graue e&longs;t &longs;pecie, quàm ip&longs;a aqua, (vt Archimedes ait.) Si po&longs;tea eumdem ligneum cylindrum extra aqua&mtail; &longs;ubleuauero v&longs;que ad &longs;itum AB, & hinc liberè eum de&longs;cendere permittam, is profectò non con&longs;i&longs;tet, ne­què quie&longs;cet in &longs;itu EF, nam impetus acqui&longs;itus in de­&longs;cen&longs;u per aerem profundiùs infra aquæ libella&mtail; motu violento cylindrum immittet v&longs;que ad &longs;itu&mtail; CD & hinc denuò a&longs;cendendo tran&longs;gre&longs;&longs;o &longs;itu æqui­librij EF re&longs;iliet omninò extra aquam propè &longs;itu&mtail; AB, & &longs;ic denuò quou&longs;que repetitis vibrationibus &longs;en&longs;im languendo, tandèm quie&longs;cat in &longs;itu naturali EF.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Pari modo &longs;umpto fune-pen­dulo AB quod moueri po&longs;&longs;it circa &longs;uum centrum firmum A, remota pila plumbea. B à &longs;itu &longs;uo naturali, &longs;eu perpendicu­lari ad horizontem, perducta­que ad &longs;itum eleuatum C, illa planè vt grauis excur­ret de&longs;cendendo arcum CB, & vniuer&longs;us is motus na­turalis erit, vtpotè dependens ab impetu grauitatis intrin&longs;eco, non tamen in infimo &longs;itu B pila per&longs;i&longs;tet po&longs;tquam ibidem perducta e&longs;t, &longs;ed vlteriùs excur­ret ferè æquali &longs;patio priori vltrà perpendiculum v&longs;­que ad &longs;itum D, a&longs;cendendo nimirùm ab infimo &longs;itu B per integrum arcum BD, & quia motus ille qui gi­gnitur à principio intrin&longs;eco, & naturali non pote&longs;t e&longs;&longs;e non naturalis, cùmque a&longs;cen&longs;us pilæ vltra cen­trum terræ, & de&longs;cen&longs;us cylindri EF infra aquæ li­bellam po&longs;t ca&longs;um, & a&longs;cen&longs;us pilæ plumbeæ per ar­cum BD pendeat, creeturque ab illa naturali virtu­te grauitatis nempè eiu&longs;dem corporis de&longs;cendentis quatenùs de&longs;cendit: nulla enim alia cau&longs;a extrin&longs;e­ca &longs;uperueniens excogitari pote&longs;t, quæ violentia&mtail; in&longs;erat, & &longs;ursùm impellat prædictum graue, quàm impetus acqui&longs;itus, & conceptus in ip&longs;o ca&longs;u natura­litèr facto productoque à principio intrin&longs;eco graui­tatis eius, qui procùl dubio impetus à naturali prin-cipio pendens naturalis, & intrin&longs;ecus quoque erit, igitur etiam illa operatio a&longs;cen&longs;us erit naturalis qua­tenùs pendet creaturque à principio intrin&longs;eco, i&ntail; eo enim &longs;olummodò ca&longs;u violenta cen&longs;eri po&longs;&longs;et quan­do à peregrino, & aduentitio principio procrearetur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Contra hoc ratiocinium in&longs;urgit in&longs;ignis Peripa­teticus, & ait, quod &longs;ub&longs;equens a&longs;cen&longs;us vltra cen­trum terræ, vel vltra perpendiculum per arcum BD non pendet, nec procreatur à grauitate eiu&longs;dem cor­poris, &longs;ed ab impetu concepto per motum de&longs;cen&longs;us, qui impetus, inquit ille, res e&longs;t, toto cœlo diuer&longs;a à grauitate, imò prædictus impetus contra grauitatem luctatur.

Obiectiones recentioris authoris af­feruntur.

Patet ergò concedere aduer&longs;arium pilæ a&longs;cen&longs;um po&longs;t excur&longs;um vltra centrum, vel vltra perpendicu­lum effici, ac produci à virtute impetus impre&longs;&longs;i, qui nimirùm immediata cau&longs;a, & principium e&longs;t prædi­cti a&longs;cen&longs;us, &longs;eù operationis, quæ nomine leuitatis in&longs;ignitur. At quia præter immediatam cau&longs;am illius a&longs;cen&longs;us, &longs;cilicèt præter impetum, adnotari præte­rea debet cau&longs;a productrix prædicti impetus, quæ e&longs;t grauitas naturalis, & intrin&longs;eca eiu&longs;dem corpo­ris, ergo hæc erit cau&longs;a &longs;altèm mediata illius po&longs;tre­mi a&longs;cen&longs;us, & hìc noto quod aduer&longs;arius non negat, nec affirmat grauitatem fui&longs;&longs;e cau&longs;am, & principium productiuum prædicti impetus, &longs;ed tantummodò ait valdè differre grauitatem ab impetu, imò naturas contrarias, & &longs;e mutuo de&longs;tructiuas habere, quia ni­mirùm non alia de cau&longs;a ce&longs;&longs;at &longs;ub&longs;equens motus a&longs;cen-&longs;us tùm pilæ, tùm fune-penduli, ni&longs;i quia grauitas pi­læ contrario ni&longs;u vim impetus a&longs;cendentis de&longs;truit.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sed quid tandem hinc aduer&longs;arius deducere vel­let? an quia ex eo, quòd natura grauitatis diuer&longs;&atail; &longs;it ab impetu dicemus impetum prædictæ pilæ de­&longs;cendentis v&longs;que ad centrum, vel perpendiculum ge­nitum non fui&longs;&longs;e à vi, & exercitio grauitatis? à qu&atail; nam ergo virtute tamquam à principio immediato genitus fuit? profectò &longs;i &longs;en&longs;us negare non velimus, fatendum e&longs;t à nulla alia cau&longs;a, vel principio exter­no, &longs;ed tantummodò ab ip&longs;amet grauitate pilæ de­&longs;cendentis impetum prædictum genitum fui&longs;&longs;e, nec certitudo &longs;en&longs;us relinqui debet propter difficulta­tem adductam ab aduer&longs;ario, vt præclarè Ari&longs;toteles præcipit. Si igitur grauitas pilæ e&longs;t &longs;altem principium, & cau&longs;a mediata con&longs;equentis a&longs;cen&longs;us, nece&longs;&longs;ariò actus, & operatio a&longs;cen&longs;us, quæ violenta, & præter naturam &longs;axi exi&longs;timatur, efficietur procreabiturque ab interno, & naturali principio grauitatis eius, & proindè actus a&longs;cen&longs;us, &longs;eu motus violentus efficie­tur à principio interno, & naturali.

5. phy&longs; c. 3.

Et hìc obitèr mirari licèt horum philo&longs;ophoru&mtail; fecuritatem; hìc negant impetum à grauitate pro­creari, & inculcant valdè inter &longs;e differre, & &longs;e mu­tuò de&longs;truere, & vnà cum Ari&longs;totele in mechanicis a­pertè fatentur impetum e&longs;&longs;e grauitatem fluentem e&longs;­&longs;eque pror&longs;us eiu&longs;dem naturæ, quia nimirum &longs;axum impetu affectum comprimit, conterit aduer&longs;a cor­pora eodem modo, ac ingens pondus efficit.

Quæ&longs;t. 19.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sed in&longs;tat aduer&longs;arius quomodo pote&longs;t grauitas efficere impetum quo pila a&longs;cendit &longs;i videmus motum prædictum a&longs;cen&longs;us &longs;en&longs;im debilitari, & tandem ex­tingui &longs;olummodo propter renitentiam, & contra­riam actionem, quam efficit pondus eiu&longs;dem pilæ? Et hìc aio, quòd exercitium eiu&longs;dem ponderis, &longs;cili­cèt compre&longs;&longs;io eius producit duos effectus contra­rios, primò per de&longs;cen&longs;um creat, fouet, & auget im­petum eius, po&longs;teà per a&longs;cen&longs;um ei contranititur, debilitat, atque de&longs;truit eum, & licèt hoc mirabil&etail; videatur, nihilominùs idip&longs;um concedant nece&longs;sè e&longs;t, velint, nolint, cùm &longs;en&longs;u con&longs;tet, &longs;ic eadem manus impellendo &longs;axum dum deorsùm decidit, auget mul­tiplicatque eius impetum, at &longs;i &longs;axum &longs;ursùm a&longs;cen­deret eadem manus contrario motu impetum eius debilitaret, atque de&longs;trueret. &longs;imilitèr idem calor Solis generat, & auget plantas, & po&longs;tea eas exic­cat extinguitque. Ex his ergò patet in&longs;ufficienti&atail; &longs;uperiùs adducti ratiocinij.

PROP. XLI.

Ab eodem principio grauitatis a&longs;cen&longs;io, & &longs;ubleuatio cor­porum leuium effici pote&longs;t.

SEd redeo iam ad propo&longs;itum, & alia ratione ean­dem propo&longs;itionem per&longs;uadere conabor. Vul­gati&longs;&longs;imum axioma omnium philo&longs;ophorum e&longs;t, quòd natura &longs;emper producit &longs;uas operationes via bi eui&longs;­&longs;ima, &longs;ummo compendio, atque abhorret à prolixi-

tate, & multiplicitate cau&longs;arum quando &longs;uos effe­ctus producere pote&longs;t via illa breuiori, & faciliori. hinc deducitur, quod &longs;i po&longs;&longs;ibile e&longs;t tran&longs;portare cor­pora naturalia ad propria loca mediante vnica, & &longs;in­gulari motiua virtute grauitatis, vani&longs;&longs;imè, & &longs;tultè natura ageret, &longs;i niteretur prædictum finem a&longs;&longs;e qui adhibitis duobus principijs &longs;cilicèt grauitate, & al­tera oppo&longs;ita virtute, quæ leuitas nuncupatur. Quod verò po&longs;&longs;int naturalia corpora ad &longs;ua naturalia loca perduci à grauitate &longs;ola ab&longs;que leuitate patet ex &longs;u­periùs dictis, nam minor grauitas, quæ ve&longs;icæ aer&etail; plenæ tribuitur, & maior aquæ, & omnium maxima hydrargyro, &longs;ufficienti&longs;&longs;ima cau&longs;a e&longs;t apta ad produ­cendum prædictum effectum, quod deducitur ex prin­cipijs, & rationibus mechanicis. Quaproptèr pro­babili&longs;&longs;imè concedendum e&longs;t &longs;olo principio grauita­tis ab&longs;que vlla leuitate naturam &longs;uum finem a&longs;&longs;equi collocandi corpora terrena in debitis locis, nempè &longs;ursùm, & deorsùm.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 2.

Et hactenùs adductæ &longs;unt rationes probabiles con­tra po&longs;itiuam leuitatem, re&longs;tat modò vt idip&longs;um di­rectè o&longs;tendatur rationibus magis conuincentibus, & efficacioribus.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XLII.

Et primò o&longs;tendemus, quòd quodlibet corpus à principio in­trin&longs;eco, & naturali&longs;ponte translatum faciliùs, & celeriùs mouebitur in fluido rariori, & tenuio­ri, quàm in medio fluido cra&longs;&longs;o, & tenaciori.

SInt duo va&longs;a GHIK, alterum KILM, primum aqua repleatur, &longs;ecundum verò hydrargyro, immer­gatur verò eadem pila lignea A in vtroque fluido, in­telliganturque duæ moles &longs;patiales ex prædictis flui­dis B, & C, quæ æquales &longs;int ip&longs;i A, eique &longs;uperincun­bant, patet ergò quòd mercurij moles C grauior re­&longs;i&longs;tentior, den&longs;ior, atque compactior e&longs;t, quàm &longs;it

moles aqu&ecedil; B. præterea pila lignea A nullo pacto a&longs;cendere &longs;ursùm po­te&longs;t, ni&longs;i aquam B, ab eius loco ex­pellat vt ei locum cedat, atque mo­les ip&longs;ius ligni A transferatur ad oc­cupandum &longs;patium ei æquale B, & hoc &longs;emper contingit, vbique enim in a&longs;cen&longs;u cogitur continuato ni&longs;u &longs;ursùm impellere incumbentem a­quæ molem ei æqualem, tenacita­temque eius penetrare, ponatur iam gradus natura­lis impetus leuitatis ip&longs;ius ligni e&longs;&longs;e D, quia verò cor­pus motiuum A impetu D affectum impellit corpus B fluidum, quod in quiete con&longs;titutum &longs;ua naturali inertia re&longs;i&longs;tit impul&longs;ui impellentis corporis leuis A; ergò ex demom &longs;tratis in libro de vi percu&longs;&longs;ionis eadem vis motiua leuitatis ip&longs;ius A communicatur, & expan­ditur per vniuer&longs;um corpus motum, &longs;cilicèt per flui­dum B, igitur eius impetus D valdè debilitatur re­tardaturque, &longs;itque diminuta velocitas E, qua ni­mirùm lignum leue A, & fluidum B mouentur. pari ratione &longs;it F velocitas retardata, qua idem lignu&mtail; A nec non moles hydrargyri C &longs;ibi æquali agitatur. O&longs;tendendum e&longs;t quòd velocitas, E qua nimirum li­gnum a&longs;cendit per aquam maior &longs;it velocitate F quà lignum per mercurium eleuatur, & habere veloci­tatem E ad F reciprocè ferè eamdem proportionem,
quam habet corporea &longs;ub&longs;tantia AC ad corpulentiam AB. Quia ab eadem virtute motiua impelluntur duo corpora A, & B à qua priùs in­telligebatur moueri &longs;ingularis ma&longs;­&longs;a lignea A cui naturalis gradus impetus D conueniebat, igitur mo­les corporea, & materialis duorum corporum &longs;imul &longs;umptorum A & B ad molem corpoream A reciprocè eamdem proportionem habebit, quam eorum ve­locitates habent, & ideò erunt vt D ad E. Simili ratio­cinio vt moles corporea A ad molem corpoream AC ita e&longs;t velocitas F ad D, ergo ex æqualitate pertur­bata corporea &longs;ub&longs;tantia AB, ad AC eamdem pro­portionem habebit, quàm velocitas F ad E, e&longs;t qu&etail; &longs;ub&longs;tantia corporea AB minor ea quæ continetur in AC, ergò impetus F minor e&longs;t quàm E; quaproptèr lignum A intrà mercurium C translatum &longs;ursùm a&longs;cen­dere debet tardiori, & minori velocitate, quàm &longs;it velocitas E, quæ competit ligno a&longs;cendenti in aqua B.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

De vi per­cu&longs;&longs;ionis pro po&longs;it. 15.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Et profectò euidenti&longs;&longs;imum e&longs;t, quòd quodlibet corpus à principio intrin&longs;eco motu &longs;pontaneo trans­latum, multò faciliùs gradietur excurretque per me­dium fluidum rarius, & cedens, quàm in medio flui­do tenaciori, & cra&longs;&longs;iori, vt pila aurea celeriùs per aerem, quàm per aquam eiu&longs;dem &longs;patij de&longs;cendit, & per aquam velociori motu, quàm per mercurium ex­currit; &longs;ic paritèr videmus animalia, quæ intrin&longs;ec&atail; vi mouentur, difficiliùs gradi po&longs;&longs;e, &longs;i infra arena&mtail; &longs;ub mergantur, & minùs difficilè infrà lutum, & fa­ciliùs in aqua, & multò faciliùs in aere, nec vnquam contrarium contingere poterit, quòd nimirùm idem animal eamdem vim motiuam exercendo difficiliùs & tardiùs moueatur per aerem, quàm per aquam, & difficiliùs per aquam, quàm per lutum, aut per hy­drargyrum.

PROP. XLIII.

Non moueri &longs;ursùm corpora, quæ leuia appellantur, à vi intrin&longs;eca leuitatis.

HIs po&longs;itis con&longs;ideremus modò ceram, aut ve&longs;i­cam aere plenam a&longs;cendentem per diuer&longs;a me­dia fluida, &longs;i verum e&longs;t, quòd aerea ve&longs;ica &longs;ursùm a&longs;cen-dit in aqua; authydrargyro motu &longs;pontaneo, nempè ab intrin&longs;eca virtute motiua, quæ vocatur leuitas, igitur nece&longs;sè e&longs;t vt in a&longs;cen&longs;u penetret corpora flui­da intermedia; atque eorum tenacitatem, & den&longs;i­tatem &longs;uperet, imò fluidum è &longs;uo loco expellat, vt via, & tran&longs;itus paretur, qua &longs;ursùm a&longs;cendere, & perduci po&longs;&longs;it, & quia hydrargyrum magis con&longs;ti­patum, den&longs;um, & graue e&longs;t, quam aqua, igitur quod­libet corpus leue aere repletum, aut aeris natura&mtail; participans, vt lignum, & cera, (quæ ex aduer&longs;ario­rum &longs;ententia mouentur ab intrin&longs;eca virtute leui­tatis) nece&longs;sè e&longs;t vt maiorem re&longs;i&longs;tentiam offendant in tran&longs;itu per hydragyrum, à cuius tenacitate, den­&longs;itate, & pondere gradus impetus eius nece&longs;&longs;ariò re­tunditur retardaturque multò magis, quàm in a&longs;cen­&longs;u per aquam contingit, quæ cùm magis rara, & ce­dens &longs;it, minùs debilitat retardatque eamdem eius vim motiuam, quaproptèr motus a&longs;cen&longs;us ligni, vel ceræ per hydrargyrum multò magis retardabitur, quàm ille, qui per aquam fit; quia verò hoc e&longs;t fal­&longs;um, & contra &longs;en&longs;us euidentiam, multò enim velo­ciòr e&longs;t motus ligni, vel ceræ factus per hydrargyrum, quam per aquam; non igitur verum e&longs;t ab intrin&longs;eco, & natu­rali principio &longs;ursùm moueri, & proindè cau&longs;a a&longs;cen­&longs;us non erit leuitas po&longs;itiua, ideoque nullum v&longs;u&mtail; habebit in natura, nec propterea exi&longs;tet vlla leuitas.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XLIV.

Ratione mechanica à grauiori fluido celeriùs idem mobile &longs;ursùm exprimitur, quàm à fluido minùs graui.

HViu&longs;modi difficultates omninò vitantur effu­giunturque, &longs;i certitudinem, & nece&longs;&longs;itatem ex principijs mechanicis pendentem &longs;equamur, &longs;ci­licèt po&longs;ita &longs;olummodò grauitate in omnibus cor­poribus &longs;ublunaribus; nece&longs;sè e&longs;t vt graui&longs;&longs;imum flui­dum hydrargyri maiori impetu &longs;ursùm per extru&longs;io­nem impellat lignum, quàm aliud fluidum minùs gra­ue, vt e&longs;t aqua, &longs;icuti in bilance pondus vnius vnciæ maiori velocitate &longs;ursùm impellitur à maiori pre&longs;­&longs;ione contraria ponderis decem librarum, quàm à minori compre&longs;&longs;ione ponderis vnius libræ. Demon­&longs;tratio verò huius rei &longs;uo loco exponetur, &longs;ed inte­rim &longs;i effectus omnes qui ob&longs;eruantur in hi&longs;ce corpo­ribus a&longs;cendentibus ijdem prorsùs &longs;unt, & ij&longs;de&mtail; legibus mechanicis fiunt, ac &longs;i omnia corpora gra­uia fui&longs;&longs;ent, &longs;ed inæquali grauitate donarentur, & præterea in ijs non apparet phenomena motus &longs;ieri earatione, quæ requireretur &longs;i præter grauitate&mtail; reperiretur quoque aliud principium contrarium le­uitatis: igitur concedendum e&longs;t &longs;ola grauitate natu­ram operari, neque leuitatem vllam exigere.

Contra euidentiam harum rationum non de&longs;unt, qui difficultates, & &longs;ubterfugia afferant pro retinen­da &longs;uæ po&longs;itionis inueri&longs;imilitudine; aiunt enim li-gnum tardiùs in hydrargyro a&longs;cendere debui&longs;&longs;e; quàm per aquam ob maiorem illius re&longs;i&longs;tentiam; &longs;ed propter contrarietatem, & inimicitiam, quam habet lignum cum Mercurio, &longs;uum cur&longs;um accelerat vt ex­peditè mercurium fugiat, & aquam aeremque a&longs;&longs;e­quatur; quod symbolum elementum, atque amicum e&longs;t; & propterea ce&longs;&longs;ante odio non cogitur celerri­mè ab eo di&longs;cedere. Sed vide quàm faciles &longs;int præ­dicti philo&longs;ophi; qui occa&longs;ione exigente non veren­tur alitèr re&longs;pondere, nam &longs;i ego quæram, quare gra­uitas, quæ cortè ine&longs;t in hi&longs;ce terrenis corporibus, celeriùs transfert &longs;axum, quò magis ad terram acce­dit, atque ei approximatur; re&longs;pondent quia vicinia terræ velutiroboratur vis motiua &longs;axi cadentis; &longs;ic paritèr leuitas ve&longs;ic&ecedil; aere&ecedil; cre&longs;cere deberet in aqu&ecedil; &longs;ummitate, quia nempè aeri approximatur, & ideò virtus eius motiua roborari quoque deberet. Sed his omi&longs;&longs;is &longs;ummi po&longs;&longs;unt diuer&longs;a corpora, quæ na­turam, & temperiem diuer&longs;am, & contrariam aquæ habeant, &longs;imillimam verò mercurio, & talis forta&longs;&longs;e erit am pulla vitrea, vel ve&longs;ica, quæ repleatur mercu­rio &longs;ublimato, vel pr&ecedil;cipitato; &longs;ic quoque vas &longs;ieri po&longs;&longs;et ex metallo, vel alio corpore &longs;rmillimo hy­drargyro, vt nimirùm efficiatur compo&longs;itum cuius natura valdè diuer&longs;a &longs;it ab aqua, & &longs;imillima hydrar­gyro, & &longs;ic omninò tolleretur inimicitia, & antipa­thia inter vas, & fluidum cra&longs;&longs;ius mercuriale, nihi­lominùs ob&longs;eruabitur prædictum vas velociùs a&longs;cen­dere per hydrargyrum, tardo verò motu per aquam, igitur illa &longs;omniata inimicitia non erit cau&longs;a prædi­ctæ inæqualitatis motus, &longs;ed mechanica, & naturalis nece&longs;&longs;itas, qua maximum pondus hydrargyrj impe­tuo&longs;iore motu exprimit, & impellit &longs;ursùm conten­tum vas vitreum, vel ve&longs;ica, quàm impellere aqu&atail; queat &longs;uo minori pondere.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Recurrunt aduer&longs;arij ad maiorem ini micitiam quam habet lignum, &longs;eu aer cum hydrargyro, quàm cum aqua, vt de­ducant cele­riùs lignum fugere mer­curium, quam aquam debere.

Sed reijci­tur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Id ip&longs;um alijs exemplis confirmari po&longs;&longs;et, &longs;i nimi­rum &longs;umatur oleum à frigore conden&longs;atum, & gla­ciatum, cuius temperies, & natura potiùs grauiori mercurio, vel oleo tartari a&longs;&longs;imilatur, & è contr&atail; contrariam naturam, & diuer&longs;am haberet ab ip&longs;&atail; aqua, & &longs;ic oleum prædictum ob amicitiam lento motu a&longs;cendere deberet per hydrargyrum, aut per oleum tartari. Sed celerrimè in aqua currere debe­ret, vtpotè oleo contraria. Similitèr calx in ve&longs;ica con­tenta aqu&ecedil; forti &longs;imillima e&longs;t ob caliditatem, & acredi­nem ambarum, & è contrà &longs;ummè contraria erit con­muni aquæ, & nihilominùs in illa veloci&longs;&longs;imè a&longs;cen­dit, in hac tardè. Similitèr &longs;umi po&longs;&longs;ent va&longs;cula ex cera, aut bitumine, quæ repleri po&longs;&longs;ent puluere, &longs;pi­ritu, oleo, velvino, vel alijs innumeris rebus, quæ &longs;emper a&longs;cendent veloci&longs;&longs;imè in fluidis grauioribus, vt &longs;unt aquæ regiæ, licèt in &longs;umma caliditate, & acre­dine &longs;alina conueniant, & è contra languido, & tar­do motu in fluidis contrariæ naturæ a&longs;cendunt, dum­modò minùs grauia &longs;int. Quaproptèr verum non e&longs;t ob inimicitiam, & contrarietatem ve&longs;icam aerea&mtail; veloci&longs;&longs;imè à mercurio fugere, & languido motu ex­currere per aquam ei &longs;imilem, &longs;ed potiùs ob mecha-nicam rationem de&longs;umptam à maiori, vel minori gra­uitate, quæ deducitur ex Archimedis doctrina, quòd &longs;cilicèt fluidum grauius per extru&longs;ionem impeller&etail; &longs;ursum debeat corpora minùs grauia, & hæc e&longs;t cau&longs;a, quare ab&longs;que po&longs;itiua leuitate corpora &longs;ursùm a&longs;cen­dere debent.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Contra per&longs;picuitatem &longs;upradicti ratiocinij obijciunt primò, quòd &longs;icuti grauiora intra minùs grauia mer&longs;a fe­runtur deorsùm tanta vi, quæ &longs;it æqualis differentiæ gra­uitatis mobilis &longs;upra grauitatem medij, constat euidentèr euenturum proportion alitèr in leuioribus intra minùs leuiacontentis ea &longs;cilicèt in ordine ad leuitatem, &longs;ursùm, non niti &longs;ecundùm men&longs;uram exce&longs;&longs;us &longs;upra minùs leue &longs;ursùm ni­&longs;ura, vt &longs;imilis ratio per&longs;uadet. Hoc &longs;uppo&longs;ito veluti cer­tum, & euidens re&longs;pondet argumento &longs;uperius addu­cto, aitque ex pirationem calidam re&longs;pectu aquæ valdè le­uem &longs;ecundùm men&longs;uram totius &longs;uæ leuitatis &longs;ursùm niti intra aquam, ac proindè valere ad re&longs;i&longs;tentiam illius cele­ricèr &longs;uperandam, at verò valdè exiguum exce&longs;&longs;um &longs;upra aerem obtinentem in leuitate &longs;ursùm niti præcisè &longs;ecundum men&longs;uram talis exce&longs;&longs;us, ac proindè non e&longs;&longs;e mirum &longs;i lentè per aerem a&longs;cendat etiam&longs;i dicatur à leuitate po&longs;itiua in­trin&longs;eca moueri.

Dennò ad­mi&longs;&longs;a leuita­te colligunt ignem cele­riùs per a quam, quam per aere&mtail; a&longs;cendere de­bere.

Itaque &longs;icuti nos ex Archimedis doctrina deduci­mus rationem de&longs;cen&longs;us grauium, & a&longs;cen&longs;us leuium ex hac &longs;uppo&longs;itione, quòd corpora omnia &longs;ubluna­ria &longs;int grauia, &longs;ibi per&longs;uadent demon&longs;trare po&longs;&longs;e ea­dem symptomata &longs;upponendo nedùm corpora a&longs;cen­dentia, &longs;ed etiam medium fluidum, in quo a&longs;cendunt e&longs;&longs;e leuia; quaproptèr quotie&longs;cumque agitur de cor­poribus grauibus de&longs;cendentibus comparari debent grauitates tum corporis mobilis, tùm medij fluidi in quo de&longs;cendit; at è contrà cum agitur de corporibus a&longs;­cendentibus, debent paritèr intèr &longs;e comparari le­uitates eorum vnà cum leuitate medij fluidi in quo a&longs;cendunt.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Modò vt fallacia huius ratiocinij detegatur, demon­&longs;trabo priùs lemmata aliqua mechanica, ex quibus pe&longs;tea adhibitis hypothe&longs;ibus &longs;upradictis demon­&longs;trabo impo&longs;&longs;ibile omninò e&longs;&longs;e vt impetus velocita­tis quo &longs;ursùm a&longs;cendunt corpora illa, quæ leuia ap­pellantur, produci po&longs;&longs;it atque dependeat à princi­pio aliquo intrin&longs;eco à quo &longs;ursùm impellantur re­moueanturque à centro terræ.

Et primo loco ob&longs;eruo cum Ari&longs;totele in mecha­nicis, quòd.

PROP. LXV.

Libræ, vel rotæ termini oppo&longs;iti contrarijs motibus circa centrum agitari debent.

SIt libra radiorum æqualium, vel rota AIBH con­uertibilis circa &longs;uum centrum C, hic manife&longs;tum e&longs;t, quòd &longs;i libram, aut rotam re uoluere velimus, ita

vt terminus eius A de&longs;cendat deorsùm percurrendo arcum AI nece&longs;sè e&longs;t vt eius oppo&longs;i­tus terminus B motu contrario &longs;ursùm a&longs;cendat percurrendo arcum BH æqualem contrapo­&longs;ito AI. Et quotie&longs;cumque præ­dicti motus contrarij &longs;imul fie­ri nequeunt, tunc nece&longs;sè e&longs;t vt libra, vel rota quie&longs;cati&ntail; eodem &longs;itu, nec agitetur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XLVI.

Si eidem libræ termino applicentur potentiæ ad oppo&longs;itas partes trahentes mutuo &longs;eimpedient, & potentia maior præualebit, libram flectendo vi æquali dif­ferentiæ potentiarum.

APponatur poftea pondus DE termino libræ A; hoc profectò vim efficit, conaturque traher&etail; terminum libræ A per directionem AD versùs cen­trum telluris, at quia &longs;emidiameter AC in centro libr&ecedil; figitur immobiliter, hinc con&longs;e quetur reuolutio libr&ecedil; fereturque terminus A non per lineam rectam AD, &longs;ed per arcum AI excurrendo integrum quadrantem, & quia libra AB &longs;upponitur continua, & rigida eodem tempore quo terminus A arcum AI pertran&longs;it oppo­&longs;itus eius terminus B de&longs;cribet contrapo&longs;itum arcum BH. Modò motum eiu&longs;dem libræ, & de&longs;cen&longs;um pon-deris DE impedire po&longs;&longs;umus, &longs;i eidem termino A ap­plicaretur vis contraria G, qu&ecedil; traheret &longs;ursùm eum ip­&longs;um terminum A per eamdem rectam lineam horizon­ti perpendicularem ver&longs;us &longs;upremum terminum G; & &longs;iquidem vis, & facultas motiua G æqualis e&longs;&longs;et vi ponderis DE, nulla ratio &longs;uadet quòd vna earu&mtail; virtutum reliquam &longs;uperet, aut vincat, proindequ&etail; terminus libræ A non de&longs;cendet versùs I, nec a&longs;cen­det versùs H, &longs;ed omninò quie&longs;cetin eodem &longs;itu. Si verò pondus DE &longs;uperaret vim motiuam G, eiu&longs;que exce&longs; &longs;us e&longs;&longs;et pondus E, tunc procùl dubio pondus DE præ­ualeret &longs;uperaretque vim motiuam G, & impetus, atque vis, à qua prædicta libra flecteretur deorsù&mtail; versùs I men&longs;uraretur à vi ponderis E, quæ e&longs;t diffe­rentia, &longs;eù exce&longs;&longs;us, quo pondus premens DE &longs;upe­rat vim eleuantem G.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XLVII.

Si oppo&longs;itos terminos libræ, vel rotæ duæ potentiæ traham, ambæ deorsùm tendendo, &longs;e mutuò impedient, & maior potentia præualebit, &longs;ed vi æquali differentiæ earum.

POte&longs;t deindè alia ratione prohiberi, & impediri de&longs;cen&longs;us ponderis DE ab&longs;que eò, quòd termi­no A applicetur vis aliqua animata contraria G, & hoc con&longs;equitur &longs;i applicetur termino oppo&longs;ito B aliud pondus F, quod dùm deorsùm impellit ad ea&longs;­dem partesad quas dirigitur pondus DE prohibetur quoque de&longs;cen&longs;us termini A eiu&longs;dem libræ, vt dictum e&longs;t; & &longs;iquidem pondus F æquale fuerit ponderi DE, tunc efficietur æquilibrium, quia dùm ambo pon­dera conantur de&longs;cendere deorsùm transferre qu&etail; duos terminos libræ versùs infimum &longs;ignum quadran­tis I, & hoc efficitur æquali vi, & impetu, procùl du­bio vna vis, & conatus impedit motum, & defcensum alterius, & ex hoc mutuo impedimento re&longs;ultat quies totius libræ in &longs;itu horizontali; at &longs;i pondus F æqua­Ie fuerit vni portioni D totius ponderis DE, tune præua lente maiori pondere deprimetter minum libr&ecedil; A versùs I, a&longs;cendetque oppo&longs;itus terminus B versùs H tanta vi quæ &longs;it æqualis exce&longs;&longs;ui ponderis E. Hinc colligitur quod in libra, vel rota duo æquales im­

petus ad ea&longs;dem partes tenden­tes, nempè deorsùm, ideoqu&etail; &longs;imiles inter &longs;e, &longs;e mutuo impe­diunt, & de&longs;truunt, itaut quies con&longs;equatur, &longs;i verò eorumdem &longs;imilium motuum de&longs;cendentium vires inæquales fuerint, præua­lebit maius pondus, libramque reuoluet non integra &longs;ua vi, &longs;ed tantummodò illa dif­ferentia, vel exce&longs;&longs;u, quo maius pondus &longs;uperat minus.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Prop. 45.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XLVIII.

Ii&longs;dem datis, &longs;i ambæ potentiæ &longs;ursùm trahant, idem &longs;equetur.

ID ip&longs;um verum quoque e&longs;t,

&longs;i applicentur terminis op­po&longs;itis eiu&longs;dem libræ A, B duæ vires inæquales, DE maior, & F minor, quæ ambæ &longs;ursùmter­minos libræ trahant a&longs;cenden­do. & hìc eodem modo o&longs;ten­detur, quòd libra flectetur &longs;ur­sùm ab A versùs H, & reliqua visminor F &longs;uperabitur ab ex­ce&longs;&longs;u virtutis DE &longs;upra F, de&longs;cendetque terminus B versùs I.

PROP. XLIX.

Si oppo&longs;itos terminos libræ duæ potentiæ trahant vna &longs;ur­sùm, altera deorsùm, &longs;e mutuò iuuabunt, & vis li­bram flectens æqualis erit &longs;ummæ ambarum potentiarum.

TErtio loco in eadem rota, &longs;eù libra AB termi­nus A deorsùm trahatur à pondere D, &longs;ed eius oppo&longs;itus terminus B &longs;ursùm trahatur à vi a&longs;cenden­te F, quæ minor &longs;it vi ponderis D, dico, quòd libra non quie&longs;cet, &longs;ed reuoluetur eius terminus A de&longs;cen-dendo versùs I, eleuabiturque terminus oppo&longs;itus B versùs H, & conatus, &longs;eù vis, quo libra reuoluitur æqualis erit non differentiæ, & exce&longs;&longs;ui ponderis D &longs;upra vim F, &longs;ed æquabitur aggregato ambarum vir­

tutum D, & F. Applicetur termi­no B pondus E æquale vi &longs;ursùm impellenti F, pariterque ibidem &longs;u&longs;pendatur aliud pondus G æqua­le oppo&longs;ito ponderi D, manife­&longs;tum e&longs;t (amotis, vel coercitis vi­ribus F, & E) quòd pondera æqua­lia D, & G pendentia à terminis radiorum æqualium eiu&longs;dem li­bræ efficient æquilibrium, & ideò libra quie&longs;cet. Præterea quia pondus E æquatur vi contrariæ &longs;ursùm trahenti F, & ambæ applicantur eidem termino B libræ AB (ab æqualibus ponderi­ribus D, & G æquilibratæ) igitur duo pondera &longs;imùl &longs;umpta G, & E libram impellunt contrario ni&longs;u, &longs;ci­licet à B ver&longs;us I, & præcisè adæquant conatum pon­deris D, & vim trahentem F, quæ ambo deprimere po&longs;&longs;unt terminum libræ A versùs I &longs;ubleuando ter­minum B versùs H. Ergo duævires D, & F &longs;imùl sump­ (amotis ponderibus G, & E) determinant vim, &longs;eù conatum, quo libra reuoluide bet ab A, versùs I.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Pr. 47.

Pr. 46.

Et hìc animaduertendum e&longs;t, quòd duæ vires D, & F, quæ reuerà contrariæ &longs;unt inter &longs;e (cum illa deor­sùm comprimat, hæc verò &longs;ursùm trahat) non &longs;ibi mutuò opponuntur, nec vna earum alteriùs motu&mtail; impedit, &longs;ed vna promouet, adiuuat, & auget cona­tum, vim, & impetum alterius; & hoc accidit quianon applicantur ambæ eidem termino A libræ, &longs;ed ter­minis oppo&longs;itis A, & B, qui iuxtà libræ, & rotæ pro­prietatem, & naturam debent moueri motibus con­trarijs, &longs;cilicèt A per arcum AI, & B per arcum BH. igitur impulfus ponderis D deorsùm, & tractio facta àvi F &longs;ursùm conueniunt, & &longs;e mutuò adiuuant, & augent, vt ab vtri&longs;que reuolutio libræ efficiatur, quæ ad ea&longs;dem partes impellitur ab ei&longs;dem viribus con­trarijs. ce&longs;&longs;et igitur admiratio quare duæ vires con­trariæ in libra &longs;e mutuò non de&longs;truant, &longs;ed potiùs mu­tuo &longs;e adiuuent, ita vt ex vtri&longs;que re&longs;ultet vna vis con­po&longs;ita, à qua libra reuoluitur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Prop. 45.

PROP. L.

Si oppo&longs;itos libræ terminos quatuor potentiæ trahant, duæ &longs;ursùm, & duæ deorsùm, conatus &longs;eù vis libram fle­ctens men&longs;uratur à &longs;umma differentiæ a&longs;cen­dentium, cum differentia de&longs;cendentium potentiarum.

SI tandem eadem libra à quatuor viribus impel­latur trahaturque, quarum duæ D, & G graues &longs;int deorsùmque tendant, duæ verò M, & F &longs;ursù&mtail; eo&longs;dem terminos libræ trahant, &longs;itque energia virtu­tis M maior quàm F, pondus verò D minus &longs;it quàm G, tunc manife&longs;tum e&longs;t, terminum

A eleuari &longs;ursùm versùs Hab ex­ce&longs;&longs;u quo vis M &longs;uperat faculta­temmotiuam F, & è contrà op­po&longs;itus libræ terminus B depri­metur deorsùm versùs I ab ex­ce&longs;&longs;u quo pondus G &longs;uperat vim grauitatis D; & quia prædicti duo impul&longs;us differentiales con­trarij &longs;unt, vnus quidèm &longs;ursù&mtail;, alter verò deorsùm, applicanturque terminis oppo&longs;i­tis eiu&longs;dem libræ; igitur &longs;e mutuo adiuuant promo­uenturque, & proindè conatus, vis, atque impetus, quo vniuer&longs;a libra reuoluitur, æqualis erit aggrega­to prædict arum differentiarum.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Prop. 49.

PROP. LI.

Vis motiua, qua &longs;olidum grauius &longs;pecie, quàm fluidum, de­&longs;cendit, æqualis est differentiæ ponderis &longs;olidi &longs;upra pondus fluidi ei æqualis mole.

HIs declaratis intelligatur vas RGS aqua plenum, in eoque immergatur corpus aliquod graue durum, ac con&longs;i&longs;tens DE, quod grauius &longs;it aqua collaterali F patet ex dictis prop. 9. & ex Archimede, duo pondera DE, & F collocari in libra quadam imaginaria, & perpetua AB in qua exce&longs;&longs;us ponderis &longs;olidi DE &longs;upra grauitatem aquæ F quæ &longs;it æqualis mole ip&longs;i DE, &longs;emper idem e&longs;t in quacumque aquæ profunditate &longs;olidum collocetur, &longs;itque pon­dus E exce&longs;&longs;us quo pondus DE &longs;uperat grauitate&mtail; aquæ F, igitur conatus, vis, & impetus, quo &longs;olidum DE de&longs;cendit infra aquam men&longs;uratur à vi ponderis E.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LII.

Vis motiua qua &longs;olidum leuius &longs;pecie, quàm fluidum a&longs;cen­dit æqualis est exce&longs;&longs;ui leuitatis &longs;olidi &longs;upra leuita­tem fiuidi ei æqualis mole.

E Contrà, &longs;i &longs;upponamus, quod lignum DE pari­terque aqua F careant grauitate, &longs;ed tantummo­ à vi leuitatis informentur, & ambo impul&longs;um, & impetum faciant &longs;ursùm conenturque a&longs;cendere, non &longs;ecùs o&longs;tendetur, quòd in libra, &longs;eù rota perpetua ligni DE maior leuitas præualebit &longs;uperabitque mi­norem leuitatem fluidi collateralis F, proindeque libra inflectetur ab A versùs R a&longs;cendendo tanta vi, quanta e&longs;t differentia, &longs;eù exce&longs;&longs;us E, quo leuitas li­gni &longs;uperat aquæ leuitatem.

PROP. LIII.

Vis motiua qua leue corpus in flnido graui a&longs;cendit æqualis e&longs;&longs;e debet &longs;ummæ lenitatis &longs;olidi, & grauitatis fluidi.

SI verò variata hypote &longs;i ponamus lingnum F leue, & &longs;ursùm ab intrin&longs;eco principio impelli, & mo-ueri, at ffuidum collaterale D, quòd &longs;it hydrargyrum &longs;upponatur deorsùm tantummodò vim exercere, vt exigit maxima eins grauitas, nec prorsùs &longs;ursùm im­

pellere, tunc quoque libra, &longs;eù rota perpetua efformabitur i&ntail; qua &longs;emperterminus B trahetur &longs;ursùm à po&longs;itiua leuitate ip&longs;ius ligni F a&longs;cendetque versùs R, terminus verò oppo&longs;itus depri­metur ab A versùs H vt natur&atail; grauitatis exigit, & quia hi duo motus, & conatus in oppo&longs;itis terminis libræ contrarij &longs;unt, ergò vici&longs;&longs;im &longs;e non de&longs;truunt, nec contrariantur, &longs;ed &longs;e mutuò fa­uent, & adiuuant. igitur conatus, & impetus quo re­uoluitur iam dictalibra, &longs;cilicèt quo lignum F a&longs;cen­dit à fundo mercurij æqualis erit non differentiæ, &longs;ed aggregato ex vileuitatis F, & ex facultate ponderis mercurij D.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LIV.

Si verò tam&longs;olidum, quàm fluidum exerceant leuitatem, atque grauitatem, vis motiua, qua vnum eorum ele­uatur æqualis e&longs;t aggregato ex differentia leui­tatum vnà cum differentia grauitatum earum.

TAndèm &longs;i &longs;upponamus, quod lignum vim faciat &longs;ursùm vt leue, & etiam eodem tempore gra­uitatem eius natiuam exerceat, pariterque aqua D in va&longs;e nedùm deorsùm comprimat, vt grauis, &longs;ed etiamnon omninò priuetur gradu aliquo leuitatis, tunc &longs;imilitèr libra perpetua imaginaria efformabi­tur in qua terminus I deorsùm impellitur ab exce&longs;&longs;u quo grauitas aquæ D &longs;uperat

grauitatem ligni F, & è contràter­minus B &longs;ursum eleuabitur|ab ex­ce&longs;&longs;u quo leuitas ligni &longs;uperat leuitatem ip&longs;ius aquæ. Et quia prædicti impul&longs;us &longs;unt contra­rij, applicanturque eidem li­bræ imaginariæ, igitur vnus impul&longs;us alteri non op­ponitur, & proindè vniuer&longs;alis conatus, & impetus prædictæ libræ, &longs;cilicèt vis, & impetus, quo lignum F a&longs;cendit in aqua men&longs;uratur ab vtroque exce&longs;&longs;u, &longs;cilicèt ab aggregato differentiæ ponderum aquæ, & ligni, vnà cum exce&longs;&longs;u leuitatis ligni &longs;upra aqueam leuitatem.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Prop. 50.

SVPPOSITIO V.

HIs præmi&longs;&longs;is &longs;upponamus cum aduer&longs;arijs pri­mo loco, quòd reuerà præter corpora graui&atail; etiam leuia in natura exi&longs;tant, quorum aliqua, vt ait Ari&longs;toteles, &longs;int &longs;implicitèr talia, alia verò re&longs;pectiuè, veluti ignis dicitur ab&longs;olutè leuis, & terra, &longs;eù hy­drargyrum, vel aliud fluidum æquè graue, ac ip&longs;&atail; terra e&longs;t appellabitur ab&longs;olutè graue reperiuntur po­&longs;tea alia corpora intermedia &longs;implicia, vel mixt&atail;, quæ vocantur grauia &longs;imùl, & leuia re&longs;pectiuè, &longs;cili-cèt aqua demer&longs;a intra mercurium dicitur leuis, & moueri &longs;ursùm à principio intrin&longs;eco, at &longs;i eade&mtail; aqua intra oleum mergatur, dicetur iam grauis, no&ntail; leuis, & moueri deorsùm à principio interno. Hoc verò duplicem &longs;en&longs;um habere pote&longs;t, aut dictæ duæ contrariæ qualitates &longs;emper in eodem corpore aquæ exi&longs;tunt, & vigent, aut &longs;ucce&longs;&longs;iuè modò vna, modò altera in ea reperitur, ita vt aqua in fundo hydrar­gyri po&longs;ita &longs;it reuera leuis, & nullo pacto grauis, & è contià, quando eadem aqua in oleo demergitur, hìc grauitatem habeat, & nullam prorsùs leuitatem, itaut remaneat &longs;opita, & extincta leuitas illa, quæ tanta efficacia aquam &longs;ursùm im pellebat à fundo mer­curij, igitur in primo &longs;en&longs;u retinere aqua deberet perpetuò duas contrarias qualitates, &longs;cilicèt leuita­tem, & grauitatem eodem modo, ac dicuntur mixta participare ex qualitatibus extremis, calido nempè, & frigido, & veluti colores medij nigre dinem, at­que albedinem participare censentur, igitur dici de­beret, quod in igne prorsùs, & ab&longs;olutè leui qua­tuor integri gradus leuitatis reperiuntur, & &longs;imili­tèr in ip&longs;a terra exi&longs;tunt quatuor gradus grauitatis, at aer habebit tres gradus leuitatis, & vnicum gra­dum pondero&longs;itatis, &longs;ic aqua vnicum gradum lèui­tatis, & tres grauitatis haberet, & tandèm aliud cor­pus medium inter aerem, & aquam, veluti for&longs;an e&longs;t &longs;piritus vini, habere po&longs;&longs;et duos gradus leuitatis, & duos alios gradus grauitatis.

[missing] 53.) conatus, & impetus totalis, quo ignis per mer­curium a&longs;cendit, velterra per ignem de&longs;cendit, men­&longs;urari debet ab aggregato virium extremarum, &longs;ei­licet à tota vi leuitatis cum tota vi grauitatis, quar&etail; totalis impetus erit octo graduum. Sed hoe e&longs;t fal­&longs;um, contra aduer&longs;arij a&longs;&longs;ertionem, & contra Archi­medem, ea enim, quæ in fluido cleuantur, tanta vi a&longs;cendunt, quanta e&longs;t grauitas qua moles flaidimer­curialis æqualis corpori igneo intra ip&longs;um demer&longs;o &longs;uperat huius grauitatem, quænulla e&longs;t, & proindè ignis impetu quatuor graduum per mercurium a&longs;cen­dit, quaproptèr non fertur ignis &longs;ursùm à vi eius le­uitatis, & ideò leuis non erit, quod erat &c.

Suppo&longs;itio­nes aliquperipateticrecentur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Dubitatur de men&longs;ura gradus præ­dicti impe­mus.

Sed in&longs;tabit denuò peripateticus, dicetque, quòd eavelocitas, quæ exercetur ab igne a&longs;cendente per mercurium, aut à terra de&longs;cendente perignem po­terit cen&longs;eri octo graduum, vel quatuor ad libitum, quia non habemus certam men&longs;uram vnius gradus impetus, & &longs;ic mediante &longs;enfu, & experientia non pote&longs;t eius &longs;ententia redargui.

PROP. LVI.

Reperire men&longs;uram certigradus impetus re&longs;pectu cuius di­&longs;cerni valeat an impetus de&longs;cen&longs;us terræ per ignem, vel a&longs;cen&longs;us ignis per mercurium &longs;it octo, vel quatuor graduum.

SEd prædictùm effugium &longs;ic refellemus: Fiat ex­perimentum non in mercurio &longs;implicitèr graui,

&longs;ed in aqua, vel in aere, illa enim habebittres gradus grauitatis, & vnicum lcuitatis, ergo ignis per aquam a&longs;cendet velocitate trium graduum; in mercurio ve­rò impetu octo graduum, & terra per ignem octies velociùs de&longs;cendet, quàm per aquam. Præterea aer habet vnicum gradum grauitatis, & tres gradus le­uitatis, igitur ignis octies velociùs per mercurium a&longs;cendet, quàm per aerem, vnde hac ratione habe­bimus men&longs;uram vnius gradus impetus tàm in a&longs;cen­&longs;u, quàm in de&longs;cen&longs;u, qui comparari pote&longs;t cum im­petu ignis per mercurium a&longs;cendentis, & terræ per ignem de&longs;cendentis; & proindè facilè conijci po­terit, an prædictæ velocitates extremorum elemen­torum reuerà &longs;int octuplæ, vel non, comparatæ ad velocitates quas exercent in intermedijs elementis.& licèt experimentum non det exactam præcifionem, nihilominùs &longs;ufficienti&longs;&longs;imè euincit fal&longs;itatem peri­pateticæ hypothe&longs;is, &longs;edlicèt reuerà vis, & energia, qua corpora a&longs;cendunt, vel de&longs;cendunt, minimè de­dci po&longs;&longs;it ex velocitate tran&longs;itus &longs;ursùm, vel deor­sùm, vt &longs;uo loco apertè o&longs;tendemus, tamen a&longs;&longs;umi pote&longs;t cum aduer&longs;ario ad eum redarguendum.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Con&longs;iderentur deindè elementa intermedia, vt &longs;unt aer, & aqua, &longs;eù alia corpora mixta, quæ ei&longs;dem gradibus leuitatis, & grauitatis afficiantur. Demon­&longs;trandum e&longs;t, nullum eorum corporum, quæ a&longs;cendunt &longs;ursùm po&longs;itiuam leuitatem habere.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LVII.

Si Aer in aqua &longs;olummodò leuitatem exerceret, in ea non a&longs;cenderet à leuitate eius po&longs;itiua impul&longs;us.

ET primò &longs;upponamus prædicta elementa no&ntail; retincre &longs;imùl eodemque tempore duas oppo­&longs;itas facultates grauitatis, & leuitatis, &longs;ed &longs;ucce&longs;&longs;i­uè modò vnam, modò alteram po&longs;&longs;ideant, prout in diuer&longs;is medijs fluidis collocantur, &longs;cilic èt aqua i&ntail; aere pendula &longs;olummodò grauis cen&longs;eri debeat, non autem leuis, &longs;i po&longs;tmodum aqua infrà hydrargyrum mergatur, tunc aqua leuis &longs;it, non autem grauis, po­

natur etiam, quod aer, &longs;eù lignum &longs;ub aqua demer&longs;um leue &longs;it, nec grauitatem vllam habeat. Con­cipiatur po&longs;tea vas RGHS a­qua D plenum, & in eo merga­tur ma&longs;&longs;a aeris, velligni F, pa­tet ergò ex &longs;upradicta hypo­the&longs;i, quod aqua D nullam leuitatem, &longs;ed tantummo­dò grauitatem habebit, eò quòd prædicta aqua non &longs;upponitur demer&longs;a intra aliud corpus fluidum den­&longs;ius, & pondero&longs;ius ip&longs;a, &longs;ed contigua e&longs;t aeri. Mo­dò quiaaer, vel lignum F &longs;upponitur ab aduer&longs;arijs &longs;ursùm a&longs;cendere à G, versùs R impul&longs;a à po&longs;itiua leuitate eius naturali, aqua verò circumfu&longs;a D cona­tum, atque impetum exercet deorsùm ab A versùs H veluti natura eius grauitatis exigit, habebimus ergò duos impetus ad inuicem contrarios, nempè leuitatis aeris F grad. 3. & grauitatis gra. 3. aquæ circumfu&longs;æ D, & hæ duæ virtutes motiuæ &longs;imùl &longs;um­ptæ gr.6. component men&longs;uram conatus, & impetus, quo lignum F per aquam a&longs;cendit, hoc tamen e&longs;t fal­&longs;um, & contra conce&longs;&longs;ionem eiu&longs;dem aduer&longs;arij, & contra demon&longs;trationem Archimedis, & tande&mtail; contra experientiam, quia ea, quæ feruntur &longs;ursùm in aqua, tanta vi a&longs;cendunt, quanta e&longs;t grauitas, qua moles aquæ æqualis corpori demer&longs;o &longs;uperat huiusmet grauitatem, quod perindè e&longs;t, ac &longs;i dica­tur impetum &longs;ursùm men&longs;urari à differentia grauita­tum aeris, & aquæ gr. 2. non autem ab aggregato gr. 6. leuitatis illius, & grauitatis huius. Quaprop­ter non poterit aer, vel lignum &longs;ursùm impelli ab eius leuitate po&longs;itiua.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Prop. 53.

PROP. LVIII.

Idip&longs;um ostendere po&longs;ito quòd aer, & aqua vtramque vim leuitatis, & grauitatis exerceat.

SVpponamus &longs;ecundo loco tam aerem, quàm aquam &longs;emper retinere ambas oppo&longs;itas qualitates, &longs;cilicèt perpetuò afficiantur ij&longs;dem gradibus graui­tatis, atque leuitatis &longs;itque leuitas aeris F trium gra­duum, & maior leuitate ip&longs;ius aquæ D vnius gradus; at è contrà gradus grauitatis eiu&longs;dem aeris F gra­dus vnius minor &longs;it pondere graduum 3. molis aquæ D, quæ æqualis &longs;it ip&longs;i F, habebimus profectò qua-tuor vires motiuas, quæ &longs;ibi mutuò aduer&longs;antur, & in libra imaginaria BI operantur, vt nimirùm nulla earum otiari queat, &longs;ed omnes &longs;imùl agant, & im­pellant, igitur ex propo&longs;itionibus 50. & 54. conatus, &longs;eù impetus quo aer F impellitur &longs;ursùm in aqua à G versùs R ratione leuitatis men&longs;urari debet ab ex­ce&longs;&longs;u 2. graduum quo leuitas eiu&longs;dem aeris &longs;uperat leuitatem aquæ circumfu&longs;æ, & è contra conatus aquæ contra aerem efficitur ab exce&longs;&longs;u grauitatis aquæ D, &longs;upra grauitatem aeris F paritèr gr. 2. & proindè dum aqua deorsùm de&longs;cendere conatur nece&longs;&longs;ariò aerem F exprimit, ac &longs;ursumm impellit; &longs;untque hæ duæ dif­ferentiæ, &longs;eù exce&longs;&longs;us virium contrariæ inter &longs;e, &longs;ci­licèt vna in libra imaginaria &longs;ursùm impellit, altera verò deorsùm igitur vniuer&longs;alis conatus, & impetus totalis quo aer F a&longs;cendit in aqua, men&longs;urari debet ab aggregato eorumdem duorum exce&longs;&longs;uum, quod e&longs;t gr. 4. non verò à differentia leuitatum, &longs;olummo­dò gr. 2. Sed hoc e&longs;t fal&longs;um contra experientiam, con­tra aduer&longs;arij a&longs;&longs;ertum, & contra ea, quæ ab Archi­mede demon&longs;trata &longs;unt, quia nimirùm conatus, & impetus quo fertur aerea pila &longs;ursùm in aqua æqua­lis e&longs;t differentiæ ponderum aeris, & aqu&ecedil;, igitur verum non e&longs;t leuitatem po&longs;itiuam in hac operati­one concurrere.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Prop. 54.

V&longs;que adhùc non con&longs;iderauimus difficultatem, aut impedimentum, quod affert medium fluidu&mtail; motui a&longs;cen&longs;us, vel de&longs;cen&longs;us corporum, quæ in ip­&longs;o feruntur, erit igitur operæpretium perpender&etail; quidnam admi&longs;&longs;o, vel negato prædicto peripatetico a&longs;mpto &longs;ub&longs;equatur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LIX.

Aliter id ip&longs;um ostendere, po&longs;ito, quòd aer vi leuitatis per diuer&longs;a media fluida a&longs;cendat.

SIt igitur idem mobile B, quod &longs;it lignum leui&longs;&longs;i­mum, vel ve&longs;ica aere plena, impellaturque v&longs;que ad fundum va&longs;is DCFE cuius medietas infima reple­atur aqua A, reliqua medietas &longs;uprema O repleatur oleo, vel &longs;piritu vini, & ponamus leuitatem aereæ ve&longs;icæ B e&longs;&longs;e trium graduum, & leuitatem &longs;piritus vini duorum graduum, at leuitatem aquæ magis den­&longs;æ e&longs;&longs;e vnius gradus. Manife&longs;tum e&longs;t, quòd re&longs;i&longs;ten­tia aquæ A, & partium tenacitas, quæ penetrari de­bet à ligno, vel ve&longs;ica B dùm &longs;ursùm a&longs;cendit, erit tan­ maior re&longs;i&longs;tentia &longs;piritus vi­

ni O quantùm illa e&longs;t magis den­&longs;a, & con&longs;tipata quàm i&longs;te, &longs;ci­licèt &longs;i &longs;umantur moles æquales eorumdem fluidorum, quantò maior e&longs;t corpulentia, & mate­ria, quæ pr&ecedil;dictum aqueum &longs;pa­tium replet ea materia quæ molem &longs;piritus vini oc­cupat, & quia leuitatem &longs;piritus vini ad leuitatem aquæ eamdem proportionem habere aiunt, quam illius raritas ad huius raritatem, igitur tantò magis di&longs;tra­hibilis, & minùs re&longs;i&longs;tens erit &longs;piritus vini, quà&mtail; aqua communis; quantò ille leuior e&longs;t aqua commu­ni, ergò re&longs;i&longs;tentia quam aqua in fert ve&longs;icæ a&longs;cenden­ti ad re&longs;i&longs;tentiam &longs;piritus vini eamdem proportionem reciprocè habet, quam &longs;piritus vini leuitas ad aquæ communis leuitatem. Quapropter aqua communis duplò re&longs;i&longs;tentior erit quàm &longs;piritus vini, veluti i&longs;te &longs;upponitur duplò leuior illo. Modò, quia aduer&longs;arius &longs;upponit, quòd conatus, & impetus quo a&longs;cendit aerea ve&longs;ica per prædicta duo fluida men&longs;urari de­beat ab exce&longs;&longs;u, &longs;eu differentia leuitatum eorumdem corporum, igitur aerea ve&longs;ica B, quætres gradùs le­uitatis habebat, a&longs;cendet per aquam A vnum gradum leuitatis habentem conatu, &longs;eu impetu men&longs;urato à differentia prædictarum leuitatum, quæ erit duorum graduum, &longs;ed in &longs;piritu vini O qui duos gradus leui­tatis habebat, a&longs;cendet, eadem pila B impetu æquali differentiæ leuitatum eorundem corporum, quæ erit vnius &longs;olummodò gradus, & hæc quidem con&longs;e quun­tur ex demon&longs;tratis in pr. 48. & 52. qua proptèr ra­tione differentiarum inter leuitatem corporis B, & leuitates prædictorum fluidorum ve&longs;ica B per aquam a&longs;cende natu, & impetu duplo eius, quo per &longs;pi­ritum vini eleuatur; nihilominùs velocitas qua præ­dicta ve&longs;ica B a&longs;cendit in aqua, non poterit e&longs;&longs;e du­pla eius, qua &longs;ublimatur in &longs;piritu vini, licèt virtus, & energia, qua impellitur per aquam dupla &longs;it eius, quæ in &longs;piritu vini exercetur, proptereà quod &longs;uper­uenit noua cau&longs;a, à qua prædicti impetus retardantur, & valdè alterantur, hæc verò e&longs;t maior den&longs;itas aquæ communis &longs;upra tenacitatem, & con&longs;tipationem &longs;pi­ritus vini; quæ, iuxtà Ari&longs;totelis a&longs;&longs;umptum, maiorem tarditatem a&longs;cendenti corpori affert den&longs;itas aquæ, &longs;cilicèt duplò maior, quàm &longs;it ea difficultas, qua à &longs;piritu vini a&longs;cen&longs;us eiu&longs;dem pilæ impeditur. Hinc &longs;equitur, quòd velocitas eiu&longs;dem pilæ B per aquam ad eam quam habere pote&longs;t per &longs;piritum vini com­po&longs;ita &longs;it ex duabus proportionibus, &longs;cilicèt ex pro­portione differentiarum leuitatum eorumdem cor­porum, quæ erit vt duo ad vnum, & ex propo&longs;itio­ne reciproca re&longs;i&longs;tentiarum eorumdem medioru&mtail;, quæ &longs;e habet vt vnum ad duo, &longs;ed proportio dupla, & &longs;ubdupla componunt proportionem æqualitatis, igitur æquali velocitate a&longs;cendet eadem ve&longs;ica B per aquam A, & per &longs;piritum vini O, quod e&longs;t euiden­tèr falfum, & contra a&longs;&longs;ertum eorumdem aduer&longs;a­riorum, ergo ve&longs;ica aere piena non mouetur &longs;ursùm in fluido vi leuitatis po&longs;itiuæ, quod erat o&longs;tenden­dum.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sed antequam vlterius procedamus, debent ad exa­men quoque reuocari aliæ obiectiones, quæ ab au­thoribus clari&longs;&longs;imis afferuntur contra no&longs;tram &longs;en­tentiam. Et primò quidem con&longs;iderabo argumenta, quæ de&longs;umuntur à pyramidali figura flammæ lucer­næ, a qua, inquam, figura putant euidens argumentum deduci, quòd flamma ip&longs;a &longs;ursùm impellatur ab in­terno principio leuitatis, &longs;icque ratiocinantur: Vi­demus quieto, & tranquillo aere flammum ferri &longs;ursùm pyramidalitèr, cùm tamen &longs;i per expres&longs;ionem hic motus fie-ret, inuer&longs;a flammæ figuræ e&longs;&longs;et, aut certè inferior pars non minùs quàm &longs;uperio acuminata, vt fit in omnibus non du­ris quando per expres&longs;ionem &longs;ursùm iaciuntur. Secundò quin­ta e&longs;&longs;entia vini in lapide accen&longs;a &longs;ursùm fertur non per ex­pres&longs;ionem, &longs;ed in&longs;ita leuitate, aer enim exprimens, vel e&longs;&longs;et &longs;ub ba&longs;i ignis auolantis, & illum protruderet, quod e&longs;t fal&longs;um; vel &longs;uperincumbens grauitando hanc expres&longs;ionem efficeret; neque hoc, quia &longs;ic aer vertici ignis incumbens eum deprimeret potiùs, ac reuerberaret deorsùm, quàm &longs;ursùm.

Noua argu­menta pro leuitate po­&longs;itiua afferun­tur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LX.

Flammam in camino ab expres&longs;ione ambientis aeris &longs;ursùm impelli.

PRimæ difficultati, quòd nimirum flamma lucer­næ in aere quieto, & tranquillo moueatur &longs;ur­sùm &longs;ponte, non verò per extru&longs;ionem factam ab ae­re ambiente, &longs;atisfacere nitemur adducendo experi­menta aliqua. Videmus enim maiores, & ampliores flammas in caminis accen&longs;as non vigere, nec diutiùs per&longs;euerare ni&longs;i ad&longs;it aditus aeri de foris aduenienti, per quem ingrediatur ventus perpetuus, qui inter crura, & fœmora ignem circum&longs;tantium excurrit ver­sùs flammam, e&longs;tque euidentèr &longs;en&longs;ibilis, nam &longs;i cu­biculi o&longs;tium claudatur exten&longs;o panno, vel cortina, vt fieri &longs;olet, h&ecedil;c inflatur ver&longs;us ignem camini, vt ve­lum nauis; imò in cubiculis vndiquè diligentèr clau­&longs;is, in quibus aer externus &longs;ubingredi nequeat non poterit flamma &longs;ursùm impelli ab aere, quin cubi-culum inane remaneat, & tunc ignis camini nullo pa­cto accendi pote&longs;t, nec in flammam verti, aut per­durare, ni&longs;i o&longs;tiolum, vel foramen aliquod in ip&longs;o ca­mino aperiatur, & tunc facilè flamma accenditur, & per&longs;euerat. Ratio huius effectus pendet nedùm ab impul&longs;u flammæ &longs;ursùm, &longs;ed etiam à rarefactione ae­ris propè ignem exi&longs;tentis, eumque ambientis per to­tam camini longitudinem, quia nempe aer prædictus ab igne calefactus minùs grauis &longs;pecie redditur, quam aer cubiculi, & externus, qui à camino di&longs;tat; Hoc autem nece&longs;&longs;ariò aduenit ex legibus mechanicis, & ex Archimedis demon&longs;trationibus; nece&longs;sè enim e&longs;t, vt aerrarior, & minùs grauitans &longs;ursùm expellatur exprimaturque à grauiore aere circumambiente, hinc fit vt po&longs;t a&longs;cen&longs;um illius aeris rarefacti per caminum diminuatur moles aeris ip&longs;ius cubiculi propè, & cir­ca caminum. Non ergo mirum e&longs;t, nouum aerem pro­fluere ad replendum cubiculi &longs;patium, & hæc e&longs;t cau­&longs;a, quare percipitur ventus ille, & effluuium per­petuum dum flamma camini viget.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Prædictum ratiocinium confirmari pote&longs;t à pul­cherrimo experimento à D. Candido Buono Floren­tiæ mihi communicato.

PROP. LXI.

Trutinæ æquilibratæ vna lanx excalefacta &longs;ursum eleuatur extru&longs;a à pondere aeris, reliquam lancem ambientis.

ERat enim trutina, &longs;eù bilanx tantæ perfectionis, vt à quinquage&longs;ima parte vnius grani hordei, imò à multo leuiori fe&longs;tuca flecti facilè po&longs;&longs;et. hæc quidem &longs;u&longs;pen&longs;a intra arm ariolum vitreum, vt à &longs;or­dibus, & venti agitatione tueretur æquilibrium præ­cisè &longs;eruabat, vt e&longs;t DE, cuius centrum C, tunc sump­ta virga ferrea IF, & igni­

ta in eius extrema parte F lanci A approximaba­tur, ab&longs;que contactu, tunc libra ab æquilibrio remo­uebatur, depre&longs;&longs;a nimi­rum lance B, & eleuata A, idenque contingebat trans­lato ignito ferro infra lancem, ac priùs in&longs;uprema lancis parte ob&longs;eruabatur: rationem huius admirabilis effect9hanc excogitaui, & amico petenti reddidi eamque con­municaui Societati docti&longs;&longs;imorum virorum à Sereni&longs;s. & Eminenti&longs;s. Cardinali Leopoldo Mediceo erectam, quam deinceps more Italico Academiam experimen­talem Mediceam vocabo. Concipiantur duæ &longs;phæ­rulæ aeris inter &longs;e æquales LG, & HK lances ambien­tes, quæ erunt æquè graues, &longs;cilicèt eiu&longs;dem &longs;peciei. Approximato po&longs;tea ferro ignito IF procùldubio à profluuio ignearum exhalationum à feruente ferro emanantium, calefit nedum lanx illa metallica A, &longs;ed etiam &longs;phæra proximi aeris LG, quæ proindè ingen­tem raritatem acquirit, cùmque aer ambiens LG ar­ctè adhæreat lanci A, eiu&longs;que a&longs;peritatibus, & foueolis, colligatus componat veluti lanuginem vnitam ip&longs;i lanci, itaut nequeat moueri lanx A ni&longs;i &longs;ecum deferat aeream lanuginem, &longs;eu cru&longs;tam contig uam, & con­nexam LG, verùm lanci oppo&longs;itæ B, adhæret &longs;phæ­ra aerea HK den&longs;ior, vt potè non excalefacta à ferro feruente; hinc fit vt &longs;umma lancis B vnà cum adnexa cru&longs;ta ambientis aeris HK grauior &longs;it ærea lamina A vnà cum rariori lanugine aeris adhærentis LG. Mirum igitur non e&longs;t, quòd a maiori pondere libræ extremi­tas E deprimatur, & ei oppo&longs;ita D eleuetur. Eodem ferè modo, vt dicebam priùs, aer cubiculi circ&atail;, caminum cùm &longs;it valdè den&longs;us, comparatus cum flan­ma, & aere calefacto intra caminum exi&longs;tente, & ideò valdè rarefacto, mirum non e&longs;t &longs;i proptèr illius grauitatem excedentem &longs;ursùm exprimat leuiorem flammam, acremque adhærentem paritèr rarum. E&longs;t igitur euidenti&longs;&longs;imum in hi&longs;ce experimentis, quòd aer flammam ambiens, nedùm eam exprimit, &longs;ed bonam partem aeris rarefactam vnà cum flamma impellit quo­que &longs;ursùm. Sed dicet aliquis, cur circa flamma&mtail; lucernæ non ob&longs;eruatur prædictus ventus? re&longs;pon­detur non e&longs;&longs;e æquè &longs;en&longs;ibilem, quia nimirum lucer­næ flamma non in&longs;inuatur intra fi&longs;tulam aliquam, vt e&longs;t canalis camini, qui exitum habet extra cubiculum; cùm ergo lucernæ flamma vndique ambiatur abaere aperto ab&longs;que euidenti con motione eam impellere &longs;ursùm pote&longs;t exprimendo, nimirùm facto breui cir­cuitu à vertice flammæ v&longs;que ad eius ba&longs;im, & ob flamm&ecedil; exiguitatem parua quoque e&longs;t moles aerisei contigua, qu&ecedil; agitatur, & conuoluitur, & hæc e&longs;t ratio, quare circa lucernæ flammam ventus non ob-&longs;eruatur &longs;imilis ei, qui propè caminum percipitur.

Cap 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Hæc experi entia, & ra­tio eius ap­plicatur flan­ camini a&longs;cend ntis.

Ratio quare circa lucer­næ flammanon percipi­tur ventus &longs;icuti in ca­mino.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXII.

Ignem non à leuitate, &longs;ed ab extru&longs;ione ambientis aeris a&longs;cen­dere, euincitur ex de&longs;cen&longs;u fumi in vacuo Torricelliano.

SEd quòd reuerà ignis mo­

ueatur &longs;ursum per extru&longs;i­onem ambientis aeris, non autem a&longs;cendat &longs;ponte propria vir­tute euidenti&longs;&longs;imè percipitur ex hoc meo experimento, quod Florenti&ecedil; Sereni&longs;&longs;imo Leopol­do Cardinali Mediceo commu­nicaui, comprobatumque fu­it in Academia Experimentali Medicea, & demum Exteris per Epiftolas diuulgatum fuit.

Sit vas vitreum AFG, cuius longitudo EF duobus cubitis maior &longs;it, habeatque annexam ampullam vitream CEM, &longs;it­que incuruata eius extremitas HFG, atque duæ eius extremitates A, & G &longs;int perforatæ, & apertæ, & pri­ùs &longs;trictè ob&longs;erato, duplici ve&longs;ica &longs;uilla, infimo orificio G repleatur vas vniuer&longs;um hydrargyro infu&longs;o per &longs;u­premum os AB, po&longs;tea pilula aliqua D ex bitumine aliquo atri coloris operculo ex bractea ferrea filo alligetur; & Orificium AB denuò ve&longs;icategatur, colligeturque &longs;trictè: tandèm &longs;ublata ve&longs;ica infima G concedatur egre&longs;&longs;us hydrargyro, vt nimirùm facta &longs;olita vacuitate aeris remaneat hydrargyrum &longs;u&longs;pen­&longs;um v&longs;que ad O, & altitudo GO erit proximè vnius cubiti, & quadrantis. His præparatis &longs;umatur lens aliqua cry&longs;tallina KL, & directè Soli S exponatur in ea di&longs;tantia, & &longs;itu in quo præcisè vertex coni radio­&longs;i à radijs Solis refractis conuergentibus formati ad contactum pilæ bitumino&longs;æ D pertingat. Idip&longs;u&mtail; fieri pote&longs;t ope &longs;peculi concaui v&longs;torij radios Solis reflectentis, tunc lique&longs;cere incipit pila D, & fumum emittit, in quo apparet mirabilis operatio, non enim fumus, veluti in aere aperto accidit, &longs;ursùm a&longs;cen­dit, &longs;ed incuruatur flectiturque deorsùm per DMN non &longs;ecùs ac virgulæ illæ aquæ cadentis è fontibus, inflexas, & deorsùm tendentes lineas de&longs;cribunt.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Porrò quia fumum non minùs quàm flammam leuem e&longs;&longs;e, atque &longs;ursùm moueri &longs;ponte &longs;ua à naturali prin­cipio impul&longs;a, communiter Peripatetica Schola docet, igitur nece&longs;&longs;ario in &longs;patio illo vacuo CEN, vel &longs;al­tèm in quo aer non degit ni&longs;i valdè expan&longs;us, & rare­factus, fumus maiori vi &longs;ursùm a&longs;cendere deberet, quàm in aere aperto, quia nimirùm ab aeris cor­pulentia aliquo pacto impeditur ip&longs;ius progre&longs;­&longs;us (videmus enim in aere aperto fumum ampliari, di&longs;&longs;ipari, ac di&longs;pergi à prædicta aeris re&longs;i&longs;tentia,) cun­que in &longs;patio illo vacuo, vel à quo aer de&longs;icit po&longs;&longs;it fumus naturali leuitate non impeditus liberiùs, & fa-ciliùs eleuari, igitur omninò nece&longs;sè e&longs;&longs;et vt fumus in prædicto vacuo &longs;patio a&longs;cenderet &longs;ursùm, veluti eius natura exigit, & è contrà e&longs;&longs;et impo&longs;&longs;ibile vt deorsùm deprimeretur, & caderet, vt virgulæ deci­dentes aquæ fontium flectuntur deorsùm; quia verò hoc experientiæ repugnat non poterit dici, quòd fu­mus &longs;it leuis, &longs;ed è contrà grauis erit. Cùm verò i&ntail; aere idem fumus &longs;ursùm a&longs;cendat, dicendum e&longs;t quòd ab aere ambiente grauiori in &longs;pecie, quàm &longs;it fumus iuxtà leges mechanicas libræ aer premens per extru­&longs;ionem &longs;ursùm fumum minùs grauem expellit.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXIII.

Figuram pyramidalem flammæ lucernæ non &longs;uadere eam à vi leuitatis &longs;ursùm impelli.

VErùm, quod ad formam pyramidalem flammæ lucernæ pertinet, non videtur, quòd eius figu­ra conica nece&longs;&longs;ariò per&longs;uadeat, & conuincat flam­mam &longs;ursùm &longs;ponte &longs;ua, & propria virtute leuitatis a&longs;cendere, nam &longs;iue per extru&longs;ionem ambientis &longs;lui­di violenter, &longs;iuè &longs;ponte à vi leuitatis &longs;ursùm moue­ri &longs;upponamus, retinere æquè benè po&longs;&longs;et eamde&mtail; conicam figuram, vt inferiùs o&longs;tendemus. Præterea &longs;i vera cau&longs;a figuræ pyramidalis flammæ lucernæ e&longs;&longs;et eius leuitas po&longs;itiua, debereteadem leuitas po&longs;itiua eumdem effectum producere in reliquis omnibus corporibus fluidis paritèr ab ip&longs;a impul&longs;is, &longs;i tamen reliqua &longs;int paria, &longs;cilicèt fumus non &longs;ecùs ac flam-ma corpus fluidum, & rarum e&longs;t, cuius continentèr vna pars po&longs;t aliam generatur, & eructatur à po­ris eiu&longs;dem titionis, pariterque fumum leuitate&mtail; po&longs;itiuam habere, & exercere &longs;upponunt non minùs, quàm flamma habet, igitur nece&longs;&longs;ariò fumus a&longs;cen­dens, & digrediens à titione deberet formam pyra­midalem acquirere &longs;imilem ei, quam flamma lucer­næ habet, deberetque paritèr in acumen &longs;ubtile &longs;u­periùs definere, quod profectò e&longs;t fal&longs;um, & contra &longs;en&longs;us euidentiam, pro&longs;equitur enim fumus &longs;uu&mtail; iter longo tractu &longs;ursùm ab&longs;que eo quòd in acumen reducatur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Id ip&longs;um continget, &longs;i fi&longs;tula aliqua aer in fundo aquæ in&longs;uflletur, con&longs;picientur enim eleuari innume­ræ ampullæ aere&ecedil;, quæ ab inuicem &longs;eparantur ab&longs;­que eo quòd pyramidalem figuram acquirant, licèt aer non minùs quàm flamma leuis reputetur, & ab in­trin&longs;eco principio &longs;ursùm moueri credatur, cùmque vna, & eadem cau&longs;a non po&longs;&longs;it diuer&longs;os effectus pro­ducere, concedant nece&longs;sè e&longs;t, figuram, quam in flan­ma ob&longs;eruamus diuer&longs;am à figura fumi, & aeris per aquam a&longs;cendentis ab alia caufa longè diuer&longs;a de­pendere, non autem à prædicto principio intrin&longs;eco leuitatis.

Et profectò &longs;i attentè perpendamus fumi, & flam­mæ con&longs;i&longs;tentias, valdè inter &longs;e differre reperiemus, licèt ambo &longs;int corpora rara, & fluida.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXIV.

Fumi structura, & compo&longs;itio declaratur.

COn&longs;tat fumum e&longs;&longs;e ma&longs;&longs;am copio&longs;am particula­rum exiguarum olei, terræ, & aquæ, quæ par­ticulæ ab inuicem di&longs;cretæ, & &longs;eparatæ nondù&mtail; accen&longs;æ &longs;unt, licèt valdè excalefactæ &longs;int. hoc planè confirmatur ab operatione chymica, po&longs;&longs;unt eni&mtail; recolligi ex fumo partes aqueæ &longs;egregatæ, & di&longs;cre­tæ à partibus vnctuo&longs;is, & &longs;ulphureis, nec non à particulis terreis, & fuligino&longs;is, & vici&longs;&longs;im quæli­bet ex prædictis &longs;ub&longs;tantijs recuperari pote&longs;t &longs;epa­rata à reliquis; præterea con&longs;tat &longs;en&longs;u, fumum no&ntail; e&longs;&longs;e corpus continuum, &longs;ed aggregatum ex particu­lis minimis ab inuicem &longs;eparatis, & di&longs;cretis, vt præ­clarè in nebula ob&longs;eruatur, & in alijs aqueis vapo­ribus, qui&longs;i attentè con&longs;piciantur in loco commodo, ide&longs;t &longs;i interpo&longs;ita nebula vi&longs;us dirigatur in&longs;piciat­que ob&longs;curum, & tenebro&longs;um aliquem locum, & in­terim Sol transuer&longs;alitèr eamdem nebulam illu&longs;tret; tunc illa nebula, quæ repre&longs;entabatur continua ap­paret e&longs;&longs;e con&longs;lata ex immen&longs;a multitudine exiguo­rum granulorum aquæ, quæ lento quodam motu per aerem agitantur, vt contingit in ijs fragmentis ter­reis minuti&longs;&longs;imis, quæ con&longs;piciuntur in radijs Solis intra cubicula. Iam prædicta granula aquea copio­&longs;i&longs;&longs;ima vagantia per aerem non facile vi&longs;ibilia &longs;unt &longs;igillatim ob eorum exiguitatem, &longs;ed po&longs;&longs;unt tran-&longs;itum luci impedire, & componunt apparentiam il­lam vnius &longs;ub&longs;tantiæ raræ, & expan&longs;æ, vti pariter multoties accidit in tempore pluuiæ, quo guttæ aquæ decidentes ab inuicem &longs;eparat&ecedil;, &longs;i à loco aliquo di&longs;tanti, & remoto in&longs;piciantur, &longs;imillimæ videntur nebulis, & fumo.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXV.

Fumus non e&longs;t res accen&longs;a, & quamobrem ab ambiente ac­re &longs;ursùm exprimi pote&longs;t.

QVòd po&longs;tea partes minimæ fumum componen­tes non &longs;int adhùc accen&longs;æ, experientia con&longs;tat, quia videmus multoties fumum accendi, atque in­flammari quando eum tangit flamma viua alicuius can­delæ, prætereà videtur quoque impo&longs;&longs;ibile fumum e&longs;&longs;e rem accen&longs;am, quia nimirùm fumus gignitur in cauitatibus, atque poro&longs;itatibus internis &longs;igni, vel cuiuslibet alterius corporis fumum eructantis, &longs;ed in hi&longs;ce locis angu&longs;tis re&longs;tricti&longs;que nedum fumus ac­cendi non pote&longs;t, vt è contrà flammæ ip&longs;æ iam accen­&longs;æ in ei&longs;dem locis angu&longs;tis conclu&longs;i&longs;que momento extinguantur, &longs;uffocenturque; imò licet concauita­tes cauerno&longs;æ &longs;int ampl&ecedil;, vt e&longs;t cauitas alicuius later­næ vndique occlu&longs;æ, &longs;ubitò flamma extinguitur, quan­ magis hoc fieri debet quando cauitates, & poro­&longs;itates &longs;unt re&longs;trictæ, & angu&longs;ti&longs;&longs;imæ, vt &longs;unt pori li­gni, vel alterius con&longs;imilis corporis. Licèt ergo præ­dicta fragmenta exigua fumum componentia non &longs;int actu accen&longs;a, vel inflammata nihilominùs valdè exca­lefacta, & rara e&longs;&longs;e &longs;olent, & hæc quidem raritas, & agitatio earundem fumi particularum, producta ab exha­lationibus igneis, à quibus priùs euul&longs;æ, & &longs;egre­gatæ fuerunt à ma&longs;&longs;a lignea, vel alterius corporis, e&longs;t in cau&longs;a vt non po&longs;&longs;int am pliùs in angu&longs;tis illis poro­&longs;itatibus retineri, & proindè coguntur ingenti impe­tu eructari, effluere que per orificia patentia earum­dem poro&longs;itatum, quæ orificia cùm vndique pateant, fit vt fumus exeat nedùm è parte &longs;uprema ligni, &longs;ed etiam à parte infima, & laterali. Diffractis itaque re­pagulis carcerum, egre&longs;&longs;i&longs;que fumi partibus in aere aperto non &longs;ine &longs;ocietate ignearum exhalationu&mtail; ma&longs;&longs;am componunt minùs grauem ip&longs;o aere ambien­te, & ideò poterunt ab eodem exprimi, & lento mo­tu impelli &longs;ursùm atque tàm diù a&longs;cen&longs;us per&longs;euera­bit, quou&longs;que exhalationes igneæ ab ip&longs;is particulis fumi non di&longs;cedant exhalentque, & pariter v&longs;quequò deficiat impetus præconceptus ab ip&longs;o impul&longs;u præ­cedenti, à quo lento quidem motu per aerem fluctuan­do aliquanti&longs;per fumi commoueri poterunt, cù&mtail; præterea exiguitas particularum eiu&longs;dem fumi cau­&longs;a &longs;ufficiens &longs;it, vt diù à qualibet minima aeris agita­tione &longs;u&longs;pen&longs;æ retineri po&longs;&longs;int, vt videmus puluerem terre&longs;trem graui&longs;&longs;imum per aerem di&longs;pergi, ibiqu&etail; diù retineri, vt experientia docet.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXVI.

Fumi non ab impetu quo eructantur ad altis&longs;imas regiones perduci po&longs;&longs;unt, &longs;ed minùs graues redditi ab igniculo­rum commixtione exprimi ab ambiente aere po&longs;&longs;unt.

ET notandum e&longs;t, quòd ab&longs;que exhalationibus igneis non po&longs;&longs;ent ad in&longs;ignem altitudine&mtail; fumi particulæ eleuari, quia licèt impetus ex &longs;ui na­tura, quo à ligni poro&longs;itatibus eructantur, vim per &longs;e haberet ad eas longiùs eleuandas, nihilominùs, quia huiu&longs;modi impetus facillimè debilitatur extingui­turque à particulis aeris quie&longs;centibus, vel prædicto motu priuatis, quibus occurrunt fumi, non po&longs;&longs;et eius a&longs;cen&longs;us longiùs propagari, &longs;ed citò extingueretur. Vlteriùs &longs;i re vera fumi à ligno eructati virtute im­petus præconcepti ad tantam altitudinem a&longs;cenderent, non au­tem ob &longs;ocietatem ignearum exhalationum, &longs;equeretur, &qtail; non &longs;emper fumus ad eandem admo&longs;phær&ecedil; &longs;ummitatem a&longs;cenderet, is enim qui per poros laterales ligni e­greditur, impetum proiectitium tran&longs;uer&longs;alem acqui­reret, & ideò pro&longs;equi &longs;uum motum deberet per pla­num horizontalem, neque ab incepto itinere tanto­pere deuiaret: &longs;imiliter fumus ille, qui ab infima par­te titionis in aere &longs;u&longs;pen&longs;i exit, impetum acquirit ten­dendi deorsùm, non &longs;ursùm, proindeque deberet di­rectè profluere v&longs;que ad pauimentum, & deinceps non po&longs;&longs;et ad &longs;u premam aeris regionem perduci, quæ omnia fal&longs;a &longs;unt, & contra &longs;en&longs;us euidentiam; Fatendum igitur e&longs;t, ab igneis particulis fumum ra­refactum eleuari ab impul&longs;u grauioris aeris ambien­tis per expre&longs;&longs;ionem.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXVII.

Flamma e&longs;t fumus accen&longs;us magis rarefactus, qui ab aere ambiente velocis&longs;imè &longs;ursùm exprimitur.

PErcepta iam & declarata fumi con&longs;tructione per­pendere modò iuuat metamorpho&longs;im, qua&mtail; patitur quando inflammatur. Debemus igitur con­cipere minimas particulas &longs;ulphureas in fumo con­tentas, cùm inflammantur, maximè dilatari, rarefieri, & vehementi&longs;&longs;imè agitari, & in hoc con&longs;i&longs;tere eius accen&longs;ionem, &longs;ed granula illa aquea, & terrea eiu&longs;­dem fumi, quæ ex &longs;ua natura accen&longs;ibilia non &longs;unt, poterunt tantummodò rarefieri multò magis, quàm priùs. iam à prædicta ferè momentanea rarefactione, agitatione, & accen&longs;ione &longs;ub&longs;equitur con&longs;equen­tèr &longs;plendida, & lumino&longs;a apparentia flammæ. Ad hæc aeris ambientis grauitas, licèt exigua &longs;it, &longs;upe­rabit nihilominùs notabili exce&longs;&longs;u minimum, & in­&longs;en&longs;ibile pondus ip&longs;ius flammæ multò, & multò ma­gis, quàm &longs;uperauerat pondus præcedentis fumi:hinc nece&longs;&longs;ariò flamma ab ip&longs;o aere per extru&longs;ionem &longs;ur­sùm impelletur ineffabili velocitate. Et hìc plurima aduertenda &longs;unt.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXVIII.

Flamma rarior fumo minus &longs;patium occupat ob maximam eius velocitatem, redditurque po&longs;tea inui&longs;ibilis noua de cau&longs;a, & tactui languida ob eius di&longs;per&longs;ionem.

OB&longs;eruatur profectò titionem fumi copiam ingen­tem euomere, &longs;ed &longs;i denuò eius flamma reui­ui&longs;cat, h&ecedil;c mirabili velocitate fumi illius va&longs;tam mo­lem ab&longs;umere videtur, eumque in exiguum &longs;patium flammæ concludere, cùm reuera non &longs;it re&longs;trictio, flamma enim maiorem raritatem habet, quàm fumus, pendet ergo hoc ab ineffabili velocitate partiu&mtail; flammæ. aliundè enim notum e&longs;t per re&longs;trictum flu­minis canalem molem ampli&longs;&longs;imam aquæ totius flu­minis pertran&longs;ire, non quia in exiguo, & re&longs;tricto illo &longs;patio canalis conden&longs;etur tota aqua fluuij, d quia veloci&longs;&longs;imo motu per eum excurrit; cùm è contrà in parte ampla fluuij aqua lenti&longs;&longs;imo cur&longs;u progredia­tur, &longs;ic paritèr in fumo particulæ eius lento, & tardo gradu excurrentes amplum, & grande &longs;patium oc­cupabant, in flamma verò eædem particulæ veluti per &longs;tricti&longs;&longs;imum canalem mirabili, & ineffabili veloci­tate currunt, & &longs;ic po&longs;&longs;unt exiguum &longs;patium comple­re. Sed quare flamma vltra verticem eius non exten­ditur, neque vi&longs;ibilis redditur? hìc primò dicendum, quòd reuerà flamma producitur vltra eius verticem per notabile &longs;patium, & hoc quidem percipitur non vi&longs;u, &longs;ed tactu, po&longs;&longs;um enim ab&longs;que noxa manum ad latus flammæ approximare, vt ferè eam contingam, non verò po&longs;&longs;um manum &longs;upra flammæ verticem i&ntail; notabili di&longs;tantia vnius palmi ab&longs;que dolore, & v­&longs;tione retinere, igitur dicendum e&longs;t, quòd &longs;ub&longs;tan­tia illa ignita vltra verticem flammæ redditur tran&longs;­parens, & ideò inui&longs;ibilis alia noua de cau&longs;a efficitur. Sed tamen negari non pote&longs;t productio, & exten&longs;i&longs;ub &longs;tantiæ igneæ vltra flammam productæ, cùm hoc ab ip&longs;o tactu conuincatur. Sed dices, quare &longs;upra flan­ verticem in multò maiori altitudine non ampliùs tactu percipitur effluuium calidi&longs;&longs;imum eius, vt pro­pè eius verticem percipie batur? At for&longs;an hoc acci­dit, quia ignea &longs;ub&longs;tantia fluidi&longs;&longs;ima ab occur&longs;u aeris di&longs;pergitur, & &longs;ubdiuiditur in alias partes minores ab inuicem diui&longs;as, & di&longs;cretas, vt videmus aquæ copiam è &longs;umma turri delap&longs;am in progre&longs;&longs;u de&longs;cen­&longs;us &longs;ubdiuidi in innumeras guttulas inter &longs;e di&longs;cre­tas, & &longs;icuti non æquè humectat, & madefacit pluuia illa, ac ma&longs;&longs;a integra aquæ vnita, quia nimirùm nul­la pars &longs;ubiecti corporis à ma&longs;&longs;a continua aquæ tacta relinquitur arida, cùm in pluuia non omnes partes &longs;o­li madefiant humectentur que, ita propè verticem flan­ ignis vnitus manum percutit, atque terebrat, cum è contra in remotiori altitudine &longs;picula illa ignea val­dè di&longs;creta plagas exiguas, & inter &longs;e di&longs;tantes i&ntail; ip&longs;a manu inferant, & hinc minori noxa, minorique dolore incur&longs;us ignis tolerari poterit.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXIX.

Flammæcandelæ vertex acuminatur, quia magis accen­&longs;us, & ideò velociùs a&longs;cendit, quàm ba&longs;is eius.

PRæterea &longs;upponendum e&longs;t, flammam candelæ non habere con&longs;i&longs;tentiam homogeneam, & &longs;imila­rem, pars enim infima flammulæ non e&longs;t omninò ac­cen&longs;a, quod con&longs;tat ex eius colore &longs;ubliuido, qui&atail; nimirùm fumi oleo&longs;i eructati ab elicnio, velligno non in in&longs;tanti, &longs;ed in tempore accendi debent, igitur veri­&longs;imile e&longs;t, quòd non omnes pr&ecedil;dicti fumi &longs;ubitò po&longs;tgre&longs;&longs;um in ip&longs;o contactu ba&longs;is flammæ &longs;imùl, & inte­grè accendantur, & propterea rarefactio, & accen­&longs;io continuatur dùm actu excurrunt illæ particulæ à ba&longs;i versùs verticem flammæ. Modò &longs;i in ba&longs;i flam­mulæ fumi non &longs;unt omninò, & integrè accen&longs;i, non habebunt veloci&longs;&longs;imum illum motum, cuius capax e&longs;t flammæ puræ natura, igitur in ip&longs;a flamma conci­pi debet pars infima tardior, quàm &longs;uprema, & ver­ticalis, &longs;ed &longs;icuti in fluuio nulla alia de cau&longs;a tant&atail; copia aquæ in angu&longs;ti&longs;&longs;imum &longs;patium aluei re&longs;trin­gitur coangu&longs;taturque, ni&longs;i quia veloci&longs;&longs;imè excur­rit, cùm è contrà in locis dilatatis, & amplis eadem aquæ fiuminis moles amplius &longs;patium aluei ob eius tarditatem occupet, ita in flamma lucernæ, quæ vt fluuius ignis excurrentis concipi pote&longs;t, mirum non e&longs;t, quòd in ba&longs;i propè elicnium ob tarditatem eius fluxus ampliorem &longs;itum occupet, quàm in eius ver-tice, vbi velociori cur&longs;u fugit.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Hinc colligitur, quòd ex figura pyramidali, & a­cuminata flammæ lucernæ non euincitur eam à vi intrin&longs;eca leuitatis &longs;ursùm impelli. Cùm è contrà de­claratum &longs;it, qua ratione ab&longs;que po&longs;itiua leuitate ab expre&longs;&longs;ione aeris grauioris ambientis &longs;ursùm expel­latur, pariterque o&longs;ten&longs;a e&longs;t cau&longs;a prædictæ eius fi­guræ acuminatæ & in verticem de&longs;inentis, quæ non pendet à leuitate propria, &longs;ed ab expre&longs;&longs;ione aeris maxima velocitate facta in eius acumine magis accen­&longs;o, & hoc confirmatur ex eo quòd multotiès flammæ candelarum non &longs;unt pvramidales, &longs;ed rotundæ, aut oblongæ, & ouales, & hoc clarè con&longs;picitur quandò virga illa fumo&longs;a, quæ eructatur ab infima lucern&atail; nupèr extincta, denuò accenditur à contactu alte­rius flammæ in notabili di&longs;tantia ab inferiori cande­la, & tunc fumus inflammatus per longitudinem to­tius fumi &longs;ubiecti deorsùm labitur v&longs;que ad elicnium &longs;ubiectæ lucernæ, con&longs;piciturque euidentèr figura illius fumi accen&longs;i perfectè rotunda, imò cum primò lu­cerna accenditur, eius flamma rotunda e&longs;t, & po&longs;tea verticem conicum acquirit. in flammis verò camini non ob&longs;eruantur formæ pyramydales, &longs;ed multipli­citèr diui&longs;æ multotiès radios, &longs;eù linguas referunt, & aliquando rotundæ con&longs;piciuntur, & &longs;ic eleuan­tur per aliquod &longs;patium. Sed de his &longs;atis.

Concluditur quod ex &longs;i­gura acumi­nata flammæ lucernæ non euincitur hanc à vi le­uitatis afcen­dere.

Præterea all­quæ flammæ candelæ &longs;unt rotundæ, & flammæ ca­mini &longs;unt al terius figu­ræ.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXX.

Flammain &longs;piritu vini accenditur extra, & longè ab ip&longs;o­&longs;piritu, & ideò pote&longs;t exprimi &longs;ursùm ab ambiente aere.

VIdeamus modò an ex accen&longs;ione vini &longs;piritus deducatur a&longs;&longs;ertio leuitatis po&longs;itiuæ. Et hic denuò dico, quòd flamma &longs;piritus vini non e&longs;t actu accen&longs;a in poris internis prædicti liquoris, &longs;ed &longs;icuti de fumis lignorum dictum e&longs;t, educitur è &longs;piritus vi­ni fiuore fumo&longs;a quædam ma&longs;&longs;a rari&longs;&longs;ima, quæ in po­ro&longs;itatibus fluoris cùm retineri nequeat, ruptis car­cerum repagulis ingenti impetu per orificia poro&longs;a vndique fluorem ambientia eructat, & po&longs;tmodu&mtail; flammam concipit, accenditurque in aliqua &longs;en&longs;ibi­li di&longs;tantia à dicto fluore: hoc confirmatur exemplo illius effluuij fumo&longs;i, egredientis ab aliqua titionis poro&longs;itate, quod po&longs;tmodum accenditur in di&longs;tan­tia vnius digiti ab ip&longs;o ligno, & &longs;peciem præbet flu­oris bitumino &longs;i lateralitèr defluentis, qui in aer&etail; ignem concipiat. Cùm igitur ab omnibus poro&longs;ita­tibus &longs;piritus vini, & cuiuslibet materiei accen&longs;ibi­lis vndequaque &longs;ursùm, deorsùm, & lateralitèr fu­mo&longs;æ exhalationes egrediantur, quæ po&longs;tea in ip&longs;o aere aperto inflammentur, & accendantur, non vi­detur difficile vt aer po&longs;&longs;it infra flammam accen&longs;am, & lateralitèr eam comprimere, & proinde expre&longs;&longs;io­ne facta eam &longs;ursùm impellere: & notandum e&longs;t, quòd expre&longs;&longs;io, quæ ab aere efficitur, non &longs;emper a&longs;&longs;imila­tur ei, quæ ex compre&longs;&longs;ione po&longs;tica digitorum crea­tur, veluti prunorum nucleos à digitis po&longs;ticè com­pre&longs;&longs;is pueri proijcere longè &longs;olent, vtque aduer&longs;a­rius exi&longs;timabat, &longs;ed expul&longs;io, & expre&longs;&longs;io flammæ facta ab aere circumfu&longs;o fit, vt exigit ratio mechani­ca &longs;iphonis &longs;ursùm inuer&longs;i vt ex elementis hidro&longs;ta­ticis con&longs;tat, vtque meliùs inferiùs declarabitur vn­de malè infertur, quòd &longs;i flamma expul&longs;a e&longs;&longs;et ab am­biente aere, deberet fieri acuminata in eius ba&longs;i, & rotunda in eius vertice.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 2.

PROP. LXXI.

Flamma in &longs;piritu vini accen&longs;a non debet ab aere incum­bente contundi, cùm ab eius pondere non exprimatur &longs;ursùm, &longs;ed ab aere collater ali infernè reflexo.

PO&longs;trema in&longs;tantia, quòd aer flammæ &longs;uperincun­bens potiùs eam deberet contundere, & dila­tare, & deorsùm eam diuerberare, non autem in acu­tiem &longs;ublimare, facilè &longs;oluitur, quia aer fluidus non &longs;olùm &longs;upremus, & flammæ incumbens, &longs;ed etia&mtail; lateralis, & infimus ob eius grauitatem ad modu&mtail; &longs;iphonis, vellibræ non pote&longs;t contundere flammam, &longs;ed eam &longs;ursùm exprimere, & impellere debet, at­que aer &longs;upernus nece&longs;&longs;ariò ad latera excurrere de­bet, & tran&longs;itum minùs pondero&longs;æ flammæ a&longs;cenden­ti concedere; nec ob&longs;taculum aliud ei inferet, præ­terquàm contu&longs;ionem &longs;upremæ aciei flammæ, vt ni-mirùm efficiatur vertex eius aliquo pacto rotundus, & contornatus, ni&longs;i adfuerit noua alia cau&longs;a motum eius accelerans, à qua proindè eius vertex acumi­nari pote&longs;t, vt &longs;uperiùs dictum e&longs;t.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Pergamus modò ad po&longs;tremam difficultatem ab eodem authore allatam. inquit enim: &longs;int duæ pilæ

æneæ, vna &longs;olida exigui ponderis, altera maioris, &longs;ed reple­ta inclu&longs;o aere, hæ&longs;ine dubio a&longs;cendit &longs;uper aquam, non item minor, &longs;i ergo aqua deorsùm tendens exprimit alteram pilam, cur non reliquam? non igitur pila mouetur &longs;ursùm, quia exprimitur, &longs;ed quia in &longs;e habet aerem natura &longs;ua le­uem. Et huic profectò argumento nil aliud re&longs;ponde­re po&longs;&longs;um, &longs;ed tantùm monere authorem eius &longs;e no&ntail; e&longs;&longs;e &longs;atis memorem doctrinæ Archimedis, ex qu&atail; deducitur ingentem pilam æneam excauatam, & ae­re plenam minùs ponderare, quàm moles aquæ ei æ­qualis, & ideò grauitas aquæ maior velut in libr&atail; &longs;ursùm eleuare debet minus pondus prædictæ pilæ æne-aereæ, cum verò comparatur ænea pila &longs;olida licèt paruula &longs;it, illa tamen grauior e&longs;t multò magis, quàm &longs;it moles aquæ huic pilulæ æqualis, cùmque comparatio fieri debeat inter duas moles æquales &longs;olidi nempè demer&longs;æ pilæ æneæ cum mole fluidi am­bientis ei æquali, quia exce&longs;&longs;us ponderis penès pi­lam æneam exi&longs;tit, nece&longs;&longs;ariò maior eius grauitas præ­ualebit, ideòque mergetur, & ad fundum de&longs;cendet, ex quo patet prædictum argumentum non probar&etail; pilam &ecedil;ne-aeream vim leuitatis in &longs;e habere.

Eiu&longs;dem authoris no­ua difficul­tas.

Sed reijci­tur.

Tandem oper&ecedil;pretium erit di&longs;&longs;oluere nouas diffi-cultates à pr&ecedil;claro authore euulgatas, qu&ecedil; ab hac ex­perientia de&longs;umuntur; &longs;it fi&longs;tula vitrea RSVX cuius latitudo &longs;it duorum, vel trium digitorum, altitudo verò &longs;it vnius, vel alterius cubiti, repleaturque aqua, &longs;ed remaneat in eius vertice portio aliqua aeris vni­us, vel alterius digiti, po&longs;tea foramine RX perfectè occlu&longs;o, vel palma manus, vel operculo aliquo re­uoluatur fi&longs;tula vt eius infima ba&longs;is SV in &longs;upremolo­co emineat, videbimus aerem è fundo RX &longs;ursù&mtail; a&longs;cendere, atque incuruari ad modum arcus, ex par­te &longs;uperiori ABC, & è contrà ex parte infima AGC, aut explanari, vel etiam cauitatem aliquam ad mo­dum &longs;cutellæ acquirere. Hinc prædictus Author in­fert certè deduci aerem &longs;ursùm in præ­

dicta fi&longs;tula a&longs;cendere propria virtut&etail; intrin&longs;eca leuitatis non per extru&longs;ionem factam ab aqua ambiente; quia, inquit ip&longs;e, aer &longs;upernè fastigiatur ad modum di­&longs;culi, vt faciliùs peruadat aquam, & qua&longs;i perforet illam, quia aer est, qui turge&longs;cendo &longs;ursùm aquam introit, & cedere &longs;ibi cogit qua&longs;i cuneo in illius medio adacto, alio quin &longs;i idcircò aer &longs;ursùm tendit quia ab aqua de­orsùm tendente extruditur in &longs;uperiora, aqua potiùs peruaderet cuneatim aerem; vt con­tingit in pluuia, vel &longs;altem retunderet &longs;uper­nè illius tumorem, & infernè illum qua&longs;i forcipe comprimens constringeret ad figuram conoidem eius partem infimam.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Alia argu­menta pro leuicate po­&longs;itiua desump ta à pulcher rimo expe­rimento.

Pro re&longs;olutione harum difficultatum priùs metho-do generali demon&longs;trabimus &longs;uppo&longs;ito quòd aer i&ntail; aqua a&longs;cendat non virtute propriæ leuitatis, &longs;ed per extru&longs;ionem medij fluidi tunc figura aeris a&longs;cenden­tis per aquam nece&longs;&longs;ariò erit conuexa &longs;upernè, & in­feriùs excauata, & è contrà &longs;uppo&longs;ito quòd aer inter­no principio leuitatis per aquam a&longs;cenderet, deberet figura aeris a&longs;cendentis tumorem, & rotunditate&mtail; habere tùm ex parte &longs;uprema, tùm ex parte &longs;ubiecta.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXII.

Et primo o&longs;tendendum est, quòd quodlibet fluidum intra aliud fluidum tran&longs;latum &longs;iuè virtute propria, &longs;iuè alie­na violentia impul&longs;um, dummodò eius partes non di&longs;­&longs;ipentur in ip&longs;o fluido in quo mouetur, &longs;ed &longs;e mutuò contingant, & vniantur, nece&longs;&longs;ariò tumorem, & rotundam figuram acqui­ret in parte anteriori mo­tus eius.

QVodlibet fluidum homogeneum naturali in&longs;tin­ctu videtur &longs;ponte coale&longs;cere, ac &longs;imul in &longs;uo toto partes &longs;uas conglutinare, vt videmus partes ae­ris libentèr, & auidè vici&longs;&longs;im vniri, & difficiliùs ab inuicem di&longs;trahi &longs;epararique, &longs;ic quoque partes aqu&ecedil; vniuntur, conglobanturque &longs;phæricè quotie&longs;cumque &longs;ibi mutuò approximantur, itaut ex duabus guttulis vna &longs;uper aliam excurrendo, & &longs;e mutuò amplecten­do vnicam ampliorem guttam con&longs;tituant, e&longs;tque tàm tenax huiu&longs;modi vnio, & vinculum partium aquæ, vt &longs;i contingat aquæ guttam pendentem di&longs;trahi ab ali­qua violentia, illa attenuatur, & gracile&longs;cit elonga­turque, & denuò ce&longs;&longs;ante violentia re&longs;tringitur re­colligitur, conglobaturque, &longs;ic paritèr videmus a­quam ad membranæ &longs;ubtili&longs;&longs;imæ exten&longs;ionem redigi circa aerem &longs;pumam componentem, vnde con&longs;tat partes aquæ inter &longs;e vici&longs;&longs;im colligari vinculo quodam: id ip&longs;um ob&longs;eruamus in vitro, & metallis fu&longs;is. Qua­li&longs;cumque igitur &longs;it cau&longs;a huius vinculi, & tenacita­tis partium homogenearum eiu&longs;dem fluidi, vel quia ab aliquo glutine, &longs;eù vi&longs;co&longs;itate vniantur, aut ab ali qua alia cau&longs;a partes eiu&longs;dem fluidi &longs;e niutuò am­plexentur, & connectantur, certum e&longs;t tamen veram e&longs;&longs;e prædictam vnionem, quotie&longs;cumque fluidum intr&atail; aliud fluidum alterius naturæ collocatur, vt oleu&mtail; intra aquam, vel aer intra quodlibet aliud fluidum, non di&longs;&longs;ipabitur, &longs;ed tenaci quadam vnione conglo­babitur, licet in motu poterit aliquo pacto eius figu­ra rotunda alterari. hoc autem non contingit in om­nibus fluidis cuiu&longs;cumque naturæ &longs;int, nam aqu&atail; intra vinum, & metalla fu&longs;a inter &longs;e commixta no&ntail; &longs;egregantur; &longs;ed facilè commi&longs;centur, confundun­turque inter &longs;e. Et in hi&longs;ce aduertendum e&longs;t adductam ex perientiam locum non habere, &longs;ed tantummodò in fluidis priùs expo&longs;itis non homogeneis inter &longs;e.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Supponamus igitur fluidum ABC, verbi gratia ae­rem, vel hydrargyrum, moueri vi intrin&longs;eca, velvio­lenter impul&longs;um in aqua intra fi&longs;tulàm &longs;trictam RSVX contenta à termino B versùs E: & quia &longs;patium DN LF vbi fluidum ABC tran&longs;portari de­

bet, iam repletum, & occupatum e&longs;t à medio fluido aqueo, hoc autem vt lo­cum cedat &longs;ubintranti fluido ABC, ne­ce&longs;sè e&longs;t vt hinc di&longs;cedat transferatur­que ad occupandum illud &longs;patium, quod derelinquitur à fluido ABC, cùmqu&etail; corpus ABC vnionem &longs;eruet, nec di&longs;&longs;i­petur, igitur anterius medium fluidum debet per eius latera obliquè excur­rere ad occupandas partes po&longs;ticas derelictas à flui­do ABC, &longs;cilicèt fluidum ENDB mouebitur ad partem &longs;ini&longs;tram versùs A, & medium fluidum BFLE moue­bitur ad partem dexteram versùs C, eruntque prædi­cti motus non æquidi&longs;tantes axi EB, &longs;ed erunt incli­nati per lineas obliquas vt &longs;unt EA, & EC, & hoc nece&longs;&longs;itate quadam contingit, quia fluidum è loco ampliori SEBD pertran&longs;ire debet per angu&longs;tam viam AO, & reliqua fluidi medietas VEBF pariter ab am­plo &longs;patio perduci, ac pertran&longs;ire debet per &longs;trictum locum CP, & huiu&longs;modi viæ angu&longs;tæ cùm &longs;int lateri va&longs;is adhærentes, nece&longs;sè e&longs;t vt motus, & fluxus aqua à &longs;itu B versùs O, & P obliquo itinere fiat impellen­do, contundendo, & confricando &longs;uperficiem cor­poris ABC, quod compre&longs;&longs;ioni cedit ob eius fluidi­tatem, igitur ABC accommodari debet &longs;ituationi obliquæ pre&longs;&longs;ionis corporum excurrentium à &longs;upre­mo loco B versùs O, & P, quapropter nece&longs;&longs;itat&etail; quadam acquirit fluidum ABC tumorem, & conuc-xitarem cuins vertex in parte eius anteriori B exi&longs;tit. Et quia fluidum ABC, vt dictume&longs;t, diuer&longs;æ natur&ecedil;, ac con&longs;i&longs;tentiæ e&longs;t ab ip&longs;o fluido ambiente in quo mo­uetur, ideò non commi&longs;centur, neque vici&longs;&longs;im confun­duntur inter &longs;e, &longs;ed quodlibet eorum &longs;eruabit vnio­nem, & connexionem &longs;uarum partium homogenea­rum. Hinc con&longs;tat quòd fluidum ABC dum fertur à B versùs E, nece&longs;&longs;ariò acquirit figuram tumidam, & acuminatam versùs anteriorem partem motus eius, & hoc &longs;emperverificari debet, à quacumque virtute motiua transferatur, &longs;iue ab intrin&longs;eca, & naturali, &longs;iuè ab externa: & hoc propo&longs;itum fuerat.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXIII.

Po&longs;ito quòd fluidum violenter &longs;ursùm exprimatur à fluido amibente grauiori, diuer&longs;æque con&longs;istentiæ, infima a­&longs;cendentis fluidi &longs;uperficies explanata, vel concaua erit.

DEinde fluidum ABC, oleum v. g. demer&longs;um in fundo alterius flui­di grauioris, & diuer&longs;æ con&longs;i&longs;tentiæ, vt e&longs;t aqua intra fi&longs;tulam &longs;trictam SX con­tenta, & &longs;uppo&longs;ito, quòd idip&longs;um flui­dum ABC non a&longs;cendat in ip&longs;a aqua à vi natiuæ eius leuitatis translatum, &longs;ed expul&longs;um per extru&longs;ionem à maiori gra­uitate fluidi aquæ ambientis. O&longs;tenden­dum e&longs;t in hac hypothe&longs;i infimam, & po&longs;ticam partem AGC eiu&longs;dem olei a&longs;cendentis nece&longs;&longs;ariò explana­tam, imò excauatam fore; quia ex hypothe&longs;i pondus &longs;pecificum aquæ ambientis &longs;uperat &longs;pecificam gra­uitatem olei ABC; iam &longs;i e&longs;t moles aquæ collateralis FQPC æqualis medietati olei BGC, proculdubio aqua FQPC grauior erit oleo BGC, vel &longs;i moles in&ecedil;­quales &longs;unt, aquæ momentum &longs;uperat olei momentum, hi&longs;ce verò inæqualibus ponderibus ineumbunt, & &longs;ubijciuntur moles aquæ æque ponderantes, vel æ­qualium momentorum, ergo in &longs;iphone compo&longs;ito ex cylindri portione aquea VXKL, & ex cylindri portione EIKL compo&longs;ita ex aqua, & oleo inæqua­liter premuntur partes aquæ &longs;ubiectæ GPXI. quæ li­bram con&longs;tituunt, nempè aqua CPXK maiori ni&longs;u comprimitur ab aqua FQPC, quam aqua GCKI pre­matur ab oleo BGC minus graui, & ideò ex coroll pr. 10. oleum BGC &longs;ursùm impelletur ab aqua &longs;ubiecta GIKC, & talis expre&longs;&longs;io fiet (ex prop. 51.) tanta vi, quanta e&longs;t grauitas exce&longs;&longs;us ponderis aquæ FQPC &longs;upra grauitatem olei BGC. præterea quia aqua in­ter EB, & LC dum fertur deor&longs;um ad occupandu&mtail; &longs;patium ab a&longs;cendente oleo derelictum, nece&longs;&longs;ariò comprimit contunditque &longs;uper&longs;iciem collaterale&mtail; olei BC non duri, &longs;ed cedentis, e&longs;tque motus obli­quus per &longs;u perficiem decliuem BC, ergo &longs;patiu&mtail;, &longs;eù alueus, per quod incumbens aqua pertran&longs;ir&etail; debet comprehen&longs;um à &longs;uperficie aquæ FCK dire­cto, & non impedito motu fluentis, & inclinatam de­cliuemque olei BC &longs;uperficiem, continentèr magis con&longs;tringatur angu&longs;teturque, & proinde incumbens aqua velociori motu, & ideò impetu, & vi maiori fluere cogatur per angu&longs;tias C, quàm per amplu&mtail; alueum BFque quare oportet vt vehementiùs, & ma­iori impetu, & vi pars olei versùs C deorsùm com­primatur, contundaturque quàm reliquæ partes olei propinquiores vertici eius B, è contra aqua &longs;ubiecta CKIG reflectitur &longs;ursùm, impellit, atque contundit infimam ba&longs;im olei GC ea vi, & impetu quo collate­ralis aqua FCPQ exce&longs;&longs;u &longs;uæ grauitatis &longs;uperat &longs;pe­cificam olei pondero&longs;itatem. Patet ergo quod à dua­bus viribus contrarijs, veluti prælo, comprimitur oleum BCG &longs;upernè ab impetu aquæ obliquè de&longs;cenden­tis per BC, & infernè à vi aquæ reflexæ oleum &longs;ursum impellentis, cùmque vis, & compre&longs;&longs;io, quæ &longs;upernè infertur, inæqualis &longs;it, vehementiori, & validiori vi facta propè terminum C, & debiliori, ver&longs;us verticem B, impul&longs;us verò &longs;ubiectæ aquæ IKCG licèt vnifor­mis &longs;it vbique, nihilominùs propter minorem de&longs;cen­dentis aquæ ob&longs;i&longs;tentiam in B, quàm versùs C &longs;it vt vehementiùs oleum impellatur contundaturque à &longs;ubiecta aqua reflexa versùs axem IG vbi ni&longs;um con­trarium debiliorem offendit quàm versùs latera A, & C, & propterea &longs;uperficies &longs;ubiecta olei AGC exca­uata erit ad modum &longs;cutellæ, & hoc quidem nece&longs;­&longs;ariò efficietur non à vi intrin&longs;eca, & naturali leuita­tis ip&longs;ius olei, &longs;ed à &longs;uppo&longs;ita energia grauitatis fluidi ambientis, quod fuerat demon&longs;trandum.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXIV.

Si fluidum &longs;ponte à virtute intrin&longs;eca intra aliud fluidum diuer&longs;æ con&longs;istentiæ moueatur, in parte po&longs;teriori, &longs;eù termino à quo, &longs;ui motus, non erit excauatum, &longs;ed tumidam, & conuexam figuram acquiret.

SVpponamus &longs;ecundo loco fluidum

ABC, quod &longs;it aqua, grauius e&longs;&longs;&etail; ambiente fluido (quod &longs;it v. g. oleum) manife&longs;tum e&longs;t aquam ABCH deorsùm in oleo de&longs;cendere ab I versùs E ab in­trin&longs;eco principio &longs;uæ grauitatis impnl­&longs;um. Dico iam quod eadem aqua in par­te po&longs;tica &longs;ui motus H, &longs;cilicèt versùs terminum à quo &longs;ui motus, non erit ex­cauata ad modum &longs;cutellæ, &longs;ed tumida, & conuexa erit. Quia cum primo aqua ABCH demergitur in­fra olei libellam RX, & inchoat pro&longs;equiturque &longs;uum de&longs;cen&longs;um, nece&longs;sè e&longs;t vt oleum &longs;ubiectum AEC è &longs;uo loco continenter recedat, & recurrat ad replen­dum locum po&longs;ticum AMKC ab aqua derelictum; er­go aqua AHCB, & oleum ambiens motibus contra­rijs agitari debent, nempe aqua de&longs;cendet dum am­biens oleum a&longs;cendit, igitur ratione motus, oleu&mtail; po&longs;ticè recurrens non impellet aquam ictum fugien­tem, nec proinde eius figuram AHC contundere, & explanare poterit. præterea aqua ABCH habet vim &longs;e mouendi deorsùm in oleo, hoc verò nullam facul­tatem &longs;e mouendi deorsùm in eodem oleo habet, cum in fluido &longs;ui generis iners æquilibretur, ergo hoc nomi­ne pariter aqua ictum fugiens, immò non impul&longs;&atail;, nec percu&longs;&longs;a ab oleo po&longs;ticè recurrente non poterit contundi, nec explanari, & hoc experientia patet, nam &longs;i pila dura capillitium è filis &longs;ericis tenui&longs;&longs;imis &longs;ibi annexum habuerit, & intra aquam filo deorsùm, &longs;ursùm, vellateraliter trahatur nunquam po&longs;ticum capillitium contundetur explanabiturque, dum vni­formi, non verò retardata velocitate pila in aqu&atail; mouetur. & ab hac experientia|luculenter euinci­tur &longs;omnium illorum, qui aiunt ad vitandum vacuum rapidi&longs;&longs;imo motu oleum po&longs;ticè recurrere, & &longs;ic po&longs;­&longs;e aquæ &longs;uperficiem contundere, & explanare. Qua­propter aqua excepto &longs;implici contactu in &longs;uperficie AHC nullam contu&longs;ionem, aut percu&longs;&longs;ionem patie­tur ab oleo &longs;uperincumbente MACK, igitur nece&longs;sè e&longs;t vt aqua in AHC retineat eamdem figuram, quam priùs habebat, &longs;ed eius figura intra oleum vnita, & contornata e&longs;&longs;e &longs;olet ob naturalem partum eius con­nexionem, & vinculum, & ob compre&longs;&longs;ionem vn­dequaque factam à fluido ambiente, vt dictum e&longs;t. igitur dum aqua ABC de&longs;cendit intra oleum po&longs;tre­ma eius ba&longs;is AHC, &longs;cilicèt versùs terminum à quo motus inchoat, eius figura debet e&longs;&longs;e tumida con­uexa, & contornata, cum è contra eadem aqua a&longs;cen­dens intra mercurium &longs;i extruderetur à fluido ambi­ente nece&longs;&longs;ariò eius po&longs;tica ba&longs;is versùs principium motus non tumida, &longs;ed excauata e&longs;&longs;e debuerat, & hæc omnia o&longs;tendenda fuerant.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Ex prop. 73.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXV.

Si fluidum à principio intrin&longs;eco moueatur intra aliud flui­dum diuer&longs;æ con&longs;istentiæ, quod valdè rarefieri, & co­den&longs;ari queat, tunc multò magis tumida efficie­tur pars postica fluidi decurrentis.

ET hoc quidem verum e&longs;t quando fluidum am­biens, in quo aliud fluidum mouetur &longs;ursùm, vel deorsùm, non patitur &longs;en&longs;ibilem conden&longs;ationem, vel rarefactionem, veluti e&longs;t oleum, aut aqua; at &longs;i valdè rarefiat conden&longs;eturque, vt aer propter velo­ci&longs;&longs;imum ca&longs;um aquæ AHCB remanet aer po&longs;ticus MACK valdè rarefactus, ideoque inhabilis vt in&longs;e­qui po&longs;&longs;it aquam cadentem, & proindè nedùm aer incumbens guttam aquæ de&longs;cendentem in H no&ntail; percutiet, cùm è contrà, ne ibidem, (vt vulgò credi­tur) vacuum remaneat eius vertex tumidus H valdè eleuabitur prominebitque & &longs;ic videmus guttas plu­uiales &longs;ecum trahere veluti caudam aqueam gracilem, tantùm abe&longs;t vt po&longs;ticè contu&longs;ionem patiantur, aut excauentur, & hoc clariùs percipitur &longs;i pila aliqu&atail; lignea, & dura, quæ habeat comam ex filamentis, &longs;eù pilis exili&longs;&longs;imis, & nullius ferè ponderis compo&longs;itam cadat deorsùm in aere, tunc enim pili &longs;upremi a&longs;&longs;ur­gunt efficiuntque veluti caudam fluctuantem, non autem comprimuntur contundunturque versùs &longs;u-premam partem ip&longs;ius pilæ, quod e&longs;t &longs;ignum euidens nullam vim compre&longs;&longs;iuam pati ab aere &longs;uperincum­bente.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXVI.

Si oleum, vel aer a&longs;cenderet in aqua &longs;ponte à vi &longs;uæ leui­tatis impul&longs;us non po&longs;&longs;et eius ba&longs;is excauari ad in&longs;tar &longs;cutellæ.

TAndem demon&longs;trandum e&longs;t po­

&longs;ito, quòd aer, vel oleum ABCH a&longs;cenderet in ip&longs;a aqua à propria, & intrin&longs;eca virtute leuitatis impul&longs;um, quod e&longs;&longs;et ab&longs;olutè impo&longs;&longs;ibile, vt e­ius ba&longs;is infima excauata e&longs;&longs;et ad mo­dum &longs;cutellæ; quia ex aduer&longs;arij hypo­the&longs;i oleum ABCH a&longs;cendit in aqua contenta in fi­&longs;tula &longs;tricta RSVX propria virtute leuitatis ab Iver­sùs E, nec ab aqua infima impellitur exprimiturque fursùm, ergò aqua MACK, quæ currit ad replendum &longs;patium derelictum ab oleo cum &longs;it ex &longs;ui natura gra­uis exercet vim &longs;ui ponderis ab H ver&longs;us I premen­do præcisè &longs;uper fundum vitri RX, & nullo pacto vim exercere pote&longs;t &longs;ursùm abl versùs H, hoc enim e&longs;&longs;et contra grauium naturam, & contra ip&longs;am aduer&longs;arij hypothe&longs;im. Præterea quia oleum ABCH, & aqua ambiens motibus contrarijs agitari debent, nempè oleum, vt leue, a&longs;cendet dum aqua ambiens de&longs;cen­det, igitur non &longs;ibi occurrunt, & aduer&longs;antur, &longs;ed ab inuicem conantur recedere; quare ratione motus aqua inferiùs, & po&longs;ticè recurrens non impellet oleum ictum fugiens, nec proindè eius figuram AHC con­tundere, & explanare pote&longs;t. Igitur in hoc ca&longs;u duo impetus inter &longs;e contrarij, & ab inuicem receden­tes reperiuntur leuitatis olei, nimirùm, &longs;ursùm ab H versùs E, aquæ verò conatus inferiùs tendentis ab H versùs I, igitur hæc duo corpora oleum AHCB, & aqua &longs;ubiecta MACK &longs;e mutuò tantummodò tan­gent placidi&longs;&longs;imo amplexu ab&longs;que vlla pugna, & re­pul&longs;u, vt nimirùm aqua oleum non impellat, neque hoc illam repellat, igitur oleum ABCH multò minùs comprimi, ac contundi debetin H ab aqua &longs;ubie­cta deorsùm premente, quàm contundebatur po&longs;ticè ab oleo incumbente, quando nimirum intra oleu&mtail; de&longs;cendebat, & pondus eiu&longs;dem olei incumbentis patiebatur (in vtroque enim ca&longs;urecur&longs;us fluidi ad &longs;patium replendum æquè reperitur, & proindè ne­que nocet, neque adiuuat prædictum effectum) &longs;ed ex antepræmi&longs;&longs;a propo&longs;itione aqua per oleum deci­dens à vi natiua grauitatis impul&longs;a retinet tumorem eleuationemque conuexam in po&longs;tica parte eius mo­tus, igitur multò magis eleuari deberet tumor i&ntail; oleo per aquam a&longs;cendente in parte po&longs;teriore mo­tus eius &longs;i ab intrin&longs;eca leuitate eleuaretur, qua pro­ptèr erit omninò impo&longs;&longs;ibile, vt oleum, vel aer dum a&longs;cendit per aquam, excauetur in parte infima eius ba&longs;is, quando nimirùm &longs;ursùm fertur ab interno prin­cipio leuitatis, quod demon&longs;trandum fuerat.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

In prop. 7.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

His præmi&longs;&longs;is examinari modò debent &longs;igillati&mtail; oppo&longs;itiones &longs;uperiùs adductæ.

PROP. LXXVII.

Et primo loco dieo, quòd figura inflata, conuexa, & acumi­nata quam aer acquirit in fi&longs;tula aqua plena in parte an­teriori eius motus dum &longs;ursùm a&longs;cendit, non e&longs;t argu­mentum efficax, & euincens aerem &longs;ursùm moueri à principio intrin&longs;eco &longs;uæ leuitatis.

QVia demon&longs;tratum e&longs;t corpora fluida cedentia,

& homogenea &longs;i moueantur intra aliud cor­pus Huidum &longs;iue propria, & intrin&longs;eca virtute moti­ua, &longs;iue ab impul&longs;u facto à cau&longs;a extrin&longs;eca, aut ab ip&longs;o medio, nece&longs;&longs;ariò in anteriori parte motus il­lius tume fieri, contornari, & aliquanti&longs;per acumina­ri debere, quaproptèr tumor, qui in aere a&longs;cenden­te peraquam ob&longs;eruatur, neque inuat, neque nocet, nec &longs;uadet, neque di&longs;&longs;uadet leuitatem po&longs;itiua&mtail;. Mirum tamen e&longs;t non animaduer&longs;am fui&longs;&longs;e cau&longs;a&mtail; cauitatis eiu&longs;dem aeris in parte po&longs;tica eius motus, à qua cauitate, &longs;iut o&longs;ten&longs;um e&longs;t, euidentèr deduci­tur impo&longs;&longs;ibile e&longs;&longs;e aerem ab intrinfeco principio le­uitatis &longs;ursùm ferri, &longs;ed potiùs per extru&longs;ionem me­dij fluidi &longs;ursùm eleuari.

Prop. 72.

Cùm po&longs;tea in&longs;tat aduer&longs;arius aerem, dum per a­quam a&longs;cendit, acumen eius &longs;ursùm porrigere, vt fa­ciliùs terebrare, & perforare aquam vi &longs;uæ leuitatis po&longs;&longs;it. Hoc profectò negatur, quia licèt aer non &longs;it leuis, &longs;ed per extru&longs;ionem à medio fluido &longs;ursù&mtail; expellatur, efformare debet quoque eminentiam il­lam contornatam, & acuminatam, vt demon&longs;tratum e&longs;t.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sed vtile erit parumpèr circum&longs;tantias huius ex­perienti&ecedil; accuratiùs perpendere, inquit enim, par­tem fistulæ &longs;uperiorem conuerte deorsùm, & erige fi&longs;tulam perpendicularitèr ad horizontem, videbis enim aerem, qui in fundo fi&longs;tulæ habuerat formam cylindri occupantem totam cauitatem fistulæ in latum mox a&longs;cendere, & &longs;ic a&longs;cendere, vt &longs;e coarctans extendat in longum, & &longs;uperiorem cylindri illius &longs;uperficiem, quæ plana erat ad modum di&longs;culi, iam conoidem factam e&longs;&longs;e. Itaque hic author

cen&longs;et quòd quando fi&longs;tula RV perpen­dicularitèr ad horizontem eleuatur, ae­rem ROPX, quidum &longs;upernè con&longs;i&longs;te­bat cylindricam formam habebat, etiam in hoc &longs;itu infimo per&longs;euerare po&longs;&longs;&etail; per aliquod tempus in eadem figur&atail; cylindrica, quod profectò &longs;i verum e&longs;­&longs;et non facilè reddi ratio po&longs;&longs;et quare, & quemad­modum à compre&longs;&longs;ione aquæ &longs;uperincumbentis pla­na aeris &longs;uperficies OP efficiatur tumida, & conue­xa, veluti e&longs;t ABC. Alia igitur longè diuer&longs;a ratione res &longs;e habet.

Circum&longs;tan­tia notatu di gna in tali experimen­to affertur ab adrio.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXVIII.

Cau&longs;a &longs;eparationis aerei cylindri è fundo va&longs;is e&longs;t pondus aquæ ambientis.

INtelligatur denuò fi&longs;tula RV plena aqua, in qu&atail; exi&longs;tat aereus cylindrus PORX in parte eius &longs;u­

prema operculo XR clau&longs;a, po&longs;tea circa pun­ctum V fixum reuolua­tur deorsum fi&longs;tula tran&longs;­ferendo nimirùm latus VX in locis VF, VG, VH, & VK, manife&longs;tum e&longs;t, quod in &longs;itu VF pro pter va&longs;is inclinationem &longs;uperficies PO aquæ POSV non per&longs;euera­bit in eodem &longs;itu incli­nato, cùm aqua natura­li in&longs;tinctu æquabili &longs;i­tu ad horizontem parallelo di&longs;poni, redigique de­beat, quaproptèr à &longs;itu decliui PO de&longs;cendet inferiùs versùs &longs;uperficiem BDA horizonti parallelam, veluti exigit &longs;itus, & pendentia fi&longs;tulæ VFR. Hinc &longs;equi­tur, vt aqua excurrat ad occupandum &longs;patium ODAR, à quo aer expul&longs;us deueniet ad replendum &longs;patium &longs;upremum ab aqua derelictum, &longs;cilicèt PEBD. Pro­grediamur modò ad &longs;ituationem fi&longs;tulæ horizontalem VG multò magis aqua in&longs;inuabitur infra aerem dila­tando &longs;inum ampliorem ODAIR, & multò magis­incuruabitur aeris &longs;uperficies EBD, tum à vi qua flui­da &longs;e &longs;e connectunt conglobanturque, quotie&longs;cum­que in fluido ip&longs;is hetherogeneo collocantur, cùm ab acce&longs;&longs;u noui aeris expul&longs;i à cauitate infima DAIRO. Poftquàm verò magis fi&longs;tula deprimitur in &longs;itu val­dè inclinato VH eadem ratione profluet aqua versùs partem infimam, & omninò aerem &longs;eparabit, diuel­letque à fundo va&longs;is, & proindè &longs;ubintrabit ad oc­cupandum &longs;patium ODAICHR. Po&longs;tremò perdu­cta fi&longs;tula ad inclinationem omnium maximam i&ntail; &longs;itu VK perpendiculari ad horizontem aqua, quæ iam in&longs;inuata fuerat circa, & infra aerem tumefactum, & contornatum EBDC, tandèm omninò aerem à fundo, & lateribus va&longs;is diuellet, & proindè multò magis de&longs;cen&longs;us, & compre&longs;&longs;io aquæ ambientis per latera va&longs;is, & aeris continuari pote&longs;t; & vniuer&longs;a hæc o­peratio pendet, vt dictum e&longs;t, non ab aere &longs;pont&etail; a&longs;cendente, neque ab eius leuitate, &longs;ed ab exce&longs;&longs;u grauitatis fluidæ aquæ ambientis, quæ in vertigine fi&longs;tulæ nece&longs;&longs;ariò &longs;eparat, atque diuellit aerem à la­teribus, & fundo va&longs;is, & &longs;ic via &longs;ternitur commodi&longs;­&longs;ima, vt continuari, & pro&longs;equi pre&longs;&longs;io aquæ po&longs;&longs;it, vnde aer &longs;ursùm expul&longs;us continuare pote&longs;t eius cur­&longs;um, &longs;i, inquam, hoc ob&longs;eruatum, & adnotatum fui&longs;­&longs;et, proculdubiò ex mutatione figuræ planæ in tumi­dam in aere a&longs;cendente per aquam non deduxi&longs;&longs;et prædictus author aeris leuitatem po&longs;itiuam.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sed po&longs;ito quòd in vehementi&longs;&longs;ima turbinatione retineretur pauli&longs;pèr aqua adhærens fundo &longs;u premo fi&longs;tulæ, & proinde aer infimus &longs;altem per breui&longs;&longs;imum &longs;patium cylindricam formam ORXP retineret, mani­fe&longs;tum e&longs;t, quòd &longs;ubito ce&longs;&longs;ante impetu aqua vt gra­uior aere deorsùm de&longs;cenderet, labereturque, aut in loco intermedio fi&longs;tulæ, aut ad latera, prout vndu­latio partium aquæ eam promoueret, & &longs;ic &longs;emper à de&longs;cen&longs;u grauioris aqu&ecedil; figura tumida, & conuexa aeris a&longs;cendentis crearetur, numquam verò &longs;pont&etail; ab ip&longs;a leuitate aeris.

Re&longs;ponde­tur &longs;ingulis oppo&longs;itioni­bus aduer­&longs;arij.

Cùm verò in&longs;tat: Si idcircò aer &longs;ursùm tendit, quia ab aqua deorsùm tendente extruditur in &longs;uperiora aqua potiùs peruaderet cuneatim aerem, quem admodum aqua decidens extra fistulam &longs;ubiectum aerem perrumpit, non verò illum ambiens intra &longs;e recipit. Hic primò noto, quòd non sen­per aqua cadens aerem penetrat, nam multoties penetratur ab ip&longs;o aere quando nimirùm &longs;cinditur in plures partes, vt contingit in plunia, vel potiùs quando è fene&longs;tra catino aqua proijcitur.

Sic paritèr ma&longs;&longs;a pulueris terre&longs;tris è turris verti­ce proiecta licèt in principio &longs;it vnita, nihilominùs ab aere di&longs;&longs;ipatur, di&longs;pergiturque, idemque accidit in fumo a&longs;cendente per aerem. Secundò noto, quòd partes aeris, vt dictum e&longs;t, &longs;ponte &longs;ua connectuntur colliganturque inter &longs;e, & proinde intra aquam po­&longs;itæ omnes vniri debent, atque &longs;imùl, conglobatæ per aquam a&longs;cendent, non &longs;ecùs, ac partes aquæ in­tra aerem, vel oleum vici&longs;&longs;im vniuntur, congloban-

turque. Et tunc &longs;olummodò ab inuicem &longs;egregantur &longs;ubdiuidunturque, quando medium fluidum vehe­menti, & irregulari motu fluidum per ip&longs;um a&longs;cen­dens, vel de&longs;cendens perrumpit diuiditque, &longs;eù quia non omnes partes prædicti fluidi excurrentis æquali impetu mouentur, vel quia laterales partes fluidi ab a&longs;peritatibus, & contactibus laterum fi&longs;tulæ retar­dantur, &longs;eù ab aliqua alia cau&longs;a detinentur: nil igitur ex hoc pro leuitate po&longs;itiua acquiritur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Subdit po&longs;tea idem author, quòd aqua &longs;upernè re­tunderet aeris tumorem, & infernè illum, qua&longs;i forcipe comprimens, con&longs;tringeret ad figuram conoidem eius partem infimam. Re&longs;pondetur hoc fal&longs;um e&longs;&longs;e, quia vt ia&mtail; demon&longs;tratum e&longs;t nunquam figura aeris per aquam a&longs;cendentis acuminata in eius infima parte effici po&longs;­&longs;et, &longs;ed nece&longs;sè e&longs;t, vt ab impul&longs;u facto ab aqua gra­uiori ibidem excauetur ad modum &longs;cutellæ, & prop­ter occur&longs;um, & ob&longs;taculum aquæ &longs;upremæ dum aer fluidus a&longs;cendit tumorem, & conuexitatem &longs;uper­nè acquirat.

Cùm verò idem author &longs;ubdit, quod &longs;i ca&longs;u copule­tur particula aliqua aeris cum oleo per aquam a&longs;cendente, con&longs;tat quòd huiu&longs;modi aggregatum velociùs a&longs;cendit per aquam. non video quidnam ex hoc deduci po&longs;&longs;it pro leuitate po&longs;itiua, imò nego quod non pos&longs;it reddi phy­&longs;ica, & &longs;olidaratio cur velociùs moueatur coniunctum il­lud ex oleo, & aere, quàm oleum &longs;olum. Et po&longs;tea: neque aquam citiùs de&longs;cendendo expellere quoque citiùs oleum &longs;ursùm cum nec maior moles &longs;it aquæ &longs;upra oleum, quàm an-tea. Primò aio nil referre an moles aquæ &longs;it maior, aut minor re&longs;pectu olei, & aeris, &longs;ed &longs;ufficit vt gra­uitas &longs;pecifica aquæ, multò maior &longs;it re&longs;pectu aggre­gatiex aere, & oleo, quàm re&longs;pectu &longs;olius olei, ita­que in ca&longs;u no&longs;tro moles aquæ, &longs;iue magna, &longs;iue exi­gua, in fi&longs;tula pote&longs;t comparari cum oleo tantùm, vel cum aggregato ex oleo, & aere; modò ex Archime­dis doctrina eadem aqua grauior e&longs;t &longs;pecie aggre­gato ex oleo & aere, quàm oleo &longs;olitario, & quò ma­ior fuerit differentia grauitatum &longs;pecificarum, tantò maior, c&ecedil;teris paribus, e&longs;t velocitas mobilis in fluido, & hinc con&longs;tat quòd ea quæ adducta &longs;unt, vt maximè ab&longs;urda nedum inconuenientia non &longs;unt, &longs;ed è contrà nece&longs;&longs;itate mechanica contingere debent. Po&longs;tremæ oppo&longs;itioni, vbi ait: Nec denique dici pote&longs;t coniunctum ex oleo, & aere e&longs;&longs;e aliquid leuius, quàm aquæ alterum tan­tum in eadem mole, ideoque aquam illud magis in grauita­te excedere, quàm oleum &longs;eorsùm &longs;umptum, & proindè ci­tiùs illius locum occupare velle; nam &longs;i non datur leuitas, & particula aeris habet aliquid grauitatis potiùs ex illa, & oleo factum estcorpus grauius, quàm est &longs;olum oleum. Et hic nil aliud re&longs;pondere po&longs;&longs;um, ni&longs;i quòd huiu&longs;mo­di ratiocinia condonari po&longs;&longs;untijs, qui in doctrin&atail; Archimedis minimè ver&longs;ati &longs;unt. Affertur enim, vt ab&longs;urdum, quòd aggregatum ex oleo, & aere grauius &longs;it abfolutè &longs;olo oleo, quod profectò non negatur, e&longs;t enim veri&longs;&longs;imum, &longs;ed tamen animaduertendum e&longs;t, quod licèt prædictum aggregatum ex oleo, & aer&etail; grauitate ab&longs;oluta magis ponderet, quàm oleum per &longs;e &longs;umptum, tamen &longs;i grauitas &longs;pecifica con&longs;idere­tur, erit aggregatum ex oleo, & aere minùs graue, quàm oleum &longs;olum, quia nempè pondus aggregati ex oleo & aere, minorem proportionem habet ad grauitatem molis aqueæ ei æqualis, quàm pondus &longs;olius olei habeat ad grauitatem aquæ molis prædicto oleo æqualis, &longs;cilicèt &longs;i aggregati ex oleo, & aere grauitas &longs;ubdupla fuerit pondere molis aquæ &longs;ibi æ­qualis, pondus olei &longs;olius maius erit medietate pon­deris molis aquæ oleo æqualis, & hinc &longs;it vt maiori impetu &longs;ursùm per expre&longs;&longs;ionem impellatur aggre­gatum ex oleo & aere à &longs;uperabundanti grauitate aquæ circumfu&longs;æ, quæmaiori differentia &longs;pecificam grauitatem eius &longs;uperat, quàm moueatur oleum &longs;ur­sùm extru&longs;um à pondere minùs excedenti eiu&longs;de&mtail; aquæ ambientis. Et hoc quidem &longs;i ritè percipiatur, tollentur, & euane&longs;cent omnes difficultates, quæ contra prædictam doctrinam afferri po&longs;&longs;unt.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Præter ea, quæ iam dicta &longs;unt affert idem author alia experimenta ex quibus putat euidentèr deduci po&longs;&longs;e exi&longs;tentiam leuitatis po&longs;itiuæ, quia inquit: Cylindrus ligneus è fundo aquæ &longs;ursùm tanto impetu fertur vt multotiès exiliat totus &longs;upra aquam ille igitur &longs;altus in­dicium e&longs;t impetus ab intrin&longs;eca leuitate facti, quia aqua non pote&longs;t illud vltrà trudere quam &longs;it ip&longs;i opus vt locum inferiorem occupet ni&longs;i ip&longs;a &longs;ursùm priùs feratur, quod e&longs;t contra ip&longs;ius grauitatem.

N argu­menta &longs;em Auho is pro leuitate po&longs;itiua.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXIX.

Lignum in aqua a&longs;cendens &longs;altu &longs;upra eius libellam exilit ob impetum acqui&longs;itum in præcedenti motu, licèt per extru&longs;ionem fiat.

PRo re&longs;pon&longs;ione ponamus cylindrum ligneum in fundo aquæ. Dico quòd &longs;i id moueatur &longs;ursùm ab intrinfeca vilenitatis, vel ab extru&longs;ione medij flui­di aquei, nece&longs;&longs;ariò velocitas eius dum a&longs;cendit con­tinentèr augebitur, quia dum &longs;ursùm a&longs;cendit in quo­libet temporis in&longs;tanti, eadem virtus motiua, aut le­uitatis, aut externi impul&longs;us, quæ &longs;emper eadem, & eiu&longs;dem energiæ e&longs;t, pariterque extru&longs;io à medio fluido paritèr efficitur ab eadem virtute impul&longs;iua, quæ e&longs;t differentia, vel exce&longs;&longs;us ponderis aquæ &longs;u­pra pondus ligni a&longs;cendentis, cùmque gradus velo­citatum à ligno acqui&longs;iti ob impul&longs;iones ei illatas non &longs;ubitò extinguantur, &longs;ed per&longs;euerent, vt dictum e&longs;t, igitur &longs;ub&longs;equentes impul&longs;iones imprimuntur ei mo­bili non inerti, &longs;ed iam agitati à præcedentibus im­pre&longs;&longs;is velocitatibus, & proindè &longs;ucce&longs;&longs;iuo incre­mento augebitur gradus impetus eiu&longs;dem ligni a&longs;cen­dentis. Igitur mirum non e&longs;t, cylindrum ligneu&mtail;, quando iam acqui&longs;iuit in&longs;ignem gradum impetus à continuato impul&longs;u, & pre&longs;&longs;ione aquæ circumfu&longs;æ, &longs;iuè ab interna eius leuitate po&longs;itiua, mirum, inquam, non e&longs;t &longs;i ab aqua pro&longs;iliat, & &longs;ursùm extra aquæ &longs;u­perficiem propellatur: non igitur &longs;ignum nece&longs;&longs;arium e&longs;t &longs;altus, & pro&longs;ilitio ligni ab aqua leuitatis eius po&longs;itiuæ, quandoquidem prædictus &longs;altus effici po­te&longs;t in vtraque hypothe&longs;i, &longs;cilicèt &longs;iuè admittatur, &longs;iuè negetur leuitas po&longs;itiua.

Libide vi9.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sed vt apertè inefficacia huius argumenti perci­piatur, po&longs;&longs;umus ij&longs;dem ferè verbis o&longs;tendere fal&longs;um e&longs;&longs;e, quòd à leuitate po&longs;itiua lignum &longs;ursùm impel­latur, ait enim &longs;altum dependere non po&longs;&longs;e ab extru&longs;ione aquæ ambientis, quia aqua non potest illud vltrà trude­re, quàm &longs;it ip&longs;i opus, vt locum inferiorem occupet. Di­cam ego eodem modo contra leuitatem po&longs;itiuam, quod non deberet eius leuitas propellere lignum plùs, quàm requiritrecta di&longs;po&longs;itio, & con&longs;titutio natura­lis, quia nempè (&longs;ubijciam) non pote&longs;t leuitas lignum vltrà &longs;ubleuare, quàm &longs;it ip&longs;i opus vt locum &longs;uperi­orem in aqua occupet, cùm &longs;it nempè leuitas null&atail; alia de cau&longs;a ligno communicata ab ip&longs;a natura, ni&longs;i vt vna pars ligni demer&longs;a &longs;ub&longs;idat, altera verò &longs;upra eam in aere emineat, non verò vt lignum integru&mtail; extra aquam collocetin ip&longs;o nempè aere. igitur con­cedat aduer&longs;arius nece&longs;sè e&longs;t non expul&longs;um fui&longs;&longs;e li­gnum &longs;ursùm à leuitate po&longs;itiua &longs;upra &longs;upremam aquæ libellam, & hinc planè conijciet &longs;ui argumenti inef­ficaciam.

Reterquetur idip&longs;um ar­gumentum contra ad­uer&longs;arium.

Pro&longs;equitur deindè: quando cylindrus erat in fundo nonpote&longs;t inueniri, quæ pars aquæ illum &longs;ursùm trudat non illa, quæ in fundo, &longs;uppono enim perfectum cylindrum phy&longs;icè, & fundum va&longs;is exactè planum adeò vt nulla &longs;en&longs;ibilis pars aquæ interlabi pos&longs;it quamdiù cylinder vi detinetur ibi.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Et hinc apertè conijcio non benè perceptum fui&longs;­&longs;e modum quomodò medium fluidum &longs;ursùm impel­lat extrudatque lignum minùs graue ip&longs;a aqua, & ideò operæpretium erit apertè, & di&longs;tinctè hoc declarare.

PROP. LXXX.

Ni&longs;i lignum, & ambiens aqua collater alis motibus contra­rijs &longs;ursùm, & deorsùm &longs;imul tempore moueri que­ant, numquam lignum in aqua a&longs;cendet.

SIt vas ABCD aqua plenum i&ntail; cuius fundo apponatur pri&longs;ma ligneum EFGB hìc ade&longs;t aqua li­gno incumbens AEFH, atque aqua collateralis HFID, quæ comprimit &longs;ubiectum aqueum pri&longs;ma FICG, Dico primò, quod &longs;uperincumbens aqua AEFH nequaquàm &longs;ursùm impellit &longs;ubiectum lignum, imò id comprimit: neque præterea &longs;uperna collateralis aqua HFID prædictum lignum eleuat, &longs;ed tantummodò æquilibratur cum collaterali aqua AEFH. Tantummodò ad rem no&longs;tram facit aqu&atail;, quæ ad latus ip&longs;ius ligni apponitur, FGCI, & hæc non &longs;emper &longs;ubleuare pote&longs;t lignum BF, ni&longs;i habuerit duas conditiones, primò vt aqua FC de&longs;cender&etail; deorsùm valeat, &longs;ecundò vt eodem tempore eadem aqua lignum GE impellere &longs;ursùm po&longs;&longs;it. At quan­dò huiu&longs;modi motus contrarij ob aliquod impedi­mentum fieri &longs;imùl non po&longs;&longs;unt, omninò lignum quie-

&longs;cet in fundo ip&longs;ius aquæ, quia nimirum locum non habet libræ, aut &longs;iphonis operatio. Hoc autem &longs;ic per&longs;picuum fiet: &longs;upponamus ba&longs;im lignei pri&longs;matis BG perfectè, & exqui&longs;itè tangere fundum va&longs;is BC, &longs;cilicèt &longs;i amb&ecedil; &longs;uperficies fuerint explanatæ, & læ­uigatæ, tunc profectò aqua FC, licèt grauior &longs;it ip&longs;o ligno minimè excurrere poterit deorsùm cùm no&ntail; ad&longs;it aditus inter ligni ba&longs;im BG, & fundum putei: in­nititur igitur atque &longs;u&longs;tentatur maius pondus aqu&ecedil; FC à &longs;oliditate fundi GC eiu&longs;dem putei, quare ne­ce&longs;sè e&longs;t vt eadem aqua collateralis FC omninò quie­&longs;cat, & proindè lignum EG non a&longs;cendet &longs;ursùm, nec expelletur ab aqua collaterali quie&longs;cente, quaprop­ter habebimus libram BC non quidem conuertibilem circa centrum G, &longs;ed &longs;tabilem, & firmam, cum in ea minimè contrarij motus de&longs;cen&longs;us partis GC, & a&longs;cen­&longs;us alterius radij BG fieri po&longs;&longs;int &longs;imùl, & &longs;emel, vn­demirum non e&longs;t lignum GE è fundo va&longs;is non a&longs;cen­dere.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXXI.

Vis motiua eleuans lignum in aqua e&longs;t maius pondus colla­ter alis aquæ, quæ de&longs;cendere pos&longs;it, & præterea mo­tu reflexo infimam ligni ba&longs;im &longs;ursùm impellat.

PRæterea dico, quòd non &longs;ufficit vt aqua collate­ralis FC &longs;olummodò moueri deorsùm po&longs;&longs;it, &longs;ed oportet pr&ecedil;tere a vt reflectatur &longs;ursùm infrà lignum GE ad hoc vtlignum è fundo va&longs;is a&longs;cendat, quod con&longs;tat hac experientia: Perforetur fundum va&longs;is GC tunc profectò aqua FG, & ei &longs;uperincumbens FD profluet de&longs;cendendo per apertum orific ium GC, nec proindè lignum GE &longs;ursum a&longs;cendet, &longs;ed nece&longs;sè e&longs;t ob­turato foramine GC, vt aqua fluere, & in&longs;inuari po&longs;­&longs;it inter pri&longs;matis ba&longs;im BG, & fundum putei, & tune a&longs;cendet lignum, &longs;i nimirùm concipiatur putei fun­dum magis depre&longs;&longs;um vt e&longs;t MK, & aqua FC proflu­

ens repleuerit &longs;patium BMLG ef­ficietur &longs;ipho DKMA cuius vn&atail; parsaquea HK grauìor e&longs;t reliqua parte AL, & proindè maiorem vim compre&longs;&longs;iuam habebit aqua HK, quàm aqua, & lignum AL, & prop­terea deprimetur de&longs;cendendo a­qua FGK eleuabiturque motu contrario aqua LB vnà cum ligno incumbente, nece&longs;&longs;ariò igitur requiruntur hi duo motus contrarij de&longs;cen&longs;us aquæ grauioris FK, & a&longs;cen&longs;us aquæ LB vt lignum eleuari po&longs;&longs;it. Hinc colligitur, quod vis motiua, quæ impellit ligneu&mtail; pri&longs;ma GE &longs;ursùm e&longs;t profectò grauitas aquæ colla­teralis FC, &longs;ed quatenùs moueri, atque de&longs;cendere pote&longs;t, & præterea quatenus &longs;ursùm impellere va­let aquam BL, & huic impul&longs;ui cedere debet minor vis deficientis grauitatis ligni EG, & hæc e&longs;t legiti­ma, & adæquata cau&longs;a, quare lignum à maiori im­pul&longs;u aquæ collateralis prementis &longs;ursùm impelli­tur ab aqua, quæ infra eius ba&longs;im in&longs;inuatur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

His declaratis accedamus iam ad difficultates ad­ner&longs;arij, in quibus &longs;upponit, quòd dum ligneus cy­lindrus GE exqui&longs;ito, & immediato contactu fundo va&longs;is adhæret, ip&longs;umque veluti exo&longs;culatur, licèt vas

repletum aqua fuerit, lignum &longs;ponte &longs;ua, & vi eius leuitatis &longs;ursùm a&longs;cendere deberet. Sed quid facies, &longs;i experimentum huic a&longs;&longs;ertioni refragatur? Et pro­cùl dubio &longs;i experimentum ita &longs;e haberet, vt ab ip&longs;o refertur, &longs;cilicèt &longs;i cylindrus ligneus GE exqui&longs;itè tangens &longs;uperficiem fundi va&longs;is BG complanatam, & l&ecedil;uigatam, e&longs;&longs;etque vas aqua repletum, & nihilo­minus lignum &longs;ursùm a&longs;cenderet, nece&longs;&longs;ariò a&longs;&longs;erere teneremur, & confiteri, lignum, non à principio ex­trin&longs;eco per extru&longs;ionem, &longs;ed à vinaturali leuitatis eius a&longs;cendere.

Experimen­tum fal&longs;um aduer&longs;arij pro leuitate po&longs;itiua.

PROP. LXXXII.

Experimentis euincitur non ob defectum leuitatis po&longs;itiuæ, &longs;ed quia extru&longs;io à medio fluido grauiori fieri non po­test, lignum in aquæ fundo quie&longs;cere.

VErùm quia lignum EG in aqua demer&longs;um non a&longs;cendit è fundo va&longs;is cui adhæret, imò ibidem &longs;i&longs;titur, & quie&longs;cit, igitur non ine&longs;t in ligno cau&longs;a ima­ginata, quæ leuitas po&longs;itiua vocatur. E contrà quo­tie&longs;cumque fieri, & exerceri pote&longs;t extru&longs;io medij fluidi, ide&longs;t quotie&longs;cumque fluidum grauius fluer&etail; pote&longs;t, & in&longs;inuari infra cylindrum ligneum, &longs;emper &longs;ub&longs;equitur effectus a&longs;cen&longs;us illius, at quando (vt in no&longs;tro ca&longs;u accidit) aqua &longs;ubingredi inter duas &longs;uperficies ligni, & fundi va&longs;is non pote&longs;t ob exqui­&longs;itum contactum, & congruentiam, tunc non &longs;equi­tur effectus a&longs;cen&longs;us eiu&longs;dem ligni, veluti in bilance pondus centum librarum non &longs;ubleuabit contrapo&longs;i­tum pondus vnciale quotie&longs;cumque illud impeditur, vt ne queat deorsùm deprimi, igitur vera cau&longs;a a&longs;cen­&longs;us ligni in aqua e&longs;t extru&longs;io facta à medio fluido, non autem leuitas po&longs;itiua in ligno inexi&longs;tens.

Cap. 4. po&longs;i­tiuam leui­tatem non dari.

Porrò hoc experti &longs;umus in Academia Experimen­tali Medicea. Po&longs;uimus pilam li­

gneam G in fundo va&longs;is ABCD, quæ tangebat orificium EF conca­uitatis he mi&longs;phæricæ EIF in fun­do va&longs;is excauatæ, po&longs;teà reple­uimus vas hydrargyro v&longs;que ad &longs;ummitatem AD, nec tamen li­gnea pila G fundum reliquit a­&longs;cendendo &longs;ursùm; & notandum, quòd prædicta pila non arctè orificio va&longs;is adhære­bat, & colligabatur, &longs;ed potiùs facillimè digitis di­moueri contorquerique poterat, vnde conijcitur, quàm debili nexu fundum, aut orificium acumi­natum EF tangebat. quia po&longs;te à in&longs;ignis Peripateticus &longs;u&longs;picabatur, quòd præcipua cau&longs;a detinens ligneam pilam demer&longs;am infra hydrargyrum in fundo va&longs;is erat timor, & abominium vacui, quod effici debui&longs;­&longs;et in illo &longs;patio quotie&longs;cumque pila &longs;ursùm a&longs;cen­deret; proptereà, vt petijt prædictus Philo&longs;ophus perforauimus fundum va&longs;is IH, vt nimirùm è part&etail; &longs;ubiecta aer &longs;uccedere po&longs;&longs;et ad replendum vacuum, & &longs;ie leuitas po&longs;itiua ligni G ab&longs;que vacui periculo commodè &longs;ursùm a&longs;cendere po&longs;&longs;et; hac præparatione facta, illa lignea pila fundum non dereliquit, nec &longs;ur­sùm a&longs;cendit; nec paritèr a&longs;cendit po&longs;tquam foramen Hocclu&longs;um denuò fuit, & cauitas &longs;ubiecta EIF, & &longs;uprema AED repleta hydrargyro fuit. Vnde dedu­cere po&longs;&longs;umus pilam non à po&longs;itiua leuitate eleuari, &longs;ed potiùs ab expre&longs;&longs;ione ambientis fluidi quotie&longs;­cumque excurrere pote&longs;t ab&longs;que impedimento in­fra &longs;uperficiem eiu&longs;dem pilæ.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Perpendamus tandem po&longs;trema verba eiu&longs;de&mtail; Authoris, qui ait: Sed quid dicent aduer&longs;arij, &longs;i in fundo va&longs;is e&longs;&longs;et foramen amplum, angu&longs;tius tamen cylindro, & occlu&longs;um, quod eodem momento aperiretur quo manuseleuat virgam? certè enim aqua efflueret deorsùm, & tamen cy­lindraceum lignum illud tenderet &longs;ursùm. Agno&longs;cant ergò in ligno illo leuitatem aliquam, quæ impetum producendo &longs;ursùm versùs priùs natura mouet, ac pellit aquam, & cau­&longs;aest vt aqua corpus fluidum it a illi cedat, vt &longs;ubintret in illius locum, ne detur vacuum, eamque non exercere gra­uitatem actu, &longs;ed &longs;uperiores quidem aquæ partes impelli à cylindro ligneo, & cedere illi locum digrediendo ad latera, vt locum illarum partium impleant, quæ infernè &longs;ubintrant in locum cylindri. Et hic nil aliud re&longs;pondere po&longs;&longs;u&mtail; ni&longs;i mirari confidentiam, &longs;ecuritatemque qua a&longs;&longs;eri­tur experientia non &longs;icuti reuera &longs;e habet, vtque à quolibet comprobari pote&longs;t, &longs;ed veluti præiudica­ta opinio eis per&longs;ua&longs;erat.

Aliud falsum experimentum ab eodé au­thore allat

Cap. 4. po&longs;i­tiuam leui­taem no&ntail; dari.

Sit igitur vas ABCD in cuius fun;shy;do aperiatur amplum foramen BC, &longs;it po&longs;tea ligneus cylindrus FE, cuius ba&longs;is HE paulò amplior &longs;it foramine va&longs;is, vt nimirum po&longs;&longs;it ip&longs;um præcisè occludere, ob&longs;true­reque &longs;implici contactu; repleatur po&longs;tea vas aqua v&longs;que ad AD, &longs;up­ponit aduer&longs;arius, quòd cylindrus FE non po&longs;&longs;it in fundo va&longs;is deti­neri, ni&longs;i deorsum vi impellatur vir­ga quadam ferrea ML præterea ait, quòd &longs;i occlu&longs;o infimo foramine BC, eodem mo­mento temporis recludatur os infimum, remoueatur­que virga ML, fore vt aqua exeat per infimum os BC, & lignum FE a&longs;cendat &longs;ursùm, quod, &longs;ubdit ip­&longs;e, e&longs;t argumentum certis&longs;imum leuitatis po&longs;itiuæ ciu&longs;dem ligni. Et hic primò ob&longs;eruo contra aduer&longs;arij a&longs;&longs;er­tionem, quòd &longs;i ba&longs;is cylindri HE zona circularis præcisè tangat, & exo&longs;culetur perimetrum orificij putei BC, tunc non requiritur epi&longs;tomium vt aqu&atail; è va&longs;e non effluat, neque requiritur impul&longs;us virgæ LM, vt prohibeatur a&longs;cen&longs;us cylindri FE è fundo va­&longs;is, &longs;ed ibidem quie&longs;cet, veluti &longs;i tenacitèr colliga­tus e&longs;&longs;et ab illo contactu &longs;implici. Imò, quod magis mirere, &longs;i infima zona ba&longs;is HE ip&longs;ius cylindri lignei non perfectè congrueret; neque compleret vndique tangendo orificium infimum BC, &longs;ed per rimulas, vel angulos aliquos aqua deor&longs;um efflueret, tunc neque opus haberemus virga impellente ML vt li­gnum prædictum in fundo va&longs;is retineretur, &longs;ed &longs;pon­te &longs;ua ibidèm quie&longs;ceret, imò &longs;i quis conaretur &longs;ur­sùm trahere prædictum cylindrum FE filo aliquo ML tunc nedùm vt eius ba&longs;im diuelleret à contactu orifi­cij BC, &longs;ed etiam po&longs;t eius &longs;eparationem à fundo per aliquod exiguum interuallum, aliqua renitentia per­&longs;entiretur, et vis aliqua trahens requireretur, aliàs &longs;ponte &longs;ua lignum ip&longs;um decideret denuò ad occlu­dendum va&longs;is orificium BC, Hinc videat aduer&longs;arius quàm iure exclamet, cùm ait: Agno&longs;cant ergò in ligno leuitatem aliquam, &c. quia cum experientia totu&mtail; oppo&longs;itum o&longs;tendat, iurè po&longs;&longs;emus ei reddere verba &longs;ua: Agno&longs;catergo in ligno nullam leuitatem ine&longs;&longs;e.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXXIII.

Supra foramen in fundo putei apertum exercetur compres&longs;io ponderis columnæ aqueæ v&longs;que ad &longs;upremam eius li­bellam exten&longs;æ.

ET profectò ij, qui ver&longs;ati

&longs;unt in hac doctrina hydro­&longs;tatica Archimedea optimè no­runt, quòd quotie&longs;cumque in præ­dicto va&longs;e aqua pleno aperitur­os in eius fundo BC, tunc ade&longs;t cylindrus aqueus IBCK, qui con­primit, & vim facit proprio pon­dere &longs;upra quodlibet corpus im-pediens exitum, ac fluxum prædictæ aquæ, quod qui­libet experiri facilè pote&longs;t &longs;i palma manus occludat infimum va&longs;is orificium BC, percipiet enim compre&longs;­&longs;ionem, & impul&longs;um tanta vi factum quanta e&longs;t gra­uitas cylindri aquei prædicti, & hoc experitur ne­dùm quando palma manus vetat omninò effluxu&mtail; aquæ, quam &longs;i aliquanti&longs;per manus &longs;ubleuetur, vt po&longs;&longs;it aqua effluere. Hoc præmi&longs;&longs;o.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXXIV.

Ex prædicta experientia euidentèr o&longs;tendetur lignum in aqua nullam po&longs;itiuam leuitatem exercere.

SVpponamus cum Aduer­&longs;ario (&longs;i po&longs;&longs;ibile e&longs;t) cy­lindrum ligneum FE &longs;ub a­qua demersum vim exercere, ac tendere &longs;ursùm intrin&longs;eca vi &longs;u&ecedil; leuitatis dum aqua col­lateralis per rimulas infimas H & E effluit è va&longs;e: Sit ve­rò energia leuitatis ligni (vt æquum e&longs;t) certæ, & deter­minatæ men&longs;uræ, quæ expri­mi poterit à pondere corporis P &longs;u&longs;pen&longs;i in libra MO radiorum æqualium; Huic vi leuitatis aduer&longs;atur con­trario ni&longs;u pondus &longs;uperincumbentis cylindri aquei IFGK, quod paritèr intelligatur termino M eiu&longs;dem libræ &longs;u&longs;pen&longs;um. Quoniam vis leuitatis cylindri li-gnei FE in aqua demer&longs;i &longs;emper eadem e&longs;t, nec po­te&longs;t vnquam diminui, cùm &longs;it æqualis vi illius ponde­ris, quod &longs;ufficit ad prohibendum a&longs;cen&longs;um prædicto ligno FE (vt con&longs;tat ex Archimede) & è contrà pon­dus incumbentis cylindri aquei IKGF pote&longs;t &longs;ucce&longs;­&longs;iuè diminui in infinitum prout eius altitudo IF dimi­nuta fuerit, &longs;ublata nimirum aqna è va&longs;e ABD. fiat igitur vis ponderis aquæ IG minor energia leuitatis ligni FE, &longs;cilicèt minor &longs;it pondere P, quia verò mi­nor vis &longs;uperari à maiori debet, igitur nece&longs;&longs;ariò pondus P de primet radium libræ NO, &longs;uperabitque re&longs;i&longs;tentiam diminutæ aquæ IG &longs;u&longs;pen&longs;æ in altera li­bræ extremitate M, &longs;cilicèt lignum FE (quod tange­re orificium va&longs;is HE &longs;upponebatur) &longs;ursùm a&longs;cen­det in ip&longs;a aqua vi maioris &longs;uæ leuitatis, &longs;ed hoc e&longs;t fal&longs;um, & contra &longs;en&longs;us euidentiam, numquam enim prædictus cylindius ligneus fundum de&longs;erit, nec &longs;ur­sùm a&longs;cendit; &longs;i tamen &longs;emper orificio BC in&longs;i&longs;tat, nec incutiatur vt ad latus fundi ba&longs;is transferatur, vbi maior eius ba&longs;is pars in&longs;i&longs;tit fundo &longs;tabili putei, vel cylindrus ip&longs;e tran&longs;uersè fle ctatur. Igitur verum non e&longs;t lignum FE exercere nè minimum gradum impe­tus leuitatis.

Cap 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

De in&longs;idét. fluido lib. 1. prop. 6.

PROP. LXXXV.

Aliter idip&longs;um demonstrare.

II&longs;dem po&longs;itis intelligatur præterea quòd vis leui­tatis prædicti ligni, &longs;cilicèt pondus P æqualis &longs;it energi&ecedil; ponderis incumbentis cylindri aquei IG: tunc quælibet minima vis addita ponderi P deberet eleuare v&longs;que ad &longs;upremæ aquæ libellam cylindrum FE, quod &longs;imilitèr e&longs;t fal&longs;um, debet enim &longs;uperad­di ponderi P aliud pondus R æquale ponderi lignei cylindri FE.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXXVI.

Præterea alio modo idem confirmare.

TAndem (in eadem hypothe&longs;i) &longs;it vis leuitatis po&longs;itiuæ ligni FE minor vi ponderis &longs;uperin­cumbentis cylindri aquei IG. (& maioris claritatis gratia) &longs;upponamus pondus P æquale exce&longs;&longs;ui gra­uitatis aqueæ molis cylindro FE æqualis &longs;upra pon­

dus cylindri lignei prædicti; quia ex Archimede lignu&mtail; FE tanto impetu in aqua ten­dit &longs;ursùm quanta e&longs;t vis gra­uitatis pr&ecedil;dicti exce&longs;&longs;us. Mo­pondus cylindri aquei IG maius e&longs;t pondere P, &longs;cilicèt vi leuitatis ligni FE, igitur prædicta leuitas à pondere aquæ incumbentis &longs;uperabi­tur vtpotè à maiori virtut&etail;, & proindè lignum detinebitur in fundo va&longs;is, nec a­&longs;cendet. Si po&longs;tea eidem termino libræ O &longs;u&longs;penda­tur aliud pondus Q æquale exce&longs;&longs;ui ponderis aquæ IG &longs;upra grauitatem P, patet quod vt &longs;uperetur im­pedimentum, quod reperit lignum FE ip&longs;umque &longs;cendere vetat &longs;ufficiet vis ponderis Q, quæ e&longs;t diffe­rentia ponderis aquæ prementis IG, & leuitatis li­gni FE. Sed hoc e&longs;t fal&longs;um, quandoquidem pr&ecedil;ter pondus Q requiritur etiam pondus R æquale pon­deri ab&longs;oluto cylindri lignei FE, & in&longs;uper requiri­tur pondus P quod vnà cum Q æquantur ponderi a­quæ IG. Quapropter adeò fal&longs;um e&longs;t ligneum cylin­drum FE virtute propriæ leuitatis vim &longs;ursùm exer­cere in aqua, vt potiùs deorsùm premat, vt corpus graue.

Ibidem.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Et hactenùs comparauimus vires comprimentes grauitatis &longs;uperincumbentis cylindri aquei IG & le­uitatis cylindri lignei FE, re&longs;tat modò vt paritèr con­paremus velocitates prædictorum corporum, &longs;cilicèt videndum qua velocitate lignum FE &longs;ursùm à vile­uitatis impellatur re&longs;pectu contrariæ celeritatis, qua aqua ABD per infimum foramen BC effluit: eo pro­pemodum modo, quo pi&longs;ces contra cur&longs;um alicuius fluentis fluminis mouentur, &longs;i enim pi&longs;cis velociùs natat, quàm aqua contrario cur&longs;u currat, procùl du­bio pi&longs;cis re&longs;pectu fundi, & ripæ, & &longs;patij mundani contra a quæ cur&longs;um reuera excurret aliquanti&longs;per, quòd &longs;i prædictæ duæ contrariæ velocitates æquales fuerint, licèt reuera pi&longs;cis agitetur, commoueatur­que &longs;emper in eodem &longs;itu mundani &longs;patij per&longs;i&longs;tet, &longs;i tandèm velocitas pi&longs;cis minor fuerit celeritate con­traria fluentis, licèt pi&longs;cis natet, & verè anterius ex-currat in aqua, nihilominùs retrocedet re&longs;pectu &longs;pa­tij mundani, &longs;ed cur&longs;u magis tardo, & lento, quà&mtail; flumen mouetur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXXVII.

Alia ratione po&longs;itiuam leuitatem non dari o&longs;tenditur.

IT aque eodem modo in va&longs;e ABC aqua pleno, & infernè perforato in B intelligantur demer&longs;i glo­buli aerei, &longs;ed perpendiculariter imminentes &longs;uper infimum foramen B, &longs;cilicèt intra cylindrum a queum DBE, qui ad modum fluminis intra

aquam va&longs;is repleti defluit egre­diturque per foramen B. Et &longs;uppo­namus maiori celeritate, &longs;cilicèt dupla, aquam fluere à D v&longs;que ad B, quàm globus aereus G mouea­tur &longs;ur sùm translatus à naturali eius leuitate, itaut, quando aqua prædi­cti cylindri fluentis tran&longs;it &longs;patium GI debeat aereus globus G &longs;ursùm impelli, & tran­&longs;igere &longs;patium æquale IH &longs;ubduplum ip&longs;ius GI, eo quod medium fluidum in quo globus aereus G a&longs;cen­dit non e&longs;t &longs;tabile, &longs;ed deorsùm defluit, non &longs;ecùs ac flumen, igitur quando aqua &longs;patium GI tran&longs;egerit, globus aereus contrario cur&longs;u medietatem itineris IH perficiet, qua proptèr ex hi&longs;ce duabus contrarijs velocitatibus re&longs;ultabit tertia qu&ecedil; dam celeritas, quæ æqualis erit differentiæ prædictarum oppo&longs;itarum celeritatum, & ideò aer G de&longs;cendet duplo tardiùs aqua ambiente; Quòd verò hoc &longs;it fal&longs;um, experien­tia ip&longs;a docet &longs;inimitùm aqua DE atro colore tinga­tur, vel di&longs;per&longs;o puluere terre&longs;tri pauli&longs;per turbida reddatur, tunc procùl dubio particulæ illæ areno&longs;æ graues, aut ob exiguitatem in ip&longs;a aqua dum quie&longs;cit non de&longs;cendunt, vellento motu deorsùm feruntur a vi maioris grauitatis earum. igitur quando aqua deor­sùm fluit, videtur impo&longs;&longs;ibile vt grauiores particulæ areno&longs;æ minori velocitate transferantur deorsù&mtail;, quàm aqua ip&longs;a in qua degunt, quare bulla aerea G quæ vt leuis &longs;ursùm a&longs;cendere &longs;upponitur, non po&longs;&longs;et pari velocitate &longs;imul cum particulis terreis aquæ tur­bidæ deorsùm de&longs;cendere, &longs;ed hoc e&longs;t fal&longs;um, cum ab&longs;que vlla differentia velocitatis deorsùm feran­tur vnà cum aqua turbida cylindri fluentis, igitur ve­rum non e&longs;t, quòd aer G moueatur &longs;ursùm à vi natu­ralis leuitatis eius translatus, cùm aliundè quando re­uera aer G principium motiuum leuitatis in &longs;e habe­ret non po&longs;&longs;et vllo pacto in aqua ip&longs;um non exercere.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXXVIII.

Confirmatur aerem ab ambiente aqua per extru&longs;ionem &longs;ur­sùm impelli.

EContrà quandò globus aereus G nullam pror­sùs leuitatem haberet, & &longs;olummodò per ex­tru&longs;ionem factam à grauitate fluidi ambientis eleua-retur, nullo pacto in tali ca&longs;u po&longs;&longs;et aqua ab inferiori &longs;itu H &longs;ursùm impellere aerem G, propterea quod aqua DB cogitur excurrere deorsùm per va&longs;is aper­tum foramen B, & ideò non pote&longs;t motu reflexo &longs;ur­sùm impellere aerem G. igitur nece&longs;sè e&longs;t vt globus aereus G deferatur à vi fluentis aquæ, vt ip&longs;a experi­entia o&longs;tendit. Vnde colligitur, quod nullum ex ad­ductis, & excogitatis experimentis v&longs;que adhuc euin­cere per&longs;uadereque pote&longs;t exi&longs;tentiam leuitatis po­&longs;itiuæ, & è contrà &longs;emper multò magis confirmatur, demon&longs;traturque eius non exi&longs;tentia, quaproptèr fa­tendum e&longs;t corpora, quæ leuia appellantur, &longs;ursùm impelli per extru&longs;ionem à fluidis ambientibus gra­uioribus.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sed coronidis loco afferam demon&longs;trationem à me excogitatam, ab&longs;olutè non dari in natura po&longs;itiuam leuitatem, vtque commodiùs hoc efficiam primò nonnullas &longs;uppo&longs;itiones &longs;en&longs;ui manife&longs;tas proponam, & deinceps aliqua lemmata ex principijs mechani­cis de&longs;umpta demon&longs;trabo.

DEFINITIO I.

ET primò noto, quòd corpus &longs;iue &longs;imilare, & ho­mogeneum, &longs;iue heterogeneum, tunc vocatur exi&longs;timaturque rarius &longs;pecie, quàm aliud, quando &longs;nmptis æqualibus molibus eorumdem illud minorem copiam materialis &longs;ub&longs;tantiæ corporeæ, & &longs;en&longs;ibi­lis comprehendit in eodem &longs;patio, quàm i&longs;tud, quòd profectò concipi pote&longs;t, &longs;i intelligatur mino: copia materiei &longs;en&longs;ibilis in maiori &longs;patio corporis rarioris exten&longs;a per interpo&longs;itionem inanium &longs;patiolorum.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

DEFINITIO II.

SI verò moles æquales, &longs;iuè inæquales non con­&longs;iderentur, & raritas in vna earum contenta ma­ior fuerit raritate alterius, tunc dicetur illa raritas ab&longs;olutè maior reliqua, &longs;iuè exce&longs;&longs;us raritatis exten­&longs;iuè in maiori mole multiplicetur, &longs;iuè inten&longs;iuè i&ntail; minori mole augeatur.

Sup. 8.

SVPPOSITIO VII.

PRæterea &longs;uppono ex Ari&longs;totele raritatem alicu­ius corporis multiplicari, & augeri in infinitum po&longs;&longs;e prout &longs;ub&longs;tantialis moles corporea, quæ in eo­dem &longs;patio contine batur, &longs;ucce&longs;&longs;iuè imminuitur, & po&longs;t diminutionem extenditur expanditurque vt re­pleat idip&longs;um &longs;patium, quod prius à non imminuto corpore occupabatur.

SVPPOSITIO VIII.

SVppono præterea, quòd vis quæ requiritur ad &longs;eparanda duo corpora &longs;e mutuò tangentia im­mediato, & exqui&longs;ito contactu, (quod accidit quan­do eorum &longs;uperficies &longs;unt omninò &longs;imiles, & optimè l&ecedil;uigatæ) non e&longs;t infinita, &longs;ed determinata, quia ni­mirùm &longs;en&longs;us euidentia o&longs;tendit, quod &longs;i potenti&atail; motiua augeatur &longs;emper magis, ac magisne dùm cor­pora &longs;e mutuò tangentia &longs;eparantur, & ab inuicem diuelluntur, &longs;ed etiam corpora illa, quæ continu&atail; cen&longs;entur, vt e&longs;t columna marmorea, vel virga me­tallica, tandèm à vi trahente di&longs;trahitur, euelliturque directo motu vna pars ab altera, quæ tenaciori glu­tine vinculoque vniuntur, quàm illa duo corpora &longs;e mutuò tangentia, & &longs;implici contactu vnita.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. LXXXIX.

Verùm prædictam vim, quæ requiritur ad &longs;eparanda duo cor­pora &longs;e mutuò tangentia, pos&longs;ibile e&longs;t mediante libra men&longs;urari hac ratione.

SIt cylindrus CAB cuius ba&longs;is

AB perfecti&longs;&longs;imè explanata, & l&ecedil;uigata congruat exo&longs;cule­turque &longs;uperficiem pauimenti DE, pari diligentia complanatam, & l&ecedil;uigatam, & cautionis grati&atail;, vttuti omninò &longs;imus aerem am­bientem penetrare, ac ingredi non po&longs;&longs;e inter præ­dictas duas complanatas &longs;uperficies po&longs;&longs;ent colliga­ri tùm cylindro, tùm pauimento duæ laminæ vitreæ AB, & DE, aut alterius &longs;ub&longs;tantiæ duri&longs;&longs;imæ, quæ in­&longs;tar &longs;peculi explanatæ, & l&ecedil;uigatæ &longs;int; po&longs;teà com­primantur, vna, &longs;uper alteram intrà aliquod fluidum vi&longs;ibile veluti e&longs;t aqua, vel hydrargyrum, vt nimi­rùm vi&longs;u con&longs;tet nihil omninò intercipi inter prædi­ctas duas &longs;uperficies, dum nimirùm vna earum trahi­tur, vt ab altera diuellatur. Colligetur po&longs;tea cylin-dri extremitas C termino H trochleæ, vel libræ HK radiorum æqualium, cuius centrum I, & reliquo ex­tremo K &longs;u&longs;pendatur pondus N æquale grauitati ab­&longs;olutæ cylindri AC. profectò manife&longs;tum e&longs;t &longs;en&longs;ui non &longs;ufficere pondus N ad &longs;eparandum, & diuellen­dum cylindrum AC à pauimento DE, &longs;ed requiritur aliqua vis multò maior illa, quæ reperiri a&longs;&longs;ignarique poterit, non enim e&longs;t infinita, igitur &longs;i addatur con­tinentèr pondus ponderi termino K tandem deuenie­mus ad pondus aliquod, vt e&longs;t O à quo cvlindrus CA directa tractione diuelli à pauimento poterit. Quia verò duo pondera N, & O directè diuellunt cylindrum AC, & hic re&longs;i&longs;tit &longs;eparationi duabus viribus, pro­prij &longs;cilicèt ponderis æqualis nempè ip&longs;i N, & vi contactus, & repugnantiæ ad vacuum admmittendum. igitur remanens vis ponderis O æqualis erit, & aucta &longs;uperabit vim connexionis duarum &longs;uperficierum &longs;e mutuò exqui&longs;itè tangentium.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sup. 8.

Non defuit tamen qui hunc progre&longs;&longs;um in dubium reuocare au&longs;us &longs;it, & &longs;ic inutilem, ac inefficacem vni­uer&longs;am demon&longs;trationem &longs;ub&longs;equentem redder&etail;, qu&ecedil; in prædicta experimentali operatione fundatur. Nucleus difficultatis talis e&longs;t, non videri po&longs;&longs;ibil&etail; columnam AC vnquam po&longs;&longs;e motu tàm directo &longs;ur­sùm trahi, nec libra, nec trochlea itaut non flectatur inclineturque, & hoc (inquiunt) nullo pacto huma­na diligentia a&longs;&longs;e qui po&longs;&longs;e; imò a&longs;&longs;erere au&longs;i &longs;unt, quòd &longs;i funis HC directè traheretur perpendiculari­tèr nimirùm ad planum horizontis, & ad ba&longs;im DE nunquam à quacumque vi diuelli columna po&longs;­&longs;et, nec&longs;uperari re&longs;i&longs;tentia ad vacuum, quod profe­ctò &longs;ub&longs;equeretur in actu violento &longs;eparationis &longs;u­perficierum AB, & DE. Si verò (aiunt) applicetur vis tran&longs;uer&longs;alitèr, itaut latus BC columnæ angulum con&longs;tituat cum linea tractionis, tunc facilè &longs;eparari, ac diuelli ab inuicem poteruut prædict&ecedil; &longs;uperficies.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Huiu&longs;modi cauillo&longs;a re&longs;pon&longs;io condonari pote&longs;t ijs Philo&longs;ophis, qui mathematices imperiti &longs;unt.

PROP. XC.

Potest facili negotio præcisè innote&longs;cere re&longs;i&longs;tentiailla ab&longs;olu­ta, & totalis, quæ requiritur ad &longs;eparationem illam di­rectam, & ad korizontem perpendicularem efficien­dam ip&longs;ius columnæ à fundo va&longs;is, quotie&longs;cum­que constet quanta vis requiritur adeam &longs;eparandam impetu obliquo ab eodem &longs;olo.

SIt denuò cylindrus AC

cuius ba&longs;is AB l&ecedil;uigati&longs;­&longs;ima, contactu perfecto &longs;uper­ficiem pauimenti DE paritèr l&ecedil;uigatam tangat, & vis M tran&longs;uer&longs;ali directione CM perpendiculariad CB trahat terminum columnæ C, & va­leat huiu&longs;modi potentia diuellere &longs;uperficiem AB ab ip&longs;o pauimento, &longs;itque prædicta potentia M æqualis ponderi R, & quam proportionem habet &longs;emi&longs;&longs;is dia­metri AB ba&longs;is prædictæ columnæ ad &longs;uam altitudi­nem BC, eamdem habeat pondus R ad aliud pondus S. oftendendum modò e&longs;t vim ponderis S æqualem e&longs;&longs;e totali re&longs;i&longs;tentiæ contactus duarum prædictarum &longs;uperficierum, &longs;eù potiùs æqualem e&longs;&longs;e vi, qua vacui re&longs;i&longs;tentia &longs;uperatur, vel potiùs pondus S &longs;ufficer&etail; ad diuellendam columnam à pauimento directa tra­ctione, &longs;cilicèt detinendo, & transferendo ba&longs;im AB &longs;emper æquidi&longs;tantem plano ba&longs;is DE. Quia in actu &longs;eparationis &longs;uperficiei AB à pauimento debet pun­ctum eius B contingere, & inniti ip&longs;i pauimento, & angularitèr &longs;ubleuari terminus oppo&longs;itus A, vnà cum tota ba&longs;is &longs;uperficie AB, efficiendo nimirùm angulum cum pauimenti plano DE; & hic ob&longs;eruari debent loca vbi duæ vires applicantur, &longs;cilicèt re&longs;i&longs;tentia, & eius, quæ eam &longs;uperat, & per quam directionem tra­hunt & vim exercent; & pater, quòd re&longs;i&longs;tentia i&ntail; omnibus punctis inferioris &longs;uperficiei AB exi&longs;tit, sunt­que veluti totidem fibræ perpendicularitèr erect&ecedil; ad planum &longs;ubiectum, quæ cum eo coniunguntur colli­ganturque; è contrà vis mouens M vectem CB adhi­bet circa centrum firmum B, & quia vniuer&longs;a re&longs;i­&longs;tentia vniformiter di&longs;tribuitur per totam ba&longs;is &longs;u­perficiem AB, reducitur, & perindè re&longs;i&longs;tit ac &longs;i i&ntail; centro aggregati prædictarum fibrarum collocat&atail; e&longs;&longs;et, centrum verò omnium fibrarum prædictarum idem e&longs;t ac centrum I, quod e&longs;t centrum eiu&longs;dem ba­&longs;is; quaproptèr maximus conatus vniuer&longs;æ re&longs;i&longs;ten-tiæ ad diuul&longs;ionem exercetur in centro I circuli AB. Habebimus igitur vectem inflexum CBI in quo vis mouens Mapplicatur in C, re&longs;i&longs;tentia verò applicatur in I, & fulcimentum, &longs;eù centrum reuolutionis vectis CBI e&longs;t punctum B quod fixum per&longs;euerat dum cir­ca ip&longs;um motus, & reuolutiones partium vectis fiunt; Quaproptèr, iuxtà leges Mechanices, re&longs;i&longs;tentia to­talis ad diuul&longs;ionem, & &longs;eparationem &longs;uperficiei AB ab ip&longs;o pauimento ad vim mouentem Meamdem pro­portionem habebit, quam vectis longitudo CB ad oppo&longs;itam eius portionem BI, &longs;cilicèt habebit eam­dem proportionem. quam pondus S habet ad pondus R. Verùm pondus R æquale erat potentiæ M. igitur pondus S æquale erit re&longs;i&longs;tenti&ecedil; ab&longs;olutæ, & totali, quam exercet &longs;uperficies AB quando diuelli, & &longs;e­parari debet à &longs;uperficie paui menti tractione directa. Hinc deducitur quòd &longs;i pon­
dus O propo&longs;itionis 89. di­uellit columnam à pauimento directione, & impetu tran&longs;­uer&longs;ali, & perpendiculari ad latus column&ecedil;, poterit nihilo­minùs indagari re&longs;i&longs;tentia ab­&longs;oluta, & totalis contiguita­tis, vel repugnantiæ ad vacuum earumdem &longs;uperfi­cierum, eritque talis vis ab&longs;oluta tantomaior pon­dere O, quantò altitudo columnæ CB maior e&longs;t &longs;e­mi&longs;&longs;e diametri AB, & &longs;ic &longs;ivis transuer&longs;alitèr colum­nam diuellens æqualis e&longs;&longs;et ponderi trium librarum v. g. & altitudo columnæ CB decies maior radio ba­&longs;is, tunc totalis re&longs;i&longs;tentia prædictæ contiguitatis, &longs;eù repugnantia ad vacuuum admittendum, æqualis erit potentiæ ponderis triginta librarum. Quaproptèr con&longs;tat, quòd vis, quæ requiritur ad re&longs;i&longs;tentiam con­tactus directè &longs;uperandam, licètmaior vt plurimùm &longs;it, quàm ea quæ actu exercetur, nihilominùs finita, & determinata e&longs;t, & facili negotio indagari, men­&longs;urarique pote&longs;t. His declaratis pergo ad demon&longs;tran­dum, quòd.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XCI.

Dato quolibet corpore duro homogeneo, aliudilli æquale repe­riri pote&longs;t, cuius raritas ab&longs;oluta ad illius raritatem maiorem proportionem qualibet dataratione maioris inæqualitatis habeat.

SIt cylindrus &longs;olidus ABC, &

quælibet data ratio maioris inæqualitatis T ad V, & fiat RS maior quàm T. reperiri debetcy­linder æqualis ABC cuius rari­tas ab&longs;oluta ad raritatem ABC &longs;it vt RS ad V. Secetur portio cy­lindrica AD, & RX proximè maior quam V, & fiat cylindrus &longs;olidus EF æqualis AD, cuiu&longs; raritas in &longs;pecie ad raritatem ip&longs;ius AC &longs;it vt RX ad V; po&longs;tea fiat alius cylindrus, &longs;iue fluidus, &longs;iue &longs;olidus FG æ­qualis DB, ita vt illius raritas in &longs;pecie ad raritatem eiu&longs;dem AC &longs;it vt XS ad V. igitur duæ antecedentes RX, & XS ad V, &longs;cilicet RS ad V eamdem propor­tionem habebit quam raritas &longs;pecifica aggregati ex EF, & FG ad raritatem AC, &longs;untquè moles EH, & AC æquales, ergo eorum raritates ab&longs;olutæ &longs;unt pro­portionales &longs;pecificis, &longs;cilicèt &longs;e habent vt RS ad V. quod erat, &c.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XCII.

Cylindrum compo&longs;itum ex duobus cylindris inæqualitèr ra­ris transformare in cylindrum &longs;imilitèr excauatum, cuius pars continens homogenea, & æqualis &longs;it. vni illorum, pars verò excauata homo­genea, & æqualis &longs;it reliquo.

SIt datus cylindrus &longs;oli­

dus AC, compo&longs;itus ex duobus cylindris AD, & DB inæqualitèr raris alium cy­lindrum &longs;imilitèr excauatum æqualem, & &longs;imilem illi de­&longs;cribere, cuius pars continens æqualis, & homoge­nea &longs;it ip&longs;i AD, contenta verò æqualis, & homoge­nea &longs;it ip&longs;i DB. reperto centro que cylindricæ figuræ AC coniungantur rectæ AQ, BQ ad terminos lateris cylindri AB, & fiat triangulum ENF &longs;imile, & æqua­le ip&longs;i AQB. po&longs;tea inter AB, & MB reperiantur duæ mediæ proportionales, quarum maior &longs;it PB (vt do­cuimus lib. 5. conic. Apoll.lemm. 7.) deinde in trian-gulo ENF duatur IK parallela EF, & æqualis ip&longs;i PB, & ducta RNS parallela ip&longs;is EF, & IK reuolua­tur figura circa axim RS vt fiant duo cylindri concen­trici EFGH, & IKLO; intelligatur modò &longs;patium internum IKLO repletum &longs;ub&longs;tantia homogenea ip­&longs;i cylindro DB, & re&longs;iduum ambiens EFGH explea­tur ex eadem &longs;ub&longs;tantia corporea ip&longs;ius AD; & quia AB ad MB, &longs;iuè cylinder AC ad cylindrum MC, vel cylinder EG ad cylindrum IL triplicatam propor­tionem habet lateris AB ad PB, vel EF ad IK; ergo cylinder AC ad MC eamdem proportionem habet, quam integer cylindrus EG ad cauitatem cylindri­cam IL, & per conuer&longs;ionem rationis cylinder AC ad. cylindrum AD &longs;e habet vt totus cylindrus EG ad partem continentem EKGO. Suntque cylindri AC, & EG æquales, cùm &longs;int &longs;imiles, & &longs;imilitèr po­&longs;iti circa latera æqualia AB, & EF, igitur cylinder excauatus EKGO æqualis e&longs;t &longs;ibi homogenco cylin­dro AD, proindeque cylinder IL æqualis, & homo­geneus erit ip&longs;i MC, quod fuerat.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

His præhabitis noto, quòd cùm agitur de faculta­te, &longs;eù principio quo corpora vim faciunt tendendo deorsùm, qu&ecedil;rimus tantummodò gradum virtutis con­pre&longs;&longs;iuæ eorum, quæ procùl dubio à grauitate, &longs;eu pondere eorum men&longs;uratur, hoc verò duplici modo augeri po&longs;&longs;e con&longs;tat, aut per multiplicationem eiu&longs;­dem corporis, vt cum lignea columna augetur mole, aut cum &longs;ub&longs;tantia corporea, & plena in eodem &longs;patio di&longs;&longs;eminata, & contenta magis &longs;tringitur, conden-&longs;atur, con&longs;tipaturque, & primum vocatur augmen­tum grauitatis exten&longs;iuum, reliquum verò inten&longs;iuum. Regula verò, qua men&longs;urari pote&longs;t gradus prædictæ grauitatis commodè de&longs;umitur à vi contraria, quæ depre&longs;&longs;ionem eius prohibere pote&longs;t, & hic notandum e&longs;t minimè nos &longs;ollicitos e&longs;&longs;e de velocitate motus, qua deorsùm eadem grauia feruntur, &longs;ed tantummo­dò con&longs;iderare vim, & conatum ponderis eius, qui in libra à vi oppo&longs;iti æquipondij præcisè men&longs;uratur.

Vis compri­mens exten­&longs;iuè augetur multiplicata mole corpo­ris.

Inten&longs;iuè ve­rò con&longs;tip­ta, & condi­&longs;ata mate­ria.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Gradus præ dictæ grau­tatis men&longs;u­ratur à vi com traria, quæ depre&longs;&longs;ionem eius prohi­bere pote&longs;t.

Hic no agi­tur de velo­citate de&longs;cen­&longs;us, &longs;ed de vi com pre&longs;&longs;iua.

SVPPOSITIO IX.

Vis &longs;ursùm impellens qu&ecedil; leuitas voca­tur augeri pote&longs;t exten&longs;i­uè multipli­cato eodem corpore le­ui.

NOn &longs;ecùs quando agitur de vi, & energia, qu&atail; corpora, quæ leuia appellantur &longs;ursùm moue­ri nituntur, quæritur non velocitas, &longs;ed vis, quæ &longs;ursùm impellit, quæ leuitas appellari &longs;olet, & hæc quoque duplici modo augeri pote&longs;t, aut exten&longs;iuè, aut intem &longs;iuè, &longs;cilicèt aut multiplicando molem eiu&longs;dem corporis leuis, vt &longs;phæra aeris palmaris octies maio­rem leuitatem habebit, quam &longs;phæra eiu&longs;dem aeris &longs;emipal­maris, propterea quod vis illa leuitatis tantumdem multiplicatur, quantum ma&longs;&longs;a eius corporea exten­ditur, cùm omnes partes eiu&longs;dem aeris æquè leues &longs;int, & æquè raræ, requiraturque vis contraria pro­hibens illius a&longs;cen&longs;um octiès maior quam in huius aeris minori mole requiratur. Secundo modo auge­

ri pote&longs;t leuitas expandendo, & rarefaciendo &longs;ub&longs;tan-tiam corpoream, & plenam, vt nimirum maius &longs;patium occupet, & in hoc ca&longs;u comparari debent &longs;patia occupata, &longs;iuè moles æquales inter &longs;e, & cum medio fluido in quo leuitant, vt &longs;i fuerint duæ pilæ æquales, vna aquea, altera aerea intra mercurium de­mer&longs;&ecedil;, dicetur maior leuitas inten&longs;iuè aeris re&longs;pectu leuitatis aquæ, & leuitates eamdem proportionem habebunt, quàm raritates molium æquallum aeris, & aqu&ecedil; in mercurio con&longs;ideratæ habent. Et hoc eui­dentia &longs;en&longs;us &longs;uadet, &longs;i enim intra hydrargyrum de­mergatur ampulla vitrea plumbo repleta, huius qui­dem gradus leuitatis men&longs;uratur à vi conntraria, quæ a&longs;cen&longs;um eius in mercurio prohibere pote&longs;t, &longs;itque talis vis contraria pondus duarum vnciarum &longs;uper­po&longs;itum, & intra mercutium fixè detinens natantem ampullam. Si po&longs;tea plumbi vncia è cauitate ampul­læ &longs;ubtrahatur, patet quod tantum præcisè totius am­pullæ raritas aucta erit, quantum diminuta fuit &longs;ub­&longs;tantia corporea pondero&longs;a intra ampullam eiu&longs;dem molis, & figuræ contenta, & tunc gradus leuitatis præcisè augebitur vna vncia, nam &longs;i velimus a&longs;censum eiu&longs;dem ampullæ prohibere &longs;uperponi debent non duæ vt priùs, &longs;ed tres vnciæ, po&longs;tea &longs;i ampullæ rari­tas denuò augeatur detracta altera plumbi vncia, gra­dus quoque leuitatis eadem men&longs;ura cre&longs;cet vt ni­mirùm requirantur quatuor vnciæ ad prohibendum eius a&longs;cen&longs;um è mercurio, idemque verificatur &longs;i vlterius pondus internum ampullæ diminuatur; qua­re incrementa leuitatis proportionalia &longs;unt incre-mentis raritatis eiu&longs;dem corporis.

Inten&longs;iuè verò rarefa­ciendo id in corpus.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Incremeleu tatum pro­portionalia sunt incremen­tis raritatum eiu&longs;dem cor­poris eius­denque molis, & mensuran­tur à vi ponde rum prohi­bntium eleua­tiones.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Hinc inferri licet, quòd &longs;i raritas non e&longs;t cau&longs;a ef­fectiua, motus &longs;ursùm, &longs;eù leuitatis, requiritur &longs;altem raritas tamquam affectio nece&longs;&longs;aria, &longs;ine qua leuitas minimè augeri pote&longs;t, &longs;ed oportet vt raritates in ali­quo medio fluido con&longs;iderentur, non autem ab&longs;olu­tè, & in vacuo.

Si raritas non e&longs;t causa a&longs;­cen&longs;us leuium, requiritur tamen nece&longs;­&longs;eriò

PROP. XCIII.

Reperire modò po&longs;&longs;umus corpus, quod in dato fluido a&longs;cendat tanta vi &longs;ursùm, quæ &longs;uperet quamcumque finitam vim.

SIt vas ABC repleaturque flui­

do M quod &longs;it aqua, vel hy­drargyrum, & &longs;it quælibet va­&longs;ta vis motiua R. debet reperiri corpus, quod in prædicto fluido innatet, atque ab eius fundo &longs;ur­sum a&longs;cendat tanta vi, & energia vt &longs;uperet vim datam R. &longs;uma­tur cylindrus DE cuiu&longs;cumque &longs;olidæ materiei con&longs;i&longs;tenti&longs;que, earum tamen, quæ in prædicto fluido M innatant, et vis qua corpus DE a&longs;cendit è fundo fluidi M &longs;it S: po&longs;tea (ex duabus præcedentibus propo&longs;itionibus) reperiatur cylindrus excauatus FG, cuius extern&atail; figura &longs;it æqualis, & &longs;imilis ip&longs;i DE, itaut raritas ab­&longs;oluta ip&longs;ius FG ad raritatem alterius DE maiorem pro-portionem habeat, quam R ad S, & quia (ex 9. &longs;uppo&longs;i­tione) impetus, & energia, qua cylindrus FG &longs;ur­sùm fertur in dato fluido M ad eam vim, qua cylin­drus DE priori æqualis &longs;ursùm fertur in eodem flui­do eamdem proportionem habet, quam raritas cor­poris FG ad raritatem alterius DE, habentque præ­dictæ raritates ne dum ab&longs;olutè, &longs;ed etiam in medio fluido mercuriali con&longs;ideratæ, maiorem proportio­nem, quam R ad S, igitur vis, & robur, quo cylindrus FG &longs;ursùm a&longs;cendit in fluido M ad eam vim, qua ele­uatur ibidem cylindrus DE maiorem proportionem habebit, quam R ad S, erat verò S vis, qua &longs;olidum DE &longs;ursùm transfere batur in fluido M, ergò validi­tas, & energia, qua a&longs;cendit cylindrus FG in eodem fluido maior erit, quàm R, & hoc propo&longs;itum fuerat.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Sed po&longs;&longs;umus faciliùs, & breuiori apparatu pro­blema ab&longs;oluere, &longs;i modò moles corporis innatantis intra aliud fluidum &longs;impliciter augeatur multiplice­turque.

SVPPOSITIO X.

VT præcedens problema faciliùs effici po&longs;&longs;it, priùs præmitti debet, quòd quando agitur de vi, & energia leuitatis, &longs;en&longs;u con&longs;tat duas æquales moles e­iu&longs;dem corporis homogenei v.g. eiu&longs;dem ligni æquè leues e&longs;&longs;e, &longs;cilicèt exercere conatus impul&longs;iuos &longs;ursum inter &longs;e æquales in eodem fluido, in aqua nempè, ita­utimpelli deorsùm debeant ab æqualibus ponderi­bus ad hoc vt vetentur eorum a&longs;cen&longs;us, & fixè infra &longs;upremam aquæ libellam detineantur. paritèr certum e&longs;t inæquales moles eiu&longs;dem ligni inæquales vires leuitatum in aqua habere, & inæqualibus conatibus, & viribus &longs;ursùm impellere; nam &longs;i ex ligno maiori &longs;ecetur auferaturque vna pars æqualis moliligni mi­noris, hæ cùm &longs;int æquè leues, mole&longs;que æquales ha­beant, vt nimirùm prohiberi eorum a&longs;cen&longs;us no&ntail; po&longs;&longs;int, ni&longs;i ab æqualibus ponderibus incumbentibus, videtur impo&longs;&longs;ibile vt exce&longs;&longs;us ille ligni maioris &longs;u­pra minorem (cùm &longs;it eiu&longs;dem naturæ ligneæ proin­de que leuis) vim &longs;ursùm non exerceat pro men&longs;ura &longs;uæ quantitaris, & proinde requiratvim contrariam alicuius ponderis incumbentis, vt eius a&longs;cen &longs;us pro­hibeatur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XCIV.

Hoc &longs;uppo&longs;ito demon&longs;trabo, quòd duæ moles eiu&longs;dem leuis corporis &longs;ursùm impellendo in eodem fluido exercent vires, quæ eamdem proportionem habent, quam moles ip&longs;æ.

IN va&longs;e FDE aqua pleno, vel alio

fluido demergantur duæ inæqua­les moles eiu&longs;demligni, quæ &longs;cilicèt æquè rar&ecedil; &longs;int &longs;pecie, vt &longs;unt ABC, & HIK, &longs;it que S leuitas, &longs;eù vis qua li­gnum ABC &longs;ursum a&longs;cendit; atque R &longs;it leuitas alterius HIK. Dico quòd leuitas S ad R eamdem proportionem habet, quam lignea moles ABC ad molem HIK. po­natur leuitas, aut vis eleuans N, quæ habeat ad R quan­libet proportionem commen&longs;urabilem ex in&longs;initis, quæ proponi po&longs;&longs;unt pariterque fiat moles BM ex eodem ligno con&longs;tans quæ ad HIK &longs;e habeat vt N ad R. mani fe&longs;tum e&longs;t, quòd quotie&longs;cumque lignum BM æquatur ligno ABC, runc paritèr vis leuitatis N æqualis erit ip&longs;i S (eò quòd moles æquales eiu&longs;de&mtail; ligni &longs;ursùm æquali vi leuitatis impellunt) & quo­tie&longs;cunque ligni moles BM maior fuerit, quàm ABC &longs;emper leuitas N maior eritleuitate S, & quando li­gnum BM minus fuerit, quàm ABC, erit quoque le­uitas N minor, quàm S, & habent BM, HIK, & N & R quamcumque proportion alitatem commen&longs;urabi­lem, igitur (ex no&longs;tro Euclide re&longs;tituto) moles li­gnea ABC ad molem HIK eamdem proportione&mtail; habebit quam vis leuitatis S, qua nimirùm ABC in aqua a&longs;cendit, ad leuitatem R qua corpus HIK ele­uatur in eodem fluido, quòd fuerat &c.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Lib. 3 prop. 24.

Si quis fortè &longs;u&longs;picaretur ex figurarum diuer&longs;itate prædictorum corporum leuium licèt eiu&longs;dem con&longs;i­&longs;tentiæ homogeneæ &longs;int, & eumdem gradum rarita­tis habeant, alterari po&longs;&longs;eiam dictam proportionali­tatem, monendus profectò e&longs;t, quod præter Ari&longs;tote­lis a&longs;&longs;ertum, vbiait, quod figuræ non &longs;unt cau&longs;æ &longs;implici­tèr a&longs;cen&longs;us, vel de&longs;cen&longs;us corporum in fluido, &longs;ed tantum­modò tardioris, vel celerioris motus, idip&longs;um po&longs;tea de­mon&longs;tratum fuit ex Mechanicis principijs à Ghetal­do, & Galilæo. attamen inca&longs;u no&longs;tro non requirun-tur figuræ corporum a&longs;cendentium omninò diuer­&longs;æ, & di&longs;&longs;imiles inter &longs;e, quia æquè benè no&longs;træ de­mon&longs;trationi aptari po&longs;&longs;unt cylindri æquè alti, & in­æqualium ba&longs;ium, &longs;iuè contra &longs;i ba&longs;es æquales &longs;int, altitudines &longs;int inæquales. hoc præmi&longs;&longs;o libet idipsum problema alia ratione re&longs;oluere.

Diner&longs;itas figuratum non alterat præ­dictam pro­portionali­tatem.

4. de Cælo. cap. 6.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XCV.

Dato quocumque fluido, in quo corpus aliquod &longs;olidum inna­tare valeat, reperiri debet moles quam habere debet, vt in eadem fluido a&longs;cendere pos&longs;it tanta vi, vt &longs;uperet quamcumque finitam virtutem motiuam.

SIt vas FDE, impleaturqu&etail;

fluido M, aqua nimirùm, aut quolibet alio con&longs;i&longs;tenti fluido. Sumatur po&longs;tea ligneus cylinder ABC, vel quælibet alia materia, quæ in pr&ecedil;dicto fluido innatet, &longs;it­que quælibet immen&longs;a, &longs;ed tamen finita vis R, debet reperiri mo­les, & amplitudo quam haber&etail; debet corpus aliud homogeneum ip&longs;i ABC, vt tanta vi in fluido M a&longs;cendat quæ maior &longs;it virtute motiua R. Immergatur in eodem fluido cylindrus ABC, eiu&longs;que leuitas in fluido, &longs;eu vis, qua nititur in eo a&longs;cendere &longs;it S. Po&longs;teà fiat cylindrus HIK &longs;imilis homogeneus, & eiu&longs;dem materiæ ac e&longs;t ABC, & tantæ va&longs;titatis, vt ad eum moles ABC minorem proportionem habeat, quam S ad R, &longs;cilicèt &longs;it vt S ad V, quæ maior erit quam R, & quia eiu&longs;dem &longs;ub­&longs;tantiæ nempè ligni factæ &longs;unt duæ moles ABC, & HIK; igitur (ex præcedenti) vt cylindrus ABC ad HIK, ita &longs;e habet ab&longs;oluta leuitas illius S ad huius le­uitatem, quæ erit V, & habet S ad R maiorem propor­tionem, quàm moles ABC ad HIK, igitur leuitas V, &longs;eù vis, qua &longs;olidum HIK a&longs;cendit in flui do M maior e&longs;t quacumque data vi finita R.

Cap. 4. po&longs;i­tiuam leui­tatem non dari.

PROP. XCVI.

Idip&longs;um problema effici po&longs;&longs;e methodo Archimedæa &longs;ic ostendemus.

SVmatur lignum L, vel aliud

corpus &longs;ibi homogeneum, quod innatare po&longs;&longs;it intra flui­dum M, ponaturque quælibet vis finita ponderis P, atque vt pondus ab&longs;olutum molis fluidi M, quæ æqualis &longs;it ip&longs;i L, ad pondus ab&longs;olutum ligni L, &longs;ci­licèt vt grauitas &longs;pecifica flui­di M ad L, it a &longs;e habeat R ad S, po&longs;tea fiat cylindr us ACB eiu&longs;dem materiei L, ad cuius grauitatem ab&longs;ol utam pondus P minorem proportio­nem habeat, quàm differentia ip&longs;arum R, & S ad S. Tandem immergatur cylindrus AC intra fluidum M contentum in va&longs;e FDE tantæ profunditatis, vt cy­lindrus AC vniuersè, & perpendicularitèr ad Hori­zontem mergi po&longs;&longs;it, vt eius ba&longs;is non contingat fun­dum va&longs;is FDE, atque &longs;upremus terminus C fluidi li­bellam contingat. Præterea applicari debet pondus P &longs;upra verticem cylindri CA, itaut pondus P immi­neat &longs;upra fluidi libellam, neque aliqua eius portio
demergatur. His præparatis quia exce&longs;&longs;us ponderis R &longs;upra S ad ip&longs;um pondus S maiorem proportionem habet quam gra­uitas P ad pondus cylindri ACB, ergò componendo, gra­uitas R ad S maiorem proportio nem habebit quàm duo ponde­ra P, & CAB, &longs;imul &longs;umpta, ad pondus CAB; verùm grauitas molis fluidi M æqualis &longs;olido AC ad pondus ab&longs;olu­tum eiu&longs;dem &longs;olidi AC habet eamdem proportionem, quam R ad S, ergò moles fluidi M æqualis &longs;olido AC ad &longs;olidum idip&longs;um AC, &longs;eù illius pondus ad graui­tatemhuius habebit maiorem proportionem quàm pondera P, & CAB &longs;imùl &longs;umpta ad pondus AC, & proindè pondus ab&longs;olutum molis fluidi M æqualis AC maius erit grauitate ip&longs;ius P vnà cum ponder&etail; cylindri AC. Verumtamen Archimedes demon&longs;tra­uit &longs;olidum innatans tunc &longs;olummodò in fluido quie­&longs;cere quando eius pondus ab&longs;olutum æquale fuerit grauitati molis fluidi ambientis, quæ &longs;it æqualis por-tioni eiu&longs;dem &longs;olidi intra eiu&longs;dem fluidi libellam de­mer&longs;i. Qua proptèr quando pondus ab&longs;olutum præ­dicti &longs;olidi minus fuerit pondere prædicti fluidi am­bientis æqualis portioni eius demer&longs;æ nece&longs;&longs;ariò &longs;olidum ip&longs;um in fluido eleuabitur vlteriu&longs;que a&longs;cen­det, igitur Cylindrus AC vnà cum &longs;uperincumben­te pondere P eique coniuncto, & continuato no&ntail; quie&longs;cet, &longs;ed &longs;ursùm a&longs;cendet, quaproptèr vis pre­mens ponderis P non &longs;ufficit, nec habet tanta&mtail; vim vt retineat &longs;olidum AC integrè infra fluidi M libellam demer&longs;um. Cùmque, vt Archimedes de­mon&longs;trauit, energia, & vis, qua &longs;olidum AC cona­tur, & vim facit vt &longs;ursùm a&longs;cendat in fluido M &ecedil;qua­lis &longs;it vi illius ponderis, quod &longs;i &longs;uper id imponatur, pote&longs;t id retinere infra fluidi libellam prohibereque cius a&longs;cen&longs;um, igitur vis, qua cylindrus AC conatur &longs;ursùm a&longs;cendere in fluido M maior e&longs;t quacumque vi finita ponderis P, & hoc propo&longs;itum fuerat.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

De in&longs;ident. umido lib. 1. prop. 4.

Cap. 4. po&longs;i­tiuam leui­tatem non dari.

Eod. lib. 1. prop. 6.

PROP. XCVII.

His præmis&longs;is deucnio iam ad propo&longs;itionem principalem, quòd nimirùm quodlibet corpus &longs;ursùm a&longs;cendens in date aliquo fluido non eleuatur &longs;ponte &longs;ua à principio nempè intrin&longs;ecoleuitatis impul&longs;um.

SIt L quodlibet corpus eorum, quæ à Peripateti­cis vocantur à prædominio aerea, vt &longs;unt ferè omnia ligna, & alia innumera, & fluidum M in va&longs;e FDI contentum, &longs;it que prædictum fluidum, aut aqua, aut hydrargyrum; procùl dubio corpus L intra flui­dum M demer&longs;um &longs;ursùm a&longs;cendet. Demon&longs;trandum modò e&longs;t idip&longs;um non &longs;pontaneo motu ab intrin&longs;eco principio leuitatis a&longs;cendere. Si hoc enim veru&mtail;

non e&longs;t, &longs;it, &longs;i fieri pote&longs;t leuitas corporis L naturalis cau&longs;a, & virtus à qua &longs;pontaneo motu &longs;ursùm impellatur in fluido M. Et primò pr&ecedil;paretur infima ba­&longs;is AB cylindri homogenei ip&longs;i L, vt nimirùm ei vniatur ferru­mineturque lamina aliqua vi­trea, vel metallica, quæ &longs;it op­timè explanata, & læuigata, & eiu&longs;dem materiæ, at­que figuræ, & læuitatis &longs;it pauimentum, vel fundum putei DE. Secundo loco reperta iam &longs;it men&longs;ura cer­ta, & determinata illius virtutis, quæ requiritur ad &longs;eparandam, & diuellendam &longs;uperficiem vitri AB ab immediato contactu cum fundo putei DE, &longs;iuè vis illa, quæ &longs;uperare valet re&longs;i&longs;tentiam prædictaru&mtail; &longs;uperficierum &longs;e tangentium ad vacuum admitten­dum; &longs;upponamu&longs;que huiu&longs;modivim e&longs;&longs;e æquale&mtail; ponderi G, atque reperiatur cylindrus AC eiu&longs;dem materiei L itaut vis leuitatis qua conatur &longs;ursùm mo­ueri in fluido M vna cum vitrea lamina AB maior &longs;it vi, & energia ponderis G, &longs;itque vis illa leuitatis æ­qualis potenti&ecedil; H. quapropter vis qua &longs;olidum AC conatur, & impetum facit vt &longs;ursùm in dato fluido a&longs;cendat, maior e&longs;t illa vi, & facultate, quæ requi-ritur ad &longs;eparandam, & diuellendam ba&longs;im AB à fun­do putei DE horizonti æquidi&longs;tante. dum igitur ba­&longs;is AB immediatè, & exqui&longs;itè tangit fundum putei DE, vt &longs;ibi mutuò congruant, exo&longs;culenturque, re­pleatur vniuer&longs;um vas FE prædicto fluido M quou&longs;­que &longs;uprema fluidi libella ad &longs;ummitatem C cylindri AC demer&longs;i pertingat. Et quia hìc iam exi&longs;tunt, & operantur duæ vires contrariæ, vna quidem H im­pellit &longs;ursùm, e&longs;tque virtus eius leuitatis, alia verò G, quæ huic re&longs;i&longs;tit, & vim deorsùm tendendo facit, e&longs;tque energia contactus &longs;uperficierum AB & DE, &longs;eù repugnantia ad vacuum admittendum qua con­trario ni&longs;ui a&longs;cen&longs;us cylindri AC re&longs;i&longs;tit: E&longs;tque con­traria vis H leuitatis, prædicti cylindri maior virtu­te G tenacitatis, vel repugnantiæ ad vacuum, quæ impetum contrarium deorsùm facit; igitur maior vis leuitatis H nece&longs;&longs;ariò &longs;uperare debet vim minorem G, & proinde di&longs;trahet diuelletque cylindrum AC à fundo putei DE, atque po&longs;t &longs;eparationem idip&longs;u&mtail; &longs;ursùm ad &longs;uperficiem fluidi M impellet, transferet­que; &longs;ed hoc e&longs;t fal&longs;um, & contra &longs;en&longs;us euidentiam, proptereà quòd numquam contingit vt ba&longs;is colum­næ AB &longs;eparetur à contactu fundi putei DE, licèt &longs;up­ponatur vim leuitatis quocumque exce&longs;&longs;u vim con­tactus &longs;uperare, igitur verum non e&longs;t cylindrum AC &longs;ursùm impelli ab intrin&longs;eca, & po&longs;itiua facultat&etail; leuitatis eius, quod fuerat demon&longs;trandum.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Prop. 88. & 89.

Pro. 93. 95. & 96.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

PROP. XCVIII.

Confirmatur eadem præcedens propo&longs;itio.

ET procùl dubio cen&longs;eri non debet vera cau&longs;&atail; alicuius effectus illa qua po&longs;ita, & non impe­dita ab excedente vi contraria, non ponitur nihilo­minùs, nec &longs;ub&longs;equitur effectus, &longs;ed po&longs;ita leuitat&etail; po&longs;itiua in prædicta lignea columna AC infra fluidum M demer&longs;a, & non impedita à virtute contraria con­tactus, aut à timore vacui (eò quòd ex con&longs;tructio­ne hæc multò minor fuerat virtute, & energia leui­tatis) non &longs;ub&longs;equitur nihilominùs effectus a&longs;cen&longs;us columnæ in prædicto fluido, igitur leuitas po&longs;itiu&atail; non e&longs;t cau&longs;a a&longs;cen&longs;us &longs;ursum prædicti ligni in fluido M.

Po&longs;tquam o&longs;ten&longs;a fuit pr&ecedil;dicta negatiua propo&longs;i­tio.

PROP. XCIX.

Demon&longs;trabitur iam quod nece&longs;&longs;ariò admitti debet cum Pla­tone, & Archimede, quòd corporaomnia, quæ leuia appellantur &longs;ursùm a&longs;cendunt ab extru&longs;ione fluidorum in quibus innatant ob exce&longs;&longs;um grauitatis eorumdem.

QVia illa e&longs;t vera cau&longs;a alicuius effectus natura­lis, qua|po&longs;ita &longs;ub&longs;equitur effectus, & ablata pariter effectus tollitur, &longs;ed po&longs;ita extru&longs;ione facta à corpore fluido grauiori &longs;ub&longs;equitur effectus a&longs;cen-&longs;us nimirùm &longs;olidi minùs grauis in eo demer&longs;i, & quotie&longs;cumque prædicta extru&longs;io tollitur, aut im­peditur, aufertur quoque vetaturque a&longs;cen&longs;us præ­dicti corporis &longs;olidi, igitur nece&longs;&longs;ariò prædicta ex­tru&longs;io grauioris fluidi ambientis e&longs;t vera, & legitima cau&longs;a a&longs;cen&longs;us eorum corporum, quæ leuia appellan­tur; &longs;ic quia in hypothe&longs;i in propo&longs;itione 97 expo&longs;i­ta extru&longs;io aquæ, vel hydrargyri tollitur, & impedi­

tur, cùm fluidum M interlabi, aut excurrere non po&longs;&longs;it infra ba&longs;im AB prædictæ column&ecedil; ob arctam connexionem contactus ba&longs;is AB cum fundo putei DE, licèt ambiens fluidum multò gra­uius &longs;it prædicta colunna lignea, & in tali ca&longs;u columna &longs;ursùm in fluido non a&longs;cendit. E contrà quotie&longs;cumque extru&longs;io fieri pote&longs;t, &longs;cilicèt quoties fluidum M excurrere pote&longs;t infra ba&longs;im AB ob con­cu&longs;&longs;ionem, vel minimam dilatationem &longs;uperficierum &longs;e tangentium, &longs;eù ob tran&longs;itum per fi&longs;&longs;uram, aut fo­ramen aliquod collaterale, tunc &longs;ub&longs;equitur effectus a&longs;cen&longs;us prædictæ columnæ, igitur nece&longs;&longs;ariò extru­&longs;io facta à grauiori fluido M e&longs;t vera cau&longs;a &longs;ublima­tionis, & a&longs;cen&longs;us prædictiligni in fluido, quod fue­rat o&longs;tendendum.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Et hìc &longs;ummopere animaduertendum e&longs;t, hallucina­tionem pendere ex eo quòd tribuitur effectus no&ntail; veræ cau&longs;æ, &longs;ed alij imaginatæ, quoniam quotie&longs;cun-que lignum &longs;ursùm a&longs;cendit in aqua &longs;emper verifi­catur id minùs grauitare, quàm moles aquæ ambien­tis ei æqualis, quæ &longs;i liberè fluere, & excurrere po­te&longs;t infra eius ba&longs;im, &longs;cilicèt &longs;i exercere pote&longs;t ex­ce&longs;&longs;um &longs;ui ponderis, mirum non e&longs;t eleuare corpus minoris grauitatis, &longs;icuti in libra videmus minus pon­dus à maiori &longs;ubleuari, quotie&longs;cumque tamen pon­dus maius liberè vim &longs;uam exercere pote&longs;t, at &longs;i fue­rit &longs;ub&longs;tentatum, vel fulciatur à pauimento pondus minus eleuare non poterit. Huiu&longs;modi cau&longs;a, quæ certa e&longs;t, & nece&longs;&longs;ariò operari debet iuxtà leges me­chanices, numquam pote&longs;t, nec debet excludi, vt ac­ceptetur imaginata cau&longs;a leuitatis po&longs;itiuæ, quæ &longs;i ade&longs;&longs;et, &longs;uum effectum producere deberet in ca&longs;u pro­po&longs;itionis 97. vbi nil prorsùs operari o&longs;ten&longs;um e&longs;t, tamquàm &longs;cilicèt &longs;i non e&longs;&longs;et.

Cau&longs;a hacination de tegitur.

Cap. 4. po&longs;i­tiuam leui­tatem no&ntail; dari.

Po&longs;tquam igitur examinauimus, & reiecimus ra­tiones omnes Peripateticas contra Platonem, & alios antiquos pro a&longs;&longs;ertione leuitatis po&longs;itiuæ, pariter­que inefficaces repertæ &longs;unt omnes aliæ rationes, quæ pro confirmatione prædictæ &longs;ententiæ circumfe­runtur, cùmque tandem methodo demon&longs;tratiua ve­ritatem no&longs;træ &longs;ententiæ confirmauerimus, po&longs;&longs;umus iam, ab&longs;que iactantia, affirmare euici&longs;&longs;e nullam leuitatem po&longs;itiuam in natura dari virtute cuius naturalia cor­pora conentur di&longs;cedere à no&longs;tra terra versùs &longs;upe­riores partes, &longs;ed è contra pronunciare po&longs;&longs;umus re­periri in omnibus corporibus &longs;ublunaribus vim quan­dam vniuer&longs;alem &longs;e mutuò complectendi, & globo terreno adhærendi mediante facultate de&longs;cen&longs;iu&atail;, quæ grauitas appellatur, hæc, inquam, grauitas di­uer&longs;imodè participata à corporibus terram ambien­tibus efficit vt minùs grauia expul&longs;a ex inferioribus locis à grauioribus illa &longs;ursùm eleuentur, & &longs;ic cor­pora elementaria optima quidem con&longs;titutione æqui­librentur, & ad &longs;ua loca naturalia ad&longs;portentur vt ibi­dem quie&longs;cant.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

De Structura, Grauitate, Æquilibrio, & Vi Elateria Aeris.

CAP. V.

IAm &longs;uperiùs &longs;atis &longs;uperque o&longs;ten&longs;um e&longs;t aqua&mtail; grauitare etiam in propria regione, & in &longs;uo toto: præterea o&longs;tendimus nullam leuitatem po&longs;itiuam re­periri in corporibus mixtis, in ijs nempè, quæ à præ­dominio aerea vulgò appellantur, quod verò peculi­ariter aer grauis &longs;it, ne dum Ari&longs;tot. apertè fatetur, cùm ait: Omnia elementa grauitatem habere prætèr ignem, pariterquè omnia leuitatem habere prætèr terram. Hinc in­fert: terram igitur, & quæ terræ habent plurimum, vbique grauitatem habere e&longs;t nece&longs;&longs;arium. Aquam autem vbique, prætèr quàm in terra, aerem verò præterquam in aqua, & terra. In &longs;ua enim regione omnia grauitatem habent prætèr ignem, etiam aer ip&longs;e. Signum autem est quia trahit plùs in­flatus vter, quàm vacaus. Sed etiam demon&longs;trari po­te&longs;t eodem modo, ij&longs;demque rationibus, quas in pr&ecedil;­cedenti capitulo adduximus, &longs;icuti enim ibi con&longs;ide-rauimus ligna, ampullas vitreas|, & ve&longs;icas aere ple­nas per aquam a&longs;cendentes, demon&longs;trauimu&longs;que eas non vi leuitatis, &longs;ed ab extru&longs;ione medij fluidi &longs;ursùm impelli, &longs;ic pariter &longs;i loco ligni, aut ve&longs;ic&ecedil; ponatur aer in fundo hydrargyri, vel aquæ, olei, vel &longs;piritus vini non &longs;ecùs, ac priùs factum e&longs;t, o&longs;tendemus aerem non &longs;pon­te &longs;ua a&longs;cendere à vi leuitatis tran&longs;latum, &longs;ed à pre&longs;­&longs;ione grauioris medij fluidi violenter &longs;ursùm impel­lentis. licèt ergo negotium omninò confectum e&longs;&longs;&etail; videatur, vtile tamen erit idip&longs;um confirmare ex æ­quilibrio aeris cum cæteris fluidis.

4. de Cælo cap. 4.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. C.

Ex &longs;u&longs;pen&longs;ione mercurij in in&longs;trumento Torricelliano &longs;uadetur aerem, vt grauem, æquilibrium efficere cum mercurio.

ET hac occa&longs;ione con&longs;iderabimus pulcherrimum profectò experimentum eorum, quæ hoc &longs;eculo adinuenta &longs;unt, hydrargyri nempè eleuatio in fi&longs;tula, quam primus omnium animaduertit docti&longs;&longs;imus Tor­ricellius, e&longs;tque experimentum huiu&longs;modi: Sit fi&longs;tu­la vitrea ABC perforata tantummodò in eius extre­mitate C, in A verò clau&longs;a, hæc verò hydrargyro repleta v&longs;que ad &longs;ummitatem C pulpa indicis &longs;trictè claudatur, inuertaturque contrario &longs;itu, vt nimirùm os eius C inferiùs re&longs;piciat; &longs;itque po&longs;tea præparata &longs;cutella DHE pariter hydrargyro plena demerga­tur infimum orificium C fi&longs;tulæ vnà cum digito occlu-dente infrà &longs;upremam hy­

drargyri libellam DE, tunc &longs;ublato digito mercurius profluet ab orificio C quo­u&longs;que altitudo FB extantis hydrargyri&longs;upra libella&mtail; DE &longs;it pedum duorum, & quadrantis, vel vnius cubi­ti, & quadrantis, nec vlte­rius hydrargyrum graui&longs;&longs;i­mum de&longs;cendit &longs;emperque ad eamdem altitudine&mtail; per&longs;euerat, licèt inclinetur fi&longs;tula, &longs;cilicèt ducta recta FG parallela horizonti sen­per &longs;ummitas hydrargyri ad eamdem horizontalem FG perueniet quomodocumque fi&longs;tula inclinetur. Ip&longs;e Torricellius experimenti inuentor &longs;agaci&longs;&longs;imè cau&longs;am quoque huius effectus indagauit, animaduer­tit enim nos in infima profunditate oceani aerei de­mer&longs;os e&longs;&longs;e, & &longs;icuti maris aqua vndique fundu&mtail; comprimit per lineas horizonti perpendiculares, &longs;eù directas ver&longs;us centrum telluris, &longs;ic quoque in oceano aereo ni&longs;us eius grauitatis exercetur perpendiculari­tèr &longs;upra horizontis planum, vnde concipi debent cy­lindri aerei perpendicularitèr &longs;uperficiem hydrargy­ri DE &longs;upremam comprimentes; quia verò eade&mtail; libella mercurij DE comprimitur quoque in &longs;itu B à &longs;uperficie ba&longs;is B mercurialis cylindri FB efforma­tur veluti libra, vel &longs;ipho, quæ numquam quie&longs;cit, ni-&longs;i æquilibrium momentorum efficiatur, &longs;cilicèt ni&longs;i momentum ponderis cylindri aerei &longs;uperficiem DE comprimentis æquale fuerit momento ponderis cy­lindri mercurialis BF. Huiu&longs;modi &longs;peculatio magno plau&longs;u à viris doctis excepta fuit, alij&longs;que experimen­tis pariter comprobata, quia nimirùm &longs;i loco hydrar­gyri aquam adhibeamus, vel aliud fluidum, tunc aqua pura eleuatur ad altitudinem pedum 32. vel cubito­rum 17. proximè cuius pondus præcisè æquatur gra­uitati prædicti cylindri mercurialis BF vnius cubiti, & quadrantis (&longs;umptis nimirum ba&longs;ibus æqualibus) & &longs;i fuerit oleum altius quàm aqua pura eleuatur, &longs;ed præcisè quantum exigit aquæ grauitas ei æqualis; idemque continget &longs;i fuerit aliquis &longs;piritus, vel qui­libet alius liquor. cùm igitur in hi&longs;ce omnibus fi&longs;tulis eleuentur varij liquores, itaut eorum partes eleuatæ &longs;uper infimam libellam &longs;emper eiu&longs;dem &longs;int grauita­tis, dicendum nece&longs;&longs;ariò e&longs;t ab vnica, & eadem vi compre&longs;&longs;iua eleuari, qu&ecedil; &longs;emper eiu&longs;dem roboris &longs;it: at nulla alia a&longs;&longs;ignari pote&longs;t præter pondus cylindri aerei liquori in &longs;cutella contento incumbentis. igitur pote&longs;t aer incumbens eleuare prædictos liquores, hoc autem minimè effici po&longs;&longs;et ab&longs;que eo quod in aer&etail; æquilibrium efficeretur; &longs;icuti in maris oceano ex eo quod omnes partes aquæ æquali ni&longs;u deor&longs;um ferun­tur, & premunt, fit vt eius &longs;uprema libella &longs;phæricè contornetur, &longs;ic paritèr &longs;uprema aeris &longs;uperficies &longs;phæricè tornata erit, ex eo quod partes eius omnes æquali ni&longs;u deor&longs;um grauitantes æquilibrium efficiunt.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CI.

Idip&longs;um clariùs confirmatur.

QVòd po&longs;tea prædicta mercurij eleuatio in fi &longs;tu­la producatur ab aeris compre&longs;&longs;ione &longs;upr&atail; mercurium in &longs;cutella contentum, confirmatur ali&atail; ratione, fed clariùs adhibito in&longs;trumen­to à me excogitato, quod Academiæ Experimentali Medice&ecedil; communicaui, eiu&longs;que ichon habetur figura 34. libri experimentorum ciu&longs;dem Academiæ, ab&longs;que enim &longs;cutella DE &longs;ufficit vt in­fima pars fi&longs;tulæ BC incuruetur, &longs;ur­&longs;umque inflectatur, tunc quidem reple­ta vt priùs vniuer&longs;a fi&longs;tula mercurio, reuoluatur vt eius pars clau&longs;a A & lon­gitudo fi&longs;tulæ AFB perpendicularitèr ad horizontem emineat, tunc quidem ab orificio aperto G hydrargyru&mtail; profluet, vel intra amplitudinem am­pullæ DG reducetur, quou&longs;que altitu­

do mercurialis cylindri FB &longs;upra libellam BD fuerit v­nius cubiti & quadrantis, & tunc concipi debet cylin­drus aereus DS v&longs;que ad &longs;upremam aeris &longs;uperficiem S exten&longs;us, cuius pondus æquetur grauitati cylindri mercurialis FB. Quod verò à compre&longs;&longs;ione prædicti cylindri aerei DS eleuetur graui&longs;&longs;imum hydrargyrum FB probatur ex eo quod &longs;i augeatur impul&longs;us, & com-pre&longs;&longs;io &longs;upra &longs;uperficiem hydrargyri D altiùs ele­uatur mercurius in fi&longs;tula BFA. &longs;ic &longs;i noua fi&longs;tula, vel in&longs;trumento pneumatico aer in&longs;uffletur, vt compri­mat &longs;uperficiem hydrargyri D eleuatur quoque &longs;u­prema &longs;uperficies F hydrargyri in fi&longs;tula clau&longs;a; & &longs;i è contrà embolo retracto, velùti exugatur aer impe­diatur que compre&longs;&longs;io eius &longs;upra mercurium D &longs;pon­tè labetur mercurius de&longs;cendetque deorsùm versùs B. præterea &longs;i &longs;upra mercurium in D infundatur aqua, quæ propagetur vique ad libellam GI, tunc quidem mercurius quoque eleuatur ab F v&longs;que ad H, & quod mirum e&longs;t, eleuatur mercurius præcisè pro men&longs;ura ponderis aquæ incumbentis GD, &longs;cilicèt altitudo G D erit quatuordeciès maior, quàm FH, quia talis re­ciprocè e&longs;t proportio ponderis mercurij ad aquam. Si igitur in &longs;patio inani nulla alia cau&longs;a vlterioris ele­uationis hydrargyri FH a&longs;&longs;ignari pote&longs;t præter gra­uitatem aquæ collateralis GD cum qua mercurius F H æquilibrium efficit, quare negabimus reliquum mercurij FB eleuari à pondere aliquo premente &longs;u­perficiem D, quæ &longs;it &longs;emper eiu&longs;dem roboris? cùm­que nullum aliud corpus grauitans a&longs;&longs;ignari po&longs;&longs;it prætèr aerem, igitur nece&longs;&longs;ariò ab hoc mercurius eleuatur.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Prætermi&longs;&longs;is alijs experimentis excogitatis à viris docti&longs;&longs;imis in Italia, Gallia, & Anglia, de quibus fusè agitur in libro ex perimentorum no&longs;træ Academiæ ex­perimentalis Mediceæ nè repetamus ea, quæ iam pa&longs;­&longs;im vulgata &longs;unt, tantummodò recen&longs;ebo, & ad exa-men reuocabo difficultates contra ratiocinium Torri­cellianum, & no&longs;trum à docti&longs;&longs;imo viro allatas cum ait. Dicebatur &longs;egmentum mercurij IC &longs;ustineri à cylindro aeris eiu&longs;dem ba&longs;is, itaut perfectum &longs;it vtrinque æquilibrium. Contra hanc &longs;ententiam nonnulla militant &longs;i appendatur fi­stula BD po&longs;tquàm &longs;ubducto digito de&longs;cendit mercurius in IC &longs;tatera fideli adhibita, & &longs;ignetur pon­deris ratio, ac deindè citr à mercurij de&longs;cen­&longs;um eadem fi&longs;tula cum æquali quantitate mercurij appendatur, eadem ratio ponderis inuenietur paulò maior, æqualem quantita­tem mercurij intelligo &longs;egmento IC; Et pau­lò infra &longs;ub&longs;equitur. Si mercurius IC &longs;u&longs;tinetur à cylindro exterioris aeris, igitur cum illo perfectum æquilibrium facit, igitur cum alio æquali pondere ad libram appen&longs;o

aliud æquilibrium facere non potest. Supponemus enim mer­curium IC eße trium librarum, æquilibrium facit cum cy­lindro aeris etiam trium librarum. Si autem aliud pondus trium librarum in alter a lance appendatur cum hoc mercuri­us æquilibrium facere nequit, alioquin &longs;ex Libris mercurius æquilibraret, quod legibus staticæ repugnat.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Defficulta­tes contra no&longs;tram do­ctrinam.

PROP. CII.

Euidenti&longs;simo exemplo in aqua o&longs;tenditur quod licèt mercu­rius in fl&longs;tula ab æquipondio aquæ &longs;u&longs;tineatur, nihilo­minùs vis eleuans fi&longs;tulam &longs;ustinet præterea aquæ incumbentis pondus æquale mercurio.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

QVia verò ratiocinium hoc à viro docti&longs;&longs;imo af­fertur vt conuincens, & euidens, conabor, amo­re veritatis, luculentèr exponere eius defectum, & claritatis gratia operationem euidentiorem in ip&longs;&atail; aqua con&longs;iderabo &longs;imilem omninò ei quam præ ma­nibus habemus. Sit vas profundi&longs;&longs;imum RTVS aere plenum in cuius fundo pona­tur &longs;cutella DF mercurio ple­na, &longs;itque po&longs;tea fi&longs;tula vitrea AC vtrinque perforata, & per­uia cuius in fima pars C demer­gatur infra mercurij libellam; po&longs;tea repleatur puteus aqua vt vitri &longs;ummitatem A non at­tingat, & remaneat fi&longs;tula exi­nanita vt prius tunc quidem &longs;en&longs;u con&longs;tat eleuari hydrar­gyrum in fi&longs;tula à C v&longs;que ad

B quou&longs;que mercurialis altitudo CB decima quarta pars &longs;it aquæ altitudinis HG. hic iam quia effectus eleuationis mercurij v&longs;que ad B productus fuit ab a­qua de nouo impo&longs;ita dubitandum non e&longs;t ab eius gra­uitate mercurium eleuatum fui&longs;&longs;e, quod præterea confirmatur ex æquipondio ip&longs;ius cylindri aquæ HG cum mercuriali cylindro CB eiu&longs;dem ba&longs;is; itaque in libra CEG, vel in &longs;iphone tunc quie&longs;cunt duo fluida, mercurius nempè & aqua, cùm præcisè efficitur eorum æquilibrium; claudatur po&longs;tea fi&longs;tula in B interpo&longs;ita nimirùm laminula non di&longs;&longs;imili ei, quàm in arundini-

hus ob&longs;eruamus à qua præcisè prohibeatur tran&longs;itus fluidi per rimas laterales, po&longs;tea impleatur reliqua pars fi&longs;tulæ AB aqua, & tandèm eadem vitrea fi&longs;tu­la termino I libræ IL radiorum æqualium &longs;u&longs;penda­tur, atque ab oppo&longs;ito termino eius L pendeat pon­dus M æquale ponderi ip&longs;ius vitri AC. videndu&mtail; modò e&longs;t an à &longs;implici pondere M &longs;u&longs;tineri po&longs;&longs;it vi­trea fi&longs;tula AC, & patet non &longs;ufficere, quia in &longs;ipho­ne ACGH pondus cylindri aquei HG æquatur præ­cisè ponderi mercurij BC, cumque pr&ecedil;terea aqua con­tenta in &longs;patio fi&longs;tulæ AB ferè æqualis &longs;it aquæ HG, ergò &longs;umma aquæ AB, & mercurij BC duplo grauior e&longs;t, quam &longs;it cylindrus aqueus HG vt nimirùm &longs;i a­qua HG fuerit vnius libræ erunt mercurius CB, & aqua AB ferè duarum librarum (non con&longs;iderato pon­dere ip&longs;ius vitri AC,) ergò vt fiat æquilibrium de­bet addi ponderi M aliud pondus O, quod &longs;it æqua­le ponderi aquæ AB, & tunc in infima libra CEG, &longs;eu &longs;iphone e&longs;&longs;icitur æquilibrium inter cylindrum a­queum HG, & mercurium CB, in &longs;uprema verò li­bra IL efficitur æquilibrium inter fi&longs;tulam vitrea&mtail; AC, vnà cum aqua AB ex vna parte, & ponderæ M, O ex altera parte. Igitur quia reuera mercurius CB non &longs;u&longs;tinetur à potentia O &longs;ubleuante libram &longs;upre­mam, cum nimirùm &longs;u&longs;tineatur à collaterali aqua HG, e&longs;t impo&longs;&longs;ibile fi&longs;tulam vitream AC &longs;u&longs;tineri à &longs;o­litario pondere M æquale grauitati ip&longs;ius vitri, ni&longs;i in&longs;uper addatur alia potentia O, quæ &longs;u&longs;tineat cy­lindrum aqueum AB æquè graue ferè, ac|e&longs;t mercu­rius CB.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Si po&longs;tea fi&longs;tula vitrea &longs;ecetur in B, eiu&longs;que &longs;upre­ma portio BA tollatur amoue aturque, at que pondus M æquale &longs;it grauitati vitri decurtati CB, tunc quidem incumbit, ac innititur fi&longs;tul&ecedil; cylindrus aqueus BA fi&longs;tulamque comprimit non &longs;ecus, ac priùs quando intra cauitatem fi&longs;tulæ AB continebatur.

PROP. CIII.

Licèt Torricelliana fistula à mercurio in ea &longs;u&longs;pen&longs;o non gra­uetur, tamen manus cogitur &longs;u&longs;tinere pondus cylin­dri aerei fi&longs;tulæ incumbentis, quod æquatur pon­deriinclu&longs;i mercurij.

IDip&longs;um no&longs;træ fi&longs;tulæ directæ in ae­re con&longs;titutæ adaptari pote&longs;t, &longs;it­que illa AC duorum cubitorum habe­atque orificium C in&longs;ignis exiguitatis, repleaturque mercurio deor&longs;umqu&etail; inuertatur in aere libero (non enim nece&longs;sè e&longs;t, vt os C intra &longs;cutellam mercurij plenam infundatur, quando valdè &longs;trictum e&longs;t os eius C,) tunc ab infimo orificio C mercurius in ae­re profluet quou&longs;que altitudo CB fuerit vnius cubiti, & quadrantis pro­ximè. Hic concipi debet cylindrus aereus SG v&longs;que ad &longs;upremam regio­

nis aeris &longs;uperficiem exten&longs;us, quire­flexus per EC vim faciat contra pre&longs;&longs;ionem mercu­rij BC, eumque &longs;u&longs;pendat, & &longs;ic liberè concedo ad-

uer&longs;ario, quòd fi&longs;tula AC nil prorsùs ab inclu&longs;o mer­curio BC grauatur, & &longs;ic de facto experimur appli­cata digiti pulpa ori infimo fi&longs;tulæ; quod in part&etail; intermedia pulpæ à mercurio tacta nulla compre&longs;&longs;io, nec contu&longs;io neque grauitatio per&longs;entitur, quando præ­cisè mercurij altitudo BC e&longs;t vnius cubiti, & qua­drantis ferè; quod &longs;ieius altitudo &longs;upra CB augeatur, tunc &longs;olummodò percipitur in medio pulpæ digiti &longs;ub­iecti compre&longs;&longs;io grauitans iuxtà men&longs;uram exce&longs;&longs;us mer­curij &longs;upra eum qui altitudinem vnius cubiti, & qua­drantis occupat, & &longs;i è contrà mercurius deprima­tur violentèr infra debitam altitudinem BC, tunc ne­dùm &longs;ubiecta pulpa digiti non comprimitur, &longs;ed è contrà exugitur, vt efficiunt cucurbitæ medicæ, & hyrudines. Sed dicet aduer&longs;arius &longs;i mercurius BC nil grauitat, nec comprimit digitum, quare requi­ritur vis, aut libræ, aut digiti &longs;ubiecti, quæ nedu&mtail; æquet pondus &longs;olias vitri AC, &longs;ed prætereà &longs;u&longs;tine­re valeat duas libras v. g. quas pendit mercurius BC? Re&longs;pondeo aereum cylindrum SA fi&longs;tulæ vitreæ in­cumbentem &longs;ua grauitate agere non minùs, quà&mtail; collateralis cylindrus aereus SG, cumque vitru&mtail; CA non repellatur æquali actione contraria &longs;ursùm ab aere collaterali SG, quia huius vis exercetur, & omninò expletur &longs;u&longs;tentando mercurium BC; igitur nece&longs;&longs;ariò vitrum CA comprimitur deorsùm à gra­uitate aeris incumbentis SA, cuius pondus æqual&etail; e&longs;t mercurio BC hinc fit vi ex præconcepta fal&longs;a opi­nione tribuamus compre&longs;&longs;ionem aeris SA nobis in-compertam alij cau&longs;æ nempe grauitati ip&longs;ius mer­curij BC intra fi&longs;tulam contenti. Hoc profectò con­firmatur ex eo, quod prædicta fi&longs;tula à digito &longs;u&longs;ten­tata exercet &longs;uam compre&longs;&longs;ionem contra pulpæ di­giti extremitatem, quæ à perimetro orificij vitri tan­gitur, & contunditur: non autem contra mediam pul­pæ digiti partem, quæ ab ingenti pondere trium li­brarum mercurij v. g. magis, & euidentius compri­mi deberet quàm grauentur ambientes pulpæ digi­ti partes à perimetro ori&longs;icij vitri trium vnciarum.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Hanc euidenti&longs;&longs;imam demon&longs;trationem conatur aduer&longs;arius refellere, ait enim, hoc facilèreijcitur nem­pè æqualis cylindrus aeris incumbit ba&longs;i &longs;upremæ obstructæ fistulæ &longs;iuemercurio, &longs;iue aqua, &longs;iue aere fi­&longs;tula plena &longs;it, vt patet. Vnde &longs;i quem haberet effectum, eumdem &longs;emper haberet, &longs;ed hæc in&longs;t antia futilis est, quare in ea diutiùs mi­nimè hærendum. Sit fi&longs;tula AC plena ae­re non mercurio &longs;u&longs;tenteturque infer­nè eius orificium C à &longs;ubiecta digiti pulpa, concedo, quod &longs;upernè digi­tus premitur à columna aeris SAC, pa­riterque comprimitur à vitri fi&longs;tula AC, quidnam ex hoc deducit aduer&longs;arius? dicet, quod tantumdem ponderis pa­teretur digitus &longs;ubiectus quando vitrea fi&longs;tula exinanita e&longs;t, quàm &longs;i mercurium

BC contineret, &longs;cilicèt &longs;i fi&longs;tula pen­deret duas vncias, & aereus cylindrus SA pendat tres libras exinanita fi&longs;tula æquè comprimeretur &longs;ubie­ctus digitus à pondere totius cylindri aerei SA trium librarum vnà cum duabus vncijs vitri AC, cùmque hoc &longs;it fal&longs;um; fi&longs;tula enim exinanita duas vncias &longs;o­lummodò pendit, non ergo &longs;uprema colummna aerea SA fi&longs;tulam, & proindè digitum &longs;ubiectum compri­mit.

Conti am &longs;upe­rius expo&longs;itam doctrinam de­nuo aduer­&longs;arius in&longs;ur­g&longs;t,

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CIV.

Fi&longs;tula exinanita, licèt grauetur à cylindro aereo incumben­te non minus, ac quando extante mercurio repletur, debet tamen in primoca&longs;u &longs;ubiectus digitus vi­tri tantum pondus percipere, in &longs;ecundo ve­rò præterea à pondere æquali merourio &longs;u&longs;pen&longs;o grauabitur.

HVic difficultati re&longs;pondetur, quòd, vt multotiès in&longs;inuatum e&longs;t, nulla alia de cau&longs;a fluida cor­pora circa tellurem &longs;phæricè contornantur, ni&longs;i prop­tèr eorum æquilibrium, &longs;cilicet quia omnes eius par­tes æquali ni&longs;u vim faciunt tendendo deorsùm, & po&longs;tquam à &longs;oliditate terræ &longs;ubiectæ eius progre&longs;­&longs;us deorsùm impeditur ni&longs;u reflexo veluti in &longs;iphone vici&longs;&longs;im &longs;e mutuo impellunt quoque partes fluidi, vel &longs;olidi eleuatæ &longs;ursùm, itaque in ca&longs;u no&longs;tro, concipi debet nedùm columna aerea SAC, &longs;ed etiam alia ei æqualis aerea columna SG, quæ infernè per EC re­flectatur, & &longs;ursùm impellat digitum &longs;u&longs;tentantem vitrum æquali ni&longs;u, ac ip&longs;a &longs;upernè comprimitur à cylindro aereo SAC. digitus ergo con­primitur à duabus æqualibus viribus inter &longs;e contrarijs veluti forcipe, de­orsùm quidem à pondere aereo SAC, &longs;ursum verò a vi pre&longs;&longs;ionis aeris SG re­flexi per EC, eodem ferè modo quo vri­natores pondus incumbentis aquæ non percipiunt, quia nimirùm æquali vi &longs;ursùm motu reflexo impelluntur ab a­qua &longs;ubiecta, ac grauantur ab aqu&atail; &longs;uprema de&longs;cendente, vt &longs;uperius o&longs;ten­sum fuit; igitur in ca&longs;u noftro digitus &longs;u­&longs;tinebit tantummodò grauitatem dua­rum vnciarum fi&longs;tulæ vitreæ exinani­

tæ AC quia nimirùm hic e&longs;t exce&longs;&longs;us ponderis totius columnæ aereæ, & vitreæ SAC &longs;upra aeream columnam ei &ecedil;qualem SGC: diuer&longs;i&longs;&longs;imus ergo e&longs;t ca&longs;us fi&longs;tulæ vitreæ mercurio &longs;tagnante repletæ, quia nimirùm vis compre&longs;&longs;iua colunnæ aereæ SG om­ninò expletur ab&longs;umiturque eleuando &longs;u&longs;tinendoque mercurium BC, & &longs;ic remaneat aerea columna SA (prætèr vitrum) non &longs;u&longs;tentata à repul&longs;ione eiu&longs;dem aeris SG, & proindè &longs;u&longs;tineri debèt à digito &longs;ubiecto eo mode, quo &longs;upra expo&longs;uimus.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Quapropter conuincens non e&longs;t argumentum do­cti&longs;&longs;imi viri, ideoque remanent illibatæ rationes &longs;u­periùs adductæ quibus per&longs;uademur mercurium in fi­&longs;tula &longs;u&longs;tineri à pre&longs;&longs;ione circumambientis aeris.

Tran&longs;eamus iam ad examen tertiæ rationis ab eo-dem viro clari&longs;&longs;imo adductæ, inquit enim: Si &longs;egmentum IC mercurij ab ae­ris exterioris cylindro &longs;u&longs;tinetur, igitur cum cylindrus exterior eamdem vim &longs;emper habeat æqualem &longs;egmentum IC &longs;emper &longs;ustinet. Sed hoc experimento repugnat, nam &longs;i tantulum aeris antequàm demit­tatur mercurius in fi&longs;tula relinquatur mer­curius de&longs;cendet infra C; in C autem &longs;u&longs;ti­neri deberet &longs;i à cylindro aeris exterioris &longs;u&longs;tineretur vt patet &c.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Tertium ar­gumen um eiu&longs;dem au­thoris.

Non latuit huius argumenti authorem re&longs;pon&longs;io à fautoribus contrariæ &longs;ententiæ allata, nimirùm illud tantulum aeris infra fi&longs;tulam relicti po&longs;t de&longs;cen&longs;um mer­curij liberiorem nanci&longs;ci campum, ac proindè cum ante com­pre&longs;&longs;us e&longs;&longs;et explicare &longs;e&longs;e, ac dilatare, & premere &longs;uperfi­ciem mercurij, vnde hic infra C de&longs;cendit. Sed in&longs;tat di­cendo; tantam aeris compres&longs;ionem iam &longs;upra &longs;atis effi­cacitèr ab ip&longs;o refutatam fui&longs;&longs;e.

Sed an reuerà iure refutata fuerit, po&longs;teriùs o&longs;ten­demus, modò tantam aeris dilatationem argumento ab eadem experientia deducto retinebimus; attamen interea erit operæpretium exponere quomodò, & quando aer intra mercurium in fi&longs;tula relictus expli­cetur dilateturque.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CV.

Exponitur quare, & quando aer relictus in fi&longs;tula Torri­celliana altitudinem mercurij con&longs;uetam deprimere debeat; & &longs;imul traditur modus men&longs;urandi maximam aeris dilatationem.

EX Roberuallij pulcherrima ob&longs;eruatione illius ve&longs;icæ cyprinæ, quæ in vacuo fi&longs;tulæ dilatatur ego conieci reperiri facilè po&longs;&longs;e in eodem Torricel­liano in&longs;trumento maximam amplitudinem, ad quam aer non compre&longs;&longs;us à vi externa, & in &longs;ua libertat&etail; relictus dilatari queat, quæ dilatatio certum, ac de­terminatum &longs;patium in vacuo Torricelliano occupa­ret, quod nimirum &longs;ufficienter exciperet maximam eiu&longs;dem aeris expan&longs;ionem. Hinc po&longs;tea deducebam molem aeris, quæ præcisè &longs;patium vacuum in Tor­ricelliano in&longs;trumento occuparet (quam molem me­diocrem appellabimus) non po&longs;&longs;e deorsùm impelle­re, & magis comprimere &longs;uperficiem &longs;upremam mer­curij &longs;tagnantis, ac proindè omnes moles aeris mi­nores illa, & ideò minus &longs;patium po&longs;t totalem eo­rum dilatationem exigentes non po&longs;&longs;e prædictam mercurij &longs;upremam &longs;uperficiem deprimere, cum è con­trà moles omnes acris excedentes &longs;upradictam me­diocrem molem, & ideò exigentes amplius &longs;pa­tium deprimere nece&longs;&longs;ariò &longs;upremam mercurij &longs;uper­ficiem in fi&longs;tula infra con&longs;uetam altitudinem vnius cubiti, & quadrantis.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Vtque hæc experientia commodè exequi po&longs;&longs;et efformaui fi&longs;tulas vitreas &longs;extam, & feptimam deli­neatas folio 43. libri experimentorum no&longs;træ Aca­demiæ Experimentalis Mediceæ, &longs;ed po&longs;tea facilio­ri apparatu idip&longs;um con&longs;equi po&longs;&longs;e animaduerti me­diante hoc in&longs;trumento, e&longs;tque eius artificium hu­iu&longs;modi: ampullæ vitreæ AB cuius diameter proximè quatuor digitos adæquet continuetur prælonga fi&longs;tu­la BC maiore duorum cubitorum, quæ in&longs;lexa &longs;it i&ntail; eius infimo loco CEF, atque in &longs;upremo loco eius A continuetur quoque &longs;tricta alia fi&longs;tula AD cuius ex­tremum &longs;upremum orificium apertum D claudi po&longs;­&longs;it po&longs;t mercurij infu&longs;ionem &longs;uilla ve&longs;ica; po&longs;tea ter­minus extremus alterius fi&longs;tulæ FG vniatur cum al­tero extremo fi&longs;tulæ incuruatæ appo&longs;itis colligati&longs;­que portionibus inte&longs;tini agnini, quæ ne rumpantur diffringantur que à nimio mercurij pondere pariter operiantur fi&longs;tula, vel digitali coriaceo, atque arctè alligatis inte&longs;tinis, & corio vtri&longs;que extremitatibus fi&longs;tularum, poterit facilè fi&longs;tula FG inflecti &longs;ursùm, & deorsùm po&longs;t mercurij infu&longs;ionem, eriganturqu&etail; perpendiculariter ad horizontem ambæ fi&longs;tulæ DB C, & GF. His præparatis per orificium D infundatur hydrargyrum quou&longs;que duæ fi&longs;tulæ BC, FG, & am­pulla AB, repleantur, relinquaturque &longs;patium &longs;upre­mæ fi&longs;tulæ ID aere plenum, arctè po&longs;teà claudatur &longs;upremum orificium D &longs;uilla ve&longs;ica; tandèm flecta­tur deorsùm fi&longs;tula collateralis FG, ab eius &longs;upremo ore G pro&longs;&longs;uens mercurius excipiatur va&longs;e MN,

quou&longs;que infima mercurij libella &longs;it LO, & &longs;uprema &longs;uperficies eiu&longs;dem mer­curij &longs;tagnantis &longs;it H reli­cto nempè &longs;patio vacuo DABH, quia verò cylin­drus aereus DI dilatatur, explicaturque pro eius ge­nio in &longs;patio vacuo ibidem relicto, fit vt po&longs;&longs;it ali­quando po&longs;t eius dilatatio nem integrè, & totalitèr occupare &longs;patium DABH, & tunc cum non po&longs;&longs;it am­pliùs explicari &longs;ua virtute

elatere non impellet deorsùm &longs;uperficiem hydrar­gyri H, & ideò &longs;umma altitudo mercurij HO erit inalterata, &longs;cilicèt omnium maxima earum, quæ fie­ri po&longs;&longs;unt vnius cubiti & quadrantis proximè, & tunc experientia con&longs;tat aerem DI maximè dilatatum in­tra &longs;patium DABH occupare locum 180. maiore&mtail; quam prius. &longs;uppo&longs;ita hac cognitione ab experientia deducta denuò operatio repetatur, & con&longs;tat quod omnes moles aeris non excedentes &longs;patium DI non depriment mediocrem mercurij eleuationem OH; & è contrà omnes aeris moles excedentes DI compriment mercurium efficientque altitudinem OK minore&mtail; men&longs;ura con&longs;ueta vnius cubiti, & quadrantis proxi­mè, & hoc profectò non fui&longs;&longs;e à docti&longs;&longs;imo viro ani-maduer&longs;um facilè con&longs;tat, non enim dixi&longs;&longs;et: &longs;i tantu­lum aeris antequam demittatur mercurius in fistula, relin­quatur mercurius de&longs;cendet infra H. vbi &longs;u&longs;tineri debuerat &longs;i ab aeris cylindro &longs;u&longs;tinebatur. reuerà enim quælibet portiones aeris minores &longs;patio ID fummam altitudi­nem mercurij in fi&longs;tula non deprimunt, quia nimirùm aereus cylindrus eiu&longs;dem roboris æquali vi compri­mit mercurium &longs;ubiectum. At quando aeris moles maior ID ibidem includitur, tunc virtute eius elate­ria, vt po&longs;tea dicemus, vim facit contra impul&longs;u&mtail; aeris externi, nempè cylindrus mercurij HO æquili­bratus ab aere externo impellitur &longs;ursùm ab O ver­sùs H, ab aere verò inclu&longs;o intra ampullam AB, dum conatur &longs;e dilatare repellitur deorsùm ab H versùs O. Vis ergo aeris comprimentis mercurium &longs;tagnan­tem L agit contra duas re&longs;i&longs;tentias, &longs;cilicèt contra pon­dus mercurij HO, & contra vim exiguam aeris in­clu&longs;i &longs;e dilatare conantis; igitur in hoc ca&longs;u minor erit altitudo mercurij OK quam HO, licet producatur ab eadem aeris virtute premente; Niligitur ex hac ter­tia aduer&longs;arij ratione deducitur contra aeris pre&longs;&longs;io­nem, & æquilibrium cum mercurio inclu&longs;o intra fi­&longs;tulam.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Quarta ratio eadem ferè e&longs;t cum prima, ad eamque reducitur. quinta verò pendet ex eo quod &longs;patiu&mtail; &longs;upremum fi&longs;tulæ po&longs;t mercurij lap&longs;um non vacuum, &longs;ed repletum e&longs;&longs;e ait ex materia quadam tenui&longs;&longs;ima, &longs;ed valdè ten&longs;a de qua re &longs;uo loco di&longs;putabimus; in­terim incidenter noto eius verba dum ait, tantam ae-ris compres&longs;ionem &longs;en&longs;ui repugnare: cum inclinata fi&longs;tula derume&longs;cat ve&longs;ica, antequam &longs;uperficies mercurij ad illam perueniat.

Quarta, & quinta ratio eiu&longs;dem au­thoris.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CVI.

Ve&longs;ica cyprina inflata Roberuallij in &longs;ummitate fictulæ Tor­ricellianæ non &longs;emper detume&longs;cit po&longs;t huius inclinatio­nem, & ratio huius effectus redditur.

HOc profectò non &longs;emper accidit, præcipuè quan­do &longs;i&longs;tula capacem ampullam in &longs;ummitate ha­bet, in ea enim commodè aliqua aeris portio, quæ sen­per in fi&longs;tulæ &longs;uprema parte remanet, aut ibidem col­ligitur reduciturque po&longs;tquàm &longs;egregatur à mercu­rij &longs;ub&longs;tantia, per quam a&longs;cendunt innumera granula aerea partim vi&longs;ibilia, partim incon&longs;picua ob minu­tiem, & hæc quidem ad &longs;upremam mercurij &longs;uperfi­ciem a&longs;cendunt, & prout magis ad &longs;patium vacuum appropinquantur, eo magis cre&longs;cunt bullæ aereæ, in­fianturque, & tandem expanduntur, di&longs;&longs;iliunt rumpun­turque in prædicto &longs;patio vacuo, & hoc magis euiden­ter ob&longs;eruatur &longs;i &longs;uprema hydrargyri cylindri &longs;uper­ficies exigua aquæ portione cooperiatur, tunc gra­nula aerea à mercurio a&longs;cendentia videri po&longs;&longs;unt in tran&longs;itu per aquam tran&longs;picuam, quæ &longs;peciem repre­&longs;entant ebullitionis cuiu&longs;dam compo&longs;itæ ex prædi­ctis particulis aereis inflatis, & veloci&longs;&longs;imè &longs;ursum ex­currentibus. His po&longs;itis ve&longs;icula illa cyprina Rober­uallij inclinata fi&longs;tula &longs;olet detume&longs;cere antequa&mtail; mercurius eam attingat, propterea quòd partes illæ aereæ, quæ priùs &longs;ummè dilatatæ erant in amplo &longs;pa­tio inani in &longs;ummitate fi&longs;tulæ, po&longs;tea re&longs;tricto &longs;patio ob mercurij a&longs;cen&longs;um denuò conden&longs;antur, & proin­dè mirum non e&longs;t ve&longs;icam cyprinam ab aere eam am­biente den&longs;iori, quàm &longs;it aerintra ve&longs;icam contentus, compre&longs;&longs;ionem pati debere, & proinde detume&longs;cere.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateria eius.

Quando verò &longs;ubdit, quod aer intra fi&longs;tulam im­mi&longs;&longs;us dum mercurius eleuatus e&longs;t ad prædictam al­titudinem cubiti vnius, & quadrantis proximè, &longs;ursum fertur tanto impetu, vt &longs;upremum fi&longs;tulæ fundum, & ba&longs;is diffringatur; di&longs;&longs;iliatque, & quia ab exce&longs;&longs;u exi­gui ponderis tantus impetus creari non pote&longs;t, hinc deducit non po&longs;&longs;e à cylindro aeris ambiente, & ab eius pondere vllo pacto impelli neque mercurius, ne­que aer in prædicta fi&longs;tula.

PROP. CVII.

Aer in fi&longs;tula Torricelliana adueniens nedùm pondere, &longs;ed vi ela&longs;tica, & impetu in motu acqui&longs;ito diffringere fundum &longs;upremum fistulæ pote&longs;t.

HVic difficultati occurro con&longs;iderando quòd mer­curius in fi&longs;tula &longs;ursùm impellitur ab aere ex­terno non vnica, &longs;ed triplicivi, ponderis nimirum, virtutis ela&longs;ticæ ad modum machinæ, & impetus in motu acqui&longs;iti: &longs;ed præcipua, & in&longs;ignis actio in ca­&longs;u no&longs;tro impetui tribui debet. Quia po&longs;tquam è fi&longs;tula cum mercurio extante in aere pendula effluit gutta aliqua mercurij &longs;ubito ce&longs;&longs;at æquilibrium, & ideò maius pondus collateralis columnæ aereæ po­te&longs;t &longs;ursùm intra fi&longs;tulam impellere molem minus pon­derantis mercurij inclu&longs;i; & licèt ab initio motus mer­curij &longs;ursùm &longs;it tardus, & debilis, tamen in progre&longs;­&longs;u, & continuatione prædicti motus dum repetitis ictibus mercurius ab aeris pondere, & vi eius ela&longs;ti­ca continenter impellitur, nouos gradus impetus, & velocitatis creat, qui impetus &longs;unt integri, & eiu&longs;dem energiæ, non enim à vacuo intra fi&longs;tulam inclu&longs;o de­bilitari po&longs;&longs;unt, veluti debilitantur impetus corporum per aerem excurrentium; prædicti verò gradus velo­citatum &longs;imul coaceruati, tandem vim illam ingentem componunt, quæ diffringere fundum vitreæ fi&longs;tulæ pote&longs;t; adde quod corpora graui&longs;&longs;ima; vt e&longs;t hydrar­gyrum validius fu&longs;cipiunt retinentque vim impetus præconcepti, & hinc &longs;equitur percu&longs;&longs;io eius validi&longs;­&longs;ima in vitri fundum. Supradictum ratiocinium abip­&longs;a experientia con&longs;irmari videtur; &longs;i enim fi&longs;tula præ­longa &longs;ubtili, & gracili fundo clau&longs;a, & mercurio ple­na inuer&longs;o ore infra mercurium in &longs;cutella &longs;tagnantem demer&longs;a, & inclinato &longs;itu detineatur vt mercurius minus vno digito à &longs;upremo fundo di&longs;tet, tunc &longs;u­&longs;pen&longs;a fi&longs;tula aer adueniens fundum eius non diffrin­git, at perpendiculari &longs;itu erecta fi&longs;tula aer &longs;uccedens ingenti impetu di&longs;tantem à fundo mercurium propel­lit vt eum diffringat, quia nimirum in prolixiori mo­tu plures gradus impetus creari, & &longs;imul coaceruari po&longs;&longs;unt.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateria eius.

De-vicap. 22.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateria eius.

Po&longs;tea &longs;ubdit: Cylindrus aeris exterioris à quo (vt non­nulli volunt) mercurij extantis &longs;egmentum &longs;u&longs;tinetur, ne­que plus, neque minus pote&longs;t &longs;ustinere, igitur &longs;i ferrum can­dens admoueatur &longs;egmento vacuo fi&longs;tulæ, nulla e&longs;t ratio cur &longs;uperficies &longs;uprema mercurij &longs;ub&longs;idat. Sub&longs;idit tamen. Siverò nix, vel trita glacies admoueatur, mercurius attolli­tur.

Sextum ar­gumenturn.

PROP. CVIII.

Igneæ exhalationes corporeæ vehementis&longs;ima agitatione tum per &longs;e, cum variè impellendo, & torquendo particulas aeris in &longs;ummitate fistulæ Torricellianæ reli­ctas, facilè po&longs;&longs;unt &longs;ub&longs;identem mercu­rium æquilibratum deprimere.

RE&longs;pondeo, quòd igneæ particulæ nedùm &longs;e ip­&longs;as vehementèr agitant, commouentque, &longs;ed præterea aereas quoque particulas in vitri &longs;ummita­te inclu&longs;as, vt dictum e&longs;t, vehementi&longs;&longs;imè impellunt; porrò quia quodlibet corpus æquilibratum pote&longs;t à quacumque exigua vi agitari, (vt demon&longs;trauimus in no&longs;tro opere de vi percu&longs;&longs;ionis) &longs;itque prædictus mercurius in fi&longs;tula æquilibratus cum æquiponderan­te cylindro aereo externo, igitur nece&longs;&longs;ariò ab inte­ftina illa agitatione ignearum, & aerearum particu­larum &longs;uper&longs;icies mercurij percu&longs;&longs;a propelli pote&longs;t, & ideò deprimi infra con&longs;uetam eius altitudinem de­bet, è contrà adhibitaniue, vel trita glacie, &longs;patium illud dumigne priuatur, & deficit quoque agitatio, & reuolutio nedum particularum ignis, &longs;ed etia&mtail; aeris contenti, propterea præualere pote&longs;t exce&longs;&longs;us grauitatis aeris ambientis &longs;upra mercurium in fi&longs;tu­la eleuatum.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateria eius.

Affert po&longs;tea &longs;eptimam rationem: Si po&longs;tquam mer­curius &longs;ub&longs;idit vas infimum claudatur vt nulla rima &longs;u-per&longs;it, per quam aer &longs;ubeat, non tamen propterea mercurius &longs;ub&longs;idit, &longs;ed tunc non &longs;u&longs;tinetur à cylindro aeris, quia &longs;cili­cèt non est applicatus.

Septima in­&longs;tantia.

Huic argumento primus omnium re&longs;pondit Cla­ri&longs;&longs;imus Torricellius in epi&longs;tola ad Clari&longs;&longs;imum Mi­chaelem Angelum Riccium mi&longs;&longs;a, quam humani&longs;&longs;i­mè mihi communicauit anno 1658. eamque Floren­tiæ po&longs;teà Sereni&longs;&longs;imo Principi Leopoldo tradidi, & inter amicos euulgaui.

PROP. CIX.

Licèt operculo impediatur aeris pres&longs;io &longs;upra mercurium &longs;ta­gnantem in &longs;cutella, tamen quia aer relictus ibidem remanet eodem modo pre&longs;&longs;us, & con&longs;tipatus ac prius pote&longs;t mercurium in fistula ad eamdem altitudinem re­tinere.

IS habet, quod quando intercipitur prohibeturque commercium inter ambientem aerem, & eum, qui immediatè &longs;uperficiem &longs;tagnantis mercurij tangit po&longs;ito nimirùm operculo, vt v. g. quando in fi&longs;tul&atail; inflexa ABG mercurius eleuatur v&longs;que ad altitudinem BF vnius cubiti, & quadrantis relicto &longs;patio inani AF, & po&longs;ito quod prædicta mercurij &longs;ublimatio de­pendeat à compre&longs;&longs;ione, quam cylindrus aereus SD v&longs;que ad &longs;upremam aeris &longs;uperficiem exten&longs;us &longs;u&atail; grauitate efficiat &longs;upra &longs;tagnantem mer­

curium D, &longs;equitur, quod &longs;i occludatur orificium G eiuldem fi&longs;tulæ remanebit portio aerea intercepta GD eodem mo­do compre&longs;&longs;a re&longs;trictaque vt priùs, quia nimirùm digitus, vel operculum reti­net con&longs;eruatque aerem in eadem po­&longs;itione, & con&longs;trictione, quam prius ab incumbente aere patiebatur. Eode&mtail; ferè modo, ac &longs;iloco aeris &longs;uperpone­rentur mercurio plures cylindri lapidei vnus &longs;uper alterum incumbens, tunc profectò infimus cylindrus comprime­ret &longs;uperficiem &longs;ubiecti hydrargyri D non tantùm energia ponderis proprij, &longs;ed vi conflata ex grauitate omnium incumbentium cylindrorum modò ablatis &longs;emoti&longs;que &longs;upremis om­nibus columnis &longs;i in fimus cylindrulus, tantummodò tabula, vecte, aut quo cumque alio retinaculo eadem vi fixè in eodem &longs;itu retineretur, patet quòd æquali energia comprimeret &longs;ubiectam mercurij &longs;uperficiem D ac priùs premebatur à prælonga illa &longs;erie colum­narum incumbentium; Et hic dicendum e&longs;&longs;et, quòd cau&longs;a immediata impellens mercurium non e&longs;t longa illa &longs;eries columnarum SD, &longs;ed o&longs;t infimus cylindru­lus GD qui tanta vi comprimit &longs;ubiectum mercurium quanta e&longs;t grauitas omnium columnarum SD; itaque grauitas omnium columnarum appellari pote&longs;t cau­&longs;a productiua illius compre&longs;&longs;ionis, quam facit infi­mus cylindrulus GD mercurio immediatè contiguus, quia verò huiu&longs;modi effectus remanet, quando clau­ditur orificium G, remouenturque columnæ &longs;upre­mæ, igitur æquali vi, & æquali men&longs;ura debet mer­curius BF &longs;ublimari. Id ip&longs;um dici debet de aere SD, certum profectò e&longs;t dum orificium G e&longs;t apertum cy­lindrum aereum GS v&longs;que ad aeris &longs;upremam &longs;uper­ficiem exten&longs;um comprimere cylindrulum aereu&mtail; GD tanta vi quanta exigit energia grauitatis aeris SG, quando verò digito, vel operculo impeditur con­tactus, & compre&longs;&longs;io aeris &longs;upremi SG remanet cy­lindrulus aereus GD eodem modo compre&longs;&longs;us re&longs;tri­ctu&longs;que, ac prius igitur nece&longs;&longs;ario eodem modo &longs;ub­iectum mercurium D premet proindeque ad eamdem altitudinem BF eum &longs;ubleuabit.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CX.

Idip&longs;um confirmatur in aquæ.

VEritas huius a&longs;&longs;erti alio experimento confirma­tur: Demergatur in aliquo puteo RV aqua ple­no eadem fi&longs;tula ABG cum mercurio extante FB, vi­demus quod aliquanti&longs;per mercurius infra libellam D deprimitur à pondere incumbentis aquæ ND, quæ paritèr altiùs mercurium in fi&longs;tulam &longs;ubleuat per &longs;pa­tium BH, vt nimirùm exce&longs;&longs;us FH &longs;upra eam eleua-tionem, quæ in libero aere efficiebatur, &longs;it pars de­cimaquarta altitudinis aquæ ND. in hoc rerum &longs;ta­tu digito, vel quolibet alio operculo claudatur fi­&longs;tulæ o&longs;tium G hic iamce&longs;&longs;at om­

ninò actio, & compre&longs;&longs;io ponderis cylindri aquei NG, & tamen mer­curius in eodem &longs;igno fi&longs;tulæ H per&longs;euerat, igitur eodem modo in aere occlu&longs;o o&longs;tio G per&longs;eue­rare, & retineri debet mercurius &longs;ubleuatus v&longs;que ad F mediatè qui­dem à pondere aeris qui prius incun­bebat, &longs;ed modo immediatè ab illa compre&longs;&longs;ione, & re&longs;trictione, quam produxerat pondus incumbentis aeris SG. vnde con&longs;tat quod mercurius in fi&longs;tula ele­uari pote&longs;t à pondere aeris ambientis, nec adduct&atail; difficultas hanc &longs;ententiam debilitat aut de&longs;truit.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Subdit po&longs;tea pro confirmatione &longs;ui ratiocinij: Iam verò facilè ostendo non &longs;ustineri, &longs;eu &longs;u&longs;pendi in BF eò quod aer interceptus inter operculum, & &longs;uperficiem vlte­riori compre&longs;sioni re&longs;istat, nempè &longs;i admoto dicto operculo, & extante mercurio in BF aperiatur foramen in A mercurius illicò infra F de&longs;cendit, idque notabili &longs;egmento, &c.

Hoc ratio­cinium cona tur refellere aduer&longs;arius.

Sibi ip&longs;i po&longs;tea opponit dicendo, quòd mercurius deorsum impellitur duplici vi, propriæ &longs;cilicèt grauita­tis mercurij BF, & ponderis aeris per &longs;upremum foramen fluentis, quid mirum &longs;i præualeat, interceptumque ae­rem vlteriùs comprimat, & mercurium infra F depri­mat. po&longs;tea huic argumento re&longs;pondet: Dico non ma-gis comprimi aera interceptum inter D, & dictum opercu­lum à mercurio FB, & cylindro aeris grauitantis per fora­men A, quam remoto operculo, & clau&longs;o foramine A ab eo­dem mercurio BF & eodem cylindro aeris exterioris, nam perindè e&longs;t &longs;iue tota vis pre&longs;sionis per lineam vnicam inci­dat, vel applicetur; &longs;iue &longs;ubduplum per vnam, & &longs;ubdu­plum per oppo&longs;itam. Vnde (paucis interceptis conclu­dit) per&longs;picuè deduco non ideo admoto &longs;cilicet operculo in G extare mercurium BF, & minimè &longs;ub&longs;idere, quia &longs;cilicet dictus aerinterceptus comprimi vltra non pote&longs;t, &longs;ed alia de cau&longs;a, &c.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Sed pace tanti viri, aio, verum non e&longs;&longs;e eius a&longs;&longs;ump­tum, demon&longs;trabo enim quod clau&longs;o vitro in G, & a­perto in A vis, qua comprimitur aer FB duplò vali­dior e&longs;t ea, qua comprimitur clau&longs;o vitro in A, & a­perto in G, pro cuius intelligentia præmittenda e&longs;t &longs;equens.

PROP. CXI.

Anulus, vel ve&longs;ica aere plena æquè ab vnica & &longs;ub­dupla potentia comprimitur con&longs;tringiturque, quàm à dupla, &longs;eu à duabus potentijs illi æqualibus vtrinque anulum, vel ve&longs;icam constringentibus.

SIt ABC anulus calybeus, vel ve&longs;ica aere plena, & primò comprimatur à duabus potentijs contrarijs, & inter&longs;e æqualibus P, & E, &longs;eu G. Et quia vnaquæque potentiarum P tunc præcisè æquilibratur re&longs;i&longs;tentiæ, &longs;eu energiæ compre&longs;&longs;ionis, quam patitur pars B, quan­do ambo po&longs;t flexionem, & motum quie&longs;cunt; ergo momentum potentiæ P æqua­

le e&longs;t momento re&longs;i&longs;tentiæ, &longs;eu energiæ, compre&longs;&longs;ionis, quam patitur B, & fiunt ni&longs;us per eamdem rectam perpendi­cularem ad horizontem, igi­tur ab&longs;oluta potentia P æ­qualis| e&longs;t re&longs;i&longs;tentiæ ab&longs;olutæ, &longs;eu vi compre&longs;&longs;ionis, quam patitur B. Pari ratione ab&longs;oluta potentia E, vel G æquatur re&longs;i&longs;tentiæ, &longs;eu vi compre&longs;&longs;ionis partis op­po&longs;itæ C. vnde deducitur duas potentias P & E, &longs;eu G &longs;imul &longs;umptas æquales e&longs;&longs;e re&longs;i&longs;tentiæ integræ, &longs;eu vi totali compre&longs;&longs;ionis, quam patitur anulus, vel ve­&longs;ica ABC.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateria eius.

Po&longs;tea &longs;ub&longs;tituatur pauimentum durum RS loco potentiæ flectentis E, vel G, & &longs;olummodo &longs;upernè anulus, vel ve&longs;ica aerea comprimatur à potentia P &longs;cilicet à &longs;emi&longs;&longs;e potentiarum P, & E. Dico anulu&mtail;, vel ve&longs;icam aeream æquè con&longs;tringi, ac priùs à dua­bus potentijs contrarijs contundebatur. Quia paui­mentum &longs;tabile RS perinde reagit impediendo mo­tum, & de&longs;cen&longs;um ponderis P, ip&longs;umque in eodem &longs;i­tu quiete &longs;tabili permanere cogit, ac operatur manus &longs;ubiecta E, vel pondus G mediante libra FE, ergo &longs;tabilitatis &longs;oli momentum æquatur momento, & po­tentiæ ab&longs;olutæ ip&longs;ius E, &longs;eu P. quare anulus, &longs;eu ae­rea ve&longs;ica BC comprimitur non à &longs;ingulari, & &longs;ubdu-pla potentia P, &longs;ed a duplici

potentia, tanquam à forcipe, vel prælo, nempè à P, & ab huic æquali re&longs;i&longs;tentia paui­menti RS. Igitur æquè com­primetur anulus, vel ve&longs;ica aerea &longs;olo innixa à &longs;ingulari potentia P, ac &longs;i à duabus contrarijs potentijs P, & E, vel G con&longs;tringeretur.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateria eius.

COROLLARIV M.

HInc patet, quòd &longs;i duæ potentiæ æquales &longs;imul coniunctæ comprimant eumdem &longs;upremu&mtail; anuli terminum pauimento innixi, tunc momentu&mtail; fiue energia, qua anulus contunditur &longs;tringiturqu&etail; duplex e&longs;t eius, qua ab ij&longs;dem potentijs oppo&longs;itos terminos &longs;tringentibus comprimitur.

Quia quotie&longs;cum que duæ potentiæ inter &longs;e æqua­les P & G premunt &longs;upremum terminum B anuli BC, tunc &longs;olum &longs;tabile RS in E, cui innititur idem præ&longs;tat, & tanta energia operatur, ac &longs;i in E ade&longs;&longs;et potenti&atail; æqualis ambabus contrarijs potentijs G & P: quare vis, qua &longs;tringitur anulus æqualis e&longs;t duplo potentia­rum G, & P. è contrà quando anulus &longs;tringitur ab ij&longs;­dem potentijs G, & P &longs;ubdiui&longs;is, &longs;cilicèt à potenti&atail; P in &longs;itu B, atque à potentia G in oppo&longs;ito eius ter­mino C vt in præcedenti figura videre e&longs;t, tunc vis, qua &longs;tringitur anulus, æqualis e&longs;t præcisè duabus po­tentijs oppo&longs;itis G, & P, igitur quando anulus &longs;olo innixus&longs;tringitur ab ij&longs;dem potentijs G, & P in B du­plici energia con&longs;tringitur, contunditurque quam &longs;i ab ij&longs;dem duabus potentijs G, & P &longs;ubdiui&longs;is con&longs;trin­geretur.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateria eius.

PROP. CXII.

In Torricelliana fi&longs;tula mercurio extante, clau&longs;o ori&longs;icio &longs;cutellæ, & aperta &longs;ummitate fi&longs;tulæ, aer in &longs;cu­tella interceptus inter mercurium, & operculum à vi duplò validiori comprimitur, quàm illo aperto, & hoc clau&longs;o.

IN fi&longs;tula Torricelliana ACG aper­ta in G, & clau&longs;a in A, facto vacuo,

more &longs;olito, remanente mercurio BF eleuato &longs;upralibellam BD; patet ex ip­&longs;iu&longs;met aduer&longs;arij hypothe&longs;i, quòd aer in &longs;cutella, &longs;eu ampulla DG con­tentus &longs;tringitur, comprimiturque à duabus potentijs contrarijs inter &longs;&etail; æqualibus (eò quod æquilibrantur) nempè à pondere mercurij extantis BF, & à pondere columnæ aereæ GS. Si po&longs;tea appo&longs;ito operculo exactè clau­datur orificium G, & aperiatur orificium in &longs;ummitate fi&longs;tulæ A aer interceptus inter operculum G, & mercurium D &longs;tringitur comprimiturque à mercuio BF, & à colum-na aerea FS æquali ip&longs;i GS, tunc patet, quòd poten­tiæ comprimentes mercurij FB, & aeris FS æquales &longs;unt potentiæ eiu&longs;dem mercurij FB, & aeris SG. Iam dico, quod duplò validiori vi comprimitur aer DG clau&longs;o orificio G, & aperta &longs;ummitate A, quàm illo aperto, & hoc clau&longs;o. Quia obturato vitro in A, & a­perto in G ampulla aerea DG &longs;tringitur à duabus oppo&longs;itis potentijs, à mercurio nempè FB, & ab aeris columna SG, ergo vis, qua aerea ve&longs;ica DG &longs;tringitur æqualis e&longs;t duabus potétijs mercurij BF, & aeris SG, &longs;eu duplò ponderis mercurij BF. è contra clau&longs;o ori­&longs;icio G, & aperto vitro in A duæ potentiæ mercurij BF, & aeris SF comprimunt aerean|veficam DG in D, qui aer innititur fundo &longs;tabili, nempè operculo G, igitur, ex corollario præcedentis, propo&longs;itionis vis, qua aer DG &longs;tringitur æqualis e&longs;t duplò potentiarum mèrcu­rij BF, & aeris SF, nempèl quadruplò potentiæ mer­curij BF; igitur dupla vi, & energia con&longs;tringitur aer DG clau&longs;o orificio G, & aperto vitro in A, ac compri­mebatur quando vitrum claudebatur in A, re&longs;eraba­tur verò in G.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateria eius.

Ex 1. parte top. III. 111.

Quod verò à maiori vi compre&longs;&longs;iua, nempè dupla magis con&longs;tringi, conden&longs;arique debeat aer DG, & proinde mercurius deprimatur infra &longs;upremam ele­uationem F mirum profectò non e&longs;t, imò iuxtà ordi­nem naturæ, & nece&longs;&longs;itatem, qua operatur debet mercurius in prædicto ca&longs;u aliquantulum deprimi, vt exigit aeris natura, quæ dilatationi, & con&longs;trictioni obnoxia e&longs;t. Hinc con&longs;tat ab aere compre&longs;&longs;o DG pro-hiberi de&longs;cen&longs;um mercurij BF, quæ compre&longs;&longs;io facta fuit à cylindro aereo incumbente SG ope eius na­tiuæ grauitatis.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Non e&longs;t nece&longs;sè vt hìc repetam experimenta innu­mera, quæ pa&longs;&longs;im obuia sunt, de quibus Roberuallius, Mer&longs;ennus, Pecquetus, Boile, Ga&longs;&longs;endus, & plures alij&longs;crip&longs;erunt, & tandem prodijt liber experimen­torum no&longs;træ Academiæ Experimentalis Mediceæ; ex his enim euincitur, ab aere ambiente mercuriu&mtail; in fi&longs;tula &longs;ubleuari, quandoquidem quotie&longs;cumque aer ex&longs;ugitur, &longs;eu prohibetur eius compre&longs;&longs;io &longs;uper &longs;tagnantem mercurium, tunc deprimitur mercurius infra &longs;upremum &longs;ignum in fi&longs;tula, & &longs;i hoc fiat in &longs;pa­tio vacuo, &longs;cilicètin loco à quo aer exclu&longs;us &longs;it, tunc quidem mercurius omninò deprimitur, & è contrà adueniente aere &longs;ubitò mercurius in prædicta fi&longs;tula eleuatur. idip&longs;um accidit in aqua.

PROP. CXIII.

Suadetur aeris difformis grauit as ex inæquali mercurij ele­uationein fi&longs;tula, prout altitudo aeris maior, aut mi­nor fuerit.

PRætere a euidenti&longs;&longs;imum e&longs;t, mercurium in prædi­ct a fi&longs;tula eò magis deprimi infra altitudine&mtail; vnius cubiti, & quadrantis, quò magis in&longs;trumentum eleuatur à plano &longs;ubiecto, &longs;ic Dominus Pa&longs;chalius in montibus Aruerniæ expertus e&longs;t in radice montis mercurij altitudinem fui&longs;&longs;e pollicum 27. cum tribus lineis: translato in&longs;trumento ad altitudinem pedu&mtail; 900. &longs;upra montis radicem, mercurij altitudo fuit&longs;o­lummodò pollicum 25. in cacumine verò montis vbi altitudo ab eius radice erat pedum 3000. eleuatio mercurij fuit pollicum 24. lin. 2. con&longs;tat ergo nedùm minui compre&longs;&longs;ionem quando minuitur aeris altitu­do, &longs;ed etiam euincitur difformitas grauitatis ip&longs;ius aeris; conijcitur enim, quòd aer habeat con&longs;i&longs;tentiam veluti &longs;pongio&longs;am &longs;itque veluti lanæ cumulus, cuius partes &longs;uperiores dum comprimunt infimas, reddunt aeris regionem difformiter grauem pro varia earu&mtail; compre&longs;&longs;ione, & con&longs;tipatione, & pro varia mi&longs;tu­ra particularum aquæ, & terræ.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Idip&longs;um po&longs;tea ob&longs;eruauimus Florentiæ in alti&longs;&longs;i­ma turri palatij, in qua a&longs;cen&longs;is &longs;olummodò cubitis 50. &longs;upra infimam plateam, & palatij atrium depre&longs;­&longs;us apparuit mercurius &longs;patio vnius gradus, &longs;cilicèt decima parte vnius digiti, at po&longs;tea perducto in&longs;tru­mento ad altitudinem 100. cubitorum depre&longs;&longs;io mer­curij minor fuit altero gradu euidenti, & notabili defectu. Idemque po&longs;tea ob&longs;eruatum fuit in monti­bus propè Florentiam, & ne &longs;u&longs;picio &longs;ubiret aeris &longs;u­premi frigiditatem depre&longs;&longs;i&longs;&longs;e mercurium in fi&longs;tul&atail; elegimus loca, & tempora commoda, &longs;cilicèt calefa­cta à &longs;ole in turris cacumine, & vmbro&longs;a in eius ra­dicibus, vt eorum temperies eadem e&longs;&longs;et, & hoc in­dicabatur adhibitis perfecti&longs;&longs;imis termometris, quç o&longs;tendebant aerem in &longs;ummitate turris, aut eade&mtail; temperic, aut calidiori &longs;eruari quem in radice turris aut montis. & ne &longs;u&longs;picio &longs;ubiret à concu&longs;&longs;ione mer­curij in fi&longs;tula dum transferebatur &longs;ursùm exclu&longs;is particulis minimis aereis, debui&longs;&longs;e po&longs;tea mercurium aliquanti&longs;per deprimi, curauimus etiam obturato in­fimo fi&longs;tulæ orificio, ne vlla concu&longs;&longs;io mercurij effice­retur, & po&longs;tea in ip&longs;o de&longs;cen&longs;u vidimus præcisè mercurium in ij&longs;dem locis eleuatum fui&longs;&longs;e ad ea&longs;dem altitudines, ad quas in a&longs;cen&longs;u montis, vel turris per­uenerat, vnde colligitur &longs;olummodò ab aeris vari&atail; compre&longs;&longs;ione mercurium &longs;uas altitudines varia&longs;&longs;e.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Altitude mercurij in fi&longs;tula Torri­celliana non &longs;emper eiu&longs;­dem men&longs;u­ræ e&longs;t.

Vltimo loco animaduertimus non &longs;emper mercu­rium ad eamdem præcisè altitudinem in fi&longs;tula ele­nari, quæ aliqua ex parte pendet à temperie aeris calida, & frigida, &longs;ed hæc quidem exigua e&longs;t &longs;i vi­trea fi&longs;tula in vertice eius &longs;upremo annexam ampul­lam vacuam, amplam habeat; mirabilis profectò vi­&longs;a e&longs;t variatio illa altitudinis, quæ procùl dubio à ten­perie calidi, & frigidi aeris non dependet, cum perin­de ob&longs;eruata &longs;it temporibus æ&longs;tiuis, & hyemalibus, pariter que in cubiculo ab igne excalefacto, vel fri­gido, et habeo penès me ob&longs;eruationes duorum anno­rum 1657. & 1658. prædictarum varietatum, in quibus &longs;ingulis diebus adnotantur gradus caliditatis aeris ex termometro, an dies fuerit ne bulo&longs;us, vel pluuius, aut &longs;erenus, & quinam venti &longs;pirarint, quas feci mo­nitu, & iu&longs;&longs;u Sereni&longs;s. Ferdinandi Secundi M. Ducis Ætruri&ecedil;, naturalium operationum &longs;agaci&longs;&longs;imi explo­ratoris: & tandem videtur ex pluribus ob&longs;eruatio­nibus &longs;imùl collectis deduci po&longs;&longs;e, quòd multoties

cùm imminet aliqua diuturna, & continuata pluuia in illa regione, tunc mercurius in fi&longs;tula per aliquos gradus &longs;upra con&longs;uetam altitudinem eleuatur, è con­trà pluuia iam actu cadente mercurius in prædicta &longs;i­&longs;tula deprimi &longs;olet, nec e&longs;t exigua prædicta differen­tia, multotiès enim Pi&longs;is ob&longs;eruaui in diuturnis plu­uio&longs;is tem pe&longs;tatibus varia&longs;&longs;e mercurij altitudine&mtail; per duodecim gradus, &longs;cilicèt per latitudinem vnius pollicis. Quia verò a&longs;&longs;eruo penès me exemplar epi­&longs;tolæ, quam Sereni&longs;&longs;imo Principi Leopoldo modò Cardinali ampli&longs;&longs;imo anno 1657. &longs;crip&longs;i circa hanc materiam, hìc afferam breuiter ea, quæ tunc &longs;pecu­latus &longs;um, quod nimirùm fieri pote&longs;t ob aeris pre&longs;­&longs;ionem &longs;upra mercurium &longs;tagnantem in fi&longs;tula, vt an­te pluuiam aer multò magis grauitet, & comprimat, quam in ip&longs;o pluuiæ de&longs;cen&longs;u, quod vt clariùs o&longs;ten­dam, præmittendum e&longs;t.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXIV.

In fi&longs;tula Torricelliana intra puteum demer&longs;a &longs;i aqua à grauiori &longs;uper addito fluido occupetur, mercu­rius in fistula altiùs &longs;ubleuatur, at post illius delap&longs;um denuo mercurius deprimitur.

SVmpta fi&longs;tula vitrea ABC flexa in B, & facto i&ntail; ea vacuo, more &longs;olito, mercurius eleuetur v&longs;que ad F, demittatur po&longs;tea fi&longs;tula intra vas vitreum cy­lindricum DE maxim&ecedil; altitudinis earum quæ exca-uari efformarique po&longs;&longs;unt, atque in eius fundo E de­mittatur fi&longs;tula cum &longs;tagnante mercurio ABC; po&longs;tea repleatur cylindrus vitreus oleo, vel alio liquore le­uiori v&longs;que ad G, con&longs;tat à nouo pondere olei &longs;upra mercurium &longs;tagnantem C incumbentis eleuari præ­terea mercurium ab F ad H, vt nimirum fiat æquili­brium inter mercurium HF, & oleum

CG; po&longs;tea &longs;i&longs;upra olei &longs;uperficiem G innatet vas NO, quod arena, a­qua, vel alio grauiori fluido non om­ninò impleatur, procùl dubio à no­uo pondere NO altiùs mercurius eleuabitur in fi&longs;tula ab H v&longs;que ad M. His peractis reuoluatur vas N O, vt nimirum arena, vel a qua flue­re po&longs;&longs;it deorsùm ad modum pluui&ecedil; per &longs;patium oleo&longs;um GC, & dùm prædicta pluuia deorsùm de&longs;cendit non de&longs;eret mercurius &longs;ummitatem fi&longs;tulæ M, at po&longs;tquam areno&longs;a, vel aquea pluuia fun­dum cylindri EK atting it, & proindè infrà &longs;tagnantem libellam mercurij C de primitur, tunc mercurius non ampliùs per&longs;i&longs;tet in &longs;ummitate &longs;i&longs;tulæ M, &longs;ed paula­tim de&longs;cendet versùs H, prout maiori copia pluui&atail; aquea, vel areno&longs;a ad fundum va&longs;is EK perducitur. ra­tio huius rei e&longs;t quia licèt arena, vel aqua grauior o­leo &longs;it, & proindè comprimat mercurium &longs;tagnantem in C, eumque eleuet v&longs;que ad M, nihilominùs quan­do arena, vel aqua fundum va&longs;is EK attingit, compri-mit eius fundum, non verò &longs;uperficiem &longs;tagnantis mer­curij C, & &longs;ic mercurius comprimitur tantummodò à cylindro oleo&longs;o GC.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXV.

Mercurius in fi&longs;tula Torricellian a altiùs eleuabitur dum aer nebulis pluuio&longs;is impregnatur, at postquam pluuia delap&longs;a e&longs;t, denuò mercurius in fistulæ deprimitur.

AB hoc euidenti&longs;&longs;imo experimento problema no­&longs;trum &longs;olui po&longs;&longs;e cen&longs;eo, quandoquidem quid aliud &longs;unt nebulæ pluuio&longs;æ, &longs;cilicèt aqua grauidæ, quàm aggregatum ex innumeris granulis minuti&longs;&longs;i­mis aqueis? & cùm prædicta nebula in alti&longs;&longs;imis ae­ris partibus innatat, vellenti&longs;&longs;imo

motu aquæ particulæ eius de&longs;cen­dunt, procùl dubio &longs;uo pondere na­turali augent aeris grauitatem, ideo­que maiori ni&longs;u globum terraqueum comprimunt, quam aer purus, & aqueis guttulis omninò priuatus con&longs;tringere eum po&longs;&longs;it: & ideò fi­&longs;tula mercurialis ABC in infimo prædicto aere con&longs;tituta compri­mitur nedùm à pondere &longs;uper&longs;tan­tis aeris, &longs;ed præterea à ponder&etail; totius aquæ nebulam &longs;uprema&mtail; componentis: itaque per aliquod tempus antequam pluuia de&longs;cendat, fieri pote&longs;t vt mercurius in fi&longs;tula &longs;upremam illam altitudinem M pertingat, in caque permaneat, & hoc nedum à nebulis, &longs;ed à quacum­que alia cau&longs;a grauitante effici pote&longs;t, &longs;i enim terre­&longs;tris puluis à vento, vel alia commotion e &longs;ursùm im­pellatur, atque per aerem di&longs;&longs;ipetur &longs;pargaturque tunc nemo dubitat aerem grauiori ni&longs;u &longs;uperficiem orbis terraquei comprimere. Si po&longs;tea à qualibet cau&longs;a nebula impellatur, vt nimirùm terram attin­gat, &longs;cilic èt pluuia paulatim terram a&longs;&longs;e quatur ean­que humectet, tunc patet innumera aquæ granul&atail; terræ innici, neque amplius aeris grauitatem, & compre&longs;&longs;ionem augere, & quia à terra &longs;ubiecta &longs;u­&longs;tentantur, non po&longs;&longs;unt vt priùs &longs;uo|naturali pondere comprimere &longs;uperficiem infimam mercurij &longs;tagnan­tis, & propterea &longs;emper à minori pondere mercu­rius in C comprimitur prout magis pluuia ad terram perducitur, & prout magis aer illo pondere alleuia­tur, & propterea &longs;uperficies eius in &longs;uprema fi&longs;tulæ parte &longs;en&longs;im deprimitur v&longs;que ad infimum &longs;itum F.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Non tamen conuer&longs;a re­gula vera est nam ab alijs cau&longs;is eleua­tio mercurij in fi&longs;tula va­riari pote&longs;t.

Licèt hoc verum &longs;it, non tamen indè elici pote&longs;t conuer&longs;a regula generalis, vt nimirum quotie&longs;cum­que mercurius in fi&longs;tula eleuatur debeat pluuia ex­pectari, quando quidem pote&longs;t huiu&longs;modi augmentum compre&longs;&longs;ionis produci ab aliqua ingenti agitatione &longs;upremæ atmo&longs;phæræ; & &longs;i fortè à particulis aqueis, & terreis &longs;ubleuatis maior grauitas aeris producitur fieri pote&longs;t vt à violentia ventorum alibi tran&longs;por­tentur nebulæ, & &longs;ic pluuia alibi translata non deci-

dat in eo loco vbi originem habuit. Arque ex his om­nibus concludi pote&longs;t aeremreuera &longs;uo pondere, & vi ela&longs;tica comprimere mercurium in fi&longs;tula conten­tum, eumque ad illam determinatam altitudinem ele­uare.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXVI.

Aerem e&longs;&longs;e grauem experimentis aliorum comprobatur, & primam Mer&longs;ennij experientiam ope ignis infide­lem e&longs;&longs;e.

SEd multò magis patebit veritas prædictæ propo­&longs;itionis adhibitis experimentis à quibus imme­diatè, & directè o&longs;tenditur aeris grauitas, & primò con&longs;tat experientia relata ab Ari&longs;totele, vbi ait, vtrem inflatum maiorem grauitatem, & pre&longs;&longs;ionem exerce­re quàm vacuum. hocque po&longs;tea diligenti&longs;&longs;imè ab alijs comprobatum e&longs;t, & &longs;umma facilitate perfici pote&longs;t non quidem follibus violenter in&longs;ufflando vtrem, &longs;ed leni plenitudine vtre clau&longs;o, vel commodiùs pila lu­&longs;oria aerea ad trutinam examinata, & po&longs;tea funicu­lo circa vtrem, vel pilam reuoluto violenterque con­&longs;tricto, tune quidem ob aeris conden&longs;ationem pon­dus vtris, aut pilæ manife&longs;tè ad trutinam augetur; præterea, vt docuit Galilæus, intra vitream lagenam violentèr aer in&longs;ufflari pote&longs;t vt valdè conden&longs;etur, & tunc pondus prædictæ lagenæ &longs;en&longs;ibilitèr augetur promen&longs;ura aeris ibidem conden&longs;ati, & hac experien­tia diligenti&longs;&longs;imè facta ingenio &longs;i&longs;&longs;imus Antonius Oli-uareperit, quòd grauitas molis aeris, quæ æqualis &longs;it cubo aqueo vnius libræ granum vnum pendet. at Mer&longs;ennus in Ph&ecedil;nomenis pneumaticis opeignis ean­dem experientiam fecit, &longs;ump&longs;it æolo pilam æream, eamque vehementi&longs;&longs;imo igne calefecit, vt prorsùs cande&longs;ceret, & &longs;ic in bilance per&longs;ecti&longs;&longs;ima, quæ à &longs;e­migraro &longs;lecte batur, examinauit pondus eiu&longs;de&mtail; &ecedil;olopilæ candentis, eamque reperit vnciarum 4. drach. 6. & gran. 15. po&longs;tea refrigerata æolo pila eius pon­dus præcedentem &longs;uperauit gran. 4. & hinc elicit ae­rem inclu&longs;um in æolo pila grana 4. pondera&longs;&longs;e, porrò pondus aeris illius ad æqualem aquæ molem ait re­peri&longs;&longs;e in proportione 1. ad 1356.

4. de o cap. 4.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Prop. 29.

Sed prædicta experientia multis nominibus infi­delis e&longs;t, primò quia corpora vehementer excalefacta in bilance &longs;u&longs;pen&longs;a non o&longs;tendunt veram grauitatem eorum, &longs;ed diminutam, quia vt &longs;uperiùs o&longs;ten&longs;u&mtail; e&longs;t, ignis diffu&longs;us ab æolo pila candente valdè rare­facit aerem prædictam æolo pilam ambientem, cum­que aer ambiens fimul cum pila vnum corpus graue componat intra den&longs;iorem aerem &longs;u&longs;pen&longs;um, fit vt aggregatum prædictum minùs graue &longs;pecie &longs;it, quam prius, & proinde imminuitur grauitas æreæ æolo pi­læ, non &longs;olùm ob de&longs;ectum aeris inclu&longs;i, &longs;ed etiam ob eius &longs;eruenti&longs;&longs;imam caliditatem.

c 4 prop. 61.

Rursùs aer in &ecedil;olopila à vehementi&longs;&longs;imo igne am­pliatus expan&longs;u&longs;que non pote&longs;t diciverè rarefactus, quia nimirùm copia ignis vehementi&longs;&longs;imè agitati, & circumuoluti intra æolo pilæ cauitatem di&longs;gregat, ac &longs;e parat particulas aliquas aeris ibidem relictas, ita­que intercapedines, quæ &longs;eparant aeris particulas, partim occupantur ab igne, partim ab inani &longs;patio, dum igneæ particulæ motu veloci&longs;&longs;imo conuertun­tur, & vertigines complent, intercipiendo grandia &longs;patia in ania; vndè malè hinc infertur raritas maxima ad quam aer ampliari pote&longs;t.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXVII.

Secunda Mer&longs;enni experientia in &longs;clopeto pneumatico fact a dubia quoque e&longs;t.

MElior e&longs;t &longs;ecunda Mer&longs;enni experientia dù&mtail; in bombarda, &longs;eu &longs;clopeto pneumatico ma­gno conatu immi&longs;it va&longs;tam aeris molem, quæ in exi­guo &longs;patio conden&longs;ata fuit, aitque pondus &longs;exagin­ta granorum aeris inclu&longs;i&longs;&longs;e in cauitate catapultæ, quæ ab 8. vncijs aquæ impleri poterat, hinc deducit ae­rem in &longs;clopeto immi&longs;&longs;um adeò conden&longs;ari vt quin­decies &longs;patium internum catapultæ expleat; proin­de que tres digitos cubicos aeris ferè ponderare gra­num vnum. Sed ex tanto apparatu tandem Mer&longs;en­nus nil certi colligit, cùm afferat innumeras difficul­tates, & ingenuè fateatur, &longs;emper dubitari po&longs;&longs;e an intra catapultæ cauitatem vnà cum aere in&longs;uffletur particula aliqua oleagino&longs;a, vel aquea, quandoqui­dem epi&longs;tomium emboli humectari debetin eius &longs;u­per&longs;icie coriacea, vt omninò rimæ claudantur, vt re­gre&longs;&longs;us aeris prohibeatur.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Hi&longs;ce omnibus difficultatibus perpen&longs;is plures modi inueniendi aeris grauitatem in Academia Experi­mentali Medicea excogitati fuerunt ab illis doctis vi­ris, hìc tamen referam aliquos ex multis à me ibidem propo&longs;itis.

PROP. CXVIII.

Nouum artificium ad explor andam aeris grauitatem exponitur.

PRimò &longs;umatur fi&longs;tula vitrea

ABCF inflexa propè eius extremum C, in &longs;ummitate verò annexam habeat vitream ampul­lam AB diametro 4. digitoru&mtail;, habeatque duo orificia aperta in M & F, longitudo verò eius BD maior &longs;it &longs;e&longs;qui cubito. Vas præ­dictum hydrargyro impleatur per orificium M, obturato prius o&longs;tio infimo F, & po&longs;teà denuò ve&longs;ica &longs;uilla clau&longs;o &longs;upremo orificio M ibidem alligari debet æneum fi­lum gracili&longs;&longs;imum MSN, & aper­to infimo o&longs;tio F, facto vacuo mo re &longs;olito, de&longs;cendet mercurij &longs;u­perficies v&longs;que ad L, po&longs;t qua&mtail; &longs;cilicèt maior pars eius fluxerit ab infimo orificio F, reman&longs;erit que &longs;patium ABL exinanitum, & tunc de-

nuò duplici ve&longs;ica &longs;uilla &longs;trictè alligata claudatur orificium F. Po&longs;teà præparari debet vas profundum PQR aqua plenum v&longs;que ad &longs;ummitatem PR, &longs;itque eius profunditas tanta vt mergi po&longs;&longs;it vniuer&longs;um in­&longs;trumentum MAC, vt tamen eius ba&longs;is C putei fun­dum non attingat; demergatur fi&longs;tula prædicta vitrea vnà cum mercurio contento intra aquam; & &longs;i fortè os &longs;upremum vitri M non demergitur infra aquæ &longs;u­per&longs;iciem PR, exigui anuli æneiotidem vnciæ gra­na pendentes in C, & in &longs;ummitate A apponantur, quou&longs;que vniuer&longs;a machina vitrea fiat proximè mi­nùs grauis &longs;pecie quàm aqua, &longs;cilicèt innatet, & emi­neat &longs;upra aqu&ecedil; libellam PR pars aliqua SN prædi­cti fili ænei vitro annexi, & in S fiat æquilibrium, & quies. Deinde in aere aperiatur &longs;upremum os vitri M, vt &longs;patium inane ABL aere impleatur, remane­bitque reliqua pars fi&longs;tulæ plena hydrargyro, vt priùs, propterea quod operculum in F impedit exitum mer­curio LCF. In hoc &longs;tatu denuò eadem &longs;uilla ve&longs;ic&atail; claudatur arcteque ligetur vitri os &longs;upremum M; & tandem denuò demergatur fi&longs;tula infra libellam aquæ PR. Et quia in hoc ca&longs;u demergitur infra aquæ libel­lam moles conflata ex ij&longs;dem corporibus, &longs;cilicèt ex vitro ACF, ex hydrargyro LCF, & ex ij&longs;dem ve&longs;icis, & filis M & F, & &longs;olummodò de nouo ade&longs;t aer ABL, quo fi&longs;tula priùs care bat; igitur nece&longs;sè e&longs;t, vt pondus totius machinæ NACF maius &longs;it quàm in priori &longs;ta­tu quando &longs;patium ABL vacuum fuerat. Quaproptèr non poterit denuò &longs;ubleuari fi&longs;tula ad eamdem alti-tudinem S, ni&longs;i grauitas eius imminuatur; au&longs;erri igi­tur debent aliqua grana, &longs;eù anuli ænei è collo &longs;i&longs;tulæ AM, vt machina ad æquilibrium cum aqua redigatur, mergaturque denuò v&longs;que ad fitum S; quotigitur gra­na tolluntur à fi&longs;tulæ collo A, tot præcisè men&longs;ura­bunt pondus aeris ABL intra fi&longs;tulam inclu&longs;i.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Multis modis po&longs;tea indagari pote&longs;t proportio ponderis aeris ad aquam, &longs;ed omnium facillimus, & &longs;implex erit &longs;i in aere perfecti&longs;&longs;ima bilance pondere­tur moles aquæ æqualis &longs;patio ABL, & hic compa­retur cum pondere iam inuento aeris eiu&longs;dem molis ABL.

PROP. CXIX.

Po&longs;tea emis&longs;is quæmplurimis termostaticis à me inuentis afferam instrumentum quo pondus ab&longs;olutum aeris in diuer&longs;is locis eleuatis, ac depres&longs;is, & variè temperatis reperiri pote&longs;t.

FIant tres ampullæ, vel ve&longs;icæ vitreæ, vel æneæ, qualis e&longs;t AB, habeantque collum &longs;upremum CA æneum perfecti&longs;&longs;imè contornatum, hoc autem vi&longs;co­&longs;a aliqua materia, ac tenaci vniatur ferrumineturque cum &longs;uprema ampullæ parte; habeat po&longs;tea canalem, &longs;eu colli cauitatem turbinatam conicè, & perfecti&longs;&longs;i­læuigatam, huic verò cauitati adaptari po&longs;&longs;it aliud operculum paritèr æneum, & turbinatum, & exqui­&longs;iti&longs;&longs;imè læuigatum, vt nimirùm nulla rimula rema­neat, & perfecti&longs;&longs;imè claudat orificium fi&longs;tulæ C, vt prohibeat ingre&longs;&longs;um, aut exitum aquæ, vel aeri; tan­dem aptetur tenui&longs;&longs;imum filum æneum CFE, diuisum in particulas æquales, &longs;eu gra­

dus. Po&longs;tea in fundo va&longs;is D in­clud antur granula exigua plum­bi quou&longs;que vniuer&longs;am ampullam CAB deprimant infra aquæ libel­lam PR, ita tamen vt ampull&atail; CB non pertingat ad fundum va­&longs;is Q, &longs;ed innatet, & &longs;ecetur fi­lum æneum CE à libella aquæ PR in aliquo eius puncto inter­medio F. His præparatis debent tres pr&ecedil;dictæ ampullæ tempera­ri in eodem loco, & eodem va&longs;e aqueo, impleantur­que aere eiu&longs;dem cubiculi ad radicem turris, vel mon­tis po&longs;iti, & in hi&longs;ce omnibus notetur &longs;ignum fili F, quod aquæ &longs;uper&longs;iciem tangit, & adhibitis vulgari­bus termometris notetur gradus caliditatis tùm ae­ris cubiculi, tùm aquæ eiu&longs;dem va&longs;is. po&longs;tea duæ am­pullæ tran&longs;portentur vna ad &longs;ummitatem alicuius tur­ris vel montis, reliquare ponatur medio loco inter sun­mitatem, & radicem, &longs;eu ba&longs;im eius, & ibidem ape­riantur, vt raritatem aeris montani acquirant (arti­ficiosè aere temperato &longs;i opus fuerit vt ad eumde&mtail; caliditatis gradum reducantur, quem in cubiculo ha­buerat;) po&longs;tea denuò am pullæ claudantur, atqu&etail; intra idip&longs;um cubiculum a&longs;portentur, & ibidem in­tra aquam deme&longs;æ, appare bunt differentiæ à prim&atail; ampullarum demer&longs;ione, aer enim &longs;upremæ turris, vt minùs grauis altiùs eleuabit &longs;ilum æneum CE, vt nimirùm &longs;upra aquæ libellam emineat portio maior, quàm EF, & ex prædicta comparatione facilè digno­&longs;ci pote&longs;t diuer&longs;itas ponderis aeris, quæ in diuer&longs;is eleuationibus reperitur. Sic etiam reperiri poterunt differentiæ grauitatum aeris diuer&longs;orum locorum, ac Vrbium.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXX.

Tutis&longs;imo, & facillimo experimento elicitur &longs;pecificam aquæ ad aeris grauitatem &longs;e habere, vt 1175. cum 4. &longs;eptimis ad 1.

SEd præcipuus, ac pulcherrimus modus reperien­di aeris grauitatem hic e&longs;t, quem Acade miæ Me­diceæ experimentali anno 1660. communi caui, vnà cum eius demon&longs;tratione,

eumque ibidem eiu&longs;de&mtail; anni &ecedil;&longs;tate ad praxim re­degi: &longs;ump &longs;i plum beam pi­lam cauam BC aere plenam, & vndique clau&longs;am, hanc quidem perfecti&longs;&longs;ima bi­lance in aere ponderaui, po&longs;tea addito pondere F, à quo po&longs;&longs;et pila BC infra aquæ libellam demergi, paritèr eius pondus pr&longs;um in aqua reperi, alligata nimirùm pila non funi-culis, &longs;ed pluribus &longs;etis equinis à quibus eius gra­uitas in aqua non alteratur &longs;altem differentia &longs;en&longs;ibi­li; poterit ergò &longs;umi additamentum ponderis F ac &longs;i augeret cra&longs;&longs;itiem pilæ plumbeæ BC; &longs;it ergo GE pon­dus totius pilæ BACL vnà cum pondere adiuncto F in aere trutinato; GH verò &longs;it pondus eiu&longs;dem ag­gregati BALCF intra aquam examinatum. quia verò, ex Archimede, pondus corporis intra aquam demer&longs;i imminuitur pro quantitate ponderis molis aquæ quæ æqualis &longs;it integro corpori demer&longs;o, igitur differen­tia HE erit pondus molis aquæ PQ, quæ æqualis &longs;it corpori demer&longs;o BALCF. po&longs;tea pilam plumbeam BC eodem modo clau&longs;am violentèr malleo contudi, vt ad minus &longs;patium BLC redigeretur; manife&longs;tum e&longs;t con&longs;ti patum re&longs;trictumque &longs;ui&longs;&longs;e aerem inclu&longs;um vt nimirùm portio aeris A inclu&longs;a &longs;it in eodem &longs;pa­tio, quod occupabat reliqua aeris portio L. denuò igitur pilam plumbeam contu&longs;am BLCF ponderaui in aere, & in aqua, atque in aere pondus eius fuit GN maius, quàm GE, eius verò pondus in aqua fuit GM, quaproptèr ponderum differentia MN erit gra­uitas molis aquæ RS quæ æqualis &longs;it corpori demer­&longs;o BLCF, & &longs;ecetur EO æqualis MN. Quia verò aer AL in ip&longs;omet aere eiu&longs;dem grauitatis nil grauitat ob æquilibrium, igitur pondus GE tribui debet plum­bo BCF, cùm verò pila contu&longs;a in aere magis graui­tet pro men&longs;ura nimirùm GN, tunc quoque tota gra­uitas GE plumbo eidem tribui debet, at exce&longs;&longs;us grauitatis EN nullo pacto tribui pote&longs;t portioni ae-reæ L, quæ priùs æquè rara erat cum &longs;uo ambient&etail;, &longs;ed tribui de bet portioni aereæ A, quæ in&longs;inuata e&longs;t in eodem &longs;patio L, in quo reliqua pars aeris contine­batur; Po&longs;tea quia HE e&longs;t pondus molis aquæ PQ, quæ &ecedil;qualis e&longs;t moli BA
LCF, & EO e&longs;t pondus mo­lis aquæ RS æqualis inte­græ pilæ contu&longs;æ BLCF; i­gitur differentiale pondus HO pertinet ad aquam VX, nempè ad differentiam aqu&ecedil; PQ &longs;upra RS, qu&ecedil; æqualis e&longs;t aeri A in&longs;inuato intra &longs;pa­tium L; igitur habemus duo corpora inter &longs;e æqualia mole nempè aqua VX, & aer A, horum autem pondera ab&longs;oluta, ex Archimed&etail;, eamdem proportionem habent, quam eorum gra­uitates in &longs;pecie; igitur pondus HO ad OM &longs;iu&etail; ad ei æquale EN, eamdem proportionem habet, quam grauitas in &longs;pecie ip&longs;ius aquæ ad grauitatem &longs;peci fi­cam aeris, reperta autem fuit EN grauitas molis ae­ris A ob contu&longs;ionem in&longs;inuati intra L, igitur nece&longs;­&longs;ariò pondus HO tribui debet aqueæ moli VX. &longs;i po­&longs;tea &longs;umatur moles aquæ Y ad quam aquæ moles VX eamdem proportionem habeat, quam HO ad OM, patet eamdem grauitatem habere aquam Y ac aer A. His demon&longs;tratis referam iam experimentum factum in no&longs;tra Academia experimentali Medicea; pon­dus in aere totius pilæ, & aeris BALCF fuit GE gra-norum 31616. pondus verò eiu&longs;dem in aqua fuit GH gran. 4272, eorum differentia HE fuit gran. 27344. Præterea pondus totius pilæ contu&longs;æ GN fuit gra­norum 31623. in aere, in aqua verò fuit GM gran. 12508, ergò eorum differentia &longs;cilicèt pondus MN, vel EO fuit granorum 19115. pondus EN differen­tiale inter GE, & GN fuit gran. 7. pondus verò dif­ferentiale HO eritgranorum 8229. quare ex regula aurea vt pondus aeris granor. 7. ad pondus molis a­quæ ei æqualis gran. 8229. ita &longs;e habet 1. ad 1175. cum 4. &longs;ept. itaque vna particula aquæ æquè ponde­rabit, ac æ&longs;tiui aeris particulæ 1175. cum 4. &longs;ept. quarum &longs;ingulæ æquales &longs;int mole ip&longs;i aquæ.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

De in&longs;idibus humi­do l. 1. pr. 7.

Cap. 5. de ae­ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Ibide.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Et in hac operatione facillima, quæ fallacijs, ac difficultatibus minimè obnoxia e&longs;&longs;e videtur, &longs;ummo compendionedùm grauitas ip&longs;ius aeris, &longs;ed etia&mtail; proportio, quam habet ad aquæ grauitatem vnic&atail; operatione elicitur.

PROP. CXXI.

Distantia inter maximam aeris con&longs;trictionem, & eiu&longs;dem maximam dilatationem est vt 1. ad 2000. ferè.

TAndem ex no&longs;tris experimentis deducitur ma­xima aeris dilatatio. Suppo&longs;ito enim quòd in catapulta pneumatica aer ad decimam &longs;patij eius par­tem redigatur, quia &longs;upra, ex no&longs;tro experimento, de­duximus aerem rarefieri vt &longs;patium expleat centies, & octuagies maius, quàm priùs, quia verò hic aer communis &longs;tringi conden&longs;arique pote&longs;t violenter v&longs;­que ad decimam eius partem, vel decimam quintam. igitur di&longs;tantia inter maximam aeris den&longs;itatem, & ampli&longs;&longs;imam eius expan&longs;ionem, aut erit 1800. aut 2700. eadem proximè, quæ à Mer&longs;enno po&longs;ita fuerat.

Prop. 105.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXXII.

Aer in naturali eius con&longs;trictione remota omni violentiraris&longs;imus e&longs;t, & &longs;patium occupat bis millies maius quam in &longs;tatu maximæ eius violentæ constri­ctionis, quæ &longs;i remoueatur &longs;pontè, & in­genti vi ad pristinam natiuam rari­tatem redigitur.

QVia verò experientia con&longs;tat aerem dilatari quidem &longs;ponte &longs;ua, & non &longs;ine impetu, & cele­ritate maxima, & è contrà numquam &longs;ponte con&longs;trin­gi conden&longs;arique videmus, &longs;ed &longs;emper hoc efficitur ab aliqua violentia externa, hinc cogimur a&longs;&longs;erer&etail; aerem habere virtutem quamdam ela&longs;ticam, qua ni­mirùm quotie&longs;cumque violentiam con&longs;trictiuam pa­titur, tunc quidem re&longs;ilire vehementerque vibrar&etail; &longs;e&longs;e dilatando po&longs;&longs;e; hoc autem con&longs;tat luculento ex­perimento in ip&longs;a catapulta pneumatica, in qua aer magna vi inclu&longs;us in eius cauitatem po&longs;tea amot&atail; valuula tanta violentia ruit, erumpitque, vt pila&mtail; plumbeam, &longs;eù telum impellat proijciatque, vt i&ntail; magna di&longs;tantia tabulam oppo&longs;itam &longs;atis cra&longs;&longs;a&mtail; di&longs;rumpat, atque terebret: hoc autem nulla ration&etail; fieri po&longs;&longs;et, ni&longs;i aer haberet vim, & facultate&mtail; ingentem &longs;e&longs;e dilatandi, & amplius &longs;patiu&mtail; occupandi. Cùm igitur iam ex &longs;uperiùs dictis inno­tuerit ad quamnam maximam amplitudinem aer ra­refieri, dilatarique po&longs;&longs;it, pariterque ad quem gra­dum con&longs;tipationis, conden&longs;ationi&longs;que comprimi va­leat, & vidimus quòd eadem aeris moles, quæ in &longs;ua maxima conden&longs;atione fuit redacta occupabat minus quam bis mille&longs;imam partem &longs;patij, quod in maxima &longs;ui dilatatione explebat, dicendum e&longs;t aerem in &longs;ua naturali con&longs;titutione, ide&longs;t remota omni violenti&atail; externa, ampli&longs;&longs;imum &longs;patium exigere, & in tali qui­dem expan&longs;ione con&longs;eruari in &longs;uprema aeris regione, vel in &longs;patio vacuo, at in regione infima aeris propè aquam, & terram tunc quidem varijs modis compri­mitur, cùm à pondere aeris incumbentis, tùm à pon­dere aquæ aut terræ in infimis cauitatibus, aut à qua­cumque alia vi motiua ad prædictam maximam con­&longs;tipationem redigitur. Sic videmus in in&longs;trumento Torricelliano aeris granula ad latera mercurij po&longs;i­ta, dum &longs;ursùm a&longs;cendunt quò magis ad mercurij &longs;ummitatem accedunt, eò magis moles aereorum gra­nulorum augeri, quou&longs;que propè &longs;patium inane &longs;u­premum ingentes &longs;ph&ecedil;ras expleant: idip&longs;um immi&longs;&longs;a ve&longs;ica cyprina propemodum exinanita intra mercu­rium ob&longs;eruatur, & clariùs mercurio &longs;uperpo&longs;ita a­quæ portione con&longs;picitur in eodem in&longs;trumento, nam granula aerea intra aquam contenta, quæ hactenùs ob &longs;ui exiguitatem inob&longs;eruabilia, & incon&longs;picua fue­rant, po&longs;tea facto vacuo, &longs;cilicèt &longs;ublata incumbentis aeris compre&longs;&longs;ione, &longs;ubitò con&longs;piciuntur &longs;en&longs;im infla­ri, augerique, vt efficiant ampullas grandes per aquam a&longs;cendentes, quæ ad confinium &longs;upremum eius per­ductæ di&longs;&longs;iliunt, euomuntque aereas particulas intra prædictum &longs;patium inane, cùm è contra &longs;i dum actu eleuantur ampullæ amplæ illæ aereæ, denuò compri­mantur aere &longs;upemè introducto momento con&longs;pi­cies aerem denuò ad &longs;tricti&longs;&longs;imum, & incon&longs;picuum &longs;patium redigi; Non pote&longs;t igitur negari, ni&longs;i negatis euidenti&longs;&longs;imis &longs;en&longs;ationibus, quod naturalis aeris con­&longs;titutio, & di&longs;po&longs;itio &longs;it illa ampli&longs;&longs;ima, & rari&longs;&longs;ima; & præterea quòd quotie&longs;cumque à vi externa compri­mitur, con&longs;tringiturque nihilominùs habeat quoque vim, & energiam naturalem &longs;e&longs;e celerrimè dilatandi, facta nimirum re&longs;ilitione ad modum machinæ.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXXIII.

Aer videtur compo&longs;itus ex machinulis, quæ &longs;tringi quidem adhibita violentia po&longs;sint, &longs;ed postea &longs;ponte re&longs;ilire ad in&longs;tar arcus valeant.

HIc iam quæri pote&longs;t, qualis nam e&longs;&longs;e oporteat aeris &longs;tructura ac forma, vt prædictas opera­tiones efficere valeat. Et profectò &longs;i &longs;en&longs;u, non uerò phanta&longs;ticis, & chimericis hypothe&longs;ibus philo&longs;o­phandum e&longs;t, confiteri tenemur aerem componi ex machinis flexibilibus, & re&longs;ilientibus ad modum ar-cus, quia nimirum in hi&longs;ce machinis prædictum &longs;ymp­toma ob&longs;eruatur, &longs;cilicèt arcus, vel machinæ exigunt amplam illam exten&longs;ionem, & &longs;i ab externa vi con­&longs;tringantur, comprimanturque, tunc &longs;ponte &longs;ua re&longs;ili­unt prioremque amplam &longs;ituationemrepetunt; &longs;i enim aereæ particulæ non e&longs;&longs;ent machinæ profectò percipi non po&longs;&longs;et quare, & quomodò po&longs;t compre&longs;&longs;ionem re­&longs;ilirent; nampo&longs;tquam aeris particulæ compre&longs;&longs;æ &longs;unt, loca non minora, &longs;ed &longs;ibi ip&longs;is ad&ecedil;quata occupant, cum non po&longs;&longs;int corpora &longs;e mutuò penetrare, igitur i&ntail; pr&ecedil;dicta con&longs;trictione libenter per&longs;i&longs;tere deberent, nec qu&ecedil;rerent loca ampliora, quæ ab ip&longs;is impleri oc­cupariquè non po&longs;&longs;ent: deberet igitur ip&longs;is a&longs;&longs;ignari vis quædam motiua quæ di&longs;&longs;ociaret &longs;epararetque ae­ris particulas à &longs;e inuicem, hæc verò &longs;en&longs;u, & cogni­tione quadam anima&longs;tica percipere deberent damnum quod ad con&longs;tipationem con&longs;equeretur, &longs;i enim noxam non perciperent, qua quæ&longs;o ratione &longs;e excitarent ad ope­randum? Quanto rationabilius e&longs;t eam &longs;tructuram ae­reis particulis a&longs;&longs;ignare, à qua nece&longs;&longs;itate cæca cogan­tur &longs;e&longs;e explicare quotie&longs;cumque contra earum natu­ralem exigentiam con&longs;tringuntur; hoc autem a&longs;&longs;e que­mur &longs;i concipiamus aeream &longs;ub&longs;tantiam conflari ex innumeris machinulis iuxtà &longs;e po&longs;itis, & tunc quidem clarè percipiemus in prædicto aggregato virtute mil­lam elateriam reperiri po&longs;&longs;e, quia nimirùm machinu­læ illæ po&longs;t compre&longs;&longs;ionem &longs;e&longs;e conantur dilatare. vt verò con&longs;tet, me non &longs;ubitò nec o&longs;citanter huic &longs;en­tentiæ a&longs;&longs;en&longs;um pr&ecedil;bui&longs;&longs;e, referam quicquid in mentem venit circa aeris &longs;tructuram.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXXIV.

Si aeris minimæ particulæ e&longs;&longs;ent coni excauati magnetica virtute affecti, &longs;aluari po&longs;&longs;ent symptomatæ conden&longs;a­tionis violentæ, & &longs;pontaneæ eius ingentis rarefactionis.

PRimò enim excogitaui artificium, quo &longs;uppo&longs;i­tis aereis minimis particulis non flexibilibus, po&longs;&longs;et nihilominùs fieri prædicta aeris &longs;pontanea di­latatio. Supponebam enim minimas aeris particulas e&longs;&longs;e conicas, &longs;ed excauatas: tunc quidem, cum vertex vnius aerei coni po&longs;&longs;it intra cauitatem alterius in&longs;inuari, po­te&longs;t planè &longs;aluari illa compre&longs;&longs;io, quæ videtur incon­prehen&longs;ibilis aliquibus Philo&longs;ophis, quia enim pars &longs;olida corporea, & plena prædictorum conorum po­te&longs;t e&longs;&longs;e nedùm pars bis mille&longs;ima, &longs;ed adhùc minor &longs;patio inani intra prædictos conos contento, nil enim vetat corpus den&longs;um, ac durum in gracili&longs;&longs;imas lami­nas extendi po&longs;&longs;e, à quibus coni excauati efformen­tur. &longs;ed hic iam nodus difficillim&ecedil; &longs;olutionis &longs;e offert, qua, inquam ratione po&longs;tquàm vnus

conus intrà alium in&longs;inuatus e&longs;t, vim facit &longs;e ab eo &longs;eparandi, procùl du­bio ijs vis qu&ecedil;dam motiua a&longs;&longs;igna­ri debet, & hæc diuer&longs;a non erit ab ea, quæ in alijs corporibus terre­nis reperitur: concipiantur ergo conuli excauati aerei ABC, DCE, FGH, IHL. & &longs;ic alij innumeri eodem modo di&longs;po&longs;iti: animaduerti po&longs;tea, quòd in ma­gnete, & in omnibus magneticis corporibus dantur duo poli, borealis nempè, & au&longs;tralis, & quotie&longs;­cumque duo corpora magnetica &longs;uper aquam inna­tantia ad &longs;e&longs;e propiùs accedunt, tunc quidem polo vnius au&longs;trali vnitur, connectitur que alterius corpo­ris borealis polus, & &longs;i contingat vt alitèr di&longs;ponan­tur à violentia aliqua externa, fponte &longs;ua recedunt, & indebita con&longs;titutione &longs;ituantur, tum re&longs;pectu &longs;ui, cum re&longs;pectu poli au&longs;tralis Orbis Terræ. cogitaia&mtail; conos excauatos ABC, FGH e&longs;&longs;e magneticos, vel ferreos virtute tamen magnetica affectos, vt nimirùm omnes vertices A, & F &longs;int poli boreales, partes ve­rò au&longs;trales &longs;int ba&longs;es BC, & GH, & quia ba&longs;es præ­dictæ &longs;unt cauæ poli au&longs;trales præcisè exi&longs;tent in cen­tris circulorum BC, & GH. his po&longs;itis innatent iam pr&ecedil;dicti conuli, &longs;cilicèt mouerilateralitèr po&longs;&longs;int ab&longs;­que vllo impedimento, tunc quidem polus borealis F coni FGH, &longs;i coniungi debet iuxtà magneticas le­ges cum polo au&longs;trali conuli ABC nece&longs;&longs;ariò vertex F cum centro circuli ba&longs;is BC coniungetur naturali in&longs;tinctu, & ideò re&longs;i&longs;tet externæ violentiæ, quæ hanc fituationem perturbare conaretur. A dueniat iam alia vis externa, quæ violentèr in&longs;inuet verticem F intra finuo&longs;am cauitatem alterius versùs A, tunc quide&mtail; naturali ni&longs;u, ce&longs;&longs;ante violentia externa, recedet ver­tex coni FGH ab interna illa po&longs;itione, & denuò re­trocedet quou&longs;que eius vertex F coniungatur centro circuli ba&longs;is BC. Et hæc inquam e&longs;&longs;et vis ela&longs;tica, quæ in aere reperitur, nec talis hypothe&longs;is vt impo&longs;&longs;ibilis reprobari po&longs;&longs;et, cum reuera & terra, & corpora om­nia terrena magneticam vim habere manife&longs;tum &longs;it, in quibus prædicta operatio nece&longs;&longs;ariò &longs;equeretur, po&longs;ita nimirum prædicta figuratione in particulis ma­gneticis. Po&longs;&longs;ent aliunde omnia alia phænomen&atail;, quæ in aere ob&longs;eruantur &longs;aluari ex prædicta hypo­the&longs;i, igitur concediea deberet &longs;altem vt po&longs;&longs;ibilis.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

PROP. CXXV.

Meliùs aeris proprietates &longs;aluantur &longs;i eius minimæ particu­læ &longs;int duræ flexibiles, & re&longs;ilientes ad modum ma­chinæ, habeantque figuram tubi, vel cylindri excauaticompo&longs;iti ex laminis, vel filis læuibus, aut ramo&longs;is obliquè in &longs;e ip&longs;os circumductis.

HAnc tamen hypothe&longs;im po&longs;tea reiecire accura­tiùs con&longs;iderata; &longs;nppo&longs;ui enim tubulos ali­quos gracili&longs;&longs;imos multis modis componi po&longs;&longs;e ex materia re&longs;iliente ad modum machinæ. Primò &longs;uppo­ni po&longs;&longs;unt tubuli conflati ex tenui&longs;&longs;ima laminula i&ntail; &longs;e ip&longs;am circumducta, & continuata, quæ paritèr machina &longs;it flexibilis, & po&longs;t compre&longs;&longs;ionem re&longs;ilire valeat, vt contingit in arcu compre&longs;&longs;o. hinc &longs;aluari pote&longs;t maxima illa aeris conden&longs;atio quam patitur à vi externa comprimente, quia nimirùm perimetrum internum fi&longs;tulæ licèt &longs;emper eiu&longs;dem men&longs;uræ &longs;it, tamen minorem capacitatem continentèr acquirit, quò magis comprimitur, &longs;cilicèt quò magis à circu­lo recedit eius ba&longs;is, & ad figuram longiorem ellip­ticam redigitur. Alio modo componi po&longs;&longs;unt tubuli aerei, &longs;i nimirùm concipiatur inuolucrum factum ex lamina tenui&longs;&longs;ima, quæ quidem paritèr flexibilis &longs;it, & ad modum arcus re&longs;ilire valeat, hæc, inquam, mul­tò magis comprimi pote&longs;t, & ad minus &longs;patium redi­gi, quam &longs;implex tubus paulò ante expo&longs;itus, qui&atail; nimirùm internus ambitus adhùc con&longs;tringi, & immi­nui pote&longs;t, vt nimirùm perimeter ba&longs;is minor fiat, re­petitis nimirum conuolutionibus prædicti inuolucri, & præterea, non minùs, quam antea pote&longs;t laterali­tèr comprimi vt nimirùm ba&longs;is non circularis, &longs;ed el­liptica fiat, & &longs;ic duplicata cau&longs;a re&longs;trictionis mul­tò magis minui poterit moles aeris con&longs;tipati con­den&longs;atique; Tertiò &longs;i &longs;upponantur tubuli aerei com­po&longs;iti ex tenui&longs;&longs;ima virga ramo&longs;a, vel fa&longs;cia obliquè reuoluta, & in &longs;e ip&longs;am circumducta ad modum &longs;pi­ræ, relictis nimirùm aliquibus inter&longs;titijs inter tran&longs;­uer&longs;ales &longs;piras, tunc quidem multò faciliùs tubulus prædictus con&longs;tipari poterit tribus nominibus, & quia ambitus internus imminuitur, pariterque decur­tatur altitudo fi&longs;tulæ, & tandem ad figuram compre&longs;­&longs;am ellipticam redigitur, quare &longs;i &longs;olida materia præ­dicti tubuli, &longs;eù &longs;piræ &longs;it dura quidem, &longs;ed flexibilis, & apta ad re&longs;iliendum vt machina, vel arcus chali­beus, eique naturalitèr competat ampla, & dilatat&atail; &longs;igura, poterunt profectò con&longs;tringi ab externa vi, at ce&longs;&longs;ante violentia &longs;ponte &longs;ua re&longs;ilient, ad prioremque &longs;tatum dilatatum, rarumque redigentur, vt videmus in ijs &longs;erpentibus puerorum ex tenui&longs;&longs;imo æneo filo confectis, &longs;cilicèt &longs;piralitèr reuolutis ad modum co­chleæ, in ij&longs;que facta compre&longs;&longs;ione &longs;patium eorum ma­ximè imminuitur, at po&longs;tmodum raritatem &longs;uam de­nuò repetunt. Et hac quidem figura a&longs;&longs;ignata aeri fa­cilè &longs;aluantur phænomena omnia, quæ in ip&longs;o aer&etail; ob&longs;eruantur, de quibus &longs;igillatim &longs;uis in locis pecu­liaritèr agemus.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Cap. 5. de ae ris grauitate æquilibrio, &longs;tructura, & vi elateri&atail; eius.

Nullam Attractionem, nec Vim Tractiuam in Natura dari.

CAP. VI.

NIl frequentiùs apud Medicos, & Philo&longs;ophos reperitur, quàm nomen qualitatis, &longs;eu virtu­tis attractiuæ, quæ licèt magno fa&longs;tu, & &longs;upercilio proferatur, nil profectò ab&longs;urdiùs reperies, &longs;i attentè perpendas quid nomine attractionis intelligant. Aiunt igitur manife&longs;tè con&longs;tare in natura attractionem da­ri, vt videre e&longs;t in magnete, qui ferrum ad &longs;e trahit, pariterque electrica omnia corpora fe&longs;tucas exiguas magno impetu ad &longs;e adducunt, &longs;ic paritèr calorem, & dolorem in aliqua determinata parte animalis ex­citatum, vt in manu v. g. vel crure, attrahere à parti­bus longinquis nedùm &longs;anguinem, &longs;ed etiam humo­res cæteros aiunt; non &longs;ecùs cucurbitulæ medicæ fol­les, & alia in&longs;trumenta pneumatica dum aerem exu­gunt, attrahunt quoque humores adnexos; quia ve-rò in hi&longs;ce omnibus operationibus nullum organum corporeum apparet à quo tractio effici valeat; hinc concludunt vim, & qualitatem attractiuam incor­poream e&longs;&longs;e, habereque facultatem ad &longs;e attrahendi fluida corpora ambientia. Sed quis capiet à virtut&etail; incorporea naturali vi, & immediatè, ab&longs;que organo corporeo, corpus aliquod moueri, & trahi po&longs;&longs;e? quo­modo enim quod incorporeum, & proindè indiui&longs;i­bile e&longs;t applicare &longs;e pote&longs;t, apprehendere, con&longs;trin­gere, impellereque corpus exten&longs;ionem habens, cum lumine naturæ con&longs;tet nullam motionem, aut actio­nem phy&longs;icam ab&longs;que contactu fieri po&longs;&longs;e, pariter­que con&longs;tet corpus ab incorporeo minimè tangi? Igi­tur nece&longs;sè e&longs;t vt attractio fiat mediante aliquo in­&longs;trumento corporeo.

Cap. 6. non dari attracti­onem.

PROP. CXXVI.

Agens naturale ni&longs;i moueatur minimè trahere pote&longs;t aliud corpus, quod præterea fune, vel vncino alligatum transferri debet.

QVia agens corporeum quotie&longs;cumque &longs;ua vi mo­tiua trahit aliud corpus nece&longs;&longs;ariò agitari quodammodo, & moueri debet &longs;i enim omninò iners, & &longs;tabile agens &longs;upponatur, quomodò quæ&longs;o aliud corpus contiguum agitabit, & è &longs;uo loco dimouebit? verùm quando agens motu locali agitatur, tunc com­prehendo, quòd corpus ei adnexum è regione po&longs;i­tum expelli è &longs;uo loco debet, aliàs agens corpus non moueretur; & hoc con&longs;tat quia duo corpora &longs;e mutuò penetrare non po&longs;&longs;unt: igitur &longs;i obiectum corpus &longs;lui­dum fuerit, &longs;altem agitari debet lateralitèr vt liberum tran&longs;itum impellenti corpori concedat, & &longs;i fuerit durum, ac con&longs;i&longs;tens, integrum corpus obiectum di­mouebit id expellendo. Si verò corpus ambiens non anteriùs motui eius obijciatur nec ip&longs;um impe­diat, &longs;ed po&longs;ticè ei adhæreat, tunc quidem &longs;i allige­tur fune, vel vncino, alioque con&longs;imili corpore cur­uo, fieri pote&longs;t, vt ad motum agentis etiam colligatum corpus &longs;ub&longs;equens transferatur. Et hoc quidem ea­dem ratione lumine naturæ deducta euincitur, quia in&longs;trumenti tractorij pars curua, quæ anteriùs impel­litur ab agente, ob eandem impenetrabilitatem an­teriùs impellitur, & ab eius duritie, & &longs;oliditate cor­pus po&longs;ticè apprehen&longs;um transfertur; at &longs;i funis, aut vncinus, vel quodlibet aliud organum curuum re­moueatur, non video, neque percipio quomodo dum mouetur corpus anticum trahere &longs;ecum debeat cor­pus po&longs;ticum nullo vinculo, nec glutine &longs;ibi connexum.

Cap. 6. non dari attracti­onem.

Sed non de&longs;unt Philo&longs;ophi, qui dicant: æquè faci­lè concipi corpus ten&longs;um dum &longs;e&longs;e reducit, aliud corpus, cui contiguum est &longs;ecum adducere, ac corpus compre&longs;&longs;um aliud corpus à&longs;e amouere, nec alio fune opus e&longs;t ad hunc finem, cùm enim iuxtà naturæ in&longs;titutum omnia corpora &longs;int par­tes vniuer&longs;i, & partes, quætotum aliquod componunt con­iunctæ eße debeant, alioquin partes non e&longs;&longs;ent &longs;i &longs;eor&longs;im e&longs;&longs;e po&longs;&longs;ent, ideò vnum corpus adhæret alteri.

Cap. 6. non dari attracti­onem.

PROP. CXXVII.

Primò dico fal&longs;um e&longs;&longs;e æquè facilè corpus ten&longs;um dum &longs;e re­ducit aliud corpus cui contiguum e&longs;t &longs;ecum adducere, ac corpus compre&longs;&longs;um aliud corpus à &longs;e amouere.

QVia nece&longs;&longs;itas huius operationis patet ex eo quòd corpus moueri non pote&longs;t ad locum al­terius corporis occupandum, ni&longs;i expellat illud ibi degens, cùm duo corpora in eodem loco poni no&ntail; po&longs;&longs;int; atquod corpus dum mouetur recedendo ab alterius corporis locotrahere &longs;ecum adhærendo de­beat corpus po&longs;ticè &longs;ibi contiguum à cuius contactu conatur recedere, & cui non colligatur glutine, fu­ne, aut alio vinculo, nedùm gratis a&longs;&longs;eritur, verum om­ninò impo&longs;&longs;ibile videtur, & omnem captum &longs;uperat. Cùm verò ait naturæ in&longs;titutum e&longs;&longs;e vt corpora mundana &longs;int partes vniuer&longs;i hoc planè ei conceditur, &longs;ed nego, quòd partes, quæ totum componunt, coniunctæ e&longs;&longs;e debeant, & quod aliàs partes non e&longs;&longs;ent &longs;i &longs;eor&longs;im e&longs;&longs;e po&longs;&longs;ent; nam partes exercitus di&longs;cretæ &longs;unt, & tamen totum exer­citum componunt. Similiter plures lineol&ecedil; di&longs;cretæ totam longitudinem palmarem componere po&longs;&longs;ent, non &longs;ecùs ac &longs;i coniunctæ directæ, vel tortuo&longs;æ e&longs;&longs;ent. Et noto, quòd nomine coniunctionis hìc non intelli­gitur vnio, & connexio omninò firma, &longs;ed &longs;implex contactus partium, qualis e&longs;t ille quo aceruus arenæ, & granorum tritici connectitur; nam aqua à contiguo aere attracta, vel ab embolo eis non connectitur vni­turque, &longs;ed tantum adhæret &longs;implici contactu. Modò nemo e&longs;t, &longs;i &longs;eriò, & bona fide loqui velit, qui no&ntail; percipiat e&longs;&longs;e impo&longs;&longs;ibile vt grana tritici &longs;ub&longs;equen­tia trahantur ab antecedentibus granis, eorumqu&etail; motum imitentur à vi &longs;implicis contactus ab&longs;que vl­lo vinculo, vel glutine, & procùl dubio talis motus effici po&longs;&longs;et quando grana &longs;ub&longs;equentia ab aliqu&atail; vimotiua impellerentur, qu&ecedil; aut &longs;pontaneo motu, co­gnitione præuia, vt animalia, aut cæca nece&longs;&longs;itate, vt grauia, tran&longs;portarentur, quæ omnia in no&longs;tro ca­&longs;u locum non habent.

Cap. 6. non dari attracti­onem.

Sed ne gratis prolata verba diutiùs in&longs;ectemur, noto quòd aduer&longs;arij numquam euincent dari in na­tura vim, &longs;eu qualitatem attractiuam, ni&longs;i euidentia &longs;en&longs;us, aut demon&longs;tratione o&longs;tendant, quòd corpo­ra, quæ attrahi videntur non moueantur à vi intrin&longs;e­ca &longs;pontaneo motu, neque impellantur ab externo a­liquo corpore. Hoc autem cùm numquam præ&longs;tite­rint, profectò affirmare non po&longs;&longs;unt dari in natura ve­ram attractionem, proindeque licitum erit eorum a&longs;­&longs;ertionem negare.

E contrà &longs;i nos offenderimus, quòd aliqua corpo­ra eorum, quæ attrahi videntur vi naturali, &longs;ponte mo­ueantur, & accedant ad alia corpora: reliqua verò vi externa impellantur, planè profligata erit vis, & qua­litas attractiua è rerum natura.

Cap. 6. non dari attracti­onem.

PROP. CXXVIII.

Corpora, quæ attrabi videntur, aut &longs;ponte, aut à vi ex­terna impelluntur.

Cap. 25.

ET primò quoad ferrum, & magnetem pertinet, iam o&longs;tendimus (lib. de vi percu&longs;s.) ambo hæc corpora naturali vi &longs;pontaneo motu vnum versùs al­terum moueri non &longs;ecùs, ac grania &longs;ponte ad terram feruntur. In electricis verò iam ab alijs cau&longs;a attra­ctionis tradita e&longs;t; con&longs;tat enim experientia, quod ni&longs;i electrica corpora incale&longs;cant ope confricationis in aliquo panno factæ non attrahunt exiguas, & leues ei&longs;que vicinas fe&longs;tucas, quæ proindè collocantur in quadam veluti at mo&longs;phæra ex fumo&longs;is, & calidis ex­halationibus compo&longs;ita ambiente corpus electricum, ex quo fit vt ma&longs;&longs;a illa ex prædictis vaporibus, & fe­&longs;tucis compo&longs;ita leuior &longs;it aere contiguo magis re­moto, ideoque ab hoc ma&longs;&longs;a illa fumo&longs;a exprimitur, con&longs;tringiturque vndique versùs &longs;olidum corpus ele­ctricum, & con&longs;equentèr &longs;ecum tran&longs;portabit fe&longs;tucas.

In tubis pneumaticis, & cte&longs;ibianis, nec non in cu­cur bitulis medicis, dicendum, quòd ad eas fluida, & mollia corpora feruntur non &longs;pontaneo motu, &longs;ed à vi externa impul&longs;a, & hæc profectò non e&longs;t alia quà&mtail; &longs;implex grauitas oceani aerei orbem terraqueum am­bientis, à quo aqua, & corpora mollia &longs;ubiecta con­primuntur, exprimunturque, vt con&longs;tat ex doctrin&atail; hydro&longs;tatica &longs;uperiùs expo&longs;ita. Hinc fit vt &longs;ubleua-

to embolo in tubo, vel rarefacto aere interno cucur­bitulæ pars fluida, & mollis &longs;ubiecta minùs compre&longs;­&longs;a ab ambiente aere expelli &longs;ursùm debeat à part&etail; magis pre&longs;&longs;a. Stultè ergo quis recurreret ad vim, & qualitatem attractiuam emboli, vel cucurbitulæ, vt aquam eleuet, cùm ad&longs;it vera, & nece&longs;&longs;aria cau&longs;a hu­ius effectus, quæ e&longs;t columna aerea aquam &longs;ubiectam comprimens, à qua vi impul&longs;iua aqua in&longs;inuatur, ex­primiturque intra tubum, vel cucurbitam.

Cap. 6. non dari attracti­onem.

Cap. 12.

Sed hoc clariùs &longs;uo loco declarabitur; interim tran­&longs;eo ad difficultatem &longs;atis plau&longs;ibilem, quæ contra hanc

doctrinam afferri &longs;olet. Inquiunt enim, quando cu­curbitulæ carnem attrahunt, vel fi&longs;tula digiti pulpam intra eam in&longs;inuat, manife&longs;tè percipitur &longs;en&longs;us dolo­rificus in parte illa carnis, aut digiti, quæ intra cucur­bitulam, vel fi&longs;tulam in&longs;inuatur, nulla verò pa&longs;&longs;io, aut noxa percipitur in reliqua parte corporis animalis, nec in po&longs;tica digiti parte, &longs;en&longs;us verò doloris à nihi­lo produci non pote&longs;t, & è contrà cau&longs;a actiua com­pre&longs;&longs;ionem efficiens &longs;en&longs;ationem dolorificam afferre deberet, igitur &longs;en&longs;us doloris percipi deberet non in pulpa digiti, &longs;ed in oppo&longs;ito vngue, pariterque dolor non in &longs;capulis, vbicucurbita idhæret, &longs;ed in pecto­re percipi deberet, vbi reuerà efficitur compre&longs;&longs;io, & contu&longs;io ab extremo aere ambiente, in ip&longs;a verò pulpa carnis intra cucurbitam, vel fi&longs;tulam in&longs;inuata nulla pa&longs;&longs;io percipi deberet, cùm ibi deficiat cau&longs;&atail; illa, quæ &longs;ua violentia impellit, & comprimit carnem.

Saers pre&longs;­&longs;io animalis carnem intra cucurbitulas impelleret dolor in ­pe&longs;ita corpo­ris parte con­pre&longs;&longs;a perci­pi deberet, non in pur­ attracta.

Pro huius difficultatis &longs;olutione repetenda &longs;unt aliqua priùs declarata, vbi &longs;cilicèt quærebatur qua­re vrinatores in profundo maris ingentem grauitatem aquæ incumbentis non percipiunt, diximus hoc pro­uenire, ex eo, quòd partes aquæ fluidæ æquali ni&longs;u grauitatis comprimunt vndequaque corpus anima­lis demer&longs;um, nempè è parte &longs;uprema infima, & col­laterali, quia ibidem o&longs;tendimus, quòd impul&longs;io, at­que compre&longs;&longs;io in vno peculiari loco facta luxatio­nem, rupturam, contu&longs;ionemque efficere pote&longs;t, & è contra &longs;i eadem virtus compre&longs;&longs;iua multiplicetur, vt vndique impellat, comprimatque corpus animalis, tunc o&longs;tendimus nedùm noxam doloremque non au­geri, &longs;ed è contrà nullam luxationem, neque contu­&longs;ionem, & proinde nullam pa&longs;&longs;ionem dolorifica&mtail; procreari po&longs;&longs;e. Et hoc euidenti&longs;&longs;imum e&longs;t ex &longs;upe­riùs demon&longs;tratis. Præterea diximus, quòd licèt in­&longs;ignis luxatio, & diui&longs;io continui ab vniuer&longs;ali ill&atail; compre&longs;&longs;ione fluidi non &longs;ub&longs;equatur, nontamen ne­gari pote&longs;t con&longs;trictio quædam totius corporis, quæ quidem in profundo oceani oportet vt &longs;entiatur, ob nouitatem; at in aere nullo pacto animal ab vniuer­&longs;ali eius compre&longs;&longs;ione con&longs;trictioneque vllam pa&longs;­&longs;ionem percipere debet ob a&longs;&longs;uetudinem, ab ip&longs;o e­nim ortu animalia &longs;emper eadem ve&longs;te aerea ambiun­tur con&longs;tringunturque, proindeque nullam mutatio­nem in ip&longs;o animali aeris compre&longs;&longs;io producit, & propterea cen&longs;et à nulla vi ambiente con&longs;tringi, aut comprimi, igitur à prædicta vi compre&longs;&longs;iua carnes, va&longs;a, & vi&longs;cera patiuntur con&longs;trictionem quamdam, quæ profectò nullo pacto percipi pote&longs;t ab animali­bus. Imò etiam con&longs;trictiones non perpetuæ, vt sunt illæ quæ fiunt à no&longs;tris ve&longs;timentis ob con&longs;uetudinem, pa&longs;&longs;ionem dolorificam minimè afferre &longs;olent.

Cap. 6. non dari attracti­onem.

Cap. 3.

Re&longs;oluitur &longs;uperior dif­ficultas.

Cap. 6 non dari attracti­onem.

PROP. CXXIX.

Ce&longs;&longs;ante in vnaparte aeris compres&longs;ione humores, & mol­lis eaes impelli debent intra cucurbitulam.

HIs præmi&longs;&longs;is animaduertendum e&longs;t, quòd nouus effectus flexionis, aut diui&longs;ionis continui, vel contu&longs;ionis in animali duplici modo produci pote&longs;t, aut quia &longs;uperuenit noua cau&longs;a impellens vnicum ani­malis latus, aut quia deficit ibidem vis illa compre&longs;­&longs;iua fluidi ambientis, quæ reliquas omnes animalis partes con&longs;tringit, comprimitque, & quæ hactenùs ob con&longs;uetudinem non percipiebatur. In primo ca&longs;u mirum non e&longs;t effectum contu&longs;ionis dolori&longs;que tribui impellenti virtuti &longs;uperuenienti; at in &longs;ecundo ca&longs;u fallacia oriri pote&longs;t ex phanta&longs;ia præiudicata, &longs;cili­cèt exi&longs;timabitur defectum comprimentis fluidi i&ntail; vno latere tractionem, & &longs;uctionem procreare, quan­doquidem nemo per&longs;uadebitur, quòd oppo&longs;ita com­pre&longs;&longs;io facta à fluido ambiente, cuius actionem num­quam percepit ob a&longs;&longs;uetudinem, contu&longs;ionem, aut impul&longs;ionem fanguinis, & carnium efficere vnquam potui&longs;&longs;et. Nec de&longs;unt exempla quibus hoc confirma­tur. ponatur Rana infra aquam, vel hydrargyrum de­mer&longs;a, con&longs;tat eam vndique &longs;tringi veluti prælo à flui-do ambiente; &longs;i po&longs;tea foramini collaterali va&longs;is ra­næ abdomen applicetur vt exactè perimetrum fora­minis contingat, tunc portio cutis eius comprehen­&longs;a à prædicto foramine inflari, & turgere con&longs;picie­tur, & veluti mammillam tumidam extra forame&ntail; ad partes aeris exporrigere, non quidem quia attra­hitur ab aere externo, &longs;ed quia exprimitur à pre&longs;&longs;io­ne grauioris fluidi ambientis: verùm cùm prædict&atail; extuberantia creari non po&longs;&longs;it ab&longs;que violenta tra&longs;­po&longs;itione, & di&longs;tractione partium in abdomine con­tentarum, &longs;cilicet inte&longs;tinorum, membranarum, va­&longs;orum, & cutis, igitur hinc &longs;ub&longs;equetur pa&longs;&longs;io dolo­rifica, quam rana iudicabit ab aeris externi attra­ctione factam fui&longs;&longs;e, nec vnquam per&longs;uaderi po&longs;&longs;et à pondere aquæ, vel mercurij ambientis depender&etail;. Non &longs;ecùs vniuer&longs;alis illa aeris compre&longs;&longs;io continua­ta, & a&longs;&longs;idua quadam pre&longs;&longs;ione contu&longs;ioneque corpus vniuer&longs;um animalis veluti prælum &longs;tringit, atque ob con&longs;uetudinem nullam noxam, neque &longs;en&longs;atione&mtail; creat; ce&longs;&longs;ante po&longs;tea in aliqua peculiari corporis parte huiu&longs;modi compre&longs;&longs;ione mirum non e&longs;t &longs;i hu­mores, & carnes ob compre&longs;&longs;ionem factam in reliquis locis animalis impellantur violentèr intra cucurbi­tulam, vbi actio compre&longs;&longs;iua aeris deficit, & ibidem pa&longs;&longs;io dolorifica &longs;entiatur.

Cap. 6. non dari attracti­onem.

Cap. 6. non dari attracti­onem.

PROP. CXXX.

Pluribus experimentis confirmatur à pondere ambientis fluidi corpora mollia intra cucurbitulas, & fistulas in&longs;inuari.

QVòd po&longs;tea reuerà caro intra cucurbitulam in­&longs;inuetur à compre&longs;&longs;ione externi aeris ambien­tis, pote&longs;t pluribus experimentis comprobari. &longs;uma­tur ve&longs;ica &longs;uilla aere plena, &longs;ed non valdè ten&longs;a, eique applicetur orificium cucurbitulæ paritèr aere ple­næ, vt nimirùm perimetrum eius oris tangat ve&longs;icæ pelliculam, pofteà ve&longs;ica cum annexa cucurbitula in­fra aquam demergatur, videbis quò magis ve&longs;ica ad fundum aquæ perducitur, eò magis portionem ve&longs;i­cæ intra cucurbitam contentam turgere inflarique, & intra cucurbitulæ cauitatem aliquantulum in&longs;inuari, perindè, ac caro no&longs;tra turgens intra cucurbitulas immitti &longs;olet. Et multò euidentiùs hoc continget fi prædicta ve&longs;ica aqua impleatur, & po&longs;tmodum vnà cum annexa cucurbitula infra hydrargyrum immitta­tur, videbis quòd tanta vi turgida pars ve&longs;icæ intrà cucurbitulam immittitur, vt requiratur violentia ali­qua ad diuellendam cucucurbitulam ab ip&longs;a ve&longs;ica. Et hoc profectò tribui non pote&longs;t virtuti attractiuæ, quam nec cucurbitula, neque aer inclu&longs;us habet, &longs;ed manife&longs;tè hoc efficitur à pondere aquæ, vel mercurij ambientis, à quo ve&longs;ica vndique comprimitur præ­terquàm in illo circello comprehen&longs;o à cucurbitulæ orificio, ibi enim aer inclu&longs;us in cucurbitula tantum­modò ve&longs;icam tangit, & durities vitreæ cucurbitulæ veluti fornex impedit ne aqua, vel hydrargyrum am­biens &longs;ubiectam ve&longs;icæ particulam comprimat con­tundatque.

Cap. 6. non dari attracti­onem.

Idip&longs;um hoc alio opportuniori experimento com­probari pote&longs;t: in fi&longs;tula vitrea vtrinque aperta aere plena infernè aptata digiti pulpa orificium eius om­ninò claudatur, po&longs;tea manus cum ei annexa, & in­cumbente fi&longs;tula immergatur intra aquam, vel hydrar­gyrum, itaut &longs;upremum fi&longs;tulæ orificium extet &longs;u­pra mercurij, aut aquæ libellam; tunc caro pulpæ di­giti inflatur tumoremque in&longs;inuat rubicundum intr&atail; fi&longs;tulam, percipitur que &longs;en&longs;us quidam &longs;uctionis, & hic con&longs;tat non ade&longs;&longs;e vim vllam attractiuam, cù&mtail; aer intra fi&longs;tulam &longs;upernè reclu&longs;am nullam attractionem faciat, & proindè concedendum e&longs;t, à pondere am­bientis aquæ, vel mercurij, comprimi manum, atque digitum, & &longs;ic &longs;anguinem exprimi in&longs;inuarique in illa parte digiti, quæ non &longs;tringitur, nec comprimitur à pondere ambientis fluidi.

Idem ob&longs;eruabitur, &longs;i homo ad in&longs;ignem profunditatem aquæ demer&longs;us fi&longs;tulam làbijs comprehen&longs;am, & &longs;u­premo aeri communicantem &longs;ecum deferat, vel orifi­cium fi&longs;tulæ cuti manns, aut brachij applicet; is cer­tè videbitlinguam, vel cutim intra fi&longs;tulam parum­per in&longs;inuari, & &longs;en&longs;um &longs;uctionis patietur, ad in&longs;tar eius qui in cucurbitulis fieri &longs;olet.

Idip&longs;um experieris &longs;i ingentem cucurbitulàm ab-domini applicatam tecum deferas in profundo maris. Ex quibus omnibus con&longs;tat, quòd à compre&longs;&longs;ione me­dij fluidi ambientis con&longs;tringuntur partes omnes ani­malis, & proindè exprimi pote&longs;t sanguis, & caro mol­lis in ea cauitate cucurbitæ, in qua cutis caret com­pre&longs;&longs;ione cùm aer cucurbitæ rarefactus ab igne, vel à &longs;uctione, aut emboli tractione &longs;it imminutus, fit vt minimè comprimat cutim &longs;ubiectam, ea validitat&etail;, qua reliquæ animalis partes ab ambiente aere con­tunduntur.

Cap. 6. non dari attracti­onem.

Obijciu&longs;en&longs;u prci­pi |tractionem in parte cor­poris centi­gua cucur­bitulæ, non verò pæti im pul&longs;um à flui do in reli­quo corpofactam.

Sed, dices, &longs;en&longs;u ip&longs;o percipitur tractio quæda&mtail; in cucurbitulis, non verò percipimus impul&longs;ione&mtail; factam à fluido externo comprimente reliquas anima­lis partes à cucurbitula non tactas.

PROP. CXXXI.

In actione cucurbitulæ ex cutis distractione, & ten&longs;ione, &longs;en&longs;us falsò &longs;e percipere &longs;uadetur trahi cutim, & &longs;an­guinem, cum verè tumor fiat à pres&longs;ione am­bientis aeris.

NVllus alius effectus percipitur in cucurbitulis medicis præter quàm violenta quædam ex­pre&longs;&longs;io, & intru&longs;io carnis, & &longs;anguinis intra cucur­bitulæ cauitatem, à qua nimirum pellis vehementer inflatur, & tumet proindeque cutis di&longs;ten&longs;a &longs;en&longs;um doloris patitur. Hoc autem triplici modo fieri po&longs;&longs;e con&longs;tat, aut quia funibus, & vncinis incon&longs;picuis cu­tis, caro, & &longs;anguis trahuntur intra cucurbitulam, aut

quia &longs;pontaneo motu ad replendum vacuum ibidem accurrunt, vel quia ab extrin&longs;eca violentia pre&longs;&longs;io­nis aeris ibidem exprimuntur immittunturque. pri­mus modus videtur omninò ab&longs;urdus, &longs;ecundus reij­citur quoque, nam &longs;i reuerà caro, & &longs;anguis &longs;pont&etail; &longs;ua intra cucurbitulam migrant, ergo ibidem no&ntail; attrahuntur violentèr, proindeque e&longs;t impo&longs;&longs;ibile, vt facultas animalis percipiat &longs;en&longs;um doloris ob violen­tiam quam non patitur, & quæ non exi&longs;tit in natura. Et licèt dici po&longs;&longs;et dolorem creari per accidens ob cutis, & carnis di&longs;tractionem; ex hoc ip&longs;o infertur sen­&longs;itiuæ facultatis fallacia, & deceptio, quilibet enim iuraret fen&longs;u percipere tractionem violentam carnis, non verò motum eius &longs;pontaneum intra cucurbitulam.

Cap. 6. non dari attracti­onem.

Fatendum ergo e&longs;t, tumorem carnis, & &longs;anguinis intra cucurbitulas produci non po&longs;&longs;e ab alia cau&longs;&atail; quàm à pre&longs;&longs;ione aeris ambientis, quæ ex præmi&longs;&longs;is propo&longs;itionibus nece&longs;&longs;ariò prædictum effectum cre­are debet, quatenùs in particula illa carnis intra cu­curbitulam inclu&longs;a deficit vis compre&longs;&longs;iua ambientis aeris, hæc verò cùm minimè percipiatur, nec ad­uertatur ob a&longs;&longs;uetudinem, mirum non e&longs;t, nouum effe­ctum tumoris non tribui cau&longs;æ ignotæ licèt veræ, &longs;ed potiùs tribuatur ei cau&longs;æ licèt &longs;al&longs;æ, quæ ibidem ade&longs;­&longs;e &longs;en&longs;ibus con&longs;tat, &longs;cilicèt cucurbitulæ exinanitæ.

Neque nouum e&longs;t, intra vi&longs;cera, & partes animalis fieri tumores ex affluxu humorum, cùm tamen non per­cipiamus an prædicti humores &longs;ponte, vel vi ibidem deferantur.

Cap. 6. non dari attracti­onem.

Tran&longs;eo iam ad aliud argumentum adductum pro confirmatione attractionis: Sit DEF vas oblongu&mtail; mercurio plenum, &longs;umaturque fi&longs;tula vi­

trea vtrinque aperta AB, & immerga­tur intra vas DF, quou&longs;que &longs;upremum eius orificium A demergatur infra li­bellam mercurij E; tunc applicetur digi­ti pulpa &longs;upremo orificio fi&longs;tulæ A, vt arctè claudatur. Iam &longs;i &longs;ummitas fi&longs;tu­læ A vnà cum claudente digito eleue­tur, percipitur manife&longs;ta attractio di­giti pulpæ, quam &longs;uprema mercurij &longs;u­perficies tangit, hæc (inquiunt) vio­lentia procùl dubio efficitur à pondere &longs;ubiecti mercurij, cum reuerà digitus, & manus &longs;uftentare debeat pondus prædicti mercurij, non &longs;ecùs, ac &longs;i vncino aliquo digito annecteretur, hinc deducitur quòd detur in rerum natura facultas, & operatio attractiua, & &longs;i hoc verùm e&longs;t (inquiunt) quare in cucurbitulis &longs;imilitèr ab&longs;que funibus, aut vncinis non pote&longs;t &longs;imilis attractio fieri?

Aliud argu­mm con­tra &longs;uperius adductam do ctrinm.

PROP. CXXXII.

In fi&longs;tula vtrinque aperta mercurio plena digito &longs;upernè ob­turata, & infernè intra mercurium demer&longs;a, licèt videa­mur percipere in digito &longs;en&longs;um &longs;uctionis, & ponderis mercurij &longs;ustentati, tamen verè grauamur à cy­lindro aereo &longs;upra vnguem incumbente, & &longs;u­ctio pulpæ digiti à defectu pres&longs;ionis aeris dependet.

Cap. 6. non dari attracti­onem.

REuera Mercurius pulpæ digiti connectitur in A, non vi aliqua attractiua, &longs;ed à compre&longs;&longs;ion&etail; aeris ambientis &longs;upra &longs;tagnans hydrargyrum E va&longs;is &longs;ubiecti; hoc autem confirmatur ex eo, quòd &longs;i altiùs eleuetur fi&longs;tula, vt nimirùm &longs;oli­

tam altitudinem vnius cubiti, & qua­drantis excedat, tunc quidem &longs;uprema mercurij &longs;uperficies leni&longs;&longs;imo motu ab&longs;que vlla difficultate diuellitur, &longs;epa­raturque à digiti pulpa &longs;uprema A, non igitur à vi attractiua mercurius digito annectebatur. Sed quæres; vnde ergò oritur &longs;en&longs;us ille &longs;uctionis, & tractio­nis, qui in prædicta pulpa digiti perci­pitur, & quomodò &longs;u&longs;tentat, atqu&etail; percipit grauitatem mercurij &longs;ubiecti? Re&longs;pondeo, quòd à pondere aeris ma­nui, & digito incumbentis comprimuntur omnes par­tes digiti, excepta illa particula, quæ orificium vitri A attingit, & ab hac compre&longs;&longs;ione exprimitur &longs;an­guis in tumore illo rubicundo pulpæ digiti, quæ in orificio vitri A in&longs;inuatur, quando &longs;patium inane ibi­dem creatur. Præterea ade&longs;t pondus hydrargyri in­tra fi&longs;tulam contenti, quod &longs;u&longs;tinetur à pre&longs;&longs;ione cy­lindri aerei dum comprimit mercurij &longs;uperficiem &longs;ta­gnantis. Vnde ex vna parte habemus pondus cylin­dri aerei, orificium, & digitum in A comprimentis, pariterque ade&longs;t pondus vitri AB, & mercurij in ip­&longs;o contenti, ex altera verò parte ade&longs;t grauitas alte-

rius aerei cylindri prementis &longs;tagnantem &longs;uperfici­em E, & ab hoc &longs;u&longs;penditur mercurius AB. igitur à virtute manus &longs;u&longs;tinetur re&longs;iduum ponderis vltra æ­quilibrium, &longs;cilicèt pondus vitri AB vnà cum ponde­re cylindri aerei orificio, & digito A incumbentis, licèt falsò per&longs;uadeatur &longs;e &longs;u&longs;tinere mercurium &longs;ub­iectum, eique adnexum.

Cap. 6. non dari attracti­onem.

Et profectò ab hac experientia euincitur, quòd tra­ctio illa, quæ in digito percipitur, non &longs;it vera attra­ctio facta ob vacui timorem, quia dum fi&longs;tula minùs cubito cum quadrante eleuatur, mercurius à digito non diuellitur, & proindè &longs;patium inane ibidem non intercipitur, vnde nulla attractio fieri deberet, cùm è contrà maxima fieret quando ob mercurij de&longs;cen­&longs;um efficitur &longs;olita inanitas, & tamen hoc fal&longs;um e&longs;t, cùm in vtroque ca&longs;u ferè æquali vi digiti pulpa de­or&longs;um attrahi &longs;entiatur.

Tandem examinati debet pulcherrima, & ingenio­&longs;i&longs;&longs;ima difficultas, quam cari&longs;&longs;imus amicus Diony­&longs;ius Guerrinus M.D. Ætrur. Ca&longs;tren&longs;is Generalis pre­fectus mihi di&longs;cutiendam propo&longs;uit. Dicebat enim &longs;i in tubis pneumaticis, &longs;eu cte&longs;ibijs, quibus aqua&mtail; haurire &longs;olemus è puteis, aqua eleuatur, non quidem vera attractione, quatenùs embolo eleuato hauritur, vel exugitur aqua &longs;ubiecta, vt pueri calamo intr&atail; aquam immi&longs;&longs;o re&longs;tricto ore, & anhelitu, & &longs;piritu attracto aquam &longs;ursùm eleuant; &longs;ed hoc contingit, quia dum embolus manu &longs;ursùm trahitur, impellitur &longs;ursùm quoque cylindrus aereus embolo incumbens, & proindè prohibetur impeditur que actio compre&longs;­&longs;iua prædicti aerei cylindri &longs;upra aquam &longs;ubiectam. Vis ergo & conatus manus embolum eleuantis sem­per eidem re&longs;i&longs;tentiæ opponitur, nempè&longs;u&longs;pendit e­leuatque eumdem cylindrum aereum &longs;upra embolum incumbentem, igitur &longs;emper eadem vis, idemque co­natus manus requiritur ad &longs;u&longs;tinendum prædictum ae­reum cylindrum, & ad prohibendam eius compre&longs;&longs;i­onem &longs;upra aquam &longs;ubiectam. Hinc inferebat, igitur &longs;iue in tubo cte&longs;ibico &longs;upra libellam &longs;ubiecti putei a­qua magis, vel minùs eleuetur &longs;emper eadem vi, & energia manus &longs;u&longs;pendere embolum, & con&longs;equen­ter aquam eleuare poterimus, &longs;ed hoc e&longs;t fal&longs;um, & contra experientiam, cùm &longs;emper maior vis, & cona­tus requiratur, quo aqua ad maiorem altitudinem in tubo pneumatico eleuatur, igitur fal&longs;um e&longs;t aqua&mtail; eleuari, propterea quòd &longs;u&longs;penditur prohibeturque compre&longs;&longs;io cylindri aerei &longs;upra embolum prædicti in­&longs;trumenti. Cùm è contrà &longs;i reuera vi attractiua à ma­nu embolum trahente &longs;ubleuatur aqua, manife&longs;tu&mtail; e&longs;t, quòd quò altiùs a&longs;cendit maior aquæ copia, pro­indè grauior moles &longs;upra putei libellam &longs;u&longs;penditur eleuaturque, mirum non e&longs;t maius pondus aquæ à maiori vi &longs;u&longs;tentari eleuarique debere, quam minor aquæ copia.

Proponitur pulchett mum argumentum pro attracti­one.

Cap. 6. non dari attracti­onem.

Cap. 6. non dari attracti­onem.

PROP. CXXXIII.

Neces&longs;itate mechanica in tubo pneumatico requiritur maior vis ad trahendum embolum cum adhærente aqua ad altitudinem maiorem, quàm ad minorem &longs;e­cundùm proportionem quam habent aquæ &longs;ubleuatæ pondera, vel mo­menta.

VT verò huic difficultati per&longs;picuè &longs;atisfacia­mus, &longs;upponamus in puteo, cuius &longs;uperficies aquea BC, demergi tubum pneumaticum RB, qui facilitatis gratia continuari intelligatur cum &longs;ip ho­ne inuer&longs;o BIKD; intelligatur que libra radiorum æ­qualium GH, cuius centrum N, & vtrinque pendeant ab extremitatibus æqualia pondera

E, & F, & hæc contingant &longs;uperficiem aquæ BC, itaut ambograuia F, & E comprimant, impellantque aquam ip&longs;am deorsùm, E quidem immedia­tè, F verò mediante embolo QB, ha­beantque figuram cylindricam, & ad modum emboli intra canales &longs;i­phonis &longs;trictè, & arctè moueri &longs;ursum, ac deorsùm po&longs;&longs;int, & &longs;upponamus embolum QB grauitate carere; ad­ueniat po&longs;tea externa vis, quæ &longs;u&longs;tentet pondus F ip­&longs;umque &longs;ursùm impellat, h&ecedil;c profectò non debet e&longs;&longs;e æqualis integro ponderi va&longs;to ip&longs;ius F, proptere&atail; quòd hoc æquilibratur ab æquipondio ip&longs;ius E, & proinde F nullam compre&longs;&longs;ionem exercet, perinde, ac &longs;i grauitate omninò careret, quare à quacumque exili&longs;&longs;ima vi &longs;u&longs;pendi, & &longs;ursùm impelli poterit, &longs;it­
que talis vis &longs;u&longs;pen&longs;iua, vna pars quarta ponderis ip&longs;ius F, igitur pon­dus quod F exercet, erit tres quar­tæ partes totius ponderis E, igitur non ampliùs fiet æquilibrium, &longs;ed pondus E exercebit quadrantem totius &longs;ui ponderis, & cum hoc con­primet &longs;ubiectam a quam C, & proin­dè eleuare poterit in oppo&longs;ito tu­bo &longs;iphonis aquæ molem BM, cu­ius pondus vna quarta pars &longs;it ponderis E, vel F. Po&longs;teà denuò &longs;uperaddita cau­fa externa &longs;ursùm F impellente, & &longs;u&longs;tentante, vt nimirùm remaneat vis comprimens ip&longs;ius E immi­nuta, & æqualis medietati ponderis E. Manife&longs;tu&mtail; e&longs;t magis æquilibrium &longs;uperare graue E, &longs;cilicèt eius momentum erit æquale dimidio totius eius ponderis E, vel F, proindeque eleuabit duplam aquæ molem in aduer&longs;o tubo v&longs;que ad O, vt nimirùm moles aquæ BO dupla &longs;it ip&longs;ius BM, & &longs;ic vlteriùs adueniente no­ua vi &longs;u&longs;tentante pondus F &longs;emper magis diminuetur ip&longs;ius F compre&longs;&longs;io, & tantumdèm præcisè cre&longs;cet momentum ponderis E, & tantundem augebitur ele­uatio aquæ in tubo BR, quaproptèr con&longs;tat quod à maiori vi &longs;ursùm impellente pondus F nece&longs;&longs;ariò ma-ior moles aquæ in tubo pneumatico eleuatur, & è con­uer&longs;o maior moles aquæ in tubo pneumatico BR ele­uata maiorem vim &longs;u&longs;tentantem, & eleuantem exi­git. Intelligatur modò corpus FV e&longs;&longs;e aereum cylin­drum embolo AB incumbens, eumque deprimens &longs;u­pra aquæ libellam B (neglecta facilitatis gratia gra­uitate ip&longs;ius emboli) pariterque &longs;it cor­
pus EX alter cylindrus aereus &longs;uperfi­ciei aquæ C incumbens, igitur quotie&longs;­cumque duo pondera aerea FV, & EX æqualia &longs;unt, æquali vi &longs;ubiectam aquam premunt, & in tali &longs;tatu aqua B nequ&etail; eleuabitur, neque deprimetur, dum equè comprimitur à colunnis aereis FV, & EX æquilibratis; at quando aduenit quæli­bet exigua vis poterit &longs;u&longs;tentare aereum cylindrum FV æquilibratum, & ideò non grauem, eumque &longs;ursùm impellere, & proindè prohibere eius pre&longs;&longs;ionem &longs;upra aquam B, & tunc tanta præcisè erit compre&longs;&longs;io facta à cylindro aereo EX &longs;upra &longs;ubiectam aquam, quanta e&longs;t vis, à qua cylindrus aereus FV &longs;u&longs;tinetur &longs;ubleuaturque, & tanta præcisè erit aquæ moles BS eleuata in tubo pneumatico, igitur quantum præcisè augetur graui­tasip&longs;ius aquæ BS &longs;ubleuatæ, tantum præcisè augeri debet vis illa, qua cylindrus aereus FV &longs;ursùm im­pellitur, &longs;eù tantumdem augeri debet vis manus &longs;ur­sùm embolum trahentis, à quo paritèr aereus cylin­drus FV &longs;u&longs;tinetur impelliturque &longs;ursùm. Et hinc pa-t, quòd nece&longs;&longs;itate mechanica in tubo pneumatico requiritur maior vis ad trahendum embolum quando aqua &longs;ubleuanda e&longs;t ad maiorem altitudinem, quam ad minorem. modò quia &longs;uperficies aquæ B premitur ab aqua BS (non con&longs;iderato embolo) & ab aere FV, & &longs;uper&longs;i­cies aquæ C grauatur tantummodò à cylindro aereo EX æquè graui ac FV (eò quòd in&longs;ignis atmo&longs;phær&ecedil; &longs;ublimitas e&longs;t in cau&longs;a vt exce&longs;&longs;us altitudinis cylin­dri EX &longs;upra cylindri FV altitudinem &longs;it omninò in­&longs;en&longs;ibilis, proindeque cen&longs;eri po&longs;&longs;int aerei cylindri EX, & FV æquè graues) ergo exce&longs;&longs;us grauitatis a­quæ BS compen&longs;ari debet à vi contraria manus A embolum AI trahentis. Sed animaducrtendum e&longs;t quòd vis manus embolum trahentis reuera non ele­uat aquam BS, quia hæc æquilibratur à &longs;ibi æquali momento aeris EX, fed tantummodò manus &longs;u&longs;ten­tat prohibetque pre&longs;&longs;ionem incumbentis aeris FV, æquilibrati cum EX, cuius pre&longs;&longs;ionis momentum æqua­tur ponderi aquæ &longs;ubienatæ BS. hinc fit vt præiudi­cio decepti putemus nos &longs;u&longs;tinere aquam &longs;ubiectam quando reuerà &longs;u&longs;tentamus aerem incumbente&mtail; FV æquilibratum ip&longs;i EX.

Cap. 6. non dari attracti­onem.

Cap. 6. non dari attracti­onem.

Cap. 6. non dari

Nocandum quod vis. embolú non at tra, nec &longs;u&longs;tent at aquam &longs;ctam &longs;ibi­que adhæren­m, &longs;ed po­tiùs &longs;et aereum cylin­ incun­benem.

Tandem cùm altitudo aquæ BS ad 18. cubitos fe­rè peruenerit, licèt deinceps embolus maiori vi alti­ùs trahatur nè minimum quidem aqua vlterius &longs;uble­uabitur, ex quo euincitur aquam non attrahi ab em­bolo, &longs;ed impelli à pondere cylindri aerei collatera­lis, qui cum prædicta aquæ altitudine æquilibratur. Et hæc modo &longs;ufficiant pro euer&longs;ione virtutis attrac­tiuæ.

Cap. 7. d&etail; natura flui­ditatis.

De Natura, & Cau&longs;a fluiditatis.

CAP. VII.

PO&longs;tquam euicimus aquam, & aerem, in eorum­metregionibus ponderare, & grauitatem exer­cere, in&longs;uperque attractionem in natura non dari; po­terit iam natura, & vera cau&longs;a fluiditatis eorum a&longs;&longs;ignari.

Et primò more no &longs;tro de finitionem fluiditatis affe­remus de&longs;umptam ab aliqua in&longs;igni, & euidenti pa&longs;­&longs;ione eius corporis, quod fluidum appellatur. Et pro­fectò quotie&longs;cumque video, atque con&longs;idero diffe­rentiam inter glaciem, & aquam fluentem, ob&longs;eruo in illa duritiem, & con&longs;i&longs;tentiam, qua ifta caret, video enim immi&longs;&longs;o digito, quòd glacies non cedit, aqu&atail; verò fluida facillimè locum præ&longs;tat &longs;ubmer&longs;ioni, & ingre&longs;&longs;ui digiti, perfecteque circa ip&longs;um di&longs;poni­tur, & adaptatur, vt vndequaque eum contingat. Video in&longs;uper non po&longs;&longs;e angulum glaciei impelli, aut quo­modolibet loco-moueri, quin tota ma&longs;&longs;a glacialis &longs;i­mùl moueatur, cum è contrà in aqua fluida po&longs;&longs;it qu&ecedil;­libet eius particula impelli, circumuolui, alij&longs;qu&etail; modis agitari, quie&longs;centibus tamen reliquis partibus eius, vel &longs;altem agitatis motu tardiori, vel non ad ea&longs;­dem partes facto. Po&longs;tremò ob&longs;eruo aquam fluidam perfecti&longs;&longs;imè explanari, & ad libellam horizonti æ­quidi&longs;tantem reduci, quod minimè fieri po&longs;&longs;et, ni&longs;i partes eius extremæ, &longs;uper ficiale &longs;que æquè à medio puncto telluris recederent.

Cap. 7. d&etail; natura flui­ditatis.

Ex hi&longs;ce omnibus phenomenis colligi pote&longs;t pa&longs;&longs;io præcipua ex qua reliquæ omnes dependent atqu&etail; exprimuntur, eritque talis: corpus fluidum erit il­

lud, cuius partium æquè ponderantium pote&longs;t vna à vi externa moueri non motis reliquis, vel diuer&longs;o mo­do agitatis quàm duris corporibus competit. Quæ de­finitio parùm differt ab ea quæ traditur ab Ari&longs;tote­le, vbi ait humidum e&longs;&longs;e, quod facilè termino alieno terminatur, & hoc accidit ex eo, quod po&longs;&longs;unt facil­limè aliquæ partes moueri, non motis teliquis, vel diuer&longs;o motu. Et hoc quidem, vt euidenti&longs;&longs;imum, non indiget vlteriori declaratione.

Definitio fluiditatis.

De gener, & corrup lib. 2. cap. 3.

Re&longs;tat modò præcipua difficultas, an fluidum re­ucra &longs;it corpus continuum, an verò &longs;it di&longs;cretum, &longs;ci­licèt aggregatum ex innumeris particulis &longs;ubdiui&longs;is, qualis e&longs;t aceruus granorum, vel arenæ, & hoc erit oper&ecedil; pretium accuratè examinare, idque præ&longs;tabi­mus o&longs;tendendo quòd.

PROP. CXXXIV.

Corpus &longs;ub&longs;t antiale componi non pote&longs;t ex punctis indiui&longs;ibilibus, licèt numero infinitis.

QVia puncta indiui&longs;ibilia non videntur exi&longs;tere, neque in &longs;ub&longs;tantiali corpore a&longs;&longs;ignari po&longs;&longs;e, ni&longs;i fictione, & mentis cogitatione, nec &longs;unt partes, neque elementa &longs;ub&longs;tantiam corpoream componen­tia, quod patet ex eo, quod punctum additum puncto bis, decies, millies &c. non facit maius, & nil puncta plura differre videntur ab vnico puncto, quandoqui­dem, tàm &longs;ingulare punctum, quàm eorum multitudo nullum &longs;patium quantum occupant, contra ac contin­git in vnitatibus, quæ &longs;imul coniunctæ creant magni­tudinem numericam, ex quo proinde fit, vt vnitates meritò partes, & elementa numeri cen&longs;eantur, no&ntail; verò puncta ip&longs;ius &longs;ub&longs;tantiæ quantæ. Hinc infertur, quod &longs;icut ex infinitis cyfris numerus creari non po­re&longs;t, & ex infinitis non entibus nequit ens confici, &longs;ic exinfinitis non quantis, quæ nec partes nec elementa quantitatis &longs;unt, non pote&longs;t quantum componi; &longs;unt­que puncta indiui&longs;ibilia non quanta, nec &longs;unt partes aut elementa componentia quantitatem; igitur ex in­finitis punctis indiui&longs;ibilibus &longs;ub&longs;tantia corpore&atail; quæ quanta e&longs;t componi, crearique non poterit.

Cap. 7. d&etail; natur flui­ditatis.

PROP. CXXXV.

Secundo loco o&longs;tenden dum est, quòd partes quantæ actu infinitæ, & eiu&longs;dem men&longs;uræ com­ponunt exten&longs;ionem infinitam;

SInt partes quantæ A, B, C, D, E, F, G, &c. actu in­finitæ numero, & æquales inter &longs;e, dico eas ex­

ten&longs;ionem infinitam compone­re. &longs;umatur quælibet quantitas finita cuiu&longs;libet va&longs;titatis RS eiufdem generis cum particulis A, B, C, &c. profectò aut RS. multiplex e&longs;t ip&longs;ius A, &longs;cilicèt hæc illam metitur, vel non; & primò ponamus RS alA men&longs;urari, habebit ergo RS ad A eamdem proportionem, quam aliquis numerus finitus ad vnitatem& ideò in infinita multitudine partium A, B, C, &c&longs;umi pote&longs;t multitudo partium, quæ maior &longs;it numerpartium ip&longs;ius RS, & prædicta maior multitudo partium efficiat exten&longs;ionem X proculdubio X maior eriip&longs;a RS, at aggregatum ex infinitis particulis A, B, C&c. maiorem exten&longs;ionem creat quam prædicta multitudo finita X, ergo multò magis aggregatum ex infinitis particulis maiorem extenfionem efficit, quànhabeat RS, illa verò exten&longs;io quæ maior e&longs;t quacunqquantitate finita, nece&longs;&longs;ariò infinita erit, ergo aggregatum ex particulis quantis numerò infinitis inter &longs;æqualibus efficit exten&longs;ionem infinitam.

Cap. 7. d&etail; natura flui­ditatis.

Secundò &longs;int A, & RS inte

&longs;e incommen&longs;urabilia, patet ipRS addi po&longs;&longs;e portionem aliquam SV ita vt RV multiple&longs;it ip&longs;ius A, & tunc aggregatex infinitis particulis æqualibuA, B, C, &c. maiorem exten&longs;ionem efficiet quàRV, vt mox o&longs;ten&longs;um fuit, & ideò multò maioreexten&longs;ionem, quàm RS, creabit, proptereaque infnitam e&longs;&longs;e concludemus.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CXXXVI.

Partes quautæ actu infinitæ numero, & inter &longs;e inæquales componunt exten&longs;ionem infinitam.

SInt partes AB, CD, EF, GH, IK, &c. numero in­finitæ, & inter &longs;e inæquales. Dico exten&longs;ionem infinitam conflare. Quia dantur omnes partes quan­tæ numero infinitæ, ergò datur earum minima, quæ &longs;it AB, & ex reliquis maioribus &longs;ecentur portiones CL, EM, GN, &c. &longs;ingulæ æquales minimæ AB; & quia particulæ infinitæ inæquales

AB, CD, EF, &c. maiorem exten­&longs;ionem componunt, quàm partes in­finitæ diminutæ, inter &longs;e æquales AB, CL, EM, &c. &, ex præcedenti, infinitæ particulæ quantæ eiu&longs;dem generis AB, CL, EM, &c. inter &longs;e æquales componunt exten&longs;ione&mtail; infinitam, ergò multò magis in&longs;i initæ partes illis ma­iores inæquales AB, CD, EF, &c. exten&longs;ionem infi­nitam efficient, quod erat.

PROP. CXXXVII.

Si eiu&longs;dem aggregati aliquæ partes moueantur cæteris quie­&longs;centibus, vel omnes inæqualibus motibus agitentur, qui tamen non competant, nec aptari pos&longs;int partibus corporis duri, & con&longs;istentis, ne­ce&longs;&longs;ariò illius aggregati partes erunt actu diui&longs;æ.

Cap. 7. d&etail; natura flui­ditatis.

QVærimodo debet &longs;ignum ex quo lumine natu­ræ euidenti&longs;&longs;imè digno&longs;cere valeamus an ali­quod corpus actu diui&longs;um &longs;it implùres partes, vel &longs;it vnum continuum, licèt prædictæ partes ob exiguita­tem, veltran&longs;parentiam earum &longs;int incon&longs;picuæ, & inob&longs;eruabiles; hoc autem &longs;ignunerit motus, & quies, &longs;cilicèt &longs;i con&longs;tat quòd vna pars A compo&longs;iti mouetur varijs modis dum relique adiacentes partes B, H, E, CI, &c. in eodem &longs;itu quie&longs;cunt, certum erit partem illam agitatam A à reliquis di&longs;ci&longs;&longs;am, & di&longs;cretam e&longs;&longs;&etail;. at quando omnes partes eiu&longs;dem compo&longs;iti mouen­tur, videndum qua ratione euidentèr digno&longs;cere po&longs;­&longs;imus an prædictæ partes &longs;int continuatæ, & vnitæ, vel ab inuicem diui&longs;æ, & profectò non &longs;emper inæ­qualitas motuum indicat diui&longs;ionem potiùs quà&mtail; continuitatem, namin vertigine rotæ &longs;olidæ, & du­ræ earum particulæ licèt tenaciter ei affixæ, & con­nexæ &longs;int, uih lominùs mouentur inæqualibus veloci­tatibus &longs;ecundùm proportionem, quam habent di­&longs;tantiæ ab axi firmo eiu&longs;dem rotæ circumductæ, igi­tur in aliquo fluido reuoluto &longs;i orbes ab eius particu­lis eodem tempore de&longs;eripti maiores fuerint, quo magis ab axe reuolutionis recedunt, & &longs;ecundù&mtail; proportionem di&longs;tantiarum, dubitare profectò po&longs;­&longs;umus an particulæ prædicti fluidi &longs;int continuatæ, an verò actu di&longs;cretæ.

Hinc deducitur, quòd &longs;i in rotæ vertigine vna eius pars magis, vel minùs, quàm priùs à centro recedat, vel celeriori, aut tardiorimotu feratr, quàm com-

petit di&longs;tantiæ eius ab axe, tunc nece&longs;&longs;ariò talis par­ticula erit à rota disiuncta, & &longs;egregata. Vt in rot&atail;

AEH reuoluta circa cen­trum D &longs;i eius particulæ A, B, C eodem tempore de­&longs;cribunt orbes AEH, BFI, CGL, eandem proportio­nem habentes quam di­&longs;tantiæ à centro AD, BD, & CD tunc di&longs;tingui non pote&longs;t an pr&ecedil;dictæ parti­culæ &longs;int di&longs;ci&longs;&longs;æ vt arena, vel &longs;int agglutinatæ rotæ &longs;olidæ, propterea quòd id ip&longs;um &longs;ymptoma particulis duri&longs;&longs;imæ rotæ competit. Si verò circunducta rota particula A relicto orbe AHE excurrit per tangentem rectam AM, aut curuam &longs;pi­ralem AN euidenti&longs;&longs;imum &longs;ignum erit particulam A non e&longs;&longs;e annexam, & vnitam, &longs;ed diui&longs;am à rota &longs;o­lida, quia continentèr à centro D magis, & magis re­mouetur vt in N, vel M.

Cap. 7. d&etail; natura flui­ditatis.

Præterea &longs;i particulæ eamdem à centro di&longs;tantiam retinuerint, & eodem tempore, quo rota integra&mtail; reuolutionem BFB ab&longs;oluit, alia particula A, vel maius, vel minus &longs;patium, quàm circulum AEA per­&longs;icit, &longs;cilicèt percurrit arcum AEH, vel AEO, tunc euidentèr con&longs;tat particulam A non e&longs;&longs;e agglutina­tam, &longs;ed diui&longs;am à rota &longs;olida.

Similitèr in motu directo aggregati AEH, &longs;i eius particulæ inæqualibus velocitatibus feruntur, &longs;cili-cèt dum A pertran&longs;it rectam lineam AB alia pars E excurritrectam lineam EC minorem quàm AB, & alia pars H excurrit &longs;patium HD minùs,

quàm EC euidenti&longs;&longs;imum &longs;ignum erit tales particulas A, E, H, diui&longs;as in­ter &longs;e e&longs;&longs;e.

Cap. 7. d&etail; natura flui­ditatis.

Hinc generali&longs;&longs;ima regula elici pote&longs;t, quòd quotie&longs;cunque aggre­gatum corporum mouetur motu di­recto, & eius partes inæqualibus ve­locitatibus feruntur, aut itinera non &longs;unt æqui di&longs;tantia. Vel &longs;i motu circulari circa centrum D agitatur, omnes eius particulæ &longs;piras vt AN de­&longs;cribunt, vel &longs;i circulos pertran&longs;eant velocitates eo­rum proportionales non &longs;unt di&longs;tantijs à centro: vel è contra &longs;emper tardiores &longs;nnt quò magis à centro re­cedunt, vt &longs;i particula C verè tardiori motu feratur, quàm D, & adhùc B tardiori, quàm C, & &longs;ic reliquæ omnes, procùl dubio ex qualibet ex prædictis inæ­qualitatibus euincitur particlas prædictum aggre­gatum componentes omninò inter &longs;e di&longs;eretas, & di­ui&longs;as e&longs;&longs;e, propterea quod hi motus non competunt, nec aptari po&longs;&longs;unt partibus corporis continui con&longs;i­&longs;tentis, & duri.

PROP. CXXXVIII.

Fluidi corporis partes diui&longs;æ inter &longs;e e&longs;&longs;e debent.

Cap. 7. d&etail; natura flui­ditatis.

HIs po&longs;itis animaduerto quòd quotie&longs;cumqu&etail; corpus aliquod fluidum e&longs;&longs;e &longs;upponitur, nece&longs;­sè e&longs;t, vt eius partes actu diui&longs;æ inter &longs;e &longs;int; quia flui­dum habere debet naturalem conformationem di­&longs;po&longs;itionem, & omnia requi&longs;ita vt elicere po&longs;&longs;it illum motum, quem fluxionem vocamus, &longs;cilicèt &longs;i vn&atail; eius pars moueri queat cæteris quie&longs;centibus, vel &longs;i omnes mouentur, percurrant motu directo inæqualia &longs;patia, vel &longs;i circularitèr ferantur, maiorem, vel mi­norem proportionem vertigines habeant, quam di­&longs;tantiæ à centro reuolutionis; hæ enim motiones ef­fici nequeunt, ni&longs;i partes fluidi actu inter &longs;e diui&longs;æ fint, vt mox o&longs;ten&longs;um fuit, igitur quotie&longs;cumque cor­pus aliquod fluidum e&longs;&longs;e &longs;upponitur, nece&longs;&longs;ariò par­tes eius actu inter &longs;e diui&longs;æ erunt.

PROP. CXXXIX.

Fluidum non pote&longs;t habere partes connexas vnvm con­tinuum con&longs;tituentes.

PRæterea &longs;i partes fluidi non e&longs;&longs;ent diui&longs;æ actu, &longs;cilicèt &longs;i aqua haberet omnes eius partes planè connexas, & conglutinatas vnum continuum con&longs;ti­tuentes, atque hæ motu directo, vel circulari moue­rentur intra fluidum &longs;ui generis, &longs;cilicèt intrà aquam &longs;tagnantem, cum eius particulæ minimæ eamdem in­uariabilem di&longs;po&longs;itionem, &longs;ituationem, ac texturam retinere debeant, ac &longs;i partes alicuius duri corporis, velrotæ &longs;olidæ e&longs;&longs;ent, procùl dubio eodem tempore

de&longs;criberent rectas lineas æquales, vel orbes inæqua­les, & cre&longs;centes in eadem proportione, quam di&longs;tan­tiæ à centro, &longs;eu axe firmo habent, nec aliter contin­gere aliquando po&longs;&longs;et. At quia con&longs;tat non vniuersam aquam lacus directè æquali motu moueri, vel conuer­ti vnà cum interna illa portione translata, vel circum­ducta, &longs;ed videmus, quòd remoti&longs;&longs;imæ partes placi­dè omninò quie&longs;cunt, dum intermediæ excurrunt, vel rotantur veloci&longs;&longs;imo motu, nec à maxima veloci­tate internarum partium prædicti corporis, vel fluid&ecedil; rotæ immediatè tran&longs;itur ad partes fluidi remotiores prorsùs quie&longs;centes, quæ officium va&longs;is &longs;uppleant, &longs;ed vt videre e&longs;t in aqua turbida, & in aere fumo&longs;o tran&longs;itur ordinato decremento ab aquæ partibus ve­loci&longs;&longs;imè directo motu agitatis, vel reuolutis per mi­nùs veloces gradatim, quou&longs;que ad extimas quie­&longs;centes perueniatur; non igitur aqua habere poterit partes connexas vnum continuum con&longs;tituentes. His præmi&longs;&longs;is deuenio ad propo&longs;itionem princip alem.

Cap. 7. d&etail; natura flui­ditatis.

Ex p37.

PROP. CXL.

Partes fluidum corpus primum componentes fluidæ non &longs;unt.

SI enim hoc verum non e&longs;t, minimæ particulæ, ex quibus fluidum con&longs;tat, &longs;int &longs;emper fluidæ, &longs;i fie­ri pote&longs;t, ergo diuidendo corpus fluidum inde&longs;inen­tèr, & infinitè numquam deueniemus ad minima&mtail; eius particulam, quæ fluida non &longs;it, &longs;ed &longs;emper flui-darit. Et quia fluidum catenùs motum, quem fluxio­nem vocamus, elicere pote&longs;t, &longs;cilicèt catenus fluidum e&longs;t quatenùs eius aliquæ partes mouentur cæteris quie&longs;centibus, vel diner&longs;is, & inæqualibus motibus agitantur ab ijs, qui competunt duris, & continuis corporibus; ergò ad hoc, vt nulla particula corporis fluidi care at hac pa&longs;&longs;ione fluiditatis; oportet vt &longs;em­per ei conueniat fluiditatis definitio, &longs;cilicèt &longs;emper quælib et eius pars moueri po&longs;&longs;it cæteris quie&longs;centi­bus, vel inæqualibus motibus agitentur, quàm &longs;int il­li, qui duris, & continuis corporibus competunt. Sed partes contiguæ eiu&longs;dem ma&longs;&longs;æ non po&longs;&longs;unt partim moueri, partim quie&longs;cere, vel inæqualibus motibus agitari diuer&longs;o modo, ac continuis corporibus con­petit, ni&longs;i inter &longs;e &longs;int diui&longs;æ, & di&longs;cretæ; igitur nul­la particula fluidi corporis quantumuis exigua a&longs;&longs;i­gnari pote&longs;t, quæ actu di&longs;&longs;ecta, & &longs;ubdiui&longs;a non &longs;it in plures alias particulas; qua propter nunquam perue­niri poterit ad finem enumerationis multitudinis par­tium eius, & ideò talis multitudo maior erit quocun­que numero, &longs;cilicèt maior quacumque quantitat&etail; finita, ergo infinita erit; at infinitæ partes actu diui­&longs;æ &longs;i e&longs;&longs;ent quantæ &longs;iue inter &longs;e æquales, &longs;iue non, e&longs;li­cerent exten&longs;ionem in finitam, ergò &longs;ph&ecedil;ra fluida pal­maris e&longs;&longs;et infinitæ magnitudinis, quod e&longs;t fal&longs;u&mtail;, igitur non quantæ, &longs;ed indiui&longs;ibilia puncta erunt; hoc verò e&longs;t quoque impo&longs;&longs;ibile, cùm infinita puncta ex­ten&longs;ionem quantam nequeant componere: ergò fal­&longs;um e&longs;t, quòd minimæ particulæ ex quibus fluidu&mtail; con&longs;tat, & in quas diuidi pote&longs;t, &longs;int &longs;emper fluidæ, quod erat o&longs;tendendum.

Cap. 7. d&etail; natura flui­ditatis.

Prop. 138.

Prop. 135. & 136.

Prop. 134.

Cap. 7. d&etail; natura flui­ditatis.

Hinc deducitur, quòd corpus fluidum componitur ex minimis particulis non fluidis.

PROP. CXLI.

Idem aliter demon&longs;trare.

SI enim hoc verum non e&longs;t, &longs;cilicèt &longs;i particulæ a­quam fluidam componentes &longs;emper fluidæ &longs;unt, igitur diuidi &longs;emper poterit aqua &longs;ucce&longs;&longs;iuè, & i&ntail; infinitum in particulas, quæ &longs;emper fluidæ &longs;int, hoc tamen primò repugnat ip&longs;imet Ari&longs;toteli, qui negat contra Anaxagoram po&longs;&longs;e quodlibet corpus natura­le retinere eandem naturam &longs;i &longs;emper magis, ac magis per continuam diui&longs;ionem ad exiguas & minimas particulas reducatur; &longs;ic diui&longs;a animalis carne deue­nietur tandem ad particulas, quæ non ampliùs carnes &longs;int; &longs;ic paritèr, vt habent eius expo&longs;itores in elemen­tis facta con&longs;imili diui&longs;ione &longs;ucce&longs;&longs;iua, tandem minu­ti&longs;&longs;imæ particulæ non ampliùs elementarem naturam retinebunt. Hinc igitur licet inferre quòd fluido a­queo in infinitum &longs;ucce&longs;&longs;iuè diui&longs;o deuenietur tan­dem ad particulas eius, quæ fluidæ non &longs;int, &longs;cilicèt cuius vna particula non po&longs;&longs;it moueri quie&longs;centibus reliquis, & propterea omnes &longs;imùl vnico motu agita­ri poterunt, &longs;cilicet con&longs;i&longs;tentiam &longs;olidam haber&etail; neceisè e&longs;t.

Phylib. cap. 4.

Sed relicta Ari&longs;totelis, & Peripateticorum autho-ritate perpendamus rationis vim, & energiam. Si ve­rum e&longs;t aquam fluidam quomodocumque diui&longs;am, & &longs;ubdiui&longs;am &longs;emper fluiditatem retinere, igitur &longs;em­per hi&longs;ce po&longs;tremis particulis fluidis definitio fluidi­tatis &longs;uperiùs tradita competet, &longs;cilicèt aliqua mi­nor particula eiu&longs;dem particulæ moueri poterit quie­&longs;centibus collateralibus partibus. His po&longs;itis, qui&atail; corpora omnia &longs;ublunaria innumeris poris, & forami­nulis peruia &longs;unt, &longs;equitur quòd aqua omnia corpora concreta penetraret, nam concipiamus quemlibet porum &longs;tricti&longs;&longs;imum in va&longs;e ligneo, vitreo, vel metal­lico, certum e&longs;t quòd portio aquea foraminulo præ­dicto &longs;uperpo&longs;ita cui adæquatur, dimen&longs;ionem, & quantitatem habet æqualem amplitudini foraminis, & iuxtà quantitatis naturam &longs;emper diui&longs;ibilem po­terunt concipi particulæ centrales, & &longs;trictiores, quam &longs;it amplitudo eiu&longs;dem pori, quæ particulæ aquæ cen­trales cùm po&longs;&longs;int moueri quie&longs;centibus collaterali­bus, vt &longs;uperiùs expo&longs;ita fluidi natura exigit, ergo ne­ce&longs;&longs;ariò peplitudinem pori liberè excurrere po­terunt, & proindè nullum vas reperietur, per quod aqua penetrare queat: & aduertendum e&longs;t, quòd à qualibet exigua vi motiua impelli, & in&longs;inuari po&longs;&longs;et aqua per prædictas poro&longs;itates, &longs;cilicèt à vi &longs;uæ pro­priæ grauitatis, &longs;eù à quacumque alia vi eam in&longs;ufflan­te, vel impellente, vt po&longs;teriùs o&longs;tendemus; hoc au­tem e&longs;t euidenter fal&longs;um, cùm aqua communis, aut &longs;piritus vini &longs;ubtili&longs;&longs;imus vitri poro&longs;itates penetrare non po&longs;&longs;it, licèt violentèr impellatur, igitur fal&longs;um e&longs;t, fluidum diuidi po&longs;&longs;e in infinitum in partes &longs;emper fluidas; qua propter nece&longs;sè e&longs;t, vt tandem diuiden­do perueniamus ad particulas aqu&ecedil;, qu&ecedil; non ampliùs fluidæ &longs;int, &longs;cilicèt in quibus non vale at moueri vn&atail; eius minima particula quie&longs;centibus collateralibus, proindeque illæ po&longs;tremæ fluidi particulæ erunt con­fi&longs;tentes, quod erat o&longs;tendendum.

Cap. 7. d&etail; natura flui­ditatis.

Cap. 7. d&etail; natura flui­ditatis.

Quòd verò à valdè exigua vi impelli po&longs;&longs;it aqu&atail; per vitri poro&longs;itates, patetex eo, quòd videmus præ­longam trabem &longs;uper aquam &longs;tagnantem po&longs;itam tran&longs;­uersè trahi po&longs;&longs;e à vi exigui capilli, igitur illa exigua vis motiua &longs;uperare pore&longs;t re&longs;i&longs;tentiam tot partiu&mtail; aquæ quot a&longs;&longs;ignari po&longs;&longs;unt in prædicta amplitudine trabis. Vnde conijcitur, quòd vis, quæ requiritur ad impellendam paruam, & acutam fe&longs;tucam natantem debeat e&longs;&longs;e ferè in&longs;en&longs;ibilisb eius maximam minu­tiem, & tamen à tam minima vi mouetur vna aquæ particula non motis collateralibus, & proptereà vis huic æqualis &longs;ufficiens e&longs;t &longs;u perare tenacitatem, qua aquæ particulæ colligantur, vniunturque, erit igitur energia tenacitatis partium aquæ minimi, & exigui roboris, & propterea &longs;uperari poterit à pu&longs;illa vi im­pul&longs;iua.

Nec ob&longs;tat, quòd aqua communis non &longs;it omninò &longs;incera, & ab&longs;que mixtura partium terre &longs;trium, & &longs;o­lidarum, nam licèt hocverum &longs;it, nihilominùs negari non po&longs;&longs;unt partes puræ aquæ, quæ inter minuti&longs;&longs;ima fragmenta terre&longs;tria intercedunt, & ex &longs;ui natura cum &longs;int fluid&ecedil;, po&longs;&longs;ent quidem penetrare inter&longs;titia inter arenulas commixtas cum ip&longs;ametaqua, imò earundem arenularum poro&longs;itates pertran&longs;ire valerent.

Cap, 7. de natura flui­ditatis.

Nec præterea ob&longs;tat, quòd poro&longs;itates vitri, aut metalli non &longs;int directæ, &longs;ed miris modis contortæ, & anfractuo&longs;æ, nec &longs;emper eiu&longs;dem amplitudinis, nam nihilominùs vetari, & impediri non po&longs;&longs;et tran&longs;itus fluentis aquæ, &longs;altem tardiori motu, longiorique ten­pore, quàm &longs;i per poro&longs;itates directas, & æquè latas pertran&longs;ire debui&longs;&longs;et. Hoc autem cùm non contin­gat, &longs;cilicèt aqua intra vas vitre um diù inclu&longs;a num­quam exudet, concedendum e&longs;t, minimas eius parti­culas non fluidas, &longs;ed con&longs;i&longs;tentes e&longs;&longs;e.

Licèt poro&longs;i­tates cuius­libt corpo­ris &longs;int tor­tuo&longs;æ tamen à fluido p­mea po&longs;­&longs;unt.

Quòd verò pori cuiuslibet va&longs;is permeabiles om­ninò &longs;int, nec viæ obturamentis impediantur, occlu­danturque, probari &longs;atis pote&longs;t ex eo quod per eos aliqua fluida penetrant, vt hydrargyrum per poros auri, aqua, oleum, & hydrargyrum quoque per po­ros ligni, & va&longs;is fictilis, quare per eo&longs;dem reliqua omnia fluida nece&longs;&longs;ariò pertran&longs;ire, & fluere debe­rent, &longs;altèm tardiori motu, &longs;i verum e&longs;t, quòd nulla fluidi pars a&longs;&longs;ignari pote&longs;t, quæ paritèr fluida non &longs;it; deberet igitur aer effluere è va&longs;e fictili, & ligneo quotie&longs;cumque violentèr immi&longs;&longs;usibidem conden&longs;atur.

PROP. CXLII.

Ad fluidi con&longs;titutionem requiritur omnium partium diui&longs;io in minimas particulas, talis figuræ, vt vna &longs;uper alte­ram facilè &longs;luere pos&longs;it, & omnes æqualem vim motiuam grauitatis habeant.

Cap. 7. d&etail; natura flui­ditatis.

SI modò philo&longs;ophari velimus non iuxtà homi­num placita, &longs;ed &longs;ecundùm naturæ leges, quatuor conditiones nece&longs;&longs;ariæ e&longs;&longs;e videntur ad fluidi con&longs;ti­tutionem. Primùm vt &longs;it corpus diui&longs;um, & &longs;ub diui­&longs;um in exiguas, & minimas particulas. Secundò vt eius figuræ ad orbicularem formam quam proximè accedant. Tertiò vt harum &longs;uperficies, vel &longs;int per­fecti&longs;&longs;imè l&ecedil;uigatæ ad modum &longs;peculi, vel &longs;altem facilli­mè vna &longs;uper alteram excurrere, & fluere po&longs;&longs;it. Et tandem oportet vt omnes habeant æqualem vim motiuam qua deorsùm tendant, &longs;cilicèt &longs;int æquè graues; Po&longs;&longs;ent hæc omnia (licèt rudi exemplo) non ineptè confir­mari &longs;umptis pluribus globulis cry&longs;tallinis, po&longs;iti&longs;que in aliquo va&longs;e, primò prædicti globuli ad &longs;igara&mtail; va&longs;is adaptantur, & &longs;i manus v&longs;que ad &longs;undum va&longs;is immittatur, tunc globuli prædicti locum cedunt, & ad latera excurrunt, præterea poteritmoueri vna, vel al­tera pila cry&longs;tallina, quie&longs;centibus pilis collaterali­bus, vel parum motis; in&longs;uper po&longs;t agitationem ex­planarentur prædicti globuli, non enim aceruum, aut montem efficerent, veluti grana frumenti, aut arenæ, &longs;ed ob eorum læuitatem facilè excurrerent de&longs;cende­rentque versùs infima loca, & &longs;ic &longs;uprema &longs;uperficies explanaretur, & proximè horizonti æquidi&longs;tantèr di&longs;poneretur. Si po&longs;tea prædictæ &longs;phærulæ cry&longs;talli­næ magis exiguæ, & minutæ e&longs;&longs;ent, tunc multò faci­liùs prædictæ operationes efficerentur, & &longs;i tandèm ad ineffabilem paruitatem redigerentur, non po&longs;&longs;ent neque tactu neque vi&longs;u percipi, &longs;ed apparentem con-

tinuitatem repr&ecedil;&longs;entarent, vt contingit in minuti&longs;&longs;i­mo puluere; & tunc quidem haberi po&longs;&longs;ent effectus omnes fluiditatis, & tamen ma&longs;&longs;a illa e&longs;&longs;et aggregatum ex innumeris globulis cry&longs;tallinis duris, & con&longs;i&longs;tentibus.

Cap. 7. de natura flui­ditatis.

Sed audax quædam &longs;ententia, quæ hi&longs;ce tempori­bus viget, meretur vt aliquanti&longs;per in eius examin&etail; immoremur; concedunt enim fluidum componi ex particulis diui&longs;is, exiguis, l&ecedil;uigati&longs;que, &longs;ed aiunt pal­mariam eius conditionem e&longs;&longs;e, vt particulæ quibus con&longs;tat, diuer&longs;imodè agitentur, &longs;iue motus ille &longs;it ijs connatus, &longs;iue per &longs;ubtiliorem quamdam &longs;ub&longs;tantiam &longs;uo tran&longs;itu ip&longs;as quaqua ver&longs;um voluentem efficiatur.

Carte&longs;ius putat præci­puam fluidi conditionem e&longs;&longs;e vt om­nes elus par­tes inte&longs;tino motu agiten­tur.

Duæ præcipuæ rationes afferuntur ad huius &longs;enten­tiæ confirmationem, prima e&longs;t, quia videmus in me­tallorum fu&longs;ione ab ignis violentia minimas particu­las metallicas verè agitari, idemque ob&longs;eruatur i&ntail; cera, & in reliquis alijs corporibus, quæ ab action&etail; ignis fluida rediguntur, & profectò euidens e&longs;t i&ntail; aqua feruente quod per lebetis poro&longs;itates igneæ exhalationes penetrantes efficiunt innumeras &longs;ph&ecedil;­rulas veloci&longs;&longs;imo motu excurrentes per ip&longs;am aquam, hinc &longs;u&longs;picari licet ab illa vehementi ebullition&etail; fluxilitatem pendere, & licèt aliquando huiu&longs;modi bullæ intra fluidum non con&longs;piciantur, imòcorpus fu­&longs;um &longs;ummè tranquillum, & placidum con&longs;piciatur, vt in plumbo fu&longs;o videre e&longs;t, nihilominùs quia moles plumbi, à fu&longs;ione valdè augetur, & in&longs;uper ab eo fu­mi egredientes non paucas plumbi partes tran&longs;por­tant, manife&longs;tè euincitur fu&longs;um plumbum continuè agitari, ciu&longs;demque partes varijs modis contorqueri ac moueri.

Hoc primò probant ex metallorum fu&longs;ione.

Cap. 7. d&etail; natura flui­ditatis.

Secunda ratio de&longs;umitur ex fermentatione; &longs;i enim grana aliqua &longs;alis in fundo aquæ demergantur, aut quælibet alia materia di&longs;&longs;olubilis, & fermentabilis, videmus, quòd citò vniuer &longs;am aquam &longs;apor, & tinctu­ra illius fermenti in &longs;icit, & alterat, hoc autem minimè fieri po&longs;&longs;et, ni&longs;i particulæ &longs;alinæ tran&longs;portarentur per vniuer&longs;am aquam, quod ab&longs;que agitatione partium eiu&longs;demmet aquæ nullo modo fieri po&longs;&longs;et.

Secundò ex &longs;alium fu&longs;i­one in aqua.

PROP. CXLIII.

Minuti&longs;simæ Corporum particulæ ab inuicem diui&longs;æ læues, & facilè amouibiles, licèt omninò quie&longs;cant, duritiem creare non po&longs;&longs;unt.

ET profectò po&longs;ito, quòd corpus diui&longs;um &longs;it i&ntail; exiguas, & minimas particulas, &longs;i prædictæ par­tes diuer&longs;imodè reuolutæ, & agitatæ fuerint, negari non pote&longs;t eas apparentiam fluidam repr&ecedil;&longs;entare; &longs;ed non proinde oppo&longs;itum verificatur, &longs;cilicèt quòd quotie&longs;cumque dee&longs;t agitatio, & motus minimarum partium alicuius aggregati, idip&longs;um &longs;it corpus durum, & con&longs;i&longs;tens (vt apertè fatentur aliqui recentiores) nam præcipua, & propria pa&longs;&longs;io corporis duri non e&longs;t e&atail; quam Carte&longs;ius affert, &longs;cilicet quòd omnes eius parti­culæ quie&longs;cant in eodem &longs;itu in quo degunt; & ratio e&longs;t, quia talis pa&longs;&longs;io non conuenit &longs;olummodò corpo-ribus duris, cum arenæ particulæ quie&longs;cant, nec tamen cumulum &longs;olidum, & durum efficiant. Ex eo igitur, quod videmus in corpore duro vnam eius parte&mtail; moueri non po&longs;&longs;e que&longs;centibus collateralibus, planè deducitur, quòd non &longs;ufficit &longs;implex contactus par­tium immotarum, &longs;ed præterea nece&longs;&longs;e e&longs;t, vt &longs;int ad inuicem connexæ, & agglutinatæ, vt firmitudinem, & duritiem creare po&longs;&longs;int. & &longs;anè &longs;i reuerà corpus &longs;ub­diui&longs;um fuerit in minuti&longs;&longs;imas particulas rotundas, aut ad rotunditatem proximè accedentes, & careant omni &longs;cabritie, &longs;intque omnes æquè graues, & in qui­ete con&longs;titutæ, tunc e&longs;t impo&longs;&longs;ibile, vt prædictum ag­gregatum durum, & con&longs;i&longs;tens &longs;it, nec poterit &longs;u&longs;ti­neri, vt arena in accliui, & montuo&longs;a eleuatione, prop­terea quod particularum figuræ rotundæ, & l&ecedil;uigatæ non po&longs;&longs;unt vetare excur&longs;um, atque de&longs;cen&longs;um par­tium earundem grauium, & proindè nece&longs;&longs;e e&longs;t vt ex­planentur, nec vna eius pars maiorem eleuatione&mtail; &longs;upra planitiem horizontis habere poterit, quàm a­lia; præterea quodlibet corpus con&longs;i&longs;tens intra præ­dictum aggregatum demer&longs;um &longs;i vim compre&longs;&longs;iuam, &longs;eù grauitatem maiorem habuerit, quàm particulæ illæ &longs;ub diui&longs;æ, facilè poterunt impelli, ac eleuari &longs;u­pra eius libellam, & ob earum rotunditatem, & l&ecedil;ui­tatem nullo negotio excurrere circa corpus demersum po&longs;&longs;unt, idque omni ex parte contingere, atque ad eius figuram accommodari.

Cap. 7. d&etail; natura flui­ditatis.

Argamentum coa &longs;upe­riorem do­cinam.

Sed videamus qua ratione ingenio&longs;i&longs;&longs;imus Author neotericus hanc &longs;ententiam confirmare nitatur, quòd nimium particulæ aquæ glacialis virtute &longs;implicis earum quietis fluiditatem amittant; ait ip&longs;e: multò fa­ciliùs moueri po&longs;&longs;e corpus quodlibet in motu constitutum, quam &longs;i quie&longs;cens, & stabile e&longs;&longs;et, quia in primo ca&longs;u non est nece&longs;­sè, vt producatur, vel creetur motus, cui corpus quodlibet ob natur alem &longs;uam inertiam re&longs;istit, &longs;ed tamummodò vt mo­tus ip&longs;e hactenùs existens, & vigens in eodem corpore diri­gatur.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CXLIV.

Motus, & impetus non faciliùs imprimitur in corpus agi­tatum, quàm quie&longs;cens, &longs;i tamen eius quies fuerit amouibilis.

AT ip&longs;e in hoc ei a&longs;&longs;entiri nullo modo po&longs;&longs;um, nam licèt verum e&longs;&longs;et, quòd faciliùs impelli po&longs;&longs;et corpus in motu con&longs;titutum, quàm quie&longs;cens, non in de &longs;equitur &longs;implicem quietem particularu&mtail; fluidi duritiem eius creare. nam videmus arenæ cu­mulum &longs;olummodò acquirere con&longs;i&longs;tentiam, & duri­tiem, quando glutine, vel arcti&longs;&longs;ima vnione, & angu­lorum mutua in&longs;inuatione connectuntur cius grana, vt in pauimento contingit, non verò quando arenæ particul&ecedil; di&longs;&longs;olutæ placidi&longs;&longs;ima quiete &longs;e mutuò tan­gunt, igitur eodem modo aquæ particulæ læues, di&longs;­&longs;olutæ, tranquilli&longs;&longs;ima quiete &longs;e mutuò tangentes non efficient duram, & rigidam connexionem glacialem. Prætereà &longs;i corpus aliquod in quiete amouibili fuerit con&longs;titutum, &longs;cilicèt &longs;i indifferens fuerit ad motu&mtail; quemlibet, & ad quietem non difficiliùs nouus mo­tus ei imprimitur, quando quie&longs;cit, quàm quando actu mouetur. hoc autem o&longs;ten&longs;um fuit in no&longs;tro Ope­re de Vi Percu&longs;&longs;ionis: Imò &longs;i velimus philo&longs;ophari iuxtà &longs;en&longs;us euidentiam, multoties experimur, quòd maiori difficultate imprimitur nouus motus in eo cor­pore, quod actualitèr mouetur, quam &longs;i in quiete amo­uibili con&longs;titutum fui&longs;&longs;et, & hoc con&longs;tat hac ratione: quia aut motus, qui de nouo imprimi debet, ab im­pellente vergit, ac tendit ad ea&longs;dem partes ad quas corpus mobile fere batur, aut ad partes oppo&longs;itas, vel tran&longs;uersè; & patet, quod in his multò difficiliùs im­primitur nouus motus, quia præter inertiam corpo­ris mobilis, debet quoque &longs;uperari re&longs;i&longs;tentia impe­tus motus contrarij, & &longs;ic videmus, quòd difficiliùs reijcimus, & repercutimus pilam aduenientem, & nobis occurrentem motu contrario, quàm &longs;i eade&mtail; pila omninò motu careret, & pauimento innixa quie­&longs;ceret. Si po&longs;tea motus corporis mobilis, & mouen­tis fiunt versùs ea&longs;dem partes, atque velociori motu mobile, quàm mouens fertur, tunc patet adeò fal&longs;um e&longs;&longs;e faciliùs moueri po&longs;&longs;e corpus illud in motu velo­ciori con&longs;titutum, quàm &longs;i quie&longs;ceret, vt è contrà i&ntail; quiete ab illo impelli po&longs;&longs;et, at in fuga non po&longs;&longs;et à tardiore impul&longs;ore vrgeri; &longs;i verò gradus impetus mouentis corporis maior fuerit illo quo mobile ictum fugit, tunc difficiliùs, &longs;eu tardiùs illud mouebitur, quàm &longs;i in quiete amouibili con&longs;titutum fui&longs;&longs;et; nam in hoc ca&longs;u percu&longs;&longs;io fieret ab integro gradu impetus impellentis corporis, in illo verò ca&longs;u impul&longs;io fie­ret à diminuto gradu velocitatis eius, &longs;cilicèt ab ex­ce&longs;&longs;u &longs;upra velocitatem fugientis corporis. Prætereà in corporibus concretis non omninò duris, nouus mo­tus imprimi non pote&longs;t in in&longs;tanti, &longs;ed in tempore, vt alibi o&longs;ten&longs;um e&longs;t, non contactu &longs;implici, &longs;ed &longs;ociali motu mouentis, & mobilis, hoc autem faciliùs con­&longs;equi pote&longs;t in corpore aliquo quie&longs;cente amouibi­litèr, quàm &longs;i agitetur directè, vel tran&longs;uersè. Hinc colligitur fal&longs;um e&longs;&longs;e, quòd faciliùs impelli po&longs;&longs;et corpus agitatum, quàm quie&longs;cens, &longs;i modò quies fue­rit amouibilis, vt dictum e&longs;t. Et profectò quies ill&atail; particularum cuiuslibet corporis firmi, & duri no&ntail; erit amouibilis, &longs;cilicèt illæ particulæ non &longs;unt indif­ferentes ad motum, cum non à qualibet exigua, & mi­nima vimotiua moueri, & diuelli ab integra ma&longs;&longs;&atail; dura queant, &longs;ed requiritur in&longs;ignis violentia vt par­ticulæ aquæ glaciatæ à tota ma&longs;&longs;a &longs;eparentur; ex quo proinde inferre licet, quòd vt plurimùm figuræ præ­dictarum particularum durum corpus componentium, nec &longs;unt regulares, nec l&ecedil;uigatæ, &longs;ed miris modis an­gulo&longs;æ, ramo&longs;æ, contortæ, & vncinatæ, & proindè partes eius a&longs;peræ, & angulo&longs;æ &longs;e&longs;e contingentes, & vici&longs;&longs;im vna intra &longs;patium alterius in&longs;inuata, po&longs;&longs;unt mutuò &longs;atis benè congruere, componereque qua&longs;i pa­uimentum, & opus te&longs;&longs;ellatum, & &longs;ic non pote&longs;t vna particula ex toto aggregato diuelli extrahique, no&ntail; quidem propter eius quietem, aut defectum motus, &longs;ed tantummodò quia eius concatenata &longs;tructura dif­ficilè dtur.

Cap. 7. d&etail; natura flui­ditatis.

Cap. 7. d&etail; natura flui­ditatis.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CXLV.

Commotio partium metalli, vel vitri, ab gne fu&longs;i per ac­cidens in eis fluiditatem creat, quatenùs &longs;cilicèt ea­rum figuræ angulo&longs;æ ab inuicem &longs;eparantur, & ob ignis interpo&longs;itionem po&longs;&longs;unt vna &longs;uper alteram fluere.

ET reuerà quotie&longs;cum que perpendo, quanta co­pia, & vehementia ignis requiritur, vt aren&atail;, vitrum, ferrum, aut aliud durum metallum, in formam fluidam redigatur, haud per&longs;uaderi po&longs;&longs;um particulas minimas horum corporum po&longs;t diui&longs;ionem ab igne fa­ctam reduci po&longs;&longs;e ad figuras regulares læuigatas, & ad rotunditatem accedentes, &longs;ed puto maximè angulo­&longs;as, a&longs;peras, & elongatas e&longs;&longs;e debere, & ideò difficil­limè po&longs;&longs;e contorqueri reuoluique inter contiguas &longs;ui generis particulas. in hi&longs;ce duos effectus igne&mtail; producere mihi veri&longs;imile videtur, primò, quòd vnan­quamque partem di&longs;&longs;ociat, atque à reliqua &longs;eparat per aliquod &longs;en&longs;ibile interuallum, hocque efficitur à tran&longs;itu multiplicium, & vehementi&longs;&longs;imarum exhala­tionum, & particularum ignearum inter&longs;luentiu&mtail;, virtute cuius particulæ &longs;olidæ arenæ eodem modo ab inuicem di&longs;gregatæ di&longs;ponuntur, ac puluis terreus intra aquam infu&longs;us, & di&longs;per&longs;us, qui eam luto&longs;am, & c&ecedil;no&longs;am reddit. Quòd verò arenæ, vel ferri fu&longs;i par­ticulæ reuerà per aliquod interuallum ab inuicem di­&longs;cretæ, & &longs;eparatæ &longs;int, euincitur ex eo, quòd moles eiu&longs;dem ferri, vel vitri fluentis in&longs;ignitèr augetur &longs;u­pra molem, quam idem corpus durum, & con&longs;i&longs;tens priùs habebat; ignis ergò copio&longs;i&longs;&longs;imè, & vehemen­ti&longs;&longs;imè fluens inter particulas ferri, vel vitri idem pro­pemodum præ&longs;tat, ac rotulæ, vel cylindri &longs;uper quo­rum rotunditatem lapides angulo&longs;i, & figuras irre­gulares habentes labuntur, vel v&longs;um præ&longs;tat &longs;ebi, vel cuiuslibet alterius corporis vnctuo&longs;i, ope cuius a­renulæ a&longs;perrimæ lubricitatem acquirere po&longs;&longs;unt, & v­na particula &longs;uper aliam facili negotio circumuolui, agitari, ac dilabi pote&longs;t, quod perindè e&longs;t, ac &longs;i præ­dictæ particulæ vitri, aut ferri acqui&longs;iui&longs;&longs;ent figuram l&ecedil;uem, rotundam, vel orbicularem &ecedil;mulantem. Ve­rum tamen e&longs;t, quòd huiu&longs;modi operatio effici nullo modo pote&longs;t ab&longs;que commotione, vertigine, & tran&longs;­po&longs;itione minimarum partium metalli, vel vitri, &longs;ed non indè euincitur fluiditatem in tali ca&longs;u ab&longs;olutè dependere à prædicta commotione partium, ni&longs;i ex accidenti, quatenus non po&longs;&longs;unt &longs;egregari, & fluere particulæ a&longs;peræ, & angulo&longs;æ ferri, vel vitri ab&longs;que &longs;uperabundanti, & vehementi profluuio ignis, à quo demùm particulæ ip&longs;æ &longs;olidæ lubricitatem, & motum acquirunt. Hoc autem bellè confirmatur ab experi­mento adducto à docti&longs;&longs;imo Roberto Boile quando alaba&longs;tri puluerem ab igne feruenti fluxibilitatem ac­qui&longs;iui&longs;&longs;e ait, at po&longs;tmodum quælibet particula eiu&longs;­dem fluoris &longs;upra papyrum refrigerata reperie batur aggeries arenularum minuti&longs;&longs;imarum, neque concre­tum, & &longs;olidum corpus effieiebat, vt in vitro, & fer-ro po&longs;t fu&longs;ionem refrigerato videre e&longs;t.

Cap. 7. de natura flui­ditatis.

Hoc expe­rimento con­probatur.

Cap. 7. d&etail; natura flui­ditatis.

Sed ad maiorem huius doctrinæ euidentiam con­&longs;ideretur aggeries arenæ minuti&longs;&longs;imæ, & aridæ, hæ quidem non excurrunt, neque lubricitatem habent, &longs;i po&longs;tea immi&longs;&longs;a, & intercepta aqua luto&longs;am formam acquirat, tunc particulæ aquæ inter arenulas intercep­tæ nedùm eas di&longs;&longs;ociant, &longs;ed velutirotæ, vel cylin­druli, aut materia aliqua vnctuo&longs;a commoditatem eis præ&longs;tat, vt po&longs;&longs;int excurrere vna particula arenæ &longs;u­per aliam contorqueri, atque agitari, & tandem ob natiuam grauitatem quælibet earum deorsùm ten­dendo explanantur, & ad &longs;uperficiem planam hori­zontalem rediguntur, quòd priùs ab&longs;que aqua ill&atail; inter arenulas intercepta in cumulum &longs;atis accliuem &longs;u&longs;tinebatur, acquirit ergò ma&longs;&longs;a illa areno&longs;a vnà cum aqua con&longs;i&longs;tentiam fluidam, explanatur, & reci­pit figuram continentis va&longs;is, non &longs;ecùs, ac vitrum, & &longs;errum fu&longs;um efformatur, & paritèr ad in&longs;tar glo­bulorum cry&longs;tallinorum, qui licèt &longs;int aridi ab &longs;que vllo fluido admixto, & omninò quie&longs;cant in va&longs;e ali­quo, neque agitentur, omnes tameniam dictas flui­di proprietates retinere videntur.

Et exemplo con&longs;irma­tur.

PROP. CXLVI.

Requiritur vis motiua grauitatis in omnibus partibus fluidi, non vt fluiditatem constituat, &longs;ed vt ex plan are he­rizont aliter fluidum pos&longs;it.

VErum tamen e&longs;t, quòd illa præcipua conditio, & proprietas fluidi, qua explanatur, & æqualitèr iacet in plano horiz ontali, nullo pacto verificari po­te&longs;t, ni&longs;i in ip&longs;o fluido ponatur virtus aliqua motiua, qua &longs;i omninò careat, nullo pacto poterit aqua fluida explanari, & ad libellam horizontalem reduci. At huiu&longs;modi virtus motiua longè diuer&longs;a e&longs;t ab ea, quæ exigitur à Carte&longs;io, eiu&longs;que &longs;ectatoribus, non eni&mtail; e&longs;t motiua virtus vaga, & irregularis, quæ inordina­tam agitationem &longs;ursùm, & deorsùm, & tran&longs;uersè continuato fluxu efficiat, &longs;ed e&longs;t tantummodò vis, at­que impetus naturalis grauitatis, ope cuius particu­læ omnes fluidi æquali ni&longs;u tendunt, ac feruntur deor­sùm; &longs;ic enim æquatis momentis efficitur æquilibrium partium eiu&longs;dem fluidi, vnde &longs;ub&longs;equitur æqualis di­&longs;po&longs;itio earum horizontalitèr; &longs;i enim huiu&longs;modi gra­uitas in fluido deficeret, non po&longs;&longs;et virtute æquilibrij æqualitèr di&longs;poni, &longs;ed vna eius pars depre&longs;&longs;a, alia ve­rò &longs;ublimis efficeret inæqualem, & a&longs;peram &longs;uperfi­ciem externam eius, compo&longs;itam ex vallibus, & mon­tibus. Nece&longs;&longs;ariò ergò fatendum e&longs;t in hi&longs;ce fluidis no&longs;tratibus vim motiuam aliquam ade&longs;&longs;e vt omnes æquali vi, & impetu, ad ea&longs;dem partes, &longs;cilicèt deor­sùm tendant. Et profectò &longs;i ponerentur motus vagi irregulares, & contrarij in eodem corpore fluido, vt aduer&longs;arij exi&longs;timant, &longs;equeretur de&longs;tructio eiu&longs;dem hypothe&longs;is, nam cùm in eadem aqua v. g. non po&longs;­&longs;int omnes particulæ eiu&longs;dem aquæ ex condicto &longs;i­mul ad ea&longs;dem partes ordinata &longs;eriè moueri, vt i&ntail; progre&longs;&longs;u alicuius cohortis, vel vt in &longs;upplicationi­bus fieri &longs;olet, omninò nece&longs;sè e&longs;t, vt aliæ partes &longs;ursùm a&longs;cendant, aliquæ verò deorsùm ferantur, & proinde videtur impo&longs;&longs;ibile, atque incredibile, vt aliquando prædictæ partes motibus contrarijs &longs;ibi mutuò non occurrant, & proptereà &longs;e mutuò no&ntail; impediant, & ad quiet em non redigantur. Cùmque ab&longs;que illa vertigine, & agitatione partium fluidi­tatem exi&longs;tere negent; imò duritiem creari affirment. Sequitur ex eadem hypothe&longs;i (in qua commotiones partium aquæ ad fluidi con&longs;titutionem requiruntur) effici duritiem, & con&longs;i&longs;tentiam, &longs;altèm in illis parti­culis fluidi, in quibus quies creatur, quod præcisè de&longs;truit eorum hypothe&longs;im.

Cap. 7. d&etail; natura flui­ditatis.

Cap. 7. de natura flui­ditatis.

In&longs;uper &longs;i vera e&longs;t prædicta vis motiua partiu&mtail; fluidi &longs;ursùm, & deorsùm illa profectò quanta erit, & certi, ac determinati gradus energiæ, quare no&ntail; poterit &longs;uperari à minima, & exigua vi externa eam horizontalitèr impellente, qualis e&longs;t vis tenui&longs;&longs;imi ca­pilli, quo nauim in aqua &longs;tagnante trahemus.

Re&longs;tat modò po&longs;trema difficultas, quomodò nimi­rùm aqua fluida, & quodlibet men&longs;truum ex vegeta­bilibus, &longs;alibus, & mineralibus tincturas extrahunt, ac fermentatione quadam corpora illa di&longs;&longs;olunnt, ac per vniuer&longs;um fluidum &longs;pargunt, diffunduntque; & quia huiu&longs;modi operatio ab&longs;que agitatione aæ, & fluidi fermentantis percipi non pote&longs;t, hinc con­cludunt aquam, & fluidum quodlibet componi ex particulis miris, & varijs modis agitatis, à qua tan­dem partium agitatione fluxibilitatem creari putant.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CXLVII.

Experimenta fermentationum, & di&longs;&longs;olutionis &longs;alium, li­cèt non omnia vera &longs;int, non tamen euincunt fluidi­tatem &longs;emper à continua partium agitatione pendere.

ET hìc primò non negabo exhalationes igneas, & alia corpora &longs;e mouentia excurrere, atqu&etail; penetrare corpora omnia concreta, & ide ò fluidorum partes commouere; &longs;ed non proindè confiteri cogi­mur fluiditatem à continua agitatione partium eius pendere, quandoquidem non omnes experientiæ, quæ ab Aduer&longs;arijs afferuntur veræ &longs;unt, & illæ, quæ ve­ræ &longs;unt non euincunt partes omnes eiu&longs;dem corpo­ris fluidi perpetuò agitari, atque commoueri, itaut ne minima particula in aliquo angulo fluidi remane­at quie&longs;cens, & ab&longs;que vlla agitatione, &longs;altem per aliquod breue tempus. & primum &longs;i granum &longs;alis &longs;o­lidum in fundo aquæ immergatur, verùm non e&longs;t quòd citò vniuer&longs;a aqua va&longs;is &longs;al&longs;edine imbibitur, ni&longs;i va&longs;a &longs;int ampla, & aqua &longs;it agitata, &longs;i verò &longs;umatur fi&longs;tu­la vitrea &longs;atis angu&longs;ta, atque in eius fundo &longs;al appo­natur, aqua verò placidè, & &longs;olertèr &longs;ali &longs;uperpo­natur, euitata, quantum fieri pote&longs;t, agitatione, & commotione eius, tunc aqua, quæ in &longs;ummitate fi&longs;tu­læ reperitur, &longs;al&longs;edine non afficitur, & hoc etiam à Boile experimento comprobatum fuit: vnde conij­citur, quòd reuerà aqua ob eius æquilibrium facilè pote&longs;t commoueri, & &longs;ic repetitis conuolutionibus &longs;ursùm, & deorsùm &longs;ecum tran&longs;portare valet minu­ti&longs;&longs;imas &longs;alis particulas, & hoc citiùs con&longs;equitur &longs;i agitatio vehemens fuerit facta, nimirùm ab impellen­te externo, vel ab ignis vehementia per vitri poro&longs;i­tates penetrante, & per aquam a&longs;cendente; tame&ntail; quando in fi&longs;tula angu&longs;ta, & alta non æquè commo­dè, & facilè aqua agitari, vel &longs;emèl incepta agitatio­ne promoueri non pote&longs;t, tunc &longs;alis particulæ non a­&longs;cendunt v&longs;que ad &longs;upremam aquæ &longs;ummitatem, quia nimirùm, licèt aqua æquilibrata à qualibet vimotiua moueri, & impelli po&longs;&longs;it, nihilominùs quando agita­tio non e&longs;t vehemens, & copio&longs;a, citò extinguitur, cum reliqua moles aquæ &longs;uprema non impul&longs;a ob &longs;ui na­turalem inertiam, & aliqualem vi&longs;co&longs;itatem violen­tiæ motus aliquo pacto re&longs;i&longs;tat, proindeque impre&longs;­&longs;us motus in infimis aquæ particulis citò retardatur, extinguitur que à reliquis aqu&ecedil; partibus in quiete con­&longs;titutis, & hac de cau&longs;a motus debilis in fundo factus propagari v&longs;que ad va&longs;is &longs;ummitatem non pote&longs;t.

Cap. 7. d&etail; natura flui­ditatis.

Fermenta­tiones, & ex­tractiones chymicæ ab&longs; que motu fluidi men­&longs;trui fieri ne queunt; at du bitatu an motus, qui in ftio­ne ob&longs;erua­tur, cau&longs;a vel effectus fermentatio­nis.

In&longs;uper, quòd prædictæ fermentationes, & tinctu­ræ extractionum chymicarum fierinon po&longs;&longs;int ab&longs;que motu, & agitatione fluidi men&longs;trui, conceditur, vt cer­tum, & euidens, &longs;ed dubitatur controuertiturque, an motus, qui in fermentatione ob&longs;eruatur, &longs;it cau­&longs;a, vel effectus eiu&longs;dem fermentationis, &longs;cilicèt a&ntail; motus ille antecedenter &longs;it proprius fluidi corporis, & fluiditatem con&longs;tituat, &longs;itque cau&longs;a effectiua fer­mentationis, an è contrà di&longs;&longs;olutio &longs;alium, & reliquæ fermentationes ab alia cau&longs;a longè diuer&longs;a depen­deant, à qua producatur veluti effectus motus ill&etail;, qui in fermentatione ob&longs;eruatur. Modò &longs;i o&longs;tende­rimus, quòd &longs;implex grauitas fluidi ratione quadam mechanica, & iuxtà leges æquilibrij in&longs;inuare, & im­pellere pote&longs;t fluidi particulas intra poro&longs;itates &longs;a­lium mineralium, & vegetabilium, vndè po&longs;tea con­&longs;equatur agitatio, & ebullitio, quam in fermentatio­ne con&longs;picimus, procùl dubio non licebit ex hoc ex­perimento inferre motum illum antecedenter fluido competere, & fluiditatem con&longs;tituere.

Cap, 7. dnatura flui­ditatis.

PROP. CXLVIII.

Commotio aquæ, quæ in &longs;pongiæ madefactione contingit, non e&longs;t proprin ip&longs;ius aquæ, neque fluiditatem eius co­&longs;tituit, &longs;ed e&longs;t effectus dependens à grauitate eiu&longs;dem fluidi.

IMmergamus priùs in aqua fru&longs;tum &longs;pongiæ, con­&longs;tat &longs;pongiæ &longs;ub &longs;tantiam continere innumeras po­ro&longs;itates exiguas, & inter &longs;e communicantes ad in&longs;tar fi&longs;tularum exiguarum, quæ aut aere replentur, aut omninò inanes &longs;unt. Tunc nemo negabit aquam pro­prio, & naturali pondere in&longs;inuari debere intra &longs;pon­giæ poro&longs;itates, quia verò hoc exequi non pote&longs;t ab&longs;que motu, & agitatione ip&longs;ius aquæ, nece&longs;sè e&longs;t, vt ambientes partes fluidi contiguæ, & proximæ con­&longs;equutiuo quodam motu agitentur, dum ill&ecedil; intra &longs;pon­giæ poro&longs;itates immittuntur, quæ commotiones inæ-quales, & variæ e&longs;&longs;e debent, & ad diuer&longs;as plagas tendentes, prout in &longs;pongiæ poro&longs;itatibus &longs;upremis infimis, & lateralibus aqua ingreditur; at quia &longs;e­mel aqua commota nece&longs;&longs;ariò impetum concipit, er­gò nece&longs;sè e&longs;t, vt vis prædicti impetus impre&longs;&longs;i mini­mè otio&longs;a &longs;it, proindèque percu&longs;&longs;iones inferat tùm particulis &longs;olidis ip&longs;ius &longs;pongiæ, cùm etiam particu­lis aquæ contiguæ, quare non poterit extingui om­ninò prædicta agitatio, ni&longs;i po&longs;t aliquod tempus, po&longs;t­quàm &longs;cilic èt ab impedimentis à glutine partium eiu&longs;­demmet aquæ illatis, impetus præconceptus extin­guatur. Patet ergò, quòd agitatio aquæ, quæ in &longs;pon­giæ madefactione contingit, non e&longs;t propria ip&longs;ius a­quæ, neque fluiditatem eius con&longs;tituit, &longs;ed potiùs e&longs;t effectus dependens à vigrauitatis eiu&longs;dem uidi, quatenùs iuxtà naturæ in&longs;titutum, & hydro&longs;taticæ leges in&longs;inuari debet intra &longs;pongiæ poro&longs;itates, vel inanes, vel à leuiori corpore aereo occupatas.

Cap 7. d&etail; natura flui­ditatis.

PROP. CXLIX.

Commotio aquæ ad in&longs;tar ebullitionis, quæ in pumicis ma­defactione ob&longs;eruatur, non e&longs;t propria, & con&longs;titu­tiua fluidatis eius, &longs;ed e&longs;t effectus dependens à pondere eiu&longs;dem fluidi.

IMmittatur po&longs;tea intra aquam pumex loco &longs;pon­giæ, cuius poro&longs;itates aere refertæ &longs;unt, tunc aqua vtpotè grauior aere intra prædictas poro&longs;itates con­tento &longs;en&longs;im in pumicis exterioribus foraminibus in-&longs;inuari debet, & proindè aereæ particulæ, quæ poru­los occupabant, expelli debent, & hæ cùm in fundo aquæ permanere nequeant, nece&longs;sè e&longs;t vt &longs;ursùm per aquam a&longs;cendant expre&longs;sæ à maiori pondere ip&longs;ius aquæ; dum verò granula, &longs;eu ampullæ aereæ &longs;ursùm feruntur, & ebullitionem quamdam oculis repr&ecedil;&longs;en­tant, fieri non pote&longs;t, vt aqua per quam tran&longs;eunt, ali­quo pacto non agitetur commoueaturque tum expri­mendo aerem, cùm etiam cedendo locum aeri tran­&longs;ituro. Habemus iam nouam cau&longs;am agitationis, & commotionis ip&longs;ius aquæ præter priùs expo&longs;itam, quan­ nimirùm aqua vi &longs;uæ grauitatis in&longs;inuabatur intra &longs;pongiæ poros; nam præterea dum aerei globuli ex­pre&longs;&longs;i, & à pumice exclu&longs;i per aquam a&longs;cendunt, ne­ce&longs;&longs;ariò aqua agitari quoque debet, igitur vniuer&longs;a illa commotio, & veluti ebullitio aquæ habet causam efficientem, quæ e&longs;t &longs;implex aquæ grauitas, quar&etail; non licèt inferre, quòd pr&ecedil;dictus motus ebullitionis, qui in aqua po&longs;t immer&longs;ionem pumicis con&longs;picitur, &longs;it &longs;ignum, & euincat motum illum proprium e&longs;&longs;e ip­&longs;ius aquæ, & fluiditatem eius con&longs;tituere.

Cap, 7. dnatura flui­ditatis.

PROP. CL.

Aquæ commotio à qua gleba di&longs;&longs;oluitur di&longs;pergiturque per eam non e&longs;t propria, & fluiditatis con&longs;titutiu &longs;ed producitur àgrauitate fluidi.

SI po&longs;tea gleba arida intra aquam mergatur, quia inter pumicem, & glebam hoc di&longs;criminis inter-cedit, quòd parietes porulorum pumicis duri sunt con­&longs;i&longs;tentes, & inter &longs;e connexi, & vniti, è contrà in gle­ba parietes pororum &longs;unt valdè fragiles, & di&longs;&longs;olubi­les; vnde &longs;equitur, quòd aquæ particulæ vi grauitatis intra poros glebæ in&longs;inuatæ nedùm expellant aerem ibi contentum, &longs;ed etiam arenulas glebam con&longs;titu­entes, quæ tantummodò &longs;e tangunt, & nullo alio vin­culo, nec glutine nectuntur, facilè ab inuicem di&longs;&longs;o­cient di&longs;pergantque. porrò cùm ad aquæ immi&longs;&longs;ionem, & aeris expre&longs;&longs;ionem, atque a&longs;cen&longs;um nece&longs;&longs;ariò mo­tus, & agitatio ip&longs;ius aquæ con&longs;equatur, hic verò mo­tus ab&longs;que impetu e&longs;&longs;e non po&longs;&longs;it, qui cùm vim cuiu&longs;­cumque ponderis finiti &longs;uperet, vt demon&longs;trauimus, facilè poterit exiguas illas arenulas di&longs;&longs;olutas nedum lateraliter, &longs;ed etiam &longs;ursùm aliquanti&longs;per impelle­re, & hinc oritur turbida quædam nebula, quæ pro­pè glebam demer&longs;am con&longs;picitur diù per&longs;euerans. Ex vniuer&longs;a hac naturali operatione nemo &longs;anæ mentis eliciet aquæ particulas continuo, & vago motu agi­tarinaturali in&longs;tinctu, & ab hoc principio produci glebæ di&longs;&longs;olutionem, di&longs;per&longs;ionemque arenularum eius, & feruoris, qui in aqua tunc temporis con&longs;pici­tur, nam hæc omnia habent &longs;uam cau&longs;am nece&longs;&longs;ariam, nempè aquæ grauitatem, quæ pote&longs;t, & debet nedum expellere &longs;ursùm leues aeris particulas intra glebæ poro&longs;itates contentas, &longs;ed etiam di&longs;&longs;oluere, & di&longs;per­gere &longs;uo impetu puluerulentas glebæ particulas per ip&longs;ammet aquam.

Cap. 7. dnatura flui­ditatis.

In lip.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CLI.

Maior, & velocior aquæ commotio, quæ in &longs;alium di&longs;&longs;olu­tione ob&longs;eruatur, non pendet ab intrin&longs;ece, & natura­li motu aquæ, &longs;ed à fimplici eius gra­uitate.

COgitemus po&longs;tea &longs;alem e&longs;&longs;e glebam ab aqua di&longs;­&longs;olubilem, qui con&longs;tatex &longs;uis minimis parti­culis figuratis non vndequaque &longs;e tangentibus, con­nexi&longs;que, & proindè &longs;alis gleba habet innumeros porulos, & canaliculos inter&longs;per&longs;os, qui vt plurimum non replentur, nec occupantur ab aere, cùm &longs;int val­dè exigui angu&longs;tique, &longs;ed aut à materia valdè tenui, vel potiùs vacui omninò &longs;unt. Con&longs;tat aliundè, quod aqua facillimè &longs;ali vnitur, connectitur, eiu&longs;que po­ro&longs;itates penetrat, contra, ac in pumice, ligno, & alijs corporibus contingit, in quibus madefactio, & a­quæ penetratio non fit, ni&longs;i longo tempore, & diffi­cilè (&longs;iuè hoc pendeat ab aere contento in horu&mtail; poro&longs;itatibus, &longs;iuè ab incongruentia pororum.) Ex hac, inquam, maxima facilitate, qua aqua &longs;alibus in­&longs;inuatur, licet inferre, quòd motu velociori accurrat ad occupanda illa &longs;alium foraminula, & ideò maio­ri, & vehementiori impetu diffoluat &longs;e paretque par­ticulas &longs;alium, ea&longs;que vehementius quoque impellat vnà cumreliqua ambiente aqua, quæ ne dum con&longs;e­quutiuo motu celeriùs agitatur, &longs;ed etiam ab a&longs;cen&longs;u leuiorum particularum, quæ in porulis &longs;alium conti-nebantur, commouetur. Non e&longs;t po&longs;tea difficile à ve­hementiori impetu, & motu ip&longs;is aquæ minimas &longs;a­lis particulas ad loca remotiora di&longs;pergi, atque trans­ferri, quæ &longs;uo &longs;apoe acri ferè vniuer&longs;am aquam va­&longs;is ampli inficiant. Et hic quoque con&longs;tat vniuer&longs;am hanc operationem fermentatiuam non pendere ab in­te&longs;tina motione partium aquæ fluxibilitatis con&longs;titu­tiua, &longs;ed à &longs;implici aquæ grauitate legibus mechani­cis operante, vt dictum e&longs;t.

Cap. 7. d&etail; natura flui­ditatis.

Ex &longs; do­ctrina &longs;equvidetur, quod comple­ta di&longs;&longs;olutio­ne &longs;alis, eius particulæ, vt graues ad fum dum va&longs;is deent; & c aqua dulcis­redtur, quod &longs;t fal­&longs;um.

Sed hìc difficultas oritur, &longs;i verum e&longs;&longs;et; quòd à vi grauitatis aqua intra poros &longs;alium in&longs;inuata impetum acquireret, & &longs;ic &longs;alia di&longs;&longs;olueret, & feruorem crea­ret, ergò po&longs;tquam &longs;emel completa e&longs;&longs;et di&longs;&longs;olutio &longs;alis, & extinctus feruor ebullitioque, redacta e&longs;&longs;et aqua &longs;apida ad exactam tran quillitatem, non po&longs;&longs;ent &longs;alis particulæ grauiores &longs;pecie ip&longs;a aqua &longs;u&longs;pen&longs;æ retineri in ip&longs;amet aqua, &longs;ed &longs;ponte &longs;ua &longs;altem tar­diori motu ad fundum va&longs;is deciderent, proindeque aqua &longs;uprema dulcis omninò remaneret, quod e&longs;t fal&longs;um, igitur dicendum quòd non ab impetu fer­mentationis dependente à vi grauitatis fluidi parti­culæ &longs;alis di&longs;perguntur, &longs;ed potiùs ab inte&longs;tina, & na­turali partium aquæ agitatione, fluiditatemque eius con&longs;tituente perpetuò nouis ictibus, & impul&longs;ionibus &longs;alis partieulæ retinentur natantes intrà aquæ &longs;ub­&longs;tantiam.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CLII.

Completa di&longs;&longs;olutione &longs;alis particulæ eius innatantes non &longs;u­&longs;penduntur ab intestina aquæ commotione, &longs;ed ab eius naturali glutine validiùs operante in &longs;uperfi­cieculis particularum &longs;alium.

SEd huic difficultati re&longs;pondeo, non ab impetu aqu&ecedil; agitatæ, &longs;ed ab alia longè diuer&longs;a cau&longs;a grauio­res particulas innatantes &longs;u&longs;tineri po&longs;&longs;e. Certum e&longs;t corporum particulas quò tenuiores, & minutiores &longs;unt, eò tardiùs per fluida de&longs;cendere, vt contingit in puluere terre&longs;tri in aere, vel aqua di&longs;per&longs;o, qui&atail; nimirùm in hi&longs;ce corpu&longs;culis exiguis eorum &longs;uper&longs;i­cies externa &longs;emper magis, ac magis cre&longs;cit in re­&longs;pectu ad &longs;uam grauitatem, vt alibi declarauimus; quia verò men&longs;ura impedimenti fluidi externi auge­tur, prout pr&ecedil;dicta &longs;uperficies cre&longs;cit cum nullum cor­pus per fluidum moueri queat, quin &longs;ucce&longs;&longs;iuè è loco anteriori fluidum ei contiguum expellat, quotie&longs;­cumque vis impul&longs;iua grauitatis minuitur pro molis diminutione, &longs;uperficies verò in multo minori &longs;cili­cèt &longs;ubduplicata proportione diminuitur, &longs;equitur, vt fluidi impedimentum minus decre&longs;cendo, du&mtail; impetus grauitatis valdè minuitur, tandem ad æqua­litatem, & æquilibrium quamproximè accedant, & proindè hoc nomine particulæ minimæ fluido graui­ores motu &longs;emper tardiori in ip&longs;o de&longs;cendent quo magis eorum moles imminuitur.

Cap. 7. d&etail; natura flui­ditatis.

Prætereà quia experientia con&longs;tat fluidi partes glutine aliquo necti inter&longs;e debere, vt po&longs;tea fusè declarabitur, atque vis, & energia prædicti glutinis &longs;it certi ac determinati gradus, huic verò contrapo­nitur energia grauitatis, & velocitatis, quæ &longs;emper magis, ac magis imminui pote&longs;t, prout moles eius &longs;ubdiuiditur, hinc fit vt tandem ad eam exiguitatem vis grauitatis, & impetus redigatur, vt æquari præ­cisè po&longs;&longs;it energiæ glutinis ip&longs;ius fluidi, proindeque vna alteri præualere nequeat, vnde æquatis viribus, factoque æquilibrio nece&longs;&longs;ariò particulæ illæ graues in ip&longs;o fluido innatantes in eodem &longs;itu quie&longs;cere de­bent. Hac ratione fieri pote&longs;t, vt minim&ecedil; &longs;alis parti­culæ per aquam di&longs;per&longs;æ, & innatantes æquilibrari, & quie&longs;cere in ip&longs;a aqua po&longs;&longs;int, proindeque aqu&atail; &longs;emper &longs;al&longs;edinem retinere valet.

PROP. CLIII.

Vehem entis&longs;ima aquæ ebullitio, quæ in di&longs;&longs;olutione calcis apparet, pendet non ab inte&longs;tino mtu aquæ, &longs;ed ab eius grauitate di&longs;&longs;oluente, & exprimente igneas particulas, quæ in calce contine­bantur.

IN calce po&longs;tea intra aquam demer&longs;a alia noua cau­&longs;a feruoris oritur, quia in exiguis calcinati &longs;axi poro&longs;itatibus, in eiu&longs;que anfractibus includuntur in­numeræ particulæ ignis ibidem in&longs;inuatæ à feruenti&longs;­&longs;imo ardore ornacis, cùmque aqua &longs;uo pondere, &

&longs;&longs;uxibilitate particulas calcis di&longs;&longs;oluendo vinculaque relaxando, apertis o&longs;tiolis egre&longs;&longs;us concedatur igneis illis corpu&longs;culis, quæ po&longs;tea expre&longs;&longs;a ab excedenti aquæ pondere velociori motu &longs;ursùm per aquam a&longs;cen­dunt, proindeque in tran&longs;itu bullularum ignearu&mtail; aquæ partes laterales celeriùs, & vehementiùs agi­tantur.

Cap, 7. de natura flui­ditatis.

PROP. CLIV.

Idip&longs;um verificatur in di&longs;&longs;olutione metallorum ab aqua forti.

IDip&longs;um eadem ferè ratione producit aqua fortis, vel regia in metallis, dum enim intra illius poro­&longs;itates vi ponderis eius in&longs;inuatur, &longs;alibus quibus a­qua fortis referta e&longs;t, veluti talis, ac &longs;calpris abradit &longs;olidas aliquas metalli particulas, &longs;imulque relaxat o&longs;tiola, egre&longs;&longs;umque concedit materiæ igneæ ibidem contentæ, quæ expre&longs;&longs;a ab in&longs;igni grauitate aquæ for­tis veloci&longs;&longs;imo motu per eamdem aquam &longs;ursùm a&longs;cen­dit inclu&longs;a in ampullis exiguis, & copio&longs;i&longs;&longs;imis, quæ ebullitionem feruentem producunt, vnà cum ingenti aquæ agitatione; quæ omnia immeritò ab inte&longs;tin&atail; partium aquæ fortis agitatione qui&longs;quam effici cen­&longs;eret, cùm ad&longs;it nece&longs;&longs;aria, & euidenti&longs;&longs;ima cau&longs;&atail; nempè &longs;implex grauitas aquæ fortis, quæ e&longs;t impo&longs;­&longs;ibile vt intra poro&longs;itates inanes, aut à leuiori cor­pore oppletas, non in&longs;inuetur, & proinde in eius motu impetum non concipiat, cuius virtute exiguæ metalli particulæ corrodantur, exprimaturque ma­teria ignea in eo contenta, proindeque vehementiùs aqua agitetur, & tandem à vi eiu&longs;dem impetus parti­cul&ecedil; minimæ metalli, licèt aqua grauiores &longs;int, po&longs;&longs;unt hinc inde di&longs;pergi, tran&longs;portarique, & extincto fer­uore à naturali partium aquæ vi&longs;co&longs;itate retineri in media aqua po&longs;&longs;unt, quotie&longs;cumque vis re&longs;i&longs;tentiæ aquæ æqualis &longs;it exili&longs;&longs;imo ponderi earumdem par­ticularum metallicarum.

Cap. 7. d&etail; natura flui­ditatis.

Aliquæ ­peri&etilde;tiæ no­&longs;træ &longs;enten­riæ refragati videntur, qui­bus inf&longs;atisfacie­mus.

Hic po&longs;&longs;ent innumera ph&ecedil;nomena afferri, quæ in prædictis di&longs;&longs;olutionibus &longs;alium mineralium, & ve­getabilium ob&longs;eruantur, vt nimirùm cùm calx, aut metallum non demergitur intra aquam, &longs;ed eminet, tangitque dumtaxat &longs;uperficiem eius externam, & nihilominùs aqua a&longs;cendit, &longs;ubleuaturque penetran­do &longs;alis, & metalli poro&longs;itates, & po&longs;tea denuò de­&longs;cendendo di&longs;perguntur &longs;olidæ particulæ efficiunt­que vniuer&longs;am aquam &longs;apidam, vel metallo impr&ecedil;­gnatam; non minùs videmus aquam per fi&longs;tulas tenui&longs;­&longs;imas, per &longs;pongias aquam contingentes &longs;upra eius &longs;uperficiem, a&longs;cendere. Vnde qui&longs;piam dubitandi an&longs;am arripere po&longs;&longs;et, non pendere has operationes à vi grauitatis, quæ naturæ ductu non &longs;ursùm, &longs;ed deorsùm impellere aquam fluidam pote&longs;t.

Sed interim ex demon fratis euidter reijitur oppo&longs;ita sen­tentia.

Sed hoc non o&longs;&longs;icit doctrinæ &longs;uperiùs expo&longs;itæ, nam in &longs;pongia, pumice, &longs;ale, calce &c. intra aquam de­mer&longs;is nece&longs;&longs;ariò vis grauitatis fluidi prædictas ope­rationes efficit, hæ verò diuer&longs;æ operationes paritèr

producuntur ab eodem principio grauitatis, vt in-feriùs o&longs;tendemus, patebitque nece&longs;&longs;itate quadam mechanica à grauitate, & momento aquæ fluidæ eam in&longs;inuari intra eleuatas fi&longs;tulas, vel intra &longs;pongiarum, & &longs;alium eminentes poro&longs;itates. Vnde elicere po&longs;­&longs;umus, quòd ex prædicto motu fermentationis dedu­cinon pote&longs;t, quòd in fluido partes cius perpetuò in­te&longs;tino motu agitentur, à qua commotione fluidi­tas efficiatur, & ab hac veluti à ca, di&longs;&longs;olutiones &longs;alium metallorum, &c. non dependeant.

Cap. 8.

Cap. 7. d&etail; natura flui­ditatis.

Deinde expendenda e&longs;t præcipua figura particu­larum aquam componentium iuxtà Carte&longs;ij mentem. Putat enim prædictas particulas oblongas virgulas flexibiles, & lubricas e&longs;&longs;e, vti &longs;unt anguillæ, quæ va­rijs modis contortæ &longs;e mutuò amplexentur, & con­ponant aggeriem nodo&longs;am, in qua varijs modis com­plicatæ excurrunt, varièque flectuntur, & &longs;ic flui­ditatem aquæ componere, atque efficere. Et hinc ra­tionem eliciunt, quare guttæ aquæ è &longs;upremis arbo­rum ramis, ac folijs pendentes non decidunt, &longs;ed te­naci quodam vinculo retinentur, hocque confirmare nituntur tali exemplo; multotiès è ca&longs;ei fragmento &longs;ursùm eleuato, & ab eius prona facie pendet agge­ries plurimorum vermium, qui nedùm non decidunt deorsùm, &longs;ed componunt veluti quamdam gibbo&longs;i­tatem deorsùm pendentem, dum tamen prædicti ver­mes miris modis agitantur, & inflectuntur.

Ex Carteo aquæ parti­culæ &longs;ut ob longæ, flexi­biles, vt an­guillæ, per­petuò agita­ræ, & hinc gnttas aquæ pendulas &longs;u­tineri po&longs;&longs;e cen&longs;et.

Cap. 7. dnatura flui­ditatis.

PROP. CLV.

O&longs;tenditur ab&longs;urditas talis po&longs;itionis Carte&longs;ianæ.

AT &longs;i talis e&longs;t aquæ natura, &longs;equitur vt eius par­ticulæ &longs;int animatæ, oportet enim vt percipi­ant, & eligant motus, & inflexiones, quæ nece&longs;&longs;ari&ecedil; &longs;unt ad prædictum effectum producendum. Nam &longs;i­cuti illi vermes nece&longs;sè e&longs;t vt partim in&longs;inuentur i&ntail; &longs;upremas ca&longs;ei poro&longs;itates non directè, &longs;ed tortuosè capita inflectendo, vt nimirùm efficiant hamos, vel vncinos, & è contrà infimæ partes vermium penden­tes debent quoque inflecti, vt alios vncinos efforment, in quibus &longs;ub&longs;equentes vermes adrepant, debent­que paritèr &longs;ub&longs;equentes vermes non &longs;ecùs incurua­ri, vt duplices vncinos componerent in eius extremita­tibus. idip&longs;um efficere deberent anguillæ illæ aquam componentes. At quomodo per&longs;euerare po&longs;&longs;et ag­geries prædictarum aquæ anguillularum, ni&longs;i prædi­ctæ earum curuitates &longs;umma &longs;olertia, & prouidentia fierent, & per&longs;euerarent, prout nece&longs;&longs;itas &longs;u&longs;tentatio­nis ponderis earumdem exigit. Et &longs;i non prouiden­tia, &longs;ed ca&longs;u, vt con&longs;entaneum e&longs;t; monentur, quomo­do po&longs;&longs;ent perpetuò agitari, & inflecti quin aliquan­do vncini illi di&longs;&longs;oluti &longs;e mutuò non retinerent? vide­tur enim impo&longs;&longs;ibile vt vniuer&longs;a ma&longs;&longs;a virgularu&mtail; aquæ aliquando, &longs;altem per breue tempus non diri­gatur, vel &longs;altem diuer&longs;o modo flectatur, quàm opus e&longs;t, vt continuata &longs;eries hamorum, vel vncinorum &longs;e vici&longs;&longs;im &longs;u&longs;tinentium non e&longs;formetur, & &longs;ic fieri po&longs;­&longs;et vt tota gutta aquæ pendens, aut aliqua eius por­tio &longs;olutis vinculis, directi&longs;que vncinis deorsùm la­beretur, quod tamen e&longs;t fal&longs;um. Tandem &longs;i attentè con&longs;ideretur &longs;tructura animalium optimè percipitur non po&longs;&longs;e vermem inflecti, ac con&longs;eruari in aliquo &longs;i­tu curuo ab&longs;que vi, & tractione mu&longs;culorum, vt ni­mirùm eorum fibræ decurtentur relaxatis fibris con­trapo&longs;iti mu&longs;culi. hoc autem quàm &longs;it durum, & in­comprehen&longs;rbile in particulis ip&longs;ius aquæ &longs;uppone­re vnu&longs;qui&longs;que per &longs;e videt. Si igitur &longs;aluari pote&longs;t aquæ fluiditas, & tenacitas illa, qua guttæ penden­tes retinentur faciliori, & euidenti po&longs;itione, vt mox patebit, quis quæ&longs;o præeliget hanc violentam, diffi­cilemque hypothe&longs;im? nulla igitur e&longs;t nece&longs;&longs;itas po­nendi formam, & motionem partium aquæ tam ab­&longs;urdam incomprehen&longs;ibilenque vt facultates, & in&longs;tru­menta eadem, vel analoga ijs, quæ in animalibus natu­ra efformauit, ponantur.

Cap 7. d&etail; natura flui­ditatis.

PROP. CXLVI.

Fluida aquea habere vi&longs;co&longs;itatem aliquam, quæ &longs;aluari non pote&longs;t ab&longs;que machinulis flexibilibus, & re&longs;ilien­tibus, à quibus aquæ particulæ, veluti lanu­gine ambiuntur.

PO&longs;tremo loco dicendum e&longs;t de alia fluidi pa&longs;&longs;io­ne, quæ in exiguis eius partibus ob&longs;eruatur, non autem in grandioribus; con&longs;tat enim experientia aquam, & cætera fluida naturam quamdam glutino­&longs;am, & vi&longs;co&longs;am habere, quod quidem euincitur ex eo quod guttæ fluidæ &longs;u&longs;pen&longs;æ pendent è &longs;upremis ramis arborum, & &longs;i quis velit particulam eiu&longs;dem guttæ à reliqua eius ma&longs;&longs;a diuellere, per&longs;entiet re&longs;i­&longs;tentiam aliquam, & ce&longs;&longs;ante viexterna denuò gutta &longs;ponte recolligitur; quòd verò prædicta operatio pendeat à glutine, con&longs;tat ex eo, quòd &longs;i aquæ puri&longs;­&longs;imæ addatur mi&longs;ceaturque &longs;uccus, vel ma&longs;&longs;a aliqua glutino&longs;a, & vi&longs;co&longs;a, tunc quidem guttulæ penden­tes amp&longs;iores fiunt, in fila tenui&longs;&longs;ima &longs;atis longa ex­tenduntur, atque in membranas gracili&longs;&longs;imas attenu­antur quoties in&longs;ufflato aere efficiuntur bullæ ingen­tes, quas pueri efformare &longs;olent. Sic videmus &longs;aliuam vi&longs;co&longs;am, vel aquam cum albugine oui, vel &longs;aponi admixtam extendi in tenui&longs;&longs;ima fila, & denuò recol­ligi, qui effectus procùl dubio illi vi&longs;co&longs;itati admix­tæ tribui debet. Si igitur tam in&longs;ignis effectus pro­ducitur à grandi copia glutinis, vel humor is vi&longs;co&longs;i, quis dubitabit eumdem effectum quando e&longs;t minùs in&longs;ignis productum fui&longs;&longs;e à minori copia eiu&longs;de&mtail; glutinis, & vi&longs;co&longs;i humoris? Sed nemo ferè dubitat in aqua, & in reliquis fluidis vi&longs;co&longs;itatem, aut quid analogum glutini in exi&longs;tere, dubitatur &longs;olummodò de cau&longs;a prædicti glutinis, cùm hæc po&longs;&longs;it e&longs;&longs;e exter­na, & interna, duo enim corpora vniri po&longs;&longs;unt, & re­&longs;i&longs;tere &longs;eparationi, cùm à cau&longs;a externa impelluntur vnum versùs aliud, vel potiùs ab aliqua vi motiua, qualis e&longs;t illa, quæ in magnete, & magneticis corpo­ribus ob&longs;eruatur. Sed hæc inferiùs refellentur. alij po&longs;tea recurrunt ad figuras hamatas, & vncinatas corporum gluten componentium. Sed meo iudicio videntur huiu&longs;modi curuitates, & vncinos per &longs;&etail; minimè vi&longs;co&longs;itatem efficere po&longs;&longs;e, quia po&longs;tqua&mtail; actu vncini, & hami illi di&longs;&longs;oluti, & disiuncti &longs;unt, nullam vim haberent &longs;e &longs;e denuò recolligendi, & vni­endi; po&longs;&longs;et profectò hoc effici &longs;i prædict&ecedil; hamatæ fi­guræ e&longs;&longs;ent flexibiles, & re&longs;ilientes, vt machinæ, & arcus, qui po&longs;tquam di&longs;tracti &longs;unt, vim habent &longs;e con­trahendi. Quod verò particulæ fluidi machinæ na­turam participent, confirmatur ex eo, quòd fluid&atail;, quæ rigida, & dura reddi po&longs;&longs;unt, po&longs;t refrigeratio­nem flecti po&longs;tea, & re&longs;ilire, & dirigi &longs;ponte videmus, cum &longs;umuntur graciles laminæ prædicti corporis in­durati, vt patet inglacie, vitro, ferro, &c. Quòdque præterea veri&longs;imilis &longs;it prædicta po&longs;itio machinula­rum in fluidis, patet exemplo aeris, qui reuerà com­ponitur ex particulis re&longs;ilientibus ad modum machi­næ, vt &longs;uperiùs o&longs;ten&longs;um e&longs;t, igitur non erit impo&longs;&longs;i­bile, vt eamdem naturam fluida den&longs;iora participent, &longs;cilicèt con&longs;tent ex ij&longs;dem machinulis, alitèr tame&ntail; efformatis, quàm in aere. Verum tamen e&longs;t, quòd prædictæ machinulæ in aqua, & &longs;imilibus fluidis de­bent e&longs;&longs;e valdè &longs;uperficiales, veluti lanugo quædam tenuis, & debilis inue&longs;tiens quodlibet aquæ mini­mum, &longs;cilicèt concipi debet interna, & indiuidu&atail; quælibet aquæ particula &longs;olida, & dura, cuius figura &longs;it octacdra, vel alterius fimilis figuræ; hæc, inquam, extrin&longs;ecè ambiri debet à tenui&longs;lima lanugine, quæ flecti, & re&longs;ilire po&longs;&longs;it ad modum machinæ. Sed opor­tet vt prædictæ machinulæ &longs;int breues, contortæ, & exigui roboris, vt nimirùm minimam, & in&longs;en&longs;ibilem vim habeant, nec po&longs;&longs;int impedimentum &longs;en&longs;ibil&etail; a&longs;ferre fluxui interno earumdem partium aquæ.

Cap. 7. dnatura flui­ditatis.

In libpercu.

Cap. 7. d&etail; natura flui­ditatis.

Cap, 7. d&etail; natura flui­ditatis.

Sed circa vim prædicti glutinis fluidi nonnullæ dif­ficultates occurrunt. prima quomodo, & quare par­tes fluidi facilè &longs;uper &longs;e ipfas excurrere po&longs;&longs;int, diffi­cilè verò à tota ma&longs;&longs;a fluida diuelli, &longs;egregariqu&etail; valeant. &longs;ecunda, quare lamina &longs;olida, quæ in&longs;en&longs;ibi­litèr magis, vel minùs grauis fit, quàm fluidum, deor­sùm, aut fursùm a&longs;cendere po&longs;&longs;it in ip &longs;omet fluido, ex quo deducunt nullam vi&longs;co&longs;itatem in ip&longs;o fluido re­periri. tertia quare aliqua fluida non mi&longs;centur, imò fugiunt alia fluida, & &longs;olida corpora, vti aqua no&ntail; mi&longs;cetur cum aere, neque cum oleo, neque cum hy­drargyro, & quodlibet ex prædictis corporibus &longs;eiun­gitur, & refugit reliqua corpora; quæ &longs;ibi analog&atail; non &longs;int.

Proponun­tur difficul­tates aliquæ circa vim glutinis flui­dorum.

PROP. CLVII.

Quare partes fluidi &longs;uper &longs;eip&longs;as fluere po&longs;sit, difficilè verò à tota ma&longs;&longs;a fluida pen­dula diuelli, di&longs;iungique qucant, rationem reddere.

QVoad primam videtur machina eius naturæ e&longs;­&longs;e, vt tantò maiorem energiam, autre&longs;i&longs;tenti-am habeat, quantò à maiori violentia di&longs;trahatur, vt con&longs;tat experientia, &longs;i enim arcus caly beus violenti&longs;&longs;i­mè &longs;lectatur, vel dilatetur, videmus quòd &longs;emper ma­gis, ac magis re&longs;i&longs;tit di&longs;tractioni maiori, & validiori energia, quò magis ex plicatur, vel inflectitur machi­na; &longs;ed quia partes aquæ connectuntur ad inuice&mtail; &longs;uperficietenùs ob iam dictam lanuginem, fit vt quo­tie&longs;cumque diuellere tentamus vnam aquæ parte&mtail; ab alia, tunc prædictæ machinulæ lanuginem com­ponentes inter &longs;e connexæ violenter di&longs;trahantur; & proindè maiorem re&longs;i&longs;tentiam habeant, quàm partes eiu&longs;dem aquæ, quæ &longs;implici contactu &longs;olummodò vni­untur ab&longs;que eo, quòd eorum machinulæ di&longs;tractionem patiantur; vnde fit vt minori tenacitate connectan­tur, & ideò ob flexilitatem extremarum partium di­ctæ lanuginis facilè vna aquæ pars &longs;uper alteram mo­ueri, & fluere po&longs;&longs;it: quia vero actus, & operatio ip&longs;a diuul&longs;ionis aquæ ab aqua &longs;ecum inuoluit violenta&mtail; machinularum aquæ di&longs;tractionem, non item fluxus aquæ per aquam, hinc &longs;equitur vt in di&longs;tractione, & diuul&longs;ione re&longs;i&longs;tentia percipiatur, non verò in fluxu e­iu&longs;dem aquæ &longs;uper reliquas eius partes. Similiter in gutta pendente particulæ minimæ aquæ &longs;uperficiem eius extrin&longs;ecam componentes, mutuò &longs;e connectunt, vinciunturque, connexis nempe machinulis à quibus aquæ particulæ ambiuntur, veluti à lanugine quadam, vt dictum e&longs;t; quia verò prædictæ partes externæ &longs;u­&longs;tinent, ne dùm pondus proprium, &longs;ed etiam grauita­tem omnium partium internarum eiu&longs;dem guttæ, & proindè omnium maximè comprimuntur, fit vt præ­dictæ machinulæ externæ maximè di&longs;trahantur, ex­tendanturque, & &longs;ic efficiant veluti reticulum te­nax, & con&longs;i&longs;tens, internæ verò partes guttulæ quia minus pondus &longs;u&longs;tinent immo &longs;u&longs;tinentur à reticulari prædicta &longs;uperficie externa aquæ, & no&ntail; vniuer&longs;am ponderis vim patiuntur, vti externæ par­tes, ideò minùs, quàm externæ machinulæ di&longs;trahun­tur, & propterea debiliori tenacitate &longs;e mutuò nec­tunt, & hinc fit vt altera &longs;uper alteram excurrere fa­clè po&longs;&longs;it, vt con&longs;tat experientia, videmus enim in­ternas guttulæ partes vago motu agitari fluereque.

Cap. 7. d&etail; natura flui­ditatis.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CLVIII.

O&longs;tenditur aquam vi glutinis parumper re&longs;istere penetrationi corporum &longs;oli­dorum per eam di&longs;currentiu.

CIrca &longs;ecundam, dici pote&longs;t, quòd reuerà adfit pu­&longs;illa aliqua re&longs;i&longs;tentia cum dura lamina fluidum penetrat, & confricat laterales partes eius, quæ re&longs;i­&longs;tentia ob &longs;ui exiguitatem conuincinon pote&longs;t ab ex­perimentis aliquorum. Et profectò &longs;i reuerà nulla&mtail; vi&longs;co&longs;itatem fluidum haberet, nil omninò penetratio­ni alterius corporis refi&longs;teret, & ideò quodlibet cor­pus grauius &longs;pecie quàm aqua in ea de&longs;cenderet, & quodlibet minus graue &longs;pecificè a&longs;cenderet &longs;ursùm, neque exce&longs;&longs;us perimetri, aut &longs;uperficiei corporis de­mer&longs;i re&longs;pectu grauitatis eius po&longs;&longs;et omninò prohi-bere de&longs;cen&longs;um, vel a&longs;cen&longs;um in aqua, &longs;ed &longs;olum­modò tarditatem afferret, non autem quietem ab&longs;o­lutam, vt fatentur Ghetaldus, Steuinus, & alij. Modò minuti&longs;&longs;ima grana terrea, &longs;alium, metallorum, & non minùs particulæ minimæ corporum leuiorum ligni, aeris, &c. licèt habeant excedentem, & grandem &longs;u­perficiem re&longs;pectu pu&longs;illæ grauitatis eorum non ta­men po&longs;&longs;ent omninò quie&longs;cere in medio aquæ, &longs;ed len­ti&longs;&longs;imo motu a&longs;cenderent, vel de&longs;cenderent, vt exigit exce&longs;&longs;us, vel defectus grauitatis &longs;pecificæ corpu&longs;cu­lorum demer&longs;orum à grauitate fluidi aquei; &longs;ed hoc e&longs;t fal&longs;um, metalla enim, &longs;ales, & aer in minuti&longs;&longs;im&atail; granula redacta immobilitèr in medio aqu&ecedil; quie&longs;cunt, & ibidem per&longs;euerant, igitur falfum e&longs;t aquam gluti­ne omnino priuari, & nil prorsùs penetrationi re&longs;i&longs;te­re;erit igitur aliquanti&longs;per aqua glutino&longs;a, habebitque &longs;altem aliquam pu&longs;illam; & &longs;uperficialem vi&longs;co&longs;ita­tem. Adde quòd partes intermediæ fluidi cùm &longs;int æquilibratæ atque &longs;u&longs;tine antur exiguam compre&longs;&longs;io­nem creant, & proindè machinulæ &longs;uperficiales par­ticularum aquæ &longs;ubiectæ non po&longs;&longs;unt valde di&longs;trahi, vel con&longs;tringi, & &longs;ic minimam vim re&longs;ilientem exer­cere po&longs;&longs;unt.

Cap. 7. d&etail; natura flui­ditatis.

Sed dices, &longs;r aquæ particulæ à prædicta lanugin&etail; ambiuntur, ergo aqua non minùs quàm aer conden&longs;a­ri deberet quod repugnat experientiæ. Re&longs;pondeo quòd prædicta lanugo valdè exigua e&longs;t re&longs;pectu in­ternæ &longs;oliditatis cuiu&longs;libet globuli aquei, & &longs;ic no&ntail; negatur quòd aliquanti&longs;per aqua conden&longs;ari, con&longs;ti-parique po&longs;&longs;it, tamen ob inperceptibilem paruitatem &longs;en&longs;um fugit.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CLIX.

Aquam conden&longs;ari paramper ob cedentiam lanuginicius experimento probatur.

ET hoc &longs;atis concinnè confirmari po&longs;&longs;e videtur à præclaro experimento facto in aula Sereni&longs;&longs;imi M. D. Hetruriæ is iu&longs;&longs;it (vt mihi relatum fuit) caua&mtail; pilam argenteam aqua repleri, atque exacti&longs;&longs;imè clau­di, ac ferruminati, quæ po&longs;tea graui malleo contu&longs;&atail; priorem &longs;phæricitatem ami&longs;it, proindeque internum eius &longs;patium euidenti contractione diminutum fuit, cùm con&longs;tet figurarum i&longs;operimetrarum &longs;phæram e&longs;&longs;e omnium capaci&longs;&longs;imam, nece&longs;sè ergo fuit vt moles a­quæ, quæ priùs ingens &longs;patium &longs;phæricum replebat, aliquo pacto &longs;tringeretur angu&longs;tareturque, tunc mi­rabile &longs;pectaculum &longs;e obtulit, nimirùm vndique pila argentea ex&longs;udare cæpit effundendo exiguos globu­los aqueos &longs;imiles illis, qui in cute no&longs;tra dum &longs;uda­mus apparere &longs;olent. Ga&longs;&longs;endus po&longs;tea refert in &longs;imi­li pila contu&longs;a po&longs;tquam exiguum foramen aperui&longs;­&longs;et, longiùs aquam pro&longs;ilientem eieci&longs;&longs;e. Ex his om­nibus videtur elici po&longs;&longs;e aliquanti&longs;per aquam ant&etail; ex&longs;udationem, aut eiectionem conden&longs;atam fui&longs;&longs;e.

Et licèt re&longs;ponderi po&longs;&longs;et, vas prædictum po&longs;t con­tu&longs;ionem violentèr &longs;e di&longs;tendi&longs;&longs;e, & dilata&longs;&longs;e laterali­tèr, & hac ratione capacitatem eius auctam &longs;upplere potui&longs;&longs;e con&longs;trictionem factam à contu&longs;ione, & vio­lentam di&longs;tractionem illius laminæ argenteæ ad mo­dum machinæ &longs;e re&longs;tringendo facilè potui&longs;&longs;e effluuium illud ad in&longs;tar fonticuli, vel ex&longs;udationem per poros dilatatos efficere; nihilominùs videtur incredibil&etail; in illa violenti&longs;&longs;ima compre&longs;&longs;ione facta in actu per­cu&longs;&longs;ionis aquam ne minimum conden&longs;atam fui&longs;&longs;e &longs;al­tem per breui&longs;&longs;imum empus, quæ conden&longs;atio præ­clarè &longs;aluatur in no&longs;tra po&longs;itione, quia &longs;cilicèt parti­culæ aquæ duri&longs;&longs;imæ ambiuntur veluti à lanugine ma­chinularum flexibilium, quæ parumper po&longs;&longs;unt com­primi, conden&longs;ationemque pati.

Cap 7. d&etail; natura flui­ditatis.

PROP. CLX.

Existentia lanuginis aquæ ab experimento &longs;uadetur.

EX eadem hypothe&longs;i texturæ partium aquæ, & ae­ris reddi pote&longs;t ratio alterius pulcherrimi ex­perimenti. Si enim rotunda phiala vitrea prangu&longs;ti&longs;­&longs;imum eius foramen aqua repleatur, tunc &longs;i ore infe­riùs inuer&longs;o ampulla reuoluatur in aere aqua non de­fluit, at &longs;i po&longs;tea ampullæ orificium vinum (rubru&mtail; commoditatis gratia) contingat in &longs;ubiecto va&longs;&etail; contentum, tunc videbis per idip&longs;um foramen aquam eodem tempore de&longs;cendere, & &longs;imul vinum a&longs;cende­re in tenui&longs;&longs;ima fila extenuatum; & profectò mirabi­evidetur po&longs;&longs;e vinum per medietatem orificij tran&longs;i­e, dum per reliquam medietatem aqua defluit, & hoc n aere &longs;imili modo fieri non po&longs;&longs;e, licèt maiori exce&longs;&longs;u aquæ grauitas aerem &longs;uperet, quam grauitatem vi­ni. At hoc (ni fallor) contingit ex eo quod vinu&mtail; aquæ naturam participat, cum non &longs;it vinum ni&longs;i pu­ra aqua cui immi&longs;centur plures &longs;piritus, & ara, & hacde cau&longs;a facilè pariculæ vini per aquam excurre­re, & fluere po&longs;&longs;unt; at non &longs;ic aer, qui ex grandiori­bus &longs;piris componitur, & propterea mixtionem cum aqua refugit, eiu&longs;que effluuium impedit, quatenus in fundo orificij guttula aquæ pendens qua&longs;r reticulum &longs;uis villis violenter di&longs;tractis efformat; & &longs;ic non fa­cilè po&longs;&longs;unt di&longs;&longs;olui di&longs;gregariqueà grandi oribus ae­ris &longs;piris &longs;imùl pariter inter &longs;e adnexis, intricati&longs;que, & hac de cau&longs;a non pote&longs;t aqua effluere eodem ten­pore quo aer per idem foraminulum a&longs;cendere no&ntail; potè&longs;t.

Cap. 7. d&etail; natura flui­ditatis.

PROP. CLXI.

Eadem lanugo fluidi impedit mi&longs;cellam fluidorum diuer&longs;ænaturæ, & con&longs;i&longs;tentiæ.

AD tertiam dico, quòd reuera ob defectum ana­logiæ non mifcentur aliqua fluida inter &longs;e, ne­que aliqua &longs;olida corpora madefaciunt; at prædict&atail; analogia non con&longs;i&longs;tit in &longs;imilitudine, & &longs;ymmetri&atail; pororum corporis fluidi, nam, vt deinceps dicemus, aqua per aquam penetrare, & fluere pote&longs;t licèt eius pri &longs;int, ob eius exiguitatem, incapaces aquearu&mtail; particularum; igitur vera cau&longs;a (vt puto) quare aqua non mi&longs;cetur oleo, & aeri, e&longs;t quia lanugo extern&atail; aquæ penetrare nequit oleum, velaerem, for&longs;an quia machinulæ pilorum lanuginis aquæ offendunt facie­culas, & lanugines partium olei vel aeris à quibus flectuntur incuruanturque, & &longs;ic à vi machinæ re&longs;ili­entis nedum prohibetur penetratio prædictarum aquæ particularum, &longs;ed in&longs;uper ab inuicem &longs;egregantur. In &longs;olidis verò corporibus &longs;i ad&longs;it incongruentia po­rorum, partes fluidi non madefacient &longs;olidum corpus, vt hydrargyrum lignum non madefaciet, &longs;i verò pori congruentes fuerint tamdiù retardatur mi&longs;cella, & madefactio, quamdiùnon explicatur lanugo particu­larum aquæ quæ in primo occur&longs;u inflexa fuerat. Cau­&longs;a verò, & vis impulfiua, quæ impellit prædictas flui­di particulas intra &longs;olidi poro&longs;itates, po&longs;tea a&longs;&longs;igna­bitur.

Cap 7. d&etail; natura flui­ditatis.

Cau&longs;am inquirere &longs;pontaneæ eleuationis exiguarum aquæ particularum &longs;upra aquæ libellam in ip&longs;o aere.

CAP. VIII.

VEritatem Archimedeæ doctrinæ luculentèr &longs;u­periùs confirmauimus, quod &longs;cilicèt omni&atail; elementaria corpora &longs;iue fluida, fiue con&longs;i&longs;tentia gra­uitatem habent, eamque exercent etiam in proprijs locis, vnde deducitur impo&longs;&longs;ibile e&longs;&longs;e vt aqua v. g. leges æquilibrij tran&longs;grediatur, atque perturbet pul­cherrimum atque admirabilem ordinem, di&longs;po&longs;itio­nemque partium vniuer&longs;i; &longs;cilicèt alterando, atqu&etail; deformando figuram &longs;phæricam, vnde infertur, quòd aquanullo pacto po&longs;&longs;it pendula &longs;u&longs;tineri in medio ae­ris per aliquod tempus, neque poterit eleuari &longs;upra &longs;uperficiem &longs;upremam totius aquæ &longs;ubiectæ, efficien­do nimirùm montuo&longs;itates aqueas, vel &longs;ponte &longs;ua a­&longs;cendendo per cauitates fi &longs;tularum &longs;upra aquæ infi­mam libellam eleuatarum. Et hoc nedùm ip&longs;a ratio per&longs;uadet, &longs;ed etiam &longs;en&longs;us euidentia o&longs;tendit i&ntail; grandioribus aquæ portionibus.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

E contrà videmus in paruis guttulis aquæ, & reli­quorum fluidorum vniuer&longs;alem regulam prædicta&mtail; minimè verificari; aquæ enim guttæ in folijs arborum non intra earum cauitates &longs;tagnantes quie&longs;cunt, ex­plananturque, &longs;ed tumidæ eleuantur vt monticuli, & &longs;phæricam figuram quod ammodò affectare videntur. Similiter aliæ guttæ pendulæ &longs;u&longs;tinentur è &longs;upremis ramis arborum, neque à naturali earum grauitat&etail; deorsùm impelluntur; imò &longs;i prædictæ guttulæ pen­dulæ à contactu digiti, vel fe&longs;tucæ deorsùm leuitèr trahantur, ce&longs;&longs;ante vi externa &longs;ponte &longs;ua aquea ill&atail; mammilla retrahitur &longs;ursum; &longs;imiliter in &longs;i&longs;tulis tenui&longs;­&longs;imis, in &longs;pongijs, atque in filtris manife&longs;tè aqua &longs;pon­te &longs;ua a&longs;cendit &longs;upra libellam aquæ &longs;ubiectæ. Cùm­que doctrina illa vniuer&longs;alis æquilibrij in dubium re­uocari nequeat, nece&longs;sè e&longs;t vt aliæ nouæ cau&longs;æ, quæ in hi&longs;ce guttulis fluidis operantur, efficiant prædictam effectuum diuer&longs;itatem, quam digno&longs;cere èrit ope­ræpretium.

In gttis exguis pertur­barur vni­uer&longs;alis re­gula, qu&atail; fluida vt grauia explari debeant.

Et primo loco inquirenda e&longs;t cau&longs;a, à qua guttæ fluidi &longs;phæricè contornari, eleuari, &longs;u&longs;pendique po&longs;­funt ad &longs;imilitudinem monticuli. Et procùl dubio fa­tendum e&longs;t aquæ guttulas, aut vi naturali, & intrin­&longs;eca &longs;ponte &longs;ua vniri conglobarique, & &longs;ic efficer&etail; &longs;phærulas illas aqueas, vel hoc à violentia aliqu&atail; externa effici. non de&longs;unt vtriu&longs;que &longs;ententiæ fauto­res. Aliqui enim affirmant ab aere ambiente compri­mi aqueas guttulas, vel pondere, vel vi ela&longs;tica ae­ris, aut vtroque modo eas vndique con&longs;tringendo, & con&longs;tipando. Quia verò numquam eædem guttæ aqueæ naturalem grauitatem amittunt, &longs;ed &longs;emper eam exercent; fit vt in exiguis guttulis minima earum grauitas &longs;uperari po&longs;&longs;it à vi compre&longs;&longs;iua aeris. Cùm è contrà in guttis amplioribus vis grauitatis &longs;uperet eiu&longs;dem aeris vim compre&longs;&longs;iuam, & proindè depri­mantur explanenturque in cauitatibus terræ.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXII.

Aeris vis compres&longs;iua non e&longs;t cau&longs;a tumoris rotundi guttularum fluidi.

HÆc profectò &longs;ententia pluribus difficultatibus obnoxia e&longs;&longs;e videtur, quia vt animaduertit ingenio&longs;i&longs;&longs;imus Portius amicus no&longs;ter, vis eiu&longs;de&mtail; aeris compre&longs;&longs;iua vnius, & eiu&longs;dem roboris, & ener­gi&ecedil; e&longs;&longs;e debet, igitur &longs;emper eumdem effectum pro­ducere valet, & proindè quotie&longs;cumque eius actio exercetur contra duas inæquales re&longs;i&longs;tentias, maior, & in&longs;ignior operatio efficietur in &longs;ubiectum minùs re&longs;i&longs;tens, quàm in aliud. Con&longs;iderentur modò duo fluida inæqualitèr grauia &longs;pecie, &longs;cilicèt hydrargy­rum, & aqua communis, certum e&longs;t guttam mercu­rij quatuordecies pondero&longs;iorem e&longs;&longs;e gutta aque&atail; eiu&longs;dem molis, quia verò vis aeris externa compri­menshæc duo fluida &longs;emper eiu&longs;dem roboris e&longs;t, igi­tur non poterit conglobare, & &longs;phæricè contornare guttam mercurij æquè amplam, ac e&longs;t alia gutta aqu&ecedil;; cùm mercurius grauior, & ideò magis re&longs;i&longs;tens requi­rat maiorem vim compre&longs;&longs;iuam, quàm aqua minùs grauis; ergo gutta mercurij, quæ ab eadem energia aeris contornari debet vna pars decimaquarta opor­tet vt &longs;it amplitudinis guttæ aquæ paritèr &longs;phæricè conglobatæ; igitur e&longs;t omninò impo&longs;&longs;ibile vt aer ef­ficiat &longs;phærulam mercurialem grandiorem, quàm a­queam; at quia hoc con&longs;tat experientia, guttæ eniinercurij, quæ &longs;upra tabulam planam &longs;phæricè con­tornantur, agitanturque, non minores e&longs;&longs;e videntur, quàm guttæ aqueæ, quæ &longs;upra bra&longs;&longs;icæ folia conglo­bari &longs;olent: Non erit igitur aeris vis compre&longs;&longs;iua ve­ra cau&longs;a turbinationis aquæ, vel mercurij.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXIII.

Alia experientia id ip&longs;um confirmare.

PRæterea &longs;i energia grauitatis, aut vis ela&longs;tica ae­ris e&longs;t illa, quæ guttas fluidi vndique compri­mendo eas &longs;phæricè tumefacit, igitur illæ guttæ, quæ ab aere rari&longs;&longs;imo, aut infinitè expan&longs;o ambiuntur, minùs comprimi deberent, quàm ab aere copio&longs;o, & maximè conden&longs;ato, igitur in va&longs;e Torricelliano, facto vacuo, vbi nullæ, aut &longs;altèm exili&longs;&longs;imæ aeris particulæ reperiuntur, minùs eleuari, & magis contu&longs;æ e&longs;&longs;e deberent, aut valdè diminutos, & exiguos globulos efficere deberent prædict&ecedil; aqueæ guttulæ à folijs bra&longs;&longs;icæ &longs;u&longs;tentatæ, quàm illæ, quæ ab aere valdè conden&longs;ato ope follium, vel in&longs;trumen­ti pneumatici in aliquo va&longs;e, quod tamen fal&longs;i&longs;&longs;imum e&longs;t, &ecedil;què enim tumidæ &longs;phæricè &longs;u&longs;penduntur, & ad eandem altitudinem, & magnitudinem eleuantur gut­tæ aqueæ in vacuo Torricelliano ab aere rari&longs;&longs;imo, quàm ab aere valdè den&longs;o, & con&longs;tipato, vt in Aca­demia experimentali Medicea experti &longs;umus.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXIV.

Vt partes elementi aquæ &longs;phæricè circa centrum torr con­tornentur, oportet vt vires motiuæ earum versùs cen­trum non &longs;int &longs;emper inter &longs;e æquales, &longs;ed ha­beant eamdem proportionem quam ea­rum diftantiæ à centro.

AD hæc poterit euidenti demon&longs;tratione (ni&longs;i fallor) euinci aqueas guttas non conglobar&longs;phæricè à vi externa aeris compre&longs;&longs;iua. Si enim per­pendamus, quare vniuer&longs;um aquæ elementum circ&atail; centrum sy&longs;tematis elementaris &longs;phæricè congloba­tur, percipiemus hoc effici quia partes aquæ habent vim &longs;emouendi directè versùs centrum terræ, e&longs;tque talis vis motiua in eodem corpore homogeneo aquæ non &longs;emper eiu&longs;dem gradus, ni&longs;i cùm partes exter­næ à centro terræ æquè recedunt.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Sit ergo punctum E centrum globi terraquei, & &longs;upponamus aquam ABCD inæqualitèr di&longs;tare à cen­tro E, &longs;cilicèt à vi externa, v. g. &longs;it eleuatus mons a­queus MAK &longs;upra reliquam eius &longs;uperficiem &longs;phæri­cam BCD. & &longs;iquidem vis

motiua deorsùm |impellens versùs centrum E e&longs;&longs;et eiu&longs;­dem energiæ in aqua A, atque in B, non po&longs;&longs;et deprimi &longs;u­prema aqua A deorsùm, ex­pellendo, & &longs;uperando re&longs;i­&longs;tentiam aquæ B, vel D, quia nimirùm potentia æqualis in æqualem minimè agere pote&longs;t. Nece&longs;sè ergò e&longs;t vt aqua eleuata MAK maiorem vim compre&longs;&longs;iuam habeat, quam aqua B: e&longs;tque hoc euidenti&longs;&longs;imum, quia moles aquæ EA, quæ altior, copio&longs;ior, & ideò grauior e&longs;t, &longs;upera­bit re&longs;i&longs;tentiam minùs eleuatæ aquæ EB, & minoris molis; Igitur vera cau&longs;a, quare elementum aquæ cir­ca centrum terræ &longs;phæricè contornatur, e&longs;t, quia par­tes aquæ cum reliquis continuatæ magis à centro terræ eleuatæ, maiorem vim compre&longs;&longs;iuam habent, quàm ali&ecedil; partes minùs à prædicto centro recedentes.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXV.

Sicirca centrum orbis elementaris duæ fluidæ &longs;phæræ concen­tricæ collocentur, quarumexterior grauis &longs;it, non verò interior, quæ habeat montuo&longs;itatem aliquam, compres&longs;io vniuer&longs;alis fluidi ambientis non poterit montuo&longs;itatem contenti fluidi contundere.

SVpponamus modò mercurium ABCD non habe­re vim &longs;e &longs;e vniendi, &longs;cilicèt non habere graui­tatem, patet quòd &longs;i prædictum hydrargyrum pone­retur circa centrum E totius regionis elementaris &longs;ponte &longs;ua non e&longs;&longs;iceretur &longs;ph&ecedil;­

ricum, &longs;ed retineret eamdem montuo&longs;itatem MAK. Sup­ponamus po&longs;tea mercurium à &longs;phæra aeris FGHI circun­dari, & habeat prædictu&mtail; fluidum ambiens grauitatem, & principium motiuum ver­sùs centrum eius E, & proin­dè ma&longs;&longs;a mercurialis ABCD vndique comprimetur à fluido ambiente FGHI; &longs;itque prædictum fluidu&mtail; &longs;ibi homogeneum, &longs;cilicèt &longs;it vniformitèr graue. Dico quod ambiens fluidum nulla ratione mercuriu&mtail; ABCD &longs;phæricè contornabit; quia fluidum ambiens comprimit comprehen&longs;um fluidum præcisè, quantum exigit men&longs;ura grauitatis eius; e&longs;t verò grauitas flui-di FA ad grauitatem alterius partis BG vt altitudo, &longs;eu moles illius ad huius molem (cum &longs;upponatur fluidum &longs;ibi ip&longs;i homogeneum) & e&longs;t moles fluidi FA minor, quàm GB, igitur fluidum FA minùs grauitat, & ideò minùs comprimit &longs;ubiectum fluidum AE, quàm fluidum GB comprimat &longs;ibi &longs;ubiectum fluidum EB; &longs;ed e&longs;t impo&longs;&longs;ibile vt minor vis compre&longs;&longs;iua flui­di ambientis FA impellat deorsùm, & contundat mon­tuo&longs;itatem fluidi MAK, quin expellatur &longs;ursùm hu­milior pars eiu&longs;dem fluidi EB; & hæc &longs;ursùm expelli nequit ni&longs;i cædat vis compre&longs;&longs;iua grauitatis totius fluidi GB, igitur deberet vis grauitatis maior totius aquæ BG &longs;uperari à potentia minoris grauitatis FA, quod e&longs;t impo&longs;&longs;ibile, ergò vis compre&longs;&longs;iua extern&atail; aeris, vel cuiuslibet alterius fluidi, non pote&longs;t effice­re tumorem illum &longs;phæricum, quem in guttis mercu­rij, & aquæ ob&longs;eruamus, quotie&longs;cumque prædictæ guttæ grauitate carerent, & in centro regionis ele­mentaris collocatæ e&longs;&longs;ent.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXVI.

Non po&longs;&longs;e guttulas fluidi &longs;phæricè conglobari ab vniuer&longs;ali ambientis aeris compres&longs;ione demonstratur.

RE&longs;tat modò vt idip&longs;um o&longs;tendamus in guttis a­queis in &longs;uperficie no&longs;træ telluris exi&longs;tentibus. Gutta aquea ABCD &longs;u&longs;pen&longs;a &longs;it filo GA, vt pauimen­tum VX non attingat, & &longs;uppo&longs;ito, quòd ab oceano aereo RS vndique gutta &longs;u&longs;pen&longs;a contundatur, & ve-luti forcipe con&longs;tringatur, nempè &longs;upernè à columnis aereis GA, lateralitèr à cylindris GH, & SD & infer­nè à colunnis aereis reflexis RVB, & SXI. Dico ab ae­reo oceano minimè gutta&mtail;

ABCD &longs;phæricè contornari. Quia guttæ aqueç partes AH CD omninò carent vi motiua qua ferantur versùs centrum eiu&longs;dem guttæ, eo quòd pars eius &longs;uprema A trahitur &longs;ur­sum à filo GA, in&longs;ima verò C tendit deorsum vt grauis, ideò du&ecedil; partes oppo&longs;itæ A & C à &longs;e inuicem fugiunt, & proindè potius conantur à centro ‘guttæ’ recedere, quàm ad ip&longs;um ferri, & cum eo vniri; partes verò collaterales H, & D &longs;iu&etail; vim grauitatis exerceant, &longs;iue non, nunquam tamen ho­rizontali motu versùs guttæ centrum naturali in&longs;tin­ctu tendent, ergò &longs;iconcipiatur centrum guttæ ABCD ac &longs;i e&longs;&longs;et centrum &longs;y &longs;tematis elementaris partes gut­tæ cen&longs;eri po&longs;&longs;ent non graues. His po&longs;itis intelliga­tur &longs;uperaddita, vel eleuata eminentia, &longs;eu mammil­la aquea H in laterali loco guttæ, tunc aereus ocea­nus RS ne dum &longs;upernè &longs;uperficiem A, &longs;ed etiam la­tera eius H, D, & infimas facieculas B, C æquali ener­gia comprimet, tum ratione grauitatis, cum ratione virtutis ela&longs;ticæ eius. Habemus igitur ca&longs;um &longs;imilem ei qui in præcedenti propo&longs;itione &longs;upponebatur, &longs;cili­cèt gutta ABCD cuius partes non nituntur vniri, nec &longs;ponte ferri versùs centrum eiu&longs;dem guttæ, & ab ae­re æqualibus viribus vndique comprimitur; quar&etail; e&longs;t impo&longs;&longs;ibile, vt mammilla H contundatur, hoc e­nim, vt dictum e&longs;t, exigit maiorem vim compre&longs;&longs;iuam in H, quàm in D. non poterit ergo prædicta gutta præ­cisè contornari, & acquirere tumorem &longs;phæricum.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Idip&longs;um verificari in guttulis aqueis pauimento innixis, patet ex eo, quòd &longs;altem collaterales partes eius H, & D carent vi motiua horizontali qua feran­tur versùs guttæ centrum, & tunc mammilla H no&ntail; poterit contundi ab aere GH cum eius vis non &longs;it ma­ior vi compre&longs;&longs;iua aeris SD. Vnde colligitur, quòd compre&longs;&longs;io fluidi aerei RSXV nullo pacto globo&longs;ita­tem guttularum aquæ creat, quare fatendum e&longs;t ab alia longè diuer&longs;a cau&longs;a hoc prouenire.

Videndum modò o&longs;t, an à vi intrin&longs;eca, & natu­rali mercurij, vel aquæ prædictæ guttulæ &longs;u&longs;pendan­tur, & tornentur.

PROP. CLXVII.

Guttula fluidæ non po&longs;&longs;unt &longs;ponte à vi intrin&longs;eca, & natu­ralitumorem, & &longs;phæricitatem acquirere.

QVia guttæ fluidæ diuer&longs;is in locis collocari ef­formarique po&longs;&longs;unt, hinc &longs;equitur vt eius par­ticulæ componentes cogantur modò versùs vna&mtail; plagam, modò versùs alteram tendere, ac promoue­ri, prout centrum, aut &longs;u&longs;pen&longs;io guttulæ varijs in lo­cis transferri, ac &longs;ituari pote&longs;t, & tunc &longs;i &longs;en&longs;u carent mirari profectò &longs;ubit à quo Ntio monentur, ei&longs;que o&longs;tenditur, vbi gentium guttæ centrum exi&longs;tat, tran&longs;­portatumque &longs;it, & quo &longs;en&longs;u id a&longs;&longs;equi valeant, & quo appetitu afficiantur, vt eum amplecti velint; po­ni ergo debet vis aliqua, quæ cæca nece&longs;&longs;itate tran&longs;­ferat, retineat, conglutinetque aqueas particulas circa centrum guttulæ &longs;u&longs;pen&longs;æ, hæc autem vis mo­tiua cùm non &longs;it determinata ad aliquam plagam, erit profectò vaga, & incerta, quæ nihilominùs certu&mtail; gradum impetus, & proindè æqualem vim &longs;&etail; mouendi &longs;ursùm, deorsùm, & ad latera habebit, ergo hi&longs;ce omnibus motionibus agitari deberent a­quæ, vel mercurij particulæ in ip&longs;is guttis pendenti­bus, & contornatis, & hoc quidem audactèr aliqui recentiores pronundiant, quorum &longs;ententia (ni fal­lor) non &longs;ecùs, ac præcedens, facilè refelli pote&longs;t, quia &longs;i qu&ecedil;libet pars fluidi in gutta æquali vi, & ener­gia mouetur, &longs;emel alterata, & perturbata eiu&longs;de&mtail; guttærotunditate, &longs;cilicèt exporrecta aliqua mam­milla ex eodem fluido guttam componente, non po&longs;­&longs;et pri&longs;tinam &longs;pli&ecedil;ricitatem denuò acquirere, prop­terea quod pars illa magis à centro remota non po&longs;­&longs;et centro guttæ approximari, ni&longs;i expelleret longiùs à centro reliquas partes in vallibus guttæ exi&longs;tentes, nec hæ cedere locum po&longs;&longs;ent, cùm æqualem energiam, ac vim habeant, ac illæ, quæ in &longs;ummitate mammil­læ degunt. Si verò con&longs;iderentur motus contrarij, & diuer&longs;i quatenùs vna portio ad infimum &longs;itum guttæ deprimitur, altera verò eleuatur, ali&ecedil; lateraliter ferun-tur, tunc quidem quis capiet globo&longs;am, & &longs;phæricam figuram fluidi partes irregularitèr &longs;e mouentes com­ponere po&longs;&longs;e? Finge in hac aula pluuiam copio&longs;a&mtail; granulorum frumenti cadentium, & &longs;imùl infernè ab aliqua violentia grana delap&longs;a repelli &longs;ursùm, & la­teraliter; in hac (inquam) perpetua, & confu&longs;a agi­tatione, quomodò po&longs;&longs;ent prædicta grana deciden­tia, & a&longs;cendentia &longs;ph&ecedil;ricam figuram conflare, & non potiùs quamlibet aliam figuram irregularem, vt ex­perientia con&longs;tat?

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Prop. 365.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Recurrere ad inflexionem particularum mercurij, vel aquæ, qu&ecedil; ad in&longs;tar anguillarum conglobentur, & vniantur, & &longs;ic guttulas pendentes, & &longs;phæricas effi­ciant, videtur omninò ab&longs;urdum, vt &longs;uperiùs in&longs;inua­uimus.

Aiunt ob He­fectum analo­giæ aquam, vol mercurium in­tra aerm &longs;inuarpo&longs;&longs;e, & i­deò motu re flaxo in &longs;&etail; ip&longs;is cooglo­bati.

Tantummodò con&longs;ider abimus ea, quæ ab alijs af­feruntur, qui aiunt ob defectum analogiæ mercurij, vel aquæ cum aere ambiente fieri, vt hydrargyrum, vel aqua aerem effugiat, & aer aquam, & potiùs i&ntail; &longs;e ip&longs;am &longs;pontaneo motu conglobetur, vniaturqu&etail; non quidem à perceptione vtilis electione &longs;ponta­nea, &longs;ed nece&longs;&longs;itate quadam, quæ cogat vt partes fluidæ &longs;e mouentes, & perpetuò agitatæ, dum in ae­re moueri nequeunt, reflectantur intra &longs;e ip&longs;as, & &longs;ic

guttulas illas &longs;phæricas efforment. A&longs;&longs;ignant po&longs;tea duas cau&longs;as à quibus fluidorum diuer&longs;a, & heteroge­nea natura pendet: prima e&longs;t motuum diuer&longs;itas, &longs;ci­licèt quia pariculæ minimæ aquæ diuer&longs;o modo agi­tantur, ac mouentur particulæ aeris ambientis, & hinc pendere aiunt quod aquæ particulæ nequeant &longs;ua&mtail; vim motiuam exercere intra aerem, & propterea co­gantur motu reflexo excurrere intra profunditatem eiu&longs;dem aqueæ guttulæ, & ex hi&longs;ce motibus reflexis &longs;phæricam figuram guttæ efformari aiunt. Secund&atail; cau&longs;a e&longs;t pororum a&longs;&longs;imetria, inquiunt enim poro&longs;i­tates aeris eius figuræ e&longs;&longs;e, vt particulæ aquæ nequa­quam po&longs;&longs;int per incongruentes poro&longs;itates aeris in­&longs;inuari, & excurrere. Vndè guttula aquæ perindè ab aere coercetur, ac &longs;i e&longs;&longs;et fornix marmoreus.

Defectum analogiæ flui dornm, aut a diuet&longs;it ai&etail; motunm aut ab incongrutia poroium pendere c­&longs;cut.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXVIII.

Ob motuum diuer&longs;itatem aquæ, & aeris non po&longs;&longs;unt aquæ guttulæ &longs;phæricè conglobari.

ET quoad motuum diuer&longs;itatem pertinet, notan­dum e&longs;t verum non e&longs;&longs;e, quòd motus vnius cor­poris omninò impediatur à motu diuer&longs;o alterius, hoc enim contingit quando prædicti motus &longs;unt in­ter &longs;e contrarij per eamdem rectam lineam, & æqua­libus viribus, & velocitatibus facti; &longs;i enim non &longs;int inter &longs;e contrarij, &longs;ed ambo ad ea&longs;dem partes tendant, tunc non omninò impeditur motus alterius corporis, &longs;ed tantummodò alteratur quoad directionem, vel circa velocitatem; quia verò aduer&longs;arij &longs;upponunt motiones partium tum aquæ cùm aeris, vagas, & di­uer&longs;imodas &longs;ursùm, deorsùm, & lateraliter, erit om­ninò impo&longs;&longs;ibile, vt &longs;em per motus particularum aquæ opponantur motionibus, quibus partes aeris agitan-tur, & &longs;i hoc verum e&longs;t, oportet vt ex parte, & aliquan­do impediri po&longs;&longs;it motus partium aquæ ab aere am­biente, &longs;ed frequentiùs, & vt plurimùm nullum im­pedimentum motioni aquæ afferent, & tunc &longs;e mu­tuo penetrabunt, & ideò non vnientur &longs;phæricè gut­tæ aqueæ, quod e&longs;t fal&longs;um.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Præterea &longs;i aer valdè expan&longs;us, & rarior e&longs;t, quàm aqua, & tam infirmæ, & de bilis con&longs;i&longs;tentiæ vt faci­lè à quacumque exigua vi di&longs;&longs;ipari, & è &longs;uo loco di­moueri po&longs;&longs;it, veri&longs;imile e&longs;t vt partes aquæ den&longs;io­res, & con&longs;i&longs;tentes po&longs;&longs;int, dùm mouentur, facilè ae­reas particulas è &longs;uis locis expellere, & &longs;ic per eius &longs;ub&longs;tantiam penetrare; quod profectò ab ip&longs;a expe­rientia confirmari videtur, nam videmus vapores a­queos è mari, & lacubus exhalantes &longs;umma facilita­te per aerem penetrare, cùm con&longs;tet vapores nil aliud e&longs;&longs;e, quàm congeriem exili&longs;&longs;imarum aquæ particula­rum, quæ motu placido, & tranquillo ab aqua difflan­tur, tempore hyemali, ab&longs;que adiumento ignis, aut alterius rapidæ violentiæ. Et profectò numquam aer reperiri pote&longs;t &longs;incerus ab&longs;que admi&longs;tione minima­rum aquæ partium, vt con&longs;tat ex experimentis i&ntail; no&longs;tra Academia experimentali Medicea factis; igi­tur &longs;icuti illæ minimæ aquæ particulæ vaporem com­ponentes à diuer&longs;a aeris agitatione non retardantur, nec impediuntur quin liberè, & impunè aerem pe­netrare po&longs;&longs;int, &longs;ic paritèr particulæ illæ guttæ pen­dulæ terebrare poterunt aeris ambientis con&longs;i&longs;tentiam, & proindè aerearum partium diuer&longs;æ motiones non impedient effluuium, & motionem vagam partium aquæ. Imò &longs;i quis hoc negotium attentè perpendat, percipiet ab ij&longs;dem partibus aqueis potius impediri motiones eius, quàm ab aere externo; primò qui&atail; &longs;unt æquè con&longs;i&longs;tentes, & corpulentæ, & &longs;ic non po&longs;­&longs;unt vici&longs;&longs;im è &longs;uis locis dimoueri, ac expelli: in&longs;upèr cum earum motus &longs;int vagi, & inordinati, non po&longs;sunt omnes ad ea&longs;dem partes dirigi, & ideò vna pars &longs;u­per aliam incidens motu contrario, vici&longs;&longs;im &longs;e &longs;e i&ntail; progre&longs;&longs;u impedient. Ad hæc, vbi dee&longs;t aer, deficiet pror&longs;us cau&longs;a impediens motiones particularum a­quæ, proptereà quòd vbi aer non ade&longs;t, neque eius motus impedimentum afferre poterit agitationi par­tium aquæ. hoc autem contingit in vacuo Torricel­liano, vbi nullo pacto impedirentur motiones earun­dem particularum aquæ, imò faciliùs per &longs;patium fe­rè vacuum &longs;pargi di&longs;&longs;iparique po&longs;&longs;ent, & proindè non cogerentur motu re&longs;lexo intra ea&longs;dem guttas regre­di, agitari, con&longs;tiparique, & ideò ce&longs;&longs;aret cau&longs;a, & nece&longs;&longs;itas ob quam guttulæ aquæ in vacuo, vel in ae­re rari&longs;&longs;imo &longs;ph&ecedil;ricum tumorem acquirere deberent, & tamen hoc repugnat experientiæ, cùm in prædicto vacuo guttulæ non minùs rotundæ, quàm in aere a­perto, tornentur.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXIX.

Incongruentia, & angustia pororum aeris non po&longs;&longs;et impedi­re diffu&longs;ionem particularam aquæ per aerem.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

SI po&longs;tea con&longs;ideremus incongruentiam pororum, patet verum non e&longs;&longs;e aduer&longs;ariorum a&longs;&longs;ertum cum aiunt, ideò ab aere impediri motiones partium aqu&ecedil;, quia orificia pororum aeris &longs;trictiora &longs;unt, quam vt per ea aquæ particulæ ingredi, & fluere po&longs;&longs;int, nam hinc inferre liceret neque aqueas particulas per ipsammet aquam cieri, & excurrere po&longs;&longs;e; facilè enim percipi­tur, quòd in aqua poro&longs;itates non po&longs;&longs;unt e&longs;&longs;e adeò amplæ, vt per eas intromitti po&longs;&longs;int particulæ eiu&longs;­demmet aquæ, &longs;ed debent e&longs;&longs;e multò minores, &longs;icuti inter&longs;titia, quæ in aceruo granorum tritici, vel milij intercipiuntur, &longs;emper minora &longs;unt, quam grana eiu&longs;­dem tritici, vel milij, aliàs facta acerui concu&longs;&longs;ione &longs;e mutuò magis con&longs;tringerent amplexarentur qu&etail; granula prædicta, intromi&longs;&longs;is nempè granulis in ei&longs;­dem amplis inter&longs;titijs. Hinc &longs;equitur vt æquè diffi­cilè aquæ particulæ per ip&longs;am aquam moueri, agita­rique po&longs;&longs;int, quàm per aerem, quia nempè æquè in­commodus e&longs;t progre&longs;&longs;us aquæ per aquam, ac per ae­rem; &longs;i verum e&longs;t requiri poro&longs;itates in fluido tantæ amplitudinis vt capaces &longs;int particularum aquæ ad lioc vt per prædictum fluidum moueri queant. cùm­que aquæ angu&longs;tæ poro&longs;itates non impediant motum particularum aquæ per ip&longs;am aquam. ergò pariter angu&longs;tia pororum aeris non impediet motum partium aquæ per aerem.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXX.

Facilè aquæ particulæ per aerem moueri po&longs;&longs;unt, non quia per eius poro&longs;itates in&longs;inuantur, &longs;ed quia aereas particu­las &longs;olutas, & amouibiles expellere è &longs;uis locis poßunt.

HInc deducitur, quòd vera cau&longs;a, quare aqua fa­cilè per aquam penetrare, & fluere pote&longs;t, non &longs;it amplitudo pororum eius, &longs;ed quia partes ip&longs;ius aquæ facilè expelli po&longs;&longs;unt è &longs;uis locis vt locum ce­dant particulis aqueis, quæ ibidem in&longs;inuari debent, & ni&longs;i anteriores aquæ particulæ è &longs;uis locis expelle­rentur, nequaquàm aliæ partes ibidem &longs;uccedere, & fluere po&longs;&longs;ent. Si igitur hoc verum e&longs;t, percipimus, quòd particulæ aqueæ po&longs;&longs;unt quoque aerem pene­trare, & per eius profunditatem fluere, licèt aer po­rostàm re&longs;trictos, & angu&longs;tos habeat, vt aquæ parti­culæ per eos ingredi nequeant, &longs;ufficit enim vt aereæ particulæ po&longs;&longs;int è &longs;uis loculis expelli, vt ibidem a­queæ partes in&longs;inuari po&longs;&longs;int, eodem modo, ac con­tingit in ip&longs;amet aqua. Quod autem hoc faciliùs i&ntail; aere effici valeat, quàm in aqua, patet ex eo, quòd ae­reæ particulæ magisraræ, & expan&longs;æ, & ideò minus re&longs;i&longs;tentes &longs;unt, quàm partes aqueæ; non erit igitur difficile vt partes aquæ ip&longs;o aere &longs;olidiores è &longs;uis lo­cis expellant particulas aeris, & &longs;ic facilè per eas a­qua moueatur. Adde quòd experientia con&longs;tat aque­as particulas perpetuò intra aerem in&longs;inuari, vt &longs;upra dictum e&longs;t de vaporibus; & reuerà nunquam reperiri pote&longs;t aer omninò aridus, & ab&longs;que vlla admixtione aquæ, &longs;ed e&longs;t veluti &longs;pongia quædam.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXI.

Licèt ob defectum analogiæ motus partium aquæ impedire­tur ab ambiente aere, non proindè &longs;phæricè conglobari po&longs;&longs;et.

TAndèm dato quòd aquæ particulæ ob defectum analogiæ fugerent ab aere ambiente, & impe­direntur tamquam à fornice, & proindè motu refle­ro excurrerent intrà eamdem aquam, non indè&longs;equi­tur quòd &longs;phæricè guttæ ip&longs;æ efformari po&longs;&longs;ent. Fin­ge enim in aliquo lacu innumeros pi&longs;ciculos, vel an­guillulas intra vtrem, vel &longs;accum raræ, & cedentis con­&longs;i&longs;tentiæ contineri, & æquè impediri à pelle, vel &longs;ac­cocedente, & di&longs;trahibili, ac aquæ particulæ ab ip­&longs;o aere, quia videmus pi&longs;ciculos minimè &longs;phæricè conglobari, &longs;ed in prædicta cauitate vtris oblong&atail; expatiari. idip&longs;um contingere deberet in aqueis par­ticulis coercitis à reti aereo, quæ licèt miris modis agitarentur, nihilominùs &longs;phæricam rotunditate&mtail; acquirere non po&longs;&longs;ent; & ratio e&longs;t quia vt plura cor­pora fluida &longs;pontè contornentur oportet vt omnes tendant directè versùs vnum punctum intermedium, & præterea oportet vt vires motiuæ non &longs;int &longs;emper inter &longs;e æquales, &longs;ed maiorem vim impul&longs;iuam ha­beant, quò magis à prædicto centro di&longs;tant. igitur ex his omnibus licèt concludere, quòd neque defe­ctus analogiæ, nec diuer&longs;itas motuum, neque incon­gruentia pororum aeris cau&longs;a e&longs;&longs;e pote&longs;t rotundita­tis guttularum fluidarum.

Prop. 16

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Po&longs;tquam reiecimus aliorum fal&longs;as &longs;ententias, re­&longs;tat modò vt veram cau&longs;am huius effectus pro viribus detegamus. & primò debet præmitti &longs;equens propo­&longs;itio mechanica.

PROP. CLXXII.

Si corpus angulo&longs;um innixum parietis verticalis a&longs;perita­tibus &longs;u&longs;tineatur à potentia termino oppo&longs;ito, & horizon­tali eiu&longs;dem corporis applicata; potentia ad corporis pondus &longs;e habebit, vt di&longs;tantia centri grauitatis eius à fulcimento ad di&longs;tantiam poten­tiæ ab eodem fulcimento.

SIt corpus D à pluribus angulis comprehen&longs;um, & paries verticalis AB, cuius &longs;uperficies &longs;it a­&longs;pera, & denticulata, in huius lo­

co B innitatur &longs;u&longs;tineaturque ex­tremitas angulo&longs;a corporis D, vt nimirum minimè excurrere po&longs;&longs;it deor&longs;um; &longs;u&longs;pendatur po&longs;teà op­po&longs;ita eius extremitas E ab aliqua potentia, tunc vis eleuans in E mi­nor erit pondere corporis D, & ad eius grauitatem ab&longs;olutam eamdem proportionem habebit, quam di&longs;tantia BD à centro grauitatis prædicti &longs;olidi v&longs;que ad parietem habet adlongitudinem EB totius &longs;axi; quia corpus graue D &longs;u&longs;penditur in medio vectis horizontalis EB à dua­bus potentijs, ab illa quam exercet potentia &longs;u&longs;ten­tans E, & ab a&longs;peritate parietis denticulati in B, er­gò ex mechanicis potentia E ad re&longs;i&longs;tentiam ponderis Deandem rationem habet quam di&longs;tantia DB ad to­tam vectis EB longitudinem.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXIII.

Ii&longs;dem po&longs;itis eadem potentia eleuare altiùs poterit conuer­tendo, & rotando corpus polihedrum regulari &longs;imile innixum a&longs;peritatibus eiu&longs;dem verticalis parietis.

SIt corpus D angulo&longs;um, & regulari &longs;imile, ita vt centrum grauitatis eius &longs;it quoque centrum ma­gnitudinis eiu&longs;dem. Dico quòd eadem potentia &longs;ub­dupla E poterit eleuare corpus graue D ad quallibet altitudinem parietis AC; quia cùm &longs;olidum D &longs;it re­gulare, & habeat figuram angulo&longs;am, & denticula­tam, vt in quolibet &longs;itu &longs;uæ &longs;uperficiei po&longs;&longs;it adnecti, & &longs;u&longs;tineri in &longs;ub &longs;equentibus a&longs;peritatibus parietis denticulati CA, &longs;equitur vt quo modolibet reuolua­tur corpus D, &longs;emper in &longs;ub &longs;equentibus eminentijs parietis a&longs;peris AB paritèr &longs;u&longs;tineatur fulciaturque, atque in eodem &longs;itu horizontali ab ij&longs;dem duabus potentijs corpus D &longs;u&longs;tinebitur, &longs;cilicèt à potenti&atail; E, & ab aliqua denticulari eminentia parietis AC; cùmque &longs;emper eadem proportio remaneat inter eo­rum di&longs;tantias à contactu, &longs;cilicèt inter DB ad BE, igitur &longs;emper eadem vis E &longs;u&longs;tinere, & impeller&etail; &longs;ursùm poterit eamdem re&longs;i&longs;tentiam corporis D; qua­propter fiet continua vertigo &longs;olidi D nedùm circ&atail; eius centrum, &longs;ed etiam rotando, adh&ecedil;rendoque lon­gitudini verticali BA, & proindè eleuabitur ad quan­cum que &longs;ublimitatem A.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXIV.

Particulæ aquæ &longs;uperficiales po&longs;&longs;unt rotando altiùs eleuari parieti va&longs;is adhærendo à vi ponderis aqua collate­ralis impul&longs;æ.

PO&longs;tea con&longs;idero in va&longs;e XRSV in aquæ &longs;uprem&atail; parte laminam horizontalem conflatam ex mi­nimis aquæ particulis A, B, D, tunc

exiguum corpus A parietem &longs;ir­mum contingat in L, ob huius a­&longs;peritatem fulcietur, &longs;u&longs;tentabi­tur que terminus L granuli aquei A, reliqua verò portio eius ver­sùs C cùm non adhæreat nequ&etail; &longs;u&longs;tentetur ab vllo pariete, fulcietur, &longs;u&longs;tinebiturque à &longs;ubiecta aqua FI, quæ non grauatur ab integro pon­dere totius aquei granuli A, &longs;ed ab eius medietat&etail;, propterea quòd concurrit ad id &longs;u&longs;tentandum parie­tis &longs;cabrities L. Con&longs;ideretur po&longs;tea con&longs;equens mi­nimum granulum aqueum B, quod à pariete remotum integram &longs;uam grauitatem exercet comprimendo &longs;ub­iectam a quam IE, & quia partium aquæ EIF, æquali­tèr &longs;cilicèt horizontalitèr iacentium, IE magis pre­mitur quàm FI, cùm illa duplum pondus, &longs;cilicèt in­tegrum ip&longs;ius B &longs;u&longs;tineat, hæc verò &longs;emi&longs;&longs;em ponde­ris ip&longs;ius A, ergo pars FI minus pre&longs;&longs;a &longs;ursùm impel­letur ab EI magis pre&longs;&longs;a, proindeque pars aquæ FI vim faciet &longs;ursùm impellendo terminum C granuli aquei A; quia verò eius extremitas L foueolis a&longs;pe­ris parietis adhæret, impeditur retineturque nè dire­cto motu &longs;ursùm ferriqueat, ergò nece&longs;sè e&longs;t, vt gra­nulum A flectatur ad modum vectis circa firmum ter­minum L, cùmque tactus, & adhæ&longs;io in pariete reno­uetur continentèr po&longs;t flexionem &longs;ursùm termini C non &longs;ecùs, ac in rotis dentatis contingit, pariterque re­nouetur &longs;emper cau&longs;a vlterioris &longs;u&longs;pen&longs;ionis granuli A, quæ e&longs;t minor compre&longs;&longs;io &longs;ubiectæ aquæ FI quam EI; igitur &longs;em per renouatur flexio vectis CL &longs;ursù&mtail; proindeque minuti&longs;&longs;imum granulum aquæ A motu vertigino&longs;o, & reptitio a&longs;peritatibus parietis LK adhærendo eo v&longs;que eleuabitur, quou&longs;que fiat æqui­librium cum aqua collaterali.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

CerollPr. 10.

Videndum modò qua ratione po&longs;&longs;int &longs;aluari effe­ctus omnes, qui in guttis exiguis ob&longs;eruantur.

PROP. CLXXV.

Ratio affertur quare guttæ aquæ pendulæ è &longs;uperficie prona &longs;olidi corporis &longs;ustineantur.

Cap. 8. cur exiguæ aqu¸ guttæ &longs;upra libellam aquæ a&longs;cendunt.

ET primò con&longs;ideretur gutta pendula ex &longs;uperfi­cie prona rami alicuius arboris, cuius figur&atail; videtur conoidalis parabolica: reddi debet hìc cau&longs;a efficiens, & formalis huius &longs;u&longs;pen&longs;ionis; concipian­tur externæ &longs;uperficiales particulæ huiu&longs;modi gutt&ecedil;, quæ vici&longs;&longs;im connexæ à &longs;uis machinulis aliquo pacto incuruatis ad modum arcus efficiant veluti linteum, vel &longs;accum in eius perimetro annexum &longs;ummitati li­gni duri, & con&longs;i&longs;tentis; partes verò intermediæ gut­tulæ &longs;ua grauitate naturali premunt, & di&longs;trahunt lin­teum, vel rete &longs;uperficiale, at quia energia machi­nularum non cedit vi pu&longs;illæ grauitatis guttulæ pen­dentis, fit vt æquatis momentistota gutta &longs;u&longs;pen&longs;&atail; hæreat.

PROP. CLXXVI.

Quare globuli fluidi pendentes è filo paritèr fluido &longs;u&longs;tineantur.

SEcundo loco &longs;it pila fluida pendula ex filo pari­tèr fluido, vt euidentiùs contingit in Saliua, & in alijs humoribus glutino&longs;is; hìc iam concipi debent hinc inde à filo in orbem particulæ fluidi, quæ excur­rendo deorsùm vt graues ad infimum fili &longs;itum, ibi con­glutinatis, concatenati&longs;que externis particulis ope machinularum earum efformant veluti &longs;acculum reti­cularem intra quem tanta moles fluidi contineri pote&longs;t, vt eius pondus non &longs;uperet robur machinularu&mtail; glutinis.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXVII.

Et cur globulus fluidus pauimento innixus; &longs;u&longs;tineatur.

TErtiò pila fluida innixa pauimento paritèr &longs;u&longs;ti­netur veluti à filo, &longs;eù virga perpendiculari ad planum &longs;ubiectum à quo &longs;u&longs;tentatur; à prædicta vir­ga in orbem colligantur aliæ particulæ eiu&longs;dem flui­di, quæ in èxigua ba&longs;i fulciuntur à plano &longs;ubiecto, quando ob ariditatem eius, & incongruitatem po­rorum aqua non diffluit, nec ip&longs;um humectat; in tali ca&longs;u filum fluidum perpendiculare perinde agit, ac filum pendulum; &longs;ed guttæ figura differt aliquo pa­cto à præcedenti, non enim e&longs;t &longs;phærica, nec oblon­ga oualis, &longs;ed inferiùs dilatatur, & &longs;upernè acumen veluti conoidale acquirit.

PROP. CLXXVIII.

Declaratur quomodò, & quou&longs;que ex nouo affluxu guttulæ augentur, & quare po&longs;t violentam fluidi tractionem denuò &longs;ponte &longs;ua recolliguntur.

IN primo, & &longs;ecundo ca&longs;u ex affluxu noui fluidi augeri pote&longs;t moles guttæ pendulæ, vt eius pon­dus maius &longs;it, quàm vt à vi glutinis &longs;u&longs;tineri queat, & tunc elongatur infernè, & tandem di&longs;rumpitur, & decidit, at pars re&longs;idua oblonga recolligitur &longs;ursùm, efficitque nouam exiguam globo&longs;itatem; cau&longs;a verò huius recollectionis, & a&longs;cen&longs;us &longs;ursùm hæc e&longs;t, quia à pondere, & à motu ingentis guttulæ decidentis ma­chinulæ re&longs;iduarum partium fluidi violentèr di&longs;tra­ctæ &longs;pontè &longs;ua apt&ecedil; natæ &longs;unt, denuò &longs;e &longs;e recollige­re, reducique ad naturalem &longs;itum, &longs;icut contingit in arcu, & in qualibet machina, quæ po&longs;t violenta&mtail; di&longs;tractionem, exten&longs;ionemque, denuò &longs;e flectit re­duciturque ad pri&longs;tinum &longs;itum, cùmque in hac vni­uer&longs;ali actione machinularum filum fluidum compo­nentium &longs;ub&longs;equatur motus regre&longs;&longs;us &longs;ursùm, nec motus fieri po&longs;&longs;it ab&longs;que impetu, igitur ab hoc præ­dictæ fluidi particulæ impelluntur altiùs quàm exi­gat naturalis earum grauitas, & hinc &longs;equitur vt de­nuò po&longs;tea affluentibus circumcirca fluidi particulis, denuò gutta rotunda efformetur.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

In tertio ca&longs;u Propo&longs;it. præcedentis augeri pote&longs;t gutta duplici modo, & ex concur&longs;u noui fluidi &longs;u­pernè &longs;en&longs;im additi, quou&longs;que vis glutinis &longs;ufficiat, vt pondus guttæ &longs;u&longs;tinere valeat, nè decidat, &longs;ed dum augetur, lateralitèr cre&longs;cit, ampliaturque, & &longs;ic gut­ta amittit pri&longs;tinam globo&longs;itatem.

PROP. CLXXIX.

Quare duæ guttæ homogeneæ &longs;e &longs;e tangentes colliguntur vniunturque.

SEd dignior inqui&longs;itione e&longs;t recollectio duarum guttularum quoties lateralitèr &longs;e mutuò tangant, ex quibus componitur vnica gutta rotunda. Ratio e&longs;t, quia partes eiu&longs;dem fluidi homogenei facillimè excurrunt &longs;upra, & intra &longs;e ip&longs;as, dum propter &longs;oli ariditatem, quando ip&longs;um humectare, & madeface­re non po&longs;&longs;unt ob pororum incongruentiam, oportet vt omnes &longs;imul in&longs;i&longs;tant &longs;uper &longs;ilum fluidum, vel &longs;uper axim perpendicularitèr plano &longs;ubiecto in&longs;i&longs;tentem, & &longs;ic in orbem, vt priùs dictum e&longs;t, axi connectuntur, & globum integrum efformant magis tamen contu­&longs;um, & depre&longs;&longs;um, quàm antea.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Sed dices, quænam e&longs;t vis motiua, quæ impellit partes duarum guttularum &longs;e tangentium vt &longs;ursùm a&longs;cendant in &longs;ummitate guttulæ amplioris ex eis con­po&longs;itæ? Re&longs;pondeo, quòd hoc pendet ex vi compre&longs;­&longs;iua collateralium partium, quæ cùm non po&longs;&longs;int pla­no &longs;ubiecto vniri, & à vi glutinis &longs;uperatur pondus partium eiu&longs;dem fluidi, &longs;equitur vt ratione vectis particulæ intermediæ eleuentur. Vniuer&longs;a hæc ope­ratio &longs;ic perficitur: pri­

mò duo globi mercurij A BCD, & EBFG innixi pauimento VX in locis C, & F &longs;e tangant latera­liter in B. hinc patet, quòd partes fluid&ecedil; BC, & BF facilè intra &longs;e ip&longs;as excurrendo &longs;e mutuò ample­cti po&longs;&longs;unt, & excludere aerem intermedium BCF ini­tio facto à contactu B versùs C, & F. Idip&longs;um accidit in&longs;upremis partibus AB, & EB, vnde efformabitur figura qua&longs;i &longs;phæroidalis, & oualis HIKL, qu&ecedil; po&longs;tea magis rotunda reddetur, &longs;ed aliquo pacto contu&longs;a, & compre&longs;&longs;a remanebit, propterea quòd circa axi&mtail; HK ad planum &longs;ubiectum
VX perpendicularem al­ligantur in orbem partes in&ecedil;qualium momentorum, quia nempè inæqualitèr, &longs;cilicèt magis diftant ab axi HK partes laterales I, & L quàm anterior, & po&longs;terior, & ideò iuxtà le­ges mechanices partes minùs pre&longs;sæ à magis com­pre&longs;&longs;is expelli debent longiùs ab axi.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Præterea ex dictis, ratione vectis partes fluidi I, & L remotiores ab axe HK &longs;ursùm impellent eas, quæ eidemaxi proximæ&longs;unt, ac proindè eleuabitur flui­da eminentia OMN, & con&longs;equentèr latera I, & L con&longs;tringentur vt in P, & R.

Prop. 173.

PROP. CLXXX.

Quare filum ceræ alaccæ, vitri, aui metalli liquefacti à flamma candelæ in&longs;ufflatæ ope fistulæ dum lique&longs;cit recolligitur pilam rotundam efformans, & augons.

RAtio huius effectus e&longs;t quia dum à copio&longs;o, & vehementi igne particulæ vitri di&longs;gregantur, non tamen omninò, neque &longs;ecundùm totum, nam vni­cam ma&longs;&longs;am inflatam, & fluidam componunt, & ideò ex parte &longs;e &longs;e tangunt, ergo cùm habeant glute&ntail;, &longs;cilicèt habeant machinas flexiles, & re&longs;ilientes, &longs;it vt à prædicta ignis penetratione violentèr di&longs;trahan­tur machinulæ illæ, vt totidem arcus, & ideò pro eo­rum ingenio vim habent &longs;e recolligendi, & &longs;e vnien­di cum reliquis partibus fili liquefacti, à quibus di­&longs;tractæ fuerant: cùmque adueniant duæ aliæ cau&longs;æ accidentales, quarum vna e&longs;t durities, aut minor flu­xibilitas perimetri, aut &longs;uperficiei eius externæ re­&longs;pectu partium intermediarum magis fluidarum, vn­de efficitur veluti epidermis, & &longs;acculus con&longs;i&longs;ten­tior; altera cau&longs;a e&longs;t inflatio, quam efficit ignis ve­hementi&longs;&longs;imè agitans internas vitri partes fluidiores, quæ cùm circumdentur ambianturque à perimetro, & &longs;uperficie duriori, & tenaciori, veluti à &longs;acculo, &longs;it vt à vi glutinis dum conantur &longs;e recolligere par­tes prædicti fluidi tota ma&longs;&longs;a fu&longs;a, & in&longs;lata retraha­tur, recolligaturque versùs filum, & &longs;ic efformetur globulus, & eadem ratione augeatur eius diameter, at dum augetur pila cre&longs;cente pondere amittit prio­rem illam formam orbicularem, & efficitur gutta ob­longa deorsùm tendens. modò quia vis glutinis, &longs;eù energia machinularum e&longs;t cau&longs;a retractionis particu­larum fu&longs;arum, hoc dum &longs;uperat vim exigui ponde­ris prædictæ guttulæ facilè poterit ip&longs;am mouere, & retrahere &longs;iuè &longs;ursùm, &longs;iuè lateralitèr.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXXI.

Declaratur quemadmodum lamina gracilis aqua grauior &longs;pecie foueam efficit in aqua dum innatat, & quare monticuli illi aquei non decidant.

PRo clariori eiu&longs;dem problematis intelligenti&atail; inquirenda e&longs;t ratio alterius effectus, qui in flui­dis ob&longs;eruatur: in va&longs;e BCEI

aqua pleno applicetur graci­li&longs;&longs;ima lamina ænea FG ho­rizontalitèr, hæc quidem &longs;i arida fuerit licèt grauior &longs;pe cie &longs;it ip&longs;a aqua, non omninò demergetur, nec ad fundum va&longs;is feretur, &longs;ed de&longs;cen­det infra &longs;upremam libellam aquæ IB, ibique inna­tabit efficiendo argines aqueos tumidos, & eleuatos GAB, & IF, qui non &longs;ecus, ac &longs;i e&longs;&longs;ent parietes im­pediunt effluxum &longs;upremæ aquæ AB vt nequeat de­&longs;cendere in profunda fouea IFGA genita à depre&longs;&longs;io­ne eiu&longs;dem laminæ: & hìc anima duertendum e&longs;t ca­uitatem, &longs;eu puteum IFGA effici tunc &longs;olummodò, quando excurrit ad prædictum &longs;patium replendu&mtail; aliquod fluidum leuius, &longs;ed non homogeneum ip&longs;i aquæ veluti e&longs;t aer, vel vacuum Torricellianum: at adueniente aqua, vel fluido aquæ naturam participan­te, vt e&longs;t vinum, tunc margines aquei GAB, & IF non per&longs;i&longs;tent, &longs;ed di&longs;rumpentur, & deorsùm dilap&longs;i fo­ueam replebunt. Præterea notandum e&longs;t fieri no&ntail; po&longs;&longs;e vt argines prædicti aquei cuiu&longs;cumque altitu­dinis per&longs;i&longs;tant, &longs;i enim quartam partem latitudinis digiti auricularis &longs;uperauerint, &longs;ubitò deorsùm præ­cipitantur. Ratio quæ a&longs;&longs;ignari &longs;olet, huius effectus, aut e&longs;t compre&longs;&longs;io aeris multoties à nobisreiecta, aut quia veluti in aceruo granorum tritici, vel arenæ con­tingit efficitur montuo&longs;itas quædam decliuis, qui&atail; nimirùm &longs;upremæ partes fulciuntur ab inferioribus, vt arginem inclinatum efforment, qui non pote&longs;t e­leuari vltra angulum &longs;emirectum, aliàs &longs;ubitò grana ip&longs;a deciderent deorsùm; concipiunt ergo minim&atail; aquam componentia e&longs;&longs;e minuti&longs;&longs;ima quædam gra­nula, & proindè ad in&longs;tar arenæ efformare po&longs;&longs;e ar­ginem prædictum. Sed hoc non videtur &longs;ufficiens duplici de cau&longs;a, primò quia argines aquei non ele­uantur ad quamlibet altitudinem, vt contingit in a­ceruo granorum tritici, licèt enim angulus inclina­tionis arginis aquei, &longs;cilicèt complementum anguli AGF, minor &longs;it &longs;emi&longs;&longs;e vnius anguli recti, non pote&longs;t altitudo prædicti arginis eleuari vltra altitudine&mtail; quadrantis latitudinis digiti auricularis, cùm oppo­&longs;itum ob&longs;eruetur in aceruo granorum tritici. Præte­rea argines aquei BAG, & FI &longs;unt curui, & gibbi, & in infima eius parte G angulus inclinationis maior e&longs;­&longs;e &longs;olet &longs;emirecto, igitur requiritur aliqua alia cau&longs;a præter fulcimentum particularum minimarum, quod in arena, & in aceruo granorum tritici contingit. Hoc egregiè ex no&longs;tra hypothe&longs;i &longs;aluatur, dum enim la­mina FG de&longs;cendit infra &longs;upremam aquæ libellam IB, particulæ extimæ &longs;uperficiei aquæ CAG, & IF quæ mutuò inter &longs;e connectebantur, ob iam dictam lanu­ginem flexibilem, & re&longs;ilien­
entem, po&longs;tea di&longs;trahun­tur machinul&ecedil;, & ideò fortiùs ad inuicem vinciuntur, & pro­indè efformant veluti pleu­ram, &longs;eù reticulum à quo re­tineri, & impediri po&longs;&longs;unt partes aquæ prædicti mon­ticuli GAB, &longs;ed non licet prædictam montuo&longs;itatem ad quancunque altitudinem eleuare, propterea quòd re&longs;i&longs;tentia machinularum ip&longs;ius aquæ exigui roboris e&longs;t, & proindè tamdiù per&longs;euerabit, quamdiù pu&longs;il­lam vim grauitatis &longs;uperat, quæ naturali in&longs;tinctu deorsùm tendere debet obliquo, & inclinato itine­re, & ideò eius momentum men&longs;uratur à perpendi­culari altitudine &longs;upra planum FG, quæ valdè exi­gua e&longs;t vt diximus.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXXII.

Vis impellens, & retinens argines aqueos eleuatos &longs;upra aquæ libellam non e&longs;t propria ip&longs;ius aquæ, neque aeris, &longs;ed e&longs;t grauitas eiu&longs;dem aquæ collateralis legi­bus mechanicis operando.

DEbemus modò rationem afferre alterius phœ­nomeni difficilioris. &longs;it vas aqua plenum RDEI in quo immergatur quodlibet corpus &longs;olidum, & du­rum FGK, quod &longs;it aridum, & non vngatur &longs;ebo, vel alia &longs;imili vnctuo&longs;a materia, huius verò corporis re­maneat vna pars FK eminens &longs;upra aquæ libella&mtail;, vel emineat paries eiu&longs;de&mtail;

va&longs;is, tunc con&longs;tat experientia, quòd aqua non per&longs;i&longs;tit in in­fima eius libella horizontali AK, &longs;ed repit, a&longs;cenditque per &longs;uperficiem eleuatam KG efformando pri&longs;ma aqueum triangulare, cuius &longs;ectio e&longs;t BGK, ibidemque retinetur &longs;u&longs;penditurque mons prædictus aqucus, non &longs;ecus ac &longs;i à pariete cur­uo BG impediretur eius fluxus deor&longs;um ver&longs;us aquam &longs;ubiectam AB. Quia verò aqua non amittit naturalem eius grauitatem, a&longs;&longs;ignari debet cau&longs;a à qua &longs;u&longs;pen&longs;a retinetur, & quæ vis ip&longs;am &longs;ursùm prius impulit. Hæc profectò aut propria, & naturalis e&longs;t ip&longs;ius aqu&ecedil;, vt nimirùm &longs;ponte &longs;ua &longs;ursùm a&longs;cendat, ibidemqu&etail; retineatur, aut hoc &longs;it ab aliqua cau&longs;a violenta ex­terna. Quòd verò non &longs;it vis propria, & natiua ip&longs;ius aquæ, patet ex &longs;uperiùs dictis, quia nimirùm &longs;emper aqua grauis e&longs;t, exercetque &longs;uam vim compre&longs;&longs;iuam versùs centrum telluris, vt &longs;en&longs;us euidentia con&longs;tat.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Alij po&longs;tea recurrunt ad aeris vim compre&longs;&longs;iuam, aiunt enim aerem contiguum interno va&longs;is parieti GK minori energia &longs;ubiectam aquam K comprimere, quam aer HB à pariete remotus premat &longs;ubiectam aquam B, propterea quòd illa quodammodo ab a&longs;perita­tibus parietis retinetur, ac impeditur ne libero co­natu, & fluxu premere queat aquam &longs;ubiectam K cum hæc vniuer&longs;am &longs;uam grauitatis, & virtutis ela&longs;ticæ energiam liberè exercere po&longs;&longs;it; hoc autem fal&longs;u&mtail; e&longs;&longs;e &longs;ic o&longs;tendemus; ablata aquarepleatur vas hydrar­gyro, quia ex hypothe&longs;i aduer­

&longs;arij, aer FKG parieti va&longs;is con­tiguus minori vi comprimit &longs;ub­iectum mercurium K, quàm aer HB ab eodem pariete magis remo tus premat &longs;ubiectum mercurium B, & præterea mercu­rius K, vel &ecedil;quilibratur cum mercurio B, vel minori mo­mento premit &longs;ubiectum fluidum quam idipsum B, eò quòd il­le à parietis a&longs;peritatibus impeditur, hic verò libe­rè premit. igitur hìc quoque eleuari deberet mons mer­curialis versùs parietem, vt in aqua contingit, quod e&longs;t fal&longs;um, & repugnat experientiæ, potiùs enim de­primitur in foueam BGK, non ergo ab illa inæquali aeris pre&longs;&longs;ione aqueus monticulus versùs pariete&mtail; va&longs;is eleuatur. Et licèt re&longs;ponderi po&longs;&longs;et quòd cau&longs;a huius diuer&longs;æ operationis pendeat à defectu analo­giæ mercurij, & parietis va&longs;is, ob quem ille refugit huius contactum, non tamen in dubium reuocatur ab aduer&longs;arijs inæqualis illa aeris pre&longs;&longs;io &longs;upra mercu­rium, quare in rali ca&longs;u operatur vis illa, qua mercu­rius a va&longs;is &longs;uperficie interna &longs;eparatur vnà cum inæ­quali vicompre&longs;&longs;iua aeris, ideò in duobus va&longs;is cy­lindricis angu&longs;tis RST, & VXZ &longs;it amplitudo, &longs;eu ba&longs;is ST maior, quàm XZ in ei&longs;que hydrargyrum in­fundatur v&longs;que ad B, & E.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

Et quianon pote&longs;t mercurij &longs;uprema portio à &longs;uper­ficie interna fi&longs;tulæ &longs;eparari, ni&longs;i &longs;u&longs;pendatur efficien-do tumidum monticulum. Verùm minus grauis mercu­rij moles in &longs;trictiori fi&longs;tula contenti faciliùs &longs;u&longs;pen­ditur, quàm grauior moles eiu&longs;dem latiorem fi&longs;tulam occupans; ergo faciliùs mercurius ab interna &longs;trictio­ris fi&longs;tulæ &longs;uperficie &longs;eparatur, quam ab interna latio­ris fi&longs;tulæ &longs;uperficie, & proinde altius, vel &longs;altem non minùs altè &longs;eparari deberet mercurij monticulus GF quàm CA. po&longs;tea aer perimetris in­

ternis vtriu&longs;que fi&longs;tulæ adhærens æ­què impeditur, & propterea æquè aeris pre&longs;&longs;iones debilitat&ecedil; viribus æ­qualibus &longs;ubiectum mercurium con­primere debent; at intermediæ par­tes aeris versùs axes cylindrorum exi&longs;tentes inæqua­les vires compre&longs;&longs;iuas habebunt, eò quòd inæquali­tèr à &longs;uperficiebus internis va&longs;orum recedunt, quare aer incumbens mercurio in A maiori vi eum compri­met, ac contundet, quàm aer incumbens mercurio in G, igitur validiori vi retundetur monticulus tumi­dus BAD quàm EGL, & ideo altior erit monticulus mercurij EGL, quàm BAD; &longs;ed hoc e&longs;t fal&longs;um, multò enim maior e&longs;t altitudo CA quàm FG, ergo aeris vis compre&longs;&longs;iua nullam inæqualitatem &longs;ortitur, vel non talis e&longs;t vt tàm in&longs;ignes varietates producere valeat, &longs;cilicèt non eleuarentur argines illi aquei &ecedil;què ab ae­re compre&longs;&longs;i, ac reliqua aquæ &longs;uperficies horiz onta­lis. Præterea in vacuo Torricelliano aer ibi non exi­&longs;tens non po&longs;&longs;et eleuare argines aqueos parietibus fi­&longs;tulæ adh&ecedil;rentes; vel &longs;i ibidem remanet minima aeris portio valdè expan&longs;a, & rara erit, & ideò (ex Prop. 105.) eius pondus, & vis compre&longs;&longs;iua minor erit nen­ cente&longs;ima, & octuage&longs;ima pars ponderis aeris ex­terni eiu&longs;dem molis: igitur illa non poterit &longs;upra a­quæ libellam eleuare idem pondus arginis aquei quod in aere aperto ab huius ingenti pondere &longs;u&longs;pendeba­tur: cùmque hoc &longs;it fal&longs;um, æquè enim argines aquei in prædicto vacuo &longs;ublimantur, ac in aere aperto, igi­tur non ab aere ibidem non exi&longs;tente, vel rari&longs;&longs;imo argines prædicti &longs;u&longs;penduntur.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Alij po&longs;tea recurrunt ad &longs;cabritiem, & a&longs;peritatem parietis à qua impeditur de&longs;cen&longs;us, &longs;u&longs;pendunturque particulæ aqueæ; &longs;ed hoc minimè &longs;ufficere videtur, nam ad &longs;ummum dicta &longs;cabrities commoda e&longs;&longs;et, & apta ad retinendam aquam po&longs;tquam &longs;emèl eleuata fui&longs;&longs;et ad illam altitudinem, quatenùs ab a&longs;peritati­bus, veluti vncinis impediretur defluxus aquæ deor­sùm, at non po&longs;&longs;ent aquam &longs;ubleuare, cùm &longs;cabrities vim motiuam non habeat; & &longs;anè a&longs;peritates nedum non adiuuarent, &longs;ed potiùs impedirent aquæ eleua­tionem in prædictis arginibus duplici nomine, primò quia eædem parietis &longs;cabro&longs;itates, quæ vim habent prohibendi defcen&longs;um aquæ, impediunt quoque eius a&longs;cen&longs;um; præterea multò magis, & maiori vi a&longs;cen­&longs;us aquæ impediri deberet quàm eius de&longs;cen&longs;us, quia in a&longs;cen&longs;u aqua præter re&longs;i&longs;tentiam a&longs;peritatis parie­tis &longs;uperare debet impedimentum, & reluctantiam propriæ grauitatis, cum è contra in de&longs;cen&longs;u ab hac adiuuetur. igitur &longs;cabrities parietis non pote&longs;t e&longs;&longs;&etail; cau&longs;a eleuationis aquæ in prædictis arginibus.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Debet modo a&longs;&longs;ignari virtus motiua, quæ eleuat, & &longs;u&longs;tinet aquam &longs;upra propriam libellam v&longs;que ad &longs;ummitatem arginis, & hanc demon&longs;trabo e&longs;&longs;e &longs;im­plicem aquæ grauitatem. Quia aquæ particulæ ad­hærentes parieti va&longs;is in&longs;inuant ramos &longs;uarum machi­nularum intra poro&longs;itates, & foueolas parietis, à cu­ius eminentijs, & a&longs;peritatibus fulciuntur extremi­tates particularum aquæ, quarum oppo&longs;iti termini &longs;u&longs;tinentur, à &longs;ubiecta collaterali aqua, proptereà efficientur veluti totidem vectes conuertibiles circa eorum fulcimenta parieti annexa. Hinc fit vt prædi­ctæ aquæ particulæ exiguam vim compre&longs;&longs;iuam exer­ceant, & minori momento &longs;ubiectam aquam com­primant, cùm partes aquæ collateralis liberè premen­do &longs;upra aquam &longs;ubiectam integram &longs;uam vim, & momentum exerceant, igitur ex prop. 174. partes minùs pre&longs;&longs;æ &longs;ursùm impelli debent à partibus ma­gis compre&longs;&longs;is: & licèt illæ retineantur, & impedian­tur ne motu &longs;ibi ip&longs;i æquidi&longs;tanti ferri &longs;ursùm queant, tamen eadem impedimenta a&longs;peritatum parietis præ­clarè adiuuant flexionem, & turbinationem earun­dem aquæ particularum, igitur à vi motiua grauita­tis maioris aquæ collateralis &longs;lecti, rotari, & impelli &longs;ursùm po&longs;&longs;unt parieti adh&ecedil;rendo eædem aquæ par­ticulæ; dum verò efficitur prædicta eleuatio, &longs;ummi­tates guttularum reuolutarum eminentiores reddun­tur quàm aliæ particulæ parieti adhærentes, igitur tunc prædictæ particulæ iam eleuatæ naturali in&longs;tin-ctu excurrent versùs parietem, cui &longs;uis villis adhæ­rebunt, ex qua adhæ&longs;ione momentum eius grauitatis denuò imminuetur, & ideò renouabitur cau&longs;a vlte­rioris eius eleuationis à compre&longs;&longs;ione laterali aquæ &longs;uo momento non imminuto comprimentis, & hinc &longs;equitur continuatio prædicti a&longs;cen&longs;us rotando, & adhærendo parieti, quou&longs;que efficiatur æquilibrium cum prædicta aqua collaterali liberè premente.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

Et hìc notandum e&longs;t, quòd vis prædictæ adhæ&longs;io­nis aquæ non e&longs;t æqualis in omnibus partibus prædi­ctæ montuo&longs;itatis, &longs;ed omnium maxima e&longs;t illa, quæ retinet mini nas aquæ particulas immediatè parietem tangentes, quæ non &longs;ecùs, ac &longs;i e&longs;&longs;ent claui, vel vn­cini tenaci nexu ibidem in&longs;inuantur, & minima erit vis illa, quæ retinet remoti&longs;&longs;imas, & po&longs;tremas par­ticulas dictæ montuo&longs;itatis aquæ, aliarum verò par­tium illæ, quæ parieti viciniores &longs;unt, maiori tena­citate &longs;u&longs;pendentur, quam aliæ partes aquæ a præ­dicto pariete magis remotæ. Et hinc oritur decliuitas illa montis aquæ pendentis.

Decliuitaprædicti a­quei montis pendet ex in æqualitate virtutis mo­tiuæ.

Hic iam re&longs;oluere po&longs;&longs;umus aliud problema val­dè agitatum, vnde nimirùm proueniat, quòd aqu&atail; in fi&longs;tulis tenui&longs;&longs;imis vtrinque apertis &longs;ursùm a&longs;cen­dat. Et primo loco phænomena, quæ in hac opera­tione ob&longs;eruantur, recen&longs;eri debent.

Proponutur ob&longs;erua­tiones a&longs;cen­&longs;us aquæ in ful gra­cili&longs;&longs;imis.

Po&longs;tquam gracili&longs;&longs;ima fi&longs;tula EH contingit aquæ &longs;uperficiem RV in H videmus, quòd &longs;ubito aqua &longs;en­&longs;im a&longs;cendere incipit ad notabilem altitudinem HK eiu&longs;dem cauitatis &longs;upra aquæ &longs;ubiectæ libellam RV. Siverò prædicta cauitas priùs humectata, & made­facta fuerit, & denuò exinanita &longs;ubitò po&longs;t contactum multò altiùs, & celeriùs v&longs;que ad G aqua perpendi­cularitèr eleuatur, ac a&longs;cendebat

in priori ca&longs;u quando interna fi­&longs;tulæ cauitas arida erat. Præterea &longs;i po&longs;t aquæ exuctionem transfe­ratur fi&longs;tula AB ab aqua ad aerem, non &longs;ecùs in ea perpendiculari­ter erecta fixè retinetur eade&mtail; aquæ moles in eodem &longs;itu, & al­titudine CD, quàm priùs habe­bat. In&longs;uper &longs;i eadem exigua fi­&longs;tula interiùs madida, &longs;ed exina­nita contingat paruulam guttulam aquæ F in palm&atail; manus eleuatam, &longs;i immediatè po&longs;t guttæ contactum fi&longs;tula citò eleuetur, tunc videmus aquam exucta&mtail; non quie&longs;cere in infimo fi&longs;tulæ &longs;itu B, &longs;ed vlteriùs pauli&longs;per &longs;ursùm promoueri, excurrereque &longs;ucce­dente aere in eius infima parte.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXXIII.

Aqua in fi&longs;tulis non a&longs;cendit &longs;pontè &longs;ua à vi motiua particu­larum eius impul&longs;a, neque in&longs;inuatur, retineturque ibidem ab æquilibrio aeris, aut ab internis ca­naliculi a&longs;peritatibus.

RElatis ob&longs;eruationibus inquirendum e&longs;t, an præ­dicta phænomena &longs;aluari po&longs;&longs;int ex no&longs;tris, vel ex aliorum Authorum principijs. Et primò &longs;i aqu&atail; &longs;ponte &longs;ua a&longs;cenditintra fi&longs;tulæ cauitatem à vi parti­cularum eius &longs;e mouentium, igitur aut grauitate om­ninò carent, aut in tali ca&longs;u eam non exercent (quod vltrò aliqui Authores concedunt) &longs;i inquam hoc ve­rum e&longs;t, impo&longs;&longs;ibile e&longs;&longs;et vt aqua in fi&longs;tula immi&longs;&longs;&atail; perpendiculariter erecta exerceret vllam vim com­pre&longs;&longs;iuam deorsùm, & ideò &longs;i fi&longs;tula infernè prolon­garetur, nullo pacto aqua ibidem deorsùm de&longs;cende­ret, quod tamen experientiæ refragatur, nam eadem fi&longs;tula cum aqua contenta in aere translata, & per­pendiculariter ad horizontem erecta &longs;i inuer&longs;o &longs;itu di&longs;ponatur vt pars eius &longs;upina A fiat prona, aut ei alia fi&longs;tula infernè adnectatur, aqua in ea contenta celeri motu de&longs;cendit, &longs;i madida fuerit, quou&longs;que prope infimum orificium perducatur; igitur fal&longs;um e&longs;t a­quæ in fi&longs;tula contentæ particulas grauitate priuari, proindeque &longs;ponte &longs;ua intra fi&longs;tulam a&longs;cendere. Cum verò aiunt cau&longs;am prædicti a&longs;cen&longs;us aquæ pender&etail; ex eo quòd eius particulæ naturali in&longs;tinctu feruntur versùs fluidum aqueum, vel aquæ analogum conten­tum in vitri internis poro&longs;itatibus, nec à grauitate, quam negant, impediri po&longs;&longs;unt: &longs;i hoc, inquam, ve­rum e&longs;&longs;et, madefacta vniuer&longs;a fi&longs;tulæ interna cauita­te, & po&longs;tea exinanita, atque immer&longs;o orificio infra aquæ &longs;ubiectæ libellam eleuari &longs;emper altiùs deberet aqua v&longs;que ad fi&longs;tulæ &longs;upremum orificium, quod ta­men e&longs;t fal&longs;um, non ergo &longs;ponte &longs;ua aqua intra fi&longs;tu­lam eleuatur.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Alijj po&longs;tea aiunt quòd dum fi&longs;tula AB tangit aquam va&longs;is RSV, vel guttulam &longs;u&longs;pen&longs;am F, tunc aer ambiens &longs;uo pondere, & vi ela&longs;tica com­

primit infernè partem aqu&ecedil; F ex­tra fi&longs;tulam exi&longs;tentem, eamque impellit versùs orific ium B, &longs;uper­nè verò aer penetrando cauita­tem fi&longs;tulæ, AB contrario ni&longs;u re­pellit &longs;ummitatem aquæ F intr&atail; orificium B in&longs;inuatam: quia ve­rò fieri non pote&longs;t vt contactus, & a&longs;peritates internæ fi&longs;tulæ non impediant de&longs;cen&longs;um, & ni&longs;um compre&longs;&longs;iuum aeris, fit vt minori momento aer per fi&longs;tulæ canaliculum pertran&longs;iens premat aquæ &longs;um­mitatem F, quàm liber aer externus à nullo impedi­mento debilitatus; igitur aqua F à validiori vi impul­&longs;iua aeris externi impelli &longs;ursùm debet, & in&longs;inuari intra fi&longs;tulam à B ad C. quou&longs;que minor vis aeris per AC tranfeuntis vnà cum pondere aquæ CB æquili­brentur momento totali aeris externi, quapropter exce&longs;&longs;us momenti totalis aeris non impediti &longs;upr&atail; momentum aeris debilitati æqualis e&longs;t ponderi aquæ CD.

Debemus modò fal&longs;itatem huius &longs;ententiæ o&longs;ten­dere. Reuoluatur fi&longs;tula AB vnà cum aqua contenta CD inuer&longs;o &longs;itu, vt &longs;upina eius pars A fiat prona, tunc aer infernè per prolixum canaliculum AC immi&longs;&longs;us non &longs;ecùs ac priùs impeditur à contactibus, & a&longs;pe-

ritatibus internis vitri, & ideò eodem debiliori, & imminuto momento pellit aquam CD &longs;ursùm, impe­ditque eius de&longs;cen&longs;um. E contrà aer &longs;upernè nil fe­rè impeditus premit deorsùm aquam D orificio B pe­nè contiguam, igitur non &longs;ecùs, ac priùs aer totali momento eius deorsùm impellit aquam DC: ab hoc verò momento non &longs;ubtrahitur, immò ei additur pon­dus aquæ DC, igitur momentum, quo aqua DC im­pellitur deorsùm maiori exce&longs;&longs;u, nempè duplò &longs;upe­rat vim, qua &longs;ursùm repellitur, &longs;cilicèt æqualis e&longs;t duplo ponderis aquæ DC, &longs;ed priùs medietas pr&ecedil;di­cti exce&longs;&longs;us, non ob&longs;tante fi&longs;tulæ interna ariditate, a­quam &longs;ursùm celeri motu eleuauerat, igitur multò ce­leriùs, & faciliùs in &longs;ecundo ca&longs;u à duplici exce&longs;&longs;u vir­tutis motiu&ecedil; deprimi aqua DC deorsùm deberet per aridum canalem CA, &longs;ed hoc e&longs;t fal&longs;um, nam aqu&atail; DC quie&longs;cit, aut tardi&longs;&longs;imo motu de&longs;cendit versùs A, ergò non eleuatur aqua in fi&longs;tula ob inæquales ae­ris impul&longs;iones.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

Tandem quod interna vitri &longs;cabrities non impel­lat illam aquæ exiguam molem, &longs;atis a pertè con&longs;irma­tur ij&longs;dem rationibus adductis in fine propo&longs;itionis 183. Igitur & c.

PROP. CLXXXIV.

Quare aqua ab ima fi&longs;tulæ parte in aere con&longs;titutæ non de&longs;luat rationem reddere.

MOdò remanet difficultas, quare &longs;cilicèt in infi­mo fi&longs;tulæ confinio in aere con&longs;titutæ impe-ditur aquæ defluxus; & licet videatur hoc à contactu aeris fieri, nihilominùs ex no&longs;tris principijs dici po­te&longs;t, quod in infimo fi&longs;tul&ecedil; orificio machinulæ lanugi­nis particularum aquæ inter &longs;e connexæ di&longs;trahuntur, & ideo tenaciori re&longs;i&longs;tentia vinciuntur, & efficiunt veluti rete adhærens extremo fi&longs;tulæ, & quia vis pr&ecedil;­dictarum machinularum violenter di&longs;tractarum ma­ior e&longs;t vi ponderis exigui aquæ intra fi&longs;tulam conten­, hinc &longs;equitur aquæ quies, eodem pror&longs;us modo, ac &longs;u&longs;tinentur guttæ aqueæ è ramis arborum pen­dentes.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXXV.

Re&longs;tat modò cau&longs;a motiua, à qua &longs;ur&longs;um impellitur aqua in fi&longs;tulis.

QVæ meo iudicio ex theoria nuper expo&longs;ita pen­det, quia nempe in cauitatibus &longs;ubtilium fi&longs;tu­larum internus aquæ contactus grandis e&longs;t, & amplus re&longs;pectu illius aquæ moleculæ ibidem exi&longs;tentis, er­go &longs;ubitò ac infimum fi&longs;tulæ orificium attingit aquam efficitur in eius interno, & cauo perimetro efficaci&longs;­&longs;imus contactus à cuius adhæ&longs;ione fulciri &longs;u&longs;tineri­què pote&longs;t maius pondus, quàm habet pu&longs;illa aquæ particula in&longs;inuata, & ideo gradus prædictæ virtutis &longs;u&longs;pen&longs;iuæ, & adhæ&longs;ionis exercetur in aqua &longs;ubicta, & proinde ea reddetur aliquo pacto leuis, &longs;eu minùs pondero&longs;a, quàm &longs;it aqua collateralis liberè premens. Et quia minimæ aquæ particulæ poro&longs;itatibus, & a&longs;-peritaribus internis fi&longs;tulæ innixæ efficiuntur operan­turque vt totidem vectes, quæ flecti po&longs;&longs;unt, & internè rotari, nece&longs;sè e&longs;t vt partes aquæ collaterales magis compre&longs;&longs;æ à totali energia &longs;ui ponderis vim faciant impellendo &longs;ursùm particulas illas aquæ, quæ minùs comprimuntur à vectibus &longs;upradictis, & ideo rotando excurrere po&longs;&longs;unt interiùs efformando tumorem, vel monticulum aqueum, qui excurrendo lateralitèr al­tioribus fi&longs;tulæ poro&longs;itatibus in&longs;inuabitur, adhære­bitque, & ideò denuò imminuetur|eius vis compre&longs;&longs;i­ua, renouabiturque cau&longs;a vlterioris &longs;u&longs;pen&longs;ionis, & proindè altiùs aqua intra fi&longs;tulam impelletur, & &longs;ic de nouo eminentioribus lateribus adhærendo &longs;uc­ce&longs;&longs;iuè altius impelletur, quou&longs;que ad &longs;upremam, & maximam illam altitudinem aqua perducta, in qu&atail; æquilibrium cum aqua collaterali liberè premente efficiatur, tunc quidem quies eius &longs;ub&longs;equetur, nec vlteriùs eleuari poterit.

Ex pro. 174.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Prop. 182.

PROP. CLXXXVI.

Noua phænomena ex eadem ne&longs;tra theoria &longs;aluantur, & reijcitur vis aeris ab hac operatione.

SEd pro clariori huius rei intelligentia ph&ecedil;menon nupèr à me ob&longs;eruatum in medium adduca&mtail;, Sit fi&longs;tula &longs;tricta vitrea AB hæc quidem arida perpen­dicularitèr aquam contingens eam eleuet per &longs;patium BF; &longs;i verò internè fi&longs;tula priùs humectata fuerit, & deindè exinanita, in contactu aquæ &longs;ubiectæ altiùs eleuatur per &longs;patium BE; &longs;i po&longs;teà eadem fi&longs;tul&atail; pro&longs;undiùs demergatur infra aquam, vel inclinetur,

aqua exucta maius &longs;patium BC occupa­bit. His po&longs;itis tran&longs;portetur integra fi&longs;tu­la vnà cum aqua contenta ab aqua ad aerem, perpendicularitèr tamen erecta ad planum horizontis tunc effluere cunctanter con&longs;pi­citur ab infimo orificio B guttula quædam, quæ &longs;en&longs;im colligitur, tume&longs;citque; & hoc contingit quando valdè excedens e&longs;t alti­tudo aqu&ecedil; BC, at &longs;i non nimia fuerit, quie&longs;cet in &longs;itu perpendiculari ab&longs;que eo quòd ex orificio B defluat noua aquæ gutta. Modò dum aqua &longs;upra terminum E versùs C per&longs;euerat orificium fi&longs;tulæ B contingat aquam va&longs;is, vel guttulam D &longs;u­&longs;pen&longs;am à palma manus, vel adhærentem externæ, & extremæ parti ip&longs;ius fi&longs;tulæ B, videbis aquam BC deprimi deorsùm v&longs;que ad E, vbi nimirùm con&longs;i&longs;te­bat aqua exucta è va&longs;e, quando interna cauitas hu­mectata fuerat; è contrà &longs;i altitudo aqu&ecedil; internæ val­de diminuta fuerit, vt BG, tunc quidem in contactu guttulæ inferioris augetur eius altitudo exugendo nimirùm aquam ip&longs;ius guttulæ D.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Ratio huius admirandi effectus videtur pendere ex legibus æquilibrij aquæ externæ, & internæ. pri­mò quando gutta pendula D adhæret in&longs;imo fi&longs;tulæ orificio, concipere debemus &longs;uperficiem externa&mtail; prædictæ guttulæ pendentis e&longs;&longs;e veluti &longs;acculum, vel bur&longs;am compo&longs;itam ex machinulis aqueis variè con-textis, incuruatis, & di&longs;tractis à pondere totius aquæ prementis, vt alibi dictum e&longs;t, internæ verò partes eiu&longs;dem guttulæ, ob earum lubricitatem, liberè &longs;lue­re po&longs;&longs;unt intra alias aquæ particulas, orificium va&longs;is explentes. Hinc fit vt illæ exercendo liberè earu&mtail; momentum grauitatis, præualeant energiæ compre&longs;­&longs;iuæ diminutæ, ac debilitat&ecedil; particularum aquæ GB intra cauitatem vitri adhærentium, & &longs;ic &longs;ursùm im­pellantur à G v&longs;que ad F, vel &longs;i cauitas madida fue­rit v&longs;que ad E, nempè quou&longs;que fiat momentorum æquilibrium. è contrà momentum altioris aquæ BC ma­ius erit eo, quo aqua va&longs;is &longs;ubiecta, vel intra guttu­lam D contenta liberè premit, proindeque illa de­&longs;cendet in fi&longs;tula à &longs;ummitate C v&longs;que ad E, vbi ni­mirùm eorum momenta adæquantur. Sed in priori ca&longs;u for&longs;an facilè &longs;u&longs;picabitur à compre&longs;&longs;ione aeris &longs;ursùm impelli guttulam infimam à G v&longs;que ad E, cu­ius inditium e&longs;&longs;e pote&longs;t, quòd tota guttula D exugi­tur à fi&longs;tula, imò vlteriùs promouetur aere &longs;ucceden­te, & &longs;ic videtur, quòd non ab aqua externa, quæ ibi­dem non exi&longs;tit, & proinde operari nequit, &longs;ed ab aere impellitur. &longs;ed re&longs;ponderi pote&longs;t quod à vi im­petus, quo aqua in fi&longs;tula a&longs;cendit pro&longs;equi, & con­tinuari aliquanti&longs;per pote&longs;t a&longs;cen&longs;us po&longs;tremæ par­ticulæ guttæ ip&longs;ius D, quatenus à glutine machinu­larum aquæ connectuntur po&longs;trem&ecedil; illæ guttulæ par­tes, cum præcedentibus, & ab impetu earum partium, quæ actu in fi&longs;tula mouentur &longs;ursùm, trahantur vlte­riùs, & con&longs;equentèr aer po&longs;tea &longs;uccedat in &longs;patio infimo fi&longs;tulæ inani ab aqua derelicto.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Cap. 8 cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXXVII.

Aqua in fistula magis demer&longs;a non debet altiùs eleuari quàm in ca quæ aquam, aut aerem tangit.

SEd procedamus ad præcipuam difficultatem, ex cuius &longs;olutione reliquis omnibus &longs;atisfiet. Sit vas RSV aqua plenum, &longs;umanturque duæ fi&longs;tulæ æ­quales, & æquè amplis cauitatibus perforatæ, vtrin­que apertæ, vna quidem AB profundiùs demergatur infra aquæ libellam RV; reliqua verò EH tantum­modò &longs;uperficiem aquæ RV contingat, & ambo per­pendicularitèr in&longs;i&longs;tant &longs;upremo

plano aquæ RV. Si ergo veru&mtail; e&longs;t, quòd aqua collateralis magis compre&longs;&longs;a à totali eius momento qualis e&longs;t cylindrus aqueus FI comparatus cum aqua BC, quæ minus comprimit &longs;ubiectam aquam, eò quòd &longs;u&longs;penditur, &longs;u&longs;tentatur­que ab internis vitri a&longs;peritati­bus, redditurque aqua CB veluti virga lignea re&longs;pectu aquæ colla­teralis FI; ergo quò profundiùs demergitur fi&longs;tul&atail; longior e&longs;t virgula minùs grauis aquea BC, & ideò, ex demon&longs;tratis, validiori vi &longs;ursùm impelletur ab a­qua collaterali FI, quàm impellatur &longs;ursùm exiguus cynndrulus aquæ H, qui fu&longs;tinetur, & comparatur cum aqua &longs;uperficiali RV.

Pr. 95.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

Sed re&longs;pondetur, quòd aqua CB non redditur le­uior ob internum contactum fi&longs;tulæ, nam intern&atail; fi&longs;tulæ &longs;uperficies cùm &longs;it madida, nihil, aut paru&mtail; impedit vim grauitatis aquæ contentæ intra fi&longs;tulam BC, & hoc experitur cùm in aere trans&longs;ertur fi&longs;tula, tunc enim aqua intra cauitatem eius madidam libe­rè mouetur de&longs;cend it que; præcipuum verò impedi­mentum in extremo orificio fi&longs;tulæ B experitur, non intra aquam, &longs;ed po&longs;tquam aerem attingit; non qui­

dem à vi ela&longs;tica, vel ponder&etail; eiu&longs;dem aeris, &longs;ed quia tunc i&ntail; aqua ad confinium B perducta effi­citur rete &longs;uperiùs expo&longs;itum, qua­tenùs particul&ecedil; infernæ illius aqu&ecedil; vici&longs;&longs;im connexæ dum pendent à vi propri&ecedil; grauitatis di&longs;tract&ecedil; ea­rum machinulæ paritèr maiorem violentiam patiuntur, & ideò ma­iori vi vici&longs;&longs;im connectuntur, & &longs;ic re&longs;i&longs;tere violentiæ pre&longs;&longs;ionis aquæ po&longs;&longs;unt; at in ca&longs;u no&longs;tro exi&longs;tente orificio B demer&longs;o infra aquam non pote&longs;t effici rete illud ro­bu&longs;tum aptum ad &longs;u&longs;tinendam aquam incumbentem, quia non di&longs;trahuntur machinulæ aquæ B exi&longs;tentes, & contingentes internam aquam va&longs;is RSV: hinc fit vt facilè vna aquæ pars &longs;uper aliam &longs;ibi contigua&mtail; excurrere valeat, & hinc deducitur ratio quare i&ntail; fi&longs;tula EH vnà cum aqua HK excedente con&longs;uetam altitudinem, &longs;i tota in aere con&longs;tituta fuerit, altiùs prædictam aquam &longs;u&longs;tinebit, quàm &longs;i aquæ libellam RV tetigerit, tunc enim de&longs;cendit à K ad G, & HG altior erit quàm DC, &longs;cilicèt quando fi&longs;tula profun­diùs mergitur, vt in B; quia nimirum dum in aere ex­tabat, efficiebatar rete prædictum, cùm verò aquam &longs;ubiectam contingit, tum connexio illa tenax facilè &longs;oluitur diffluitque, & &longs;ic non ampliùs &longs;u&longs;tinere tan­tum pondus incumbens pote&longs;t.

Cap. 8. cur exiguæ aquæ guttæ &longs;upra libellam aquæ a&longs;cendunt.

Id ip&longs;um præterea confirmatur, quia in contactu aquæ in H &longs;u&longs;penditur circa fi&longs;tulam externè monti­culus quidam aqueus &longs;upra libellam RV, quod con­&longs;equenter &longs;uadet aquam a vi contactus vitri externi &longs;u&longs;pendi ni&longs;u contrario eius, qui à grauitate aquæ exercetur, & proindè aqua prædicto monticulo &longs;ub­iecta, & annexa leuior redditur, igitur aqua infr&atail; orificium &longs;ubiectum fi&longs;tulæ ob prædictam &longs;u&longs;pen&longs;io­nem minùs grauis facta, nece&longs;sè e&longs;t, vt eleuetur ab integro momento collateralis aquæ liberè premen­tis, & &longs;ic in&longs;inuetur intra cauitatem fi&longs;tulæ &longs;upra a­quæ &longs;ubiectæ libellam quou&longs;que fiat momentorum æquilibrium.

Ex hac theoria facilè re&longs;oluuntur circum&longs;tantiæ, quæ in operationibus prædictarum fi&longs;tularum ob&longs;er­uantur, & &longs;imul magis confirmatur doctrina &longs;uperiùs expo&longs;ita.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

PROP. CLXXXVIII.

In fi&longs;tulis strictioribus altiùs aqua eleuari debet, quàm in latioribus, & in fistulis æqualibus, &longs;ed in æqualiter ad aquæ &longs;uperficiem inclinatis aqua ad eamdem altitudinem eleuatur.

ET primo loco percipitur quare in fi&longs;tulis latio­ribus aqua ad minorem altitudinem eleuatur, quàm in &longs;ubtili&longs;&longs;imis, & angu&longs;ti&longs;&longs;imis canalibus: & e&longs;t, quia adhærentia, & connexio aquæ parietibus internis canalium maiorem proportionem ad molem aquæ in&longs;inuatæ exten&longs;iuè, & inten&longs;iuè in canaliculis &longs;ubtili&longs;&longs;imis, habet quàm in amplis, & capacioribus. Et quoad exten&longs;ionem pertinet, quia vis adhæ&longs;ionis men&longs;uratur à contactibus, & ideò à &longs;uperficie inter­na canaliculorum, è contrà re&longs;i&longs;tentia men&longs;uratur à pondere cylindri aquei contenti in ij&longs;dem canalicu­lis, e&longs;tque proportio cylindrorum aqueorum eiu&longs;dem altitudiais duplicata eius rationis, quam habent eo­rum perimetri |interni, igitur quanto magis cre&longs;cit interna canalis amplitudo, tantò magis minuitur ad­hæ&longs;io, & augetur re&longs;i&longs;tentia ponderis ip&longs;ius aquæ con­tentæ. Imminuitur po&longs;teà gradus inten&longs;iuus internæ adhæ&longs;ionis, proptereà quod, vt dictum e&longs;t &longs;upra, non e&longs;t æquè valida facultas, & energia adhæ&longs;ionis aqu&ecedil;, & connexionis|cum parietibus internis |in |vniuer&longs;o illo argine montuo&longs;o, &longs;ed e&longs;t minus efficax, quantò magis ab internis parietibus remouetur. Modò i&ntail; fi&longs;tulis amplioribus aqua contenta versùs axim caui­tatis eius magis recedit à &longs;uperficie interna fi&longs;tulæ dilatatæ, quàm in fi&longs;tula &longs;trictiori, & ideò in illa de­biliùs aqua &longs;u&longs;tinebitur &longs;u&longs;pendeturque, & quantò minor e&longs;t vis &longs;u&longs;tinens, & eleuans re&longs;pectu ponderis fluidi contenti, tantò debet imminui &longs;ublimitas eius eleuationis, vbi præcisè efficitur æquilibrium &longs;upe­riùs expo&longs;itum.

In fine prop. 182.

Cap. 8. cur exiguæ aqu&ecedil; guttæ &longs;upra libellam aquæ a&longs;cendunt.

Similitèr in eodem canaliculo ad horizontem in­clinato longiori &longs;patio eleuabitur aqua, quàm &longs;i per­pendicularitèr horizonti in&longs;i&longs;teret, quia nimirùm &longs;u­blimitas verticalis in vtroque ca&longs;u eadem e&longs;&longs;e debet, cùm in &longs;itu inclinato momentum aqu&ecedil; prementis men­&longs;uretur non ab vniuer&longs;a longitudine, aut ponder&etail; ab&longs;oluto cylindri aquei &longs;ubleuati, &longs;ed ab eius verti­cali eleuatione, & propterea tantumdem præcisè im­pelletur ab eadem cau&longs;a eleuante non alterata, &longs;cili­cèt à pondere ab&longs;oluto aquæ collateralis liberè pre­mentis.

Quare præ­dictæ opera­tiones non contingant ni&longs;i fi&longs;tulæ &longs;int vtrinque apertæ.

Et hæc omnia contingere debent quotie&longs;cumque canaliculus &longs;upernè non clauditur; Si enim ob&longs;tru­ctus fui&longs;&longs;et aer idem internè comprehen&longs;us impediret aqu&ecedil; a&longs;cen&longs;um, quia non po&longs;&longs;et aqua in&longs;inuari ab&longs;que eo quod contentus aer &longs;tringeretur conden&longs;aretur­que, cumque aer conden&longs;ari con&longs;tiparique nequeat, ni&longs;i à noua cau&longs;a violentèr eum conden&longs;ante, cui aer &longs;ua vi ela&longs;tica re&longs;i&longs;tit, igitur &longs;i aqua intra prædictam fi&longs;tulam ingrederetur, con&longs;tringere aerem internu&mtail; deberet, & propterea idem aer &longs;ua vi ela&longs;tica impe­dict prædictum ingre&longs;&longs;um.

Cap. 9. de corpn&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

De corpu&longs;culorum innat antium mutuo amplexu, atque fuga.

CAP. IX.

SVnt ferè triginta duo anni, cùm ego experiri vo­lui an filamenta ferrea &longs;uper aquam innatanti&atail; in diuer&longs;is ad meridianam inclinationibus elongata retinerent eandem po&longs;ituram, ad eamdenque &longs;ituatio­nem, directionemque redigerentur in qua fabrefacta fuerant, vt Guglielmus Gilbertus ait, & dum hoc at­tentiùs ob&longs;eruarem, mirabile &longs;pectaculum &longs;e&longs;e obtu­lit hactenùs non animaduer&longs;um, quod nimirùm ali­quæ extremitates natantium corporum auido cur&longs;u &longs;e vniebant, amplectebanturque, aliæ verò &longs;egrega­bantur non &longs;ecùs, ac in magnete, & ferro contingit: igitur ab hac nouitate excitatus idip&longs;um comproba­ui adhibitis alijs corpu&longs;culis, fe&longs;tucis, folijs arborum, & innumeris alijs corporibus; cùmque ego &longs;ummo­perè optarem cau&longs;am prædicti effectus perciper&etail;, po&longs;t innumera experimenta, animaduerti huiu&longs;modi operationes contrarias de­

pendere ab aqueis arginibus circa corpora natantia adia­centia, aliquando eminenti­bus, aliquando depre&longs;&longs;is. Sump&longs;i duas laminulas æreas papyro graciliores, quales &longs;unt V, & X, & in earum punctis intermedijs C, & L appo&longs;ui duas fe&longs;tucas CD, & LM, ibidemque cera eas ferru­minaui perpendicularitèr erectas ad plana laminula­rum. appo&longs;ui po&longs;tea laminas &longs;upra aquam va&longs;is FRSO horizontali applicatione, quæ infra aquæ libella&mtail; innatando deprimebantur, efficiebantquè circumcir­cà argines aqueos EA,
GB, nec non IN, KO; po&longs;teà efformaui duas a&longs;&longs;ulas ligneas Y, & Z, quarum altitudines &longs;e­midigitum ferè æquabant, ij&longs;dem quoque &longs;e&longs;tucas per pendiculariter adaptaui, po&longs;iti&longs;que &longs;uper aquam erigeban­tur circà earum perimetrum montuo&longs;itates quædam decli­ues, vt EA, GB &longs;upra vniuer&longs;alem aquæ libellam FHO. His præparatis &longs;olertèr digitis impuli &longs;ummitate&mtail; D fe&longs;tucæ approximando laminulam V versùs X, ean­que firmitèr retinendo antequam ad contactum al­teriùs laminæ V perueniret, eratque di&longs;tantia inter laminas minor latitudine vnius digiti, tunc primò vi­di &longs;ponte &longs;ua duas laminas V, & X &longs;e&longs;e mouere vn&atail; versùs alteram, & licèt mediocri violentia digitis re­tinerentur, impedireturque acce&longs;&longs;us earum, po&longs;te&atail; non minùs, quàm priùs veloci cur&longs;u &longs;e mutuò ample­ctebantur, &longs;ed in ip&longs;o actu coniunctionis earum om­ninò explanabatur monticulus GHN aqu&ecedil;, quo priùs &longs;egregabantur, po&longs;tea me conuerti ad a&longs;&longs;ulas ligneas, Y, & Z quæ paritèr immobiles, & inertes erant quan­do ab inuicem di&longs;tabant &longs;patio maiori, quàm digita-li, &longs;ed magis appropinquata vna versùs alteram, &longs;u­bitò a&longs;&longs;ulæ excurrebant ad &longs;e &longs;e amplectendum, & hìc accidit operatio diuer&longs;a à præcedenti, nam duæ montuo&longs;itates eleuatæ GB, & IN nedùm non &longs;e ex­planarunt, nec redegerunt ad aquæ &longs;ubiectæ libellam FH de&longs;cendendo, &longs;ed è contrà &longs;patium intermedium, & cauitas BHI omninò repleta e&longs;t v&longs;que ad &longs;upremum culmen BI. Tandem coniunxi laminam æream V cum
a&longs;&longs;icula Z, & vidi, quod quotie&longs;cumque approxi­mabantur ad di&longs;tantia&mtail; digito minorem, nedùm &longs;e mutuò non amplecteban­tur, &longs;ed è contra vna rapi­dè ab altera effugiebat, fegregabaturque, qua&longs;i a­bominaretur con&longs;pectum, & viciniam illius. Quaprop­ter experientia con&longs;tat, quòd acce&longs;&longs;io, approximatio, & amplexus laminularum, tunc &longs;olummodò accidit, quando argines aquei &longs;imiles &longs;unt inter &longs;e, &longs;cilicèt quando ambo sunt eleuati, vel vterque depre&longs;&longs;us e&longs;t in­tra aquæ va&longs;is libellam; &longs;ed quando argines aquei sunt contrario ordine di&longs;po&longs;iti, vnus quidem depre&longs;&longs;us, alter verò eleuatus &longs;upra aquæ libellam, tunc effici­tur a&longs;&longs;ularum &longs;eparatio, & fuga. Et in omnibus præ­dictis operationibus experitur, quod &longs;i vna prædi­ctarum laminularum fixè, & in quiete retineatur, &longs;eù potiùs in ori&longs;icio va&longs;is exi&longs;tat, reliqua laminula li­bera, & non retenta, aut accedet, aut fugiet conta-ctum alterius laminæ immobilis; cùm verò ambo li­berè in fluido innatant, tunc motus e&longs;t communis in vtroque corpore, cum hac tamen differentia, quòd corpus minùs amplum, & minùs pondero&longs;um veloci­orimotu, aut accedit, aut refugit à reliquo, cum è contrà agitatio amplioris laminæ tardi&longs;&longs;imo, & lan­guido motu fiat. Et hæc e&longs;t vera, & accurata hi&longs;toria huius admirandi effectus. non igitur miror veram cau­&longs;am huius effectus adductam non fui&longs;&longs;e, cùm non con­ftabat neque perfectè innotuerat hi&longs;toria huius ope­rationis, quæ tantummodò clarè, & euidentèr ob&longs;er­uari pote&longs;t mediantibus &longs;upradictis laminulis à m&etail; excogitatis.

Hi&longs;toriæ acce&longs;&longs;us, & rece&longs;&longs;us cor porum inna­rantium cum omnibus &longs;u is circuman­tijs affer­tu.

Cap. 9. de corpu&longs;culo­rnm innatan­tium mutuo amplexu |at­que fuga.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Hanc experientiam Amicis communicaui, quorum quamplurimi adhùc viuunt, tùm in Sicilia, tùm Romæ. po&longs;te à anno 1655 Florentiæ Sereni&longs;&longs;imo Ferdinando Magno Duci, & Principi Co&longs;mo Hetruriæ, ac Mæ­cnati optimo, &longs;apienti&longs;&longs;imoque Leopoldo Cardi­nali Mediceo, qui humani&longs;&longs;imè nuperis &longs;uis literis huius meæ o&longs;ten&longs;ionis, & ratiocinij à me tunc tem­poris adducti &longs;e optimè recordari &longs;crip&longs;it. In&longs;titut&atail; po&longs;tea Experimentali Academia Medicea publicè &longs;o­cijs illis docti&longs;&longs;imis eamdem experientiam o&longs;tendi, & innumeris præclaris viris variarum nationum, qui­bus præcipiente Sereni&longs;&longs;imo Cardinali offeebatur &longs;pectaculum &longs;electiorum experimentorum prædictæ Academiæ.

Præter iam dictas nouitates aliam po&longs;tea ob&longs;eruaui àcau&longs;a longè diuer&longs;a pendentem pro cuius intelli-gentia recen&longs;eri priùs debet effectus &longs;atis vulgatus duarum laminularum ex vitro exqui&longs;itè explanato, & luigato, quæ &longs;ibi mutuò congruunt, atque exo&longs;cu­lantur, amplxanturque tanta tenacitate vt &longs;i &longs;upre­ma horizonti parallela &longs;ursùm eleuetur, pariter &longs;uc­cedit, trahiturque alia lamina contigua inferior, &longs;u­&longs;tineturque pendula, non &longs;ecùs, ac &longs;i e&longs;&longs;et &longs;uperiori connexa conglutinataque, quod &longs;i &longs;uperna vitrea la­minula pauli&longs;pèr ad planum horizontis inclinetur, tunc &longs;ubitò inferior laminula excurret versùs partem decliuem plani &longs;uperioris ab&longs;que eo quod à &longs;uprema lamina diuellatur, &longs;ed &longs;emper illi adhærendo de&longs;cen­det impul&longs;a ab in&longs;tinctu naturali, quo grauia conan­ &longs;emper magis ad centrum grauium accedere eo modo, quo po&longs;&longs;unt, &longs;cilicèt via inclinata, cum directa, & perpendicularis fuerit impedita.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

PROP. CLXXXIX.

Si duæ aquæ guttulæ mobiles &longs;e mutuo tangant lateraliter, hæ non quie&longs;cent, &longs;ed lateralitèr excurrent quou&longs;que ver­tices earum in eadem recta perpendiculari ad horizontem extiterint.

HOc &longs;uppo&longs;ito &longs;int duæ guttulæ aquæ ABC, vna pendula ex lamina horizontali AC &longs;u&longs;pen&longs;a filo DE, & alia FGH eleuata &longs;upra a&longs;&longs;ulam LM innatantem &longs;uper aquam RS, tunc &longs;i vertex B &longs;uperioris guttulæ continget &longs;ummitatem G guttulæ inferioris, duæ gut­tularum &longs;uperficies horizonti æquidi&longs;tantes G, & B &longs;ibi mutuò congruent, & proindè nulla ratio &longs;uadet vt guttulæ ip&longs;æ, & con&longs;equen tèr a&longs;&longs;iculæ lateralitèr moueantur, cùm earum neutra

vim motiuam habeat horizon­talem, propterea quòd &longs;i mo­uerentur horizonti æquidi&longs;tan­ter non magis, quam priùs cen­tro grauium approximarentur, neque mos e&longs;t naturæ fru&longs;trà operari.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Fiat deindè contactus guttularum lateralis, &longs;cili­cèt &longs;uperficies &longs;ini&longs;tra AB, &longs;upremæ pendulæ guttu­læ tangat &longs;uperficiem dextram GH inferioris guttu­læ, tunc efficietur contactus, & &longs;uperficierum con­gruentia, non in vnico puncto &longs;icuti configuratio ea­rum tumida, & conuexa requireret, &longs;ed in &longs;atis &longs;en­&longs;ibili &longs;patio veluti e&longs;t IK, & hìc efficitur adhæ&longs;io, & congruentia inter duas aque as partes non minori te­nacitate, quam duæ laminæ vitreæ &longs;uperiùs expo&longs;itæ &longs;e &longs;e mutuò necte bantur, itaque difficile diuelluntur prædictæ aquæ vna ab altera, &longs;ed facillimè pote&longs;t v­na &longs;uper&longs;icies &longs;uper alteram excurrere, vt aquæ &longs;lu­xibilitas requirit, igitur quia prædictæ guttulæ effi­ciunt contactum IK obliquum, & decliuem versùs centrum telluris, nece&longs;sè e&longs;t vt guttula inferior gra­uis FGH exerceat natiuam &longs;uam vim de&longs;cen&longs;iua&mtail; eo modo quo pote&longs;t, & ideò dilabetur, fluetque de­orsùm &longs;emper tamen &longs;uperiori guttulæ adhærendo, & hoc eò v&longs;que fiet, quou&longs;que ad infimum &longs;itum de-cliuitatis AB peru eniatur: non pote&longs;t verò deorsù&mtail; illa fluere dilabique ab&longs;que eo quod eius vertex G versùs culmen B approximetur; neque huiu&longs;modi approximatio fieri pote&longs;t ab&longs;que eo quod lamin&atail; &longs;ubiecta LM innatando lateralitèr moueatur versùs S, & &longs;uprema lamina AC excurrat aliquanti&longs;pèr ver­sùs R, igitur nece&longs;sè e&longs;t, vt ambæ laminæ moueantur lateralitèr, & propriùs ad &longs;e &longs;e accedant, & tunc præ­cisè quie&longs;cent, nec vlteriùs &longs;e promouebunt, quan­do præcisè obliquitas de&longs;cen&longs;us terminatur, &longs;cilicèt quando vertex G inferioris guttulæ præcisè congruit, adhæretque extremitati B guttulæ &longs;upremæ, & tunc pr&ecedil;dicti vertices aliquo pacto explanantur, efficiun­turque horizonti æquidi&longs;tantes, quod efficitur me­diante vnione notabilis &longs;uperficiei in vtraque gut­tula, vnde &longs;equitur effectus quietis &longs;uperiùs expo­&longs;itus,

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Tran&longs;eo iam ad alia experimenta difficiliora, pro quorum declaratione præmitti debent aliqua lem­mata tum ex hydro&longs;taticis, cùm ex mechanicis.

PROP. CLXXXX.

Corpus molle, vel fluidum intra aliud grauius fluidum de­mer&longs;um ne dum ab hoc &longs;ursùm exprimitur, &longs;ed etiam later ali motu eius partes &longs;tringuntur.

COn&longs;tat ex coroll. prop. 10. fluidi naturam con­&longs;i&longs;tentis talem e&longs;&longs;e vt partium eius inferiorum æquabilitèr di&longs;po&longs;itarum, &longs;cilicèt horizontalitèr in-ter &longs;e connexarum partes illæ, quæ &longs;unt magis pre&longs;­&longs;æ, impellant, ac&longs;ubleuent alias partes collaterales &longs;ursùm, &longs;i fuerint minùs compre&longs;&longs;æ. Sed oporter&etail; ait, Archimedes, vt conatus, & impul&longs;us fluidi pre­mentis fiant per lineas ad horizontem perpendicu­lares. Hoc profectò veri&longs;&longs;imum e&longs;t quotie&longs;cumqu&etail; innatet intra aquam pri&longs;ma aliquod con&longs;i&longs;tens, & durum; At &longs;i in va&longs;e BCEI aqua pleno intra &longs;patium AIFG collocatur non pri&longs;ma ligne­

um, &longs;ed aliud corpus molle, vel flui­dum cedens minùs graue &longs;peci&etail;, quàm &longs;it aqua collateralis, tunc ne­dùm fluidi IG &longs;ursùm perpendicu­laritèr impelletur &longs;uperficies FG versùs IA, &longs;ed præterea latus eius AG propelletur con&longs;tringeturque versùs IF, itaut eo­dem tempore, fluidum minùs graue IG &longs;imùl a&longs;cen­dat perpendicularitèr versùs IA, & lateralitèr quo­que ab AG versùs IF tran&longs;portetur. Hinc colligitur, quod aqua, &longs;eù quodlibet fluidum BG grauius &longs;pe­cie, quàm corpus IG nedum vim facit premendo per­pendicularitèr, &longs;ed etiam vim exercet lateralitèr non quidem per horizontales lineas BA, & HG, &longs;ed per lineas inclinatas BK, & LG, & hoc &longs;uppleri Archime­deo a&longs;&longs;umpto debere cen&longs;eo, cùm in&longs;tinctu naturæ corpora omnia grauia de&longs;cendere conentur versùs terræ centrum, qulbu&longs;cumque modis hoc ab eis con­&longs;equi po&longs;&longs;it, nedum itinere perpendiculari ad hori­zontem, &longs;ed etiam inclinato.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

De in&longs;identi­bus humido lib. 1.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Hoc po&longs;ito, &longs;i in eodem va&longs;e exi&longs;tente aqua in &longs;pa­tio ABHG intelligatur collaterale pri&longs;ma AGFI ab aere repleri, vel à quolibet alio fluido minùs graui &longs;pecie, quàm &longs;it ip&longs;a aqua, tunc paries aqueus AG nullo pacto &longs;u&longs;tine bitur in eodem &longs;itu erectus, &longs;ed dilabetur &longs;&longs;uetque è &longs;upremo loco A versùs infimum F, neque oppo&longs;itum vnquàm contingere po&longs;&longs;et, vt &longs;cilicèt per&longs;euerante pariete aqueo AG erecto de&longs;cen­deret infra libellam GH, & deinde motu re&longs;&longs;exo &longs;ursùm perpendicularitèr aquæ infimam libellam FG versùs IA propelleret perpendiculari motu, profe­ctò hoc contigeret &longs;i inter aquam, & aerem ade&longs;&longs;et paries ligneus, à quo impediretur effluuium aquæ in­tra foueam AF; atnullo pariete interpo&longs;ito videtur omninò impo&longs;&longs;ibile vt aqua non defluat motu incli­nato ad replendam cauitatem aream AF. Hocqu&etail; confirmatur euidenti experientia; fiat bur&longs;a coria­cea parallele pipeda &longs;ursùm aperta ad in&longs;tar putei, & dilatatis quatuor eius angulis digitis, vel virgis, immergatur bur&longs;a aere plena intra aquam; videbis, quod nedùm ba&longs;is, & fundum, &longs;ed etiam quatuor fa­cies collaterales bur&longs;æ incuruantur conuexè versùs intermedium axim eiu&longs;dem putei, & &longs;i &longs;imùl digiti, aut virgulæ educantur, nec ampliùs vim exerceant, nedùm bafis, & fundum putei a&longs;cendet &longs;ursùm, &longs;ed etiam eius parietes collaterales &longs;e &longs;e con&longs;tringent, & ad &longs;e &longs;e inuicem accedent, quod e&longs;t euidenti&longs;&longs;imum &longs;ignum, aquam nedùm vim facere &longs;ursùm perpendi­cularitèr aerem expellendo, &longs;ed etiam lateralitèr

conari excurrere per lineas obliquas con&longs;tringendo laterales parietes prædicti putei coriacei. Hinc in­ferre licèt, quòd &longs;i magis flexibiles, & cedentes fiant parietes prædicti putei, &longs;emperque magis attenuen­tur, quou&longs;que fiant indiui&longs;ibiles, qualis profectò e&longs;t paries di&longs;tinguens aquam ab aere, tunc idip&longs;um con­tinget, &longs;cilicèt aqua defluet motu tran&longs;uer&longs;ali obli­quo intra cauitatem aeream AF.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Si po&longs;tea loco aeris repleatur eadem fouea AIFG alio fluido minùs graui &longs;pecie, quàm &longs;it ip&longs;a aqu&atail; BG, v.g. repleatur oleo, dubitandum non e&longs;t idipsum contingere, &longs;cilicèt nedùm ba&longs;is FG perpendicula­ritèr &longs;ursùm eleuabitur, &longs;ed etiam paries AG, &longs;eù con­finium aquæ communis, & olei motu rran&longs;uer&longs;ali im­pelletur versùs IF.

PROP. CXCI.

Si vna pars eiu&longs;dem aquæ maiori momento &longs;ubiectum flui­dum compre&longs;&longs;erit, quàm alia eius pars collateralis, hæc an&longs;uer&longs;ali motu ab illa impelletur, &longs;ecum tran&longs;portan­do corpu&longs;cula &longs;uper eam innatantia.

ET hìc notandum e&longs;t non debere &longs;emper fluidum in &longs;patio AF contentum rarius, & di&longs;trahibilius e&longs;&longs;e, quàm &longs;it fluidum AH. Sed etiam &longs;i fuerit ma&longs;&longs;a aquea eiu&longs;dem con&longs;i&longs;tentiæ, ac e&longs;t BG, dummodò pondus, &longs;eù momentum fluidi BG maius &longs;it grauita­te alterius fluidi AF, impelletur quoque &longs;uperficies AG (à qua fluida &longs;eparantur) tran&longs;uer&longs;ali motu ver- [missing] [missing] [missing] [missing] [missing] [missing] [missing] [missing] [missing] [missing] [missing] [missing] [missing] [missing] nus erit momento &longs;ectoris a&longs;&longs;ulæ ligneæ 4 CD, & am­bo comprimunt partes aquæ &longs;ubiectæ C6, & CZ æ­què di&longs;po&longs;itas, & in directum continuatas, &longs;cilicèt &longs;u­pra eamdem libellam horizontalem BCY, igitur la­mina innatans AC approximabitur termino Y. eadem ratione reliqua a&longs;&longs;ula lignea EH tran&longs;portabitur ver­sùs YT ab aqua &longs;ubiecta RF magis pre&longs;&longs;a, quàm col­lateralis aqua FZ, quaproptèr duæ a&longs;&longs;ulæ ligneæ AC, & EG nece&longs;&longs;ariò ad &longs;e &longs;e accedent, & &longs;emper maiori, & celeriori impetu, quò magis &longs;tringuntur coniun­gunturque, quia &longs;emper magis momentum aquæ in­terceptæ imminuitur; quod erat demon&longs;trandum.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Prop. 1.

PROP. CXCIX.

Tertio loco &longs;i duo corpora innatantia efficiant duos argines aqueos conterminales, alter depre&longs;&longs;us, reliquus vero &longs;u­pra ciu&longs;dem libellam cleuatus: hæc &longs;ibi ip&longs;is approxima­tanon vnientur, &longs;ed motibus contrarijs vnum ab altero fugiet.

IN eodem va&longs;e KVNL innatent duæ laminæ AC ænea, & EH lignea quarum centra grauitatum 4 & 7, illa deprimetur efficietque argines depre&longs;&longs;os K A, DG, hæc verò &longs;u&longs;tinebit argines eleuatos EG, & IL &longs;upra eamdem aquæ libellam KL. & &longs;iquide&mtail; prædicta duo innatantia corpora in tanta di&longs;tantia in­ter&longs;e remoueantur, vt terminus G conterminaliu&mtail; arginum DG, & GE, &longs;cilicèt &longs;ummitas illius, & alte­rius infimus terminus pertingant præcisè vniantur-que in eadem libella aquæ KL vt nimirùm figuræ cur­uæ earum in G planitiem horizontalem con&longs;tituant, tunc con&longs;tat expe­

rientia, quod in hac di&longs;tantia, & in reli­quis omnibus maio­ribus ip&longs;a DF omni­nò quie&longs;cunt prædi­cta duo corpora innatantia in eodem &longs;itu æquilibra­ta, facta eadem con&longs;tructione o&longs;tendetur vt prius (ex pr. 196.) quod momentum &longs;ectoris 4CE æqua­le e&longs;t momento portionis anuli aquei DCQG.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Accedant po&longs;tea ad &longs;e &longs;e lamina AC, & a&longs;&longs;ula EH, procùl dubio terminus communis duorum contermi­nalium arginum non habebit figuram planam hori­zonti parallelam con&longs;titutam in eadem aqu&ecedil; libella KL, vt priùs, quando nullam decliuitatem in puncto G habebant, &longs;ed nece&longs;sè e&longs;t vt efficiant montuo&longs;am eleuationem ETD valdè decliuem, quæ &longs;ecabit pla­num KL in T; & hoc patet, quia po&longs;t laminarum ap­proximationem oportet, vt &longs;upremus terminus G in­fimæ decliuitatis DG in&longs;inuetur versùs E, & recedat ab infimo termino S &longs;upremæ accliuitatis SE, in quo coniungebantur, & S, G in eodem plano libellæ KL, exi&longs;tunt; ergo G infra ES penetrando termino E, at­que S termino D approximantur, & ideò tota &longs;uper­&longs;icies 3G cadet infra &longs;uperficiem S2E, & punctum 3 cadet infra T, & punctum 2 &longs;upra idip&longs;um, cum igitur decliuitas aquæ E2 in aere &longs;u&longs;pen&longs;a h&ecedil;rere nequeat, nece&longs;sè e&longs;t vt aucta decliuitate vniatur cum infim&atail; accliuitate D3, & ideò nece&longs;sè e&longs;t vt &longs;uperficies con­po&longs;ita montis ETD &longs;it multò magis erecta, & accliuis quam priùs; & ducta perpendiculari TY &longs;upra MN, eam &longs;ecet in Y & va&longs;is fundum in Z: & quia momen­tum portionis aquei anuli CDTY maius e&longs;t momen­to eiu&longs;dem &longs;ectoris aquei anuli non imminuti CDGQ (non quidem ratione molis, cùm hæc nec iuuet in hoc negotio, nec noceat, vt dictum e&longs;t, &longs;ed quia eius mon­tuo&longs;a &longs;uperficies DTE facta e&longs;t decliuior, & magis ad perpendicularem accedens, quàm priùs); erat verò momentum integræ portionis anuli aquei CDGQ æ­qual emomento &longs;ectoris laminæ 4CD, igitur momen­tum portionis anuli aquei magis decliuis CDTY erit

maius momento &longs;e­ctoris laminæ 4CD, & premunt ambo partes aquæ &longs;ubie­ctas 4P, & CZ con­tinuatas, & æquali­ter di&longs;po&longs;itas &longs;upra idip&longs;um planum horizontale MB CY, quapropter (ex demon&longs;tratis) prædicta lamina AC di&longs;cedet, remouebiturque ab YZ. eadem ratio­ne reliqua a&longs;&longs;ula EH remoueri debet, fugereque à vi­cinia YZ, cum expelli debeat lateralitèr aqua &longs;ubie­cta RF vnà cum in&longs;i&longs;tente lamina, propterea quod à magis pre&longs;&longs;a aqua FZ expelli debet; Patet igitur duo corpora AC, & EH &longs;egregari debere, & vnum ab al­tero &longs;ugere quotie&longs;cumque duo eorum argines con-trarij aquei mutuò connectuntur, quod erat demon­&longs;trandum.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Prop. 193.

Prop. 195.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

Licèt ob facilitatem, & per&longs;picuitatem demon&longs;tra­tionis adducta &longs;int exempla corporum in quibus ar­gines eiu&longs;dem figuræ &longs;int in ambitu eiu&longs;dem corpo­ris innatantis, nihilominùs fieri pote&longs;t, vt circa vnum latus eiu&longs;dem laminæ aqua eleuetur &longs;upra eius com­munem libellam, in altera verò parte deprimatur ef­ficiendo cauam montuo &longs;itatem, hocque in lamin&atail; metallica fieri pote&longs;t inflectendo pauli&longs;pèr angulum eius: idip&longs;um in quolibet alio corpore innatante con­&longs;equi pote&longs;t, etiam ligneo, &longs;i vnus eius paries &longs;it made­factus, reliquus verò aridus, quod etiam effici pote&longs;t &longs;i vngatur &longs;ebo, vel aliqua alia &longs;imili pinguedine vna eius facies, & tunc prohiberi &longs;olet a&longs;cen&longs;us, & adhæ­rentia aquæ &longs;upra eius libellam; & in tali ca&longs;u contin­git vt idem corpus ex vna parte trahatur, ex alter&atail; verò expellatur ab alio corpore innatante, &longs;cilicèt quando argines &longs;imiles &longs;unt, aut ambo depre&longs;&longs;i, auambo eleuati, tunc efficitur acce&longs;&longs;us, &longs;ed quando ar­gines &longs;unt contrario ordine &longs;ituati &longs;equitur di&longs;ce&longs;&longs;us, & fuga vnius ab altero, & hæc omnia pendent ex ea­dem demon&longs;tratione.

In vno, co­denque corpore innatante fieri po&longs;&longs;une argines contrarij.

PROP. CC.

Sed antequam vlterius procedamus, incidentèr anim aduer­to altitudinem foueæ in aqua genitæ à de&longs;cen&longs;u laminæ grauioris &longs;pecie ip&longs;a aqua, ad cra&longs;sitiem laminæ demer&longs;æ proportionem minorem habere quàm grauitas &longs;pecifica ip­&longs;ius laminæ habet ad grauitatem aquæ in &longs;pecie.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

IN va&longs;e KVZG aqua pleno innatet lamina æne&atail; æquè cra&longs;&longs;a ABCD, quæ efficiat in aqua fouea&mtail; KBCG, cuius altitudo SC & RB. dico SC ad DC mi­norem proportionem habere quam grauitas in &longs;pecie ip&longs;ius laminæ AC habet ad aquæ grauitatem. quia x hydro&longs;taticis moles aquæ æqua

lis &longs;patio GKBC æquè ponde­rat, ac lamina AC vnà cum ae­re GKAD (qui ob in&longs;en&longs;ibilem eius grauitatem negligi pote&longs;t) & pondus ab&longs;olutum laminæ AC ad ab&longs;olutam gra­uitatem aquæ eiu&longs;dem molis AC eamdem proportio­nem habet quam grauitas &longs;pecifica laminæ AC ad &longs;pecificam grauitatem aquæ, ergo grauitas laminæ ad aquæ grauitatem in &longs;pecie eamdem proportione&mtail; habet, quam pondus molis aquæ GKBC ab&longs;olutæ ad pondus molis aquæ AC, &longs;eù proportionem, quam ha­bet moles GKBC ad molem AC: e&longs;t verò pri&longs;ma RB CS minus &longs;olido inæqualium ba&longs;ium GKBC, ergo pri&longs;ma RBCS ad AC &longs;eù altitudo SC ad DC minorem proportionem habet, quàm laminæ AC grauitas in­&longs;pecie ad aquæ grauitatem. Itaque vulgata propo&longs;i­tio vera e&longs;&longs;et &longs;i &longs;patium cauitatis ab aere repletum haberet parietes AK, & DG directos, & perpen­diculares ad horizontem, &longs;cilicèt &longs;i ba&longs;is KG æqua­lis foret ip&longs;i AD; at quia ob curuitatem in&longs;ignem &longs;u­perficierum AK & DG, &longs;emper altitudo CS ad cra&longs;&longs;i­tiem laminæ DC minorem proportionem habet quam grauitas &longs;pecifica &longs;olidi AC ad eam, quam habet aqua.

& huiu&longs;modi proportio &longs;emper magis, ac magis im­minuitur, quò magis con&longs;tringitur ba&longs;is laminæ AC, itaut po&longs;ito quòd lamina aurea AC &longs;it vige&longs;ies graui­or &longs;pecie ip&longs;a aqua, pote&longs;t adeò imminui ba&longs;is eius AD vt altitudo arginum SD minor &longs;it quàm CD, cùm tamen debuerat e&longs;&longs;e SD ad DC vt 19 ad 1, propterea quod anuli triangularis SDG cra&longs;&longs;ities SG &longs;emper e&longs;t eiu&longs;dem men&longs;uræ pote&longs;t adeo con&longs;tringi circulus ba&longs;is AD interceptus vt valdè excedat prædictu&mtail; circulum, & cylindrum interceptum, vt facilè o&longs;tendi po&longs;&longs;et.

Cap. 9. de corpu&longs;culo­rum innatan­tium mutuo amplexu at­que fuga.

PROP. CCI.

Pondus molis aquæ æqualis portioni innatantis corporis infra aquæ libellam demer&longs;i non e&longs;t præcisè æquale ponderi to­tius inn at antis corporis.

SEcundo loco operæpretium erit innuere quod ex prædictis montuo&longs;itatibus fluidi eleuatis, aut de­pre&longs;&longs;is miris modis alterantur propo&longs;itiones illæ, quæ in hydro&longs;taticis demon&longs;tratæ &longs;unt; quando enim effi­ciuntur argines eleuati; tunc moles aquæ æqualis &longs;pa­tio corporis innatantis infra aquæ libellam demer&longs;i non e&longs;t eiu&longs;dem ponderis, ac e&longs;t corpus ip&longs;um innatans, quando quidem argines illi aquei vndique eleuati gra­ues quoque &longs;unt, & &longs;u&longs;penduntur ob adhærentiam, & connexionem cum a&longs;peritatibus externis eiu&longs;dem in­natantis corporis, at quia à prædicto pondere adiun­cto arginum grauius ab&longs;olutè redditur corpus præ di-ctum, & ideò multò magis deprimitur, quàm &longs;i à præ­dicto anulo montuo&longs;o aquæ non grauaretur. huiu&longs;mo­di verò exce&longs;&longs;us in&longs;ignis e&longs;&longs;e pote&longs;t, &longs;i enim tabul&atail; grandis metallica &longs;upra hydrargy rum innataret, mon­tuo&longs;itates illæ adhærentes nedùm pondus vnciarum, &longs;ed etiam aliquarum librarum excederet. Et hìc ani­maduertendum e&longs;t, quòd men&longs;ura demer&longs;ionis &longs;umi non debet ab illis &longs;upremis terminis, quos attingunt argines aquei eleuati, cùm hoc &longs;it manife&longs;tè fal&longs;um.