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New Special Instructions
| author | Klaus Thoden <kthoden@mpiwg-berlin.mpg.de> |
|---|---|
| date | Wed, 30 Jul 2014 15:58:21 +0200 |
| parents | 22d6a63640c6 |
| children |
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<?xml version="1.0"?> <!DOCTYPE archimedes SYSTEM "../dtd/archimedes.dtd"> <archimedes xmlns:xlink="http://www.w3.org/1999/xlink"> <info> <author>Boyle, Robert</author> <title>New experiments physico-mechanicall, touching the spring of the air and its effects</title> <date>1660</date> <place>Oxford</place> <translator/> <lang>en</lang> <cvs_file>boyle_exper_013_en_1660.xml</cvs_file> <cvs_version/> <locator>013.xml</locator> </info> <text> <front> </front> <body> <chap> <pb xlink:href="013/01/001.jpg"/><p type="main"> <s><emph type="center"/>NEW <lb/><emph type="italics"/>EXPERIMENTS <lb/>Phy&longs;ico-Mechanicall <lb/>Touching the Air.<emph.end type="italics"/><emph.end type="center"/></s></p><pb xlink:href="013/01/002.jpg"/><pb xlink:href="013/01/003.jpg"/><p type="main"> <s><emph type="center"/>NEW <lb/>EXPERIMENTS <lb/><emph type="italics"/>Phy&longs;ico-Mechanicall,<emph.end type="italics"/><lb/>Touching<emph.end type="center"/></s></p><p type="main"> <s><emph type="center"/>The SPRING of the AIR, <lb/>and its EFFECTS, <lb/>(Made, for the mo&longs;t part, in a New <lb/><emph type="italics"/>PNEuMATICAL ENGINE<emph.end type="italics"/>)<emph.end type="center"/></s></p><p type="main"> <s><emph type="center"/>Written by way of LETTER<emph.end type="center"/></s></p><p type="main"> <s><emph type="center"/>To the Right Honorable <emph type="italics"/>Charles<emph.end type="italics"/><lb/>Lord Vicount of <emph type="italics"/>Dungarvan,<emph.end type="italics"/><lb/>Elde&longs;t Son to the EARL of <emph type="italics"/>CORKE.<emph.end type="italics"/><emph.end type="center"/></s></p><p type="main"> <s><emph type="center"/>By the Honorable <emph type="italics"/>Robert Boyle<emph.end type="italics"/> <expan abbr="E&longs;q;">E&longs;que</expan><emph.end type="center"/></s></p><figure id="id.013.01.003.1.jpg" xlink:href="013/01/003/1.jpg"/><p type="main"> <s><emph type="center"/><emph type="italics"/>OXFORD:<emph.end type="italics"/><lb/>Printed by <emph type="italics"/>H: Hall,<emph.end type="italics"/> Printer to the Univer&longs;ity, <lb/>for <emph type="italics"/>The: Robin&longs;on.<emph.end type="italics"/> 1660.<emph.end type="center"/></s></p><pb xlink:href="013/01/004.jpg"/><pb xlink:href="013/01/005.jpg"/><figure id="id.013.01.005.1.jpg" xlink:href="013/01/005/1.jpg"/><p type="main"> <s><emph type="center"/>To the Reader.<emph.end type="center"/></s></p><p type="main"> <s><emph type="italics"/>ALthough the following Trea­<lb/>ti&longs;e being far more prolix <lb/>then becomes a Letter, and <lb/>then I at fir&longs;t intended it; I <lb/>am very unwilling to en­<lb/>crea&longs;e the already exce&longs;sive bulk of the <lb/>Book by a Preface, yet there are &longs;ome par­<lb/>ticulars that I think my &longs;elf oblig'd to take <lb/>notice of to the Reader, as things, that will <lb/>either concern him to know, or me to have <lb/>known.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>In the fir&longs;t place then: If it be demand­<lb/>ed why I publi&longs;h to the World a Letter, which <lb/>by its Stile and diver&longs;e Pa&longs;&longs;ages, appears <lb/>to have been written as well For, as To a <lb/>particular Per&longs;on; I have chiefly the&longs;e two <lb/>things to an&longs;wer: The one, That the Ex­<lb/>periments therein related, having been ma­<lb/>ny of them try'd in the pre&longs;ence of Ingeni­<lb/>ous Men; and by that means having made<emph.end type="italics"/><pb xlink:href="013/01/006.jpg"/><emph type="italics"/>&longs;ome noi&longs;e among the<emph.end type="italics"/> Virtuo&longs;i (<emph type="italics"/>in&longs;omuch <lb/>that &longs;ome of them have been &longs;ent into Fo­<lb/>reign Countries, where they have had the <lb/>luck not to be de&longs;pi&longs;'d) I could not without <lb/>quite tyring more then one<emph.end type="italics"/> Amanuen&longs;is, <emph type="italics"/>give <lb/>out half as many Copies of them as were &longs;o <lb/>earne&longs;tly de&longs;ired, that I could not civilly <lb/>refu&longs;e them. </s> <s>The other, That intelligent <lb/>Per&longs;ons in matters of this kinde per&longs;waded <lb/>me, that the publication of what I had ob­<lb/>&longs;erv'd touching the Nature of the Air, <lb/>would not be u&longs;ele&longs;s to the World; and that <lb/>in an Age &longs;o taken with Novelties as is ours, <lb/>the&longs;e new Experiments would be grateful to <lb/>the Lovers of free and real Learning: So <lb/>that I might at once comply with my grand <lb/>De&longs;ign of promoting Experimental and <lb/>U&longs;eful Philo&longs;ophy, and obtain the great &longs;a­<lb/>tisfaction of giving &longs;ome to ingenious Men; <lb/>the hope of which, is, I confe&longs;s, a tempta­<lb/>tion that I cannot ca&longs;ily re&longs;i&longs;t.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>Of my being &longs;omewhat prolix in many <lb/>of my Experiments, I have the&longs;e Rea&longs;ons <lb/>to render, That &longs;ome of them being altoge­<lb/>ther new, &longs;eem'd to need the being circum­<lb/>&longs;tantially related, to keep the Reader from <lb/>di&longs;tru&longs;ting them: That divers Circum­<lb/>&longs;tances I did here and there &longs;et down for fear <lb/>of forgetting them, when I may hereafter<emph.end type="italics"/><pb xlink:href="013/01/007.jpg"/><emph type="italics"/>have occa&longs;ion to make u&longs;e of them in my o­<lb/>ther Writings: That in divers ca&longs;es I <lb/>thought it nece&longs;&longs;ary to deliver things cir­<lb/>cum&longs;tantially, that the Per&longs;on I addre&longs;&longs;ed <lb/>them to, might without mi&longs;take, and with <lb/>as little trouble as is po&longs;sible, be able to re­<lb/>peat &longs;uch unu&longs;ual Experiments: and that <lb/>after I con&longs;ented to let my Ob&longs;ervations be <lb/>made publick, the mo&longs;t ordinary Rea&longs;on of <lb/>my prolixity was, That fore&longs;eeing that &longs;uch <lb/>a trouble as I met with in making tho&longs;e try­<lb/>als carefully, and the great expence of time <lb/>that they nece&longs;&longs;arily require, (not to mention <lb/>the charges of making the Engine, and im­<lb/>ploying a man to manage it) will probably <lb/>keep mo&longs;t men from trying again the&longs;e Ex­<lb/>periments; I thought I might doe the gene­<lb/>rality of my Readers no unacceptable pe<gap/>ce <lb/>of &longs;ervice, by &longs;o punctually relating what <lb/>I carefully ob&longs;erv'd, that they may look up­<lb/>on the&longs;e Narratives as &longs;tanding Records in <lb/>our new Pneumaticks, and need not reite­<lb/>rate them&longs;elves an Experiment to have as <lb/>di&longs;tinct an Idea of it, as may &longs;uffice them <lb/>to ground their Reflections and Speculations <lb/>upon.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>And becau&longs;e &longs;ometimes 'tis the Di&longs;cour&longs;e <lb/>made upon the Experiment that makes it <lb/>appear prolix, I have commonly left a con-<emph.end type="italics"/><pb xlink:href="013/01/008.jpg"/><emph type="italics"/>&longs;picuous interval betwixt &longs;uch Di&longs;cour&longs;es, <lb/>and the Experiments whereunto they belong, <lb/>or are annexed; that they who de&longs;ire onely <lb/>the Hi&longs;torical part of the account we give <lb/>of our Engine, may read the Narra­<lb/>tives, without being put to the trouble <lb/>of reading the Reflections too: Which I <lb/>here take notice of, for the &longs;ake of tho&longs;e <lb/>that are well ver&longs;'d in the New Philo&longs;ophy, <lb/>and in the Mathematicks; that &longs;uch <lb/>may skip what was de&longs;ign'd, but for &longs;uch <lb/>Per&longs;ons as may be le&longs;s acquainted even then <lb/>I, with matters of this nature (&longs;carce &longs;o <lb/>much as mention'd by any Writer in our <lb/>Language) and not for them from whom <lb/>I &longs;hall be much more forward to learn, then <lb/>to pretend to teach them. </s> <s>Of my being <lb/>wont to &longs;peak rather doubtfully, or he&longs;itant­<lb/>ly, then re&longs;olvedly, concerning matters <lb/>wherein I apprehend &longs;ome difficulty, I have <lb/>in another Treati&longs;e (which may, through <lb/>Gods A&longs;si&longs;tance, come abroad ere long) <lb/>given a particular, and I hope a &longs;atisfacto­<lb/>ry account: Wherefore I &longs;hall now defend <lb/>my Practice but by the Ob&longs;ervation of<emph.end type="italics"/> Ari­<lb/>&longs;totle, <emph type="italics"/>who &longs;omewhere notes, That to &longs;eem <lb/>to know all things certainly, and to &longs;peak <lb/>po&longs;itively of them, is a trick of bold and <lb/>yong Fellows: Whereas tho&longs;e that are in-<emph.end type="italics"/><pb xlink:href="013/01/009.jpg"/><emph type="italics"/>deed intelligent and con&longs;iderate, are wont to <lb/>imploy more wary and diffident Expre&longs;si­<lb/>ons, or (as he &longs;peaks)<emph.end type="italics"/> <foreign lang="greek"><gap/>sife/ad<gap/> a)ei\ to\ <gap/>s, <lb/><gap/> to\ ta\xa. </foreign></s></p><p type="main"> <s><emph type="italics"/>There are divers Reflections, and other <lb/>Pa&longs;&longs;ages in the following Epi&longs;tle, and even <lb/>&longs;ome Experiments (occa&longs;ionally mention'd) <lb/>which may &longs;eem either impertinent or &longs;u­<lb/>perfluous, but are not &longs;o: Being purpo&longs;ely <lb/>written, either to evince &longs;ome truth oppo&longs;'d, <lb/>or di&longs;prove &longs;ome erroneous conceit main­<lb/>tain'd, by &longs;ome eminent New Philo&longs;opher, <lb/>or by &longs;ome other Ingenious Men, who, I <lb/>pre&longs;um'd, would ea&longs;ily forgive me the ha­<lb/>ving on &longs;uch occa&longs;ions purpo&longs;ely omitted <lb/>their Names; though an inqui&longs;itive Per&longs;on <lb/>will probably di&longs;cover divers of them, by <lb/>the mention of the Opinions di&longs;prov'd in <lb/>the Experiments I am excu&longs;ing.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>Ever &longs;ince I di&longs;cern'd the u&longs;efulne&longs;s <lb/>of &longs;peculative Geometry to Natural Phi­<lb/>lo&longs;ophy, the unhappy Di&longs;tempers of my Eyes, <lb/>have &longs;o far kept me from being much con­<lb/>ver&longs;ant in it, that I fear I &longs;hall need the par­<lb/>doz of my Mathematical Readers, for &longs;ome <lb/>Pa&longs;&longs;ages, which if I had been deeply skill'd <lb/>in Geometry, I &longs;hould have treated more ac­<lb/>curately.<emph.end type="italics"/></s></p><pb xlink:href="013/01/010.jpg"/><p type="main"> <s><emph type="italics"/>And indeed, having, for Rea&longs;ons el&longs;e­<lb/>where deduc'd, purpo&longs;ely kept my &longs;elf a <lb/>&longs;tranger to mo&longs;t of the new<emph.end type="italics"/> Hypothe&longs;es <emph type="italics"/>in <lb/>Philo&longs;ophy, I am &longs;en&longs;ible enough that the <lb/>Engine I treat of has prevail'd with me to <lb/>write of &longs;ome &longs;ubjects which are &longs;ufficient­<lb/>ly remote from tho&longs;e I have been mo&longs;t con­<lb/>ver&longs;ant in. </s> <s>And having been reduc'd to <lb/>write the greate&longs;t part of the en&longs;uing Letter <lb/>at a di&longs;tance, not onely from my Library, <lb/>but from my own Manu&longs;cripts, I cannot <lb/>but fear that my Di&longs;cour&longs;es do not onely <lb/>want many choice things wherewith the <lb/>Learned Writings of others might have en­<lb/>riched or imbelli&longs;hed them: But that partly <lb/>for this Rea&longs;on, and partly for that touch'd <lb/>upon a little before, It is po&longs;sible I may <lb/>have mention'd &longs;ome Notions already pub­<lb/>li&longs;h'd by others, without taking notice of the <lb/>Authors, not out of any de&longs;ign to defraud <lb/>de&longs;erving Men, but for want of knowing <lb/>&longs;uch particulars to have been already pub­<lb/>li&longs;h'd by them: E&longs;pecially the Experiments <lb/>of our Engine being them&longs;elves &longs;ufficient <lb/>to hint &longs;uch Notions as we build upon <lb/>them.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>The order of the Experiments every <lb/>Reader may alter, as &longs;uits be&longs;t with his own <lb/>De&longs;ign in peru&longs;ing them; For not onely all<emph.end type="italics"/><pb xlink:href="013/01/011.jpg"/><emph type="italics"/>tho&longs;e betwixt whom there is an Affinity in <lb/>Nature (by belonging to one &longs;ubject) are not <lb/>always plac'd one by another, but they are <lb/>not &longs;till &longs;et down &longs;o much as in the order <lb/>wherein they were made; but mo&longs;t common­<lb/>ly in that ca&longs;ual one wherein my occa&longs;ions in­<lb/>duc'd me to di&longs;patch them to the Pre&longs;s. </s> <s>And, <lb/>which is wor&longs;e, I did u&longs;ually &longs;end quite a­<lb/>way the former Experiments, before the <lb/>later were written, or perhaps &longs;o much as <lb/>made: Whereby I lo&longs;t the advantage of cor­<lb/>recting and &longs;upplying the Imperfections of <lb/>what I had formerly written, by the light of <lb/>my &longs;ub&longs;equent Tryals and Di&longs;coveries.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>Be&longs;ides all this, the di&longs;temper in my eyes <lb/>forbidding me not onely to write my &longs;elf &longs;o <lb/>much as one Experiment, but even to read <lb/>over my &longs;elf what I dictated to others. </s> <s>I can­<lb/>not but fear, that be&longs;ides the Authors mi&longs;takes, <lb/>this Edition may be blemi&longs;h'd by many, that <lb/>may be properly imputed to a very unskil­<lb/>ful Writer (whom I was often times by ha&longs;te <lb/>reduc'd again&longs;t my cu&longs;tom to imploy) and <lb/>may have e&longs;caped the Diligence of that <lb/>Learned Friend, that does me the favor to <lb/>over-&longs;ee the Pre&longs;s; e&longs;pecially there being <lb/>the di&longs;tance of two days Fourney betwixt it <lb/>and me.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>I need not perhaps repre&longs;ent to the equi-<emph.end type="italics"/><pb xlink:href="013/01/012.jpg"/><emph type="italics"/>table Reader, how much the &longs;trange Confu­<lb/>&longs;ions of this unhappy Nation, in the mid&longs;t <lb/>of which I have made and written the&longs;e <lb/>Experiments, are apt to di&longs;turb that calm­<lb/>ne&longs;s of Minde, and undi&longs;tractednc&longs;s of <lb/>Thoughts, that are wont to be requi&longs;ite to <lb/>Happy Speculations. </s> <s>But I pre&longs;ume, <lb/>that by all the&longs;e things put together, he <lb/>will readily perceive, That I have been <lb/>&longs;o far from following the Poets prudent <lb/>Coun&longs;el touching the &longs;low Publication of <lb/>Books de&longs;ign'd to purcha&longs;e credit by,<emph.end type="italics"/></s></p><p type="main"> <s>—— Nonumque prematur in Annum </s></p><p type="main"> <s><emph type="italics"/>that I &longs;uffer this Treati&longs;e to come abroad <lb/>into the World with a multitude of Di&longs;ad­<lb/>vantages.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>But if it be demanded, why then I did <lb/>not make it fitter for the Pre&longs;s before I &longs;ent <lb/>it thither? </s> <s>my An&longs;wer mu&longs;t be, That not <lb/>at fir&longs;t imagining that this &longs;ort of Experi­<lb/>ments would prove any thing near &longs;o trouble­<lb/>&longs;ome, either to make, or to Record, as I <lb/>afterwards found them, I did, to engage <lb/>the Printer to di&longs;patch, promi&longs;e him to &longs;end <lb/>him the whole Epi&longs;tle in a very &longs;hort time: <lb/>So that although now and then the occa&longs;ional <lb/>vacations of the Pre&longs;s, by rea&longs;on of Fe&longs;ti-<emph.end type="italics"/><pb xlink:href="013/01/013.jpg"/><emph type="italics"/>vals, or the ab&longs;ence of the Corrector, gave <lb/>me the lei&longs;ure to ex&longs;paciate upon &longs;ome &longs;ub­<lb/>ject; yet being oftentimes call'd upon to di&longs;­<lb/>patch the Papers to the Pre&longs;s, my promi&longs;e, <lb/>and many unexpected Avocations, obliged <lb/>me to a ha&longs;te, which, though it have detract­<lb/>ed nothing from the Faithfulne&longs;s of the <lb/>Hi&longs;torical part of our Book, has (I fear) <lb/>been di&longs;advantageous enough to all the re&longs;t. <lb/></s> <s>And I made the le&longs;s &longs;cruple to let the fol­<lb/>lowing Papers pa&longs;s out of my hands, with <lb/>all their Imperfections; becau&longs;e, as the <lb/>publick Affairs, and my own, were then <lb/>circum&longs;tanc'd, I knew not when (if at all) <lb/>I &longs;hould be again in a condition to pro&longs;ecute <lb/>Experiments of this kinde; e&longs;pecially, <lb/>&longs;ince (to omit my being almo&longs;t weary of be­<lb/>ing, as it were, confin'd to one &longs;ort of Ex­<lb/>periments) I am pre-ingag'd (if it plea&longs;e <lb/>God to vouch&longs;afe me Life and Health) to <lb/>imploy my fir&longs;t lei&longs;ure in the publication of <lb/>&longs;ome other Phy&longs;iological Papers, which I <lb/>thought 'twould make me much the &longs;itter to <lb/>take in hand, if I fir&longs;t di&longs;patch'd all that <lb/>I had at this time to write touching our <lb/>Engine.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>I have this further to adde, by way <lb/>of Excu&longs;e, That as it has been my de&longs;ign <lb/>in publi&longs;hing the&longs;e Experiments to gratifie<emph.end type="italics"/><pb xlink:href="013/01/014.jpg"/><emph type="italics"/>Ingenious men; &longs;o, if I have not been <lb/>much flattered, I may hope that the vari­<lb/>ous hints to be met with in the following <lb/>Letter, will (at lea&longs;t) &longs;omewhat awaken <lb/>mens thoughts, & excite them to new &longs;pecula­<lb/>tions (&longs;uch as perhaps even inqui&longs;itive men <lb/>would &longs;carce el&longs;e light upon) and I need not <lb/>de&longs;pair, that even the examination of &longs;uch <lb/>new Su&longs;picions and Enquiries will hence al­<lb/>&longs;o, at lea&longs;t Occa&longs;ionally be facilitated: I <lb/>&longs;aid Occa&longs;ionally, becau&longs;e it being, as 'tis <lb/>proverbially &longs;aid,<emph.end type="italics"/> Facile Inventis addere. <lb/><emph type="italics"/>It &longs;eems not irrational to expect, that our <lb/>Engine it &longs;elf, and divers of our Experi­<lb/>ments, will be much promoted by the Indu­<lb/>&longs;try of Inventive and Mathematical Wits, <lb/>who&longs;e contrivances may ea&longs;ily either correct <lb/>or &longs;upply, and con&longs;equently &longs;urpa&longs;s many of <lb/>tho&longs;e we have made u&longs;e of. </s> <s>And, particu­<lb/>larly, if Men by skill and patience can ar­<lb/>rive both to evacuate &longs;uch Receivers as <lb/>ours, till there be no more Air left in them, <lb/>then there &longs;eems to have remain'd in the <lb/>Gla&longs;&longs;es made u&longs;e of about the Magdebur­<lb/>gick Experiment (hereafter to be mention­<lb/>ed) and to keep out the Air for a competent <lb/>while, the U&longs;efulne&longs;s and Di&longs;coveries of our <lb/>Engine, will not be a little advanc'd. </s> <s>And <lb/>perhaps that may belong to it, which I re-<emph.end type="italics"/><pb xlink:href="013/01/015.jpg"/><emph type="italics"/>member<emph.end type="italics"/> Seneca <emph type="italics"/>&longs;peaks of Nature,<emph.end type="italics"/> Initia­<lb/>tos (<emph type="italics"/>&longs;ays be<emph.end type="italics"/>) nos credimus, in Ve&longs;tibulo <lb/>ejus hæremus: <emph type="italics"/>For being now in a place <lb/>where we are not quite de&longs;titute of moderate­<lb/>ly skilful Artificers, we have, &longs;ince the <lb/>Conclu&longs;ion of the following Letter, made <lb/>&longs;ome Additions to our Engine, by who&longs;e help <lb/>we finde (upon &longs;ome new tryals) that we <lb/>may be able, without much of new trouble, <lb/>to keep the ambient Air out of the exhau­<lb/>&longs;ted Receiver for a whole day; and perhaps <lb/>we &longs;hould be able to keep it out much longer, <lb/>if before we &longs;hall have di&longs;patch'd &longs;ome ur­<lb/>gent Affairs, and publi&longs;h'd &longs;ome Papers for <lb/>which a kinde of Promi&longs;e is thought to make <lb/>us Debtors to the Pre&longs;s, we could be at lei­<lb/>&longs;ure to pro&longs;ecute &longs;uch Experiments, as may <lb/>po&longs;sibly afford a Supplement to the follow­<lb/>ing Treati&longs;e, from which I &longs;hall now no lon­<lb/>ger detain the Reader.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>I know<emph.end type="italics"/></s></p><pb xlink:href="013/01/016.jpg"/><pb xlink:href="013/01/017.jpg"/><figure id="id.013.01.017.1.jpg" xlink:href="013/01/017/1.jpg"/><p type="main"> <s>Friendly Reader, </s></p><p type="main"> <s><emph type="italics"/>I Know all Per&longs;ons <lb/>that have a publick <lb/>Spirit for the Ad­<lb/>vancement of Lear­<lb/>ning, will think much that this <lb/>piece came not out in a Lan­<lb/>guage of more general U&longs;e, <lb/>then this you &longs;ee it now attir'd <lb/>in; e&longs;pecially &longs;ince the Excel­<lb/>lent Noble Per&longs;on, who is the <lb/>Author, is known to be well a­<lb/>ble him&longs;elf (being almo&longs;t uni­<lb/>ver&longs;ally a Lingui&longs;t) to have gi­<lb/>ven it either the Old Latin, or<emph.end type="italics"/><pb xlink:href="013/01/018.jpg"/><emph type="italics"/>the newer French Dre&longs;s.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>But if it be an Honor to a <lb/>Language to be preferr'd, and <lb/>this Honor breeds &longs;ometimes an <lb/>Emulation, as anciently it did <lb/>between the<emph.end type="italics"/> Greeks <emph type="italics"/>and<emph.end type="italics"/> Ro­<lb/>mans, <emph type="italics"/>it cannot be thought <lb/>unhand&longs;ome for an Engli&longs;h <lb/>Nobleman to have preferr'd <lb/>his own: And it may be a &longs;uf­<lb/>ficient Rea&longs;on for the Gentry <lb/>of Forein Parts to learn our <lb/>Speech, or keep Interpreters, <lb/>that they are &longs;ure to have for <lb/>their requital, from many of <lb/>our Engli&longs;h Writers (as here <lb/>from this piece) much curiou&longs;ly <lb/>ingenious, and profitable Lear­<lb/>ning.<emph.end type="italics"/></s></p><pb xlink:href="013/01/019.jpg"/><p type="main"> <s><emph type="italics"/>But as to this particular (give <lb/>me leave to u&longs;e Words from a <lb/>Story)<emph.end type="italics"/> Since the Mountain <lb/>cannot come to <emph type="italics"/>Mahomet, <lb/>Mahomet<emph.end type="italics"/> will go to the <lb/>Mountain<emph type="italics"/>: I mean thus; <lb/>Becau&longs;e many witty Men, Per­<lb/>&longs;ons of Honor and E&longs;tate e&longs;pe­<lb/>cially, may be &longs;uppo&longs;'d to be a­<lb/>ble to make a better account, by <lb/>employing their Studies and <lb/>Time on Matter then Words, <lb/>and &longs;o are ju&longs;tly impeded from <lb/>learning Languages; And be­<lb/>cau&longs;e (as I may judge) the no­<lb/>ble Author is willing to oblige all <lb/>Men, He has already provi­<lb/>ded, that this piece &longs;hall &longs;hort­<lb/>ly be done into Latine, that &longs;o<emph.end type="italics"/><pb xlink:href="013/01/020.jpg"/><emph type="italics"/>it may come home to divers wor­<lb/>thy Per&longs;ons in its Stream, who <lb/>cannot travel to finde it out in <lb/>its fir&longs;t Origine.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>Having therefore leave &longs;o <lb/>to do, I cannot forbear to give <lb/>the World the Adverti&longs;ement <lb/>of this Latine Edition, le&longs;t <lb/>&longs;ome skilful Arti&longs;t &longs;hould take <lb/>needle&longs;s pains about a Work, <lb/>which will, ere long (by Gods <lb/>furtherance) be done to his <lb/>Hands; For &longs;uch unprofitable <lb/>expences of Study have too fre­<lb/>quently happened, and too much <lb/>to the di&longs;advantage of Learn­<lb/>ing, for want of a &longs;ufficient <lb/>Corre&longs;pondence and Intercour&longs;e <lb/>between &longs;uch as are exerci&longs;ed<emph.end type="italics"/><pb xlink:href="013/01/021.jpg"/><emph type="italics"/>in the Mines of Wi&longs;dome.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>This is all the trouble I &longs;hall <lb/>at pre&longs;ent give you: Nor &longs;hall I <lb/>need minde thee, if you have a <lb/>true gu&longs;t for the Book you read, <lb/>to have an honor and thankful <lb/>regard to the Per&longs;on that has <lb/>favor'd us with the Communi­<lb/>cation of the&longs;e his Tryals, & is <lb/>manife&longs;tly &longs;o great a Patron <lb/>and Friend to Experimental <lb/>Learning, and all true Wi&longs;dom; <lb/>for &longs;hould you fail in this, you <lb/>might de&longs;ervedly be depriv'd of <lb/>&longs;ome other Ob&longs;ervations on the <lb/>&longs;ame &longs;ubject, which the Au­<lb/>thor, I heare, has made &longs;ince the <lb/>fini&longs;hing of this Treati&longs;e.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>I de&longs;ire to be excu&longs;ed that I<emph.end type="italics"/><pb xlink:href="013/01/022.jpg"/><emph type="italics"/>not make Excu&longs;es for the &longs;low­<lb/>ne&longs;s of the Publication, hoping <lb/>that the long expectation you <lb/>have had of it, will enhance, and <lb/>not dimini&longs;h your delight in the <lb/>enjoyment of a piece like to be, <lb/>among&longs;t the &longs;tudents in accurate <lb/>Philo&longs;ophy, of &longs;o generall accep­<lb/>tance. </s> <s>Farewel.<emph.end type="italics"/></s></p><p type="main"> <s>R: Sh. <lb/><figure id="id.013.01.022.1.jpg" xlink:href="013/01/022/1.jpg"/></s></p><pb xlink:href="013/01/023.jpg"/><figure id="id.013.01.023.1.jpg" xlink:href="013/01/023/1.jpg"/><p type="main"> <s><emph type="center"/>A Summary of the chief Matters treated <lb/>of in this Epi&longs;tolical Di&longs;cour&longs;e.<emph.end type="center"/></s></p><p type="main"> <s><emph type="italics"/>THe<emph.end type="italics"/> Proæmium, <emph type="italics"/>wherein is &longs;et down the <lb/>occa&longs;ion of this Di&longs;cour&longs;e,<emph.end type="italics"/> 1. <emph type="italics"/>The mo­<lb/>tives that induc'd the Author thereunto,<emph.end type="italics"/> 2 &c. <lb/><emph type="italics"/>The hints he received,<emph.end type="italics"/> 5. <emph type="italics"/>The things where­<lb/>in this Engine excels any that have yet been <lb/>made u&longs;e of,<emph.end type="italics"/> 6 &c. <emph type="italics"/>The de&longs;cription of the <lb/>Engine and its parts,<emph.end type="italics"/> 8 &c. <emph type="italics"/>The way of pre­<lb/>paring and u&longs;ing it,<emph.end type="italics"/> 15 &c. <emph type="italics"/>The divi&longs;ion of <lb/>the Experiments tryable thereby into two <lb/>&longs;orts, and the difficulty of excluding the <lb/>Air.<emph.end type="italics"/> 18 &c. </s></p><p type="main"> <s><emph type="italics"/>The fir&longs;t Experiment, touching the man­<lb/>ner of pumping out the Air, and by what de­<lb/>grees the Receiver is emptyed,<emph.end type="italics"/> 20, &c. <emph type="italics"/>A di­<lb/>gre&longs;sion touching the Spring or Ela&longs;tical <lb/>power of the Air, with an attempt for a Me­<lb/>chanical Explication thereof, nece&longs;&longs;ary to be <lb/>premi&longs;'d for the explanation of the<emph.end type="italics"/> Phæno­<lb/>mena, <emph type="italics"/>exhibited in this and the &longs;ub&longs;equent <lb/>Experiments.<emph.end type="italics"/> 22 &c. </s></p><p type="main"> <s><emph type="italics"/>The &longs;econd Experiment, touching the pre&longs;­<lb/>&longs;ure of the Air again&longs;t the &longs;ides of the Bodies <lb/>it invirons,<emph.end type="italics"/> 37 &c. <emph type="italics"/>with a digre&longs;sive Ex­<lb/>plication of the pre&longs;&longs;ure of the Air included <lb/>within an ambient Body.<emph.end type="italics"/> 39 &c. </s></p><pb xlink:href="013/01/024.jpg"/><p type="main"> <s><emph type="italics"/>The third Experiment, touching the <lb/>force requi&longs;ite to draw down the Sucker,<emph.end type="italics"/> 42 <lb/>&c. <emph type="italics"/>The Opinion of an eminent Modern <lb/>Naturali&longs;t examin'd.<emph.end type="italics"/> 44 &c. </s></p><p type="main"> <s><emph type="italics"/>The fourth Experiment, touching the <lb/>&longs;welling of a Bladder; with the degrees by <lb/>which it increa&longs;es,<emph.end type="italics"/> 45 &c. <emph type="italics"/>Another Opini­<lb/>on of a Learned Author examin'd.<emph.end type="italics"/> 48 &c. </s></p><p type="main"> <s><emph type="italics"/>The fifth Experiment, touching the break­<lb/>ing of a Bladder in the Receiver,<emph.end type="italics"/> 49 &c. <lb/><emph type="italics"/>And of another by heat.<emph.end type="italics"/> 52 </s></p><p type="main"> <s><emph type="italics"/>The &longs;ixth Experiment, of divers ways by <lb/>which the ela&longs;tical expan&longs;ion of the Air <lb/>was mea&longs;ur'd.<emph.end type="italics"/> 52 &c </s></p><p type="main"> <s><emph type="italics"/>The &longs;eventh Experiment, touching what <lb/>Figure does be&longs;t re&longs;i&longs;t the pre&longs;&longs;ure of the Air.<emph.end type="italics"/> 62 &c. </s></p><p type="main"> <s><emph type="italics"/>The eighth Experiment, tending to a fur­<lb/>ther Demon&longs;tration of the former, from the <lb/>breaking of gla&longs;s a Helmet inward.<emph.end type="italics"/> 64 &c. </s></p><p type="main"> <s><emph type="italics"/>The ninth Experiment, contains a fur­<lb/>ther confirmation from the breaking of a <lb/>Gla&longs;s outward,<emph.end type="italics"/> 66 &c. <emph type="italics"/>with an Experiment to <lb/>prove, that the&longs;e<emph.end type="italics"/> Phænomena <emph type="italics"/>proceed not <lb/>from an invincible<emph.end type="italics"/> Fuga vacui 69. <emph type="italics"/>A de­<lb/>&longs;cription of other &longs;mall Receivers, and their <lb/>Conveniencies,<emph.end type="italics"/> 70 &c. <emph type="italics"/>A Receipt for the <lb/>making of a Compo&longs;ition to Cement crackt <lb/>Gla&longs;&longs;es.<emph.end type="italics"/> 73 </s></p><pb xlink:href="013/01/025.jpg"/><p type="main"> <s><emph type="italics"/>The tenth Experiment, touching the fla­<lb/>ming of Candles inclo&longs;ed in the Receiver.<emph.end type="italics"/> 74 &c. </s></p><p type="main"> <s><emph type="italics"/>The eleventh Expertment, touching the <lb/>burning of Coals,<emph.end type="italics"/> 78. <emph type="italics"/>And the la&longs;ting of <lb/>the excande&longs;cence of an included piece of I­<lb/>ron.<emph.end type="italics"/> 80. </s></p><p type="main"> <s><emph type="italics"/>The twelfth Experiment concerning the <lb/>burning of Match.<emph.end type="italics"/> 82 </s></p><p type="main"> <s><emph type="italics"/>The thirteenth Experiment, concerning <lb/>the further pro&longs;ecution of the preceding, <lb/>tending to prove the extinction of the Fire <lb/>in the former Experiments, not to have <lb/>proceeded from the pre&longs;&longs;ure of the Fire by the <lb/>Fumes,<emph.end type="italics"/> 84. <emph type="italics"/>Some remarkable Circum&longs;tan­<lb/>ces of it,<emph.end type="italics"/> 86. <emph type="italics"/>The Experiment of Match <lb/>try'd in a &longs;mall Receiver.<emph.end type="italics"/> 87 </s></p><p type="main"> <s><emph type="italics"/>The fourteenth Experiment, touching the <lb/>&longs;triking Fire, and kindling of Powder with <lb/>the Lock of a Pi&longs;tol in the evacuated Recei­<lb/>ver.<emph.end type="italics"/> 88 &c. </s></p><p type="main"> <s><emph type="italics"/>The fifteenth Experiment, touching the <lb/>un&longs;ucce&longs;sfulne&longs;s of kindling included Bo­<lb/>dies with a burning Gla&longs;s, and the Au­<lb/>thors intention to pro&longs;ecute it further.<emph.end type="italics"/> 102 </s></p><p type="main"> <s><emph type="italics"/>The &longs;ixteenth Experiment, concerning the <lb/>operation of the Load&longs;tone.<emph.end type="italics"/> 105, &c. </s></p><pb xlink:href="013/01/026.jpg"/><p type="main"> <s><emph type="italics"/>The &longs;eventeenth Experiment, touching the <lb/>gradual de&longs;cent of the Quick-&longs;ilver in the <lb/>Torricellian Experiment,<emph.end type="italics"/> 106 &c. <emph type="italics"/>Some <lb/>ob&longs;ervable Circum&longs;tances concerning it,<emph.end type="italics"/><lb/>112 &c. <emph type="italics"/>The &longs;ame Experiment try'd in <lb/>one of the &longs;mall Receivers,<emph.end type="italics"/> 115. <emph type="italics"/>How <lb/>this Experiment may be made u&longs;e of to know <lb/>the &longs;trength of the pre&longs;&longs;ure of the Air for <lb/>every degree of Rarefaction,<emph.end type="italics"/> 116 &c. <emph type="italics"/>The <lb/>tryal of the &longs;ame Experiment in a Tube not <lb/>two foot long,<emph.end type="italics"/> 118. <emph type="italics"/>The rai&longs;ing of the Mer­<lb/>curial Cylinder, by the forcing of more Air <lb/>into the Receiver,<emph.end type="italics"/> 119. <emph type="italics"/>Some Allegations <lb/>for and again&longs;t a<emph.end type="italics"/> Vacuum <emph type="italics"/>con&longs;ider'd,<emph.end type="italics"/> 120 <lb/>&c. <emph type="italics"/>Some Adverti&longs;ements concerning the <lb/>inconveniencies that may ari&longs;e from the di­<lb/>ver&longs;ity of mea&longs;ures made u&longs;e of for the defi­<lb/>ning the Altitute of the Mercurial Cylinder; <lb/>and from the neglect of little parcels of Air <lb/>apt to remain between the Mercury and the <lb/>concave &longs;urface of the Tube,<emph.end type="italics"/> 123 &c. <emph type="italics"/>Some <lb/>Expedients for the more exact filling the <lb/>Tube,<emph.end type="italics"/> 127. <emph type="italics"/>The height the Author once found <lb/>of the Mercurial Cylinder, according to En­<lb/>gli&longs;h mea&longs;ure.<emph.end type="italics"/> 128. </s></p><p type="main"> <s><emph type="italics"/>The eighteenth Experiment, containing <lb/>a new Ob&longs;ervation touching the variation <lb/>of the height of the Mercurial Cylinder in <lb/>the &longs;ame Tube, with an o&longs;&longs;er at the rea&longs;on<emph.end type="italics"/><pb xlink:href="013/01/027.jpg"/><emph type="italics"/>thereof.<emph.end type="italics"/> 129 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 19<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, touching the &longs;ub­<lb/>&longs;iding of a Cylinder of Water,<emph.end type="italics"/> 140 &c. <emph type="italics"/>The <lb/>&longs;ame try'd in a &longs;mall Receiver.<emph.end type="italics"/> 143 </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 20<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, touching the<emph.end type="italics"/> Ela­<lb/>ter <emph type="italics"/>of Water, with a digre&longs;sive Experiment <lb/>to the &longs;ame purpo&longs;e<emph.end type="italics"/> 144 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 21 <emph type="italics"/>Experiment, being a pro&longs;ecution <lb/>of the former Enquiry, by Experimenting <lb/>the Generation of Bubbles under Water, a <lb/>recital of &longs;ome notable Circum&longs;tances, with <lb/>&longs;ome ob&longs;ervable Corollary's deduc'd there­<lb/>from.<emph.end type="italics"/> 147 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 22<emph type="sup"/>d<emph.end type="sup"/> <emph type="italics"/>Experiment, tending to a deter­<lb/>mination of the Enquiry propo&longs;'d in the for­<lb/>mer Experiment, by proving the matter of <lb/>the&longs;e Bubbles from their permanency to be <lb/>Air: The Experiments try'd in the great <lb/>and &longs;mall Receivers, evincing the &longs;ame <lb/>thing,<emph.end type="italics"/> 155 &c. <emph type="italics"/>An Experiment wherein <lb/>there appear'd Bubbles in Quick-&longs;ilver,<emph.end type="italics"/><lb/>160. <emph type="italics"/>The Authors Inference,<emph.end type="italics"/> 162. <emph type="italics"/>A di­<lb/>gre&longs;sive Enquiry, whether or no Air may be <lb/>generated anew; with &longs;everal Hi&longs;tories and <lb/>Experiments, tending to the re&longs;olving and <lb/>clearing thereof.<emph.end type="italics"/> 162 &c <emph type="italics"/>The Authors ex­<lb/>cu&longs;e for &longs;o long a Digre&longs;sion.<emph.end type="italics"/> 181 </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 23<emph type="sup"/>d<emph.end type="sup"/> <emph type="italics"/>Experiment, containing a fur­<lb/>ther Enquiry touching Bubbles mad with<emph.end type="italics"/><pb xlink:href="013/01/028.jpg"/><emph type="italics"/>common and di&longs;till'd Water.<emph.end type="italics"/> 182 </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 24<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, wherein the inqui­<lb/>ry is pro&longs;ecuted with other Liquors, as with <lb/>Sallet Oyl, Oyl of Turpentine, a Solution of <lb/>Tartar, Spirit of Vinegar, Red-wine, Milk, <lb/>Hen's Eggs, Spirit of Urine, Spirit of <lb/>Wine and Water, Spirit of Wine.<emph.end type="italics"/> 187 &c. <lb/><emph type="italics"/>The wonderful expan&longs;ion of the Spirit of <lb/>Wine.<emph.end type="italics"/> 194 </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 25<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, touching the ex­<lb/>pan&longs;ion and gravity of the Air under wa­<lb/>ter.<emph.end type="italics"/> 195 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 26<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, touching the Vi­<lb/>brations of a<emph.end type="italics"/> Pendulum. </s> <s>202 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 27<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, touching the pro­<lb/>pagation of &longs;ound: And the Authors inten­<lb/>tion of trying &longs;ome other Experiments, for <lb/>the further elucidation thereof.<emph.end type="italics"/> 210 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 28 <emph type="italics"/>Experiment, touching the &longs;udden <lb/>cruption of Bubbles from the water, when <lb/>the airs pre&longs;&longs;ure was &longs;peedily remov'd.<emph.end type="italics"/> 214 </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 29 <emph type="italics"/>Experiment, touching the cau&longs;e <lb/>of the a&longs;cent of Fumes and Vapors, wherein <lb/>'tis prov'd (from the &longs;everal motions, which <lb/>the Fumes of a &longs;trange &longs;moaking Liquor, of <lb/>the Authors, were ob&longs;erv'd to have in the Re­<lb/>ceiver, upon the ex&longs;uction of the Air) that <lb/>the rea&longs;on of their a&longs;cent proceeds from the <lb/>gravity of the ambient air, and not from any <lb/>po&longs;itive levity of their own.<emph.end type="italics"/> 217 &c. </s></p><pb xlink:href="013/01/029.jpg"/><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 30 <emph type="italics"/>Experiment, concerning the na­<lb/>ture of a fluid Body, illu&longs;trated by the exam­<lb/>ple of &longs;moak which in &longs;everal circum&longs;tances <lb/>&longs;eems very much to re&longs;emble the property of a <lb/>fluid Body,<emph.end type="italics"/> 224 &c. <emph type="italics"/>A conjecture of the <lb/>cau&longs;e of the Suns undulation.<emph.end type="italics"/> 228 </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 31 <emph type="italics"/>Experiment, concerning the<emph.end type="italics"/> Phæ­<lb/>nomena <emph type="italics"/>of two flat Marbles exactly plain'd <lb/>and wrought together, and the true rea&longs;on <lb/>thereof,<emph.end type="italics"/> 229. <emph type="italics"/>The Authors intention for the <lb/>further pro&longs;ecution thereof, & what hindred <lb/>him; the rea&longs;on why the under Marble did <lb/>not fal from the upper (being onely conjoynd <lb/>with Spirit of Wine) when the Receiver was <lb/>evacuated. </s> <s>And a notable relation concern­<lb/>ing the cohe&longs;ion of flat Bodies.<emph.end type="italics"/> 231 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 32 <emph type="italics"/>Experiment, touching the forcible <lb/>pre&longs;&longs;ure of the Air again&longs;t the outward &longs;u­<lb/>perficies of a Valve, fa&longs;ten'd upon the &longs;top­<lb/>cock of the Receiver. </s> <s>The Diameter of it, <lb/>and the weight it &longs;u&longs;tain'd.<emph.end type="italics"/> 233 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 33 <emph type="italics"/>experiment, touching the great pre&longs;­<lb/>&longs;ure of the Air again&longs;t the under &longs;uperficies <lb/>of the Sucker,<emph.end type="italics"/> 236 &c. <emph type="italics"/>what weight was re­<lb/>qui&longs;ite to depre&longs;s it, & what weight it would <lb/>lift and carry up with it,<emph.end type="italics"/> 239 &c. <emph type="italics"/>what im­<lb/>provement & u&longs;e there may be made of this <lb/>experiment,<emph.end type="italics"/> 242. <emph type="italics"/>A Di&longs;cour&longs;e touching the <lb/>nature of Suction, proving that<emph.end type="italics"/> fuga vacui <lb/><emph type="italics"/>is not the adequate cau&longs;e thereof.<emph.end type="italics"/> 243 &c. </s></p><pb xlink:href="013/01/030.jpg"/><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 34<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, containing &longs;everal <lb/>attempts for the weighing of light Bodies in <lb/>the exhau&longs;ted Receiver.<emph.end type="italics"/> 258 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 35<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, touching the cau&longs;e <lb/>of Filtration, and the ri&longs;ing of Water in<emph.end type="italics"/><lb/>Siphons, 262 &c. <emph type="italics"/>A relation of a new <lb/>kinde of<emph.end type="italics"/> Siphon, <emph type="italics"/>of the Authors, upon <lb/>the occa&longs;ion of trying the Experiment <lb/>lately ob&longs;erv'd by &longs;ome French-men, and fur­<lb/>ther improv'd by him&longs;elf; and &longs;ome conje­<lb/>ctures touching the cau&longs;e of the exhibited<emph.end type="italics"/><lb/>Phænomena. </s> <s>267 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 36<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment, touching the weigh­<lb/>ing of a parcel of Air in the exhau&longs;ted Ve&longs;­<lb/>&longs;el; and &longs;ome other Ob&longs;ervations for the ex­<lb/>plication thereof,<emph.end type="italics"/> 272 &c. <emph type="italics"/>An accidental <lb/>Experiment, tending to the further confir­<lb/>mation of the Authors Reflections upon the <lb/>fir&longs;t Experiment; with a digre&longs;sive Ob&longs;er­<lb/>vation, noting the &longs;ubtil penetrancy of &longs;ome <lb/>Spirits, to exceed by far that of the Air,<emph.end type="italics"/> 275 <lb/>&c. <emph type="italics"/>And &longs;ome other Experiments to &longs;hew the <lb/>difficulty of the ingre&longs;s of the Air into the <lb/>pores or holes of &longs;ome bodies into which Wa­<lb/>ter will readily in&longs;inuate it &longs;elf,<emph.end type="italics"/> 279 &c. <emph type="italics"/>with <lb/>a conjecture at the cau&longs;e thereof,<emph.end type="italics"/> 282. <emph type="italics"/>The <lb/>Author returns to the pro&longs;ecution if the in­<lb/>quiry after the gravity of the Air: But fir&longs;t, <lb/>(upon the occa&longs;ion of the tenacity of a thin<emph.end type="italics"/><pb xlink:href="013/01/031.jpg"/><emph type="italics"/>Bubble of Gla&longs;s) &longs;ets down his thoughts con­<lb/>cerning the &longs;trange exuperancy of &longs;trength <lb/>in Air, agitated by heat, above what the <lb/>&longs;ame has unagitated,<emph.end type="italics"/> 283 &c. <emph type="italics"/>And then pro­<lb/>ceeds to the examination of the weight of the <lb/>Air by an<emph.end type="italics"/> Æolipile, <emph type="italics"/>and compares the re&longs;ult <lb/>thereof, with that of<emph.end type="italics"/> Mer&longs;ennus, 286. <emph type="italics"/>The <lb/>Opinions and Experiments of divers Au­<lb/>thors, and &longs;ome of his own, touching the <lb/>proportion of weight betwixt Water and Air, <lb/>are compar'd and examin'd by the Author,<emph.end type="italics"/><lb/>288. <emph type="italics"/>The re&longs;ult thereof,<emph.end type="italics"/> 290. Mer&longs;ennus <lb/><emph type="italics"/>his ob&longs;ervation reconcil'd, with that of the <lb/>Author; and the proportion between the gra­<lb/>vity of Water and Air about<emph.end type="italics"/> London, 291 <lb/>&c. <emph type="italics"/>After the recital of the Opinions of &longs;e­<lb/>veral Writers, touching the proportion of <lb/>gravity between Water and Quick-&longs;ilver, <lb/>the Author &longs;ets down his own tryals, made <lb/>&longs;everal ways, together with his conclu&longs;ion <lb/>therefrom,<emph.end type="italics"/> 293 &c. <emph type="italics"/>The u&longs;e he makes of this <lb/>inquiry for the ghe&longs;sing at the height of the <lb/>Atmo&longs;phere,<emph.end type="italics"/> 297. <emph type="italics"/>What other Experiments <lb/>are requi&longs;ite to the determination thereof.<emph.end type="italics"/><lb/>299 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 37<emph type="sup"/>th<emph.end type="sup"/> E<emph type="italics"/>xperiment, touching the &longs;trange <lb/>and odde<emph.end type="italics"/> Phænomenon, <emph type="italics"/>of the &longs;udden fla&longs;h­<lb/>es of light in the cavity of the Receiver; the <lb/>&longs;everal circum&longs;tances and difficulties of it,<emph.end type="italics"/><pb xlink:href="013/01/032.jpg"/><emph type="italics"/>with &longs;ome attempts towards the rendering at rea&longs;on <lb/>thereof,<emph.end type="italics"/> 301, &c. <emph type="italics"/>The Difficulty of &longs;o doing fnr­<lb/>ther &longs;hewn from the con&longs;ideration of the various <lb/>changes of Air which doe not immediatly fall un­<lb/>der our &longs;en&longs;es,<emph.end type="italics"/> 315. <emph type="italics"/>this la&longs;t propo&longs;ition prou'd <lb/>by &longs;everall ob&longs;ervations.<emph.end type="italics"/> 316. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 38. <emph type="italics"/>Experiment, touching the freezing of <lb/>water,<emph.end type="italics"/> 319. &c. <emph type="italics"/>Aproblem, (concerning the great <lb/>force wherewith a freezing Liquor extends its &longs;elfe,) <lb/>propo&longs;'d upon the Con&longs;ideration of divers admirable <lb/>effects wrought thereby.<emph.end type="italics"/> 320 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 39. <emph type="italics"/>Experiment, containing an inqui&longs;ition <lb/>after the temperature of the &longs;ub&longs;tance that remain'd <lb/>in the cavity of the Receiver, after the Air was well <lb/>exhau&longs;ted. </s> <s>The relation of a<emph.end type="italics"/> Phænomenon, <emph type="italics"/>&longs;eeming <lb/>to proceed from the &longs;welling of the Gla&longs;s. </s> <s>With an <lb/>adverti&longs;ement concerning the pliablene&longs;s of Gla&longs;s in <lb/>&longs;mall peices.<emph.end type="italics"/> 322. &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 40. <emph type="italics"/>Experiment, touching the difficulty that <lb/>occur'd in making tryall whether rarified Air <lb/>were able to &longs;u&longs;taine flying in&longs;ects.<emph.end type="italics"/> 326. &c </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 41. <emph type="italics"/>Experiment, Exhibiting &longs;everall try­<lb/>alls touching the re&longs;piration of divers &longs;orts of ani­<lb/>malls included in the Receiver,<emph.end type="italics"/> 328, &c. <emph type="italics"/>With a <lb/>digre&longs;&longs;ion containing &longs;ome doubts touching re&longs;pira­<lb/>tion wherein are delivered &longs;everall Experiments re­<lb/>lating thereunto.<emph.end type="italics"/> 335 &c. </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 42. <emph type="italics"/>Experiment, touching the differing o­<lb/>peration of corro&longs;ive Liquors in the emptied Receiver <lb/>and in the open Air.<emph.end type="italics"/> 384 </s></p><p type="main"> <s><emph type="italics"/>The<emph.end type="italics"/> 43. <emph type="italics"/>Experiment, touching the &longs;pontaneous E­<lb/>bullition of warm Liquors in the exhau&longs;ted Receiver.<emph.end type="italics"/> 388 </s></p><p type="main"> <s><emph type="italics"/>The Conclu&longs;ion.<emph.end type="italics"/> 394 <pb xlink:href="013/01/033.jpg"/><pb xlink:href="013/01/034.jpg"/><figure id="id.013.01.034.1.jpg" xlink:href="013/01/034/1.jpg"/><pb xlink:href="013/01/035.jpg"/><figure id="id.013.01.035.1.jpg" xlink:href="013/01/035/1.jpg"/><pb xlink:href="013/01/036.jpg"/><figure id="id.013.01.036.1.jpg" xlink:href="013/01/036/1.jpg"/><pb xlink:href="013/01/037.jpg"/><figure id="id.013.01.037.1.jpg" xlink:href="013/01/037/1.jpg"/></s></p><pb xlink:href="013/01/038.jpg"/><pb xlink:href="013/01/039.jpg"/><pb xlink:href="013/01/040.jpg"/><pb xlink:href="013/01/041.jpg" pagenum="1"/><figure id="id.013.01.041.1.jpg" xlink:href="013/01/041/1.jpg"/><p type="main"> <s><emph type="center"/>TO THE <lb/>LORD <lb/>OF <lb/><emph type="italics"/>DUNGARVAN,<emph.end type="italics"/><lb/>My Honoured and Dear <lb/>NEPHEW.<emph.end type="center"/></s></p><p type="main"> <s><emph type="italics"/>My Dear Lord,<emph.end type="italics"/></s></p><p type="main"> <s>REceiving in your la&longs;t from <lb/><emph type="italics"/>Paris,<emph.end type="italics"/> a de&longs;ire that I would <lb/>adde &longs;ome more Experi­<lb/>ments to tho&longs;e I formerly <lb/>&longs;ent You over: I could not <lb/>be &longs;o much your Servant as I am, without <lb/>looking upon that De&longs;ire as a Com­<lb/>mand; and con&longs;equently, without think­<lb/>ing my &longs;elf obliged to con&longs;ider by what <lb/>&longs;ort of Experiments it might the mo&longs;t ac­<lb/>ceptably be obey'd. </s> <s>And at the &longs;ame <pb xlink:href="013/01/042.jpg" pagenum="2"/>time, perceiving by Letters from &longs;ome <lb/>other Ingenious Per&longs;ons at <emph type="italics"/>Paris,<emph.end type="italics"/> that &longs;e­<lb/>veral of the <emph type="italics"/>Virtuo&longs;i<emph.end type="italics"/> there, were very <lb/>intent upon the examination of the Inte­<lb/>re&longs;t of the Ayr, in hindring the de&longs;cent <lb/>of the Quick-&longs;ilver, in the famous Expe­<lb/>riment touching a <emph type="italics"/>Vacuum:<emph.end type="italics"/> I thought I <lb/>could not comply with your De&longs;ires in a <lb/>more fit and &longs;ea&longs;onable manner, then by <lb/>pro&longs;ecuting and endeavoring to promote <lb/>that noble Experiment of <emph type="italics"/>Torricellius:<emph.end type="italics"/><lb/>and by pre&longs;enting your Lord&longs;hip an ac­<lb/>count of my attempts to illu&longs;trate a &longs;ub­<lb/>ject, about which, it's being &longs;o much di&longs;­<lb/>cour&longs;'d of where you are, together with <lb/>your inbred Curio&longs;ity, and love of Ex­<lb/>perimental Learning, made me &longs;uppo&longs;e <lb/>you &longs;ufficiently inqui&longs;itive. </s></p><p type="main"> <s>And though I pretend not to acquaint <lb/>you, on this occa&longs;ion, with any &longs;tore of <lb/>new Di&longs;coveries yet po&longs;&longs;ibly I &longs;hall be &longs;o <lb/>happy, as to a&longs;&longs;i&longs;t you to <emph type="italics"/>know<emph.end type="italics"/> &longs;omethings <lb/>which you did formerly but <emph type="italics"/>&longs;uppo&longs;e;<emph.end type="italics"/> and <lb/>&longs;hall pre&longs;ent you, if not with new Theo­<lb/>ries, at lea&longs;t with new <emph type="italics"/>Proofs<emph.end type="italics"/> of &longs;uch as <lb/>are not yet become unque&longs;tionable. </s> <s>And <lb/>if what I &longs;hall deliver, have the good for­<lb/>tune to encourage and a&longs;&longs;i&longs;t you to pro&longs;e­<lb/>cute the Hints it will afford, I &longs;hall ac-<pb xlink:href="013/01/043.jpg" pagenum="3"/>count my &longs;elf, in paying of a duty to <lb/>you, to have done a piece of Service to <lb/>the Commonwealth of Learning. </s> <s>Since <lb/>it may highly conduce to the advance­<lb/>ment of that Experimental Philo&longs;ophy, <lb/>the effectual pur&longs;uit of which, requires <lb/>as well a Pur&longs;e as a Brain, to endeere it <lb/>to <emph type="italics"/>hopeful<emph.end type="italics"/> Per&longs;ons of your Quality: who <lb/>may accompli&longs;h many things which o­<lb/>thers can but <emph type="italics"/>wi&longs;h<emph.end type="italics"/> or, at mo&longs;t, but <emph type="italics"/>de&longs;ign,<emph.end type="italics"/><lb/>by being able to imploy the Pre&longs;ents of <lb/>Fortune in the &longs;earch of the My&longs;teries of <lb/>Nature. </s></p><p type="main"> <s>And I am not faintly induc'd to make <lb/>choice of this Subject, rather then any <lb/>of the expected Chymical ones, to enter­<lb/>tain your Lord&longs;hip upon, by the&longs;e two <lb/>Con&longs;iderations: The one, That the Ayr <lb/>being &longs;o nece&longs;&longs;ary to humane Life, that <lb/>not onely the generality of Men, but <lb/>mo&longs;t other Creatures that breath, can­<lb/>not live many <emph type="italics"/>minutes<emph.end type="italics"/> without it; any <lb/>con&longs;iderable di&longs;covery of its Nature, <lb/>&longs;eems likely to prove of moment to <lb/>Man-kinde. </s> <s>And the other is, That the <lb/>Ambient Ayr, being that whereto both <lb/>our own Bodies, and mo&longs;t of the others <lb/>we deal with here below, are almo&longs;t per­<lb/>petually contiguous; not onely its alte-<pb xlink:href="013/01/044.jpg" pagenum="4"/>rations have a notable and manife&longs;t &longs;hare <lb/>in tho&longs;e obvious effects, that men have <lb/>already been invited to a&longs;cribe thereunto <lb/>&longs;uch as are the various di&longs;tempers inci­<lb/>dent to humane Bodies, e&longs;pecially if cra­<lb/>zy, in the Spring, the Autumn, and al&longs;o <lb/>on mo&longs;t of the great and &longs;udden changes <lb/>of Weather) but likewi&longs;e, that the fur­<lb/>ther di&longs;covery of the nature of the Ayr, <lb/>will probably di&longs;cover to us, that it con­<lb/>curs more or le&longs;s to the exhibiting of ma­<lb/>ny <emph type="italics"/>Phænomena,<emph.end type="italics"/> in which it hath hither­<lb/>to &longs;carce been &longs;u&longs;pected to have any inte­<lb/>re&longs;t. </s> <s>So that a True Account of any <lb/>Experiment that is New concerning a <lb/>thing, wherewith we have &longs;uch con&longs;tant <lb/>and nece&longs;&longs;ary intercour&longs;e, may not one­<lb/>ly prove of &longs;ome advantage to humane <lb/>Life, but gratifie Philo&longs;ophers, by pro­<lb/>moting their Speculations on a Subject <lb/>which hath &longs;o much opportunity to &longs;olli­<lb/>cite their Curio&longs;ity. </s></p><p type="main"> <s>And I &longs;hould immediately proceed to <lb/>the mention of my Experiments, but that <lb/>I like too well that worthy &longs;aying of the <lb/>Naturali&longs;t <emph type="italics"/>Pliny, Benignum e&longs;t<emph.end type="italics"/></s></p><p type="main"> <s><arrow.to.target n="marg1"/><lb/><emph type="italics"/>& plenum ingenui pudor is, fateri <lb/>per quos profeceris,<emph.end type="italics"/> not to con­<lb/>form to it, by acquainting your Lord-<pb xlink:href="013/01/045.jpg" pagenum="5"/>&longs;hip, in the fir&longs;t place, with the Hint I <lb/>had of the Engine I am to entertain you <lb/>of. </s> <s>You may be plea&longs;'d to remember, <lb/>that a while before our &longs;eparation in <emph type="italics"/>Eng­<lb/>land,<emph.end type="italics"/> I told you of a Book that I had <lb/>heard of, but not peru&longs;'d, publi&longs;h'd by <lb/>the indu&longs;trious Je&longs;uit <emph type="italics"/>Schottus,<emph.end type="italics"/> wherein <lb/>'twas &longs;aid, He related how that ingenious <lb/>Gentleman <emph type="italics"/>Otto Gericke,<emph.end type="italics"/> Con&longs;ul of <emph type="italics"/>Mag­<lb/>deburg,<emph.end type="italics"/> had lately practiced in <emph type="italics"/>Germany<emph.end type="italics"/> a <lb/>way of emptying Gla&longs;s Ve&longs;&longs;els, by &longs;uck­<lb/>ing out the Ayr at the mouth of the Ve&longs;­<lb/>&longs;el, plung'd under water: And you may <lb/>al&longs;o perhaps remember, that I expre&longs;&longs;'d <lb/>my &longs;elf much delighted with this Expe­<lb/>riment, &longs;ince thereby the great force of <lb/>the external Air (either ru&longs;hing in at the <lb/>open'd Orifice of the empty'd Ve&longs;&longs;el, or <lb/>violently forcing up the Water into it) <lb/>was rendred more obvious and con&longs;picu­<lb/>ous, than in any Experiment that I had <lb/>formerly &longs;een. </s> <s>And though it may appear <lb/>by &longs;ome of tho&longs;e Writings I &longs;ometimes <lb/>fhew'd your Lord&longs;hip, that I had been &longs;ol­<lb/>licitous to try things upon the &longs;ame <lb/>ground; yet in regard this Gentleman <lb/>was before-hand with me in producing <lb/>&longs;uch con&longs;iderable effects, by means of the <lb/>ex&longs;uction of Air, I think my &longs;elf oblig'd <pb xlink:href="013/01/046.jpg" pagenum="6"/>to acknowledge the A&longs;&longs;i&longs;tance, and En­<lb/>couragement the Report of his perfor­<lb/>mances hath afforded me. </s></p><p type="margin"> <s><margin.target id="marg1"/><emph type="italics"/>In <gap/>. <lb/></s> <s>lib.<emph.end type="italics"/> 1.</s></p><p type="main"> <s>But as few inventions happen to be at <lb/>fir&longs;t &longs;o compleat, as not to be either ble­<lb/>mi&longs;hd with &longs;ome deficiencies needful to be <lb/>remedy'd, or otherwi&longs;e capable of im­<lb/>provement: &longs;o when the Engine we <lb/>have been &longs;peaking of, comes to be more <lb/>attentively con&longs;ider'd, there will appear <lb/>two very con&longs;iderable things to be de­<lb/>&longs;ir'd in it. </s> <s>For fir&longs;t, the <emph type="italics"/>Wind-Pump<emph.end type="italics"/> (as <lb/>&longs;ome body not improperly calls it) is &longs;o <lb/>contriv'd, that to evacuate the Ve&longs;&longs;el <lb/>there is requir'd the continual labor of <lb/>two &longs;trong men for divers hours. </s> <s>And <lb/>next (which is an imperfection of much <lb/>greater moment) the Receiver, or Gla&longs;s <lb/>to be empty'd, con&longs;i&longs;ting of one entire <lb/>and uninterrupted Globe and Neck of <lb/>Gla&longs;s; the whole Engine is &longs;o made, that <lb/>things cannot be convey'd into it, where­<lb/>on to try Experiments: So that there <lb/>&longs;eems but little (if any thing) more to be <lb/>expected from it, then tho&longs;e very few <lb/><emph type="italics"/>Phænomena<emph.end type="italics"/> that have been already ob­<lb/>&longs;erv'd by the Author, and Recorded by <lb/><emph type="italics"/>Schottus.<emph.end type="italics"/></s><s> Wherefore to remedy the&longs;e <lb/>Inconveniences, I put both Mr. <emph type="italics"/>G.<emph.end type="italics"/><pb xlink:href="013/01/047.jpg" pagenum="7"/>and <emph type="italics"/>R. Hook<emph.end type="italics"/> (who hath al&longs;o the Honor to <lb/>be known to your Lord&longs;hip, and was with <lb/>me when I had the&longs;e things under con&longs;i­<lb/>deration) to contrive &longs;ome Air Pump, <lb/>that might not, like the other, need to <lb/>be kept under water (which on divers oc­<lb/>ca&longs;ions is inconvenient) & might be more <lb/>ea&longs;ily manag'd: And after an un&longs;ucce&longs;sful <lb/>try all or two of ways propo&longs;'d by o­<lb/>thers, the la&longs;t nam'd Per&longs;on fitted me <lb/>with a Pump, anon to be de&longs;crib'd. </s> <s>And <lb/>thus the fir&longs;t Imperfection of the <emph type="italics"/>German<emph.end type="italics"/><lb/>Engine, was in good mea&longs;ure, though <lb/>not perfectly, remedy'd: And to &longs;upply <lb/>the &longs;econd de&longs;ect, it was con&longs;idered that <lb/>it would not perhaps prove impo&longs;&longs;ible to <lb/>leave in the Gla&longs;s to be empty'd, a hole <lb/>large enough to put in a Mans Arm <lb/>cloath'd; and con&longs;equently other Bodies, <lb/>not bigger then it, or longer then the in­<lb/>&longs;ide of the Ve&longs;&longs;el. </s> <s>And this De&longs;ign <lb/>&longs;eem'd the more hopefull, becau&longs;e I re­<lb/>membred, that having &longs;everal years be­<lb/>fore often made the Experiment <emph type="italics"/>De Va­<lb/>cuo<emph.end type="italics"/> with my own hands; I had, to exa­<lb/>mine &longs;ome conjectures that occurr'd to <lb/>me about it, cau&longs;ed Gla&longs;&longs;es to be made <lb/>with a hole at that end, which u&longs;es to be <lb/>&longs;eal'd up, and had neverthele&longs;s been able <pb xlink:href="013/01/048.jpg" pagenum="8"/>as occa&longs;ion requir'd, to make u&longs;e of &longs;uch <lb/>Tubes, as if no &longs;uch holes had been left <lb/>in them; by devi&longs;ing &longs;topples for them, <lb/>made of the common Plai&longs;ter call'd <emph type="italics"/>Dia­<lb/>chylon:<emph.end type="italics"/> which I rightly enough ghe&longs;&longs;'d, <lb/>would, by rea&longs;on of the exqui&longs;ite com­<lb/>mixtion of its &longs;mall parts, and clo&longs;ene&longs;s <lb/>of its texture, deny all acce&longs;s to the ex­<lb/>ternal Air. </s> <s>Wherefore, &longs;uppo&longs;ing that <lb/>by the help of &longs;uch Plai&longs;ters, carefully <lb/>laid upon the commi&longs;&longs;ures of the &longs;topple <lb/>and hole to be made in the Receiver, the <lb/>external Air might be hindred from in&longs;i­<lb/>nuating it &longs;elf between them into the Ve&longs;­<lb/>&longs;el, we cau&longs;'d &longs;everal &longs;uch Gla&longs;&longs;es, as <lb/>you will finde de&longs;crib'd a little lower, to <lb/>be blown at the Gla&longs;s-hou&longs;e; and though <lb/>we could not get the Work-men to blow <lb/>any of them &longs;o large, or of &longs;o conveni­<lb/>ent a &longs;hape as we would fain have had; yet <lb/>finding one to be tolerably fit, and le&longs;s <lb/>unfit then any of the re&longs;t, we were con­<lb/>tent to make u&longs;e of it in that En­<lb/>gine: Of which, I &longs;uppo&longs;e, you by this <lb/>time expect the De&longs;cription, in order to <lb/>the Recital of the <emph type="italics"/>Phænomena<emph.end type="italics"/> exhibited <lb/>by it. </s></p><p type="main"> <s>To give your Lord&longs;hip then, in the <lb/>fir&longs;t place, &longs;ome account of the Engine it <pb xlink:href="013/01/049.jpg" pagenum="9"/>&longs;elf: It con&longs;i&longs;ts of two principal parts; a <lb/>gla&longs;s Ve&longs;&longs;el, and a Pump to draw the Air <lb/>out of it. </s></p><p type="main"> <s>The former of the&longs;e (which we, with <lb/>the Gla&longs;s men, &longs;hall often call a Receiver, <lb/>for its affinity to the large Ve&longs;&longs;els of that <lb/>name, u&longs;ed by Chymi&longs;ts) con&longs;i&longs;ts of a <lb/>Gla&longs;s with a wide hole at the top, of a <lb/>cover to that hole, and of a &longs;top-cock <lb/>fa&longs;tned to the end of the neck, at the <lb/>bottom. </s></p><p type="main"> <s>The &longs;hape of the Gla&longs;s, you will find <lb/>expre&longs;&longs;'d in the fir&longs;t Figure of the annex­<lb/>ed Scheme. </s> <s>And for the &longs;ize of it, it <lb/>contain'd about 30 Wine Quarts, each of <lb/>them containing near two pound (of 16 <lb/>Ounces to the pound) of water: We <lb/>&longs;hould have been better plea&longs;'d with a <lb/>more capacious Ve&longs;&longs;el, but the Gla&longs;s-men <lb/>profe&longs;&longs;ed them&longs;elves unable to blow a <lb/>larger, of &longs;uch a thickne&longs;s and &longs;hape as <lb/>was requi&longs;ite to our purpo&longs;e. </s></p><p type="main"> <s>At the very top of the Ve&longs;&longs;el, (A) you <lb/>may ob&longs;erve a round hole, who&longs;e Dia­<lb/>meter (B C) is of about four inches; and <lb/>whereof, the Orifice is incircled with a <lb/>lip of Gla&longs;s, almo&longs;t an inch high: For <lb/>the making of which lip, it was requi&longs;ite <lb/>(to mention that upon the by, in ca&longs;e <pb xlink:href="013/01/050.jpg" pagenum="10"/>your Lord&longs;hip &longs;hould have &longs;uch another <lb/>Engine made for you) to have a hollow <lb/>and tapering Pipe of Gla&longs;s drawn out, <lb/>whereof the Orifice above mentioned <lb/>was the Ba&longs;is, and then to have the cone <lb/>cut off with a hot Iron, within about an <lb/>Inch of the Points (B C.) </s></p><p type="main"> <s>The u&longs;e of the lip, is to &longs;u&longs;tain the <lb/>cover delineated in the &longs;econd Figure; <lb/>where (D E) points out a bra&longs;s Ring, &longs;o <lb/>ca&longs;t, as that it doth within and without <lb/>cover the lip (B C) of the fir&longs;t Figure, <lb/>and is cemented on upon it with a &longs;trong <lb/>and clo&longs;e Cement. </s> <s>To the inward taper­<lb/>ing Orifice of this Ring (which is about <lb/>three Inches over) are exqui&longs;itely ground <lb/>the &longs;ides of the Bra&longs;s &longs;topple (F G;) &longs;o <lb/>that the concave &longs;uperficies of the one, <lb/>and the convex of the other, may touch <lb/>one another in &longs;o many places, as may <lb/>leave as little acce&longs;s, as po&longs;&longs;ible, to the ex­<lb/>ternal Air: And in the mid&longs;t of this cover <lb/>is left a hole (H I) of about half an inch <lb/>over, invironed al&longs;o with a ring or &longs;ocket <lb/>of the &longs;ame mettal, and fitted likewi&longs;e <lb/>with a bra&longs;s &longs;topple (K) made in the form <lb/>of the Key of a &longs;top-cock, and exactly <lb/>ground into the hole (H I) it is to fill; &longs;o <lb/>as that though it be turn'd round in the <pb xlink:href="013/01/051.jpg" pagenum="11"/>cavity it po&longs;&longs;e&longs;&longs;es, it will not let in the <lb/>Air, and yet may be put in or taken out <lb/>at plea&longs;ure, for u&longs;es to be hereafter men­<lb/>tioned. </s> <s>In order to &longs;ome of which, it is <lb/>perforated with a little hole, (8) traver&longs;ing <lb/>the whole thickne&longs;s of it at the lower <lb/>end; through which, and a little bra&longs;s <lb/>Ring (L) fa&longs;tned to one &longs;ide, (no matter <lb/>which) of the bottom of the &longs;topple <lb/>(FG) a &longs;tring (8, 9, 10) might pa&longs;s, to <lb/>be imploy'd to move &longs;ome things in the <lb/>capacity of the empty'd Ve&longs;&longs;el; without <lb/>any where un&longs;topping it. </s></p><p type="main"> <s>The la&longs;t thing belonging to our Recei­<lb/>ver, is the &longs;top-cock de&longs;igned in the fir&longs;t <lb/>Figure by (N.) for the better fa&longs;tening <lb/>of which to the neck, and exacter exclu&longs;i­<lb/>on of the Air, there was &longs;oder'd on to <lb/>the &longs;hank of the Cock (X) a Plate of <lb/>Tin, (MTUW) long enough to cover <lb/>the neck of the Receiver. </s> <s>But becau&longs;e <lb/>the cementing of this was a matter of <lb/>&longs;ome difficulty, it will not be ami&longs;s to <lb/>mention here the manner of it, which <lb/>was, That the cavity of the tin Plate was <lb/>fill'd with a melted Cement, made of <lb/>Pitch, Ro&longs;in, and Wood-a&longs;hes, well in­<lb/>corporated; and to hinder this liquid <lb/>Mixture from getting into the Orifice (Z) <pb xlink:href="013/01/052.jpg" pagenum="12"/>of the &longs;hank, (X) that hole was &longs;topt <lb/>with a Cork, to which was fa&longs;tned a &longs;tring, <lb/>whereby it might be pull'd out of the up­<lb/>per Orifice of the Receiver; and then, <lb/>the gla&longs;s neck of the Receiver being well <lb/>warm'd, was thru&longs;t into this Cement, and <lb/>over the &longs;hank whereby it was effected, <lb/>that all the &longs;pace betwixt the tin Plate and <lb/>the Receiver, and betwixt the internal <lb/>&longs;uperficies of the Receiver, and the <lb/>&longs;hanck of the Cock, was filld with the <lb/>Cement; and &longs;o we have di&longs;pach'd the <lb/>fir&longs;t and upper part of the Engine. </s></p><p type="main"> <s>The undermo&longs;t remaining part con&longs;i&longs;ts <lb/>of a Frame, and of a &longs;ucking Pump, or <lb/>as we formerly call'd it, an Air Pump, &longs;up­<lb/>ported by it: The Frame is of Wood, <lb/>&longs;mall, but very &longs;trong, con&longs;i&longs;ting of three <lb/>legs, (111) &longs;o plac'd, that one &longs;ide of <lb/>it may &longs;tand perpendicular, that the free <lb/>motion of the hand may not be hindered. <lb/></s> <s>In the mid&longs;t of which frame, is tran&longs;ver&longs;ly <lb/>nail'd a board, (222) which may not im­<lb/>properly be call'd a Midriff, upon which <lb/>re&longs;ts, and to which is &longs;trongly fa&longs;tned, the <lb/>main part of the Pump it &longs;elf, which is <lb/>the onely thing remaining to be de&longs;cri­<lb/>bed. </s></p><p type="main"> <s>The Pump con&longs;i&longs;ts of four parts, a <pb xlink:href="013/01/053.jpg" pagenum="13"/>hollow Cylindre, a Sucker, a handle to <lb/>move that Sucker, and a Valve. </s></p><p type="main"> <s>The Cylindre was (by a pattern) ca&longs;t <lb/>of bra&longs;s; it is in length about 14 inches, <lb/>thick enough to be very &longs;trong, notwith­<lb/>&longs;tanding the Cylindrical cavity left with­<lb/>in it; this cavity is about three inches <lb/>Diameter, and makes as exact a Cylin­<lb/>dre as the Artificer was able to bore. <lb/></s> <s>This hollow Cylindre is fitted with a &longs;uck­<lb/>er, (4455) con&longs;i&longs;ting of two parts, the <lb/>one (44) &longs;omewhat le&longs;s in Diameter then <lb/>the cavity of the Cylindre, upon which <lb/>is nail'd a good thick piece of tan'd &longs;hoe <lb/>Leather, which will go &longs;o clo&longs;e to the <lb/>Cylindre, that it will need to be very <lb/>forcibly knock'd and ram'd in, if at any <lb/>time it be taken out, which is therefore <lb/>done, that it may the more exactly hin­<lb/>der the Air from in&longs;inuating it &longs;elf be­<lb/>twixt it and the &longs;ides of the Cylindre <lb/>whereon it is to move. </s></p><p type="main"> <s>To the mid&longs;t of this former part of the <lb/>Sucker is &longs;trongly fa&longs;tned the other, <lb/>namely a thick and narrow plate of Iron, <lb/>(55) &longs;omewhat longer then the Cylindre, <lb/>one of who&longs;e edges is &longs;mooth, but at the <lb/>other edge it is indented (as I may &longs;o <lb/>&longs;peak) with a row of teeth delineated in <pb xlink:href="013/01/054.jpg" pagenum="14"/>the Scheme, into who&longs;e intervals are to <lb/>be fitted, the teeth of a &longs;mall Iron nut; <lb/>(<gap/>) (as Trade&longs;-men call it) which is fa&longs;t­<lb/>ned by two &longs;taples (22) to the under &longs;ide <lb/>of the formerly mention'd tran&longs;ver&longs;e <lb/>board (222) on which the Cylindre re&longs;ts, <lb/>and is turn'd to and fro by the third piece <lb/>of this Pump, namely, the handle or <lb/><emph type="italics"/>manubrium,<emph.end type="italics"/> (7) of which the Figure gives <lb/>a &longs;ufficient de&longs;cription. </s></p><p type="main"> <s>The fourth and la&longs;t part of this Cylin­<lb/>dre, is the Valve, (R) con&longs;i&longs;ting of a <lb/>hole bored through at the top of the Cy­<lb/>lindre, a little tapering towards the cavi­<lb/>ty; into which hole is ground a tapering <lb/>Peg of bra&longs;s, to be thru&longs;t in, and taken <lb/>out at plea&longs;ure. </s></p><p type="main"> <s>The Engine being thus de&longs;crib'd, it <lb/>will be requi&longs;ite to adde, that &longs;omething <lb/>is wont to be done before it be &longs;et on <lb/>work, for the more ea&longs;ie moving of the <lb/>Sucker, and for the better exclu&longs;ion of <lb/>the outward Air: which when the Ve&longs;&longs;el <lb/>begins to be exhau&longs;ted, is much more dif­<lb/>ficult to be kept out then one would ea&longs;i­<lb/>ly imagine. </s></p><p type="main"> <s>There mu&longs;t then be fir&longs;t powr'd in at <lb/>the top of the Receiver a little &longs;allad oyl, <lb/>partly to fill up any &longs;mall intervalls that <pb xlink:href="013/01/055.jpg" pagenum="15"/>may happen to be betwixt the contigu­<lb/>ous &longs;urfaces of the internal parts of the <lb/>Stop-cock: And partly that it may be <lb/>the more ea&longs;ie to turn the Key (S) back­<lb/>wards and forwards. </s> <s>Pretty &longs;tore of oyl <lb/>mu&longs;t al&longs;o be pour'd into the Cylindre, <lb/>both that the Sucker may &longs;lip up and <lb/>down in it the more &longs;moothly and freely, <lb/>and that the Air might be the better <lb/>hindred from getting in between them: <lb/>And for the like rea&longs;ons, a little oyl is to <lb/>be u&longs;ed al&longs;o about the Valve. </s> <s>Upon <lb/>which occa&longs;ion, it would not be omitted <lb/>(for it is &longs;trange) that oftentimes, when <lb/>neither the pouring in of water, nor even <lb/>of oyl alone, prov'd capable to make the <lb/>Sucker move ea&longs;ily enough in the Cylin­<lb/>der; a mixture of both tho&longs;e Liquors <lb/>would readily (&longs;ometimes even to admi­<lb/>ration) perform the de&longs;ired effect. </s> <s>And <lb/>la&longs;tly, the bra&longs;s cover of the Receiver, <lb/>being put into the bra&longs;s ring formerly de­<lb/>&longs;crib'd, that no Air may get between <lb/>them, it will be very requi&longs;ite to plai&longs;ter <lb/>over very carefully the upper edges of <lb/>both, with the plai&longs;ter formerly mention­<lb/>ed, or &longs;ome other as clo&longs;e, which is to be <lb/>&longs;pread upon the edges with a hot Iron; <lb/>that being melted, it may run into and <pb xlink:href="013/01/056.jpg" pagenum="16"/>fill up all the crannies, or other little ca­<lb/>vities, at which the Air might otherwi&longs;e <lb/>get entrance. </s></p><p type="main"> <s>All things being thus fitted, and the <lb/>lower &longs;hank (O) of the &longs;top-cock being <lb/>put into the upper Orifice of the Cylin­<lb/>der (&), into which it was exactly ground; <lb/>the Experimenter is fir&longs;t, by turning the <lb/>handle, to force the Sucker to the top of <lb/>the Cylinder, that there may be no Air <lb/>left in the upper part of it: Then &longs;hut­<lb/>ting the Valve with the Plug, and turning <lb/>the other way, he is to draw down the <lb/>Sucker to the bottom of the Cylinder; <lb/>by which motion of the Sucker, the Air <lb/>that was formerly in the Cylinder being <lb/>thru&longs;t out, and none being permitted to <lb/>&longs;ucceed in its room, 'tis manife&longs;t that the <lb/>cavity of the Cylinder mu&longs;t be empty, <lb/>in reference to the Air: So that if there­<lb/>upon the Key of the Stop-cock be &longs;o <lb/>turn'd, as that through the perforation of <lb/>it, a free pa&longs;&longs;age be opened betwixt the <lb/>Cylinder and the Receiver, part of the <lb/>Air formerly contain'd in the Receiver, <lb/>will nimbly de&longs;cend into the Cylinder. <lb/></s> <s>And this Air, being by the turning back <lb/>of the Key hinder'd from the returning <lb/>into the Receiver, may, by the opening <pb xlink:href="013/01/057.jpg" pagenum="17"/>of the Valve, and forcing up of the Suck­<lb/>er to the top of the Cylinder again, be <lb/>driven out into the open Air. </s> <s>And thus <lb/>by the repetition of the motion of the <lb/>Sucker upward and downward, and by op­<lb/>portunely turning the Key, and &longs;topping <lb/>the Valve, as occa&longs;ion requires, more or <lb/>le&longs;s Air may be &longs;uck'd out of the Recei­<lb/>ver, according to the exigency of the Ex­<lb/>periment, and the intention of him that <lb/>makes it. </s></p><p type="main"> <s>Your Lord&longs;hip will, perhaps, think that <lb/>I have been unnece&longs;&longs;arily prolix in this <lb/>fir&longs;t part of my Di&longs;cour&longs;e: But if you <lb/>had &longs;een how many unexpected difficul­<lb/>ties we found to keep out the externall <lb/>Air, even for a little while, when &longs;ome <lb/>con&longs;iderable part of the internal had been <lb/>&longs;uckt out; You would peradventure al­<lb/>low, that I might have &longs;et down more <lb/>circum&longs;tances then I have, without &longs;et­<lb/>ting down any, who&longs;e knowledge, he that <lb/>&longs;hall try the Experiment may not have <lb/>need of. </s> <s>Which is &longs;o true, that, before we <lb/>proceed any further, I cannot think it un­<lb/>&longs;ea&longs;onable to adverti&longs;e Your Lord&longs;hip, <lb/>that there are two chief &longs;orts of Experi­<lb/>ments, which we de&longs;ign'd in our Engine <lb/>to make tryal of: The one, &longs;uch as may <pb xlink:href="013/01/058.jpg" pagenum="18"/>be quickly di&longs;patcht, and therefore may <lb/>be try'd in our Engine, though it leak a <lb/>little; becau&longs;e the Air may be fa&longs;ter drawn <lb/>out, by nimbly plying the Pump, then <lb/>it can get in at undi&longs;cern'd leaks; I &longs;ay at <lb/>undi&longs;cern'd leaks, becau&longs;e &longs;uch as are big <lb/>enough to be di&longs;cover'd can &longs;carce be un­<lb/>ea&longs;ie to be &longs;topt. </s> <s>The other &longs;ort of Ex­<lb/>periments con&longs;i&longs;ts of tho&longs;e that require <lb/>not onely that the internal Air be drawn <lb/>out of the Receiver, but that it be like­<lb/>wi&longs;e for a long time kept out of it. </s> <s>Such <lb/>are the pre&longs;ervation of Animal and o­<lb/>ther Bodies therein, the germination and <lb/>growth of Vegetables, and other tryals <lb/>of &longs;everal &longs;orts, which it is apparent can­<lb/>not be well made unle&longs;s the external Air <lb/>can, for a competent while, be excluded: <lb/>Since even at a very &longs;mall leak there may <lb/>enough get in, to make the <emph type="italics"/>Vacuum<emph.end type="italics"/> &longs;oon <lb/>loo&longs;e that name; by which I here declare <lb/>once for all, that I under&longs;tand not a &longs;pace <lb/>wherein there is no body at all, but &longs;uch <lb/>as is either altogether, or almo&longs;t totally <lb/>void of Air. </s></p><p type="main"> <s>Now this di&longs;tinction of Experiments <lb/>I thought fit to premi&longs;e to the en&longs;uing <lb/>Narratives, becau&longs;e upon tryal, we found <lb/>it &longs;o exceeding (and &longs;carce imaginable) dif-<pb xlink:href="013/01/059.jpg" pagenum="19"/>ficult a matter, to keep out the Air from <lb/>getting at all in at any imperceptible hole <lb/>or flaw what&longs;oever, in a Ve&longs;&longs;el immedi­<lb/>ately &longs;urrounded with the compre&longs;&longs;ed At­<lb/>mo&longs;phere, that in &longs;pight of all our care <lb/>and diligence, we never were able totally <lb/>to exhau&longs;t the Receiver, or keep it when <lb/>it was almo&longs;t empty, any con&longs;iderable <lb/>time, from leaking more or le&longs;s: although <lb/>(as we have lately intimated) by unwearyed <lb/>quickne&longs;s in plying the Pump, the inter­<lb/>nall Air can be much fa&longs;ter drawn out <lb/>then the external can get in, till the Re­<lb/>ceiver come to be almo&longs;t quite empty. <lb/></s> <s>And that's enough to enable men to di&longs;­<lb/>cover hitherto unob&longs;erved <emph type="italics"/>Phænomena<emph.end type="italics"/> of <lb/>Nature. </s></p><p type="main"> <s>The Experiments therefore of the fir&longs;t <lb/>&longs;ort, will, I fear, prove the onely ones <lb/>wherewith my Avocations will allow me <lb/>to entertain Your Lord&longs;hip in this Letter. <lb/></s> <s>For till your further Commands &longs;hall en­<lb/>gage me to undertake, by Gods permi&longs;­<lb/>&longs;ion, &longs;uch an Employment, and more lea­<lb/>&longs;ure &longs;hall better fit me for it, I know not <lb/>whether I &longs;hall be in a condition to try <lb/>what may be done, to enable me to give <lb/>you &longs;ome account of the other &longs;ort of <lb/>Experiments al&longs;o. </s></p><pb xlink:href="013/01/060.jpg" pagenum="20"/><p type="main"> <s>TO proceed now to the <emph type="italics"/>Phænomena,<emph.end type="italics"/><lb/><arrow.to.target n="marg2"/><lb/>exhibited to us by the Engine above <lb/>de&longs;cribed; I hold it not unfit to begin <lb/>with what does con&longs;tantly and regularly <lb/>offer it &longs;elf to our ob&longs;ervation, as depend­<lb/>ing upon the Fabrick of the Engine it &longs;elf, <lb/>and not upon the nature of this or that <lb/>particular Experiment which 'tis employ­<lb/>ed to try. </s></p><p type="margin"> <s><margin.target id="marg2"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 1.</s></p><p type="main"> <s>Fir&longs;t, Then upon the drawing down <lb/>of the Sucker, (the Valve being &longs;hut) the <lb/>Cylindrical &longs;pace, de&longs;erted by the Sucker, <lb/>is left de void of Air; and therefore, up­<lb/>on the turning of the Key, the Air con­<lb/>tained in the Receiver ru&longs;hes into the em­<lb/>ptyed Cylinder, till the Air in both tho&longs;e <lb/>Ve&longs;&longs;els be brought to about an equal <lb/>mea&longs;ure of dilatation. </s> <s>And therefore, <lb/>upon &longs;hutting the Receiver by returning <lb/>the Key, if you open the Valve, and force <lb/>up the Sucker again, you will finde, that <lb/>after this fir&longs;t ex&longs;uction you will drive <lb/>out almo&longs;t a whole Cylinder full of Air: <lb/>But at the following ex&longs;uctions, you will <lb/>draw le&longs;s and le&longs;s of Air out of the Recei­<lb/>ver into the Cylinder, becau&longs;e that there <lb/>will &longs;till remain le&longs;s and le&longs;s Air in the <pb xlink:href="013/01/061.jpg" pagenum="21"/>Receiver it &longs;elf; and con&longs;equently, the <lb/>Particles of the remaining Air, having <lb/>more room to extend them&longs;elves in, will <lb/>le&longs;s pre&longs;s out one another. </s> <s>This you will <lb/>ea&longs;ily perceive, by finding, that you &longs;till <lb/>force le&longs;s and le&longs;s Air out of the Cylin­<lb/>der; &longs;o that when the Receiver is almo&longs;t <lb/>exhau&longs;ted, you may force up the Sucker <lb/>almo&longs;t to the top of the Cylinder, be­<lb/>fore you will need to un&longs;top the Valve to <lb/>let out any Air: And if at &longs;uch time, the <lb/>Valve being &longs;hut, you let go the handle of <lb/>the Pump, you will finde the Sucker for­<lb/>cibly carryed up to the top of the Cylin­<lb/>der, by the protru&longs;ion of the external Air; <lb/>which, being much le&longs;s rarified then that <lb/>within the Cylinder, mu&longs;t have a more <lb/>forcible pre&longs;&longs;ure upon the Sucker, then <lb/>the internal is able to re&longs;i&longs;t: And by this <lb/>means you may know how far you have <lb/>emptyed the Receiver. </s> <s>And to this we <lb/>may adde, on this occa&longs;ion, that con&longs;tant­<lb/>ly upon the turning of the Key to let out <lb/>the Air from the Receiver, into the em­<lb/>ptied Cylinder, there is immediately pro­<lb/>duced a con&longs;iderably brisk noi&longs;e, e&longs;peci­<lb/>ally whil'&longs;t there is any plenty of Air in <lb/>the Receiver. </s></p><pb xlink:href="013/01/062.jpg" pagenum="22"/><p type="main"> <s>For the more ea&longs;ie under&longs;tanding of the <lb/>Experiments tryable by our Engine, I <lb/>thought it not &longs;uperfluous, nor un&longs;ea&longs;on­<lb/>able in the recital of this fir&longs;t of them, to <lb/>in&longs;inuate that notion by which it &longs;eems <lb/>likely that mo&longs;t, if not all, of them will <lb/>prove explicable. </s> <s>Your Lord&longs;hip will <lb/>ea&longs;ily &longs;uppo&longs;e, that the Notion I &longs;peak <lb/>of is, That there is a Spring, or Ela&longs;ti­<lb/>cal power in the Air we live in. </s> <s>By which <lb/><foreign lang="greek">e)latg\r</foreign> or Spring of the Air, that which <lb/>I mean is this: That our Air either con­<lb/>&longs;i&longs;ts of, or at lea&longs;t abounds with, parts of <lb/>&longs;uch a nature, that in ca&longs;e they be bent or <lb/>compre&longs;&longs;'d by the weight of the incum­<lb/>bent part of the Atmo&longs;phere, or by any o­<lb/>ther Body, they do endeavor, as much as <lb/>in them lies, to free them&longs;elves from that <lb/>pre&longs;&longs;ure, by bearing again&longs;t the contigu­<lb/>ous Bodies that keep them bent; and, <lb/>a&longs;&longs;oon as tho&longs;e Bodies are remov'd or <lb/>reduced to give them way, by pre&longs;ently <lb/>unbending and &longs;tretching out them&longs;elves, <lb/>either quite, or &longs;o far forth as the con­<lb/>tiguous Bodies that re&longs;i&longs;t them will per­<lb/>mit, and thereby expanding the whole <lb/>parcel of Air, the&longs;e ela&longs;tical Bodies com­<lb/>po&longs;e. </s></p><pb xlink:href="013/01/063.jpg" pagenum="23"/><p type="main"> <s>This Notion may perhaps be &longs;ome­<lb/>what further explain'd, by conceiving the <lb/>Air near the Earth to be &longs;uch a heap of <lb/>little Bodies, lying one upon another, as <lb/>may be re&longs;embled to a Fleece of Wooll. <lb/></s> <s>For this (to omit other likene&longs;&longs;es betwixt <lb/>them) con&longs;i&longs;ts of many &longs;lender and flexi­<lb/>ble Hairs; each of which, may indeed, <lb/>like a little Spring, be ea&longs;ily bent or roul­<lb/>ed up; but will al&longs;o, like a Spring, be <lb/>&longs;till endeavouring to &longs;tretch it &longs;elf out <lb/>again. </s> <s>For though both the&longs;e Haires, <lb/>and the Aerial Corpu&longs;cles to which we <lb/>liken them, do ea&longs;ily yield to externall <lb/>pre&longs;&longs;ures; yet each of them (by vertue of <lb/>its &longs;tructure) is endow'd with a Power or <lb/>Principle of &longs;elf-Dilatation; by vertue <lb/>whereof, though the hairs may by a Mans <lb/>hand be bent and crouded clo&longs;er together, <lb/>and into a narrower room then &longs;uits be&longs;t <lb/>with the nature of the Body: Yet whil'&longs;t <lb/>the compre&longs;&longs;ion la&longs;ts, there is in the fleece <lb/>they compo&longs;e an endeavour outwards, <lb/>whereby it continually thru&longs;ts again&longs;t the <lb/>hand that oppo&longs;es its Expan&longs;ion. </s> <s>And <lb/>upon the removall of the external pre&longs;­<lb/>&longs;ure, by opening the hand more or le&longs;s, the <lb/>compre&longs;&longs;ed Wooll does, as it were, &longs;pon­<lb/>taneou&longs;ly expand or di&longs;play it &longs;elf towards <pb xlink:href="013/01/064.jpg" pagenum="24"/>the recovery of its former more loo&longs;e and <lb/>free condition, till the Fleece have ei­<lb/>ther regain'd its former Dimen&longs;ions, or <lb/>at lea&longs;t, approach'd them as near as the <lb/>compre&longs;&longs;ing hand (perchance not quite <lb/>open'd) will permit. </s> <s>This Power of <lb/>&longs;elf-Dilatation, is &longs;omewhat more con&longs;pi­<lb/>cuous in a dry Spunge compre&longs;&longs;'d, then <lb/>in a Fleece of Wooll. </s> <s>But yet we ra­<lb/>ther cho&longs;e to imploy the latter, on this <lb/>occa&longs;ion, becau&longs;e it is not like a Spunge, <lb/>an entire Body, but a number of &longs;len­<lb/>der and flexible Bodies, loo&longs;ely com­<lb/>plicated, as the Air it &longs;elf &longs;eems to <lb/>be. </s></p><p type="main"> <s>There is yet another way to explicate <lb/>the Spring of the Air, namely, by &longs;uppo­<lb/>&longs;ing with that mo&longs;t ingenious Gentleman, <lb/>Mon&longs;ieur <emph type="italics"/>Des Cartes,<emph.end type="italics"/> That the Air is no­<lb/>thing but a Congeries or heap of &longs;mall <lb/>and (for the mo&longs;t part) of flexible Parti­<lb/>cles; of &longs;everal &longs;izes, and of all kinde of Fi­<lb/>gures which are rai&longs;'d by heat (e&longs;pecially <lb/>that of the Sun) into that fluid and <lb/>&longs;ubtle Etheriall Body that &longs;urrounds <lb/>the Earth; and by the re&longs;tle&longs;&longs;e agi­<lb/>tation of that Cele&longs;tial Matter where­<lb/>in tho&longs;e Particles &longs;wim, are &longs;o whirl'd <pb xlink:href="013/01/065.jpg" pagenum="25"/>round, that each Corpu&longs;cle endeavours <lb/>to beat off all others from coming within <lb/>the little Sphear requi&longs;ite to its motion <lb/>about its own Center; and (in ca&longs;e any, <lb/>by intruding into that Sphear &longs;hall op­<lb/>po&longs;e its free Rotation) to expell or drive <lb/>it away: So that according to this Do­<lb/>ctrine, it imports very little, whether the <lb/>particles of the Air have the &longs;tructure re­<lb/>qui&longs;ite to Springs, or be of any other <lb/>form (how irregular &longs;oever) &longs;ince their <lb/>Ela&longs;tical power is not made to depend <lb/>upon their &longs;hape or &longs;tructure, but upon <lb/>the vehement agitation, and (as it were) <lb/>brandi&longs;hing motion, which they receive <lb/>from the fluid <emph type="italics"/>Ether<emph.end type="italics"/> that &longs;wiftly flows <lb/>between them, and whirling about each <lb/>of them (independently from the re&longs;t) <lb/>not onely keeps tho&longs;e &longs;lender Aërial <lb/>Bodies &longs;eparated and &longs;tretcht out (at lea&longs;t, <lb/>as far as the Neighbouring ones will per­<lb/>mit) which otherwi&longs;e, by rea&longs;on of <lb/>their flexiblene&longs;s and weight, would <lb/>flag or curl; but al&longs;o makes them hit <lb/>again&longs;t, and knock away each other, and <lb/>con&longs;equently require more room, then <lb/>that which if they were compre&longs;&longs;'d, they <lb/>would take up. </s></p><pb xlink:href="013/01/066.jpg" pagenum="26"/><p type="main"> <s>By the&longs;e two differing ways, my Lord, <lb/>may the Spring of the Air be explicated. <lb/></s> <s>But though the former of them be that, <lb/>which by rea&longs;on of its &longs;eeming &longs;omewhat <lb/>more ea&longs;ie, I &longs;hall for the mo&longs;t part make <lb/>u&longs;e of in the following Di&longs;cour&longs;e: yet <lb/>am I not willing to declare peremptorily <lb/>for either of them, again&longs;t the other. </s> <s>And <lb/>indeed, though I have in another Treati&longs;e <lb/>endeavoured to make it probable, that the <lb/>returning of Ela&longs;tical Bodies (if I may &longs;o <lb/>call them) forcibly bent, to their former <lb/>po&longs;ition, may be Mechanically explica­<lb/>ted: Yet I mu&longs;t confe&longs;s, that to deter­<lb/>mine whether the motion of Re&longs;titution <lb/>in Bodies, proceed from this, That the <lb/>parts of a Body of a peculiar Structure <lb/>are put into motion by the bending of the <lb/>&longs;pring, or from the endeavor of &longs;ome &longs;ub­<lb/>tle ambient Body, who&longs;e pa&longs;&longs;age may be <lb/>oppo&longs;'d or ob&longs;tructed, or el&longs;e it's pre&longs;&longs;ure <lb/>unequally re&longs;i&longs;ted by rea&longs;on of the new <lb/>&longs;hape or magnitude, which the bending of <lb/>a Spring may give the Pores of it: To <lb/>determine this, I &longs;ay, &longs;eems to me a mat­<lb/>ter of more difficulty, then at fir&longs;t &longs;ight <lb/>one would ea&longs;ily imagine it. </s> <s>Wherefore <lb/>I &longs;hall decline medling with a &longs;ubject, <lb/>which is much more hard to be explica-<pb xlink:href="013/01/067.jpg" pagenum="27"/>ted, then nece&longs;&longs;ary to be &longs;o, by him, <lb/>who&longs;e bu&longs;ine&longs;s it is not, in this Letter, to <lb/>a&longs;&longs;ign the adequate cau&longs;e of the Spring of <lb/>the Air, but onely to manife&longs;t, That the <lb/>Air has a Spring, and to relate &longs;ome of <lb/>its effects. </s></p><p type="main"> <s>I know not whether I need annex that, <lb/>though either of the above-mention'd <lb/>Hypothe&longs;es, and perhaps &longs;ome others, <lb/>may afford us an account plau&longs;ible enough <lb/>of the Air-&longs;pring; yet I doubt, whether <lb/>any of them gives us a &longs;ufficient account <lb/>of its Nature. </s> <s>And of this doubt, I <lb/>might here mention &longs;ome Rea&longs;ons, but <lb/>that, peradventure, I may (God permit­<lb/>ting) have a fitter occa&longs;ion to &longs;ay &longs;ome­<lb/>thing of it el&longs;ewhere. </s> <s>And therefore I <lb/>&longs;hould now proceed to the next Experi­<lb/>ment, but that I think it requi&longs;ite, fir&longs;t, <lb/>to &longs;ugge&longs;t to your Lord&longs;hip what comes <lb/>into my thoughts, by way of An&longs;wer to <lb/>a plau&longs;ible Objection, which I fore&longs;ee you <lb/>may make again&longs;t our propo&longs;'d Doctrine, <lb/>touching the Spring of the Air. </s> <s>For it <lb/>may be alleadged, that though the Air <lb/>were granted to con&longs;i&longs;t of Springy Par­<lb/>ticles (if I may &longs;o &longs;peak) yet thereby <lb/>we could onely give an account of the <lb/>Dilatation of the Air in Wine-Guns and <pb xlink:href="013/01/068.jpg" pagenum="28"/>other pneumatical Engines wherein the <lb/>Air has been compre&longs;&longs;'d, and its Springs <lb/>violently bent by an apparent externall <lb/>force; upon the removall of which, 'tis <lb/>no wonder that the Air &longs;hould, by the <lb/>motion of re&longs;titution, expand it &longs;elf till <lb/>it have recovered its more natural dimen­<lb/>&longs;ions: whereas in our above-mentioned <lb/>fir&longs;t Experiment, and in almo&longs;t all others <lb/>tryable in our Engine, it appears not <lb/>that any compre&longs;&longs;ion of the Air prece­<lb/>ded its &longs;pontaneous Dilatation or Expan­<lb/>&longs;ion of it &longs;elf. </s> <s>To remove this difficul­<lb/>ty, I mu&longs;t de&longs;ire Your Lord&longs;hip to take <lb/>notice, that of whatever nature the Air, <lb/>very remote from the Earth, may be, and <lb/>whatever the Schools may confidently <lb/>teach to the contrary, yet we have divers <lb/>Experiments to evince, that the Atmo&longs;­<lb/>phere we live in is not (otherwi&longs;e then <lb/>comparatively to more ponderous Bodies) <lb/>light, but heavy: And did not their <lb/>gravity hinder them, it appears not why <lb/>the &longs;teams of the Terraqueous Globe, of <lb/>which our Air in great part con&longs;i&longs;ts, <lb/>&longs;hould not ri&longs;e much higher then the Re­<lb/>fraction of the Sun, and other Stars <lb/>give men ground to think, that the At­<lb/>mo&longs;phere, even in the judgement of tho&longs;e <pb xlink:href="013/01/069.jpg" pagenum="29"/>Recent A&longs;tronomers, who &longs;eem willing <lb/>to enlarge its bounds as much as they dare, <lb/>does reach. </s></p><p type="main"> <s>But le&longs;t you &longs;hould expect my &longs;econding <lb/>this Rea&longs;on by Experience; and le&longs;t you <lb/>&longs;hould object, That mo&longs;t of the <expan abbr="Experi-m&etilde;ts">Experi­<lb/>ments</expan> that have been propo&longs;'d to prove the <lb/>gravity of the Air, have been either barely <lb/>propo&longs;'d, or perhaps not accuratly try'd; I <lb/>am content, before I pa&longs;s further, to menti­<lb/>on here, That I found a dry lambs-bladder <lb/>containing near about two thirds of a pint, <lb/>and compre&longs;&longs;'d by a packthred tyed about <lb/>it, to loo&longs;e a grain and the eighth part of <lb/>a grain of its former weight, by the rece&longs;s <lb/>of the Air upon my having prickt it: And <lb/>this with a pair of Scales, which when the <lb/>full Bladder and the corre&longs;pondent weight <lb/>were in it, would manife&longs;tly turn either <lb/>way with the 32 part of a grain. </s> <s>And if <lb/>it be further objected, That the Air in <lb/>the Bladder was violently compre&longs;&longs;'d by <lb/>the Pack-thred and the &longs;ides of the <lb/>Bladder, we might probably (to wave <lb/>prolix an&longs;wers) be furni&longs;h'd with a Re­<lb/>ply, by &longs;etting down the differing weight <lb/>of our Receiver, when empty'd and when <lb/>full of uncompre&longs;&longs;'d Air, if we could here <lb/>procure &longs;cales fit for &longs;o nice an experiment; <pb xlink:href="013/01/070.jpg" pagenum="30"/>&longs;ince we are informed, that in the <emph type="italics"/>German<emph.end type="italics"/><lb/>Experiment, commended at the begin­<lb/>ning of this Letter, the Ingenious Tryers <lb/>of it found, That their Gla&longs;s Ve&longs;&longs;el, of <lb/>the capacity of 32 mea&longs;ures, was lighter <lb/>when the Air had been drawn out of it, <lb/>then before, by no le&longs;s then one ounce <lb/>and (3/10) that is, an ounce and very near a <lb/>third: But of the gravity of the Air, we <lb/>may el&longs;ewhere have occa&longs;ion to make fur­<lb/>ther mention. </s></p><p type="main"> <s>Taking it then for granted that the Air <lb/>is not deyoid of weight, it will not be <lb/>unea&longs;ie to conceive, that that part of the <lb/>Atmo&longs;phere wherein we live, being the <lb/>lower part of it, the Corpu&longs;cles that com­<lb/>po&longs;e it, are very much compre&longs;&longs;'d by the <lb/>weight of all tho&longs;e of the like nature that <lb/>are directly over them, that is, of all the <lb/>Particles of Air, that being pil'd up up­<lb/>on them, reach to the top of the Atmo&longs;­<lb/>phere. </s> <s>And though the height of this <lb/>Atmo&longs;phere, according to the famous <lb/><emph type="italics"/>Kepler,<emph.end type="italics"/> and &longs;ome others, &longs;carce exceeds <lb/>eight common miles; yet other eminent <lb/>and later A&longs;tronomers, would promote <lb/>the confines of the Atmo&longs;phere, to ex­<lb/>ceed &longs;ix or &longs;even times that number of <lb/>miles. </s> <s>And the diligent and learned <pb xlink:href="013/01/071.jpg" pagenum="31"/><emph type="italics"/>Riviolo<emph.end type="italics"/> makes it probable, that the At­<lb/>mo&longs;phere may, at lea&longs;t in divers places, be <lb/>at lea&longs;t 50 miles high. </s> <s>So that according to <lb/>a moderate e&longs;timate of the thickne&longs;s of <lb/>the Atmo&longs;phere, we may well &longs;uppo&longs;e, <lb/>that a Column of Air, of many miles in <lb/>height, leaning upon &longs;ome &longs;pringy Cor­<lb/>pu&longs;cles of Air here below, may have <lb/>weight enough to bend their little &longs;prings, <lb/>and keep them bent: As, to re&longs;ume our <lb/>former compari&longs;on, if there were fleeces of <lb/>Wooll pil'd up to a mountainous height <lb/>upon one another, the Hairs that com­<lb/>po&longs;e the lowermo&longs;t locks which &longs;upport <lb/>the re&longs;t, would, by the weight of all the <lb/>Wool above them, be as well &longs;trongly <lb/>compre&longs;&longs;ed, as if a man &longs;hould &longs;queeze <lb/>them together in his hands, or imploy any <lb/>&longs;uch other moderate force to compre&longs;s <lb/>them. </s> <s>So that we need not wonder, that <lb/>upon the taking off the incumbent Air <lb/>from any parcel of the Atmo&longs;phere here <lb/>below, the Corpu&longs;cles, whereof that un­<lb/>dermo&longs;t Air con&longs;i&longs;ts, &longs;hould di&longs;play them­<lb/>&longs;elves, and take up more room then be­<lb/>fore. </s></p><p type="main"> <s>And if it be objected, That in Water, <lb/>the weight of the upper and of the lower <lb/>part is the &longs;ame: I an&longs;wer, That be&longs;ides <pb xlink:href="013/01/072.jpg" pagenum="32"/>that it may be well doubted whether the <lb/>ob&longs;ervation, by rea&longs;on of the great diffi­<lb/>culty have been exactly made, there is a <lb/>manife&longs;t di&longs;parity betwixt the Air and <lb/>Water: For I have not found, that upon <lb/>an Experiment purpo&longs;ely made, (and in <lb/>another Treati&longs;e Recorded) that Water <lb/>will &longs;uffer any con&longs;iderable compre&longs;&longs;ion; <lb/>whereas we may ob&longs;erve in Wind-Guns <lb/>(to mention now no other Engines) that <lb/>the Air will &longs;uffer it &longs;elf to be crouded in­<lb/>to a comparatively very little room; in <lb/>&longs;o much, that a very diligent Examiner <lb/>of the <emph type="italics"/>Phænomena<emph.end type="italics"/> of Wind-Guns would <lb/>have us believe, that in one of them, by <lb/>conden&longs;ation, he reduc'd the Air into a <lb/>&longs;pace at lea&longs;t eight times narrower then it <lb/>before po&longs;&longs;e&longs;t. </s> <s>And to this, if we adde <lb/>a noble <emph type="italics"/>Phænomenon<emph.end type="italics"/> of the Experiment <lb/><emph type="italics"/>De Vacuo;<emph.end type="italics"/> the&longs;e things put together, may <lb/>for the pre&longs;ent &longs;uffice to countenance our <lb/>Doctrine. </s> <s>For that noble Experimenter, <lb/>Mon&longs;ieur <emph type="italics"/>Pa&longs;cal<emph.end type="italics"/> (the Son) had the com­<lb/>mendable Curio&longs;ity to cau&longs;e the <emph type="italics"/>Torri­<lb/>cellian<emph.end type="italics"/> Experiment to be try'd at the foot, <lb/>about the middle, and at the top of that <lb/>high Mountain (in <emph type="italics"/>Auvergne,<emph.end type="italics"/> if I mi&longs;take <lb/>not) commonly call'd <emph type="italics"/>Le Puy de Domme;<emph.end type="italics"/><lb/>whereby it was found, That the <emph type="italics"/>Mercury<emph.end type="italics"/><pb xlink:href="013/01/073.jpg" pagenum="33"/>in the Tube fell down lower, about three <lb/>inches, at the top of the Mountain then <lb/>at the bottom. </s> <s>And a Learned Man a <lb/>while &longs;ince inform'd me, That a great <lb/><emph type="italics"/>Virtuo&longs;o,<emph.end type="italics"/> friend to us both, has, with not <lb/>unlike &longs;ucce&longs;s, tryed the &longs;ame Experi­<lb/>ment in the lower and upper parts of a <lb/>Mountain in the We&longs;t of <emph type="italics"/>England:<emph.end type="italics"/> Of <lb/>which, the rea&longs;on &longs;eems manife&longs;tly enough <lb/>to be this, That upon the tops of high <lb/>Mountains, the Air which bears again&longs;t <lb/>the re&longs;tagnant Quick-&longs;ilver, is le&longs;s pre&longs;&longs;'d <lb/>by the le&longs;s ponderous incumbent Air; and <lb/>con&longs;equently is not able totally to hinder <lb/>the de&longs;cent of &longs;o tall and heavy a Cylin­<lb/>der of Quick-&longs;ilver, as at the bottom of <lb/>&longs;uch Mountains did but maintain an <emph type="italics"/>Æqui­<lb/>librium<emph.end type="italics"/> with the incumbent Atmo&longs;phere. </s></p><p type="main"> <s>And if it be yet further Objected a­<lb/>gain&longs;t what hath been propo&longs;'d touching <lb/>the compactne&longs;s and pre&longs;&longs;ure of the Infe­<lb/>rior Air; That we finde this very Air to <lb/>yield readily to the motion of little Flies, <lb/>and even to that of Feathers, and &longs;uch o­<lb/>ther light and weak Bodies; which &longs;eems <lb/>to argue, that the particles of our Air are <lb/>not &longs;o compre&longs;&longs;'d as we have repre&longs;ented <lb/>them, e&longs;pecially, &longs;ince by our former <lb/>Experiment it appears, that the Air rea-<pb xlink:href="013/01/074.jpg" pagenum="34"/>dily dilated it &longs;elf downward, from the <lb/>Receiver into the Pump, when 'tis plain, <lb/>that it is not the incumbent Atmo&longs;phere, <lb/>but onely the &longs;ubjacent Air in the bra&longs;s <lb/>Cylinder that has been remov'd: If this, <lb/>I &longs;ay, be objected, we may reply, That <lb/>when a man &longs;queezes a Fleece of Wool in <lb/>his hand, he may feel that the Wool in­<lb/>ce&longs;&longs;antly bears again&longs;t his hand, as that <lb/>which hinders the hairs it con&longs;i&longs;ts of, to <lb/>recover their former and more natural ex­<lb/>tent. </s> <s>So each parcel of the Air about the <lb/>Earth, does con&longs;tantly endeavour to thru&longs;t <lb/>away all tho&longs;e contiguous Bodies, whe­<lb/>ther Aërial or more gro&longs;s, that keep <lb/>them bent, and hinder the expan&longs;ion of <lb/>its parts, which will dilate them&longs;elves or <lb/>flie abroad towards that part, whether up­<lb/>wards or downwards, where they finde <lb/>their attempted Dilatation of them&longs;elves <lb/>le&longs;s re&longs;i&longs;ted by the neihgboring Bodies. <lb/></s> <s>Thus the Corpu&longs;cles of that Air we have <lb/>been all this while &longs;peaking of, being un­<lb/>able, by rea&longs;on of their weight, to a&longs;cend <lb/>above the Convexity of the Atmo&longs;phere, <lb/>and by rea&longs;on of the re&longs;i&longs;tance of the &longs;ur­<lb/>face of the Earth and Water, to fall down <lb/>lower, they are forced, by their own gra­<lb/>vity and this re&longs;i&longs;tance, to expand and <pb xlink:href="013/01/075.jpg" pagenum="35"/>diffu&longs;e them&longs;elves about the Terre&longs;tial <lb/>Globe; whereby it comes to pa&longs;s, that <lb/>they mu&longs;t as well pre&longs;s the contiguous <lb/>Corpu&longs;cles of Air that on either &longs;ide op­<lb/>po&longs;e their Dilatation, as they mu&longs;t pre&longs;s <lb/>upon the &longs;urface of the Earth, and, as it <lb/>were recoyling thence, endeavor to thru&longs;t <lb/>away tho&longs;e upper particles of Air that <lb/>lean upon them. </s></p><p type="main"> <s>And as for the ea&longs;ie yielding of the Air <lb/>to the Bodies that move in it, if we con­<lb/>&longs;ider that the Corpu&longs;cles whereof it con­<lb/>&longs;i&longs;ts, though of a &longs;pringy nature, are yet <lb/>&longs;o very &longs;mall, as to make up (which 'tis <lb/>manife&longs;t they doe) a fluid Body, it will <lb/>not be difficult to conceive, that in the <lb/>Air, as in other Bodies that are fluid, the <lb/>little Bodies it con&longs;i&longs;ts of are in an almo&longs;t <lb/>re&longs;tle&longs;s motion, whereby they become <lb/>(as we have more fully di&longs;cour&longs;ed in ano­<lb/><arrow.to.target n="marg3"/><lb/>ther Treati&longs;e) very much di&longs;po&longs;ed to <lb/>yield to other Bodies, or ea&longs;ie to be di&longs;­<lb/>plac'd by them, and that the &longs;ame Cor­<lb/>pu&longs;cles are likewi&longs;e &longs;o variou&longs;ly mov'd, as <lb/>they are intire Corpu&longs;cles, that if &longs;ome <lb/>&longs;trive to pu&longs;h a Body plac'd among them <lb/>towards the right hand (for in&longs;tance) <lb/>others, who&longs;e motion has an oppo&longs;ite de­<lb/>termination, as &longs;trongly thru&longs;t the &longs;ame <pb xlink:href="013/01/076.jpg" pagenum="36"/>Body towards the left; whereby neither <lb/>of them proves able to move it out of <lb/>its place, the pre&longs;&longs;ure on all hands being <lb/>reduced as it were to an <emph type="italics"/>Æquilibrium:<emph.end type="italics"/> &longs;o <lb/>that the Corpu&longs;cles of the Air mu&longs;t be as <lb/>well &longs;ometimes con&longs;idered under the no­<lb/>tion of little Springs, which remaining <lb/>bent, are in their entire bulk tran&longs;ported <lb/>from place to place; as under the notion <lb/>of Springs di&longs;playing them&longs;elves, who&longs;e <lb/>parts flie abroad whil&longs;t as to their entire <lb/>bulk they &longs;carce change place: As the <lb/>two ends of a Bow, &longs;hot off, fly from one <lb/>another, whereas the Bow it &longs;elf may be <lb/>held fa&longs;t in the Archers hand; and that it <lb/>is the equal pre&longs;&longs;ure of the Air on all &longs;ides <lb/>upon the Bodies that are in it, which cau­<lb/>&longs;es the ea&longs;ie Ce&longs;&longs;ion of its parts, may be <lb/>argu'd from hence: That if by the help <lb/>of our Engine the Air be but in great <lb/>part, though not totally drawn away <lb/>from one &longs;ide of a Body without being <lb/>drawn away from the other; he that &longs;hall <lb/>think to move that Body too and fro, as <lb/>ea&longs;ily as before, will finde him&longs;elf much <lb/>mi&longs;taken. </s></p><p type="margin"> <s><margin.target id="marg3"/><emph type="italics"/>In a Di&longs;­<lb/>cour&longs;e <lb/>touching <lb/>&longs;luidity <lb/>and firm­<lb/>ne&longs;s.<emph.end type="italics"/></s></p><p type="main"> <s>In verification of which we will, to di­<lb/>vert your Lord&longs;hip a little, mention here <lb/>a <emph type="italics"/>Phænomenon<emph.end type="italics"/> of our Engine, which even <pb xlink:href="013/01/077.jpg" pagenum="37"/>to divers ingenious per&longs;ons has at fir&longs;t <lb/>&longs;ight &longs;eem'd very wonderful. </s></p><p type="main"> <s>THe thing that is wont to be admired, <lb/><arrow.to.target n="marg4"/><lb/>and which may pa&longs;s for our &longs;econd <lb/>Experiment is this, That if, when the <lb/>Receiver is almo&longs;t empty, a By-&longs;tander <lb/>be de&longs;ired to lift up the bra&longs;s Key (former­<lb/>ly de&longs;cribed as a &longs;topple in the bra&longs;s Co­<lb/>ver) he will finde it a very difficult thing <lb/>to do &longs;o, if the Ve&longs;&longs;el be well exhau&longs;ted; <lb/>and even when but a moderate quantity of <lb/>Air has been drawn out, he will, when he <lb/>has lifted it up a little, &longs;o that it is &longs;ome­<lb/>what loo&longs;e from the &longs;ides of the lip or <lb/>&longs;ocket, which (with the help of a little <lb/>oyl) it exactly filled before, he will (I &longs;ay) <lb/>finde it &longs;o difficult to be lifted up, that <lb/>he will imagine there is &longs;ome great weight <lb/>fa&longs;tned to the bottom of it. </s> <s>And if (as <lb/>&longs;ometimes has been done for merriment) <lb/>onely a Bladder be tyed to it, it is plea­<lb/>&longs;ant to &longs;ee how men will marvail that &longs;o <lb/>light a Body, filled at mo&longs;t but with Air, <lb/>&longs;hould &longs;o forcibly draw down their hand <lb/>as if it were fill'd with &longs;ome very ponder­<lb/>ous thing: whereas the cau&longs;e of this pret­<lb/>ty <emph type="italics"/>Phænomenon<emph.end type="italics"/> &longs;eems plainly enough to <pb xlink:href="013/01/078.jpg" pagenum="38"/>be onely this, That the Air in the Recei­<lb/>ver, being very much dilated, its Spring <lb/>mu&longs;t be very much weakn'd, and con&longs;e­<lb/>quently it can but faintly pre&longs;s up the <lb/>lower end of the &longs;topple, whereas the <lb/>Spring of the external Air being no way <lb/>debilitated, he that a little lifts up the <lb/>&longs;topple mu&longs;t with his hand &longs;upport a pre&longs;­<lb/>&longs;ure equal to the di&longs;proportion betwixt <lb/>the force of the internal expanded Air, and <lb/>that of the Atmo&longs;phere incumbent upon <lb/>the upper part of the &longs;ame key or &longs;topple: <lb/>And &longs;o men being unu&longs;'d to finde any re­<lb/>&longs;i&longs;tance, in lifting things up, from the <lb/>free Air above them, they are forward to <lb/>conclude that that which depre&longs;&longs;es their <lb/>hands mu&longs;t needs be &longs;ome weight, though <lb/>they know not where plac'd, drawing be­<lb/>neath it. </s></p><p type="margin"> <s><margin.target id="marg4"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 2.</s></p><p type="main"> <s>And that we have not mi&longs;-a&longs;&longs;ign'd the <lb/>cau&longs;e of this <emph type="italics"/>Phænomenon<emph.end type="italics"/> &longs;eems evident <lb/>enough by this; That as Air is &longs;uffer­<lb/>ed by little and little to get into the Re­<lb/>ceiver, the weight that a man fancies his <lb/>hand &longs;upports is manife&longs;tly felt to decrea&longs;e <lb/>more and more, the internal Air by this <lb/>recruit approaching more to an <emph type="italics"/>Æquili­<lb/>brium<emph.end type="italics"/> with the external, till at length the <lb/>Receiver growing again full of Air, the <pb xlink:href="013/01/079.jpg" pagenum="39"/>&longs;topple may be lifted up without any dif­<lb/>ficulty at all. </s></p><p type="main"> <s>By &longs;everal other of the Experiments <lb/>afforded us by our Engine, the &longs;ame no­<lb/>tion of the great and equal pre&longs;&longs;ure of the <lb/>free Air upon the Bodies it environs, <lb/>might be here manife&longs;ted, but that we <lb/>think it not &longs;o fit to anticipate &longs;uch Ex­<lb/>periments: And therefore &longs;hall rather <lb/>employ a few lines to clear up a difficulty <lb/>touching this matter, which we have ob­<lb/>&longs;erv'd to have troubled &longs;ome even of the <lb/>Philo&longs;ophical and Mathematical Specta­<lb/>tors of our Engine, who have wonder'd <lb/>that we &longs;hould talk of the Air exqui&longs;itely <lb/>&longs;hut up in our Receiver, as if it were all <lb/>one with the pre&longs;&longs;ure of the Atmo&longs;phere; <lb/>whereas the thick and clo&longs;e body of the <lb/>Gla&longs;s, wholly impervious to the Air, does <lb/>manife&longs;tly keep the incumbent Pillar of <lb/>the Atmo&longs;phere from pre&longs;&longs;ing in the lea&longs;t <lb/>upon the Air within the Gla&longs;s, which it <lb/>can no where come to touch. </s> <s>To eluci­<lb/>date a little this matter, let us con&longs;ider, <lb/>That if a man &longs;hould take a fleece of <lb/>Wool, and having fir&longs;t by compre&longs;&longs;ing it <lb/>in his hand reduc'd it into a narrower com­<lb/>pa&longs;s, &longs;hould nimbly convey and &longs;hut it <lb/>clo&longs;e up into a Box ju&longs;t fit for it, though <pb xlink:href="013/01/080.jpg" pagenum="40"/>the force of his hand would then no lon­<lb/>ger bend tho&longs;e numerous &longs;pringy Body's <lb/>that compo&longs;e the Fleece, yet they would <lb/>continue as &longs;trongly bent as before, be­<lb/>cau&longs;e the Box they are inclo&longs;'d in would <lb/>as much re&longs;i&longs;t their re-expanding of <lb/>them&longs;elves, as did the hand that put them <lb/>in. </s> <s>For thus we may conceive, that the <lb/>Air being &longs;hut up, when its parts are bent <lb/>by the whole weight of the incumbent <lb/>Atmo&longs;phere, though that weight can no <lb/>longer lean upon it, by rea&longs;on it is kept <lb/>off by the Gla&longs;s, yet the Corpu&longs;cles of <lb/>the Air within that Gla&longs;s continue as <lb/>forcibly bent as they were before their in­<lb/>clu&longs;ion, becau&longs;e the &longs;ides of the Gla&longs;s <lb/>hinder them from di&longs;playing or &longs;tretch­<lb/>ing out them&longs;elves. </s> <s>And if it be ob­<lb/>jected that this is unlikely, becau&longs;e ev'n <lb/>Gla&longs;s bubles, &longs;uch as are wont to be <lb/>blown at the flame of a Lamp, exceeding <lb/>thin and Hermetically &longs;eal'd will not <lb/>break; whereas it cannot be imagin'd <lb/>that &longs;o thin a Pri&longs;on of Gla&longs;s could re­<lb/>&longs;i&longs;t the Ela&longs;tical force of all the included <lb/>Air, if that Air were &longs;o compre&longs;&longs;'d as we <lb/>&longs;uppo&longs;e. </s> <s>It may be ea&longs;ily reply'd, That <lb/>the pre&longs;&longs;ure of the inward Air again&longs;t the <lb/>Gla&longs;s, is countervail'd by the equal pre&longs;-<pb xlink:href="013/01/081.jpg" pagenum="41"/>&longs;ure of the outward again&longs;t the &longs;ame Gla&longs;s. <lb/></s> <s>And we &longs;ee in bubles, that by rea&longs;on of <lb/>this an exceeding thin film of Water is <lb/>often able, for a good while, to hinder the <lb/>eruption of a pretty quantity of Air. </s> <s>And <lb/>this may be al&longs;o more con&longs;picuous in <lb/>tho&longs;e great Spherical bubles that boyes <lb/>&longs;ometimes blow with Water, to which <lb/>Sope has given a Tenacity. </s> <s>But that, if the <lb/>pre&longs;&longs;ure of the ambient Air were remov'd, <lb/>the internal Air may be able to break <lb/>thicker Gla&longs;&longs;es then tho&longs;e lately men­<lb/>tion'd, will appear by &longs;ome of the follow­<lb/>ing Experiments; to which we &longs;hall there­<lb/>fore now ha&longs;ten, having, I fear, been but <lb/>too prolix in this Excur&longs;ion, though we <lb/>thought it not ami&longs;s to annex to our fir&longs;t <lb/>Experiments &longs;ome general Con&longs;iderati­<lb/>ons touching the Spring of the Air, be­<lb/>cau&longs;e (this Doctrine being yet a &longs;tranger <lb/>to the Schools) not onely we finde not <lb/>the thing it &longs;elf to be much taken notice <lb/>of; but of tho&longs;e few that have heard of it, <lb/>the greater part have been forward to re­<lb/>ject it, upon a mi&longs;taken Per&longs;wa&longs;ion, that <lb/>tho&longs;e <emph type="italics"/>Phænomena<emph.end type="italics"/> are the effects of natures <lb/>abhorrency of a <emph type="italics"/>Vacuum,<emph.end type="italics"/> which &longs;eem to <lb/>be more fitly a&longs;cribeable to the weight <lb/>and Spring of the Air. </s></p><pb xlink:href="013/01/082.jpg" pagenum="42"/><p type="main"> <s>WE will now proceed to ob&longs;erve that <lb/><arrow.to.target n="marg5"/><lb/>though, by the help of the handle, <lb/>the Sucker be ea&longs;ily drawn down to the <lb/>bottom of the Cylinder; yet, without <lb/>the help of that Leaver, there would be <lb/>required to the &longs;ame effect, a force or <lb/>weight great enough to &longs;urmount the <lb/>pre&longs;&longs;ure of the whole Atmo&longs;phere: Since <lb/>otherwi&longs;e the Air would not be driven out <lb/>of its place, when none is permitted to <lb/>&longs;ucceed into the place de&longs;erted by the <lb/>Sucker. </s> <s>This &longs;eems evident, from the <lb/>known <emph type="italics"/>Torricellian<emph.end type="italics"/> Experiment, in which, <lb/>if the inverted Tube of <emph type="italics"/>Mercury<emph.end type="italics"/> be but <lb/>25 Digits high, or &longs;omewhat more, the <lb/>Quick-&longs;ilver will not fall but remain &longs;u&longs;­<lb/>pended in the Tube; becau&longs;e it cannot <lb/>pre&longs;s the &longs;ubjacent <emph type="italics"/>Mercury<emph.end type="italics"/> with &longs;o great <lb/>a force, as does the incumbent Cylinder <lb/>of the Air reaching thence to the top of <lb/>the Atmo&longs;phere: Whereas, if the Cy­<lb/>linder of <emph type="italics"/>Mercury<emph.end type="italics"/> were three or four digits <lb/>longer, it would over-power that of the <lb/>external Air, and run out into the Ve&longs;&longs;el'd <lb/><emph type="italics"/>Mercury,<emph.end type="italics"/> till the two Cylinders came to <lb/>an <emph type="italics"/>Æquilibrium,<emph.end type="italics"/> and no further. </s> <s>Hence <lb/>we need not wonder, that though the <pb xlink:href="013/01/083.jpg" pagenum="43"/>Sucker move ea&longs;ily enough up and down <lb/>in the Cylinder by the help of the <emph type="italics"/>Manu­<lb/>brium;<emph.end type="italics"/> yet if the <emph type="italics"/>Manubrium<emph.end type="italics"/> be taken off, <lb/>it will require & con&longs;iderable &longs;trength to <lb/>move it either way. </s> <s>Nor will it &longs;eem <lb/>&longs;trange, that if, when the Valve and <lb/>Stop-cock are well &longs;hut, you draw down <lb/>the Sucker, and then let go the <emph type="italics"/>Manubri­<lb/>um;<emph.end type="italics"/> the Sucker will, as it were of it &longs;elf, <lb/>re-a&longs;cend to the top of the Cylinder, &longs;ince <lb/>the &longs;pring of the external Air findes no­<lb/>thing to re&longs;i&longs;t its pre&longs;&longs;ing up the Sucker. <lb/></s> <s>And for the &longs;ame rea&longs;on, when the Re­<lb/>ceiver is almo&longs;t evacuated, though, ha­<lb/>ving drawn down the Sucker, you open <lb/>the way from the Receiver to the Cylin­<lb/>der, and then intercept that way again by <lb/>returning the Key; the Sucker will, up­<lb/>on the letting go the <emph type="italics"/>Manubrium,<emph.end type="italics"/> be <lb/>forcibly carried up almo&longs;t to the top of <lb/>the Cylinder: Becau&longs;e the Air within the <lb/>Cylinder, being equally dilated and weak­<lb/>ned with that of the Gla&longs;s, is unable to <lb/>with&longs;tand the pre&longs;&longs;ure of the external Air, <lb/>till it be driven into &longs;o little &longs;pace, that <lb/>there is an <emph type="italics"/>Æquilibrium<emph.end type="italics"/> betwixt its force <lb/>and that of the Air without. </s> <s>And con­<lb/>gruou&longs;ly hereunto we finde, that in this <lb/>ca&longs;e, the Sucker is drawn down with little <pb xlink:href="013/01/084.jpg" pagenum="44"/>le&longs;s difficulty, then if the Cylinder, be­<lb/>ing devoid of Air, the Stop-cock were <lb/>exactly &longs;hut: We might take notice of <lb/>&longs;ome other things, that depend upon the <lb/>Fabrick of our Engine it &longs;elf; but to &longs;hun <lb/>prolixity, we will, in this place, content <lb/>our &longs;elves to mention one of them, which <lb/>&longs;eems to be of greater moment then the <lb/>re&longs;t, and it is this; that when the Sucker <lb/>has been impell'd to the top of the Cylin­<lb/>der, and the Valve is &longs;o carefully &longs;topp'd, <lb/>that there is no Air left in the Cylinder a­<lb/>bove the Sucker: If then the Sucker be <lb/>drawn to the lower part of the Cylinder, <lb/>he that manages the Pump findes not any <lb/>&longs;en&longs;ibly greater difficulty to depre&longs;s the <lb/>Sucker, when it is nearer the bottom of the <lb/>Cylinder, then when it is much further off. <lb/></s> <s>Which circum&longs;tance we therefore think fit <lb/>to take notice of, becau&longs;e an eminent Mo­<lb/>dern Naturali&longs;t hath taught, that, when the <lb/>Air is &longs;ucked out of a Body, the violence <lb/>wherewith it is wont to ru&longs;h into it again, <lb/>as &longs;oon as it is allow'd to re-enter, pro­<lb/>ceeds mainly from this; That the pre&longs;&longs;ure <lb/>of the ambient Air is &longs;trengthned upon <lb/>the acce&longs;&longs;ion of the Air &longs;uck'd out; which, <lb/>to make it &longs;elf room, forces the neighbor­<lb/>ing Air to a violent-&longs;ubingre&longs;&longs;ion o&longs; its <lb/>parts: which, i&longs; it were true, he that draws <pb xlink:href="013/01/085.jpg" pagenum="45"/>down the Sucker, would finde the re&longs;i&longs;t­<lb/>ance of the external Air increa&longs;'d as he <lb/>draws it lower, more of the di&longs;placed Air <lb/>being thru&longs;t into it to compre&longs;s it. </s> <s>But, by <lb/>what has been di&longs;cour&longs;'d upon the fir&longs;t <lb/>Experiment, it &longs;eems more probable, that <lb/>without any &longs;uch &longs;trengthning of the pre&longs;­<lb/>&longs;ure of the outward Air, the taking quite <lb/>away or the debilitating of the re&longs;i&longs;tance <lb/>from within, may &longs;uffice to produce the <lb/>effects under con&longs;ideration. </s> <s>But this will <lb/>perhaps be illu&longs;trated by &longs;ome or other of <lb/>our future Experiments, and therefore <lb/>&longs;hall be no longer in&longs;i&longs;ted on here. </s></p><p type="margin"> <s><margin.target id="marg5"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 3.</s></p><p type="main"> <s>HAving thus taken notice of &longs;ome of <lb/><arrow.to.target n="marg6"/><lb/>the con&longs;tant <emph type="italics"/>Phænomena<emph.end type="italics"/> of our En­<lb/>gine it &longs;elf, let us now proceed to the Ex­<lb/>periments tryable in it. </s></p><p type="margin"> <s><margin.target id="marg6"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 4.</s></p><p type="main"> <s>We took then a Lambs Bladder large, <lb/>well dry'd, and very limber, and leaving in <lb/>it about half as much Air as it could con­<lb/>tain, we cau&longs;'d the neck of it to be &longs;trong­<lb/>ly ty'd, &longs;o that none of the included Air, <lb/>though by pre&longs;&longs;ure, could get out. </s> <s>This <lb/>Bladder being convey'd into the Receiver, <lb/>and the Cover luted on, the Pump <lb/>was &longs;et awork, and after two or three <lb/>ex&longs;uctions of the ambient Air (where­<lb/>by the Spring of that which remain'd in <pb xlink:href="013/01/086.jpg" pagenum="46"/>the Gla&longs;s was weaken'd) the Impri&longs;on'd <lb/>Air began to &longs;well in the Bladder, and as <lb/>more and more of the Air in the Recei­<lb/>ver was, from time to time, drawn out; &longs;o <lb/>did that in the Bladder more and more ex­<lb/>pand it &longs;elf, and di&longs;play the folds of the <lb/>formerly flaccid Bladder: &longs;o that before we <lb/>had exhau&longs;ted the Receiver near &longs;o much <lb/>as we could, the Bladder appear'd as full <lb/>and &longs;tretched, as if it had been blown up <lb/>with a Quill. </s></p><p type="main"> <s>And that it may appear that this plump­<lb/>ne&longs;s of the Bladder proceeded from the <lb/>&longs;urmounting of the debilitated Spring of <lb/>the ambient Air remaining in the Ve&longs;&longs;el, <lb/>by the &longs;tronger Spring of the Air remain­<lb/>ing in the Bladder; we Return'd the Key <lb/>of the Stop-cock, and by degrees allow'd <lb/>the external Air to return into the Recei­<lb/>ver: Whereupon it happen'd, as was ex­<lb/>pected, that as the Air came in from with­<lb/>out, the di&longs;turb'd Air in the Bladder, was <lb/>proportionably compre&longs;&longs;'d into a narrow­<lb/>er room, and the &longs;ides of the Bladder <lb/>grew flaccid, till the Receiver having re­<lb/>admitted its wonted quantity of Air, the <lb/>Bladder appear'd as full of wrinkles and <lb/>cavities as before. </s></p><pb xlink:href="013/01/087.jpg" pagenum="47"/><p type="main"> <s>This Experiment is much of the &longs;ame <lb/>nature with that which was &longs;ome years <lb/>agoe &longs;aid to be made by that eminent Ge­<lb/>ometrician Mon&longs;ieur <emph type="italics"/>Roberval,<emph.end type="italics"/> with a <lb/>Carps Bladder empty'd and convey'd into <lb/>a Tube, wherein the Experiment <emph type="italics"/>De Va­<lb/>cuo<emph.end type="italics"/> was afterwards try'd, which ingeni­<lb/>ous Experiment of his ju&longs;tly de&longs;erves the <lb/>thanks of tho&longs;e that have been, or &longs;hall be <lb/>&longs;olicitous to di&longs;cover the nature of the <lb/>Air. </s></p><p type="main"> <s>But to return to our Experiment, we <lb/>may take notice of this Circum&longs;tance in <lb/>it, That after the Receiver has been in <lb/>&longs;ome mea&longs;ure empty'd, the Bladder do's, <lb/>at each ex&longs;uction, &longs;well much more con­<lb/>&longs;picuou&longs;ly then it did at any of the fir&longs;t <lb/>Ex&longs;uctions; in&longs;omuch that towards the <lb/>end of the pumping, not onely a great <lb/>fold or cavity in the &longs;urface of the Blad­<lb/>der may be made, even by the &longs;tretching <lb/>of the inward &longs;elf-expanding Air: But <lb/>we have &longs;ometimes &longs;een, upon the turn­<lb/>ing of the Key to let the ambient Air <lb/>pa&longs;s out of the Receiver into the Cylin­<lb/>der, we have &longs;een (I &longs;ay) the Air in the <lb/>Bladder &longs;uddenly expand it &longs;elf &longs;o much <lb/>and &longs;o briskly, that it manife&longs;tly lifted up <lb/>&longs;ome light Bodies that lean'd upon it, <pb xlink:href="013/01/088.jpg" pagenum="48"/>and &longs;eem'd to lift up the Bladder it <lb/>&longs;elf. </s></p><p type="main"> <s>Now becau&longs;e it has by very Learned <lb/>Men been doubted whether the &longs;welling <lb/>of the Bladder may not have proceeded <lb/>from the Dilatation of the included Air, <lb/>but from the Texture of the Fibres, <lb/>which, being wont to keep the Bladder <lb/>extended when the Animal to whom it <lb/>belong'd was alive, may be &longs;uppo&longs;'d in <lb/>our Experiment to have return'd, like &longs;o <lb/>many Springs to their wonted extent, up­<lb/>on the removal of the Ambient Air that <lb/>compre&longs;&longs;'d and bent them: becau&longs;e this, <lb/>I &longs;ay, has been doubted, we thought fit <lb/>to make this further tryall. </s></p><p type="main"> <s>We let down into the Receiver with <lb/>the fore-mentioned Bladder two other <lb/>much &longs;maller, and of the &longs;ame kinde of <lb/>Animal; the one of the&longs;e was not ty'd <lb/>up at the neck that there might be liberty <lb/>left to the Air that was not &longs;queez'd out <lb/>(which might amount to about a fifth <lb/>part of what the Bladder held before) to <lb/>pa&longs;s out into the Receiver: The other had <lb/>the &longs;ides of it &longs;tretch'd out and pre&longs;&longs;'d to­<lb/>gether, almo&longs;t into the form of a Cup, <lb/>that they might intercept the le&longs;s Air be­<lb/>twixt them, and then was &longs;trongly ty'd <pb xlink:href="013/01/089.jpg" pagenum="49"/>up at the neck: This done, and the Air <lb/>being in &longs;ome mea&longs;ure &longs;uck'd out of the <lb/>Pneumatical Gla&longs;s (if I may &longs;o call it) <lb/>the Bladder, mention'd at the beginning <lb/>of our Experiment, appear'd extended e­<lb/>very way to its full Dimen&longs;ions; whereas <lb/>neither of the two others did remarkably <lb/>&longs;well, and that who&longs;e neck was not ty'd <lb/>&longs;eem'd very little, if at all le&longs;s wrinkl'd <lb/>then when it was put in. </s></p><p type="main"> <s>We made likewi&longs;e a &longs;trong Ligature a­<lb/>bout the middle of a long Bladder part­<lb/>ly empty'd, and upon the drawing the <lb/>Air out of the Receiver, could ob&longs;erve <lb/>no &longs;uch &longs;welling betwixt the Ligature and <lb/>the Neck of the Bladder, which had been <lb/>purpo&longs;ely left open, as betwixt the &longs;ame <lb/>Ligature and the bottom of the Bladder, <lb/>whence the included Air could no way <lb/>get out. </s></p><p type="main"> <s>But a further and &longs;ufficient manife&longs;tati­<lb/>on whence the intume&longs;&longs;ence of the Blad­<lb/>der proceeds, may be deduc'd from the <lb/>following Experiment. </s></p><p type="main"> <s>TO try then at once both what it was <lb/><arrow.to.target n="marg7"/><lb/>that expanded the Bladder, and what <lb/>a powerful Spring there is ev'n in the Air <pb xlink:href="013/01/090.jpg" pagenum="50"/>we are wont to think uncompre&longs;&longs;'d, we <lb/>cau&longs;'d a Bladder dry, well ty'd and blown <lb/>moderately full, to be hung in the Recei­<lb/>ver by one end of a &longs;tring, who&longs;e other <lb/>end was fa&longs;tned to the in&longs;ide of the Co­<lb/>ver: and upon drawing out the ambient <lb/>Air, that pre&longs;&longs;'d on the Bladder; the in­<lb/>ternal Air not finding the wonted re&longs;i&longs;t­<lb/>ance, fir&longs;t &longs;well'd and di&longs;tended the Blad­<lb/>der, and then broke it, with &longs;o wide and <lb/>crooked a rent, as if it had been forcibly <lb/>torn a&longs;&longs;under with hands. </s> <s>After which a <lb/>&longs;econd Bladder being convey'd in, the Ex­<lb/>periment was repeated with like &longs;ucce&longs;s: <lb/>And I &longs;uppo&longs;e it will not be imagin'd that <lb/>in this ca&longs;e the Bladder was broken by its <lb/>own Fibres, rather then by the Impri­<lb/>&longs;on'd Air. </s></p><p type="margin"> <s><margin.target id="marg7"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 5.</s></p><p type="main"> <s>And of this Experiment the&longs;e two <emph type="italics"/>Phæ­<lb/>nomena<emph.end type="italics"/> may be taken notice of: The one, <lb/>that the Bladder at its breaking gave a <lb/>great report, almo&longs;t like a Craker: And <lb/>the other, That the Air contain'd in the <lb/>Bladder, had the power to break it with <lb/>the mention'd Impetuo&longs;ity, long before <lb/>the ambient Air was, all or near all, drawn <lb/>out of the Receiver. </s></p><p type="main"> <s>But, to verifie what we &longs;ay in another <lb/>Di&longs;cour&longs;e, where we &longs;how, That even <pb xlink:href="013/01/091.jpg" pagenum="51"/>true Experiments may, by rea&longs;on of <lb/>the ea&longs;ie mi&longs;take of &longs;ome unheeded <lb/>Circum&longs;tance, be un&longs;ucce&longs;sfully try'd; <lb/>we will Adverti&longs;e, on this occa&longs;ion, <lb/>that we did oftentimes in vain try the <lb/>breaking of Bladders, after the manner <lb/>above-mention'd: Of which the cau&longs;e <lb/>appear'd to be this, That the Bladders we <lb/>could not break, having been brought us <lb/>ready blown from tho&longs;e that &longs;old them, <lb/>were grown dry before they came to our <lb/>hands: whence it came to pa&longs;s, that, if <lb/>we afterwards ty'd them very hard, they <lb/>were apt to fret and &longs;o become un&longs;ervice­<lb/>able; and if we ty'd them but moderate­<lb/>ly hard, their &longs;tiffne&longs;s kept them from be­<lb/>ing clo&longs;'d &longs;o exactly, but that when the <lb/>included Air had in the exhau&longs;ted Recei­<lb/>ver di&longs;tended them as much as ea&longs;ily it <lb/>could, it would in part get out between <lb/>the little wrinkles of the Sphincter of the <lb/>Neck: Whence al&longs;o it u&longs;ually happen'd, <lb/>that, upon the letting in the Air from <lb/>without, the Bladders appear'd more flac­<lb/>cid and empty then before they were put <lb/>in; whereas when the Bladders were <lb/>brought us moi&longs;t from the Butchers, we <lb/>could, without injuring them, tye their <lb/>necks &longs;o clo&longs;e, that none of the Air once <pb xlink:href="013/01/092.jpg" pagenum="52"/>blown in, could get out of them, but by <lb/>violently breaking them. </s></p><p type="main"> <s>It will not be ami&longs;s on this occa&longs;ion to <lb/>point at &longs;omething which may de&longs;erve a <lb/>more deliberate Speculation then we can <lb/>now afford it; namely that the Ela&longs;tical <lb/>Power of the &longs;ame Quantity of Air may <lb/>be as well Encrea&longs;'d by the Agitation of <lb/>the Aërial Particles (whether onely mo­<lb/>ving them more &longs;wiftly and &longs;cattering <lb/>them, or al&longs;o extending or &longs;tretching <lb/>them out, I determine not) within an <lb/>every way inclo&longs;ing and yet yielding Bo­<lb/>dy; as Di&longs;play'd by the withdrawing of <lb/>the Air that pre&longs;&longs;'d it without. </s> <s>For we <lb/>found that a Bladder, but moderately <lb/>fill'd with Air and &longs;trongly ty'd, being <lb/>a while held near the Fire, not onely grew <lb/>exceeding turgid and hard, but after­<lb/>wards, being approach'd nearer to the <lb/>Fire, &longs;uddenly broke with &longs;o loud and ve­<lb/>hement a noi&longs;e, as &longs;tony'd tho&longs;e that were <lb/>by, and made us, for a while after, almo&longs;t <lb/>deaf. </s></p><p type="main"> <s>HAving thus &longs;een that the Air has an <lb/><arrow.to.target n="marg8"/><lb/>Ela&longs;tical Power, we were next de&longs;i­<lb/>rous to know in &longs;ome mea&longs;ure how far a <pb xlink:href="013/01/093.jpg" pagenum="53"/>parcel of Air might by this its own Spring <lb/>be dilated. </s> <s>And though we were not pro­<lb/>vided of In&longs;truments fit to mea&longs;ure the <lb/>dilatation of the Air any thing accurately, <lb/>yet becau&longs;e an imperfect mea&longs;ure of it was <lb/>more de&longs;ireable then none at all, we de­<lb/>vi&longs;'d the following Method as very ea&longs;ily <lb/>practicable. </s></p><p type="margin"> <s><margin.target id="marg8"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 6.</s></p><p type="main"> <s>We took a limber Lambs Bladder <lb/>which was thorowly wetted in fair Water, <lb/>that the &longs;ides of it being &longs;queez'd roge­<lb/>ther, there might be no Air left in its <lb/>folds: (as indeed we could not afterwards <lb/>upon tryal di&longs;cern any) The neck of this <lb/>Bladder was &longs;trongly tyed about that of <lb/>a &longs;mall Gla&longs;s, (capable of holding five <lb/>full drachmes of Water) the Bladder be­<lb/>ing fir&longs;t &longs;o compre&longs;&longs;'d, that all the inclu­<lb/>ded Air was onely in the Gla&longs;s, without <lb/>being pre&longs;&longs;'d there; then the Pump be­<lb/>ing &longs;et awork after a few ex&longs;uctions, the <lb/>Air in the little Viol began to dilate it <lb/>&longs;elf and produce a &longs;mall Tumor in the <lb/>Neck of the Bladder; and as the ambi­<lb/>ent Air was more and more drawn away, <lb/>&longs;o the included Air penetrated further and <lb/>further into the Bladder, and by degrees <lb/>lifted up the &longs;ides and di&longs;play'd its folds, <lb/>till at length it &longs;eem'd to have blown it <pb xlink:href="013/01/094.jpg" pagenum="54"/>up to its full extent: whereupon the ex­<lb/>ternal Air, being permitted to flow back <lb/>into the Reciver, repul&longs;'d the Air that <lb/>had fill'd the Bladder into its former nar­<lb/>row receptacle, and brought the Bladder <lb/>to be again flaccid and wrinkled as before: <lb/>Then taking out the Bladder, but with­<lb/>out &longs;evering it from the Gla&longs;s, we did by <lb/>a hole made at the top of the Bladder fill <lb/>the Ve&longs;&longs;el they both made up with Wa­<lb/>ter, who&longs;e weight was five Ounces five <lb/>Drachmes and an half: Five Drachmes <lb/>whereof were above-mention'd to be the <lb/>contents of the Bottle. </s> <s>So that in this Ex­<lb/>periment, when the Air had mo&longs;t extend­<lb/>ed the Bladder, it po&longs;&longs;e&longs;&longs;'d in all above <lb/>nine times as much room as it did when it <lb/>was put into the Receiver. </s> <s>And it would <lb/>probably have much inlarg'd its bounds, <lb/>but that the Bladder by its weight and the <lb/>&longs;ticking together of its &longs;ides did &longs;ome­<lb/>what re&longs;i&longs;t its expan&longs;ion: And which was <lb/>more con&longs;iderable, the Bladder appear'd <lb/>tumid enough, whil&longs;t yet a pretty deal of <lb/>Air was left in the Receiver, who&longs;e ex­<lb/>&longs;uction would, according to our former <lb/>Ob&longs;ervation, probably have given way <lb/>to a further expan&longs;ion of the Air, e&longs;peci-<pb xlink:href="013/01/095.jpg" pagenum="55"/>ally &longs;uppo&longs;ing the dilatation not to be re­<lb/>&longs;train'd by the Bladder. </s></p><p type="main"> <s>SInce we wrote the other day the former <lb/>Experiment, we have met with &longs;ome <lb/>Gla&longs;&longs;es not very unfit for our purpo&longs;e; <lb/>by means of which we are now able, with <lb/>a little more trouble, to mea&longs;ure the ex­<lb/>pan&longs;ion of the Air a great deal more ac­<lb/>curately then we could by the help of the <lb/>above-mention'd Bladder, which was <lb/>much to narrow to allow the Air its ut­<lb/>mo&longs;t di&longs;tention. </s></p><p type="main"> <s>We took then fir&longs;t a Cylindrical Pipe <lb/>of Gla&longs;s, who&longs;e bore was about a quarter <lb/>of an Inch in Diameter: this Pipe was &longs;o <lb/>bent and doubled, that, notwith&longs;tanding <lb/>its being about two foot in length, it <lb/>might have been &longs;hut up into a &longs;mall Re­<lb/>ceiver, not a Foot high: But by mi&longs;­<lb/>fortune it crack'd in the cooling, whereby <lb/>we were reduced to make u&longs;e of one part <lb/>which was &longs;traight and intire, but exceed­<lb/>ed not &longs;ix or &longs;even Inches. </s> <s>This little <lb/>Tube was open at one end; and at the <lb/>other, where it was Hermetically &longs;eal'd, <lb/>had a &longs;mall Gla&longs;s bubble to receive the <lb/>Air who&longs;e dilatation was to be mea&longs;ur'd. </s></p><pb xlink:href="013/01/096.jpg" pagenum="56"/><p type="main"> <s>Along the &longs;ide of this Tube was pa&longs;t­<lb/>ed a &longs;traight narrow piece of Parchment, <lb/>divided into twenty &longs;ix equal parts, mark­<lb/>ed with black Lines and Figures, that by <lb/>them might be mea&longs;ur'd both the inclu­<lb/>ded Air and its dilatation. </s> <s>Afterwards <lb/>we fill'd the Tube with Water almo&longs;t to <lb/>the top, and &longs;topping the open end with <lb/>a Finger, and inverting the Tube, the <lb/>Air was permitted to a&longs;cend to the above­<lb/>mention'd Gla&longs;s bubble. </s> <s>And by rea­<lb/>&longs;on this a&longs;cent was very &longs;low, it gave us <lb/>the opportunity to mark how much more <lb/>or le&longs;s then one of the twenty &longs;ix divi&longs;i­<lb/>ons this Air took up. </s> <s>By this means, af­<lb/>ter a tryal or two, we were inabled to con­<lb/>vey to the top of the Gla&longs;s a bubble of <lb/>Air equal enough, as to &longs;ight, to one <lb/>of tho&longs;e Divi&longs;ions: Then the open end <lb/>of the Tube being put into a &longs;mall Viol, <lb/>who&longs;e bottom was cover'd with Water <lb/>about half an Inch high; we included <lb/>both Gla&longs;&longs;es into a &longs;mall and &longs;lender Re­<lb/>ceiver, and cau&longs;ed the Pump to be &longs;et a­<lb/>work. </s> <s>The event was, That at the fir&longs;t <lb/>ex&longs;uction of the Air there appear'd not <lb/>any expan&longs;ion of the bubble, comparable <lb/>to what appear'd at the &longs;econd, and that <lb/>upon a very few ex&longs;uctions the bubble <pb xlink:href="013/01/097.jpg" pagenum="57"/>reaching as low as the &longs;urface of the &longs;ub­<lb/>jacent Water, gave us cau&longs;e to think <lb/>that if our Pipe had not been broken it <lb/>would have expanded it &longs;elf much fur­<lb/>ther: Wherefore we took out the little <lb/>Tube, and found that be&longs;ides the twenty <lb/>&longs;ix divi&longs;ions formerly mention'd, the <lb/>Gla&longs;s bubble and &longs;ome part of the Pipe <lb/>to which the divided Parchment did not <lb/>reach, amounted to &longs;ix divi&longs;ions more. <lb/></s> <s>Whereby it appears that the air had taken <lb/>up one and thirty times as much room as <lb/>before, and yet &longs;eem'd capable of a much <lb/>greater expan&longs;ion, if the Gla&longs;s would <lb/>have permitted it. </s> <s>Wherefore, after the <lb/>former manner, we let in another bubble, <lb/>that by our gue&longs;s was but half as big as <lb/>the former, and found, that upon the ex­<lb/>&longs;uction of the Air from the Receiver, this <lb/>little bubble did not onely fill up the <lb/>whole Tube, but (in part) break through <lb/>the &longs;ubjacent Water in the Viol, and <lb/>thereby manife&longs;t it &longs;elf to have po&longs;&longs;e&longs;&longs;ed <lb/>&longs;ixty and odde times its former room. </s></p><p type="main"> <s>The&longs;e two Experiments are mention'd <lb/>to make way for the more ea&longs;ie belief of <lb/>that which is now to follow. </s> <s>Finding <lb/>then that our Tube was too &longs;hort to &longs;erve <lb/>our turn, we took a &longs;lender Quill of Gla&longs;s <pb xlink:href="013/01/098.jpg" pagenum="58"/>which happen'd to be at hand, though it <lb/>were not &longs;o fit for our purpo&longs;e as we <lb/>could have wi&longs;hed, in regard it was three <lb/>or four times as big at one end as the o­<lb/>ther. </s> <s>This Pipe which was thirty Inches <lb/>long, being Hermetically &longs;eal'd at the <lb/>&longs;lender end, was almo&longs;t filled with Wa­<lb/>ter; and after the above-related manner <lb/>a bubble was convey'd to the top of it, <lb/>and the open extream was put into a Viol <lb/>that had a little fair Water at the bottom: <lb/>Then the Cover, by means of a &longs;mall hole <lb/>purpo&longs;ely made in it for the Gla&longs;s Pipe to <lb/>&longs;tand out at, was cemented on to the Re­<lb/>ceiver, and the Pump being &longs;et awork, <lb/>after &longs;ome ex&longs;uctions, not onely the Air <lb/>manife&longs;tly appear'd extended below the <lb/>&longs;urface of the &longs;ubjacent Water; but one <lb/>of the By-&longs;tanders affirms, that he &longs;aw <lb/>&longs;ome bubbles come out at the bottom of <lb/>the Pipe and break through the Water <lb/>This done, we left off Pumping, and ob­<lb/>&longs;erv'd how at the unperceiv'd leaks of the <lb/>Receiver the Air got in &longs;o fa&longs;t, thatit <lb/>very quickly impell'd up the Water to <lb/>the top of the Tube, excepting a little <lb/>&longs;pace whereinto that bubble was repul&longs;'d, <lb/>which had &longs;o lately po&longs;&longs;e&longs;&longs;'d the whole <lb/>Tube; this Air at the &longs;lender end ap-<pb xlink:href="013/01/099.jpg" pagenum="59"/>pear'd to be a Cylinder of 5/6 parts of an <lb/>Inch in length; but when the Pipe was <lb/>taken out and turn'd up&longs;ide down, it ap­<lb/>pear'd at the other end inferior in bulk to a <lb/>Pea. </s></p><p type="main"> <s>The&longs;e things being thus done we took <lb/>(to make the Experiment the more ex­<lb/>actly) a &longs;mall pair of Scales, &longs;uch as Gold­<lb/>Smiths u&longs;e to weigh Gold Coyn in; and <lb/>weighing the Tube and Water in it, we <lb/>found them to amount to one Ounce thir­<lb/>ty Grains and an half: Then we pour'd in <lb/>as much Water as &longs;erv'd to fill up the <lb/>Tube, wherein before we had left as much <lb/>&longs;pace unfill'd up as was po&longs;&longs;e&longs;&longs;'d by the <lb/>bubble; and weighing again the Pipe and <lb/>Water, we found the weight increa&longs;'d <lb/>onely by one Grain. </s> <s>La&longs;tly, pouring out <lb/>the Water, and carefully freeing the Pipe <lb/>from it (which yet we could not perfectly <lb/>doe) we weighed the Gla&longs;s alone, and <lb/>found it to want two Drachmes and thirty <lb/>two Grains of its former weight: So <lb/>that the bubble of Air taking up the room <lb/>but of one Grain in weight of Water, it <lb/>appear'd that the Air by its own <foreign lang="greek">e)lith\r</foreign><lb/>was &longs;o rarified, as to take up one hundred <lb/>fifty two times as much room as it did be­<lb/>fore: though it were then compre&longs;&longs;'d by <pb xlink:href="013/01/100.jpg" pagenum="60"/>nothing but the ordinary pre&longs;&longs;ure of the <lb/>contiguous Air. </s> <s>I know not whether it <lb/>be requi&longs;ite to take notice, that this Ex­<lb/>periment was made indeed in a moi&longs;t <lb/>Night, but in a Room, in who&longs;e Chim­<lb/>ney there was burning a good Fire, which <lb/>did perhaps &longs;omewhat rarifie the Air of <lb/>which the bubble con&longs;i&longs;ted. </s></p><p type="main"> <s>It has &longs;eem'd almo&longs;t incredible which is <lb/>related by the Indu&longs;trious <emph type="italics"/>Mer&longs;ennus,<emph.end type="italics"/> That <lb/>the Air by the violence of heat, though <lb/>as great as our Ve&longs;&longs;els can &longs;upport with­<lb/>out fu&longs;ion, can be &longs;o dilated as to take up <lb/>&longs;eventy times as much room as before: <lb/>Wherefore becau&longs;e we were willing to <lb/>have a confirmation of &longs;o &longs;trange a <emph type="italics"/>Phæno­<lb/>menon;<emph.end type="italics"/> we once more convey'd into the <lb/>Tube a bubble of the bigne&longs;s of the for­<lb/>mer, and pro&longs;ecuting the Experiment as <lb/>before with the &longs;ame Water, we ob&longs;erved <lb/>that the Air did manife&longs;tly &longs;tretch it &longs;elf <lb/>&longs;o far, as to appear &longs;everal times a good <lb/>way below the &longs;urface of the Water in the <lb/>Viol, and that too with a &longs;urface very <lb/>convex toward the bottom of the Pipe. <lb/></s> <s>Nay, the Pump being ply'd a little lon­<lb/>ger, the Air did manife&longs;tly reach to that <lb/>place where the bottom of the Tube <lb/>lean'd upon the bottom of the Viol, and <pb xlink:href="013/01/101.jpg" pagenum="61"/>&longs;eem'd to knock upon it and rebound <lb/>from it: Which Circum&longs;tances we adde, <lb/>partly that the <emph type="italics"/>Phænomenon<emph.end type="italics"/> we have been <lb/>relating may not be imputed to the <lb/>bare &longs;ub&longs;iding of the Water that fill'd <lb/>the Tube, upon the taking off the pre&longs;­<lb/>&longs;ure of the ambient Air. </s> <s>And partly al­<lb/>&longs;o that it may appear that if our Expe­<lb/>riments have not been as accurately made <lb/>as with fitter In&longs;truments might perhaps <lb/>be po&longs;&longs;ible; yet the expan&longs;ion of the <lb/>Air is likely to be rather greater then <lb/>le&longs;&longs;er then we have made it: Since the <lb/>Air was able to pre&longs;s away the Water at <lb/>the bottom of the Pipe, though that were <lb/>about two Inches below the &longs;urface of the <lb/>Water that was then in the Viol, and <lb/>would have been at lea&longs;t as high in the <lb/>Pipe, if the Water had onely &longs;ub&longs;ided and <lb/>not been depre&longs;&longs;ed: So that it &longs;eems not <lb/>unlikely that if the Experiment could be <lb/>&longs;o made, as that the expan&longs;ion of the Air <lb/>might not be re&longs;i&longs;ted by the Neighboring <lb/>Bodies, it would yet inlarge its bounds, <lb/>and perhaps &longs;tretch it &longs;elf to two hundred <lb/>times its former bulk, if not more. </s> <s>How­<lb/>ever, what we have now try'd will, I hope, <lb/>&longs;uffice to hinder divers of the <emph type="italics"/>Phænomena<emph.end type="italics"/><lb/>of our Engine from being di&longs;tru&longs;ted: <pb xlink:href="013/01/102.jpg" pagenum="62"/>Since in that part of the Atmo&longs;phere we <lb/>live in, that which we call the free Air (and <lb/>pre&longs;ume to be &longs;o uncompre&longs;&longs;'d) is crouded <lb/>into &longs;o very &longs;mall a part of that &longs;pace, <lb/>which if it were not hindred it would po&longs;­<lb/>&longs;e&longs;s. </s> <s>We would gladly have tryed al&longs;o <lb/>whether the Air at its greate&longs;t expan&longs;ion <lb/>could be further rarified by heat; but do <lb/>what we could, our Receiver leak'd too <lb/>fa&longs;t to let us give our &longs;elves any &longs;atisfacti­<lb/>on in that particular. </s></p><p type="main"> <s>TO di&longs;cover likewi&longs;e by the means of <lb/><arrow.to.target n="marg9"/><lb/>that pre&longs;&longs;ure of the Air, both the <lb/>&longs;trength of Gla&longs;s, and how much inte­<lb/>re&longs;t the Figure of a Body may have in its <lb/>greater or le&longs;&longs;er Re&longs;i&longs;tance to the pre&longs;&longs;ure <lb/>of other Bodys, we made the&longs;e further <lb/>tryals. </s></p><p type="margin"> <s><margin.target id="marg9"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 7.</s></p><p type="main"> <s>We cau&longs;'d to be blown with a Lamp a <lb/>round Gla&longs;s bubble, capable of contain­<lb/>ing, by gue&longs;s, about five Ounces of Wa­<lb/>ter, with a &longs;lender neck about the bigne&longs;s <lb/>of a Swans Quill, and it was purpo&longs;ely <lb/>blown very thin, as Viols made with <lb/>Lamps are wont to be, that the thinne&longs;s <lb/>of the matter might keep the roundne&longs;s <lb/>of the Figure from making the Ve&longs;&longs;el too <pb xlink:href="013/01/103.jpg" pagenum="63"/>&longs;trong. </s> <s>Then having moderately empty­<lb/>ed the Receiver, and taken it out of the <lb/>Pump, we &longs;peedily applyed to the Ori­<lb/>fice of the bottom of it the Neck of the <lb/>newly mention'd Gla&longs;s, carefully &longs;topping <lb/>the Crannys with melted Plai&longs;ter, that no <lb/>Air might get in at them: And after <lb/>turning the Key of the Stop-cock, we <lb/>made a free pa&longs;&longs;age for the Air to pa&longs;s out <lb/>of the bubble into the Receiver: which it <lb/>did with great celerity, leaving the bub­<lb/>ble as empty as the Receiver it &longs;elf; as ap­<lb/>pear'd to us by &longs;ome Circum&longs;tances not <lb/>now to be in&longs;i&longs;ted on. </s> <s>Notwith&longs;tanding <lb/>all which, the Ve&longs;&longs;el, continuing as intire <lb/>as before, gave us cau&longs;e to wonder that <lb/>the bare Roundne&longs;s of the Figure &longs;hould <lb/>inable a Gla&longs;s, almo&longs;t as thin as Paper, to <lb/>re&longs;i&longs;t &longs;o great a pre&longs;&longs;ure as that of the <lb/>whole incumbent Atmo&longs;phere. </s> <s>And ha­<lb/>ving reiterated the Experiment, we found <lb/>again that the pre&longs;&longs;ure of the ambient <lb/>Body, thru&longs;ting all the parts inwards, <lb/>made them, by rea&longs;on of their arched Fi­<lb/>gure, &longs;o &longs;upport one another, that the <lb/>Gla&longs;s remain'd as whole as at fir&longs;t. </s></p><p type="main"> <s>Now that the Figure of the Gla&longs;s is <lb/>of great moment in this matter, may be <lb/>evinced by this other Experiment. </s></p><pb xlink:href="013/01/104.jpg" pagenum="64"/><p type="main"> <s>WE took a Gla&longs;s Helmet or Alem­<lb/><arrow.to.target n="marg10"/><lb/>bick (delineated by the &longs;eventh <lb/>Figure) &longs;uch as Chymi&longs;ts u&longs;e in Di&longs;tilla­<lb/>tions, and containing by conjecture be­<lb/>tween two and three Pints: The <emph type="italics"/>Ro&longs;trum<emph.end type="italics"/><lb/>or No&longs;e of it mark'd with <emph type="italics"/>(c)<emph.end type="italics"/> was Herme­<lb/>tically clo&longs;ed; and at the top of it was a <lb/>hole, into which was fitted and cemented <lb/>one of the Shanks of a middle-&longs;iz'd Stop­<lb/>cock; &longs;o that the Gla&longs;s being turn'd up­<lb/>&longs;ide-down, the wide Orifice (which in <lb/>common Gla&longs;s-Helmets is the onely one) <lb/>was upwards; and to that wide Orifice <lb/>was fitted a ca&longs;t-Cover of Lead, which <lb/>was carefully cemented on to the Gla&longs;s: <lb/>Then the other Shank of the Stop-cock <lb/>being with Cement likewi&longs;e fa&longs;ten'd into <lb/>the upper part of the Pump, the ex&longs;ucti­<lb/>on of the Air was endeavoured. </s> <s>But it <lb/>was not long before, the remaining Air <lb/>being made much too weak to ballance <lb/>the pre&longs;&longs;ure of the ambient Air, the Gla&longs;s <lb/>was not without a great noi&longs;e crack'd al­<lb/>mo&longs;t half round, along that part of it <lb/>where it began to bend inwards: As if <lb/>in the Figure the crack had been made ac­<lb/>cording to the Line <emph type="italics"/>(ab);<emph.end type="italics"/> and upon an <pb xlink:href="013/01/105.jpg" pagenum="65"/>endeavour to pump out more of the Air, <lb/>the crack once began, appear'd to run on <lb/>further; though the Gla&longs;s where it was <lb/>broken &longs;eem'd to be by conjecture above <lb/>ten, &longs;ome thought above twenty times as <lb/>thick as the bubble mention'd in the fore­<lb/>going Experiment. </s></p><p type="margin"> <s><margin.target id="marg10"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 8.</s></p><p type="main"> <s>This will perhaps make it &longs;eem &longs;trange, <lb/>that having taken another Gla&longs;s bubble <lb/>blown at the &longs;ame time, and like for <lb/>ought we di&longs;cern'd for &longs;ize, thickne&longs;s <lb/>and Figure to that thin one formerly <lb/>mention'd; and having &longs;eal'd it up Her­<lb/>metically, and &longs;u&longs;pended it in the Recei­<lb/>ver, the ex&longs;uction of the ambient Air did <lb/>not enable the impri&longs;oned Air to break, or <lb/>in the lea&longs;t to crack the bubble; though <lb/>the Experiment were laboriou&longs;ly try'd, <lb/>and that &longs;everal times with bubbles of o­<lb/>ther &longs;izes: But that perhaps the heat of <lb/>the Candle or Lamp wherewith &longs;uch <lb/>Gla&longs;&longs;es are Hermetically &longs;eal'd, (not to <lb/>mention the warmth of his hands that <lb/>&longs;eal'd it) might &longs;o rarifie the contained <lb/>Air, as much to weaken its Spring, may <lb/>&longs;eem probable by the following Expe­<lb/>riments. </s></p><pb xlink:href="013/01/106.jpg" pagenum="66"/><p type="main"> <s>WE took a Gla&longs;s Viol able to hold <lb/><arrow.to.target n="marg11"/><lb/>three or four Ounces of Water, <lb/>and of the thickne&longs;s u&longs;ual in Gla&longs;&longs;es of <lb/>that &longs;ize; into the Neck of this was put <lb/>a moderately &longs;lender Pipe of Gla&longs;s, which <lb/>was carefully fa&longs;ten'd with a mixture of e­<lb/>qual parts of Pitch and Ro&longs;in to the Neck <lb/>of the Viol, and which reach'd almo&longs;t to <lb/>the bottom of it, as the &longs;ixth Figure de­<lb/>clares. </s></p><p type="margin"> <s><margin.target id="marg11"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 9.</s></p><p type="main"> <s>This Viol being upon a particular de­<lb/>&longs;ign fill'd with Water, till that came up in <lb/>it a pretty deal higher then the lower end <lb/>of the Pipe, was put into one of our &longs;mall <lb/>Receivers, (containing between a Pint <lb/>and a Quart) in &longs;uch manner as that the <lb/>Gla&longs;s Pipe, pa&longs;&longs;ing through a hole made <lb/>purpo&longs;ely for it in the Leaden-Cover of <lb/>the Receiver, was for the mo&longs;t part of it <lb/>without the Ve&longs;&longs;el, which being exactly <lb/>clo&longs;ed, the Pump was &longs;et awork: But at <lb/>the very fir&longs;t ex&longs;uction, and before the <lb/>Sucker was drawn to the bottom of the <lb/>Cylinder, there flew out of the Viol a <lb/>piece of Gla&longs;s half as broad as the Palm <lb/>of a Mans Hand, and it was thrown out <lb/>with &longs;uch violence, that hitting again&longs;t <pb xlink:href="013/01/107.jpg" pagenum="67"/>the Neighboring &longs;ide of the Receiver, it <lb/>not onely dafh'd it &longs;elf to pieces, but <lb/>crack'd the very Receiver in many places, <lb/>with a great noi&longs;e that much &longs;urpri&longs;ed all <lb/>that were in the Room. </s> <s>But it &longs;eem'd <lb/>that in &longs;o little a Receiver, the Air about <lb/>the Viol being &longs;uddenly drawn out, the <lb/>Air Impri&longs;on'd in the Ve&longs;&longs;el, having on <lb/>it the whole pre&longs;&longs;ure of the Atmo&longs;phere <lb/>(to which by the Pipe open at both ends, <lb/>It and the Water were expo&longs;'d) and not <lb/>having on the other &longs;ide the wonted pre&longs;­<lb/>&longs;ure of the Ambient Air to ballance that <lb/>other pre&longs;&longs;ure, the re&longs;i&longs;tance of the Gla&longs;s <lb/>was finally &longs;urmounted, and the Viol once <lb/>beginning to break where it was weake&longs;t, <lb/>the external Air might ru&longs;h in with vio­<lb/>lence enough to throw the crack'd parcel <lb/>&longs;o forcibly again&longs;t the Neighboring &longs;ide <lb/>of the Receiver, as to break that too. </s></p><p type="main"> <s>And this may be pre&longs;umed &longs;ufficient to <lb/>verifie what we delivered in that part of <lb/>our Appendix to the fir&longs;t Experiment, <lb/>where we mention'd the almo&longs;t equal <lb/>pre&longs;&longs;ure of the Air on either &longs;ide of a <lb/>thin Gla&longs;s Ve&longs;&longs;el, as the cau&longs;e of its not <lb/>being broken by the forcible Spring of <lb/>the contain'd Air. </s> <s>But yet that it be not <lb/>&longs;u&longs;pected that chance had an intere&longs;t in &longs;o <pb xlink:href="013/01/108.jpg" pagenum="68"/>odde an Experiment as we have been Re­<lb/>lating, we will adde that for farther &longs;ati&longs;­<lb/>faction we reiterated it in a round Gla&longs;&longs;e <lb/>containing by gue&longs;&longs;e about &longs;ix ounces <lb/>of water: this violl we put into &longs;uch a <lb/>&longs;mall Receiver as was lately mention'd, <lb/>in &longs;uch manner as that the bottome of <lb/>it re&longs;ted upon the lower part of the Pneu­<lb/>maticall Gla&longs;&longs;e, and the Neck came out <lb/>through the Leaden-Cover of the &longs;ame <lb/>at a hole made purpo&longs;ely for it. </s> <s>But be­<lb/>ing made circum&longs;pect by the foregoing <lb/>mi&longs;chance, we had put the violl into a <lb/>Bladder, before we put it into the Re­<lb/>ceiver to hinder this la&longs;t named Gla&longs;&longs;e <lb/>from being endanger'd by the breaking <lb/>of the other. </s> <s>Then the Pneumaticall <lb/>ve&longs;&longs;ell being clos'd &longs;o that no way was <lb/>left for the outward Air to get into it, <lb/>but by breaking through the Viol, into <lb/>who&longs;e cavity it had free acce&longs;&longs;e by the <lb/>mouth of it, (which was purpo&longs;ely left <lb/>open,) the Sucker being nimbly drawn <lb/>down, the external Air immediatly pre&longs;&longs;'d <lb/>forcibly as well upon the Leaden-Co­<lb/>ver as the Violl; and the Cover hap­<lb/>pening to be in one place a little narrow­<lb/>er then the edge of the Pneumatical Gla&longs;s, <lb/>was depre&longs;&longs;'d, and thru&longs;t into it &longs;o vio-<pb xlink:href="013/01/109.jpg" pagenum="69"/>lently by the incumbent Air, that get­<lb/>ting a little within the tapering Lip of the <lb/>Gla&longs;s, it did like a kinde of Wedge, thru&longs;t <lb/>out that &longs;ide where it was depre&longs;&longs;'d, &longs;o as, <lb/>though the Receiver was new, to &longs;plit it. <lb/></s> <s>This accident being thus mention'd upon <lb/>the by to confirm what we formerly &longs;aid <lb/>touching the fitne&longs;s or unfitne&longs;s of Gla&longs;&longs;es <lb/>of &longs;ome Figures to re&longs;i&longs;t the pre&longs;&longs;ure of <lb/>the Atmo&longs;phere; We will proceed to <lb/>relate the remaining part of the Experi­<lb/>ment, namely, That having fitted on a <lb/>wider Cover to the &longs;ame Receiver, and <lb/>clo&longs;ed both that and the crack with Ce­<lb/>ment, we pro&longs;ecuted the Experiment in <lb/>the manner above related, with this &longs;uc­<lb/>ce&longs;s: That upon the quick depre&longs;&longs;ing of <lb/>the Sucker, the external Air bur&longs;t the <lb/>Body of the Viol in above a hundred pie­<lb/>ces, many of them exceeding &longs;mall, and <lb/>that with &longs;uch violence that we found a <lb/>wide rent, be&longs;ides many holes, made in <lb/>the Bladder it &longs;elf. </s></p><p type="main"> <s>And to evince that the&longs;e <emph type="italics"/>Phænomena<emph.end type="italics"/><lb/>were the effects of a limited and even <lb/>moderate force, and not of &longs;uch an ab­<lb/>horrency of a <emph type="italics"/>Vacuum<emph.end type="italics"/> as that to avoid it, <lb/>many have been plea&longs;ed to think that Na­<lb/>ture mu&longs;t, upon occa&longs;ion, exerci&longs;e an al-<pb xlink:href="013/01/110.jpg" pagenum="70"/>mo&longs;t boundle&longs;s power; we afterwards pur­<lb/>po&longs;ely try'd this Experiment with &longs;everal <lb/>Gla&longs;&longs;es &longs;omewhat thicker then tho&longs;e Vi­<lb/>ols, and found the event to verifie our con­<lb/>jecture, that it would not &longs;ucceed: for <lb/>the Gla&longs;&longs;es were taken out as intire as they <lb/>were put in. </s></p><p type="main"> <s>And here, My Lord, I hold it not un­<lb/>fit, upon occa&longs;ion of the mention that <lb/>has been made of our having employ'd <lb/>&longs;mall Receivers, and one of them, not­<lb/>with&longs;tanding its being crack'd, to annex <lb/>the&longs;e two Adverti&longs;ements. </s></p><p type="main"> <s>Fir&longs;t then, be&longs;ides the great Pneuma­<lb/>tical Gla&longs;s &longs;o often mention'd, and the <lb/>proportionate Stop-cock, we thought fit <lb/>to provide our &longs;elves of &longs;ome &longs;mall Recei­<lb/>vers blown of Cry&longs;talline Gla&longs;s, of &longs;eve­<lb/>rall Shapes, and furni&longs;hed with &longs;maller <lb/>Stop-cocks purpo&longs;ely made; and this we <lb/>did upon hopes that when we had &longs;ur­<lb/>mounted the difficulties to be met with in <lb/>Cementing the Gla&longs;&longs;es to the Stop­<lb/>cocks, and the Pneumatical Ve&longs;&longs;els to the <lb/>Pump &longs;o exqui&longs;itely as is requi&longs;ite for our <lb/>purpo&longs;e, we &longs;hould from the &longs;malne&longs;s of <lb/>our Receivers receive a four-fold Advan­<lb/>tage. </s> <s>The fir&longs;t, that by rea&longs;on of the <lb/>&longs;lenderne&longs;s of the Ve&longs;&longs;els, and their be-<pb xlink:href="013/01/111.jpg" pagenum="71"/>ing made of much purer and clearer me­<lb/>tall, as the Gla&longs;s-men &longs;peak, then the <lb/>great Receiver, we might have a more <lb/>perfect view of every thing happening <lb/>within them. </s> <s>The next, that &longs;uch &longs;mall <lb/>Ve&longs;&longs;els might be empty'd with le&longs;s la­<lb/>bour and in much le&longs;&longs;e time. </s> <s>The third, <lb/>that this nimble ex&longs;uction of the ambient <lb/>Air would make many changes in the <lb/>Bodies &longs;hut up in the&longs;e gla&longs;&longs;es more &longs;ud­<lb/>den and con&longs;picuous then otherwi&longs;e they <lb/>would prove. </s> <s>And the la&longs;t, that we &longs;hould <lb/>be able to draw and keep out the Air much <lb/>more perfectly from &longs;uch &longs;mall Ve&longs;&longs;els <lb/>then from our large Receiver. </s> <s>But though <lb/>we were not much di&longs;-appointed in the <lb/>expectation of the three fir&longs;t advantages, <lb/>yet we were in our hopes of the fourth. <lb/></s> <s>For be&longs;ides the great difficulty we found <lb/>in fitting together the Gla&longs;&longs;es, the Stop­<lb/>cocks and the Covers; be&longs;ides this I &longs;ay, <lb/>we found our &longs;elves &longs;eldom able to draw, <lb/>and keep out the Air &longs;o far as to make the <lb/>remaining Air in the&longs;e Receivers weaker <lb/>then the remaining Air in our great Recei­<lb/>ver. </s> <s>For though &longs;ometimes the Leaks <lb/>of &longs;ome of the&longs;e little Receivers may be <lb/>much either fewer or &longs;maller then tho&longs;e <lb/>of the larger Ve&longs;&longs;el; yet a little Air get-<pb xlink:href="013/01/112.jpg" pagenum="72"/>ting into one of the&longs;e, wherein it had but <lb/>little room to expand and di&longs;play it &longs;elf, <lb/>might pre&longs;s as much upon all parts of the <lb/>internal &longs;urface of the Ve&longs;&longs;el, and upon <lb/>the included Bodies, as a greater quan­<lb/>tity of Air in a Ve&longs;&longs;el in who&longs;e capacity <lb/>it might finde more room to expand it <lb/>&longs;elf. </s></p><p type="main"> <s>The other thing that we were to ad­<lb/>verti&longs;e, is, That 'tis not every &longs;mall crack <lb/>that can make &longs;uch a Receiver as is of a <lb/>roundi&longs;h Figure altogether u&longs;ele&longs;s to our <lb/>Experiment, in regard that upon the ex­<lb/>&longs;uction of the internal Air, the ambient <lb/>Air on all &longs;ides pre&longs;&longs;ing the Gla&longs;s inwards <lb/>or towards the middle, does con&longs;equent­<lb/>ly thru&longs;t the Lips of the crack clo&longs;er, and <lb/>&longs;o rather clo&longs;e then increa&longs;e it. </s></p><p type="main"> <s>This I mention partly becau&longs;e Recei­<lb/>vers fit for our turn are more ea&longs;ily <lb/>crack'd then procur'd, and therefore ought <lb/>not to be unnece&longs;&longs;arily thrown away as <lb/>un&longs;erviceable: And partly becau&longs;e I think <lb/>it becomes one that profe&longs;&longs;es him&longs;elf a <lb/>faithful Relator of Experiments, not to <lb/>conceal from Your Lord&longs;hip, that after a <lb/>few of the foregoing Experiments were <lb/>made, there happen'd in the great Recei­<lb/>ver a crack of about a Span long, begin-<pb xlink:href="013/01/113.jpg" pagenum="73"/>ning at the upper Orifice, and occa&longs;ion'd, <lb/>as it &longs;eem'd, by the exce&longs;&longs;ive heat of too <lb/>large an Iron that was employ'd to melt <lb/>the Cement about that Orifice. </s> <s>But ha­<lb/>ving laid upon this crack a broad Plai&longs;ter, <lb/>which in one of our E&longs;&longs;ays written &longs;ome <lb/>years &longs;ince to your ingenious and hopeful <lb/>Cou&longs;in <emph type="italics"/>Fones,<emph.end type="italics"/> we extoll for the mending <lb/>of crack'd Receivers, and other Chymi­<lb/>cal Gla&longs;&longs;es; and having afterwards thick­<lb/>ly over-laid this Plai&longs;ter with Diachylon, <lb/>we neither could then, nor can yet per­<lb/>ceive that the Ve&longs;&longs;el leaks &longs;en&longs;ibly at that <lb/>crack. </s></p><p type="main"> <s>The Plai&longs;ter was made of good quick <lb/>Lime finely poudred, and nimbly ground <lb/>with a Pe&longs;tle in a Morter, with a quantity <lb/>(I know not how much preci&longs;ely, not ha­<lb/>ving tho&longs;e E&longs;&longs;ays in this place) of &longs;cra­<lb/>pings of Chee&longs;e and a little fair Water, <lb/>no more then is ju&longs;t nece&longs;&longs;ary to bring the <lb/>mixture to a &longs;omewhat &longs;oft Pa&longs;te, which <lb/>when the Ingredients are exqui&longs;itely in­<lb/>corporated, will have a &longs;trong and <lb/>&longs;tincking &longs;mell: Then it mu&longs;t be im­<lb/>mediately &longs;pread upon a Linnen Cloath <lb/>three or four fingers breadth, and pre&longs;ently <lb/>apply'd, le&longs;t it begin to harden. </s> <s>But if <lb/>Your Lord&longs;hip had &longs;een how we mended <pb xlink:href="013/01/114.jpg" pagenum="74"/>with it Receivers even for the mo&longs;t &longs;ub­<lb/>tle Chymical Spirits, You would &longs;carce <lb/>wonder at the &longs;ervice it has done in our <lb/>Pneumatical Gla&longs;s. </s></p><p type="main"> <s>WE took a Tallow-Candle of &longs;uch <lb/><arrow.to.target n="marg12"/><lb/>a &longs;ize that eight of them make <lb/>about a pound, and having in a very com­<lb/>modious Candle&longs;tick let it down into the <lb/>Receiver, and &longs;o &longs;u&longs;pended it that the <lb/>Flame burnt almo&longs;t in the middle of the <lb/>Ve&longs;&longs;el, we did in &longs;ome two minutes ex­<lb/>actly clo&longs;e it up: and, upon Pumping ve­<lb/>ry nimbly, we found that within little <lb/>more then half a minute after the Flame <lb/>went out, though the Snuff had been <lb/>purpo&longs;ely left of that length we judged <lb/>the mo&longs;t convenient for the la&longs;ting of <lb/>the Flame. </s></p><p type="margin"> <s><margin.target id="marg12"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 10.</s></p><p type="main"> <s>But the &longs;econd time having put in the <lb/>&longs;ame Candle into the Receiver, (after it <lb/>had by the bla&longs;ts of a pair of Bellows <lb/>been freed from Fumes) the Flame la&longs;ted <lb/>about two minutes from the time the <lb/>Pumper began to draw out the Air; up­<lb/>on the fir&longs;t ex&longs;uction whereof, the Flame <lb/>&longs;eem'd to contract it &longs;elf in all its Dimen­<lb/>&longs;ions. </s> <s>And the&longs;e things were further ob-<pb xlink:href="013/01/115.jpg" pagenum="75"/>&longs;ervable, that after the two or three fir&longs;t <lb/>ex&longs;uctions of the Air, the Flame (except <lb/>at the very top) appear'd exceeding blew, <lb/>and that the Flame &longs;till receded more and <lb/>more from the Tallow, till at length it <lb/>appear'd to po&longs;&longs;e&longs;s onely the very top of <lb/>the Week, and there it went out. </s></p><p type="main"> <s>The &longs;ame Candle being lighted again <lb/>was &longs;hut into the Receiver, to try how it <lb/>would la&longs;t there without drawing forth <lb/>the Air, and we found that it la&longs;ted much <lb/>longer then formerly; and before it went <lb/>out receded from the Tallow towards the <lb/>the top of the Week, but not near &longs;o <lb/>much as in the former Experiment. </s></p><p type="main"> <s>And having an intention to ob&longs;erve par­<lb/>ticularly what the motion of the &longs;moak <lb/>would be in the&longs;e Experiments: We <lb/>took notice that when the Air was not <lb/>drawn out, there did upon the extinction <lb/>of the Flame a con&longs;iderable part of the <lb/>Week remain kindled, which (probably <lb/>by rea&longs;on of the Circulation of the Air <lb/>in the Ve&longs;&longs;el, occa&longs;ion'd by the heat) e­<lb/>mitted a Steam, which a&longs;cended &longs;wiftly <lb/>and directly upwards in a &longs;lender and unin­<lb/>terrupted Cylinder of &longs;moke, till it came <lb/>to the top, whence it manife&longs;tly recoyl'd <lb/>by the &longs;ides to the lower part of the Ve&longs;-<pb xlink:href="013/01/116.jpg" pagenum="76"/>&longs;el. </s> <s>Whereas when the Flame went out <lb/>upon the ex&longs;uction of the Air one time <lb/>(when the Flame retir'd very lea&longs;urely <lb/>to the top) we perceived it not to be fol­<lb/>low'd by any &longs;moke at all. </s> <s>And at an <lb/>other time the upper part of the Week <lb/>remaining kindled after the extinction <lb/>of the Flame, the &longs;lender &longs;team of Fumes <lb/>that did ari&longs;e a&longs;cended but a very little <lb/>way, and then after &longs;ome uncertain mo­<lb/>tions this and that way, did, for the mo&longs;t <lb/>part, &longs;oon fall downwards. </s></p><p type="main"> <s>Being de&longs;irous al&longs;o to try whether <lb/>there would be any difference as well in <lb/>our Receiver as there is wont to be el&longs;e­<lb/>where betwixt Candles made of Wax and <lb/>tho&longs;e made of Tallow, as to their dura­<lb/>tion; we took &longs;lender Tapers of white <lb/>Wax, (commonly called Virgins Wax) <lb/>that being found to burn with much le&longs;s <lb/>&longs;moke then common yellow Wax: Six <lb/>of the&longs;e of like bigne&longs;s, and each of them <lb/>of about the thickne&longs;s of a Swans Quill, <lb/>we pre&longs;&longs;'d together into one Candle: And <lb/>having lighted all the Weeks, we let in <lb/>the above-mention'd Wax into the Re­<lb/>ceiver, and made what ha&longs;te we could to <lb/>clo&longs;e it up with Cement. </s> <s>But though in <lb/>the mean while we left open the Valve <pb xlink:href="013/01/117.jpg" pagenum="77"/>of the Cylinder, the hole of the Stop­<lb/>cock and that in the Cover of the Re­<lb/>ceiver, that &longs;ome Air might get in to <lb/>cheri&longs;h the Flame and the &longs;moke might <lb/>have a vent; Yet for &longs;o great a Flame <lb/>the Air &longs;ufficed not &longs;o much as till the <lb/>Cover could be perfectly luted on: So <lb/>that before we were quite ready to imploy <lb/>the Pump, the Candle was extingui&longs;hed. <lb/></s> <s>Wherefore we took but one of the a­<lb/>bove mention'd Tapers, and having <lb/>lighted it, clo&longs;'d it up in the Receiver, to <lb/>try how long a &longs;mall Flame with a pro­<lb/>portionable &longs;moke would continue in <lb/>&longs;uch a quantity of Air: But we found <lb/>upon two &longs;everal tryals, that from the <lb/>beginning of pumping, the Flame went <lb/>out in about a minute of an hour. </s> <s>It <lb/>appear'd indeed to us that the &longs;winging <lb/>of the Wier to and fro (in the Engine <lb/>&longs;haken by pumping) ha&longs;ten'd the vani&longs;h­<lb/>ing of the Flame, which &longs;eem'd by that <lb/>motion to be ca&longs;t &longs;ometimes on one &longs;ide <lb/>of the Week and &longs;ometimes on the o­<lb/>ther; But though once we purpo&longs;ely <lb/>refrain'd pumping after a very few ex­<lb/>&longs;uctions of the Air, that the Flame might <lb/>not be agitated, yet it la&longs;ted not much <lb/>longer then the newly mention'd time. <pb xlink:href="013/01/118.jpg" pagenum="78"/>And la&longs;tly, clo&longs;ing up the &longs;ame Taper, <lb/>lighted again, to di&longs;cover how long it <lb/>would la&longs;t without drawing out of the <lb/>Air, we found that it burn'd for a while <lb/>vividly enough, but afterwards began to <lb/>be le&longs;&longs;en'd more and more in all its Di­<lb/>men&longs;ions. </s> <s>And we ob&longs;erv'd that the <lb/>Flame did not, as before, retire it &longs;elf by <lb/>little and little towards the top, but to­<lb/>wards the bottom of the Week (from <lb/>which yet it did a little withdraw upwards <lb/>ju&longs;t before it went out) &longs;o that the upper <lb/>part of the Week appear'd for a pretty <lb/>while manife&longs;tly above the top of the <lb/>Flame, which having la&longs;ted about five <lb/>minutes, was &longs;ucceeded by a directly a&longs;­<lb/>cending &longs;tream of Smoak. </s></p><p type="main"> <s>THere was taken a Wier, which being <lb/><arrow.to.target n="marg13"/><lb/>bent almo&longs;t in the form of a Screw, <lb/>con&longs;tituted &longs;uch an In&longs;trument to contein <lb/>Coals and leave them every way acce&longs;&longs;i­<lb/>ble to the Air, as the tenth Figure de­<lb/>clares; the breadth of this Ve&longs;&longs;el was no <lb/>le&longs;s then that it might with ea&longs;e be con­<lb/>vey'd into the Receiver: And having filld <lb/>it to the height of about five Inches with <lb/>throughly kindled Wood-coals, we let <pb xlink:href="013/01/119.jpg" pagenum="79"/>it down into the Gla&longs;s; and &longs;peedily clo­<lb/>&longs;ing it, we cau&longs;'d the Pumper to ply <lb/>his work, and ob&longs;erv'd that upon the ve­<lb/>ry fir&longs;t ex&longs;uction of the Air (though per­<lb/>haps not becau&longs;e of that onely) the Fire <lb/>in the Coals began to grow very dim, and <lb/>though the agitation of the Ve&longs;&longs;el did <lb/>make them &longs;wing up and down (which in <lb/>the free Air would have retarded the ex­<lb/>tinction of the Fire) yet when we could <lb/>no longer di&longs;cern any redne&longs;s at all in any <lb/>of them; ca&longs;ting our eyes upon a Minute­<lb/>Watch we kept by us on this occa&longs;ion, we <lb/>found that from the beginning of the <lb/>Pumping (which might be about two mi­<lb/>nutes after the Coals had been put in <lb/>glowing) to the total di&longs;-appearing of <lb/>the Fire, there had pa&longs;&longs;ed but three mi­<lb/>nutes. </s></p><p type="margin"> <s><margin.target id="marg13"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 11.</s></p><p type="main"> <s>Whereupon, to try the Experiment a <lb/>little further, we pre&longs;ently took out the <lb/>Coals, in which it &longs;eems there had re­<lb/>mained &longs;ome little parcels of Fire, rather <lb/>cover'd then totally quench'd: For in the <lb/>open Air the Coals began to be re-kind­<lb/>led in &longs;everal places, wherefore having by <lb/>&longs;winging them about in the Wier, <lb/>throughly lighted them the &longs;econd time, <lb/>welet them down again into the Receiver, <pb xlink:href="013/01/120.jpg" pagenum="80"/>and clo&longs;'d it &longs;peedily as before; and then <lb/>waiting till the Fire &longs;eem'd totally ex­<lb/>tinct without medling with the Pump, we <lb/>found that from the time the Ve&longs;&longs;el was <lb/>clo&longs;'d till that no Fire at all could be per­<lb/>ceiv'd there had pa&longs;&longs;ed about four mi­<lb/>nutes: Whereby it &longs;eem'd to appear that <lb/>the drawing away of the ambient Air <lb/>made the Fire go out &longs;ooner then other­<lb/>wi&longs;e it would have done; though that part <lb/>of the Air that we drew out left the more <lb/>room for the &longs;tifling &longs;teams of the Coals <lb/>to be received into. </s></p><p type="main"> <s>La&longs;tly, Having taken out the Wier <lb/>and put other Coals into it, we did, in the <lb/>&longs;ame Room where the Engine &longs;tood, let it <lb/>hang quietly by a &longs;tring in the open Air, <lb/>to try how long the Fire would la&longs;t with­<lb/>out agitation when no Air was kept from <lb/>it. </s> <s>And we found that the Fire began to <lb/>go out fir&longs;t at the top and out-&longs;ides of the <lb/>Coals; but inwards and near the bottom <lb/>the Fire continu'd vi&longs;ible for above half <lb/>an hour, a great part of the Coals, e&longs;pe­<lb/>cially tho&longs;e next the bottom, being burnt <lb/>to a&longs;hes before the Fire went out. </s></p><p type="main"> <s>We cau&longs;'d likewi&longs;e a piece of Iron to <lb/>be forg'd, of the bigne&longs;s of a middle &longs;iz'd <lb/>Char-coal, and having made it red hot <pb xlink:href="013/01/121.jpg" pagenum="81"/>throughout; we cau&longs;'d it in the lately <lb/>mention'd Wier, to be &longs;peedily convey'd <lb/>and &longs;hut up into the Receiver, being de­<lb/>&longs;irous to try what would become of a <lb/>glowing Body, by rea&longs;on of its texture <lb/>more vehemently hot then a burning <lb/>Coal of the &longs;ame bigne&longs;s, & yet unlike to <lb/>&longs;end forth &longs;uch copious & &longs;tifling Fumes: <lb/>But we could not ob&longs;erve any manife&longs;t <lb/>change upon the ex&longs;uction of the Air. <lb/></s> <s>The Iron began indeed to lo&longs;e its Fiery <lb/>redne&longs;s at the top, but that &longs;eem'd to be <lb/>becau&longs;e it was it the upper end &longs;omewhat <lb/>more &longs;lender then at the lower: The red­<lb/>ne&longs;s, though it were in the day time, con­<lb/>tinued vi&longs;ible about four minutes; and <lb/>then, before it did quite di&longs;-appear, we <lb/>turn'd the Key of the Stop-cock but <lb/>could not di&longs;cern any change of the Iron <lb/>upon the ru&longs;hing in of the Air. </s> <s>Yet &longs;ome <lb/>little remainders of Wax that &longs;tuck to <lb/>the Wier, and were turn'd into Fumes by <lb/>the heat of the neighboring Iron, &longs;eem'd <lb/>to afford a more plentiful, or at lea&longs;t a <lb/>much more free expanded &longs;moke when <lb/>the Air was &longs;uck'd out, then afterwards; <lb/>though allowance was made for the de­<lb/>crea&longs;ing heat of the Iron. </s> <s>And la&longs;tly, <lb/>notwith&longs;tanding a con&longs;iderable ex&longs;uction <pb xlink:href="013/01/122.jpg" pagenum="82"/>of the ambient Air, though not by far &longs;o <lb/>great a one as might have been made by <lb/>the Engine; and notwith&longs;tanding the in­<lb/>con&longs;iderable di&longs;&longs;ipation of the parts of the <lb/>Iron, the &longs;urrounding &longs;ides of the Recei­<lb/>ver were &longs;en&longs;ibly, and almo&longs;t offen&longs;ively <lb/>heated by it; in&longs;omuch that a pretty while <lb/>after the Iron was taken out, the &longs;ides of <lb/>the Gla&longs;s manife&longs;tly retain'd a warmth: <lb/>which would not be unfit to be con&longs;ider'd <lb/>by a Per&longs;on at more lea&longs;ure then I am <lb/>now. </s></p><p type="main"> <s>BEing willing to try after this &longs;ome­<lb/><arrow.to.target n="marg14"/><lb/>thing that would not cheri&longs;h much <lb/>Fire at once, and would keep Fire much <lb/>longer then a Coal. </s> <s>We took a piece of <lb/>Match, &longs;uch as Souldiers u&longs;e, of the thick­<lb/>ne&longs;s of a Mans little Finger, or &longs;omewhat <lb/>thicker; and this being well lighted at <lb/>one end, was by a &longs;tring &longs;u&longs;pended with <lb/>that end downwards in the cavity of the <lb/>Receiver which was immediately clo&longs;'d: <lb/>And yet by that time it could well be &longs;o, <lb/>the copious Fumes of the Match had neer <lb/>fill'd and darken'd the Receiver. </s> <s>Where­<lb/>fore, le&longs;t the Ve&longs;&longs;el &longs;hould be endanger'd, <lb/>the Pump was nimbly ply'd, and a great <pb xlink:href="013/01/123.jpg" pagenum="83"/>deal of Air and Smoke mixt together was <lb/>drawn out, whereby the Receiver grow­<lb/>ing more clear, we could di&longs;cern the Fire <lb/>in the Match to burn more and more lan­<lb/>guidly: And notwith&longs;tanding that by the <lb/>diligence u&longs;'d in Pumping, it &longs;eem'd to <lb/>have room enough allow'd it to throw <lb/>out Fumes; yet after no long time it <lb/>cea&longs;'d from being di&longs;cernable either by its <lb/>Light or its Smoke. </s> <s>And though by <lb/>that we were invited to &longs;uppo&longs;e it quite <lb/>extingui&longs;hed, yet we continu'd pumping <lb/>a while, in pro&longs;ecution of another Expe­<lb/>riment we were trying at the &longs;ame time: <lb/>And this we did the more willingly be­<lb/>cau&longs;e of a &longs;u&longs;picion the Experiment a­<lb/>bout the Coals might ea&longs;ily &longs;ugge&longs;t, and <lb/>which the event declar'd not to have been <lb/>altogether groundle&longs;s. </s> <s>For upon the <lb/>Admi&longs;&longs;ion of the external Air, the Fire, <lb/>that &longs;eem'd to have gone out a pretty <lb/>while before, did pre&longs;ently revive; and <lb/>being as it were refre&longs;h d by the new Air, <lb/>and blown by the Wind made by that <lb/>Air in ru&longs;hing in, it began again to &longs;hine <lb/>and di&longs;&longs;ipate the neighboring Fuel into <lb/>Smoke as formerly. </s></p><pb xlink:href="013/01/124.jpg" pagenum="84"/><p type="margin"> <s><margin.target id="marg14"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 12.</s></p><p type="main"> <s>A While after we let down into <lb/><arrow.to.target n="marg15"/><lb/>the Receiver together with a ligh­<lb/>ted piece of Match, a great Bladder well <lb/>tyed at the Neck, but very lank, as not <lb/>containing actually much (if any thing) a­<lb/>bove a Pint of Air, but being capable of <lb/>containing ten or twelve times as much. </s></p><p type="margin"> <s><margin.target id="marg15"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 13.</s></p><p type="main"> <s>Our &longs;cope in this Experiment was <lb/>partly to try whether or no the &longs;moke of <lb/>the Match, repleni&longs;hing the Receiver, <lb/>would be able to hinder the Dilatation of <lb/>the inward Air, upon the ex&longs;uction of the <lb/>Ambient. </s> <s>And partly to di&longs;cover whe­<lb/>ther the extinction of the Fire in the <lb/>Match did proceed from want of Air, or <lb/>barely from the pre&longs;&longs;ure of its own <lb/>Fumes, which for want of room to ex­<lb/>pand them&longs;elves in, might be &longs;uppo&longs;'d <lb/>to Recoyl upon the Fire, and &longs;o to <lb/>&longs;tifle it. </s></p><p type="main"> <s>The event of our tryal was, That <lb/>at the beginning of our Pumping the <lb/>Match appear'd well lighted, though <lb/>it had almo&longs;t fill'd the Receiver with <lb/>its plentiful Fumes: But by degrees it <lb/>burnt more and more dimly, notwith­<lb/>&longs;tanding that by the nimble drawing <pb xlink:href="013/01/125.jpg" pagenum="85"/>out the Air and Smoke, the Ve&longs;&longs;el <lb/>were made le&longs;s opacous, and le&longs;s full of <lb/>compre&longs;&longs;ing matter; as appeard by this, <lb/>That the longer we pump'd, the le&longs;&longs;er <lb/>Air and Smoke came out of the Cylin­<lb/>der at the opening the Valve, and con&longs;e­<lb/>quently the le&longs;s came into it before; yet <lb/>the Fire in the Match went but &longs;lowly <lb/>out. </s> <s>And when afterwards, to &longs;atisfie <lb/>our &longs;elves of its expiration, we had dar­<lb/>ken'd the Room, and in vain endeavored <lb/>to di&longs;cover any &longs;park of Fire, as we could <lb/>not for &longs;ome time before by the help of <lb/>Candles di&longs;cern the lea&longs;t ri&longs;ing of Smoke, <lb/>we yet continued pumping &longs;ix or &longs;even <lb/>times; and after all that letting in the <lb/>Air, the &longs;eemingly dead Fire quickly <lb/>revived, and manife&longs;ted its recovery by <lb/>Light and &longs;tore of Smoke, with the <lb/>latter of which it quickly began to re­<lb/>pleni&longs;h the Receiver. </s> <s>Then we fell <lb/>to pumping afre&longs;h, and continued that <lb/>labour &longs;o long till the re-kindled <lb/>Match went out again: and thinking <lb/>it then fit not to cea&longs;e from Pum­<lb/>ping &longs;o &longs;oon as before, we found that <lb/>in le&longs;s then half a quarter of an hour the <lb/>Fire was got out for good and all, <pb xlink:href="013/01/126.jpg" pagenum="86"/>and pa&longs;t the po&longs;&longs;ibility of being recover'd <lb/>by the re-admitted Air. </s></p><p type="main"> <s>Some Circum&longs;tances, be&longs;ides tho&longs;e al­<lb/>ready mention'd, occurr'd in the making <lb/>of the Experiment, of which the&longs;e are <lb/>the principal. </s></p><p type="main"> <s>Fir&longs;t, when the Receiver was full of <lb/>Smoke, if the Cylinder were emptied, <lb/>immediately upon the turning of the <lb/>Stop-cock, the Receiver would appear <lb/>manife&longs;tly darken'd to his eye that look'd <lb/>upon the light through it: and this dark­<lb/>ne&longs;s was much le&longs;s when the Receiver was <lb/>much le&longs;s fill'd with Fumes: It was al&longs;o <lb/>in&longs;tantaneous, and &longs;eem'd to proceed from <lb/>a &longs;udden change of place and &longs;cituation <lb/>in the exhalations, upon the vent &longs;ud­<lb/>denly afforded them and the Air they <lb/>were mixt with, out of the Receiver into <lb/>the Cylinder. </s></p><p type="main"> <s>The next thing we ob&longs;erv'd was, a kinde <lb/>of <emph type="italics"/>Halo<emph.end type="italics"/> that appear'd a good while about <lb/>the Fire, and &longs;eem'd to be produced by <lb/>the &longs;urrounding Exhalations. </s></p><p type="main"> <s>And la&longs;tly, it is remarkable, That even <lb/>when the Fumes &longs;eemed mo&longs;t to reple­<lb/>ni&longs;h the Receiver, they did not &longs;en&longs;ibly <lb/>hinder the Air included in the Bladder <lb/>from dilating it &longs;elf after the &longs;ame manner <pb xlink:href="013/01/127.jpg" pagenum="87"/>(for ought we could di&longs;cern) as it would <lb/>have otherwi&longs;e done: So that before the <lb/>Fire or the Match was quite extinct, the <lb/>Bladder appear'd &longs;well'd at lea&longs;t to &longs;ix or <lb/>&longs;even times its former capacity. </s></p><p type="main"> <s>Since the writing of the&longs;e la&longs;t Lines, <lb/>we took a &longs;mall Receiver, capable of <lb/>containing (by gue&longs;s) about a pound and <lb/>a half of Water; and in the mid&longs;t of it <lb/>we &longs;u&longs;pended a lighted Match, but though <lb/>within one minute of an hour (or there­<lb/>abouts) from the putting in of the Match, <lb/>we had cemented on the Cover, yet we <lb/>could not make &longs;uch ha&longs;te, but that before <lb/>we began to pump, the Smoke had &longs;o <lb/>fill'd that &longs;mall Receiver, as for ought we <lb/>di&longs;cern'd, to choke the Fire. </s> <s>And having <lb/>again and again reiterated the Experi­<lb/>ment, it &longs;eem'd &longs;till as at fir&longs;t, that we <lb/>could not clo&longs;e up the Ve&longs;&longs;el and pump <lb/>out all the Fumes time enough to re&longs;cue <lb/>the Fire from Extinction; whereupon we <lb/>made u&longs;e of this Expedient. </s> <s>A&longs;&longs;oon as <lb/>we had pump'd once or twice, we &longs;udden­<lb/>ly turn'd the Key, and thereby gave acce&longs;s <lb/>to the excluded Air, which ru&longs;hing vio­<lb/>lently in, as if it had been forced thorow <lb/>a pair of Bellows, did both drive away <lb/>the a&longs;hes, fill the Gla&longs;s with fre&longs;h Air, and <pb xlink:href="013/01/128.jpg" pagenum="88"/>by blowing the almo&longs;t extingui&longs;h'd Fire, <lb/>re-kindl'd it, as appear'd by the Matches <lb/>beginning again to &longs;moke, which before it <lb/>had cea&longs;'d to do; we having by this <lb/>means obtain'd a lighted Match in the <lb/>Receiver, without being reduc'd to &longs;pend <lb/>time to clo&longs;e it up, commanded the Air <lb/>to be immediatly pump'd out, and found <lb/>that upon the ex&longs;uction of it, the Match <lb/>quickly left &longs;mokeing, as it &longs;eem'd, by <lb/>rea&longs;on of the ab&longs;ence of the Air; and <lb/>yet if &longs;ome urgent occa&longs;ions had not hin­<lb/>der'd us, we would for greater &longs;ecurity <lb/>have try'd, whether or no the Match re­<lb/>kindled as formerly, would &longs;moke much <lb/>longer, in ca&longs;e of no ex&longs;uction of the am­<lb/>bient Air. </s></p><p type="main"> <s>TO try diver&longs;e things at once, <lb/><arrow.to.target n="marg16"/><lb/>and particularly whether Fire, <lb/>though we found it would not long la&longs;t, <lb/>might not yet be produced in our eva­<lb/>cuated Receiver: We took a Pi&longs;tol of <lb/>about a Foot in length, and having <lb/>firmly tyed it to a &longs;tick almo&longs;t as long as <lb/>the Cavity of the Receiver, we very <lb/>carefully prim'd it with well dry'd Gun­<lb/>powder, and then cocking it, we ty'd to <pb xlink:href="013/01/129.jpg" pagenum="89"/>the Tricker one end of a &longs;tring, who&longs;e <lb/>other end was fa&longs;ten'd to the Key former­<lb/>ly mention'd to belong to the Cover of <lb/>our Receiver. </s> <s>This done, we convey'd <lb/>the Pi&longs;tol, together with the annexed <lb/>Staff, into the Ve&longs;&longs;el: which being clo&longs;'d <lb/>up, and empty'd after the u&longs;ual man­<lb/>ner, we began to turn the Key in the <lb/>Cover; and thereby &longs;hortning the &longs;tring <lb/>that reach'd from it to the Pi&longs;tol, we <lb/>pull'd a&longs;ide the Tricker, and ob&longs;erv'd, <lb/>that according to our expectation the <lb/>force of the Spring of the Lock was <lb/>not &longs;en&longs;ibly abated by the ab&longs;ence of <lb/>the Air. (from who&longs;e <emph type="italics"/>impetus<emph.end type="italics"/> yet &longs;ome <lb/>Modern Naturali&longs;ts would derive the <lb/>cau&longs;e of the motion of Re&longs;titution in <lb/>&longs;olid Bodies) For the Cock falling <lb/>with its wonted violence upon the Steel, <lb/>&longs;truck out of it as many and as con&longs;pi­<lb/>cuous parts of Fire, as, for ought we <lb/>could perceive, it would have done in <lb/>the open Air. </s> <s>Repeating this Experi­<lb/>ment divers times, we al&longs;o ob&longs;erved <lb/>whether or no there would appear <lb/>any con&longs;iderable Diver&longs;ity in the <lb/>Motion of the &longs;hining Sparks in a <lb/>place where the remaining Aire was <lb/>&longs;o much rarified, but could not perceive <pb xlink:href="013/01/130.jpg" pagenum="100"/>but that they moved &longs;ome of them up­<lb/>wards, as well as &longs;ome of them down­<lb/>wards, and &longs;ome of them &longs;ide-ways, as <lb/>they are wont to do, when upon &longs;uch col­<lb/>li&longs;ions they fly out in the open Air. </s></p><p type="margin"> <s><margin.target id="marg16"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 14.</s></p><p type="main"> <s>We likewi&longs;e cau&longs;'d a piece of Steel to <lb/>be made of the form and bigne&longs;s of the <lb/>Flint, in who&longs;e place we put it, and then <lb/>the Pi&longs;tol being cock'd and conveyed in­<lb/>to the Receiver, the Trigger was pull'd <lb/>after the Air was drawn out: And though <lb/>the place were purpo&longs;ely &longs;omewhat dar­<lb/>ken'd, yet there appear'd not upon the <lb/>&longs;triking of the two Steels again&longs;t each o­<lb/>ther the lea&longs;t &longs;park of Fire: Nor did we <lb/>expect any (having before in vain attem­<lb/>pted to &longs;trike Fire this way in the open <lb/>Air) though we thought fit to make the <lb/>Experiment to undeceive tho&longs;e who fan­<lb/>cy in rarified Air, I know not what &longs;trange <lb/>di&longs;po&longs;ition, to take Fire upon a much <lb/>&longs;lighter occa&longs;ion then this Experiment <lb/>afforded. </s> <s>We have indeed found, that <lb/>by the dextrous Colli&longs;ion of two har­<lb/>den'd pieces of Steel, &longs;tore of &longs;parks <lb/>may be &longs;truck out: But that was done with <lb/>&longs;uch vehement percu&longs;&longs;ion of the edges of <lb/>the two Steels, as could not well be com­<lb/>pa&longs;&longs;'d in our Receiver. </s></p><pb xlink:href="013/01/131.jpg" pagenum="101"/><p type="main"> <s>But the chief thing we de&longs;ign'd to do <lb/>with our Pi&longs;tol, was, To ob&longs;erve whe­<lb/>ther Gun-powder would take Fire in our <lb/>empty'd and clo&longs;ely &longs;top'd Gla&longs;s? </s> <s>Whe­<lb/>ther the expan&longs;ion of the Flame would be <lb/>con&longs;iderably varied by the ab&longs;ence of &longs;o <lb/>much of the ambient Air as was drawn <lb/>out of the Receiver? </s> <s>and whether the <lb/>Flame would diffu&longs;e it &longs;elf upward, as it is <lb/>wont, notwith&longs;tanding its not having a­<lb/>bout it the u&longs;ual proportion of Air to <lb/>force it up? </s> <s>And though mo&longs;t of our at­<lb/>tempts to fire the Gun-powder in the <lb/>Pan of the Pi&longs;tol &longs;ucceeded not, becau&longs;e <lb/>we were fain to let it hang almo&longs;t perpen­<lb/>dicular in the Receiver; whereby the <lb/>Powder was &longs;haken down before the <lb/>&longs;parks could reach it: yet once the Ex­<lb/>periment &longs;ucceeded, and the kindled <lb/>Powder &longs;eem'd to make a more expanded <lb/>Flame then it would have done in the <lb/>open Air, but mounted upwards accord­<lb/>ing to its wont, whether by rea&longs;on of that <lb/>little portion of Air, which in &longs;pight of <lb/>our pumping remained in the Receiver, or <lb/>for any other cau&longs;e, we have not now the <lb/>lei&longs;ure to con&longs;ider. </s> <s>But we mu&longs;t not for­<lb/>get, that upon the extinction of the Flame <lb/>the Receiver appear'd darken'd with <pb xlink:href="013/01/132.jpg" pagenum="102"/>&longs;moke, which &longs;eem'd to move freely up <lb/>and down, and upon the letting in the Air <lb/>at the Stop-cock began to circulate much <lb/>fa&longs;ter then before. </s> <s>We wonld have made <lb/>more ob&longs;ervations concerning this Flame, <lb/>but that of two or three attempts we <lb/>afterwards made to repeat the kindling of <lb/>Powder, not any one &longs;ucceeded; and <lb/>we have not the lea&longs;ure to dwell long up­<lb/>on one kinde of Tryals. </s></p><p type="main"> <s>TO the&longs;e Experiments concerning Fire <lb/><arrow.to.target n="marg17"/><lb/>we added another, which, though it &longs;uc­<lb/>ceded not, may perhaps without imper­<lb/>tinency be recorded: partly becau&longs;e that <lb/>(as we have in another Treati&longs;e amply de­<lb/>clar'd) it is u&longs;efull to recite what Experi­<lb/>ments mi&longs;carry as well as what &longs;ucceed. <lb/></s> <s>And partly al&longs;o becau&longs;e it is very po&longs;&longs;ible <lb/>that what we endeavored in vaine, may be <lb/>performed by Your Lord&longs;hip, or &longs;ome <lb/>other <emph type="italics"/>Virtuo&longs;o<emph.end type="italics"/> that &longs;hall have &longs;lancker <lb/>Ve&longs;&longs;ells then we had, and more Sunny <lb/>dayes then the pre&longs;ent Winter allows <lb/>us. </s></p><p type="margin"> <s><margin.target id="marg17"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 15.</s></p><p type="main"> <s>We convey'd then into one of our &longs;mall <lb/>Receivers a piece of matter combu&longs;tible, <lb/>dry and black (experience declaring things <pb xlink:href="013/01/133.jpg" pagenum="103"/>of that colour to be mo&longs;t ea&longs;ily kindled) <lb/>& carefully clo&longs;ing the Ve&longs;&longs;el we brought <lb/>it to a Window at which the Sun, not very <lb/>faire from the Meridian, &longs;hone in very free­<lb/>ly: then drawing out the Aire with &longs;peed <lb/>united the Sun-beames with a burning <lb/>Gla&longs;s upon the combu&longs;tible matter which <lb/>began immediatly to &longs;end forth a Smoke <lb/>that quickly darkned the Receiver, but <lb/>notwith&longs;tanding all our care and diligence <lb/>the externall Aire got in &longs;o fa&longs;t that after <lb/>diver&longs;e tryals we were fayne to leave off <lb/>the Experiment in that Gla&longs;&longs;e and induc'd <lb/>to make tryall of it in our great Re­<lb/>ceiver. </s></p><p type="main"> <s>Haveing then after &longs;ome difficulty <lb/>lodg'd the combu&longs;tible matter in the ca­<lb/>vity of this Ve&longs;&longs;ell in &longs;uch manner as that <lb/>it was almo&longs;t contiguous to that &longs;ide <lb/>thereof that was next the Sun, we did en­<lb/>deavor with a pretty large burning Gla&longs;s <lb/>to kindle it, but found, as we fear'd, <lb/>That by rea&longs;on of the thickne&longs;s of the <lb/>Gla&longs;s, (which was al&longs;o of a le&longs;s pure and <lb/>le&longs;s Diaphanous matter then the o­<lb/>ther) the Sun-beams thrown in by the <lb/>burning Gla&longs;s, were in their pa&longs;&longs;age <lb/>&longs;o Di&longs;located and Scattered (not now to <lb/>mention tho&longs;e many that being reflected, <pb xlink:href="013/01/134.jpg" pagenum="104"/>I could not pierce into the cavity of the <lb/>Receiver) that we could not po&longs;&longs;ibly u­<lb/>nite enough of them to kindle the matter, <lb/>nor &longs;o much as to make it &longs;en&longs;ibly &longs;moke. <lb/></s> <s>Yet we hope that the &longs;eeing whether Bo­<lb/>dies (other then Gun-powder) may be <lb/>kindled, and what would happen to them <lb/>when &longs;et on fire, in a place in great mea­<lb/>&longs;ure devoid of Air, may prove &longs;o Lucife­<lb/>rous an Experiment, that when the Sea­<lb/>&longs;on is more favorable we &longs;hall, God per­<lb/>mitting, make further tryal of it, and ac­<lb/>quaint Your Lord&longs;hip with the Event, if <lb/>it prove pro&longs;perous. </s> <s>In the mean time <lb/>we &longs;hall pa&longs;s on to other Experiments, <lb/>a&longs;&longs;oon as we have adverti&longs;'d Your Lord­<lb/>&longs;hip that we have forborn to make &longs;uch <lb/>Reflections upon the &longs;everal Experiments <lb/>we have &longs;et down concerning Fire, as the <lb/>matter would have ea&longs;ily enough afford­<lb/>ed, and Your Lord&longs;hip may perhaps have <lb/>expected. </s> <s>But I made the le&longs;s &longs;cruple to <lb/>forbear the annexing of Speculations to <lb/>the&longs;e Recitals, becau&longs;e <emph type="italics"/>Carneades<emph.end type="italics"/> & <emph type="italics"/>Eleu­<lb/>therius<emph.end type="italics"/> have in &longs;ome Dialogues concern­<lb/>ing Heat and Flame, which were la&longs;t year <lb/>&longs;een by &longs;ome Friends, and may be, when <lb/>you plea&longs;e, commanded by You, men-<pb xlink:href="013/01/135.jpg" pagenum="105"/>tion'd divers of my Thoughts and Expe­<lb/>riments concerning Fire. </s></p><p type="main"> <s>WE de&longs;igned to try whether or no <lb/><arrow.to.target n="marg18"/><lb/>divers Magnetical Experiments <lb/>would exhibit any unu&longs;ual <emph type="italics"/>Phænomena,<emph.end type="italics"/><lb/>being made in our Evacuated Receiver <lb/>in&longs;tead of the open Air: But for want of <lb/>lei&longs;ure and conveniency to pro&longs;ecute &longs;uch <lb/>Tryals, we were induced to re&longs;erve the <lb/>re&longs;t for an other time, and to content our <lb/>&longs;elves with making that which follows. <lb/></s> <s>We convey'd into the Receiver a little <lb/>Pede&longs;tal of Wood, in the mid&longs;t of which <lb/>was perpendicularly erected a &longs;lender <lb/>Iron, upon who&longs;e &longs;harp point an excited <lb/>Needle of Steel purpo&longs;ely made, and of <lb/>about five Inches long, was &longs;o placed <lb/>that hanging in an <emph type="italics"/>Æquilibrium<emph.end type="italics"/> it could <lb/>move freely towards either hand. </s> <s>Then <lb/>the Air being after the u&longs;ual manner <lb/>pumped out, we apply'd a Load-&longs;tone <lb/>moderately vigorous to the out-&longs;ide of <lb/>of the Gla&longs;s, and found that it Attracted <lb/>or Repell'd the ends of the Needle, accor­<lb/>ding to the Laws Magnetical, without <lb/>any remarkable difference from what the <lb/>&longs;ame Load-&longs;tone would have done had <pb xlink:href="013/01/136.jpg" pagenum="106"/>none of the Air been drawn away from a­<lb/>bout the Needle, which when the Load­<lb/>&longs;tone was removed, after &longs;ome tremu­<lb/>lous Vibrations to and fro, re&longs;ted in a po­<lb/>&longs;ition wherein it look'd North and <lb/>South. </s></p><p type="margin"> <s><margin.target id="marg18"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 16</s></p><p type="main"> <s>PRoceed we now to the mention of <lb/><arrow.to.target n="marg19"/><lb/>that Experiment, whereof the &longs;ati&longs;­<lb/>factory tryal was the principal Fruit I <lb/>promi&longs;'d my &longs;elf from our Engine. </s> <s>It <lb/>being then &longs;ufficiently known, that, in <lb/>the Experiment <emph type="italics"/>De Vacuo,<emph.end type="italics"/> the Quick­<lb/>&longs;ilver in the Tube is wont to remain ele­<lb/>vated, above the &longs;urface of that whereon <lb/>it leans, about 27 digits: I con&longs;idered, <lb/>that, if the true and onely rea&longs;on why the <lb/>Quick-&longs;ilver falls no lower, be, that at <lb/>that Altitude, the Mercurial Cylinder in <lb/>the Tube, is an <emph type="italics"/>Æquilibrium<emph.end type="italics"/> with the <lb/>Cylinder of Air, &longs;uppo&longs;'d to reach from <lb/>the adjacent Mercury to the top of the <lb/>Atmo&longs;phere: If this Experiment could <lb/>be try'd out of the Atmo&longs;phere, the <lb/>Quick-&longs;ilver in the Tube would fall <lb/>down to a levell with that in the Ve&longs;&longs;el, <lb/>&longs;ince then there would be no pre&longs;&longs;ure up­<lb/>on the Subjacent, to re&longs;i&longs;t the weight of <pb xlink:href="013/01/137.jpg" pagenum="107"/>the Incumbent Mercury. </s> <s>Whence I in­<lb/>ferr'd (as ea&longs;ily I might) that, if the Ex­<lb/>periment could be try'd in our Engine, the <lb/>Quick-&longs;ilver would &longs;ub&longs;ide below 27 Di­<lb/>gits, in proportion to the ex&longs;uction of <lb/>Air, that &longs;hould be made out of the Re­<lb/>ceiver. </s> <s>For, as when the Air is &longs;hut in­<lb/>to the Receiver, it does (according to <lb/>what hath above been taught) continue <lb/>there as &longs;trongly compre&longs;&longs;'d, as it did <lb/>whil'&longs;t all the incumbent Cylinder of the <lb/>Atmo&longs;phere lean'd immediatly upon it; <lb/>becau&longs;e the Gla&longs;s, wherein it is pent up, <lb/>hinders it to deliver it &longs;elf, by an expan&longs;i­<lb/>on of its parts, from the pre&longs;&longs;ure where­<lb/>with it was &longs;hut up. </s> <s>So, if we could per­<lb/>fectly draw the Air out of the Receiver, <lb/>it would conduce as well to our purpo&longs;e, <lb/>as if we were allow'd to try the Experi­<lb/>ment beyond the Atmo&longs;phere. </s></p><p type="margin"> <s><margin.target id="marg19"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 17.</s></p><p type="main"> <s>Wherefore (after having &longs;urmounted <lb/>&longs;ome little difficulties which occurr'd at <lb/>the beginning) the Experiment was made <lb/>after this manner. </s> <s>We took a &longs;lender and <lb/>very curiou&longs;ly blown Cylinder of Gla&longs;s, <lb/>of near three Foot in length, and who&longs;e <lb/>bore had in Diameter a quarter of an Inch, <lb/>wanting a hairs breadth: This Pipe being <lb/>Hermetically &longs;eal'd at one end, was, at <pb xlink:href="013/01/138.jpg" pagenum="108"/>the other, fill'd with Quick-&longs;ilver, care <lb/>being taken in the filling, that as few <lb/>bubles as was po&longs;&longs;ible &longs;hould be left in the <lb/>Mercury: Then the Tube being &longs;topt <lb/>with the Finger and inverted, was open'd, <lb/>according to the manner of the Experi­<lb/>ment, into a &longs;omewhat long and &longs;lender <lb/>Cylindrical Box (in&longs;tead of which we now <lb/>are wont to u&longs;e a Gla&longs;s of the &longs;ame form) <lb/>half fill'd with Quick-&longs;ilver: And &longs;o, the <lb/>liquid metal being &longs;uffered to &longs;ub&longs;ide, and <lb/>a piece of Paper being pa&longs;ted on levell <lb/>with its upper &longs;urface, the Box and Tube <lb/>and all were by &longs;trings carefully let down <lb/>into the Receiver, and then, by means of <lb/>the hole formerly mention'd to be left in <lb/>the Cover, the &longs;aid Cover was &longs;lip't along <lb/>as much of the Tube as reach'd above the <lb/>top of the Receiver; And the Interval, <lb/>left betwixt the &longs;ides of the Hole and <lb/>tho&longs;e of the Tube, was very exqui&longs;itely <lb/>fill'd up with melted (but not over hot) <lb/>Diachylon; and the round chink, betwixt <lb/>the Cover and the Receiver, was likewi&longs;e <lb/>very carefully clo&longs;'d up: Upon which clo­<lb/>&longs;ure there appear'd not any change in the <lb/>height of the Mercurial Cylinder; no <lb/>more, then if the interpo&longs;'d Gla&longs;s Recei­<lb/>ver did not hinder the immediate pre&longs;&longs;ure <pb xlink:href="013/01/139.jpg" pagenum="109"/>of the ambient Atmo&longs;phere upon the <lb/>inclo&longs;ed Air; which hereby appears to <lb/>bear up on the Mercury, rather by virtue <lb/>of its &longs;pring, then of its weight: &longs;ince its <lb/>weight cannot be &longs;uppo&longs;'d to amount to <lb/>above two or three Ounces, which is in­<lb/>con&longs;iderable in compari&longs;on of &longs;uch a Cy­<lb/>linder of Mercury as it would keep from <lb/>&longs;ub&longs;iding. </s></p><p type="main"> <s>All things being thus in a readine&longs;s, the <lb/>Sucker was drawn down; and, immedi­<lb/>ately upon the egre&longs;s of a Cylinder of <lb/>Air out of the Receiver; the Quick-&longs;ilver <lb/>in the Tube did, according to expectati­<lb/>on, &longs;ub&longs;ide: and notice being carefully <lb/>taken (by a mark fa&longs;ten'd to the out&longs;ide) <lb/>of the place where it &longs;topt, we cau&longs;'d him <lb/>that manag'd the Pump to pump again, <lb/>and mark'd how low the Quick-&longs;ilver fell <lb/>at the &longs;econd ex&longs;uction; but continuing <lb/>this work, we were quickly hindred from <lb/>accurately marking the Stages made by <lb/>the Mercury in its de&longs;cent, becau&longs;e it &longs;oon <lb/>&longs;unk below the top of the Receiver; &longs;o <lb/>that we could thenceforward mark it no <lb/>other ways then by the eye. </s> <s>And thus, <lb/>continuing the labor of pumping for a­<lb/>bout a quarter of an hour, we found our <lb/>&longs;elves unable to bring the Quick-&longs;ilver in <pb xlink:href="013/01/140.jpg" pagenum="110"/>the Tube totally to &longs;ub&longs;ide; becau&longs;e, <lb/>when the Receiver was con&longs;iderably em­<lb/>pty'd of its Air, and con&longs;equently that <lb/>little that remain'd grown unable to re&longs;i&longs;t <lb/>the Irruption of the external, that Air <lb/>would (in &longs;pight of whatever we could <lb/>do) pre&longs;s in at &longs;ome little Avenue or <lb/>other; and though much could not there­<lb/>at get in, yet a little was &longs;ufficient to coun­<lb/>terballance the pre&longs;&longs;ure of &longs;o &longs;mall a Cy­<lb/>linder of Quick-&longs;ilver, as then remain'd <lb/>in the Tube. </s></p><p type="main"> <s>Now (to &longs;atisfie our &longs;elves further, that <lb/>the failing of the Quick-&longs;ilver in the <lb/>Tube to a determinate height, proceeds <lb/>from the <emph type="italics"/>Æquilibrium,<emph.end type="italics"/> wherein it is at <lb/>that height with the external Air, the one <lb/>gravitating, the other pre&longs;&longs;ing with equal <lb/>force upon the &longs;ubjacent Mercury) we Re­<lb/>turned the Key and let in &longs;ome new Air; <lb/>upon which the Mercury immediatly be­<lb/>gan to a&longs;cend (or rather to be impell'd up­<lb/>wards) in the Tube, and continu'd a&longs;cend­<lb/>ing, till having Return'd the Key it im­<lb/>mediatly re&longs;ted at the height which it had <lb/>then attain'd: And &longs;o, by Turning and <lb/>Returning the Key, we did &longs;everal times <lb/>at plea&longs;ure impel it upwards, and check its <lb/>a&longs;cent. </s> <s>And la&longs;tly, having given a free <pb xlink:href="013/01/141.jpg" pagenum="111"/>egre&longs;s at the Stop-cock to as much of the <lb/>external Air as would come in, the Quick­<lb/>&longs;ilver was impell'd up almo&longs;t to its fir&longs;t <lb/>height: I &longs;ay almo&longs;t, becau&longs;e it &longs;topt <lb/>near a quarter of an Inch beneath the Pa­<lb/>per mark formerly mention'd; which we <lb/>a&longs;crib'd to this, That there was (as is u­<lb/>&longs;ual in this Experiment) &longs;ome little Parti­<lb/>cles of Air engag'd among tho&longs;e of the <lb/>Quick-&longs;ilver; which Particles, upon the <lb/>de&longs;cent of the Quick-&longs;ilver, did manife&longs;t­<lb/>ly ri&longs;e up in Bubbles towards the top of <lb/>the Tube, and by their pre&longs;&longs;ure, as well <lb/>as by le&longs;&longs;ening the Cylinder by as much <lb/>room as they formerly took up in it, hin­<lb/>der'd the Quick-&longs;ilver from regaining its <lb/>fir&longs;t height. </s></p><p type="main"> <s>This Experiment was a few days after <lb/>repeated in the pre&longs;ence of tho&longs;e excellent <lb/>and de&longs;ervedly Famous Mathematick <lb/>Profe&longs;&longs;ors, Dr. <emph type="italics"/>Wallis,<emph.end type="italics"/> Dr. <emph type="italics"/>Ward,<emph.end type="italics"/> and Mr. <lb/><emph type="italics"/>Wren,<emph.end type="italics"/> who were plea&longs;ed to Honor it with <lb/>their Pre&longs;ence: And whom I name, both <lb/>as ju&longs;tly counting it an Honor to be <lb/>known to them, and as being glad of &longs;uch <lb/>Judicious and illu&longs;trious Witne&longs;&longs;es of our <lb/>Experiment; and 'twas by their gue&longs;s that <lb/>the top of the Quick-&longs;ilver in the Tube <lb/>was defin'd to be brought within an Inch <pb xlink:href="013/01/142.jpg" pagenum="112"/>of the &longs;urface of that in the Ve&longs;&longs;el. </s></p><p type="main"> <s>And here, for the Illu&longs;tration of the <lb/>foregoing Experiment, it will not be a­<lb/>mi&longs;s to mention &longs;ome other particulars <lb/>relating to it. </s></p><p type="main"> <s>Fir&longs;t then, When we endeavor'd to <lb/>make the Experiment with the Tube <lb/>clo&longs;'d at one end with <emph type="italics"/>Diachylon<emph.end type="italics"/> in&longs;tead <lb/>of an Hermetical Seal; we perceiv'd, that <lb/>upon the drawing of &longs;ome of the Air out <lb/>of the Receiver, the Mercury did indeed <lb/>begin to fall, but continu'd afterwards to <lb/>&longs;ub&longs;ide, though we did not continue pum­<lb/>ping. </s> <s>Whence it appear'd, that though <lb/>the <emph type="italics"/>Diachylon<emph.end type="italics"/> that &longs;topt the end of the <lb/>Tube were &longs;o thick and &longs;trong, that the <lb/>external Air could not pre&longs;s it in (as expe­<lb/>rience taught us that it would have done, <lb/>if there had been but little of it) yet the <lb/>&longs;ubt'ler parts of it were able (though <lb/>&longs;lowly) to in&longs;inuate them&longs;elves through <lb/>the very body of the Plai&longs;ter, which it <lb/>&longs;eems was of &longs;o clo&longs;e a Texture, as that <lb/>which we mention'd our &longs;elves to have <lb/>&longs;ucce&longs;sfully made u&longs;e of in the Experi­<lb/>ment <emph type="italics"/>De Vacuo<emph.end type="italics"/> &longs;ome years ago. </s> <s>So that <lb/>now we begin to &longs;u&longs;pect, that perhaps one <lb/>Rea&longs;on, why we cannot perfectly pump <lb/>out the Air, may be, that when the Ve&longs;&longs;el <pb xlink:href="013/01/143.jpg" pagenum="113"/>is almo&longs;t empty, &longs;ome of the &longs;ubtler <lb/>parts of the external Air may, by the <lb/>pre&longs;&longs;ure of the Atmo&longs;phere, be &longs;train'd <lb/>through the very body of the <emph type="italics"/>Diachylon<emph.end type="italics"/><lb/>into the Receiver. </s> <s>But this is onely con­<lb/>jecture: </s></p><p type="main"> <s>Another Circum&longs;tance of our Expe­<lb/>riment was this, That, if (when the <lb/>Quick-&longs;ilver in the Tube was fallen low) <lb/>too much ingre&longs;s were, at the hole of the <lb/>Stop-cock, &longs;uddenly permitted to the ex­<lb/>ternal Air; it would ru&longs;h in with that vio­<lb/>lence, and bear &longs;o forcibly upon the &longs;ur­<lb/>face of the &longs;ubjacent Quick-&longs;ilver, that <lb/>it would impel it up into the Tube rudely <lb/>enough to endanger the breaking of the <lb/>Gla&longs;s. </s></p><p type="main"> <s>We formerly mention'd, that the <lb/>Quick-&longs;ilver did not in its de&longs;cent fall as <lb/>much at a time after the two or three fir&longs;t <lb/>ex&longs;uctions of the Air, as at the beginning: <lb/>For, having mark'd its &longs;everal Stages up­<lb/>on the Tube, we found, that at the fir&longs;t <lb/>&longs;uck it de&longs;cended an Inch and 3/8, and at the <lb/>&longs;econd an Inch and 1/8; and when the Ve&longs;­<lb/>&longs;el was almo&longs;t empty'd, it would &longs;carce at <lb/>one ex&longs;uction be drawn down above the <lb/>breadth of a Barly-corn. </s> <s>And indeed we <lb/>found it very difficult to mea&longs;ure in what <pb xlink:href="013/01/144.jpg" pagenum="114"/>proportion the&longs;e decrements of the Mer­<lb/>curial Cylinder did proceed: partly be­<lb/>cau&longs;e (as we have already intimated) the <lb/>Quick &longs;ilver was &longs;oon drawn below the <lb/>top of the Receiver: and partly becau&longs;e, <lb/>upon its de&longs;cent at each ex&longs;uction, it <lb/>would immediatly rea&longs;cend a little up­<lb/>wards; either by rea&longs;on of the leaking of <lb/>the Ve&longs;&longs;el at &longs;ome imperceptible hole or <lb/>other, or by rea&longs;on of the motion of <lb/>Re&longs;titution in the Air, which, being &longs;ome­<lb/>what compre&longs;t by the fall as well as weight <lb/>of the Quick &longs;ilver, would repell it a lit­<lb/>tle upwards, and make it vibrate a little up <lb/>and down, before they could reduce each <lb/>other to &longs;uch an <emph type="italics"/>Æquilibrium<emph.end type="italics"/> as both <lb/>might re&longs;t in. </s> <s>But though we could not <lb/>hitherto make ob&longs;ervations accurate e­<lb/>nough concerning the mea&longs;ures of the <lb/>Quick-&longs;ilver's de&longs;cent, to reduce them in­<lb/>to any <emph type="italics"/>Hypothe&longs;is,<emph.end type="italics"/> yet would we not di&longs;­<lb/>courage any from attempting it: &longs;ince, if it <lb/>could be reduc'd to a certainty, tis proba­<lb/>ble that the di&longs;covery would not be un­<lb/>u&longs;eful. </s></p><p type="main"> <s>And, to illu&longs;trate this matter a little <lb/>more, we will adde, That we made a &longs;hift <lb/>to try the Experiment in one of our above <lb/>mention'd &longs;mall Receivers, not containing <pb xlink:href="013/01/145.jpg" pagenum="115"/>a Quart; but that (agreeably to what we <lb/>formerly ob&longs;erved) we found it as difficult <lb/>to bring this to be quite empty as to eva­<lb/>cuate the greater; the lea&longs;t external Air <lb/>that could get in (and we could not po&longs;&longs;i­<lb/>bly keep it all perfectly out) &longs;ufficing in &longs;o <lb/>&longs;mall a Ve&longs;&longs;el to di&longs;play a con&longs;iderable <lb/>pre&longs;&longs;ure upon the &longs;urface of the Mercury, <lb/>and thereby hinder that in the Tube from <lb/>falling to a level with it. </s> <s>But this is remark­<lb/>able, that having two or three times try'd <lb/>the Experiment in that &longs;mall Ve&longs;&longs;el, upon <lb/>the very fir&longs;t Cylinder of Air that was <lb/>drawn out of the Receiver, the Mercury <lb/>fell in the Tube 18 Inches and a half, and <lb/>at another 19 Inches and a half. </s></p><p type="main"> <s>But, on this occa&longs;ion, I hold it not un­<lb/>fit to give Your Lord&longs;hip notice that I <lb/>hop'd, from the de&longs;cent of the Quick­<lb/>&longs;ilver in the Tube upon the fir&longs;t &longs;uck, to <lb/>derive this advantage: that I &longs;hould thence <lb/>be enabled to give a near gue&longs;s at the pro­<lb/>portion of force betwixt the pre&longs;&longs;ure of <lb/>the Air (according to its various &longs;tates, as <lb/>to Den&longs;ity and Rarefaction) and the gra­<lb/>vity of Quick-&longs;ilver, then hitherto has <lb/>been done. </s> <s>For in our Experiment there <lb/>are diver&longs;e things given, that may be <lb/>made u&longs;e of towards &longs;uch a di&longs;covery. <pb xlink:href="013/01/146.jpg" pagenum="116"/>For fir&longs;t we may know the capacity of the <lb/>Receiver wherein the Experiment is <lb/>made, &longs;ince, by filling it with water, we <lb/>may ea&longs;ily compute how many Quarts, or <lb/>Mea&longs;ures of any other denomination, it <lb/>contains of Air; which Air, when &longs;hut <lb/>up in the Ve&longs;&longs;el, may be &longs;uppo&longs;'d to have <lb/>a pre&longs;&longs;ure equal to that of the Atmo­<lb/>&longs;phere; &longs;ince it is able to keep the Quick­<lb/>&longs;ilver in the Tube from falling any lower <lb/>then it did in the free and open Air. </s> <s>Next <lb/>here is given us the capacity of the bra&longs;s <lb/>Cylinder empty'd by the drawing down <lb/>of the Sucker (its bore and height being <lb/>mention'd in the de&longs;cription of our Pump) <lb/>whereby we may come to know how <lb/>much of the Air contain'd in the Recei­<lb/>ver is drawn out at the fir&longs;t &longs;uck. </s> <s>And <lb/>we may al&longs;o ea&longs;ily define, either in weight <lb/>or cubick mea&longs;ures the Cylinder of <lb/>Quick-&longs;ilver that an&longs;wers to the Cy­<lb/>linder of Air lately mention'd (that <lb/>Mercuriall Cylinder being in our En­<lb/>gine computable by deducting from <lb/>the entire altitude or that Cylinder of <lb/>Quick-&longs;ilver, the altitude at which it re&longs;ts <lb/>upon the fir&longs;t ex&longs;uction.) But though, if <lb/>this Experiment were very watchfully <lb/>try'd in Ve&longs;&longs;els of &longs;everal &longs;izes, and the <pb xlink:href="013/01/147.jpg" pagenum="117"/>various de&longs;cents of the Quick-&longs;ilver com­<lb/>par'd among them&longs;elves, 'tis not impro­<lb/>bable that &longs;ome &longs;uch thing as we hop'd for <lb/>may thereby be di&longs;cover'd. </s> <s>Yet becau&longs;e <lb/>not onely the &longs;olid contents of as much <lb/>of the Gla&longs;s-tube as remains within the <lb/>concave &longs;urface of the Receiver, and <lb/>(which is more difficult) the varying con­<lb/>tents of the Ve&longs;&longs;el containing the Mer­<lb/>cury, and of as much of the Mercury it <lb/>&longs;elf as is not in the Tube, mu&longs;t be dedu­<lb/>cted out of the capacity of the Receiver; <lb/>but there mu&longs;t al&longs;o an allowance be made <lb/>for this, that the Cylinder that is empty'd <lb/>by the drawing down of the Sucker, and <lb/>comes to be fill'd upon the letting of the <lb/>Air out of the Receiver into it, is not &longs;o <lb/>repleni&longs;h'd with Air as the Receiver it &longs;elf <lb/>at fir&longs;t was: becau&longs;e there pa&longs;&longs;es no more <lb/>Air out of the Receiver into the Cylin­<lb/>der, then is requi&longs;ite to reduce the Air in <lb/>the cavity of the Cylinder, and in that of <lb/>the Receiver to the &longs;ame mea&longs;ure of dila­<lb/>tation: Becau&longs;e of the&longs;e (I &longs;ay) and &longs;ome <lb/>other difficulties that require more skill in <lb/>Mathematicks then I pretend to, and much <lb/>more lea&longs;ure then my pre&longs;ent occa&longs;ions <lb/>would allow me, I was willing to refer the <lb/>nicer con&longs;ideration of this matter to &longs;ome <pb xlink:href="013/01/148.jpg" pagenum="118"/>of our Learned and Acurate Mathema­<lb/>ticians, thinking it enough for me to have <lb/>given the Hint already &longs;ugge&longs;ted. </s></p><p type="main"> <s>For further confirmation of what hath <lb/>been delivered, we likewi&longs;e tryed the Ex­<lb/>periment in a Tube of le&longs;s then two foot <lb/>long: and, when there was &longs;o much Air <lb/>drawn out of the Ve&longs;&longs;el, that the remain­<lb/>ing Air was not able to counterballance <lb/>the Mercurial Cylinder, the Quick-&longs;ilver <lb/>in the Tube &longs;ub&longs;ided &longs;o vi&longs;ibly, that (the <lb/>Experiment being try'd in the little Ve&longs;­<lb/>&longs;el lately mention'd) at the fir&longs;t &longs;uck it <lb/>fell above a &longs;pan, and was afterwards <lb/>drawn lower and lower for a little while; <lb/>and the external Air being let in upon it, <lb/>impell'd it up again almo&longs;t to the top of <lb/>the Tube: So little matters it how heavy <lb/>or light the Cylinder of Quick &longs;ilver to <lb/>&longs;ub&longs;ide is, provided its gravity over­<lb/>power the pre&longs;&longs;ure of as much external <lb/>Air as bears upon the &longs;urface of that Mer­<lb/>cury into which it is to fall. </s></p><p type="main"> <s>La&longs;tly we al&longs;o ob&longs;erv'd, That if (when <lb/>the Mercury in the Tube had been drawn <lb/>down, and by an Ingre&longs;s permitted to the <lb/>external Air, impell'd up again to its for­<lb/>mer height) there were &longs;ome more Air <lb/>thru&longs;t up by the help of the Pump into <pb xlink:href="013/01/149.jpg" pagenum="119"/>the Receiver, the Quick-&longs;ilver in the Tube <lb/>would a&longs;cend much above the wonted <lb/>height of 27 digits, and immediatly up­<lb/>on the letting out of that Air would fall a­<lb/>gain to the height it re&longs;ted at before. </s></p><p type="main"> <s>Your Lord&longs;hip will here perhaps expect, <lb/>that as tho&longs;e who have treated of the <emph type="italics"/>Tor­<lb/>ricellian<emph.end type="italics"/> Experiment, have for the mo&longs;t <lb/>part maintaind the Affirmative, or the Ne­<lb/>gative of that famous Que&longs;tion, Whether <lb/>or no that Noble Experiment infer a <emph type="italics"/>Va­<lb/>cuum?<emph.end type="italics"/> &longs;o I &longs;hould on this occa&longs;ion inter­<lb/>po&longs;e my Opinion touching that Contro­<lb/>ver&longs;ie, or at lea&longs;t declare whether or no, in <lb/>our Engine, the ex&longs;uction of the Air do <lb/>prove the place de&longs;erted by the Air &longs;uck'd <lb/>out, to be truly empty, that is, devoid of <lb/>all Corporeal Sub&longs;tance. </s> <s>But be&longs;ides that, <lb/>I have neither the lei&longs;ure, nor the ability, <lb/>to enter into a &longs;olemn Debate of &longs;o nice a <lb/>Que&longs;tion; Your Lord&longs;hip may, if you <lb/>think it worth the trouble, in the Dia­<lb/>logues not long &longs;ince referr'd to, finde the <lb/>Difficulties on both &longs;ides repre&longs;ented; <lb/>which then made me yield but a very wa­<lb/>vering a&longs;&longs;ent to either of the parties con­<lb/>tending about the Que&longs;tion: Nor dare I <lb/>yet take upon me to determine &longs;o difficult <lb/>a Controver&longs;ie. </s></p><pb xlink:href="013/01/150.jpg" pagenum="120"/><p type="main"> <s>For on the one &longs;ide it appears, that not­<lb/>with&longs;tanding the ex&longs;uction of the Air, our <lb/>Receiver may not be de&longs;titute of all Bo­<lb/>dies, &longs;ince any thing placed in it, may be <lb/>&longs;een there; which would not be, if it <lb/>were not pervious to tho&longs;e Beams of <lb/>Light which rebounding from the &longs;een <lb/>Object to our eyes, affect us with the &longs;en&longs;e <lb/>of it: And that either the&longs;e Beams are <lb/>Corporeal Emanations from &longs;ome lucid <lb/>body, or el&longs;e at lea&longs;t the light they convey <lb/>doth re&longs;ult from the brisk Motion of &longs;ome <lb/>&longs;ubtle Matter, I could, if I mi&longs;take not, <lb/>&longs;ufficiently manife&longs;t out of the Dialogues <lb/>above-mention'd, if I thought your Lord­<lb/>&longs;hip could &longs;eriou&longs;ly imagine that Light <lb/>could be convey'd without, at lea&longs;t, having <lb/>(if I may &longs;o &longs;peak) a Body for its Ve­<lb/>hicle. </s></p><p type="main"> <s>By the &longs;ixteenth Experiment, it al&longs;o <lb/>appears that the clo&longs;ene&longs;s of our Receiver <lb/>hinders it not from admitting the Efflu­<lb/>via of the Load-&longs;tone; which makes it <lb/>very probable that it al&longs;o freely admits <lb/>the Magnetical &longs;teams of the Earth; con­<lb/>cerning which, we have in another Trea­<lb/>ti&longs;e endeavour'd to manife&longs;t that numbers <lb/>of them do always permeate our Air. </s></p><p type="main"> <s>But on the other &longs;ide it may be &longs;aid, <pb xlink:href="013/01/151.jpg" pagenum="121"/>That as for the &longs;ubtle Matter which makes <lb/>the Objects enclo&longs;ed in our evacuated Re­<lb/>ceiver, vi&longs;ible, and the Magnetical Efflu­<lb/>via of the Earth that may be pre&longs;um'd to <lb/>pa&longs;s thorow it, though we &longs;hould grant <lb/>our Ve&longs;&longs;el not to be quite devoyd of <lb/>them, yet we cannot &longs;o rea&longs;onably affirm <lb/>it to be repleni&longs;h'd with them, as we may <lb/>&longs;uppo&longs;e, that if they were gather'd toge­<lb/>ther into one place without Intervals be­<lb/>tween them, they would fill but a &longs;mall <lb/>part of the whole Receiver. </s> <s>As in the <lb/>thirteenth Experiment, a piece of Match <lb/>was incon&longs;iderable for its bulk, while&longs;t its <lb/>parts lay clo&longs;e together, that afterwards <lb/>(when the Fire had &longs;catter'd them into <lb/>&longs;moke) &longs;eem'd to repleni&longs;h all the Ve&longs;&longs;el. <lb/></s> <s>For (as el&longs;ewhere our Experiments have <lb/>demon&longs;trated) both Light and the Efflu­<lb/>via of the Load-&longs;tone, may be readily ad­<lb/>mitted into a Gla&longs;s, Hermetically &longs;eal'd, <lb/>though before their Admi&longs;&longs;ion, as full of <lb/>Air as hollow Bodies here below are wont <lb/>to be, &longs;o that upon the ex&longs;uction of the <lb/>Air, the large &longs;pace de&longs;erted by it, may <lb/>remain empty, notwith&longs;tanding the pre­<lb/>tence of tho&longs;e &longs;ubtle Corpu&longs;cles, by <lb/>which Lucid and Magnetical Bodies pro­<lb/>duce their effects. </s></p><pb xlink:href="013/01/152.jpg" pagenum="122"/><p type="main"> <s>And as for the Allegations above <lb/>mention'd, they &longs;eem to prove but that <lb/>the Receiver devoy'd of Air, <emph type="italics"/>May<emph.end type="italics"/> be re­<lb/>pleni&longs;h'd with &longs;ome &longs;uch Etherial Matter, <lb/>as &longs;ome Modern Naturali&longs;ts write of; but <lb/>not that it really <emph type="italics"/>is<emph.end type="italics"/> &longs;o. </s> <s>And indeed to me <lb/>it yet &longs;eems, that as to tho&longs;e &longs;paces which <lb/>the <emph type="italics"/>Vacui&longs;ts<emph.end type="italics"/> would have to be empty, be­<lb/>cau&longs;e they are manife&longs;tly devoid of Air; <lb/>and all gro&longs;&longs;er Bodies, the <emph type="italics"/>Pleni&longs;ts<emph.end type="italics"/> (if I <lb/>may &longs;o call them) do not prove that &longs;uch <lb/>&longs;paces are repleni&longs;h'd with &longs;uch a &longs;ubtle <lb/>Matter as they &longs;peak of, by any &longs;en&longs;ible <lb/>effects, or operations of it (of which di­<lb/>vers new Tryals purpo&longs;ely made, have not <lb/>yet &longs;hown me any) but onely conclude <lb/>that there mu&longs;t be &longs;uch a Body, becau&longs;e <lb/>there cannot be a Void. </s> <s>And the rea&longs;on <lb/>why there cannot be a Void, being by <lb/>them taken, not from any Experiments, <lb/>or <emph type="italics"/>Phænomena<emph.end type="italics"/> of Nature, that clearly and <lb/>particularly prove their <emph type="italics"/>Hypothe&longs;is,<emph.end type="italics"/> but <lb/>from their notion of a Body, who&longs;e Na­<lb/>ture, according to them, con&longs;i&longs;ting one­<lb/>ly in exten&longs;ion (which indeed &longs;eems the <lb/>property mo&longs;t e&longs;&longs;ential to, becau&longs;e in&longs;epa­<lb/>rable from a Body) to &longs;ay a &longs;pace devoid <lb/>of Body, is to &longs;peak in the School-mens <lb/>Phra&longs;e, a Contradiction <emph type="italics"/>in Adjecto:<emph.end type="italics"/> This <pb xlink:href="013/01/153.jpg" pagenum="123"/>rea&longs;on, I &longs;ay, being thus de&longs;um'd, &longs;eems <lb/>to make the Controver&longs;ie about a <emph type="italics"/>Vacu­<lb/>um,<emph.end type="italics"/> rather a Metaphy&longs;ical, then a Phy&longs;io­<lb/>logical Que&longs;tion; which therefore we &longs;hall <lb/>here no longer debate, finding it very dif­<lb/>ficult either to &longs;atisfie Naturali&longs;ts with <lb/>this Carte&longs;ian Notion of a Body, or to <lb/>manife&longs;t wherein it is erroneous, and &longs;ub­<lb/>&longs;titute a better in its &longs;tead. </s></p><p type="main"> <s>But though we are unwilling to exa­<lb/>mine any further the Inferences wont to <lb/>be made from the <emph type="italics"/>Torricellian<emph.end type="italics"/> Experi­<lb/>ment, yet we think it not impertinent to <lb/>pre&longs;ent Your Lord&longs;hip with a couple of <lb/>Adverti&longs;ements concerning it. </s></p><p type="main"> <s>Fir&longs;t, then if in trying the Experiment <lb/>here or el&longs;ewhere, you make u&longs;e of the <lb/>Engli&longs;h mea&longs;ures that Mathematicians <lb/>and Trade&longs;men are here wont to imploy, <lb/>You will, unle&longs;s you be forewarn'd of it, <lb/>be apt to &longs;u&longs;pect that tho&longs;e that have writ­<lb/>ten of the Experiment have been mi&longs;ta­<lb/>ken. </s> <s>For whereas men are wont gene­<lb/>rally to talk of the Quick-&longs;ilver's remain­<lb/>ing &longs;u&longs;pended at the heighth of between <lb/>&longs;ix or &longs;even and twenty Inches; we com­<lb/>monly ob&longs;erv'd, when divers years &longs;ince <lb/>we fir&longs;t were &longs;ollicitous about this Expe­<lb/>riment, that the Quick-&longs;ilver in the Tube <pb xlink:href="013/01/154.jpg" pagenum="124"/>re&longs;ted at about 29 Inches & an half above <lb/>the &longs;urface of the Re&longs;tagnant Quick-&longs;ilver <lb/>in the Ve&longs;&longs;el, which did at fir&longs;t both amaze <lb/>and perplex us, becau&longs;e though we held it <lb/>not improbable that the difference of the <lb/>gro&longs;&longs;er Engli&longs;h Air, and that of <emph type="italics"/>Italy<emph.end type="italics"/> and <lb/><emph type="italics"/>France,<emph.end type="italics"/> might keep the Quick-&longs;ilver from <lb/>falling quite as low in this colder, as in <lb/>tho&longs;e warmer Climates; yet we could <lb/>not believe that that difference in the Air <lb/>&longs;hould alone be able to make &longs;o great a one <lb/>in the heights of the Mercurial Cylinders; <lb/>and accordingly upon enquiry we found, <lb/>that though the various den&longs;ity of the <lb/>Air be not to be over-look'd in this Ex­<lb/>periment, yet the main Rea&longs;on why we <lb/>found the Cylinder of Mercury to con&longs;i&longs;t <lb/>of &longs;o many Inches, was this, That our <lb/>Engli&longs;h Inches are &longs;omewhat inferior in <lb/>length to the digits made u&longs;e of in Fo­<lb/>rein Parts, by the Writers of the Expe­<lb/>riment. </s></p><p type="main"> <s>The next thing I de&longs;ire Your Lord&longs;hip to <lb/>take notice of, is, That the heigth of the <lb/>Mercurial Cylinder is not wont to be <expan abbr="foũd">found</expan> <lb/>altogether &longs;o great as really it might <lb/>prove, by rea&longs;on of the negligence or in­<lb/>cogitancy of mo&longs;t that make the Experi­<lb/>ment. </s> <s>For often times upon the opening <pb xlink:href="013/01/155.jpg" pagenum="125"/>of the inverted Tube into the Ve&longs;&longs;ell'd <lb/>Mercury, you may ob&longs;erve a bubble of <lb/>Air to a&longs;cend from the bottom of the <lb/>Tube through the &longs;ub&longs;iding Quick-&longs;ilver <lb/>to the top; and almo&longs;t always you may, <lb/>if you look narrowly, take notice of a <lb/>multitude of &longs;mall bubbles all along the <lb/>in&longs;ide of the Tube betwixt the Quick­<lb/>&longs;ilver & the gla&longs;s: (not now to mention the <lb/>Particles of Air that lye conceal'd in the <lb/>very Body of the Mercury) Many of <lb/>which, upon the Quick-&longs;ilvers for&longs;aking <lb/>the upper part of the Tube, do break in­<lb/>to that de&longs;erted &longs;pace where they finde <lb/>little or no re&longs;i&longs;tance to their expanding <lb/>of them&longs;elves. </s> <s>Whether this be the rea­<lb/>&longs;on that upon the Application of warm <lb/>Bodies to the emptyed part of the Tube, <lb/>the &longs;ubjacent Mercury would be depre&longs;&longs;'d <lb/>&longs;omewhat lower, we &longs;hall not determine; <lb/>though it &longs;eem very probable, e&longs;pecially <lb/>&longs;ince we found that upon the application <lb/>of Linnen cloaths dipped in Water, to <lb/>the &longs;ame part of the Tube, the Quick­<lb/>&longs;ilver would &longs;omewhat a&longs;cend, as if the <lb/>cold had conden&longs;'d the Impri&longs;on'd Air, <lb/>that pre&longs;&longs;'d upon it, into a le&longs;&longs;er room. <lb/></s> <s>But that the de&longs;erted &longs;pace is not wont to <lb/>be totally devoid of Air, we were induc'd <pb xlink:href="013/01/156.jpg" pagenum="126"/>to think by &longs;everal Circum&longs;tances. </s> <s>For <lb/>when an eminent Mathematician, and ex­<lb/>cellent Experimenter, had taken great <lb/>pains and &longs;pent much time in accuratly fil­<lb/>ling up a Tube of Mercury, we found <lb/>that yet there remain'd &longs;tore of incon&longs;pi­<lb/>cuous bubbles, by inverting the Tube, <lb/>letting the Quick-&longs;ilver fall to its wonted <lb/>heighth; and by approaching (by de­<lb/>grees) a red hot Iron to the out-&longs;ide of the <lb/>Tube, over again&longs;t the upper part of the <lb/>Mercurial Cylinder, for hereby the little <lb/>unheeded bubbles, being mightily expan­<lb/>ded, a&longs;cended in &longs;uch numbers, and &longs;o fa&longs;t <lb/>to the de&longs;erted &longs;pace, that the upper part <lb/>of the Quick-&longs;ilver &longs;eem'd, to our wonder, <lb/>to boyl. </s> <s>We further ob&longs;erv'd, That in <lb/>the tryals of the <emph type="italics"/>Torricellian<emph.end type="italics"/> Experiment <lb/>we have &longs;een made by others, and (one <lb/>excepted) all our own, we never found that <lb/>upon the inclining of the Tube the Quick­<lb/>&longs;ilver would fully reach to the very top of <lb/>the &longs;eal'd end: which argued, that there <lb/>was &longs;ome Air retreated thither that kept <lb/>the Mercury out of the unrepleni&longs;h'd <lb/>&longs;pace. </s></p><p type="main"> <s>If Your Lord&longs;hip &longs;hould now demand <lb/>what are the be&longs;t expedients to hinder the <lb/>intru&longs;ion of the Air in this Experiment; <pb xlink:href="013/01/157.jpg" pagenum="127"/>we mu&longs;t an&longs;wer, That of tho&longs;e which are <lb/>ea&longs;ily intelligible without ocular demon­<lb/>&longs;tration, we can at pre&longs;ent &longs;ugge&longs;t upon <lb/>our own tryals no better then the&longs;e. </s> <s>Fir&longs;t, <lb/>at the open end of the Tube the Gla&longs;s <lb/>mu&longs;t not onely be made as even at the ed­<lb/>ges as you can, but it is very conveni­<lb/>ent (e&longs;pecially if the Tube be large) that <lb/>the bottom be every way bent inwards, <lb/>that &longs;o the Orifice, not much exceeding a <lb/>quarter of an Inch in Diameter, may be <lb/>the more ea&longs;ily and exactly &longs;topp'd by the <lb/>Experimenter's finger; between which <lb/>and the Quick-&longs;ilver, that there may be <lb/>no Air intercepted (as very often it hap­<lb/>pens that there is) it is requi&longs;ite that the <lb/>Tube be fill'd as full as po&longs;&longs;ibly it can be, <lb/>that the finger which is to &longs;top it, pre&longs;&longs;ing <lb/>upon the accumulated and protuberant <lb/>Mercury, may rather throw down &longs;ome, <lb/>then not finde enough exactly to keep out <lb/>the Air. </s> <s>It is al&longs;o an u&longs;eful and compen­<lb/>dious way not to fill the Tube at fir&longs;t <lb/>quite ful of Mercury, but to leave near the <lb/>top about a qnarter of an Inch empty; for <lb/>if you then &longs;top the open end with your <lb/>finger, and invert the Tube that quarter <lb/>of an Inch of Air will a&longs;cend in a great <lb/>bubble to the top, and in its pa&longs;&longs;age thi-<pb xlink:href="013/01/158.jpg" pagenum="128"/>ther, will gather up all the little bubbles, <lb/>and unite them with it&longs;elf into one great <lb/>one, &longs;o that if by reinverting the Tube <lb/>you let that bubble return to the open <lb/>end of it, you will have a much clo&longs;er Mer­<lb/>curial Cylinder then before, and need but <lb/>to adde a very little Quick-&longs;ilver more to <lb/>fill up the Tube exactly. </s> <s>And la&longs;tly, as for <lb/>tho&longs;e le&longs;&longs;er and incon&longs;picuous parcels of <lb/>Air which cannot this way be gleaned up, <lb/>You may endeavor before you invert the <lb/>Tube, to free the Quick-&longs;ilver from them <lb/>by &longs;haking the Tube, and gently knock­<lb/>ing on the out-&longs;ide of it, after every little <lb/>parcel of Quick-&longs;ilver which you pour in; <lb/>and afterwards, by forcing the &longs;mall la­<lb/>titant bubbles of Air to di&longs;clo&longs;e them­<lb/>&longs;elves and break, by imploying a hot Iron <lb/>in &longs;uch manner as we lately mention'd. </s> <s>I <lb/>remember that by carefully filling the <lb/>Tube, though yet it were not quite free <lb/>from Air, we have made the Mercurial <lb/>Cylinder reach to 30 Inches and above an <lb/>eighth, and this in a very &longs;hort Tube: <lb/>which we therefore mention, becau&longs;e we <lb/>have found, by experience, that in &longs;hort <lb/>Tubes a little Air is more prejudicial to <lb/>the Experiment then in long ones, where <lb/>the Air having more room to expand it <pb xlink:href="013/01/159.jpg" pagenum="129"/>&longs;elf, does le&longs;s potently pre&longs;s upon the &longs;ub­<lb/>jacent Mercury. </s></p><p type="main"> <s>And &longs;ince we are fallen upon the con&longs;i­<lb/>deration of the Altitude of the Mercurial <lb/>Cylinder, I mu&longs;t not conceal from Your <lb/>Lord&longs;hip an Experiment relating thereun­<lb/>to, which perhaps will &longs;et both You and <lb/>many of your Friends the <emph type="italics"/>Virtuo&longs;i<emph.end type="italics"/> a think­<lb/>ing; and, by di&longs;clo&longs;ing &longs;ome things a­<lb/>bout the Air or Atmo&longs;phere that have <lb/>&longs;carce hitherto been taken notice of, may <lb/>afford you &longs;ome hints conducive to a fur­<lb/>ther di&longs;covery of the &longs;ubject of this E­<lb/>pi&longs;tle. </s></p><p type="main"> <s>WE took a Gla&longs;s Tube, which, <lb/><arrow.to.target n="marg20"/><lb/>though it were not much above <lb/>three Foot long, we made choice of be­<lb/>cau&longs;e it was of a more then ordinarily <lb/>even thickne&longs;s. </s> <s>This we fill'd with Mer­<lb/>cury, though not with as much care as we <lb/>could, yet with &longs;omewhat more then is <lb/>wont to be u&longs;ed in making the <emph type="italics"/>Torricellian<emph.end type="italics"/><lb/>Experiment. </s> <s>Then, having according to <lb/>the manner inverted the Tube, and open'd <lb/>the mouth of it beneath the &longs;urface of <lb/>&longs;ome other Quick-&longs;ilver, that in the Tube <lb/>fell down to the wonted heigth, leaving, <pb xlink:href="013/01/160.jpg" pagenum="130"/>as is u&longs;ual, &longs;ome little Particles of Air in <lb/>the &longs;pace it de&longs;erted, as we ghe&longs;t by ob­<lb/>&longs;erving, that upon the Application of hot <lb/>Bodies to the upper part of the Tube, the <lb/>Quick-&longs;ilver would be a little depre&longs;&longs;'d. <lb/></s> <s>La&longs;tly, having put both the Tube and the <lb/>Ve&longs;&longs;el it lean'd on into a convenient <lb/>Wooden Frame, to keep them from mi&longs;­<lb/>chances: we plac'd that Frame in a Win­<lb/>dow within my Bed-chamber, that I might <lb/>both keep the Mercury from being &longs;tirr'd, <lb/>and have opportunity to watch from time <lb/>to time the <emph type="italics"/>Phænomena<emph.end type="italics"/> it was to exhibit. <lb/></s> <s>For the better di&longs;covery of which, when <lb/>the Quick-&longs;ilver both in the Tube and <lb/>&longs;ubjacent Ve&longs;&longs;el was perfectly at re&longs;t, we <lb/>took notice, by a mark made on the out­<lb/>&longs;ide of the Gla&longs;s, how high the included <lb/>Liquor then reach'd. </s></p><p type="margin"> <s><margin.target id="marg20"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 18.</s></p><p type="main"> <s>During &longs;everal Weeks that the Tube <lb/>was kept in that Window (which was very <lb/>rarely open'd) I had the opportunity to <lb/>ob&longs;erve, that the Quick-&longs;ilver did &longs;ome­<lb/>times faintly imitate the Liquor of a <lb/>Weather-gla&longs;s, &longs;ub&longs;iding a little in warm, <lb/>and ri&longs;ing a little in cold Weather, which <lb/>we a&longs;cribed to the greater or le&longs;&longs;er pre&longs;&longs;ure <lb/>of that little Air that remain'd at the top <lb/>of the Tube, expanded or conden&longs;'d by <pb xlink:href="013/01/161.jpg" pagenum="131"/>the heat or cold that affected the ambient <lb/>Air. </s> <s>But that which I was chiefly careful <lb/>to ob&longs;erve, was this, That oftentimes the <lb/>Quick-&longs;ilver did ri&longs;e and fall in the Tube, <lb/>and that very notably, without conforming <lb/>it &longs;elf to what is u&longs;ual in Weather-gla&longs;&longs;es, <lb/>who&longs;e Air is at the top, nay quite contrary <lb/>thereunto: for &longs;ometimes I ob&longs;erv'd it in <lb/>very cold weather (&longs;uch as this Winter has <lb/>already afforded us good &longs;tore of) to fall <lb/>down much lower then at other times, <lb/>when by rea&longs;on of the ab&longs;ence of both <lb/>Fro&longs;t, Snow, and &longs;harp Winds, the Air was <lb/>comparatively much warmer. </s> <s>And I fur­<lb/>ther ob&longs;erv'd, That &longs;ometimes the Quick­<lb/>&longs;ilver would for &longs;ome days together re&longs;t <lb/>almo&longs;t at the &longs;ame height; and at other <lb/>times again it would in the compa&longs;s of the <lb/>&longs;ame day con&longs;iderably vary its altitude, <lb/>though there appear'd no change either in <lb/>the Air abroad, or in the temper of the Air <lb/>within the Room (wherein was con&longs;tantly <lb/>kept a good Fire) nor in any thing el&longs;e, to <lb/>which either I, or &longs;ome eminently Learned <lb/>Men whom I then acquainted with the <lb/>Experiment, could rea&longs;onably impute <lb/>&longs;uch a change: E&longs;pecially con&longs;idering that <lb/>the &longs;pace wherein the Mercury wandred up <lb/>and down, within about five Weeks, a­<lb/>mounted to full two Inches, of which we <pb xlink:href="013/01/162.jpg" pagenum="132"/>found by our &longs;everal marks whereby we <lb/>had taken notice of its &longs;everal removes, that <lb/>it had <expan abbr="de&longs;c&etilde;ded">de&longs;cended</expan> about (9/16) of an Inch from the <lb/>place where it fir&longs;t &longs;etled, & the other Inch <lb/>and (7/16) it had a&longs;cended. </s> <s>And it &longs;eems pro­<lb/>bable that the height of the Mercurial Cy­<lb/>linder would have varied yet more, if the <lb/>Experiment had been made in the open <lb/>Air and in a long Tube, where the Parti­<lb/>cles of the Impri&longs;on'd Air, by having <lb/>more room to di&longs;play them&longs;elves in, <lb/>might not have had &longs;o &longs;trong a Spring to <lb/>work upon the Quick-&longs;ilver with. </s> <s>But for <lb/>want both of time and of a competent <lb/>quantity of Mercury (which was not to be <lb/>procur'd where we then happen'd to be) <lb/>we were unable to make any further try­<lb/>als: which therefore chiefly troubled us, <lb/>becau&longs;e we would gladly have try'd an in­<lb/>genious Experiment which was &longs;ugge&longs;ted <lb/>unto us by that excellent Mathematician <lb/>Mr. <emph type="italics"/>Wren,<emph.end type="italics"/> who being invited to name any <lb/>thing he would have us try touching the <lb/>pre&longs;&longs;ure of the Air, de&longs;ired us to ob&longs;erve <lb/>whether or no the Quick-&longs;ilver in a long <lb/>Tube would not a little vary its height ac­<lb/>cording to the Tides, e&longs;pecially about the <lb/>New and Full Moon, about which times <lb/>Mariners ob&longs;erve tho&longs;e great Flowings <lb/>and Ebbs of the Sea, that they call the <pb xlink:href="013/01/163.jpg" pagenum="133"/>Spring-Tides. </s> <s>For he &longs;agaciou&longs;ly and <lb/>plau&longs;ibly conjectur'd that &longs;uch ob&longs;ervati­<lb/>ons accurately made, would di&longs;cover the <lb/>truth or erroneou&longs;ne&longs;s of the <emph type="italics"/>Carte&longs;ian <lb/>Hypothe&longs;is<emph.end type="italics"/> concerning the Ebbing and <lb/>Flowing of the Sea: which <emph type="italics"/>Des Cartes<emph.end type="italics"/><lb/>a&longs;cribes to the greater pre&longs;&longs;ure made upon <lb/>the Air by the Moon, and the Intercur­<lb/>rent Ethereal Sub&longs;tance at certain times <lb/>(of the Day, and of the Lunary Moneth) <lb/>then at others. </s> <s>But in regard we found <lb/>the Quick-&longs;ilver in the Tube to move up <lb/>and down &longs;o uncertainly, by rea&longs;on, as it <lb/>&longs;eems, of accidental mutation in the Air; <lb/>I &longs;omewhat doubt whether we &longs;hall finde <lb/>the Altitude of the Quick-&longs;ilver to vary <lb/>as regularly as the Experiment is ingeni­<lb/>ou&longs;ly propo&longs;'d. </s> <s>The &longs;ucce&longs;s we &longs;hall (God <lb/>permitting us to make tryal of it) acquaint <lb/>Your Lord&longs;hip with; and in the mean <lb/>time take notice, that when we had occa­<lb/>&longs;ion to take the Tube out of the Frame <lb/>(after it had &longs;taid there part of <emph type="italics"/>November<emph.end type="italics"/><lb/>and part of <emph type="italics"/>December<emph.end type="italics"/>) a good Fire being <lb/>then in the room, becau&longs;e it was a Snowy <lb/>day, we found the Quick-&longs;ilver in the <lb/>Tube to be above the upper &longs;urface of <lb/>the &longs;ubjacent Mercury 29 Inches three <lb/>quarters. </s></p><pb xlink:href="013/01/164.jpg" pagenum="134"/><p type="main"> <s>If Your Lord&longs;hip &longs;hould now ask me <lb/>what are the true cau&longs;es of this varying al­<lb/>titude of the Mercurial Cylinder; I &longs;hould <lb/>not undertake to an&longs;wer &longs;o difficult a que­<lb/>&longs;tion, and &longs;hould venter to &longs;ay no more, <lb/>then that among divers po&longs;&longs;ible cau&longs;es to <lb/>which it may be a&longs;cribed, it would not be, <lb/>perhaps, ab&longs;urd to reckon the&longs;e that fol­<lb/>low. </s></p><p type="main"> <s>Fir&longs;t then we may con&longs;ider, that the Air <lb/>in the upper part of the Tube is much <lb/>more rarified, and therefore more weak <lb/>then the external Air, as may appear by <lb/>this among other things, That upon the in­<lb/>clining of the Tube the Quick-&longs;ilver will <lb/>readily a&longs;cend almo&longs;t to the very top of <lb/>it, and &longs;o take up eight or nine tenth parts, <lb/>and perhaps more of that &longs;pace which it <lb/>de&longs;erted before: which would not happen <lb/>if that whole &longs;pace had been full of unra­<lb/>rified Air, &longs;ince that (as tryal may ea&longs;ily <lb/>&longs;atisfie you) would not have &longs;uffer'd it <lb/>&longs;elf to be thru&longs;t into &longs;o narrow a room by <lb/>&longs;o weak a pre&longs;&longs;ure. </s> <s>So that although in <lb/>our Tube when the included Air was <lb/>heated, the Quick-&longs;ilver was &longs;omewhat <lb/>depre&longs;&longs;'d: Yet there is this difference be­<lb/>twixt &longs;uch a Tube and common Weather­<lb/>Gla&longs;&longs;es, that in the&longs;e the included and the <pb xlink:href="013/01/165.jpg" pagenum="135"/>ambient Air are in an <emph type="italics"/>Æquilibrium<emph.end type="italics"/> as to <lb/>pre&longs;&longs;ure, and the weight of the Water <lb/>that keeps them &longs;eparate is &longs;carce con&longs;i­<lb/>derable. </s> <s>Whereas in &longs;uch a Tube as we <lb/>are &longs;peaking of, the Air within is very <lb/>much more dilated then that without; and <lb/>'tis not &longs;o much the &longs;pring or re&longs;i&longs;tance <lb/>of the included Air, as the weight of the <lb/>Mercurial Cylinder it &longs;elf that hinders the <lb/>Quick-&longs;ilver from a&longs;cending higher; for <lb/>if we &longs;hould &longs;uppo&longs;e that de&longs;erted part of <lb/>the Tube perfectly devoid of Air, yet <lb/>would the Quick-&longs;ilver ri&longs;e but a little <lb/>higher in it, and be far from filling it, in <lb/>regard the outward Air would not be <lb/>able to impel up &longs;uch a weight much <lb/>higher: whereas it may, by our former <lb/>Experiments appear, that if all the Air in <lb/>the upper part of a Weather-Gla&longs;s were <lb/>away, the Water would be impell'd up to <lb/>the very top of it, though the Pipe were <lb/>above thirty Foot long. </s></p><p type="main"> <s>We may next con&longs;ider, that this ra­<lb/>rified Air at the upper part of our Tube <lb/>being exactly &longs;hut up betwixt the Gla&longs;s <lb/>and the Quick-&longs;ilver, it was &longs;carce &longs;ubject <lb/>to any di&longs;cernable alterations, &longs;ave tho&longs;e <lb/>it receiv'd from heat and cold. </s></p><pb xlink:href="013/01/166.jpg" pagenum="136"/><p type="main"> <s>And we may further con&longs;ider that yet <lb/>the external Air or Atmo&longs;phere is &longs;ubject <lb/>to many alterations, be&longs;ides them that <lb/>proceed from either of tho&longs;e Quali­<lb/>ties. </s></p><p type="main"> <s>For the Experiment that occa&longs;ion'd <lb/>this Di&longs;cour&longs;e, &longs;eems to make it proba­<lb/>ble enough that there may be &longs;trange <lb/>Ebbings and Flowings, as it were, in the <lb/>Atmo&longs;phere; or at lea&longs;t, that it may ad­<lb/>mit great and &longs;udden Mutations, either as <lb/>to its Altitude or its Den&longs;ity, from cau&longs;es, <lb/>as well unknown to us, as the effects are <lb/>unheeded by us. </s> <s>And that You may not <lb/>think that there is nothing in Nature but <lb/>our Experiment that agrees with this our <lb/>conjecture, we might put Your Lord&longs;hip <lb/>in minde of the Pains and Aches that are <lb/>often complain'd of by tho&longs;e that have <lb/>had great Wounds or Brui&longs;es, and that <lb/>doe pre&longs;age great Mutations in the Air <lb/>oftentimes, whil&longs;t to &longs;trong and healthy <lb/>Per&longs;ons no &longs;ign of any &longs;uch thing appears. <lb/></s> <s>And that is al&longs;o very memorable to this <lb/>purpo&longs;e, which I remember I have &longs;ome­<lb/>where read in a Book of the Ingenious <lb/><emph type="italics"/>Kircherus,<emph.end type="italics"/> who giving a pertinent admoni­<lb/>tion concerning the various refractions <lb/>that may happen in the Air, relates, That <pb xlink:href="013/01/167.jpg" pagenum="137"/>during his &longs;tay in <emph type="italics"/>Malta,<emph.end type="italics"/> he often &longs;aw <lb/>Mount <emph type="italics"/>Ætna,<emph.end type="italics"/> though the next day, not­<lb/>with&longs;tanding its being extreamly clear, he <lb/>could not &longs;ee it; adding, that <emph type="italics"/>Vintemillius,<emph.end type="italics"/><lb/>a very Learned Per&longs;on, did oftentimes, <lb/>from a Hill he names, behold the whole <lb/>I&longs;land he calls <emph type="italics"/>Luprica<emph.end type="italics"/> protuberant above <lb/>the Sea, though at other times, notwith­<lb/>&longs;tanding a clear Sky, he could not &longs;ee it. <lb/></s> <s>And though perhaps this may be in part a­<lb/>&longs;cribed to the various light & po&longs;ition of <lb/>the &longs;un, or to the various di&longs;po&longs;ition of the <lb/>Spectators eye, or peradventure to &longs;ome <lb/>other cau&longs;e; yet the mo&longs;t probable cau&longs;e <lb/>&longs;eems to be the differing Den&longs;ity of the <lb/>Air, occa&longs;ion'd by Exhalations capable to <lb/>increa&longs;e the refraction, and con&longs;equently <lb/>bring Beams to the Eye, which otherwi&longs;e <lb/>would not fall on it. </s> <s>We have likewi&longs;e <lb/>in another Treati&longs;e mention'd our having <lb/>often ob&longs;erv'd with Tele&longs;copes a plenty <lb/>of Steams in the Air, which without &longs;uch <lb/>a help would not be taken notice of, and <lb/>which as they were not at all times to be <lb/>&longs;een even through a Tele&longs;cope, &longs;o they <lb/>did &longs;ometimes, e&longs;pecially after a &longs;hower of <lb/>Rain, ha&longs;tily di&longs;appear: and when we <lb/>have vi&longs;ited tho&longs;e places that abound with <lb/>Mines, we have &longs;everal times been told <pb xlink:href="013/01/168.jpg" pagenum="138"/>by the Diggers, that even when the Sky <lb/>&longs;eem'd clear, there would not &longs;eldom &longs;ud­<lb/>denly ari&longs;e, and &longs;ometimes long continue, <lb/>a certain Steam (which they u&longs;ually call a <lb/>damp) &longs;o gro&longs;s and thick, that it would <lb/>oftentimes put out their very Candles, if <lb/>they did not &longs;ea&longs;onably prevent it. </s> <s>And <lb/>I think it will ea&longs;ily be granted, that the <lb/>a&longs;cen&longs;ion of &longs;uch Steams into this or that <lb/>part of the Air, and their mixing with it, <lb/>are very like to thicken it; as on the o­<lb/>ther &longs;ide either heat or the &longs;udden conden­<lb/>&longs;ation of the Air in another part of the At­<lb/>mo&longs;phere (to mention now no other cau­<lb/>&longs;es) are capable of rarifying it. </s></p><p type="main"> <s>Nor will it very much import the main <lb/>&longs;cope of our Di&longs;cour&longs;e, whether it be <lb/>&longs;uppo&longs;'d that the copious Steams the <lb/>earth &longs;ends into the air, thicken that part <lb/>of the Atmo&longs;phere that receives them, <lb/>and make it more heavy: Or that &longs;ome­<lb/>times the Fumes may a&longs;cend with &longs;uch ce­<lb/>lerity, that though the Air be thicken'd <lb/>yet they rather dimini&longs;h then encrea&longs;e its <lb/>gravitation, in regard that the quickne&longs;s <lb/>of their a&longs;cent, not onely keeps them <lb/>from gravitating them&longs;elves, but may <lb/>hinder the pre&longs;&longs;ing downwards of many <lb/>Aërial Corpu&longs;cles that they meet with in <pb xlink:href="013/01/169.jpg" pagenum="139"/>their way upwards. </s> <s>This, I &longs;ay, is of <lb/>no great importance to our pre&longs;ent Di&longs;­<lb/>cour&longs;e, &longs;ince either way the Terre&longs;trial <lb/>Steam may here and there con&longs;iderably <lb/>alter the gravity or pre&longs;&longs;ure of the At­<lb/>mo&longs;phere. </s></p><p type="main"> <s>Your Lord&longs;hip may al&longs;o be plea&longs;ed to <lb/>remember, That by our &longs;eventeenth Ex­<lb/>periment it appear'd that as when the Air <lb/>in the Receiver was expanded more then <lb/>ordinarily, the Quick-&longs;ilver in the Tube <lb/>did proportionably &longs;ub&longs;ide; &longs;o when the <lb/>Air in the &longs;ame Receiver was a little more <lb/>then ordinarily compre&longs;&longs;'d, it did impell <lb/>up the Quick-&longs;ilver in the Tube above <lb/>the wonted height of betwixt &longs;ix and &longs;e­<lb/>ven and twenty digits. </s></p><p type="main"> <s>And if to the&longs;e things we annex, that <lb/>for ought we can finde by tryals purpo&longs;e­<lb/>ly made, the degree of rarity or den&longs;ity <lb/>of the Air, &longs;hut up into our Receiver, does <lb/>not &longs;en&longs;ibly alter its temperature as to <lb/>cold or heat. </s> <s>It will not, I hope, appear <lb/>ab&longs;urd to conceive, That &longs;ince the Air, <lb/>included in the Tube, could but very faint­<lb/>ly hinder the a&longs;cent of the Quick-&longs;ilver, <lb/>or pre&longs;s it downwards, &longs;ince too that inclu­<lb/>ded Air could &longs;carce immediately receive <lb/>any &longs;en&longs;ible alteration, &longs;ave either by heat <pb xlink:href="013/01/170.jpg" pagenum="140"/>or cold. </s> <s>And &longs;ince al&longs;o that according to <lb/>the bare den&longs;ity or rarity of the Air in­<lb/>cumbent on the &longs;ubjacent Quick-&longs;ilver in <lb/>the Ve&longs;&longs;el, that in the Tube was impell'd <lb/>more or le&longs;s high; &longs;uch changes happen­<lb/>ing in the neighboring part of the out­<lb/>ward Air, either by the a&longs;cen&longs;ion of gro&longs;s <lb/>or copious exhalations, or by any other <lb/>cau&longs;e (of which there may be divers) as <lb/>were capable to make con&longs;iderable altera­<lb/>tions in the con&longs;i&longs;tence of the Air, as to <lb/>rarity and den&longs;ity, <emph type="italics"/>may<emph.end type="italics"/> be able propor­<lb/>tionably to alter the heighth of the <lb/>Quick-&longs;ilver: I rather &longs;ay, that &longs;uch alte­<lb/>rations <emph type="italics"/>may<emph.end type="italics"/> be, then that they <emph type="italics"/>are<emph.end type="italics"/> the <lb/>cau&longs;es of our <emph type="italics"/>Phænomenon,<emph.end type="italics"/> becau&longs;e I think <lb/>it &longs;ufficient, if I have propo&longs;'d conje­<lb/>ctures not altogether irrational about a <lb/>new My&longs;tery of Nature, touching which, <lb/>the chief thing I pretend to, is to give oc­<lb/>ca&longs;ion to the Curious to inquire further <lb/>into it then I have been yet able to do. </s></p><p type="main"> <s>THe &longs;ame Rea&longs;on that mov'd us to <lb/><arrow.to.target n="marg21"/><lb/>conclude, that by the drawing of the <lb/>Air out of the Receiver, the Mercury <lb/>would de&longs;cend in a Tube &longs;horter then &longs;ix <lb/>and twenty digits, induc'd us al&longs;o to ex-<pb xlink:href="013/01/171.jpg" pagenum="141"/>pect, that by the &longs;ame means Water <lb/>might be brought to &longs;ub&longs;ide in Gla&longs;s <lb/>Tubes of a moderate length, though by <lb/>the noble Experiment, &longs;aid to have been <lb/>accurately made in <emph type="italics"/>France<emph.end type="italics"/> by <emph type="italics"/>Mon&longs;ieur <lb/>Pa&longs;chal,<emph.end type="italics"/> we are informed that a Tube of <lb/>no le&longs;s then about two and thirty Foot, <lb/>was found requi&longs;ite to make the Experi­<lb/>ment <emph type="italics"/>De Vacuo<emph.end type="italics"/> &longs;ucceed with Water in­<lb/>&longs;tead of Quick-&longs;ilver: &longs;o tall a Cylinder <lb/>of that lighter Liquor, being, it &longs;eems, <lb/>requi&longs;ite to equal the weight of a Mercu­<lb/>rial Cylinder of &longs;ix or &longs;even and twenty <lb/>digits, and &longs;urmount the pre&longs;&longs;ure of the <lb/>Atmo&longs;phere. </s></p><p type="margin"> <s><margin.target id="marg21"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 19.</s></p><p type="main"> <s>We took then a Tube of Gla&longs;s, Her­<lb/>metically &longs;eal'd at one end, of about four <lb/>foot in length, and not very &longs;lender: This <lb/>at the open end we fill'd with common <lb/>Water, and then &longs;topt that end till we <lb/>had inverted the Tube, and open'd it be­<lb/>neath the &longs;urface of a quantity of the like <lb/>Water, contain'd in a &longs;omewhat deep and <lb/>&longs;lender Ve&longs;&longs;el. </s> <s>This Ve&longs;&longs;el, with the <lb/>Tube in it, was let down into the Recei­<lb/>ver, and the Receiver being clo&longs;'d up af­<lb/>ter the accu&longs;tom'd manner, the Pump was <lb/>&longs;et awork. </s></p><pb xlink:href="013/01/172.jpg" pagenum="142"/><p type="main"> <s>As much of the event as concerns our <lb/>pre&longs;ent purpo&longs;e, was this, That till a con­<lb/>&longs;iderable part of the Air was drawn out <lb/>of the Receiver, the Tube continu'd top­<lb/>full of Water as when it was put in, it be­<lb/>ing requi&longs;ite that a great part of the Air <lb/>formerly contain'd in the Receiver, &longs;hould <lb/>be drawn out, to bring the remaining <lb/>Air to an <emph type="italics"/>Æquilibrium<emph.end type="italics"/> with &longs;o &longs;hort and <lb/>light a Cylinder of Water. </s> <s>But when <lb/>once the Water began to fall in the Tube, <lb/>then each ex&longs;uction of Air made it de­<lb/>&longs;cend a little lower, though nothing near <lb/>&longs;o much as the Quick-&longs;ilver at the begin­<lb/>ning did in the Experiment formerly men­<lb/>tion'd. </s> <s>Nor did there appear &longs;o much <lb/>inequality in the &longs;paces tran&longs;mitted by <lb/>the Water in its de&longs;cent, as there did in <lb/>tho&longs;e ob&longs;erv'd in the fall of the Quick­<lb/>&longs;ilver, of which the cau&longs;e will &longs;carce &longs;eem <lb/>ab&longs;tru&longs;e to him that &longs;hall duly reflect up­<lb/>on what has been already deliver'd. </s> <s>And <lb/>whereas we drew down the Quick-&longs;ilver <lb/>in the Tube &longs;o far as to bring it within an <lb/>Inch of the &longs;urface of the other Quick­<lb/>&longs;ilver into which it was to fall; the lowe&longs;t <lb/>we were able to draw down the Water <lb/>was, by our conjecture, to about a Foot <pb xlink:href="013/01/173.jpg" pagenum="143"/>or more above the &longs;urface of that in the <lb/>Ve&longs;&longs;el; of which I know not whether it <lb/>will be needful to a&longs;&longs;ign &longs;o obvious a cau&longs;e <lb/>as that, though the little Air remaining <lb/>in the Receiver could not hinder a Cylin­<lb/>der of above an Inch high of Quick-&longs;ilver <lb/>from &longs;ub&longs;iding; yet it might very well <lb/>be able, by its pre&longs;&longs;ure, to countervail the <lb/>weight of a Cylinder of a Foot long or <lb/>more, of a Liquor &longs;o much le&longs;s ponderous <lb/>then Quick-&longs;ilver, as Water is. </s> <s>And in <lb/>fine, to conclude our Experiment, when <lb/>the Water was drawn down thus low, we <lb/>found, that by letting in the outward Air, <lb/>it might be immediately impell'd up a­<lb/>gain to the higher parts of the Tube. </s></p><p type="main"> <s>We will adde no more concerning this <lb/>Experiment, &longs;ave that having try'd it in <lb/>one of our &longs;mall Receivers, we ob&longs;erv'd, <lb/>That upon the fir&longs;t ex&longs;uction of the Air <lb/>the Water did u&longs;ually &longs;ub&longs;ide divers In­<lb/>ches, and at the &longs;econd (ex&longs;uction) fall <lb/>down much lower, &longs;ub&longs;iding &longs;ometimes <lb/>near two Foot; as al&longs;o that upon the let­<lb/>ting in of the Air from without, the Wa­<lb/>ter was impell'd up with very great ce­<lb/>lerity. </s></p><pb xlink:href="013/01/174.jpg" pagenum="144"/><p type="main"> <s>THat the Air has a notable Ela&longs;tical <lb/><arrow.to.target n="marg22"/><lb/>power (whence&longs;oever that proceeds) <lb/>we have, I &longs;uppo&longs;e, abundantly evinc'd, <lb/>and it begins to be acknowledg'd by the <lb/>eminente&longs;t Modern Naturali&longs;ts. </s> <s>But whe­<lb/>ther or no there be in Water &longs;o much as <lb/>a languid one, &longs;eems hitherto to have been <lb/>&longs;carce con&longs;ider'd, nor has been yet, for <lb/>ought I know, determin'd either way by <lb/>any Writer, which invited us to make the <lb/>following Experiment. </s></p><p type="margin"> <s><margin.target id="marg22"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 20.</s></p><p type="main"> <s>There was taken a great Gla&longs;s-bubble, <lb/>with a long neck; (&longs;uch as Chymi&longs;ts are <lb/>wont to call a Philo&longs;ophical Egg) which <lb/>being fill'd with common Water till the <lb/>Liquor reach'd about a &longs;pan above the <lb/>bubble, and a piece of Paper being there <lb/>pa&longs;ted on, was put un&longs;top'd into the Re­<lb/>ceiver, and then the Air was &longs;uck'd out <lb/>after the wonted manner. </s> <s>The event was <lb/>this, That a con&longs;iderable part of the Air, <lb/>pent up in the Receiver, was drawn out <lb/>before we di&longs;cern'd any expan&longs;ion of the <lb/>Water; but, continuing the labor of <lb/>pumping, the Water manife&longs;tly began to <lb/>a&longs;cend in the &longs;tem of the Gla&longs;s, and di­<lb/>vers bubbles loo&longs;ening them&longs;elves from <pb xlink:href="013/01/175.jpg" pagenum="145"/>the lower parts of the Ve&longs;&longs;el, made their <lb/>way through the Body of the Water, to <lb/>the top of it, and there brake into the <lb/>Receiver: And after the Water once ap­<lb/>pear'd to &longs;well, then at each time the Stop­<lb/>cock was turn'd to let out the air from the <lb/>Receiver into the Pump, the Water in the <lb/>Neck of the Gla&longs;s did &longs;uddenly ri&longs;e a­<lb/>bout the breadth of a Barly-corn in the <lb/>Neck of the Gla&longs;s, and &longs;o attain'd, by <lb/>degrees, to a con&longs;iderable height above <lb/>the mark formerly mention'd. </s> <s>And at <lb/>length (to make the expan&longs;ion of the Wa­<lb/>ter more evident) the outward Air was <lb/>&longs;uddenly let in, and the Water immedi­<lb/>ately &longs;ub&longs;ided and de&longs;erted all the &longs;pace it <lb/>had newly gain'd in the Gla&longs;s. </s></p><p type="main"> <s>And, on this occa&longs;ion, it will not per­<lb/>haps be ami&longs;s to acquaint Your Lord&longs;hip <lb/>here (though we have already mention'd <lb/>it in another Paper, to another purpo&longs;e) <lb/>with another Expedient that we made u&longs;e <lb/>of two or three years ago, to try whether <lb/>or no Water had a Spring in it. </s> <s>About <lb/>that time then, That Great and Learned <lb/>Promoter of Experimental Philo&longs;ophy <lb/>Dr. <emph type="italics"/>Wilkins,<emph.end type="italics"/> doing me the Honor to <lb/>come him&longs;elf, and bring &longs;ome of his in­<lb/>qui&longs;itive Friends to my Lodging, we <pb xlink:href="013/01/176.jpg" pagenum="146"/>there had in readine&longs;s a round and hollow <lb/>Ve&longs;&longs;el of Pewter, great enough to con­<lb/>tain two pounds of Water, and exactly <lb/>clo&longs;e every where, but at one little hole <lb/>where it was to be fill'd; then partly by <lb/>&longs;ucking out the Air, and partly by inject­<lb/>ing Water with a Syringe, it was (not <lb/>without &longs;ome difficulty) fill'd up to the <lb/>top; and that hole being plac'd directly <lb/>upwards, there was a little more Water <lb/>lei&longs;urely forc'd in by the Syringe. </s> <s>Upon <lb/>which, though the Ve&longs;&longs;el were permitted <lb/>to re&longs;t, and the hole kept in its former po­<lb/>&longs;ture, yet the compre&longs;&longs;'d Water lei&longs;urely <lb/>&longs;well'd above the Orifice of the hole, and <lb/>divers drops ran over along the &longs;ides of the <lb/>Ve&longs;&longs;el. </s> <s>After this, we cau&longs;'d a skilful Pew­<lb/>terer (who had made the Globe) to clo&longs;e <lb/>it up in our pre&longs;ence with Soder &longs;o exqui­<lb/>&longs;itely, that none &longs;u&longs;pected there was any <lb/>thing left in it be&longs;ides Water. </s> <s>And la&longs;t­<lb/>ly, the Ve&longs;&longs;el thus &longs;oder'd up, was wari­<lb/>ly and often &longs;truck in divers places with a <lb/>Wooden Mallet, and thereby was mani­<lb/>fe&longs;tly compre&longs;&longs; d, whereby the inclo&longs;ed <lb/>Water was crouded into le&longs;s room then it <lb/>had before: And thereupon when we took <lb/>a Needle, and with it and the Mallet per­<lb/>forated the Ve&longs;&longs;el, and drew out the <pb xlink:href="013/01/177.jpg" pagenum="147"/>Needle again; the Water (but in a very <lb/>&longs;lender Stream) was &longs;uddenly thrown af­<lb/>ter it into the Air, to the height of two <lb/>or three Feet. </s> <s>As for the other <emph type="italics"/>Phænome­<lb/>na<emph.end type="italics"/> of this Experiment, &longs;ince they belong <lb/>not to our pre&longs;ent purpo&longs;e, and are partly <lb/>mention'd in another of our Papers, we <lb/>&longs;hall, in&longs;tead of recording them here, give <lb/>this Adverti&longs;ement: That as evidently <lb/>as this Experiment, and that made in our <lb/>Receiver, &longs;eem to prove a power in the <lb/>Water to expand and re&longs;tore it &longs;elf after <lb/>compre&longs;&longs;ion; yet for a rea&longs;on to be met <lb/>with ere long, I judged it not &longs;afe to in­<lb/>fer that Conclu&longs;ion from the&longs;e Premi&longs;es, <lb/>till I had made &longs;ome of the following try­<lb/>als, to the mention of which I will there­<lb/>fore ha&longs;ten. </s></p><p type="main"> <s>TO di&longs;cover whether the Expan&longs;ion <lb/><arrow.to.target n="marg23"/><lb/>of the Water really proceeded <lb/>from an Ela&longs;tical power in the parts of <lb/>the Water it &longs;elf, we thought it requi&longs;ite <lb/>to try two things: The one, Whether or no <lb/>the Atmo&longs;phere gravitates upon Bodies <lb/>under Water; and the other, Whether <lb/>in ca&longs;e it do gravitate, the Intume&longs;cence <lb/>of the Water may not be a&longs;cribed to &longs;ome <pb xlink:href="013/01/178.jpg" pagenum="148"/>&longs;ub&longs;tance &longs;ubtler then it &longs;elf, re&longs;iding m­<lb/>it. </s> <s>In order to the &longs;atisfying my &longs;elf about <lb/>the fir&longs;t of the&longs;e, I intended to let down <lb/>into the Receiver a Ve&longs;&longs;el of Water, <lb/>wherein &longs;hould be immer&longs;'d a very &longs;mall <lb/>oyl'd Bladder, almo&longs;t devoid of Air, but <lb/>&longs;trongly ty'd up at the Neck with a &longs;tring, <lb/>and detain'd a little under Water by &longs;uch <lb/>a weight fa&longs;ten'd to that &longs;tring, as &longs;hould <lb/>ju&longs;t be able to keep the Bladder from <lb/>&longs;wimming, and no more. </s> <s>For I &longs;uppo&longs;'d, <lb/>that if when all things were thus order'd, <lb/>the Receiver were empty'd, in ca&longs;e there <lb/>were any &longs;uch pre&longs;&longs;ure of the Atmo&longs;phere <lb/>upon Water, as I was inclin'd to believe, <lb/>the Air within the Bladder, being upon the <lb/>ex&longs;uction of the Air within the Receiver, <lb/>freed from that pre&longs;&longs;ure, and being pre&longs;&longs;'d <lb/>onely by the &longs;mall weight of the in­<lb/>cumbent Water, would con&longs;iderably ex­<lb/>pand it &longs;elf; but whil'&longs;t we were prepa­<lb/>ring Bladders for this Experiment, there <lb/>occurr'd an ea&longs;ie way for the making at <lb/>once both the Di&longs;coveries I de&longs;ir'd. </s></p><p type="margin"> <s><margin.target id="marg23"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 21.</s></p><p type="main"> <s>We took then a Gla&longs;s Viol, containing <lb/>by ghe&longs;s a pound and &longs;ome ounces of <lb/>Water, this we fill'd top full, and then <lb/>we put into the Neck of it a Gla&longs;s Pipe <lb/>a pretty deal bigger then a Goo&longs;e Quill, <pb xlink:href="013/01/179.jpg" pagenum="149"/>open at both ends, and of divers Inches <lb/>in length: One end of this Pipe was &longs;o <lb/>put into the Neck of the Viol, as to reach <lb/>a little below it, and then was carefully <lb/>cemented thereto that no Air might get <lb/>into the Viol, nor no Water get out of <lb/>it, otherwi&longs;e then through the Pipe; and <lb/>then the Pipe being warily fill'd, about <lb/>half way up to the top, with more Wa­<lb/>ter, and a mark being pa&longs;ted over again&longs;t <lb/>the upper &longs;urface of the Liquor; the Viol <lb/>thus fitted with the Pipe, was, by &longs;trings <lb/>let down into the Receiver, and according <lb/>to the wonted manner exqui&longs;itely clo&longs;'d <lb/>up in it. </s></p><p type="main"> <s>This done, we began to Pump out the <lb/>Air, and when a pretty quantity of it had <lb/>been drawn away, the Water in the Pipe <lb/>began to ri&longs;e higher in the Pipe, at the <lb/>&longs;ides of which &longs;ome little bubbles di&longs;co­<lb/>ver'd them&longs;elves. </s> <s>After a little while <lb/>longer, the Water &longs;till &longs;welling, there <lb/>appear'd at the bottom of the Pipe a bub­<lb/>ble about the bigne&longs;s of a &longs;mall Pea, <lb/>which a&longs;cending through the Pipe to the <lb/>top of the Water, &longs;taid there awhile and <lb/>then broke; but the Pump being nimbly <lb/>ply'd, the expan&longs;ion of the Water &longs;o en­<lb/>crea&longs;'d, that quickly, getting up to the <pb xlink:href="013/01/180.jpg" pagenum="150"/>top of the Pipe &longs;ome drops of it be­<lb/>gan to run down along the out-&longs;ide of it, <lb/>which oblig'd us to forbear pumping a­<lb/>while, and give the Water leave to &longs;ub­<lb/>&longs;ide within le&longs;s then two Inches of the <lb/>bottom of the Pipe. </s> <s>After this the <lb/>Pump being again &longs;et at work, the bub­<lb/>bles began to a&longs;cend from the bottom <lb/>of the Pipe, being not all of a &longs;ize, but yet <lb/>&longs;o big, that e&longs;timating one with another, <lb/>they appear'd to be of the &longs;ize of the &longs;mal­<lb/>ler &longs;ort of Peas; and of the&longs;e we reckon'd <lb/>about &longs;ixty which came up one after ano­<lb/>ther, be&longs;ides &longs;tore of &longs;maller ones, of which <lb/>we made no reckoning: And at length, <lb/>growing weary of reckoning and pumping <lb/>too (becau&longs;e we found, that in &longs;pight <lb/>of all our pains and indu&longs;try, &longs;ome un­<lb/>di&longs;cern'd Leak or other in the Recei­<lb/>ver hinder'd us from being able to empty <lb/>it altogether) we thought fit to de&longs;i&longs;t for <lb/>that time. </s> <s>After tryal made of what o­<lb/>peration the external Air, being let in <lb/>upon the expanded Water, would have; <lb/>and accordingly turning the Key to let in <lb/>the Air, we &longs;aw, as we expected, that <lb/>the Water in the Pipe in a moment fell <lb/>down almo&longs;t to the bottom of it. </s></p><pb xlink:href="013/01/181.jpg" pagenum="151"/><p type="main"> <s>Now of this Experiment there are two <lb/>or three Circum&longs;tances yet to be men­<lb/>tion'd, which are no le&longs;s then tho&longs;e alrea­<lb/>dy recited, pertinent to our pre&longs;ent pur­<lb/>po&longs;e. </s></p><p type="main"> <s>In the fir&longs;t place then, when the great­<lb/>er part of the Air had been pump'd out of <lb/>the Receiver, the ri&longs;ing bubbles a&longs;cend­<lb/>ed &longs;o very &longs;lowly in the Pipe, that their <lb/>Progre&longs;s was &longs;carce di&longs;cernable; which <lb/>&longs;eem'd to proceed from this, That their <lb/>bigne&longs;s was &longs;uch, That they could not <lb/>&longs;ufficiently extend them&longs;elves in the <lb/>cavity of the Gla&longs;s, without pre&longs;&longs;ing <lb/>on both hands again&longs;t the &longs;ides of it, <lb/>whereby they became of more difficult <lb/>extru&longs;ion to the Water. </s> <s>And though it <lb/>may &longs;eem &longs;trange the&longs;e bubbles &longs;hould <lb/>be of any con&longs;iderable bulk, &longs;ince 'tis <lb/>like they con&longs;i&longs;ted of le&longs;&longs;er parcels of <lb/>the Air lurking in the Water, then tho&longs;e <lb/>that were vigorous enough to make their <lb/>way through long before them: yet they <lb/>were commonly much larger then before, <lb/>&longs;ome of them being equal in quantity to <lb/>four or five Peas: Whether this their in­<lb/>crea&longs;e of bulk proceeded from the greater <lb/>decrement of the pre&longs;&longs;ure of the Air, <pb xlink:href="013/01/182.jpg" pagenum="152"/>or from the Union of two or three of <lb/>tho&longs;e numerous bubbles which were then <lb/>generated below the bottom of the Pipe, <lb/>where we could not &longs;ee what was done a­<lb/>mong them. </s></p><p type="main"> <s>Another thing we noted in our bubbles <lb/>was, That whereas in ordinary ones the <lb/>Air, together with the thin film of Water <lb/>that inve&longs;ts and detains, is wont to &longs;well <lb/>above the &longs;urface of the Water it &longs;wims <lb/>on, and commonly to con&longs;titute Hemi&longs;­<lb/>pherical Bodies with it, the little parcels <lb/>of Air that came up after the Receiver <lb/>was pretty well empty'd, did not make <lb/>protuberant bubbles, but &longs;uch who&longs;e up­<lb/>per &longs;urface was either level with or be­<lb/>neath that of the Water, &longs;o that the up­<lb/>per &longs;urface being u&longs;ually &longs;omewhat con­<lb/>vex, the le&longs;s protuberant parts of it had <lb/>a pretty quantity of Water remaining a­<lb/>bove them. </s></p><p type="main"> <s>We al&longs;o further ob&longs;erv'd, That where­<lb/>as in the bubbles that fir&longs;t appear'd in <lb/>the Pipe, the a&longs;cending Air did, as in o­<lb/>ther common bubbles, make its way up­<lb/>wards, by dividing the Water through <lb/>which it pa&longs;&longs;'d, in tho&longs;e bubbles that ap­<lb/>pear'd at the latter end of our Experi­<lb/>ment, when the pre&longs;&longs;ure of the little ex-<pb xlink:href="013/01/183.jpg" pagenum="153"/>ternal Air, remaining in the Receiver, <lb/>was grown incon&longs;iderable, the a&longs;cending <lb/>parcels of Air having now little more <lb/>then the weight of the incumbent Water <lb/>to &longs;urmount, were able both &longs;o to expand <lb/>them&longs;elves as to fill up that part of the <lb/>Pipe which they pervaded, & by pre&longs;&longs;ing <lb/>every way again&longs;t the &longs;ides of it, to lift <lb/>upwards with them what Water they <lb/>found above them, without letting any <lb/>con&longs;iderable quantity glide down along <lb/>the &longs;ides of the Gla&longs;s: So that &longs;ometimes <lb/>we could &longs;ee a bubble thru&longs;t on before it <lb/>a whole Cylinder of Water of perhaps <lb/>an Inch high, and carry it up to the top <lb/>of the Pipe; though as we formerly no­<lb/>ted, upon the letting in the external Air, <lb/>the&longs;e tumid bubbles &longs;uddenly relap&longs;'d to <lb/>their former incon&longs;picuou&longs;ne&longs;s. </s></p><p type="main"> <s>All the&longs;e things laid together &longs;eem'd <lb/>&longs;ufficiently to confirm that, which the <lb/>con&longs;ideration of the thing it &longs;elf would <lb/>ea&longs;ily enough per&longs;wade, namely, That <lb/>the Air, and &longs;uch like Bodies being under <lb/>Water, may be pre&longs;&longs;'d upon as well by <lb/>the Atmo&longs;phere, as by the weight of the <lb/>incumbent Water it &longs;elf. </s></p><p type="main"> <s>Hence likewi&longs;e we may verifie what we <lb/>ob&longs;erv'd at the clo&longs;e of the foregoing <pb xlink:href="013/01/184.jpg" pagenum="154"/>Experiment, namely, That from the &longs;ole <lb/>&longs;welling of Water there recorded, it can­<lb/>not be &longs;o &longs;afely concluded that Water, <lb/>when freed from compre&longs;&longs;ion, is endowd <lb/>with an Ela&longs;tical power of expanding it <lb/>&longs;elf, &longs;ince thereby it appears that the In­<lb/>tume&longs;cence produc'd by that Experiment, <lb/>may (at lea&longs;t in great part) be a&longs;crib'd to <lb/>the numerous little bubbles which are <lb/>wont to be produc'd in Water, from <lb/>which the pre&longs;&longs;ure of the Atmo&longs;phere is <lb/>in great mea&longs;ure taken off. </s> <s>So apt are we <lb/>to be mi&longs;-led, even by Experiments them­<lb/>&longs;elves, into Mi&longs;takes, when either we con­<lb/>&longs;ider not that mo&longs;t Effects may proceed <lb/>from various Cau&longs;es, or minde onely tho&longs;e <lb/>Circum&longs;tances of our Experiment, which <lb/>&longs;eem to comply with our preconceiv'd <lb/><emph type="italics"/>Hypothe&longs;is<emph.end type="italics"/> or Conjectures. </s></p><p type="main"> <s>And hence it &longs;eems al&longs;o probable, that <lb/>in the Pores or invi&longs;ible little rece&longs;&longs;es of <lb/>Water it &longs;elf there lie commonly inter­<lb/>&longs;per&longs;'d many parcels of either Air, or at <lb/>lea&longs;t &longs;omething Analogous thereunto, al­<lb/>though &longs;o very &longs;mall that they have not <lb/>been hitherto &longs;o much as &longs;u&longs;pected to <lb/>lurk there. </s> <s>But if it be demanded how it <lb/>appears that there is inter&longs;per&longs;'d through <lb/>the Body of Water any &longs;ub&longs;tance thinner <pb xlink:href="013/01/185.jpg" pagenum="155"/>then it &longs;elf, and why that which produc'd <lb/>the bubbles above mention'd &longs;hould not <lb/>be re&longs;olutely &longs;aid to be nothing el&longs;e then <lb/>a more active and &longs;pirituous part of the <lb/>Water, we &longs;hall, in order to the Elucida­<lb/>tion of this matter, &longs;ubjoyn to what <lb/>was formerly deliver'd the following Ex­<lb/>periment. </s></p><p type="main"> <s>WE recited in our nineteenth Ex­<lb/>periment, how by drawing mo&longs;t <lb/><arrow.to.target n="marg24"/><lb/>of the Air out of the Receiver, we made <lb/>the Water &longs;ub&longs;ide by degrees in a Gla&longs;s <lb/>not four Foot long: We &longs;hall now adde, <lb/>that in the like Experiment made in &longs;uch <lb/>a Tube, or a greater, it may be ob&longs;erv'd, <lb/>That when the Water begins to fall, there <lb/>will appear &longs;tore of bubbles fa&longs;ten'd all a­<lb/>long to the &longs;ides of the Gla&longs;s; of which <lb/>bubbles, by the agitation of the Ve&longs;&longs;el <lb/>con&longs;equent upon pumping, there will ari&longs;e <lb/>good numbers to the top of the Water, <lb/>and there break; and as the Cylinder of <lb/>Water is brought to be lower and lower, <lb/>&longs;o the bubbles will appear more numerous <lb/>in that part of the Tube which the Water <lb/>yet fills; and the nearer the &longs;urface of the <lb/>Water, in its de&longs;cent, approaches to the&longs;e <pb xlink:href="013/01/186.jpg" pagenum="156"/>bubbles, the greater they will grow, be­<lb/>cau&longs;e having the le&longs;s weight and pre&longs;&longs;ure <lb/>upon them, the Expan&longs;ion of that Air <lb/>which makes them, can be the le&longs;s re&longs;i&longs;ted <lb/>by the pre&longs;&longs;ure of the incumbent Water <lb/>and Air; as &longs;eems probable from hence, <lb/>that upon the letting in a little external <lb/>Air, tho&longs;e bubbles immediately &longs;hrink. </s></p><p type="margin"> <s><margin.target id="marg24"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 22.</s></p><p type="main"> <s>It may indeed, as we lately intimated, <lb/>be conjectur'd, that the&longs;e bubbles pro­<lb/>ceed not &longs;o much from any Air pre-exi­<lb/>&longs;tent in the Water, and lurking in the <lb/>Pores of it, as from the more &longs;ubtle parts <lb/>of the Water it &longs;elf; which by the expan­<lb/>&longs;ion allow'd them upon the dimini&longs;h'd <lb/>pre&longs;&longs;ure of the ambient Bodies may gene­<lb/>rate &longs;uch bubbles. </s> <s>And indeed, I am not <lb/>yet &longs;o well &longs;atisfied that bubbles may not <lb/>(at lea&longs;t &longs;ometimes) have &longs;uch an Origina­<lb/>tion: but that which makes me &longs;u&longs;pect <lb/>that tho&longs;e in our tryals contain'd real Air <lb/>formerly latitant in the Pores of the Wa­<lb/>ter, is this, That upon the inletting of <lb/>the external Air, the Water was not <lb/>again impell'd to the very top of the <lb/>Tube whence it began to fall, but was <lb/>&longs;topt in its a&longs;cent near an Inch beneath <lb/>the top. </s> <s>And &longs;ince, if the upper part of <lb/>the Tube had been devoyd of any other <pb xlink:href="013/01/187.jpg" pagenum="157"/>then &longs;uch Ethereal matter as was &longs;ubtle <lb/>enough freely to penetrate the pores of <lb/>the Gla&longs;s, the external Air would have <lb/>been able to impel the Water to the top <lb/>of a Tube &longs;even or eight times as long as <lb/>ours was; The <emph type="italics"/>Phænomenon<emph.end type="italics"/> under con&longs;i­<lb/>deration &longs;eem'd manife&longs;tly to argue that <lb/>the many bubbles that broke at the top <lb/>of the Water did contain a real Air, <lb/>which, being collected into one place and <lb/>hinder'd by the top of the Gla&longs;s from re­<lb/>ceding, was able to with&longs;tand the pre&longs;&longs;ure <lb/>of the outward Air. </s> <s>As we &longs;ee that if <lb/>never &longs;o little Air remain in the Tube up­<lb/>on the making the Experiment <emph type="italics"/>De Vacuo<emph.end type="italics"/><lb/>with Quick-&longs;ilver, no inclining of the <lb/>Tube, though a long one, will enable a <lb/>Man to impel the Mercury up to the very <lb/>top, by rea&longs;on (as we formerly noted) <lb/>of the re&longs;i&longs;tance of the included Air, which <lb/>will not be compre&longs;&longs;'d beyond a certain <lb/>degree. </s></p><p type="main"> <s>But in order to a further Di&longs;covery what <lb/>our bubbles were, we will, on this occa­<lb/>&longs;ion, inform Your Lord&longs;hip that we try'd <lb/>the XIX<emph type="sup"/>th<emph.end type="sup"/> <emph type="italics"/>Experiment<emph.end type="italics"/> in one of our &longs;mall <lb/>Receivers, and &longs;ound, that upon the draw­<lb/>ing down of the Water, &longs;o many bubbles <lb/>di&longs;clo&longs;'d them&longs;elves and broke into the <pb xlink:href="013/01/188.jpg" pagenum="158"/>upper part of the Tube, that having after­<lb/>wards let in the external Air, the Water <lb/>was not thereby impell'd to the top of the <lb/>Tube (three Foot in length) within a lit­<lb/>tle more then half an Inch. </s> <s>And whe­<lb/>ther or no it were Air that po&longs;&longs;e&longs;&longs;'d that <lb/>&longs;pace at the top of the Tube which was <lb/>not fill'd with Water, we took this cour&longs;e <lb/>to examine. </s> <s>We drew the &longs;econd time <lb/>the Air out of the Receiver, and found, <lb/>that by rea&longs;on of the body that po&longs;&longs;e&longs;&longs;'d <lb/>the top of the Tube, we were able not <lb/>onely to make the Water in the Tube fall <lb/>to a level with the &longs;urface of the Water <lb/>in the Ve&longs;&longs;el: But al&longs;o (by plying the <lb/>Pump a little longer) a great way beneath <lb/>it: which &longs;ince it could not well be a&longs;crib'd <lb/>to the bare &longs;ub&longs;iding of the Water by rea­<lb/>&longs;on of its own weight, argued that the Wa­<lb/>ter was depre&longs;&longs;'d by the Air: which was <lb/>confirm'd by the Figure of the &longs;urface of <lb/>the Water in the Tube, which was much <lb/>more concave then that of Water in <lb/>Tubes of that bigne&longs;s u&longs;es to be. </s> <s>And <lb/>this further tryal (to adde that upon <lb/>the by) we made at the &longs;ame time, That <lb/>when the Water in the Pipe was drawn <lb/>down almo&longs;t as low as the Water without <lb/>it, we ob&longs;erv'd, that (though we de&longs;i&longs;ted <pb xlink:href="013/01/189.jpg" pagenum="159"/>from pumping) by the bare application <lb/>of a hand moderately warm to the de&longs;ert­<lb/>ed part of the Tube, the remaining Wa­<lb/>ter would be &longs;peedily and notably de­<lb/>pre&longs;&longs;'d. </s> <s>And having for a while held a <lb/>kindled Coal to the out&longs;ide of the Tube, <lb/>(the Pump being &longs;till unimploy'd, becau&longs;e <lb/>the Ve&longs;&longs;el chanced to hold extraordinarily <lb/>well) the Air was by the heat &longs;o far ex­<lb/>panded, that it quickly drave the Water <lb/>to the bottom of the Tube, which was <lb/>divers Inches beneath the &longs;urface of the <lb/>ambient Water. </s> <s>Whereby it appears (by <lb/>the &longs;ame way by which we formerly mea­<lb/>&longs;ur'd the dilatation of the Air) that the <lb/>Air, even when it is expanded to between <lb/>90 and 100 times, its extent will yet rea­<lb/>dily admit of a much further rarifaction <lb/>by heat. </s></p><p type="main"> <s>I con&longs;ider'd al&longs;o that in ca&longs;e the Bub­<lb/>bles we have been &longs;peaking of, were pro­<lb/>duc'd by the parcels of Air latitant in the <lb/>Water, that Air being now got together <lb/>to the top of the Tube, though the Air <lb/>were again drawn out of the Receiver, <lb/>the taking off its pre&longs;&longs;ure would not di&longs;­<lb/>clo&longs;e bubbles as before; and accordingly, <lb/>the Air being again pump'd out, the Wa­<lb/>ter in the Tube de&longs;cended as formerly: <pb xlink:href="013/01/190.jpg" pagenum="160"/>but for a great while we &longs;carce &longs;aw one <lb/>bubble appear, onely when the Receiver <lb/>had been very much exhau&longs;ted, and the <lb/>Water was fallen very low, there appear'd <lb/>near the bottom of the Tube, certain <lb/>little bubbles, which &longs;eem'd to con&longs;i&longs;t of <lb/>&longs;uch parcels of Air as had not, by rea&longs;on <lb/>of their &longs;malne&longs;s, got up to the top of <lb/>the Water, with the more bulkie and vi­<lb/>gorous ones. </s> <s>And that which is not in­<lb/>con&longs;iderable, is, That having, by letting <lb/>in the Air, forc'd up the Water into the <lb/>Tube, we could not perceive that it a&longs;­<lb/>cended nearer the top, though we per­<lb/>mitted the Engine to remain unimploy'd <lb/>for two or three Nights together, and <lb/>watch'd whether the Water would &longs;well <lb/>up and fill the Tube. </s> <s>And on this occa­<lb/>&longs;ion I remember, that having try'd &longs;uch an <lb/>Experiment as this with Quick-&longs;ilver in­<lb/>&longs;tead of Water, in a Tube of about a Foot <lb/>and a half long, wherein it might &longs;eem <lb/>more hopeful to e&longs;cape bubbles; yet up­<lb/>on the drawing down the Quick-&longs;ilver as <lb/>low as we could, and letting in the exter­<lb/>nal Air upon it, we found that &longs;ome lurk­<lb/>ing particles of Air were got up to the top <lb/>of the Tube, and hinder'd the Quick­<lb/>&longs;ilver from being forc'd up again &longs;o high. <pb xlink:href="013/01/191.jpg" pagenum="161"/>And though the Quick-&longs;ilver were by <lb/>this means brought to appear a very clo&longs;e <lb/>and lovely Metalline Cylinder, not inter­<lb/>rupted by inter&longs;per&longs;'d bubbles as before; <lb/>yet having cau&longs;'d the Air to be again <lb/>drawn out of the Receiver, I could per­<lb/>ceive &longs;everal little bubbles to di&longs;clo&longs;e <lb/>them&longs;elves, fa&longs;ten'd to the in&longs;ide of the <lb/>Tube, near the bottom of it; and having <lb/>purpo&longs;ely watch'd one or two of the chief­<lb/>e&longs;t, I had the plea&longs;ure to ob&longs;erve, that <lb/>though they grew bigger and bigger as <lb/>the &longs;urface of the Mercurial Cylinder fell <lb/>nearer and nearer to them, &longs;o as that at <lb/>length they &longs;well'd into a con&longs;picuous <lb/>bulk; yet upon the wary letting in the <lb/>Air upon them, they did not break, but <lb/>pre&longs;ently &longs;hrunk up into a littlene&longs;s that <lb/>render'd them incon&longs;picuous. </s></p><p type="main"> <s>Whence it &longs;eems very probable, if not <lb/>certain, that even in the clo&longs;e&longs;t and mo&longs;t <lb/>ponderous Liquors, and therefore much <lb/>more in Water, there may lurk undi&longs;cern­<lb/>able parcels of Air, capable, upon the <lb/>removal of the pre&longs;&longs;ure of the ambient <lb/>Air (though but in part) and that of the <lb/>Liquor wherein it lurks, to produce con­<lb/>&longs;picuous bubbles. </s> <s>And con&longs;equently, if <lb/>it &longs;eem inconvenient to admit an Ela&longs;tical <pb xlink:href="013/01/192.jpg" pagenum="162"/>power in the Water, it may be &longs;aid that <lb/>the &longs;welling of the compre&longs;&longs;'d Water in <lb/>the Pewter Ve&longs;&longs;el lately mention'd, and <lb/>the &longs;pringing up of the Water at the hole <lb/>made by the Needle, were not the effects <lb/>of any internal <emph type="italics"/>Elater<emph.end type="italics"/> of the Water, but <lb/>of the &longs;pring of the many little particles <lb/>of Air di&longs;per&longs;'d through that Water, and <lb/>acting upon it in their &longs;udden recovering <lb/>them&longs;elves to a greater extent, then that <lb/>to which a violent compre&longs;&longs;ion had re­<lb/>duc'd them. </s></p><p type="main"> <s>But though, from all the&longs;e particulars, <lb/>it &longs;eems manife&longs;t that the bubbles we have <lb/>been all this while treating of, were pro­<lb/>duc'd by &longs;uch a &longs;ub&longs;tance as may be pro­<lb/>perly enough call'd Air; yet till we &longs;hall <lb/>have had the opportunity of making <lb/>&longs;ome further tryals concerning the nature <lb/>of the Air, we &longs;hall not re&longs;olutely deter­<lb/>mine whether or no Air be a Primogenial <lb/>Body (if I may &longs;o &longs;peak) that cannot <lb/>now be generated or turn'd either into <lb/>Water or any other Body. </s> <s>Yet in the <lb/>mean while (becau&longs;e it is an important <lb/>Que&longs;tion, and if rightly determin'd, may <lb/>much conduce to the knowledge of the <pb xlink:href="013/01/193.jpg" pagenum="163"/>nature of the Air) We think it not unfit <lb/>to make a brief mention of &longs;ome of the <lb/>particulars which at pre&longs;ent occur to our <lb/>thoughts in favor of either part of the <lb/>Que&longs;tion. </s></p><p type="main"> <s>Fir&longs;t then, divers Naturali&longs;ts e&longs;teem the <lb/>Air (as well as other Elements) to be in­<lb/>generable and incorruptible. </s> <s>And rea&longs;ons <lb/>plau&longs;ible enough may be drawn to coun­<lb/>tenance this Opinion from the con&longs;idera­<lb/>tion of that permanency that ought to <lb/>belong to the corporeal Principles of o­<lb/>ther Bodies. </s></p><p type="main"> <s>Next, Experience may be pleaded to <lb/>the &longs;ame purpo&longs;e, for I have read of &longs;ome <lb/>who have in vain attempted to turn Air <lb/>into Water, or VVater into Air. </s></p><p type="main"> <s>The diligent <emph type="italics"/>Schottus<emph.end type="italics"/> tells us, That a­<lb/><arrow.to.target n="marg25"/><lb/>mong&longs;t the other rarities to be met with <lb/>in that great Repo&longs;itory of them, the <lb/><emph type="italics"/>Mu&longs;æum Kercherianum,<emph.end type="italics"/> there is a round <lb/>Gla&longs;s with a tapering Neck near half full <lb/>(as one may gue&longs;s by the Scheme he an­<lb/>nexes) of ordinary Spring-water, which <lb/>having been Hermetically &longs;hut up there <lb/>by <emph type="italics"/>Clavius<emph.end type="italics"/> the famous Geometrician, <lb/>The included water is to this day pre­<lb/>&longs;erv'd, not onely clear and pure, as if <lb/>it were but newly put in: But (as it &longs;eems) <pb xlink:href="013/01/194.jpg" pagenum="164"/>without (in the lea&longs;t) turning into Air, <lb/>notwith&longs;tanding its having been kept <lb/>there the&longs;e fifty years: For he tells us, <lb/>That the Water hath continued there all <lb/>this while without any diminution. </s></p><p type="margin"> <s><margin.target id="marg25"/><emph type="italics"/>Schottus <lb/><gap/><emph.end type="italics"/><lb/>Part 3. <lb/>Cla&longs;&longs;. </s> <s>1.</s></p><p type="main"> <s>Nor does it appear in tho&longs;e Gla&longs;&longs;es, <lb/>which for Chymical Experiments we u&longs;u­<lb/>ally clo&longs;e with <emph type="italics"/>Hermes<emph.end type="italics"/> his Seal (as they <lb/>call it) that the included Air does, during <lb/>its long Impri&longs;onment, notwith&longs;tanding <lb/>the alteration it receives from various de­<lb/>grees of heat, di&longs;cernably alter its nature. <lb/></s> <s>Whereas we plainly perceive in our Dige­<lb/>&longs;tions and Di&longs;tillations, that though it <lb/>may be rarified into invi&longs;ible Vapors, yet <lb/>it is not really chang'd into Air, but onely <lb/>divided by heat, and &longs;catter'd into very <lb/>minute parts, which meeting together in <lb/>the Alembick or in the Receiver, do pre­<lb/>&longs;ently return into &longs;uch Water as they con­<lb/>&longs;tituted before. </s> <s>And we al&longs;o &longs;ee, that <lb/>ev'n Spirit of Wine, and other &longs;ubtle and <lb/>fugitive Spirits, though they ea&longs;ily fly in­<lb/>to the Air, and mingle with it, do yet in <lb/>the Gla&longs;&longs;es of Chymi&longs;ts ea&longs;ily lay a&longs;ide <lb/>the di&longs;gui&longs;e of Air, and re&longs;ume the deve­<lb/>&longs;ted form of Liquors. </s> <s>And &longs;o volatile <lb/>Salts, as of Urine, Harts-horn, <emph type="italics"/>&c.<emph.end type="italics"/> though <lb/>they will readily di&longs;per&longs;e them&longs;elves <pb xlink:href="013/01/195.jpg" pagenum="165"/>through the Air, and play up and down in <lb/>the capacity of an Alembick or a Recei­<lb/>ver: yet will they, after a while, fa&longs;ten <lb/>them&longs;elves to the in&longs;ides of &longs;uch Gla&longs;&longs;es <lb/>in the form of Salts. </s></p><p type="main"> <s>Be&longs;ides, &longs;ince Air is confe&longs;&longs;edly en­<lb/>dow'd with an Ela&longs;tical power that proba­<lb/>bly proceeds from its Texture, it appears <lb/>not what it is that in &longs;uch light alterations <lb/>of Water, as are by many pre&longs;um'd ca­<lb/>pable of turning it into Air, can be rea­<lb/>&longs;onably &longs;uppo&longs;'d &longs;o to contrive the Parti­<lb/>cles of Water, as to give them, and that <lb/>permanently, the &longs;tructure requi&longs;ite to a <lb/>Spring. </s> <s>I adde the word, Permanently, <lb/>becau&longs;e the newly mention'd ob&longs;ervations <lb/>&longs;eem to argue the Corpu&longs;cles of Air to <lb/>be irreducible into Water, whereas the <lb/>Aqueous Particles may perhaps for a <lb/>while be &longs;o vehemently agitated, as to <lb/>pre&longs;s almo&longs;t like Springs upon other Bo­<lb/>dies; yet upon the cea&longs;ing of the agitati­<lb/>on, they quickly, by relap&longs;ing into Wa­<lb/>ter, di&longs;clo&longs;e them&longs;elves to have been no­<lb/>thing el&longs;e whil'&longs;t they counterfeited the <lb/>Air. </s></p><p type="main"> <s>La&longs;tly, The Experiment formerly made <lb/>in our Engine with a piece of Match, <lb/>&longs;eems to evince, that even tho&longs;e light and <pb xlink:href="013/01/196.jpg" pagenum="166"/>&longs;ubtle Fumes (for the mo&longs;t part not aque­<lb/>ous neither) into which the Fire it &longs;elf <lb/>&longs;hatters dry Bodies, have no &longs;uch Spring <lb/>in them as the Air, &longs;ince they were unable <lb/>to hinder or repre&longs;s the expan&longs;ion of the <lb/>Air included in the Bladder they &longs;urroun­<lb/>ded. </s></p><p type="main"> <s>I remember indeed that the Learned <lb/><arrow.to.target n="marg26"/><lb/><emph type="italics"/>Fo&longs;ephus Aco&longs;ta,<emph.end type="italics"/> in his Hi&longs;tory of the <lb/><emph type="italics"/>We&longs;t Indies,<emph.end type="italics"/> tells us, That he &longs;aw in tho&longs;e <lb/>parts &longs;ome Grates of Iron &longs;o ru&longs;ted and <lb/>con&longs;um'd by the Air, that the Metal be­<lb/>ing pre&longs;&longs;'d between the Fingers, di&longs;&longs;olv'd <lb/>(to u&longs;e his words) to powder, as if it had <lb/>been Hay or parched Straw. </s> <s>And I re­<lb/><arrow.to.target n="marg27"/><lb/>member too, that the accurate <emph type="italics"/>Varenius<emph.end type="italics"/><lb/>tells us, That in the I&longs;lands commonly <lb/>called <emph type="italics"/>Azores,<emph.end type="italics"/> the Air (and Wind) is &longs;o <lb/>&longs;harp, that in a &longs;hort time it frets not only <lb/>Iron Plates, but the very Tiles upon the <lb/>Roofs of Hou&longs;es, and reduces them to <lb/>du&longs;t. </s> <s>And I have el&longs;ewhere mention'd <lb/>&longs;ome recent Ob&longs;ervations of this kinde. <lb/></s> <s>But it may be &longs;aid, That the above-men­<lb/>tion'd Authors a&longs;cribe the recited effects <lb/>chiefly to the Winds, and that however <lb/>the corro&longs;ion of the Iron and the Tiles <lb/>may proceed not from the Air it &longs;elf, or <lb/>any of its genuine parts, but from &longs;ome <pb xlink:href="013/01/197.jpg" pagenum="167"/>&longs;aline Corpu&longs;cles di&longs;per&longs;'d through the <lb/>Air, and driven by the Winds again&longs;t the <lb/>Bodies it is pre&longs;um'd to fret. </s> <s>And that <lb/>&longs;uch volatile Salts may copiou&longs;ly a&longs;cend <lb/>into the Air, and yet retain their Nature, <lb/>as doth the more fixt Salt in the Sea Wa­<lb/>ter, the &longs;ublimations of <emph type="italics"/>Sal-Armoniack<emph.end type="italics"/><lb/>may &longs;ufficiently evince. </s> <s>Not to mention <lb/>that I have &longs;hown &longs;ome Friends a &longs;ecret <lb/>kinde of &longs;aline Sub&longs;tance incomparably <lb/>&longs;ubtler then <emph type="italics"/>Sal-Armoniack,<emph.end type="italics"/> which did <lb/>not onely ea&longs;ily enough a&longs;cend it &longs;elf, but <lb/>carried up with it (and that in a very great <lb/>proportion) the &longs;olid and ponderous Bo­<lb/>dy ev'n of uncalcin'd Gold in the form of <lb/>&longs;ubtle exhalations, which did afterwards <lb/>fa&longs;ten them&longs;elves to the upper parts of <lb/>the Ve&longs;&longs;els, and yet manife&longs;t them&longs;elves <lb/>to continue Gold. </s> <s>We remember al&longs;o, <lb/>that to try whether Water could be turn'd <lb/>into Air, we once took an <emph type="italics"/>Æolipile,<emph.end type="italics"/> into <lb/>which we had before convey'd &longs;ome Wa­<lb/>ter, and placing it upon kindled Coals <lb/>when the heat forc'd out a vehement <lb/>&longs;tream of aqueous Vapors; we ty'd about <lb/>the neck of it, that of a Bladder, which <lb/>we had before empty'd of Air; and find­<lb/>ing the <emph type="italics"/>Æolipile<emph.end type="italics"/> after a while to blow up <lb/>the Bladder, we carefully ty'd it again <pb xlink:href="013/01/198.jpg" pagenum="168"/>that the included &longs;ub&longs;tance might not get <lb/>away. </s> <s>Then &longs;lipping it off from the <emph type="italics"/>Æo­<lb/>lipile<emph.end type="italics"/> we convey'd it into our Receiver, to <lb/>try whether or no that which in part di­<lb/>&longs;tended the Bladder would appear by its <lb/>Spring to be true Air: whereby we found <lb/>that upon the ex&longs;uction of the ambient <lb/>Air, the included &longs;ub&longs;tance expanded it <lb/>&longs;elf and the Bladder to a very much great­<lb/>er bulk then it was of before. </s> <s>And for <lb/>further &longs;atisfaction, having again taken <lb/>out the Bladder, we &longs;uffer'd it to remain <lb/>ty'd up till next morning, to try whether <lb/>time, and the coldne&longs;s of the night, would <lb/>make the contain'd &longs;ub&longs;tance relap&longs;e in­<lb/>to Water: But the next Morning we <lb/>found it little le&longs;s tumid then before. </s> <s>I <lb/>remember, I &longs;ay, that I once made this <lb/>Experiment; but I might &longs;ay in an&longs;wer <lb/>to it, that the chief rea&longs;on of my men­<lb/>tioning it, is, To let Your Lord&longs;hip &longs;ee <lb/>how requi&longs;ite it is to be circum&longs;pect and <lb/>con&longs;iderate, when we are to make and to <lb/>build upon nice Experiments. </s> <s>For though <lb/>I may &longs;eem to have u&longs;ed &longs;ufficient cauti­<lb/>on, yet afterward con&longs;idering with my <lb/>&longs;elf that the <emph type="italics"/>Æolipile<emph.end type="italics"/> I had imploy'd was <lb/>a very large one, and that it required much <lb/>more care then one that has not try'd it <pb xlink:href="013/01/199.jpg" pagenum="169"/>would imagine, to drive out all the Air <lb/>from a large <emph type="italics"/>Æolipile,<emph.end type="italics"/> I ea&longs;ily &longs;u&longs;pected <lb/>that the di&longs;ten&longs;ion of the Bladder in our <lb/>pneumatical Ve&longs;&longs;el, might proceed not <lb/>from the Watery &longs;teams that came out at <lb/>the narrow mouth of the <emph type="italics"/>Æolipile,<emph.end type="italics"/> and <lb/>had very much wetted the Bladder, but <lb/>from the rarified Air which in that &longs;ort of <lb/>Ve&longs;&longs;els is wont for a good while together <lb/>to come out with the rarified Water: and <lb/>accordingly having reiterated the Experi­<lb/>ment I found it very difficult (by rea­<lb/>&longs;on of the &longs;hrinking of the Bladders (up­<lb/>on their being heated) and of other impe­<lb/>diments) to make it &longs;o accurately as to de­<lb/>duce from it, that Water may be rarified <lb/>into true Air. </s></p><p type="margin"> <s><margin.target id="marg26"/><emph type="italics"/>Natural & <lb/><gap/> Hi&longs;t. <lb/><gap/> In­<lb/><gap/>,<emph.end type="italics"/> Lib. 3. <lb/><gap/> 9.</s></p><p type="margin"> <s><margin.target id="marg27"/><emph type="italics"/>Geogr. </s> <s>Ge­<lb/><gap/>ral.<emph.end type="italics"/></s><s> Lib. <lb/><gap/> 19.</s></p><p type="main"> <s>Again&longs;t the four other above-mention'd <lb/>Con&longs;iderations, we cannot &longs;pend time to <lb/>frame Objections, but mu&longs;t forth with <lb/>proceed to the mention of tho&longs;e things <lb/>that &longs;eem to argue that Air (at lea&longs;t &longs;uch <lb/>as produc'd our bubbles) maybe gene­<lb/>rated of Water and other Bodies. </s></p><p type="main"> <s>Fir&longs;t then we have found by Experi­<lb/>ence that a vapid Air, or Water rarified <lb/>into vapor, may at lea&longs;t for a while emu­<lb/>late the ela&longs;tical power of that which is <lb/>generally acknowledg'd to be true Air. <pb xlink:href="013/01/200.jpg" pagenum="170"/>For if you take a good <emph type="italics"/>Æolipile,<emph.end type="italics"/> with a <lb/>moderately &longs;trong and &longs;lender Neck, and <lb/>filling it with Water, lay it upon quick <lb/>Coals, you may after a while ob&longs;erve &longs;o <lb/>great a pre&longs;&longs;ure by &longs;ome of the parts con­<lb/>tain'd in the <emph type="italics"/>Æolipile<emph.end type="italics"/> upon others, that <lb/>the Water will &longs;ometimes be thrown up <lb/>into the Air above three or four Foot <lb/>high; and if you then take the <emph type="italics"/>Æolipile<emph.end type="italics"/><lb/>almo&longs;t red hot from off the Fire, you may <lb/>perceive that the Water will for a longer <lb/>time then one would ea&longs;ily imagine con­<lb/>tinue to be &longs;pouted out in a violent <lb/>Stream. </s> <s>And if there remains but little <lb/>Water in the <emph type="italics"/>Æolipile<emph.end type="italics"/> when tis taken ve­<lb/>ry hot from the Fire, immerfing the <lb/>Neck of it into cold Water, you will <lb/>finde, that after it begins to &longs;uck in &longs;ome <lb/>Water, there will be made from time to <lb/>time &longs;tore of large bubbles in that Water <lb/>where into the neck was plunged. </s> <s>Which <lb/>bubbles &longs;eem manife&longs;tly to proceed from <lb/>hence, that for a while the heat in the <emph type="italics"/>Æ­<lb/>olipile<emph.end type="italics"/> continues &longs;trong enough to rarifie <lb/>part of the Water that is &longs;uck'd in, and <lb/>expel it in the form of Vapors through <lb/>the Water incumbent on the Pipe. </s> <s>If al­<lb/>&longs;o when the <emph type="italics"/>Æolipile<emph.end type="italics"/> is almo&longs;t full of wa­<lb/>ter, and therefore can contain but little <pb xlink:href="013/01/201.jpg" pagenum="171"/>Air; you hold a Coal or Brand in that <lb/>&longs;tream of Vapors that i&longs;&longs;ues out of the <lb/>narrow mouth of it, you will finde this <lb/>vapid or rorid Air, (if I may &longs;o call it) <lb/>to blow the Fire very &longs;trongly and with a <lb/>roaring noi&longs;e. </s> <s>And that it be not &longs;aid <lb/>that 'tis by the external Air which the a­<lb/>queous &longs;teams drive before them, and <lb/>not by the Steams them&longs;elves, that the <lb/>Bla&longs;t is made and the Flame excited; it <lb/>has been ob&longs;erv'd, that by approaching <lb/>the Coal or Brand almo&longs;t to the mouth <lb/>of the <emph type="italics"/>Æolipile,<emph.end type="italics"/> the winde appear'd more <lb/>vehement then if the Body to be kindled <lb/>were held &longs;ome Inches off. </s></p><p type="main"> <s>But in regard the ela&longs;tical power of the <lb/>Stream, i&longs;&longs;uing out of an <emph type="italics"/>Æolipile,<emph.end type="italics"/> &longs;eems <lb/>manife&longs;tly due to the heat that expands <lb/>and agitates the aqueous Particles where­<lb/>of that Stream con&longs;i&longs;ts, and that &longs;uch <lb/>rapid winds &longs;eem to be but water &longs;catter'd <lb/>into little parts and &longs;et a moving; &longs;ince <lb/>we finde, that holding a Knife, or any <lb/>&longs;olid, &longs;mooth and clo&longs;e Body again&longs;t the <lb/>&longs;tream that i&longs;&longs;ues out of the Æolipile, the <lb/>vapors conden&longs;ing upon it, will pre&longs;ently <lb/>cover it with water: It will be very per­<lb/>tinent to &longs;ubjoyn a notable Experiment <lb/>that I remember I have met with in the <pb xlink:href="013/01/202.jpg" pagenum="172"/>de&longs;cription given us by the Indu&longs;trious <lb/><emph type="italics"/>Kircher,<emph.end type="italics"/> of &longs;everal Mu&longs;ical Engines. </s> <s>And <lb/>(though it may &longs;eem &longs;omewhat prolix) <lb/>we will recite what he delivers in his own <lb/>words, which are the&longs;e. </s></p><p type="main"> <s><emph type="italics"/>Cum codem tempore quo hæc &longs;crip&longs;i<emph.end type="italics"/><lb/><arrow.to.target n="marg28"/><lb/><emph type="italics"/>&longs;ummi Pont: Innocentii<emph.end type="italics"/> X<emph type="sup"/>mi<emph.end type="sup"/> <emph type="italics"/>mandato or­<lb/>gani hydraulici in horto Quirinali con&longs;ti­<lb/>tuendi cur a mihi commendata e&longs;&longs;et; Æoliam <lb/>camer am in&longs;igni &longs;ane &longs;ucce&longs;&longs;u con&longs;trui ju&longs;si­<lb/>mus, eá quæ &longs;equitur ratione.<emph.end type="italics"/></s></p><p type="margin"> <s><margin.target id="marg28"/><emph type="italics"/>Kirch: Art: <lb/>Mag: Con: <lb/>& Di&longs;&longs;on: <lb/>lib.<emph.end type="italics"/> 9. <lb/>p. 309.</s></p><p type="main"> <s><emph type="italics"/>Erat longitudo &longs;ive altitudo cameræ<emph.end type="italics"/> AH <lb/>5 <emph type="italics"/>Pedum, Latitudine<emph.end type="italics"/> 3 <emph type="italics"/>fere ex lateribus<emph.end type="italics"/><lb/><arrow.to.target n="marg29"/><lb/><emph type="italics"/>con&longs;tructa; in medio duo tenebat Diaphrag­<lb/>mata<emph.end type="italics"/> CD <emph type="italics"/>&<emph.end type="italics"/> EJ <emph type="italics"/>in modum cribri pluri­<lb/>bus for aminibus pertu&longs;a. </s> <s>Paulo infra ca­<lb/>nalis<emph.end type="italics"/> G <emph type="italics"/>aquam advehens in&longs;erebatur in<emph.end type="italics"/> H <lb/><emph type="italics"/>eidem epi&longs;tomium par ab at exitum. </s> <s>Aqua <lb/>it áque per canalem<emph.end type="italics"/> G <emph type="italics"/>maximo impetu ruens <lb/>vehementi&longs;simum ventum mox intus exci­<lb/>t ab at; qui ventus nimia humiditate imbu­<lb/>tus, ut purior exiret &longs;iccior&queacute;, Diaphrag­<lb/>mata ill a in cribri modum pertu&longs;a, or dinata <lb/>&longs;unt. </s> <s>Intra hæc enim aquæ vehemens agi­<lb/>tatio rupta fracta&queacute; aerem puriorem per<emph.end type="italics"/> A <lb/><emph type="italics"/>canalem &longs;ubtilioremque emittebat: Verum <lb/>cum po&longs;tea <expan abbr="inventũ">inventum</expan> &longs;it <expan abbr="aer&etilde;">aerem</expan> plus æquo <expan abbr="humi-dũ">humi­<lb/>dum</expan> interioribus Organi meatibus <expan abbr="maximũ">maximum</expan> <lb/>detrimentum inferre: Hinc ut aer aquo&longs;us<emph.end type="italics"/><pb xlink:href="013/01/203.jpg" pagenum="173"/><emph type="italics"/>&longs;icci&longs;simam <expan abbr="cõ&longs;i&longs;tentiam">con&longs;i&longs;tentiam</expan> acquireret, ordina­<lb/>vimus canalem plumbeum<emph.end type="italics"/> QR <emph type="italics"/>in helicem <lb/>contortum va&longs;i<emph.end type="italics"/> S <emph type="italics"/>aliquantulum capaciori in <lb/>modum Urnæ efformato, in&longs;ertum. </s> <s>Intra <lb/>urnam enim plumbeam & canalem tortuo­<lb/>&longs;um illi&longs;us aer humidus, it a ab omni aquo&longs;i­<lb/>tate defæcabatur, ut ex furno in Organum <lb/>derivatus dici potuerit. </s> <s>Urna<emph.end type="italics"/> S <emph type="italics"/>canalis <lb/>tortuo&longs;us<emph.end type="italics"/> QR <emph type="italics"/>ultimum orificium<emph.end type="italics"/> Q <emph type="italics"/>in&longs;e­<lb/>ritur anemothecæ organi. </s> <s>Et hunc modum <lb/>organis hydraulicis <expan abbr="omniũ">omnium</expan> <expan abbr="apti&longs;simũ">apti&longs;simum</expan> reperi.<emph.end type="italics"/></s></p><p type="margin"> <s><margin.target id="marg29"/><emph type="italics"/>See the fif­<lb/>teenth Fi­<lb/>gure.<emph.end type="italics"/></s></p><p type="main"> <s><emph type="italics"/>Debet autem cameræ illa &longs;ituari in loco <lb/>quantum fieri pote&longs;t &longs;icciori it a ut longo ca­<lb/>nali aqua intr a eam derivetur ne locus hu­<lb/>miditate &longs;ua Organis officiat.<emph.end type="italics"/></s></p><p type="main"> <s>Thus far the Ingenious <emph type="italics"/>Kircherus,<emph.end type="italics"/> whom <lb/>I the rather cite, becau&longs;e although I have <lb/>been informed of divers Ventiducts (as <lb/>they call them) by very knowing Tra­<lb/>vellers that have ob&longs;erv'd them: Yet this <lb/>relation of our Author being very pun­<lb/>ctual, and deliver'd upon his own particu­<lb/>lar Experience, has, I confe&longs;s, made me <lb/>wi&longs;h I had had the good fortune when I <lb/>was at <emph type="italics"/>Rome,<emph.end type="italics"/> to take notice of the&longs;e Or­<lb/>gans; or that I had now the opportunity <lb/>of examining of &longs;uch an Experiment. <lb/></s> <s>For if upon a &longs;trict inquiry I &longs;hould find <lb/>that the breath that blows the Organs <pb xlink:href="013/01/204.jpg" pagenum="174"/>does not really upon the cea&longs;ing of its un­<lb/>u&longs;ual agitation by little and little relap&longs;e <lb/>into water, I &longs;hould &longs;trongly &longs;u&longs;pect that <lb/>'tis po&longs;&longs;ible for Water to be ea&longs;ily turn'd <lb/>into Air. </s> <s>I remember indeed, that we <lb/>have formerly taught that there lurks an <lb/>inter&longs;per&longs;ed Air in the pores of ordinary <lb/>Water, which may po&longs;&longs;ibly be &longs;truck out <lb/>by the breaking of the Water in its fall <lb/>into the Æolian Chamber, (as he calls it.) <lb/>But in regard the Scheme &longs;eems to repre­<lb/>&longs;ent that Chamber as clo&longs;ely &longs;hut, and <lb/>thereby forbids us to &longs;uppo&longs;e that any Air <lb/>is carried into it but what is latitant in the <lb/>Water, it will &longs;carce &longs;eem probable to <lb/>him who remembers how &longs;mall a propor­<lb/>tion of Air, that appear'd to be when its <lb/>rarification &longs;ea&longs;ed, which was conceal'd in <lb/>the Water we freed from bubbles in our <lb/>Receiver, that &longs;o little Air as is common­<lb/>ly di&longs;per&longs;'d through Water, &longs;hould be a­<lb/>ble, in &longs;o little Water as was requi&longs;ite for <lb/>&longs;o &longs;mall a room, to make &longs;o vehement a <lb/>Wind as our Author here tells us of. </s> <s>I <lb/>have &longs;ometime therefore &longs;u&longs;pected, that <lb/>in this ca&longs;e the Wind may be produc'd by <lb/>&longs;mall particles of the water it &longs;elf, forci­<lb/>bly expell'd out of the Chamber into the <lb/>Organs. </s> <s>And to the Objection to which <pb xlink:href="013/01/205.jpg" pagenum="175"/>I fore&longs;aw this ghe&longs;s to be liable, namely, <lb/>That, no heat intervening, there appear'd <lb/>nothing that &longs;hould rai&longs;e the Water into <lb/>exhalations and give them an impul&longs;e. </s> <s>I <lb/>thought it might be &longs;aid that motion a­<lb/>lone, if vehement enough, may, with­<lb/>out &longs;en&longs;ible heat, &longs;uffice to break Water <lb/>into very minute parts, and make them a&longs;­<lb/>cend upwards, if they can no where el&longs;e <lb/>more ea&longs;ily continue their agitation. </s> <s>For <lb/>Iremember, that Travelling betwixt <emph type="italics"/>Ly­<lb/>ons<emph.end type="italics"/> and <emph type="italics"/>Geneva,<emph.end type="italics"/> I &longs;aw, not very far out of <lb/>the Way, a place where the River of <lb/><emph type="italics"/>Rhone<emph.end type="italics"/> coming &longs;uddenly to be &longs;treighten'd <lb/>betwixt two Rocks, &longs;o near each other, <lb/>that a Man may (if my Memory fail me <lb/>not) &longs;tand a&longs;tride upon both at once: that <lb/>rapid Stream da&longs;hing with great impetuo­<lb/>&longs;ity again&longs;t its Rocky Boundaries, does <lb/>break part of its Water into &longs;uch minute <lb/>Corpu&longs;cles, and put them into &longs;uch a mo­<lb/>tion, that Pa&longs;&longs;engers ob&longs;erve at a good di­<lb/>&longs;tance off, as it were a Mi&longs;t ari&longs;ing from <lb/>that place, and a&longs;cending a good way up <lb/>into the Air. </s> <s>Such, I &longs;ay, was my &longs;u&longs;­<lb/>picion touching the Wind we have been <lb/>con&longs;idering, but it &longs;eems &longs;omething odde <lb/>that aqueous Vapors &longs;hould, like a dry <lb/>Wind, pa&longs;s through &longs;o long and tortu-<pb xlink:href="013/01/206.jpg" pagenum="176"/>ous a Pipe of Lead, as that de&longs;crib'd by <lb/>our Author, &longs;ince we &longs;ee in the Heads of <lb/>Stills, and the Necks of <emph type="italics"/>Æolipiles,<emph.end type="italics"/> how <lb/>quickly &longs;uch vapors are even by a very lit­<lb/>tle cold reconden&longs;ed into Water. </s> <s>But <lb/>to this al&longs;o &longs;omething may be &longs;peciou&longs;ly <lb/>reply'd; wherefore contenting my &longs;elf to <lb/>have mention'd our Authors Experiment <lb/>as a plau&longs;ible, though not demon&longs;trative <lb/>proof, that Water may be tran&longs;muted in­<lb/>to Air. </s> <s>We will pa&longs;s on to mention in <lb/>the third place another Experiment, which <lb/>we try'd in order to the &longs;ame enquiry. </s></p><p type="main"> <s>We took a clear Gla&longs;s bubble (capable <lb/>of containing by ghe&longs;s about three Oun­<lb/>ces of Water) with a Neck &longs;omewhat <lb/>long and wide, of a Cylindrical form; <lb/>this we fill'd with Oyl of Vitriol and fair <lb/>water, of each almo&longs;t a like quantity, and <lb/>ca&longs;ting in half a dozen &longs;mall Iron Nails, <lb/>we &longs;topt the mouth of the Gla&longs;s (which <lb/>was top-full of Liquor) with a flat piece <lb/>of <emph type="italics"/>Diapalma<emph.end type="italics"/> provided for the purpo&longs;e, <lb/>that accommodating it &longs;elf to the &longs;urface <lb/>of the water, the Air might be exqui­<lb/>&longs;itely excluded: and &longs;peedily inverting <lb/>the Viol, we put the Neck of it into a <lb/>&longs;mall wide-mouth'd Gla&longs;s that &longs;tood rea­<lb/>dy with more of the &longs;ame Liquor in it, to <pb xlink:href="013/01/207.jpg" pagenum="177"/>receive it. </s> <s>As &longs;oon as the neck had reach'd <lb/>the bottom of the Liquor it was dipp'd <lb/>into, there appear'd at the upper part <lb/>(which was before the bottom) of the <lb/>Viol a bubble, of about the bigne&longs;s of <lb/>a Pea, which &longs;eem'd rather to con&longs;i&longs;t of <lb/>&longs;mall and recent bubbles, produc'd by the <lb/>action of the di&longs;&longs;olving Liquor upon the <lb/>Iron, then any parcel of the external Air <lb/>that might be &longs;u&longs;pected to have got in <lb/>upon the inver&longs;ion of the Gla&longs;s, e&longs;peci­<lb/>ally &longs;ince we gave time to tho&longs;e little <lb/>Particles of Air which were carried down <lb/>with the Nails into the Liquor to fly up <lb/>again. </s> <s>But whence this fir&longs;t bubble was <lb/>produced, is not &longs;o material to our Expe­<lb/>riment, in regard it was &longs;o &longs;mall: For <lb/>&longs;oon after we perceiv'd the bubbles <lb/>produced by the action of the <emph type="italics"/>Men­<lb/>&longs;truum,<emph.end type="italics"/> upon the Metal a&longs;cending co­<lb/>piou&longs;ly to the bubble already named, and <lb/>breaking into it, did &longs;oon exceedingly in­<lb/>crea&longs;e it, and by degrees depre&longs;s the wa­<lb/>ter lower and lower, till at length the &longs;ub­<lb/>&longs;tance contain'd in the&longs;e bubbles po&longs;&longs;e&longs;&longs;ed <lb/>the whole cavity of the Gla&longs;s Viol, and <lb/>almo&longs;t of its Neck too, reaching much <lb/>lower in the Neck then the &longs;urface of the <lb/>ambient Liquor, wherewith the open­<lb/>mouth'd Gla&longs;s was by this means almo&longs;t <pb xlink:href="013/01/208.jpg" pagenum="178"/>repleni&longs;hed. </s> <s>And becau&longs;e it might be <lb/>&longs;u&longs;pected that the depre&longs;&longs;ion of the Li­<lb/>quor might proceed from the agitation <lb/>whereinto the exhaling and impri&longs;on'd <lb/>&longs;teams were put, by that heat which is <lb/>wont to re&longs;ult from that action of corro­<lb/>&longs;ive &longs;alts upon Metals, we &longs;uffered both <lb/>the Viol and the open-mouthed Gla&longs;s to <lb/>remain as they were, in a Window, for <lb/>three or four days and nights together; but <lb/>looking upou them &longs;everal times during <lb/>that while, as well as at the expiration of <lb/>it, the whole cavity of the Gla&longs;s bubble, <lb/>and mo&longs;t of its Neck, &longs;eem'd to be po&longs;­<lb/>&longs;e&longs;&longs;'d by Air, &longs;ince by its &longs;pring it was a­<lb/>ble for &longs;o long to hinder the expell'd and <lb/>ambient Liquor from regaining its former <lb/>place. </s> <s>And it was remarkable, that ju&longs;t <lb/>before we took the Gla&longs;s bubble out of <lb/>the other Gla&longs;s, upon the application <lb/>of a warm hand to the convex part of the <lb/>bubble; the Impri&longs;on'd &longs;ub&longs;tance readily <lb/>dilated it &longs;elf like Air, and broke through <lb/>the Liquor in divers bubbles, &longs;ucceeding <lb/>one another. </s></p><p type="main"> <s>Having al&longs;o another time try'd the like <lb/>Experiment with a &longs;mall Viol, and with <lb/>Nails di&longs;&longs;olv'd in <emph type="italics"/>Aquafortis,<emph.end type="italics"/> we found <lb/>nothing incongruous to what we have <lb/>now deliver'd. </s> <s>And this Circum&longs;tance <pb xlink:href="013/01/209.jpg" pagenum="179"/>we ob&longs;erv'd, that the newly generated <lb/>&longs;teams did not onely po&longs;&longs;e&longs;s almo&longs;t all the <lb/>whole cavity of the Gla&longs;s, but divers <lb/>times without the a&longs;&longs;i&longs;tance of the heat of <lb/>my hand, broke away in large bubbles <lb/>through the ambient Liquor into the o­<lb/>pen Air: So that the&longs;e Experiments <lb/>with corro&longs;ive Liquors, &longs;eem'd manife&longs;t­<lb/>ly enough to prove, though not that Air <lb/>may be generated out of the Water, yet <lb/>that in general air may be generated anew. </s></p><p type="main"> <s>La&longs;tly, to the foregoing Arguments <lb/>from Experience we might ea&longs;ily &longs;ubjoyn <lb/>the Authority of <emph type="italics"/>Ari&longs;totle,<emph.end type="italics"/> and of (his <lb/>followers) the Schools who are known to <lb/>have taught, that Air and Water being <lb/>Symbolizing Elements (in the quality of <lb/>moi&longs;ture) are ea&longs;ily tran&longs;mutable into one <lb/>another. </s> <s>But we &longs;hall rather to the fore­<lb/>going Argument adde this, drawn from <lb/>Rea&longs;on, That if, as <emph type="italics"/>Leucippus, Democri­<lb/>tus, Epieurus<emph.end type="italics"/> and others, follow'd by <lb/>divers modern Naturali&longs;ts, have taught, <lb/>the difference of Bodies proceeds but <lb/>from the various Magnitudes, Figures, <lb/>Motions, and Textures of the &longs;mall <lb/>parts they con&longs;i&longs;t of, (all the quali­<lb/>ties that make them differ, being de­<lb/>ducible from thence) there appeares <pb xlink:href="013/01/210.jpg" pagenum="180"/>no rea&longs;on why the minute parts of Wa­<lb/>ter, and other Bodies, may not be &longs;o agi­<lb/>tated or connected as to de&longs;erve the name <lb/>of Air. </s> <s>For if we allow the <emph type="italics"/>Carte&longs;ian <lb/>Hypothe&longs;is,<emph.end type="italics"/> according to which, as we no­<lb/>ted at the beginning of this Letter, the <lb/>Air may con&longs;i&longs;t of any terrene or aqueous <lb/>Corpu&longs;cles, provided they be kept &longs;wim­<lb/>ming in the interfluent Cele&longs;tial Matter; <lb/>it is obvious that Air may be as often ge­<lb/>nerated, as Terre&longs;trial Particles minute <lb/>enough to be carried up and down, by the <lb/>Cele&longs;tial Matter a&longs;cend into the Atmo­<lb/>&longs;phere. </s> <s>And if we will have the Air to <lb/>be a <emph type="italics"/>congeries<emph.end type="italics"/> of little &longs;lender Springs, it <lb/>&longs;eems not impo&longs;&longs;ible, though it be diffi­<lb/>cult, that the &longs;mall parts of divers Bo­<lb/>dies may by a lucky concour&longs;e of cau&longs;es <lb/>be &longs;o connected as to con&longs;titute &longs;uch <lb/>little Springs, &longs;ince (as we note in another <lb/>Treati&longs;e) Water in the Plants it nouri&longs;hes <lb/>is u&longs;ually contriv'd into Springy Bodies, <lb/>and even the bare alter'd po&longs;ition and con­<lb/>nexion of the parts of a Body may &longs;uf­<lb/>fice to give it a Spring that it had not be­<lb/>fore, as may be &longs;een in a thin and fiexible <lb/>Plate of Silver; unto which, by &longs;ome <lb/>&longs;troaks of a Hammer, you may give a <lb/>Spring, and by onely heating it red hot <pb xlink:href="013/01/211.jpg" pagenum="181"/>you may make it again flexible as be­<lb/>fore. </s></p><p type="main"> <s>The&longs;e, My Lord, are &longs;ome of the <lb/>Con&longs;iderations at pre&longs;ent occurring to <lb/>my thoughts, by which it may be made <lb/>probable that Air may be generated a­<lb/>new. </s> <s>And though it be not impo&longs;&longs;ible <lb/>to propo&longs;e Objections again&longs;t the&longs;e, as <lb/>well as again&longs;t what has been repre&longs;ented <lb/>in favor of the contrary Doctrine; yet <lb/>having already almo&longs;t tyr'd my &longs;elf, and <lb/>I fear more then almo&longs;t tyr'd Your Lord­<lb/>&longs;hip with &longs;o trouble&longs;ome an Enquiry af­<lb/>ter the Nature of bubbles, I &longs;hall wil­<lb/>lingly leave Your Lord&longs;hip to judge of <lb/>the Arguments alledged on either &longs;ide, <lb/>and I &longs;hould &longs;carce have ventur'd to enter­<lb/>tain You &longs;o long concerning &longs;uch empty <lb/>things as the Bubbles, which have occa­<lb/>&longs;ion'd all this Di&longs;cour&longs;e, but that I am <lb/>willing to invite You to take notice with <lb/>me of the ob&longs;curity of things, or the dim­<lb/>ne&longs;s of our created Intellects (which yet <lb/>of late too many &longs;o far pre&longs;ume upon, as <lb/>either to Deny or Cen&longs;ure the Almighty <lb/>and Omni&longs;cient Creator him&longs;elf) and to <lb/>learn hence this Le&longs;&longs;on, That there are <lb/>very many Things in Nature that we di&longs;­<lb/>dainfully over-look as obvious or de&longs;pi-<pb xlink:href="013/01/212.jpg" pagenum="182"/>cable, each of which would exerci&longs;e our <lb/>Under&longs;tandings, if not po&longs;e them too, if <lb/>we would but attentively enough con&longs;ider <lb/>it, and not &longs;uperficially contemplate, but <lb/>attempt &longs;atisfactorily to explicate the na­<lb/>ture of it. </s></p><p type="main"> <s>SInce the writing of the twenty one and <lb/><arrow.to.target n="marg30"/><lb/>twenty &longs;econd Experiments (and not­<lb/>with&longs;tanding all that hath been on their <lb/>occa&longs;ion deliver'd concerning bubbles) we <lb/>made &longs;ome further tryals in pro&longs;ecution <lb/>of the &longs;ame inquiry whereto they were <lb/>de&longs;igned. </s></p><p type="margin"> <s><margin.target id="marg30"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 23.</s></p><p type="main"> <s>We cho&longs;e then, among&longs;t tho&longs;e Gla&longs;&longs;es <lb/>which Chymi&longs;ts are wont to call Philo&longs;o­<lb/>phical Eggs, one that containing about <lb/>nine Ounces of Water, had a Neck of <lb/>half an Inch in Diameter at the top, and <lb/>as we ghe&longs;t, almo&longs;t an Inch at the bot­<lb/>tom; which breadth we pitch'd upon for <lb/>a rea&longs;on that will by and by appear: then <lb/>filling it with common Water to the <lb/>height of about a Foot and a half, &longs;o <lb/>that the upper part remain'd empty, we <lb/>&longs;hut it into the Receiver, and watch'd what <lb/>would follow upon pumping, which pro-<pb xlink:href="013/01/213.jpg" pagenum="183"/>ved that a great part of the Air being <lb/>drawn out, the bubbles began to di&longs;cover <lb/>them&longs;elves at the bottom and &longs;ides of the <lb/>Gla&longs;s; and increa&longs;ing, as the Air was <lb/>more and more drawn away, they did <lb/>from time to time a&longs;cend copiou&longs;ly e­<lb/>nough to the top of the Water, and there <lb/>quickly break: but by rea&longs;on that the <lb/>widene&longs;s of the Gla&longs;s allow'd them free <lb/>pa&longs;&longs;age through the Water, they did not <lb/>appear as in the former Experiments to <lb/>make it &longs;well: The Water &longs;carce ever ri­<lb/>&longs;ing at all above the mark affixt to its up­<lb/>per &longs;urface when it was put in, and upon <lb/>the return permitted to the outward Air, <lb/>and con&longs;equently the &longs;hrinking in of the <lb/>remaining bubbles, the Water &longs;eem'd to <lb/>have lo&longs;t of its fir&longs;t extent, by the avo­<lb/>lation of the formerly inter&longs;per&longs;'d Air. </s></p><p type="main"> <s>Being willing likewi&longs;e to try whether <lb/>di&longs;tilled Water were by having been di­<lb/>vided into minute parts, and then re-uni­<lb/>ted, more or le&longs;s di&longs;po&longs;'d to expand it <lb/>&longs;elf then Water not di&longs;till'd: We took <lb/>out of our Laboratory &longs;ome careful­<lb/>ly di&longs;till'd Rain-water, and put about <lb/>two Ounces of it into a round Gla&longs;s <pb xlink:href="013/01/214.jpg" pagenum="184"/>bubble with a very &longs;mall Neck (not ex­<lb/>ceeding the &longs;ixth part of an Inch in Dia­<lb/>meter) which we fill'd half way to the <lb/>top, and then convey'd it into the Recei­<lb/>ver; the i&longs;&longs;ue was, That though we drew <lb/>out more then ordinary, yet there ap­<lb/>pear'd not the lea&longs;t intume&longs;cence of the <lb/>Water, nor any a&longs;cending bubbles. </s></p><p type="main"> <s>But &longs;u&longs;pecting that either the &longs;mall <lb/>quantity of the water or the Figure of the <lb/>Ve&longs;&longs;el might have an intere&longs;t in this odde <lb/><emph type="italics"/>Phænomenon,<emph.end type="italics"/> we took the lately mention'd <lb/>Philo&longs;ophical Egge, and another not <lb/>much differing from it; the former we <lb/>fill'd up with di&longs;till'd Rain-water to the <lb/>old mark, and into the latter we put a <lb/>long Cylinder or Rod of &longs;olid Gla&longs;s to <lb/>&longs;treighten the cavity of the Neck by al­<lb/>mo&longs;t filling it up; and then pouring &longs;ome <lb/>di&longs;tilled Water into that al&longs;o, till it <lb/>reach'd within &longs;ome Fingers breadth of <lb/>the top, the Eggs were let down into the <lb/>Receiver. </s> <s>In this Experiment the Air <lb/>was &longs;o far drawn forth before there ap­<lb/>pear'd any bubble in either of the Gla&longs;&longs;es, <lb/>that the di&longs;parity betwixt this and com­<lb/>mon water was manife&longs;t enough. </s> <s>But at <lb/>length, when the Air was almo&longs;t quite <lb/>pump'd out, the bubbles began to di&longs;-<pb xlink:href="013/01/215.jpg" pagenum="185"/>clo&longs;e them&longs;elves, and to increa&longs;e as the <lb/>pre&longs;&longs;ure of the Air in the Receiver de­<lb/>crea&longs;'d. </s> <s>But whereas in the fir&longs;t men­<lb/>tion'd Philo&longs;ophical Egge the bubbles <lb/>were very &longs;mall, and never able to &longs;well <lb/>the Water, that we took notice of, at all <lb/>above the mark: In the other, who&longs;e <lb/>Neck, as we lately &longs;aid, was &longs;traightned, <lb/>and their pa&longs;&longs;age ob&longs;tructed, great num­<lb/>bers of them, and bigger, fa&longs;tned them­<lb/>&longs;elves to the lower end of the Gla&longs;s ram­<lb/>mer (if we may &longs;o call it) and gather'd in <lb/>&longs;uch numbers between that and the &longs;ides <lb/>of the Neck, that the Water &longs;well'd a­<lb/>bout a Fingers breadth above the mark, <lb/>though upon the admitting of the exter­<lb/>nal Air it relap&longs;'d to the former mark, or <lb/>rather fell &longs;omewhat below it. </s> <s>And al­<lb/>though thereupon in the fir&longs;t nam'd Ve&longs;­<lb/>&longs;el all the bubbles pre&longs;ently di&longs;-appear'd, <lb/>yet in the other we ob&longs;erv'd, that divers <lb/>remained fa&longs;tned to the lower part of the <lb/>Gla&longs;s rammer, and continued there &longs;ome­<lb/>what to our wonder, for above an hour <lb/>after, but contracted in their Dimen­<lb/>&longs;ions. </s></p><p type="main"> <s>Moreover, having &longs;uffered the Gla&longs;&longs;es <lb/>to remain above twenty four hours in the <pb xlink:href="013/01/216.jpg" pagenum="186"/>Receiver, we afterwards repeated the Ex­<lb/>periment, to try what change the ex&longs;ucti­<lb/>on of the external Air would produce in <lb/>the Water, after the internal and latitant <lb/>Air had (as is above recited) in great mea­<lb/>&longs;ure got away in bubbles, and whether or <lb/>no the Water would by &longs;tanding re-admit <lb/>any new particles of Air in the room of <lb/>tho&longs;e that had for&longs;aken it. </s> <s>But though <lb/>we exhau&longs;ted the Receiver very diligent­<lb/>ly, yet we &longs;carce &longs;aw a bubble in either <lb/>of the Gla&longs;&longs;es; notwith&longs;tanding which, <lb/>we perceiv'd the Water to ri&longs;e about the <lb/>breadth of a Barly-corn, or more, in the <lb/>Neck of that Gla&longs;s wherein the &longs;olid Cy­<lb/>linder had been put; The Liquor in the <lb/>other Gla&longs;s not &longs;en&longs;ibly &longs;welling. </s></p><p type="main"> <s>And la&longs;tly, upon the letting in of the <lb/>Air, the Water in the &longs;traightned Neck <lb/>&longs;oon &longs;ub&longs;ided to the mark above which <lb/>it had &longs;wollen, which whether it ought <lb/>to be a&longs;crib'd to the &longs;ame &longs;mall expan&longs;ion <lb/>of the parts of the Water it &longs;elf, or to <lb/>the rarifaction of &longs;ome yet latitant Air <lb/>broken into &longs;uch &longs;mall particles, as to e­<lb/>&longs;cape our ob&longs;ervation, &longs;eems not ea&longs;ily <lb/>determinable, without &longs;uch further tryals, <lb/>as would perhaps prove tedious to be re­<lb/>cited as well as to be made; though I was <pb xlink:href="013/01/217.jpg" pagenum="187"/>content to &longs;et down tho&longs;e already men­<lb/>tion'd, that it might appear how requi­<lb/>&longs;ite it is in nice Experiments to con&longs;ider <lb/>variety of Circum&longs;tances. </s></p><p type="main"> <s>AFter having thus di&longs;cover'd what ope­<lb/><arrow.to.target n="marg31"/><lb/>ration the ex&longs;uction of the ambient <lb/>Air had upon Water, we thought good <lb/>to try al&longs;o what changes would happen in <lb/>other Liquors upon the like taking off the <lb/>pre&longs;&longs;ure of the external Air. </s> <s>We took <lb/>then a Gla&longs;s Egge, &longs;omewhat bigger then <lb/>a Turkey Egge, which had a long Neck <lb/>or Stem of about a 1/3 part of an Inch in <lb/>Diameter; and filling it up with Sallet <lb/>Oyl until it reach'd above half way to the <lb/>top of the Neck, we inclo&longs;'d it in the Re­<lb/>ceiver together with common Water in <lb/>a re&longs;embling Ve&longs;&longs;el, that we might the <lb/>better compare together the operation of <lb/>the ex&longs;uction of the Air upon tho&longs;e two <lb/>Liquors. </s> <s>The Pump being &longs;et a work there <lb/>began to appear bubbles in the Oyl much <lb/>&longs;ooner then in the Water, and afterwards <lb/>they al&longs;o a&longs;cended much more copiou&longs;ly <lb/>in the former Liquor then the latter: Nay, <lb/>and when by having quite tired the Pum­<lb/>per, and almo&longs;t our own patience, we <pb xlink:href="013/01/218.jpg" pagenum="188"/>gave over, the bubbles ri&longs;e almo&longs;t (if <lb/>not altogether) in as great numbers <lb/>as ever, in&longs;omuch as none of the various <lb/>Liquors we tryed either before or &longs;ince, <lb/>&longs;eem'd to abound more with Aerial Parti­<lb/>cles then did this Oyl. </s> <s>In which it was <lb/>further remarkable, that between the time <lb/>it was &longs;et into the Receiver, and that at <lb/>which we could get ready to Pump, it &longs;ub­<lb/>&longs;ided notably (by ghe&longs;s about half an <lb/>Inch) below the mark it reach'd before it <lb/>was put in. </s></p><p type="margin"> <s><margin.target id="marg31"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 24.</s></p><p type="main"> <s>After this expre&longs;&longs;'d Oyl, we made tryal <lb/>of a di&longs;till'd one, and for that purpo&longs;e <lb/>made choice of the common Oyl or Spi­<lb/>rit (for in the Shops where it is &longs;old, the <lb/>&longs;ame Liquor is promi&longs;cuou&longs;ly call'd by ei­<lb/>ther name) of Turpentine; becau&longs;e 'twas <lb/>onely of that Chymical Oyl, we had a <lb/>&longs;ufficient quantity: which, being put in­<lb/>to a &longs;mall Gla&longs;s bubble with a &longs;lender <lb/>Neck, &longs;o as to fill it to about two Inches <lb/>from the top, did, upon the evacuating <lb/>of the Receiver, pre&longs;ent us with great <lb/>&longs;tore of bubbles; mo&longs;t of which ri&longs;ing <lb/>from the bottom, expanded them&longs;elves <lb/>exceedingly in their a&longs;cent, and made the <lb/>Liquor in the Neck to &longs;well &longs;o much by <lb/>degrees, that at length it divers times ran <pb xlink:href="013/01/219.jpg" pagenum="189"/>over at the top: by which means, we <lb/>were hindred from being able to di&longs;cern <lb/>upon the letting in of the Air, how much <lb/>the &longs;ub&longs;idence of the Oyl below the fir&longs;t <lb/>mark was due to the rece&longs;s of the bub­<lb/>bles. </s></p><p type="main"> <s>Having likewi&longs;e a minde to try whe­<lb/>ther as &longs;trong a &longs;olution of Salt of Tartar <lb/>in fair Water as could be made (we ha­<lb/>ving then no Oyl of Tartar <emph type="italics"/>per deliqui­<lb/>um<emph.end type="italics"/> at hand) though it be accounted, <lb/>Quick-&longs;ilver excepted, the heavie&longs;t of <lb/>Liquors would afford us any bubbles; we <lb/>put in a Gla&longs;s Egge full of it at the &longs;ame <lb/>time, with other Liquors, and found that <lb/>they did long yield &longs;tore of bubbles be­<lb/>fore any di&longs;covered them&longs;elves in the <lb/>Liquor of Tartar; and having pur&longs;ued <lb/>the Experiment, it appear'd, That of all <lb/>the Liquors we made tryal of, this afford­<lb/>ed the fewe&longs;t and the &longs;malle&longs;t Bubbles. </s></p><p type="main"> <s>Spirit of Vinager being try'd after the <lb/>&longs;ame manner, exhibited a moderate num­<lb/>ber of bubbles, but &longs;carce any thing el&longs;e <lb/>worth the mentioning. </s></p><p type="main"> <s>Nor could we in red Wine, try'd in a <lb/>Gla&longs;s Egge, take notice of any thing ve­<lb/>ry ob&longs;ervable. </s> <s>For though upon the ex­<lb/>&longs;uction of the Air the bubbles a&longs;cended <pb xlink:href="013/01/220.jpg" pagenum="190"/>in this Liquor, as it were in &longs;holes, <lb/>and &longs;hifted places among them&longs;elves in <lb/>their a&longs;cent; yet the Intume&longs;cence of the <lb/>whole bulk of the Liquor was &longs;carce at all <lb/>&longs;en&longs;ible, the bubbles mo&longs;t commonly <lb/>breaking very &longs;oon after their arrival at <lb/>the top, where during their &longs;tay, they <lb/>compo&longs;'d a kinde of &longs;hallow froth, which <lb/>alone appear'd higher in the Neck of the <lb/>Gla&longs;s, then was the Wine when it was <lb/>fir&longs;t let down. </s> <s>Neither yet did Milk, con­<lb/>vey'd into our Pneumatical Ve&longs;&longs;el, pre­<lb/>&longs;ent us with any thing memorable, &longs;ave <lb/>that (as it &longs;eem'd by rea&longs;on of &longs;ome un­<lb/>ctuou&longs;ne&longs;s of the Liquor) the bubbles <lb/>not ea&longs;ily breaking at the top, and thru&longs;t­<lb/>ing up one another made the intume&longs;cence <lb/>appear much greater then that of common <lb/>Water. </s></p><p type="main"> <s>We likewi&longs;e convey'd Hens Eggs into <lb/>the Receiver, but, after the ex&longs;uction of <lb/>the Air, took them out whole again. </s> <s>That <lb/>which invited us to put them in, was, That <lb/>(as perhaps we mention in other Papers) <lb/>we had among other Experiments of <lb/>cold, made Eggs bur&longs;t, by freezing them <lb/>within doors with Snow and Salt: The <lb/>Ice, into which the aqueous parts of the <lb/>Egge were turned by the cold, &longs;o di&longs;tend-<pb xlink:href="013/01/221.jpg" pagenum="191"/>ing (probably by rea&longs;on of the numerous <lb/>bubbles wont to be ob&longs;ervable in Ice) the <lb/>outward parts of the Egge, that it u&longs;ually <lb/>crack'd the &longs;hell, though the inner Mem­<lb/>brane that involv'd the &longs;everal Liquors <lb/>of the Egge, becau&longs;e it would &longs;tretch <lb/>and yield, remain d unbroken, And here­<lb/>upon we imagin'd that in our Engine it <lb/>might appear whether or no there were <lb/>any con&longs;iderable Spring, either in any of <lb/>the Liquors, or in any other more &longs;piri­<lb/>tuous &longs;ub&longs;tance included in the Egge. </s></p><p type="main"> <s>We took al&longs;o &longs;ome Spirit of Urine, <lb/>carele&longs;ly enough deflegmed, and put it in­<lb/>to the &longs;ame Gla&longs;s (fir&longs;t carefully &longs;cowr'd <lb/>and clean&longs;'d) wherein we had put the Oyl­<lb/>olive above mention'd: We took al&longs;o an­<lb/>other Gla&longs;s, differing from a Gla&longs;s Egge, <lb/>onely in that its bottom was &longs;lat, and fill'd <lb/>it up to about 2/3 of the Neck (which was <lb/>wider then that of the Egge) with rectifi­<lb/>ed Spirit of Wine. </s></p><p type="main"> <s>We took al&longs;o another Gla&longs;s Egge, and <lb/>having fill'd it with common Water till it <lb/>reach'd to the middle of the Neck, we <lb/>pour'd to it of the &longs;ame Spirit of Wine, <lb/>till it reach'd about an Inch higher. </s></p><p type="main"> <s>The&longs;e three Gla&longs;&longs;es having marks &longs;et <lb/>on them, over again&longs;t the edges of the <pb xlink:href="013/01/222.jpg" pagenum="192"/>contain'd Liquors were put into the Re­<lb/>ceiver, and that beginning to be evacua­<lb/>ted, the bubbles in all the three Liquors <lb/>began to appear. </s> <s>The mixture of the <lb/>Spirit of Wine and Water di&longs;clo&longs;'d a <lb/>great &longs;tore of bubbles, e&longs;pecially towards <lb/>the top; but &longs;carce afforded us any thing <lb/>worth remem bring. </s> <s>The Spirit of Urine <lb/>appear'd to &longs;well near an Inch and an half <lb/>above the mark; and be&longs;ides that, &longs;ent <lb/>forth &longs;tore of bubbles, which made a <lb/>kinde of froth at the upper part of it. </s> <s>And <lb/>above that &longs;pume there appear'd eight or <lb/>ten great bubbles one above another, in a <lb/>very decent order, each of them con&longs;titu­<lb/>ting, as it were, a Cylinder of about half <lb/>an Inch high, and as broad as the internal <lb/>cavity of the Neck: So that all the upper <lb/>part of the Neck (for the&longs;e bubbles reach'd <lb/>to the top) &longs;eem'd to be divided into al­<lb/>mo&longs;t equal parts, by certain Diaphrag­<lb/>mes, con&longs;i&longs;ting of the coats of the bub­<lb/>bles, who&longs;e edges appear'd like &longs;o many <lb/>Rings &longs;u&longs;pended one above another. </s></p><p type="main"> <s>In the Spirit of Wine there did ari&longs;e a <lb/>great multitude of bubbles, even till <lb/>wearine&longs;s did make us give over the Ex­<lb/>periment. </s> <s>And in the&longs;e bubbles two or <lb/>three things were remarkable; as fir&longs;t, <pb xlink:href="013/01/223.jpg" pagenum="193"/>That they a&longs;cended with a very notable <lb/>celerity: Next, That being arriv'd at the <lb/>top, they made no &longs;tay there, and yet, <lb/>notwith&longs;tanding the great thinne&longs;s and <lb/>&longs;pitituou&longs;ne&longs;s of the Liquor, did, before <lb/>they broke, lift up the upper &longs;urface of <lb/>it, and for a moment or two form thereof <lb/>a thin film or skin which appear'd protu­<lb/>berant above the re&longs;t of the &longs;uperficies <lb/>like a &longs;mall Hemi&longs;phere. </s> <s>Thirdly, That <lb/>they a&longs;cended &longs;traight up, whereas tho&longs;e <lb/>produc'd at the lower part of the Ve&longs;&longs;el, <lb/>containing the mixture of the Water and <lb/>Spirit of Wine, a&longs;cended with a waver­<lb/>ing or wrigling motion, whereby they <lb/>de&longs;crib'd an indented Line. </s> <s>La&longs;tly, It <lb/>was ob&longs;ervable in the Spirit of Wine (and <lb/>we took notice of the like in the Oyl of <lb/>Turpentine lately mention'd) that not <lb/>onely the bubbles &longs;eem'd to ri&longs;e from cer­<lb/>tain determinate places at the bottom of <lb/>the Gla&longs;s, but that in their a&longs;cen&longs;ion they <lb/>kept an almo&longs;t equal di&longs;tance from each <lb/>other, and follow'd one another in a cer­<lb/>tain order, whereby they &longs;eem'd part of <lb/>&longs;mall Bracelets, con&longs;i&longs;ting of equally lit­<lb/>tle incontiguous Beads: the lower end of <lb/>each Bracelet, being as it were, fa&longs;ten'd to <lb/>a certain point at the bottom of the Gla&longs;s. </s></p><pb xlink:href="013/01/224.jpg" pagenum="194"/><p type="main"> <s>The Air being &longs;paringly let into the <lb/>Receiver, the great bubbles formerly <lb/>mention'd as incumbent upon one ano­<lb/>ther, in that Gla&longs;s that contain'd the Spi­<lb/>rit of Urine, were by orderly degrees <lb/>le&longs;&longs;en'd, till at length they wholly &longs;ub&longs;i­<lb/>ded, notwith&longs;tanding the rece&longs;s of &longs;o ma­<lb/>ny bubbles as broke on the top of the <lb/>Spirit of Urine, during all the time of the <lb/>Experiment; yet it &longs;carcely appear'd at all <lb/>to be &longs;unk below the mark: Nor did the <lb/>mixture of Spirit of Wine and Water <lb/>con&longs;iderably &longs;ub&longs;ide. </s> <s>But that is no­<lb/>thing to what we ob&longs;erv'd in the Spirit <lb/>of Wine, for not onely it con&longs;picuou&longs;ly <lb/>expanded it &longs;elf in the Neck of the <lb/>Ve&longs;&longs;el that contain'd it, notwith&longs;tand­<lb/>ing the largene&longs;s of it; and that the <lb/>bubbles were about to break at the <lb/>top of it almo&longs;t a&longs;&longs;oon as they arriv'd <lb/>there: but upon the re-admi&longs;&longs;ion of <lb/>the external Air, the Spirit of Wine <lb/>retain'd its newly acquired expan&longs;ion. <lb/></s> <s>And though we let it alone for near <lb/>an hour together, in expectation that it <lb/>might &longs;ub&longs;ide; yet when we took it <lb/>out, we found it &longs;till &longs;well'd between a <lb/>quarter and half an Inch above the <lb/>mark; and although it was not ea&longs;ily <pb xlink:href="013/01/225.jpg" pagenum="195"/>imaginable how this <emph type="italics"/>Phænomenon<emph.end type="italics"/> could <lb/>proceed from any mi&longs;take in trying <lb/>the Experiment, yet the &longs;trangene&longs;&longs;e <lb/>of it invited me to repeat it with fre&longs;h <lb/>Spirit of Wine; which, &longs;welling in the <lb/>Neck as formerly, I left all Night in <lb/>the Receiver, allowing free acce&longs;s to the <lb/>external Air at the Stop-cock, and the <lb/>next day found it &longs;till expanded as be­<lb/>fore, &longs;ave that it &longs;eem'd a little lower: <lb/>which decrement perhaps proceeded from <lb/>the avolation of &longs;ome of the fugitive <lb/>parts of &longs;o volatile a Liquor. </s> <s>And for <lb/>better &longs;atisfaction having taken out the <lb/>Gla&longs;s, and con&longs;ider'd it in the open Air, <lb/>and at a Window, I could not finde that <lb/>there was any remaining Bubbles that <lb/>could occa&longs;ion the per&longs;evering and ad­<lb/>mir'd expan&longs;ion. </s></p><p type="main"> <s>BEing de&longs;irous to di&longs;cover what diffe­<lb/><arrow.to.target n="marg32"/><lb/>rence there might be as to gravity and <lb/>levity, between Air expanded under Wa­<lb/>ter, and it &longs;elfe before &longs;uch expan&longs;ion; we <lb/>took two very &longs;mall Viols, &longs;uch as Chy­<lb/>mical E&longs;&longs;ences (as they call them) are wont <lb/>to be kept in, and of the &longs;ize and &longs;hape ex­<lb/>pre&longs;&longs;ed by the 8<emph type="sup"/>th<emph.end type="sup"/> Figure: into one of the&longs;e <pb xlink:href="013/01/226.jpg" pagenum="196"/>we put &longs;o much of a certain ponderous <lb/>Mercurial mixture (hapning to be then at <lb/>hand) that the mouth being &longs;topt with a <lb/>little &longs;oft Wax, the Gla&longs;s would ju&longs;t &longs;ink <lb/>in Water and no more; this we let fall to <lb/>the bottom of a wide-mouth'd Cry&longs;tal <lb/>Jar, fill'd with about half a pint of com­<lb/>mon Water, and into the &longs;ame Ve&longs;&longs;el we <lb/>&longs;unk the other E&longs;&longs;ence Gla&longs;s un&longs;topp'd, <lb/>with as much Water in it as was more <lb/>then &longs;ufficient to make it &longs;ub&longs;ide. </s> <s>Both <lb/>the&longs;e &longs;unk with their mouthes downward, <lb/>the former being about three quarters full <lb/>of Air, the latter containing in it a bub­<lb/>ble of Air that was ghe&longs;&longs;'d to be of the <lb/>bigne&longs;s of half a Pea: This done, the <lb/>wide-mouth'd Gla&longs;s was let down into <lb/>the Receiver, and the way of imploy­<lb/>ing the Engine was carefully made u&longs;e <lb/>of. </s></p><p type="margin"> <s><margin.target id="marg32"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 25.</s></p><p type="main"> <s>The &longs;ucce&longs;s was, That having drawn <lb/>out a pretty quantity of Air, the bubbles <lb/>began to di&longs;clo&longs;e them&longs;elves in the Wa­<lb/>ter, as in the former Experiments; and <lb/>though for a good while after the bubbles <lb/>a&longs;cended in &longs;warms from the lower parts <lb/>of the Water, and ha&longs;tily broke at the <lb/>top; yet we pro&longs;ecuted the Experiment <lb/>&longs;o long without &longs;eeing any effect wrought <pb xlink:href="013/01/227.jpg" pagenum="197"/>upon the E&longs;&longs;ence: Bottles, that we began <lb/>to di&longs;pair of &longs;eeing either of them ri&longs;e, but <lb/>continuing to ply the Pump, that little <lb/>Gla&longs;s, who&longs;e mouth was open'd, came to <lb/>the top of the Water, being, as it were, <lb/>boy'd up thither by a great number of <lb/>bubbles that had fa&longs;tned them&longs;elves to <lb/>the &longs;ides of it; &longs;wimming thus with the <lb/>mouth downward, we could ea&longs;ily per­<lb/>ceive that the internal Air above men­<lb/>tion'd had much delated it &longs;elf, and there­<lb/>by &longs;eem'd to have contributed to the e­<lb/>merging of the Gla&longs;s, which remain'd <lb/>floating, notwith&longs;tanding the breaking <lb/>and vani&longs;hing of mo&longs;t of the contiguous <lb/>bubbles: being hereby incouraged to per­<lb/>&longs;i&longs;t in pumping, we ob&longs;erved with &longs;ome <lb/>plea&longs;ure, that at each time we turn'd the <lb/>Key, the Air in the little Gla&longs;s did mani­<lb/>fe&longs;tly expand it &longs;elf and thru&longs;t out the wa­<lb/>ter, generally retaining a very protuberant <lb/>&longs;urface where it was contiguous to the re­<lb/>maining Water. </s> <s>And when after divers <lb/>ex&longs;uctions of the Air in the Receiver, <lb/>that in the little Viol &longs;o dilated it &longs;elf as <lb/>to expel almo&longs;t all the Water, it turn'd <lb/>up its mouth towards the &longs;urface of the <lb/>Water in the Jar, and there deliver'd a <lb/>large bubble, and then relap&longs;ed into its <pb xlink:href="013/01/228.jpg" pagenum="198"/>formér floating po&longs;ture: And this Expe­<lb/>riment taught us, among other things, <lb/>that it was a work of more time and la­<lb/>bor then we imagin'd, to exhau&longs;t our En­<lb/>gine as much as it may be exhau&longs;ted: for <lb/>although before the emerging of the &longs;mall <lb/>Viol, we did (as has been touch'd alrea­<lb/>dy) think we had very con&longs;iderably em­<lb/>ptyed the Receiver, becau&longs;e there &longs;eem'd <lb/>to come out but very little or almo&longs;t <lb/>no &longs;en&longs;ible Air at each ex&longs;uction into <lb/>and out of the Cylinder; yet after­<lb/>wards, at each drawing down the Suc­<lb/>ker, the Air included in the Viol did <lb/>manife&longs;tly dilate it &longs;elf, &longs;o long, that <lb/>it did no le&longs;s then nine times turn its <lb/>mouth upwards, and di&longs;charge a bub­<lb/>ble by conjecture about the bigne&longs;s of <lb/>a Pea, after the manner newly recited. <lb/></s> <s>But as for that Violl which had the <lb/>weight in it, it ro&longs;e not at all. </s> <s>So <lb/>that being not able by quick pumping <lb/>to gain another bubble from the Air <lb/>in the &longs;wimming Gla&longs;s, which proceed­<lb/>ed from &longs;ome &longs;mall leak in the Ve&longs;&longs;el, <lb/>though it held in this Experiment more <lb/>&longs;tanch then was u&longs;ual, we thought fit <lb/>to let in lea&longs;urely the Air from with­<lb/>out, upon who&longs;e admi&longs;&longs;ion that with-<pb xlink:href="013/01/229.jpg" pagenum="199"/>in the Viol &longs;hrinking into a very nar­<lb/>row compa&longs;s, the Gla&longs;s did, as we expe­<lb/>cted, fall down to the bottom of the <lb/>Jar. </s></p><p type="main"> <s>But being de&longs;irous before we proceed­<lb/>ed to any new. </s> <s>Experiment, to try once <lb/>more whether the little Gla&longs;s that had <lb/>the weight in it might not al&longs;o be rai&longs;'d. <lb/></s> <s>After we had &longs;uffer'd the Engine to re­<lb/>main clo&longs;'d as it was, for five or &longs;ix <lb/>hours, the Pump was again ply'd with <lb/>&longs;o much ob&longs;tinacy, that not onely a­<lb/>bout the upper part of the Jar there ap­<lb/>pear'd a good number of bubbles (but <lb/>very much &longs;maller then tho&longs;e we &longs;aw <lb/>the fir&longs;t time) but afterwards there <lb/>came from the bottom of the Jar, bub­<lb/>bles about the bigne&longs;s of &longs;mal Peas: which <lb/>the Pump being &longs;till kept going, fol­<lb/>low'd one another, to the number of forty, <lb/>coming from the &longs;topp'd Violl; who&longs;e <lb/>mouth, it &longs;eems, had not been &longs;hut &longs;o <lb/>&longs;trongly and clo&longs;ely, but that the included <lb/>Air, dilating it &longs;elf by its own &longs;pring, made <lb/>it&longs;elf &longs;ome little pa&longs;&longs;age betwixt the Wall <lb/>and the Gla&longs;s, and got away in the&longs;e bub­<lb/>bles; after which, the un&longs;topp'd Gla&longs;s be­<lb/>gan to float again, the Air &longs;hut up in it <pb xlink:href="013/01/230.jpg" pagenum="200"/>being manife&longs;tly &longs;o dilated as to expel a <lb/>good part of the Water, but not &longs;o much <lb/>as to break quite thorow. </s> <s>And at length, <lb/>when our expectation of it was almo&longs;t ti­<lb/>red out, the heavier of the two Viols be­<lb/>gan to come aloft, and immediately to <lb/>&longs;ub&longs;ide again, which appear'd to be oc­<lb/>ca&longs;ion'd by the Air within it, who&longs;e bulk <lb/>and &longs;pring being weaken'd by the rece&longs;s <lb/>of the forty bubbles before-mention'd, it <lb/>was no longer able, as formerly, to break <lb/>forcibly through the incumbent Water; <lb/>but forming a bubble at the mouth of the <lb/>Gla&longs;s, boyed it up towards the top, and <lb/>there getting away, left it to &longs;ink again <lb/>till the pre&longs;&longs;ure of the Air in the Recei­<lb/>ver being further taken off, the Air in the <lb/>Viol was permitted to expand it &longs;elf fur­<lb/>ther, and to create another bubble, by <lb/>which it was again for a while carried up. <lb/></s> <s>And it was remarkable, that though after <lb/>having emptyed the Receiver as far as <lb/>well we could, we cea&longs;'d from pumping; <lb/>yet the Ve&longs;&longs;el continuing more &longs;tanch <lb/>then it was wont, this a&longs;cent and fall of <lb/>the Viol was repeated to the ninth time; <lb/>the included Air, by rea&longs;on of the &longs;mal­<lb/>ne&longs;s of the vent at which it mu&longs;t pa&longs;s out, <lb/>being not able to get away otherwi&longs;e then <pb xlink:href="013/01/231.jpg" pagenum="201"/>little by little; and con&longs;equently, in divers <lb/>&longs;uch parcels as were able to con&longs;titute <lb/>bubbles, each of them big enough to <lb/>rai&longs;e the Viol and keep it aloft until the <lb/>avolation of that bubble. </s> <s>Whereby it <lb/>may appear, that the grand rule in <emph type="italics"/>Hy­<lb/>dro&longs;taticks,<emph.end type="italics"/> That a Body will &longs;wim in the <lb/>Water, in ca&longs;e it be lighter then as much <lb/>of that Water that equals it in bulk, will <lb/>hold likewi&longs;e when the pre&longs;&longs;ure of the At­<lb/>mo&longs;phere is in very great mea&longs;ure, if not <lb/>when it is totally taken off from the Li­<lb/>quor and the Body: though it were worth <lb/>inquiring what it is that &longs;o plentifully <lb/>concurs to fill the bubbles made in our <lb/>Experiment by the &longs;o much expanded <lb/>Air, for to &longs;ay with the old Peripatetick <lb/>Schools, That the Air, in Rarefaction, <lb/>may acquire a new extent, without the <lb/>admi&longs;&longs;ion of any new &longs;ub&longs;tance, would <lb/>be an account of the <emph type="italics"/>Phænomenon<emph.end type="italics"/> very <lb/>much out of date, and which, I &longs;uppo&longs;e, <lb/>our Modern Naturali&longs;ts would neither <lb/>give, nor acquie&longs;s in. </s></p><p type="main"> <s>I know not whether it may be requi&longs;ite <lb/>to adde, that in this Experiment, as in <lb/>the former, the outward Air being let in <lb/>did &longs;oon precipitate the floating Viol. </s> <s>But <lb/>I think it will not be ami&longs;s to note, that <pb xlink:href="013/01/232.jpg" pagenum="202"/>(congruou&longs;ly to what hath been above <lb/>recorded of the va&longs;t expan&longs;ion of the Air) <lb/>the Water which in the heavier Viol &longs;uc­<lb/>ceeded in the room of tho&longs;e forty odde, if <lb/>not fifty great bubbles of Air, which at <lb/>&longs;everal times got out of it, amounted but <lb/>to a very incon&longs;iderable bigne&longs;s. </s></p><p type="main"> <s>IT having been ob&longs;erv'd by tho&longs;e that <lb/><arrow.to.target n="marg33"/><lb/>have con&longs;ider'd what belongs to <emph type="italics"/>Pendu­<lb/>lums<emph.end type="italics"/> (a Speculation that may, in my <lb/>poor judgement, be highly u&longs;eful to the <lb/>Naturali&longs;ts) that their Vibrations are <lb/>more &longs;lowly made, and that their moti­<lb/>on la&longs;ts le&longs;s in a thicker, then in a thinner <lb/>Medium: We thought it not ami&longs;s to <lb/>try if a <emph type="italics"/>Pendulum<emph.end type="italics"/> would &longs;wing fa&longs;ter, or <lb/>continue &longs;winging longer in our Receiver, <lb/>in ca&longs;e of the ex&longs;uction of the Air, then <lb/>otherwi&longs;e. </s> <s>Wherefore we took a couple <lb/>of round and poli&longs;h'd <emph type="italics"/>Pendulums<emph.end type="italics"/> of Iron <lb/>or Steel, of equal bigne&longs;s, as near as we <lb/>could get the Artificer to make them, and <lb/>weighing each of them twenty Dragmes, <lb/>wanting as many Grains. </s> <s>One of the&longs;e <lb/>we &longs;u&longs;pended in the cavity of the Recei­<lb/>ver by a very &longs;lender &longs;ilken &longs;tring, of a­<lb/>bout &longs;even Inches and a half in length <pb xlink:href="013/01/233.jpg" pagenum="203"/>from the cover of the Receiver to which <lb/>it was fa&longs;ten'd. </s> <s>Then (by inclining the <lb/>Engine) we made the <emph type="italics"/>Pendulum<emph.end type="italics"/> &longs;wing too <lb/>and fro in it, and de&longs;crib'd as long Arches <lb/>as in the capacity of &longs;o brittle a Ve&longs;&longs;el we <lb/>thought &longs;afe and convenient. </s> <s>And one of <lb/>the A&longs;&longs;i&longs;tants telling the recur&longs;ions of the <lb/>other <emph type="italics"/>Pendulum<emph.end type="italics"/> hanging in the free Air, <lb/>by a &longs;tring of about the &longs;ame length, we <lb/>&longs;horten'd and lengthen'd this other <emph type="italics"/>Pen­<lb/>dulum,<emph.end type="italics"/> till it appear'd to keep the &longs;ame <lb/>pace in its Vibrations, with that &longs;hut up in <lb/>the Receiver. </s> <s>Then having carefully <lb/>drawn away the Air, we did again &longs;et the <lb/><emph type="italics"/>Pendulum<emph.end type="italics"/> in the Receiver a vibrating; <lb/>and giving the other <emph type="italics"/>Pendulum<emph.end type="italics"/> &longs;uch a mo­<lb/>tion as made it de&longs;cribe an Arch, accord­<lb/>ing to ones ghe&longs;s, equal to that of the in­<lb/>cluded <emph type="italics"/>Pendulum;<emph.end type="italics"/> we reckon'd, one of <lb/>us, the Recur&longs;ions of that <emph type="italics"/>Pendulum<emph.end type="italics"/> which <lb/>was &longs;winging within the Receiver; and <lb/>another of us that which was moving in <lb/>(that which one would think a much more <lb/>re&longs;i&longs;ting <emph type="italics"/>medinm<emph.end type="italics"/>) the Air. </s> <s>But once, one <lb/>of us reckon'd near two and twenty Re­<lb/>cur&longs;ions of the included <emph type="italics"/>Pendulum,<emph.end type="italics"/> whil&longs;t <lb/>the other reckon'd but twenty of the <emph type="italics"/>Pen­<lb/>dulum<emph.end type="italics"/> that vibrated without. </s> <s>And an­<lb/>other time al&longs;o, the former of the&longs;e <emph type="italics"/>Pen-<emph.end type="italics"/><pb xlink:href="013/01/234.jpg" pagenum="204"/><emph type="italics"/>dula<emph.end type="italics"/> was reckon'd to have made one and <lb/>twenty Recur&longs;ions, wherein the other <lb/>made but twenty: Yet this Experiment <lb/>&longs;eem'd to teach us little, &longs;ave that the dif­<lb/>ference betwixt the motion of &longs;uch a <emph type="italics"/>Pen­<lb/>dulum<emph.end type="italics"/> in the common Air, and in one ex­<lb/>ceedingly rarified, is &longs;carce &longs;en&longs;ible in <lb/>Ve&longs;&longs;els no bigger then our Receiver; e­<lb/>&longs;pecially &longs;ince though during this Expe­<lb/>riment it held very well, yet we could <lb/>not &longs;uppo&longs;e it to be altogether devoid of <lb/>Air. </s> <s>We ob&longs;erv'd al&longs;o, that when the <lb/>Receiver was full of Air, the included <lb/><emph type="italics"/>Pendulum<emph.end type="italics"/> continu'd its Recur&longs;ions about <lb/>fifteen minutes (or a quarter of an hour) <lb/>before it left off &longs;winging; and that after <lb/>the ex&longs;uction of the Air, the Vibration <lb/>of the &longs;ame <emph type="italics"/>Pendulum<emph.end type="italics"/> (being fre&longs;h put in­<lb/>to motion) appear'd not (by a minutes <lb/>Watch) to la&longs;t &longs;en&longs;ibly longer. </s> <s>So that <lb/>the event of this Experiment being other <lb/>then we expected, &longs;carce afforded us any <lb/>other &longs;atisfaction, then that of our not <lb/>having omitted to try it. </s> <s>And whether <lb/>in ca&longs;e the tryal be made with a <emph type="italics"/>Pendulum<emph.end type="italics"/><lb/>much le&longs;s di&longs;proportionate to the Air then <lb/>Steel is, the event will much better an­<lb/>&longs;wer expectation, experience may be con­<lb/>&longs;ulted. </s></p><pb xlink:href="013/01/235.jpg" pagenum="205"/><p type="margin"> <s><margin.target id="marg33"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 26.</s></p><p type="main"> <s>THat the Air is the medium whereby <lb/>&longs;ounds are convey'd to the Ear, has <lb/><arrow.to.target n="marg34"/><lb/>been for many Ages, and is yet the com­<lb/>mon Doctrine of the Schools. </s> <s>But this <lb/>Received Opinion has been of late op­<lb/>po&longs;'d by &longs;ome Philo&longs;ophers upon the ac­<lb/>count of an Experiment made by the <lb/>Indu&longs;trious <emph type="italics"/>Kircher,<emph.end type="italics"/> and other Learned <lb/>Men, who have (as they a&longs;&longs;ure us) ob­<lb/>&longs;erv'd, That if a Bell, with a Steel Clap­<lb/>per, be &longs;o fa&longs;ten'd to the in&longs;ide of a Tube, <lb/>that upon the making the Experiment <emph type="italics"/>De <lb/>Vacuo<emph.end type="italics"/> with that Tube, the Bell remain'd <lb/>&longs;u&longs;pended in the de&longs;erted &longs;pace at the up­<lb/>per end of the Tube: And if al&longs;o a vi­<lb/>gorous Load-&longs;tone be apply'd on the out­<lb/>&longs;ide of the Tube to the Bell, it will at­<lb/>tract the Clapper, which upon the Remo­<lb/>val of the Load-&longs;tone falling back, will <lb/>&longs;trike again&longs;t the oppo&longs;ite &longs;ide of the <lb/>Bell, and thereby produce a very audible <lb/>&longs;ound, whence divers have concluded, <lb/>That 'tis not the Air, but &longs;ome more &longs;ub­<lb/>tle Body that is the medium of &longs;ounds. <lb/></s> <s>But becau&longs;e we conceiv'd that, to invali­<lb/>date &longs;uch a con&longs;equence from this ingeni­<lb/>ous Experiment (though the mo&longs;t lucife-<pb xlink:href="013/01/236.jpg" pagenum="206"/>rous, that could well be made without <lb/>&longs;ome &longs;uch Engine as ours) &longs;ome things <lb/>might be &longs;peciou&longs;ly enough alleadg'd; we <lb/>thought fit to make a tryal or two, in or­<lb/>der to the Di&longs;covery of what the Air does <lb/>in conveying of &longs;ounds, re&longs;erving divers <lb/>other Experiments tryable in our Engine <lb/>concerning &longs;ounds, till we can obtain more <lb/>lea&longs;ure to pro&longs;ecute them. </s> <s>Conceiving it <lb/>then the be&longs;t way to make our tryal with <lb/>&longs;uch a noi&longs;e as might not be loud enough <lb/>to make it difficult to di&longs;cern &longs;lighter va­<lb/>riations in it, but rather might be, both <lb/>la&longs;ting, that we might take notice by what <lb/>degrees it decrea&longs;'d; and &longs;o &longs;mall, that <lb/>it could not grow much weaker with­<lb/>out becoming imperceptible. </s> <s>We took <lb/>a Watch, who&longs;e Ca&longs;e we open'd, that <lb/>the contain'd Air might have free egre&longs;s <lb/>into that of the Receiver. </s> <s>And this Watch <lb/>was &longs;u&longs;pended in the cavity of the Ve&longs;&longs;el <lb/>onely by a Pack-thred, as the unlikelie&longs;t <lb/>thing to convey a &longs;ound to the top of the <lb/>Receiver: And then clo&longs;ing up the Ve&longs;­<lb/>&longs;el with melted Plai&longs;ter, we li&longs;ten'd near <lb/>the &longs;ides of it, and plainly enough heard <lb/>the noi&longs;e made by the ballance. </s> <s>Tho&longs;e al­<lb/>&longs;o of us, that watch'd for that Circum­<lb/>&longs;tance, ob&longs;erv'd, that the noi&longs;e &longs;eem'd to <pb xlink:href="013/01/237.jpg" pagenum="207"/>come directly in a &longs;traight Line from the <lb/>Watch unto the Ear. </s> <s>And it was ob&longs;erva­<lb/>ble to this purpo&longs;e, that we found a mani­<lb/>fe&longs;t di&longs;parity of noi&longs;e, by holding our Ears <lb/>near the &longs;ides of the Receiver, and near the <lb/>Cover of it: which difference &longs;eem'd to <lb/>proceed from that of the Texture of the <lb/>Gla&longs;s, from the &longs;tructure of the cover (and <lb/>of the Cement) through which the &longs;ound <lb/>was propagated from the Watch to the <lb/>Ear. </s> <s>But let us pro&longs;ecute our Experiment. <lb/></s> <s>The Pump after this being imployd, it <lb/>&longs;eemd that from time to time the &longs;ound <lb/>grew fainter and fainter; &longs;o that when the <lb/>Rec iver was empty'd as much as it u&longs;'d <lb/>to be for the foregoing Experiments, nei­<lb/>ther we, nor &longs;ome &longs;trangers that chanc'd <lb/>to be then in the room, could, by applying <lb/>our Ears to the very &longs;ides, hear any noi&longs;e <lb/>from within; though we could ea&longs;ily per­<lb/>ceive that by the moving of the hand <lb/>which mark'd the &longs;econd minutes, and by <lb/>that of the ballance, that the Watch nei­<lb/>ther &longs;tood &longs;til, nor remarkably varied from <lb/>its wonted motion. </s> <s>And to &longs;atisfie our <lb/>&longs;elvs further that it was indeed the ab&longs;ence <lb/>of the Air about the Watch that hinder'd <lb/>us from hearing it, we let in the external <lb/>Air at the Stop-cock, and then though we <pb xlink:href="013/01/238.jpg" pagenum="208"/>turn'd the Key and &longs;topt the Valve, yet we <lb/>could plainly hear the noi&longs;e made by the <lb/>ballance, though we held our Ears &longs;ome­<lb/>times at two Foot di&longs;tance from the out­<lb/>&longs;ide of the Receiver. </s> <s>And this Experi­<lb/>ment being reiterated in another place, <lb/>&longs;ucceded after the like manner. </s> <s>Which <lb/>&longs;eems to prove, that whether or no the <lb/>Air be the onely, it is at lea&longs;t, the princi­<lb/>pal medium of Sounds. </s> <s>And by the way <lb/>it is very well worth noting, that in a Ve&longs;­<lb/>&longs;el &longs;o well clo&longs;'d as our Receiver, &longs;o weak <lb/>a pul&longs;e as that of the ballance of a Watch <lb/>&longs;hould propagate a motion to the Ear in a <lb/>Phi&longs;ically &longs;traight Line, notwith&longs;tanding <lb/>the interpo&longs;ition of &longs;o clo&longs;e a Body as <lb/>Gla&longs;s, e&longs;pecially Gla&longs;s of &longs;uch thickne&longs;s <lb/>as that of our Receiver; &longs;ince by this it <lb/>&longs;eems that the air impri&longs;on'd in the Gla&longs;s, <lb/>mu&longs;t, by the motion of the ballance, be <lb/>made to beat again&longs;t the concave part of <lb/>the Receiver, &longs;trongly enough to make <lb/>its convex part beat upon the contiguous <lb/>Air, and &longs;o propagate the motion to the <lb/>Li&longs;tners ears. </s> <s>I know this cannot but <lb/>&longs;eem &longs;trange to tho&longs;e, who, with an emi­<lb/>nent Modern Philo&longs;opher, will not allow <lb/>that a Sound, made in the cavity of a <lb/>Room, or other place &longs;o clo&longs;'d, that there <pb xlink:href="013/01/239.jpg" pagenum="209"/>is no intercour&longs;e betwixt the external and <lb/>internal Air, can be heard by tho&longs;e with­<lb/>out, unle&longs;s the &longs;ounding Body do imme­<lb/>diately &longs;trike again&longs;t &longs;ome part of the in­<lb/>clo&longs;ing Body. </s> <s>But not having now time <lb/>to handle Controver&longs;ies, we &longs;hall onely <lb/>annex, That after the foregoing Experi­<lb/>ment, we took a Bell of about two Inches <lb/>in Diameter at the bottom, which was <lb/>&longs;upported in the mid&longs;t of the cavity of <lb/>the Receiver by a bent &longs;tick, which by <lb/>rea&longs;on of its Spring pre&longs;&longs;'d with its two <lb/>ends again&longs;t the oppo&longs;ite parts of the in­<lb/>&longs;ide of the Ve&longs;&longs;el: in which, when it was <lb/>clo&longs;'d up, we ob&longs;erv'd that the Bell &longs;eem'd <lb/>to &longs;ound more dead then it did when ju&longs;t <lb/>before it &longs;ounded in the open Air. </s> <s>And <lb/>yet, when afterwards we had as formerly <lb/>emptyed the Receiver, we could not di&longs;­<lb/>cern any con&longs;iderable change (for &longs;ome <lb/>&longs;aid they ob&longs;erv'd a &longs;mall one) in the loud­<lb/>ne&longs;s of the &longs;ound, whereby it &longs;eem'd that <lb/>though the Air be the principal medium <lb/>of &longs;ound, yet either a more &longs;ubtle mat­<lb/>ter may be al&longs;o a medium of it, or el&longs;e an <lb/>ambient Body that contains but very <lb/>few particles of Air, in compari&longs;on of <lb/>tho&longs;e it is ea&longs;ily capable of, is &longs;ufficient <lb/>for that purpo&longs;e. </s> <s>And this, among o-<pb xlink:href="013/01/240.jpg" pagenum="210"/>ther things, invited us to con&longs;ider, whether <lb/>in the above-mention'd Experiment made <lb/>with the Bell and the Load-&longs;tone, there <lb/>might not in the de&longs;erted part of the Tube <lb/>remain Air enough to produce a &longs;ound: <lb/>&longs;ince the Tubes for the Experiment <emph type="italics"/>De <lb/>Vacuo<emph.end type="italics"/> (not to mention the u&longs;ual thin­<lb/>ne&longs;s of the Gla&longs;s) being &longs;eldom made <lb/>greater then is requi&longs;ite, a little Air might <lb/>bear a not incon&longs;iderable proportion to <lb/>the de&longs;erted &longs;pace. </s> <s>And that al&longs;o, in the <lb/>Experiment <emph type="italics"/>De Vacuo,<emph.end type="italics"/> as it is wont to be <lb/>made, there is generally &longs;ome little Air <lb/>that gets in from without, or at lea&longs;t &longs;tore <lb/>of bubbles that ari&longs;e from the Body of <lb/>the Quick-&longs;ilver, or other Liquor it &longs;elf, <lb/>Ob&longs;ervations heedfully made have fre­<lb/>quently informed us: And it may al&longs;o <lb/>appear, by what has been formerly deli­<lb/>vered concerning the <emph type="italics"/>Torricellian<emph.end type="italics"/> Experi­<lb/>ment. </s></p><p type="margin"> <s><margin.target id="marg34"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 27.</s></p><p type="main"> <s>On the occa&longs;ion of this Experiment <lb/>concerning &longs;ounds, we may adde in this <lb/>place, That when we try'd the Experiment <lb/>formerly mention'd, of firing Gun-pow­<lb/>der with a Pi&longs;tol in our evacuated Recei­<lb/>ver, the noi&longs;e made by the &longs;triking of the <lb/>Flint again&longs;t the Steel, was exceeding <lb/>languid in compari&longs;on of what it would <pb xlink:href="013/01/241.jpg" pagenum="211"/>have been in the open Air. </s> <s>And on di­<lb/>vers other occa&longs;ions it appear'd that the <lb/>&longs;ounds created within our exhau&longs;ted <lb/>Gla&longs;s, if they were not lo&longs;t before they <lb/>reach'd the Ear, &longs;eem'd at lea&longs;t to arrive <lb/>there very much weaken'd. </s> <s>We intended <lb/>to try whether or no the Wire-&longs;tring of an <lb/>In&longs;trument &longs;hut up into our Receiver, <lb/>would, when the ambient Air was &longs;uck'd <lb/>out, at all tremble, if in another In&longs;trument <lb/>held clo&longs;e to it, but without the Receiver <lb/>a &longs;tring tun'd (as Mu&longs;icians &longs;peak, how <lb/>properly I now examine not) to an Uni&longs;on <lb/>with it, were briskly toucht, and &longs;et a Vi­<lb/>brating. </s> <s>This, I &longs;ay, we purpo&longs;'d to try <lb/>to &longs;ee how the motion made in the Air <lb/>without, would be propagated through the <lb/>cavity of our evacuated Receiver. </s> <s>But <lb/>when the In&longs;trument wherewith the tryal <lb/>was to be made came to be imploy'd, it <lb/>prov'd too big to go into the Pneumatical <lb/>Ve&longs;&longs;el, and we have not now the conveni­<lb/>ency to have a fitter made. </s></p><p type="main"> <s>We thought likewi&longs;e to convey into <lb/>the Receiver a long and &longs;lender pair of <lb/>Bellows, made after the fa&longs;hion of tho&longs;e <lb/>u&longs;ually employ'd to blow Organs, and fur­<lb/>ni&longs;h'd with a &longs;mall Mu&longs;ical in&longs;tead of an <pb xlink:href="013/01/242.jpg" pagenum="212"/>ordinary Pipe. </s> <s>For we hop'd, that by <lb/>means of a &longs;tring fa&longs;tned to the upper <lb/>part of the Bellows, and to the moveable <lb/>&longs;topple that makes a part of the Cover <lb/>of our Receiver, we &longs;hould, by frequent­<lb/>ly turning round that &longs;topple, and the an­<lb/>nexed &longs;tring, after the manner already <lb/>often recited, be able to lift up and di&longs;tend <lb/>the Bellows; and by the help of a com­<lb/>petent weight fa&longs;ten'd to the &longs;ame upper <lb/>part of the Bellows, we &longs;hould likewi&longs;e <lb/>be able, at plea&longs;ure, to compre&longs;s them: <lb/>and by con&longs;equence, try whether that <lb/>&longs;ubtler matter then Air (which, accord­<lb/>ing to tho&longs;e that deny a <emph type="italics"/>Vacuum,<emph.end type="italics"/> mu&longs;t be <lb/>&longs;uppo&longs;'d to fill the exhau&longs;ted Receiver) <lb/>would be able to produce a &longs;ound in the <lb/>Mu&longs;ical Pipe; or in a Pipe like that of or­<lb/>dinary Bellows, to beget a Wind capable <lb/>to turn or &longs;et a moving &longs;ome very light <lb/>matter, either &longs;hap'd like the Sails of a <lb/>Wind-Mill, or of &longs;ome other conveni­<lb/>ent form, and expo&longs;'d to its Orifice. </s> <s>This <lb/>Experiment, I &longs;ay, we thought to make, <lb/>but have not yet actually made it for want <lb/>of an Artificer to make us &longs;uch a pair of <lb/>Bellows as it requires. </s></p><p type="main"> <s>We had thoughts al&longs;o of trying whe­<lb/>ther or no, as Sounds made by Bodies in <pb xlink:href="013/01/243.jpg" pagenum="213"/>our Receiver become much more languid <lb/>then ordinary, by rea&longs;on of the want of <lb/>Air, &longs;o they would grow &longs;tronger, in ca&longs;e <lb/>there were an unu&longs;ual quantity of Air <lb/>crouded and &longs;hut up in the &longs;ame Ve&longs;&longs;el, <lb/>which may be done (though not without <lb/>&longs;ome difficulty) by the help of the Pump, <lb/>provided the Cover and Stopple be &longs;o <lb/>firmly fa&longs;ten'd (by binding and Cement, <lb/>or otherwi&longs;e) to the Gla&longs;s; and to each <lb/>other, that there be no danger of the <lb/>conden&longs;'d Airs blowing of either of them <lb/>away, or its breaking through the jun­<lb/>ctures. </s> <s>The&longs;e thoughts, My Lord, as I <lb/>was &longs;aying, we entertain'd; but for want <lb/>of lea&longs;ure, as, of as good Receivers as <lb/>ours, to &longs;ub&longs;titute in its place, in ca&longs;e we <lb/>&longs;hould break it before we learn'd the skill <lb/>of condencing the Air in it, we dur&longs;t not <lb/>put them in practice: Yet, on this occa­<lb/>&longs;ion, give me leave to adverti&longs;e Your <lb/>Lord&longs;hip once for all, That though for <lb/>the rea&longs;ons newly intimated, we have, <lb/>Onely in the &longs;eventeenth Experiment, <lb/>taken notice, that by the help of our En­<lb/>gine the Air may be conden&longs;'d as well as <lb/>rarified; yet there are divers other of our <lb/>Experiments, who&longs;e <emph type="italics"/>Phænomena<emph.end type="italics"/> it were <pb xlink:href="013/01/244.jpg" pagenum="214"/>worth while to try to vary, by means of <lb/>the compre&longs;&longs;ion of the Air. </s></p><p type="main"> <s>WE taught, among divers other <lb/><arrow.to.target n="marg35"/><lb/>things, when we di&longs;cour&longs;'d of our <lb/>fir&longs;t Experiment, That the Air &longs;hut up in <lb/>our Receiver, pre&longs;&longs;eth as &longs;trongly upon <lb/>the Bodies &longs;hut up with it, as if they <lb/>were expo&longs;'d to the pre&longs;&longs;ure of the whole <lb/>Atmo&longs;phere. </s> <s>That this was not incon­<lb/>&longs;iderately propounded, we hope Your <lb/>Lord&longs;hip has gather'd from divers of the <lb/>things already recited: But yet perhaps it <lb/>will not be ami&longs;s to &longs;ubjoyn, by way of <lb/>further confirmation of the &longs;ame truth, the <lb/>following Experiment, which &longs;hould have <lb/>accompanied the 20<emph type="sup"/>th<emph.end type="sup"/>, but the Paper where <lb/>in the one was written chanc'd not to beat <lb/>hand, when the other was &longs;ent away. </s></p><p type="margin"> <s><margin.target id="marg35"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 28.</s></p><p type="main"> <s>We convey'd into the Receiver a new <lb/>Gla&longs;s Viol, capable of holding about 6 or <lb/>7 ounces of Water, into which we had <lb/>before put 2 or 3 Spoon-fulls of that Li­<lb/>quor, and &longs;topt it clo&longs;e with a fit Cork. <lb/></s> <s>The Pneumatical Ve&longs;&longs;el being empty'd, <lb/>there appear'd not any change in the in­<lb/>clo&longs;'d Water, the Air impri&longs;on'd with it, <lb/>not having the force to blow out the &longs;top-<pb xlink:href="013/01/245.jpg" pagenum="215"/>ple, which event, though it were no other <lb/>then we expected, was differing from what <lb/>we de&longs;ir'd. </s> <s>For we would gladly have &longs;een <lb/>what change would have appear'd in the <lb/>Water upon the Bottles being &longs;uddenly <lb/>un&longs;topp'd, in a place where the ambient <lb/>Body was &longs;o differing from our common <lb/>Air. </s> <s>Wherefore we did again put in the <lb/>Viol, but le&longs;s &longs;trongly clo&longs;'d then for­<lb/>merly, though as &longs;trongly &longs;topt as &longs;eem'd <lb/>requi&longs;ite on ordinary occa&longs;ions: But when <lb/>the Air was pump'd out of the Receiver, <lb/>that within the Viol did quickly, as we <lb/>expected, find or make it &longs;elf little pa&longs;&longs;a­<lb/>ges to get out at: as we argu'd, from this, <lb/>That whereas when the Viol was put in <lb/>the time before, the Water remain'd all <lb/>the while perfectly free from bubbles; at <lb/>this time the bottom of the Gla&longs;s ap­<lb/>pear'd all cover'd with them, and they, <lb/>upon the regre&longs;s of the excluded Air into <lb/>the Receiver, did pre&longs;ently flag and &longs;hrink <lb/>up. </s></p><p type="main"> <s>From the&longs;e tryals it &longs;eem'd deducible <lb/>enough, that whil'&longs;t the Viol continu'd <lb/>to be well &longs;topt, the included Water <lb/>did, from the Air, &longs;hut up with it, <lb/>&longs;u&longs;tain a pre&longs;&longs;ure equal to that of the <lb/>Atmo&longs;phere; &longs;ince till the Air could get <pb xlink:href="013/01/246.jpg" pagenum="216"/>out of the Gla&longs;s, there appear'd no bub­<lb/>bles in the Water, notwith&longs;tanding the <lb/>want of pre&longs;&longs;ure in the ambient Body. </s></p><p type="main"> <s>But to be &longs;ure to reach the chief end of <lb/>our Experiment, we made u&longs;e of this o­<lb/>ther expedient: We cau&longs;'d a convenient <lb/>quantity of Water to be put, and Her­<lb/>metically &longs;hut up into a Gla&longs;s Egge, to <lb/>who&longs;e long Neck (which was purpo&longs;ely <lb/>made of an unequal thickne&longs;s) was fa­<lb/>&longs;ten'd to one end of a &longs;tring, who&longs;e o­<lb/>ther end was ty'd to the Cover of our <lb/>Receiver, after the manner el&longs;ewhere men­<lb/>tion'd already: Then the Egge being <lb/>convey'd into the Pneumatical Ve&longs;&longs;el, <lb/>and that being evacuated, we did, by <lb/>turning the bra&longs;s Stopple formerly de­<lb/>&longs;crib'd among&longs;t the parts of our En­<lb/>gine, &longs;o &longs;horten the &longs;tring as to break the <lb/>Gla&longs;s; whereby liberty being given to <lb/>the Air impri&longs;on'd in the Egge, to pa&longs;s <lb/>into the capacity of the Receiver, the &longs;ud­<lb/>den rece&longs;s of the Air made the bubbles in <lb/>a trice appear &longs;o numerous, and a&longs;cend <lb/>&longs;o &longs;wiftly in the Water, that their motion <lb/>look'd like that of a violent &longs;hower of <lb/>Rain; &longs;ave that the bubbles did not, like <lb/>the drops of Rain, tend downwards, but <lb/>upwards, which made me re&longs;emble this <pb xlink:href="013/01/247.jpg" pagenum="217"/><emph type="italics"/>Phænomenon<emph.end type="italics"/> to what I have &longs;een happen <lb/>in the di&longs;&longs;olution of Seed-Pearl in &longs;ome <lb/>acid <emph type="italics"/>Men&longs;truum,<emph.end type="italics"/> in which, if a good quan­<lb/>tity of the little Pearls be ca&longs;t whole, they <lb/>will at fir&longs;t, if the <emph type="italics"/>Men&longs;truum<emph.end type="italics"/> be &longs;harp e­<lb/>nough, be carryed in &longs;warms from the <lb/>bottom to the top of the Liquor. </s> <s>We <lb/>will adde, that without &longs;ealing up the <lb/>Gla&longs;s, this Experiment may be try'd in <lb/>one of our &longs;malle&longs;t Receivers, for there <lb/>the ex&longs;uction of the ambient Air may be <lb/>perform'd &longs;o nimbly, that immediately <lb/>the bubbles lurking in the Water are al­<lb/>low'd to di&longs;play them&longs;elves, and a&longs;cend <lb/>in throngs; in&longs;omuch, as having in &longs;uch <lb/>a Receiver try'd the Experiment with <lb/>Wine (as a more &longs;pirituous Liquor) in­<lb/>&longs;tead of Water, the Red-Wine appear'd <lb/>all cover'd, with a copious, but vani&longs;hing <lb/>white Froth, almo&longs;t as if a Ve&longs;&longs;el full of <lb/>bottl'd drink had been unwarily open'd. </s></p><p type="main"> <s>IT may not a little conduce to the clear­<lb/><arrow.to.target n="marg36"/><lb/>er explication of divers Points in the <lb/>Doctrine of Meteors, and perhaps of <lb/>&longs;ome other Phy&longs;iological difficulties, to <lb/>di&longs;cover what the Air does to the motion <lb/>of tho&longs;e Steams or Exhalations that a&longs;-<pb xlink:href="013/01/248.jpg" pagenum="218"/>cend into it, namely, Whether they mount <lb/>upwards by vertue of any &longs;uch <emph type="italics"/>po&longs;itive le­<lb/>vity<emph.end type="italics"/> (as &longs;ome Peripateticks &longs;peak) ac­<lb/>quir'd together with their Aërial nature, <lb/>as inables them to pierce through part of <lb/>the Atmo&longs;phere, and over-come its re­<lb/>&longs;i&longs;tance. </s> <s>Or el&longs;e, whether the&longs;e &longs;teams <lb/>being once rai&longs;'d above the Earth by their <lb/>agitation, have their a&longs;cent and &longs;u&longs;tenta­<lb/>tion aloft, rather promoted then hindred <lb/>by the Air: as the inferior parts of that, <lb/>being thicker and heavier then the &longs;upe­<lb/>rior, the &longs;teams can more ea&longs;ily continue <lb/>for a while their agitation upwards then <lb/>downwards; And afterwards are by the <lb/>&longs;ame fluidity and thickne&longs;s of the Air, <lb/>carried to and fro in it, and kept from re­<lb/>lap&longs;ing to the Earth, as in the Sea water <lb/>the &longs;aline parts are kept from &longs;ub&longs;iding by <lb/>tho&longs;e aqueous ones wherewith they are <lb/>a&longs;&longs;ociated. </s></p><p type="margin"> <s><margin.target id="marg36"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 29</s></p><p type="main"> <s>We hop'd to illu&longs;trate this matter, by <lb/>ob&longs;erving the motion of the &longs;moke, pro­<lb/>ceeding from kindled or flaming Bodies in <lb/>our exhau&longs;ted Receiver. </s> <s>But as we for­<lb/>merly noted, upon the ex&longs;uction of the <lb/>Air, the &longs;moking of tho&longs;e Bodies pre­<lb/>&longs;ently cea&longs;'d. </s> <s>We had thoughts al&longs;o of <lb/>conveying into our Pneumatical Gla&longs;s a <pb xlink:href="013/01/249.jpg" pagenum="219"/>hot Iron, with &longs;ome Body ea&longs;ie to be <lb/>di&longs;&longs;ipated into &longs;moke &longs;et upon it, but con­<lb/>&longs;ider'd, that neither was that way free <lb/>from inconveniencies; e&longs;pecially this, that <lb/>the hot Body would make the Impri&longs;on'd <lb/>Air circulate within the Receiver, and <lb/>con&longs;equently make it que&longs;tionable whe­<lb/>ther the a&longs;cent of the &longs;teams would not <lb/>be due to the new and acquired motion of <lb/>the Air. </s></p><p type="main"> <s>Wherefore I bethought my &longs;elf of an­<lb/>other way to &longs;atisfie in &longs;ome mea&longs;ure my <lb/>curio&longs;ity, to wit, by means of a certain <lb/>Liquor, which I call'd to minde that &longs;ome <lb/>years ago I had (for a de&longs;ign that belongs <lb/>not to our pre&longs;ent purpo&longs;e) prepar'd; <lb/>which, I &longs;uppo&longs;e, I &longs;hew'd Your Lord­<lb/>&longs;hip, and which had the luck to be ta­<lb/>ken notice of by divers very Ingenious <lb/>and Famous Men. </s> <s>For this Liquor, <lb/>though mo&longs;t of its Ingredients be Metals, <lb/>and all of them ponderous enough, is yet <lb/>of that nature, that whil&longs;t the Viol where­<lb/>in it is kept is &longs;topt (how &longs;light a Cover <lb/>&longs;oever) both the Liquor and the Gla&longs;s <lb/>are tran&longs;parent; and &longs;o is that upper half <lb/>of the Gla&longs;s to which the Liquor reaches <lb/>not. </s> <s>But a&longs;&longs;oon as ever the &longs;topple is ta­<lb/>ken out, and full acce&longs;s is given to the ex-<pb xlink:href="013/01/250.jpg" pagenum="220"/>ternal Air, both the inward part of the <lb/>Cork, and the Liquor it &longs;elf, do pre&longs;ent­<lb/>ly &longs;end upwards, and &longs;catter abroad a <lb/>fume as thick and white, as if there were <lb/>a quantity of Alabla&longs;ter-du&longs;t thrown up <lb/>into the Air: And this &longs;moking of the <lb/>Liquor la&longs;ts till my unwillingne&longs;s to wa&longs;te <lb/>it, invites me &longs;top it again; and then the <lb/>a&longs;cen&longs;ion of the fumes &longs;uddenly cea&longs;es, till <lb/>the Viol be again un&longs;top'd. </s></p><p type="main"> <s>This fuming Liquor then I thought <lb/>would much conduce to the di&longs;covery I <lb/>de&longs;ir'd to make, &longs;ince it &longs;av'd me the need <lb/>of conveying any hot Body with it into <lb/>the Receiver, and would not darken it <lb/>with fumes before the time. </s> <s>Wherefore <lb/>having ty'd to the Viol a great weight of <lb/>Lead, to keep it from being lifted up by <lb/>the drawing out of the Cork; and having <lb/>ty'd to the &longs;topple one end of a &longs;tring, of <lb/>which the other end was made fa&longs;t to the <lb/>Cover of the Pneumatical Gla&longs;s, the Li­<lb/>quor was carefully clo&longs;'d up after the <lb/>wonted manner; then the Air being dili­<lb/>gently pump'd out, the Viol was un&longs;topt <lb/>in the empty'd Receiver: and though <lb/>immediately, npon the drawing out of the <lb/>Cork, there appear'd to be as it were <lb/>thrown up &longs;ome white fumes, which <pb xlink:href="013/01/251.jpg" pagenum="221"/>&longs;eem'd to proceed from the Air before <lb/>impri&longs;on'd in the Viol, and diffu&longs;ing it <lb/>&longs;elf &longs;uddenly into the capicity of the <lb/>Receiver. </s> <s>Yet we afterward ob&longs;erv'd, <lb/>as we expected, That the fumes did not <lb/>mount and di&longs;per&longs;e them&longs;elves as they <lb/>u&longs;e to do in the open Air, but that, when <lb/>by rea&longs;on of the agitation of the Cor­<lb/>pu&longs;cles of the Liquor, which could not <lb/>continue their motion in &longs;o narrow a <lb/>&longs;pace as the Viol afforded them, and were <lb/>therefore reduc'd to thru&longs;t one another <lb/>out of it; when, I &longs;ay, by the&longs;e a&longs;&longs;i­<lb/>&longs;tances the fumes were a&longs;cended to the lip <lb/>of the Viol, they mounted no higher, <lb/>but ran down along the out-&longs;ide of the <lb/>Viol to the bottom of it; and thence <lb/>along, a long and inclining piece of Lead, <lb/>on which the Viol re&longs;ted, like a little <lb/>Stream (not very much bigger then a <lb/>Swans Quill) who&longs;e nature it &longs;eemd to e­<lb/>mulate &longs;o well, that it quitted not the Viol <lb/>till it was come to the bottom of it, and <lb/>then for&longs;ook it in &longs;uch a manner as a <lb/>&longs;tream of Water of the &longs;ame bigne&longs;s <lb/>would have done. </s> <s>And this &longs;tream la&longs;ted <lb/>a pretty while, and would probably have <lb/>la&longs;ted longer, but that being loath to wa&longs;te <lb/>my Liquor, I let in at the Stop-cock a <pb xlink:href="013/01/252.jpg" pagenum="222"/>pretty deal of the external Air; notwith­<lb/>&longs;tanding which, finding after a while the <lb/>&longs;tream did run afre&longs;h; though, as it &longs;eem'd, <lb/>not altogether &longs;o copious as before: I let <lb/>as much more Air, as would, come in, and <lb/>found (&longs;omewhat to my wonder) that <lb/>though the &longs;tream formerly mention'd <lb/>di&longs;-appear'd, yet there appear'd not any <lb/>white fumes to ari&longs;e, either from the Cork, <lb/>or out of the Viol it &longs;elf, no not when <lb/>the Cover was remov'd from the Recei­<lb/>ver; though not onely after a while there <lb/>a&longs;cended white Fumes from the Receiver: <lb/>but having forthwith taken out the Viol <lb/>into the open Air, it emitted white ex­<lb/>halations as before; and having pre&longs;ently <lb/>after un&longs;top'd it in an open Window, we <lb/>found both it and the Cork immediatly <lb/>to &longs;end forth a yet much more plentiful <lb/>&longs;moak. </s> <s>Though it be now divers years <lb/>&longs;ince this Numerical Liquor was prepa­<lb/>red, after the manner mention'd either <lb/>by <emph type="italics"/>Carneiades<emph.end type="italics"/> or <emph type="italics"/>Eleutherius<emph.end type="italics"/> (for I do not <lb/>well remember which) in tho&longs;e Dialogues <lb/>concerning Heat and Flame that have a­<lb/>bove been mention'd. </s></p><p type="main"> <s>More Circum&longs;tances concerning the&longs;e <lb/>Fumes we might have ob&longs;erv'd, had we <lb/>not been deterr'd by an Indi&longs;po&longs;ition in <pb xlink:href="013/01/253.jpg" pagenum="223"/>point of health, from having much to do <lb/>with &longs;teams of &longs;o dangerous a nature, as by <lb/>that of the Ingredients of this Liquor <lb/>the&longs;e &longs;eem likely to be of. </s></p><p type="main"> <s>The Reflections that may be made up­<lb/>on this Experiment, we have not now the <lb/>lea&longs;ure to pro&longs;ecute, and therefore &longs;hall <lb/>content our &longs;elves to recommend the &longs;e­<lb/>veral Circum&longs;tances of it to Your Lord­<lb/>&longs;hips &longs;erious con&longs;ideration; and to take <lb/>notice <emph type="italics"/>(en pa&longs;&longs;ant)<emph.end type="italics"/> that &longs;teams in an am­<lb/>bient Body, or a medium thinner then <lb/>them&longs;elves, may both tend downwards, <lb/>and otherwi&longs;e emulate the nature of a <lb/>Liquor; which I therefore point at, that <lb/>it may appear the le&longs;s &longs;trange, if we &longs;ome­<lb/>times &longs;peak of the Atmo&longs;phere as of a <lb/>kinde of Liquor, in compari&longs;on of that <lb/>more thin and &longs;ubtle Cele&longs;tial Matter that <lb/>&longs;urrounds it. </s></p><p type="main"> <s>And though it might perchance &longs;uf­<lb/>fice to have on this occa&longs;ion intima­<lb/>ted thus much; yet, le&longs;t this way <lb/>of &longs;peaking of the Atmo&longs;phere &longs;hould <lb/>be thought too bold and extra­<lb/>vagant, I am content to borrow an <lb/>Experiment of the Di&longs;cour&longs;e former-<pb xlink:href="013/01/254.jpg" pagenum="224"/>ly mention'd (touching fluidity and firm­<lb/>ne&longs;s) and &longs;ubjoyn it here with alterations <lb/>&longs;uitable to the contrivance of our Engine; <lb/>and this the rather, becau&longs;e I hope it may <lb/>conduce to the di&longs;covery of the nature of <lb/>the Atmo&longs;phere: for which rea&longs;on it <lb/>might have been annext to what has been <lb/>noted either upon the fir&longs;t, or eighteenth <lb/>Experiment, but that when they were <lb/>written and &longs;ent away, it came not into <lb/>my minde. </s> <s>The Experiment then as we <lb/>try'd in our Engine, was as follows. </s></p><p type="main"> <s>WE took one of the &longs;mall Receivers, <lb/><arrow.to.target n="marg37"/><lb/>often mention'd already, and into it <lb/>we convey'd a piece of well lighted Match; <lb/>and letting it remain there till it had fill'd <lb/>the Receiver with &longs;moak, we took it out <lb/>and ha&longs;tily clo&longs;'d again the Receiver, that <lb/>the &longs;moak might not get away. </s> <s>Then <lb/>&longs;taying awhile to let the&longs;e fumes lei&longs;urely <lb/>&longs;ub&longs;ide, we found, as we expected, that <lb/>after &longs;ome time they &longs;etled them&longs;elves in <lb/>the lower half of the Receiver, in a dark­<lb/>i&longs;h Body, leaving the upper half of the <lb/>Receiver tran&longs;parent, and as to &longs;ight, full <lb/>of nought but clear Air. </s> <s>Now to mani­<lb/>fe&longs;t that this &longs;moak thus &longs;etled emulated <pb xlink:href="013/01/255.jpg" pagenum="225"/>a Liquor, we inclin'd the Engine that con­<lb/>tain'd it, &longs;ometimes to one &longs;ide, and &longs;ome­<lb/>times to the other; and ob&longs;erv'd the <lb/>&longs;moak to keep its &longs;urface almo&longs;t Hori­<lb/>zontal, notwith&longs;tanding the &longs;tooping of <lb/>the Ve&longs;&longs;el that held it, as Water or an­<lb/>other Liquor would in the like ca&longs;e have <lb/>done. </s> <s>And if by a quicker rocking of the <lb/>Engine the &longs;moke were more &longs;wiftly &longs;ha­<lb/>ken, it would, like Water, either Vibrate <lb/>to and fro from one &longs;ide to the other of <lb/>the Gla&longs;s, or el&longs;e have its &longs;urface manife&longs;t­<lb/>ly curll'd with Waves, but pre&longs;erve its <lb/>&longs;elf in an intire and di&longs;tinct Body from the <lb/>incumbent Air; and being permitted to <lb/>re&longs;t awhile, would &longs;oon recover its for­<lb/>mer &longs;mooth and level <emph type="italics"/>&longs;uperficies:<emph.end type="italics"/> If al&longs;o <lb/>the Key were turn'd and the Valve un­<lb/>&longs;topp'd, &longs;o that there was a free, though <lb/>but a narrow pa&longs;&longs;age open'd betwixt the <lb/>external Air and the cavity of the Recei­<lb/>ver, then would &longs;ome of this &longs;moak fall <lb/>down, as it were, in a &longs;tream into the &longs;ub­<lb/>jacent Cylinder, and a proportionate <lb/>quantity of the outward Air, would ma­<lb/>nife&longs;tly a&longs;cend through it into the incum­<lb/>bent Air, much after the &longs;ame manner as <lb/>if you invert a Viol with a long Neck, and <lb/>well fill'd with Red-Wine, into a Gla&longs;s <pb xlink:href="013/01/256.jpg" pagenum="226"/>full of fair water, you &longs;hall &longs;ee the Water <lb/>and Wine by degrees mingle with one an­<lb/>other; the one falling downe as it were in <lb/>little colour'd &longs;treames, and the other a&longs;­<lb/>cending into its room in the like curled <lb/>&longs;treames, &longs;ometimes preceded by round <lb/>parcels of water, which, by rea&longs;on of their <lb/>tran&longs;parency, looke almo&longs;t like bubbles. <lb/></s> <s>The other circum&longs;tances of this Experi­<lb/>ment, belonging not all of them to our <lb/>pre&longs;ent purpo&longs;e, we &longs;hall content our <lb/>&longs;elves with taking notice of one which <lb/>&longs;eemes the mo&longs;t important, and may illu­<lb/>&longs;trate and confirme &longs;ome things former­<lb/>ly delivered. </s> <s>And it was, That if, when <lb/>the <emph type="italics"/>&longs;uperficies<emph.end type="italics"/> of our Smoke lay &longs;mooth <lb/>and horizontal, a hot iron were held near <lb/>the our &longs;ide of the Receiver, the Neigh­<lb/>bouring part of the included fumes (for <lb/>the re&longs;t did not very much alter their for­<lb/>mer <emph type="italics"/>&longs;uperficies<emph.end type="italics"/>) being rarified by the heat, <lb/>would readily a&longs;cend in a large Pillar of <lb/>&longs;moke to the very top of the Receiver, <lb/>yet without &longs;eeming to loo&longs;e a di&longs;tinct <lb/><emph type="italics"/>&longs;uperficies,<emph.end type="italics"/> or to be confounded with Air; <lb/>below which, upon the rece&longs;s of the ad­<lb/>ventitious heat that by agitating it im­<lb/>pell'd it upward, it would againe &longs;ub­<lb/>&longs;ide. </s></p><pb xlink:href="013/01/257.jpg" pagenum="227"/><p type="margin"> <s><margin.target id="marg37"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 30.</s></p><p type="main"> <s>All which being added to the late Ex­<lb/>periment of the &longs;moking Liquor, and <lb/>to what may be from that which has been <lb/>el&longs;ewhere &longs;ayd, gather'd to the &longs;ame pur­<lb/>po&longs;e, will, I hope, keep it at lea&longs;t from ap­<lb/>pearing ab&longs;ur'd: If &longs;ince we &longs;ee that there <lb/>is &longs;o great an inequality in the den&longs;ity and <lb/>weight of Liquors, that water is neere 14 <lb/>times thinner or lighter than Quick-&longs;ilver <lb/>of the &longs;ame bulk, and well dephlegm'd; <lb/>Spirit of Wine yet much lighter than wa­<lb/>ter; we venter to &longs;peak &longs;ometimes of the <lb/>Atmo&longs;phere, as if it were a peculiar kind <lb/>of thin and halituous Liquor (if I may &longs;o <lb/>call it) much lighter than Spirit of Wine. </s></p><p type="main"> <s>To the&longs;e things I know not whether it <lb/>will be requi&longs;ite to add, that as we late­<lb/>ly took notice of con&longs;picuous waves that <lb/>appear'd upon the <emph type="italics"/>&longs;uperficies<emph.end type="italics"/> of our agi­<lb/>tated &longs;moke. </s> <s>So &longs;ome &longs;uch thing may <lb/>not ab&longs;urdly be conjectur'd to happen <lb/>on the <emph type="italics"/>&longs;uperficies<emph.end type="italics"/> of the Atmo&longs;phere, <lb/>by tho&longs;e &longs;trange ruggedne&longs;&longs;es that ap­<lb/>peare (e&longs;pecially in the Spring and Fall, <lb/>when exhalations and vapours are wont to <lb/>a&longs;cend mo&longs;t plentifully) upon the Limb <lb/>or Edge of the Ri&longs;ing and Setting Sun. </s> <s>I <lb/>&longs;peake thus diffidently upon this occa&longs;ion <lb/>becau&longs;e I know that by the Fluctuation or <pb xlink:href="013/01/258.jpg" pagenum="228"/>Boyling of the Sun's own <emph type="italics"/>&longs;uperficies<emph.end type="italics"/> di­<lb/>ver&longs;e eminent Mathematicians have plau­<lb/>&longs;ibly enough (but how truly I leave <lb/>your Lord&longs;hip to Judge) endeavour'd to <lb/>give an Account of it. </s> <s>But if we will joine <lb/>with tho&longs;e that have a&longs;crib'd of late this <lb/><emph type="italics"/>Phænomenon<emph.end type="italics"/> to the Refraction the Sun­<lb/>Beames fuffer in our vapid Air; we may, <lb/>as hath been intimated, promote their Do­<lb/>ctrin by deducing from it, that probably <lb/>the &longs;urface Atmo&longs;phere is oftentimes (if <lb/>not alwayes) exceedingly curl'd or wav'd. <lb/></s> <s>And certainly it is &longs;omewhat wonderfull <lb/>as well as very plea&longs;ant to behold, how, <lb/>to him that looks upon the &longs;etting Sun <lb/>through a long & excellent Tele&longs;cope, <lb/>there will not only appeare &longs;trange ine­<lb/>qualities in the edge of it (in&longs;omuch that <lb/>I have often &longs;een it more indented than a <lb/>Saw) but tho&longs;e inequalities will vani&longs;h in <lb/>one place and pre&longs;ently appeare in ano­<lb/>ther, and &longs;eem perfectly to move like <lb/>waves &longs;ucceeding and de&longs;troying one an­<lb/>other; &longs;ave that their Motion oftentimes <lb/>&longs;eemes to be quicke&longs;t as if in that va&longs;t &longs;ea <lb/>they were carried on by a current, or at <lb/>lea&longs;t by a tide. </s> <s>And this (as we el&longs;e <lb/>where note) appear's to the eye not on­<lb/>ly when it looks directly through the te-<pb xlink:href="013/01/259.jpg" pagenum="229"/>le&longs;cope upon the &longs;unne; but al&longs;o when a <lb/>large and well defin'd image of the &longs;unne <lb/>is by the &longs;ame tele&longs;cope brought into a <lb/>roome and ca&longs;t upon a &longs;heet of white pa­<lb/>per. </s> <s>But to in&longs;i&longs;t on this were to digre&longs;s: <lb/>and therefore I will proceed to experi­<lb/>ments of another kind. </s></p><p type="main"> <s>IT has been admir'd by very ingenious <lb/><arrow.to.target n="marg38"/><lb/>Men, that if the exqui&longs;itly poli&longs;h'd <lb/>&longs;urfaces of two flat peeces of marble be &longs;o <lb/>congruous to each other that from their <lb/>mutuall application there will re&longs;ult an <lb/>immediate contact, they will &longs;tick &longs;o fa&longs;t <lb/>together, that he that lifts up the upper­<lb/>mo&longs;t, &longs;hall, if the undermo&longs;t be not ex­<lb/>ceeding heavy, lift up that too, and &longs;u&longs;­<lb/>taine it aloft in the free aire. </s> <s>A proba­<lb/>ble cau&longs;e of this &longs;o clo&longs;e adhe&longs;ion we have <lb/>el&longs;ewhere endeavour'd to deduce from the <lb/>unequall pre&longs;&longs;ure of the Air upon the un­<lb/>dermo&longs;t &longs;tone; For the lower <emph type="italics"/>&longs;uperficies<emph.end type="italics"/><lb/>of that &longs;tone being freely expos'd to the <lb/>Air is pre&longs;&longs;'d upon by it, whereas the up­<lb/>permo&longs;t &longs;urface, being contiguous to the <lb/>&longs;uperiour &longs;tone, is thereby defended from <lb/>the pre&longs;&longs;ure of the Air which con&longs;equent­<lb/>ly pre&longs;&longs;ing the lower &longs;tone again&longs;t the up-<pb xlink:href="013/01/260.jpg" pagenum="230"/>per, hinders it from falling, as we have <lb/>el&longs;ewhere more fully declar'd. </s> <s>Upon <lb/>the&longs;e grounds we conjectur'd that in ca&longs;e <lb/>we could procure two marbles exactly <lb/>ground to one another; and in ca&longs;e we <lb/>could al&longs;o &longs;ufficiently evacuate our Re­<lb/>ceiver, the lower &longs;tone would, for want <lb/>of the wonted and &longs;u&longs;taining pre&longs;&longs;ure of <lb/>the Air, fall from the upper. </s> <s>But the <lb/>further tryal of this Experiment we mu&longs;t, <lb/>unle&longs;s your Lord&longs;hip think it worth Your <lb/>making at <emph type="italics"/>Paris,<emph.end type="italics"/> put off till a fitter <lb/>opportunity. </s> <s>For where we now are, we <lb/>cannot procure marbles &longs;o exactly ground, <lb/>that they will &longs;u&longs;taine one another in the <lb/>Air, above a minute or two, which is a <lb/>much &longs;horter time than the emptying of <lb/>our Receiver requires. </s> <s>We did indeed <lb/>try to make our marbles &longs;tick clo&longs;e to­<lb/>gether by moi&longs;tening their polli&longs;hed &longs;ur­<lb/>faces with rectifi'd &longs;pirit of Wine, in re­<lb/>gard that Liquor by its &longs;udden avolation <lb/>from marble, if powr'd thereon, without <lb/>leaving it moi&longs;t or le&longs;s &longs;mooth, &longs;eem'd <lb/>unable to &longs;u&longs;taine them together after the <lb/>manner of a glutinous body, and yet <lb/>&longs;eem'd &longs;ufficient to exclude and keep out <lb/>the Air. </s> <s>But this we try'd to little pur­<lb/>po&longs;e, for having convey'd into the Recei-<pb xlink:href="013/01/261.jpg" pagenum="231"/>ver two black &longs;quare marbles (the one of <lb/>two inches and a third in length or <lb/>breadth, and &longs;omewhat more than halfe <lb/>an inch in thickne&longs;s: The other of the &longs;ame <lb/>extent, but not much above halfe &longs;o <lb/>thick) fa&longs;ten'd together by the interven­<lb/>tion of pure Spirit of Wine; and having <lb/>&longs;u&longs;pended the thicker by a &longs;tring from the <lb/>cover, we found not that the ex&longs;uction of <lb/>the ambient Air would &longs;eparate them, <lb/>though a weight amounting to four oun­<lb/>ces were fa&longs;ten'd to the lowermo&longs;t mar­<lb/>ble to facilitate it's falling off. </s></p><p type="margin"> <s><margin.target id="marg38"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 31,</s></p><p type="main"> <s>I would gladly have the Experiment <lb/>try'd with marble &longs;o well polli&longs;h't as to <lb/>need no Liquor what&longs;oever to make them <lb/>cohere, and in a Ve&longs;&longs;el out of which the <lb/>Air may be more perfectly drawn than it <lb/>was out of ours. </s> <s>But in the mean time <lb/>though we will not determin whether the <lb/>Spirit of wine did contribute to the &longs;trong <lb/>cohe&longs;ion of the&longs;e &longs;tones, otherwi&longs;e than <lb/>by keeping ev'n the &longs;ubtl'&longs;t parts of the <lb/>Air from getting in between them, yet it <lb/>&longs;eemed that the not falling downe of the <lb/>lowermo&longs;t marble might without impro­<lb/>bability be a&longs;crib'd to the pre&longs;&longs;ure of the <lb/>Air remaining in the Receiver; which as <lb/>we formerly noted having been able <pb xlink:href="013/01/262.jpg" pagenum="232"/>to keep a Cylinder of water of above <lb/>a Foot in height from falling to the bot­<lb/>tom of the Tube, may well enough be <lb/>&longs;uppo&longs;'d capable of keeping &longs;o broad a flat <lb/>Marble from de&longs;cending. </s> <s>And though this <lb/>may &longs;eem a &longs;trange proof of the &longs;trength of <lb/>the &longs;pring of Air, ev'n when rarified, yet it <lb/>will &longs;carce &longs;eem incredible to him that has <lb/>ob&longs;erv'd how exceeding &longs;trong a cohe&longs;ion <lb/>may be made betwixt broad Bodies, one­<lb/>ly by their immediate touching one ano­<lb/>ther. </s> <s>A notable in&longs;tance of which, I <lb/>have met with in this &longs;hort Narrative of <lb/><arrow.to.target n="marg39"/><lb/>the Learned <emph type="italics"/>Zucchius. </s> <s>Fuveni<emph.end type="italics"/> (&longs;ays he) <lb/><emph type="italics"/>lacertorum &longs;uorum robur: jactanti propo­<lb/>&longs;ita &longs;emel e&longs;t lamina ærea, per an&longs;am in <lb/>medio extantem apprehen&longs;am elevanda è <lb/>tabula marmorea, cui optime congruebat: <lb/>qui primo tanquam rem ludicr am puero <lb/>committendam contemp&longs;it: tum in&longs;tanti­<lb/>bus amicis manum utrámque admovens, <lb/>cum luctatus diu hærentem non removi&longs;&longs;et, <lb/>excu&longs;avit impotentiam, objecta perigrini <lb/>& potenti&longs;simi glutinis interpo&longs;itione, quo <lb/>forti&longs;sime copulante nequiret divelli; do­<lb/>nec vidit ab alio per tabulam facilimè lami­<lb/>nam deduci, & ad extrema product am, & <lb/>actam in tran&longs;ver&longs;um inàe deportari.<emph.end type="italics"/></s><s> But <lb/>that we may learn from our own Engine, <pb xlink:href="013/01/263.jpg" pagenum="233"/>that two Bodies, though they touch each <lb/>other but in a &longs;mall part of their &longs;urfaces, <lb/>may be made to cohere very &longs;trongly, <lb/>onely by this, That the Air pre&longs;&longs;es much <lb/>more forcibly upon the inferior &longs;uperfi­<lb/>cies of the lowermo&longs;t Body, then upon <lb/>the upper &longs;urface of the &longs;ame: We will <lb/>hereunto annex the following Experi­<lb/>ment, though out of the order wherein <lb/>they were made. <lb/><arrow.to.target n="marg40"/></s></p><p type="margin"> <s><margin.target id="marg39"/><emph type="italics"/>P. Nic. <lb/></s> <s>Zucchius <lb/>opal Schot: <lb/>part<emph.end type="italics"/> 1. <lb/><gap/></s></p><p type="margin"> <s><margin.target id="marg40"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 32.</s></p><p type="main"> <s>I remember I have, in a Di&longs;cour&longs;e con­<lb/>cerning Fluidity and Firmne&longs;s, made <lb/>mention of my having, by the ex&longs;uction <lb/>of the Air out of a Gla&longs;s Ve&longs;&longs;el, made <lb/>that Ve&longs;&longs;el take up, or &longs;uck up (to &longs;peak in <lb/>the common Language) a Body weighing <lb/>divers Ounces; but our Engine affording <lb/>us the opportunity of making con&longs;ider­<lb/>abler Experiments of that kinde, We <lb/>thought fit to make a further tryal of the <lb/>force of the Atmo&longs;phere's pre&longs;&longs;ure up­<lb/>wards, after the following manner. </s></p><p type="main"> <s>The Receiver having been exqui&longs;itely <lb/>clo&longs;'d, as we have often taught already, <lb/>and the Air being in a good mea&longs;ure drawn <lb/>out of it, it was remov'd from off the <lb/>Pump: and to the lower Branch of the <pb xlink:href="013/01/264.jpg" pagenum="234"/>Stop-cock, there was &longs;peedily apply'd a <lb/>tapering Valve of bra&longs;s, &longs;uch as is de&longs;crib'd <lb/>in the 9<emph type="sup"/>th<emph.end type="sup"/> fig: made fit to go with its nar­<lb/>rower end into the cavity of the branch, <lb/>and to fill the orifice of that cavity with <lb/>its broader part. </s> <s>And that the Air might <lb/>not get in at the litle intervals, left here <lb/>and there between the convex &longs;urface of <lb/>the &longs;topple and the internall edge of the <lb/>branch, tho&longs;e intervals were &longs;top't with <lb/>a little Diachylon. </s> <s>And to the doore, <lb/>or, (if you plea&longs;e) that part of the Valve <lb/>which was to move to and fro, and in <lb/>this Experiment hung perpendicular to <lb/>the Horizon, there was, at a button of <lb/>bra&longs;s belonging to the Valve fa&longs;ten'd a <lb/>broad &longs;cale wherein weights were to be <lb/>put. </s> <s>This done the key of the Stop-cock <lb/>was turn'd, and the externall Air beating <lb/>like a forcible &longs;treame upon the Valve <lb/>to get in there, it did &longs;uddenly both &longs;hut <lb/>the Valve and keep it &longs;hut &longs;o &longs;trongly, <lb/>that we had time to ca&longs;t in diver&longs;e weights <lb/>one after another into the Scale; till at <lb/>length the weight overpowering the pre&longs;­<lb/>&longs;ure of the Atmo&longs;phere, drew downe the <lb/>Valve by the &longs;tringes that ty'd the Scale <lb/>to it, and gave liberty to the outward Air <lb/>to ru&longs;h into the Receiver. </s> <s>Though a-<pb xlink:href="013/01/265.jpg" pagenum="235"/>nother time, when the Valve had but lit­<lb/>tle weight hanging at it, being, by I know <lb/>not what accident, drawn down beneath its <lb/>former place, it was by the impetuous <lb/>current of the outward Air &longs;uddenly im­<lb/>pell'd up into it again, and kept there. <lb/></s> <s>But in the former Experiment it is re­<lb/>markable, That though the Receiver were <lb/>not well exhau&longs;ted, and though it leak'd <lb/>whil'&longs;t the re&longs;t of the Experiment was in <lb/>pro&longs;ecution, and though the Valve <lb/>whereon the Cylinder of the Atmo&longs;phere <lb/>could pre&longs;s, were not above an Inch and <lb/>a half in Diameter, yet the weight kept <lb/>up by &longs;uction, or rather &longs;upported by the <lb/>Air, namely the Valve, the Seal and <lb/>what was ca&longs;t into it, being &longs;ent to be <lb/>weigh'd, amounted to about ten of our <lb/>common Pounds, con&longs;i&longs;ting of &longs;ixteen <lb/>Ounces apiece: So that we doubted not <lb/>but that, had the Experiment been made <lb/>with favorable Circum&longs;tances, the Air <lb/>endeavoring to pre&longs;s in at the Orifice of <lb/>the Stop-cock, would have kept a very <lb/>much greater weight from falling out of <lb/>it; I &longs;ay the Air, becau&longs;e we found, by <lb/>tryal purpo&longs;ely made, that neither the <lb/>imperfect contact of the Valve and the <lb/>Stop-cock, nor the Diachylon that was <pb xlink:href="013/01/266.jpg" pagenum="236"/>employ'd to fill up the little Crannies left <lb/>betwixt them, were con&longs;iderable in this <lb/>Experiment; by which may among other <lb/>things appear, that I did not without <lb/>cau&longs;e in the above-nam'd Di&longs;cour&longs;e touch­<lb/>ing Fluidity and Firmne&longs;s, a&longs;cribe a great <lb/>force, ev'n to &longs;uch Pillars of Air as may <lb/>be &longs;uppo&longs;'d to begin at the top of the <lb/>Atmo&longs;phere, and recoyling from the <lb/>ground to terminate on the Bodies on <lb/>which they pre&longs;s: &longs;ince in the pre&longs;ent Ex­<lb/>periment &longs;uch a weight was &longs;upported by <lb/>&longs;o &longs;lender a Cylinder of Air, rebounding <lb/>from the Earth to the Valve whereon it <lb/>did bear. </s></p><p type="main"> <s>BUt in regard we have not yet been <lb/><arrow.to.target n="marg41"/><lb/>able to empty &longs;o great a Ve&longs;&longs;el as our <lb/>Receiver, &longs;o well as we can the Cylinder <lb/>it &longs;elf; our Pump alone may afford us a <lb/>nobler in&longs;tance of the fotce of the Air we <lb/>live in, in&longs;omuch, that by help of this <lb/>part of our Engine, we may give a pretty <lb/>near ghe&longs;s at the &longs;trength of the Atmo­<lb/>&longs;phere, computed as a weight. </s> <s>And the <lb/>way may be this; Fir&longs;t, the Sucker be­<lb/>ing brought to move ea&longs;ily up and down <lb/>the Cylinder, is to be impell'd to the top <pb xlink:href="013/01/267.jpg" pagenum="237"/>of it: Then the Receiver mu&longs;t be taken <lb/>off from the Pump, that the upper Ori­<lb/>fice of the Cylinder remaining open, the <lb/>Air may freely &longs;ucceed the Sucker, and <lb/>therefore readily yield to its motion <lb/>downward. </s> <s>This done, there mu&longs;t be <lb/>fa&longs;ten'd to one of the Iron Teeth of the <lb/>Sucker, &longs;uch a weight as may ju&longs;t &longs;uffice <lb/>to draw it to the bottom of the Cylinder. <lb/></s> <s>And having thus examin'd what weight is <lb/>nece&longs;&longs;ary to draw down the Sucker, when <lb/>the Atmo&longs;phere makes no other then the <lb/>ordinary re&longs;i&longs;tance of the Air again&longs;t its <lb/>de&longs;cent; the Sucker mu&longs;t be again forc'd <lb/>to the top of the Cylinder, who&longs;e upper <lb/>Orifice mu&longs;t now be exactly clo&longs;ed; and <lb/>then (the fir&longs;t weight remaining) we ea&longs;i­<lb/>ly may, by hanging a Scale to the above­<lb/>mention'd Iron (that makes part of the <lb/>Sucker) ca&longs;t in known weights &longs;o long, <lb/>till in &longs;pight of the reluctancy of the At­<lb/>mo&longs;phere the Sucker be drawn down. </s> <s>For <lb/>to the&longs;e weights in the Scale, that of the <lb/>Scale it &longs;elf being added, the &longs;um will give <lb/>us the weight of a Column of Air, equal <lb/>in Diameter to the Sucker, or to the ca­<lb/>vity of the Cylinder; and in length to <lb/>the heighth of the Atmo&longs;phere. </s></p><p type="margin"> <s><margin.target id="marg41"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 33.</s></p><p type="main"> <s>According to this method we did, &longs;ince <pb xlink:href="013/01/268.jpg" pagenum="238"/>the writing of the la&longs;t Experiment, at­<lb/>tempt to mea&longs;ure the pre&longs;&longs;ure of the At­<lb/>mo&longs;phere, but found it more difficult then <lb/>we expected, to perform it with any ac­<lb/>curatene&longs;s; for though by the help of the <lb/><emph type="italics"/>Manubrium<emph.end type="italics"/> the Sucker moved up and <lb/>down with &longs;o much ea&longs;e, that one would <lb/>have thought that both its convex &longs;urface, <lb/>and the concave one of the Cylinder were <lb/>exqui&longs;itely &longs;mooth, & as it were &longs;lippery; <lb/>yet when the Sucker came to be moved <lb/>onely with a dead weight or pre&longs;&longs;ure (that <lb/>was not (like the force of him that <lb/>pump'd) intended as occa&longs;ion required) <lb/>we found that the little rufne&longs;&longs;es, or other <lb/>inequalities, and perhaps too, the unequal <lb/>pre&longs;&longs;ure of the Leather again&longs;t the cavity <lb/>of the Cylinder, were able now and then <lb/>to put a &longs;top to the de&longs;cent or a&longs;cent of <lb/>the Sucker, though a very little external <lb/>help would ea&longs;ily &longs;urmount that impedi­<lb/>ment; and then the Sucker would, for a <lb/>while, continue its formerly interrupted <lb/>motion, though that a&longs;&longs;i&longs;tance were with­<lb/>drawn. </s> <s>But this di&longs;couragement did not <lb/>deterre us from pro&longs;ecuting our Experi­<lb/>ment, and endeavoring, by a careful trial, <lb/>to make it as in&longs;tructive as we could. <lb/></s> <s>We found then that a Leaden Weight, <pb xlink:href="013/01/269.jpg" pagenum="239"/>of 28 pounds (each con&longs;i&longs;ting of &longs;ixteen <lb/>Ounces) being fa&longs;tned to one of the teeth <lb/>of the Sucker, drew it down &longs;lowly e­<lb/>nough; when the upper Orifice of the <lb/>Cylinder was left open, though by the <lb/>help of Oyl and Water, and by the fre­<lb/>quent moving the Sucker up and down <lb/>with the <emph type="italics"/>Manubrium,<emph.end type="italics"/> its motion in the <lb/>Cylinder had been before purpo&longs;ely faci­<lb/>litated. </s> <s>This done, the upper Orifice of <lb/>the Cylinder was very carefully and clo&longs;e­<lb/>ly &longs;topp'd, the Valve being likewi&longs;e &longs;hut <lb/>with its wonted Stopple well oyl'd, af­<lb/>ter the Sucker had been again impell'd <lb/>up to the top of the Cylinder. </s> <s>Then to <lb/>the precedent twenty eight pound, we <lb/>added a hundred and twelve pounds more, <lb/>which forcing down the Sucker, though <lb/>but lei&longs;urely, we took off the twenty <lb/>eight pound weight; and being unable to <lb/>procure ju&longs;t &longs;uch weights as we would <lb/>have had, we hung on, in&longs;tead of it, one <lb/>of fourteen pound, but found that, with <lb/>the re&longs;t, unable to carry down the Sucker. <lb/></s> <s>And to &longs;atisfie our &longs;elves, and the Spe­<lb/>ctators, that it was the re&longs;i&longs;tance of the <lb/>ambient Air that hinder'd the de&longs;cent of <lb/>&longs;o great a weight, after that we had try'd <lb/>that upon un&longs;topping the Valve, and <pb xlink:href="013/01/270.jpg" pagenum="240"/>thereby opening an acce&longs;s to the external <lb/>Air, the Sucker would be immediately <lb/>drawn down: After this, I &longs;ay, we made <lb/>this further Experiment, That having by <lb/>a Man's &longs;trength forcibly depre&longs;&longs;'d the <lb/>Sucker to the bottom of the Cylinder, <lb/>and then fa&longs;tned weights to the above­<lb/>named Iron that makes part of that Suc­<lb/>ker, the pre&longs;&longs;ure of the external Air find­<lb/>ing little or nothing in the cavity of the <lb/>evacuated Cylinder to re&longs;i&longs;t it, did pre­<lb/>&longs;ently begin to impell the Sucker, with <lb/>the weights that clogg'd it, towards the <lb/>upper part of the Cylinder, till &longs;ome <lb/>&longs;uch accidental Impediment as we former­<lb/>ly mention'd, check'd its cour&longs;e; and <lb/>when that rub, which ea&longs;ily might be, was <lb/>taken out of the way, it would continue <lb/>its a&longs;cent to the top, to the no &longs;mall won­<lb/>der of tho&longs;e By &longs;tanders, that could not <lb/>comprehend how &longs;uch a weight could a&longs;­<lb/>cend, as it were, of it &longs;elf; that is, with­<lb/>out any vi&longs;ible force, or &longs;o much as Su­<lb/>ction to lift it up. </s> <s>And indeed it is very <lb/>con&longs;iderable, that though po&longs;&longs;ibly there <lb/>might remain &longs;ome particles of Air in the <lb/>Cylinder, after the drawing down of the <lb/>Sucker; yet the pre&longs;&longs;ure of a Cylinder of <lb/>the Atmo&longs;phere, &longs;omewhat le&longs;s then <pb xlink:href="013/01/271.jpg" pagenum="241"/>three Inches in Diameter (for, as it was <lb/>&longs;aid in the de&longs;cription of our Engine, the <lb/>cavity of the Cylinder was no broader) <lb/>was able, uncompre&longs;&longs;'d, not only to &longs;u&longs;tain, <lb/>but even to drive up a weight of an hun­<lb/>dred and odde pounds: for be&longs;ides the <lb/>weight of the whole Sucker it &longs;elf, which <lb/>amounts to &longs;ome pounds, the weights an­<lb/>nexed to it made up a hundred and three <lb/>pounds, be&longs;ides an Iron Bar, that by con­<lb/>jecture weighed two pounds more; and <lb/>yet all the&longs;e together fall &longs;omewhat &longs;hort <lb/>of the weight which we lately mention'd, <lb/>the re&longs;i&longs;tance of the Air to have held &longs;u­<lb/>&longs;pended in the cavity of the Cylinder. </s></p><p type="main"> <s>And though (as hath been already ac­<lb/>knowledg'd) we cannot, peradventure, <lb/>obtain by the recited means &longs;o exact an <lb/>account as were to be wi&longs;h'd, of what we <lb/>would di&longs;cover: Yet, if it &longs;erve us to <lb/>ground Conjectures more approaching to <lb/>the Truth, then we have hitherto met <lb/>with, I hope it will be con&longs;ider'd (which <lb/>a famous Poet judiciou&longs;ly &longs;ays) </s></p><p type="main"> <s><emph type="center"/><emph type="italics"/>E&longs;t quoddam prodire tenus, &longs;i non da­<lb/>tur ultra.<emph.end type="italics"/><emph.end type="center"/></s></p><p type="main"> <s>Peradventure it will not be imperti-<pb xlink:href="013/01/272.jpg" pagenum="242"/>nent to annex to the other Circum&longs;tances <lb/>that have been already &longs;ee down concern­<lb/>ing this Experiment, That it was made in <lb/>Winter, in Weather neither Fro&longs;ty nor <lb/>Rainy, about the change of the Moon, <lb/>and at a place who&longs;e latitude is near about <lb/>51<emph type="sup"/>d<emph.end type="sup"/> and a half: For perhaps the force or <lb/>pre&longs;&longs;ure of the Air may vary, according <lb/>to the Sea&longs;ons of the Year, the tempera­<lb/>ture of the Weather, the elevation of the <lb/>Pole, or the pha&longs;es of the Moon; all, or <lb/>even any of them &longs;eeming capable to al­<lb/>ter either the heighth or con&longs;i&longs;tence of the <lb/>incumbent Atmo&longs;phere: And therefore <lb/>it would not be ami&longs;s if this Experiment <lb/>were carefully tryd at &longs;everal times and <lb/>places, with variety of Circum&longs;tances. </s> <s>It <lb/>might al&longs;o be try'd with Cylinders of &longs;e­<lb/>veral Diameters, exqui&longs;itely fitted with <lb/>Suckers, that we might know what pro­<lb/>portion &longs;everal Pillars of the Atmo&longs;phere <lb/>bear, to the Weights they are able to &longs;u­<lb/>&longs;tain or lift up; and con&longs;equently, whe­<lb/>ther the increa&longs;e or decrement of the re­<lb/>&longs;i&longs;tance of the ambient Air, can be re­<lb/>duc'd to any regular proportion to the <lb/>Diameters of the Suckers: The&longs;e, and <lb/>divers other &longs;uch things which may be <lb/>try'd with this Cylinder, might mo&longs;t of <pb xlink:href="013/01/273.jpg" pagenum="243"/>them bemore exactly try'd by the Tori­<lb/>cellian Experiment, if we could get Tubes <lb/>&longs;o accurately blown and drawn, that the <lb/>Cavity were perfectly Cylindrical. </s></p><p type="main"> <s>To dwell upon all the &longs;everal Refle­<lb/>ctions, that a &longs;peculative Wit might <lb/>make upon this and the foregoing Expe­<lb/>riment: (I mean the thirty third and thir­<lb/>ty &longs;econd, would require almo&longs;t a Vo­<lb/>lume, whereas our occa&longs;ions will &longs;carce <lb/>allow us time to touch upon three or <lb/>four of the chief Inferences that &longs;eem de­<lb/>ducible from them, and therefore we &longs;hall <lb/>content our &longs;elves to point at tho&longs;e <lb/>few. </s></p><p type="main"> <s>And fir&longs;t, as many other <emph type="italics"/>Phænomena<emph.end type="italics"/><lb/>of our Engine, &longs;o e&longs;pecially, the two <lb/>lately mention'd Experiments, &longs;eem ve­<lb/>ry much to call in que&longs;tion the receiv'd <lb/>Opinion of the Nature or Cau&longs;e of Su­<lb/>ction. </s> <s>For 'tis true indeed, that when men <lb/>&longs;uck, they commonly u&longs;e &longs;ome manife&longs;t <lb/>endeavour by a peculiar motion of their <lb/>Mouthes, Che&longs;ts, and &longs;ome other con&longs;pi­<lb/>ring parts, to convey to them the body <lb/>to be &longs;uckt in. </s> <s>And hence perhaps they <lb/>have taken occa&longs;ion, to think that in all <pb xlink:href="013/01/274.jpg" pagenum="244"/>Suction there mu&longs;t be &longs;ome Endeavour <lb/>or motion in the &longs;ucking to attract the <lb/>&longs;ucked Body. </s> <s>But in our la&longs;t Experi­<lb/>ment it appeares not at all how the up­<lb/>per part of the empty'd Cylinder that re­<lb/>maines movele&longs;s all the while, or any <lb/>part of it, does at all endeavour to draw <lb/>to it the depre&longs;&longs;ed Sucker and the an­<lb/>nex'd weights. </s> <s>And yet tho&longs;e that be­<lb/>hold the a&longs;cention of the Sucker, without <lb/>&longs;eriou&longs;ly con&longs;idering the cau&longs;e of it, doe <lb/>readily conclude it to be ray&longs;'d by &longs;ome­<lb/>thing that powerfully Sucks or attracts <lb/>it, though they &longs;ee not what that may <lb/>be or where it lurks. </s> <s>So that it &longs;eemes <lb/>not ab&longs;olutely nece&longs;&longs;ary to Suction, that <lb/>there be in the Body, which is &longs;aid to &longs;uck, <lb/>an endeavor or motion in order thereun­<lb/>to, but rather that Suction may be at lea&longs;t <lb/>for the mo&longs;t part reduc'd to Pul&longs;ion, and <lb/>its effects a&longs;crib'd to &longs;uch a pre&longs;&longs;ure of <lb/>the neighboring air upon tho&longs;e Bodies <lb/>(whther aërial, or of other Natures) that <lb/>are contiguous to the Body that is &longs;ayd to <lb/>attract them, as is &longs;tronger than that Sub­<lb/>&longs;tance which po&longs;&longs;e&longs;&longs;es the cavity of that <lb/>&longs;ucking Body is able to re&longs;i&longs;t. </s> <s>To ob­<lb/>ject here, that it was &longs;ome particles of <lb/>Air remaining in the empty'd Cylin-<pb xlink:href="013/01/275.jpg" pagenum="245"/>der that attracted this weight to obviate <lb/>a <emph type="italics"/>Vacuum,<emph.end type="italics"/> will &longs;carce be &longs;atisfactory; un­<lb/>le&longs;s it can be cleerly made out by what li­<lb/>tle hooks, or other grappling In&longs;truments, <lb/>the internal Air could take hold of the <lb/>Sucker; how &longs;o litle of it obtain'd the <lb/>force to lift up &longs;o great a weight; and why <lb/>al&longs;o, upon the letting in of a litle more <lb/>Air into one of our evacuated Ve&longs;­<lb/>&longs;els, the attraction is, in&longs;tead of being <lb/>&longs;trengthen'd, much weaken'd, though, <lb/>if there were danger of a <emph type="italics"/>Vacuum<emph.end type="italics"/> be­<lb/>fore, it would remain, notwith&longs;tanding <lb/>this ingre&longs;s of a little Air. </s> <s>For that &longs;till <lb/>there remain'd in the capacity of the ex­<lb/>hau&longs;ted Cylinder &longs;tore of little rooms, <lb/>or &longs;paces empty or devoid of Air, may <lb/>appear by the great violence wherewith <lb/>the air ru&longs;hes in, if any way be open'd to it. <lb/></s> <s>And that 'tis not &longs;o much the decrement <lb/>of the <emph type="italics"/>Vacuum<emph.end type="italics"/> within the cavity of the <lb/>ve&longs;&longs;el that debilitates the attraction, as the <lb/>&longs;pring of the included air (who&longs;e pre&longs;ence <lb/>makes the decrement) that does it by <lb/>re&longs;i&longs;ting the pre&longs;&longs;ure of the external Air, <lb/>&longs;eems probable, partly from the Di&longs;abi­<lb/>lity of vacuities, whether greater or le&longs;&longs;er, <lb/>to re&longs;i&longs;t the pre&longs;&longs;ure of the Air; and part­<lb/>ly by &longs;ome of the <emph type="italics"/>Phænomena<emph.end type="italics"/> of our Ex-<pb xlink:href="013/01/276.jpg" pagenum="246"/>periments, and particularly by this Cir­<lb/>cum&longs;tance of the three and Thirtieth, <lb/>that the Sucker was by the pre&longs;&longs;ure of the <lb/>Ambient Air impell'd upwards, with its <lb/>weight hanging at it, not only when it <lb/>was at the bottome of the Cylinder, and <lb/>con&longs;equently left a great <emph type="italics"/>Vacuum<emph.end type="italics"/> in the <lb/>cavity of it; but when the Sucker had <lb/>been already impel'd almo&longs;t to the top of <lb/>the Cylinder, and con&longs;equently, when the <lb/><emph type="italics"/>Vacuum<emph.end type="italics"/> that remain'd was become very <lb/>litle in compari&longs;on of that which preceded <lb/>the beginning of the Sucker's a&longs;cention. </s></p><p type="main"> <s>In the next place, the&longs;e Experiments <lb/>may teach us, what to judge of the vul­<lb/>gar Axiom receiv'd for &longs;o many Ages <lb/>as an undoubted Truth in the Peripate­<lb/>tick Schools; That Nature abhorres <lb/>and flys a <emph type="italics"/>Vacuum,<emph.end type="italics"/> and that to &longs;uch a de­<lb/>gree, that no humane power (to go no <lb/>higher) is able to make one in the Uni­<lb/>ver&longs;e; wherein Heaven and Earth would <lb/>change places, and all its other Bodyes <lb/>rather act contrary to their own Nature, <lb/>than &longs;uffer it. </s> <s>For, if by a <emph type="italics"/>Vacuum<emph.end type="italics"/> we <lb/>will under&longs;tand a place perfectly devoid <lb/>of all corporeal Sub&longs;tance, it may be in­<lb/>deed then, as we formerly noted be plau­<lb/>&longs;ibly enough maintain'd, that there is <pb xlink:href="013/01/277.jpg" pagenum="247"/>no &longs;uch thing in the world; but that the <lb/>generality of the Pleni&longs;ts, (e&longs;pecially till <lb/>of late yeares &longs;ome of them grew more <lb/>wary) did not take a <emph type="italics"/>Vacuum<emph.end type="italics"/> in &longs;o &longs;trict <lb/>a Sen&longs;e, may appear by the Experiments <lb/>formerly, and ev'n to this Day imploy'd <lb/>by the Deniers of a Vacuum, to prove it <lb/>impo&longs;&longs;ible that there can be any made. <lb/></s> <s>For when they alleadge (for In&longs;tance) <lb/>that when a man &longs;ucks Water through a <lb/>long Pipe, that heavy Liquor, contrary <lb/>to its Nature, a&longs;cends into the Sucker's <lb/>mouth, only, to fill up that room made <lb/>by the Dilatation of his Bre&longs;t and <lb/>Lungs, which otherwi&longs;e will in part be <lb/>empty. </s> <s>And when they tell us, that the <lb/>rea&longs;on why if a long Pipe exactly <lb/>clos'd at one end be fill'd top-ful <lb/>of Water, and then inverted, no Liquor <lb/>will fall out of the open Orifice; Or, to <lb/>u&longs;e a more familiar Example, when they <lb/>teach, that the cau&longs;e why in a Gardiner's <lb/>watering Pot &longs;hap'd conically, or like a <lb/>Sugar-Loaf fill'd with Water, no Liquor <lb/>fals down through the numerous holes <lb/>at the bottome, whil&longs;t the Gardiner keeps <lb/>his Thumb upon the Orifice of the litle <lb/>hole at the top, and no longer, mu&longs;t be <lb/>that it in the ca&longs;e propo&longs;ed the Water <pb xlink:href="013/01/278.jpg" pagenum="248"/>&longs;hould de&longs;cend, the Air being unable to <lb/>&longs;ucceed it, there would be left at the up­<lb/>per and de&longs;erted part of the Ve&longs;&longs;el a <emph type="italics"/>Va­<lb/>cuum,<emph.end type="italics"/> that would be avoided if the hole <lb/>at the top were open'd. </s> <s>When (I &longs;ay) <lb/>they alleadge &longs;uch Experiments, the <lb/>Tendency of them &longs;eems plainly to im­<lb/>port, that they mean, by a <emph type="italics"/>Vacuum,<emph.end type="italics"/> any <lb/>&longs;pace here below that is not fill'd with a <lb/>vi&longs;ible body, or at lea&longs;t with Air; though <lb/>it be not quite devoy'd of all Body what­<lb/>&longs;oever. </s> <s>For why &longs;hould Nature, out of <lb/>her dete&longs;tation of a <emph type="italics"/>Vacuum,<emph.end type="italics"/> make Bo­<lb/>dies act contrary to their own Tendency, <lb/>that a place may be fill'd with Air, if its <lb/>being &longs;o were not nece&longs;&longs;ary to the avoi­<lb/>ding of a <emph type="italics"/>Vacuum.<emph.end type="italics"/></s></p><p type="main"> <s>Taking then a <emph type="italics"/>Vacuum<emph.end type="italics"/> in this vulgar <lb/>and obvious &longs;ence, the common opinion <lb/>about it &longs;eems lyable to &longs;everal Exce­<lb/>ptions, whereof &longs;ome of the chief are <lb/>&longs;ugge&longs;ted to us by our Engine. </s></p><p type="main"> <s>It will not ea&longs;ily then be intelligibly <lb/>made out, how hatred or aver&longs;ation, <lb/>which is a pa&longs;&longs;ion of the Soule, can either <lb/>for a <emph type="italics"/>Vacuum,<emph.end type="italics"/> or any other object, be &longs;up­<lb/>pos'd to be in Water, or &longs;uch like inani­<lb/>mate Body, which cannot be pre&longs;um'd <lb/>to know when a <emph type="italics"/>Vacuum<emph.end type="italics"/> would en&longs;ue; if <pb xlink:href="013/01/279.jpg" pagenum="249"/>they did not be&longs;tirre them&longs;elves to pre­<lb/>vent it, nor to be &longs;o generous as to act <lb/>contrary to what is mo&longs;t conducive to <lb/>their own particular pre&longs;ervation for the <lb/>publique good of the Univer&longs;e. </s> <s>As much <lb/>then of intelligible and probable Truth, <lb/>as is contain'd in this Metaphoricall Ex­<lb/>pre&longs;&longs;ion, &longs;eems to amount but to this; <lb/>That by the Wi&longs;e Author of Nature <lb/>(who is ju&longs;tly &longs;ayd to have made all <lb/>things in number, weight, and mea&longs;ure,) <lb/>the Univer&longs;e, and the parts of it, are &longs;o <lb/>contriv'd, that it is as hard to make a <emph type="italics"/>Va­<lb/>cuum<emph.end type="italics"/> in it, as if they &longs;tudiou&longs;ly con&longs;pir'd <lb/>to prevent it. </s> <s>And how far this it &longs;elfe <lb/>may be granted, de&longs;erves to be further <lb/>con&longs;ider'd. </s></p><p type="main"> <s>For in the next place, our Experiments <lb/>&longs;eem to teach, that the &longs;uppo&longs;ed Aver&longs;a­<lb/>tion of Nature to a <emph type="italics"/>Vacuum<emph.end type="italics"/> is but acci­<lb/>dental, or in con&longs;equence partly of the <lb/>Weight and Fluidity, or, at lea&longs;t, Fluxi­<lb/>lity of the Bodies here below; and partly, <lb/>and perhaps principally, of the Spring of <lb/>the air, who&longs;e re&longs;tle&longs;s endeavor to expand <lb/>it &longs;elfe every way, makes it either ruth <lb/>in it &longs;elfe, or compel the interpos'd bo­<lb/>dys into all &longs;paces, where it finds no grea­<lb/>ter re&longs;i&longs;tance than it can &longs;urmount. </s> <s>And <pb xlink:href="013/01/280.jpg" pagenum="250"/>that in tho&longs;e motions which are made <emph type="italics"/>ob­<lb/>fugamVacui<emph.end type="italics"/> (as the common phra&longs;e is) Bo­<lb/>dys act without &longs;uch genero&longs;ity & Con­<lb/>&longs;ideration, as is wont to be a&longs;crib'd to <lb/>them, is apparent enough in our 32<emph type="sup"/>d<emph.end type="sup"/> Ex­<lb/>periment, where the torrent of Air, that <lb/>&longs;eem'd to &longs;trive to get into the Empty'd <lb/>Receiver, did plainly prevent its own <lb/>De&longs;igne, by &longs;o impelling the Value, as <lb/>to make it &longs;hut the only Orifice the Air <lb/>was to get in at. </s> <s>And if afterwards ei­<lb/>ther Nature, or the internal Air, had a de­<lb/>&longs;igne the external Air &longs;hould be attra­<lb/>cted, they &longs;eem'd to pro&longs;ecute very un­<lb/>wi&longs;ely by continuing to &longs;uck the Valve <lb/>&longs;o &longs;trongly, when they found that by <lb/>that Sucction the Valve it &longs;elfe could not <lb/>be drawn in: Whereas by forbearing to <lb/>&longs;uck, the Valve would by it's own weight <lb/>have fall'n down, and &longs;uffer'd the exclu­<lb/>ded Air to returne freely, and to fill <lb/>again the exhau&longs;ted Ve&longs;&longs;el. </s></p><p type="main"> <s>And this minds me to take notice of <lb/>another deficiency, pointed at by our Ex­<lb/>periments in the common Doctrine of <lb/>tho&longs;e Pleni&longs;ts we rea&longs;on with; for many <lb/>of tho&longs;e unu&longs;ual motions in Bodies, that <lb/>are &longs;ayd to be made to e&longs;cape a <emph type="italics"/>Vacuum,<emph.end type="italics"/><lb/>&longs;eem rather made to fill it. </s> <s>For why, <pb xlink:href="013/01/281.jpg" pagenum="251"/>to in&longs;tance in our newly mention'd Ex­<lb/>periment, a&longs;&longs;oon as the Valve was de­<lb/>pre&longs;s'd by the weight we hung at it, <lb/>&longs;hould the Air &longs;o impetuou&longs;ly and copi­<lb/>ou&longs;ly ru&longs;h into the cavity of the Receiver; <lb/>if there were before no vacant room there <lb/>to receive it? </s> <s>and if there were, then all the <lb/>while the Valve kept out the Air, tho&longs;e <lb/>litle &longs;paces in the Receiver, which the <lb/>corpu&longs;cles of that Air afterwards fill'd, <lb/>may be concluded to have remain'd em­<lb/>pty. </s> <s>So that the &longs;eeming violence, <lb/>imploy'd by Nature on the occa&longs;ion of <lb/>the evacuating of the Ve&longs;&longs;el, &longs;eems to <lb/>have come too late to hinder the making <lb/>of Vacuities in the Receiver, and only <lb/>to have, a&longs;&longs;oon as we permitted, fill'd <lb/>up with Air tho&longs;e that were already <lb/>made. </s></p><p type="main"> <s>And as for the Care of the Publique <lb/>Good of the Univer&longs;e a&longs;crib'd to dead <lb/>and &longs;tupid Bodies, wee &longs;hall only de­<lb/>mand, why in our 19<emph type="sup"/>th<emph.end type="sup"/> Experiment, upon <lb/>the Ex&longs;uction of the ambient Air, the <lb/>Water de&longs;erted the upper half of the <lb/>Gla&longs;s-Tube; and did not a&longs;cend to fill <lb/>it up, till the external Air was let in upon <lb/>it: whereas by its ea&longs;y and &longs;udden regai­<lb/>ning that upper part of the Tube, it <pb xlink:href="013/01/282.jpg" pagenum="252"/>appear'd both that there was there much <lb/>&longs;pace devoid of Air, and that the Water <lb/>might with &longs;mall or no re&longs;i&longs;tance have <lb/>a&longs;cended into it, if it could have done &longs;o <lb/>without the impul&longs;ion of the readmitted <lb/>Air; which, it &longs;eems, was nece&longs;&longs;ary to <lb/>mind the Water of its formerly neglected <lb/>Duty to the Univer&longs;e. </s></p><p type="main"> <s>Nay, for ought appeares, ev'n when <lb/>the excluded Air, a&longs;&longs;oon as 'twas per­<lb/>mitted, ru&longs;ht violently into our exhau­<lb/>&longs;ted Receiver, that flowing in of the <lb/>Air proceeded rather from the deter­<lb/>minate Force of the Spring of the <lb/>neighbouring Air, then from any endea­<lb/>vour to fill up, much le&longs;s to prevent va­<lb/>cuity's. </s> <s>For though when as much Air as <lb/>will, is gotten into our Receiver our pre­<lb/>&longs;ent Opponents take it for granted that <lb/>it is full of Air; yet if it be remembred <lb/>that when we made our 17<emph type="sup"/>th<emph.end type="sup"/> Experiment <lb/>we crouded in more Air to our Receiver <lb/>than it u&longs;ually holds; and if we al&longs;o con­<lb/>&longs;ider (which is much more) the Air of <lb/>the &longs;ame con&longs;i&longs;tence with that in our <lb/>Receiver may in wind guns, as is known, <lb/>and as we have try'd, be compre&longs;&longs;ed at <lb/>lea&longs;t into halfe its wonted room (I &longs;ay at <lb/>lea&longs;t, becau&longs;e &longs;ome affirme, that the Air <pb xlink:href="013/01/283.jpg" pagenum="253"/>may be thru&longs;t into an 8<emph type="sup"/>th<emph.end type="sup"/>, or a yet &longs;maller <lb/>part of its ordinary extent) it &longs;eems ne­<lb/>ce&longs;&longs;ary to admit either a notion of conden­<lb/>&longs;ation & rarefaction that is not intelligi­<lb/>ble, or that in the capacity of our Recei­<lb/>ver when pre&longs;um'd to be full of Air, there <lb/>yet remain'd as much of &longs;pace as was ta­<lb/>ken up by all the aërial corpu&longs;cles unpo&longs;­<lb/>&longs;e&longs;&longs;ed by the Air. </s> <s>Which &longs;eemes plainly, <lb/>to infer that the Air that ru&longs;h'd into our <lb/>empty'd ve&longs;&longs;el did not doe it preci&longs;ely <lb/>to fill up the Vacuities of it, &longs;ince it left &longs;o <lb/>many unfill'd, but rather was thru&longs;t in by <lb/>the pre&longs;&longs;ure of the contiguous Air; which <lb/>as it could not, but be always ready to ex­<lb/>pand it &longs;elfe, where it found lea&longs;t re&longs;i­<lb/>&longs;tance, &longs;o was it unable to fill the Recei­<lb/>ver any more, then until the Air within <lb/>was reduc'd to the &longs;ame mea&longs;ure of Com­<lb/>pactne&longs;s with that without. </s></p><p type="main"> <s>We may al&longs;o from our two already of­<lb/>ten mention'd Experiments further de­<lb/>duce, that, (&longs;ince Natures hatred of a <lb/><emph type="italics"/>Vacuum<emph.end type="italics"/> is but Metaphorical and Ac­<lb/>cidental, being but a con&longs;equence or re­<lb/>&longs;ult of the pre&longs;&longs;ure of the Air and of the <lb/>Gravity, and partly al&longs;o of the Fluxility <lb/>of &longs;ome other bodies) The power &longs;hee <lb/>makes u&longs;e of to hinder a Vacuum, is not <pb xlink:href="013/01/284.jpg" pagenum="254"/>(as we have el&longs;e-where al&longs;o noted) any <lb/>&longs;uch boundle&longs;s thing as men have been <lb/>pleas'd to imagine. </s> <s>And the rea&longs;on, why <lb/>in the former Experiments, mentioned <lb/>in favour of the Pleni&longs;ts, Bodies &longs;eem to <lb/>forget their own Natures to &longs;hun a <emph type="italics"/>Va­<lb/>cuum,<emph.end type="italics"/> &longs;eems to be but this; That in the <lb/>alleadged ca&longs;es the weight of that Wa­<lb/>ter that was either kept from falling or <lb/>impell'd up, was not great enough to <lb/>&longs;urmount the pre&longs;&longs;ure of the contiguous <lb/>Air; which, if it had been, the Water <lb/>would have &longs;ub&longs;ided, though no Air could <lb/>have &longs;ucceeded. </s> <s>For not to repeat that <lb/>Experiment of Mon&longs;ieur <emph type="italics"/>Pa&longs;chal<emph.end type="italics"/> (for­<lb/>merly mention'd to have been try'd in a <lb/>Gla&longs;s exceeding 32 Foot) wherein the <lb/>inverted Pipe being long enough to con­<lb/>tain a competent weight of Water, that <lb/>Liquor freely ran out at the lower Orifice: <lb/>Not to mention this (I &longs;ay) we &longs;aw in <lb/>our nineteenth Experiment, that when <lb/>the pre&longs;&longs;ure of the ambient Air was &longs;uffi­<lb/>ciently weaken'd, the Water would fall <lb/>out apace at the Orifice even of a &longs;hort <lb/>Pipe, though the Air could not &longs;ucceed <lb/>into the room de&longs;erted by it. </s> <s>And it were <lb/>not ami&longs;s if tryal were made on the tops <lb/>of very high Mountains, to di&longs;cover with <pb xlink:href="013/01/285.jpg" pagenum="255"/>what ea&longs;e a <emph type="italics"/>Vacuum<emph.end type="italics"/> could be made near <lb/>the confines of the Atmo&longs;phere, where <lb/>the Air is probably but light in compari­<lb/>&longs;on of what it is here below. </s> <s>But our <lb/>pre&longs;ent (three and thirtieth) Experiment <lb/>&longs;eems to manife&longs;t, not onely that the <lb/>power, exerci&longs;'d by Nature, to &longs;hun or re­<lb/>pleni&longs;h a <emph type="italics"/>Vacuum,<emph.end type="italics"/> is limited, but that it <lb/>may be determin'd even to Pounds and <lb/>Ounces: In&longs;omuch that we might &longs;ay, <lb/>&longs;uch a weight Nature will &longs;u&longs;tain or will <lb/>lift up to re&longs;i&longs;t a <emph type="italics"/>Vacuum<emph.end type="italics"/> in our Engine; <lb/>but if an Ounce more be added to that <lb/>weight, it will &longs;urmount Her &longs;o much <lb/>magnifi'd dete&longs;tation of Vacuities. </s> <s>And <lb/>thus, My Lord, our Experiments may <lb/>not onely an&longs;wer tho&longs;e of the Pleni&longs;ts, <lb/>but enable us to retort their Arguments <lb/>again&longs;t them&longs;elves: &longs;ince, if that be true <lb/>which they alleadge, that, when Water <lb/>falls not down according to its nature, in <lb/>a Body wherein no Air can &longs;ucceed to fill <lb/>up the place it mu&longs;t leave, the &longs;u&longs;pen&longs;i­<lb/>on of the Liquor is made <emph type="italics"/>Ne detur Vacu­<lb/>um,<emph.end type="italics"/> (as they &longs;peak) it will follow, that <lb/>if the Water can be brought to &longs;ub&longs;ide <lb/>in &longs;uch a ca&longs;e, that de&longs;erted &longs;pace may be <lb/>deem'd empty, according to their own <lb/>Doctrine; e&longs;pecially, &longs;ince Nature (as <pb xlink:href="013/01/286.jpg" pagenum="256"/>they would per&longs;wade us) be&longs;tirs her &longs;elf <lb/>&longs;o mightily to keep it from being de­<lb/>&longs;erted. </s></p><p type="main"> <s>I hope I &longs;hall not need to reminde Your <lb/>Lord&longs;hip, that I have all this while been <lb/>&longs;peaking of a <emph type="italics"/>Vacuum,<emph.end type="italics"/> not in the &longs;trict <lb/>and Philo&longs;ophical &longs;en&longs;e, but in that more <lb/>obvious and familiar one that has been <lb/>formerly declar'd. </s></p><p type="main"> <s>And therefore I &longs;hall now proceed to <lb/>ob&longs;erve in the la&longs;t place, that our 33<emph type="sup"/>d<emph.end type="sup"/> Ex­<lb/>periment affords us a notable proof of the <lb/>unheeded &longs;trength of that pre&longs;&longs;ure which <lb/>is &longs;u&longs;tain'd by the Corpu&longs;cles of what we <lb/>call the free Air, and pre&longs;ume to be un­<lb/>compre&longs;&longs;'d. </s> <s>For, as fluid and yielding a <lb/>Body as it is, our Experiment teaches us, <lb/>That ev'n in our Climate, and without <lb/>any other compre&longs;&longs;ion then what is (at <lb/>lea&longs;t here below) Natural, or (to &longs;peak <lb/>more properly) ordinary to it, it bears &longs;o <lb/>&longs;trongly upon the Bodies whereunto it is <lb/>contiguous, that a Cylinder of this free <lb/>Air, not exceeding three Inches in Dia­<lb/>meter is able to rai&longs;e and carry up a <lb/>weight, amounting to between &longs;ixteen <lb/>and &longs;eventeen hundred Ounces. </s> <s>I &longs;aid, <pb xlink:href="013/01/287.jpg" pagenum="257"/>even in our Climate, becau&longs;e that is tem­<lb/><arrow.to.target n="marg42"/><lb/>perate enough; and as far as my ob&longs;er­<lb/>vations a&longs;&longs;i&longs;t me to conjecture, the Air in <lb/>many other more Northern Countries <lb/>may be much thicker, and able to &longs;upport <lb/>a greater weight: which is not to be <lb/>doubted of, if there be no mi&longs;take in <lb/>what is Recorded concerning the <emph type="italics"/>Hollan­<lb/>ders,<emph.end type="italics"/> that were forc'd by the Ice to Win­<lb/>ter in <emph type="italics"/>Nova Zembla,<emph.end type="italics"/> namely, That <lb/>they found there &longs;o conden&longs;'d an Air, that <lb/>they could not make their Clock goe, <lb/>ev'n by a very great addition to the <lb/>weights that were wont to move it. </s></p><p type="margin"> <s><margin.target id="marg42"/><emph type="italics"/>Aere frigi­<lb/>do exi&longs;tente <lb/>tardius mo­<lb/>ventur Au­<lb/>tomata <expan abbr="quã">quam</expan> <lb/>aere ca<gap/>ida, <lb/>adco qui­<lb/>dem ut Au­<lb/>tomaton <lb/>quod Belgæ <lb/>in Nova <lb/>Zembla a­<lb/>gentes in æ­<lb/>dibus &longs;uis <lb/>collocave­<lb/>runt, omni­<lb/>no à motis <lb/>ce&longs;&longs;averit <lb/>et&longs;i multo <lb/>maius toa­<lb/>dus ei addidi&longs;&longs;ent quam antea ferre &longs;olebat.<emph.end type="italics"/></s><s> Varenius Geo: Genevat <lb/></s> <s>111. Propo: 7. pag. </s> <s>648.</s></p><p type="main"> <s>I &longs;uppo&longs;e Your Lord&longs;hip will readily <lb/>take notice, that I might very ea&longs;ily have <lb/>di&longs;cour&longs;ed much more fully and accuratly <lb/>then I have done, again&longs;t the common o­<lb/>pinion touching Suction, and touching na­<lb/>tures hatred of a <emph type="italics"/>Vacuum.<emph.end type="italics"/></s><s> But I was willing <lb/>to keep my &longs;elf to tho&longs;e con&longs;iderations <lb/>touching the&longs;e matters, that might be ve­<lb/>rifi'd by our Engine it &longs;elf, e&longs;pecially, &longs;ince, <lb/>as I &longs;aid at fir&longs;t, it would take up too much <lb/>time to in&longs;i&longs;t particularly upon all the Re­<lb/>flections that may be made even upon our <lb/>two la&longs;t Experiments. </s> <s>And therefore, <pb xlink:href="013/01/288.jpg" pagenum="258"/>pa&longs;&longs;ing to the next, I &longs;hall leave it to your <lb/>Lord&longs;hip to con&longs;ider how far the&longs;e tryals <lb/>of ours will either confirm or disfavor <lb/>the new Doctrine of &longs;everal eminent Na­<lb/>turali&longs;ts, who teach, That in all motion <lb/>there is nece&longs;&longs;arily a Circle of Bodies, as <lb/>they &longs;peak, moving together; and whe­<lb/>ther the Circles in &longs;uch motion be an Ac­<lb/>cidental or Con&longs;equential thing or no. </s></p><p type="main"> <s>TIs a known thing to tho&longs;e that are con­<lb/><arrow.to.target n="marg43"/><lb/>ver&longs;ant in the Hydro&longs;taticks, That <lb/>two Bodies which in the Air are of equal <lb/>weight, but of unequal bulk, as Gold, <lb/>for in&longs;tance and Iron, being afterwards <lb/>weighed in Water, will lo&longs;e their <emph type="italics"/>Æqui­<lb/>librium<emph.end type="italics"/> upon the change of the ambient <lb/>Body, &longs;o that the Gold will &longs;ink lower <lb/>then the Iron; which, by rea&longs;on of its <lb/>greater bulk, has more Water to lift <lb/>or di&longs;place, that it may &longs;ink. </s> <s>By Analogy <lb/>to this Experiment, it &longs;eem'd probable, <lb/>that if two weights did in our Engine <lb/>ballance each other, when the Gla&longs;s was <lb/>full of Air; upon the ex&longs;uction of a <lb/>great part of that Air, &longs;o notable a change <lb/>in the con&longs;i&longs;tence of the ambient Body, <pb xlink:href="013/01/289.jpg" pagenum="259"/>would make them lo&longs;e their <emph type="italics"/>Æquili­<lb/>brium.<emph.end type="italics"/></s></p><p type="margin"> <s><margin.target id="marg43"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 34.</s></p><p type="main"> <s>But being de&longs;irous at the &longs;ame time to <lb/>make a tryal, for a certain De&longs;ign that <lb/>needs not here be mention'd, we took <lb/>for one of our weights a dry Bladder, <lb/>&longs;trongly tyed at the Neck, and about <lb/>half fill'd with Air (that being a weight <lb/>both &longs;light, and that would expand it <lb/>&longs;elf in the evacuated Gla&longs;s) and fa&longs;tning <lb/>that to one part of our formerly menti­<lb/>on'd exact ballance (which turns with the <lb/>32<emph type="sup"/>d<emph.end type="sup"/> part of a Grain) we put a Metalline <lb/>counterpoi&longs;e into the oppo&longs;ite Scale; and <lb/>&longs;o the two weights being brought to an <lb/><emph type="italics"/>Æquilibrium,<emph.end type="italics"/> the ballance was convey'd <lb/>into the Receiver, and &longs;u&longs;pended from the <lb/>Cover of it. </s></p><p type="main"> <s>But before we proceed further, we mu&longs;t <lb/>note, That pre&longs;ently after the laying on <lb/>of the Cover, the Bladder appear'd to <lb/>preponderate, whereupon the Scales being <lb/>taken out, and reduc'd very near to an <emph type="italics"/>Æ­<lb/>quilibrium,<emph.end type="italics"/> yet &longs;o, that a little advantage <lb/>remain'd on that &longs;ide to which the Metal­<lb/>line weight belong'd; they were again let <lb/>down into the Receiver, which was pre­<lb/>&longs;ently made fa&longs;t with Plai&longs;ter, and a hot <lb/>Iron: Soon after which, before the Pump <pb xlink:href="013/01/290.jpg" pagenum="260"/>was employ'd, the Bladder &longs;eem'd again <lb/>a little to preponderate. </s> <s>Afterwards <lb/>the Air in the Gla&longs;s being begun to be <lb/>drawn out, the Biadder began (according <lb/>to the formerly mention'd Ob&longs;ervations) <lb/>to expand it &longs;elf, and manife&longs;tly to out­<lb/>weigh the oppo&longs;ite weight, drawing <lb/>down the Scale to which it was fa&longs;tned <lb/>very much beneath the other, e&longs;pecially <lb/>when the Air had &longs;well'd it to its full ex­<lb/>tent. </s></p><p type="main"> <s>This done, we very lei&longs;urely let in the <lb/>external Air; and ob&longs;erv'd, that upon <lb/>the flagging of the Bladder, the Scale <lb/>whereto it was fa&longs;tned, not onely by de­<lb/>grees return'd to an <emph type="italics"/>Æquilibrium<emph.end type="italics"/> with the <lb/>other, but at length was a little out­<lb/>weighed by it. </s></p><p type="main"> <s>But becau&longs;e we &longs;u&longs;pected there <lb/>might have interven'd &longs;ome unheeded <lb/>Circum&longs;tance in this la&longs;t part of the Ex­<lb/>periment, we would not pre&longs;ently take <lb/>out the Scales, nor meddle with the Co­<lb/>ver, but leaving things as they were, we <lb/>perceiv'd, that after a little while the <lb/>Bladder began again to preponderate, and <lb/>by degrees to &longs;ink lower and lower for <lb/>divers hours; wherefore, leaving the <lb/>Ve&longs;&longs;el clo&longs;'d up all night, we repair'd to it <pb xlink:href="013/01/291.jpg" pagenum="261"/>next Morning, and found the Bladder <lb/>fallen yet lower. </s> <s>As if the very &longs;ub&longs;tance <lb/>of it, had imbibed &longs;ome of the moi&longs;ture <lb/>wherewith the Air (the Sea&longs;on being ve­<lb/>ry rainy) did then abound: As Lute­<lb/>&longs;trings, which are made likewi&longs;e of the <lb/>Membranous parts of Guts, &longs;trongly <lb/>wreath'd, are known to &longs;well &longs;o much, <lb/>oftentimes as to break in rainy and wet <lb/>weather. </s> <s>Which conjecture is the more to <lb/>beregarded, becau&longs;e congruou&longs;ly unto it <lb/>one of the company having a little warm'd <lb/>the Bladder, found it then lighter then <lb/>the oppo&longs;ite weight. </s> <s>But this mu&longs;t be <lb/>look'd upon as a bare conjecture, till we <lb/>can gain time to make further tryals about <lb/>it. </s> <s>In the mean while we &longs;hall adde, that <lb/>without removing the Scales or the Co­<lb/>ver of the Receiver, we again cau&longs;'d the <lb/>Air to be drawn out (the weather conti­<lb/>ing very moi&longs;t) but found not any manife&longs;t <lb/>alteration in the ballance; whether be­<lb/>cau&longs;e the <emph type="italics"/>Æquilibrium<emph.end type="italics"/> was too far lo&longs;t to <lb/>let a &longs;mall change appear, we determine <lb/>not. </s></p><p type="main"> <s>But to make the Experiment with a <lb/>Body le&longs;s apt to be altered by the tempe­<lb/>rature of the Air, then was the Bladder; <lb/>we brought the Scales again to an <emph type="italics"/>Æqui-<emph.end type="italics"/><pb xlink:href="013/01/292.jpg" pagenum="262"/><emph type="italics"/>librium<emph.end type="italics"/> with two weights, whereof the <lb/>one was of Lead, the other of Cork. </s> <s>And <lb/>having evacuated the Receiver, we ob&longs;er­<lb/>ved, that both upon the ex&longs;uction, and <lb/>after the return of the Air, the Cork did <lb/>manife&longs;tly preponderate, and much more <lb/>a while after the Air had been let in again, <lb/>then whil&longs;t it was kept out. </s> <s>Wherefore, <lb/>in the room of the Cork, we &longs;ub&longs;tituted <lb/>a piece of Char-coal, as le&longs;s likely to im­<lb/>bibe any moi&longs;ture from the Air, but the <lb/>event proved much the &longs;ame with that <lb/>newly related: So that this Experiment <lb/>&longs;eems more liable to Ca&longs;ualties then any, <lb/>excepting one we have made in our En­<lb/>gine. </s> <s>And as it is difficult to prevent <lb/>them, &longs;o it &longs;eems not very ea&longs;ie to di&longs;­<lb/>cover the cau&longs;es of them, whereof we <lb/>&longs;hall therefore at pre&longs;ent forbear mention­<lb/>ing our Conjectures. </s></p><p type="main"> <s>SOme Learned Mathematicians have of <lb/><arrow.to.target n="marg44"/><lb/>late ingenioù&longs;ly endeavored to reduce <lb/>Filters to <emph type="italics"/>Siphons;<emph.end type="italics"/> but &longs;till the true cau&longs;e <lb/>of the a&longs;cen&longs;ion of Water, and other Li­<lb/>quors, both in <emph type="italics"/>Siphons<emph.end type="italics"/> and in Filtration, <lb/>needing (for ought we have yet found) a <lb/>clearer Di&longs;covery and Explication, we <pb xlink:href="013/01/293.jpg" pagenum="263"/>were de&longs;irous to try whether or no the <lb/>pre&longs;&longs;ure of the Air might rea&longs;onably be <lb/>&longs;uppo&longs;'d to have either the principal, or at <lb/>lea&longs;t a con&longs;iderable Intere&longs;t in the rai&longs;ing <lb/>of tho&longs;e Liquors. </s> <s>But becau&longs;e we found <lb/>that we could not yet &longs;o evacuate our Re­<lb/>ceiver, but that the remaining Air, <lb/>though but little in compari&longs;on of the <lb/>exhau&longs;ted, would be able to impell the <lb/>the Water to a greater height then is <lb/>u&longs;ual in ordinary Filtrations: we re&longs;olved, <lb/>in&longs;tead of a Li&longs;t of Cotton, or the like <lb/>Filtre, to make u&longs;e of a <emph type="italics"/>Siphon<emph.end type="italics"/> of Gla&longs;s, <lb/>delineated in the third Figure, con&longs;i&longs;t­<lb/>ing of three pieces, two &longs;traight, and <lb/>the third crooked to joyn them toge­<lb/>ther; who&longs;e Junctures were diligently <lb/>clo&longs;'d, that no Air might finde entrance <lb/>at them. </s> <s>One of the Legs of this <emph type="italics"/>Si­<lb/>phon<emph.end type="italics"/> was (as it &longs;hould be) &longs;omewhat <lb/>longer then the other, and was pervious <lb/>at the bottom of it onely, by a hole al­<lb/>mo&longs;t as &longs;lender as a hair, that the <lb/>Water might but very lea&longs;urely drop <lb/>out of it, le&longs;t it &longs;hould all run out <lb/>before the Experiment were compleat­<lb/>ed. </s> <s>The other and &longs;horter Leg of <lb/>the <emph type="italics"/>Siphon<emph.end type="italics"/> was quite open at the end, <lb/>and of the &longs;ame widene&longs;&longs;e with the <pb xlink:href="013/01/294.jpg" pagenum="264"/>re&longs;t of the Pipe, who&longs;e bore was about <gap/>/4 <lb/>of an Inch. </s> <s>The whole Siphon made <lb/>up of the&longs;e &longs;everal pieces put together, <lb/>was de&longs;ign'd to be about a Foot and a <lb/>half long; that the remaining Air, when <lb/>the Ve&longs;&longs;el was exhau&longs;ted after the wont­<lb/>ed manner, might not be able to impell <lb/>the Water to the top of the <emph type="italics"/>Siphon;<emph.end type="italics"/><lb/>which being inverted, was fill'd with Wa­<lb/>ter, and of which the Shorter leg being <lb/>let down two or three Inches deep into a <lb/>Gla&longs;s Ve&longs;&longs;el full of Water, and the up­<lb/>per parts of it being fa&longs;ten'd to the in&longs;ide <lb/>of the Cover of the Receiver, we pro­<lb/>ceeded to clo&longs;e fir&longs;t, and then to empty <lb/>the Ve&longs;&longs;el. </s></p><p type="margin"> <s><margin.target id="marg44"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 35.</s></p><p type="main"> <s>The effect of the tryal was this, that <lb/>till a pretty quantity of Air had been <lb/>drawn out, the Water dropp'd freely out <lb/>at the lower end of the lower leg of the <lb/><emph type="italics"/>Siphon,<emph.end type="italics"/> as if the Experiment had been <lb/>performed in the free Air. </s> <s>But afterwards, <lb/>the Bubbles (as had been apprehended) <lb/>began to di&longs;clo&longs;e them&longs;elves in the Wa­<lb/>ter, and a&longs;cending to the top of the <emph type="italics"/>Si­<lb/>phon,<emph.end type="italics"/> imbodyed them&longs;elves there into <lb/>one, which was augmented little by little <lb/>by the ri&longs;ing of other bubbles that from <lb/>time to time broke into it, but much <pb xlink:href="013/01/295.jpg" pagenum="265"/> more by its own dilatation, which en-<lb/>crea&longs;'d proportionably to the ex&longs;uction<lb/> that was made of the Air out of the Re-<lb/>ceiver.</s> <s>So that at length the Water in<lb/> the &longs;horter Leg of the <emph type="italics"/>Siphon<emph.end type="italics"/>was re-<lb/>duc'd partly by the extraction of the am-<lb/>bient Air, and partly by the expan&longs;ion<lb/> of the great Bubble at the upper part of<lb/> the <emph type="italics"/>Siphon<emph.end type="italics"/>, to be but about a Foot high,<lb/> if &longs;o much; wherby it came to pa&longs;s,<lb/> that the cour&longs;e of the Water in the <emph type="italics"/>Si-<lb/>phon<emph.end type="italics"/> was interrupted, and that which re-<lb/>main'd in the longer Leg of it, continu'd<lb/> &longs;u&longs;pended there without dropping any<lb/> longer.</s> <s>But upon the turning of the<lb/> Stop-cock, the outward Air (being t<lb/> into the Receiver) got into the <emph type="italics"/>Siphon<emph.end type="italics"/> by<lb/> the little hole at which the Water former-<lb/>ly dropt out; and traver&longs;ing all the in-<lb/>cumbent Cylinder of Water, in the form<lb/> of Bubbles, joyn'd it &longs;elf with that Air<lb/> that before po&longs;longs;e&longs;longs;'d the top of the <emph type="italics"/>Si-<lb/>phon<emph.end type="italics"/>.</s></p> <p type="main"><s>To prevent the inconveniences ari&longs;ing<lb/> from the&longs;e Bubbles, two Gla&longs;s Pipes, like <lb/> the former; were &longs;o placed; as to termi-<lb/>nate together in the mid&longs;t of the Belly of<lb/> a Gla&longs;s Viol, into who&longs;e Neck they<lb/> were carefully fa&longs;tned with Cement; and<pb xlink:href="013/01/296.jpg" pagenum="266"/> then both the Viols and the Pipes being<lb/> (which was not the not done without difficulty)<lb/> totally fill'd with Water, the <emph type="italics"/>Siphon<emph.end type="italics"/><lb/> de&longs;crib'd in the fifth Figure, was plac'd<lb/> with its &longs;horter Leg in the Gla&longs;s of Wa-<lb/>ter, as formerly; and the Experiment be-<lb/>ing pro&longs;ecuted after the &longs;ame manner,<lb/> much more Air then formerly was drawn<lb/> out, before the Bubbles di&longs;closing them-<lb/>&longs;elves in the Water were able to di&longs;turb<lb/> the Experiment; becau&longs;e that in the ca-<lb/>pacity of the Viol there was room enough<lb/> for them to &longs;tretch them&longs;elves, without<lb/> depre&longs;&longs;ing the Water below the ends of<lb/> the Pipes; and, during this time, the<lb/> Water continued to drop out of the pro-<lb/>pending Leg of the <emph type="italics"/>Siphon<emph.end type="italics"/>.</s> <s>But at<lb/> length the Receiverbeing very much em-<lb/>pty'd, the pa&longs;&longs;age of the Water through<lb/> the <emph type="italics"/>Siphon<emph.end type="italics"/>cea&longs;'d, the upper ends of the<lb/> Pipes beginning to appear a little above<lb/> the remaining Water in the Viol, who&longs;e<lb/> dilated Air appear'd likewi&longs;e to pre&longs;s<lb/> down the Water in the Pipes, and fill the<lb/> upper part of them.</s> <s>And hereby the con-<lb/>tinuity of the Water, and &longs;o the Expe-<lb/>riment it &longs;elf being interrupted, we were<lb/> invited to let in the air again, which, ac-<lb/>cording to its various proportions of<pb xlink:href="013/01/297.jpg" pagenum="267"/> pre&longs;&longs;ure to that of the Air in the Viol<lb/> and the Pipes, did for a good while exhi-<lb/>bite a plea&longs;ing variety of <emph type="italics"/>Phaenomena<emph.end type="italics"/>,<lb/> which we have not now the lei&longs;ure to re-<lb/>cite.</s> <s>And though upon the whole mat-<lb/>ter there &longs;eem'd little or no cau&longs;e to<lb/> doubt, but that, if the Bubbles had not<lb/> di&longs;turb'd the Experiment, it would mani-<lb/>fe&longs;tly enough have appear'd that the<lb/> cour&longs;e of Water through <emph type="italics"/>Siphons<emph.end type="italics"/> de-<lb/>pends upon the pre&longs;&longs;ure of the Air: yet<lb/> we re&longs;olv'd, at our next lei&longs;ure and con-<lb/>veniency, to try the Experiment again,<lb/> with a quantity of Water before freed<lb/> from Bubbles by the help of the &longs;ame<lb/> Engine.</s></p> <p type="main"><s>This occa&longs;ion I have had to take notice<lb/> of <emph type="italics"/>Siphons<emph.end type="italics"/>, puts me in minde of an odde<lb/> kinde of <emph type="italics"/>Siphon<emph.end type="italics"/> that I cau&longs;'d to be made<lb/> a pretty while ago; and which has been<lb/> &longs;ince, by an Ingenious Man of Your ac-<lb/>quaintance, communicated to divers o-<lb/>thers.</s> <s>This occa&longs;ion was this, An emi-<lb/>nent Mathematician told me one day, that<lb/> &longs;ome inqui&longs;itive French Men (who&longs;e<lb/> Names I know not) had ob&longs;erv'd, That,<lb/> in ca&longs;e one end of a flender and perforated<lb/> Pipe of Gla&longs;s be dipt in Water, the Li-<pb xlink:href="013/01/298.jpg" pagenum="268"/>quor will a&longs;cend to &longs;ome height in the<lb/>Pipe, though held perpendicular to the<lb/>plain of the Water.</s> <s>And, to &longs;atisfie me<lb/> that he mi&longs;-related not the Experiment,<lb/> he &longs;oon after brought two or three<lb/>&longs;mall Pipes of Gla&longs;s, which gave me the<lb/> opportunity of trying it: though I had<lb/>the le&longs;s rea&longs;on to di&longs;tru&longs;t it, becau&longs;e I re-<lb/>member I had often in the long and flen-<lb/>der Pipes of &longs;ome Weather Gla&longs;&longs;as,<lb/> which I had cau&longs;'d to be made after a<lb/>&longs;omewhat peculiar fa&longs;hion, taken notice<lb/> of the like a&longs;cen&longs;ion of the Liquor,<lb/> though (pre&longs;uming it might be ca&longs;ual) I<lb/> had made but litllereflection upon it.</s> <s>But<lb/> after this tryal, beginning to &longs;uppo&longs;e, that<lb/> though the Water in the&longs;e Pipes that<lb/> were brought me, ri&longs;e not above a quar-<lb/>ter of an Inch, (if near &longs;o high) yet, if<lb/> the Pipes were made flender enough, the<lb/> water might ri&longs;e to a very much greater<lb/> height; I cau&longs;'d &longs;everal of them to be, by<lb/> a dexterous Hand, drawn out at the flame<lb/> of a Lamp, in one of which that was<lb/> almo&longs;t incredibly flender, we found that<lb/> the Water as&longs;ended (as it were of it &longs;elf)<lb/> five Inches by mea&longs;ure, to the no &longs;mall<lb/> wonder of &longs;ome famous Mathematicians,<lb/> who were Spectators of &longs;ome of the&longs;e<pb xlink:href="013/01/299.jpg" pagenum="269"/>Experiments.</s> <s>And this height the Wa-<lb/>ter reach'd to, though the Pipe were held<lb/> in as erected a po&longs;ture as we could: For if<lb/> it were inclin'd, the Water would fill a<lb/> greater part of it, though not ri&longs;e higher<lb/> in it.</s> <s>And we al&longs;o found, that when the<lb/> in&longs;ide of the Pipe was wetted before-<lb/>hand, the Water would ri&longs;e much better<lb/> then otherways: But we cau&longs;'d not all<lb/> our flender Pipes to be made &longs;traight, but<lb/> &longs;ome of them crooked, like <emph type="italics"/>Siphons<emph.end type="italics"/>: And<lb/> having immer&longs;'d the &longs;horter Leg of one<lb/> of the&longs;e into a Gla&longs;s that held &longs;ome fair<lb/> Water, we found, as we expected, that<lb/> the Water ari&longs;ing to the top of the <emph type="italics"/>Si-<lb/>phon<emph.end type="italics"/>, though that were high enough, did<lb/> of it &longs;elf run down the longer Leg, and <lb/> continue running like an ordinary <emph type="italics"/>Siphon<emph.end type="italics"/>.<lb/></s> <s>The cau&longs;e of this a&longs;cen&longs;ion of the Wa-<lb/>ter, appear'd to all that were pre&longs;ent &longs;o<lb/> difficult, that I mu&longs;t not &longs;tay to enumerate<lb/> the various Conjectures that were made<lb/> at it, much le&longs;s to examine them; e&longs;pe-<lb/>cially, having nothing but bare Conje-<lb/>ctures to &longs;ub&longs;titute in the room of tho&longs;e<lb/> I do not approve.</s> <s>We try'd indeed, by <lb/> conveying a very flender Pipe and a &longs;mall<lb/> Ve&longs;&longs;el of Water into our Engine, whe-<lb/>ther or no the Ex&longs;uction of the ambient<pb xlink:href="013/01/300.jpg" pagenum="270"/> Air would a&longs;&longs;i&longs;t us to finde the cau&longs;e of<lb/> the a&longs;cen&longs;ion we have been &longs;peaking of:<lb/> But though we imploy'd red Wine in-<lb/>&longs;tead of Water, yet we could fearce cer-<lb/>tainly perceive thorow &longs;o much Gla&longs;s, as<lb/> was interpo&longs;'d betwixt our Eyes and the<lb/>Liquor, what happen'd in a Pipe &longs;o flen-<lb/>der, that the redne&longs;s of the Wine was<lb/> &longs;carce &longs;en&longs;ible in it.</s> <s>But as far as we could<lb/>di&longs;cern, there happen'd no great altera-<lb/>tion to the Liquor: which &longs;eem'd the le&longs;s<lb/> &longs;trange, becau&longs;e the Spring of that Air<lb/> that might depre&longs;s the Water in the Pipe,<lb/> was equally debilitated with that which<lb/> remain'd to pre&longs;s upon the &longs;urface of the<lb/> Water in the little Gla&longs;s.</s> <s>Wherefore, in<lb/> favor of his Ingenious Conjecture who<lb/> a&longs;crib'd the <emph type="italics"/>Phaenomenon<emph.end type="italics"/>, under con&longs;ide-<lb/>ration to the greater pre&longs;&longs;ure made upon<lb/> the Water by the Air without the Pipe,<lb/> then by that within it, (where &longs;o much of<lb/> the Water (con&longs;i&longs;ting perhaps of Corpu-<lb/>&longs;cles more pliant to the internal &longs;urfaces of<lb/> the Air) was contiguous to the &longs;ides) it<lb/> was &longs;hown, that in ca&longs;e the little Gla&longs;s<lb/> Ve&longs;&longs;el that held the Water, of which a<lb/> part a&longs;cended into the flender Pipe, were<lb/> &longs;o clo&longs;'d, that a Man might with his mouth<lb/> &longs;uck the Air out of it, the Water would <pb xlink:href="013/01/301.jpg" pagenum="271"/> immediately &longs;ub&longs;ide in the &longs;mall Pipe.<lb/></s> <s>And this would indeed infer, that it a&longs;-<lb/>cended before onely by the pre&longs;&longs;ure of<lb/> the incumbent Air: But that it may<lb/> (how ju&longs;tly I know not) be objected,<lb/> that preadventure this would not hap-<lb/>pen, in ca&longs;e the upper ende of the Pipe<lb/> were in a <emph type="italics"/>Vacuum<emph.end type="italics"/>: And that 'tis very<lb/> probable the Water may &longs;ub&longs;ide, not<lb/> becau&longs;e the pre&longs;&longs;ure of the internal Air<lb/> is taken off by Ex&longs;uction, but by rea&longs;on<lb/> of the Spring of the external Air,<lb/> which impels the Water it findes in its<lb/> way to the Cavity de&longs;erted by the<lb/> other Air, and would as well impell<lb/> the &longs;ame Water upwards, as make it<lb/> &longs;ub&longs;ide, if it were not now lei&longs;ure to exa-<lb/>mine any further this Matter, I &longs;hall<lb/> onely minde Your Lord&longs;hip, that if<lb/> You will pro&longs;ecute this Speculation,<lb/> it will be pertinent to finde out likewi&longs;e,<lb/> Why the &longs;urface of Water /as is manife&longs;t<lb/> in Pipes) u&longs;es to be concave, being de-<lb/>pre&longs;&longs;'d in the middle, and higher on eve-<lb/>ry side? and Why in Quick-&longs;ilver on the<lb/> contrary, not onely the &longs;urface is wont <pb xlink:href="013/01/302.jpg" pagenum="272"/> to be very convex, or &longs;welling, in the<lb/> middle; but if you dip the end of a flen-<lb/>der Pipe in it, the &longs;urface of the Li-<lb/>quor (as 'tis call'd) will be lower within<lb/> the Pipe, then without.</s> <s>Which <emph type="italics"/>Phaeno-<lb/>mena<emph.end type="italics"/>, whether, and how far, they may<lb/> be deduc'd from the Figure of the Mer-<lb/>curial Corpu&longs;cles, and the Shape of the<lb/> Springy Particles of the Air, I willingly<lb/> leave to be con&longs;ider'd.</s></p> <p type="main"><s><arrow.to.target n="marg441"/>SEveral ways we have met with pro-<lb/>po&longs;'d, partly by the excellent <emph type="italics"/>Galileo<emph.end type="italics"/>,<lb/> and partly by other ingenious Writers,<lb/> to manife&longs;t that the Air is not devoid of<lb/> weight; &longs;ome of the&longs;e, require the previ-<lb/>ous ab&longs;ence of the Air to be weighed;<lb/> and others, the violent conden&longs;ation of it.<lb/></s> <s>But if we could lift a pair of Scales above<lb/> the Atmo&longs;phere, or place them in a <emph type="italics"/>Va-<lb/>cuum<emph.end type="italics"/>, we might there weigh a parcel of<lb/> Air it &longs;elf, as here we do other Bodies in<lb/> the Air, becau&longs;e it would there be heavi-<lb/>er then that which &longs;urrounds it, as are<lb/>gro&longs;&longs;er Bodies we commonly weigh, then<lb/> the medium or ambient Air.</s> <s>Where-<lb/>fore, though we have above declin'd to<lb/> affirm, that our Receiver, when empty-<pb xlink:href="013/01/303.jpg" pagenum="273"/>ed, de&longs;erves the name of a true <emph type="italics"/>Vacuum<emph.end type="italics"/>,<lb/> and though we cannot yet perfectly free<lb/> it from Air it &longs;elf, yet we thought fit to<lb/><lb/> try how far the Air would manife&longs;t its<lb/> gravity in &longs;o thin a medium, as we could<lb/> make in our Receiver, by evacuating it.<lb/></s> <s>We cau&longs;'d then to be blown at the Flame<lb/> of a Lamp, a Gla&longs;s-bubble of about<lb/> the bigne&longs;s of a small Hen egge, and of<lb/> an Oval form, &longs;ave that at one end there<lb/> was drawn out an exceeding flender Pipe,<lb/> that the Bubble might be &longs;eal'd up, with<lb/> as little rarifaction as might be, of the<lb/> Air included in the great or ovall Cavi-<lb/>ty of it.</s> <s>This Gla&longs;s being &longs;eal'd, was fa-<lb/>&longs;tened to one of the Scales of the exact<lb/> pair of Ballances formerly mention'd;<lb/> and being counterpoi&longs;'d with a weight of<lb/> Lead, was convey'd into the Receiver,<lb/> and clo&longs;'d up in it.</s> <s>The Beam appearing<lb/> to continue Horizontal, the Pump was &longs;et<lb/> awork, and there &longs;carce pa&longs;t above two<lb/> or three Ex&longs;uctions of the Air, before<lb/> the Ballance lo&longs;t its <emph type="italics"/>Aequilibrium<emph.end type="italics"/>, and<lb/> began to incline to that &longs;ide on which<lb/> the Bubble was; which, as the Air was<lb/> further and further drawn out, did mani-<lb/>fe&longs;tly more and more preponderate, till<lb/> he that pump'd began to grow weary of<pb xlink:href="013/01/304.jpg" pagenum="274"/> his Imployment: after which the aire be-<lb/>ing lea&longs;urely let in againe, the &longs;cales by<lb/> degrees returned to their former <emph type="italics"/>Aequili-<lb/>brium<emph.end type="italics"/>.</s> <s>After that we tooke them out, and<lb/> ca&longs;ting into that &longs;cale to which the lead<lb/> belong'd three quarters of a grain, we<lb/> convey'd the ballance into the Recei-<lb/>ver, which being clo&longs;ed up, and exhau-<lb/>&longs;ted as before, we ob&longs;erv'd, that as the<lb/> aire was drawne out more and more, &longs;o<lb/> the gla&longs;&longs;e bubble came neerer and neer-<lb/>er to an <emph type="italics"/>Aequilibrium<emph.end type="italics"/> with the other<lb/> weight, till at length the beame was<lb/> drawne to hang horizontall; which (as<lb/> we had found by another tryall) wee<lb/> could not bring it to do, when a quar-<lb/>ter of a Graine more was added to<lb/> the &longs;cale, to which the lead belong'd:<lb/> though it &longs;eem'd que&longs;tionle&longs;&longs;e, that if<lb/> wee could have perfectly empty'd the<lb/> Receiver of the contain'd aire, that in-<lb/>cluded, in the bubble would have weigh-<lb/>ed above a grain, notwith&longs;tanding its<lb/> having been probably &longs;omewhat Rari-<lb/>fy'd by the flame by the help of which,<lb/> the bubble was &longs;eald up.</s> <s>Let us adde,<lb/> that on the regre&longs;&longs;e of the excluded<lb/> air, the Lead, and the weight ca&longs;t into the <pb xlink:href="013/01/305.jpg" pagenum="275"/>&longs;ame &longs;cale, did againe very much pre-<lb/>ponderate.</s></p> <p type="margin"><s><margin.target id="marg441"/><emph type="italics"/>Experi-<lb/>ment 36.<emph.end type="italics"/></s></p> <p type="main"><s>We likewi&longs;e convey'd into the Re-<lb/>ceiver, the &longs;ame bubble, open'd at<lb/> the end of the flender pipe above men-<lb/>tioned, but having drawne out the aire,<lb/> after the accu&longs;tomed manner, we found<lb/> not as before, the bubble to out-weigh<lb/> the oppo&longs;ite lead, &longs;o that by the help<lb/> of our Engine, we can weigh the Aire,<lb/> as we weigh other Bodies, in its na-<lb/>turall or ordinary con&longs;i&longs;tence, without<lb/> at all conden&longs;ing it: Nay, which is re-<lb/>markable, having convey'd a Lamb's<lb/> bladder about halfe full of Aire into the<lb/> Receiver, wee ob&longs;erved, that though<lb/> upon the drawing out of the ambient<lb/>aire the impri&longs;oned Air &longs;o expended<lb/> it &longs;elf, as to di&longs;tend the Bladder &longs;o, as to<lb/> &longs;eem ready to break it, yet this rarified<lb/> Air did manife&longs;tly depre&longs;s the Scale<lb/> whereunto it was annexed.</s></p> <p type="main"><s>Another thing, we mu&longs;t not forget to<lb/> mention, that happend to us, whil'&longs;t we were<lb/> making tryals concerning the weight of the<lb/> Air; namely, That having once cau&longs;'d the<pb xlink:href="013/01/306.jpg" pagenum="276"/> Pump to be &longs;omewhat ob&longs;tinately ply'd,<lb/> to di&longs;cover the better what may be ex-<lb/>pected from the thinne&longs;s of the medium<lb/> in this Experiment; the Impri&longs;on'd Air<lb/> broke its brittle Pri&longs;on, and throwing the<lb/> greate&longs;t part of it again&longs;t the &longs;ide of the<lb/> Receiver, da&longs;h'd it again&longs;t that thick Gla&longs;s<lb/> into a multitude of pieces.</s> <s>Which Acci-<lb/>dent I mention, partly that it may con-<lb/>firm what we deliver'd in our Reflections,<lb/> upon the fir&longs;t Experiment, where we con-<lb/>&longs;ider'd what would probably be done by<lb/> the Spring of Air Impri&longs;on'd in &longs;uch<lb/> Gla&longs;&longs;es, in ca&longs;e the ballancing pre&longs;&longs;ure of<lb/> the ambient Air were withdrawn; and<lb/> partly, that we may thence di&longs;cern of how<lb/> clo&longs;e a Texture Gla&longs;s is, &longs;ince &longs;o very<lb/> thin a film of Gla&longs;s (if I may &longs;o call it)<lb/> prov'd &longs;o impervious to the Air, that it<lb/> could not get away through the Pores,<lb/> but was forc'd to break the gla&longs;s in pieces<lb/> to free it &longs;elf; and this, notwith&longs;tanding<lb/> the time and advantage it had to try to<lb/> get out at the Pores.</s> <s>And this I mention,<lb/> that neitherour Experiments, nor tho&longs;e<lb/> of divers Learned Men, might receive<lb/> any prejudice from an Experiment which<lb/> I happen'd to make divers years ago, and,<lb/> which having been &longs;o much taken notice<pb xlink:href="013/01/307.jpg" pagenum="277"/> of by curious Men, may be drawn to<lb/> countenance their erroneous Opinion, who<lb/> would fain per&longs;wade us, That Gla&longs;s is<lb/> penetrable by Air properly &longs;o called.</s> <s>Our<lb/> Experiment was briefly this: We were<lb/> di&longs;tilling a certain &longs;ub&longs;tance, that much a-<lb/>bounded with &longs;ubtle Spirits and volatile<lb/> Salt, in a &longs;trong Earthen-ve&longs;&longs;el of an un-<lb/>u&longs;ual &longs;hape, to which was luted a large<lb/> Receiver, made of the cour&longs;er &longs;ort of<lb/> Gla&longs;s, (which the Trades-men are wont<lb/> to call Green-gla&longs;s) but in our ab&longs;ence,<lb/> the Fire, though it were to be very &longs;trong,<lb/> was by the negligence or mi&longs;take of tho&longs;e<lb/> we appointed to attend it, &longs;o exce&longs;&longs;ively<lb/> increa&longs;'d, that when we came back to the<lb/> Fornace we found the Spirituous and Sa-<lb/>line Corpu&longs;cles pour'd out (if I may &longs;o<lb/> call it) &longs;o hot, and &longs;o copiou&longs;ly into the<lb/> Receiver, that they made it all opacous,<lb/> and more likely to flie in pieces, then fit<lb/> to be touch'd.</s> <s>Yet, being curious to ob-<lb/>&longs;erve the effects of a Di&longs;tillation, pr&longs;e-<lb/>cuted with &longs;o inten&longs;e and unu&longs;ual degree<lb/> of heat, we ventur'd to come near, and<lb/> ob&longs;erv'd among other things, that on the<lb/> out-&longs;ide of the Receiver, at a great di-<lb/>&longs;tance from the juncture, there was &longs;etled<lb/> a round whiti&longs;h Spot or two, which at<pb xlink:href="013/01/308.jpg" pagenum="278"/>fir&longs;t we thought might be &longs;ome &longs;tain up­<lb/>on the Gla&longs;s; but after, finding it to <lb/>be in divers Qualities like the Oyl, <lb/>and Salt of the Concrete we were Di­<lb/>&longs;tilling, we began to &longs;u&longs;pect that the <lb/>mo&longs;t &longs;ubtle and fugitive parts of the im­<lb/>petuou&longs;ly a&longs;cending Steams, had pene­<lb/>trated the &longs;ub&longs;tance (as they &longs;peak) of <lb/>the Gla&longs;s, and by the cold of the am­<lb/>bient Air were conden&longs;'d on the &longs;ur­<lb/>face of it. </s> <s>And though we were ve­<lb/>ry backward to credit this &longs;u&longs;pition, and <lb/>therefore call'd in an Ingenious Per&longs;on <lb/>or two, both to a&longs;&longs;i&longs;t us in the Ob­<lb/>&longs;ervation, and have Witne&longs;s of its e­<lb/>vent, we continued a while longer to <lb/>watch the e&longs;cape of &longs;uch unctuous Fumes, <lb/>and upon the whole matter unanimou&longs;ly <lb/>concluded, That all things con&longs;ider'd, <lb/>the &longs;ubtle parts of the di&longs;till'd matter <lb/>being violently agitated, by the exce&longs;­<lb/>&longs;ive heat had pa&longs;&longs;'d through the Pores <lb/>of the Gla&longs;s, widen'd by the &longs;ame heat. <lb/></s> <s>But this having never happen'd but <lb/>once in any of the Di&longs;tillations we have <lb/>either made or &longs;een, though the&longs;e be <lb/>not a few, it is much more rea&longs;onable <lb/>to &longs;uppo&longs;e, that the perviou&longs;ne&longs;s of <lb/>our Receiver to a Body much more <pb xlink:href="013/01/309.jpg" pagenum="279"/>&longs;ubtle then Air, proceeded partly from <lb/>the loo&longs;er Texture of that particular <lb/>parcel of Gla&longs;s the Receiver was made <lb/>of (for Experience has taught us, that <lb/>all Gla&longs;s is not of the &longs;ame compact­<lb/>ne&longs;s and &longs;olidity) and partly from the <lb/>enormous heat, which, together with <lb/>the vehement agitation of the pene­<lb/>trant Spirits, open'd the Pores of the <lb/>Gla&longs;s; then to imagine that &longs;uch a <lb/>&longs;ub&longs;tance as Air, &longs;hould be able to per­<lb/>meate the Body of Gla&longs;s contrary to <lb/>the te&longs;timony of a thou&longs;and Chymical <lb/>and Mechanical Experiments, and of <lb/>many of tho&longs;e made in our Engine, e­<lb/>&longs;pecially that newly recited: Nay, by <lb/>our fifth Experiment it appears, that <lb/>a thin Bladder will not at its Pores <lb/>give pa&longs;&longs;age even to rarified Air. </s> <s>And <lb/>on this occa&longs;ion we will annex an Ex­<lb/>periment, which has made &longs;ome of <lb/>tho&longs;e we have acquainted with it, <lb/>doubt, whether the Corpu&longs;cles of the <lb/>Air be not le&longs;&longs;e &longs;ubtle then tho&longs;e of <lb/>Water. </s></p><p type="main"> <s>But without examining here the <lb/>rea&longs;onablene&longs;&longs;e of that doubt, we will <lb/>proceed to recite the Experiment it &longs;elf, <lb/>which &longs;eems to teach, That though Air, <pb xlink:href="013/01/310.jpg" pagenum="280"/>when &longs;ufficiently compre&longs;&longs;'d, may per­<lb/>chance get entrance into narrower holes <lb/>and crannies then Water; yet unle&longs;s the <lb/>Air be forc'd in at &longs;uch very little holes, <lb/>it will not get in at them, though they <lb/>may be big enough to let Water pa&longs;s <lb/>through them. </s></p><p type="main"> <s>The Experiment then was this: I took <lb/>a fair Gla&longs;s <emph type="italics"/>Siphon,<emph.end type="italics"/> the lower end of <lb/>who&longs;e longe&longs;t Leg was drawn by degrees <lb/>to &longs;uch a &longs;lenderne&longs;s, that the Orifice, at <lb/>which the Water was to fall out, would <lb/>hardly admit a very &longs;mall Pin: This <emph type="italics"/>Si­<lb/>phon<emph.end type="italics"/> being inverted, the matter was &longs;o <lb/>order'd, that a little Bubble of Air was <lb/>intercepted in the &longs;lendere&longs;t part of the <lb/><emph type="italics"/>Siphon,<emph.end type="italics"/> betwixt the little hole newly men­<lb/>tion'd, and the incumbent Water, upon <lb/>which, it came to pa&longs;s, that the Air be­<lb/>ing not to be forc'd through &longs;o narrow a <lb/>pa&longs;&longs;age, by &longs;o light a Cylinder of Water, <lb/>though amounting to the length of divers <lb/>Inches, as lean'd upon it, hinder'd the <lb/>further Efflux of the Water, as long as I <lb/>plea&longs;'d to let it &longs;tay in that narrow place: <lb/>whereas, when by blowing a little at the <lb/>wider end of the <emph type="italics"/>Siphon,<emph.end type="italics"/> that little par­<lb/>cel of Air was forc'd out with &longs;ome Wa­<lb/>ter, the remaining Water, that before <pb xlink:href="013/01/311.jpg" pagenum="281"/>continu'd &longs;u&longs;pended, began freely to drop <lb/>down again as formerly. </s> <s>And if you <lb/>take a Gla&longs;s Pipe, whether it be in the <lb/>form of a <emph type="italics"/>Siphon,<emph.end type="italics"/> or no, that being for <lb/>the mo&longs;t part of the thickne&longs;s of a Mans <lb/>Finger, is yet towards one end &longs;o &longs;len­<lb/>der, as to terminate in a hole almo&longs;t as <lb/>&longs;mall as a Hor&longs;e-hair; and if you fill this <lb/>Pipe with Water, you will finde that Li­<lb/>quor to drop down freely enough tho­<lb/>row the &longs;lender Extream: But if you then <lb/>invert the Pipe, you will finde that the <lb/>Air will not ea&longs;ily get in at the &longs;ame hole <lb/>through which the Water pa&longs;&longs;'d. </s> <s>For in <lb/>the &longs;harp end of the Pipe, &longs;ome Inches <lb/>of Water will remain &longs;u&longs;pended, which <lb/>'tis probable would not happen, if the <lb/>Air could get in to &longs;ucceed it, &longs;ince if the <lb/>hole were a little wider, the Water would <lb/>immediatly &longs;ub&longs;ide. </s> <s>And though it be <lb/>true, that if the Pipe be of the length of <lb/>many Inches, a great part of the Wa­<lb/>ter will run down at the wider Orifice, yet <lb/>that &longs;eems to happen for &longs;ome other rea­<lb/>&longs;on, then becau&longs;e the Air &longs;ucceeds it at <lb/>the upper and narrow Orifice, &longs;ince all the <lb/>&longs;lender part of the Pipe, and perhaps <lb/>&longs;ome Inches more, will continue full of <lb/>Water. </s></p><pb xlink:href="013/01/312.jpg" pagenum="282"/><p type="main"> <s>And on this occa&longs;ion I remember, that <lb/>whereas it appears by our fifth Experi­<lb/>ment, That the Aërial Corpu&longs;cles (ex­<lb/>cept perhaps &longs;ome that are extraordinari­<lb/>ly fine) will not pa&longs;&longs;e thorow the Pores <lb/>of a Lambs Bladder, yet Particles of Wa­<lb/>ter will, as we have long &longs;ince ob&longs;erv'd, <lb/>and as may be ea&longs;ily try'd, by very clo&longs;e­<lb/>ly tying a little <emph type="italics"/>Alcalizate<emph.end type="italics"/> Salt (we u&longs;'d <lb/>the Calx of Tartar, made with Nitre) <lb/>in a fine Bladder, and dipping the lower <lb/>end of the Bladder in Water; for if you <lb/>hold it there for a competent while, you <lb/>will finde that there will &longs;train thorow the <lb/>Pores of the Bladder Water enough to <lb/>di&longs;&longs;olve the Salt into a Liquor. </s></p><p type="main"> <s>But I &longs;ee I am &longs;lipt into a Digre&longs;&longs;ion, <lb/>wherefore I will not examine, whether, <lb/>the Experiment I have related, proceed­<lb/>ed from hence, That the &longs;pringy Texture <lb/>of the Corpu&longs;cles of the Air, makes <lb/>them le&longs;s apt to yield and accommodate <lb/>them&longs;elves ea&longs;ily to the narrow Pores of <lb/>Bodies, then the more flexible Particles <lb/>of Water; or whether it may more pro­<lb/>babiy be a&longs;crib'd to &longs;ome other Cau&longs;e. <lb/></s> <s>Nor will I &longs;tay to con&longs;ider how far we may <lb/>hence be a&longs;&longs;i&longs;ted to ghe&longs;s at the cau&longs;e of <lb/>the a&longs;cen&longs;ion of Water in the &longs;lender <pb xlink:href="013/01/313.jpg" pagenum="283"/>Pipes and <emph type="italics"/>Siphons<emph.end type="italics"/> formerly mention'd, <lb/>but will return to our Bubble; and take <lb/>notice, That we thought fit al&longs;o to en­<lb/>deavor to mea&longs;ure the capacity of the <lb/>Bubble we had made u&longs;e of, by filling <lb/>it with Water, that we might the better <lb/>know how much Water an&longs;wered in <lb/>weight to 3/4 of a Grain of Air, but not­<lb/>with&longs;tanding all the diligence that was <lb/>u&longs;ed to pre&longs;erve &longs;o brittle a Ve&longs;&longs;el, it <lb/>broke before we could perfect what we <lb/>were about, and we were not then pro­<lb/>vided of another Bubble fit for our <lb/>turn. </s></p><p type="main"> <s>The ha&longs;te I was in, My Lord, when I <lb/>&longs;ent away the la&longs;t Sheet, made me forget <lb/>to take notice to you of a Problem that <lb/>occurr'd to my thoughts, upon the oc­<lb/>ca&longs;ion of the &longs;low breaking of the Gla&longs;s <lb/>Bubble in our evacuated Receiver. </s> <s>For <lb/>it may &longs;eem &longs;trange, &longs;ince by our &longs;ixth <lb/>Experiment it appears, that the Air, when <lb/>permitted, will by its own internal Spring <lb/>expand it &longs;elfe twice as much as <emph type="italics"/>Mer­<lb/>&longs;ennus<emph.end type="italics"/> was able to expand it, by the <lb/>heat even of a candent <emph type="italics"/>Æolipile:<emph.end type="italics"/> Yet <lb/>the <emph type="italics"/>Elater<emph.end type="italics"/> of the Air was &longs;carce able to <lb/>break a very thin Gla&longs;s Bubble, and ut-<pb xlink:href="013/01/314.jpg" pagenum="284"/>terly unable to break one &longs;omewhat thic­<lb/>ker, within who&longs;e cavity it was impri­<lb/>&longs;on'd; whereas Air pent up and agitated <lb/>by heat is able to perform &longs;o much more <lb/>con&longs;iderable effects, that (not to mention <lb/>tho&longs;e of Rarefaction that are more obvi­<lb/>ous) the Learned Je&longs;uit <emph type="italics"/>Cabæus<emph.end type="italics"/> (he that <lb/><arrow.to.target n="marg45"/><lb/>writ of the Load-&longs;tone) relates, That he <lb/>&longs;aw a Marble Pillar (&longs;o va&longs;t, that three <lb/>men together with di&longs;play'd arms could <lb/>not imbrace it, and that 1000 Yoke of <lb/>Oxen drawing it &longs;everal ways with all <lb/>their &longs;trength, could not have torn it <lb/>a&longs;&longs;under) quite broken off in the mid&longs;t, <lb/>by rea&longs;on of &longs;ome Wood, which hap­<lb/>pening to be burnt ju&longs;t by the Pillar, the <lb/>heat proceeding from the neighboring <lb/>Fire, &longs;o rarified &longs;ome Air or Spirituous <lb/>Matter which was &longs;hut up in the cavities <lb/>of the Marble, that it broke through the <lb/>&longs;olid Body of the Stone to obtain room <lb/>to expand it &longs;elf. </s></p><p type="margin"> <s><margin.target id="marg45"/><emph type="italics"/><gap/>: Nicoi: <lb/>Cab: lib:<emph.end type="italics"/> 4. <lb/><emph type="italics"/>Meteo<gap/> A­<lb/><gap/><emph.end type="italics"/></s></p><p type="main"> <s>I remember I have taken notice that <lb/>probably the rea&longs;on why the included Air <lb/>did not break the hermetically &longs;eal'd Bub­<lb/>bles that remain'd intire in our emptyed <lb/>Receiver, was, That the Air, being &longs;ome­<lb/>what rarefied by the Flame imploy'd to <lb/>clo&longs;e the Gla&longs;s, its Spring, upon the re-<pb xlink:href="013/01/315.jpg" pagenum="285"/>ce&longs;s of the heat, grew weaker then before. <lb/></s> <s>But though we reject not that ghe&longs;s, yet <lb/>it will not in the pre&longs;ent ca&longs;e &longs;erve the <lb/>turn, becau&longs;e that much &longs;maller Gla&longs;s <lb/>bubbles exactly clo&longs;'d, will, by the in­<lb/>cluded Air (though agitated but by the <lb/>heat of a very moderate Fire) be made <lb/>to fly in pieces. </s> <s>Whether we may be <lb/>a&longs;&longs;i&longs;ted to &longs;alve this Problem, by con&longs;i­<lb/>dering that the heat does from within ve­<lb/>hemently agitate the Corpu&longs;cles of the <lb/>Air, and adde its a&longs;&longs;i&longs;tance to the Spring <lb/>they had before, I &longs;hall not now examine: <lb/>&longs;ince I here but propo&longs;e a Problem, and <lb/>that chiefly that by this memorable Story <lb/>of <emph type="italics"/>Cabæus,<emph.end type="italics"/> notice may be taken of the <lb/>prodigious power of Rarefaction, which <lb/>hereby appears capable of performing <lb/>&longs;tranger things then any of our Experi­<lb/>ments have hitherto a&longs;crib'd to it. </s></p><p type="main"> <s>We &longs;hould hence, My Lord, imme­<lb/>diatly proceed to the next Experiment, <lb/>but that we think it fit, on this occa&longs;ion, <lb/>to acquaint You with what &longs;ome former <lb/>tryals (though not made in our Engine) <lb/>have taught us, concerning what we <lb/>would have di&longs;cover'd by the newly <lb/>mention'd Bubble that broke. </s> <s>And this <lb/>the rather, becau&longs;e (a great part of this <pb xlink:href="013/01/316.jpg" pagenum="286"/>letter &longs;uppo&longs;ing the gravity of the Aire) <lb/>it will not be impertinent to determine <lb/>more particularly then hitherto we have <lb/>done, what gravity we a&longs;cribe to it. </s></p><p type="main"> <s>We tooke then an <emph type="italics"/>Æolipile<emph.end type="italics"/> made of <lb/>copper, weighing &longs;ix ounces, five drachms, <lb/>and eight and forty graines: this being <lb/>made as hot as we dur&longs;t make it, (for feare <lb/>of melting the mettle, or at lea&longs;t the So­<lb/>dar) was removed from the fire and im­<lb/>mediately &longs;topped with hard wax that no <lb/>Aire at all might get in at the little <lb/>hole wont to be left in <emph type="italics"/>Æolipiles<emph.end type="italics"/> for the <lb/>fumes to i&longs;&longs;ue out at: Then the <emph type="italics"/>Æolipile<emph.end type="italics"/><lb/>being &longs;uffer'd lea&longs;urely to coole was again <lb/>weighed together with the wax that &longs;topt <lb/>it, and was found to weigh (by rea&longs;on of <lb/>the additionall weight of the wax) &longs;ix <lb/>ounces, &longs;ixe drachmes, and 39 graines. <lb/></s> <s>La&longs;tly, the wax being perforated without <lb/>taking any of it out of the Scale, the <lb/>externall Aire was &longs;uffered to ru&longs;h in <lb/>(which it did with &longs;ome noy&longs;e) and then <lb/>the <emph type="italics"/>Æolipile<emph.end type="italics"/> and wax, being againe <lb/>weighed amounted to &longs;ix ounces, &longs;ix <lb/>drachmes, and 50. graines. </s> <s>So that the <lb/><emph type="italics"/>Æolipile<emph.end type="italics"/> freed as farre as our fire could <lb/>free it, from it's Aire, weighed le&longs;&longs;e then <pb xlink:href="013/01/317.jpg" pagenum="287"/>it &longs;elfe when repleni&longs;hed with Air, full <lb/>eleven graines. </s> <s>That is, the Air contain­<lb/>able within the cavity of the <emph type="italics"/>Æolipile<emph.end type="italics"/> a­<lb/>mounted to eleven graines and &longs;omewhat <lb/>more; I &longs;ay &longs;omewhat more, becau&longs;e of <lb/>the particles of the Air, that were not <lb/>driven by the fire out of the <emph type="italics"/>Æolipile.<emph.end type="italics"/><lb/>And by the way (if there be no mi&longs;take <lb/>in the ob&longs;ervations of the diligent <emph type="italics"/>Mer­<lb/>&longs;ennus<emph.end type="italics"/>) it may &longs;eeme &longs;trange that it &longs;hould <lb/>&longs;o much differ from 2. or 3. of ours; in <lb/>none of which we could rarifie the Air in <lb/>our Æ<emph type="italics"/>olipile<emph.end type="italics"/> (though made red hot almo&longs;t <lb/>all over, and &longs;o immediately plung'd into <lb/>cold water) to halfe that degree which he <lb/>mentions, namely to 70. times it's natu­<lb/>rall extent, unle&longs;&longs;e it were that the <emph type="italics"/>Æo­<lb/>lipile<emph.end type="italics"/> he imploy'd was able to &longs;u&longs;taine <lb/>a more vehement heat then ours (which <lb/>yet we kept in &longs;o great an one, that once <lb/>the &longs;oder melting, it fell a&longs;under into the <lb/>two Hemi&longs;pheres it con&longs;i&longs;ts of.) </s></p><p type="main"> <s>The fore-mentioned way of weighing <lb/>the Air by the help of an <emph type="italics"/>Æolipile,<emph.end type="italics"/> &longs;eems <lb/>&longs;omewhat more exact then that which <lb/><emph type="italics"/>Mer&longs;ennus<emph.end type="italics"/> u&longs;ed, In that in ours the <emph type="italics"/>Æoli­<lb/>pile<emph.end type="italics"/> was not weighed, till it was cold; <lb/>whereas in his, being weighed red hot, it <pb xlink:href="013/01/318.jpg" pagenum="288"/>&longs;ubject to loo&longs;e of it's &longs;nb&longs;tance in the <lb/>cooling, for (as we have el&longs;ewhere noted <lb/>on another occa&longs;ion) Copper heated red <lb/>hot is wont in the cooling to throw off <lb/>little thin &longs;cales in &longs;uch plenty, that having <lb/>purpo&longs;ely watcht a Copper <emph type="italics"/>Æolipile<emph.end type="italics"/> du­<lb/>ring its refrigeration, we have &longs;een the <lb/>place round about it almo&longs;t covered with <lb/>tho&longs;e little &longs;cales it had every way &longs;cat­<lb/>ter'd: which, however they amount not <lb/>to much, ought not to be over-looked, <lb/>when 'tis &longs;o light a body as Air, that is <lb/>to be weighed. </s> <s>We will not examine, <lb/>whether the Æ<emph type="italics"/>olipile<emph.end type="italics"/> in cooling may not <lb/>receive &longs;ome little increment of weight, <lb/>either from the vapid or &longs;aline Steames <lb/>that wander up and downe in the Air: But <lb/>we will rather mention, that (for the grea­<lb/>ter exactne&longs;&longs;e) we imployed to weigh our <lb/><emph type="italics"/>Æolipile,<emph.end type="italics"/> both when fill'd onely with Air <lb/>and when repleni&longs;ht with Water, a paire <lb/>of &longs;cales that would turne (as they &longs;peak) <lb/>with the fourth part of a grain. </s></p><p type="main"> <s>As to the proportion of weight be­<lb/>twixt Air and Water, &longs;ome learned men <lb/>have attempted it by wayes &longs;o unaccurate <lb/>that they &longs;eeme to have much mi&longs;taken <lb/>it. </s> <s>For (not to mention the improbable <lb/>accounts of <emph type="italics"/>Kepler<emph.end type="italics"/> and others.) <!--neuer Satz-->The lear-<pb xlink:href="013/01/319.jpg" pagenum="289"/>ned and diligent <emph type="italics"/>Ricciolus,<emph.end type="italics"/> having pur­<lb/>po&longs;ely endeavoured to inve&longs;tigate this <lb/>proportion by meanes of a thin blad­<lb/>der, e&longs;timates the weight of the Air to <lb/>that of the Water to be as one to ten <lb/>thou&longs;and, or thereabouts. </s> <s>And indeed I re­<lb/>member that having formerly, on a cer­<lb/>tain occa&longs;ion, weighed a large bladder full <lb/>of Air, and found it when the Air was all <lb/>&longs;quee&longs;ed out, to have contained fourteen <lb/>graines of Air. </s> <s>I found the &longs;ame bladder <lb/>afterwards fill'd with water to containe <lb/>very neer 14. pound of that liquor: accor­<lb/>ding to which account, the proportion of <lb/>Air to Water was almo&longs;t as a graine to a <lb/>pound, that is, as one to above 7600. To <lb/>this we may adde, that on the other &longs;ide, <lb/><emph type="italics"/>Galileo<emph.end type="italics"/> him&longs;elfe u&longs;ing another, but an un­<lb/>accurate way too, defined the Air to be <lb/>in weight to Water, but as one to 4. hun­<lb/>dred. </s> <s>But the way formerly propo&longs;ed of <lb/>weighing the Air by an Æ<emph type="italics"/>olipile,<emph.end type="italics"/> &longs;eemes <lb/>by great oddes more exact; and (as farre <lb/>as we could ghe&longs;&longs;e) &longs;eemed to agree well <lb/>enough with the experiment made in our <lb/>Receiver. </s> <s>Wherefore it will be be&longs;t to <lb/>tru&longs;t our Æ<emph type="italics"/>olipile<emph.end type="italics"/> in the enquiry we are a­<lb/>bout, and according to our ob&longs;ervations <lb/>the water it contained amounting to one <pb xlink:href="013/01/320.jpg" pagenum="290"/>and twenty ounces and an halfe, and as <lb/>much Air as was requi&longs;ite to fill it weigh­<lb/>ing eleven graines, the proportion in gra­<lb/>vity of Air to Water of the &longs;ame bulk <lb/>will be as one to 938. And though we <lb/>could not fill the Æ<emph type="italics"/>olipile<emph.end type="italics"/> with water, &longs;o <lb/>exactly as we would, yet in regard we <lb/>could not either as perfectly as we would, <lb/>drive the Air out of it by heat; we think <lb/>the proportion may well enough hold: <lb/>but tho&longs;e that are delighted with round <lb/>numbers (as the phra&longs;e is) will not be <lb/>much mi&longs;taken if they reckon water to be <lb/>neere a thou&longs;and times heavier than Air. <lb/></s> <s>And (for further proof that we have made <lb/>the proportion betwixt the&longs;e two bodies <lb/>rather greater then le&longs;&longs;er then indeed it is; <lb/>and al&longs;o to confirme our former ob&longs;erva­<lb/>tion of the weight of the Air) we will adde, <lb/>That, having another time put &longs;ome Wa­<lb/>ter into the Æ<emph type="italics"/>olipile<emph.end type="italics"/> before we &longs;et it on <lb/>the fire, that the copious vapours of the <lb/>rarefied liquor might the better drive out <lb/>the Air, we found, upon try all carefully <lb/>made, that when the Æ<emph type="italics"/>olipile<emph.end type="italics"/> was refrige­<lb/>rated, and the included vapours were by <lb/>the cold turned againe into water (which <lb/>could not have happen'd to the Air, that <lb/>the preceeding Steams expell'd) the Air, <pb xlink:href="013/01/321.jpg" pagenum="291"/>when it was let in, increa&longs;'d the weight of <lb/>the <emph type="italics"/>Æolipile<emph.end type="italics"/> as much as before, namely, <lb/>Eleven Grains; though there were alrea­<lb/>dy in it twelve Drachmes and a half, be­<lb/>&longs;ides a couple of Grains of Water, which <lb/>remain'd of that we had formerly put in­<lb/>to it to drive out the Air. </s></p><p type="main"> <s><emph type="italics"/>Mer&longs;ennus<emph.end type="italics"/> indeed tells us, that by his <lb/>account Air is in weight to Water, as 1 to <lb/>1356. And adds, that we may, without <lb/>any danger, believe that the gravity of <lb/>Water to that of Air of a like bulk, is <lb/>not le&longs;s then of 1300 to 1. And con&longs;e­<lb/>quently, that the quantity of Air to a <lb/>quantity of Water equiponderant there­<lb/>to, is as 1300 to 1. But why we &longs;hould <lb/>relinqui&longs;h our own carefully repeated try­<lb/>als, I &longs;ee not. </s> <s>Yet I am unwilling to re­<lb/>ject tho&longs;e of &longs;o accurate and u&longs;eful a Wri­<lb/>ter: And therefore &longs;hall propo&longs;e a way <lb/>of reconciling our differing Ob&longs;ervations, <lb/>by pre&longs;enting, that the di&longs;crepance be­<lb/>tween them may probably ari&longs;e from the <lb/>differing con&longs;i&longs;tence of the Air at <emph type="italics"/>London<emph.end type="italics"/><lb/>and at <emph type="italics"/>Paris:<emph.end type="italics"/> For our Air being more cold <lb/>and moi&longs;t, then that which Your Lord­<lb/>&longs;hip now breaths, may be &longs;uppo&longs;'d al&longs;o <lb/>to be a fourth or fifth part more heavy. </s> <s>I <lb/>leave it to be con&longs;ider'd, whether it be of <pb xlink:href="013/01/322.jpg" pagenum="292"/>any moment that our Ob&longs;ervations were <lb/>made in the mid&longs;t of Winter, whereas his <lb/>were perhaps made in &longs;ome warmer time <lb/>of the Year. </s> <s>But I think it were not a­<lb/>mi&longs;s that, by the method formerly pro­<lb/>po&longs;'d, the gravity of the Air were ob­<lb/>&longs;erv'd both in &longs;everal Countries, and in <lb/>the &longs;ame Country, in the &longs;everal Sea&longs;ons <lb/>of the Year and differing Temperatures of <lb/>the Weather. </s> <s>And I would give &longs;ome­<lb/>thing of value to know the weight of &longs;uch <lb/>an <emph type="italics"/>Æolipile<emph.end type="italics"/> as ours full of air in the mid&longs;t <lb/>of Winter in <emph type="italics"/>Nova Zembla,<emph.end type="italics"/> if that be <lb/>true which we formerly took notice of, <lb/>namely, That the <emph type="italics"/>Hollanders,<emph.end type="italics"/> who Win­<lb/>tered there, found that Air &longs;o thick that <lb/>their Clock would not go. </s></p><p type="main"> <s>If Your Lord&longs;hip &longs;hould now ask me, <lb/>if I could not by the help of the&longs;e, and <lb/>our other Ob&longs;ervations, decide the Con­<lb/>trover&longs;ies of our Modern Mathematici­<lb/>ans about the height of the Air or Atmo­<lb/>&longs;phere, by determining how high it doth <lb/>indeed reach: I &longs;hould an&longs;wer, That <lb/>though it &longs;eems ea&longs;ie enough to &longs;hew that <lb/>divers Famous and Applauded Writers <lb/>have been mi&longs;taken in a&longs;&longs;igning the heigth <lb/>of the Atmo&longs;phere: Yet it &longs;eems very <lb/>difficult preci&longs;ely to define of what height <pb xlink:href="013/01/323.jpg" pagenum="293"/>it is. </s> <s>And becau&longs;e we have hitherto but <lb/>lightly touch'd upon a matter of &longs;uch im­<lb/>portance, we pre&longs;ume it wil not be thought <lb/>impertinent, upon this occa&longs;ion, to annex <lb/>&longs;omething towards the Elucidation of <lb/>it. </s></p><p type="main"> <s>What we have already try'd and newly <lb/>&longs;et down, allows us to take it for granted, <lb/>that (at lea&longs;t about <emph type="italics"/>London<emph.end type="italics"/>) the propor­<lb/>tion of gravity betwixt Water and Air, <lb/>of equal bulk, is as of a thou&longs;and to <lb/>one. </s></p><p type="main"> <s>The next thing therefore that we are <lb/>to enquire after, in order to our pre&longs;ent <lb/>de&longs;ign, is the difference in weight betwixt <lb/>Water and Quick-&longs;ilver: And though <lb/>this hath been defin'd already by the Il­<lb/>lu&longs;trious <emph type="italics"/>Verulam,<emph.end type="italics"/> and &longs;ome other inqui­<lb/>&longs;itive Per&longs;ons, that have compar'd the <lb/>weight of &longs;everal Bodies, and ca&longs;t their <lb/>Ob&longs;ervations into Tables, yet we &longs;hall <lb/>not &longs;cruple to annex our own tryals about <lb/>it: Partly, becau&longs;e we finde Authors <lb/>con&longs;iderably to di&longs;-agree; partly, becau&longs;e <lb/>we u&longs;'d exacter Scales, and a &longs;omewhat <lb/>more wary method then others &longs;eem to <lb/>have done: And partly al&longs;o, becau&longs;e ha­<lb/>ving pro&longs;ecuted our inquiry by two or <lb/>three &longs;everal ways; the &longs;mall difference <pb xlink:href="013/01/324.jpg" pagenum="294"/>between the events may a&longs;&longs;ure us that we <lb/>were not much mi&longs;taken. </s></p><p type="main"> <s>We took then a Gla&longs;s Pipe, of the <lb/>form of an inverted <emph type="italics"/>Siphon,<emph.end type="italics"/> who&longs;e &longs;hape <lb/>is delineated in the &longs;ixteenth Figure: And <lb/>pouring into it a quantity of Quick &longs;ilver, <lb/>we held it &longs;o, that the &longs;uperficies of the <lb/>Liquor, both in the longer and &longs;horter <lb/>leg, lay in a Horizontal Line, denoted in <lb/>the Scheme by the prick'd Line EF; then <lb/>pouring Water into the longer Leg of the <lb/><emph type="italics"/>Siphon,<emph.end type="italics"/> till that was almo&longs;t fill'd, we ob­<lb/>&longs;erv'd the &longs;urface of the Quick-&longs;ilver in <lb/>that leg to be, by the weight of the Wa­<lb/>ter, depre&longs;&longs;'d, as from E to B; and in <lb/>the &longs;horter leg, to be as much impell'd <lb/>upward as from F to G: Whereupon ha­<lb/>ving formerly &longs;tuck marks, as well at the <lb/>point B, as at the oppo&longs;ite point D, we <lb/>mealur d both the di&longs;tance DC to have <lb/>the height of the Cylinder of Quick-&longs;il­<lb/>ver, which was rai&longs;'d above the Point D <lb/>(level with the &longs;urface of the Quick-&longs;ilver <lb/>in the other leg) by the weight of the Wa­<lb/>ter, and the di&longs;tance BA which gave us <lb/>the height of the Cylinder of Water. </s> <s>So <lb/>that the di&longs;tance DC amounting to (2 12/54) <lb/>Inches, and the height of the Water a­<lb/>mounting (30 45/50) Inches; and the whole <pb xlink:href="013/01/325.jpg" pagenum="295"/>numbers on both &longs;ides, which the annex­<lb/>ed Fractions being reduc'd to improper <lb/>Fractions of the &longs;ame denomination, the <lb/>proportion appear'd to be (the denomi­<lb/>nators beng left out as equal on both &longs;ides) <lb/>as 121 to 1665; or by reduction, as one <lb/>to (13 92/121). </s></p><p type="main"> <s>Be&longs;ides this unu&longs;ual way of determi­<lb/>ning the gravity of &longs;ome things, we mea­<lb/>&longs;ur'd the proportion betwixt Quick-&longs;ilver <lb/>and Water, by the help of &longs;o exact a bal­<lb/>lance, as loo&longs;es its <emph type="italics"/>Æquilibrium<emph.end type="italics"/> by the <lb/>hundredth part of a Grain. </s> <s>But becau&longs;e <lb/>there is wont to be committed an over­<lb/>&longs;ight in weighing Quick-&longs;ilver and Wa­<lb/>ter, e&longs;pecially if the Orifice of the Ve&longs;&longs;el <lb/>wherein they are put be any thing wide, in <lb/>regard that men heed not that the &longs;urface <lb/>of Water in Ve&longs;&longs;els will be concave, <lb/>but that of Quick-&longs;ilver, notably convex <lb/>or protuberant: To avoid this u&longs;ual over­<lb/>&longs;ight (I &longs;ay) we made u&longs;e of a gla&longs;s bubble, <lb/>blown very thin at the Flame of a Lamp, <lb/>that it might not be too heavy for the <lb/>Ballance, and terminating in a very &longs;lender <lb/>neck, wherein the concavity or convexity <lb/>of a Liquor could not be con&longs;iderable: <lb/>This Gla&longs;s weighing 23 1/2 Grains, we fill'd <pb xlink:href="013/01/326.jpg" pagenum="296"/>almo&longs;t with Quick-&longs;ilver, and fa&longs;tning a <lb/>mark over again&longs;t the middle of the pro­<lb/>tuberant Superficies as near as our Eyes <lb/>could judge, we found that the Quick­<lb/>&longs;ilver alone weighed 299 1/32 Grains: Then <lb/>the Quick-&longs;ilver being pour'd out, and <lb/>the &longs;ame Gla&longs;s being fill'd as full of com­<lb/>mon Water, we found the Liquor to <lb/>weigh 21 7/8 Grains. </s> <s>Whereby it appear'd <lb/>that the weight of Water to Quick­<lb/>&longs;ilver, is as one to (13 19/28): Though our Il­<lb/>lu&longs;trious <emph type="italics"/>Verulam<emph.end type="italics"/> (que&longs;tionle&longs;s not for <lb/>want of Judgement or Care, but of ex­<lb/>act In&longs;truments) makes the proportion <lb/>betwixt tho&longs;e two Liquors to be greater <lb/>then of 1 to 17. And to adde, that up­<lb/>on the by, &longs;ince Quick-&longs;ilver and well <lb/>rectified Spirit of Wine, are (how ju&longs;tly <lb/>I &longs;ay not) accounted, the one the hea­<lb/>vie&longs;t, and the other the lighte&longs;t of Li­<lb/>quors; we thought to fill in the &longs;ame <lb/>Gla&longs;s, and with the &longs;ame Scales to ob­<lb/>&longs;erve the difference betwixt them, which <lb/>we found to be as of 1 to (16 641/1084); where­<lb/>by it appear'd, That the difference be­<lb/>twixt Spirit of Wine, that may be made <lb/>to burn all away, (&longs;uch as was ours) and <lb/>common Water, is as betwixt 1 and (1 44/171) </s></p><pb xlink:href="013/01/327.jpg" pagenum="297"/><p type="main"> <s>We might here take occa&longs;ion to ad­<lb/>mire, that though Water (as appear'd by <lb/>the Experiment formerly mention'd of <lb/>the Pewter Ve&longs;&longs;el) &longs;eems not capable of <lb/>any con&longs;iderable conden&longs;ation, and &longs;eems <lb/>not to have inter&longs;per&longs;'d in it any &longs;tore of <lb/>Air; yet Quick-&longs;ilver, of no greater bulk <lb/>then Water, &longs;hould weigh near fourteen <lb/>times as much. </s> <s>But having onely point­<lb/>ed at this as a thing worthy of con&longs;idera­<lb/>tion, we will proceed in our inquiry after <lb/>the heigth of the Atmo&longs;phere: And to <lb/>avoid the trouble of Fractions, we will <lb/>a&longs;&longs;ume that Quick-&longs;ilver is fourteen times <lb/>as heavy as Water, &longs;ince it wants &longs;o little <lb/>of being &longs;o. </s></p><p type="main"> <s>Wherefore having now given us the <lb/>proportion of Air to Water, and Water <lb/>to Quick-&longs;ilver, it will be very ea&longs;ie to <lb/>finde the proportion betwixt Air and <lb/>Quick-&longs;ilver, in ca&longs;e we will &longs;uppo&longs;e the <lb/>Atmo&longs;phere to be uniformly of &longs;uch a <lb/>con&longs;i&longs;tence as the Air we weighed here <lb/>below. </s> <s>For &longs;ince our Engine hath &longs;uffi­<lb/><arrow.to.target n="marg46"/><lb/>ciently manife&longs;ted that 'tis the <emph type="italics"/>Æquili­<lb/>brium<emph.end type="italics"/> with the external Air, that in the <lb/><emph type="italics"/>Torricellian<emph.end type="italics"/> Experiment keeps the Quick­<lb/>&longs;ilver from &longs;ub&longs;iding; And &longs;ince, by our <lb/>accurate Experiment formerly mention'd, <pb xlink:href="013/01/328.jpg" pagenum="298"/>it appears that a Cylinder of Mercury, <lb/>able to ballance a Cylinder of the whole <lb/>Atmo&longs;phere, amounted to near about <lb/>thirty Inches; and &longs;ince, con&longs;equently <lb/>we may a&longs;&longs;ume the proportion of Quick­<lb/>&longs;ilver to Air to be as fourteen thou&longs;and to <lb/>one; it will follow, that a Cylinder of <lb/>Air, capable to maintain an <emph type="italics"/>Æquilibrium,<emph.end type="italics"/><lb/>with a Mercurial Cylinder of two Foot <lb/>and an half in height, mu&longs;t amount to <lb/>35000 Feet of our Engli&longs;h Mea&longs;ure; <lb/>and con&longs;equently (reckoning five Foot <lb/>to a Geometrical Pace, and one thou&longs;and <lb/>&longs;uch Paces to a Mile) to &longs;even full <lb/>Miles. </s></p><p type="margin"> <s><margin.target id="marg46"/><gap/></s></p><p type="main"> <s>But this (as we lately intimated) pro­<lb/>ceeds upon the &longs;uppo&longs;ition, that the Air <lb/>is every where of the &longs;ame con&longs;i&longs;tence <lb/>that we found it near the &longs;urface of the <lb/>Earth; but that cannot with any &longs;afety <lb/>be concluded, not onely for the rea&longs;on I <lb/>finde to have been taken notice of by the <lb/>Antients, and thus expre&longs;t in <emph type="italics"/>Seneca: <lb/>Omnis Aër<emph.end type="italics"/> (&longs;ays he) <emph type="italics"/>quo propior e&longs;t terris<emph.end type="italics"/><lb/><arrow.to.target n="marg47"/><lb/><emph type="italics"/>hoc cra&longs;sior; quemadmodum in aqua & in <lb/>omni humore fæx ima e&longs;t, it a in Aëre &longs;pi&longs;­<lb/>&longs;ißima quæ&queacute; de&longs;idunt;<emph.end type="italics"/> but much more, <lb/>becau&longs;e the &longs;pringy Texture of the Aërial <lb/>Corpu&longs;cles, makes them capable of a <pb xlink:href="013/01/329.jpg" pagenum="299"/>very great compre&longs;&longs;ion, which the weight <lb/>of the incumbent part of the Atmo­<lb/>&longs;phere is very &longs;ufficient to give tho&longs;e that <lb/>be undermo&longs;t and near the &longs;urface of the <lb/>Earth. </s> <s>And if we recall to minde tho&longs;e <lb/>former Experiments, whereby we have <lb/>manife&longs;ted, That Air, much rarefied with­<lb/>out heat, may ea&longs;ily admit a further ra­<lb/>refaction from heat; and that the Air, even <lb/>without being expanded by heat, is capa­<lb/>ble of being rarefied to above one hundred <lb/>and fifty times the extent it u&longs;ually po&longs;­<lb/>&longs;e&longs;&longs;es here below; How can it be demon­<lb/>&longs;trated that the Atmo&longs;phere may not, for <lb/>ought we know, or at lea&longs;t for ought can <lb/>be determin'd by our Statical and Mecha­<lb/>nical Experiments, ri&longs;e to the height of <lb/>Five and twenty <emph type="italics"/>German<emph.end type="italics"/> Leagues, if not <lb/>of &longs;ome hundred of common Miles? </s></p><p type="margin"> <s><margin.target id="marg47"/><gap/> 4. <lb/><gap/> 10.</s></p><p type="main"> <s>And this conjecture it &longs;elf may appear <lb/>very injurious to the height whereunto <lb/>Exhalations may a&longs;cend, if we will allow <lb/><arrow.to.target n="marg48"/><lb/>that there was no mi&longs;take in that &longs;trange <lb/>Ob&longs;ervation made at <emph type="italics"/>Tolous<emph.end type="italics"/> in a clear <lb/>Night in <emph type="italics"/>Augu&longs;t,<emph.end type="italics"/> by the diligent Ma­<lb/>thematician <emph type="italics"/>Emanuel Magnan,<emph.end type="italics"/> and thus <lb/>Recorded by <emph type="italics"/>Ricciolus,<emph.end type="italics"/> (for I have not at <lb/>hand the Authors own Book) <emph type="italics"/>Vidit<emph.end type="italics"/> (&longs;ays <lb/>he) <emph type="italics"/>ab hor a undecima po&longs;t meridiem u&longs;&queacute; ad<emph.end type="italics"/><pb xlink:href="013/01/330.jpg" pagenum="300"/><emph type="italics"/>mediam noctem Lunâ infra horizontem <lb/>po&longs;itâ, nubeculam quandam lucidam prope <lb/>Meridianum fere u&longs;que ad Zenith diffu&longs;am <lb/>quæ con&longs;ider at is omnibus non poter at ni&longs;i à <lb/>&longs;ole illuminari; ideoque altior e&longs;&longs;e debuit <lb/>tota umbr a terræ. </s> <s>Addit<emph.end type="italics"/> (continues <emph type="italics"/>Ricci­<lb/>olus) &longs;imile quid eveni&longs;&longs;e Michaeli Angelo <lb/>Riccio apud Sabinos ver&longs;anti nempe viro <lb/>in Mathe&longs;i eruditi&longs;simo.<emph.end type="italics"/></s></p><p type="margin"> <s><margin.target id="marg48"/><gap/></s></p><p type="main"> <s>Various Ob&longs;ervations made at the <lb/>feet, tops, and interjacent parts of high <lb/>Mountains, might perchance &longs;omewhat <lb/>a&longs;&longs;i&longs;t us to make an e&longs;timate in what pro­<lb/>portion, if in any certain one, the higher <lb/>Air is thicker then the lower, and ghe&longs;s <lb/>at the di&longs;-form con&longs;i&longs;tence, as to laxity <lb/>and compactne&longs;s of the Air at &longs;everal <lb/>di&longs;tances from us. </s> <s>And if the difficul­<lb/>ties about the refractions of the Cele&longs;tial <lb/>Lights, were &longs;atisfactorily determin'd, <lb/>that might al&longs;o much conduce to the pla­<lb/>cing due limits to the Atmo&longs;phere (who&longs;e <lb/>Dimen&longs;ions tho&longs;e Ob&longs;ervations about <lb/>Refractions &longs;eem hitherto much to con­<lb/>tract.) But for the pre&longs;ent we dare not <lb/>pronounce any thing peremptorily con­<lb/>cerning the height of it, but leave it to <lb/>further inquiry: contenting our &longs;elves to <lb/>have manife&longs;ted the mi&longs;take of divers <pb xlink:href="013/01/331.jpg" pagenum="301"/>eminent Modern Writers, who will not <lb/>allow the Atmo&longs;phere to exceed above <lb/>two or three Miles in height (as the Fa­<lb/>mous K<emph type="italics"/>epler<emph.end type="italics"/> will not the <emph type="italics"/>Aër refractivus<emph.end type="italics"/>) <lb/>and to have rendred a rea&longs;on why in the <lb/>mention we made in the Notes upon the <lb/>fir&longs;t Experiment, touching the height of <lb/>the Atmo&longs;phere, we &longs;crupled not to &longs;peak <lb/>of it, as if it might be many Miles high. </s></p><p type="main"> <s>WE will now proceed to recite a <lb/><arrow.to.target n="marg49"/><lb/><emph type="italics"/>Phænomenon,<emph.end type="italics"/> which, though <lb/>made among&longs;t the fir&longs;t, we thought fit <lb/>not to mention till after many others, that <lb/>we might have the opportunity to ob­<lb/>&longs;erve as many Circum&longs;tances of it as we <lb/>could, and &longs;o pre&longs;ent Your Lord&longs;hip at <lb/>once, mo&longs;t of what we at &longs;everal times <lb/>have taken notice of concerning &longs;o odde <lb/>a <emph type="italics"/>Phænomenon.<emph.end type="italics"/></s></p><p type="margin"> <s><margin.target id="marg49"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 37.</s></p><p type="main"> <s>Our Engine had not been long fini&longs;h'd, <lb/>when, at the fir&longs;t lea&longs;ure we could &longs;teal <lb/>from our occa&longs;ions to make tryal of it, <lb/>we cau&longs;'d the Air to be pump'd out of <lb/>the Receiver; and whil'&longs;t I was bu&longs;ied in <lb/>entertaining a Learned Friend that ju&longs;t <lb/>then came to vi&longs;it me, an Ingenious By-<pb xlink:href="013/01/332.jpg" pagenum="302"/>&longs;tander, thought he perceiv'd &longs;ome new <lb/>kind of Light in the Receiver, of which <lb/>giving me ha&longs;tily notice, my Friend and <lb/>I pre&longs;ently ob&longs;erv'd, that when the Suc­<lb/>ker was drawn down, immediately upon <lb/>the turning of the Key, there appear'd <lb/>a kinde of Light in the Receiver, almo&longs;t <lb/>like a faint fla&longs;h of Lightening in the <lb/>Day-time, and almo&longs;t as &longs;uddenly did it <lb/>appear and vani&longs;h. </s> <s>Having, not with­<lb/>out &longs;ome amazement, ob&longs;erv'd divers <lb/>of the&longs;e Apparitions of Light, we took <lb/>notice that the Day was clear, the hour <lb/>about ten in the Morning, that the onely <lb/>Window in the Room fac'd the North; <lb/>and al&longs;o, that by interpo&longs;ing a Cloak, or <lb/>any opacous Body between the Receiver <lb/>and the Window, though the re&longs;t of the <lb/>Room were &longs;ufficiently enlightned, yet <lb/>the fla&longs;hes did not appear as before, un­<lb/>le&longs;s the opacous Body were remov'd. <lb/></s> <s>But not being able on all the&longs;e Circum­<lb/>&longs;tances to ground any firm Conjecture <lb/>at the cau&longs;e of this &longs;urpri&longs;ing <emph type="italics"/>Phænome­<lb/>non,<emph.end type="italics"/> as &longs;oon as Night was come, we <lb/>made the Room very dark; and plying <lb/>the Pump, as in the Morning, we could <lb/>not, though we often try'd, find, upon <lb/>the turning of the Key, &longs;o much as the <pb xlink:href="013/01/333.jpg" pagenum="303"/>lea&longs;t glimmering of Light; whence we <lb/>inferr'd, that the fla&longs;h appearing in the <lb/>Receiver, did not proceed from any new <lb/>Light generated there, but from &longs;ome <lb/>reflections of the light of the Sun, or <lb/>other Luminous Bodies plac'd without <lb/>it; though whence that Reflection <lb/>&longs;hould proceed, it po&longs;'d us to conje­<lb/>cture. </s></p><p type="main"> <s>Wherefore the next Morning, ho­<lb/>ping to inform our &longs;elves better, we <lb/>went about to repeat the Experiment, <lb/>but though we could as well as former­<lb/>ly exhau&longs;t the Receiver, though the <lb/>place wherein we made the tryal was the <lb/>very &longs;ame; and though other Circum­<lb/>&longs;tances were re&longs;embling, yet we could <lb/>not di&longs;cover the lea&longs;t appearance of <lb/>Light all that Day, nor on divers o­<lb/>thers on which tryal was again fruitle&longs;­<lb/>ly made; nor can we to this very time <lb/>be &longs;ure a Day before hand that the&longs;e <lb/>Fla&longs;hes will be to be &longs;een in our great <lb/>Receiver. </s> <s>Nay, having once found the <lb/>Engine in a good humour (if I may <lb/>&longs;o &longs;peak) to &longs;hew this trick, and &longs;ent <lb/>notice of it to our Learned Friend <lb/>Doctor <emph type="italics"/>Wallis,<emph.end type="italics"/> who expre&longs;&longs;'d a great <pb xlink:href="013/01/334.jpg" pagenum="304"/>de&longs;ire to &longs;ee this <emph type="italics"/>Phænomenon,<emph.end type="italics"/> though he <lb/>were not then above a Bow-&longs;hoot off, and <lb/>made ha&longs;te to &longs;atisfie his Curio&longs;ity; yet <lb/>by that time he was come, the thing he <lb/>came for was no longer to be &longs;een; &longs;o <lb/>that having vainly endeavored to exhibit <lb/>again the <emph type="italics"/>Phænomenon<emph.end type="italics"/> in his pre&longs;ence, I <lb/>began to apprehend what he might think <lb/>of me, when unexpectedly the Engine <lb/>pre&longs;ented us a fla&longs;h, and after that a &longs;econd, <lb/>and as many more, as &longs;uffic'd to &longs;atisfie <lb/>him that we might very well confidently <lb/>relate, that we have our &longs;elves &longs;een this <lb/><emph type="italics"/>Phænomenon,<emph.end type="italics"/> though not confidently pro­<lb/>mi&longs;e to &longs;hew it others. </s></p><p type="main"> <s>And this un&longs;ucce&longs;sfulne&longs;s whereto our <lb/>Experiment is lyable, being &longs;uch, that by <lb/>all our watchfulne&longs;s and tryals, we could <lb/>never reduce it to any certain Rules or <lb/>Ob&longs;ervations; &longs;ince in all con&longs;titutions <lb/>of the Weather, times of the Day, <emph type="italics"/>&c.<emph.end type="italics"/><lb/>it will &longs;ometimes an&longs;wer, and &longs;ometimes <lb/>di&longs;-appoint our Expectations; We are <lb/>much di&longs;courag'd from venturing to frame <lb/>an <emph type="italics"/>Hypothe&longs;is<emph.end type="italics"/> to give an account of it: <lb/>which if the Experiment did con&longs;tantly <lb/>&longs;ucceed, might the more hopefully be at­<lb/>tempted; by the help of the following <lb/><emph type="italics"/>Phænomena<emph.end type="italics"/> laid together: &longs;ome of them <pb xlink:href="013/01/335.jpg" pagenum="305"/>produc'd upon tryals purpo&longs;ely made <lb/>to examine the validity of the conjectures, <lb/>other tryals had &longs;ugge&longs;ted. </s></p><p type="main"> <s>Fir&longs;t then we ob&longs;erv'd, that the Appa­<lb/>rition of Light may be made as well by <lb/>Candle-light, as by Day-light; and in <lb/>whatever po&longs;ition the Candle be held, in <lb/>reference to the Receiver, as on this or <lb/>that hand of it, above it, beneath it, or <lb/>any other way, provided the Beams of <lb/>Light be not hinder'd from falling upon <lb/>the Ve&longs;&longs;el. </s></p><p type="main"> <s>Next, we noted that the fla&longs;h appears <lb/>immediately upon the turning of the <lb/>Key, to let the Air out of the Receiver <lb/>into the empty'd Cylinder, in &longs;o much <lb/>that I remember not that when at any <lb/>time in our great Receiver, the Stop-cock <lb/>was open'd before the Cylinder was ex­<lb/>hau&longs;ted (whereby it came to pa&longs;s that the <lb/>Air did rather de&longs;cend, then ru&longs;h into the <lb/>Cylinder) the often mention'd fla&longs;h ap­<lb/>pear'd to our eyes. </s></p><p type="main"> <s>Yet, we further ob&longs;erv'd, that when in­<lb/>&longs;tead of the great Receiver we made u&longs;e <lb/>of a &longs;mall Gla&longs;s, not containing above a <lb/>pound and a half of Water, the <emph type="italics"/>Phæno­<lb/>menon<emph.end type="italics"/> might be exhibited though the <lb/>Stop-cock were open, provided the <pb xlink:href="013/01/336.jpg" pagenum="306"/>Sucker were drawn nimbly down. </s></p><p type="main"> <s>We noted too, that when we began to <lb/>empty the Receiver, the appearances of <lb/>Light were much more con&longs;picuous <lb/>then towards the latter end, when little <lb/>Air at a time could pa&longs;s out of the Re­<lb/>ceiver. </s></p><p type="main"> <s>We ob&longs;erv'd al&longs;o, that when the Suc­<lb/>ker had not been long before well Oyl'd, <lb/>and in&longs;tead of the great Receiver, the <lb/>&longs;maller Ve&longs;&longs;el above-mention'd was em­<lb/>ploy'd; We ob&longs;erv'd, I &longs;ay, that then, <lb/>upon the opening of the Stop-cock, as <lb/>the Air de&longs;cended out of the Gla&longs;s in­<lb/>to the empty'd Cylinder, &longs;o at the &longs;ame <lb/>time there a&longs;cended out of the Cylinder <lb/>into the Ve&longs;&longs;el a certain Steam, which <lb/>&longs;eem'd to con&longs;i&longs;t of very little Bubbles, <lb/>or other minute Corpu&longs;cles thrown up <lb/>from the Oyl, rarefied by the attrition it <lb/>&longs;uffered in the Cylinder. </s> <s>For at the <lb/>&longs;ame time that the&longs;e Steams a&longs;cended <lb/>into the Gla&longs;s, &longs;ome of the &longs;ame kinde <lb/>manife&longs;tly i&longs;&longs;ued out like a little Pillar of <lb/>Smoke at the Orifice of the Valve, when <lb/>that was occa&longs;ionally open'd. </s> <s>And the&longs;e <lb/>Steams frequently enough pre&longs;enting <lb/>them&longs;elves to our view, we found, by <lb/>expo&longs;ing the Gla&longs;s to a clear Light, that <pb xlink:href="013/01/337.jpg" pagenum="307"/>they were wont to play up and down <lb/>in it, and &longs;o by their whitei&longs;hne&longs;s, to e­<lb/>mulate in &longs;ome mea&longs;ure the apparition of <lb/>Light. </s></p><p type="main"> <s>For we likewi&longs;e &longs;ometimes found, by <lb/>watchful ob&longs;ervation, that when the <lb/>Fla&longs;h was great, not onely at the very <lb/>in&longs;tant the Receiver lo&longs;t of its tran&longs;pa­<lb/>rency, by appearing full of &longs;ome kinde <lb/>of whiti&longs;h &longs;ub&longs;tance; but that for &longs;ome <lb/>&longs;hort time after the &longs;ides of the Gla&longs;s <lb/>continued &longs;omewhat opacous, and <lb/>&longs;eem'd to be darken'd, as if &longs;ome <lb/>whiti&longs;h Steam adher'd to the in&longs;ide of <lb/>them. </s></p><p type="main"> <s>He that would render a Rea&longs;on of <lb/>the <emph type="italics"/>Phænomenon,<emph.end type="italics"/> whereof all the&longs;e are <lb/>not all the Circum&longs;tances, mu&longs;t doe <lb/>two things; whereof the one is diffi­<lb/>cult, and the other little le&longs;s then im­<lb/>po&longs;&longs;ible: For he mu&longs;t give an Ac­<lb/>count not onely whence the appearing <lb/>whitene&longs;s proceeds, but wherefore that <lb/>whitene&longs;s does &longs;ometimes appear and <lb/>&longs;ometimes not. </s></p><p type="main"> <s>For our part, we freely confe&longs;&longs;e <lb/>our &longs;elves at a lo&longs;&longs;e about rendering <pb xlink:href="013/01/338.jpg" pagenum="308"/>a Rea&longs;on of the le&longs;s difficult part of the <lb/>Problem: And though Your Lord­<lb/>&longs;hip &longs;hould ev'n pre&longs;s us to declare what <lb/>Conjecture it was, that the above-recited <lb/>Circum&longs;tances &longs;ugge&longs;ted to us, we &longs;hould <lb/>propo&longs;e the thoughts we then had, no o­<lb/>therwi&longs;e then as bare Conjectures. </s></p><p type="main"> <s>In ca&longs;e then our <emph type="italics"/>Phænomenon<emph.end type="italics"/> had con­<lb/>&longs;tantly and uniformly appear'd, we &longs;hould <lb/>have &longs;u&longs;pected it to have been produc'd <lb/>after &longs;ome &longs;uch manner as follows. </s></p><p type="main"> <s>Fir&longs;t, we ob&longs;erv'd that, though that <lb/>which we &longs;aw in our Receiver &longs;eem'd to <lb/>be &longs;ome kinde of Light, yet it was indeed <lb/>but a whitene&longs;s which did (as hath alrea­<lb/>dy been noted) opacate (as &longs;ome &longs;peak) <lb/>the in&longs;ide of the Gla&longs;s. </s></p><p type="main"> <s>Next we con&longs;ider'd, that our com­<lb/>mon Air abounds with Particles or little <lb/>Bodies, capable to reflect the Beams of <lb/>Light. </s> <s>Of this we might ea&longs;ily give di­<lb/>vers proofs, but we &longs;hall name but two: <lb/>The one, that vulgar ob&longs;ervation of the <lb/>Motes that appear in Multitudes &longs;wim­<lb/>ming up and down in the Air, when the <lb/>Sun-beams &longs;hooting into a Room, or any <lb/>other &longs;hady Place di&longs;cover them, though <lb/>otherwi&longs;e the eye cannot di&longs;tingui&longs;h them <pb xlink:href="013/01/339.jpg" pagenum="309"/>from the re&longs;t of the Air: The other proof <lb/>we will take from what we (and no doubt <lb/>very many others) have ob&longs;erv'd, touch­<lb/>ing the Illumination of the Air in the <lb/>Night. </s> <s>And we particularly remember, <lb/>that, being at &longs;ome di&longs;tance from <emph type="italics"/>London<emph.end type="italics"/><lb/>one Night, that the People, upon a very <lb/>well-come Occa&longs;ion, te&longs;tified their Joy <lb/>by numerous Bon-fires; though, by rea­<lb/>&longs;on of the Interpo&longs;ition of the Hou&longs;es, <lb/>we could not &longs;ee the Fires them&longs;elves, yet <lb/>we could plainly &longs;ee the Air all enlighten'd <lb/>over and near the City; which argu'd, <lb/>that the lucid Beams &longs;hot upwards from <lb/>the Fires, met in the Air with Corpu&longs;cles <lb/>opacous enough to reflect them to our <lb/>Eyes. </s></p><p type="main"> <s>A third thing that we con&longs;idered, was, <lb/>That white may be produc'd (without <lb/>excluding other ways, or denying invi&longs;i­<lb/>ble Pores in the &longs;olide&longs;t Bodies) when <lb/>the continuity of a Diaphanous Body <lb/>happens to be interrupted by a great num­<lb/>ber of Surfaces, which, like &longs;o many <lb/>little Looking-gla&longs;&longs;es, do confu&longs;edly re­<lb/>pre&longs;ent a multitude of little and &longs;eeming­<lb/>ly contiguous Images of the elucid Body. <lb/></s> <s>We &longs;hall not in&longs;i&longs;t on the explanation of <lb/>this, but refer You for it to what we have <pb xlink:href="013/01/340.jpg" pagenum="310"/>&longs;aid in another Paper (touching Co­<lb/>lours.) But the In&longs;tances that &longs;eem to <lb/>prove it are obvious: For Water or whites <lb/>of Eggs beaten to froth, do lo&longs;e their <lb/>tran&longs;parency and appear white. </s> <s>And ha­<lb/>ving out of one of our le&longs;&longs;er Receivers <lb/>carefully drawn out the Air, and &longs;o order'd <lb/>it, that the hole by which the Water was <lb/>to get in, was exceeding &longs;mall, that the <lb/>Liquor might be the more broken in its <lb/>pa&longs;&longs;age thorow it, we ob&longs;erv'd with plea­<lb/>&longs;ure, That, the Neck being held under <lb/>Water, and the little hole newly men­<lb/>tion'd being open'd, the Water that ru&longs;h'd <lb/>in was &longs;o broken, and acquired &longs;uch a mul­<lb/>titude of new Surfaces, that the Receiver <lb/>&longs;eem'd to be full rather of Milk then Wa­<lb/>ter. </s> <s>We have likewi&longs;e found out, That <lb/>by heating a lump of Cry&longs;tal to a certain <lb/>degree, and quenching it in fair Water, it <lb/>would be di&longs;continu'd by &longs;uch a multi­<lb/>tude of Cracks, (which created new Sur­<lb/>faces within it) that though it would not <lb/>fall a&longs;under, but retain its former &longs;hape, <lb/>yet it would lo&longs;e its tran&longs;parency, and ap­<lb/>pear white. </s></p><p type="main"> <s>Upon the&longs;e Con&longs;iderations, My Lord, <lb/>and &longs;ome others, it &longs;eem'd not ab&longs;ur'd to <lb/>imagine, That upon the ru&longs;hing of the Air <pb xlink:href="013/01/341.jpg" pagenum="311"/>out of the Receiver into the empty'd Cy­<lb/>linder, the Air in the Receiver being &longs;ud­<lb/>denly and vehemently expanded, the Tex­<lb/>ture of it was as &longs;uddenly alter'd, and the <lb/>parts made &longs;o to &longs;hift places (and perhaps <lb/>&longs;ome of them to change po&longs;tures) as du­<lb/>ring their new and vehement Motion and <lb/>their varied Scituation, to di&longs;turb the <lb/>wonted continuity and &longs;o the Diapha­<lb/>neity of the Air; which (as we have alrea­<lb/>dy noted) upon its cea&longs;ing to be a tran­<lb/>&longs;parent Body, without the interpo&longs;ition <lb/>of colour'd things, mu&longs;t ea&longs;ily degene­<lb/>rate into white. </s></p><p type="main"> <s>Several things there were that made <lb/>this Conjecture &longs;eem the le&longs;s improba­<lb/>ble. </s> <s>As fir&longs;t, That the whitene&longs;s al­<lb/>ways appear'd greater when the Ex&longs;ucti­<lb/>on began to be made, whil'&longs;t there was <lb/>&longs;tore of Air in the Receiver, then when <lb/>the Air was in great part drawn out. </s> <s>And <lb/>next, That, having exhau&longs;ted the Re­<lb/>ceiver, and apply'd to the hole in the <lb/>Stop-cock a large bubble of clear Gla&longs;s, in <lb/>&longs;uch a manner, that we could at plea&longs;ure let <lb/>the Air pa&longs;s out at the &longs;mall Gla&longs;s into the <lb/>great one, and ea&longs;ily fill the &longs;mall one with <lb/>Air again, We ob&longs;erv'd with plea&longs;ure, <pb xlink:href="013/01/342.jpg" pagenum="312"/>That upon the opening the pa&longs;&longs;age be­<lb/>twixt the two Gla&longs;&longs;es, the Air in the <lb/>&longs;maller having &longs;o much room in the great­<lb/>er to receive it, the Di&longs;&longs;ilition of that <lb/>Air was &longs;o great, that the &longs;mall Viol <lb/>&longs;eem'd to be full of Milk; and this Expe­<lb/>riment we repeated &longs;everal times. </s> <s>To <lb/>which we may adde, That, having pro­<lb/>vided a &longs;mall Receiver, who&longs;e upper Ori­<lb/>fice was &longs;o narrow that I could &longs;top it with <lb/>my Thumb, I ob&longs;erv'd, that when upon <lb/>the Ex&longs;uction of the Air the capacity of <lb/>the Gla&longs;s appear'd white, if by a &longs;udden <lb/>removal of my Thumb I let in the out­<lb/>ward Air, that whitene&longs;s would imme­<lb/>diately vani&longs;h. </s> <s>And whereas it may be <lb/>objected, That in the In&longs;tance formerly <lb/>mention'd, Water turning from per&longs;pi­<lb/>cuous to white, there intervenes the Air, <lb/>which is a Body of a Heterogeneous na­<lb/>ture, and mu&longs;t turn it into Bubbles to <lb/>make it lo&longs;e its tran&longs;parency. </s> <s>We may <lb/>borrow an An&longs;wer from an Experiment <lb/>we deliver in another Treati&longs;e, where we <lb/>teach how to make two very volatile Li­<lb/>quors, which being gently put together <lb/>are clear as Rock-water, and yet will al­<lb/>mo&longs;t in a moment, without the &longs;ub-ingre&longs;­<lb/>&longs;ion of Air to turn them into Bubbles, &longs;o <pb xlink:href="013/01/343.jpg" pagenum="313"/>alter the di&longs;po&longs;ition of their in&longs;en&longs;ible <lb/>parts, as to become a white and con&longs;i&longs;tent <lb/>Body. </s> <s>And this happens not as in the <lb/>precipitation of <emph type="italics"/>Benjamin,<emph.end type="italics"/> and &longs;ome o­<lb/>ther Re&longs;inous Bodies, which being di&longs;­<lb/>&longs;olv'd in Spirit of Wine, may, by the effu­<lb/>&longs;ion of fair Water, be turn'd into a &longs;eem­<lb/>ingly Milky &longs;ub&longs;tance. </s> <s>For this white­<lb/>ne&longs;s belongs not to the whole Liquor, but <lb/>to the Corpu&longs;cles of the di&longs;&longs;olv'd Gum, <lb/>which after a while &longs;ub&longs;iding leave the Li­<lb/>quor tran&longs;parent, them&longs;elves onely re­<lb/>maining white: Whereas in our ca&longs;e, 'tis <lb/>from the vary'd texture of the whole for­<lb/>merly tran&longs;parent fluid Body, and not <lb/>from this or that part that this whitene&longs;&longs;e <lb/>re&longs;ults: For the Body is white thorowout, <lb/>and will long continue &longs;o; and yet may, <lb/>in proce&longs;s of time, without any addition, <lb/>be totally reduc'd into a tran&longs;parent Bo­<lb/>dy as before. </s></p><p type="main"> <s>But be&longs;ides the Conjecture in&longs;i&longs;ted on <lb/>all this while, we grounded another upon <lb/>the following Ob&longs;ervation, which was, <lb/>That having convey'd &longs;ome &longs;moke into <lb/>our Receiver plac'd again&longs;t a Window, we <lb/>ob&longs;erv'd, that upon the ex&longs;uction of the <lb/>Air, the Corpu&longs;cles that were &longs;wimming <lb/>in it, did manife&longs;tly enough make the Re-<pb xlink:href="013/01/344.jpg" pagenum="314"/>ceiver &longs;eem more opacous at the very <lb/>moment of the ru&longs;hing out of the Air: <lb/>For con&longs;idering that the whitene&longs;s, who&longs;e <lb/>cau&longs;e we enquire of, did but &longs;ometimes ap­<lb/>pear, it &longs;eem'd not impo&longs;&longs;ible but that at <lb/>&longs;uch times the Air in the Receiver might <lb/>abound with Particles, capable of re­<lb/>flecting the Light in the manner requi&longs;ite <lb/>to exhibit a white colour, by their being <lb/>put into a certain unu&longs;ual Motion. </s> <s>As <lb/>may be in &longs;ome mea&longs;ure illu&longs;trated by <lb/>this, That the new motion of the fre&longs;hly <lb/>mention'd Fumes, made the in&longs;ide of the <lb/>Receiver appear &longs;omewhat darker then <lb/>before: And partly by the nature of our <lb/>formerly mention'd &longs;moking Liquor, <lb/>who&longs;e parts though they &longs;eem'd tran&longs;pa­<lb/>rent whil'&longs;t they compo&longs;'d a Liquor, yet <lb/>when the &longs;ame Corpu&longs;cles, upon the un­<lb/>&longs;topping of the Gla&longs;s, were put into a <lb/>new motion, and di&longs;po&longs;'d after a new <lb/>manner, they did opacate that part of the <lb/>Air they mov'd in, and exhibited a great­<lb/>er whitene&longs;s then that which &longs;ometimes <lb/>appears in our Pneumatical Ve&longs;&longs;el. </s> <s>Nor <lb/>&longs;hould we content our &longs;elves with this &longs;in­<lb/>gle In&longs;tance, to manife&longs;t, That little Bo­<lb/>dies, which being rang'd after one manner, <lb/>are Diaphanous and Colourle&longs;s, may, by <pb xlink:href="013/01/345.jpg" pagenum="315"/>being barely agitated, di&longs;per&longs;'d, and con­<lb/>&longs;equently otherways rang'd, exhibite a <lb/>colour, if we were not unwilling to rob <lb/>our Collection of Experiments concern­<lb/>ing Colours. </s></p><p type="main"> <s>But, My Lord, I fore&longs;ee You may <lb/>make &longs;ome Objections again&longs;t our pro­<lb/>po&longs;ed ghe&longs;s, which perhaps I &longs;hall &longs;carce <lb/>be able to an&longs;wer, e&longs;pecially, if You in­<lb/>&longs;i&longs;t upon having me render a Rea&longs;on why <lb/>our <emph type="italics"/>Phænomenon<emph.end type="italics"/> appears not con&longs;tant­<lb/>ly. </s></p><p type="main"> <s>I might indeed an&longs;wer, that probably <lb/>it would do &longs;o, if in&longs;tead of our great <lb/>Receiver we u&longs;e &longs;uch a &longs;mall Viol as we <lb/>have lat<emph type="italics"/>e<emph.end type="italics"/>ly mention'd, wherein the Di&longs;&longs;i­<lb/>lition of the Air being much greater, is <lb/>like to be the more con&longs;picuous: Since I <lb/>remember not that we ever made our try­<lb/>al with &longs;uch &longs;mall Ve&longs;&longs;els, without find­<lb/>ing the expected whitene&longs;s to appear. </s> <s>But <lb/>it would remain to be explicated, why in <lb/>our great Receiver the <emph type="italics"/>Phænomenon<emph.end type="italics"/> &longs;hould <lb/>&longs;ometimes be &longs;een, and oftentimes not ap­<lb/>pear. </s> <s>And though that Conjecture which <lb/>we la&longs;t made &longs;hould not be rejected, yet if <lb/>we were further pre&longs;&longs;'d to a&longs;&longs;ign a rea&longs;on <lb/>why the Air &longs;hould abound with &longs;uch Par­<lb/>ticles, as we there &longs;uppo&longs;e, more at one <pb xlink:href="013/01/346.jpg" pagenum="316"/>time then another, we are not yet pro­<lb/>vided of any better An&longs;wer, then this <lb/>general one, That the Air about us, <lb/>and much more that within the Receiver, <lb/>may be much alter'd by &longs;uch cau&longs;es as few <lb/>are aware of: For, not to repeat tho&longs;e <lb/>probable Arguments of this A&longs;&longs;ertion <lb/>which we have occa&longs;ionally mention'd <lb/>here and there in the former part of this <lb/>Epi&longs;tle, we will here &longs;et down two or <lb/>three In&longs;tances to verifie the &longs;ame Propo­<lb/>&longs;ition. </s> <s>Fir&longs;t, I finde that the Learned <lb/><emph type="italics"/>Fo&longs;ephus Aco&longs;ta,<emph.end type="italics"/> among other Judicious <lb/><arrow.to.target n="marg50"/><lb/>Ob&longs;ervations he made in <emph type="italics"/>America,<emph.end type="italics"/> hath <lb/>this concerning the Effects of &longs;ome <lb/>Winds; <emph type="italics"/>There are<emph.end type="italics"/> (&longs;ays he) <emph type="italics"/>Winds which <lb/>naturally trouble the Water of the Sea, and <lb/>make it green, and black; others, clear as <lb/>Cry&longs;tal.<emph.end type="italics"/></s><s> Next, we have ob&longs;erv'd, That <lb/>though we conveyd into the Receiver our <lb/>Scales, and the <emph type="italics"/>Pendula<emph.end type="italics"/> formerly men­<lb/>tion'd, clean and bright; yet after the Re­<lb/>ceiver had been empty'd, and the Air let in <lb/>again, the glo&longs;s or lu&longs;tre both of the one, <lb/>and of the other, appear'd tarni&longs;h'd by a <lb/>beginning ru&longs;t. </s> <s>And in the la&longs;t place, we <lb/>will &longs;ubjoyn an Ob&longs;ervation we made <lb/>&longs;ome Years ago, which hath been heard <lb/>of by divers Ingenious Men, and &longs;een <pb xlink:href="013/01/347.jpg" pagenum="317"/>by &longs;ome of them: We had, with pure <lb/>Spirit of Wine, drawn a Tincture out of <lb/>a certain Concrete which u&longs;es to be rec­<lb/>koned among Mineral Bodies; And this <lb/>Tincture being very pure and tran&longs;parent, <lb/>we did, becau&longs;e we put a great value upon <lb/>it, put into a Cry&longs;tal Viol which we care­<lb/>fully &longs;topp'd, and lock'd up in a Pre&longs;s a­<lb/>mong &longs;ome other things that we &longs;pecial­<lb/>ly priz'd. </s> <s>This Liquor being a Chy­<lb/>mical Rarity, and be&longs;ides, very defecate <lb/>and of a plea&longs;ing Golden Colour; we <lb/>had often occa&longs;ion to look upon it, and <lb/>&longs;o to take notice, that one time it &longs;eem'd <lb/>to be very much troubled, and not clear <lb/>as it was wont to be: Whereupon we ima­<lb/>gined, that though it would be &longs;omething <lb/>&longs;trange, yet it was not impo&longs;&longs;ible that <lb/>&longs;ome Precipitation of the Mineral Cor­<lb/>pu&longs;cles was then happening, and that <lb/>thence the Liquor was opacated; but, <lb/>finding after &longs;ome days that though the <lb/>expected Precipitation had not been <lb/>made, yet the Liquor, retaining its for­<lb/>mer vivid Colour, was grown clear again <lb/>as before; we &longs;omewhat wondered at it, <lb/>and locking it up again in the &longs;ame Pre&longs;s, <lb/>we re&longs;olved to ob&longs;erve, both whether <lb/>the like changes would again appear in <pb xlink:href="013/01/348.jpg" pagenum="318"/>our Tincture; and whether in ca&longs;e they <lb/>&longs;hould appear, they would be a&longs;cribable <lb/>to the alterations of the Weather. </s> <s>But <lb/>though, during the greate&longs;t part of a Win­<lb/>ter and a Spring, we took plea&longs;ure to ob­<lb/>&longs;erve, how the Liquor would often grow <lb/>turbid, and after a while clear again: Yet <lb/>we could not finde that the&longs;e Mutations <lb/>depended upon any that were manife&longs;t in <lb/>the Air, whieh would be often dark and <lb/>clouded, when the Tincture was clear and <lb/>tran&longs;parent; as on the other &longs;ide, in clear <lb/>Weather the Liquor would appear &longs;ome­<lb/>times troubled, and more opacous. </s> <s>So <lb/>that being unable to give an account of <lb/>the&longs;e odde changes in our Tincture (which <lb/>we &longs;uppo&longs;e we have not yet lo&longs;t, though <lb/>we know not whether it have lo&longs;t its fickle <lb/>Nature) either by tho&longs;e of the Air, or <lb/>any thing el&longs;e that occurr'd to our <lb/>thoughts; we could not but &longs;u&longs;pect that <lb/>there may be in divers Bodies, as it were <lb/>Spontaneous Mutations, that is, &longs;uch <lb/>changes as depend not upon manife&longs;t <lb/>Cau&longs;es. </s> <s>But, My Lord, what has been <lb/>all this while &longs;aid concerning our <emph type="italics"/>Phæno­<lb/>menon,<emph.end type="italics"/> is offer'd to You, not as contain­<lb/>ing a &longs;atisfactory Account of it, but to <lb/>a&longs;&longs;i&longs;t You to give Your&longs;elf one. </s></p><pb xlink:href="013/01/349.jpg" pagenum="319"/><p type="margin"> <s><margin.target id="marg50"/><gap/></s></p><p type="main"> <s>WE took a Gla&longs;s Ve&longs;&longs;el, open <lb/><arrow.to.target n="marg51"/><lb/>at the top, and into it we put <lb/>a mixture of Snow and common Salt <lb/>(&longs;uch a mixture as we have in another <lb/>Treati&longs;e largely di&longs;cour&longs;ed of) and in­<lb/>to the mid&longs;t of this mixture we &longs;et a <lb/>Gla&longs;&longs;e, of a Cylindrical form, clo&longs;ely <lb/>&longs;topp'd at the lower end with Plai&longs;ter, <lb/>and open at the upper, at which we <lb/>fill'd it with common Water. </s> <s>The&longs;e <lb/>things being let down into the Recei­<lb/>ver, and the Pump being &longs;et awork, <lb/>the Snow began to melt &longs;omewhat fa­<lb/>&longs;ter then we expected; whether upon <lb/>the account of the Ex&longs;uction of the <lb/>Air, or becau&longs;e there was but little of <lb/>the Snow, or whether for any other <lb/>Rea&longs;on, it appeared doubtfull. </s> <s>But <lb/>however, by that time the Receiver <lb/>had been con&longs;iderably exhau&longs;ted, which <lb/>was done in le&longs;&longs;e then 1/4 of an hour, <lb/>we perceived the Water near the bot­<lb/>tom of the Gla&longs;s Cylinder to Freeze, <lb/>and the Ice by a little longer &longs;tay, &longs;eem'd <lb/>to encrea&longs;e, and to ri&longs;e &longs;omewhat higher <pb xlink:href="013/01/350.jpg" pagenum="320"/>then the &longs;urface of the &longs;urrounding Li­<lb/>quor, where into almo&longs;t all the Snow and <lb/>Salt were re&longs;olv'd. </s> <s>The Gla&longs;s being ta­<lb/>ken out, it appear'd that the Ice was as <lb/>thick as the in&longs;ide of the Gla&longs;s it fill'd, <lb/>though into that I could put my Thumb. <lb/></s> <s>The upper &longs;urface of the Ice was very <lb/>concave, which whether it were due to <lb/>any unheeded accident, or to the ex&longs;u­<lb/>ction of the Air, we leave to be deter­<lb/>min'd by further tryal. </s> <s>And la&longs;tly, the <lb/>Ice held again&longs;t the Light, appear'd not <lb/>de&longs;titute of Bubbles, though &longs;ome By­<lb/>&longs;tanders thought they were fewer then <lb/>would have been found if the Water had <lb/>been frozen in the open Air. </s> <s>The like <lb/>Experiment we try'd al&longs;o another time in <lb/>one of our &longs;mall Receivers, with not un­<lb/>like &longs;ucce&longs;s. </s></p><p type="margin"> <s><margin.target id="marg51"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 38.</s></p><p type="main"> <s>And on this occa&longs;ion, My Lord, give <lb/>me leave to propo&longs;e a Problem, which <lb/>&longs;hall be this: Whence proceeds that <lb/>&longs;trange force that we may &longs;ometimes ob­<lb/>&longs;erve in frozen Water, to break the Bo­<lb/>dies that Impri&longs;on it, though hard and &longs;o­<lb/>lid? </s> <s>That there is &longs;uch a force in Wa­<lb/>ter expo&longs;'d to Congelation, may be ga­<lb/>ther'd not onely from what may be often <lb/>ob&longs;erv'd in Winter, of the bur&longs;ting of <pb xlink:href="013/01/351.jpg" pagenum="321"/>Gla&longs;&longs;es too clo&longs;e &longs;topp'd, fill'd with Wa­<lb/>ter or aqueous Liquors, but by In&longs;tances <lb/>as much more con&longs;iderable as le&longs;s obvi­<lb/>ous. </s> <s>For I remember, that an Ingenious <lb/>Stone-cutter not long &longs;ince complain'd to <lb/>me, That &longs;ometimes, through the negli­<lb/>gence of Servants, the Rain being &longs;uffer­<lb/>ed to &longs;oak into Marble Stones, the &longs;uper­<lb/>vening violent Fro&longs;ts would bur&longs;t the <lb/>Stones, to the Profe&longs;&longs;ors no &longs;mall dam­<lb/>age. </s> <s>And I remember another Trades­<lb/>man, in who&longs;e Hou&longs;e I had Lodgings, was <lb/>la&longs;t Winter complaining, that even Im­<lb/>plements made of Bell-metal, being care­<lb/>le&longs;ly expo&longs;'d to the wet, have been broken <lb/>and &longs;poil'd by the Water, which, having <lb/>gotten into the little Cavities and Cran­<lb/>nies of the Metal, was there afterwards <lb/>frozen and expanded into Ice. </s> <s>And to <lb/>the&longs;e Relations, we can adde one of the <lb/><arrow.to.target n="marg52"/><lb/>formerly mention'd <emph type="italics"/>Cabæus's,<emph.end type="italics"/> whereby <lb/>they not onely may be confirm'd, but are <lb/>&longs;urpa&longs;&longs;'d: For he tells us, That he &longs;aw a <lb/>huge Ve&longs;&longs;el of exceeding hard Marble, <lb/>&longs;plit a&longs;under by congel'd Water, who&longs;e <lb/>Rarefaction, &longs;ays our Author, prov'd &longs;o <lb/>vehement, that the hardne&longs;s of the Stone <lb/>yielded to it; and &longs;o a Ve&longs;&longs;el was broken, <lb/>which would not have been &longs;o by 100 <pb xlink:href="013/01/352.jpg" pagenum="322"/>Yoke of Oxen drawing it &longs;everal ways. </s> <s>I <lb/>know, My Lord, that to &longs;olve this Pro­<lb/>blem, it will be &longs;aid, That Congelation <lb/>does not (as is commonly, but erroneou&longs;ly <lb/>pre&longs;um'd) reduce water into le&longs;s room <lb/>then it po&longs;&longs;e&longs;&longs;'d before, but rather makes <lb/>it take up more. </s> <s>And I have el&longs;ewhere <lb/>prov'd by particular Experiments, That <lb/>whether or no Ice may be truly &longs;aid to be <lb/>Water rarefi'd (for that &longs;eems que&longs;tion­<lb/>able) it may be &longs;aid to take up more room <lb/>then the Water did before Glaciation. <lb/></s> <s>But though we grant that freezing makes <lb/>Water &longs;well, yet, how Cold (which in <lb/>Weather-Gla&longs;&longs;es manife&longs;tly condences <lb/>the Air) &longs;hould expand either the Water, <lb/>or the intercepted Air &longs;o forcibly, as to <lb/>perform &longs;uch things as we have newly re­<lb/>lated, will yet remain a Problem. </s></p><p type="margin"> <s><margin.target id="marg52"/><emph type="italics"/>In <gap/>.<emph.end type="italics"/> 4. <lb/><gap/></s></p><p type="main"> <s>WE took an Oval Gla&longs;s, clear and <lb/><arrow.to.target n="marg53"/><lb/>(lea&longs;t it &longs;hould break) pretty <lb/>&longs;trong, with a &longs;hort Neck at the obtu&longs;er <lb/>end, through this Neck, we thru&longs;t almo&longs;t <lb/>to the bottom, a Pipe of Gla&longs;s, which was <lb/>clo&longs;ely Cemented to the newly mention'd <lb/>Neck, the upper part of which Pipe, <lb/>was drawn in &longs;ome places more &longs;lender <pb xlink:href="013/01/353.jpg" pagenum="323"/>then a Crows Quill, that the changes of <lb/>the Air in that. </s> <s>Gla&longs;s Egge might be the <lb/>more con&longs;picuous; Then there was con­<lb/>vey'd into the Gla&longs;s five or &longs;ix Spoon­<lb/>fulls of Water, part of which, by blow­<lb/>ing Air into the Egge, was rai&longs;'d into the <lb/>above-mention'd &longs;lender part of the Pipe, <lb/>&longs;o that the Water was interpo&longs;'d between <lb/>the external Air, and that included in the <lb/>Egge. </s> <s>This Weather-gla&longs;s (delineated <lb/>in the fourteenth Figure) was &longs;o plac'd, <lb/>and clo&longs;'d up in the cavity of one of our <lb/>&longs;mall Receivers, that onely the &longs;lender <lb/>part of the Pipe, to the heigth of four <lb/>or five Inches, pa&longs;&longs;ing thorow a hole in <lb/>the Cover, remain'd expo&longs;'d to the open <lb/>Air. </s></p><p type="margin"> <s><margin.target id="marg53"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 39.</s></p><p type="main"> <s>The Pump being &longs;et a work, upon <lb/>the Ex&longs;uction of the Air, the Water in <lb/>the Pipe de&longs;cended about a quarter of an <lb/>Inch, and this upon two or three reitera­<lb/>ted tryals; which &longs;eem'd &longs;ufficiently to <lb/>argue that there was no heat produc'd in <lb/>the Receiver upon the Ex&longs;uction of the <lb/>Air: For even a little heat would pro­<lb/>bably have been di&longs;cover'd by that Wea­<lb/>ther-gla&longs;s, &longs;ince upon the bare applica­<lb/>tion of my hand to the out&longs;ide of the <lb/>Receiver, the warmth having after &longs;ome <pb xlink:href="013/01/354.jpg" pagenum="324"/>time been communicated or propagated <lb/>through both the Gla&longs;&longs;es, and the inter­<lb/>val betwixt them to the Impri&longs;on'd Air, <lb/>did &longs;o rarifie that, as to inable it, by pre&longs;­<lb/>&longs;ing upon the &longs;ubjacent Water, to impel <lb/>that in the Pipe very many times as far as <lb/>it had fallen downwards upon the Ex&longs;ucti­<lb/>on of the Air. </s></p><p type="main"> <s>Yet &longs;hall not we conclude, that in the <lb/>cavity of the Receiver the cold was great­<lb/>er after the Ex&longs;uction of the Air then be­<lb/>fore. </s></p><p type="main"> <s>For if it be demanded what then could <lb/>cau&longs;e the fore-mention'd &longs;ub&longs;iding of the <lb/>Water? </s> <s>it may be an&longs;wered, That pro­<lb/>bably it was the reaching of the Gla&longs;s <lb/>Egge, which, upon the Ex&longs;uction of the <lb/>ambient Air, was unable to re&longs;i&longs;t alto­<lb/>gether as much as formerly the pre&longs;&longs;ure of <lb/>the included Air, and of the Atmo&longs;phere, <lb/>which by the interven&longs;ion of the Water, <lb/>pre&longs;&longs;'d upon its concave &longs;urface: Which <lb/>&longs;eem'd probable, as well by what was a­<lb/>bove deliver'd, in the Experiment about <lb/>the breaking of the Gla&longs;s by the force of <lb/>the Atmo&longs;phere; as by this notable Cir­<lb/>cum&longs;tance (which we divers times ob­<lb/>&longs;erv'd) That when by drawing the Air out <lb/>of the Receiver, the Water in the Pipe <pb xlink:href="013/01/355.jpg" pagenum="325"/>was &longs;ub&longs;ided, upon the readmi&longs;&longs;ion of the <lb/>external Air to pre&longs;s again&longs;t the convex <lb/>&longs;urface of the Egge, the Water was pre­<lb/>&longs;ently re-impell'd to its former height: <lb/>Which would perhaps appear le&longs;s &longs;trange <lb/>to Your Lord&longs;hip, if You had yet &longs;een <lb/>what we have heretofore taught in ano­<lb/>ther Treati&longs;e concerning the Spring that <lb/>may be di&longs;cover'd in Gla&longs;s, as rigid and <lb/>inflexible a Body as it is generally e­<lb/>&longs;teem'd. </s> <s>And in the mean while it may <lb/>&longs;erve the turn to cau&longs;e a Gla&longs;s Egge to be <lb/>blown exceeding thin, and then, having <lb/>broken it, try how far you can by degrees <lb/>bend &longs;ome narrow parts of it; and how <lb/>readily, upon the removal of what kept <lb/>it bent, it will re&longs;tore it &longs;elf to its former <lb/>&longs;tate or po&longs;ture. </s> <s>But to return to our <lb/>Experiment, From thence it &longs;eems pro­<lb/>bable, either that there &longs;ucceeds no Bo­<lb/>dy in the room of the Air drawn out of <lb/>our Receiver, or that it is not every Mat­<lb/>ter that is &longs;ubtle enough readily to pa&longs;s <lb/>through the Pores of Gla&longs;s, that is al­<lb/>ways agitated enough to produce Heat <lb/>where ever it is plentifully found. </s> <s>So that <lb/>if no <emph type="italics"/>Vacuum<emph.end type="italics"/> be to be admitted, this Ex­<lb/>periment &longs;eems to invite us to allow a <lb/>great di&longs;parity, either as to bulk, or as to <pb xlink:href="013/01/356.jpg" pagenum="326"/>agitation, or as to both, betwixt &longs;ome <lb/>parts of the Etherial Sub&longs;tance, and tho&longs;e <lb/>that are wont here below to produce Heat <lb/>and Fire. </s></p><p type="main"> <s>We try'd al&longs;o what Operation the <lb/>drawing out of the Air would have upon <lb/>Camphire, that being a Body, which, <lb/>though not a Liquor, con&longs;i&longs;ts of &longs;uch <lb/>Volatile or Fugitive parts, that without <lb/>any greater agitation then that of the open <lb/>Air it &longs;elf, they will copiou&longs;ly flie away. <lb/></s> <s>But we found not that even this loo&longs;e <lb/>Body was &longs;en&longs;ibly alter'd by the Ex&longs;ucti­<lb/>on of the ambient Air. </s></p><p type="main"> <s>IT may &longs;eem well worth trying, whether <lb/><arrow.to.target n="marg54"/><lb/>or no in our exhau&longs;ted Gla&longs;s the want <lb/>of an ambient Body, of the wonted thic­<lb/>ne&longs;s of Air, would di&longs;able even light and <lb/>little Animals, as Bees, and other winged <lb/>In&longs;ects, to flie. </s> <s>But though we ea&longs;ily <lb/>fore&longs;aw how difficult it would be to make <lb/>&longs;uch an Experiment; yet not to omit our <lb/>endeavors, we procur'd a large Fle&longs;h-fly, <lb/>which we convey'd into a &longs;mall Receiver. <lb/></s> <s>We al&longs;o another time &longs;hut into a great <lb/>Receiver a Humming Bee, that appear'd <lb/>&longs;trong and lively, though we had rather <pb xlink:href="013/01/357.jpg" pagenum="327"/>have made the tryal with a Butter-fly, if <lb/>the cold Sea&longs;on would have permitted us <lb/>to finde any. The Fly, af­<lb/>ter &longs;ome Ex&longs;uctions of the <lb/>Air, dropp'd down from the <lb/>&longs;ide of the Gla&longs;s whereon &longs;he <lb/>was walking: But, that the <lb/>Experiment with the Bee <lb/>might be the more in&longs;tructive, <lb/>we convey'd in with her a bun­<lb/>dle of Flowers, which re­<lb/>main'd &longs;u&longs;pended by a &longs;tring <lb/>near the upper part of the Receiver: And <lb/>having provok'd the Bee, we excited her <lb/>to flie up and down the capacity of the <lb/>Ve&longs;&longs;el, till at length, as we de&longs;ir'd, &longs;he <lb/>lighted upon the Flowers; whereupon <lb/>we pre&longs;ently began to draw out the Air, <lb/>and ob&longs;erv'd, That though for &longs;ome time <lb/>the Bee &longs;eem'd to take no notice of it, yet <lb/>within awhile after &longs;he did not flie, but fall <lb/>down from rhe Flowers, without appear­<lb/>ing to make any u&longs;e of her Wings to help <lb/>her &longs;elf. </s> <s>But whether this fall of the Bee, <lb/>and the other In&longs;ect, proceeded from the <lb/>mediums being too thin for them to flie in, <lb/>or barely from the weakne&longs;s, and as it were <lb/>&longs;wooning of the Animals them&longs;elves, you <lb/>will ea&longs;ily gather from the following Ex­<lb/>periment. </s></p><pb xlink:href="013/01/358.jpg" pagenum="328"/><p type="margin"> <s><margin.target id="marg54"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 40.</s></p><p type="main"> <s>TO &longs;atisfie our &longs;elves in &longs;ome mea&longs;ure, <lb/><arrow.to.target n="marg55"/><lb/>about the account upon which Re&longs;pira­<lb/>tion is &longs;o nece&longs;&longs;ary to the Animals, that <lb/>Nature hath furni&longs;h'd with Lungs, we <lb/>took (being then unable to procure any <lb/>other lively Bird, &longs;mall enough to be put <lb/>into the Receiver) a Lark, one of who&longs;e <lb/>Wings had been broken by a &longs;hot, of a <lb/>Man that we had &longs;ent to provide us &longs;ome <lb/>Birds for our Experiment; but notwith­<lb/>&longs;tanding this hurt, the Lark was very <lb/>lively, and did, being put into the Recei­<lb/>ver, divers times &longs;pring up in it to a good <lb/>height. </s> <s>The Ve&longs;&longs;el being ha&longs;tily, but <lb/>carefully clo&longs;'d, the Pump was diligently <lb/>ply'd, and the Bird for a while appear'd <lb/>lively enough; but upon a greater Ex­<lb/>&longs;uction of the Air, &longs;he began manife&longs;tly <lb/>to droop and appear &longs;ick, and very &longs;oon <lb/>after was taken with as violent and irregu­<lb/>lar Convul&longs;ions, as are wont to be ob­<lb/>&longs;erv'd in Poultry, when their heads are <lb/>wrung off: For the Bird threw her &longs;elf <lb/>over and over two or three times, and dy­<lb/>ed with her Brea&longs;t upward, her Head <lb/>downwards, and her Neck awry. </s> <s>And <lb/>though upon the appearing of the&longs;e Con-<pb xlink:href="013/01/359.jpg" pagenum="329"/>vul&longs;ions, we turn'd the Stop-cock, and <lb/>let in the Air upon her, yet it came too <lb/>late; whereupon, ca&longs;ting our eyes upon <lb/>one of tho&longs;e accurate Dyals that go with <lb/>a <emph type="italics"/>Pendulum,<emph.end type="italics"/> and were of late ingeniou&longs;ly <lb/>invented by the Noble and Learned <emph type="italics"/>Hu­<lb/>genius,<emph.end type="italics"/> we found that the whole Tragedy <lb/>had been concluded within ten Minutes of <lb/>an hour, part of which time had been im­<lb/>ploy'd in cementing the Cover to the Re­<lb/>ceiver. </s> <s>Soon after we got a Hen-&longs;par­<lb/>row, which being caught with Bird-lime <lb/>was not at all hurt; when we put her into <lb/>the Receiver, almo&longs;t to the top of which <lb/>&longs;he would briskly rai&longs;e her &longs;elf, the Ex­<lb/>periment being try'd with this Bird, as it <lb/>was with the former, &longs;he &longs;eem'd to be <lb/>dead within &longs;even minutes, one of which <lb/>were imploy'd in cementing on the Co­<lb/>ver: But upon the &longs;peedy turning of the <lb/>Key, the fre&longs;h Air flowing in, began &longs;low­<lb/>ly to revive her, &longs;o that after &longs;ome pant­<lb/>ings &longs;he open'd her eyes, and regain'd her <lb/>feet, and in about a 1/4 of an hour, after <lb/>threatned to make an e&longs;cape at the top of <lb/>the Gla&longs;s, which had been un&longs;topp'd to <lb/>let in the fre&longs;h Air upon her: But the Re­<lb/>ceiver being clo&longs;'d the &longs;econd time, &longs;he <pb xlink:href="013/01/360.jpg" pagenum="330"/>was kill'd with violent Convul&longs;ions, <lb/>within five Minutes from the beginning <lb/>of the Pumping. </s></p><p type="margin"> <s><margin.target id="marg55"/><emph type="italics"/>Experi­<lb/>ment<emph.end type="italics"/> 41.</s></p><p type="main"> <s>A while after we put in a Mou&longs;e, new­<lb/>ly taken, in &longs;uch a Trap as had rather af­<lb/>frighted then hurt him; vvhil'&longs;t he vvas <lb/>leaping up very high in the Receiver, vve <lb/>fa&longs;ten'd the Cover to it, expecting that <lb/>an Animal u&longs;ed to live in narrow holes <lb/>vvith very little fre&longs;h Air, vvould endure <lb/>the vvant of it better then the lately men­<lb/>tion'd Birds: But though, for a vvhile af­<lb/>ter the Pump vvas &longs;et avvork, he conti­<lb/>nued leaping up as before; yet 'tvvas not <lb/>long ere he began to appear &longs;ick and gid­<lb/>dy, and to &longs;tagger, after vvhich he fell <lb/>dovvn as dead, but vvithout &longs;uch violent <lb/>Convul&longs;ions as the Birds died vvith. <lb/></s> <s>Whereupon, ha&longs;tily turning the Key, we <lb/>let in &longs;ome fre&longs;h Air upon him, by vvhich <lb/>he recovered, after a vvhile, his &longs;en&longs;es and <lb/>his feet, but &longs;eem'd to continue vveak and <lb/>&longs;ick: But at length, grovving able to <lb/>skip as formerly, the Pump vvas plyed <lb/>again for eight minutes, about the mid­<lb/>dle of vvhich &longs;pace, if not before, a very <lb/>little Air by a mi&longs;chance got in at the <lb/>Stop-cock; and about tvvo minutes after <lb/>that, the Mou&longs;e divers times leap'd up <pb xlink:href="013/01/361.jpg" pagenum="331"/>lively enough, though after about two mi­<lb/>nutes more he fell down quite dead, yet <lb/>with Convul&longs;ions far milder then tho&longs;e <lb/>wherewith the two Birds expired. </s> <s>This <lb/>alacrity &longs;o little before his death, and his <lb/>not dying &longs;ooner then at the end of the <lb/>eighth minute, &longs;eem'd a&longs;cribable to the <lb/>Air (how little &longs;oever) that &longs;lipt into the <lb/>Receiver. </s> <s>For the fir&longs;t time, tho&longs;e Con­<lb/>vul&longs;ions (that, if they had not been &longs;ud­<lb/>denly remedied, had immediately di&longs;­<lb/>patch'd him) &longs;ei&longs;'d on him in &longs;ix minutes <lb/>after the Pump began to be &longs;et awork. <lb/></s> <s>The&longs;e Experiments &longs;eem'd the more <lb/>&longs;trange, in regard, that during a great part of <lb/>tho&longs;e few minutes the Engine could but <lb/>con&longs;iderably rarefie the Air (and that too, <lb/>but by degrees) and at the end of them <lb/>there remain'd in the Receiver no incon­<lb/>&longs;iderable quantity; as may appear by what <lb/>we have formerly &longs;aid of our not being <lb/>able to draw down Water in a Tube, with­<lb/>in much le&longs;s then a Foot of the bottom: <lb/>with which we likewi&longs;e con&longs;ider'd, that by <lb/>the ex&longs;uction of the Air and inter&longs;per­<lb/>&longs;ed Vapors, there was left in the Recei­<lb/>ver a &longs;pace &longs;ome hundreds of times ex­<lb/>ceeding the bigne&longs;s of the Animal, to re­<lb/>ceive the fuliginous Steams, from which, <pb xlink:href="013/01/362.jpg" pagenum="332"/>expiration di&longs;charges the Lungs; and, <lb/>which in the other ca&longs;es hitherto known, <lb/>may be &longs;u&longs;pected, for want of room, to <lb/>&longs;tifle tho&longs;e Animals that are clo&longs;ely pent <lb/>up in too narrow Receptacles. </s></p><p type="main"> <s>I forgot to mention, that having cau&longs;'d <lb/>the&longs;e three Creatures to be open'd, I <lb/>could, in &longs;uch &longs;mall Bodies, di&longs;cover lit­<lb/>tle of what we &longs;ought for, and what we <lb/>might po&longs;&longs;ibly have found in larger Ani­<lb/>mals; for though the Lungs of the Birds <lb/>appear'd very red, and as it were inflam'd, <lb/>yet that colour being u&longs;ual enough in the <lb/>Lungs of &longs;uch winged Creatures, de&longs;erves <lb/>not &longs;o much our notice, as it does, That <lb/>in almo&longs;t all the de&longs;tructive Experiments <lb/>made in our Engine, the Animals appear'd <lb/>to die with violently Convul&longs;ive Moti­<lb/>ons: From which, whether Phy&longs;icians can <lb/>gather any thing towards the Di&longs;covery <lb/>of the Nature of Convul&longs;ive Di&longs;tem­<lb/>pers, I leave to them to con&longs;ider. </s></p><p type="main"> <s>Having proceeded thus far, though (as <lb/>we have partly intimated already) there <lb/>appear'd not much cau&longs;e to doubt, but <lb/>that the death of the fore-mention'd Ani­<lb/>mals proceeded rather from the want of <lb/>Air, then that the Air was over-clogg'd <lb/>by the &longs;teams of their Bodies, exqui&longs;ite-<pb xlink:href="013/01/363.jpg" pagenum="333"/>ly pent up in the Gla&longs;s; yet I, that love <lb/>not to believe any thing upon Conje­<lb/>ctures, when by a not over-difficult Ex­<lb/>periment I can try whether it be True or <lb/>no, thought it the &longs;afe&longs;t way to obviate <lb/>Objections, and remove Scruples, by &longs;hut­<lb/>ting up another Mou&longs;e as clo&longs;e as I could <lb/>in the Receiver, wherein it liv'd above <lb/>three quarters of an hour; and might pro­<lb/>bably have done &longs;o much longer, had not <lb/>a <emph type="italics"/>Virtuo&longs;o<emph.end type="italics"/> of quality, who in the mean <lb/>while chanc'd to make me a Vi&longs;it, de&longs;ir'd <lb/>to &longs;ee whether or no the Mou&longs;e could be <lb/>kill'd by the ex&longs;uction of the ambient Air, <lb/>whereupon we thought fit to open, for a <lb/>little while, an intercour&longs;e betwixt the <lb/>Air in the Receiver, and that without it, <lb/>that the Mou&longs;e might thereby (if it were <lb/>needful for him) be refre&longs;h d, and yet we <lb/>did this without uncementing the Cover <lb/>at the top, that it might not be objected, <lb/>that perhaps the Ve&longs;&longs;el was more clo&longs;ely <lb/>&longs;topp'd for the ex&longs;uction of the Air then <lb/>before. </s></p><p type="main"> <s>The Experiment had this event, that <lb/>after the Mou&longs;e had liv'd ten Minutes, <lb/>(which we a&longs;crib'd to this, that the Pump, <lb/>for want of having been lately Oyl'd, <lb/>could move but &longs;lowly, and could not by <pb xlink:href="013/01/364.jpg" pagenum="334"/>him that manag'd it, be made to work as <lb/>nimbly as it was wont) at the end of that <lb/>time he dy'd with Convul&longs;ive Fits, where­<lb/>in he made two or three bounds into the <lb/>Air, before he fell down dead. </s></p><p type="main"> <s>Nor was I content with this, but for <lb/>Your Lord&longs;hips further &longs;atisfaction, and <lb/>my own, I cau&longs;'d a Mou&longs;e, that was very <lb/>hungry, to be &longs;hut in all Night, with a <lb/>Bed of Paper for him to re&longs;t upon: And <lb/>to be &longs;ure that the Receiver was well <lb/>clo&longs;'d, I cau&longs;'d &longs;ome Air to be drawn out <lb/>of it, whereby, perceiving that there <lb/>was no &longs;en&longs;ible leak, I pre&longs;ently re-ad­<lb/>mitted the Air at the Stop-cock, le&longs;t the <lb/>want of it &longs;hould harm the little Animal; <lb/>and then I cau&longs;'d the Engine to be kept <lb/>all Night by the Fire &longs;ide, to keep him <lb/>from being de&longs;troy'd by the immoderate <lb/>cold of the Fro&longs;ty Night. </s> <s>And this care <lb/>&longs;ucceeded &longs;o well, that the next Morning <lb/>I found that the Mou&longs;e not onely was a­<lb/>live, but had devour'd a good part of the <lb/>Chee&longs;e that had been put in with him. </s> <s>And <lb/>having thus kept him alive full twelve <lb/>hours, or better, we did, by &longs;ucking out <lb/>part of the Air, bring him to droop, and <lb/>to appear &longs;well'd; and by letting in the <lb/>Air again, we &longs;oon reduc'd him to his for­<lb/>mer liveline&longs;s. </s></p><pb xlink:href="013/01/365.jpg" pagenum="335"/><p type="main"> <s><emph type="center"/><emph type="italics"/>A Digre&longs;sion containing &longs;ome <lb/>Doubts touching Re&longs;pi­<lb/>ration.<emph.end type="italics"/><emph.end type="center"/></s></p><p type="main"> <s>I Fear Your Lord&longs;hip will now expect, <lb/>that to the&longs;e Experiments I &longs;hould add <lb/>my Reflections on them, and attempt, <lb/>by their a&longs;&longs;i&longs;tance, to re&longs;olve the Diffi­<lb/>culties that occur about Re&longs;piration; &longs;ince <lb/>at the beginning I acknowledg'd a further <lb/>Enquiry into the Nature of that, to have <lb/>been my De&longs;ign in the related Tryals. <lb/></s> <s>But I have yet, becau&longs;e of the inconve­<lb/>nient Sea&longs;on of the Year, made &longs;o few <lb/>Experiments, and have been &longs;o little &longs;a­<lb/>tisfied by tho&longs;e I have been able to make, <lb/>that they have hitherto made Re&longs;piration <lb/>appear to me rather a more, then a le&longs;s <lb/>My&longs;terious thing, then it did before. </s> <s>But <lb/>yet, &longs;ince they have furni&longs;h'd me with <lb/>&longs;ome &longs;uch new Con&longs;iderations, concern­<lb/>ing the u&longs;e of the Air, as confirms me in <lb/>my Diffidence of the Truth of what is <lb/>commonly believ'd touching that matter; <lb/>That I may not appear &longs;ullen or lazy, I <lb/>am content not to decline employing a <pb xlink:href="013/01/366.jpg" pagenum="336"/>few hours in &longs;etting down my Doubts, in <lb/>pre&longs;enting Your Lord&longs;hip &longs;ome Hints, <lb/>and in con&longs;idering whether the Tryals <lb/>made in our Engine, will at lea&longs;t a&longs;&longs;i&longs;t us <lb/>to di&longs;cover wherein the Deficiency lies <lb/>that needs to be &longs;upply'd. </s></p><p type="main"> <s>And this, My Lord, being all my pre­<lb/>&longs;ent De&longs;ign, I &longs;uppo&longs;e You will not ex­<lb/>pect that (as if You knew not, or had for­<lb/>gotten what Anatomi&longs;ts are wont to <lb/>teach) I &longs;hould entertain You with a need­<lb/>le&longs;s Di&longs;cour&longs;e of the Organs of Re&longs;pira­<lb/>tion, and the variety of their Structure in <lb/>&longs;everal Animals; though if it were ne­<lb/>ce&longs;&longs;ary, and had not been perform'd by o­<lb/>thers, I &longs;hould think, with <emph type="italics"/>Galen,<emph.end type="italics"/> that by <lb/><arrow.to.target n="marg56"/><lb/>treating of the Fabricks of living Bodies, <lb/>I might compo&longs;e Hymns to the wi&longs;e Au­<lb/>thor of Nature, who, in the excellent con­<lb/>trivance of the Lungs, and other parts of <lb/>(tho&longs;e admirable Engines) Animals, ma­<lb/>nife&longs;ts him&longs;elf to be indeed what the Elo­<lb/>quent Prophet mo&longs;t ju&longs;tly &longs;peaks him, <lb/><emph type="italics"/>Wonderful in Counsel, and excellent in<emph.end type="italics"/><lb/><arrow.to.target n="marg57"/><lb/><emph type="italics"/>working.<emph.end type="italics"/></s></p><p type="margin"> <s><margin.target id="marg56"/><emph type="italics"/>Galenus de <lb/><gap/>, Part: <lb/>lib. <emph.end type="italics"/> 3.</s></p><p type="margin"> <s><margin.target id="marg57"/><gap/>a.28.29.</s></p><p type="main"> <s>Nor &longs;hall we any further meddle with <lb/>tho&longs;e Controver&longs;ies &longs;o much agitated a­<lb/>mong the Moderns, namely, <emph type="italics"/>Whether the <lb/>motion of the Lungs in Re&longs;piration be their<emph.end type="italics"/><pb xlink:href="013/01/367.jpg" pagenum="337"/><emph type="italics"/>own, or but con&longs;equent to the motion of the <lb/>Thorax, Diaphragme, and<emph.end type="italics"/> (as &longs;ome Learn­<lb/>ed Men would have it) <emph type="italics"/>the Abdomen; And, <lb/>Whence it is that the Air &longs;wells the Lungs <lb/>in In&longs;piration<emph.end type="italics"/> any further then they may <lb/>receive light from our Engine: But that <lb/>it may appear what kinde of &longs;ervice it is <lb/>that may be expected from it on this oc­<lb/>ca&longs;ion, we mu&longs;t premi&longs;e a few Words to <lb/>&longs;hew wherein the &longs;trength of the Obje­<lb/>ction we are to an&longs;wer, lies. </s> <s>In favor then <lb/>of tho&longs;e that would have the Lungs ra­<lb/>ther pa&longs;&longs;ive then active in the bu&longs;ine&longs;s of <lb/>Re&longs;piration, it may again&longs;t the common <lb/>opinion be alledg'd, That as the Lungs be­<lb/>ing de&longs;titute of Mu&longs;cles and of Fibres, <lb/>are unfit to dilate them&longs;elves; &longs;o it ap­<lb/>pears, that without the motion of the <lb/><emph type="italics"/>Thorax<emph.end type="italics"/> they would not be fill'd with Air. <lb/></s> <s>Since as our Learned Friend Dr. <emph type="italics"/>High­<lb/>more<emph.end type="italics"/> has well (and congruou&longs;ly, to what <lb/>our &longs;elves have purpo&longs;ely try'd) ob­<lb/>&longs;erv'd, if a live Dog have a great wound <lb/>made in his Che&longs;t, the Lobes of the <lb/>Lungs on that &longs;ide of the <emph type="italics"/>Media&longs;ti­<lb/>num<emph.end type="italics"/> will &longs;ub&longs;ide and lie &longs;till; the <emph type="italics"/>Tho­<lb/>rax<emph.end type="italics"/> and the Lobes on the other &longs;ide <lb/>of the <emph type="italics"/>Media&longs;tinum,<emph.end type="italics"/> continuing their <lb/>former motion. </s> <s>And if &longs;uddenly at once <pb xlink:href="013/01/368.jpg" pagenum="338"/>the Mu&longs;cles of the Che&longs;t be on both <lb/>&longs;ides di&longs;&longs;ected, upon the Ingre&longs;s of the <lb/>Air, the whole Lungs, though untouch'd, <lb/>will remain movele&longs;s, at lea&longs;t, as to any ex­<lb/>pan&longs;ion or contraction of their &longs;ub&longs;tance. </s></p><p type="main"> <s>To which we may adde the Ob&longs;ervati­<lb/>on of the diligent <emph type="italics"/>Bartholinus,<emph.end type="italics"/> who af­<lb/>firms the like of the <emph type="italics"/>Diaphragme<emph.end type="italics"/> al­<lb/>&longs;o, namely, That it being wounded, the <lb/>Lungs will fall together, and the Re&longs;pi­<lb/>ration cea&longs;e, which my Experiments op­<lb/>po&longs;e not, provided the Wound be any <lb/>thing great. </s> <s>And indeed the <emph type="italics"/>Diaphragme<emph.end type="italics"/><lb/>&longs;eems the principal In&longs;trument of ordina­<lb/>ry and gentle Re&longs;piration, although to <lb/>re&longs;train'd Re&longs;piration (if I may &longs;o call <lb/>it) the interco&longs;tal Mu&longs;cles, and perhaps <lb/>&longs;ome others may be allowed eminently to <lb/>concur. </s> <s>But the chief of the Contro­<lb/>ver&longs;ies formerly pointed at, is not yet de­<lb/>cided, namely, what it is that conveys the <lb/>Air into the Lungs. </s> <s>For when, to coun­<lb/>terballance all that has been alledg'd, tho&longs;e <lb/>that plead for the Lungs, demand what it <lb/>is that &longs;hould bring the Air into the <lb/>Lungs, if them&longs;elves do not attract it, <lb/>their Antagoni&longs;ts di&longs;agree about the Re­<lb/>ply. </s> <s>For when to this que&longs;tion &longs;ome of <lb/>the be&longs;t Modern Philo&longs;ophers an&longs;wer, <pb xlink:href="013/01/369.jpg" pagenum="339"/>that by the dilatation of the Che&longs;t the <lb/>contiguous Air is thru&longs;t away, and that <lb/>pre&longs;&longs;ing upon the next Air to it, and &longs;o <lb/>onwards, the Propul&longs;ion is continued till <lb/>the Air be driven into the Lungs, and &longs;o <lb/>dilate them: When this (I &longs;ay) is an­<lb/>&longs;wered, it is Objected even by <emph type="italics"/>Bartholine<emph.end type="italics"/><lb/>him&longs;elf, as a convincing Reply, that, ac­<lb/>cording to this Doctrine, a Man could not <lb/>fetch his Breath from a great Ve&longs;&longs;el full of <lb/>Air, with a &longs;lender Neck, becau&longs;e, that <lb/>when his Mouth covers the Orifice of the <lb/>Neck, the dilatation of his <emph type="italics"/>Thorax<emph.end type="italics"/> could <lb/>not propell the Air in the Ve&longs;&longs;el into his <lb/>Lungs, by rea&longs;on of its being &longs;eparated <lb/>by the inclo&longs;ing Ve&longs;&longs;el from the ambient <lb/>Air; and yet, &longs;ay they, Experience wit­<lb/>ne&longs;&longs;es that out of &longs;uch a Ve&longs;&longs;el a Man may <lb/>&longs;uck Air. </s> <s>But of this difficulty our Engine <lb/>furni&longs;hes us with an ea&longs;ie Solution, &longs;ince <lb/>many of the former Experiments have ma­<lb/>nife&longs;ted, That in the ca&longs;e propo&longs;ed, there <lb/>needs not be made any (though 'tis true <lb/>that in ordinary Re&longs;piration there is wont <lb/>to be made &longs;ome) propul&longs;ion of the Air by <lb/>the &longs;welling <emph type="italics"/>Thorax<emph.end type="italics"/> or <emph type="italics"/>Abdomen<emph.end type="italics"/> into the <lb/>Lungs; &longs;ince upon the bare Dilatation of <lb/>the <emph type="italics"/>Thorax,<emph.end type="italics"/> the Spring of that internal <lb/>Air, or halituous &longs;ub&longs;tance that is wont <pb xlink:href="013/01/370.jpg" pagenum="340"/>to po&longs;&longs;e&longs;s as much of the Cavity of the <lb/>Che&longs;t as the Lungs fill not up, being much <lb/>weaken'd, the external and contiguous <lb/>Air mu&longs;t nece&longs;&longs;arily pre&longs;s in at the open <lb/>Winde-Pipe into the Lungs, as finding <lb/>there le&longs;s re&longs;i&longs;tance then any where el&longs;e a­<lb/>bout it. </s></p><p type="main"> <s>And hence (by the way) we may derive <lb/>a new a&longs;&longs;i&longs;tance to judge of that famous <lb/>Controver&longs;ie di&longs;puted among Naturali&longs;ts <lb/>and Phy&longs;itians, ever &longs;ince <emph type="italics"/>Galens<emph.end type="italics"/> time, <lb/>&longs;ome maintaining that the Che&longs;t, with the <lb/>contained Lungs, may be re&longs;embled to a <lb/>pair of Bellows, which comes therefore <lb/>to be fill'd becau&longs;e it was dilated: And o­<lb/>thers pleading to have the compari&longs;on <lb/>made to a Bladder, which is therefore di­<lb/>lated becau&longs;e it is fill'd. </s> <s>For as to the <lb/><emph type="italics"/>Thorax,<emph.end type="italics"/> it &longs;eems evident from what has <lb/>been lately &longs;aid, that it, like a pair of Bel­<lb/>lows, happens to be partly fill'd with Air, <lb/>but becau&longs;e it was dilated: But as for the <lb/>Lungs them&longs;elves, who want Fibres to <lb/>di&longs;tend them, they may fitly enough be <lb/>compar'd to a Bladder; &longs;ince they are di­<lb/>lated by being fill'd, namely, by that Air <lb/>which ru&longs;hes into them upon the dilatation <lb/>of the Che&longs;t, in who&longs;e increa&longs;ed Cavity <lb/>it findes (as we fre&longs;hly noted) le&longs;s re&longs;i&longs;t-<pb xlink:href="013/01/371.jpg" pagenum="341"/>ance to its Spring then el&longs;ewhere. </s> <s>And <lb/>this brings into my minde that &longs;trange <lb/>Ob&longs;ervation of <emph type="italics"/>Nicolaus Fontanus,<emph.end type="italics"/> a Phy­<lb/><arrow.to.target n="marg58"/><lb/>&longs;itian at <emph type="italics"/>Am&longs;terdam,<emph.end type="italics"/> who te&longs;tifies, That <lb/>in a Boy of the &longs;ame Town, four years <lb/>old, there was found, in&longs;tead of Lungs, a <lb/>certain Membranous Bladder; which be­<lb/>ing fill'd with Wind, and furni&longs;h'd with <lb/>little Veins, had its origination from the <lb/>Wind-Pipe it &longs;elf; which being &longs;uppo&longs;'d <lb/>true, how well it will agree with mo&longs;t of <lb/>the Opinions touching Re&longs;piration, I leave <lb/>to be con&longs;idered. </s></p><p type="margin"> <s><margin.target id="marg58"/><emph type="italics"/>Fontanus ><lb/>apud<emph.end type="italics"/> Bar­<lb/>tholin: lib.<lb/>2. cap. 9.</s></p><p type="main"> <s>And thus may the grand Objection of <lb/><emph type="italics"/>Bartholine,<emph.end type="italics"/> and others, be an&longs;wered: But <lb/>I leave to Anatomi&longs;ts to con&longs;ider what is <lb/>to be &longs;aid to &longs;ome Ob&longs;ervations that &longs;eem <lb/>to contradict tho&longs;e Anatomical Experi­<lb/>ments already mention'd: Such was par­<lb/>ticularly that which I remember I have <lb/>read in <emph type="italics"/>Sennertus<emph.end type="italics"/> (from the ob&longs;ervation of <lb/>his Father-in-law <emph type="italics"/>Schato<emph.end type="italics"/>) of a Melancho­<lb/>ly Student, who having &longs;tabb'd him&longs;elf, <lb/>and pierced the <emph type="italics"/>Diaphragme<emph.end type="italics"/> in the thinner <lb/>or tendonous part (call'd by many the <lb/>Nervous Circle) lived &longs;even Moneths af­<lb/>ter he had &longs;o wounded him&longs;elf, though af­<lb/>ter his death (preceded by violent Vomit-<pb xlink:href="013/01/372.jpg" pagenum="342"/>ings) the Wound (perchance dilated by <lb/>tho&longs;e &longs;trainings) appear'd &longs;o great, that <lb/>the whole Stomack was found to have got <lb/>in by it into the left &longs;ide of the <emph type="italics"/>Thorax.<emph.end type="italics"/><lb/>And &longs;uch al&longs;o was the accident that hap­<lb/>pen'd to a Noble Man, whom I remem­<lb/>ber I have &longs;een, and who is yet alive, in <lb/>who&longs;e Che&longs;t there has, for the&longs;e many <lb/>years, remain'd a hole &longs;o great, that the <lb/>motion of his Heart may be perceiv'd by <lb/>it. </s> <s>The&longs;e (I &longs;ay) and &longs;ome other Ob&longs;er­<lb/>vations, I &longs;hall now forbear to in&longs;i&longs;t on, <lb/>becau&longs;e I hold it not unfit, before we <lb/>come to con&longs;ider the u&longs;e of Re&longs;piration, <lb/>that we acquaint Your Lord&longs;hip with an <lb/>Ingenious Conjecture, that was made at <lb/>the cau&longs;e of the ha&longs;ty death of the Ani­<lb/>mals our Engine kill'd: namely, That it <lb/>was not the want of Air that de&longs;troy'd <lb/>them, but the Pre&longs;&longs;ure of the innate Air <lb/>in the cavity of the Che&longs;t; as if the <lb/>Spring of this Air being no longer coun­<lb/>terballanc'd by the ambient Air, was there­<lb/>by become &longs;o &longs;trong, that it kept the <lb/><emph type="italics"/>Thorax<emph.end type="italics"/> forcibly di&longs;tended, and hinder'd its <lb/>wonted contraction; and &longs;o compre&longs;&longs;'d <lb/>the Lungs and their Ve&longs;&longs;els, as to ob&longs;truct <lb/>the Circulation of the Blood. </s> <s>And this <pb xlink:href="013/01/373.jpg" pagenum="343"/>Conjecture, as it is &longs;pecious enough, &longs;o I <lb/>might have admitted it for true; but that <lb/>I con&longs;ider'd, that (not to mention that <lb/>one, e&longs;pecially of the Animals kill'd in <lb/>our Engine, &longs;eem'd manife&longs;tly for a pret­<lb/>ty while, and not long before he dy'd, to <lb/>move his <emph type="italics"/>Thorax,<emph.end type="italics"/> as if he exerci&longs;'d Re&longs;pi­<lb/>ration) the diligent <emph type="italics"/>Wallæus<emph.end type="italics"/> relates, That <lb/>he divers times ob&longs;erv'd, in the Di&longs;&longs;ecti­<lb/>on of live Bodies, that the Membrane <lb/>that inve&longs;ts the Lungs, had Pores in it <lb/>as big as the larger &longs;ort of Peas, which a­<lb/>grees with the Ob&longs;ervations of Chyrur­<lb/>gions and Phy&longs;itians, <emph type="italics"/>viz.<emph.end type="italics"/></s><s> That matter <lb/>collected in the <emph type="italics"/>Thorax,<emph.end type="italics"/> has penetrated in­<lb/>to the Lungs, and been di&longs;charged by <lb/>coughing. </s> <s>And I remember too, that mo&longs;t <lb/>of the Animals we kill'd in our Engine <lb/>were Birds, of who&longs;e Lungs <emph type="italics"/>Harvey<emph.end type="italics"/><lb/>&longs;omewhere informs us, That he ob­<lb/>&longs;erv'd them very manife&longs;tly to open at <lb/>their Extremities into the <emph type="italics"/>Abdomen.<emph.end type="italics"/><lb/>And by &longs;uch Perforations we may well <lb/>&longs;uppo&longs;e the pa&longs;&longs;age free betwixt the exter­<lb/>nal Air and that in the <emph type="italics"/>Abdomen:<emph.end type="italics"/> But this <lb/>Conjecture may be further con&longs;ider'd. <lb/></s> <s>Be&longs;ides, to &longs;how that the Animals that <lb/>died in our Gla&longs;&longs;es, need not be &longs;uppo&longs;'d <pb xlink:href="013/01/374.jpg" pagenum="344"/>to have been kill'd by the want of Air, we <lb/>fore&longs;ee another Argument that we mu&longs;t <lb/>deal &longs;o ingeniou&longs;ly with Your Lord&longs;hip, <lb/>as not to conceal. </s> <s>You very well know, <lb/>that be&longs;ides the generality of the <lb/>Schools, there are many new Philo&longs;ophers <lb/>who, though they di&longs;&longs;ent from the old <lb/>Peripateticks in other things, do, as they, <lb/>deny the po&longs;&longs;ibility of a <emph type="italics"/>Vacuum;<emph.end type="italics"/> and <lb/>hold, that tho&longs;e &longs;paces which are devoid <lb/>of Air, and other gro&longs;&longs;er Bodies, are all <lb/>of them exactly repleni&longs;hed with a certain <lb/>Etherial Matter, &longs;o thin and &longs;ubtle, that <lb/>it can freely permeate the Pores of the <lb/>compacted&longs;t and clo&longs;e&longs;t Bodies, and ev'n <lb/>of Gla&longs;s it &longs;elf. </s> <s>Now &longs;ome of tho&longs;e Na­<lb/>turali&longs;ts that are of this per&longs;wa&longs;ion may <lb/>object, That the Animals that died in our <lb/>Receivers, did &longs;o, not &longs;o much for lack of <lb/>Air, as by rea&longs;on that the Air that was <lb/>pump'd out was nece&longs;&longs;arily &longs;ucceeded by <lb/>an Etherial Sub&longs;tance; which con&longs;i&longs;ting of <lb/>parts vehemently agitated, and &longs;o very <lb/>&longs;mall, as without re&longs;i&longs;tance to pa&longs;s in and <lb/>out through the very Pores of Gla&longs;s; it <lb/>may well be &longs;uppo&longs;'d, that a con&longs;iderable <lb/>quantity of this re&longs;tle&longs;s and &longs;ubtle Mat­<lb/>ter, meeting together in the Receiver, <pb xlink:href="013/01/375.jpg" pagenum="345"/>with the exce&longs;&longs;ive heat of it, may be <lb/>quickly able to de&longs;troy a little Animal, or <lb/>at lea&longs;t, make the Air too intemperately <lb/>hot to be fit for Re&longs;piration. </s></p><p type="main"> <s>But though this be a Difficulty not &longs;o <lb/>ea&longs;ily to be re&longs;olv'd without the a&longs;&longs;i&longs;tance <lb/>of our Engine, yet I &longs;uppo&longs;e we have al­<lb/>ready an&longs;wer'd the Objection by our 38<emph type="sup"/>th<emph.end type="sup"/><lb/>and 39<emph type="sup"/>th<emph.end type="sup"/> Experiments; which though we <lb/>made partly for other purpo&longs;es, yet we <lb/>premi&longs;'d them onely to clear up the diffi­<lb/>culty propo&longs;'d. </s></p><p type="main"> <s>Another &longs;u&longs;pition we &longs;hould have en­<lb/>tertain'd concerning the death of our Ani­<lb/>mals, namely, That upon the &longs;udden re­<lb/>moval of the wonted pre&longs;&longs;ure of the am­<lb/>bient Air, the warm Blood of tho&longs;e Ani­<lb/>mals was brought to an Efferve&longs;cence or <lb/>Ebullition, or at lea&longs;t &longs;o vehemently ex­<lb/>panded, as to di&longs;turb the Circulation of <lb/>the Blood, and &longs;o di&longs;order the whole Oe­<lb/>conomy of the Body. (This (I &longs;ay) I <lb/>&longs;hould have had &longs;ome &longs;u&longs;pition of) but <lb/>that Animals of a hot Con&longs;titution are <lb/>not the &longs;ole ones that cannot in our ex­<lb/>hau&longs;ted Engine exerci&longs;e the Function of <lb/>Life. </s> <s>But I mu&longs;t not now dwell upon <lb/>matters of this nature, becau&longs;e I think <lb/>it high time to proceed to the con&longs;iderati-<pb xlink:href="013/01/376.jpg" pagenum="346"/>on of the principal &longs;ubject of our Engine, <lb/>namely, The u&longs;e of Re&longs;piration; or ra­<lb/>ther, The u&longs;e of the Air in Re&longs;piration. <lb/></s> <s>For whereas of the divers u&longs;es of it men­<lb/>tion'd by Anatomi&longs;ts the mo&longs;t, &longs;uch as <lb/>the Production and Modulation of the <lb/>Voice by the Eli&longs;ion of the Air, the <emph type="italics"/>La­<lb/>rynx<emph.end type="italics"/> &c. </s> <s>the expul&longs;ion of Excrements <lb/>by Coughing, the conveying in of Odours <lb/>by In&longs;piration, and &longs;ome others, rather <lb/>convenient for the well being of an Ani­<lb/>mal, then ab&longs;olutely nece&longs;&longs;ary to his Life: <lb/>Whereas (I &longs;ay) the other u&longs;es are &longs;uch as <lb/>we have &longs;aid, The great <emph type="italics"/>Hippocrates<emph.end type="italics"/> him­<lb/>&longs;elf gives this notable Te&longs;timony to the <lb/>u&longs;e of the Air, as to Animals endow'd <lb/>with Lungs, <emph type="italics"/>Mortalibus<emph.end type="italics"/> (&longs;ays he) <emph type="italics"/>hic<emph.end type="italics"/> (&longs;pi­<lb/>ritus) <emph type="italics"/>tum vitæ, tum morborum ægrotis cau­<lb/>&longs;a e&longs;t. </s> <s>Tantáque corporibus omnibus &longs;pi­<lb/>ritûs ine&longs;t neceßitas, ut &longs;iquidem aliis om­<lb/>nibus & cibis & potionibus, quis ab&longs;tineat, <lb/>duos <expan abbr="tam&etilde;">tamen</expan> aut tres, vel plures dies poßit vi­<lb/>tam ducere: At &longs;i quis &longs;piritus in corpus <lb/>vias intercipiat, vel exiguâ diei parte, ho­<lb/>mini pereundum &longs;it; Adeo nece&longs;&longs;arius e&longs;t <lb/>u&longs;us &longs;piritûs in corpore. </s> <s>Ad hæc quo&queacute;, <lb/>quum omnibus aliis actionibus homines qui­<lb/>e&longs;cant, quod mutationibus innumer is vita <lb/>&longs;it expo&longs;ita, ab hâc tamen &longs;olâ actione nun-<emph.end type="italics"/><pb xlink:href="013/01/377.jpg" pagenum="347"/><emph type="italics"/>quam de&longs;i&longs;tant animantia, quin aut &longs;piritum <lb/>adducant, aut reddant.<emph.end type="italics"/></s></p><p type="main"> <s>But touching the account upon which <lb/>the In&longs;piration and Ex&longs;piration of Air <lb/>(both which are comprehended in <foreign lang="greek">a)gapno<gap/></foreign>, <lb/>Re&longs;piration) is &longs;o nece&longs;&longs;ary to Life, both <lb/>Naturali&longs;ts and Phy&longs;itians do &longs;o di&longs;agree, <lb/>that it will be very difficult either to re­<lb/>concile their Opinions, or determine their <lb/>Controver&longs;ies. </s></p><p type="main"> <s>For fir&longs;t, Many there are who think <lb/>the chief (if not &longs;ole) u&longs;e of Re&longs;piration <lb/>to be the Cooling and tempering of that <lb/>Heat in the Heart and Blood, which other­<lb/>wi&longs;e would be immoderate: And this O­<lb/>pinion, not onely &longs;eems to be mo&longs;t recei­<lb/>ved among&longs;t Schola&longs;tick Writers, but di­<lb/>vers of the new Philo&longs;ophers, Carte&longs;ians, <lb/>and others, admitted with &longs;ome variation; <lb/>teaching, That the Air is nece&longs;&longs;ary, by its <lb/>coldne&longs;s, to conden&longs;e the Blood that pa&longs;­<lb/>&longs;es out of the right Ventricle of the <lb/>Heart into the Lungs, that thereby it may <lb/>obtain &longs;uch a con&longs;i&longs;tence, as is requi&longs;ite <lb/>to make it fit Fewel for the vital Fire or <lb/>Flame, in the left Ventricle of the heart. <lb/></s> <s>And this Opinion &longs;eems favor'd by this, <lb/>That Fi&longs;hes, and other cold Creatures, <lb/>who&longs;e Hearts have but one cavity, are al-<pb xlink:href="013/01/378.jpg" pagenum="348"/>&longs;o unprovided of Lungs, and by &longs;ome o­<lb/>ther con&longs;iderations. </s> <s>But though it need <lb/>not be deny'd, that the in&longs;pir'd Air may <lb/>&longs;ometimes be of u&longs;e by refrigerating the <lb/>Heart; yet (again&longs;t the Opinion that makes <lb/>this Refrigeration, the mo&longs;t genuine and <lb/>con&longs;tant u&longs;e of the Air) it may be Obje­<lb/>cted, That divers cold Creatures (&longs;ome <lb/>of which, as particularly Frogs, live in <lb/>the Water) have yet need of Re&longs;piration, <lb/>which &longs;eems not likely to be needed for <lb/>Refrigeration by them that are de&longs;titute of <lb/>any &longs;en&longs;ible heat, and be&longs;ides, live in the <lb/>cold Water: That even decrepid old <lb/>Men, who&longs;e natural heat is made very <lb/>languid, and almo&longs;t extingui&longs;h'd by rea­<lb/>&longs;on of age, have yet a nece&longs;&longs;ity of fre­<lb/>quent Re&longs;piration: That a temperate Air <lb/>is fitte&longs;t for the generality of breathing <lb/>Creatures; and as an Air too hot, &longs;o al­<lb/>&longs;o an Air too cold, may be inconvenient <lb/>for them (e&longs;pecially, if they be troubled <lb/>with an immoderate degree of the &longs;ame <lb/>Quality which is predominant in the Air:) <lb/>That in &longs;ome Di&longs;ea&longs;es the natural heat is <lb/>&longs;o weaken'd, that in ca&longs;e the u&longs;e of Re&longs;pi­<lb/>ration were to cool, it would be more <lb/>hurtful then beneficial to breath; and the <lb/>&longs;u&longs;pending of the Re&longs;piration, may &longs;up-<pb xlink:href="013/01/379.jpg" pagenum="349"/>ply the place of tho&longs;e very hot Medicines <lb/>that are wont to be employ'd in &longs;uch Di­<lb/>&longs;tempers: That Nature might much bet­<lb/>ter have given the Heart but a moderate <lb/>heat, then &longs;uch an exce&longs;&longs;ive one, as needs <lb/>to be perpetually cool'd, to keep it from <lb/>growing de&longs;tructive; which the gentle, <lb/>and not the burning heat of an Animals <lb/>Heart, &longs;eems not inten&longs;e enough &longs;o indi­<lb/>&longs;pen&longs;ably to require. </s> <s>The&longs;e, and other <lb/>Objections, might be oppo&longs;'d, and pre&longs;&longs;'d <lb/>again&longs;t the recited Opinion: But we &longs;hall <lb/>not in&longs;i&longs;t on them, but onely adde to <lb/>them, That it appears not by our fore­<lb/>going Experiments (I mean the 38<emph type="sup"/>th<emph.end type="sup"/> and <lb/>39<emph type="sup"/>th<emph.end type="sup"/>) that in our exhau&longs;ted Receiver, <lb/>where yet Animals die &longs;o &longs;uddenly for <lb/>want of Re&longs;piration, the ambient Body is <lb/>&longs;en&longs;ibly hotter then the common Air. </s></p><p type="main"> <s>Other Learned Men there are, who will <lb/>have the very &longs;ub&longs;tance of the Air to get <lb/>in by the Ve&longs;&longs;els of the Lungs, to the <lb/>left Ventricle of the Heart, not onely to <lb/>temper its heat, but to provide for the <lb/>generation of Spirits. </s> <s>And the&longs;e alledge <lb/>for them&longs;elves the Authority of the An­<lb/>tients, among whom <emph type="italics"/>Hippocrates<emph.end type="italics"/> &longs;eems <lb/>manife&longs;tly to favor their Opinion; and <lb/>both <emph type="italics"/>Ari&longs;totle<emph.end type="italics"/> and <emph type="italics"/>Galen<emph.end type="italics"/> do &longs;ometimes <pb xlink:href="013/01/380.jpg" pagenum="350"/>(for methinks they &longs;peak doubtfully e­<lb/>nough) appear inclinable to it. </s> <s>But for <lb/>ought ever I could &longs;ee in Di&longs;&longs;ections, it is <lb/>very difficult to make out, how the Air is <lb/>convey'd into the left Ventricle of the <lb/>Heart, e&longs;pecially the <emph type="italics"/>Sy&longs;tole<emph.end type="italics"/> and <emph type="italics"/>Dia&longs;tole<emph.end type="italics"/><lb/>of the Heart and Lungs, being very far <lb/>from being Synchronical: Be&longs;ides, that <lb/>the Spirits &longs;eeming to be but the mo&longs;t <lb/>&longs;ubtle and unctuous Particles of the <lb/>Blood, appear to be of a very differing <lb/>Nature from that of the lean and incom­<lb/>bu&longs;tible Corpu&longs;cles of Air. </s> <s>Other Ob­<lb/>jections again&longs;t this Opinion have been <lb/>propo&longs;'d, and pre&longs;t by that excellent Ana­<lb/>tomi&longs;t, and my Indu&longs;trious Friend, Dr. <lb/><emph type="italics"/>Highmore,<emph.end type="italics"/> to whom I &longs;hall therefore refer <lb/>you. </s></p><p type="main"> <s>Another Opinion there is touching Re­<lb/>&longs;piration, which makes the genuine u&longs;e of <lb/>it to be Ventilation (not of the Heart, <lb/>but) of the Blood, in its pa&longs;&longs;age thorow <lb/>the Lungs; in which pa&longs;&longs;age, it is di&longs;­<lb/>burthened of tho&longs;e Excrementitious <lb/>Steams, proceeding, for the mo&longs;t part, <lb/>from the &longs;uperfluous Sero&longs;ities of the <lb/>Blood, (we may adde) and of the <emph type="italics"/>Chyle<emph.end type="italics"/><lb/>too, which (by tho&longs;e new Conduits of <lb/>late very happily detected by the famous <pb xlink:href="013/01/381.jpg" pagenum="351"/><emph type="italics"/>Pecquet<emph.end type="italics"/>) hath been newly mix'd with it in <lb/>the Heart.) And this Opinion is that of <lb/>the Indu&longs;trious <emph type="italics"/>Mœbius,<emph.end type="italics"/> and is &longs;aid to <lb/>have been that of that excellent Philo&longs;o­<lb/>pher <emph type="italics"/>Ga&longs;&longs;endus;<emph.end type="italics"/> and hath been in part an <lb/>Opinion almo&longs;t vulgar: But this <emph type="italics"/>Hypo­<lb/>the&longs;is<emph.end type="italics"/> may be explicated two ways: For <lb/>fir&longs;t, The nece&longs;&longs;ity of the Air in Re&longs;pi­<lb/>ration, may be &longs;uppo&longs;'d to proceed from <lb/>hence; That as a Flame cannot long burn <lb/>in a narrow and clo&longs;e place, becau&longs;e the <lb/>Fuliginous Steams it unce&longs;&longs;antly throws <lb/>out, cannot be long receiv'd into the am­<lb/>bient Body; which after a while growing <lb/>too full of them, to admit any more, &longs;ti­<lb/>fles the flame, &longs;o that the vital Fire in the <lb/>Heart requires an ambient Body, of a <lb/>yielding nature, to receive into it the &longs;u­<lb/>perfluous Sero&longs;ities and other Recrements <lb/>of the Blood, who&longs;e &longs;ea&longs;onable Expul&longs;i­<lb/>on is requi&longs;ite to depurate the Ma&longs;s of <lb/>Blood, and make it fit both to Circulate; <lb/>and to maintain the vital heat re&longs;iding in <lb/>the Heart. </s> <s>The other way of explicating <lb/>the above-mention'd <emph type="italics"/>Hypothe&longs;is,<emph.end type="italics"/> is, by <lb/>&longs;uppo&longs;ing, that the Air does not onely, as <lb/>a Receptacle, admit into its Pores the Ex­<lb/>crementitious vapors of the Blood, when <lb/>they are expell'd through the Wind-Pipe, <pb xlink:href="013/01/382.jpg" pagenum="352"/>but does al&longs;o convey them out of the <lb/>Lungs, in regard that the in&longs;pired Air, <lb/>reaching to all the ends of the <emph type="italics"/>A&longs;pera Ar­<lb/>teria,<emph.end type="italics"/> does there a&longs;&longs;ociate it &longs;elf with the <lb/>Exhalations of the circulating Blood, and <lb/>when tis exploded, carrys them away with <lb/>it &longs;elf, as we &longs;ee that winds &longs;peedily dry up <lb/>the &longs;urfaces of wet Bodies, not to &longs;ay any <lb/>thing of what we formerly ob&longs;ervd touch­<lb/>ing our Liquor, who&longs;e fumes were &longs;trange­<lb/>ly elevated upon the Ingre&longs;s of the Air. </s></p><p type="main"> <s>Now of the&longs;e two ways of explicating <lb/>the u&longs;e of Re&longs;piration, our Engine af­<lb/>fords us this Objection again&longs;t the fir&longs;t; <lb/>That upon the Ex&longs;uction of the Air, the <lb/>Animals die a great deal &longs;ooner then if it <lb/>were left in the Ve&longs;&longs;el; though by that <lb/>Ex&longs;uction the ambient &longs;pace is left much <lb/>more free to receive the &longs;teams that are ei­<lb/>ther breathed out of the Lungs of the <lb/>Animal, or di&longs;charg'd by in&longs;en&longs;ible Tran­<lb/>&longs;piration through the Pores of his <lb/>Skin. </s></p><p type="main"> <s>But if the <emph type="italics"/>Hypothe&longs;is<emph.end type="italics"/> propo&longs;'d, be taken <lb/>in the other &longs;en&longs;e, it &longs;eems congruous e­<lb/>nough to that grand ob&longs;ervation, which <lb/>partly the <emph type="italics"/>Phænomena<emph.end type="italics"/> of our Engine, and <lb/>partly the relations of Travellers, have <lb/>&longs;ugge&longs;ted to us, namely, That there is a <pb xlink:href="013/01/383.jpg" pagenum="353"/>certain con&longs;i&longs;tence of Air requi&longs;ite to Re­<lb/>&longs;piration; &longs;o that if it be too thick, and <lb/>already over-charged with vapors, it will <lb/>be unfit to unite with, and carry off tho&longs;e <lb/>of the Blood, as Water will di&longs;&longs;olve, and <lb/>a&longs;&longs;ociate to it &longs;elf but a certain proportion <lb/>of &longs;aline Corpu&longs;cles; and if it be too <lb/>thin or rarefied, the number or &longs;ize of the <lb/>Aërial Particles is too &longs;mall to be able to <lb/>a&longs;&longs;ume and carry off the halituous Excre­<lb/>ments of the Blood, in &longs;uch plenty as is <lb/>requi&longs;ite. </s></p><p type="main"> <s>Now that Air too much thicken'd (and <lb/>as it were clogg'd) with Steams, is unfit <lb/>for Re&longs;piration, may appear by what is <lb/>wont to happen in the Lead-Mines of <emph type="italics"/>De­<lb/>von&longs;hire,<emph.end type="italics"/> (and, for ought I know, in tho&longs;e <lb/>too of other Countrys, though I have <lb/>&longs;een Mines where no &longs;uch thing was com­<lb/>plain'd of) for I have been inform'd by <lb/>more then one credible Per&longs;on (and parti­<lb/>cularly by an Ingenious Man, that has of­<lb/>ten, for curio&longs;ity, digg'd in tho&longs;e Mines, <lb/>and been imploy'd about them) that there <lb/>often ri&longs;es Damps, as retaining the <emph type="italics"/>Ger­<lb/>mane<emph.end type="italics"/> Word by which they call them) <lb/>which does &longs;o thicken the Air, that unle&longs;s <lb/>the Work-men &longs;peedily make &longs;igns to <lb/>them that are above, they would (which <pb xlink:href="013/01/384.jpg" pagenum="354"/>al&longs;o &longs;ometimes happens) be pre&longs;ently <lb/>&longs;tifled for want of Breath; and though <lb/>their Companions do make ha&longs;te to draw <lb/>them up, yet frequently, by that time <lb/>they come to the free Air, they are, as it <lb/>were, in a &longs;woon, and are a good while be­<lb/>fore they come to them&longs;elves again. </s> <s>And <lb/>that this &longs;wooning &longs;eems not to proceed <lb/>from any Ar&longs;enical or Poy&longs;onous Exhala­<lb/>tion contain'd in the Damp, as from its <lb/>over-much conden&longs;ing the Air, &longs;eems pro­<lb/>bable from hence; That the &longs;ame Damps <lb/>oftentimes lei&longs;urely extingui&longs;h the flames <lb/>of their Candles or Lamps; and from <lb/>hence al&longs;o that it appears (by many Rela­<lb/>tions of Authentical Authors) that in <lb/>tho&longs;e Cellars where great &longs;tore of new <lb/>Wine is &longs;et to work, men have been &longs;uffo­<lb/>cated by the too great plenty of the &longs;teams <lb/>exhaling from the Mu&longs;t, and too much <lb/>thickning the Air: as may be gathered <lb/>from the cu&longs;tom that is now u&longs;ed in &longs;ome <lb/>hot Countrys, where tho&longs;e that have oc­<lb/>ca&longs;ion to go into &longs;uch Cellars, carry with <lb/>them a quantity of well kindled Coals, <lb/>which they hold near their Faces; where­<lb/>by it comes to pa&longs;s, that the Fire di&longs;cu&longs;­<lb/>&longs;ing the Fumes, and rarefying the Air re­<lb/>duces the ambient Body to a con&longs;i&longs;tence fit <lb/>for Re&longs;piration.</s></p> <pb xlink:href="013/01/385.jpg" pagenum="355"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/386.jpg" pagenum="356"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/387.jpg" pagenum="357"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/388.jpg" pagenum="358"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/389.jpg" pagenum="359"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/390.jpg" pagenum="360"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/391.jpg" pagenum="361"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/392.jpg" pagenum="362"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/393.jpg" pagenum="363"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/394.jpg" pagenum="364"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/395.jpg" pagenum="365"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/396.jpg" pagenum="366"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/397.jpg" pagenum="367"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/398.jpg" pagenum="368"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/399.jpg" pagenum="369"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/400.jpg" pagenum="370"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/401.jpg" pagenum="371"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/402.jpg" pagenum="372"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/403.jpg" pagenum="373"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/404.jpg" pagenum="374"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/405.jpg" pagenum="375"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/406.jpg" pagenum="376"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/407.jpg" pagenum="377"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/408.jpg" pagenum="378"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/409.jpg" pagenum="379"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/410.jpg" pagenum="380"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/411.jpg" pagenum="381"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/412.jpg" pagenum="382"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/413.jpg" pagenum="383"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/414.jpg" pagenum="384"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/415.jpg" pagenum="385"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/416.jpg" pagenum="386"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/417.jpg" pagenum="387"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/418.jpg" pagenum="388"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/419.jpg" pagenum="389"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/420.jpg" pagenum="390"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/421.jpg" pagenum="391"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/422.jpg" pagenum="392"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/423.jpg" pagenum="393"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/424.jpg" pagenum="394"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/425.jpg" pagenum="395"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/426.jpg" pagenum="396"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/427.jpg" pagenum="397"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/428.jpg" pagenum="398"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/429.jpg" pagenum="399"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/430.jpg" pagenum="400"/><p><s>page not transcribed</s></p> <pb xlink:href="013/01/431.jpg" pagenum="401"/><p><s>page not transcribed</s></p> </chap> </body> <back/> </text></archimedes>