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</info> <text> <front> </front> <body> <chap> <pb/>

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<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><pb/><pb/>

<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>

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<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>

<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><figure></figure>

<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><pb/><pb/><figure></figure>

<s><emph type="center"/>To the Reader.<emph.end type="center"/></s>

<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>

<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/><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><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 n<gap/>w 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>

<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/><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>

<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>

<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/><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><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/><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>

<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>

<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>

<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/>do<gap/> 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><pb/>

<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>

<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/><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><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>

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<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>

<s><emph type="italics"/>I need not perhaps repre&longs;ent to the equi-<emph.end type="italics"/><pb/><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><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>

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<s><emph type="italics"/>But if it be demanded, why then I did <lb/>not make it f<gap/>ter 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/><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>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>

<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/><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><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/><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>

<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>

<s>Friendly Reader, </s>

<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/><emph type="italics"/>the newer French Dre&longs;s.<emph.end type="italics"/></s>

<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>

<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><pb/>

<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/><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>

<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>

<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/><emph type="italics"/>in the Mines of Wi&longs;dome.<emph.end type="italics"/></s>

<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>

<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>

<s><emph type="italics"/>I de&longs;ire to be excu&longs;ed that I<emph.end type="italics"/><pb/><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><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>

<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>

Line 103

<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>

<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><pb/>

<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>

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<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>

<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><pb/>

<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>

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<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>

<s><emph type="italics"/>The &longs;ixteenth Experiment, concerning the <lb/>operation of the Load&longs;tone.<emph.end type="italics"/> 105, &c. </s><pb/>

<s><emph type="italics"/>The &longs;ixteenth Experiment, concerning the <lb/>operation of the Load&longs;tone.<emph.end type="italics"/> 105, &c. </s><pb xlink:href="013/01/026.jpg"/>

<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>

<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/><emph type="italics"/>thereof.<emph.end type="italics"/> 129 &c. </s>

<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>

<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>

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<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>

<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/><emph type="italics"/>common and di&longs;till'd Water.<emph.end type="italics"/> 182 </s>

<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>

<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>

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<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>

<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><pb/>

<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>

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<s>The Diameter of it, <lb/>and the weight it &longs;u&longs;tain'd.<emph.end type="italics"/> 233 &c. </s>

<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><pb/>

<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>

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<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/><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>

<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>

<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/><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>

<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>

<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;<gap/>lfe,) <lb/>propo&longs;'d upon the Con&longs;ideration of divers admirable <lb/>effects wrought thereby.<emph.end type="italics"/> 320 &c. </s>

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<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>

<s><emph type="italics"/>The Conclu&longs;ion.<emph.end type="italics"/> 394 <pb/><pb/><figure id="fig2"></figure><pb/><figure id="fig3"></figure><pb/><figure id="fig4"></figure><pb/><figure id="fig5"></figure></s><pb/><pb/><pb/><pb pagenum="1"/><figure></figure>

<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><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"/>

<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>

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<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 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"/>Torricell<gap/>s:<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>

<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"/>Torricell<gap/>s:<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>

<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 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>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 <gap/>in, 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>

<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 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>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>

<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>

<s><arrow.to.target n="marg1"></arrow.to.target><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 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><arrow.to.target n="marg1"></arrow.to.target><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 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>

<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>

Line 237

<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 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/>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 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>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>

<s>To give your Lord&longs;hip then, in the <lb/>fir&longs;t place, &longs;ome account of the Engine it <pb 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>

<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>

<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>

Line 253

<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>

<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 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>

<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>

<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 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>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>

<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 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>

<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>

<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>

<s>The Pump con&longs;i&longs;ts of four parts, a <pb pagenum="13"/>hollow Cylindre, a Sucker, a handle to <lb/>move that Sucker, and a Valve. </s>

<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>

<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>

<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 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>

<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>

<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>

<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>

<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 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>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 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>

<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>

<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 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 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>

<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 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>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>

<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 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>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>

<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><pb pagenum="20"/>

<s>TO proceed now to the <emph type="italics"/>Phænomena,<emph.end type="italics"/><lb/><arrow.to.target n="marg2"></arrow.to.target><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>

Line 317

<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 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>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><pb pagenum="22"/>

<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><pb pagenum="23"/>

<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>

Line 335

<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 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>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>

<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 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><pb pagenum="26"/>

<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><pb xlink:href="013/01/066.jpg" pagenum="26"/>

<s>By the&longs;e two differing ways, my Lord, <lb/>may the Spring of the Air be explicated. <lb/></s>

Line 349

<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 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>

<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>

<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>

Line 357

<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 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>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 pagenum="29"/>Recent A&longs;tronomers, who &longs;eem willing <lb/>to enlarge its bounds as much as they dare, <lb/>does reach. </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>

<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 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>

<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>

<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 t<gap/> number of <lb/>miles. </s>

<s>And the diligent and learned <pb 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>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>

<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 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 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 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>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>

<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 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>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 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>

<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>

<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"></arrow.to.target><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 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>

<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"></arrow.to.target><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>

<s><margin.target id="marg3"></margin.target><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>

<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 pagenum="37"/>to divers ingenious per&longs;ons has at fir&longs;t <lb/>&longs;ight &longs;eem'd very wonderful. </s>

<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>

<s>THe thing that is wont to be admired, <lb/><arrow.to.target n="marg4"></arrow.to.target><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 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>

<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>

<s><margin.target id="marg4"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 2.</s>

<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 pagenum="39"/>&longs;topple may be lifted up without any dif<lb/>ficulty at all. </s>

<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>

<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 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>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 pagenum="41"/>&longs;ure of the outward again&longs;t the &longs;ame Gla&longs;s. <lb/></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><pb pagenum="42"/>

<s>WE will now proceed to ob&longs;erve that <lb/><arrow.to.target n="marg5"></arrow.to.target><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 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>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 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>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 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>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>

Line 445

<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 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>

<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>

<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><pb pagenum="47"/>

<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>

<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 pagenum="48"/>and &longs;eem'd to lift up the Bladder it <lb/>&longs;elf. </s>

<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>

<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>

<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 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>

<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>

<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>

<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>

<s>TO try then at once both what it was <lb/><arrow.to.target n="marg7"></arrow.to.target><lb/>that expanded the Bladder, and what <lb/>a powerful Spring there is ev'n in the Air <pb 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>TO try then at once both what it was <lb/><arrow.to.target n="marg7"></arrow.to.target><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>

Line 469

<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>

<s>But, to verifie what we &longs;ay in another <lb/>Di&longs;cour&longs;e, where we &longs;how, That even <pb 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 pagenum="52"/>blown in, could get out of them, but by <lb/>violently breaking them. </s>

<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>

<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>

<s>HAving thus &longs;een that the Air has an <lb/><arrow.to.target n="marg8"></arrow.to.target><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 pagenum="53"/>parcel of Air might by this its own Spring <lb/>be dilated. </s>

<s>HAving thus &longs;een that the Air has an <lb/><arrow.to.target n="marg8"></arrow.to.target><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>

<s><margin.target id="marg8"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 6.</s>

<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 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>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 pagenum="55"/>ally &longs;uppo&longs;ing the dilatation not to be re<lb/>&longs;train'd by the Bladder. </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>

<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>

<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><pb pagenum="56"/>

<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>

Line 501

<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 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>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>

Line 509

<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 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>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 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>

<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>

<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 pagenum="60"/>nothing but the ordinary pre&longs;&longs;ure of the <lb/>contiguous Air. </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>

<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 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>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 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>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>

Line 533

<s><margin.target id="marg9"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 7.</s>

<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 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>

Line 541

<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>

<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><pb pagenum="64"/>

<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><pb xlink:href="013/01/104.jpg" pagenum="64"/>

<s>WE took a Gla&longs;s Helmet or Alem<lb/><arrow.to.target n="marg10"></arrow.to.target><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 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>

<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>

<s><margin.target id="marg10"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 8.</s>

<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><pb pagenum="66"/>

<s>WE took a Gla&longs;s Viol able to hold <lb/><arrow.to.target n="marg11"></arrow.to.target><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>

<s><margin.target id="marg11"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 9.</s>

<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 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>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>

<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 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 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 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>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>

<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 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>

<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>

<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>

<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 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 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>

Line 587

<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 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>

<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>

<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>

<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 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>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>

<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 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>

<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>

<s>WE took a Tallow-Candle of &longs;uch <lb/><arrow.to.target n="marg12"></arrow.to.target><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>

Line 605

<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 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>

<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>

<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>

<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 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>

Line 617

<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 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>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 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>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>

<s>THere was taken a Wier, which being <lb/><arrow.to.target n="marg13"></arrow.to.target><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 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>

<s>THere was taken a Wier, which being <lb/><arrow.to.target n="marg13"></arrow.to.target><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>

<s><margin.target id="marg13"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 11.</s>

<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 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>

<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>

<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>

<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 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>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 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>

<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>

<s>BEing willing to try after this &longs;ome<lb/><arrow.to.target n="marg14"></arrow.to.target><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 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>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><pb pagenum="84"/>

<s><margin.target id="marg14"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 12.</s>

Line 663

<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>

<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 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>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 pagenum="86"/>and pa&longs;t the po&longs;&longs;ibility of being recover'd <lb/>by the re-admitted Air. </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>

<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>

Line 675

<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>

<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 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>

<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>

<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 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>

<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>

<s>TO try diver&longs;e things at once, <lb/><arrow.to.target n="marg16"></arrow.to.target><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 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>TO try diver&longs;e things at once, <lb/><arrow.to.target n="marg16"></arrow.to.target><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 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>

<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>

<s><margin.target id="marg16"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 14.</s>

<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><pb pagenum="101"/>

<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>

Line 703

<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 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>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>

Line 713

<s><margin.target id="marg17"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 15.</s>

<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 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>

<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>

<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 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>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 pagenum="105"/>tion'd divers of my Thoughts and Expe<lb/>riments concerning Fire. </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>

<s>WE de&longs;igned to try whether or no <lb/><arrow.to.target n="marg18"></arrow.to.target><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 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>

<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>

<s><margin.target id="marg18"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 16</s>

<s>PRoceed we now to the mention of <lb/><arrow.to.target n="marg19"></arrow.to.target><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 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>

Line 745

<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 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 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>

<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>

<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 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>

<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>

<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 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>

<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>

<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 pagenum="112"/>of the &longs;urface of that in the Ve&longs;&longs;el. </s>

<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>

<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>

Line 763

<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 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>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>

Line 771

<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 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, b<gap/>ng &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>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, b<gap/>ng &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>

<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 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>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>

<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 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>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 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>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 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>

<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>

<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>

<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 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>

<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>

<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><pb pagenum="120"/>

<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>

<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>

<s>But on the other &longs;ide it may be &longs;aid, <pb 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>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><pb pagenum="122"/>

<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 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>

<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>

<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>

<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 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>

<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>

<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="fo&utilde;d">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 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>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 pagenum="126"/>to think by &longs;everal Circum&longs;tances. </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>

<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 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>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 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>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 pagenum="129"/>&longs;elf, does le&longs;s potently pre&longs;s upon the &longs;ub<lb/>jacent Mercury. </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>

<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>

Line 847

<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 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>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>

Line 855

<s><margin.target id="marg20"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 18.</s>

<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 pagenum="131"/>the heat or cold that affected the ambient <lb/>Air. </s>

<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 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 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 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><pb pagenum="134"/>

<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>

<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 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>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>

<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><pb pagenum="136"/>

<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>

Line 887

<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 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 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 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>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>

<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 en<gap/>ea&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 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>

Line 903

<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 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>

<s>THe &longs;ame Rea&longs;on that mov'd us to <lb/><arrow.to.target n="marg21"></arrow.to.target><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 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>

<s>THe &longs;ame Rea&longs;on that mov'd us to <lb/><arrow.to.target n="marg21"></arrow.to.target><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>

<s><margin.target id="marg21"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 19.</s>

<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><pb pagenum="142"/>

<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>

Line 921

<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 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 <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>

<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><pb pagenum="144"/>

<s>THat the Air has a notable Ela&longs;tical <lb/><arrow.to.target n="marg22"></arrow.to.target><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>

Line 935

<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 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>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>

<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 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>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 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>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>

<s>TO di&longs;cover whether the Expan&longs;ion <lb/><arrow.to.target n="marg23"></arrow.to.target><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 pagenum="148"/>&longs;ub&longs;tance &longs;ubtler then it &longs;elf, re&longs;iding m<lb/>it. </s>

<s>TO di&longs;cover whether the Expan&longs;ion <lb/><arrow.to.target n="marg23"></arrow.to.target><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 <gap/>'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>

Line 959

<s><margin.target id="marg23"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 21.</s>

<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 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>

<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>

<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 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 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><pb pagenum="151"/>

<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>

<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 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>

<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>

<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>

<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 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>

<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>

<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>

<s>Hence likewi&longs;e we may verifie what we <lb/>ob&longs;erv'd at the clo&longs;e of the foregoing <pb 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>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>

<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 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>

<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>

<s>WE recited in our nineteenth Ex<lb/>periment, how by drawing mo&longs;t <lb/><arrow.to.target n="marg24"></arrow.to.target><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 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>

<s>WE recited in our nineteenth Ex<lb/>periment, how by drawing mo&longs;t <lb/><arrow.to.target n="marg24"></arrow.to.target><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>

<s><margin.target id="marg24"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 22.</s>

Line 997

<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 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>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>

<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 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>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 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 <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>

<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 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>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 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>

<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>

<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 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>

<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>

<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 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>

<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>

<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>

Line 1033

<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>

<s>The diligent <emph type="italics"/>Schottus<emph.end type="italics"/> tells us, That a<lb/><arrow.to.target n="marg25"></arrow.to.target><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 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>

<s>The diligent <emph type="italics"/>Schottus<emph.end type="italics"/> tells us, That a<lb/><arrow.to.target n="marg25"></arrow.to.target><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>

<s><margin.target id="marg25"></margin.target><emph type="italics"/>Schottus <lb/><gap/><emph.end type="italics"/><lb/>Part 3. <lb/>Cla&longs;&longs;. </s>

Line 1045

<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 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>

<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>

<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>

<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 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>

<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>

<s>I remember indeed that the Learned <lb/><arrow.to.target n="marg26"></arrow.to.target><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>

Line 1059

<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 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>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 pagenum="168"/>that the included &longs;ub&longs;tance might not get <lb/>away. </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>

Line 1073

<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 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>

<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>

<s><margin.target id="marg26"></margin.target><emph type="italics"/>Natural & <lb/><gap/> Hi&longs;t. <lb/><gap/> In<lb/><gap/>,<emph.end type="italics"/> Lib. 3. <lb/><gap/> 9.</s>

Line 1083

<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>

<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 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>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 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>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>

<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 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>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>

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<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="invent&utilde;">inventum</expan> &longs;it <expan abbr="aer&etilde;">aerem</expan> plus æquo <expan abbr="humi-d&utilde;">humi<lb/>dum</expan> interioribus Organi meatibus <expan abbr="maxim&utilde;">maximum</expan> <lb/>detrimentum inferre: Hinc ut aer aquo&longs;us<emph.end type="italics"/><pb 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 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="invent&utilde;">inventum</expan> &longs;it <expan abbr="aer&etilde;">aerem</expan> plus æquo <expan abbr="humi-d&utilde;">humi<lb/>dum</expan> interioribus Organi meatibus <expan abbr="maxim&utilde;">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>

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<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 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>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 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>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 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>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>

<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 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 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>

Line 1151

<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 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>

<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>

<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 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>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 pagenum="181"/>you may make it again flexible as be<lb/>fore. </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>

<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 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>

<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>

<s>SInce the writing of the twenty one and <lb/><arrow.to.target n="marg30"></arrow.to.target><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>

<s><margin.target id="marg30"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 23.</s>

<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 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>

<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>

<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 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>

<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>

<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 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 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>

<s>Moreover, having &longs;uffered the Gla&longs;&longs;es <lb/>to remain above twenty four hours in the <pb 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>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>

<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 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>

<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>

<s>AFter having thus di&longs;cover'd what ope<lb/><arrow.to.target n="marg31"></arrow.to.target><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 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>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>

<s><margin.target id="marg31"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 24.</s>

<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 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>

<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>

<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>

Line 1207

<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 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>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>

<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 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>

<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>

<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>

<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>

<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 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&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>

Line 1229

<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 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>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><pb pagenum="194"/>

<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 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 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>

<s>BEing de&longs;irous to di&longs;cover what diffe<lb/><arrow.to.target n="marg32"></arrow.to.target><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 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>BEing de&longs;irous to di&longs;cover what diffe<lb/><arrow.to.target n="marg32"></arrow.to.target><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>

<s><margin.target id="marg32"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 25.</s>

<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 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>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 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>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 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>

<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>

<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 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>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 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>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>

<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 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>

<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>

<s>IT having been ob&longs;erv'd by tho&longs;e that <lb/><arrow.to.target n="marg33"></arrow.to.target><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 pagenum="203"/>from the cover of the Receiver to which <lb/>it was fa&longs;ten'd. </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>

Line 1287

<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 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>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><pb pagenum="205"/>

<s><margin.target id="marg33"></margin.target><emph type="italics"/>Experi<lb/>ment<emph.end type="italics"/> 26.</s>

Line 1301

<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 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>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>

Line 1309

<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 pagenum="207"/>come directly in a &longs;traight Line from the <lb/>Watch unto the Ear. </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 o