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date	Fri, 07 Dec 2012 17:05:22 +0100
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-:0d8b27aa70aa
+:22d6a63640c6
+<pb>
+<C>NEW
+<I>EXPERIMENTS
+Phy$ico-Mechanicall
+Touching the Air.</I></C>
+<pb>
+<C>NEW
+EXPERIMENTS
+<I>Phy$ico-Mechanicall,</I>
+Touching</C>
+<C>The SPRING of the AIR,
+and its EFFECTS,
+(Made, for the mo$t part, in a New
+<I>PNEuMATICAL ENGINE</I>)</C>
+<C>Written by way of LETTER</C>
+<C>To the Right Honorable <I>Charles</I>
+Lord Vicount of <I>Dungarvan,</I>
+Elde$t Son to the EARL of <I>CORKE.</I></C>
+<C>By the Honorable <I>Robert Boyle</I> E$q;</C>
+<FIG>
+<C><I>OXFORD:</I>
+Printed by <I>H: Hall,</I> Printer to the Univer$ity,
+for <I>The: Robin$on.</I> 1660.</C>
+<pb>
+<FIG>
+<C>To the Reader.</C>
+<p><I>ALthough the following Trea-
+ti$e being far more prolix
+then becomes a Letter, and
+then I at fir$t intended it; I
+am very unwilling to en-
+crea$e the already exce$sive bulk of the
+Book by a Preface, yet there are $ome par-
+ticulars that I think my $elf oblig'd to take
+notice of to the Reader, as things, that will
+either concern him to know, or me to have
+known.</I>
+<p><I>In the fir$t place then: If it be demand-
+ed why I publi$h to the World a Letter, which
+by its Stile and diver$e Pa$$ages, appears
+to have been written as well For, as To a
+particular Per$on; I have chiefly the$e two
+things to an$wer: The one, That the Ex-
+periments therein related, having been ma-
+ny of them try'd in the pre$ence of Ingeni-
+ous Men; and by that means having made</I>
+<pb>
+<I>$ome noi$e among the</I> Virtuo$i (<I>in$omuch
+that $ome of them have been $ent into Fo-
+reign Countries, where they have had the
+luck not to be de$pi$'d) I could not without
+quite tyring more then one</I> Amanuen$is, <I>give
+out half as many Copies of them as were $o
+earne$tly de$ired, that I could not civilly
+refu$e them. The other, That intelligent
+Per$ons in matters of this kinde per$waded
+me, that the publication of what I had ob-
+$erv'd touching the Nature of the Air,
+would not be u$ele$s to the World; and that
+in an Age $o taken with Novelties as is ours,
+the$e n<*>w Experiments would be grateful to
+the Lovers of free and real Learning: So
+that I might at once comply with my grand
+De$ign of promoting Experimental and
+U$eful Philo$ophy, and obtain the great $a-
+tisfaction of giving $ome to ingenious Men;
+the hope of which, is, I confe$s, a tempta-
+tion that I cannot ca$ily re$i$t.</I>
+<p><I>Of my being $omewhat prolix in many
+of my Experiments, I have the$e Rea$ons
+to render, That $ome of them being altoge-
+ther new, $eem'd to need the being circum-
+$tantially related, to keep the Reader from
+di$tru$ting them: That divers Circum-
+$tances I did here and there $et down for fear
+of forgetting them, when I may hereafter</I>
+<pb>
+<I>have occa$ion to make u$e of them in my o-
+ther Writings: That in divers ca$es I
+thought it nece$$ary to deliver things cir-
+cum$tantially, that the Per$on I addre$$ed
+them to, might without mi$take, and with
+as little trouble as is po$sible, be able to re-
+peat $uch unu$ual Experiments: and that
+after I con$ented to let my Ob$ervations be
+made publick, the mo$t ordinary Rea$on of
+my prolixity was, That fore$eeing that $uch
+a trouble as I met with in making tho$e try-
+als carefully, and the great expence of time
+that they nece$$arily require, (not to mention
+the charges of making the Engine, and im-
+ploying a man to manage it) will probably
+keep mo$t men from trying again the$e Ex-
+periments; I thought I might doe the gene-
+rality of my Readers no unacceptable pe<*>ce
+of $ervice, by $o punctually relating what
+I carefully ob$erv'd, that they may look up-
+on the$e Narratives as $tanding Records in
+our new Pneumaticks, and need not reite-
+rate them$elves an Experiment to have as
+di$tinct an Idea of it, as may $uffice them
+to ground their Reflections and Speculations
+upon.</I>
+<p><I>And becau$e $ometimes 'tis the Di$cour$e
+made upon the Experiment that makes it
+appear prolix, I have commonly left a con-</I>
+<pb>
+<I>$picuous interval betwixt $uch Di$cour$es,
+and the Experiments whereunto they belong,
+or are annexed; that they who de$ire onely
+the Hi$torical part of the account we give
+of our Engine, may read the Narra-
+tives, without being put to the trouble
+of reading the Reflections too: Which I
+here take notice of, for the $ake of tho$e
+that are well ver$'d in the New Philo$ophy,
+and in the Mathematicks; that $uch
+may skip what was de$ign'd, but for $uch
+Per$ons as may be le$s acquainted even then
+I, with matters of this nature ($carce $o
+much as mention'd by any Writer in our
+Language) and not for them from whom
+I $hall be much more forward to learn, then
+to pretend to teach them. Of my being
+wont to $peak rather doubtfully, or he$itant-
+ly, then re$olvedly, concerning matters
+wherein I apprehend $ome difficulty, I have
+in another Treati$e (which may, through
+Gods A$si$tance, come abroad ere long)
+given a particular, and I hope a $atisfacto-
+ry account: Wherefore I $hall now defend
+my Practice but by the Ob$ervation of</I> Ari-
+$totle, <I>who $omewhere notes, That to $eem
+to know all things certainly, and to $peak
+po$itively of them, is a trick of bold and
+yong Fellows: Whereas tho$e that are in-</I>
+<pb>
+<I>deed intelligent and con$iderate, are wont to
+imploy more wary and diffident Expre$si-
+ons, or (as he $peaks)</I> <G><*>sife/ad<*> a)ei\ to\ <*>s,
+<*> to\ ta\xa</G>.
+<p><I>There are divers Reflections, and other
+Pa$$ages in the following Epi$tle, and even
+$ome Experiments (occa$ionally mention'd)
+which may $eem either impertinent or $u-
+perfluous, but are not $o: Being purpo$ely
+written, either to evince $ome truth oppo$'d,
+or di$prove $ome erroneous conceit main-
+tain'd, by $ome eminent New Philo$opher,
+or by $ome other Ingenious Men, who, I
+pre$um'd, would ea$ily forgive me the ha-
+ving on $uch occa$ions purpo$ely omitted
+their Names; though an inqui$itive Per$on
+will probably di$cover divers of them, by
+the mention of the Opinions di$prov'd in
+the Experiments I am excu$ing.</I>
+<p><I>Ever $ince I di$cern'd the u$efulne$s
+of $peculative Geometry to Natural Phi-
+lo$ophy, the unhappy Di$tempers of my Eyes,
+have $o far kept me from being much con-
+ver$ant in it, that I fear I $hall need the par-
+do<*> of my Mathematical Readers, for $ome
+Pa$$ages, which if I had been deeply skill'd
+in Geometry, I $hould have treated more ac-
+curately.</I>
+<pb>
+<p><I>And indeed, having, for Rea$ons el$e-
+where deduc'd, purpo$ely kept my $elf a
+$tranger to mo$t of the new</I> Hypothe$es <I>in
+Philo$ophy, I am $en$ible enough that the
+Engine I treat of has prevail'd with me to
+write of $ome $ubjects which are $ufficient-
+ly remote from tho$e I have been mo$t con-
+ver$ant in. And having been reduc'd to
+write the greate$t part of the en$uing Letter
+at a di$tance, not onely from my Library,
+but from my own Manu$cripts, I cannot
+but fear that my Di$cour$es do not onely
+want many choice things wherewith the
+Learned Writings of others might have en-
+riched or imbelli$hed them: But that partly
+for this Rea$on, and partly for that touch'd
+upon a little before, It is po$sible I may
+have mention'd $ome Notions already pub-
+li$h'd by others, without taking notice of the
+Authors, not out of any de$ign to defraud
+de$erving Men, but for want of knowing
+$uch particulars to have been already pub-
+li$h'd by them: E$pecially the Experiments
+of our Engine being them$elves $ufficient
+to hint $uch Notions as we build upon
+them.</I>
+<p><I>The order of the Experiments every
+Reader may alter, as $uits be$t with his own
+De$ign in peru$ing them; For not onely all</I>
+<pb>
+<I>tho$e betwixt whom there is an Affinity in
+Nature (by belonging to one $ubject) are not
+always plac'd one by another, but they are
+not $till $et down $o much as in the order
+wherein they were made; but mo$t common-
+ly in that ca$ual one wherein my occa$ions in-
+duc'd me to di$patch them to the Pre$s. And,
+which is wor$e, I did u$ually $end quite a-
+way the former Experiments, before the
+later were written, or perhaps $o much as
+made: Whereby I lo$t the advantage of cor-
+recting and $upplying the Imperfections of
+what I had formerly written, by the light of
+my $ub$equent Tryals and Di$coveries.</I>
+<p><I>Be$ides all this, the di$temper in my eyes
+forbidding me not onely to write my $elf $o
+much as one Experiment, but even to read
+over my $elf what I dictated to others. I can-
+not but fear, that be$ides the Authors mi$takes,
+this Edition may be blemi$h'd by many, that
+may be properly imputed to a very unskil-
+ful Writer (whom I was often times by ha$te
+reduc'd again$t my cu$tom to imploy) and
+may have e$caped the Diligence of that
+Learned Friend, that does me the favor to
+over-$ee the Pre$s; e$pecially there being
+the di$tance of two days Fourney betwixt it
+and me.</I>
+<p><I>I need not perhaps repre$ent to the equi-</I>
+<pb>
+<I>table Reader, how much the $trange Confu-
+$ions of this unhappy Nation, in the mid$t
+of which I have made and written the$e
+Experiments, are apt to di$turb that calm-
+ne$s of Minde, and undi$tractednc$s of
+Thoughts, that are wont to be requi$ite to
+Happy Speculations. But I pre$ume,
+that by all the$e things put together, he
+will readily perceive, That I have been
+$o far from following the Poets prudent
+Coun$el touching the $low Publication of
+Books de$ign'd to purcha$e credit by,</I>
+<p>&mdash;&mdash; Nonumque prematur in Annum
+<p><I>that I $uffer this Treati$e to come abroad
+into the World with a multitude of Di$ad-
+vantages.</I>
+<p><I>But if it be demanded, why then I did
+not make it f<*>ter for the Pre$s before I $ent
+it thither? my An$wer mu$t be, That not
+at fir$t imagining that this $ort of Experi-
+ments would prove any thing near $o trouble-
+$ome, either to make, or to Record, as I
+afterwards found them, I did, to engage
+the Printer to di$patch, promi$e him to $end
+him the whole Epi$tle in a very $hort time:
+So that although now and then the occa$ional
+vacations of the Pre$s, by rea$on of Fe$ti-</I>
+<pb>
+<I>vals, or the ab$ence of the Corrector, gave
+me the lei$ure to ex$paciate upon $ome $ub-
+ject; yet being oftentimes call'd upon to di$-
+patch the Papers to the Pre$s, my promi$e,
+and many unexpected Avocations, obliged
+me to a ha$te, which, though it have detract-
+ed nothing from the Faithfulne$s of the
+Hi$torical part of our Book, has (I fear)
+been di$advantageous enough to all the re$t.
+And I made the le$s $cruple to let the fol-
+lowing Papers pa$s out of my hands, with
+all their Imperfections; becau$e, as the
+publick Affairs, and my own, were then
+circum$tanc'd, I knew not when (if at all)
+I $hould be again in a condition to pro$ecute
+Experiments of this kinde; e$pecially,
+$ince (to omit my being almo$t weary of be-
+ing, as it were, confin'd to one $ort of Ex-
+periments) I am pre-ingag'd (if it plea$e
+God to vouch$afe me Life and Health) to
+imploy my fir$t lei$ure in the publication of
+$ome other Phy$iological Papers, which I
+thought 'twould make me much the $itter to
+take in hand, if I fir$t di$patch'd all that
+I had at this time to write touching our
+Engine.</I>
+<p><I>I have this further to adde, by way
+of Excu$e, That as it has been my de$ign
+in publi$hing the$e Experiments to gratifie</I>
+<pb>
+<I>Ingenious men; $o, if I have not been
+much flattered, I may hope that the vari-
+ous hints to be met with in the following
+Letter, will (at lea$t) $omewhat awaken
+mens thoughts, &amp; excite them to new $pecula-
+tions ($uch as perhaps even inqui$itive men
+would $carce el$e light upon) and I need not
+de$pair, that even the examination of $uch
+new Su$picions and Enquiries will hence al-
+$o, at lea$t Occa$ionally be facilitated: I
+$aid Occa$ionally, becau$e it being, as 'tis
+proverbially $aid,</I> Facile Inventis addere.
+<I>It $eems not irrational to expect, that our
+Engine it $elf, and divers of our Experi-
+ments, will be much promoted by the Indu-
+$try of Inventive and Mathematical Wits,
+who$e contrivances may ea$ily either correct
+or $upply, and con$equently $urpa$s many of
+tho$e we have made u$e of. And, particu-
+larly, if Men by skill and patience can ar-
+rive both to evacuate $uch Receivers as
+ours, till there be no more Air left in them,
+then there $eems to have remain'd in the
+Gla$$es made u$e of about the Magdebur-
+gick Experiment (hereafter to be mention-
+ed) and to keep out the Air for a competent
+while, the U$efulne$s and Di$coveries of our
+Engine, will not be a little advanc'd. And
+perhaps that may belong to it, which I re-</I>
+<pb>
+<I>member</I> Seneca <I>$peaks of Nature,</I> Initia-
+tos (<I>$ays be</I>) nos credimus, in Ve$tibulo
+ejus h&aelig;remus: <I>For being now in a place
+where we are not quite de$titute of moderate-
+ly skilful Artificers, we have, $ince the
+Conclu$ion of the following Letter, made
+$ome Additions to our Engine, by who$e help
+we finde (upon $ome new tryals) that we
+may be able, without much of new trouble,
+to keep the ambient Air out of the exhau-
+$ted Receiver for a whole day; and perhaps
+we $hould be able to keep it out much longer,
+if before we $hall have di$patch'd $ome ur-
+gent Affairs, and publi$h'd $ome Papers for
+which a kinde of Promi$e is thought to make
+us Debtors to the Pre$s, we could be at lei-
+$ure to pro$ecute $uch Experiments, as may
+po$sibly afford a Supplement to the follow-
+ing Treati$e, from which I $hall now no lon-
+ger detain the Reader.</I>
+<p><I>I know</I>
+<pb>
+<FIG>
+<p>Friendly Reader,
+<p><I>I Know all Per$ons
+that have a publick
+Spirit for the Ad-
+vancement of Lear-
+ning, will think much that this
+piece came not out in a Lan-
+guage of more general U$e,
+then this you $ee it now attir'd
+in; e$pecially $ince the Excel-
+lent Noble Per$on, who is the
+Author, is known to be well a-
+ble him$elf (being almo$t uni-
+ver$ally a Lingui$t) to have gi-
+ven it either the Old Latin, or</I>
+<pb>
+<I>the newer French Dre$s.</I>
+<p><I>But if it be an Honor to a
+Language to be preferr'd, and
+this Honor breeds $ometimes an
+Emulation, as anciently it did
+between the</I> Greeks <I>and</I> Ro-
+mans, <I>it cannot be thought
+unhand$ome for an Engli$h
+Nobleman to have preferr'd
+his own: And it may be a $uf-
+ficient Rea$on for the Gentry
+of Forein Parts to learn our
+Speech, or keep Interpreters,
+that they are $ure to have for
+their requital, from many of
+our Engli$h Writers (as here
+from this piece) much curiou$ly
+ingenious, and profitable Lear-
+ning.</I>
+<pb>
+<p><I>But as to this particular (give
+me leave to u$e Words from a
+Story)</I> Since the Mountain
+cannot come to <I>Mahomet,
+Mahomet</I> will go to the
+Mountain<I>: I mean thus;
+Becau$e many witty Men, Per-
+$ons of Honor and E$tate e$pe-
+cially, may be $uppo$'d to be a-
+ble to make a better account, by
+employing their Studies and
+Time on Matter then Words,
+and $o are ju$tly impeded from
+learning Languages; And be-
+cau$e (as I may judge) the no-
+ble Author is willing to oblige all
+Men, He has already provi-
+ded, that this piece $hall $hort-
+ly be done into Latine, that $o</I>
+<pb>
+<I>it may come home to divers wor-
+thy Per$ons in its Stream, who
+cannot travel to finde it out in
+its fir$t Origine.</I>
+<p><I>Having therefore leave $o
+to do, I cannot forbear to give
+the World the Adverti$ement
+of this Latine Edition, le$t
+$ome skilful Arti$t $hould take
+needle$s pains about a Work,
+which will, ere long (by Gods
+furtherance) be done to his
+Hands; For $uch unprofitable
+expences of Study have too fre-
+quently happened, and too much
+to the di$advantage of Learn-
+ing, for want of a $ufficient
+Corre$pondence and Intercour$e
+between $uch as are exerci$ed</I>
+<pb>
+<I>in the Mines of Wi$dome.</I>
+<p><I>This is all the trouble I $hall
+at pre$ent give you: Nor $hall I
+need minde thee, if you have a
+true gu$t for the Book you read,
+to have an honor and thankful
+regard to the Per$on that has
+favor'd us with the Communi-
+cation of the$e his Tryals, &amp; is
+manife$tly $o great a Patron
+and Friend to Experimental
+Learning, and all true Wi$dom;
+for $hould you fail in this, you
+might de$ervedly be depriv'd of
+$ome other Ob$ervations on the
+$ame $ubject, which the Au-
+thor, I heare, has made $ince the
+fini$hing of this Treati$e.</I>
+<p><I>I de$ire to be excu$ed that I</I>
+<pb>
+<I>not make Excu$es for the $low-
+ne$s of the Publication, hoping
+that the long expectation you
+have had of it, will enhance, and
+not dimini$h your delight in the
+enjoyment of a piece like to be,
+among$t the $tudents in accurate
+Philo$ophy, of $o generall accep-
+tance. Farewel.</I>
+<p>R: Sh.
+<FIG>
+<pb>
+<FIG>
+<C>A Summary of the chief Matters treated
+of in this Epi$tolical Di$cour$e.</C>
+<p><I>THe</I> Pro&aelig;mium, <I>wherein is $et down the
+occa$ion of this Di$cour$e,</I> 1. <I>The mo-
+tives that induc'd the Author thereunto,</I> 2 &amp;c.
+<I>The hints he received,</I> 5. <I>The things where-
+in this Engine excels any that have yet been
+made u$e of,</I> 6 &amp;c. <I>The de$cription of the
+Engine and its parts,</I> 8 &amp;c. <I>The way of pre-
+paring and u$ing it,</I> 15 &amp;c. <I>The divi$ion of
+the Experiments tryable thereby into two
+$orts, and the difficulty of excluding the
+Air.</I> 18 &amp;c.
+<p><I>The fir$t Experiment, touching the man-
+ner of pumping out the Air, and by what de-
+grees the Receiver is emptyed,</I> 20, &amp;c. <I>A di-
+gre$sion touching the Spring or Ela$tical
+power of the Air, with an attempt for a Me-
+chanical Explication thereof, nece$$ary to be
+premi$'d for the explanation of the</I> Ph&aelig;no-
+mena, <I>exhibited in this and the $ub$equent
+Experiments.</I> 22 &amp;c.
+<p><I>The $econd Experiment, touching the pre$-
+$ure of the Air again$t the $ides of the Bodies
+it invirons,</I> 37 &amp;c. <I>with a digre$sive Ex-
+plication of the pre$$ure of the Air included
+within an ambient Body.</I> 39 &amp;c.
+<pb>
+<p><I>The third Experiment, touching the
+force requi$ite to draw down the Sucker,</I> 42
+&amp;c. <I>The Opinion of an eminent Modern
+Naturali$t examin'd.</I> 44 &amp;c.
+<p><I>The fourth Experiment, touching the
+$welling of a Bladder; with the degrees by
+which it increa$es,</I> 45 &amp;c. <I>Another Opini-
+on of a Learned Author examin'd.</I> 48 &amp;c.
+<p><I>The fifth Experiment, touching the break-
+ing of a Bladder in the Receiver,</I> 49 &amp;c.
+<I>And of another by heat.</I> 52
+<p><I>The $ixth Experiment, of divers ways by
+which the ela$tical expan$ion of the Air
+was mea$ur'd.</I> 52 &amp;c
+<p><I>The $eventh Experiment, touching what
+Figure does be$t re$i$t the pre$$ure of the Air.</I> 62 &amp;c.
+<p><I>The eighth Experiment, tending to a fur-
+ther Demon$tration of the former, from the
+breaking of gla$s a Helmet inward.</I> 64 &amp;c.
+<p><I>The ninth Experiment, contains a fur-
+ther confirmation from the breaking of a
+Gla$s outward,</I> 66 &amp;c. <I>with an Experiment to
+prove, that the$e</I> Ph&aelig;nomena <I>proceed not
+from an invincible</I> Fuga vacui 69. <I>A de-
+$cription of other $mall Receivers, and their
+Conveniencies,</I> 70 &amp;c. <I>A Receipt for the
+making of a Compo$ition to Cement crackt
+Gla$$es.</I> 73
+<pb>
+<p><I>The tenth Experiment, touching the fla-
+ming of Candles inclo$ed in the Receiver.</I> 74 &amp;c.
+<p><I>The eleventh Expertment, touching the
+burning of Coals,</I> 78. <I>And the la$ting of
+the excande$cence of an included piece of I-
+ron.</I> 80.
+<p><I>The twelfth Experiment concerning the
+burning of Match.</I> 82
+<p><I>The thirteenth Experiment, concerning
+the further pro$ecution of the preceding,
+tending to prove the extinction of the Fire
+in the former Experiments, not to have
+proceeded from the pre$$ure of the Fire by the
+Fumes,</I> 84. <I>Some remarkable Circum$tan-
+ces of it,</I> 86. <I>The Experiment of Match
+try'd in a $mall Receiver.</I> 87
+<p><I>The fourteenth Experiment, touching the
+$triking Fire, and kindling of Powder with
+the Lock of a Pi$tol in the evacuated Recei-
+ver.</I> 88 &amp;c.
+<p><I>The fifteenth Experiment, touching the
+un$ucce$sfulne$s of kindling included Bo-
+dies with a burning Gla$s, and the Au-
+thors intention to pro$ecute it further.</I> 102
+<p><I>The $ixteenth Experiment, concerning the
+operation of the Load$tone.</I> 105, &amp;c.
+<pb>
+<p><I>The $eventeenth Experiment, touching the
+gradual de$cent of the Quick-$ilver in the
+Torricellian Experiment,</I> 106 &amp;c. <I>Some
+ob$ervable Circum$tances concerning it,</I>
+112 &amp;c. <I>The $ame Experiment try'd in
+one of the $mall Receivers,</I> 115. <I>How
+this Experiment may be made u$e of to know
+the $trength of the pre$$ure of the Air for
+every degree of Rarefaction,</I> 116 &amp;c. <I>The
+tryal of the $ame Experiment in a Tube not
+two foot long,</I> 118. <I>The rai$ing of the Mer-
+curial Cylinder, by the forcing of more Air
+into the Receiver,</I> 119. <I>Some Allegations
+for and again$t a</I> Vacuum <I>con$ider'd,</I> 120
+&amp;c. <I>Some Adverti$ements concerning the
+inconveniencies that may ari$e from the di-
+ver$ity of mea$ures made u$e of for the defi-
+ning the Altitute of the Mercurial Cylinder;
+and from the neglect of little parcels of Air
+apt to remain between the Mercury and the
+concave $urface of the Tube,</I> 123 &amp;c. <I>Some
+Expedients for the more exact filling the
+Tube,</I> 127. <I>The height the Author once found
+of the Mercurial Cylinder, according to En-
+gli$h mea$ure.</I> 128.
+<p><I>The eighteenth Experiment, containing
+a new Ob$ervation touching the variation
+of the height of the Mercurial Cylinder in
+the $ame Tube, with an o$$er at the rea$on</I>
+<pb>
+<I>thereof.</I> 129 &amp;c.
+<p><I>The</I> 19<SUP>th</SUP> <I>Experiment, touching the $ub-
+$iding of a Cylinder of Water,</I> 140 &amp;c. <I>The
+$ame try'd in a $mall Receiver.</I> 143
+<p><I>The</I> 20<SUP>th</SUP> <I>Experiment, touching the</I> Ela-
+ter <I>of Water, with a digre$sive Experiment
+to the $ame purpo$e</I> 144 &amp;c.
+<p><I>The</I> 21 <I>Experiment, being a pro$ecution
+of the former Enquiry, by Experimenting
+the Generation of Bubbles under Water, a
+recital of $ome notable Circum$tances, with
+$ome ob$ervable Corollary's deduc'd there-
+from.</I> 147 &amp;c.
+<p><I>The</I> 22<SUP>d</SUP> <I>Experiment, tending to a deter-
+mination of the Enquiry propo$'d in the for-
+mer Experiment, by proving the matter of
+the$e Bubbles from their permanency to be
+Air: The Experiments try'd in the great
+and $mall Receivers, evincing the $ame
+thing,</I> 155 &amp;c. <I>An Experiment wherein
+there appear'd Bubbles in Quick-$ilver,</I>
+160. <I>The Authors Inference,</I> 162. <I>A di-
+gre$sive Enquiry, whether or no Air may be
+generated anew; with $everal Hi$tories and
+Experiments, tending to the re$olving and
+clearing thereof.</I> 162 &amp;c <I>The Authors ex-
+cu$e for $o long a Digre$sion.</I> 181
+<p><I>The</I> 23<SUP>d</SUP> <I>Experiment, containing a fur-
+ther Enquiry touching Bubbles mad with</I>
+<pb>
+<I>common and di$till'd Water.</I> 182
+<p><I>The</I> 24<SUP>th</SUP> <I>Experiment, wherein the inqui-
+ry is pro$ecuted with other Liquors, as with
+Sallet Oyl, Oyl of Turpentine, a Solution of
+Tartar, Spirit of Vinegar, Red-wine, Milk,
+Hen's Eggs, Spirit of Urine, Spirit of
+Wine and Water, Spirit of Wine.</I> 187 &amp;c.
+<I>The wonderful expan$ion of the Spirit of
+Wine.</I> 194
+<p><I>The</I> 25<SUP>th</SUP> <I>Experiment, touching the ex-
+pan$ion and gravity of the Air under wa-
+ter.</I> 195 &amp;c.
+<p><I>The</I> 26<SUP>th</SUP> <I>Experiment, touching the Vi-
+brations of a</I> Pendulum. 202 &amp;c.
+<p><I>The</I> 27<SUP>th</SUP> <I>Experiment, touching the pro-
+pagation of $ound: And the Authors inten-
+tion of trying $ome other Experiments, for
+the further elucidation thereof.</I> 210 &amp;c.
+<p><I>The</I> 28 <I>Experiment, touching the $udden
+cruption of Bubbles from the water, when
+the airs pre$$ure was $peedily remov'd.</I> 214
+<p><I>The</I> 29 <I>Experiment, touching the cau$e
+of the a$cent of Fumes and Vapors, wherein
+'tis prov'd (from the $everal motions, which
+the Fumes of a $trange $moaking Liquor, of
+the Authors, were ob$erv'd to have in the Re-
+ceiver, upon the ex$uction of the Air) that
+the rea$on of their a$cent proceeds from the
+gravity of the ambient air, and not from any
+po$itive levity of their own.</I> 217 &amp;c.
+<pb>
+<p><I>The</I> 30 <I>Experiment, concerning the na-
+ture of a fluid Body, illu$trated by the exam-
+ple of $moak which in $everal circum$tances
+$eems very much to re$emble the property of a
+fluid Body,</I> 224 &amp;c. <I>A conjecture of the
+cau$e of the Suns undulation.</I> 228
+<p><I>The</I> 31 <I>Experiment, concerning the</I> Ph&aelig;-
+nomena <I>of two flat Marbles exactly plain'd
+and wrought together, and the true rea$on
+thereof,</I> 229. <I>The Authors intention for the
+further pro$ecution thereof, &amp; what hindred
+him; the rea$on why the under Marble did
+not fal from the upper (being onely conjoynd
+with Spirit of Wine) when the Receiver was
+evacuated. And a notable relation concern-
+ing the cohe$ion of flat Bodies.</I> 231 &amp;c.
+<p><I>The</I> 32 <I>Experiment, touching the forcible
+pre$$ure of the Air again$t the outward $u-
+perficies of a Valve, fa$ten'd upon the $top-
+cock of the Receiver. The Diameter of it,
+and the weight it $u$tain'd.</I> 233 &amp;c.
+<p><I>The</I> 33 <I>experiment, touching the great pre$-
+$ure of the Air again$t the under $uperficies
+of the Sucker,</I> 236 &amp;c. <I>what weight was re-
+qui$ite to depre$s it, &amp; what weight it would
+lift and carry up with it,</I> 239 &amp;c. <I>what im-
+provement &amp; u$e there may be made of this
+experiment,</I> 242. <I>A Di$cour$e touching the
+nature of Suction, proving that</I> fuga vacui
+<I>is not the adequate cau$e thereof.</I> 243 &amp;c.
+<pb>
+<p><I>The</I> 34<SUP>th</SUP> <I>Experiment, containing $everal
+attempts for the weighing of light Bodies in
+the exhau$ted Receiver.</I> 258 &amp;c.
+<p><I>The</I> 35<SUP>th</SUP> <I>Experiment, touching the cau$e
+of Filtration, and the ri$ing of Water in</I>
+Siphons, 262 &amp;c. <I>A relation of a new
+kinde of</I> Siphon, <I>of the Authors, upon
+the occa$ion of trying the Experiment
+lately ob$erv'd by $ome French-men, and fur-
+ther improv'd by him$elf; and $ome conje-
+ctures touching the cau$e of the exhibited</I>
+Ph&aelig;nomena. 267 &amp;c.
+<p><I>The</I> 36<SUP>th</SUP> <I>Experiment, touching the weigh-
+ing of a parcel of Air in the exhau$ted Ve$-
+$el; and $ome other Ob$ervations for the ex-
+plication thereof,</I> 272 &amp;c. <I>An accidental
+Experiment, tending to the further confir-
+mation of the Authors Reflections upon the
+fir$t Experiment; with a digre$sive Ob$er-
+vation, noting the $ubtil penetrancy of $ome
+Spirits, to exceed by far that of the Air,</I> 275
+&amp;c. <I>And $ome other Experiments to $hew the
+difficulty of the ingre$s of the Air into the
+pores or holes of $ome bodies into which Wa-
+ter will readily in$inuate it $elf,</I> 279 &amp;c. <I>with
+a conjecture at the cau$e thereof,</I> 282. <I>The
+Author returns to the pro$ecution if the in-
+quiry after the gravity of the Air: But fir$t,
+(upon the occa$ion of the tenacity of a thin</I>
+<pb>
+<I>Bubble of Gla$s) $ets down his thoughts con-
+cerning the $trange exuperancy of $trength
+in Air, agitated by heat, above what the
+$ame has unagitated,</I> 283 &amp;c. <I>And then pro-
+ceeds to the examination of the weight of the
+Air by an</I> &AElig;olipile, <I>and compares the re$ult
+thereof, with that of</I> Mer$ennus, 286. <I>The
+Opinions and Experiments of divers Au-
+thors, and $ome of his own, touching the
+proportion of weight betwixt Water and Air,
+are compar'd and examin'd by the Author,</I>
+288. <I>The re$ult thereof,</I> 290. Mer$ennus
+<I>his ob$ervation reconcil'd, with that of the
+Author; and the proportion between the gra-
+vity of Water and Air about</I> London, 291
+&amp;c. <I>After the recital of the Opinions of $e-
+veral Writers, touching the proportion of
+gravity between Water and Quick-$ilver,
+the Author $ets down his own tryals, made
+$everal ways, together with his conclu$ion
+therefrom,</I> 293 &amp;c. <I>The u$e he makes of this
+inquiry for the ghe$sing at the height of the
+Atmo$phere,</I> 297. <I>What other Experiments
+are requi$ite to the determination thereof.</I>
+299 &amp;c.
+<p><I>The</I> 37<SUP>th</SUP> E<I>xperiment, touching the $trange
+and odde</I> Ph&aelig;nomenon, <I>of the $udden fla$h-
+es of light in the cavity of the Receiver; the
+$everal circum$tances and difficulties of it,</I>
+<pb>
+<I>with $ome attempts towards the rendering at rea$on
+thereof,</I> 301, &amp;c. <I>The Difficulty of $o doing fnr-
+ther $hewn from the con$ideration of the various
+changes of Air which doe not immediatly fall un-
+der our $en$es,</I> 315. <I>this la$t propo$ition prou'd
+by $everall ob$ervations.</I> 316.
+<p><I>The</I> 38. <I>Experiment, touching the freezing of
+water,</I> 319. &amp;c. <I>Aproblem, (concerning the great
+force wherewith a freezing Liquor extends its $<*>lfe,)
+propo$'d upon the Con$ideration of divers admirable
+effects wrought thereby.</I> 320 &amp;c.
+<p><I>The</I> 39. <I>Experiment, containing an inqui$ition
+after the temperature of the $ub$tance that remain'd
+in the cavity of the Receiver, after the Air was well
+exhau$ted. The relation of a</I> Ph&aelig;nomenon, <I>$eeming
+to proceed from the $welling of the Gla$s. With an
+adverti$ement concerning the pliablene$s of Gla$s in
+$mall peices.</I> 322. &amp;c.
+<p><I>The</I> 40. <I>Experiment, touching the difficulty that
+occur'd in making tryall whether rarified Air
+were able to $u$taine flying in$ects.</I> 326. &amp;c
+<p><I>The</I> 41. <I>Experiment, Exhibiting $everall try-
+alls touching the re$piration of divers $orts of ani-
+malls included in the Receiver,</I> 328, &amp;c. <I>With a
+digre$$ion containing $ome doubts touching re$pira-
+tion wherein are delivered $everall Experiments re-
+lating thereunto.</I> 335 &amp;c.
+<p><I>The</I> 42. <I>Experiment, touching the differing o-
+peration of corro$ive Liquors in the emptied Receiver
+and in the open Air.</I> 384
+<p><I>The</I> 43. <I>Experiment, touching the $pontaneous E-
+bullition of warm Liquors in the exhau$ted Receiver.</I> 388
+<p><I>The Conclu$ion.</I> 394
+<pb>
+<FIG>
+<pb>
+<FIG>
+<pb>
+<FIG>
+<pb>
+<FIG>
+<pb n=1>
+<FIG>
+<C>TO THE
+LORD
+OF
+<I>DUNGARVAN,</I>
+My Honoured and Dear
+NEPHEW.</C>
+<p><I>My Dear Lord,</I>
+<p>REceiving in your la$t from
+<I>Paris,</I> a de$ire that I would
+adde $ome more Experi-
+ments to tho$e I formerly
+$ent You over: I could not
+be $o much your Servant as I am, without
+looking upon that De$ire as a Com-
+mand; and con$equently, without think-
+ing my $elf obliged to con$ider by what
+$ort of Experiments it might the mo$t ac-
+ceptably be obey'd. And at the $ame
+<pb n=2>
+time, perceiving by Letters from $ome
+other Ingenious Per$ons at <I>Paris,</I> that $e-
+veral of the <I>Virtuo$i</I> there, were very
+intent upon the examination of the Inte-
+re$t of the Ayr, in hindring the de$cent
+of the Quick-$ilver, in the famous Expe-
+riment touching a <I>Vacuum:</I> I thought I
+could not comply with your De$ires in a
+more fit and $ea$onable manner, then by
+pro$ecuting and endeavoring to promote
+that noble Experiment of <I>Torricell<*>s:</I>
+and by pre$enting your Lord$hip an ac-
+count of my attempts to illu$trate a $ub-
+ject, about which, it's being $o much di$-
+cour$'d of where you are, together with
+your inbred Curio$ity, and love of Ex-
+perimental Learning, made me $uppo$e
+you $ufficiently inqui$itive.
+<p>And though I pretend not to acquaint
+you, on this occa$ion, with any $tore of
+new Di$coveries yet po$$ibly I $hall be $o
+happy, as to a$$i$t you to <I>know</I> $omethings
+which you did formerly but <I>$uppo$e;</I> and
+$hall pre$ent you, if not with new Theo-
+ries, at lea$t with new <I>Proofs</I> of $uch as
+are not yet become unque$tionable. And
+if what I $hall deliver, have the good for-
+tune to encourage and a$$i$t you to pro$e-
+cute the Hints it will afford, I $hall ac-
+<pb n=3>
+count my $elf, in paying of a duty to
+you, to have done a piece of Service to
+the Commonwealth of Learning. Since
+it may highly conduce to the advance-
+ment of that Experimental Philo$ophy,
+the effectual pur$uit of which, requires
+as well a Pur$e as a <*>in, to endeere it
+to <I>hopeful</I> Per$ons of your Quality: who
+may accompli$h many things which o-
+thers can but <I>wi$h</I> or, at mo$t, but <I>de$ign,</I>
+by being able to imploy the Pre$ents of
+Fortune in the $earch of the My$teries of
+Nature.
+<p>And I am not faintly induc'd to make
+choice of this Subject, rather then any
+of the expected Chymical ones, to enter-
+tain your Lord$hip upon, by the$e two
+Con$iderations: The one, That the Ayr
+being $o nece$$ary to humane Life, that
+not onely the generality of Men, but
+mo$t other Creatures that breath, can-
+not live many <I>minutes</I> without it; any
+con$iderable di$covery of its Nature,
+$eems likely to prove of moment to
+Man-kinde. And the other is, That the
+Ambient Ayr, being that whereto both
+our own Bodies, and mo$t of the others
+we deal with here below, are almo$t per-
+petually contiguous; not onely its alte-
+<pb n=4>
+rations have a notable and manife$t $hare
+in tho$e obvious effects, that men have
+already been invited to a$cribe thereunto
+$uch as are the various di$tempers inci-
+dent to humane Bodies, e$pecially if cra-
+zy, in the Spring, the Autumn, and al$o
+on mo$t of the great and $udden changes
+of Weather) but likewi$e, that the fur-
+ther di$covery of the nature of the Ayr,
+will probably di$cover to us, that it con-
+curs more or le$s to the exhibiting of ma-
+ny <I>Ph&aelig;nomena,</I> in which it hath hither-
+to $carce been $u$pected to have any inte-
+re$t. So that a True Account of any
+Experiment that is New concerning a
+thing, wherewith we have $uch con$tant
+and nece$$ary intercour$e, may not one-
+ly prove of $ome advantage to humane
+Life, but gratifie Philo$ophers, by pro-
+moting their Speculations on a Subject
+which hath $o much opportunity to $olli-
+cite their Curio$ity.
+<p>And I $hould immediately proceed to
+the mention of my Experiments, but that
+I like too well that worthy $aying of the
+Naturali$t <I>Pliny, Benignum e$t</I>
+<MARG><I>In <*>.
+lib.</I> 1.</MARG>
+<I>&amp; plenum ingenui pudor is, fateri
+per quos profeceris,</I> not to con-
+form to it, by acquainting your Lord-
+<pb n=5>
+$hip, in the fir$t place, with the Hint I
+had of the Engine I am to entertain you
+of. You may be plea$'d to remember,
+that a while before our $eparation in <I>Eng-
+land,</I> I told you of a Book that I had
+heard of, but not peru$'d, publi$h'd by
+the indu$trious Je$uit <I>Schottus,</I> wherein
+'twas $aid, He related how that ingenious
+Gentleman <I>Otto Gericke,</I> Con$ul of <I>Mag-
+deburg,</I> had lately practiced in <I>Germany</I> a
+way of emptying Gla$s Ve$$els, by $uck-
+ing out the Ayr at the mouth of the Ve$-
+$el, plung'd under water: And you may
+al$o perhaps remember, that I expre$$'d
+my $elf much delighted with this Expe-
+riment, $ince thereby the great force of
+the external Air (either ru$hing in at the
+open'd Orifice of the empty'd Ve$$el, or
+violently forcing up the Water into it)
+was rendred more obvious and con$picu-
+ous, than in any Experiment that I had
+formerly $een. And though it may appear
+by $ome of tho$e Writings I $ometimes
+fhew'd your Lord$hip, that I had been $ol-
+licitous to try things upon the $ame
+ground; yet in regard this Gentleman
+was before-hand with me in producing
+$uch con$iderable effects, by means of the
+ex$uction of Air, I think my $elf oblig'd
+<pb n=6>
+to acknowledge the A$$i$tance, and En-
+couragement the Report of his perfor-
+mances hath afforded me.
+<p>But as few inventions happen to be at
+fir$t $o compleat, as not to be either ble-
+mi$hd with $ome deficiencies needful to be
+remedy'd, or otherwi$e capable of im-
+provement: $o when the Engine we
+have been $peaking of, comes to be more
+attentively con$ider'd, there will appear
+two very con$iderable things to be de-
+$ir'd in it. For fir$t, the <I>Wind-Pump</I> (as
+$ome body not improperly calls it) is $o
+contriv'd, that to evacuate the Ve$$el
+there is requir'd the continual labor of
+two $trong men for divers hours. And
+next (which is an imperfection of much
+greater moment) the Receiver, or Gla$s
+to be empty'd, con$i$ting of one entire
+and uninterrupted Globe and Neck of
+Gla$s; the whole Engine is $o made, that
+things cannot be convey'd into it, where-
+on to try Experiments: So that there
+$eems but little (if any thing) more to be
+expected from it, then tho$e very few
+<I>Ph&aelig;nomena</I> that have been already ob-
+$erv'd by the Author, and Recorded by
+<I>Schottus.</I> Wherefore to remedy the$e
+Inconveniences, I put both Mr. <I>G.</I>
+<pb n=7>
+and <I>R. Hook</I> (who hath al$o the Honor to
+be known to your Lord$hip, and was with
+me when I had the$e things under con$i-
+deration) to contrive $ome Air Pump,
+that might not, like the other, need to
+be kept under water (which on divers oc-
+ca$ions is inconvenient) &amp; might be more
+ea$ily manag'd: And after an un$ucce$sful
+try all or two of ways propo$'d by o-
+thers, the la$t nam'd Per$on fitted me
+with a Pump, anon to be de$crib'd. And
+thus the fir$t Imperfection of the <I>German</I>
+Engine, was in good mea$ure, though
+not perfectly, remedy'd: And to $upply
+the $econd de$ect, it was con$idered that
+it would not perhaps prove impo$$ible to
+leave in the Gla$s to be empty'd, a hole
+large enough to put in a Mans Arm
+cloath'd; and con$equently other Bodies,
+not bigger then it, or longer then the in-
+$ide of the Ve$$el. And this De$ign
+$eem'd the more hopefull, becau$e I re-
+membred, that having $everal years be-
+fore often made the Experiment <I>De Va-
+cuo</I> with my own hands; I had, to exa-
+mine $ome conjectures that occurr'd to
+me about it, cau$ed Gla$$es to be made
+with a hole at that end, which u$es to be
+$eal'd up, and had neverthele$s been able
+<pb n=8>
+as occa$ion requir'd, to make u$e of $uch
+Tubes, as if no $uch holes had been left
+in them; by devi$ing $topples for them,
+made of the common Plai$ter call'd <I>Dia-
+chylon:</I> which I rightly enough ghe$$'d,
+would, by rea$on of the exqui$ite com-
+mixtion of its $mall parts, and clo$ene$s
+of its texture, deny all acce$s to the ex-
+ternal Air. Wherefore, $uppo$ing that
+by the help of $uch Plai$ters, carefully
+laid upon the commi$$ures of the $topple
+and hole to be made in the Receiver, the
+external Air might be hindred from in$i-
+nuating it $elf between them into the Ve$-
+$el, we cau$'d $everal $uch Gla$$es, as
+you will finde de$crib'd a little lower, to
+be blown at the Gla$s-hou$e; and though
+we could not get the Work-men to blow
+any of them $o large, or of $o conveni-
+ent a $hape as we would fain have had; yet
+finding one to be tolerably fit, and le$s
+unfit then any of the re$t, we were con-
+tent to make u$e of it in that En-
+gine: Of which, I $uppo$e, you by this
+time expect the De$cription, in order to
+the Recital of the <I>Ph&aelig;nomena</I> exhibited
+by it.
+<p>To give your Lord$hip then, in the
+fir$t place, $ome account of the Engine it
+<pb n=9>
+$elf: It con$i$ts of two principal parts; a
+gla$s Ve$$el, and a Pump to draw the Air
+out of it.
+<p>The former of the$e (which we, with
+the Gla$s men, $hall often call a Receiver,
+for its affinity to the large Ve$$els of that
+name, u$ed by Chymi$ts) con$i$ts of a
+Gla$s with a wide hole at the top, of a
+cover to that hole, and of a $top-cock
+fa$tned to the end of the neck, at the
+bottom.
+<p>The $hape of the Gla$s, you will find
+expre$$'d in the fir$t Figure of the annex-
+ed Scheme. And for the $ize of it, it
+contain'd about 30 Wine Quarts, each of
+them containing near two pound (of 16
+Ounces to the pound) of water: We
+$hould have been better plea$'d with a
+more capacious Ve$$el, but the Gla$s-men
+profe$$ed them$elves unable to blow a
+larger, of $uch a thickne$s and $hape as
+was requi$ite to our purpo$e.
+<p>At the very top of the Ve$$el, (A) you
+may ob$erve a round hole, who$e Dia-
+meter (B C) is of about four inches; and
+whereof, the Orifice is incircled with a
+lip of Gla$s, almo$t an inch high: For
+the making of which lip, it was requi$ite
+(to mention that upon the by, in ca$e
+<pb n=10>
+your Lord$hip $hould have $uch another
+Engine made for you) to have a hollow
+and tapering Pipe of Gla$s drawn out,
+whereof the Orifice above mentioned
+was the Ba$is, and then to have the cone
+cut off with a hot Iron, within about an
+Inch of the Points (B C.)
+<p>The u$e of the lip, is to $u$tain the
+cover delineated in the $econd Figure;
+where (D E) points out a bra$s Ring, $o
+ca$t, as that it doth within and without
+cover the lip (B C) of the fir$t Figure,
+and is cemented on upon it with a $trong
+and clo$e Cement. To the inward taper-
+ing Orifice of this Ring (which is about
+three Inches over) are exqui$itely ground
+the $ides of the Bra$s $topple (F G;) $o
+that the concave $uperficies of the one,
+and the convex of the other, may touch
+one another in $o many places, as may
+leave as little acce$s, as po$$ible, to the ex-
+ternal Air: And in the mid$t of this cover
+is left a hole (H I) of about half an inch
+over, invironed al$o with a ring or $ocket
+of the $ame mettal, and fitted likewi$e
+with a bra$s $topple (K) made in the form
+of the Key of a $top-cock, and exactly
+ground into the hole (H I) it is to fill; $o
+as that though it be turn'd round in the
+<pb n=11>
+cavity it po$$e$$es, it will not let in the
+Air, and yet may be put in or taken out
+at plea$ure, for u$es to be hereafter men-
+tioned. In order to $ome of which, it is
+perforated with a little hole, (8) traver$ing
+the whole thickne$s of it at the lower
+end; through which, and a little bra$s
+Ring (L) fa$tned to one $ide, (no matter
+which) of the bottom of the $topple
+(FG) a $tring (8, 9, 10) might pa$s, to
+be imploy'd to move $ome things in the
+capacity of the empty'd Ve$$el; without
+any where un$topping it.
+<p>The la$t thing belonging to our Recei-
+ver, is the $top-cock de$igned in the fir$t
+Figure by (N.) for the better fa$tening
+of which to the neck, and exacter exclu$i-
+on of the Air, there was $oder'd on to
+the $hank of the Cock (X) a Plate of
+Tin, (MTUW) long enough to cover
+the neck of the Receiver. But becau$e
+the cementing of this was a matter of
+$ome difficulty, it will not be ami$s to
+mention here the manner of it, which
+was, That the cavity of the tin Plate was
+fill'd with a melted Cement, made of
+Pitch, Ro$in, and Wood-a$hes, well in-
+corporated; and to hinder this liquid
+Mixture from getting into the Orifice (Z)
+<pb n=12>
+of the $hank, (X) that hole was $topt
+with a Cork, to which was fa$tned a $tring,
+whereby it might be pull'd out of the up-
+per Orifice of the Receiver; and then,
+the gla$s neck of the Receiver being well
+warm'd, was thru$t into this Cement, and
+over the $hank whereby it was effected,
+that all the $pace betwixt the tin Plate and
+the Receiver, and betwixt the internal
+$uperficies of the Receiver, and the
+$hanck of the Cock, was filld with the
+Cement; and $o we have di$pach'd the
+fir$t and upper part of the Engine.
+<p>The undermo$t remaining part con$i$ts
+of a Frame, and of a $ucking Pump, or
+as we formerly call'd it, an Air Pump, $up-
+ported by it: The Frame is of Wood,
+$mall, but very $trong, con$i$ting of three
+legs, (111) $o plac'd, that one $ide of
+it may $tand perpendicular, that the free
+motion of the hand may not be hindered.
+In the mid$t of which frame, is tran$ver$ly
+nail'd a board, (222) which may not im-
+properly be call'd a Midriff, upon which
+re$ts, and to which is $trongly fa$tned, the
+main part of the Pump it $elf, which is
+the onely thing remaining to be de$cri-
+bed.
+<p>The Pump con$i$ts of four parts, a
+<pb n=13>
+hollow Cylindre, a Sucker, a handle to
+move that Sucker, and a Valve.
+<p>The Cylindre was (by a pattern) ca$t
+of bra$s; it is in length about 14 inches,
+thick enough to be very $trong, notwith-
+$tanding the Cylindrical cavity left with-
+in it; this cavity is about three inches
+Diameter, and makes as exact a Cylin-
+dre as the Artificer was able to bore.
+This hollow Cylindre is fitted with a $uck-
+er, (4455) con$i$ting of two parts, the
+one (44) $omewhat le$s in Diameter then
+the cavity of the Cylindre, upon which
+is nail'd a good thick piece of tan'd $hoe
+Leather, which will go $o clo$e to the
+Cylindre, that it will need to be very
+forcibly knock'd and ram'd in, if at any
+time it be taken out, which is therefore
+done, that it may the more exactly hin-
+der the Air from in$inuating it $elf be-
+twixt it and the $ides of the Cylindre
+whereon it is to move.
+<p>To the mid$t of this former part of the
+Sucker is $trongly fa$tned the other,
+namely a thick and narrow plate of Iron,
+(55) $omewhat longer then the Cylindre,
+one of who$e edges is $mooth, but at the
+other edge it is indented (as I may $o
+$peak) with a row of teeth delineated in
+<pb n=14>
+the Scheme, into who$e intervals are to
+be fitted, the teeth of a $mall Iron nut;
+(<*>) (as Trade$-men call it) which is fa$t-
+ned by two $taples (22) to the under $ide
+of the formerly mention'd tran$ver$e
+board (222) on which the Cylindre re$ts,
+and is turn'd to and fro by the third piece
+of this Pump, namely, the handle or
+<I>manubrium,</I> (7) of which the Figure gives
+a $ufficient de$cription.
+<p>The fourth and la$t part of this Cylin-
+dre, is the Valve, (R) con$i$ting of a
+hole bored through at the top of the Cy-
+lindre, a little tapering towards the cavi-
+ty; into which hole is ground a tapering
+Peg of bra$s, to be thru$t in, and taken
+out at plea$ure.
+<p>The Engine being thus de$crib'd, it
+will be requi$ite to adde, that $omething
+is wont to be done before it be $et on
+work, for the more ea$ie moving of the
+Sucker, and for the better exclu$ion of
+the outward Air: which when the Ve$$el
+begins to be exhau$ted, is much more dif-
+ficult to be kept out then one would ea$i-
+ly imagine.
+<p>There mu$t then be fir$t powr'd in at
+the top of the Receiver a little $allad oyl,
+partly to fill up any $mall intervalls that
+<pb n=15>
+may happen to be betwixt the contigu-
+ous $urfaces of the internal parts of the
+Stop-cock: And partly that it may be
+the more ea$ie to turn the Key (S) back-
+wards and forwards. Pretty $tore of oyl
+mu$t al$o be pour'd into the Cylindre,
+both that the Sucker may $lip up and
+down in it the more $moothly and freely,
+and that the Air might be the better
+hindred from getting in between them:
+And for the like rea$ons, a little oyl is to
+be u$ed al$o about the Valve. Upon
+which occa$ion, it would not be omitted
+(for it is $trange) that oftentimes, when
+neither the pouring in of water, nor even
+of oyl alone, prov'd capable to make the
+Sucker move ea$ily enough in the Cylin-
+der; a mixture of both tho$e Liquors
+would readily ($ometimes even to admi-
+ration) perform the de$ired effect. And
+la$tly, the bra$s cover of the Receiver,
+being put into the bra$s ring formerly de-
+$crib'd, that no Air may get between
+them, it will be very requi$ite to plai$ter
+over very carefully the upper edges of
+both, with the plai$ter formerly mention-
+ed, or $ome other as clo$e, which is to be
+$pread upon the edges with a hot Iron;
+that being melted, it may run into and
+<pb n=16>
+fill up all the crannies, or other little ca-
+vities, at which the Air might otherwi$e
+get entrance.
+<p>All things being thus fitted, and the
+lower $hank (O) of the $top-cock being
+put into the upper Orifice of the Cylin-
+der (&amp;), into which it was exactly ground;
+the Experimenter is fir$t, by turning the
+handle, to force the Sucker to the top of
+the Cylinder, that there may be no Air
+left in the upper part of it: Then $hut-
+ting the Valve with the Plug, and turning
+the other way, he is to draw down the
+Sucker to the bottom of the Cylinder;
+by which motion of the Sucker, the Air
+that was formerly in the Cylinder being
+thru$t out, and none being permitted to
+$ucceed in its room, 'tis manife$t that the
+cavity of the Cylinder mu$t be empty,
+in reference to the Air: So that if there-
+upon the Key of the Stop-cock be $o
+turn'd, as that through the perforation of
+it, a free pa$$age be opened betwixt the
+Cylinder and the Receiver, part of the
+Air formerly contain'd in the Receiver,
+will nimbly de$cend into the Cylinder.
+And this Air, being by the turning back
+of the Key hinder'd from the returning
+into the Receiver, may, by the opening
+<pb n=17>
+of the Valve, and forcing up of the Suck-
+er to the top of the Cylinder again, be
+driven out into the open Air. And thus
+by the repetition of the motion of the
+Sucker upward and downward, and by op-
+portunely turning the Key, and $topping
+the Valve, as occa$ion requires, more or
+le$s Air may be $uck'd out of the Recei-
+ver, according to the exigency of the Ex-
+periment, and the intention of him that
+makes it.
+<p>Your Lord$hip will, perhaps, think that
+I have been unnece$$arily prolix in this
+fir$t part of my Di$cour$e: But if you
+had $een how many unexpected difficul-
+ties we found to keep out the externall
+Air, even for a little while, when $ome
+con$iderable part of the internal had been
+$uckt out; You would peradventure al-
+low, that I might have $et down more
+circum$tances then I have, without $et-
+ting down any, who$e knowledge, he that
+$hall try the Experiment may not have
+need of. Which is $o true, that, before we
+proceed any further, I cannot think it un-
+$ea$onable to adverti$e Your Lord$hip,
+that there are two chief $orts of Experi-
+ments, which we de$ign'd in our Engine
+to make tryal of: The one, $uch as may
+<pb n=18>
+be quickly di$patcht, and therefore may
+be try'd in our Engine, though it leak a
+little; becau$e the Air may be fa$ter drawn
+out, by nimbly plying the Pump, then
+it can get in at undi$cern'd leaks; I $ay at
+undi$cern'd leaks, becau$e $uch as are big
+enough to be di$cover'd can $carce be un-
+ea$ie to be $topt. The other $ort of Ex-
+periments con$i$ts of tho$e that require
+not onely that the internal Air be drawn
+out of the Receiver, but that it be like-
+wi$e for a long time kept out of it. Such
+are the pre$ervation of Animal and o-
+ther Bodies therein, the germination and
+growth of Vegetables, and other tryals
+of $everal $orts, which it is apparent can-
+not be well made unle$s the external Air
+can, for a competent while, be excluded:
+Since even at a very $mall leak there may
+enough get in, to make the <I>Vacuum</I> $oon
+loo$e that name; by which I here declare
+once for all, that I under$tand not a $pace
+wherein there is no body at all, but $uch
+as is either altogether, or almo$t totally
+void of Air.
+<p>Now this di$tinction of Experiments
+I thought fit to premi$e to the en$uing
+Narratives, becau$e upon tryal, we found
+it $o exceeding (and $carce imaginable) dif-
+<pb n=19>
+ficult a matter, to keep out the Air from
+getting at all in at any imperceptible hole
+or flaw what$oever, in a Ve$$el immedi-
+ately $urrounded with the compre$$ed At-
+mo$phere, that in $pight of all our care
+and diligence, we never were able totally
+to exhau$t the Receiver, or keep it when
+it was almo$t empty, any con$iderable
+time, from leaking more or le$s: although
+(as we have lately intimated) by unwearyed
+quickne$s in plying the Pump, the inter-
+nall Air can be much fa$ter drawn out
+then the external can get in, till the Re-
+ceiver come to be almo$t quite empty.
+And that's enough to enable men to di$-
+cover hitherto unob$erved <I>Ph&aelig;nomena</I> of
+Nature.
+<p>The Experiments therefore of the fir$t
+$ort, will, I fear, prove the onely ones
+wherewith my Avocations will allow me
+to entertain Your Lord$hip in this Letter.
+For till your further Commands $hall en-
+gage me to undertake, by Gods permi$-
+$ion, $uch an Employment, and more lea-
+$ure $hall better fit me for it, I know not
+whether I $hall be in a condition to try
+what may be done, to enable me to give
+you $ome account of the other $ort of
+Experiments al$o.
+<pb n=20>
+<p>TO proceed now to the <I>Ph&aelig;nomena,</I>
+<MARG><I>Experi-
+ment</I> 1.</MARG>
+exhibited to us by the Engine above
+de$cribed; I hold it not unfit to begin
+with what does con$tantly and regularly
+offer it $elf to our ob$ervation, as depend-
+ing upon the Fabrick of the Engine it $elf,
+and not upon the nature of this or that
+particular Experiment which 'tis employ-
+ed to try.
+<p>Fir$t, Then upon the drawing down
+of the Sucker, (the Valve being $hut) the
+Cylindrical $pace, de$erted by the Sucker,
+is left de void of Air; and therefore, up-
+on the turning of the Key, the Air con-
+tained in the Receiver ru$hes into the em-
+ptyed Cylinder, till the Air in both tho$e
+Ve$$els be brought to about an equal
+mea$ure of dilatation. And therefore,
+upon $hutting the Receiver by returning
+the Key, if you open the Valve, and force
+up the Sucker again, you will finde, that
+after this fir$t ex$uction you will drive
+out almo$t a whole Cylinder full of Air:
+But at the following ex$uctions, you will
+draw le$s and le$s of Air out of the Recei-
+ver into the Cylinder, becau$e that there
+will $till remain le$s and le$s Air in the
+<pb n=21>
+Receiver it $elf; and con$equently, the
+Particles of the remaining Air, having
+more room to extend them$elves in, will
+le$s pre$s out one another. This you will
+ea$ily perceive, by finding, that you $till
+force le$s and le$s Air out of the Cylin-
+der; $o that when the Receiver is almo$t
+exhau$ted, you may force up the Sucker
+almo$t to the top of the Cylinder, be-
+fore you will need to un$top the Valve to
+let out any Air: And if at $uch time, the
+Valve being $hut, you let go the handle of
+the Pump, you will finde the Sucker for-
+cibly carryed up to the top of the Cylin-
+der, by the protru$ion of the external Air;
+which, being much le$s rarified then that
+within the Cylinder, mu$t have a more
+forcible pre$$ure upon the Sucker, then
+the internal is able to re$i$t: And by this
+means you may know how far you have
+emptyed the Receiver. And to this we
+may adde, on this occa$ion, that con$tant-
+ly upon the turning of the Key to let out
+the Air from the Receiver, into the em-
+ptied Cylinder, there is immediately pro-
+duced a con$iderably brisk noi$e, e$peci-
+ally whil'$t there is any plenty of Air in
+the Receiver.
+<pb n=22>
+<p>For the more ea$ie under$tanding of the
+Experiments tryable by our Engine, I
+thought it not $uperfluous, nor un$ea$on-
+able in the recital of this fir$t of them, to
+in$inuate that notion by which it $eems
+likely that mo$t, if not all, of them will
+prove explicable. Your Lord$hip will
+ea$ily $uppo$e, that the Notion I $peak
+of is, That there is a Spring, or Ela$ti-
+cal power in the Air we live in. By which
+<G>e)latg\r</G> or Spring of the Air, that which
+I mean is this: That our Air either con-
+$i$ts of, or at lea$t abounds with, parts of
+$uch a nature, that in ca$e they be bent or
+compre$$'d by the weight of the incum-
+bent part of the Atmo$phere, or by any o-
+ther Body, they do endeavor, as much as
+in them lies, to free them$elves from that
+pre$$ure, by bearing again$t the contigu-
+ous Bodies that keep them bent; and,
+a$$oon as tho$e Bodies are remov'd or
+reduced to give them way, by pre$ently
+unbending and $tretching out them$elves,
+either quite, or $o far forth as the con-
+tiguous Bodies that re$i$t them will per-
+mit, and thereby expanding the whole
+parcel of Air, the$e ela$tical Bodies com-
+po$e.
+<pb n=23>
+<p>This Notion may perhaps be $ome-
+what further explain'd, by conceiving the
+Air near the Earth to be $uch a heap of
+little Bodies, lying one upon another, as
+may be re$embled to a Fleece of Wooll.
+For this (to omit other likene$$es betwixt
+them) con$i$ts of many $lender and flexi-
+ble Hairs; each of which, may indeed,
+like a little Spring, be ea$ily bent or roul-
+ed up; but will al$o, like a Spring, be
+$till endeavouring to $tretch it $elf out
+again. For though both the$e Haires,
+and the Aerial Corpu$cles to which we
+liken them, do ea$ily yield to externall
+pre$$ures; yet each of them (by vertue of
+its $tructure) is endow'd with a Power or
+Principle of $elf-Dilatation; by vertue
+whereof, though the hairs may by a Mans
+hand be bent and crouded clo$er together,
+and into a narrower room then $uits be$t
+with the nature of the Body: Yet whil'$t
+the compre$$ion la$ts, there is in the fleece
+they compo$e an endeavour outwards,
+whereby it continually thru$ts again$t the
+hand that oppo$es its Expan$ion. And
+upon the removall of the external pre$-
+$ure, by opening the hand more or le$s, the
+compre$$ed Wooll does, as it were, $pon-
+taneou$ly expand or di$play it $elf towards
+<pb n=24>
+the recovery of its former more loo$e and
+free condition, till the Fleece have ei-
+ther regain'd its former Dimen$ions, or
+at lea$t, approach'd them as near as the
+compre$$ing hand (perchance not quite
+open'd) will permit. This Power of
+$elf-Dilatation, is $omewhat more con$pi-
+cuous in a dry Spunge compre$$'d, then
+in a Fleece of Wooll. But yet we ra-
+ther cho$e to imploy the latter, on this
+occa$ion, becau$e it is not like a Spunge,
+an entire Body, but a number of $len-
+der and flexible Bodies, loo$ely com-
+plicated, as the Air it $elf $eems to
+be.
+<p>There is yet another way to explicate
+the Spring of the Air, namely, by $uppo-
+$ing with that mo$t ingenious Gentleman,
+Mon$ieur <I>Des Cartes,</I> That the Air is no-
+thing but a Congeries or heap of $mall
+and (for the mo$t part) of flexible Parti-
+cles; of $everal $izes, and of all kinde of Fi-
+gures which are rai$'d by heat (e$pecially
+that of the Sun) into that fluid and
+$ubtle Etheriall Body that $urrounds
+the Earth; and by the re$tle$$e agi-
+tation of that Cele$tial Matter where-
+in tho$e Particles $wim, are $o whirl'd
+<pb n=25>
+round, that each Corpu$cle endeavours
+to beat off all others from coming within
+the little Sphear requi$ite to its motion
+about its own Center; and (in ca$e any,
+by intruding into that Sphear $hall op-
+po$e its free Rotation) to expell or drive
+it away: So that according to this Do-
+ctrine, it imports very little, whether the
+particles of the Air have the $tructure re-
+qui$ite to Springs, or be of any other
+form (how irregular $oever) $ince their
+Ela$tical power is not made to depend
+upon their $hape or $tructure, but upon
+the vehement agitation, and (as it were)
+brandi$hing motion, which they receive
+from the fluid <I>Ether</I> that $wiftly flows
+between them, and whirling about each
+of them (independently from the re$t)
+not onely keeps tho$e $lender A&euml;rial
+Bodies $eparated and $tretcht out (at lea$t,
+as far as the Neighbouring ones will per-
+mit) which otherwi$e, by rea$on of
+their flexiblene$s and weight, would
+flag or curl; but al$o makes them hit
+again$t, and knock away each other, and
+con$equently require more room, then
+that which if they were compre$$'d, they
+would take up.
+<pb n=26>
+<p>By the$e two differing ways, my Lord,
+may the Spring of the Air be explicated.
+But though the former of them be that,
+which by rea$on of its $eeming $omewhat
+more ea$ie, I $hall for the mo$t part make
+u$e of in the following Di$cour$e: yet
+am I not willing to declare peremptorily
+for either of them, again$t the other. And
+indeed, though I have in another Treati$e
+endeavoured to make it probable, that the
+returning of Ela$tical Bodies (if I may $o
+call them) forcibly bent, to their former
+po$ition, may be Mechanically explica-
+ted: Yet I mu$t confe$s, that to deter-
+mine whether the motion of Re$titution
+in Bodies, proceed from this, That the
+parts of a Body of a peculiar Structure
+are put into motion by the bending of the
+$pring, or from the endeavor of $ome $ub-
+tle ambient Body, who$e pa$$age may be
+oppo$'d or ob$tructed, or el$e it's pre$$ure
+unequally re$i$ted by rea$on of the new
+$hape or magnitude, which the bending of
+a Spring may give the Pores of it: To
+determine this, I $ay, $eems to me a mat-
+ter of more difficulty, then at fir$t $ight
+one would ea$ily imagine it. Wherefore
+I $hall decline medling with a $ubject,
+which is much more hard to be explica-
+<pb n=27>
+ted, then nece$$ary to be $o, by him,
+who$e bu$ine$s it is not, in this Letter, to
+a$$ign the adequate cau$e of the Spring of
+the Air, but onely to manife$t, That the
+Air has a Spring, and to relate $ome of
+its effects.
+<p>I know not whether I need annex that,
+though either of the above-mention'd
+Hypothe$es, and perhaps $ome others,
+may afford us an account plau$ible enough
+of the Air-$pring; yet I doubt, whether
+any of them gives us a $ufficient account
+of its Nature. And of this doubt, I
+might here mention $ome Rea$ons, but
+that, peradventure, I may (God permit-
+ting) have a fitter occa$ion to $ay $ome-
+thing of it el$ewhere. And therefore I
+$hould now proceed to the next Experi-
+ment, but that I think it requi$ite, fir$t,
+to $ugge$t to your Lord$hip what comes
+into my thoughts, by way of An$wer to
+a plau$ible Objection, which I fore$ee you
+may make again$t our propo$'d Doctrine,
+touching the Spring of the Air. For it
+may be alleadged, that though the Air
+were granted to con$i$t of Springy Par-
+ticles (if I may $o $peak) yet thereby
+we could onely give an account of the
+Dilatation of the Air in Wine-Guns and
+<pb n=28>
+other pneumatical Engines wherein the
+Air has been compre$$'d, and its Springs
+violently bent by an apparent externall
+force; upon the removall of which, 'tis
+no wonder that the Air $hould, by the
+motion of re$titution, expand it $elf till
+it have recovered its more natural dimen-
+$ions: whereas in our above-mentioned
+fir$t Experiment, and in almo$t all others
+tryable in our Engine, it appears not
+that any compre$$ion of the Air prece-
+ded its $pontaneous Dilatation or Expan-
+$ion of it $elf. To remove this difficul-
+ty, I mu$t de$ire Your Lord$hip to take
+notice, that of whatever nature the Air,
+very remote from the Earth, may be, and
+whatever the Schools may confidently
+teach to the contrary, yet we have divers
+Experiments to evince, that the Atmo$-
+phere we live in is not (otherwi$e then
+comparatively to more ponderous Bodies)
+light, but heavy: And did not their
+gravity hinder them, it appears not why
+the $teams of the Terraqueous Globe, of
+which our Air in great part con$i$ts,
+$hould not ri$e much higher then the Re-
+fraction of the Sun, and other Stars
+give men ground to think, that the At-
+mo$phere, even in the judgement of tho$e
+<pb n=29>
+Recent A$tronomers, who $eem willing
+to enlarge its bounds as much as they dare,
+does reach.
+<p>But le$t you $hould expect my $econding
+this Rea$on by Experience; and le$t you
+$hould object, That mo$t of the Experi-
+m&etilde;ts that have been propo$'d to prove the
+gravity of the Air, have been either barely
+propo$'d, or perhaps not accuratly try'd; I
+am content, before I pa$s further, to menti-
+on here, That I found a dry lambs-bladder
+containing near about two thirds of a pint,
+and compre$$'d by a packthred tyed about
+it, to loo$e a grain and the eighth part of
+a grain of its former weight, by the rece$s
+of the Air upon my having prickt it: And
+this with a pair of Scales, which when the
+full Bladder and the corre$pondent weight
+were in it, would manife$tly turn either
+way with the 32 part of a grain. And if
+it be further objected, That the Air in
+the Bladder was violently compre$$'d by
+the Pack-thred and the $ides of the
+Bladder, we might probably (to wave
+prolix an$wers) be furni$h'd with a Re-
+ply, by $etting down the differing weight
+of our Receiver, when empty'd and when
+full of uncompre$$'d Air, if we could here
+procure $cales fit for $o nice an experiment;
+<pb n=30>
+$ince we are informed, that in the <I>German</I>
+Experiment, commended at the begin-
+ning of this Letter, the Ingenious Tryers
+of it found, That their Gla$s Ve$$el, of
+the capacity of 32 mea$ures, was lighter
+when the Air had been drawn out of it,
+then before, by no le$s then one ounce
+and (3/10) that is, an ounce and very near a
+third: But of the gravity of the Air, we
+may el$ewhere have occa$ion to make fur-
+ther mention.
+<p>Taking it then for granted that the Air
+is not deyoid of weight, it will not be
+unea$ie to conceive, that that part of the
+Atmo$phere wherein we live, being the
+lower part of it, the Corpu$cles that com-
+po$e it, are very much compre$$'d by the
+weight of all tho$e of the like nature that
+are directly over them, that is, of all the
+Particles of Air, that being pil'd up up-
+on them, reach to the top of the Atmo$-
+phere. And though the height of this
+Atmo$phere, according to the famous
+<I>Kepler,</I> and $ome others, $carce exceeds
+eight common miles; yet other eminent
+and later A$tronomers, would promote
+the confines of the Atmo$phere, to ex-
+ceed $ix or $even times t<*> number of
+miles. And the diligent and learned
+<pb n=31>
+<I>Riviolo</I> makes it probable, that the At-
+mo$phere may, at lea$t in divers places, be
+at lea$t 50 miles high. So that according to
+a moderate e$timate of the thickne$s of
+the Atmo$phere, we may well $uppo$e,
+that a Column of Air, of many miles in
+height, leaning upon $ome $pringy Cor-
+pu$cles of Air here below, may have
+weight enough to bend their little $prings,
+and keep them bent: As, to re$ume our
+former compari$on, if there were fleeces of
+Wooll pil'd up to a mountainous height
+upon one another, the Hairs that com-
+po$e the lowermo$t locks which $upport
+the re$t, would, by the weight of all the
+Wool above them, be as well $trongly
+compre$$ed, as if a man $hould $queeze
+them together in his hands, or imploy any
+$uch other moderate force to compre$s
+them. So that we need not wonder, that
+upon the taking off the incumbent Air
+from any parcel of the Atmo$phere here
+below, the Corpu$cles, whereof that un-
+dermo$t Air con$i$ts, $hould di$play them-
+$elves, and take up more room then be-
+fore.
+<p>And if it be objected, That in Water,
+the weight of the upper and of the lower
+part is the $ame: I an$wer, That be$ides
+<pb n=32>
+that it may be well doubted whether the
+ob$ervation, by rea$on of the great diffi-
+culty have been exactly made, there is a
+manife$t di$parity betwixt the Air and
+Water: For I have not found, that upon
+an Experiment purpo$ely made, (and in
+another Treati$e Recorded) that Water
+will $uffer any con$iderable compre$$ion;
+whereas we may ob$erve in Wind-Guns
+(to mention now no other Engines) that
+the Air will $uffer it $elf to be crouded in-
+to a comparatively very little room; in
+$o much, that a very diligent Examiner
+of the <I>Ph&aelig;nomena</I> of Wind-Guns would
+have us believe, that in one of them, by
+conden$ation, he reduc'd the Air into a
+$pace at lea$t eight times narrower then it
+before po$$e$t. And to this, if we adde
+a noble <I>Ph&aelig;nomenon</I> of the Experiment
+<I>De Vacuo;</I> the$e things put together, may
+for the pre$ent $uffice to countenance our
+Doctrine. For that noble Experimenter,
+Mon$ieur <I>Pa$cal</I> (the Son) had the com-
+mendable Curio$ity to cau$e the <I>Torri-
+cellian</I> Experiment to be try'd at the foot,
+about the middle, and at the top of that
+high Mountain (in <I>Auvergne,</I> if I mi$take
+not) commonly call'd <I>Le Puy de Domme;</I>
+whereby it was found, That the <I>Mercury</I>
+<pb n=33>
+in the Tube fell down lower, about three
+inches, at the top of the Mountain then
+at the bottom. And a Learned Man a
+while $ince inform'd me, That a great
+<I>Virtuo$o,</I> friend to us both, has, with not
+unlike $ucce$s, tryed the $ame Experi-
+ment in the lower and upper parts of a
+Mountain in the We$t of <I>England:</I> Of
+which, the rea$on $eems manife$tly enough
+to be this, That upon the tops of high
+Mountains, the Air which bears again$t
+the re$tagnant Quick-$ilver, is le$s pre$$'d
+by the le$s ponderous incumbent Air; and
+con$equently is not able totally to hinder
+the de$cent of $o tall and heavy a Cylin-
+der of Quick-$ilver, as at the bottom of
+$uch Mountains did but maintain an <I>&AElig;qui-
+librium</I> with the incumbent Atmo$phere.
+<p>And if it be yet further Objected a-
+gain$t what hath been propo$'d touching
+the compactne$s and pre$$ure of the Infe-
+rior Air; That we finde this very Air to
+yield readily to the motion of little Flies,
+and even to that of Feathers, and $uch o-
+ther light and weak Bodies; which $eems
+to argue, that the particles of our Air are
+not $o compre$$'d as we have repre$ented
+them, e$pecially, $ince by our former
+Experiment it appears, that the Air rea-
+<pb n=34>
+dily dilated it $elf downward, from the
+Receiver into the Pump, when 'tis plain,
+that it is not the incumbent Atmo$phere,
+but onely the $ubjacent Air in the bra$s
+Cylinder that has been remov'd: If this,
+I $ay, be objected, we may reply, That
+when a man $queezes a Fleece of Wool in
+his hand, he may feel that the Wool in-
+ce$$antly bears again$t his hand, as that
+which hinders the hairs it con$i$ts of, to
+recover their former and more natural ex-
+tent. So each parcel of the Air about the
+Earth, does con$tantly endeavour to thru$t
+away all tho$e contiguous Bodies, whe-
+ther A&euml;rial or more gro$s, that keep
+them bent, and hinder the expan$ion of
+its parts, which will dilate them$elves or
+flie abroad towards that part, whether up-
+wards or downwards, where they finde
+their attempted Dilatation of them$elves
+le$s re$i$ted by the neihgboring Bodies.
+Thus the Corpu$cles of that Air we have
+been all this while $peaking of, being un-
+able, by rea$on of their weight, to a$cend
+above the Convexity of the Atmo$phere,
+and by rea$on of the re$i$tance of the $ur-
+face of the Earth and Water, to fall down
+lower, they are forced, by their own gra-
+vity and this re$i$tance, to expand and
+<pb n=35>
+diffu$e them$elves about the Terre$tial
+Globe; whereby it comes to pa$s, that
+they mu$t as well pre$s the contiguous
+Corpu$cles of Air that on either $ide op-
+po$e their Dilatation, as they mu$t pre$s
+upon the $urface of the Earth, and, as it
+were recoyling thence, endeavor to thru$t
+away tho$e upper particles of Air that
+lean upon them.
+<p>And as for the ea$ie yielding of the Air
+to the Bodies that move in it, if we con-
+$ider that the Corpu$cles whereof it con-
+$i$ts, though of a $pringy nature, are yet
+$o very $mall, as to make up (which 'tis
+manife$t they doe) a fluid Body, it will
+not be difficult to conceive, that in the
+Air, as in other Bodies that are fluid, the
+little Bodies it con$i$ts of are in an almo$t
+re$tle$s motion, whereby they become
+(as we have more fully di$cour$ed in ano-
+<MARG><I>In a Di$-
+cour$e
+touching
+$luidity
+and firm-
+ne$s.</I></MARG>
+ther Treati$e) very much di$po$ed to
+yield to other Bodies, or ea$ie to be di$-
+plac'd by them, and that the $ame Cor-
+pu$cles are likewi$e $o variou$ly mov'd, as
+they are intire Corpu$cles, that if $ome
+$trive to pu$h a Body plac'd among them
+towards the right hand (for in$tance)
+others, who$e motion has an oppo$ite de-
+termination, as $trongly thru$t the $ame
+<pb n=36>
+Body towards the left; whereby neither
+of them proves able to move it out of
+its place, the pre$$ure on all hands being
+reduced as it were to an <I>&AElig;quilibrium:</I> $o
+that the Corpu$cles of the Air mu$t be as
+well $ometimes con$idered under the no-
+tion of little Springs, which remaining
+bent, are in their entire bulk tran$ported
+from place to place; as under the notion
+of Springs di$playing them$elves, who$e
+parts flie abroad whil$t as to their entire
+bulk they $carce change place: As the
+two ends of a Bow, $hot off, fly from one
+another, whereas the Bow it $elf may be
+held fa$t in the Archers hand; and that it
+is the equal pre$$ure of the Air on all $ides
+upon the Bodies that are in it, which cau-
+$es the ea$ie Ce$$ion of its parts, may be
+argu'd from hence: That if by the help
+of our Engine the Air be but in great
+part, though not totally drawn away
+from one $ide of a Body without being
+drawn away from the other; he that $hall
+think to move that Body too and fro, as
+ea$ily as before, will finde him$elf much
+mi$taken.
+<p>In verification of which we will, to di-
+vert your Lord$hip a little, mention here
+a <I>Ph&aelig;nomenon</I> of our Engine, which even
+<pb n=37>
+to divers ingenious per$ons has at fir$t
+$ight $eem'd very wonderful.
+<p>THe thing that is wont to be admired,
+<MARG><I>Experi-
+ment</I> 2.</MARG>
+and which may pa$s for our $econd
+Experiment is this, That if, when the
+Receiver is almo$t empty, a By-$tander
+be de$ired to lift up the bra$s Key (former-
+ly de$cribed as a $topple in the bra$s Co-
+ver) he will finde it a very difficult thing
+to do $o, if the Ve$$el be well exhau$ted;
+and even when but a moderate quantity of
+Air has been drawn out, he will, when he
+has lifted it up a little, $o that it is $ome-
+what loo$e from the $ides of the lip or
+$ocket, which (with the help of a little
+oyl) it exactly filled before, he will (I $ay)
+finde it $o difficult to be lifted up, that
+he will imagine there is $ome great weight
+fa$tned to the bottom of it. And if (as
+$ometimes has been done for merriment)
+onely a Bladder be tyed to it, it is plea-
+$ant to $ee how men will marvail that $o
+light a Body, filled at mo$t but with Air,
+$hould $o forcibly draw down their hand
+as if it were fill'd with $ome very ponder-
+ous thing: whereas the cau$e of this pret-
+ty <I>Ph&aelig;nomenon</I> $eems plainly enough to
+<pb n=38>
+be onely this, That the Air in the Recei-
+ver, being very much dilated, its Spring
+mu$t be very much weakn'd, and con$e-
+quently it can but faintly pre$s up the
+lower end of the $topple, whereas the
+Spring of the external Air being no way
+debilitated, he that a little lifts up the
+$topple mu$t with his hand $upport a pre$-
+$ure equal to the di$proportion betwixt
+the force of the internal expanded Air, and
+that of the Atmo$phere incumbent upon
+the upper part of the $ame key or $topple:
+And $o men being unu$'d to finde any re-
+$i$tance, in lifting things up, from the
+free Air above them, they are forward to
+conclude that that which depre$$es their
+hands mu$t needs be $ome weight, though
+they know not where plac'd, drawing be-
+neath it.
+<p>And that we have not mi$-a$$ign'd the
+cau$e of this <I>Ph&aelig;nomenon</I> $eems evident
+enough by this; That as Air is $uffer-
+ed by little and little to get into the Re-
+ceiver, the weight that a man fancies his
+hand $upports is manife$tly felt to decrea$e
+more and more, the internal Air by this
+recruit approaching more to an <I>&AElig;quili-
+brium</I> with the external, till at length the
+Receiver growing again full of Air, the
+<pb n=39>
+$topple may be lifted up without any dif-
+ficulty at all.
+<p>By $everal other of the Experiments
+afforded us by our Engine, the $ame no-
+tion of the great and equal pre$$ure of the
+free Air upon the Bodies it environs,
+might be here manife$ted, but that we
+think it not $o fit to anticipate $uch Ex-
+periments: And therefore $hall rather
+employ a few lines to clear up a difficulty
+touching this matter, which we have ob-
+$erv'd to have troubled $ome even of the
+Philo$ophical and Mathematical Specta-
+tors of our Engine, who have wonder'd
+that we $hould talk of the Air exqui$itely
+$hut up in our Receiver, as if it were all
+one with the pre$$ure of the Atmo$phere;
+whereas the thick and clo$e body of the
+Gla$s, wholly impervious to the Air, does
+manife$tly keep the incumbent Pillar of
+the Atmo$phere from pre$$ing in the lea$t
+upon the Air within the Gla$s, which it
+can no where come to touch. To eluci-
+date a little this matter, let us con$ider,
+That if a man $hould take a fleece of
+Wool, and having fir$t by compre$$ing it
+in his hand reduc'd it into a narrower com-
+pa$s, $hould nimbly convey and $hut it
+clo$e up into a Box ju$t fit for it, though
+<pb n=40>
+the force of his hand would then no lon-
+ger bend tho$e numerous $pringy Body's
+that compo$e the Fleece, yet they would
+continue as $trongly bent as before, be-
+cau$e the Box they are inclo$'d in would
+as much re$i$t their re-expanding of
+them$elves, as did the hand that put them
+in. For thus we may conceive, that the
+Air being $hut up, when its parts are bent
+by the whole weight of the incumbent
+Atmo$phere, though that weight can no
+longer lean upon it, by rea$on it is kept
+off by the Gla$s, yet the Corpu$cles of
+the Air within that Gla$s continue as
+forcibly bent as they were before their in-
+clu$ion, becau$e the $ides of the Gla$s
+hinder them from di$playing or $tretch-
+ing out them$elves. And if it be ob-
+jected that this is unlikely, becau$e ev'n
+Gla$s bubles, $uch as are wont to be
+blown at the flame of a Lamp, exceeding
+thin and Hermetically $eal'd will not
+break; whereas it cannot be imagin'd
+that $o thin a Pri$on of Gla$s could re-
+$i$t the Ela$tical force of all the included
+Air, if that Air were $o compre$$'d as we
+$uppo$e. It may be ea$ily reply'd, That
+the pre$$ure of the inward Air again$t the
+Gla$s, is countervail'd by the equal pre$-
+<pb n=41>
+$ure of the outward again$t the $ame Gla$s.
+And we $ee in bubles, that by rea$on of
+this an exceeding thin film of Water is
+often able, for a good while, to hinder the
+eruption of a pretty quantity of Air. And
+this may be al$o more con$picuous in
+tho$e great Spherical bubles that boyes
+$ometimes blow with Water, to which
+Sope has given a Tenacity. But that, if the
+pre$$ure of the ambient Air were remov'd,
+the internal Air may be able to break
+thicker Gla$$es then tho$e lately men-
+tion'd, will appear by $ome of the follow-
+ing Experiments; to which we $hall there-
+fore now ha$ten, having, I fear, been but
+too prolix in this Excur$ion, though we
+thought it not ami$s to annex to our fir$t
+Experiments $ome general Con$iderati-
+ons touching the Spring of the Air, be-
+cau$e (this Doctrine being yet a $tranger
+to the Schools) not onely we finde not
+the thing it $elf to be much taken notice
+of; but of tho$e few that have heard of it,
+the greater part have been forward to re-
+ject it, upon a mi$taken Per$wa$ion, that
+tho$e <I>Ph&aelig;nomena</I> are the effects of natures
+abhorrency of a <I>Vacuum,</I> which $eem to
+be more fitly a$cribeable to the weight
+and Spring of the Air.
+<pb n=42>
+<p>WE will now proceed to ob$erve that
+<MARG><I>Experi-
+ment</I> 3.</MARG>
+though, by the help of the handle,
+the Sucker be ea$ily drawn down to the
+bottom of the Cylinder; yet, without
+the help of that Leaver, there would be
+required to the $ame effect, a force or
+weight great enough to $urmount the
+pre$$ure of the whole Atmo$phere: Since
+otherwi$e the Air would not be driven out
+of its place, when none is permitted to
+$ucceed into the place de$erted by the
+Sucker. This $eems evident, from the
+known <I>Torricellian</I> Experiment, in which,
+if the inverted Tube of <I>Mercury</I> be but
+25 Digits high, or $omewhat more, the
+Quick-$ilver will not fall but remain $u$-
+pended in the Tube; becau$e it cannot
+pre$s the $ubjacent <I>Mercury</I> with $o great
+a force, as does the incumbent Cylinder
+of the Air reaching thence to the top of
+the Atmo$phere: Whereas, if the Cy-
+linder of <I>Mercury</I> were three or four digits
+longer, it would over-power that of the
+external Air, and run out into the Ve$$el'd
+<I>Mercury,</I> till the two Cylinders came to
+an <I>&AElig;quilibrium,</I> and no further. Hence
+we need not wonder, that though the
+<pb n=43>
+Sucker move ea$ily enough up and down
+in the Cylinder by the help of the <I>Manu-
+brium;</I> yet if the <I>Manubrium</I> be taken off,
+it will require &amp; con$iderable $trength to
+move it either way. Nor will it $eem
+$trange, that if, when the Valve and
+Stop-cock are well $hut, you draw down
+the Sucker, and then let go the <I>Manubri-
+um;</I> the Sucker will, as it were of it $elf,
+re-a$cend to the top of the Cylinder, $ince
+the $pring of the external Air findes no-
+thing to re$i$t its pre$$ing up the Sucker.
+And for the $ame rea$on, when the Re-
+ceiver is almo$t evacuated, though, ha-
+ving drawn down the Sucker, you open
+the way from the Receiver to the Cylin-
+der, and then intercept that way again by
+returning the Key; the Sucker will, up-
+on the letting go the <I>Manubrium,</I> be
+forcibly carried up almo$t to the top of
+the Cylinder: Becau$e the Air within the
+Cylinder, being equally dilated and weak-
+ned with that of the Gla$s, is unable to
+with$tand the pre$$ure of the external Air,
+till it be driven into $o little $pace, that
+there is an <I>&AElig;quilibrium</I> betwixt its force
+and that of the Air without. And con-
+gruou$ly hereunto we finde, that in this
+ca$e, the Sucker is drawn down with little
+<pb n=44>
+le$s difficulty, then if the Cylinder, be-
+ing devoid of Air, the Stop-cock were
+exactly $hut: We might take notice of
+$ome other things, that depend upon the
+Fabrick of our Engine it $elf; but to $hun
+prolixity, we will, in this place, content
+our $elves to mention one of them, which
+$eems to be of greater moment then the
+re$t, and it is this; that when the Sucker
+has been impell'd to the top of the Cylin-
+der, and the Valve is $o carefully $topp'd,
+that there is no Air left in the Cylinder a-
+bove the Sucker: If then the Sucker be
+drawn to the lower part of the Cylinder,
+he that manages the Pump findes not any
+$en$ibly greater difficulty to depre$s the
+Sucker, when it is nearer the bottom of the
+Cylinder, then when it is much further off.
+Which circum$tance we therefore think fit
+to take notice of, becau$e an eminent Mo-
+dern Naturali$t hath taught, that, when the
+Air is $ucked out of a Body, the violence
+wherewith it is wont to ru$h into it again,
+as $oon as it is allow'd to re-enter, pro-
+ceeds mainly from this; That the pre$$ure
+of the ambient Air is $trengthned upon
+the acce$$ion of the Air $uck'd out; which,
+to make it $elf room, forces the neighbor-
+ing Air to a violent-$ubingre$$ion o$ its
+parts: which, i$ it were true, he that draws
+<pb n=45>
+down the Sucker, would finde the re$i$t-
+ance of the external Air increa$'d as he
+draws it lower, more of the di$placed Air
+being thru$t into it to compre$s it. But, by
+what has been di$cour$'d upon the fir$t
+Experiment, it $eems more probable, that
+without any $uch $trengthning of the pre$-
+$ure of the outward Air, the taking quite
+away or the debilitating of the re$i$tance
+from within, may $uffice to produce the
+effects under con$ideration. But this will
+perhaps be illu$trated by $ome or other of
+our future Experiments, and therefore
+$hall be no longer in$i$ted on here.
+<p>HAving thus taken notice of $ome of
+<MARG><I>Experi-
+ment</I> 4.</MARG>
+the con$tant <I>Ph&aelig;nomena</I> of our En-
+gine it $elf, let us now proceed to the Ex-
+periments tryable in it.
+<p>We took then a Lambs Bladder large,
+well dry'd, and very limber, and leaving in
+it about half as much Air as it could con-
+tain, we cau$'d the neck of it to be $trong-
+ly ty'd, $o that none of the included Air,
+though by pre$$ure, could get out. This
+Bladder being convey'd into the Receiver,
+and the Cover luted on, the Pump
+was $et awork, and after two or three
+ex$uctions of the ambient Air (where-
+by the Spring of that which remain'd in
+<pb n=46>
+the Gla$s was weaken'd) the Impri$on'd
+Air began to $well in the Bladder, and as
+more and more of the Air in the Recei-
+ver was, from time to time, drawn out; $o
+did that in the Bladder more and more ex-
+pand it $elf, and di$play the folds of the
+formerly flaccid Bladder: $o that before we
+had exhau$ted the Receiver near $o much
+as we could, the Bladder appear'd as full
+and $tretched, as if it had been blown up
+with a Quill.
+<p>And that it may appear that this plump-
+ne$s of the Bladder proceeded from the
+$urmounting of the debilitated Spring of
+the ambient Air remaining in the Ve$$el,
+by the $tronger Spring of the Air remain-
+ing in the Bladder; we Return'd the Key
+of the Stop-cock, and by degrees allow'd
+the external Air to return into the Recei-
+ver: Whereupon it happen'd, as was ex-
+pected, that as the Air came in from with-
+out, the di$turb'd Air in the Bladder, was
+proportionably compre$$'d into a narrow-
+er room, and the $ides of the Bladder
+grew flaccid, till the Receiver having re-
+admitted its wonted quantity of Air, the
+Bladder appear'd as full of wrinkles and
+cavities as before.
+<pb n=47>
+<p>This Experiment is much of the $ame
+nature with that which was $ome years
+agoe $aid to be made by that eminent Ge-
+ometrician Mon$ieur <I>Roberval,</I> with a
+Carps Bladder empty'd and convey'd into
+a Tube, wherein the Experiment <I>De Va-
+cuo</I> was afterwards try'd, which ingeni-
+ous Experiment of his ju$tly de$erves the
+thanks of tho$e that have been, or $hall be
+$olicitous to di$cover the nature of the
+Air.
+<p>But to return to our Experiment, we
+may take notice of this Circum$tance in
+it, That after the Receiver has been in
+$ome mea$ure empty'd, the Bladder do's,
+at each ex$uction, $well much more con-
+$picuou$ly then it did at any of the fir$t
+Ex$uctions; in$omuch that towards the
+end of the pumping, not onely a great
+fold or cavity in the $urface of the Blad-
+der may be made, even by the $tretching
+of the inward $elf-expanding Air: But
+we have $ometimes $een, upon the turn-
+ing of the Key to let the ambient Air
+pa$s out of the Receiver into the Cylin-
+der, we have $een (I $ay) the Air in the
+Bladder $uddenly expand it $elf $o much
+and $o briskly, that it manife$tly lifted up
+$ome light Bodies that lean'd upon it,
+<pb n=48>
+and $eem'd to lift up the Bladder it
+$elf.
+<p>Now becau$e it has by very Learned
+Men been doubted whether the $welling
+of the Bladder may not have proceeded
+from the Dilatation of the included Air,
+but from the Texture of the Fibres,
+which, being wont to keep the Bladder
+extended when the Animal to whom it
+belong'd was alive, may be $uppo$'d in
+our Experiment to have return'd, like $o
+many Springs to their wonted extent, up-
+on the removal of the Ambient Air that
+compre$$'d and bent them: becau$e this,
+I $ay, has been doubted, we thought fit
+to make this further tryall.
+<p>We let down into the Receiver with
+the fore-mentioned Bladder two other
+much $maller, and of the $ame kinde of
+Animal; the one of the$e was not ty'd
+up at the neck that there might be liberty
+left to the Air that was not $queez'd out
+(which might amount to about a fifth
+part of what the Bladder held before) to
+pa$s out into the Receiver: The other had
+the $ides of it $tretch'd out and pre$$'d to-
+gether, almo$t into the form of a Cup,
+that they might intercept the le$s Air be-
+twixt them, and then was $trongly ty'd
+<pb n=49>
+up at the neck: This done, and the Air
+being in $ome mea$ure $uck'd out of the
+Pneumatical Gla$s (if I may $o call it)
+the Bladder, mention'd at the beginning
+of our Experiment, appear'd extended e-
+very way to its full Dimen$ions; whereas
+neither of the two others did remarkably
+$well, and that who$e neck was not ty'd
+$eem'd very little, if at all le$s wrinkl'd
+then when it was put in.
+<p>We made likewi$e a $trong Ligature a-
+bout the middle of a long Bladder part-
+ly empty'd, and upon the drawing the
+Air out of the Receiver, could ob$erve
+no $uch $welling betwixt the Ligature and
+the Neck of the Bladder, which had been
+purpo$ely left open, as betwixt the $ame
+Ligature and the bottom of the Bladder,
+whence the included Air could no way
+get out.
+<p>But a further and $ufficient manife$tati-
+on whence the intume$$ence of the Blad-
+der proceeds, may be deduc'd from the
+following Experiment.
+<p>TO try then at once both what it was
+<MARG><I>Experi-
+ment</I> 5.</MARG>
+that expanded the Bladder, and what
+a powerful Spring there is ev'n in the Air
+<pb n=50>
+we are wont to think uncompre$$'d, we
+cau$'d a Bladder dry, well ty'd and blown
+moderately full, to be hung in the Recei-
+ver by one end of a $tring, who$e other
+end was fa$tned to the in$ide of the Co-
+ver: and upon drawing out the ambient
+Air, that pre$$'d on the Bladder; the in-
+ternal Air not finding the wonted re$i$t-
+ance, fir$t $well'd and di$tended the Blad-
+der, and then broke it, with $o wide and
+crooked a rent, as if it had been forcibly
+torn a$$under with hands. After which a
+$econd Bladder being convey'd in, the Ex-
+periment was repeated with like $ucce$s:
+And I $uppo$e it will not be imagin'd that
+in this ca$e the Bladder was broken by its
+own Fibres, rather then by the Impri-
+$on'd Air.
+<p>And of this Experiment the$e two <I>Ph&aelig;-
+nomena</I> may be taken notice of: The one,
+that the Bladder at its breaking gave a
+great report, almo$t like a Craker: And
+the other, That the Air contain'd in the
+Bladder, had the power to break it with
+the mention'd Impetuo$ity, long before
+the ambient Air was, all or near all, drawn
+out of the Receiver.
+<p>But, to verifie what we $ay in another
+Di$cour$e, where we $how, That even
+<pb n=51>
+true Experiments may, by rea$on of
+the ea$ie mi$take of $ome unheeded
+Circum$tance, be un$ucce$sfully try'd;
+we will Adverti$e, on this occa$ion,
+that we did oftentimes in vain try the
+breaking of Bladders, after the manner
+above-mention'd: Of which the cau$e
+appear'd to be this, That the Bladders we
+could not break, having been brought us
+ready blown from tho$e that $old them,
+were grown dry before they came to our
+hands: whence it came to pa$s, that, if
+we afterwards ty'd them very hard, they
+were apt to fret and $o become un$ervice-
+able; and if we ty'd them but moderate-
+ly hard, their $tiffne$s kept them from be-
+ing clo$'d $o exactly, but that when the
+included Air had in the exhau$ted Recei-
+ver di$tended them as much as ea$ily it
+could, it would in part get out between
+the little wrinkles of the Sphincter of the
+Neck: Whence al$o it u$ually happen'd,
+that, upon the letting in the Air from
+without, the Bladders appear'd more flac-
+cid and empty then before they were put
+in; whereas when the Bladders were
+brought us moi$t from the Butchers, we
+could, without injuring them, tye their
+necks $o clo$e, that none of the Air once
+<pb n=52>
+blown in, could get out of them, but by
+violently breaking them.
+<p>It will not be ami$s on this occa$ion to
+point at $omething which may de$erve a
+more deliberate Speculation then we can
+now afford it; namely that the Ela$tical
+Power of the $ame Quantity of Air may
+be as well Encrea$'d by the Agitation of
+the A&euml;rial Particles (whether onely mo-
+ving them more $wiftly and $cattering
+them, or al$o extending or $tretching
+them out, I determine not) within an
+every way inclo$ing and yet yielding Bo-
+dy; as Di$play'd by the withdrawing of
+the Air that pre$$'d it without. For we
+found that a Bladder, but moderately
+fill'd with Air and $trongly ty'd, being
+a while held near the Fire, not onely grew
+exceeding turgid and hard, but after-
+wards, being approach'd nearer to the
+Fire, $uddenly broke with $o loud and ve-
+hement a noi$e, as $tony'd tho$e that were
+by, and made us, for a while after, almo$t
+deaf.
+<p>HAving thus $een that the Air has an
+<MARG><I>Experi-
+ment</I> 6.</MARG>
+Ela$tical Power, we were next de$i-
+rous to know in $ome mea$ure how far a
+<pb n=53>
+parcel of Air might by this its own Spring
+be dilated. And though we were not pro-
+vided of In$truments fit to mea$ure the
+dilatation of the Air any thing accurately,
+yet becau$e an imperfect mea$ure of it was
+more de$ireable then none at all, we de-
+vi$'d the following Method as very ea$ily
+practicable.
+<p>We took a limber Lambs Bladder
+which was thorowly wetted in fair Water,
+that the $ides of it being $queez'd roge-
+ther, there might be no Air left in its
+folds: (as indeed we could not afterwards
+upon tryal di$cern any) The neck of this
+Bladder was $trongly tyed about that of
+a $mall Gla$s, (capable of holding five
+full drachmes of Water) the Bladder be-
+ing fir$t $o compre$$'d, that all the inclu-
+ded Air was onely in the Gla$s, without
+being pre$$'d there; then the Pump be-
+ing $et awork after a few ex$uctions, the
+Air in the little Viol began to dilate it
+$elf and produce a $mall Tumor in the
+Neck of the Bladder; and as the ambi-
+ent Air was more and more drawn away,
+$o the included Air penetrated further and
+further into the Bladder, and by degrees
+lifted up the $ides and di$play'd its folds,
+till at length it $eem'd to have blown it
+<pb n=54>
+up to its full extent: whereupon the ex-
+ternal Air, being permitted to flow back
+into the Reciver, repul$'d the Air that
+had fill'd the Bladder into its former nar-
+row receptacle, and brought the Bladder
+to be again flaccid and wrinkled as before:
+Then taking out the Bladder, but with-
+out $evering it from the Gla$s, we did by
+a hole made at the top of the Bladder fill
+the Ve$$el they both made up with Wa-
+ter, who$e weight was five Ounces five
+Drachmes and an half: Five Drachmes
+whereof were above-mention'd to be the
+contents of the Bottle. So that in this Ex-
+periment, when the Air had mo$t extend-
+ed the Bladder, it po$$e$$'d in all above
+nine times as much room as it did when it
+was put into the Receiver. And it would
+probably have much inlarg'd its bounds,
+but that the Bladder by its weight and the
+$ticking together of its $ides did $ome-
+what re$i$t its expan$ion: And which was
+more con$iderable, the Bladder appear'd
+tumid enough, whil$t yet a pretty deal of
+Air was left in the Receiver, who$e ex-
+$uction would, according to our former
+Ob$ervation, probably have given way
+to a further expan$ion of the Air, e$peci-
+<pb n=55>
+ally $uppo$ing the dilatation not to be re-
+$train'd by the Bladder.
+<p>SInce we wrote the other day the former
+Experiment, we have met with $ome
+Gla$$es not very unfit for our purpo$e;
+by means of which we are now able, with
+a little more trouble, to mea$ure the ex-
+pan$ion of the Air a great deal more ac-
+curately then we could by the help of the
+above-mention'd Bladder, which was
+much to narrow to allow the Air its ut-
+mo$t di$tention.
+<p>We took then fir$t a Cylindrical Pipe
+of Gla$s, who$e bore was about a quarter
+of an Inch in Diameter: this Pipe was $o
+bent and doubled, that, notwith$tanding
+its being about two foot in length, it
+might have been $hut up into a $mall Re-
+ceiver, not a Foot high: But by mi$-
+fortune it crack'd in the cooling, whereby
+we were reduced to make u$e of one part
+which was $traight and intire, but exceed-
+ed not $ix or $even Inches. This little
+Tube was open at one end; and at the
+other, where it was Hermetically $eal'd,
+had a $mall Gla$s bubble to receive the
+Air who$e dilatation was to be mea$ur'd.
+<pb n=56>
+<p>Along the $ide of this Tube was pa$t-
+ed a $traight narrow piece of Parchment,
+divided into twenty $ix equal parts, mark-
+ed with black Lines and Figures, that by
+them might be mea$ur'd both the inclu-
+ded Air and its dilatation. Afterwards
+we fill'd the Tube with Water almo$t to
+the top, and $topping the open end with
+a Finger, and inverting the Tube, the
+Air was permitted to a$cend to the above-
+mention'd Gla$s bubble. And by rea-
+$on this a$cent was very $low, it gave us
+the opportunity to mark how much more
+or le$s then one of the twenty $ix divi$i-
+ons this Air took up. By this means, af-
+ter a tryal or two, we were inabled to con-
+vey to the top of the Gla$s a bubble of
+Air equal enough, as to $ight, to one
+of tho$e Divi$ions: Then the open end
+of the Tube being put into a $mall Viol,
+who$e bottom was cover'd with Water
+about half an Inch high; we included
+both Gla$$es into a $mall and $lender Re-
+ceiver, and cau$ed the Pump to be $et a-
+work. The event was, That at the fir$t
+ex$uction of the Air there appear'd not
+any expan$ion of the bubble, comparable
+to what appear'd at the $econd, and that
+upon a very few ex$uctions the bubble
+<pb n=57>
+reaching as low as the $urface of the $ub-
+jacent Water, gave us cau$e to think
+that if our Pipe had not been broken it
+would have expanded it $elf much fur-
+ther: Wherefore we took out the little
+Tube, and found that be$ides the twenty
+$ix divi$ions formerly mention'd, the
+Gla$s bubble and $ome part of the Pipe
+to which the divided Parchment did not
+reach, amounted to $ix divi$ions more.
+Whereby it appears that the air had taken
+up one and thirty times as much room as
+before, and yet $eem'd capable of a much
+greater expan$ion, if the Gla$s would
+have permitted it. Wherefore, after the
+former manner, we let in another bubble,
+that by our gue$s was but half as big as
+the former, and found, that upon the ex-
+$uction of the Air from the Receiver, this
+little bubble did not onely fill up the
+whole Tube, but (in part) break through
+the $ubjacent Water in the Viol, and
+thereby manife$t it $elf to have po$$e$$ed
+$ixty and odde times its former room.
+<p>The$e two Experiments are mention'd
+to make way for the more ea$ie belief of
+that which is now to follow. Finding
+then that our Tube was too $hort to $erve
+our turn, we took a $lender Quill of Gla$s
+<pb n=58>
+which happen'd to be at hand, though it
+were not $o fit for our purpo$e as we
+could have wi$hed, in regard it was three
+or four times as big at one end as the o-
+ther. This Pipe which was thirty Inches
+long, being Hermetically $eal'd at the
+$lender end, was almo$t filled with Wa-
+ter; and after the above-related manner
+a bubble was convey'd to the top of it,
+and the open extream was put into a Viol
+that had a little fair Water at the bottom:
+Then the Cover, by means of a $mall hole
+purpo$ely made in it for the Gla$s Pipe to
+$tand out at, was cemented on to the Re-
+ceiver, and the Pump being $et awork,
+after $ome ex$uctions, not onely the Air
+manife$tly appear'd extended below the
+$urface of the $ubjacent Water; but one
+of the By-$tanders affirms, that he $aw
+$ome bubbles come out at the bottom of
+the Pipe and break through the Water
+This done, we left off Pumping, and ob-
+$erv'd how at the unperceiv'd leaks of the
+Receiver the Air got in $o fa$t, thatit
+very quickly impell'd up the Water to
+the top of the Tube, excepting a little
+$pace whereinto that bubble was repul$'d,
+which had $o lately po$$e$$'d the whole
+Tube; this Air at the $lender end ap-
+<pb n=59>
+pear'd to be a Cylinder of 5/6 parts of an
+Inch in length; but when the Pipe was
+taken out and turn'd up$ide down, it ap-
+pear'd at the other end inferior in bulk to a
+Pea.
+<p>The$e things being thus done we took
+(to make the Experiment the more ex-
+actly) a $mall pair of Scales, $uch as Gold-
+Smiths u$e to weigh Gold Coyn in; and
+weighing the Tube and Water in it, we
+found them to amount to one Ounce thir-
+ty Grains and an half: Then we pour'd in
+as much Water as $erv'd to fill up the
+Tube, wherein before we had left as much
+$pace unfill'd up as was po$$e$$'d by the
+bubble; and weighing again the Pipe and
+Water, we found the weight increa$'d
+onely by one Grain. La$tly, pouring out
+the Water, and carefully freeing the Pipe
+from it (which yet we could not perfectly
+doe) we weighed the Gla$s alone, and
+found it to want two Drachmes and thirty
+two Grains of its former weight: So
+that the bubble of Air taking up the room
+but of one Grain in weight of Water, it
+appear'd that the Air by its own <G>e)lith\r</G>
+was $o rarified, as to take up one hundred
+fifty two times as much room as it did be-
+fore: though it were then compre$$'d by
+<pb n=60>
+nothing but the ordinary pre$$ure of the
+contiguous Air. I know not whether it
+be requi$ite to take notice, that this Ex-
+periment was made indeed in a moi$t
+Night, but in a Room, in who$e Chim-
+ney there was burning a good Fire, which
+did perhaps $omewhat rarifie the Air of
+which the bubble con$i$ted.
+<p>It has $eem'd almo$t incredible which is
+related by the Indu$trious <I>Mer$ennus,</I> That
+the Air by the violence of heat, though
+as great as our Ve$$els can $upport with-
+out fu$ion, can be $o dilated as to take up
+$eventy times as much room as before:
+Wherefore becau$e we were willing to
+have a confirmation of $o $trange a <I>Ph&aelig;no-
+menon;</I> we once more convey'd into the
+Tube a bubble of the bigne$s of the for-
+mer, and pro$ecuting the Experiment as
+before with the $ame Water, we ob$erved
+that the Air did manife$tly $tretch it $elf
+$o far, as to appear $everal times a good
+way below the $urface of the Water in the
+Viol, and that too with a $urface very
+convex toward the bottom of the Pipe.
+Nay, the Pump being ply'd a little lon-
+ger, the Air did manife$tly reach to that
+place where the bottom of the Tube
+lean'd upon the bottom of the Viol, and
+<pb n=61>
+$eem'd to knock upon it and rebound
+from it: Which Circum$tances we adde,
+partly that the <I>Ph&aelig;nomenon</I> we have been
+relating may not be imputed to the
+bare $ub$iding of the Water that fill'd
+the Tube, upon the taking off the pre$-
+$ure of the ambient Air. And partly al-
+$o that it may appear that if our Expe-
+riments have not been as accurately made
+as with fitter In$truments might perhaps
+be po$$ible; yet the expan$ion of the
+Air is likely to be rather greater then
+le$$er then we have made it: Since the
+Air was able to pre$s away the Water at
+the bottom of the Pipe, though that were
+about two Inches below the $urface of the
+Water that was then in the Viol, and
+would have been at lea$t as high in the
+Pipe, if the Water had onely $ub$ided and
+not been depre$$ed: So that it $eems not
+unlikely that if the Experiment could be
+$o made, as that the expan$ion of the Air
+might not be re$i$ted by the Neighboring
+Bodies, it would yet inlarge its bounds,
+and perhaps $tretch it $elf to two hundred
+times its former bulk, if not more. How-
+ever, what we have now try'd will, I hope,
+$uffice to hinder divers of the <I>Ph&aelig;nomena</I>
+of our Engine from being di$tru$ted:
+<pb n=62>
+Since in that part of the Atmo$phere we
+live in, that which we call the free Air (and
+pre$ume to be $o uncompre$$'d) is crouded
+into $o very $mall a part of that $pace,
+which if it were not hindred it would po$-
+$e$s. We would gladly have tryed al$o
+whether the Air at its greate$t expan$ion
+could be further rarified by heat; but do
+what we could, our Receiver leak'd too
+fa$t to let us give our $elves any $atisfacti-
+on in that particular.
+<p>TO di$cover likewi$e by the means of
+<MARG><I>Experi-
+ment</I> 7.</MARG>
+that pre$$ure of the Air, both the
+$trength of Gla$s, and how much inte-
+re$t the Figure of a Body may have in its
+greater or le$$er Re$i$tance to the pre$$ure
+of other Bodys, we made the$e further
+tryals.
+<p>We cau$'d to be blown with a Lamp a
+round Gla$s bubble, capable of contain-
+ing, by gue$s, about five Ounces of Wa-
+ter, with a $lender neck about the bigne$s
+of a Swans Quill, and it was purpo$ely
+blown very thin, as Viols made with
+Lamps are wont to be, that the thinne$s
+of the matter might keep the roundne$s
+of the Figure from making the Ve$$el too
+<pb n=63>
+$trong. Then having moderately empty-
+ed the Receiver, and taken it out of the
+Pump, we $peedily applyed to the Ori-
+fice of the bottom of it the Neck of the
+newly mention'd Gla$s, carefully $topping
+the Crannys with melted Plai$ter, that no
+Air might get in at them: And after
+turning the Key of the Stop-cock, we
+made a free pa$$age for the Air to pa$s out
+of the bubble into the Receiver: which it
+did with great celerity, leaving the bub-
+ble as empty as the Receiver it $elf; as ap-
+pear'd to us by $ome Circum$tances not
+now to be in$i$ted on. Notwith$tanding
+all which, the Ve$$el, continuing as intire
+as before, gave us cau$e to wonder that
+the bare Roundne$s of the Figure $hould
+inable a Gla$s, almo$t as thin as Paper, to
+re$i$t $o great a pre$$ure as that of the
+whole incumbent Atmo$phere. And ha-
+ving reiterated the Experiment, we found
+again that the pre$$ure of the ambient
+Body, thru$ting all the parts inwards,
+made them, by rea$on of their arched Fi-
+gure, $o $upport one another, that the
+Gla$s remain'd as whole as at fir$t.
+<p>Now that the Figure of the Gla$s is
+of great moment in this matter, may be
+evinced by this other Experiment.
+<pb n=64>
+<p>WE took a Gla$s Helmet or Alem-
+<MARG><I>Experi-
+ment</I> 8.</MARG>
+bick (delineated by the $eventh
+Figure) $uch as Chymi$ts u$e in Di$tilla-
+tions, and containing by conjecture be-
+tween two and three Pints: The <I>Ro$trum</I>
+or No$e of it mark'd with <I>(c)</I> was Herme-
+tically clo$ed; and at the top of it was a
+hole, into which was fitted and cemented
+one of the Shanks of a middle-$iz'd Stop-
+cock; $o that the Gla$s being turn'd up-
+$ide-down, the wide Orifice (which in
+common Gla$s-Helmets is the onely one)
+was upwards; and to that wide Orifice
+was fitted a ca$t-Cover of Lead, which
+was carefully cemented on to the Gla$s:
+Then the other Shank of the Stop-cock
+being with Cement likewi$e fa$ten'd into
+the upper part of the Pump, the ex$ucti-
+on of the Air was endeavoured. But it
+was not long before, the remaining Air
+being made much too weak to ballance
+the pre$$ure of the ambient Air, the Gla$s
+was not without a great noi$e crack'd al-
+mo$t half round, along that part of it
+where it began to bend inwards: As if
+in the Figure the crack had been made ac-
+cording to the Line <I>(ab);</I> and upon an
+<pb n=65>
+endeavour to pump out more of the Air,
+the crack once began, appear'd to run on
+further; though the Gla$s where it was
+broken $eem'd to be by conjecture above
+ten, $ome thought above twenty times as
+thick as the bubble mention'd in the fore-
+going Experiment.
+<p>This will perhaps make it $eem $trange,
+that having taken another Gla$s bubble
+blown at the $ame time, and like for
+ought we di$cern'd for $ize, thickne$s
+and Figure to that thin one formerly
+mention'd; and having $eal'd it up Her-
+metically, and $u$pended it in the Recei-
+ver, the ex$uction of the ambient Air did
+not enable the impri$oned Air to break, or
+in the lea$t to crack the bubble; though
+the Experiment were laboriou$ly try'd,
+and that $everal times with bubbles of o-
+ther $izes: But that perhaps the heat of
+the Candle or Lamp wherewith $uch
+Gla$$es are Hermetically $eal'd, (not to
+mention the warmth of his hands that
+$eal'd it) might $o rarifie the contained
+Air, as much to weaken its Spring, may
+$eem probable by the following Expe-
+riments.
+<pb n=66>
+<p>WE took a Gla$s Viol able to hold
+<MARG><I>Experi-
+ment</I> 9.</MARG>
+three or four Ounces of Water,
+and of the thickne$s u$ual in Gla$$es of
+that $ize; into the Neck of this was put
+a moderately $lender Pipe of Gla$s, which
+was carefully fa$ten'd with a mixture of e-
+qual parts of Pitch and Ro$in to the Neck
+of the Viol, and which reach'd almo$t to
+the bottom of it, as the $ixth Figure de-
+clares.
+<p>This Viol being upon a particular de-
+$ign fill'd with Water, till that came up in
+it a pretty deal higher then the lower end
+of the Pipe, was put into one of our $mall
+Receivers, (containing between a Pint
+and a Quart) in $uch manner as that the
+Gla$s Pipe, pa$$ing through a hole made
+purpo$ely for it in the Leaden-Cover of
+the Receiver, was for the mo$t part of it
+without the Ve$$el, which being exactly
+clo$ed, the Pump was $et awork: But at
+the very fir$t ex$uction, and before the
+Sucker was drawn to the bottom of the
+Cylinder, there flew out of the Viol a
+piece of Gla$s half as broad as the Palm
+of a Mans Hand, and it was thrown out
+with $uch violence, that hitting again$t
+<pb n=67>
+the Neighboring $ide of the Receiver, it
+not onely dafh'd it $elf to pieces, but
+crack'd the very Receiver in many places,
+with a great noi$e that much $urpri$ed all
+that were in the Room. But it $eem'd
+that in $o little a Receiver, the Air about
+the Viol being $uddenly drawn out, the
+Air Impri$on'd in the Ve$$el, having on
+it the whole pre$$ure of the Atmo$phere
+(to which by the Pipe open at both ends,
+It and the Water were expo$'d) and not
+having on the other $ide the wonted pre$-
+$ure of the Ambient Air to ballance that
+other pre$$ure, the re$i$tance of the Gla$s
+was finally $urmounted, and the Viol once
+beginning to break where it was weake$t,
+the external Air might ru$h in with vio-
+lence enough to throw the crack'd parcel
+$o forcibly again$t the Neighboring $ide
+of the Receiver, as to break that too.
+<p>And this may be pre$umed $ufficient to
+verifie what we delivered in that part of
+our Appendix to the fir$t Experiment,
+where we mention'd the almo$t equal
+pre$$ure of the Air on either $ide of a
+thin Gla$s Ve$$el, as the cau$e of its not
+being broken by the forcible Spring of
+the contain'd Air. But yet that it be not
+$u$pected that chance had an intere$t in $o
+<pb n=68>
+odde an Experiment as we have been Re-
+lating, we will adde that for farther $ati$-
+faction we reiterated it in a round Gla$$e
+containing by gue$$e about $ix ounces
+of water: this violl we put into $uch a
+$mall Receiver as was lately mention'd,
+in $uch manner as that the bottome of
+it re$ted upon the lower part of the Pneu-
+maticall Gla$$e, and the Neck came out
+through the Leaden-Cover of the $ame
+at a hole made purpo$ely for it. But be-
+ing made circum$pect by the foregoing
+mi$chance, we had put the violl into a
+Bladder, before we put it into the Re-
+ceiver to hinder this la$t named Gla$$e
+from being endanger'd by the breaking
+of the other. Then the Pneumaticall
+ve$$ell being clos'd $o that no way was
+left for the outward Air to get into it,
+but by breaking through the Viol, into
+who$e cavity it had free acce$$e by the
+mouth of it, (which was purpo$ely left
+open,) the Sucker being nimbly drawn
+down, the external Air immediatly pre$$'d
+forcibly as well upon the Leaden-Co-
+ver as the Violl; and the Cover hap-
+pening to be in one place a little narrow-
+er then the edge of the Pneumatical Gla$s,
+was depre$$'d, and thru$t into it $o vio-
+<pb n=69>
+lently by the incumbent Air, that get-
+ting a little within the tapering Lip of the
+Gla$s, it did like a kinde of Wedge, thru$t
+out that $ide where it was depre$$'d, $o as,
+though the Receiver was new, to $plit it.
+This accident being thus mention'd upon
+the by to confirm what we formerly $aid
+touching the fitne$s or unfitne$s of Gla$$es
+of $ome Figures to re$i$t the pre$$ure of
+the Atmo$phere; We will proceed to
+relate the remaining part of the Experi-
+ment, namely, That having fitted on a
+wider Cover to the $ame Receiver, and
+clo$ed both that and the crack with Ce-
+ment, we pro$ecuted the Experiment in
+the manner above related, with this $uc-
+ce$s: That upon the quick depre$$ing of
+the Sucker, the external Air bur$t the
+Body of the Viol in above a hundred pie-
+ces, many of them exceeding $mall, and
+that with $uch violence that we found a
+wide rent, be$ides many holes, made in
+the Bladder it $elf.
+<p>And to evince that the$e <I>Ph&aelig;nomena</I>
+were the effects of a limited and even
+moderate force, and not of $uch an ab-
+horrency of a <I>Vacuum</I> as that to avoid it,
+many have been plea$ed to think that Na-
+ture mu$t, upon occa$ion, exerci$e an al-
+<pb n=70>
+mo$t boundle$s power; we afterwards pur-
+po$ely try'd this Experiment with $everal
+Gla$$es $omewhat thicker then tho$e Vi-
+ols, and found the event to verifie our con-
+jecture, that it would not $ucceed: for
+the Gla$$es were taken out as intire as they
+were put in.
+<p>And here, My Lord, I hold it not un-
+fit, upon occa$ion of the mention that
+has been made of our having employ'd
+$mall Receivers, and one of them, not-
+with$tanding its being crack'd, to annex
+the$e two Adverti$ements.
+<p>Fir$t then, be$ides the great Pneuma-
+tical Gla$s $o often mention'd, and the
+proportionate Stop-cock, we thought fit
+to provide our $elves of $ome $mall Recei-
+vers blown of Cry$talline Gla$s, of $eve-
+rall Shapes, and furni$hed with $maller
+Stop-cocks purpo$ely made; and this we
+did upon hopes that when we had $ur-
+mounted the difficulties to be met with in
+Cementing the Gla$$es to the Stop-
+cocks, and the Pneumatical Ve$$els to the
+Pump $o exqui$itely as is requi$ite for our
+purpo$e, we $hould from the $malne$s of
+our Receivers receive a four-fold Advan-
+tage. The fir$t, that by rea$on of the
+$lenderne$s of the Ve$$els, and their be-
+<pb n=71>
+ing made of much purer and clearer me-
+tall, as the Gla$s-men $peak, then the
+great Receiver, we might have a more
+perfect view of every thing happening
+within them. The next, that $uch $mall
+Ve$$els might be empty'd with le$s la-
+bour and in much le$$e time. The third,
+that this nimble ex$uction of the ambient
+Air would make many changes in the
+Bodies $hut up in the$e gla$$es more $ud-
+den and con$picuous then otherwi$e they
+would prove. And the la$t, that we $hould
+be able to draw and keep out the Air much
+more perfectly from $uch $mall Ve$$els
+then from our large Receiver. But though
+we were not much di$-appointed in the
+expectation of the three fir$t advantages,
+yet we were in our hopes of the fourth.
+For be$ides the great difficulty we found
+in fitting together the Gla$$es, the Stop-
+cocks and the Covers; be$ides this I $ay,
+we found our $elves $eldom able to draw,
+and keep out the Air $o far as to make the
+remaining Air in the$e Receivers weaker
+then the remaining Air in our great Recei-
+ver. For though $ometimes the Leaks
+of $ome of the$e little Receivers may be
+much either fewer or $maller then tho$e
+of the larger Ve$$el; yet a little Air get-
+<pb n=72>
+ting into one of the$e, wherein it had but
+little room to expand and di$play it $elf,
+might pre$s as much upon all parts of the
+internal $urface of the Ve$$el, and upon
+the included Bodies, as a greater quan-
+tity of Air in a Ve$$el in who$e capacity
+it might finde more room to expand it
+$elf.
+<p>The other thing that we were to ad-
+verti$e, is, That 'tis not every $mall crack
+that can make $uch a Receiver as is of a
+roundi$h Figure altogether u$ele$s to our
+Experiment, in regard that upon the ex-
+$uction of the internal Air, the ambient
+Air on all $ides pre$$ing the Gla$s inwards
+or towards the middle, does con$equent-
+ly thru$t the Lips of the crack clo$er, and
+$o rather clo$e then increa$e it.
+<p>This I mention partly becau$e Recei-
+vers fit for our turn are more ea$ily
+crack'd then procur'd, and therefore ought
+not to be unnece$$arily thrown away as
+un$erviceable: And partly becau$e I think
+it becomes one that profe$$es him$elf a
+faithful Relator of Experiments, not to
+conceal from Your Lord$hip, that after a
+few of the foregoing Experiments were
+made, there happen'd in the great Recei-
+ver a crack of about a Span long, begin-
+<pb n=73>
+ning at the upper Orifice, and occa$ion'd,
+as it $eem'd, by the exce$$ive heat of too
+large an Iron that was employ'd to melt
+the Cement about that Orifice. But ha-
+ving laid upon this crack a broad Plai$ter,
+which in one of our E$$ays written $ome
+years $ince to your ingenious and hopeful
+Cou$in <I>Fones,</I> we extoll for the mending
+of crack'd Receivers, and other Chymi-
+cal Gla$$es; and having afterwards thick-
+ly over-laid this Plai$ter with Diachylon,
+we neither could then, nor can yet per-
+ceive that the Ve$$el leaks $en$ibly at that
+crack.
+<p>The Plai$ter was made of good quick
+Lime finely poudred, and nimbly ground
+with a Pe$tle in a Morter, with a quantity
+(I know not how much preci$ely, not ha-
+ving tho$e E$$ays in this place) of $cra-
+pings of Chee$e and a little fair Water,
+no more then is ju$t nece$$ary to bring the
+mixture to a $omewhat $oft Pa$te, which
+when the Ingredients are exqui$itely in-
+corporated, will have a $trong and
+$tincking $mell: Then it mu$t be im-
+mediately $pread upon a Linnen Cloath
+three or four fingers breadth, and pre$ently
+apply'd, le$t it begin to harden. But if
+Your Lord$hip had $een how we mended
+<pb n=74>
+with it Receivers even for the mo$t $ub-
+tle Chymical Spirits, You would $carce
+wonder at the $ervice it has done in our
+Pneumatical Gla$s.
+<p>WE took a Tallow-Candle of $uch
+<MARG><I>Experi-
+ment</I> 10.</MARG>
+a $ize that eight of them make
+about a pound, and having in a very com-
+modious Candle$tick let it down into the
+Receiver, and $o $u$pended it that the
+Flame burnt almo$t in the middle of the
+Ve$$el, we did in $ome two minutes ex-
+actly clo$e it up: and, upon Pumping ve-
+ry nimbly, we found that within little
+more then half a minute after the Flame
+went out, though the Snuff had been
+purpo$ely left of that length we judged
+the mo$t convenient for the la$ting of
+the Flame.
+<p>But the $econd time having put in the
+$ame Candle into the Receiver, (after it
+had by the bla$ts of a pair of Bellows
+been freed from Fumes) the Flame la$ted
+about two minutes from the time the
+Pumper began to draw out the Air; up-
+on the fir$t ex$uction whereof, the Flame
+$eem'd to contract it $elf in all its Dimen-
+$ions. And the$e things were further ob-
+<pb n=75>
+$ervable, that after the two or three fir$t
+ex$uctions of the Air, the Flame (except
+at the very top) appear'd exceeding blew,
+and that the Flame $till receded more and
+more from the Tallow, till at length it
+appear'd to po$$e$s onely the very top of
+the Week, and there it went out.
+<p>The $ame Candle being lighted again
+was $hut into the Receiver, to try how it
+would la$t there without drawing forth
+the Air, and we found that it la$ted much
+longer then formerly; and before it went
+out receded from the Tallow towards the
+the top of the Week, but not near $o
+much as in the former Experiment.
+<p>And having an intention to ob$erve par-
+ticularly what the motion of the $moak
+would be in the$e Experiments: We
+took notice that when the Air was not
+drawn out, there did upon the extinction
+of the Flame a con$iderable part of the
+Week remain kindled, which (probably
+by rea$on of the Circulation of the Air
+in the Ve$$el, occa$ion'd by the heat) e-
+mitted a Steam, which a$cended $wiftly
+and directly upwards in a $lender and unin-
+terrupted Cylinder of $moke, till it came
+to the top, whence it manife$tly recoyl'd
+by the $ides to the lower part of the Ve$-
+<pb n=76>
+$el. Whereas when the Flame went out
+upon the ex$uction of the Air one time
+(when the Flame retir'd very lea$urely
+to the top) we perceived it not to be fol-
+low'd by any $moke at all. And at an
+other time the upper part of the Week
+remaining kindled after the extinction
+of the Flame, the $lender $team of Fumes
+that did ari$e a$cended but a very little
+way, and then after $ome uncertain mo-
+tions this and that way, did, for the mo$t
+part, $oon fall downwards.
+<p>Being de$irous al$o to try whether
+there would be any difference as well in
+our Receiver as there is wont to be el$e-
+where betwixt Candles made of Wax and
+tho$e made of Tallow, as to their dura-
+tion; we took $lender Tapers of white
+Wax, (commonly called Virgins Wax)
+that being found to burn with much le$s
+$moke then common yellow Wax: Six
+of the$e of like bigne$s, and each of them
+of about the thickne$s of a Swans Quill,
+we pre$$'d together into one Candle: And
+having lighted all the Weeks, we let in
+the above-mention'd Wax into the Re-
+ceiver, and made what ha$te we could to
+clo$e it up with Cement. But though in
+the mean while we left open the Valve
+<pb n=77>
+of the Cylinder, the hole of the Stop-
+cock and that in the Cover of the Re-
+ceiver, that $ome Air might get in to
+cheri$h the Flame and the $moke might
+have a vent; Yet for $o great a Flame
+the Air $ufficed not $o much as till the
+Cover could be perfectly luted on: So
+that before we were quite ready to imploy
+the Pump, the Candle was extingui$hed.
+Wherefore we took but one of the a-
+bove mention'd Tapers, and having
+lighted it, clo$'d it up in the Receiver, to
+try how long a $mall Flame with a pro-
+portionable $moke would continue in
+$uch a quantity of Air: But we found
+upon two $everal tryals, that from the
+beginning of pumping, the Flame went
+out in about a minute of an hour. It
+appear'd indeed to us that the $winging
+of the Wier to and fro (in the Engine
+$haken by pumping) ha$ten'd the vani$h-
+ing of the Flame, which $eem'd by that
+motion to be ca$t $ometimes on one $ide
+of the Week and $ometimes on the o-
+ther; But though once we purpo$ely
+refrain'd pumping after a very few ex-
+$uctions of the Air, that the Flame might
+not be agitated, yet it la$ted not much
+longer then the newly mention'd time.
+<pb n=78>
+And la$tly, clo$ing up the $ame Taper,
+lighted again, to di$cover how long it
+would la$t without drawing out of the
+Air, we found that it burn'd for a while
+vividly enough, but afterwards began to
+be le$$en'd more and more in all its Di-
+men$ions. And we ob$erv'd that the
+Flame did not, as before, retire it $elf by
+little and little towards the top, but to-
+wards the bottom of the Week (from
+which yet it did a little withdraw upwards
+ju$t before it went out) $o that the upper
+part of the Week appear'd for a pretty
+while manife$tly above the top of the
+Flame, which having la$ted about five
+minutes, was $ucceeded by a directly a$-
+cending $tream of Smoak.
+<p>THere was taken a Wier, which being
+<MARG><I>Experi-
+ment</I> 11.</MARG>
+bent almo$t in the form of a Screw,
+con$tituted $uch an In$trument to contein
+Coals and leave them every way acce$$i-
+ble to the Air, as the tenth Figure de-
+clares; the breadth of this Ve$$el was no
+le$s then that it might with ea$e be con-
+vey'd into the Receiver: And having filld
+it to the height of about five Inches with
+throughly kindled Wood-coals, we let
+<pb n=79>
+it down into the Gla$s; and $peedily clo-
+$ing it, we cau$'d the Pumper to ply
+his work, and ob$erv'd that upon the ve-
+ry fir$t ex$uction of the Air (though per-
+haps not becau$e of that onely) the Fire
+in the Coals began to grow very dim, and
+though the agitation of the Ve$$el did
+make them $wing up and down (which in
+the free Air would have retarded the ex-
+tinction of the Fire) yet when we could
+no longer di$cern any redne$s at all in any
+of them; ca$ting our eyes upon a Minute-
+Watch we kept by us on this occa$ion, we
+found that from the beginning of the
+Pumping (which might be about two mi-
+nutes after the Coals had been put in
+glowing) to the total di$-appearing of
+the Fire, there had pa$$ed but three mi-
+nutes.
+<p>Whereupon, to try the Experiment a
+little further, we pre$ently took out the
+Coals, in which it $eems there had re-
+mained $ome little parcels of Fire, rather
+cover'd then totally quench'd: For in the
+open Air the Coals began to be re-kind-
+led in $everal places, wherefore having by
+$winging them about in the Wier,
+throughly lighted them the $econd time,
+welet them down again into the Receiver,
+<pb n=80>
+and clo$'d it $peedily as before; and then
+waiting till the Fire $eem'd totally ex-
+tinct without medling with the Pump, we
+found that from the time the Ve$$el was
+clo$'d till that no Fire at all could be per-
+ceiv'd there had pa$$ed about four mi-
+nutes: Whereby it $eem'd to appear that
+the drawing away of the ambient Air
+made the Fire go out $ooner then other-
+wi$e it would have done; though that part
+of the Air that we drew out left the more
+room for the $tifling $teams of the Coals
+to be received into.
+<p>La$tly, Having taken out the Wier
+and put other Coals into it, we did, in the
+$ame Room where the Engine $tood, let it
+hang quietly by a $tring in the open Air,
+to try how long the Fire would la$t with-
+out agitation when no Air was kept from
+it. And we found that the Fire began to
+go out fir$t at the top and out-$ides of the
+Coals; but inwards and near the bottom
+the Fire continu'd vi$ible for above half
+an hour, a great part of the Coals, e$pe-
+cially tho$e next the bottom, being burnt
+to a$hes before the Fire went out.
+<p>We cau$'d likewi$e a piece of Iron to
+be forg'd, of the bigne$s of a middle $iz'd
+Char-coal, and having made it red hot
+<pb n=81>
+throughout; we cau$'d it in the lately
+mention'd Wier, to be $peedily convey'd
+and $hut up into the Receiver, being de-
+$irous to try what would become of a
+glowing Body, by rea$on of its texture
+more vehemently hot then a burning
+Coal of the $ame bigne$s, &amp; yet unlike to
+$end forth $uch copious &amp; $tifling Fumes:
+But we could not ob$erve any manife$t
+change upon the ex$uction of the Air.
+The Iron began indeed to lo$e its Fiery
+redne$s at the top, but that $eem'd to be
+becau$e it was it the upper end $omewhat
+more $lender then at the lower: The red-
+ne$s, though it were in the day time, con-
+tinued vi$ible about four minutes; and
+then, before it did quite di$-appear, we
+turn'd the Key of the Stop-cock but
+could not di$cern any change of the Iron
+upon the ru$hing in of the Air. Yet $ome
+little remainders of Wax that $tuck to
+the Wier, and were turn'd into Fumes by
+the heat of the neighboring Iron, $eem'd
+to afford a more plentiful, or at lea$t a
+much more free expanded $moke when
+the Air was $uck'd out, then afterwards;
+though allowance was made for the de-
+crea$ing heat of the Iron. And la$tly,
+notwith$tanding a con$iderable ex$uction
+<pb n=82>
+of the ambient Air, though not by far $o
+great a one as might have been made by
+the Engine; and notwith$tanding the in-
+con$iderable di$$ipation of the parts of the
+Iron, the $urrounding $ides of the Recei-
+ver were $en$ibly, and almo$t offen$ively
+heated by it; in$omuch that a pretty while
+after the Iron was taken out, the $ides of
+the Gla$s manife$tly retain'd a warmth:
+which would not be unfit to be con$ider'd
+by a Per$on at more lea$ure then I am
+now.
+<p>BEing willing to try after this $ome-
+<MARG><I>Experi-
+ment</I> 12.</MARG>
+thing that would not cheri$h much
+Fire at once, and would keep Fire much
+longer then a Coal. We took a piece of
+Match, $uch as Souldiers u$e, of the thick-
+ne$s of a Mans little Finger, or $omewhat
+thicker; and this being well lighted at
+one end, was by a $tring $u$pended with
+that end downwards in the cavity of the
+Receiver which was immediately clo$'d:
+And yet by that time it could well be $o,
+the copious Fumes of the Match had neer
+fill'd and darken'd the Receiver. Where-
+fore, le$t the Ve$$el $hould be endanger'd,
+the Pump was nimbly ply'd, and a great
+<pb n=83>
+deal of Air and Smoke mixt together was
+drawn out, whereby the Receiver grow-
+ing more clear, we could di$cern the Fire
+in the Match to burn more and more lan-
+guidly: And notwith$tanding that by the
+diligence u$'d in Pumping, it $eem'd to
+have room enough allow'd it to throw
+out Fumes; yet after no long time it
+cea$'d from being di$cernable either by its
+Light or its Smoke. And though by
+that we were invited to $uppo$e it quite
+extingui$hed, yet we continu'd pumping
+a while, in pro$ecution of another Expe-
+riment we were trying at the $ame time:
+And this we did the more willingly be-
+cau$e of a $u$picion the Experiment a-
+bout the Coals might ea$ily $ugge$t, and
+which the event declar'd not to have been
+altogether groundle$s. For upon the
+Admi$$ion of the external Air, the Fire,
+that $eem'd to have gone out a pretty
+while before, did pre$ently revive; and
+being as it were refre$h d by the new Air,
+and blown by the Wind made by that
+Air in ru$hing in, it began again to $hine
+and di$$ipate the neighboring Fuel into
+Smoke as formerly.
+<pb n=84>
+<p>A While after we let down into
+<MARG><I>Experi-
+ment</I> 13.</MARG>
+the Receiver together with a ligh-
+ted piece of Match, a great Bladder well
+tyed at the Neck, but very lank, as not
+containing actually much (if any thing) a-
+bove a Pint of Air, but being capable of
+containing ten or twelve times as much.
+<p>Our $cope in this Experiment was
+partly to try whether or no the $moke of
+the Match, repleni$hing the Receiver,
+would be able to hinder the Dilatation of
+the inward Air, upon the ex$uction of the
+Ambient. And partly to di$cover whe-
+ther the extinction of the Fire in the
+Match did proceed from want of Air, or
+barely from the pre$$ure of its own
+Fumes, which for want of room to ex-
+pand them$elves in, might be $uppo$'d
+to Recoyl upon the Fire, and $o to
+$tifle it.
+<p>The event of our tryal was, That
+at the beginning of our Pumping the
+Match appear'd well lighted, though
+it had almo$t fill'd the Receiver with
+its plentiful Fumes: But by degrees it
+burnt more and more dimly, notwith-
+$tanding that by the nimble drawing
+<pb n=85>
+out the Air and Smoke, the Ve$$el
+were made le$s opacous, and le$s full of
+compre$$ing matter; as appeard by this,
+That the longer we pump'd, the le$$er
+Air and Smoke came out of the Cylin-
+der at the opening the Valve, and con$e-
+quently the le$s came into it before; yet
+the Fire in the Match went but $lowly
+out. And when afterwards, to $atisfie
+our $elves of its expiration, we had dar-
+ken'd the Room, and in vain endeavored
+to di$cover any $park of Fire, as we could
+not for $ome time before by the help of
+Candles di$cern the lea$t ri$ing of Smoke,
+we yet continued pumping $ix or $even
+times; and after all that letting in the
+Air, the $eemingly dead Fire quickly
+revived, and manife$ted its recovery by
+Light and $tore of Smoke, with the
+latter of which it quickly began to re-
+pleni$h the Receiver. Then we fell
+to pumping afre$h, and continued that
+labour $o long till the re-kindled
+Match went out again: and thinking
+it then fit not to cea$e from Pum-
+ping $o $oon as before, we found that
+in le$s then half a quarter of an hour the
+Fire was got out for good and all,
+<pb n=86>
+and pa$t the po$$ibility of being recover'd
+by the re-admitted Air.
+<p>Some Circum$tances, be$ides tho$e al-
+ready mention'd, occurr'd in the making
+of the Experiment, of which the$e are
+the principal.
+<p>Fir$t, when the Receiver was full of
+Smoke, if the Cylinder were emptied,
+immediately upon the turning of the
+Stop-cock, the Receiver would appear
+manife$tly darken'd to his eye that look'd
+upon the light through it: and this dark-
+ne$s was much le$s when the Receiver was
+much le$s fill'd with Fumes: It was al$o
+in$tantaneous, and $eem'd to proceed from
+a $udden change of place and $cituation
+in the exhalations, upon the vent $ud-
+denly afforded them and the Air they
+were mixt with, out of the Receiver into
+the Cylinder.
+<p>The next thing we ob$erv'd was, a kinde
+of <I>Halo</I> that appear'd a good while about
+the Fire, and $eem'd to be produced by
+the $urrounding Exhalations.
+<p>And la$tly, it is remarkable, That even
+when the Fumes $eemed mo$t to reple-
+ni$h the Receiver, they did not $en$ibly
+hinder the Air included in the Bladder
+from dilating it $elf after the $ame manner
+<pb n=87>
+(for ought we could di$cern) as it would
+have otherwi$e done: So that before the
+Fire or the Match was quite extinct, the
+Bladder appear'd $well'd at lea$t to $ix or
+$even times its former capacity.
+<p>Since the writing of the$e la$t Lines,
+we took a $mall Receiver, capable of
+containing (by gue$s) about a pound and
+a half of Water; and in the mid$t of it
+we $u$pended a lighted Match, but though
+within one minute of an hour (or there-
+abouts) from the putting in of the Match,
+we had cemented on the Cover, yet we
+could not make $uch ha$te, but that before
+we began to pump, the Smoke had $o
+fill'd that $mall Receiver, as for ought we
+di$cern'd, to choke the Fire. And having
+again and again reiterated the Experi-
+ment, it $eem'd $till as at fir$t, that we
+could not clo$e up the Ve$$el and pump
+out all the Fumes time enough to re$cue
+the Fire from Extinction; whereupon we
+made u$e of this Expedient. A$$oon as
+we had pump'd once or twice, we $udden-
+ly turn'd the Key, and thereby gave acce$s
+to the excluded Air, which ru$hing vio-
+lently in, as if it had been forced thorow
+a pair of Bellows, did both drive away
+the a$hes, fill the Gla$s with fre$h Air, and
+<pb n=88>
+by blowing the almo$t extingui$h'd Fire,
+re-kindl'd it, as appear'd by the Matches
+beginning again to $moke, which before it
+had cea$'d to do; we having by this
+means obtain'd a lighted Match in the
+Receiver, without being reduc'd to $pend
+time to clo$e it up, commanded the Air
+to be immediatly pump'd out, and found
+that upon the ex$uction of it, the Match
+quickly left $mokeing, as it $eem'd, by
+rea$on of the ab$ence of the Air; and
+yet if $ome urgent occa$ions had not hin-
+der'd us, we would for greater $ecurity
+have try'd, whether or no the Match re-
+kindled as formerly, would $moke much
+longer, in ca$e of no ex$uction of the am-
+bient Air.
+<p>TO try diver$e things at once,
+<MARG><I>Experi-
+ment</I> 14.</MARG>
+and particularly whether Fire,
+though we found it would not long la$t,
+might not yet be produced in our eva-
+cuated Receiver: We took a Pi$tol of
+about a Foot in length, and having
+firmly tyed it to a $tick almo$t as long as
+the Cavity of the Receiver, we very
+carefully prim'd it with well dry'd Gun-
+powder, and then cocking it, we ty'd to
+<pb n=89>
+the Tricker one end of a $tring, who$e
+other end was fa$ten'd to the Key former-
+ly mention'd to belong to the Cover of
+our Receiver. This done, we convey'd
+the Pi$tol, together with the annexed
+Staff, into the Ve$$el: which being clo$'d
+up, and empty'd after the u$ual man-
+ner, we began to turn the Key in the
+Cover; and thereby $hortning the $tring
+that reach'd from it to the Pi$tol, we
+pull'd a$ide the Tricker, and ob$erv'd,
+that according to our expectation the
+force of the Spring of the Lock was
+not $en$ibly abated by the ab$ence of
+the Air. (from who$e <I>impetus</I> yet $ome
+Modern Naturali$ts would derive the
+cau$e of the motion of Re$titution in
+$olid Bodies) For the Cock falling
+with its wonted violence upon the Steel,
+$truck out of it as many and as con$pi-
+cuous parts of Fire, as, for ought we
+could perceive, it would have done in
+the open Air. Repeating this Experi-
+ment divers times, we al$o ob$erved
+whether or no there would appear
+any con$iderable Diver$ity in the
+Motion of the $hining Sparks in a
+place where the remaining Aire was
+$o much rarified, but could not perceive
+<pb n=100>
+but that they moved $ome of them up-
+wards, as well as $ome of them down-
+wards, and $ome of them $ide-ways, as
+they are wont to do, when upon $uch col-
+li$ions they fly out in the open Air.
+<p>We likewi$e cau$'d a piece of Steel to
+be made of the form and bigne$s of the
+Flint, in who$e place we put it, and then
+the Pi$tol being cock'd and conveyed in-
+to the Receiver, the Trigger was pull'd
+after the Air was drawn out: And though
+the place were purpo$ely $omewhat dar-
+ken'd, yet there appear'd not upon the
+$triking of the two Steels again$t each o-
+ther the lea$t $park of Fire: Nor did we
+expect any (having before in vain attem-
+pted to $trike Fire this way in the open
+Air) though we thought fit to make the
+Experiment to undeceive tho$e who fan-
+cy in rarified Air, I know not what $trange
+di$po$ition, to take Fire upon a much
+$lighter occa$ion then this Experiment
+afforded. We have indeed found, that
+by the dextrous Colli$ion of two har-
+den'd pieces of Steel, $tore of $parks
+may be $truck out: But that was done with
+$uch vehement percu$$ion of the edges of
+the two Steels, as could not well be com-
+pa$$'d in our Receiver.
+<pb n=101>
+<p>But the chief thing we de$ign'd to do
+with our Pi$tol, was, To ob$erve whe-
+ther Gun-powder would take Fire in our
+empty'd and clo$ely $top'd Gla$s? Whe-
+ther the expan$ion of the Flame would be
+con$iderably varied by the ab$ence of $o
+much of the ambient Air as was drawn
+out of the Receiver? and whether the
+Flame would diffu$e it $elf upward, as it is
+wont, notwith$tanding its not having a-
+bout it the u$ual proportion of Air to
+force it up? And though mo$t of our at-
+tempts to fire the Gun-powder in the
+Pan of the Pi$tol $ucceeded not, becau$e
+we were fain to let it hang almo$t perpen-
+dicular in the Receiver; whereby the
+Powder was $haken down before the
+$parks could reach it: yet once the Ex-
+periment $ucceeded, and the kindled
+Powder $eem'd to make a more expanded
+Flame then it would have done in the
+open Air, but mounted upwards accord-
+ing to its wont, whether by rea$on of that
+little portion of Air, which in $pight of
+our pumping remained in the Receiver, or
+for any other cau$e, we have not now the
+lei$ure to con$ider. But we mu$t not for-
+get, that upon the extinction of the Flame
+the Receiver appear'd darken'd with
+<pb n=102>
+$moke, which $eem'd to move freely up
+and down, and upon the letting in the Air
+at the Stop-cock began to circulate much
+fa$ter then before. We wonld have made
+more ob$ervations concerning this Flame,
+but that of two or three attempts we
+afterwards made to repeat the kindling of
+Powder, not any one $ucceeded; and
+we have not the lea$ure to dwell long up-
+on one kinde of Tryals.
+<p>TO the$e Experiments concerning Fire
+<MARG><I>Experi-
+ment</I> 15.</MARG>
+we added another, which, though it $uc-
+ceded not, may perhaps without imper-
+tinency be recorded: partly becau$e that
+(as we have in another Treati$e amply de-
+clar'd) it is u$efull to recite what Experi-
+ments mi$carry as well as what $ucceed.
+And partly al$o becau$e it is very po$$ible
+that what we endeavored in vaine, may be
+performed by Your Lord$hip, or $ome
+other <I>Virtuo$o</I> that $hall have $lancker
+Ve$$ells then we had, and more Sunny
+dayes then the pre$ent Winter allows
+us.
+<p>We convey'd then into one of our $mall
+Receivers a piece of matter combu$tible,
+dry and black (experience declaring things
+<pb n=103>
+of that colour to be mo$t ea$ily kindled)
+&amp; carefully clo$ing the Ve$$el we brought
+it to a Window at which the Sun, not very
+faire from the Meridian, $hone in very free-
+ly: then drawing out the Aire with $peed
+united the Sun-beames with a burning
+Gla$s upon the combu$tible matter which
+began immediatly to $end forth a Smoke
+that quickly darkned the Receiver, but
+notwith$tanding all our care and diligence
+the externall Aire got in $o fa$t that after
+diver$e tryals we were fayne to leave off
+the Experiment in that Gla$$e and induc'd
+to make tryall of it in our great Re-
+ceiver.
+<p>Haveing then after $ome difficulty
+lodg'd the combu$tible matter in the ca-
+vity of this Ve$$ell in $uch manner as that
+it was almo$t contiguous to that $ide
+thereof that was next the Sun, we did en-
+deavor with a pretty large burning Gla$s
+to kindle it, but found, as we fear'd,
+That by rea$on of the thickne$s of the
+Gla$s, (which was al$o of a le$s pure and
+le$s Diaphanous matter then the o-
+ther) the Sun-beams thrown in by the
+burning Gla$s, were in their pa$$age
+$o Di$located and Scattered (not now to
+mention tho$e many that being reflected,
+<pb n=104>
+I could not pierce into the cavity of the
+Receiver) that we could not po$$ibly u-
+nite enough of them to kindle the matter,
+nor $o much as to make it $en$ibly $moke.
+Yet we hope that the $eeing whether Bo-
+dies (other then Gun-powder) may be
+kindled, and what would happen to them
+when $et on fire, in a place in great mea-
+$ure devoid of Air, may prove $o Lucife-
+rous an Experiment, that when the Sea-
+$on is more favorable we $hall, God per-
+mitting, make further tryal of it, and ac-
+quaint Your Lord$hip with the Event, if
+it prove pro$perous. In the mean time
+we $hall pa$s on to other Experiments,
+a$$oon as we have adverti$'d Your Lord-
+$hip that we have forborn to make $uch
+Reflections upon the $everal Experiments
+we have $et down concerning Fire, as the
+matter would have ea$ily enough afford-
+ed, and Your Lord$hip may perhaps have
+expected. But I made the le$s $cruple to
+forbear the annexing of Speculations to
+the$e Recitals, becau$e <I>Carneades</I> &amp; <I>Eleu-
+therius</I> have in $ome Dialogues concern-
+ing Heat and Flame, which were la$t year
+$een by $ome Friends, and may be, when
+you plea$e, commanded by You, men-
+<pb n=105>
+tion'd divers of my Thoughts and Expe-
+riments concerning Fire.
+<p>WE de$igned to try whether or no
+<MARG><I>Experi-
+ment</I> 16</MARG>
+divers Magnetical Experiments
+would exhibit any unu$ual <I>Ph&aelig;nomena,</I>
+being made in our Evacuated Receiver
+in$tead of the open Air: But for want of
+lei$ure and conveniency to pro$ecute $uch
+Tryals, we were induced to re$erve the
+re$t for an other time, and to content our
+$elves with making that which follows.
+We convey'd into the Receiver a little
+Pede$tal of Wood, in the mid$t of which
+was perpendicularly erected a $lender
+Iron, upon who$e $harp point an excited
+Needle of Steel purpo$ely made, and of
+about five Inches long, was $o placed
+that hanging in an <I>&AElig;quilibrium</I> it could
+move freely towards either hand. Then
+the Air being after the u$ual manner
+pumped out, we apply'd a Load-$tone
+moderately vigorous to the out-$ide of
+of the Gla$s, and found that it Attracted
+or Repell'd the ends of the Needle, accor-
+ding to the Laws Magnetical, without
+any remarkable difference from what the
+$ame Load-$tone would have done had
+<pb n=106>
+none of the Air been drawn away from a-
+bout the Needle, which when the Load-
+$tone was removed, after $ome tremu-
+lous Vibrations to and fro, re$ted in a po-
+$ition wherein it look'd North and
+South.
+<p>PRoceed we now to the mention of
+<MARG><I>Experi-
+ment</I> 17.</MARG>
+that Experiment, whereof the $ati$-
+factory tryal was the principal Fruit I
+promi$'d my $elf from our Engine. It
+being then $ufficiently known, that, in
+the Experiment <I>De Vacuo,</I> the Quick-
+$ilver in the Tube is wont to remain ele-
+vated, above the $urface of that whereon
+it leans, about 27 digits: I con$idered,
+that, if the true and onely rea$on why the
+Quick-$ilver falls no lower, be, that at
+that Altitude, the Mercurial Cylinder in
+the Tube, is an <I>&AElig;quilibrium</I> with the
+Cylinder of Air, $uppo$'d to reach from
+the adjacent Mercury to the top of the
+Atmo$phere: If this Experiment could
+be try'd out of the Atmo$phere, the
+Quick-$ilver in the Tube would fall
+down to a levell with that in the Ve$$el,
+$ince then there would be no pre$$ure up-
+on the Subjacent, to re$i$t the weight of
+<pb n=107>
+the Incumbent Mercury. Whence I in-
+ferr'd (as ea$ily I might) that, if the Ex-
+periment could be try'd in our Engine, the
+Quick-$ilver would $ub$ide below 27 Di-
+gits, in proportion to the ex$uction of
+Air, that $hould be made out of the Re-
+ceiver. For, as when the Air is $hut in-
+to the Receiver, it does (according to
+what hath above been taught) continue
+there as $trongly compre$$'d, as it did
+whil'$t all the incumbent Cylinder of the
+Atmo$phere lean'd immediatly upon it;
+becau$e the Gla$s, wherein it is pent up,
+hinders it to deliver it $elf, by an expan$i-
+on of its parts, from the pre$$ure where-
+with it was $hut up. So, if we could per-
+fectly draw the Air out of the Receiver,
+it would conduce as well to our purpo$e,
+as if we were allow'd to try the Experi-
+ment beyond the Atmo$phere.
+<p>Wherefore (after having $urmounted
+$ome little difficulties which occurr'd at
+the beginning) the Experiment was made
+after this manner. We took a $lender and
+very curiou$ly blown Cylinder of Gla$s,
+of near three Foot in length, and who$e
+bore had in Diameter a quarter of an Inch,
+wanting a hairs breadth: This Pipe being
+Hermetically $eal'd at one end, was, at
+<pb n=108>
+the other, fill'd with Quick-$ilver, care
+being taken in the filling, that as few
+bubles as was po$$ible $hould be left in the
+Mercury: Then the Tube being $topt
+with the Finger and inverted, was open'd,
+according to the manner of the Experi-
+ment, into a $omewhat long and $lender
+Cylindrical Box (in$tead of which we now
+are wont to u$e a Gla$s of the $ame form)
+half fill'd with Quick-$ilver: And $o, the
+liquid metal being $uffered to $ub$ide, and
+a piece of Paper being pa$ted on levell
+with its upper $urface, the Box and Tube
+and all were by $trings carefully let down
+into the Receiver, and then, by means of
+the hole formerly mention'd to be left in
+the Cover, the $aid Cover was $lip't along
+as much of the Tube as reach'd above the
+top of the Receiver; And the Interval,
+left betwixt the $ides of the Hole and
+tho$e of the Tube, was very exqui$itely
+fill'd up with melted (but not over hot)
+Diachylon; and the round chink, betwixt
+the Cover and the Receiver, was likewi$e
+very carefully clo$'d up: Upon which clo-
+$ure there appear'd not any change in the
+height of the Mercurial Cylinder; no
+more, then if the interpo$'d Gla$s Recei-
+ver did not hinder the immediate pre$$ure
+<pb n=109>
+of the ambient Atmo$phere upon the
+inclo$ed Air; which hereby appears to
+bear up on the Mercury, rather by virtue
+of its $pring, then of its weight: $ince its
+weight cannot be $uppo$'d to amount to
+above two or three Ounces, which is in-
+con$iderable in compari$on of $uch a Cy-
+linder of Mercury as it would keep from
+$ub$iding.
+<p>All things being thus in a readine$s, the
+Sucker was drawn down; and, immedi-
+ately upon the egre$s of a Cylinder of
+Air out of the Receiver; the Quick-$ilver
+in the Tube did, according to expectati-
+on, $ub$ide: and notice being carefully
+taken (by a mark fa$ten'd to the out$ide)
+of the place where it $topt, we cau$'d him
+that manag'd the Pump to pump again,
+and mark'd how low the Quick-$ilver fell
+at the $econd ex$uction; but continuing
+this work, we were quickly hindred from
+accurately marking the Stages made by
+the Mercury in its de$cent, becau$e it $oon
+$unk below the top of the Receiver; $o
+that we could thenceforward mark it no
+other ways then by the eye. And thus,
+continuing the labor of pumping for a-
+bout a quarter of an hour, we found our
+$elves unable to bring the Quick-$ilver in
+<pb n=110>
+the Tube totally to $ub$ide; becau$e,
+when the Receiver was con$iderably em-
+pty'd of its Air, and con$equently that
+little that remain'd grown unable to re$i$t
+the Irruption of the external, that Air
+would (in $pight of whatever we could
+do) pre$s in at $ome little Avenue or
+other; and though much could not there-
+at get in, yet a little was $ufficient to coun-
+terballance the pre$$ure of $o $mall a Cy-
+linder of Quick-$ilver, as then remain'd
+in the Tube.
+<p>Now (to $atisfie our $elves further, that
+the failing of the Quick-$ilver in the
+Tube to a determinate height, proceeds
+from the <I>&AElig;quilibrium,</I> wherein it is at
+that height with the external Air, the one
+gravitating, the other pre$$ing with equal
+force upon the $ubjacent Mercury) we Re-
+turned the Key and let in $ome new Air;
+upon which the Mercury immediatly be-
+gan to a$cend (or rather to be impell'd up-
+wards) in the Tube, and continu'd a$cend-
+ing, till having Return'd the Key it im-
+mediatly re$ted at the height which it had
+then attain'd: And $o, by Turning and
+Returning the Key, we did $everal times
+at plea$ure impel it upwards, and check its
+a$cent. And la$tly, having given a free
+<pb n=111>
+egre$s at the Stop-cock to as much of the
+external Air as would come in, the Quick-
+$ilver was impell'd up almo$t to its fir$t
+height: I $ay almo$t, becau$e it $topt
+near a quarter of an Inch beneath the Pa-
+per mark formerly mention'd; which we
+a$crib'd to this, That there was (as is u-
+$ual in this Experiment) $ome little Parti-
+cles of Air engag'd among tho$e of the
+Quick-$ilver; which Particles, upon the
+de$cent of the Quick-$ilver, did manife$t-
+ly ri$e up in Bubbles towards the top of
+the Tube, and by their pre$$ure, as well
+as by le$$ening the Cylinder by as much
+room as they formerly took up in it, hin-
+der'd the Quick-$ilver from regaining its
+fir$t height.
+<p>This Experiment was a few days after
+repeated in the pre$ence of tho$e excellent
+and de$ervedly Famous Mathematick
+Profe$$ors, Dr. <I>Wallis,</I> Dr. <I>Ward,</I> and Mr.
+<I>Wren,</I> who were plea$ed to Honor it with
+their Pre$ence: And whom I name, both
+as ju$tly counting it an Honor to be
+known to them, and as being glad of $uch
+Judicious and illu$trious Witne$$es of our
+Experiment; and 'twas by their gue$s that
+the top of the Quick-$ilver in the Tube
+was defin'd to be brought within an Inch
+<pb n=112>
+of the $urface of that in the Ve$$el.
+<p>And here, for the Illu$tration of the
+foregoing Experiment, it will not be a-
+mi$s to mention $ome other particulars
+relating to it.
+<p>Fir$t then, When we endeavor'd to
+make the Experiment with the Tube
+clo$'d at one end with <I>Diachylon</I> in$tead
+of an Hermetical Seal; we perceiv'd, that
+upon the drawing of $ome of the Air out
+of the Receiver, the Mercury did indeed
+begin to fall, but continu'd afterwards to
+$ub$ide, though we did not continue pum-
+ping. Whence it appear'd, that though
+the <I>Diachylon</I> that $topt the end of the
+Tube were $o thick and $trong, that the
+external Air could not pre$s it in (as expe-
+rience taught us that it would have done,
+if there had been but little of it) yet the
+$ubt'ler parts of it were able (though
+$lowly) to in$inuate them$elves through
+the very body of the Plai$ter, which it
+$eems was of $o clo$e a Texture, as that
+which we mention'd our $elves to have
+$ucce$sfully made u$e of in the Experi-
+ment <I>De Vacuo</I> $ome years ago. So that
+now we begin to $u$pect, that perhaps one
+Rea$on, why we cannot perfectly pump
+out the Air, may be, that when the Ve$$el
+<pb n=113>
+is almo$t empty, $ome of the $ubtler
+parts of the external Air may, by the
+pre$$ure of the Atmo$phere, be $train'd
+through the very body of the <I>Diachylon</I>
+into the Receiver. But this is onely con-
+jecture:
+<p>Another Circum$tance of our Expe-
+riment was this, That, if (when the
+Quick-$ilver in the Tube was fallen low)
+too much ingre$s were, at the hole of the
+Stop-cock, $uddenly permitted to the ex-
+ternal Air; it would ru$h in with that vio-
+lence, and bear $o forcibly upon the $ur-
+face of the $ubjacent Quick-$ilver, that
+it would impel it up into the Tube rudely
+enough to endanger the breaking of the
+Gla$s.
+<p>We formerly mention'd, that the
+Quick-$ilver did not in its de$cent fall as
+much at a time after the two or three fir$t
+ex$uctions of the Air, as at the beginning:
+For, having mark'd its $everal Stages up-
+on the Tube, we found, that at the fir$t
+$uck it de$cended an Inch and 3/8, and at the
+$econd an Inch and 1/8; and when the Ve$-
+$el was almo$t empty'd, it would $carce at
+one ex$uction be drawn down above the
+breadth of a Barly-corn. And indeed we
+found it very difficult to mea$ure in what
+<pb n=114>
+proportion the$e decrements of the Mer-
+curial Cylinder did proceed: partly be-
+cau$e (as we have already intimated) the
+Quick $ilver was $oon drawn below the
+top of the Receiver: and partly becau$e,
+upon its de$cent at each ex$uction, it
+would immediatly rea$cend a little up-
+wards; either by rea$on of the leaking of
+the Ve$$el at $ome imperceptible hole or
+other, or by rea$on of the motion of
+Re$titution in the Air, which, b<*>ng $ome-
+what compre$t by the fall as well as weight
+of the Quick $ilver, would repell it a lit-
+tle upwards, and make it vibrate a little up
+and down, before they could reduce each
+other to $uch an <I>&AElig;quilibrium</I> as both
+might re$t in. But though we could not
+hitherto make ob$ervations accurate e-
+nough concerning the mea$ures of the
+Quick-$ilver's de$cent, to reduce them in-
+to any <I>Hypothe$is,</I> yet would we not di$-
+courage any from attempting it: $ince, if it
+could be reduc'd to a certainty, tis proba-
+ble that the di$covery would not be un-
+u$eful.
+<p>And, to illu$trate this matter a little
+more, we will adde, That we made a $hift
+to try the Experiment in one of our above
+mention'd $mall Receivers, not containing
+<pb n=115>
+a Quart; but that (agreeably to what we
+formerly ob$erved) we found it as difficult
+to bring this to be quite empty as to eva-
+cuate the greater; the lea$t external Air
+that could get in (and we could not po$$i-
+bly keep it all perfectly out) $ufficing in $o
+$mall a Ve$$el to di$play a con$iderable
+pre$$ure upon the $urface of the Mercury,
+and thereby hinder that in the Tube from
+falling to a level with it. But this is remark-
+able, that having two or three times try'd
+the Experiment in that $mall Ve$$el, upon
+the very fir$t Cylinder of Air that was
+drawn out of the Receiver, the Mercury
+fell in the Tube 18 Inches and a half, and
+at another 19 Inches and a half.
+<p>But, on this occa$ion, I hold it not un-
+fit to give Your Lord$hip notice that I
+hop'd, from the de$cent of the Quick-
+$ilver in the Tube upon the fir$t $uck, to
+derive this advantage: that I $hould thence
+be enabled to give a near gue$s at the pro-
+portion of force betwixt the pre$$ure of
+the Air (according to its various $tates, as
+to Den$ity and Rarefaction) and the gra-
+vity of Quick-$ilver, then hitherto has
+been done. For in our Experiment there
+are diver$e things given, that may be
+made u$e of towards $uch a di$covery.
+<pb n=116>
+For fir$t we may know the capacity of the
+Receiver wherein the Experiment is
+made, $ince, by filling it with water, we
+may ea$ily compute how many Quarts, or
+Mea$ures of any other denomination, it
+contains of Air; which Air, when $hut
+up in the Ve$$el, may be $uppo$'d to have
+a pre$$ure equal to that of the Atmo-
+$phere; $ince it is able to keep the Quick-
+$ilver in the Tube from falling any lower
+then it did in the free and open Air. Next
+here is given us the capacity of the bra$s
+Cylinder empty'd by the drawing down
+of the Sucker (its bore and height being
+mention'd in the de$cription of our Pump)
+whereby we may come to know how
+much of the Air contain'd in the Recei-
+ver is drawn out at the fir$t $uck. And
+we may al$o ea$ily define, either in weight
+or cubick mea$ures the Cylinder of
+Quick-$ilver that an$wers to the Cy-
+linder of Air lately mention'd (that
+Mercuriall Cylinder being in our En-
+gine computable by deducting from
+the entire altitude or that Cylinder of
+Quick-$ilver, the altitude at which it re$ts
+upon the fir$t ex$uction.) But though, if
+this Experiment were very watchfully
+try'd in Ve$$els of $everal $izes, and the
+<pb n=117>
+various de$cents of the Quick-$ilver com-
+par'd among them$elves, 'tis not impro-
+bable that $ome $uch thing as we hop'd for
+may thereby be di$cover'd. Yet becau$e
+not onely the $olid contents of as much
+of the Gla$s-tube as remains within the
+concave $urface of the Receiver, and
+(which is more difficult) the varying con-
+tents of the Ve$$el containing the Mer-
+cury, and of as much of the Mercury it
+$elf as is not in the Tube, mu$t be dedu-
+cted out of the capacity of the Receiver;
+but there mu$t al$o an allowance be made
+for this, that the Cylinder that is empty'd
+by the drawing down of the Sucker, and
+comes to be fill'd upon the letting of the
+Air out of the Receiver into it, is not $o
+repleni$h'd with Air as the Receiver it $elf
+at fir$t was: becau$e there pa$$es no more
+Air out of the Receiver into the Cylin-
+der, then is requi$ite to reduce the Air in
+the cavity of the Cylinder, and in that of
+the Receiver to the $ame mea$ure of dila-
+tation: Becau$e of the$e (I $ay) and $ome
+other difficulties that require more skill in
+Mathematicks then I pretend to, and much
+more lea$ure then my pre$ent occa$ions
+would allow me, I was willing to refer the
+nicer con$ideration of this matter to $ome
+<pb n=118>
+of our Learned and Acurate Mathema-
+ticians, thinking it enough for me to have
+given the Hint already $ugge$ted.
+<p>For further confirmation of what hath
+been delivered, we likewi$e tryed the Ex-
+periment in a Tube of le$s then two foot
+long: and, when there was $o much Air
+drawn out of the Ve$$el, that the remain-
+ing Air was not able to counterballance
+the Mercurial Cylinder, the Quick-$ilver
+in the Tube $ub$ided $o vi$ibly, that (the
+Experiment being try'd in the little Ve$-
+$el lately mention'd) at the fir$t $uck it
+fell above a $pan, and was afterwards
+drawn lower and lower for a little while;
+and the external Air being let in upon it,
+impell'd it up again almo$t to the top of
+the Tube: So little matters it how heavy
+or light the Cylinder of Quick $ilver to
+$ub$ide is, provided its gravity over-
+power the pre$$ure of as much external
+Air as bears upon the $urface of that Mer-
+cury into which it is to fall.
+<p>La$tly we al$o ob$erv'd, That if (when
+the Mercury in the Tube had been drawn
+down, and by an Ingre$s permitted to the
+external Air, impell'd up again to its for-
+mer height) there were $ome more Air
+thru$t up by the help of the Pump into
+<pb n=119>
+the Receiver, the Quick-$ilver in the Tube
+would a$cend much above the wonted
+height of 27 digits, and immediatly up-
+on the letting out of that Air would fall a-
+gain to the height it re$ted at before.
+<p>Your Lord$hip will here perhaps expect,
+that as tho$e who have treated of the <I>Tor-
+ricellian</I> Experiment, have for the mo$t
+part maintaind the Affirmative, or the Ne-
+gative of that famous Que$tion, Whether
+or no that Noble Experiment infer a <I>Va-
+cuum?</I> $o I $hould on this occa$ion inter-
+po$e my Opinion touching that Contro-
+ver$ie, or at lea$t declare whether or no, in
+our Engine, the ex$uction of the Air do
+prove the place de$erted by the Air $uck'd
+out, to be truly empty, that is, devoid of
+all Corporeal Sub$tance. But be$ides that,
+I have neither the lei$ure, nor the ability,
+to enter into a $olemn Debate of $o nice a
+Que$tion; Your Lord$hip may, if you
+think it worth the trouble, in the Dia-
+logues not long $ince referr'd to, finde the
+Difficulties on both $ides repre$ented;
+which then made me yield but a very wa-
+vering a$$ent to either of the parties con-
+tending about the Que$tion: Nor dare I
+yet take upon me to determine $o difficult
+a Controver$ie.
+<pb n=120>
+<p>For on the one $ide it appears, that not-
+with$tanding the ex$uction of the Air, our
+Receiver may not be de$titute of all Bo-
+dies, $ince any thing placed in it, may be
+$een there; which would not be, if it
+were not pervious to tho$e Beams of
+Light which rebounding from the $een
+Object to our eyes, affect us with the $en$e
+of it: And that either the$e Beams are
+Corporeal Emanations from $ome lucid
+body, or el$e at lea$t the light they convey
+doth re$ult from the brisk Motion of $ome
+$ubtle Matter, I could, if I mi$take not,
+$ufficiently manife$t out of the Dialogues
+above-mention'd, if I thought your Lord-
+$hip could $eriou$ly imagine that Light
+could be convey'd without, at lea$t, having
+(if I may $o $peak) a Body for its Ve-
+hicle.
+<p>By the $ixteenth Experiment, it al$o
+appears that the clo$ene$s of our Receiver
+hinders it not from admitting the Efflu-
+via of the Load-$tone; which makes it
+very probable that it al$o freely admits
+the Magnetical $teams of the Earth; con-
+cerning which, we have in another Trea-
+ti$e endeavour'd to manife$t that numbers
+of them do always permeate our Air.
+<p>But on the other $ide it may be $aid,
+<pb n=121>
+That as for the $ubtle Matter which makes
+the Objects enclo$ed in our evacuated Re-
+ceiver, vi$ible, and the Magnetical Efflu-
+via of the Earth that may be pre$um'd to
+pa$s thorow it, though we $hould grant
+our Ve$$el not to be quite devoyd of
+them, yet we cannot $o rea$onably affirm
+it to be repleni$h'd with them, as we may
+$uppo$e, that if they were gather'd toge-
+ther into one place without Intervals be-
+tween them, they would fill but a $mall
+part of the whole Receiver. As in the
+thirteenth Experiment, a piece of Match
+was incon$iderable for its bulk, while$t its
+parts lay clo$e together, that afterwards
+(when the Fire had $catter'd them into
+$moke) $eem'd to repleni$h all the Ve$$el.
+For (as el$ewhere our Experiments have
+demon$trated) both Light and the Efflu-
+via of the Load-$tone, may be readily ad-
+mitted into a Gla$s, Hermetically $eal'd,
+though before their Admi$$ion, as full of
+Air as hollow Bodies here below are wont
+to be, $o that upon the ex$uction of the
+Air, the large $pace de$erted by it, may
+remain empty, notwith$tanding the pre-
+tence of tho$e $ubtle Corpu$cles, by
+which Lucid and Magnetical Bodies pro-
+duce their effects.
+<pb n=122>
+<p>And as for the Allegations above
+mention'd, they $eem to prove but that
+the Receiver devoy'd of Air, <I>May</I> be re-
+pleni$h'd with $ome $uch Etherial Matter,
+as $ome Modern Naturali$ts write of; but
+not that it really <I>is</I> $o. And indeed to me
+it yet $eems, that as to tho$e $paces which
+the <I>Vacui$ts</I> would have to be empty, be-
+cau$e they are manife$tly devoid of Air;
+and all gro$$er Bodies, the <I>Pleni$ts</I> (if I
+may $o call them) do not prove that $uch
+$paces are repleni$h'd with $uch a $ubtle
+Matter as they $peak of, by any $en$ible
+effects, or operations of it (of which di-
+vers new Tryals purpo$ely made, have not
+yet $hown me any) but onely conclude
+that there mu$t be $uch a Body, becau$e
+there cannot be a Void. And the rea$on
+why there cannot be a Void, being by
+them taken, not from any Experiments,
+or <I>Ph&aelig;nomena</I> of Nature, that clearly and
+particularly prove their <I>Hypothe$is,</I> but
+from their notion of a Body, who$e Na-
+ture, according to them, con$i$ting one-
+ly in exten$ion (which indeed $eems the
+property mo$t e$$ential to, becau$e in$epa-
+rable from a Body) to $ay a $pace devoid
+of Body, is to $peak in the School-mens
+Phra$e, a Contradiction <I>in Adjecto:</I> This
+<pb n=123>
+rea$on, I $ay, being thus de$um'd, $eems
+to make the Controver$ie about a <I>Vacu-
+um,</I> rather a Metaphy$ical, then a Phy$io-
+logical Que$tion; which therefore we $hall
+here no longer debate, finding it very dif-
+ficult either to $atisfie Naturali$ts with
+this Carte$ian Notion of a Body, or to
+manife$t wherein it is erroneous, and $ub-
+$titute a better in its $tead.
+<p>But though we are unwilling to exa-
+mine any further the Inferences wont to
+be made from the <I>Torricellian</I> Experi-
+ment, yet we think it not impertinent to
+pre$ent Your Lord$hip with a couple of
+Adverti$ements concerning it.
+<p>Fir$t, then if in trying the Experiment
+here or el$ewhere, you make u$e of the
+Engli$h mea$ures that Mathematicians
+and Trade$men are here wont to imploy,
+You will, unle$s you be forewarn'd of it,
+be apt to $u$pect that tho$e that have writ-
+ten of the Experiment have been mi$ta-
+ken. For whereas men are wont gene-
+rally to talk of the Quick-$ilver's remain-
+ing $u$pended at the heighth of between
+$ix or $even and twenty Inches; we com-
+monly ob$erv'd, when divers years $ince
+we fir$t were $ollicitous about this Expe-
+riment, that the Quick-$ilver in the Tube
+<pb n=124>
+re$ted at about 29 Inches &amp; an half above
+the $urface of the Re$tagnant Quick-$ilver
+in the Ve$$el, which did at fir$t both amaze
+and perplex us, becau$e though we held it
+not improbable that the difference of the
+gro$$er Engli$h Air, and that of <I>Italy</I> and
+<I>France,</I> might keep the Quick-$ilver from
+falling quite as low in this colder, as in
+tho$e warmer Climates; yet we could
+not believe that that difference in the Air
+$hould alone be able to make $o great a one
+in the heights of the Mercurial Cylinders;
+and accordingly upon enquiry we found,
+that though the various den$ity of the
+Air be not to be over-look'd in this Ex-
+periment, yet the main Rea$on why we
+found the Cylinder of Mercury to con$i$t
+of $o many Inches, was this, That our
+Engli$h Inches are $omewhat inferior in
+length to the digits made u$e of in Fo-
+rein Parts, by the Writers of the Expe-
+riment.
+<p>The next thing I de$ire Your Lord$hip to
+take notice of, is, That the heigth of the
+Mercurial Cylinder is not wont to be fo&utilde;d
+altogether $o great as really it might
+prove, by rea$on of the negligence or in-
+cogitancy of mo$t that make the Experi-
+ment. For often times upon the opening
+<pb n=125>
+of the inverted Tube into the Ve$$ell'd
+Mercury, you may ob$erve a bubble of
+Air to a$cend from the bottom of the
+Tube through the $ub$iding Quick-$ilver
+to the top; and almo$t always you may,
+if you look narrowly, take notice of a
+multitude of $mall bubbles all along the
+in$ide of the Tube betwixt the Quick-
+$ilver &amp; the gla$s: (not now to mention the
+Particles of Air that lye conceal'd in the
+very Body of the Mercury) Many of
+which, upon the Quick-$ilvers for$aking
+the upper part of the Tube, do break in-
+to that de$erted $pace where they finde
+little or no re$i$tance to their expanding
+of them$elves. Whether this be the rea-
+$on that upon the Application of warm
+Bodies to the emptyed part of the Tube,
+the $ubjacent Mercury would be depre$$'d
+$omewhat lower, we $hall not determine;
+though it $eem very probable, e$pecially
+$ince we found that upon the application
+of Linnen cloaths dipped in Water, to
+the $ame part of the Tube, the Quick-
+$ilver would $omewhat a$cend, as if the
+cold had conden$'d the Impri$on'd Air,
+that pre$$'d upon it, into a le$$er room.
+But that the de$erted $pace is not wont to
+be totally devoid of Air, we were induc'd
+<pb n=126>
+to think by $everal Circum$tances. For
+when an eminent Mathematician, and ex-
+cellent Experimenter, had taken great
+pains and $pent much time in accuratly fil-
+ling up a Tube of Mercury, we found
+that yet there remain'd $tore of incon$pi-
+cuous bubbles, by inverting the Tube,
+letting the Quick-$ilver fall to its wonted
+heighth; and by approaching (by de-
+grees) a red hot Iron to the out-$ide of the
+Tube, over again$t the upper part of the
+Mercurial Cylinder, for hereby the little
+unheeded bubbles, being mightily expan-
+ded, a$cended in $uch numbers, and $o fa$t
+to the de$erted $pace, that the upper part
+of the Quick-$ilver $eem'd, to our wonder,
+to boyl. We further ob$erv'd, That in
+the tryals of the <I>Torricellian</I> Experiment
+we have $een made by others, and (one
+excepted) all our own, we never found that
+upon the inclining of the Tube the Quick-
+$ilver would fully reach to the very top of
+the $eal'd end: which argued, that there
+was $ome Air retreated thither that kept
+the Mercury out of the unrepleni$h'd
+$pace.
+<p>If Your Lord$hip $hould now demand
+what are the be$t expedients to hinder the
+intru$ion of the Air in this Experiment;
+<pb n=127>
+we mu$t an$wer, That of tho$e which are
+ea$ily intelligible without ocular demon-
+$tration, we can at pre$ent $ugge$t upon
+our own tryals no better then the$e. Fir$t,
+at the open end of the Tube the Gla$s
+mu$t not onely be made as even at the ed-
+ges as you can, but it is very conveni-
+ent (e$pecially if the Tube be large) that
+the bottom be every way bent inwards,
+that $o the Orifice, not much exceeding a
+quarter of an Inch in Diameter, may be
+the more ea$ily and exactly $topp'd by the
+Experimenter's finger; between which
+and the Quick-$ilver, that there may be
+no Air intercepted (as very often it hap-
+pens that there is) it is requi$ite that the
+Tube be fill'd as full as po$$ibly it can be,
+that the finger which is to $top it, pre$$ing
+upon the accumulated and protuberant
+Mercury, may rather throw down $ome,
+then not finde enough exactly to keep out
+the Air. It is al$o an u$eful and compen-
+dious way not to fill the Tube at fir$t
+quite ful of Mercury, but to leave near the
+top about a qnarter of an Inch empty; for
+if you then $top the open end with your
+finger, and invert the Tube that quarter
+of an Inch of Air will a$cend in a great
+bubble to the top, and in its pa$$age thi-
+<pb n=128>
+ther, will gather up all the little bubbles,
+and unite them with it$elf into one great
+one, $o that if by reinverting the Tube
+you let that bubble return to the open
+end of it, you will have a much clo$er Mer-
+curial Cylinder then before, and need but
+to adde a very little Quick-$ilver more to
+fill up the Tube exactly. And la$tly, as for
+tho$e le$$er and incon$picuous parcels of
+Air which cannot this way be gleaned up,
+You may endeavor before you invert the
+Tube, to free the Quick-$ilver from them
+by $haking the Tube, and gently knock-
+ing on the out-$ide of it, after every little
+parcel of Quick-$ilver which you pour in;
+and afterwards, by forcing the $mall la-
+titant bubbles of Air to di$clo$e them-
+$elves and break, by imploying a hot Iron
+in $uch manner as we lately mention'd. I
+remember that by carefully filling the
+Tube, though yet it were not quite free
+from Air, we have made the Mercurial
+Cylinder reach to 30 Inches and above an
+eighth, and this in a very $hort Tube:
+which we therefore mention, becau$e we
+have found, by experience, that in $hort
+Tubes a little Air is more prejudicial to
+the Experiment then in long ones, where
+the Air having more room to expand it
+<pb n=129>
+$elf, does le$s potently pre$s upon the $ub-
+jacent Mercury.
+<p>And $ince we are fallen upon the con$i-
+deration of the Altitude of the Mercurial
+Cylinder, I mu$t not conceal from Your
+Lord$hip an Experiment relating thereun-
+to, which perhaps will $et both You and
+many of your Friends the <I>Virtuo$i</I> a think-
+ing; and, by di$clo$ing $ome things a-
+bout the Air or Atmo$phere that have
+$carce hitherto been taken notice of, may
+afford you $ome hints conducive to a fur-
+ther di$covery of the $ubject of this E-
+pi$tle.
+<p>WE took a Gla$s Tube, which,
+<MARG><I>Experi-
+ment</I> 18.</MARG>
+though it were not much above
+three Foot long, we made choice of be-
+cau$e it was of a more then ordinarily
+even thickne$s. This we fill'd with Mer-
+cury, though not with as much care as we
+could, yet with $omewhat more then is
+wont to be u$ed in making the <I>Torricellian</I>
+Experiment. Then, having according to
+the manner inverted the Tube, and open'd
+the mouth of it beneath the $urface of
+$ome other Quick-$ilver, that in the Tube
+fell down to the wonted heigth, leaving,
+<pb n=130>
+as is u$ual, $ome little Particles of Air in
+the $pace it de$erted, as we ghe$t by ob-
+$erving, that upon the Application of hot
+Bodies to the upper part of the Tube, the
+Quick-$ilver would be a little depre$$'d.
+La$tly, having put both the Tube and the
+Ve$$el it lean'd on into a convenient
+Wooden Frame, to keep them from mi$-
+chances: we plac'd that Frame in a Win-
+dow within my Bed-chamber, that I might
+both keep the Mercury from being $tirr'd,
+and have opportunity to watch from time
+to time the <I>Ph&aelig;nomena</I> it was to exhibit.
+For the better di$covery of which, when
+the Quick-$ilver both in the Tube and
+$ubjacent Ve$$el was perfectly at re$t, we
+took notice, by a mark made on the out-
+$ide of the Gla$s, how high the included
+Liquor then reach'd.
+<p>During $everal Weeks that the Tube
+was kept in that Window (which was very
+rarely open'd) I had the opportunity to
+ob$erve, that the Quick-$ilver did $ome-
+times faintly imitate the Liquor of a
+Weather-gla$s, $ub$iding a little in warm,
+and ri$ing a little in cold Weather, which
+we a$cribed to the greater or le$$er pre$$ure
+of that little Air that remain'd at the top
+of the Tube, expanded or conden$'d by
+<pb n=131>
+the heat or cold that affected the ambient
+Air. But that which I was chiefly careful
+to ob$erve, was this, That oftentimes the
+Quick-$ilver did ri$e and fall in the Tube,
+and that very notably, without conforming
+it $elf to what is u$ual in Weather-gla$$es,
+who$e Air is at the top, nay quite contrary
+thereunto: for $ometimes I ob$erv'd it in
+very cold weather ($uch as this Winter has
+already afforded us good $tore of) to fall
+down much lower then at other times,
+when by rea$on of the ab$ence of both
+Fro$t, Snow, and $harp Winds, the Air was
+comparatively much warmer. And I fur-
+ther ob$erv'd, That $ometimes the Quick-
+$ilver would for $ome days together re$t
+almo$t at the $ame height; and at other
+times again it would in the compa$s of the
+$ame day con$iderably vary its altitude,
+though there appear'd no change either in
+the Air abroad, or in the temper of the Air
+within the Room (wherein was con$tantly
+kept a good Fire) nor in any thing el$e, to
+which either I, or $ome eminently Learned
+Men whom I then acquainted with the
+Experiment, could rea$onably impute
+$uch a change: E$pecially con$idering that
+the $pace wherein the Mercury wandred up
+and down, within about five Weeks, a-
+mounted to full two Inches, of which we
+<pb n=132>
+found by our $everal marks whereby we
+had taken notice of its $everal removes, that
+it had de$c&etilde;ded about (9/16) of an Inch from the
+place where it fir$t $etled, &amp; the other Inch
+and (7/16) it had a$cended. And it $eems pro-
+bable that the height of the Mercurial Cy-
+linder would have varied yet more, if the
+Experiment had been made in the open
+Air and in a long Tube, where the Parti-
+cles of the Impri$on'd Air, by having
+more room to di$play them$elves in,
+might not have had $o $trong a Spring to
+work upon the Quick-$ilver with. But for
+want both of time and of a competent
+quantity of Mercury (which was not to be
+procur'd where we then happen'd to be)
+we were unable to make any further try-
+als: which therefore chiefly troubled us,
+becau$e we would gladly have try'd an in-
+genious Experiment which was $ugge$ted
+unto us by that excellent Mathematician
+Mr. <I>Wren,</I> who being invited to name any
+thing he would have us try touching the
+pre$$ure of the Air, de$ired us to ob$erve
+whether or no the Quick-$ilver in a long
+Tube would not a little vary its height ac-
+cording to the Tides, e$pecially about the
+New and Full Moon, about which times
+Mariners ob$erve tho$e great Flowings
+and Ebbs of the Sea, that they call the
+<pb n=133>
+Spring-Tides. For he $agaciou$ly and
+plau$ibly conjectur'd that $uch ob$ervati-
+ons accurately made, would di$cover the
+truth or erroneou$ne$s of the <I>Carte$ian
+Hypothe$is</I> concerning the Ebbing and
+Flowing of the Sea: which <I>Des Cartes</I>
+a$cribes to the greater pre$$ure made upon
+the Air by the Moon, and the Intercur-
+rent Ethereal Sub$tance at certain times
+(of the Day, and of the Lunary Moneth)
+then at others. But in regard we found
+the Quick-$ilver in the Tube to move up
+and down $o uncertainly, by rea$on, as it
+$eems, of accidental mutation in the Air;
+I $omewhat doubt whether we $hall finde
+the Altitude of the Quick-$ilver to vary
+as regularly as the Experiment is ingeni-
+ou$ly propo$'d. The $ucce$s we $hall (God
+permitting us to make tryal of it) acquaint
+Your Lord$hip with; and in the mean
+time take notice, that when we had occa-
+$ion to take the Tube out of the Frame
+(after it had $taid there part of <I>November</I>
+and part of <I>December</I>) a good Fire being
+then in the room, becau$e it was a Snowy
+day, we found the Quick-$ilver in the
+Tube to be above the upper $urface of
+the $ubjacent Mercury 29 Inches three
+quarters.
+<pb n=134>
+<p>If Your Lord$hip $hould now ask me
+what are the true cau$es of this varying al-
+titude of the Mercurial Cylinder; I $hould
+not undertake to an$wer $o difficult a que-
+$tion, and $hould venter to $ay no more,
+then that among divers po$$ible cau$es to
+which it may be a$cribed, it would not be,
+perhaps, ab$urd to reckon the$e that fol-
+low.
+<p>Fir$t then we may con$ider, that the Air
+in the upper part of the Tube is much
+more rarified, and therefore more weak
+then the external Air, as may appear by
+this among other things, That upon the in-
+clining of the Tube the Quick-$ilver will
+readily a$cend almo$t to the very top of
+it, and $o take up eight or nine tenth parts,
+and perhaps more of that $pace which it
+de$erted before: which would not happen
+if that whole $pace had been full of unra-
+rified Air, $ince that (as tryal may ea$ily
+$atisfie you) would not have $uffer'd it
+$elf to be thru$t into $o narrow a room by
+$o weak a pre$$ure. So that although in
+our Tube when the included Air was
+heated, the Quick-$ilver was $omewhat
+depre$$'d: Yet there is this difference be-
+twixt $uch a Tube and common Weather-
+Gla$$es, that in the$e the included and the
+<pb n=135>
+ambient Air are in an <I>&AElig;quilibrium</I> as to
+pre$$ure, and the weight of the Water
+that keeps them $eparate is $carce con$i-
+derable. Whereas in $uch a Tube as we
+are $peaking of, the Air within is very
+much more dilated then that without; and
+'tis not $o much the $pring or re$i$tance
+of the included Air, as the weight of the
+Mercurial Cylinder it $elf that hinders the
+Quick-$ilver from a$cending higher; for
+if we $hould $uppo$e that de$erted part of
+the Tube perfectly devoid of Air, yet
+would the Quick-$ilver ri$e but a little
+higher in it, and be far from filling it, in
+regard the outward Air would not be
+able to impel up $uch a weight much
+higher: whereas it may, by our former
+Experiments appear, that if all the Air in
+the upper part of a Weather-Gla$s were
+away, the Water would be impell'd up to
+the very top of it, though the Pipe were
+above thirty Foot long.
+<p>We may next con$ider, that this ra-
+rified Air at the upper part of our Tube
+being exactly $hut up betwixt the Gla$s
+and the Quick-$ilver, it was $carce $ubject
+to any di$cernable alterations, $ave tho$e
+it receiv'd from heat and cold.
+<pb n=136>
+<p>And we may further con$ider that yet
+the external Air or Atmo$phere is $ubject
+to many alterations, be$ides them that
+proceed from either of tho$e Quali-
+ties.
+<p>For the Experiment that occa$ion'd
+this Di$cour$e, $eems to make it proba-
+ble enough that there may be $trange
+Ebbings and Flowings, as it were, in the
+Atmo$phere; or at lea$t, that it may ad-
+mit great and $udden Mutations, either as
+to its Altitude or its Den$ity, from cau$es,
+as well unknown to us, as the effects are
+unheeded by us. And that You may not
+think that there is nothing in Nature but
+our Experiment that agrees with this our
+conjecture, we might put Your Lord$hip
+in minde of the Pains and Aches that are
+often complain'd of by tho$e that have
+had great Wounds or Brui$es, and that
+doe pre$age great Mutations in the Air
+oftentimes, whil$t to $trong and healthy
+Per$ons no $ign of any $uch thing appears.
+And that is al$o very memorable to this
+purpo$e, which I remember I have $ome-
+where read in a Book of the Ingenious
+<I>Kircherus,</I> who giving a pertinent admoni-
+tion concerning the various refractions
+that may happen in the Air, relates, That
+<pb n=137>
+during his $tay in <I>Malta,</I> he often $aw
+Mount <I>&AElig;tna,</I> though the next day, not-
+with$tanding its being extreamly clear, he
+could not $ee it; adding, that <I>Vintemillius,</I>
+a very Learned Per$on, did oftentimes,
+from a Hill he names, behold the whole
+I$land he calls <I>Luprica</I> protuberant above
+the Sea, though at other times, notwith-
+$tanding a clear Sky, he could not $ee it.
+And though perhaps this may be in part a-
+$cribed to the various light &amp; po$ition of
+the $un, or to the various di$po$ition of the
+Spectators eye, or peradventure to $ome
+other cau$e; yet the mo$t probable cau$e
+$eems to be the differing Den$ity of the
+Air, occa$ion'd by Exhalations capable to
+increa$e the refraction, and con$equently
+bring Beams to the Eye, which otherwi$e
+would not fall on it. We have likewi$e
+in another Treati$e mention'd our having
+often ob$erv'd with Tele$copes a plenty
+of Steams in the Air, which without $uch
+a help would not be taken notice of, and
+which as they were not at all times to be
+$een even through a Tele$cope, $o they
+did $ometimes, e$pecially after a $hower of
+Rain, ha$tily di$appear: and when we
+have vi$ited tho$e places that abound with
+Mines, we have $everal times been told
+<pb n=138>
+by the Diggers, that even when the Sky
+$eem'd clear, there would not $eldom $ud-
+denly ari$e, and $ometimes long continue,
+a certain Steam (which they u$ually call a
+damp) $o gro$s and thick, that it would
+oftentimes put out their very Candles, if
+they did not $ea$onably prevent it. And
+I think it will ea$ily be granted, that the
+a$cen$ion of $uch Steams into this or that
+part of the Air, and their mixing with it,
+are very like to thicken it; as on the o-
+ther $ide either heat or the $udden conden-
+$ation of the Air in another part of the At-
+mo$phere (to mention now no other cau-
+$es) are capable of rarifying it.
+<p>Nor will it very much import the main
+$cope of our Di$cour$e, whether it be
+$uppo$'d that the copious Steams the
+earth $ends into the air, thicken that part
+of the Atmo$phere that receives them,
+and make it more heavy: Or that $ome-
+times the Fumes may a$cend with $uch ce-
+lerity, that though the Air be thicken'd
+yet they rather dimini$h then en<*>ea$e its
+gravitation, in regard that the quickne$s
+of their a$cent, not onely keeps them
+from gravitating them$elves, but may
+hinder the pre$$ing downwards of many
+A&euml;rial Corpu$cles that they meet with in
+<pb n=139>
+their way upwards. This, I $ay, is of
+no great importance to our pre$ent Di$-
+cour$e, $ince either way the Terre$trial
+Steam may here and there con$iderably
+alter the gravity or pre$$ure of the At-
+mo$phere.
+<p>Your Lord$hip may al$o be plea$ed to
+remember, That by our $eventeenth Ex-
+periment it appear'd that as when the Air
+in the Receiver was expanded more then
+ordinarily, the Quick-$ilver in the Tube
+did proportionably $ub$ide; $o when the
+Air in the $ame Receiver was a little more
+then ordinarily compre$$'d, it did impell
+up the Quick-$ilver in the Tube above
+the wonted height of betwixt $ix and $e-
+ven and twenty digits.
+<p>And if to the$e things we annex, that
+for ought we can finde by tryals purpo$e-
+ly made, the degree of rarity or den$ity
+of the Air, $hut up into our Receiver, does
+not $en$ibly alter its temperature as to
+cold or heat. It will not, I hope, appear
+ab$urd to conceive, That $ince the Air,
+included in the Tube, could but very faint-
+ly hinder the a$cent of the Quick-$ilver,
+or pre$s it downwards, $ince too that inclu-
+ded Air could $carce immediately receive
+any $en$ible alteration, $ave either by heat
+<pb n=140>
+or cold. And $ince al$o that according to
+the bare den$ity or rarity of the Air in-
+cumbent on the $ubjacent Quick-$ilver in
+the Ve$$el, that in the Tube was impell'd
+more or le$s high; $uch changes happen-
+ing in the neighboring part of the out-
+ward Air, either by the a$cen$ion of gro$s
+or copious exhalations, or by any other
+cau$e (of which there may be divers) as
+were capable to make con$iderable altera-
+tions in the con$i$tence of the Air, as to
+rarity and den$ity, <I>may</I> be able propor-
+tionably to alter the heighth of the
+Quick-$ilver: I rather $ay, that $uch alte-
+rations <I>may</I> be, then that they <I>are</I> the
+cau$es of our <I>Ph&aelig;nomenon,</I> becau$e I think
+it $ufficient, if I have propo$'d conje-
+ctures not altogether irrational about a
+new My$tery of Nature, touching which,
+the chief thing I pretend to, is to give oc-
+ca$ion to the Curious to inquire further
+into it then I have been yet able to do.
+<p>THe $ame Rea$on that mov'd us to
+<MARG><I>Experi-
+ment</I> 19.</MARG>
+conclude, that by the drawing of the
+Air out of the Receiver, the Mercury
+would de$cend in a Tube $horter then $ix
+and twenty digits, induc'd us al$o to ex-
+<pb n=141>
+pect, that by the $ame means Water
+might be brought to $ub$ide in Gla$s
+Tubes of a moderate length, though by
+the noble Experiment, $aid to have been
+accurately made in <I>France</I> by <I>Mon$ieur
+Pa$chal,</I> we are informed that a Tube of
+no le$s then about two and thirty Foot,
+was found requi$ite to make the Experi-
+ment <I>De Vacuo</I> $ucceed with Water in-
+$tead of Quick-$ilver: $o tall a Cylinder
+of that lighter Liquor, being, it $eems,
+requi$ite to equal the weight of a Mercu-
+rial Cylinder of $ix or $even and twenty
+digits, and $urmount the pre$$ure of the
+Atmo$phere.
+<p>We took then a Tube of Gla$s, Her-
+metically $eal'd at one end, of about four
+foot in length, and not very $lender: This
+at the open end we fill'd with common
+Water, and then $topt that end till we
+had inverted the Tube, and open'd it be-
+neath the $urface of a quantity of the like
+Water, contain'd in a $omewhat deep and
+$lender Ve$$el. This Ve$$el, with the
+Tube in it, was let down into the Recei-
+ver, and the Receiver being clo$'d up af-
+ter the accu$tom'd manner, the Pump was
+$et awork.
+<pb n=142>
+<p>As much of the event as concerns our
+pre$ent purpo$e, was this, That till a con-
+$iderable part of the Air was drawn out
+of the Receiver, the Tube continu'd top-
+full of Water as when it was put in, it be-
+ing requi$ite that a great part of the Air
+formerly contain'd in the Receiver, $hould
+be drawn out, to bring the remaining
+Air to an <I>&AElig;quilibrium</I> with $o $hort and
+light a Cylinder of Water. But when
+once the Water began to fall in the Tube,
+then each ex$uction of Air made it de-
+$cend a little lower, though nothing near
+$o much as the Quick-$ilver at the begin-
+ning did in the Experiment formerly men-
+tion'd. Nor did there appear $o much
+inequality in the $paces tran$mitted by
+the Water in its de$cent, as there did in
+tho$e ob$erv'd in the fall of the Quick-
+$ilver, of which the cau$e will $carce $eem
+ab$tru$e to him that $hall duly reflect up-
+on what has been already deliver'd. And
+whereas we drew down the Quick-$ilver
+in the Tube $o far as to bring it within an
+Inch of the $urface of the other Quick-
+$ilver into which it was to fall; the lowe$t
+we were able to draw down the Water
+was, by our conjecture, to about a Foot
+<pb n=143>
+or more above the $urface of that in the
+Ve$$el; of which I know not whether it
+will be needful to a$$ign $o obvious a cau$e
+as that, though the little Air remaining
+in the Receiver could not hinder a Cylin-
+der of above an Inch high of Quick-$ilver
+from $ub$iding; yet it might very well
+be able, by its pre$$ure, to countervail the
+weight of a Cylinder of a Foot long or
+more, of a Liquor $o much le$s ponderous
+then Quick-$ilver, as Water is. And in
+fine, to conclude our Experiment, when
+the Water was drawn down thus low, we
+found, that by letting in the outward Air,
+it might be immediately impell'd up a-
+gain to the higher parts of the Tube.
+<p>We will adde no more concerning this
+Experiment, $ave that having try'd it in
+one of our $mall Receivers, we ob$erv'd,
+That upon the fir$t ex$uction of the Air
+the Water did u$ually $ub$ide divers In-
+ches, and at the $econd (ex$uction) fall
+down much lower, $ub$iding $ometimes
+near two Foot; as al$o that upon the let-
+ting in of the Air from without, the Wa-
+ter was impell'd up with very great ce-
+lerity.
+<pb n=144>
+<p>THat the Air has a notable Ela$tical
+<MARG><I>Experi-
+ment</I> 20.</MARG>
+power (whence$oever that proceeds)
+we have, I $uppo$e, abundantly evinc'd,
+and it begins to be acknowledg'd by the
+eminente$t Modern Naturali$ts. But whe-
+ther or no there be in Water $o much as
+a languid one, $eems hitherto to have been
+$carce con$ider'd, nor has been yet, for
+ought I know, determin'd either way by
+any Writer, which invited us to make the
+following Experiment.
+<p>There was taken a great Gla$s-bubble,
+with a long neck; ($uch as Chymi$ts are
+wont to call a Philo$ophical Egg) which
+being fill'd with common Water till the
+Liquor reach'd about a $pan above the
+bubble, and a piece of Paper being there
+pa$ted on, was put un$top'd into the Re-
+ceiver, and then the Air was $uck'd out
+after the wonted manner. The event was
+this, That a con$iderable part of the Air,
+pent up in the Receiver, was drawn out
+before we di$cern'd any expan$ion of the
+Water; but, continuing the labor of
+pumping, the Water manife$tly began to
+a$cend in the $tem of the Gla$s, and di-
+vers bubbles loo$ening them$elves from
+<pb n=145>
+the lower parts of the Ve$$el, made their
+way through the Body of the Water, to
+the top of it, and there brake into the
+Receiver: And after the Water once ap-
+pear'd to $well, then at each time the Stop-
+cock was turn'd to let out the air from the
+Receiver into the Pump, the Water in the
+Neck of the Gla$s did $uddenly ri$e a-
+bout the breadth of a Barly-corn in the
+Neck of the Gla$s, and $o attain'd, by
+degrees, to a con$iderable height above
+the mark formerly mention'd. And at
+length (to make the expan$ion of the Wa-
+ter more evident) the outward Air was
+$uddenly let in, and the Water immedi-
+ately $ub$ided and de$erted all the $pace it
+had newly gain'd in the Gla$s.
+<p>And, on this occa$ion, it will not per-
+haps be ami$s to acquaint Your Lord$hip
+here (though we have already mention'd
+it in another Paper, to another purpo$e)
+with another Expedient that we made u$e
+of two or three years ago, to try whether
+or no Water had a Spring in it. About
+that time then, That Great and Learned
+Promoter of Experimental Philo$ophy
+Dr. <I>Wilkins,</I> doing me the Honor to
+come him$elf, and bring $ome of his in-
+qui$itive Friends to my Lodging, we
+<pb n=146>
+there had in readine$s a round and hollow
+Ve$$el of Pewter, great enough to con-
+tain two pounds of Water, and exactly
+clo$e every where, but at one little hole
+where it was to be fill'd; then partly by
+$ucking out the Air, and partly by inject-
+ing Water with a Syringe, it was (not
+without $ome difficulty) fill'd up to the
+top; and that hole being plac'd directly
+upwards, there was a little more Water
+lei$urely forc'd in by the Syringe. Upon
+which, though the Ve$$el were permitted
+to re$t, and the hole kept in its former po-
+$ture, yet the compre$$'d Water lei$urely
+$well'd above the Orifice of the hole, and
+divers drops ran over along the $ides of the
+Ve$$el. After this, we cau$'d a skilful Pew-
+terer (who had made the Globe) to clo$e
+it up in our pre$ence with Soder $o exqui-
+$itely, that none $u$pected there was any
+thing left in it be$ides Water. And la$t-
+ly, the Ve$$el thus $oder'd up, was wari-
+ly and often $truck in divers places with a
+Wooden Mallet, and thereby was mani-
+fe$tly compre$$ d, whereby the inclo$ed
+Water was crouded into le$s room then it
+had before: And thereupon when we took
+a Needle, and with it and the Mallet per-
+forated the Ve$$el, and drew out the
+<pb n=147>
+Needle again; the Water (but in a very
+$lender Stream) was $uddenly thrown af-
+ter it into the Air, to the height of two
+or three Feet. As for the other <I>Ph&aelig;nome-
+na</I> of this Experiment, $ince they belong
+not to our pre$ent purpo$e, and are partly
+mention'd in another of our Papers, we
+$hall, in$tead of recording them here, give
+this Adverti$ement: That as evidently
+as this Experiment, and that made in our
+Receiver, $eem to prove a power in the
+Water to expand and re$tore it $elf after
+compre$$ion; yet for a rea$on to be met
+with ere long, I judged it not $afe to in-
+fer that Conclu$ion from the$e Premi$es,
+till I had made $ome of the following try-
+als, to the mention of which I will there-
+fore ha$ten.
+<p>TO di$cover whether the Expan$ion
+<MARG><I>Experi-
+ment</I> 21.</MARG>
+of the Water really proceeded
+from an Ela$tical power in the parts of
+the Water it $elf, we thought it requi$ite
+to try two things: The one, Whether or no
+the Atmo$phere gravitates upon Bodies
+under Water; and the other, Whether
+in ca$e it do gravitate, the Intume$cence
+of the Water may not be a$cribed to $ome
+<pb n=148>
+$ub$tance $ubtler then it $elf, re$iding m-
+it. In order to the $atisfying my $elf about
+the fir$t of the$e, I intended to let down
+into the Receiver a Ve$$el of Water,
+wherein $hould be immer$'d a very $mall
+oyl'd Bladder, almo$t devoid of Air, but
+$trongly <*>'d up at the Neck with a $tring,
+and detain'd a little under Water by $uch
+a weight fa$ten'd to that $tring, as $hould
+ju$t be able to keep the Bladder from
+$wimming, and no more. For I $uppo$'d,
+that if when all things were thus order'd,
+the Receiver were empty'd, in ca$e there
+were any $uch pre$$ure of the Atmo$phere
+upon Water, as I was inclin'd to believe,
+the Air within the Bladder, being upon the
+ex$uction of the Air within the Receiver,
+freed from that pre$$ure, and being pre$$'d
+onely by the $mall weight of the in-
+cumbent Water, would con$iderably ex-
+pand it $elf; but whil'$t we were prepa-
+ring Bladders for this Experiment, there
+occurr'd an ea$ie way for the making at
+once both the Di$coveries I de$ir'd.
+<p>We took then a Gla$s Viol, containing
+by ghe$s a pound and $ome ounces of
+Water, this we fill'd top full, and then
+we put into the Neck of it a Gla$s Pipe
+a pretty deal bigger then a Goo$e Quill,
+<pb n=149>
+open at both ends, and of divers Inches
+in length: One end of this Pipe was $o
+put into the Neck of the Viol, as to reach
+a little below it, and then was carefully
+cemented thereto that no Air might get
+into the Viol, nor no Water get out of
+it, otherwi$e then through the Pipe; and
+then the Pipe being warily fill'd, about
+half way up to the top, with more Wa-
+ter, and a mark being pa$ted over again$t
+the upper $urface of the Liquor; the Viol
+thus fitted with the Pipe, was, by $trings
+let down into the Receiver, and according
+to the wonted manner exqui$itely clo$'d
+up in it.
+<p>This done, we began to Pump out the
+Air, and when a pretty quantity of it had
+been drawn away, the Water in the Pipe
+began to ri$e higher in the Pipe, at the
+$ides of which $ome little bubbles di$co-
+ver'd them$elves. After a little while
+longer, the Water $till $welling, there
+appear'd at the bottom of the Pipe a bub-
+ble about the bigne$s of a $mall Pea,
+which a$cending through the Pipe to the
+top of the Water, $taid there awhile and
+then broke; but the Pump being nimbly
+ply'd, the expan$ion of the Water $o en-
+crea$'d, that quickly, getting up to the
+<pb n=150>
+top of the Pipe $ome drops of it be-
+gan to run down along the out-$ide of it,
+which oblig'd us to forbear pumping a-
+while, and give the Water leave to $ub-
+$ide within le$s then two Inches of the
+bottom of the Pipe. After this the
+Pump being again $et at work, the bub-
+bles began to a$cend from the bottom
+of the Pipe, being not all of a $ize, but yet
+$o big, that e$timating one with another,
+they appear'd to be of the $ize of the $mal-
+ler $ort of Peas; and of the$e we reckon'd
+about $ixty which came up one after ano-
+ther, be$ides $tore of $maller ones, of which
+we made no reckoning: And at length,
+growing weary of reckoning and pumping
+too (becau$e we found, that in $pight
+of all our pains and indu$try, $ome un-
+di$cern'd Leak or other in the Recei-
+ver hinder'd us from being able to empty
+it altogether) we thought fit to de$i$t for
+that time. After tryal made of what o-
+peration the external Air, being let in
+upon the expanded Water, would have;
+and accordingly turning the Key to let in
+the Air, we $aw, as we expected, that
+the Water in the Pipe in a moment fell
+down almo$t to the bottom of it.
+<pb n=151>
+<p>Now of this Experiment there are two
+or three Circum$tances yet to be men-
+tion'd, which are no le$s then tho$e alrea-
+dy recited, pertinent to our pre$ent pur-
+po$e.
+<p>In the fir$t place then, when the great-
+er part of the Air had been pump'd out of
+the Receiver, the ri$ing bubbles a$cend-
+ed $o very $lowly in the Pipe, that their
+Progre$s was $carce di$cernable; which
+$eem'd to proceed from this, That their
+bigne$s was $uch, That they could not
+$ufficiently extend them$elves in the
+cavity of the Gla$s, without pre$$ing
+on both hands again$t the $ides of it,
+whereby they became of more difficult
+extru$ion to the Water. And though it
+may $eem $trange the$e bubbles $hould
+be of any con$iderable bulk, $ince 'tis
+like they con$i$ted of le$$er parcels of
+the Air lurking in the Water, then tho$e
+that were vigorous enough to make their
+way through long before them: yet they
+were commonly much larger then before,
+$ome of them being equal in quantity to
+four or five Peas: Whether this their in-
+crea$e of bulk proceeded from the greater
+decrement of the pre$$ure of the Air,
+<pb n=152>
+or from the Union of two or three of
+tho$e numerous bubbles which were then
+generated below the bottom of the Pipe,
+where we could not $ee what was done a-
+mong them.
+<p>Another thing we noted in our bubbles
+was, That whereas in ordinary ones the
+Air, together with the thin film of Water
+that inve$ts and detains, is wont to $well
+above the $urface of the Water it $wims
+on, and commonly to con$titute Hemi$-
+pherical Bodies with it, the little parcels
+of Air that came up after the Receiver
+was pretty well empty'd, did not make
+protuberant bubbles, but $uch who$e up-
+per $urface was either level with or be-
+neath that of the Water, $o that the up-
+per $urface being u$ually $omewhat con-
+vex, the le$s protuberant parts of it had
+a pretty quantity of Water remaining a-
+bove them.
+<p>We al$o further ob$erv'd, That where-
+as in the bubbles that fir$t appear'd in
+the Pipe, the a$cending Air did, as in o-
+ther common bubbles, make its way up-
+wards, by dividing the Water through
+which it pa$$'d, in tho$e bubbles that ap-
+pear'd at the latter end of our Experi-
+ment, when the pre$$ure of the little ex-
+<pb n=153>
+ternal Air, remaining in the Receiver,
+was grown incon$iderable, the a$cending
+parcels of Air having now little more
+then the weight of the incumbent Water
+to $urmount, were able both $o to expand
+them$elves as to fill up that part of the
+Pipe which they pervaded, &amp; by pre$$ing
+every way again$t the $ides of it, to lift
+upwards with them what Water they
+found above them, without letting any
+con$iderable quantity glide down along
+the $ides of the Gla$s: So that $ometimes
+we could $ee a bubble thru$t on before it
+a whole Cylinder of Water of perhaps
+an Inch high, and carry it up to the top
+of the Pipe; though as we formerly no-
+ted, upon the letting in the external Air,
+the$e tumid bubbles $uddenly relap$'d to
+their former incon$picuou$ne$s.
+<p>All the$e things laid together $eem'd
+$ufficiently to confirm that, which the
+con$ideration of the thing it $elf would
+ea$ily enough per$wade, namely, That
+the Air, and $uch like Bodies being under
+Water, may be pre$$'d upon as well by
+the Atmo$phere, as by the weight of the
+incumbent Water it $elf.
+<p>Hence likewi$e we may verifie what we
+ob$erv'd at the clo$e of the foregoing
+<pb n=154>
+Experiment, namely, That from the $ole
+$welling of Water there recorded, it can-
+not be $o $afely concluded that Water,
+when freed from compre$$ion, is endowd
+with an Ela$tical power of expanding it
+$elf, $ince thereby it appears that the In-
+tume$cence produc'd by that Experiment,
+may (at lea$t in great part) be a$crib'd to
+the numerous little bubbles which are
+wont to be produc'd in Water, from
+which the pre$$ure of the Atmo$phere is
+in great mea$ure taken off. So apt are we
+to be mi$-led, even by Experiments them-
+$elves, into Mi$takes, when either we con-
+$ider not that mo$t Effects may proceed
+from various Cau$es, or minde onely tho$e
+Circum$tances of our Experiment, which
+$eem to comply with our preconceiv'd
+<I>Hypothe$is</I> or Conjectures.
+<p>And hence it $eems al$o probable, that
+in the Pores or invi$ible little rece$$es of
+Water it $elf there lie commonly inter-
+$per$'d many parcels of either Air, or at
+lea$t $omething Analogous thereunto, al-
+though $o very $mall that they have not
+been hitherto $o much as $u$pected to
+lurk there. But if it be demanded how it
+appears that there is inter$per$'d through
+the Body of Water any $ub$tance thinner
+<pb n=155>
+then it $elf, and why that which produc'd
+the bubbles above mention'd $hould not
+be re$olutely $aid to be nothing el$e then
+a more active and $pirituous part of the
+Water, we $hall, in order to the Elucida-
+tion of this matter, $ubjoyn to what
+was formerly deliver'd the following Ex-
+periment.
+<p>WE recited in our nineteenth Ex-
+periment, how by drawing mo$t
+<MARG><I>Experi-
+ment</I> 22.</MARG>
+of the Air out of the Receiver, we made
+the Water $ub$ide by degrees in a Gla$s
+not four Foot long: We $hall now adde,
+that in the like Experiment made in $uch
+a Tube, or a greater, it may be ob$erv'd,
+That when the Water begins to fall, there
+will appear $tore of bubbles fa$ten'd all a-
+long to the $ides of the Gla$s; of which
+bubbles, by the agitation of the Ve$$el
+con$equent upon pumping, there will ari$e
+good numbers to the top of the Water,
+and there break; and as the Cylinder of
+Water is brought to be lower and lower,
+$o the bubbles will appear more numerous
+in that part of the Tube which the Water
+yet fills; and the nearer the $urface of the
+Water, in its de$cent, approaches to the$e
+<pb n=156>
+bubbles, the greater they will grow, be-
+cau$e having the le$s weight and pre$$ure
+upon them, the Expan$ion of that Air
+which makes them, can be the le$s re$i$ted
+by the pre$$ure of the incumbent Water
+and Air; as $eems probable from hence,
+that upon the letting in a little external
+Air, tho$e bubbles immediately $hrink.
+<p>It may indeed, as we lately intimated,
+be conjectur'd, that the$e bubbles pro-
+ceed not $o much from any Air pre-exi-
+$tent in the Water, and lurking in the
+Pores of it, as from the more $ubtle parts
+of the Water it $elf; which by the expan-
+$ion allow'd them upon the dimini$h'd
+pre$$ure of the ambient Bodies may gene-
+rate $uch bubbles. And indeed, I am not
+yet $o well $atisfied that bubbles may not
+(at lea$t $ometimes) have $uch an Origina-
+tion: but that which makes me $u$pect
+that tho$e in our tryals contain'd real Air
+formerly latitant in the Pores of the Wa-
+ter, is this, That upon the inletting of
+the external Air, the Water was not
+again impell'd to the very top of the
+Tube whence it began to fall, but was
+$topt in its a$cent near an Inch beneath
+the top. And $ince, if the upper part of
+the Tube had been devoyd of any other
+<pb n=157>
+then $uch Ethereal matter as was $ubtle
+enough freely to penetrate the pores of
+the Gla$s, the external Air would have
+been able to impel the Water to the top
+of a Tube $even or eight times as long as
+ours was; The <I>Ph&aelig;nomenon</I> under con$i-
+deration $eem'd manife$tly to argue that
+the many bubbles that broke at the top
+of the Water did contain a real Air,
+which, being collected into one place and
+hinder'd by the top of the Gla$s from re-
+ceding, was able to with$tand the pre$$ure
+of the outward Air. As we $ee that if
+never $o little Air remain in the Tube up-
+on the making the Experiment <I>De Vacuo</I>
+with Quick-$ilver, no inclining of the
+Tube, though a long one, will enable a
+Man to impel the Mercury up to the very
+top, by rea$on (as we formerly noted)
+of the re$i$tance of the included Air, which
+will not be compre$$'d beyond a certain
+degree.
+<p>But in order to a further Di$covery what
+our bubbles were, we will, on this occa-
+$ion, inform Your Lord$hip that we try'd
+the XIX<SUP>th</SUP> <I>Experiment</I> in one of our $mall
+Receivers, and $ound, that upon the draw-
+ing down of the Water, $o many bubbles
+di$clo$'d them$elves and broke into the
+<pb n=158>
+upper part of the Tube, that having after-
+wards let in the external Air, the Water
+was not thereby impell'd to the top of the
+Tube (three Foot in length) within a lit-
+tle more then half an Inch. And whe-
+ther or no it were Air that po$$e$$'d that
+$pace at the top of the Tube which was
+not fill'd with Water, we took this cour$e
+to examine. We drew the $econd time
+the Air out of the Receiver, and found,
+that by rea$on of the body that po$$e$$'d
+the top of the Tube, we were able not
+onely to make the Water in the Tube fall
+to a level with the $urface of the Water
+in the Ve$$el: But al$o (by plying the
+Pump a little longer) a great way beneath
+it: which $ince it could not well be a$crib'd
+to the bare $ub$iding of the Water by rea-
+$on of its own weight, argued that the Wa-
+ter was depre$$'d by the Air: which was
+confirm'd by the Figure of the $urface of
+the Water in the Tube, which was much
+more concave then that of Water in
+Tubes of that bigne$s u$es to be. And
+this further tryal (to adde that upon
+the by) we made at the $ame time, That
+when the Water in the Pipe was drawn
+down almo$t as low as the Water without
+it, we ob$erv'd, that (though we de$i$ted
+<pb n=159>
+from pumping) by the bare application
+of a hand moderately warm to the de$ert-
+ed part of the Tube, the remaining Wa-
+ter would be $peedily and notably de-
+pre$$'d. And having for a while held a
+kindled Coal to the out$ide of the Tube,
+(the Pump being $till unimploy'd, becau$e
+the Ve$$el chanced to hold extraordinarily
+well) the Air was by the heat $o far ex-
+panded, that it quickly drave the Water
+to the bottom of the Tube, which was
+divers Inches beneath the $urface of the
+ambient Water. Whereby it appears (by
+the $ame way by which we formerly mea-
+$ur'd the dilatation of the Air) that the
+Air, even when it is expanded to between
+90 and 100 times, its extent will yet rea-
+dily admit of a much further rarifaction
+by heat.
+<p>I con$ider'd al$o that in ca$e the Bub-
+bles we have been $peaking of, were pro-
+duc'd by the parcels of Air latitant in the
+Water, that Air being now got together
+to the top of the Tube, though the Air
+were again drawn out of the Receiver,
+the taking off its pre$$ure would not di$-
+clo$e bubbles as before; and accordingly,
+the Air being again pump'd out, the Wa-
+ter in the Tube de$cended as formerly:
+<pb n=160>
+but for a great while we $carce $aw one
+bubble appear, onely when the Receiver
+had been very much exhau$ted, and the
+Water was fallen very low, there appear'd
+near the bottom of the Tube, certain
+little bubbles, which $eem'd to con$i$t of
+$uch parcels of Air as had not, by rea$on
+of their $malne$s, got up to the top of
+the Water, with the more bulkie and vi-
+gorous ones. And that which is not in-
+con$iderable, is, That having, by letting
+in the Air, forc'd up the Water into the
+Tube, we could not perceive that it a$-
+cended nearer the top, though we per-
+mitted the Engine to remain unimploy'd
+for two or three Nights together, and
+watch'd whether the Water would $well
+up and fill the Tube. And on this occa-
+$ion I remember, that having try'd $uch an
+Experiment as this with Quick-$ilver in-
+$tead of Water, in a Tube of about a Foot
+and a half long, wherein it might $eem
+more hopeful to e$cape bubbles; yet up-
+on the drawing down the Quick-$ilver as
+low as we could, and letting in the exter-
+nal Air upon it, we found that $ome lurk-
+ing particles of Air were got up to the top
+of the Tube, and hinder'd the Quick-
+$ilver from being forc'd up again $o high.
+<pb n=161>
+And though the Quick-$ilver were by
+this means brought to appear a very clo$e
+and lovely Metalline Cylinder, not inter-
+rupted by inter$per$'d bubbles as before;
+yet having cau$'d the Air to be again
+drawn out of the Receiver, I could per-
+ceive $everal little bubbles to di$clo$e
+them$elves, fa$ten'd to the in$ide of the
+Tube, near the bottom of it; and having
+purpo$ely watch'd one or two of the chief-
+e$t, I had the plea$ure to ob$erve, that
+though they grew bigger and bigger as
+the $urface of the Mercurial Cylinder fell
+nearer and nearer to them, $o as that at
+length they $well'd into a con$picuous
+bulk; yet upon the wary letting in the
+Air upon them, they did not break, but
+pre$ently $hrunk up into a littlene$s that
+render'd them incon$picuous.
+<p>Whence it $eems very probable, if not
+certain, that even in the clo$e$t and mo$t
+ponderous Liquors, and therefore much
+more in Water, there may lurk undi$cern-
+able parcels of Air, capable, upon the
+removal of the pre$$ure of the ambient
+Air (though but in part) and that of the
+Liquor wherein it lurks, to produce con-
+$picuous bubbles. And con$equently, if
+it $eem inconvenient to admit an Ela$tical
+<pb n=162>
+power in the Water, it may be $aid that
+the $welling of the compre$$'d Water in
+the Pewter Ve$$el lately mention'd, and
+the $pringing up of the Water at the hole
+made by the Needle, were not the effects
+of any internal <I>Elater</I> of the Water, but
+of the $pring of the many little particles
+of Air di$per$'d through that Water, and
+acting upon it in their $udden recovering
+them$elves to a greater extent, then that
+to which a violent compre$$ion had re-
+duc'd them.
+<p>But though, from all the$e particulars,
+it $eems manife$t that the bubbles we have
+been all this while treating of, were pro-
+duc'd by $uch a $ub$tance as may be pro-
+perly enough call'd Air; yet till we $hall
+have had the opportunity of making
+$ome further tryals concerning the nature
+of the Air, we $hall not re$olutely deter-
+mine whether or no Air be a Primogenial
+Body (if I may $o $peak) that cannot
+now be generated or turn'd either into
+Water or any other Body. Yet in the
+mean while (becau$e it is an important
+Que$tion, and if rightly determin'd, may
+much conduce to the knowledge of the
+<pb n=163>
+nature of the Air) We think it not unfit
+to make a brief mention of $ome of the
+particulars which at pre$ent occur to our
+thoughts in favor of either part of the
+Que$tion.
+<p>Fir$t then, divers Naturali$ts e$teem the
+Air (as well as other Elements) to be in-
+generable and incorruptible. And rea$ons
+plau$ible enough may be drawn to coun-
+tenance this Opinion from the con$idera-
+tion of that permanency that ought to
+belong to the corporeal Principles of o-
+ther Bodies.
+<p>Next, Experience may be pleaded to
+the $ame purpo$e, for I have read of $ome
+who have in vain attempted to turn Air
+into Water, or VVater into Air.
+<p>The diligent <I>Schottus</I> tells us, That a-
+<MARG><I>Schottus
+<*></I>
+Part 3.
+Cla$$. 1.</MARG>
+mong$t the other rarities to be met with
+in that great Repo$itory of them, the
+<I>Mu$&aelig;um Kercherianum,</I> there is a round
+Gla$s with a tapering Neck near half full
+(as one may gue$s by the Scheme he an-
+nexes) of ordinary Spring-water, which
+having been Hermetically $hut up there
+by <I>Clavius</I> the famous Geometrician,
+The included water is to this day pre-
+$erv'd, not onely clear and pure, as if
+it were but newly put in: But (as it $eems)
+<pb n=164>
+without (in the lea$t) turning into Air,
+notwith$tanding its having been kept
+there the$e fifty years: For he tells us,
+That the Water hath continued there all
+this while without any diminution.
+<p>Nor does it appear in tho$e Gla$$es,
+which for Chymical Experiments we u$u-
+ally clo$e with <I>Hermes</I> his Seal (as they
+call it) that the included Air does, during
+its long Impri$onment, notwith$tanding
+the alteration it receives from various de-
+grees of heat, di$cernably alter its nature.
+Whereas we plainly perceive in our Dige-
+$tions and Di$tillations, that though it
+may be rarified into invi$ible Vapors, yet
+it is not really chang'd into Air, but onely
+divided by heat, and $catter'd into very
+minute parts, which meeting together in
+the Alembick or in the Receiver, do pre-
+$ently return into $uch Water as they con-
+$tituted before. And we al$o $ee, that
+ev'n Spirit of Wine, and other $ubtle and
+fugitive Spirits, though they ea$ily fly in-
+to the Air, and mingle with it, do yet in
+the Gla$$es of Chymi$ts ea$ily lay a$ide
+the di$gui$e of Air, and re$ume the deve-
+$ted form of Liquors. And $o volatile
+Salts, as of Urine, Harts-horn, <I>&amp;c.</I> though
+they will readily di$per$e them$elves
+<pb n=165>
+through the Air, and play up and down in
+the capacity of an Alembick or a Recei-
+ver: yet will they, after a while, fa$ten
+them$elves to the in$ides of $uch Gla$$es
+in the form of Salts.
+<p>Be$ides, $ince Air is confe$$edly en-
+dow'd with an Ela$tical power that proba-
+bly proceeds from its Texture, it appears
+not what it is that in $uch light alterations
+of Water, as are by many pre$um'd ca-
+pable of turning it into Air, can be rea-
+$onably $uppo$'d $o to contrive the Parti-
+cles of Water, as to give them, and that
+permanently, the $tructure requi$ite to a
+Spring. I adde the word, Permanently,
+becau$e the newly mention'd ob$ervations
+$eem to argue the Corpu$cles of Air to
+be irreducible into Water, whereas the
+Aqueous Particles may perhaps for a
+while be $o vehemently agitated, as to
+pre$s almo$t like Springs upon other Bo-
+dies; yet upon the cea$ing of the agitati-
+on, they quickly, by relap$ing into Wa-
+ter, di$clo$e them$elves to have been no-
+thing el$e whil'$t they counterfeited the
+Air.
+<p>La$tly, The Experiment formerly made
+in our Engine with a piece of Match,
+$eems to evince, that even tho$e light and
+<pb n=166>
+$ubtle Fumes (for the mo$t part not aque-
+ous neither) into which the Fire it $elf
+$hatters dry Bodies, have no $uch Spring
+in them as the Air, $ince they were unable
+to hinder or repre$s the expan$ion of the
+Air included in the Bladder they $urroun-
+ded.
+<p>I remember indeed that the Learned
+<MARG><I>Natural &amp;
+<*> Hi$t.
+<*> In-
+<*>,</I> Lib. 3.
+<*> 9.</MARG>
+<I>Fo$ephus Aco$ta,</I> in his Hi$tory of the
+<I>We$t Indies,</I> tells us, That he $aw in tho$e
+parts $ome Grates of Iron $o ru$ted and
+con$um'd by the Air, that the Metal be-
+ing pre$$'d between the Fingers, di$$olv'd
+(to u$e his words) to powder, as if it had
+been Hay or parched Straw. And I re-
+<MARG><I>Geogr. Ge-
+<*>ral.</I> Lib.
+<*> 19.</MARG>
+member too, that the accurate <I>Varenius</I>
+tells us, That in the I$lands commonly
+called <I>Azores,</I> the Air (and Wind) is $o
+$harp, that in a $hort time it frets not only
+Iron Plates, but the very Tiles upon the
+Roofs of Hou$es, and reduces them to
+du$t. And I have el$ewhere mention'd
+$ome recent Ob$ervations of this kinde.
+But it may be $aid, That the above-men-
+tion'd Authors a$cribe the recited effects
+chiefly to the Winds, and that however
+the corro$ion of the Iron and the Tiles
+may proceed not from the Air it $elf, or
+any of its genuine parts, but from $ome
+<pb n=167>
+$aline Corpu$cles di$per$'d through the
+Air, and driven by the Winds again$t the
+Bodies it is pre$um'd to fret. And that
+$uch volatile Salts may copiou$ly a$cend
+into the Air, and yet retain their Nature,
+as doth the more fixt Salt in the Sea Wa-
+ter, the $ublimations of <I>Sal-Armoniack</I>
+may $ufficiently evince. Not to mention
+that I have $hown $ome Friends a $ecret
+kinde of $aline Sub$tance incomparably
+$ubtler then <I>Sal-Armoniack,</I> which did
+not onely ea$ily enough a$cend it $elf, but
+carried up with it (and that in a very great
+proportion) the $olid and ponderous Bo-
+dy ev'n of uncalcin'd Gold in the form of
+$ubtle exhalations, which did afterwards
+fa$ten them$elves to the upper parts of
+the Ve$$els, and yet manife$t them$elves
+to continue Gold. We remember al$o,
+that to try whether Water could be turn'd
+into Air, we once took an <I>&AElig;olipile,</I> into
+which we had before convey'd $ome Wa-
+ter, and placing it upon kindled Coals
+when the heat forc'd out a vehement
+$tream of aqueous Vapors; we ty'd about
+the neck of it, that of a Bladder, which
+we had before empty'd of Air; and find-
+ing the <I>&AElig;olipile</I> after a while to blow up
+the Bladder, we carefully ty'd it again
+<pb n=168>
+that the included $ub$tance might not get
+away. Then $lipping it off from the <I>&AElig;o-
+lipile</I> we convey'd it into our Receiver, to
+try whether or no that which in part di-
+$tended the Bladder would appear by its
+Spring to be true Air: whereby we found
+that upon the ex$uction of the ambient
+Air, the included $ub$tance expanded it
+$elf and the Bladder to a very much great-
+er bulk then it was of before. And for
+further $atisfaction, having again taken
+out the Bladder, we $uffer'd it to remain
+ty'd up till next morning, to try whether
+time, and the coldne$s of the night, would
+make the contain'd $ub$tance relap$e in-
+to Water: But the next Morning we
+found it little le$s tumid then before. I
+remember, I $ay, that I once made this
+Experiment; but I might $ay in an$wer
+to it, that the chief rea$on of my men-
+tioning it, is, To let Your Lord$hip $ee
+how requi$ite it is to be circum$pect and
+con$iderate, when we are to make and to
+build upon nice Experiments. For though
+I may $eem to have u$ed $ufficient cauti-
+on, yet afterward con$idering with my
+$elf that the <I>&AElig;olipile</I> I had imploy'd was
+a very large one, and that it required much
+more care then one that has not try'd it
+<pb n=169>
+would imagine, to drive out all the Air
+from a large <I>&AElig;olipile,</I> I ea$ily $u$pected
+that the di$ten$ion of the Bladder in our
+pneumatical Ve$$el, might proceed not
+from the Watery $teams that came out at
+the narrow mouth of the <I>&AElig;olipile,</I> and
+had very much wetted the Bladder, but
+from the rarified Air which in that $ort of
+Ve$$els is wont for a good while together
+to come out with the rarified Water: and
+accordingly having reiterated the Experi-
+ment I found it very difficult (by rea-
+$on of the $hrinking of the Bladders (up-
+on their being heated) and of other impe-
+diments) to make it $o accurately as to de-
+duce from it, that Water may be rarified
+into true Air.
+<p>Again$t the four other above-mention'd
+Con$iderations, we cannot $pend time to
+frame Objections, but mu$t forth with
+proceed to the mention of tho$e things
+that $eem to argue that Air (at lea$t $uch
+as produc'd our bubbles) maybe gene-
+rated of Water and other Bodies.
+<p>Fir$t then we have found by Experi-
+ence that a vapid Air, or Water rarified
+into vapor, may at lea$t for a while emu-
+late the ela$tical power of that which is
+generally acknowledg'd to be true Air.
+<pb n=170>
+For if you take a good <I>&AElig;olipile,</I> with a
+moderately $trong and $lender Neck, and
+filling it with Water, lay it upon quick
+Coals, you may after a while ob$erve $o
+great a pre$$ure by $ome of the parts con-
+tain'd in the <I>&AElig;olipile</I> upon others, that
+the Water will $ometimes be thrown up
+into the Air above three or four Foot
+high; and if you then take the <I>&AElig;olipile</I>
+almo$t red hot from off the Fire, you may
+perceive that the Water will for a longer
+time then one would ea$ily imagine con-
+tinue to be $pouted out in a violent
+Stream. And if there remains but little
+Water in the <I>&AElig;olipile</I> when tis taken ve-
+ry hot from the Fire, immerfing the
+Neck of it into cold Water, you will
+finde, that after it begins to $uck in $ome
+Water, there will be made from time to
+time $tore of large bubbles in that Water
+where into the neck was plunged. Which
+bubbles $eem manife$tly to proceed from
+hence, that for a while the heat in the <I>&AElig;-
+olipile</I> continues $trong enough to rarifie
+part of the Water that is $uck'd in, and
+expel it in the form of Vapors through
+the Water incumbent on the Pipe. If al-
+$o when the <I>&AElig;olipile</I> is almo$t full of wa-
+ter, and therefore can contain but little
+<pb n=171>
+Air; you hold a Coal or Brand in that
+$tream of Vapors that i$$ues out of the
+narrow mouth of it, you will finde this
+vapid or rorid Air, (if I may $o call it)
+to blow the Fire very $trongly and with a
+roaring noi$e. And that it be not $aid
+that 'tis by the external Air which the a-
+queous $teams drive before them, and
+not by the Steams them$elves, that the
+Bla$t is made and the Flame excited; it
+has been ob$erv'd, that by approaching
+the Coal or Brand almo$t to the mouth
+of the <I>&AElig;olipile,</I> the winde appear'd more
+vehement then if the Body to be kindled
+were held $ome Inches off.
+<p>But in regard the ela$tical power of the
+Stream, i$$uing out of an <I>&AElig;olipile,</I> $eems
+manife$tly due to the heat that expands
+and agitates the aqueous Particles where-
+of that Stream con$i$ts, and that $uch
+rapid winds $eem to be but water $catter'd
+into little parts and $et a moving; $ince
+we finde, that holding a Knife, or any
+$olid, $mooth and clo$e Body again$t the
+$tream that i$$ues out of the &AElig;olipile, the
+vapors conden$ing upon it, will pre$ently
+cover it with water: It will be very per-
+tinent to $ubjoyn a notable Experiment
+that I remember I have met with in the
+<pb n=172>
+de$cription given us by the Indu$trious
+<I>Kircher,</I> of $everal Mu$ical Engines. And
+(though it may $eem $omewhat prolix)
+we will recite what he delivers in his own
+words, which are the$e.
+<p><I>Cum codem tempore quo h&aelig;c $crip$i</I>
+<MARG><I><*>: Art:
+Mag: Cun:
+&amp; Di$$on:
+<*>.</I> 9.
+<*> 309.</MARG>
+<I>$ummi Pont: Innocentii</I> X<SUP>mi</SUP> <I>mandato or-
+gani hydraulici in horto Quirinali con$ti-
+tuendi cur a mihi commendata e$$et; &AElig;oliam
+camer am in$igni $ane $ucce$$u con$trui ju$si-
+mus, e&aacute; qu&aelig; $equitur ratione.</I>
+<p><I>Erat longitudo $ive altitudo camer&aelig;</I> AH
+5 <I>Pedum, Latitudine</I> 3 <I>fere ex lateribus</I>
+<MARG><I>See the fif-
+<*> Fi-
+gure,</I></MARG>
+<I>con$tructa; in medio duo tenebat Diaphrag-
+mata</I> CD <I>&amp;</I> EJ <I>in modum cribri pluri-
+bus for aminibus pertu$a. Paulo infra ca-
+nalis</I> G <I>aquam advehens in$erebatur in</I> H
+<I>eidem epi$tomium par ab at exitum. Aqua
+it &aacute;que per canalem</I> G <I>maximo impetu ruens
+vehementi$simum ventum mox intus exci-
+t ab at; qui ventus nimia humiditate imbu-
+tus, ut purior exiret $iccior&queacute;, Diaphrag-
+mata ill a in cribri modum pertu$a, or dinata
+$unt. Intra h&aelig;c enim aqu&aelig; vehemens agi-
+tatio rupta fracta&queacute; aerem puriorem per</I> A
+<I>canalem $ubtilioremque emittebat: Verum
+cum po$tea invent&utilde; $it aer&etilde; plus &aelig;quo humi-
+d&utilde; interioribus Organi meatibus maxim&utilde;
+detrimentum inferre: Hinc ut aer aquo$us</I>
+<pb n=173>
+<I>$icci$simam c&otilde;$i$tentiam acquireret, ordina-
+vimus canalem plumbeum</I> QR <I>in helicem
+contortum va$i</I> S <I>aliquantulum capaciori in
+modum Urn&aelig; efformato, in$ertum. Intra
+urnam enim plumbeam &amp; canalem tortuo-
+$um illi$us aer humidus, it a ab omni aquo$i-
+tate def&aelig;cabatur, ut ex furno in Organum
+derivatus dici potuerit. Urna</I> S <I>canalis
+tortuo$us</I> QR <I>ultimum orificium</I> Q <I>in$e-
+ritur anemothec&aelig; organi. Et hunc modum
+organis hydraulicis omni&utilde; apti$sim&utilde; reperi.</I>
+<p><I>Debet autem camer&aelig; illa $ituari in loco
+quantum fieri pote$t $icciori it a ut longo ca-
+nali aqua intr a eam derivetur ne locus hu-
+miditate $ua Organis officiat.</I>
+<p>Thus far the Ingenious <I>Kircherus,</I> whom
+I the rather cite, becau$e although I have
+been informed of divers Ventiducts (as
+they call them) by very knowing Tra-
+vellers that have ob$erv'd them: Yet this
+relation of our Author being very pun-
+ctual, and deliver'd upon his own particu-
+lar Experience, has, I confe$s, made me
+wi$h I had had the good fortune when I
+was at <I>Rome,</I> to take notice of the$e Or-
+gans; or that I had now the opportunity
+of examining of $uch an Experiment.
+For if upon a $trict inquiry I $hould find
+that the breath that blows the Organs
+<pb n=174>
+does not really upon the cea$ing of its un-
+u$ual agitation by little and little relap$e
+into water, I $hould $trongly $u$pect that
+'tis po$$ible for Water to be ea$ily turn'd
+into Air. I remember indeed, that we
+have formerly taught that there lurks an
+inter$per$ed Air in the pores of ordinary
+Water, which may po$$ibly be $truck out
+by the breaking of the Water in its fall
+into the &AElig;olian Chamber, (as he calls it.)
+But in regard the Scheme $eems to repre-
+$ent that Chamber as clo$ely $hut, and
+thereby forbids us to $uppo$e that any Air
+is carried into it but what is latitant in the
+Water, it will $carce $eem probable to
+him who remembers how $mall a propor-
+tion of Air, that appear'd to be when its
+rarification $ea$ed, which was conceal'd in
+the Water we freed from bubbles in our
+Receiver, that $o little Air as is common-
+ly di$per$'d through Water, $hould be a-
+ble, in $o little Water as was requi$ite for
+$o $mall a room, to make $o vehement a
+Wind as our Author here tells us of. I
+have $ometime therefore $u$pected, that
+in this ca$e the Wind may be produc'd by
+$mall particles of the water it $elf, forci-
+bly expell'd out of the Chamber into the
+Organs. And to the Objection to which
+<pb n=175>
+I fore$aw this ghe$s to be liable, namely,
+That, no heat intervening, there appear'd
+nothing that $hould rai$e the Water into
+exhalations and give them an impul$e. I
+thought it might be $aid that motion a-
+lone, if vehement enough, may, with-
+out $en$ible heat, $uffice to break Water
+into very minute parts, and make them a$-
+cend upwards, if they can no where el$e
+more ea$ily continue their agitation. For
+Iremember, that Travelling betwixt <I>Ly-
+ons</I> and <I>Geneva,</I> I $aw, not very far out of
+the Way, a place where the River of
+<I>Rhone</I> coming $uddenly to be $treighten'd
+betwixt two Rocks, $o near each other,
+that a Man may (if my Memory fail me
+not) $tand a$tride upon both at once: that
+rapid Stream da$hing with great impetuo-
+$ity again$t its Rocky Boundaries, does
+break part of its Water into $uch minute
+Corpu$cles, and put them into $uch a mo-
+tion, that Pa$$engers ob$erve at a good di-
+$tance off, as it were a Mi$t ari$ing from
+that place, and a$cending a good way up
+into the Air. Such, I $ay, was my $u$-
+picion touching the Wind we have been
+con$idering, but it $eems $omething odde
+that aqueous Vapors $hould, like a dry
+Wind, pa$s through $o long and tortu-
+<pb n=176>
+ous a Pipe of Lead, as that de$crib'd by
+our Author, $ince we $ee in the Heads of
+Stills, and the Necks of <I>&AElig;olipiles,</I> how
+quickly $uch vapors are even by a very lit-
+tle cold reconden$ed into Water. But
+to this al$o $omething may be $peciou$ly
+reply'd; wherefore contenting my $elf to
+have mention'd our Authors Experiment
+as a plau$ible, though not demon$trative
+proof, that Water may be tran$muted in-
+to Air. We will pa$s on to mention in
+the third place another Experiment, which
+we try'd in order to the $ame enquiry.
+<p>We took a clear Gla$s bubble (capable
+of containing by ghe$s about three Oun-
+ces of Water) with a Neck $omewhat
+long and wide, of a Cylindrical form;
+this we fill'd with Oyl of Vitriol and fair
+water, of each almo$t a like quantity, and
+ca$ting in half a dozen $mall Iron Nails,
+we $topt the mouth of the Gla$s (which
+was top-full of Liquor) with a flat piece
+of <I>Diapalma</I> provided for the purpo$e,
+that accommodating it $elf to the $urface
+of the water, the Air might be exqui-
+$itely excluded: and $peedily inverting
+the Viol, we put the Neck of it into a
+$mall wide-mouth'd Gla$s that $tood rea-
+dy with more of the $ame Liquor in it, to
+<pb n=177>
+receive it. As $oon as the neck had reach'd
+the bottom of the Liquor it was dipp'd
+into, there appear'd at the upper part
+(which was before the bottom) of the
+Viol a bubble, of about the bigne$s of
+a Pea, which $eem'd rather to con$i$t of
+$mall and recent bubbles, produc'd by the
+action of the di$$olving Liquor upon the
+Iron, then any parcel of the external Air
+that might be $u$pected to have got in
+upon the inver$ion of the Gla$s, e$peci-
+ally $ince we gave time to tho$e little
+Particles of Air which were carried down
+with the Nails into the Liquor to fly up
+again. But whence this fir$t bubble was
+produced, is not $o material to our Expe-
+riment, in regard it was $o $mall: For
+$oon after we perceiv'd the bubbles
+produced by the action of the <I>Men-
+$truum,</I> upon the Metal a$cending co-
+piou$ly to the bubble already named, and
+breaking into it, did $oon exceedingly in-
+crea$e it, and by degrees depre$s the wa-
+ter lower and lower, till at length the $ub-
+$tance contain'd in the$e bubbles po$$e$$ed
+the whole cavity of the Gla$s Viol, and
+almo$t of its Neck too, reaching much
+lower in the Neck then the $urface of the
+ambient Liquor, wherewith the open-
+mouth'd Gla$s was by this means almo$t
+<pb n=178>
+repleni$hed. And becau$e it might be
+$u$pected that the depre$$ion of the Li-
+quor might proceed from the agitation
+whereinto the exhaling and impri$on'd
+$teams were put, by that heat which is
+wont to re$ult from that action of corro-
+$ive $alts upon Metals, we $uffered both
+the Viol and the open-mouthed Gla$s to
+remain as they were, in a Window, for
+three or four days and nights together; but
+looking upou them $everal times during
+that while, as well as at the expiration of
+it, the whole cavity of the Gla$s bubble,
+and mo$t of its Neck, $eem'd to be po$-
+$e$$'d by Air, $ince by its $pring it was a-
+ble for $o long to hinder the expell'd and
+ambient Liquor from regaining its former
+place. And it was remarkable, that ju$t
+before we took the Gla$s bubble out of
+the other Gla$s, upon the application
+of a warm hand to the convex part of the
+bubble; the Impri$on'd $ub$tance readily
+dilated it $elf like Air, and broke through
+the Liquor in divers bubbles, $ucceeding
+one another.
+<p>Having al$o another time try'd the like
+Experiment with a $mall Viol, and with
+Nails di$$olv'd in <I>Aquafortis,</I> we found
+nothing incongruous to what we have
+now deliver'd. And this Circum$tance
+<pb n=179>
+we ob$erv'd, that the newly generated
+$teams did not onely po$$e$s almo$t all the
+whole cavity of the Gla$s, but divers
+times without the a$$i$tance of the heat of
+my hand, broke away in large bubbles
+through the ambient Liquor into the o-
+pen Air: So that the$e Experiments
+with corro$ive Liquors, $eem'd manife$t-
+ly enough to prove, though not that Air
+may be generated out of the Water, yet
+that in general air may be generated anew.
+<p>La$tly, to the foregoing Arguments
+from Experience we might ea$ily $ubjoyn
+the Authority of <I>Ari$totle,</I> and of (his
+followers) the Schools who are known to
+have taught, that Air and Water being
+Symbolizing Elements (in the quality of
+moi$ture) are ea$ily tran$mutable into one
+another. But we $hall rather to the fore-
+going Argument adde this, drawn from
+Rea$on, That if, as <I>Leucippus, Democri-
+tus, Epieurus</I> and others, follow'd by
+divers modern Naturali$ts, have taught,
+the difference of Bodies proceeds but
+from the various Magnitudes, Figures,
+Motions, and Textures of the $mall
+parts they con$i$t of, (all the quali-
+ties that make them differ, being de-
+ducible from thence) there appeares
+<pb n=180>
+no rea$on why the minute parts of Wa-
+ter, and other Bodies, may not be $o agi-
+tated or connected as to de$erve the name
+of Air. For if we allow the <I>Carte$ian
+Hypothe$is,</I> according to which, as we no-
+ted at the beginning of this Letter, the
+Air may con$i$t of any terrene or aqueous
+Corpu$cles, provided they be kept $wim-
+ming in the interfluent Cele$tial Matter;
+it is obvious that Air may be as often ge-
+nerated, as Terre$trial Particles minute
+enough to be carried up and down, by the
+Cele$tial Matter a$cend into the Atmo-
+$phere. And if we will have the Air to
+be a <I>congeries</I> of little $lender Springs, it
+$eems not impo$$ible, though it be diffi-
+cult, that the $mall parts of divers Bo-
+dies may by a lucky concour$e of cau$es
+be $o connected as to con$titute $uch
+little Springs, $ince (as we note in another
+Treati$e) Water in the Plants it nouri$hes
+is u$ually contriv'd into Springy Bodies,
+and even the bare alter'd po$ition and con-
+nexion of the parts of a Body may $uf-
+fice to give it a Spring that it had not be-
+fore, as may be $een in a thin and fiexible
+Plate of Silver; unto which, by $ome
+$troaks of a Hammer, you may give a
+Spring, and by onely heating it red hot
+<pb n=181>
+you may make it again flexible as be-
+fore.
+<p>The$e, My Lord, are $ome of the
+Con$iderations at pre$ent occurring to
+my thoughts, by which it may be made
+probable that Air may be generated a-
+new. And though it be not impo$$ible
+to propo$e Objections again$t the$e, as
+well as again$t what has been repre$ented
+in favor of the contrary Doctrine; yet
+having already almo$t tyr'd my $elf, and
+I fear more then almo$t tyr'd Your Lord-
+$hip with $o trouble$ome an Enquiry af-
+ter the Nature of bubbles, I $hall wil-
+lingly leave Your Lord$hip to judge of
+the Arguments alledged on either $ide,
+and I $hould $carce have ventur'd to enter-
+tain You $o long concerning $uch empty
+things as the Bubbles, which have occa-
+$ion'd all this Di$cour$e, but that I am
+willing to invite You to take notice with
+me of the ob$curity of things, or the dim-
+ne$s of our created Intellects (which yet
+of late too many $o far pre$ume upon, as
+either to Deny or Cen$ure the Almighty
+and Omni$cient Creator him$elf) and to
+learn hence this Le$$on, That there are
+very many Things in Nature that we di$-
+dainfully over-look as obvious or de$pi-
+<pb n=182>
+cable, each of which would exerci$e our
+Under$tandings, if not po$e them too, if
+we would but attentively enough con$ider
+it, and not $uperficially contemplate, but
+attempt $atisfactorily to explicate the na-
+ture of it.
+<p>SInce the writing of the twenty one and
+<MARG><I>Experi-
+ment</I> 23.</MARG>
+twenty $econd Experiments (and not-
+with$tanding all that hath been on their
+occa$ion deliver'd concerning bubbles) we
+made $ome further tryals in pro$ecution
+of the $ame inquiry whereto they were
+de$igned.
+<p>We cho$e then, among$t tho$e Gla$$es
+which Chymi$ts are wont to call Philo$o-
+phical Eggs, one that containing about
+nine Ounces of Water, had a Neck of
+half an Inch in Diameter at the top, and
+as we ghe$t, almo$t an Inch at the bot-
+tom; which breadth we pitch'd upon for
+a rea$on that will by and by appear: then
+filling it with common Water to the
+height of about a Foot and a half, $o
+that the upper part remain'd empty, we
+$hut it into the Receiver, and watch'd what
+would follow upon pumping, which pro-
+<pb n=183>
+ved that a great part of the Air being
+drawn out, the bubbles began to di$cover
+them$elves at the bottom and $ides of the
+Gla$s; and increa$ing, as the Air was
+more and more drawn away, they did
+from time to time a$cend copiou$ly e-
+nough to the top of the Water, and there
+quickly break: but by rea$on that the
+widene$s of the Gla$s allow'd them free
+pa$$age through the Water, they did not
+appear as in the former Experiments to
+make it $well: The Water $carce ever ri-
+$ing at all above the mark affixt to its up-
+per $urface when it was put in, and upon
+the return permitted to the outward Air,
+and con$equently the $hrinking in of the
+remaining bubbles, the Water $eem'd to
+have lo$t of its fir$t extent, by the avo-
+lation of the formerly inter$per$'d Air.
+<p>Being willing likewi$e to try whether
+di$tilled Water were by having been di-
+vided into minute parts, and then re-uni-
+ted, more or le$s di$po$'d to expand it
+$elf then Water not di$till'd: We took
+out of our Laboratory $ome careful-
+ly di$till'd Rain-water, and put about
+two Ounces of it into a round Gla$s
+<pb n=184>
+bubble with a very $mall Neck (not ex-
+ceeding the $ixth part of an Inch in Dia-
+meter) which we fill'd half way to the
+top, and then convey'd it into the Recei-
+ver; the i$$ue was, That though we drew
+out more then ordinary, yet there ap-
+pear'd not the lea$t intume$cence of the
+Water, nor any a$cending bubbles.
+<p>But $u$pecting that either the $mall
+quantity of the water or the Figure of the
+Ve$$el might have an intere$t in this odde
+<I>Ph&aelig;nomenon,</I> we took the lately mention'd
+Philo$ophical Egge, and another not
+much differing from it; the former we
+fill'd up with di$till'd Rain-water to the
+old mark, and into the latter we put a
+long Cylinder or Rod of $olid Gla$s to
+$treighten the cavity of the Neck by al-
+mo$t filling it up; and then pouring $ome
+di$tilled Water into that al$o, till it
+reach'd within $ome Fingers breadth of
+the top, the Eggs were let down into the
+Receiver. In this Experiment the Air
+was $o far drawn forth before there ap-
+pear'd any bubble in either of the Gla$$es,
+that the di$parity betwixt this and com-
+mon water was manife$t enough. But at
+length, when the Air was almo$t quite
+pump'd out, the bubbles began to di$-
+<pb n=185>
+clo$e them$elves, and to increa$e as the
+pre$$ure of the Air in the Receiver de-
+crea$'d. But whereas in the fir$t men-
+tion'd Philo$ophical Egge the bubbles
+were very $mall, and never able to $well
+the Water, that we took notice of, at all
+above the mark: In the other, who$e
+Neck, as we lately $aid, was $traightned,
+and their pa$$age ob$tructed, great num-
+bers of them, and bigger, fa$tned them-
+$elves to the lower end of the Gla$s ram-
+mer (if we may $o call it) and gather'd in
+$uch numbers between that and the $ides
+of the Neck, that the Water $well'd a-
+bout a Fingers breadth above the mark,
+though upon the admitting of the exter-
+nal Air it relap$'d to the former mark, or
+rather fell $omewhat below it. And al-
+though thereupon in the fir$t nam'd Ve$-
+$el all the bubbles pre$ently di$-appear'd,
+yet in the other we ob$erv'd, that divers
+remained fa$tned to the lower part of the
+Gla$s rammer, and continued there $ome-
+what to our wonder, for above an hour
+after, but contracted in their Dimen-
+$ions.
+<p>Moreover, having $uffered the Gla$$es
+to remain above twenty four hours in the
+<pb n=186>
+Receiver, we afterwards repeated the Ex-
+periment, to try what change the ex$ucti-
+on of the external Air would produce in
+the Water, after the internal and latitant
+Air had (as is above recited) in great mea-
+$ure got away in bubbles, and whether or
+no the Water would by $tanding re-admit
+any new particles of Air in the room of
+tho$e that had for$aken it. But though
+we exhau$ted the Receiver very diligent-
+ly, yet we $carce $aw a bubble in either
+of the Gla$$es; notwith$tanding which,
+we perceiv'd the Water to ri$e about the
+breadth of a Barly-corn, or more, in the
+Neck of that Gla$s wherein the $olid Cy-
+linder had been put; The Liquor in the
+other Gla$s not $en$ibly $welling.
+<p>And la$tly, upon the letting in of the
+Air, the Water in the $traightned Neck
+$oon $ub$ided to the mark above which
+it had $wollen, which whether it ought
+to be a$crib'd to the $ame $mall expan$ion
+of the parts of the Water it $elf, or to
+the rarifaction of $ome yet latitant Air
+broken into $uch $mall particles, as to e-
+$cape our ob$ervation, $eems not ea$ily
+determinable, without $uch further tryals,
+as would perhaps prove tedious to be re-
+cited as well as to be made; though I was
+<pb n=187>
+content to $et down tho$e already men-
+tion'd, that it might appear how requi-
+$ite it is in nice Experiments to con$ider
+variety of Circum$tances.
+<p>AFter having thus di$cover'd what ope-
+<MARG><I>Experi-
+ment</I> 24.</MARG>
+ration the ex$uction of the ambient
+Air had upon Water, we thought good
+to try al$o what changes would happen in
+other Liquors upon the like taking off the
+pre$$ure of the external Air. We took
+then a Gla$s Egge, $omewhat bigger then
+a Turkey Egge, which had a long Neck
+or Stem of about a 1/3 part of an Inch in
+Diameter; and filling it up with Sallet
+Oyl until it reach'd above half way to the
+top of the Neck, we inclo$'d it in the Re-
+ceiver together with common Water in
+a re$embling Ve$$el, that we might the
+better compare together the operation of
+the ex$uction of the Air upon tho$e two
+Liquors. The Pump being $et a work there
+began to appear bubbles in the Oyl much
+$ooner then in the Water, and afterwards
+they al$o a$cended much more copiou$ly
+in the former Liquor then the latter: Nay,
+and when by having quite tired the Pum-
+per, and almo$t our own patience, we
+<pb n=188>
+gave over, the bubbles ri$e almo$t (if
+not altogether) in as great numbers
+as ever, in$omuch as none of the various
+Liquors we tryed either before or $ince,
+$eem'd to abound more with Aerial Parti-
+cles then did this Oyl. In which it was
+further remarkable, that between the time
+it was $et into the Receiver, and that at
+which we could get ready to Pump, it $ub-
+$ided notably (by ghe$s about half an
+Inch) below the mark it reach'd before it
+was put in.
+<p>After this expre$$'d Oyl, we made tryal
+of a di$till'd one, and for that purpo$e
+made choice of the common Oyl or Spi-
+rit (for in the Shops where it is $old, the
+$ame Liquor is promi$cuou$ly call'd by ei-
+ther name) of Turpentine; becau$e 'twas
+onely of that Chymical Oyl, we had a
+$ufficient quantity: which, being put in-
+to a $mall Gla$s bubble with a $lender
+Neck, $o as to fill it to about two Inches
+from the top, did, upon the evacuating
+of the Receiver, pre$ent us with great
+$tore of bubbles; mo$t of which ri$ing
+from the bottom, expanded them$elves
+exceedingly in their a$cent, and made the
+Liquor in the Neck to $well $o much by
+degrees, that at length it divers times ran
+<pb n=189>
+over at the top: by which means, we
+were hindred from being able to di$cern
+upon the letting in of the Air, how much
+the $ub$idence of the Oyl below the fir$t
+mark was due to the rece$s of the bub-
+bles.
+<p>Having likewi$e a minde to try whe-
+ther as $trong a $olution of Salt of Tartar
+in fair Water as could be made (we ha-
+ving then no Oyl of Tartar <I>per deliqui-
+um</I> at hand) though it be accounted,
+Quick-$ilver excepted, the heavie$t of
+Liquors would afford us any bubbles; we
+put in a Gla$s Egge full of it at the $ame
+time, with other Liquors, and found that
+they did long yield $tore of bubbles be-
+fore any di$covered them$elves in the
+Liquor of Tartar; and having pur$ued
+the Experiment, it appear'd, That of all
+the Liquors we made tryal of, this afford-
+ed the fewe$t and the $malle$t Bubbles.
+<p>Spirit of Vinager being try'd after the
+$ame manner, exhibited a moderate num-
+ber of bubbles, but $carce any thing el$e
+worth the mentioning.
+<p>Nor could we in red Wine, try'd in a
+Gla$s Egge, take notice of any thing ve-
+ry ob$ervable. For though upon the ex-
+$uction of the Air the bubbles a$cended
+<pb n=190>
+in this Liquor, as it were in $holes,
+and $hifted places among them$elves in
+their a$cent; yet the Intume$cence of the
+whole bulk of the Liquor was $carce at all
+$en$ible, the bubbles mo$t commonly
+breaking very $oon after their arrival at
+the top, where during their $tay, they
+compo$'d a kinde of $hallow froth, which
+alone appear'd higher in the Neck of the
+Gla$s, then was the Wine when it was
+fir$t let down. Neither yet did Milk, con-
+vey'd into our Pneumatical Ve$$el, pre-
+$ent us with any thing memorable, $ave
+that (as it $eem'd by rea$on of $ome un-
+ctuou$ne$s of the Liquor) the bubbles
+not ea$ily breaking at the top, and thru$t-
+ing up one another made the intume$cence
+appear much greater then that of common
+Water.
+<p>We likewi$e convey'd Hens Eggs into
+the Receiver, but, after the ex$uction of
+the Air, took them out whole again. That
+which invited us to put them in, was, That
+(as perhaps we mention in other Papers)
+we had among other Experiments of
+cold, made Eggs bur$t, by freezing them
+within doors with Snow and Salt: The
+Ice, into which the aqueous parts of the
+Egge were turned by the cold, $o di$tend-
+<pb n=191>
+ing (probably by rea$on of the numerous
+bubbles wont to be ob$ervable in Ice) the
+outward parts of the Egge, that it u$ually
+crack'd the $hell, though the inner Mem-
+brane that involv'd the $everal Liquors
+of the Egge, becau$e it would $tretch
+and yield, remain d unbroken, And here-
+upon we imagin'd that in our Engine it
+might appear whether or no there were
+any con$iderable Spring, either in any of
+the Liquors, or in any other more $piri-
+tuous $ub$tance included in the Egge.
+<p>We took al$o $ome Spirit of Urine,
+carele$ly enough deflegmed, and put it in-
+to the $ame Gla$s (fir$t carefully $cowr'd
+and clean$'d) wherein we had put the Oyl-
+olive above mention'd: We took al$o an-
+other Gla$s, differing from a Gla$s Egge,
+onely in that its bottom was $lat, and fill'd
+it up to about 2/3 of the Neck (which was
+wider then that of the Egge) with rectifi-
+ed Spirit of Wine.
+<p>We took al$o another Gla$s Egge, and
+having fill'd it with common Water till it
+reach'd to the middle of the Neck, we
+pour'd to it of the $ame Spirit of Wine,
+till it reach'd about an Inch higher.
+<p>The$e three Gla$$es having marks $et
+on them, over again$t the edges of the
+<pb n=192>
+contain'd Liquors were put into the Re-
+ceiver, and that beginning to be evacua-
+ted, the bubbles in all the three Liquors
+began to appear. The mixture of the
+Spirit of Wine and Water di$clo$'d a
+great $tore of bubbles, e$pecially towards
+the top; but $carce afforded us any thing
+worth remem bring. The Spirit of Urine
+appear'd to $well near an Inch and an half
+above the mark; and be$ides that, $ent
+forth $tore of bubbles, which made a
+kinde of froth at the upper part of it. And
+above that $pume there appear'd eight or
+ten great bubbles one above another, in a
+very decent order, each of them con$titu-
+ting, as it were, a Cylinder of about half
+an Inch high, and as broad as the internal
+cavity of the Neck: So that all the upper
+part of the Neck (for the$e bubbles reach'd
+to the top) $eem'd to be divided into al-
+mo$t equal parts, by certain Diaphrag-
+mes, con$i$ting of the coats of the bub-
+bles, who$e edges appear'd like $o many
+Rings $u$pended one above another.
+<p>In the Spirit of Wine there did ari$e a
+great multitude of bubbles, even till
+wearine$s did make us give over the Ex-
+periment. And in the$e bubbles two or
+three things were remarkable; as fir$t,
+<pb n=193>
+That they a$cended with a very notable
+celerity: Next, That being arriv'd at the
+top, they made no $tay there, and yet,
+notwith$tanding the great thinne$s and
+$pitituou$ne$s of the Liquor, did, before
+they broke, lift up the upper $urface of
+it, and for a moment or two form thereof
+a thin film or skin which appear'd protu-
+berant above the re$t of the $uperficies
+like a $mall Hemi$phere. Thirdly, That
+they a$cended $traight up, whereas tho$e
+produc'd at the lower part of the Ve$$el,
+containing the mixture of the Water and
+Spirit of Wine, a$cended with a waver-
+ing or wrigling motion, whereby they
+de$crib'd an indented Line. La$tly, It
+was ob$ervable in the Spirit of Wine (and
+we took notice of the like in the Oyl of
+Turpentine lately mention'd) that not
+onely the bubbles $eem'd to ri$e from cer-
+tain determinate places at the bottom of
+the Gla$s, but that in their a$cen$ion they
+kept an almo$t equal di$tance from each
+other, and follow'd one another in a cer-
+tain order, whereby they $eem'd part of
+$mall Bracelets, con$i$ting of equally lit-
+tle incontiguous Beads: the lower end of
+each Bracelet, being as it were, fa$ten'd to
+a certain point at the bottom of the Gla$s.
+<pb n=194>
+<p>The Air being $paringly let into the
+Receiver, the great bubbles formerly
+mention'd as incumbent upon one ano-
+ther, in that Gla$s that contain'd the Spi-
+rit of Urine, were by orderly degrees
+le$$en'd, till at length they wholly $ub$i-
+ded, notwith$tanding the rece$s of $o ma-
+ny bubbles as broke on the top of the
+Spirit of Urine, during all the time of the
+Experiment; yet it $carcely appear'd at all
+to be $unk below the mark: Nor did the
+mixture of Spirit of Wine and Water
+con$iderably $ub$ide. But that is no-
+thing to what we ob$erv'd in the Spirit
+of Wine, for not onely it con$picuou$ly
+expanded it $elf in the Neck of the
+Ve$$el that contain'd it, notwith$tand-
+ing the largene$s of it; and that the
+bubbles were about to break at the
+top of it almo$t a$$oon as they arriv'd
+there: but upon the re-admi$$ion of
+the external Air, the Spirit of Wine
+retain'd its newly acquired expan$ion.
+And though we let it alone for near
+an hour together, in expectation that it
+might $ub$ide; yet when we took it
+out, we found it $till $well'd between a
+quarter and half an Inch above the
+mark; and although it was not ea$ily
+<pb n=195>
+imaginable how this <I>Ph&aelig;nomenon</I> could
+proceed from any mi$take in trying
+the Experiment, yet the $trangene$$e
+of it invited me to repeat it with fre$h
+Spirit of Wine; which, $welling in the
+Neck as formerly, I left all Night in
+the Receiver, allowing free acce$s to the
+external Air at the Stop-cock, and the
+next day found it $till expanded as be-
+fore, $ave that it $eem'd a little lower:
+which decrement perhaps proceeded from
+the avolation of $ome of the fugitive
+parts of $o volatile a Liquor. And for
+better $atisfaction having taken out the
+Gla$s, and con$ider'd it in the open Air,
+and at a Window, I could not finde that
+there was any remaining Bubbles that
+could occa$ion the per$evering and ad-
+mir'd expan$ion.
+<p>BEing de$irous to di$cover what diffe-
+<MARG><I>Experi-
+ment</I> 25.</MARG>
+rence there might be as to gravity and
+levity, between Air expanded under Wa-
+ter, and it $elfe before $uch expan$ion; we
+took two very $mall Viols, $uch as Chy-
+mical E$$ences (as they call them) are wont
+to be kept in, and of the $ize and $hape ex-
+pre$$ed by the 8<SUP>th</SUP> Figure: into one of the$e
+<pb n=196>
+we put $o much of a certain ponderous
+Mercurial mixture (hapning to be then at
+hand) that the mouth being $topt with a
+little $oft Wax, the Gla$s would ju$t $ink
+in Water and no more; this we let fall to
+the bottom of a wide-mouth'd Cry$tal
+Jar, fill'd with about half a pint of com-
+mon Water, and into the $ame Ve$$el we
+$unk the other E$$ence Gla$s un$topp'd,
+with as much Water in it as was more
+then $ufficient to make it $ub$ide. Both
+the$e $unk with their mouthes downward,
+the former being about three quarters full
+of Air, the latter containing in it a bub-
+ble of Air that was ghe$$'d to be of the
+bigne$s of half a Pea: This done, the
+wide-mouth'd Gla$s was let down into
+the Receiver, and the way of imploy-
+ing the Engine was carefully made u$e
+of.
+<p>The $ucce$s was, That having drawn
+out a pretty quantity of Air, the bubbles
+began to di$clo$e them$elves in the Wa-
+ter, as in the former Experiments; and
+though for a good while after the bubbles
+a$cended in $warms from the lower parts
+of the Water, and ha$tily broke at the
+top; yet we pro$ecuted the Experiment
+$o long without $eeing any effect wrought
+<pb n=197>
+upon the E$$ence: Bottles, that we began
+to di$pair of $eeing either of them ri$e, but
+continuing to ply the Pump, that little
+Gla$s, who$e mouth was open'd, came to
+the top of the Water, being, as it were,
+boy'd up thither by a great number of
+bubbles that had fa$tned them$elves to
+the $ides of it; $wimming thus with the
+mouth downward, we could ea$ily per-
+ceive that the internal Air above men-
+tion'd had much delated it $elf, and there-
+by $eem'd to have contributed to the e-
+merging of the Gla$s, which remain'd
+floating, notwith$tanding the breaking
+and vani$hing of mo$t of the contiguous
+bubbles: being hereby incouraged to per-
+$i$t in pumping, we ob$erved with $ome
+plea$ure, that at each time we turn'd the
+Key, the Air in the little Gla$s did mani-
+fe$tly expand it $elf and thru$t out the wa-
+ter, generally retaining a very protuberant
+$urface where it was contiguous to the re-
+maining Water. And when after divers
+ex$uctions of the Air in the Receiver,
+that in the little Viol $o dilated it $elf as
+to expel almo$t all the Water, it turn'd
+up its mouth towards the $urface of the
+Water in the Jar, and there deliver'd a
+large bubble, and then relap$ed into its
+<pb n=198>
+form&eacute;r floating po$ture: And this Expe-
+riment taught us, among other things,
+that it was a work of more time and la-
+bor then we imagin'd, to exhau$t our En-
+gine as much as it may be exhau$ted: for
+although before the emerging of the $mall
+Viol, we did (as has been touch'd alrea-
+dy) think we had very con$iderably em-
+ptyed the Receiver, becau$e there $eem'd
+to come out but very little or almo$t
+no $en$ible Air at each ex$uction into
+and out of the Cylinder; yet after-
+wards, at each drawing down the Suc-
+ker, the Air included in the Viol did
+manife$tly dilate it $elf, $o long, that
+it did no le$s then nine times turn its
+mouth upwards, and di$charge a bub-
+ble by conjecture about the bigne$s of
+a Pea, after the manner newly recited.
+But as for that Violl which had the
+weight in it, it ro$e not at all. So
+that being not able by quick pumping
+to gain another bubble from the Air
+in the $wimming Gla$s, which proceed-
+ed from $ome $mall leak in the Ve$$el,
+though it held in this Experiment more
+$tanch then was u$ual, we thought fit
+to let in lea$urely the Air from with-
+out, upon who$e admi$$ion that with-
+<pb n=199>
+in the Viol $hrinking into a very nar-
+row compa$s, the Gla$s did, as we expe-
+cted, fall down to the bottom of the
+Jar.
+<p>But being de$irous before we proceed-
+ed to any new. Experiment, to try once
+more whether the little Gla$s that had
+the weight in it might not al$o be rai$'d.
+After we had $uffer'd the Engine to re-
+main clo$'d as it was, for five or $ix
+hours, the Pump was again ply'd with
+$o much ob$tinacy, that not onely a-
+bout the upper part of the Jar there ap-
+pear'd a good number of bubbles (but
+very much $maller then tho$e we $aw
+the fir$t time) but afterwards there
+came from the bottom of the Jar, bub-
+bles about the bigne$s of $mal Peas: which
+the Pump being $till kept going, fol-
+low'd one another, to the number of forty,
+coming from the $topp'd Violl; who$e
+mouth, it $eems, had not been $hut $o
+$trongly and clo$ely, but that the included
+Air, dilating it $elf by its own $pring, made
+it$elf $ome little pa$$age betwixt the Wall
+and the Gla$s, and got away in the$e bub-
+bles; after which, the un$topp'd Gla$s be-
+gan to float again, the Air $hut up in it
+<pb n=200>
+being manife$tly $o dilated as to expel a
+good part of the Water, but not $o much
+as to break quite thorow. And at length,
+when our expectation of it was almo$t ti-
+red out, the heavier of the two Viols be-
+gan to come aloft, and immediately to
+$ub$ide again, which appear'd to be oc-
+ca$ion'd by the Air within it, who$e bulk
+and $pring being weaken'd by the rece$s
+of the forty bubbles before-mention'd, it
+was no longer able, as formerly, to break
+forcibly through the incumbent Water;
+but forming a bubble at the mouth of the
+Gla$s, boyed it up towards the top, and
+there getting away, left it to $ink again
+till the pre$$ure of the Air in the Recei-
+ver being further taken off, the Air in the
+Viol was permitted to expand it $elf fur-
+ther, and to create another bubble, by
+which it was again for a while carried up.
+And it was remarkable, that though after
+having emptyed the Receiver as far as
+well we could, we cea$'d from pumping;
+yet the Ve$$el continuing more $tanch
+then it was wont, this a$cent and fall of
+the Viol was repeated to the ninth time;
+the included Air, by rea$on of the $mal-
+ne$s of the vent at which it mu$t pa$s out,
+being not able to get away otherwi$e then
+<pb n=201>
+little by little; and con$equently, in divers
+$uch parcels as were able to con$titute
+bubbles, each of them big enough to
+rai$e the Viol and keep it aloft until the
+avolation of that bubble. Whereby it
+may appear, that the grand rule in <I>Hy-
+dro$taticks,</I> That a Body will $wim in the
+Water, in ca$e it be lighter then as much
+of that Water that equals it in bulk, will
+hold likewi$e when the pre$$ure of the At-
+mo$phere is in very great mea$ure, if not
+when it is totally taken off from the Li-
+quor and the Body: though it were worth
+inquiring what it is that $o plentifully
+concurs to fill the bubbles made in our
+Experiment by the $o much expanded
+Air, for to $ay with the old Peripatetick
+Schools, That the Air, in Rarefaction,
+may acquire a new extent, without the
+admi$$ion of any new $ub$tance, would
+be an account of the <I>Ph&aelig;nomenon</I> very
+much out of date, and which, I $uppo$e,
+our Modern Naturali$ts would neither
+give, nor acquie$s in.
+<p>I know not whether it may be requi$ite
+to adde, that in this Experiment, as in
+the former, the outward Air being let in
+did $oon precipitate the floating Viol. But
+I think it will not be ami$s to note, that
+<pb n=202>
+(congruou$ly to what hath been above
+recorded of the va$t expan$ion of the Air)
+the Water which in the heavier Viol $uc-
+ceeded in the room of tho$e forty odde, if
+not fifty great bubbles of Air, which at
+$everal times got out of it, amounted but
+to a very incon$iderable bigne$s.
+<p>IT having been ob$erv'd by tho$e that
+<MARG><I>Experi-
+ment</I> 26.</MARG>
+have con$ider'd what belongs to <I>Pendu-
+lums</I> (a Speculation that may, in my
+poor judgement, be highly u$eful to the
+Naturali$ts) that their Vibrations are
+more $lowly made, and that their moti-
+on la$ts le$s in a thicker, then in a thinner
+Medium: We thought it not ami$s to
+try if a <I>Pendulum</I> would $wing fa$ter, or
+continue $winging longer in our Receiver,
+in ca$e of the ex$uction of the Air, then
+otherwi$e. Wherefore we took a couple
+of round and poli$h'd <I>Pendulums</I> of Iron
+or Steel, of equal bigne$s, as near as we
+could get the Artificer to make them, and
+weighing each of them twenty Dragmes,
+wanting as many Grains. One of the$e
+we $u$pended in the cavity of the Recei-
+ver by a very $lender $ilken $tring, of a-
+bout $even Inches and a half in length
+<pb n=203>
+from the cover of the Receiver to which
+it was fa$ten'd. Then (by inclining the
+Engine) we made the <I>Pendulum</I> $wing too
+and fro in it, and de$crib'd as long Arches
+as in the capacity of $o brittle a Ve$$el we
+thought $afe and convenient. And one of
+the A$$i$tants telling the recur$ions of the
+other <I>Pendulum</I> hanging in the free Air,
+by a $tring of about the $ame length, we
+$horten'd and lengthen'd this other <I>Pen-
+dulum,</I> till it appear'd to keep the $ame
+pace in its Vibrations, with that $hut up in
+the Receiver. Then having carefully
+drawn away the Air, we did again $et the
+<I>Pendulum</I> in the Receiver a vibrating;
+and giving the other <I>Pendulum</I> $uch a mo-
+tion as made it de$cribe an Arch, accord-
+ing to ones ghe$s, equal to that of the in-
+cluded <I>Pendulum;</I> we reckon'd, one of
+us, the Recur$ions of that <I>Pendulum</I> which
+was $winging within the Receiver; and
+another of us that which was moving in
+(that which one would think a much more
+re$i$ting <I>medinm</I>) the Air. But once, one
+of us reckon'd near two and twenty Re-
+cur$ions of the included <I>Pendulum,</I> whil$t
+the other reckon'd but twenty of the <I>Pen-
+dulum</I> that vibrated without. And an-
+other time al$o, the former of the$e <I>Pen-</I>
+<pb n=204>
+<I>dula</I> was reckon'd to have made one and
+twenty Recur$ions, wherein the other
+made but twenty: Yet this Experiment
+$eem'd to teach us little, $ave that the dif-
+ference betwixt the motion of $uch a <I>Pen-
+dulum</I> in the common Air, and in one ex-
+ceedingly rarified, is $carce $en$ible in
+Ve$$els no bigger then our Receiver; e-
+$pecially $ince though during this Expe-
+riment it held very well, yet we could
+not $uppo$e it to be altogether devoid of
+Air. We ob$erv'd al$o, that when the
+Receiver was full of Air, the included
+<I>Pendulum</I> continu'd its Recur$ions about
+fifteen minutes (or a quarter of an hour)
+before it left off $winging; and that after
+the ex$uction of the Air, the Vibration
+of the $ame <I>Pendulum</I> (being fre$h put in-
+to motion) appear'd not (by a minutes
+Watch) to la$t $en$ibly longer. So that
+the event of this Experiment being other
+then we expected, $carce afforded us any
+other $atisfaction, then that of our not
+having omitted to try it. And whether
+in ca$e the tryal be made with a <I>Pendulum</I>
+much le$s di$proportionate to the Air then
+Steel is, the event will much better an-
+$wer expectation, experience may be con-
+$ulted.
+<pb n=205>
+<p>THat the Air is the medium whereby
+$ounds are convey'd to the Ear, has
+<MARG><I>Experi-
+ment</I> 27.</MARG>
+been for many Ages, and is yet the com-
+mon Doctrine of the Schools. But this
+Received Opinion has been of late op-
+po$'d by $ome Philo$ophers upon the ac-
+count of an Experiment made by the
+Indu$trious <I>Kircher,</I> and other Learned
+Men, who have (as they a$$ure us) ob-
+$erv'd, That if a Bell, with a Steel Clap-
+per, be $o fa$ten'd to the in$ide of a Tube,
+that upon the making the Experiment <I>De
+Vacuo</I> with that Tube, the Bell remain'd
+$u$pended in the de$erted $pace at the up-
+per end of the Tube: And if al$o a vi-
+gorous Load-$tone be apply'd on the out-
+$ide of the Tube to the Bell, it will at-
+tract the Clapper, which upon the Remo-
+val of the Load-$tone falling back, will
+$trike again$t the oppo$ite $ide of the
+Bell, and thereby produce a very audible
+$ound, whence divers have concluded,
+That 'tis not the Air, but $ome more $ub-
+tle Body that is the medium of $ounds.
+But becau$e we conceiv'd that, to invali-
+date $uch a con$equence from this ingeni-
+ous Experiment (though the mo$t lucife-
+<pb n=206>
+rous, that could well be made without
+$ome $uch Engine as ours) $ome things
+might be $peciou$ly enough alleadg'd; we
+thought fit to make a tryal or two, in or-
+der to the Di$covery of what the Air does
+in conveying of $ounds, re$erving divers
+other Experiments tryable in our Engine
+concerning $ounds, till we can obtain more
+lea$ure to pro$ecute them. Conceiving it
+then the be$t way to make our tryal with
+$uch a noi$e as might not be loud enough
+to make it difficult to di$cern $lighter va-
+riations in it, but rather might be, both
+la$ting, that we might take notice by what
+degrees it decrea$'d; and $o $mall, that
+it could not grow much weaker with-
+out becoming imperceptible. We took
+a Watch, who$e Ca$e we open'd, that
+the contain'd Air might have free egre$s
+into that of the Receiver. And this Watch
+was $u$pended in the cavity of the Ve$$el
+onely by a Pack-thred, as the unlikelie$t
+thing to convey a $ound to the top of the
+Receiver: And then clo$ing up the Ve$-
+$el with melted Plai$ter, we li$ten'd near
+the $ides of it, and plainly enough heard
+the noi$e made by the ballance. Tho$e al-
+$o of us, that watch'd for that Circum-
+$tance, ob$erv'd, that the noi$e $eem'd to
+<pb n=207>
+come directly in a $traight Line from the
+Watch unto the Ear. And it was ob$erva-
+ble to this purpo$e, that we found a mani-
+fe$t di$parity of noi$e, by holding our Ears
+near the $ides of the Receiver, and near the
+Cover of it: which difference $eem'd to
+proceed from that of the Texture of the
+Gla$s, from the $tructure of the cover (and
+of the Cement) through which the $ound
+was propagated from the Watch to the
+Ear. But let us pro$ecute our Experiment.
+The Pump after this being imployd, it
+$eemd that from time to time the $ound
+grew fainter and fainter; $o that when the
+Rec iver was empty'd as much as it u$'d
+to be for the foregoing Experiments, nei-
+ther we, nor $ome $trangers that chanc'd
+to be then in the room, could, by applying
+our Ears to the very $ides, hear any noi$e
+from within; though we could ea$ily per-
+ceive that by the moving of the hand
+which mark'd the $econd minutes, and by
+that of the ballance, that the Watch nei-
+ther $tood $til, nor remarkably varied from
+its wonted motion. And to $atisfie our
+$elvs further that it was indeed the ab$ence
+of the Air about the Watch that hinder'd
+us from hearing it, we let in the external
+Air at the Stop-cock, and then though we
+<pb n=208>
+turn'd the Key and $topt the Valve, yet we
+could plainly hear the noi$e made by the
+ballance, though we held our Ears $ome-
+times at two Foot di$tance from the out-
+$ide of the Receiver. And this Experi-
+ment being reiterated in another place,
+$ucceded after the like manner. Which
+$eems to prove, that whether or no the
+Air be the onely, it is at lea$t, the princi-
+pal medium of Sounds. And by the way
+it is very well worth noting, that in a Ve$-
+$el $o well clo$'d as our Receiver, $o weak
+a pul$e as that of the ballance of a Watch
+$hould propagate a motion to the Ear in a
+Phi$ically $traight Line, notwith$tanding
+the interpo$ition of $o clo$e a Body as
+Gla$s, e$pecially Gla$s of $uch thickne$s
+as that of our Receiver; $ince by this it
+$eems that the air impri$on'd in the Gla$s,
+mu$t, by the motion of the ballance, be
+made to beat again$t the concave part of
+the Receiver, $trongly enough to make
+its convex part beat upon the contiguous
+Air, and $o propagate the motion to the
+Li$tners ears. I know this cannot but
+$eem $trange to tho$e, who, with an emi-
+nent Modern Philo$opher, will not allow
+that a Sound, made in the cavity of a
+Room, or other place $o clo$'d, that there
+<pb n=209>
+is no intercour$e betwixt the external and
+internal Air, can be heard by tho$e with-
+out, unle$s the $ounding Body do imme-
+diately $trike again$t $ome part of the in-
+clo$ing Body. But not having now time
+to handle Controver$ies, we $hall onely
+annex, That after the foregoing Experi-
+ment, we took a Bell of about two Inches
+in Diameter at the bottom, which was
+$upported in the mid$t of the cavity of
+the Receiver by a bent $tick, which by
+rea$on of its Spring pre$$'d with its two
+ends again$t the oppo$ite parts of the in-
+$ide of the Ve$$el: in which, when it was
+clo$'d up, we ob$erv'd that the Bell $eem'd
+to $ound more dead then it did when ju$t
+before it $ounded in the open Air. And
+yet, when afterwards we had as formerly
+emptyed the Receiver, we could not di$-
+cern any con$iderable change (for $ome
+$aid they ob$erv'd a $mall one) in the loud-
+ne$s of the $ound, whereby it $eem'd that
+though the Air be the principal medium
+of $ound, yet either a more $ubtle mat-
+ter may be al$o a medium of it, or el$e an
+ambient Body that contains but very
+few particles of Air, in compari$on of
+tho$e it is ea$ily capable of, is $ufficient
+for that purpo$e. And this, among o-
+<pb n=210>
+ther things, invited us to con$ider, whether
+in the above-mention'd Experiment made
+with the Bell and the Load-$tone, there
+might not in the de$erted part of the Tube
+remain Air enough to produce a $ound:
+$ince the Tubes for the Experiment <I>De
+Vacuo</I> (not to mention the u$ual thin-
+ne$s of the Gla$s) being $eldom made
+greater then is requi$ite, a little Air might
+bear a not incon$iderable proportion to
+the de$erted $pace. And that al$o, in the
+Experiment <I>De Vacuo,</I> as it is wont to be
+made, there is generally $ome little Air
+that gets in from without, or at lea$t $tore
+of bubbles that ari$e from the Body of
+the Quick-$ilver, or other Liquor it $elf,
+Ob$ervations heedfully made have fre-
+quently informed us: And it may al$o
+appear, by what has been formerly deli-
+vered concerning the <I>Torricellian</I> Experi-
+ment.
+<p>On the occa$ion of this Experiment
+concerning $ounds, we may adde in this
+place, That when we try'd the Experiment
+formerly mention'd, of firing Gun-pow-
+der with a Pi$tol in our evacuated Recei-
+ver, the noi$e made by the $triking of the
+Flint again$t the Steel, was exceeding
+languid in compari$on of what it would
+<pb n=211>
+have been in the open Air. And on di-
+vers other occa$ions it appear'd that the
+$ounds created within our exhau$ted
+Gla$s, if they were not lo$t before they
+reach'd the Ear, $eem'd at lea$t to arrive
+there very much weaken'd. We intended
+to try whether or no the Wire-$tring of an
+In$trument $hut up into our Receiver,
+would, when the ambient Air was $uck'd
+out, at all tremble, if in another In$trument
+held clo$e to it, but without the Receiver
+a $tring tun'd (as Mu$icians $peak, how
+properly I now examine not) to an Uni$on
+with it, were briskly toucht, and $et a Vi-
+brating. This, I $ay, we purpo$'d to try
+to $ee how the motion made in the Air
+without, would be propagated through the
+cavity of our evacuated Receiver. But
+when the In$trument wherewith the tryal
+was to be made came to be imploy'd, it
+prov'd too big to go into the Pneumatical
+Ve$$el, and we have not now the conveni-
+ency to have a fitter made.
+<p>We thought likewi$e to convey into
+the Receiver a long and $lender pair of
+Bellows, made after the fa$hion of tho$e
+u$ually employ'd to blow Organs, and fur-
+ni$h'd with a $mall Mu$ical in$tead of an
+<pb n=212>
+ordinary Pipe. For we hop'd, that by
+means of a $tring fa$tned to the upper
+part of the Bellows, and to the moveable
+$topple that makes a part of the Cover
+of our Receiver, we $hould, by frequent-
+ly turning round that $topple, and the an-
+nexed $tring, after the manner already
+often recited, be able to lift up and di$tend
+the Bellows; and by the help of a com-
+petent weight fa$ten'd to the $ame upper
+part of the Bellows, we $hould likewi$e
+be able, at plea$ure, to compre$s them:
+and by con$equence, try whether that
+$ubtler matter then Air (which, accord-
+ing to tho$e that deny a <I>Vacuum,</I> mu$t be
+$uppo$'d to fill the exhau$ted Receiver)
+would be able to produce a $ound in the
+Mu$ical Pipe; or in a Pipe like that of or-
+dinary Bellows, to beget a Wind capable
+to turn or $et a moving $ome very light
+matter, either $hap'd like the Sails of a
+Wind-Mill, or of $ome other conveni-
+ent form, and expo$'d to its Orifice. This
+Experiment, I $ay, we thought to make,
+but have not yet actually made it for want
+of an Artificer to make us $uch a pair of
+Bellows as it requires.
+<p>We had thoughts al$o of trying whe-
+ther or no, as Sounds made by Bodies in
+<pb n=213>
+our Receiver become much more languid
+then ordinary, by rea$on of the want of
+Air, $o they would grow $tronger, in ca$e
+there were an unu$ual quantity of Air
+crouded and $hut up in the $ame Ve$$el,
+which may be done (though not without
+$ome difficulty) by the help of the Pump,
+provided the Cover and Stopple be $o
+firmly fa$ten'd (by binding and Cement,
+or otherwi$e) to the Gla$s; and to each
+other, that there be no danger of the
+conden$'d Airs blowing of either of them
+away, or its breaking through the jun-
+ctures. The$e thoughts, My Lord, as I
+was $aying, we entertain'd; but for want
+of lea$ure, as, of as good Receivers as
+ours, to $ub$titute in its place, in ca$e we
+$hould break it before we learn'd the skill
+of condencing the Air in it, we dur$t not
+put them in practice: Yet, on this occa-
+$ion, give me leave to adverti$e Your
+Lord$hip once for all, That though for
+the rea$ons newly intimated, we have,
+Onely in the $eventeenth Experiment,
+taken notice, that by the help of our En-
+gine the Air may be conden$'d as well as
+rarified; yet there are divers other of our
+Experiments, who$e <I>Ph&aelig;nomena</I> it were
+<pb n=214>
+worth while to try to vary, by means of
+the compre$$ion of the Air.
+<p>WE taught, among divers other
+<MARG><I>Experi-
+ment</I> 28.</MARG>
+things, when we di$cour$'d of our
+fir$t Experiment, That the Air $hut up in
+our Receiver, pre$$eth as $trongly upon
+the Bodies $hut up with it, as if they
+were expo$'d to the pre$$ure of the whole
+Atmo$phere. That this was not incon-
+$iderately propounded, we hope Your
+Lord$hip has gather'd from divers of the
+things already recited: But yet perhaps it
+will not be ami$s to $ubjoyn, by way of
+further confirmation of the $ame truth, the
+following Experiment, which $hould have
+accompanied the 20<SUP>th</SUP>, but the Paper where
+in the one was written chanc'd not to beat
+hand, when the other was $ent away.
+<p>We convey'd into the Receiver a new
+Gla$s Viol, capable of holding about 6 or
+7 ounces of Water, into which we had
+before put 2 or 3 Spoon-fulls of that Li-
+quor, and $topt it clo$e with a fit Cork.
+The Pneumatical Ve$$el being empty'd,
+there appear'd not any change in the in-
+clo$'d Water, the Air impri$on'd with it,
+not having the force to blow out the $top-
+<pb n=215>
+ple, which event, though it were no other
+then we expected, was differing from what
+we de$ir'd. For we would gladly have $een
+what change would have appear'd in the
+Water upon the Bottles being $uddenly
+un$topp'd, in a place where the ambient
+Body was $o differing from our common
+Air. Wherefore we did again put in the
+Viol, but le$s $trongly clo$'d then for-
+merly, though as $trongly $topt as $eem'd
+requi$ite on ordinary occa$ions: But when
+the Air was pump'd out of the Receiver,
+that within the Viol did quickly, as we
+expected, find or make it $elf little pa$$a-
+ges to get out at: as we argu'd, from this,
+That whereas when the Viol was put in
+the time before, the Water remain'd all
+the while perfectly free from bubbles; at
+this time the bottom of the Gla$s ap-
+pear'd all cover'd with them, and they,
+upon the regre$s of the excluded Air into
+the Receiver, did pre$ently flag and $hrink
+up.
+<p>From the$e tryals it $eem'd deducible
+enough, that whil'$t the Viol continu'd
+to be well $topt, the included Water
+did, from the Air, $hut up with it,
+$u$tain a pre$$ure equal to that of the
+Atmo$phere; $ince till the Air could get
+<pb n=216>
+out of the Gla$s, there appear'd no bub-
+bles in the Water, notwith$tanding the
+want of pre$$ure in the ambient Body.
+<p>But to be $ure to reach the chief end of
+our Experiment, we made u$e of this o-
+ther expedient: We cau$'d a convenient
+quantity of Water to be put, and Her-
+metically $hut up into a Gla$s Egge, to
+who$e long Neck (which was purpo$ely
+made of an unequal thickne$s) was fa-
+$ten'd to one end of a $tring, who$e o-
+ther end was ty'd to the Cover of our
+Receiver, after the manner el$ewhere men-
+tion'd already: Then the Egge being
+convey'd into the Pneumatical Ve$$el,
+and that being evacuated, we did, by
+turning the bra$s Stopple formerly de-
+$crib'd among$t the parts of our En-
+gine, $o $horten the $tring as to break the
+Gla$s; whereby liberty being given to
+the Air impri$on'd in the Egge, to pa$s
+into the capacity of the Receiver, the $ud-
+den rece$s of the Air made the bubbles in
+a trice appear $o numerous, and a$cend
+$o $wiftly in the Water, that their motion
+look'd like that of a violent $hower of
+Rain; $ave that the bubbles did not, like
+the drops of Rain, tend downwards, but
+upwards, which made me re$emble this
+<pb n=217>
+<I>Ph&aelig;nomenon</I> to what I have $een happen
+in the di$$olution of Seed-Pearl in $ome
+acid <I>Men$truum,</I> in which, if a good quan-
+tity of the little Pearls be ca$t whole, they
+will at fir$t, if the <I>Men$truum</I> be $harp e-
+nough, be carryed in $warms from the
+bottom to the top of the Liquor. We
+will adde, that without $ealing up the
+Gla$s, this Experiment may be try'd in
+one of our $malle$t Receivers, for there
+the ex$uction of the ambient Air may be
+perform'd $o nimbly, that immediately
+the bubbles lurking in the Water are al-
+low'd to di$play them$elves, and a$cend
+in throngs; in$omuch, as having in $uch
+a Receiver try'd the Experiment with
+Wine (as a more $pirituous Liquor) in-
+$tead of Water, the Red-Wine appear'd
+all cover'd, with a copious, but vani$hing
+white Froth, almo$t as if a Ve$$el full of
+bottl'd drink had been unwarily open'd.
+<p>IT may not a little conduce to the clear-
+<MARG><I>Experi-
+ment</I> 29</MARG>
+er explication of divers Points in the
+Doctrine of Meteors, and perhaps of
+$ome other Phy$iological difficulties, to
+di$cover what the Air does to the motion
+of tho$e Steams or Exhalations that a$-
+<pb n=218>
+cend into it, namely, Whether they mount
+upwards by vertue of any $uch <I>po$itive le-
+vity</I> (as $ome Peripateticks $peak) ac-
+quir'd together with their A&euml;rial nature,
+as inables them to pierce through part of
+the Atmo$phere, and over-come its re-
+$i$tance. Or el$e, whether the$e $teams
+being once rai$'d above the Earth by their
+agitation, have their a$cent and $u$tenta-
+tion aloft, rather promoted then hindred
+by the Air: as the inferior parts of that,
+being thicker and heavier then the $upe-
+rior, the $teams can more ea$ily continue
+for a while their agitation upwards then
+downwards; And afterwards are by the
+$ame fluidity and thickne$s of the Air,
+carried to and fro in it, and kept from re-
+lap$ing to the Earth, as in the Sea water
+the $aline parts are kept from $ub$iding by
+tho$e aqueous ones wherewith they are
+a$$ociated.
+<p>We hop'd to illu$trate this matter, by
+ob$erving the motion of the $moke, pro-
+ceeding from kindled or flaming Bodies in
+our exhau$ted Receiver. But as we for-
+merly noted, upon the ex$uction of the
+Air, the $moking of tho$e Bodies pre-
+$ently cea$'d. We had thoughts al$o of
+conveying into our Pneumatical Gla$s a
+<pb n=219>
+hot Iron, with $ome Body ea$ie to be
+di$$ipated into $moke $et upon it, but con-
+$ider'd, that neither was that way free
+from inconveniencies; e$pecially this, that
+the hot Body would make the Impri$on'd
+Air circulate within the Receiver, and
+con$equently make it que$tionable whe-
+ther the a$cent of the $teams would not
+be due to the new and acquired motion of
+the Air.
+<p>Wherefore I bethought my $elf of an-
+other way to $atisfie in $ome mea$ure my
+curio$ity, to wit, by means of a certain
+Liquor, which I call'd to minde that $ome
+years ago I had (for a de$ign that belongs
+not to our pre$ent purpo$e) prepar'd;
+which, I $uppo$e, I $hew'd Your Lord-
+$hip, and which had the luck to be ta-
+ken notice of by divers very Ingenious
+and Famous Men. For this Liquor,
+though mo$t of its Ingredients be Metals,
+and all of them ponderous enough, is yet
+of that nature, that whil$t the Viol where-
+in it is kept is $topt (how $light a Cover
+$oever) both the Liquor and the Gla$s
+are tran$parent; and $o is that upper half
+of the Gla$s to which the Liquor reaches
+not. But a$$oon as ever the $topple is ta-
+ken out, and full acce$s is given to the ex-
+<pb n=220>
+ternal Air, both the inward part of the
+Cork, and the Liquor it $elf, do pre$ent-
+ly $end upwards, and $catter abroad a
+fume as thick and white, as if there were
+a quantity of Alabla$ter-du$t thrown up
+into the Air: And this $moking of the
+Liquor la$ts till my unwillingne$s to wa$te
+it, invites me $top it again; and then the
+a$cen$ion of the fumes $uddenly cea$es, till
+the Viol be again un$top'd.
+<p>This fuming Liquor then I thought
+would much conduce to the di$covery I
+de$ir'd to make, $ince it $av'd me the need
+of conveying any hot Body with it into
+the Receiver, and would not darken it
+with fumes before the time. Wherefore
+having ty'd to the Viol a great weight of
+Lead, to keep it from being lifted up by
+the drawing out of the Cork; and having
+ty'd to the $topple one end of a $tring, of
+which the other end was made fa$t to the
+Cover of the Pneumatical Gla$s, the Li-
+quor was carefully clo$'d up after the
+wonted manner; then the Air being dili-
+gently pump'd out, the Viol was un$topt
+in the empty'd Receiver: and though
+immediately, npon the drawing out of the
+Cork, there appear'd to be as it were
+thrown up $ome white fumes, which
+<pb n=221>
+$eem'd to proceed from the Air before
+impri$on'd in the Viol, and diffu$ing it
+$elf $uddenly into the capicity of the
+Receiver. Yet we afterward ob$erv'd,
+as we expected, That the fumes did not
+mount and di$per$e them$elves as they
+u$e to do in the open Air, but that, when
+by rea$on of the agitation of the Cor-
+pu$cles of the Liquor, which could not
+continue their motion in $o narrow a
+$pace as the Viol afforded them, and were
+therefore reduc'd to thru$t one another
+out of it; when, I $ay, by the$e a$$i-
+$tances the fumes were a$cended to the lip
+of the Viol, they mounted no higher,
+but ran down along the out-$ide of the
+Viol to the bottom of it; and thence
+along, a long and inclining piece of Lead,
+on which the Viol re$ted, like a little
+Stream (not very much bigger then a
+Swans Quill) who$e nature it $eemd to e-
+mulate $o well, that it quitted not the Viol
+till it was come to the bottom of it, and
+then for$ook it in $uch a manner as a
+$tream of Water of the $ame bigne$s
+would have done. And this $tream la$ted
+a pretty while, and would probably have
+la$ted longer, but that being loath to wa$te
+my Liquor, I let in at the Stop-cock a
+<pb n=222>
+pretty deal of the external Air; notwith-
+$tanding which, finding after a while the
+$tream did run afre$h; though, as it $eem'd,
+not altogether $o copious as before: I let
+as much more Air, as would, come in, and
+found ($omewhat to my wonder) that
+though the $tream formerly mention'd
+di$-appear'd, yet there appear'd not any
+white fumes to ari$e, either from the Cork,
+or out of the Viol it $elf, no not when
+the Cover was remov'd from the Recei-
+ver; though not onely after a while there
+a$cended white Fumes from the Receiver:
+but having forthwith taken out the Viol
+into the open Air, it emitted white ex-
+halations as before; and having pre$ently
+after un$top'd it in an open Window, we
+found both it and the Cork immediatly
+to $end forth a yet much more plentiful
+$moak. Though it be now divers years
+$ince this Numerical Liquor was prepa-
+red, after the manner mention'd either
+by <I>Carneiades</I> or <I>Eleutherius</I> (for I do not
+well remember which) in tho$e Dialogues
+concerning Heat and Flame that have a-
+bove been mention'd.
+<p>More Circum$tances concerning the$e
+Fumes we might have ob$erv'd, had we
+not been deterr'd by an Indi$po$ition in
+<pb n=223>
+point of health, from having much to do
+with $teams of $o dangerous a nature, as by
+that of the Ingredients of this Liquor
+the$e $eem likely to be of.
+<p>The Reflections that may be made up-
+on this Experiment, we have not now the
+lea$ure to pro$ecute, and therefore $hall
+content our $elves to recommend the $e-
+veral Circum$tances of it to Your Lord-
+$hips $erious con$ideration; and to take
+notice <I>(en pa$$ant)</I> that $teams in an am-
+bient Body, or a medium thinner then
+them$elves, may both tend downwards,
+and otherwi$e emulate the nature of a
+Liquor; which I therefore point at, that
+it may appear the le$s $trange, if we $ome-
+times $peak of the Atmo$phere as of a
+kinde of Liquor, in compari$on of that
+more thin and $ubtle Cele$tial Matter that
+$urrounds it.
+<p>And though it might perchance $uf-
+fice to have on this occa$ion intima-
+ted thus much; yet, le$t this way
+of $peaking of the Atmo$phere $hould
+be thought too bold and extra-
+vagant, I am content to borrow an
+Experiment of the Di$cour$e former-
+<pb n=224>
+ly mention'd (touching fluidity and firm-
+ne$s) and $ubjoyn it here with alterations
+$uitable to the contrivance of our Engine;
+and this the rather, becau$e I hope it may
+conduce to the di$covery of the nature of
+the Atmo$phere: for which rea$on it
+might have been annext to what has been
+noted either upon the fir$t, or eighteenth
+Experiment, but that when they were
+written and $ent away, it came not into
+my minde. The Experiment then as we
+try'd in our Engine, was as follows.
+<p>WE took one of the $mall Receivers,
+<MARG><I>Experi-
+ment</I> 30.</MARG>
+often mention'd already, and into it
+we convey'd a piece of well lighted Match;
+and letting it remain there till it had fill'd
+the Receiver with $moak, we took it out
+and ha$tily clo$'d again the Receiver, that
+the $moak might not get away. Then
+$taying awhile to let the$e fumes lei$urely
+$ub$ide, we found, as we expected, that
+after $ome time they $etled them$elves in
+the lower half of the Receiver, in a dark-
+i$h Body, leaving the upper half of the
+Receiver tran$parent, and as to $ight, full
+of nought but clear Air. Now to mani-
+fe$t that this $moak thus $etled emulated
+<pb n=225>
+a Liquor, we inclin'd the Engine that con-
+tain'd it, $ometimes to one $ide, and $ome-
+times to the other; and ob$erv'd the
+$moak to keep its $urface almo$t Hori-
+zontal, notwith$tanding the $tooping of
+the Ve$$el that held it, as Water or an-
+other Liquor would in the like ca$e have
+done. And if by a quicker rocking of the
+Engine the $moke were more $wiftly $ha-
+ken, it would, like Water, either Vibrate
+to and fro from one $ide to the other of
+the Gla$s, or el$e have its $urface manife$t-
+ly curll'd with Waves, but pre$erve its
+$elf in an intire and di$tinct Body from the
+incumbent Air; and being permitted to
+re$t awhile, would $oon recover its for-
+mer $mooth and level <I>$uperficies:</I> If al$o
+the Key were turn'd and the Valve un-
+$topp'd, $o that there was a free, though
+but a narrow pa$$age open'd betwixt the
+external Air and the cavity of the Recei-
+ver, then would $ome of this $moak fall
+down, as it were, in a $tream into the $ub-
+jacent Cylinder, and a proportionate
+quantity of the outward Air, would ma-
+nife$tly a$cend through it into the incum-
+bent Air, much after the $ame manner as
+if you invert a Viol with a long Neck, and
+well fill'd with Red-Wine, into a Gla$s
+<pb n=226>
+full of fair water, you $hall $ee the Water
+and Wine by degrees mingle with one an-
+other; the one falling downe as it were in
+little colour'd $treames, and the other a$-
+cending into its room in the like curled
+$treames, $ometimes preceded by round
+parcels of water, which, by rea$on of their
+tran$parency, looke almo$t like bubbles.
+The other circum$tances of this Experi-
+ment, belonging not all of them to our
+pre$ent purpo$e, we $hall content our
+$elves with taking notice of one which
+$eemes the mo$t important, and may illu-
+$trate and confirme $ome things former-
+ly delivered. And it was, That if, when
+the <I>$uperficies</I> of our Smoke lay $mooth
+and horizontal, a hot iron were held near
+the our $ide of the Receiver, the Neigh-
+bouring part of the included fumes (for
+the re$t did not very much alter their for-
+mer <I>$uperficies</I>) being rarified by the heat,
+would readily a$cend in a large Pillar of
+$moke to the very top of the Receiver,
+yet without $eeming to loo$e a di$tinct
+<I>$uperficies,</I> or to be confounded with Air;
+below which, upon the rece$s of the ad-
+ventitious heat that by agitating it im-
+pell'd it upward, it would againe $ub-
+$ide.
+<pb n=227>
+<p>All which being added to the late Ex-
+periment of the $moking Liquor, and
+to what may be from that which has been
+el$ewhere $ayd, gather'd to the $ame pur-
+po$e, will, I hope, keep it at lea$t from ap-
+pearing ab$ur'd: If $ince we $ee that there
+is $o great an inequality in the den$ity and
+weight of Liquors, that water is neere 14
+times thinner or lighter than Quick-$ilver
+of the $ame bulk, and well dephlegm'd;
+Spirit of Wine yet much lighter than wa-
+ter; we venter to $peak $ometimes of the
+Atmo$phere, as if it were a peculiar kind
+of thin and halituous Liquor (if I may $o
+call it) much lighter than Spirit of Wine.
+<p>To the$e things I know not whether it
+will be requi$ite to add, that as we late-
+ly took notice of con$picuous waves that
+appear'd upon the <I>$uperficies</I> of our agi-
+tated $moke. So $ome $uch thing may
+not ab$urdly be conjectur'd to happen
+on the <I>$uperficies</I> of the Atmo$phere,
+by tho$e $trange ruggedne$$es that ap-
+peare (e$pecially in the Spring and Fall,
+when exhalations and vapours are wont to
+a$cend mo$t plentifully) upon the Limb
+or Edge of the Ri$ing and Setting Sun. I
+$peake thus diffidently upon this occa$ion
+becau$e I know that by the Fluctuation or
+<pb n=228>
+Boyling of the Sun's own <I>$uperficies</I> di-
+ver$e eminent Mathematicians have plau-
+$ibly enough (but how truly I leave
+your Lord$hip to Judge) endeavour'd to
+give an Account of it. But if we will joine
+with tho$e that have a$crib'd of late this
+<I>Ph&aelig;nomenon</I> to the Refraction the Sun-
+Beames fuffer in our vapid Air; we may,
+as hath been intimated, promote their Do-
+ctrin by deducing from it, that probably
+the $urface Atmo$phere is oftentimes (if
+not alwayes) exceedingly curl'd or wav'd.
+And certainly it is $omewhat wonderfull
+as well as very plea$ant to behold, how,
+to him that looks upon the $etting Sun
+through a long &amp; excellent Tele$cope,
+there will not only appeare $trange ine-
+qualities in the edge of it (in$omuch that
+I have often $een it more indented than a
+Saw) but tho$e inequalities will vani$h in
+one place and pre$ently appeare in ano-
+ther, and $eem perfectly to move like
+waves $ucceeding and de$troying one an-
+other; $ave that their Motion oftentimes
+$eemes to be quicke$t as if in that va$t $ea
+they were carried on by a current, or at
+lea$t by a tide. And this (as we el$e
+where note) appear's to the eye not on-
+ly when it looks directly through the te-
+<pb n=229>
+le$cope upon the $unne; but al$o when a
+large and well defin'd image of the $unne
+is by the $ame tele$cope brought into a
+roome and ca$t upon a $heet of white pa-
+per. But to in$i$t on this were to digre$s:
+and therefore I will proceed to experi-
+ments of another kind.
+<p>IT has been admir'd by very ingenious
+<MARG><I>Experi-
+ment</I> 31,</MARG>
+Men, that if the exqui$itly poli$h'd
+$urfaces of two flat peeces of marble be $o
+congruous to each other that from their
+mutuall application there will re$ult an
+immediate contact, they will $tick $o fa$t
+together, that he that lifts up the upper-
+mo$t, $hall, if the undermo$t be not ex-
+ceeding heavy, lift up that too, and $u$-
+taine it aloft in the free aire. A proba-
+ble cau$e of this $o clo$e adhe$ion we have
+el$ewhere endeavour'd to deduce from the
+unequall pre$$ure of the Air upon the un-
+dermo$t $tone; For the lower <I>$uperficies</I>
+of that $tone being freely expos'd to the
+Air is pre$$'d upon by it, whereas the up-
+permo$t $urface, being contiguous to the
+$uperiour $tone, is thereby defended from
+the pre$$ure of the Air which con$equent-
+ly pre$$ing the lower $tone again$t the up-
+<pb n=230>
+per, hinders it from falling, as we have
+el$ewhere more fully declar'd. Upon
+the$e grounds we conjectur'd that in ca$e
+we could procure two marbles exactly
+ground to one another; and in ca$e we
+could al$o $ufficiently evacuate our Re-
+ceiver, the lower $tone would, for want
+of the wonted and $u$taining pre$$ure of
+the Air, fall from the upper. But the
+further tryal of this Experiment we mu$t,
+unle$s your Lord$hip think it worth Your
+making at <I>Paris,</I> put off till a fitter
+opportunity. For where we now are, we
+cannot procure marbles $o exactly ground,
+that they will $u$taine one another in the
+Air, above a minute or two, which is a
+much $horter time than the emptying of
+our Receiver requires. We did indeed
+try to make our marbles $tick clo$e to-
+gether by moi$tening their polli$hed $ur-
+faces with rectifi'd $pirit of Wine, in re-
+gard that Liquor by its $udden avolation
+from marble, if powr'd thereon, without
+leaving it moi$t or le$s $mooth, $eem'd
+unable to $u$taine them together after the
+manner of a glutinous body, and yet
+$eem'd $ufficient to exclude and keep out
+the Air. But this we try'd to little pur-
+po$e, for having convey'd into the Recei-
+<pb n=231>
+ver two black $quare marbles (the one of
+two inches and a third in length or
+breadth, and $omewhat more than halfe
+an inch in thickne$s: The other of the $ame
+extent, but not much above halfe $o
+thick) fa$ten'd together by the interven-
+tion of pure Spirit of Wine; and having
+$u$pended the thicker by a $tring from the
+cover, we found not that the ex$uction of
+the ambient Air would $eparate them,
+though a weight amounting to four oun-
+ces were fa$ten'd to the lowermo$t mar-
+ble to facilitate it's falling off.
+<p>I would gladly have the Experiment
+try'd with marble $o well polli$h't as to
+need no Liquor what$oever to make them
+cohere, and in a Ve$$el out of which the
+Air may be more perfectly drawn than it
+was out of ours. But in the mean time
+though we will not determin whether the
+Spirit of wine did contribute to the $trong
+cohe$ion of the$e $tones, otherwi$e than
+by keeping ev'n the $ubtl'$t parts of the
+Air from getting in between them, yet it
+$eemed that the not falling downe of the
+lowermo$t marble might without impro-
+bability be a$crib'd to the pre$$ure of the
+Air remaining in the Receiver; which as
+we formerly noted having been able
+<pb n=232>
+to keep a Cylinder of water of above
+a Foot in height from falling to the bot-
+tom of the Tube, may well enough be
+$uppo$'d capable of keeping $o broad a flat
+Marble from de$cending. And though this
+may $eem a $trange proof of the $trength of
+the $pring of Air, ev'n when rarified, yet it
+will $carce $eem incredible to him that has
+ob$erv'd how exceeding $trong a cohe$ion
+may be made betwixt broad Bodies, one-
+ly by their immediate touching one ano-
+ther. A notable in$tance of which, I
+have met with in this $hort Narrative of
+<MARG><I>P. Nic.
+Zucchius
+opal Schot:
+part</I> 1.
+<*></MARG>
+the Learned <I>Zucchius. Fuveni</I> ($ays he)
+<I>lacertorum $uorum robur: jactanti propo-
+$ita $emel e$t lamina &aelig;rea, per an$am in
+medio extantem apprehen$am elevanda &egrave;
+tabula marmorea, cui optime congruebat:
+qui primo tanquam rem ludicr am puero
+committendam contemp$it: tum in$tanti-
+bus amicis manum utr&aacute;mque admovens,
+cum luctatus diu h&aelig;rentem non removi$$et,
+excu$avit impotentiam, objecta perigrini
+&amp; potenti$simi glutinis interpo$itione, quo
+forti$sime copulante nequiret divelli; do-
+nec vidit ab alio per tabulam facilim&egrave; lami-
+nam deduci, &amp; ad extrema product am, &amp;
+actam in tran$ver$um in&agrave;e deportari.</I> But
+that we may learn from our own Engine,
+<pb n=233>
+that two Bodies, though they touch each
+other but in a $mall part of their $urfaces,
+may be made to cohere very $trongly,
+onely by this, That the Air pre$$es much
+more forcibly upon the inferior $uperfi-
+cies of the lowermo$t Body, then upon
+the upper $urface of the $ame: We will
+hereunto annex the following Experi-
+ment, though out of the order wherein
+they were made.
+<MARG><I>Experi-
+ment</I> 32.</MARG>
+<p>I remember I have, in a Di$cour$e con-
+cerning Fluidity and Firmne$s, made
+mention of my having, by the ex$uction
+of the Air out of a Gla$s Ve$$el, made
+that Ve$$el take up, or $uck up (to $peak in
+the common Language) a Body weighing
+divers Ounces; but our Engine affording
+us the opportunity of making con$ider-
+abler Experiments of that kinde, We
+thought fit to make a further tryal of the
+force of the Atmo$phere's pre$$ure up-
+wards, after the following manner.
+<p>The Receiver having been exqui$itely
+clo$'d, as we have often taught already,
+and the Air being in a good mea$ure drawn
+out of it, it was remov'd from off the
+Pump: and to the lower Branch of the
+<pb n=234>
+Stop-cock, there was $peedily apply'd a
+tapering Valve of bra$s, $uch as is de$crib'd
+in the 9<SUP>th</SUP> fig: made fit to go with its nar-
+rower end into the cavity of the branch,
+and to fill the orifice of that cavity with
+its broader part. And that the Air might
+not get in at the litle intervals, left here
+and there between the convex $urface of
+the $topple and the internall edge of the
+branch, tho$e intervals were $top't with
+a little Diachylon. And to the doore,
+or, (if you plea$e) that part of the Valve
+which was to move to and fro, and in
+this Experiment hung perpendicular to
+the Horizon, there was, at a button of
+bra$s belonging to the Valve fa$ten'd a
+broad $cale wherein weights were to be
+put. This done the key of the Stop-cock
+was turn'd, and the externall Air beating
+like a forcible $treame upon the Valve
+to get in there, it did $uddenly both $hut
+the Valve and keep it $hut $o $trongly,
+that we had time to ca$t in diver$e weights
+one after another into the Scale; till at
+length the weight overpowering the pre$-
+$ure of the Atmo$phere, drew downe the
+Valve by the $tringes that ty'd the Scale
+to it, and gave liberty to the outward Air
+to ru$h into the Receiver. Though a-
+<pb n=235>
+nother time, when the Valve had but lit-
+tle weight hanging at it, being, by I know
+not what accident, drawn down beneath its
+former place, it was by the impetuous
+current of the outward Air $uddenly im-
+pell'd up into it again, and kept there.
+But in the former Experiment it is re-
+markable, That though the Receiver were
+not well exhau$ted, and though it leak'd
+whil'$t the re$t of the Experiment was in
+pro$ecution, and though the Valve
+whereon the Cylinder of the Atmo$phere
+could pre$s, were not above an Inch and
+a half in Diameter, yet the weight kept
+up by $uction, or rather $upported by the
+Air, namely the Valve, the Seal and
+what was ca$t into it, being $ent to be
+weigh'd, amounted to about ten of our
+common Pounds, con$i$ting of $ixteen
+Ounces apiece: So that we doubted not
+but that, had the Experiment been made
+with favorable Circum$tances, the Air
+endeavoring to pre$s in at the Orifice of
+the Stop-cock, would have kept a very
+much greater weight from falling out of
+it; I $ay the Air, becau$e we found, by
+tryal purpo$ely made, that neither the
+imperfect contact of the Valve and the
+Stop-cock, nor the Diachylon that was
+<pb n=236>
+employ'd to fill up the little Crannies left
+betwixt them, were con$iderable in this
+Experiment; by which may among other
+things appear, that I did not without
+cau$e in the above-nam'd Di$cour$e touch-
+ing Fluidity and Firmne$s, a$cribe a great
+force, ev'n to $uch Pillars of Air as may
+be $uppo$'d to begin at the top of the
+Atmo$phere, and recoyling from the
+ground to terminate on the Bodies on
+which they pre$s: $ince in the pre$ent Ex-
+periment $uch a weight was $upported by
+$o $lender a Cylinder of Air, rebounding
+from the Earth to the Valve whereon it
+did bear.
+<p>BUt in regard we have not yet been
+<MARG><I>Experi-
+ment</I> 33.</MARG>
+able to empty $o great a Ve$$el as our
+Receiver, $o well as we can the Cylinder
+it $elf; our Pump alone may afford us a
+nobler in$tance of the fotce of the Air we
+live in, in$omuch, that by help of this
+part of our Engine, we may give a pretty
+near ghe$s at the $trength of the Atmo-
+$phere, computed as a weight. And the
+way may be this; Fir$t, the Sucker be-
+ing brought to move ea$ily up and down
+the Cylinder, is to be impell'd to the top
+<pb n=237>
+of it: Then the Receiver mu$t be taken
+off from the Pump, that the upper Ori-
+fice of the Cylinder remaining open, the
+Air may freely $ucceed the Sucker, and
+therefore readily yield to its motion
+downward. This done, there mu$t be
+fa$ten'd to one of the Iron Teeth of the
+Sucker, $uch a weight as may ju$t $uffice
+to draw it to the bottom of the Cylinder.
+And having thus examin'd what weight is
+nece$$ary to draw down the Sucker, when
+the Atmo$phere makes no other then the
+ordinary re$i$tance of the Air again$t its
+de$cent; the Sucker mu$t be again forc'd
+to the top of the Cylinder, who$e upper
+Orifice mu$t now be exactly clo$ed; and
+then (the fir$t weight remaining) we ea$i-
+ly may, by hanging a Scale to the above-
+mention'd Iron (that makes part of the
+Sucker) ca$t in known weights $o long,
+till in $pight of the reluctancy of the At-
+mo$phere the Sucker be drawn down. For
+to the$e weights in the Scale, that of the
+Scale it $elf being added, the $um will give
+us the weight of a Column of Air, equal
+in Diameter to the Sucker, or to the ca-
+vity of the Cylinder; and in length to
+the heighth of the Atmo$phere.
+<p>According to this method we did, $ince
+<pb n=238>
+the writing of the la$t Experiment, at-
+tempt to mea$ure the pre$$ure of the At-
+mo$phere, but found it more difficult then
+we expected, to perform it with any ac-
+curatene$s; for though by the help of the
+<I>Manubrium</I> the Sucker moved up and
+down with $o much ea$e, that one would
+have thought that both its convex $urface,
+and the concave one of the Cylinder were
+exqui$itely $mooth, &amp; as it were $lippery;
+yet when the Sucker came to be moved
+onely with a dead weight or pre$$ure (that
+was not (like the force of him that
+pump'd) intended as occa$ion required)
+we found that the little rufne$$es, or other
+inequalities, and perhaps too, the unequal
+pre$$ure of the Leather again$t the cavity
+of the Cylinder, were able now and then
+to put a $top to the de$cent or a$cent of
+the Sucker, though a very little external
+help would ea$ily $urmount that impedi-
+ment; and then the Sucker would, for a
+while, continue its formerly interrupted
+motion, though that a$$i$tance were with-
+drawn. But this di$couragement did not
+deterre us from pro$ecuting our Experi-
+ment, and endeavoring, by a careful trial,
+to make it as in$tructive as we could.
+We found then that a Leaden Weight,
+<pb n=239>
+of 28 pounds (each con$i$ting of $ixteen
+Ounces) being fa$tned to one of the teeth
+of the Sucker, drew it down $lowly e-
+nough; when the upper Orifice of the
+Cylinder was left open, though by the
+help of Oyl and Water, and by the fre-
+quent moving the Sucker up and down
+with the <I>Manubrium,</I> its motion in the
+Cylinder had been before purpo$ely faci-
+litated. This done, the upper Orifice of
+the Cylinder was very carefully and clo$e-
+ly $topp'd, the Valve being likewi$e $hut
+with its wonted Stopple well oyl'd, af-
+ter the Sucker had been again impell'd
+up to the top of the Cylinder. Then to
+the precedent twenty eight pound, we
+added a hundred and twelve pounds more,
+which forcing down the Sucker, though
+but lei$urely, we took off the twenty
+eight pound weight; and being unable to
+procure ju$t $uch weights as we would
+have had, we hung on, in$tead of it, one
+of fourteen pound, but found that, with
+the re$t, unable to carry down the Sucker.
+And to $atisfie our $elves, and the Spe-
+ctators, that it was the re$i$tance of the
+ambient Air that hinder'd the de$cent of
+$o great a weight, after that we had try'd
+that upon un$topping the Valve, and
+<pb n=240>
+thereby opening an acce$s to the external
+Air, the Sucker would be immediately
+drawn down: After this, I $ay, we made
+this further Experiment, That having by
+a Man's $trength forcibly depre$$'d the
+Sucker to the bottom of the Cylinder,
+and then fa$tned weights to the above-
+named Iron that makes part of that Suc-
+ker, the pre$$ure of the external Air find-
+ing little or nothing in the cavity of the
+evacuated Cylinder to re$i$t it, did pre-
+$ently begin to impell the Sucker, with
+the weights that clogg'd it, towards the
+upper part of the Cylinder, till $ome
+$uch accidental Impediment as we former-
+ly mention'd, check'd its cour$e; and
+when that rub, which ea$ily might be, was
+taken out of the way, it would continue
+its a$cent to the top, to the no $mall won-
+der of tho$e By $tanders, that could not
+comprehend how $uch a weight could a$-
+cend, as it were, of it $elf; that is, with-
+out any vi$ible force, or $o much as Su-
+ction to lift it up. And indeed it is very
+con$iderable, that though po$$ibly there
+might remain $ome particles of Air in the
+Cylinder, after the drawing down of the
+Sucker; yet the pre$$ure of a Cylinder of
+the Atmo$phere, $omewhat le$s then
+<pb n=241>
+three Inches in Diameter (for, as it was
+$aid in the de$cription of our Engine, the
+cavity of the Cylinder was no broader)
+was able, uncompre$$'d, not only to $u$tain,
+but even to drive up a weight of an hun-
+dred and odde pounds: for be$ides the
+weight of the whole Sucker it $elf, which
+amounts to $ome pounds, the weights an-
+nexed to it made up a hundred and three
+pounds, be$ides an Iron Bar, that by con-
+jecture weighed two pounds more; and
+yet all the$e together fall $omewhat $hort
+of the weight which we lately mention'd,
+the re$i$tance of the Air to have held $u-
+$pended in the cavity of the Cylinder.
+<p>And though (as hath been already ac-
+knowledg'd) we cannot, peradventure,
+obtain by the recited means $o exact an
+account as were to be wi$h'd, of what we
+would di$cover: Yet, if it $erve us to
+ground Conjectures more approaching to
+the Truth, then we have hitherto met
+with, I hope it will be con$ider'd (which
+a famous Poet judiciou$ly $ays)
+<C><I>E$t quoddam prodire tenus, $i non da-
+tur ultra.</I></C>
+<p>Peradventure it will not be imperti-
+<pb n=242>
+nent to annex to the other Circum$tances
+that have been already $ee down concern-
+ing this Experiment, That it was made in
+Winter, in Weather neither Fro$ty nor
+Rainy, about the change of the Moon,
+and at a place who$e latitude is near about
+51<SUP>d</SUP> and a half: For perhaps the force or
+pre$$ure of the Air may vary, according
+to the Sea$ons of the Year, the tempera-
+ture of the Weather, the elevation of the
+Pole, or the pha$es of the Moon; all, or
+even any of them $eeming capable to al-
+ter either the heighth or con$i$tence of the
+incumbent Atmo$phere: And therefore
+it would not be ami$s if this Experiment
+were carefully tryd at $everal times and
+places, with variety of Circum$tances. It
+might al$o be try'd with Cylinders of $e-
+veral Diameters, exqui$itely fitted with
+Suckers, that we might know what pro-
+portion $everal Pillars of the Atmo$phere
+bear, to the Weights they are able to $u-
+$tain or lift up; and con$equently, whe-
+ther the increa$e or decrement of the re-
+$i$tance of the ambient Air, can be re-
+duc'd to any regular proportion to the
+Diameters of the Suckers: The$e, and
+divers other $uch things which may be
+try'd with this Cylinder, might mo$t of
+<pb n=243>
+them bemore exactly try'd by the To<*>-
+cellian Experiment, if we could get Tubes
+$o accurately blown and drawn, that the
+Cavity were perfectly Cylindrical.
+<p>To dwell upon all the $everal Refle-
+ctions, that a $peculative Wit might
+make upon this and the foregoing Expe-
+riment: (I mean the thirty third and thir-
+ty $econd, would require almo$t a Vo-
+lume, whereas our occa$ions will $carce
+allow us time to touch upon three or
+four of the chief Inferences that $eem de-
+ducible from them, and therefore we $hall
+content our $elves to point at tho$e
+few.
+<p>And fir$t, as many other <I>Ph&aelig;nomena</I>
+of our Engine, $o e$pecially, the two
+lately mention'd Experiments, $eem ve-
+ry much to call in que$tion the receiv'd
+Opinion of the Nature or Cau$e of Su-
+ction. For 'tis true indeed, that when men
+$uck, they commonly u$e $ome manife$t
+endeavour by a peculiar motion of their
+Mouthes, Che$ts, and $ome other con$pi-
+ring parts, to convey to them the body
+to be $uckt in. And hence perhaps they
+have taken occa$ion, to think that in all
+<pb n=244>
+Suction there mu$t be $ome Endeavour
+or motion in the $ucking to attract the
+$ucked Body. But in our la$t Experi-
+ment it appeares not at all how the up-
+per part of the empty'd Cylinder that re-
+maines movele$s all the while, or any
+part of it, does at all endeavour to draw
+to it the depre$$ed Sucker and the an-
+nex'd weights. And yet tho$e that be-
+hold the a$cention of the Sucker, without
+$eriou$ly con$idering the cau$e of it, doe
+readily conclude it to be ray$'d by $ome-
+thing that powerfully Sucks or attracts
+it, though they $ee not what that may
+be or where it lurks. So that it $eemes
+not ab$olutely nece$$ary to Suction, that
+there be in the Body, which is $aid to $uck,
+an endeavor or motion in order thereun-
+to, but rather that Suction may be at lea$t
+for the mo$t part reduc'd to Pul$ion, and
+its effects a$crib'd to $uch a pre$$ure of
+the neighboring air upon tho$e Bodies
+(whther a&euml;rial, or of other Natures) that
+are contiguous to the Body that is $ayd to
+attract them, as is $tronger than that Sub-
+$tance which po$$e$$es the cavity of that
+$ucking Body is able to re$i$t. To ob-
+ject here, that it was $ome particles of
+Air remaining in the empty'd Cylin-
+<pb n=245>
+der that attracted this weight to obviate
+a <I>Vacuum,</I> will $carce be $atisfactory; un-
+le$s it can be cleerly made out by what li-
+tle hooks, or other grappling In$truments,
+the internal Air could take hold of the
+Sucker; how $o litle of it obtain'd the
+force to lift up $o great a weight; and why
+al$o, upon the letting in of a litle more
+Air into one of our evacuated Ve$-
+$els, the attraction is, in$tead of being
+$trengthen'd, much weaken'd, though,
+if there were danger of a <I>Vacuum</I> be-
+fore, it would remain, notwith$tanding
+this ingre$s of a little Air. For that $till
+there remain'd in the capacity of the ex-
+hau$ted Cylinder $tore of little rooms,
+or $paces empty or devoid of Air, may
+appear by the great violence wherewith
+the air ru$hes in, if any way be open'd to it.
+And that 'tis not $o much the decrement
+of the <I>Vacuum</I> within the cavity of the
+ve$$el that debilitates the attraction, as the
+$pring of the included air (who$e pre$ence
+makes the decrement) that does it by
+re$i$ting the pre$$ure of the external Air,
+$eems probable, partly from the Di$abi-
+lity of vacuities, whether greater or le$$er,
+to re$i$t the pre$$ure of the Air; and part-
+ly by $ome of the <I>Ph&aelig;nomena</I> of our Ex-
+<pb n=246>
+periments, and particularly by this Cir-
+cum$tance of the three and Thirtieth,
+that the Sucker was by the pre$$ure of the
+Ambient Air impell'd upwards, with its
+weight hanging at it, not only when it
+was at the bottome of the Cylinder, and
+con$equently left a great <I>Vacuum</I> in the
+cavity of it; but when the Sucker had
+been already impel'd almo$t to the top of
+the Cylinder, and con$equently, when the
+<I>Vacuum</I> that remain'd was become very
+litle in compari$on of that which preceded
+the beginning of the Sucker's a$cention.
+<p>In the next place, the$e Experiments
+may teach us, what to judge of the vul-
+gar Axiom receiv'd for $o many Ages
+as an undoubted Truth in the Peripate-
+tick Schools; That Nature abhorres
+and flys a <I>Vacuum,</I> and that to $uch a de-
+gree, that no humane power (to go no
+higher) is able to make one in the Uni-
+ver$e; wherein Heaven and Earth would
+change places, and all its other Bodyes
+rather act contrary to their own Nature,
+than $uffer it. For, if by a <I>Vacuum</I> we
+will under$tand a place perfectly devoid
+of all corporeal Sub$tance, it may be in-
+deed then, as we formerly noted be plau-
+$ibly enough maintain'd, that there is
+<pb n=247>
+no $uch thing in the world; but that the
+generality of the Pleni$ts, (e$pecially till
+of late yeares $ome of them grew more
+wary) did not take a <I>Vacuum</I> in $o $trict
+a Sen$e, may appear by the Experiments
+formerly, and ev'n to this Day imploy'd
+by the Deniers of a Vacuum, to prove it
+impo$$ible that there can be any made.
+For when they alleadge (for In$tance)
+that when a man $ucks Water through a
+long Pipe, that heavy Liquor, contrary
+to its Nature, a$cends into the Sucker's
+mouth, only, to fill up that room made
+by the Dilatation of his Bre$t and
+Lungs, which otherwi$e will in part be
+empty. And when they tell us, that the
+rea$on why if a long Pipe exactly
+clos'd at one end be fill'd top-ful
+of Water, and then inverted, no Liquor
+will fall out of the open Orifice; Or, to
+u$e a more familiar Example, when they
+teach, that the cau$e why in a Gardiner's
+watering Pot $hap'd conically, or like a
+Sugar-Loaf fill'd with Water, no Liquor
+fals down through the numerous holes
+at the bottome, whil$t the Gardiner keeps
+his Thumb upon the Orifice of the litle
+hole at the top, and no longer, mu$t be
+that it in the ca$e propo$ed the Water
+<pb n=248>
+$hould de$cend, the Air being unable to
+$ucceed it, there would be left at the up-
+per and de$erted part of the Ve$$el a <I>Va-
+cuum,</I> that would be avoided if the hole
+at the top were open'd. When (I $ay)
+they alleadge $uch Experiments, the
+Tendency of them $eems plainly to im-
+port, that they mean, by a <I>Vacuum,</I> any
+$pace here below that is not fill'd with a
+vi$ible body, or at lea$t with Air; though
+it be not quite devoy'd of all Body what-
+$oever. For why $hould Nature, out of
+her dete$tation of a <I>Vacuum,</I> make Bo-
+dies act contrary to their own Tendency,
+that a place may be fill'd with Air, if its
+being $o were not nece$$ary to the avoi-
+ding of a <I>Vacuum.</I>
+<p>Taking then a <I>Vacuum</I> in this vulgar
+and obvious $ence, the common opinion
+about it $eems lyable to $everal Exce-
+ptions, whereof $ome of the chief are
+$ugge$ted to us by our Engine.
+<p>It will not ea$ily then be intelligibly
+made out, how hatred or aver$ation,
+which is a pa$$ion of the Soule, can either
+for a <I>Vacuum,</I> or any other object, be $up-
+pos'd to be in Water, or $uch like inani-
+mate Body, which cannot be pre$um'd
+to know when a <I>Vacuum</I> would en$ue; if
+<pb n=249>
+they did not be$tirre them$elves to pre-
+vent it, nor to be $o generous as to act
+contrary to what is mo$t conducive to
+their own particular pre$ervation for the
+publique good of the Univer$e. As much
+then of intelligible and probable Truth,
+as is contain'd in this Metaphoricall Ex-
+pre$$ion, $eems to amount but to this;
+That by the Wi$e Author of Nature
+(who is ju$tly $ayd to have made all
+things in number, weight, and mea$ure,)
+the Univer$e, and the parts of it, are $o
+contriv'd, that it is as hard to make a <I>Va-
+cuum</I> in it, as if they $tudiou$ly con$pir'd
+to prevent it. And how far this it $elfe
+may be granted, de$erves to be further
+con$ider'd.
+<p>For in the next place, our Experiments
+$eem to teach, that the $uppo$ed Aver$a-
+tion of Nature to a <I>Vacuum</I> is but acci-
+dental, or in con$equence partly of the
+Weight and Fluidity, or, at lea$t, Fluxi-
+lity of the Bodies here below; and partly,
+and perhaps principally, of the Spring of
+the air, who$e re$tle$s endeavor to expand
+it $elfe every way, makes it either ru<*>h
+in it $elfe, or compel the interpos'd bo-
+dys into all $paces, where it finds no grea-
+ter re$i$tance than it can $urmount. And
+<pb n=250>
+that in tho$e motions which are made <I>ob-
+fugamVacui</I> (as the common phra$e is) Bo-
+dys act without $uch genero$ity &amp; Con-
+$ideration, as is wont to be a$crib'd to
+them, is apparent enough in our 32<SUP>d</SUP> Ex-
+periment, where the torrent of Air, that
+$eem'd to $trive to get into the Empty'd
+Receiver, did plainly prevent its own
+De$igne, by $o impelling the Value, as
+to make it $hut the only Orifice the Air
+was to get in at. And if afterwards ei-
+ther Nature, or the internal Air, had a de-
+$igne the external Air $hould be attra-
+cted, they $eem'd to pro$ecute very un-
+wi$ely by continuing to $uck the Valve
+$o $trongly, when they found that by
+that Sucction the Valve it $elfe could not
+be drawn in: Whereas by forbearing to
+$uck, the Valve would by it's own weight
+have fall'n down, and $uffer'd the exclu-
+ded Air to returne freely, and to fill
+again the exhau$ted Ve$$el.
+<p>And this minds me to take notice of
+another deficiency, pointed at by our Ex-
+periments in the common Doctrine of
+tho$e Pleni$ts we rea$on with; for many
+of tho$e unu$ual motions in Bodies, that
+are $ayd to be made to e$cape a <I>Vacuum,</I>
+$eem rather made to fill it. For why,
+<pb n=251>
+to in$tance in our newly mention'd Ex-
+periment, a$$oon as the Valve was de-
+pre$s'd by the weight we hung at it,
+$hould the Air $o impetuou$ly and copi-
+ou$ly ru$h into the cavity of the Receiver;
+if there were before no vacant room there
+to receive it? and if there were, then all the
+while the Valve kept out the Air, tho$e
+litle $paces in the Receiver, which the
+corpu$cles of that Air afterwards fill'd,
+may be concluded to have remain'd em-
+pty. So that the $eeming violence,
+imploy'd by Nature on the occa$ion of
+the evacuating of the Ve$$el, $eems to
+have come too late to hinder the making
+of Vacuities in the Receiver, and only
+to have, a$$oon as we permitted, fill'd
+up with Air tho$e that were already
+made.
+<p>And as for the Care of the Publique
+Good of the Univer$e a$crib'd to dead
+and $tupid Bodies, wee $hall only de-
+mand, why in our 19<SUP>th</SUP> Experiment, upon
+the Ex$uction of the ambient Air, the
+Water de$erted the upper half of the
+Gla$s-Tube; and did not a$cend to fill
+it up, till the external Air was let in upon
+it: whereas by its ea$y and $udden regai-
+ning that upper part of the Tube, it
+<pb n=252>
+appear'd both that there was there much
+$pace devoid of Air, and that the Water
+might with $mall or no re$i$tance have
+a$cended into it, if it could have done $o
+without the impul$ion of the readmitted
+Air; which, it $eems, was nece$$ary to
+mind the Water of its formerly neglected
+Duty to the Univer$e.
+<p>Nay, for ought appeares, ev'n when
+the excluded Air, a$$oon as 'twas per-
+mitted, ru$ht violently into our exhau-
+$ted Receiver, that flowing in of the
+Air proceeded rather from the deter-
+minate Force of the Spring of the
+neighbouring Air, then from any endea-
+vour to fill up, much le$s to prevent va-
+cuity's. For though when as much Air as
+will, is gotten into our Receiver our pre-
+$ent Opponents take it for granted that
+it is full of Air; yet if it be remembred
+that when we made our 17<SUP>th</SUP> Experiment
+we crouded in more Air to our Receiver
+than it u$ually holds; and if we al$o con-
+$ider (which is much more) the Air of
+the $ame con$i$tence with that in our
+Receiver may in wind guns, as is known,
+and as we have try'd, be compre$$ed at
+lea$t into halfe its wonted room (I $ay at
+lea$t, becau$e $ome affirme, that the Air
+<pb n=253>
+may be thru$t into an 8<SUP>th</SUP>, or a yet $maller
+part of its ordinary extent) it $eems ne-
+ce$$ary to admit either a notion of conden-
+$ation &amp; rarefaction that is not intelligi-
+ble, or that in the capacity of our Recei-
+ver when pre$um'd to be full of Air, there
+yet remain'd as much of $pace as was ta-
+ken up by all the a&euml;rial corpu$cles unpo$-
+$e$$ed by the Air. Which $eemes plainly,
+to infer that the Air that ru$h'd into our
+empty'd ve$$el did not doe it preci$ely
+to fill up the Vacuities of it, $ince it left $o
+many unfill'd, but rather was thru$t in by
+the pre$$ure of the contiguous Air; which
+as it could not, but be always ready to ex-
+pand it $elfe, where it found lea$t re$i-
+$tance, $o was it unable to fill the Recei-
+ver any more, then until the Air within
+was reduc'd to the $ame mea$ure of Com-
+pactne$s with that without.
+<p>We may al$o from our two already of-
+ten mention'd Experiments further de-
+duce, that, ($ince Natures hatred of a
+<I>Vacuum</I> is but Metaphorical and Ac-
+cidental, being but a con$equence or re-
+$ult of the pre$$ure of the Air and of the
+Gravity, and partly al$o of the Fluxility
+of $ome other bodies) The power $hee
+makes u$e of to hinder a Vacuum, is not
+<pb n=254>
+(as we have el$e-where al$o noted) any
+$uch boundle$s thing as men have been
+pleas'd to imagine. And the rea$on, why
+in the former Experiments, mentioned
+in favour of the Pleni$ts, Bodies $eem to
+forget their own Natures to $hun a <I>Va-
+cuum,</I> $eems to be but this; That in the
+alleadged ca$es the weight of that Wa-
+ter that was either kept from falling or
+impell'd up, was not great enough to
+$urmount the pre$$ure of the contiguous
+Air; which, if it had been, the Water
+would have $ub$ided, though no Air could
+have $ucceeded. For not to repeat that
+Experiment of Mon$ieur <I>Pa$chal</I> (for-
+merly mention'd to have been try'd in a
+Gla$s exceeding 32 Foot) wherein the
+inverted Pipe being long enough to con-
+tain a competent weight of Water, that
+Liquor freely ran out at the lower Orifice:
+Not to mention this (I $ay) we $aw in
+our nineteenth Experiment, that when
+the pre$$ure of the ambient Air was $uffi-
+ciently weaken'd, the Water would fall
+out apace at the Orifice even of a $hort
+Pipe, though the Air could not $ucceed
+into the room de$erted by it. And it were
+not ami$s if tryal were made on the tops
+of very high Mountains, to di$cover with
+<pb n=255>
+what ea$e a <I>Vacuum</I> could be made near
+the confines of the Atmo$phere, where
+the Air is probably but light in compari-
+$on of what it is here below. But our
+pre$ent (three and thirtieth) Experiment
+$eems to manife$t, not onely that the
+power, exerci$'d by Nature, to $hun or re-
+pleni$h a <I>Vacuum,</I> is limited, but that it
+may be determin'd even to Pounds and
+Ounces: In$omuch that we might $ay,
+$uch a weight Nature will $u$tain or will
+lift up to re$i$t a <I>Vacuum</I> in our Engine;
+but if an Ounce more be added to that
+weight, it will $urmount Her $o much
+magnifi'd dete$tation of Vacuities. And
+thus, My Lord, our Experiments may
+not onely an$wer tho$e of the Pleni$ts,
+but enable us to retort their Arguments
+again$t them$elves: $ince, if that be true
+which they alleadge, that, when Water
+falls not down according to its nature, in
+a Body wherein no Air can $ucceed to fill
+up the place it mu$t leave, the $u$pen$i-
+on of the Liquor is made <I>Ne detur Vacu-
+um,</I> (as they $peak) it will follow, that
+if the Water can be brought to $ub$ide
+in $uch a ca$e, that de$erted $pace may be
+deem'd empty, according to their own
+Doctrine; e$pecially, $ince Nature (as
+<pb n=256>
+they would per$wade us) be$tirs her $elf
+$o mightily to keep it from being de-
+$erted.
+<p>I hope I $hall not need to reminde Your
+Lord$hip, that I have all this while been
+$peaking of a <I>Vacuum,</I> not in the $trict
+and Philo$ophical $en$e, but in that more
+obvious and familiar one that has been
+formerly declar'd.
+<p>And therefore I $hall now proceed to
+ob$erve in the la$t place, that our 33<SUP>d</SUP> Ex-
+periment affords us a notable proof of the
+unheeded $trength of that pre$$ure which
+is $u$tain'd by the Corpu$cles of what we
+call the free Air, and pre$ume to be un-
+compre$$'d. For, as fluid and yielding a
+Body as it is, our Experiment teaches us,
+That ev'n in our Climate, and without
+any other compre$$ion then what is (at
+lea$t here below) Natural, or (to $peak
+more properly) ordinary to it, it bears $o
+$trongly upon the Bodies whereunto it is
+contiguous, that a Cylinder of this free
+Air, not exceeding three Inches in Dia-
+meter is able to rai$e and carry up a
+weight, amounting to between $ixteen
+and $eventeen hundred Ounces. I $aid,
+<pb n=257>
+even in our Climate, becau$e that is tem-
+<MARG><I>Aere $rig<*>-
+do exi$tcate
+tardius mo-
+<*>entur Au-
+tomat a qu&atilde;
+acre ca<*>ida,
+adco qui-
+dem ut Au-
+tomaton
+quod Delg&aelig;
+in Nova
+Zembla a-
+gentes in &aelig;-
+dibus $u<*>s
+collocave-
+runt, omal-
+no &agrave; motis
+ce$$ave<*>it
+<*>t$i m<*>
+malus toa-
+dus ei addidi$$ent quam antea ferre $olebat.</I> Varenius Geo: Genevat <*>.
+111. Propo: 7. pag. 648.</MARG>
+perate enough; and as far as my ob$er-
+vations a$$i$t me to conjecture, the Air in
+many other more Northern Countries
+may be much thicker, and able to $upport
+a greater weight: which is not to be
+doubted of, if there be no mi$take in
+what is Recorded concerning the <I>Hollan-
+ders,</I> that were forc'd by the Ice to Win-
+ter in <I>Nova Zembla,</I> namely, That
+they found there $o conden$'d an Air, that
+they could not make their Clock goe,
+ev'n by a very great addition to the
+weights that were wont to move it.
+<p>I $uppo$e Your Lord$hip will readily
+take notice, that I might very ea$ily have
+di$cour$ed much more fully and accuratly
+then I have done, again$t the common o-
+pinion touching Suction, and touching na-
+tures hatred of a <I>Vacuum.</I> But I was willing
+to keep my $elf to tho$e con$iderations
+touching the$e matters, that might be ve-
+rifi'd by our Engine it $elf, e$pecially, $ince,
+as I $aid at fir$t, it would take up too much
+time to in$i$t particularly upon all the Re-
+flections that may be made even upon our
+two la$t Experiments. And therefore,
+<pb n=258>
+pa$$ing to the next, I $hall leave it to your
+Lord$hip to con$ider how far the$e tryals
+of ours will either confirm or disfavor
+the new Doctrine of $everal eminent Na-
+turali$ts, who teach, That in all motion
+there is nece$$arily a Circle of Bodies, as
+they $peak, moving together; and whe-
+ther the Circles in $uch motion be an Ac-
+cidental or Con$equential thing or no.
+<p>TIs a known thing to tho$e that are con-
+<MARG><I>Experi-
+ment</I> 34.</MARG>
+ver$ant in the Hydro$taticks, That
+two Bodies which in the Air are of equal
+weight, but of unequal bulk, as Gold,
+for in$tance and Iron, being afterwards
+weighed in Water, will lo$e their <I>&AElig;qui-
+librium</I> upon the change of the ambient
+Body, $o that the Gold will $ink lower
+then the Iron; which, by rea$on of its
+greater bulk, has more Water to lift
+or di$place, that it may $ink. By Analogy
+to this Experiment, it $eem'd probable,
+that if two weights did in our Engine
+ballance each other, when the Gla$s was
+full of Air; upon the ex$uction of a
+great part of that Air, $o notable a change
+in the con$i$tence of the ambient Body,
+<pb n=259>
+would make them lo$e their <I>&AElig;quili-
+brium.</I>
+<p>But being de$irous at the $ame time to
+make a tryal, for a certain De$ign that
+needs not here be mention'd, we took
+for one of our weights a dry Bladder,
+$trongly tyed at the Neck, and about
+half fill'd with Air (that being a weight
+both $light, and that would expand it
+$elf in the evacuated Gla$s) and fa$tning
+that to one part of our formerly menti-
+on'd exact ballance (which turns with the
+32<SUP>d</SUP> part of a Grain) we put a Metalline
+counterpoi$e into the oppo$ite Scale; and
+$o the two weights being brought to an
+<I>&AElig;quilibrium,</I> the ballance was convey'd
+into the Receiver, and $u$pended from the
+Cover of it.
+<p>But before we proceed further, we mu$t
+note, That pre$ently after the laying on
+of the Cover, the Bladder appear'd to
+preponderate, whereupon the Scales being
+taken out, and reduc'd very near to an <I>&AElig;-
+quilibrium,</I> yet $o, that a little advantage
+remain'd on that $ide to which the Metal-
+line weight belong'd; they were again let
+down into the Receiver, which was pre-
+$ently made fa$t with Plai$ter, and a hot
+Iron: Soon after which, before the Pump
+<pb n=260>
+was employ'd, the Bladder $eem'd again
+a little to preponderate. Afterwards
+the Air in the Gla$s being begun to be
+drawn out, the Biadder began (according
+to the formerly mention'd Ob$ervations)
+to expand it $elf, and manife$tly to out-
+weigh the oppo$ite weight, drawing
+down the Scale to which it was fa$tned
+very much beneath the other, e$pecially
+when the Air had $well'd it to its full ex-
+tent.
+<p>This done, we very lei$urely let in the
+external Air; and ob$erv'd, that upon
+the flagging of the Bladder, the Scale
+whereto it was fa$tned, not onely by de-
+grees return'd to an <I>&AElig;quilibrium</I> with the
+other, but at length was a little out-
+weighed by it.
+<p>But becau$e we $u$pected there
+might have interven'd $ome unheeded
+Circum$tance in this la$t part of the Ex-
+periment, we would not pre$ently take
+out the Scales, nor meddle with the Co-
+ver, but leaving things as they were, we
+perceiv'd, that after a little while the
+Bladder began again to preponderate, and
+by degrees to $ink lower and lower for
+divers hours; wherefore, leaving the
+Ve$$el clo$'d up all night, we repair'd to it
+<pb n=261>
+next Morning, and found the Bladder
+fallen yet lower. As if the very $ub$tance
+of it, had imbibed $ome of the moi$ture
+wherewith the Air (the Sea$on being ve-
+ry rainy) did then abound: As Lute-
+$trings, which are made likewi$e of the
+Membranous parts of Guts, $trongly
+wreath'd, are known to $well $o much,
+oftentimes as to break in rainy and wet
+weather. Which conjecture is the more to
+beregarded, becau$e congruou$ly unto it
+one of the company having a little warm'd
+the Bladder, found it then lighter then
+the oppo$ite weight. But this mu$t be
+look'd upon as a bare conjecture, till we
+can gain time to make further tryals about
+it. In the mean while we $hall adde, that
+without removing the Scales or the Co-
+ver of the Receiver, we again cau$'d the
+Air to be drawn out (the weather conti-
+ing very moi$t) but found not any manife$t
+alteration in the ballance; whether be-
+cau$e the <I>&AElig;quilibrium</I> was too far lo$t to
+let a $mall change appear, we determine
+not.
+<p>But to make the Experiment with a
+Body le$s apt to be altered by the tempe-
+rature of the Air, then was the Bladder;
+we brought the Scales again to an <I>&AElig;qui-</I>
+<pb n=262>
+<I>librium</I> with two weights, whereof the
+one was of Lead, the other of Cork. And
+having evacuated the Receiver, we ob$er-
+ved, that both upon the ex$uction, and
+after the return of the Air, the Cork did
+manife$tly preponderate, and much more
+a while after the Air had been let in again,
+then whil$t it was kept out. Wherefore,
+in the room of the Cork, we $ub$tituted
+a piece of Char-coal, as le$s likely to im-
+bibe any moi$ture from the Air, but the
+event proved much the $ame with that
+newly related: So that this Experiment
+$eems more liable to Ca$ualties then any,
+excepting one we have made in our En-
+gine. And as it is difficult to prevent
+them, $o it $eems not very ea$ie to di$-
+cover the cau$es of them, whereof we
+$hall therefore at pre$ent forbear mention-
+ing our Conjectures.
+<p>SOme Learned Mathematicians have of
+<MARG><I>Experi-
+ment</I> 35.</MARG>
+late ingenio&ugrave;$ly endeavored to reduce
+Filters to <I>Siphons;</I> but $till the true cau$e
+of the a$cen$ion of Water, and other Li-
+quors, both in <I>Siphons</I> and in Filtration,
+needing (for ought we have yet found) a
+clearer Di$covery and Explication, we
+<pb n=263>
+were de$irous to try whether or no the
+pre$$ure of the Air might rea$onably be
+$uppo$'d to have either the principal, or at
+lea$t a con$iderable Intere$t in the rai$ing
+of tho$e Liquors. But becau$e we found
+that we could not yet $o evacuate our Re-
+ceiver, but that the remaining Air,
+though but little in compari$on of the
+exhau$ted, would be able to impell the
+the Water to a greater height then is
+u$ual in ordinary Filtrations: we re$olved,
+in$tead of a Li$t of Cotton, or the like
+Filtre, to make u$e of a <I>Siphon</I> of Gla$s,
+delineated in the third Figure, con$i$t-
+ing of three pieces, two $traight, and
+the third crooked to joyn them toge-
+ther; who$e Junctures were diligently
+clo$'d, that no Air might finde entrance
+at them. One of the Legs of this <I>Si-
+phon</I> was (as it $hould be) $omewhat
+longer then the other, and was pervious
+at the bottom of it onely, by a hole al-
+mo$t as $lender as a hair, that the
+Water might but very lea$urely drop
+out of it, le$t it $hould all run out
+before the Experiment were compleat-
+ed. The other and $horter Leg of
+the <I>Siphon</I> was quite open at the end,
+and of the $ame widene$$e with the
+<pb n=264>
+re$t of the Pipe, who$e bore was about <*>/4
+of an Inch. The whole Siphon made
+up of the$e $everal pieces put together,
+was de$ign'd to be about a Foot and a
+half long; that the remaining Air, when
+the Ve$$el was exhau$ted after the wont-
+ed manner, might not be able to impell
+the Water to the top of the <I>Siphon;</I>
+which being inverted, was fill'd with Wa-
+ter, and of which the Shorter leg being
+let down two or three Inches deep into a
+Gla$s Ve$$el full of Water, and the up-
+per parts of it being fa$ten'd to the in$ide
+of the Cover of the Receiver, we pro-
+ceeded to clo$e fir$t, and then to empty
+the Ve$$el.
+<p>The effect of the tryal was this, that
+till a pretty quantity of Air had been
+drawn out, the Water dropp'd freely out
+at the lower end of the lower leg of the
+<I>Siphon,</I> as if the Experiment had been
+performed in the free Air. But afterwards,
+the Bubbles (as had been apprehended)
+began to di$clo$e them$elves in the Wa-
+ter, and a$cending to the top of the <I>Si-
+phon,</I> imbodyed them$elves there into
+one, which was augmented little by little
+by the ri$ing of other bubbles that from
+time to time broke into it, but much
+<pb n=278>
+fir$t we thought might be $ome $tain up-
+on the Gla$s; but after, finding it to
+be in divers Qualities like the Oyl,
+and Salt of the Concrete we were Di-
+$tilling, we began to $u$pect that the
+mo$t $ubtle and fugitive parts of the im-
+petuou$ly a$cending Steams, had pene-
+trated the $ub$tance (as they $peak) of
+the Gla$s, and by the cold of the am-
+bient Air were conden$'d on the $ur-
+face of it. And though we were ve-
+ry backward to credit this $u$pition, and
+therefore call'd in an Ingenious Per$on
+or two, both to a$$i$t us in the Ob-
+$ervation, and have Witne$s of its e-
+vent, we continued a while longer to
+watch the e$cape of $uch unctuous Fumes,
+and upon the whole matter unanimou$ly
+concluded, That all things con$ider'd,
+the $ubtle parts of the di$till'd matter
+being violently agitated, by the exce$-
+$ive heat had pa$$'d through the Pores
+of the Gla$s, widen'd by the $ame heat.
+But this having never happen'd but
+once in any of the Di$tillations we have
+either made or $een, though the$e be
+not a few, it is much more rea$onable
+to $uppo$e, that the perviou$ne$s of
+our Receiver to a Body much more
+<pb n=279>
+$ubtle then Air, proceeded partly from
+the loo$er Texture of that particular
+parcel of Gla$s the Receiver was made
+of (for Experience has taught us, that
+all Gla$s is not of the $ame compact-
+ne$s and $olidity) and partly from the
+enormous heat, which, together with
+the vehement agitation of the pene-
+trant Spirits, open'd the Pores of the
+Gla$s; then to imagine that $uch a
+$ub$tance as Air, $hould be able to per-
+meate the Body of Gla$s contrary to
+the te$timony of a thou$and Chymical
+and Mechanical Experiments, and of
+many of tho$e made in our Engine, e-
+$pecially that newly recited: Nay, by
+our fifth Experiment it appears, that
+a thin Bladder will not at its Pores
+give pa$$age even to rarified Air. And
+on this occa$ion we will annex an Ex-
+periment, which has made $ome of
+tho$e we have acquainted with it,
+doubt, whether the Corpu$cles of the
+Air be not le$$e $ubtle then tho$e of
+Water.
+<p>But without examining here the
+rea$onablene$$e of that doubt, we will
+proceed to recite the Experiment it $elf,
+which $eems to teach, That though Air,
+<pb n=280>
+when $ufficiently compre$$'d, may per-
+chance get entrance into narrower holes
+and crannies then Water; yet unle$s the
+Air be forc'd in at $uch very little holes,
+it will not get in at them, though they
+may be big enough to let Water pa$s
+through them.
+<p>The Experiment then was this: I took
+a fair Gla$s <I>Siphon,</I> the lower end of
+who$e longe$t Leg was drawn by degrees
+to $uch a $lenderne$s, that the Orifice, at
+which the Water was to fall out, would
+hardly admit a very $mall Pin: This <I>Si-
+phon</I> being inverted, the matter was $o
+order'd, that a little Bubble of Air was
+intercepted in the $lendere$t part of the
+<I>Siphon,</I> betwixt the little hole newly men-
+tion'd, and the incumbent Water, upon
+which, it came to pa$s, that the Air be-
+ing not to be forc'd through $o narrow a
+pa$$age, by $o light a Cylinder of Water,
+though amounting to the length of divers
+Inches, as lean'd upon it, hinder'd the
+further Efflux of the Water, as long as I
+plea$'d to let it $tay in that narrow place:
+whereas, when by blowing a little at the
+wider end of the <I>Siphon,</I> that little par-
+cel of Air was forc'd out with $ome Wa-
+ter, the remaining Water, that before
+<pb n=281>
+continu'd $u$pended, began freely to drop
+down again as formerly. And if you
+take a Gla$s Pipe, whether it be in the
+form of a <I>Siphon,</I> or no, that being for
+the mo$t part of the thickne$s of a Mans
+Finger, is yet towards one end $o $len-
+der, as to terminate in a hole almo$t as
+$mall as a Hor$e-hair; and if you fill this
+Pipe with Water, you will finde that Li-
+quor to drop down freely enough tho-
+row the $lender Extream: But if you then
+invert the Pipe, you will finde that the
+Air will not ea$ily get in at the $ame hole
+through which the Water pa$$'d. For in
+the $harp end of the Pipe, $ome Inches
+of Water will remain $u$pended, which
+'tis probable would not happen, if the
+Air could get in to $ucceed it, $ince if the
+hole were a little wider, the Water would
+immediatly $ub$ide. And though it be
+true, that if the Pipe be of the length of
+many Inches, a great part of the Wa-
+ter will run down at the wider Orifice, yet
+that $eems to happen for $ome other rea-
+$on, then becau$e the Air $ucceeds it at
+the upper and narrow Orifice, $ince all the
+$lender part of the Pipe, and perhaps
+$ome Inches more, will continue full of
+Water.
+<pb n=282>
+<p>And on this occa$ion I remember, that
+whereas it appears by our fifth Experi-
+ment, That the A&euml;rial Corpu$cles (ex-
+cept perhaps $ome that are extraordinari-
+ly fine) will not pa$$e thorow the Pores
+of a Lambs Bladder, yet Particles of Wa-
+ter will, as we have long $ince ob$erv'd,
+and as may be ea$ily try'd, by very clo$e-
+ly tying a little <I>Alcalizate</I> Salt (we u$'d
+the Calx of Tartar, made with Nitre)
+in a fine Bladder, and dipping the lower
+end of the Bladder in Water; for if you
+hold it there for a competent while, you
+will finde that there will $train thorow the
+Pores of the Bladder Water enough to
+di$$olve the Salt into a Liquor.
+<p>But I $ee I am $lipt into a Digre$$ion,
+wherefore I will not examine, whether,
+the Experiment I have related, proceed-
+ed from hence, That the $pringy Texture
+of the Corpu$cles of the Air, makes
+them le$s apt to yield and accommodate
+them$elves ea$ily to the narrow Pores of
+Bodies, then the more flexible Particles
+of Water; or whether it may more pro-
+babiy be a$crib'd to $ome other Cau$e.
+Nor will I $tay to con$ider how far we may
+hence be a$$i$ted to ghe$s at the cau$e of
+the a$cen$ion of Water in the $lender
+<pb n=283>
+Pipes and <I>Siphons</I> formerly mention'd,
+but will return to our Bubble; and take
+notice, That we thought fit al$o to en-
+deavor to mea$ure the capacity of the
+Bubble we had made u$e of, by filling
+it with Water, that we might the better
+know how much Water an$wered in
+weight to 3/4 of a Grain of Air, but not-
+with$tanding all the diligence that was
+u$ed to pre$erve $o brittle a Ve$$el, it
+broke before we could perfect what we
+were about, and we were not then pro-
+vided of another Bubble fit for our
+turn.
+<p>The ha$te I was in, My Lord, when I
+$ent away the la$t Sheet, made me forget
+to take notice to you of a Problem that
+occurr'd to my thoughts, upon the oc-
+ca$ion of the $low breaking of the Gla$s
+Bubble in our evacuated Receiver. For
+it may $eem $trange, $ince by our $ixth
+Experiment it appears, that the Air, when
+permitted, will by its own internal Spring
+expand it $elfe twice as much as <I>Mer-
+$ennus</I> was able to expand it, by the
+heat even of a candent <I>&AElig;olipile:</I> Yet
+the <I>Elater</I> of the Air was $carce able to
+break a very thin Gla$s Bubble, and ut-
+<pb n=284>
+terly unable to break one $omewhat thic-
+ker, within who$e cavity it was impri-
+$on'd; whereas Air pent up and agitated
+by heat is able to perform $o much more
+con$iderable effects, that (not to mention
+tho$e of Rarefaction that are more obvi-
+ous) the Learned Je$uit <I>Cab&aelig;us</I> (he that
+<MARG><I><*>: Ni<*>:
+<*>: lib:</I> 4.
+<I><*> A-
+<*></I></MARG>
+writ of the Load-$tone) relates, That he
+$aw a Marble Pillar ($o va$t, that three
+men together with di$play'd arms could
+not imbrace it, and that 1000 Yoke of
+Oxen drawing it $everal ways with all
+their $trength, could not have torn it
+a$$under) quite broken off in the mid$t,
+by rea$on of $ome Wood, which hap-
+pening to be burnt ju$t by the Pillar, the
+heat proceeding from the neighboring
+Fire, $o rarified $ome Air or Spirituous
+Matter which was $hut up in the cavities
+of the Marble, that it broke through the
+$olid Body of the Stone to obtain room
+to expand it $elf.
+<p>I remember I have taken notice that
+probably the rea$on why the included Air
+did not break the hermetically $eal'd Bub-
+bles that remain'd intire in our emptyed
+Receiver, was, That the Air, being $ome-
+what rarefied by the Flame imploy'd to
+clo$e the Gla$s, its Spring, upon the re-
+<pb n=285>
+ce$s of the heat, grew weaker then before.
+But though we reject not that ghe$s, yet
+it will not in the pre$ent ca$e $erve the
+turn, becau$e that much $maller Gla$s
+bubbles exactly clo$'d, will, by the in-
+cluded Air (though agitated but by the
+heat of a very moderate Fire) be made
+to fly in pieces. Whether we may be
+a$$i$ted to $alve this Problem, by con$i-
+dering that the heat does from within ve-
+hemently agitate the Corpu$cles of the
+Air, and adde its a$$i$tance to the Spring
+they had before, I $hall not now examine:
+$ince I here but propo$e a Problem, and
+that chiefly that by this memorable Story
+of <I>Cab&aelig;us,</I> notice may be taken of the
+prodigious power of Rarefaction, which
+hereby appears capable of performing
+$tranger things then any of our Experi-
+ments have hitherto a$crib'd to it.
+<p>We $hould hence, My Lord, imme-
+diatly proceed to the next Experiment,
+but that we think it fit, on this occa$ion,
+to acquaint You with what $ome former
+tryals (though not made in our Engine)
+have taught us, concerning what we
+would have di$cover'd by the newly
+mention'd Bubble that broke. And this
+the rather, becau$e (a great part of this
+<pb n=286>
+letter $uppo$ing the gravity of the Aire)
+it will not be impertinent to determine
+more particularly then hitherto we have
+done, what gravity we a$cribe to it.
+<p>We tooke then an <I>&AElig;olipile</I> made of
+copper, weighing $ix ounces, five drachms,
+and eight and forty graines: this being
+made as hot as we dur$t make it, (for feare
+of melting the mettle, or at lea$t the So-
+dar) was removed from the fire and im-
+mediately $topped with hard wax that no
+Aire at all might get in at the little
+hole wont to be left in <I>&AElig;olipiles</I> for the
+fumes to i$$ue out at: Then the <I>&AElig;olipile</I>
+being $uffer'd lea$urely to coole was again
+weighed together with the wax that $topt
+it, and was found to weigh (by rea$on of
+the additionall weight of the wax) $ix
+ounces, $ixe drachmes, and 39 graines.
+La$tly, the wax being perforated without
+taking any of it out of the Scale, the
+externall Aire was $uffered to ru$h in
+(which it did with $ome noy$e) and then
+the <I>&AElig;olipile</I> and wax, being againe
+weighed amounted to $ix ounces, $ix
+drachmes, and 50. graines. So that the
+<I>&AElig;olipile</I> freed as farre as our fire could
+free it, from it's Aire, weighed le$$e then
+<pb n=287>
+it $elfe when repleni$hed with Air, full
+eleven graines. That is, the Air contain-
+able within the cavity of the <I>&AElig;olipile</I> a-
+mounted to eleven graines and $omewhat
+more; I $ay $omewhat more, becau$e of
+the particles of the Air, that were not
+driven by the fire out of the <I>&AElig;olipile.</I>
+And by the way (if there be no mi$take
+in the ob$ervations of the diligent <I>Mer-
+$ennus</I>) it may $eeme $trange that it $hould
+$o much differ from 2. or 3. of ours; in
+none of which we could rarifie the Air in
+our &AElig;<I>olipile</I> (though made red hot almo$t
+all over, and $o immediately plung'd into
+cold water) to halfe that degree which he
+mentions, namely to 70. times it's natu-
+rall extent, unle$$e it were that the <I>&AElig;o-
+lipile</I> he imploy'd was able to $u$taine
+a more vehement heat then ours (which
+yet we kept in $o great an one, that once
+the $oder melting, it fell a$under into the
+two Hemi$pheres it con$i$ts of.)
+<p>The fore-mentioned way of weighing
+the Air by the help of an <I>&AElig;olipile,</I> $eems
+$omewhat more exact then that which
+<I>Mer$ennus</I> u$ed, In that in ours the <I>&AElig;oli-
+pile</I> was not weighed, till it was cold;
+whereas in his, being weighed red hot, it
+<pb n=288>
+$ubject to loo$e of it's $nb$tance in the
+cooling, for (as we have el$ewhere noted
+on another occa$ion) Copper heated red
+hot is wont in the cooling to throw off
+little thin $cales in $uch plenty, that having
+purpo$ely watcht a Copper <I>&AElig;olipile</I> du-
+ring its refrigeration, we have $een the
+place round about it almo$t covered with
+tho$e little $cales it had every way $cat-
+ter'd: which, however they amount not
+to much, ought not to be over-looked,
+when 'tis $o light a body as Air, that is
+to be weighed. We will not examine,
+whether the &AElig;<I>olipile</I> in cooling may not
+receive $ome little increment of weight,
+either from the vapid or $aline Steames
+that wander up and downe in the Air: But
+we will rather mention, that (for the grea-
+ter exactne$$e) we imployed to weigh our
+<I>&AElig;olipile,</I> both when fill'd onely with Air
+and when repleni$ht with Water, a paire
+of $cales that would turne (as they $peak)
+with the fourth part of a grain.
+<p>As to the proportion of weight be-
+twixt Air and Water, $ome learned men
+have attempted it by wayes $o unaccurate
+that they $eeme to have much mi$taken
+it. For (not to mention the improbable
+accounts of <I>Kepler</I> and others.) The l<*>ar-
+<pb n=289>
+ned and diligent <I>Ricciolus,</I> having pur-
+po$ely endeavoured to inve$tigate this
+proportion by meanes of a thin blad-
+der, e$timates the weight of the Air to
+that of the Water to be as one to ten
+thou$and, or thereabouts. And indeed I re-
+member that having formerly, on a cer-
+tain occa$ion, weighed a large bladder full
+of Air, and found it when the Air was all
+$quee$ed out, to have contained fourteen
+graines of Air. I found the $ame bladder
+afterwards fill'd with water to containe
+very neer 14. pound of that liquor: accor-
+ding to which account, the proportion of
+Air to Water was almo$t as a graine to a
+pound, that is, as one to above 7600. To
+this we may adde, that on the other $ide,
+<I>Galileo</I> him$elfe u$ing another, but an un-
+accurate way too, defined the Air to be
+in weight to Water, but as one to 4. hun-
+dred. But the way formerly propo$ed of
+weighing the Air by an &AElig;<I>olipile,</I> $eemes
+by great oddes more exact; and (as farre
+as we could ghe$$e) $eemed to agree well
+enough with the experiment made in our
+Receiver. Wherefore it will be be$t to
+tru$t our &AElig;<I>olipile</I> in the enquiry we are a-
+bout, and according to our ob$ervations
+the water it contained amounting to one
+<pb n=290>
+and twenty ounces and an halfe, and as
+much Air as was requi$ite to fill it weigh-
+ing eleven graines, the proportion in gra-
+vity of Air to Water of the $ame bulk
+will be as one to 938. And though we
+could not fill the &AElig;<I>olipile</I> with water, $o
+exactly as we would, yet in regard we
+could not either as perfectly as we would,
+drive the Air out of it by heat; we think
+the proportion may well enough hold:
+but tho$e that are delighted with round
+numbers (as the phra$e is) will not be
+much mi$taken if they reckon water to be
+neere a thou$and times heavier than Air.
+And (for further proof that we have made
+the proportion betwixt the$e two bodies
+rather greater then le$$er then indeed it is;
+and al$o to confirme our former ob$erva-
+tion of the weight of the Air) we will adde,
+That, having another time put $ome Wa-
+ter into the &AElig;<I>olipile</I> before we $et it on
+the fire, that the copious vapours of the
+rarefied liquor might the better drive out
+the Air, we found, upon try all carefully
+made, that when the &AElig;<I>olipile</I> was refrige-
+rated, and the included vapours were by
+the cold turned againe into water (which
+could not have happen'd to the Air, that
+the preceeding Steams expell'd) the Air,
+<pb n=291>
+when it was let in, increa$'d the weight of
+the <I>&AElig;olipile</I> as much as before, namely,
+Eleven Grains; though there were alrea-
+dy in it twelve Drachmes and a half, be-
+$ides a couple of Grains of Water, which
+remain'd of that we had formerly put in-
+to it to drive out the Air.
+<p><I>Mer$ennus</I> indeed tells us, that by his
+account Air is in weight to Water, as 1 to
+1356. And adds, that we may, without
+any danger, believe that the gravity of
+Water to that of Air of a like bulk, is
+not le$s then of 1300 to 1. And con$e-
+quently, that the quantity of Air to a
+quantity of Water equiponderant there-
+to, is as 1300 to 1. But why we $hould
+relinqui$h our own carefully repeated try-
+als, I $ee not. Yet I am unwilling to re-
+ject tho$e of $o accurate and u$eful a Wri-
+ter: And therefore $hall propo$e a way
+of reconciling our differing Ob$ervations,
+by pre$enting, that the di$crepance be-
+tween them may probably ari$e from the
+differing con$i$tence of the Air at <I>London</I>
+and at <I>Paris:</I> For our Air being more cold
+and moi$t, then that which Your Lord-
+$hip now breaths, may be $uppo$'d al$o
+to be a fourth or fifth part more heavy. I
+leave it to be con$ider'd, whether it be of
+<pb n=292>
+any moment that our Ob$ervations were
+made in the mid$t of Winter, whereas his
+were perhaps made in $ome warmer time
+of the Year. But I think it were not a-
+mi$s that, by the method formerly pro-
+po$'d, the gravity of the Air were ob-
+$erv'd both in $everal Countries, and in
+the $ame Country, in the $everal Sea$ons
+of the Year and differing Temperatures of
+the Weather. And I would give $ome-
+thing of value to know the weight of $uch
+an <I>&AElig;olipile</I> as ours full of air in the mid$t
+of Winter in <I>Nova Zembla,</I> if that be
+true which we formerly took notice of,
+namely, That the <I>Hollanders,</I> who Win-
+tered there, found that Air $o thick that
+their Clock would not go.
+<p>If Your Lord$hip $hould now ask me,
+if I could not by the help of the$e, and
+our other Ob$ervations, decide the Con-
+trover$ies of our Modern Mathematici-
+ans about the height of the Air or Atmo-
+$phere, by determining how high it doth
+indeed reach: I $hould an$wer, That
+though it $eems ea$ie enough to $hew that
+divers Famous and Applauded Writers
+have been mi$taken in a$$igning the heigth
+of the Atmo$phere: Yet it $eems very
+difficult preci$ely to define of what height
+<pb n=293>
+it is. And becau$e we have hitherto but
+lightly touch'd upon a matter of $uch im-
+portance, we pre$ume it wil not be thought
+impertinent, upon this occa$ion, to annex
+$omething towards the Elucidation of
+it.
+<p>What we have already try'd and newly
+$et down, allows us to take it for granted,
+that (at lea$t about <I>London</I>) the propor-
+tion of gravity betwixt Water and Air,
+of equal bulk, is as of a thou$and to
+one.
+<p>The next thing therefore that we are
+to enquire after, in order to our pre$ent
+de$ign, is the difference in weight betwixt
+Water and Quick-$ilver: And though
+this hath been defin'd already by the Il-
+lu$trious <I>Verulam,</I> and $ome other inqui-
+$itive Per$ons, that have compar'd the
+weight of $everal Bodies, and ca$t their
+Ob$ervations into Tables, yet we $hall
+not $cruple to annex our own tryals about
+it: Partly, becau$e we finde Authors
+con$iderably to di$-agree; partly, becau$e
+we u$'d exacter Scales, and a $omewhat
+more wary method then others $eem to
+have done: And partly al$o, becau$e ha-
+ving pro$ecuted our inquiry by two or
+three $everal ways; the $mall difference
+<pb n=294>
+between the events may a$$ure us that we
+were not much mi$taken.
+<p>We took then a Gla$s Pipe, of the
+form of an inverted <I>Siphon,</I> who$e $hape
+is delineated in the $ixteenth Figure: And
+pouring into it a quantity of Quick $ilver,
+we held it $o, that the $uperficies of the
+Liquor, both in the longer and $horter
+leg, lay in a Horizontal Line, denoted in
+the Scheme by the prick'd Line EF; then
+pouring Water into the longer Leg of the
+<I>Siphon,</I> till that was almo$t fill'd, we ob-
+$erv'd the $urface of the Quick-$ilver in
+that leg to be, by the weight of the Wa-
+ter, depre$$'d, as from E to B; and in
+the $horter leg, to be as much impell'd
+upward as from F to G: Whereupon ha-
+ving formerly $tuck marks, as well at the
+point B, as at the oppo$ite point D, we
+mealur d both the di$tance DC to have
+the height of the Cylinder of Quick-$il-
+ver, which was rai$'d above the Point D
+(level with the $urface of the Quick-$ilver
+in the other leg) by the weight of the Wa-
+ter, and the di$tance BA which gave us
+the height of the Cylinder of Water. So
+that the di$tance DC amounting to (2 1<*>/54)
+Inches, and the height of the Water a-
+mounting (30 45/51) Inches; and the whole
+<pb n=295>
+numbers on both $ides, which the annex-
+ed Fractions being reduc'd to improper
+Fractions of the $ame denomination, the
+proportion appear'd to be (the denomi-
+nators beng left out as equal on both $ides)
+as 121 to 1665; or by reduction, as one
+to (13 92/121).
+<p>Be$ides this unu$ual way of determi-
+ning the gravity of $ome things, we mea-
+$ur'd the proportion betwixt Quick-$ilver
+and Water, by the help of $o exact a bal-
+lance, as loo$es its <I>&AElig;quilibrium</I> by the
+hundredth part of a Grain. But becau$e
+there is wont to be committed an over-
+$ight in weighing Quick-$ilver and Wa-
+ter, e$pecially if the Orifice of the Ve$$el
+wherein they are put be any thing wide, in
+regard that men heed not that the $urface
+of Water in Ve$$els will be concave,
+but that of Quick-$ilver, notably convex
+or protuberant: To avoid this u$ual over-
+$ight (I $ay) we made u$e of a gla$s bubble,
+blown very thin at the Flame of a Lamp,
+that it might not be too heavy for the
+Ballance, and terminating in a very $lender
+neck, wherein the concavity or convexity
+of a Liquor could not be con$iderable:
+This Gla$s weighing 23 1/2 Grains, we fill'd
+<pb n=296>
+almo$t with Quick-$ilver, and fa$tning a
+mark over again$t the middle of the pro-
+tuberant Superficies as near as our Eyes
+could judge, we found that the Quick-
+$ilver alone weighed 299 <*> Grains: Then
+the Quick-$ilver being pour'd out, and
+the $ame Gla$s being fill'd as full of com-
+mon Water, we found the Liquor to
+weigh 21 7/8 Grains. Whereby it appear'd
+that the weight of Water to Quick-
+$ilver, is as one to (13 19/28): Though our Il-
+lu$trious <I>Verulam</I> (que$tionle$s not for
+want of Judgement or Care, but of ex-
+act In$truments) makes the proportion
+betwixt tho$e two Liquors to be greater
+then of 1 to 17. And to adde, that up-
+on the by, $ince Quick-$ilver and well
+rectified Spirit of Wine, are (how ju$tly
+I $ay not) accounted, the one the hea-
+vie$t, and the other the lighte$t of Li-
+quors; we thought to fill in the $ame
+Gla$s, and with the $ame Scales to ob-
+$erve the difference betwixt them, which
+we found to be as of 1 to (16 641/1084); where-
+by it appear'd, That the difference be-
+twixt Spirit of Wine, that may be made
+to burn all away, ($uch as was ours) and
+common Water, is as betwixt 1 and (1 44/171)
+<pb n=297>
+<p>We might here take occa$ion to ad-
+mire, that though Water (as appear'd by
+the Experiment formerly mention'd of
+the Pewter Ve$$el) $eems not capable of
+any con$iderable conden$ation, and $eems
+not to have inter$per$'d in it any $tore of
+Air; yet Quick-$ilver, of no greater bulk
+then Water, $hould weigh near fourteen
+times as much. But having onely point-
+ed at this as a thing worthy of con$idera-
+tion, we will proceed in our inquiry after
+the heigth of the Atmo$phere: And to
+avoid the trouble of Fractions, we will
+a$$ume that Quick-$ilver is fourteen times
+as heavy as Water, $ince it wants $o little
+of being $o.
+<p>Wherefore having now given us the
+proportion of Air to Water, and Water
+to Quick-$ilver, it will be very ea$ie to
+finde the proportion betwixt Air and
+Quick-$ilver, in ca$e we will $uppo$e the
+Atmo$phere to be uniformly of $uch a
+con$i$tence as the Air we weighed here
+below. For $ince our Engine hath $uffi-
+<MARG><*></MARG>
+ciently manife$ted that 'tis the <I>&AElig;quili-
+brium</I> with the external Air, that in the
+<I>Torricellian</I> Experiment keeps the Quick-
+$ilver from $ub$iding; And $ince, by our
+accurate Experiment formerly mention'd,
+<pb n=298>
+it appears that a Cylinder of Mercury,
+able to ballance a Cylinder of the whole
+Atmo$phere, amounted to near about
+thirty Inches; and $ince, con$equently
+we may a$$ume the proportion of Quick-
+$ilver to Air to be as fourteen thou$and to
+one; it will follow, that a Cylinder of
+Air, capable to maintain an <I>&AElig;quilibrium,</I>
+with a Mercurial Cylinder of two Foot
+and an half in height, mu$t amount to
+35000 Feet of our Engli$h Mea$ure;
+and con$equently (reckoning five Foot
+to a Geometrical Pace, and one thou$and
+$uch Paces to a Mile) to $even full
+Miles.
+<p>But this (as we lately intimated) pro-
+ceeds upon the $uppo$ition, that the Air
+is every where of the $ame con$i$tence
+that we found it near the $urface of the
+Earth; but that cannot with any $afety
+be concluded, not onely for the rea$on I
+finde to have been taken notice of by the
+Antients, and thus expre$t in <I>Seneca:
+Omnis A&euml;r</I> ($ays he) <I>quo propior e$t terris</I>
+<MARG><*> 4.
+<*> 10.</MARG>
+<I>hoc cra$sior; quemadmodum in aqua &amp; in
+omni humore f&aelig;x ima e$t, it a in A&euml;re $pi$-
+$i&szlig;ima qu&aelig;&queacute; de$idunt;</I> but much more,
+becau$e the $pringy Texture of the A&euml;rial
+Corpu$cles, makes them capable of a
+<pb n=299>
+very great compre$$ion, which the weight
+of the incumbent part of the Atmo-
+$phere is very $ufficient to give tho$e that
+be undermo$t and near the $urface of the
+Earth. And if we recall to minde tho$e
+former Experiments, whereby we have
+manife$ted, That Air, much rarefied with-
+out heat, may ea$ily admit a further ra-
+refaction from heat; and that the Air, even
+without being expanded by heat, is capa-
+ble of being rarefied to above one hundred
+and fifty times the extent it u$ually po$-
+$e$$es here below; How can it be demon-
+$trated that the Atmo$phere may not, for
+ought we know, or at lea$t for ought can
+be determin'd by our Statical and Mecha-
+nical Experiments, ri$e to the height of
+Five and twenty <I>German</I> Leagues, if not
+of $ome hundred of common Miles?
+<p>And this conjecture it $elf may appear
+very injurious to the height whereunto
+Exhalations may a$cend, if we will allow
+<MARG><*></MARG>
+that there was no mi$take in that $trange
+Ob$ervation made at <I>Tolous</I> in a clear
+Night in <I>Augu$t,</I> by the diligent Ma-
+thematician <I>Emanuel Magnan,</I> and thus
+Recorded by <I>Ricciolus,</I> (for I have not at
+hand the Authors own Book) <I>Vidit</I> ($ays
+he) <I>ab hor a undecima po$t meridiem u$&queacute; ad</I>
+<pb n=300>
+<I>mediam noctem Lun&acirc; infra horizontem
+po$it&acirc;, nubeculam quandam lucidam prope
+Meridianum fere u$que ad Zenith diffu$am
+qu&aelig; con$ider at is omnibus non poter at ni$i &agrave;
+$ole illuminari; ideoque altior e$$e debuit
+tota umbr a terr&aelig;. Addit</I> (continues <I>Ricci-
+olus) $imile quid eveni$$e Michaeli Angelo
+Riccio apud Sabinos ver$anti nempe viro
+in Mathe$i eruditi$simo.</I>
+<p>Various Ob$ervations made at the
+feet, tops, and interjacent parts of high
+Mountains, might perchance $omewhat
+a$$i$t us to make an e$timate in what pro-
+portion, if in any certain one, the higher
+Air is thicker then the lower, and ghe$s
+at the di$-form con$i$tence, as to laxity
+and compactne$s of the Air at $everal
+di$tances from us. And if the difficul-
+ties about the refractions of the Cele$tial
+Lights, were $atisfactorily determin'd,
+that might al$o much conduce to the pla-
+cing due limits to the Atmo$phere (who$e
+Dimen$ions tho$e Ob$ervations about
+Refractions $eem hitherto much to con-
+tract.) But for the pre$ent we dare not
+pronounce any thing peremptorily con-
+cerning the height of it, but leave it to
+further inquiry: contenting our $elves to
+have manife$ted the mi$take of divers
+<pb n=301>
+eminent Modern Writers, who will not
+allow the Atmo$phere to exceed above
+two or three Miles in height (as the Fa-
+mous K<I>epler</I> will not the <I>A&euml;r refractivus</I>)
+and to have rendred a rea$on why in the
+mention we made in the Notes upon the
+fir$t Experiment, touching the height of
+the Atmo$phere, we $crupled not to $peak
+of it, as if it might be many Miles high.
+<p>WE will now proceed to recite a
+<MARG><I>Experi-
+ment</I> 37.</MARG>
+<I>Ph&aelig;nomenon,</I> which, though
+made among$t the fir$t, we thought fit
+not to mention till after many others, that
+we might have the opportunity to ob-
+$erve as many Circum$tances of it as we
+could, and $o pre$ent Your Lord$hip at
+once, mo$t of what we at $everal times
+have taken notice of concerning $o odde
+a <I>Ph&aelig;nomenon.</I>
+<p>Our Engine had not been long fini$h'd,
+when, at the fir$t lea$ure we could $teal
+from our occa$ions to make tryal of it,
+we cau$'d the Air to be pump'd out of
+the Receiver; and whil'$t I was bu$ied in
+entertaining a Learned Friend that ju$t
+then came to vi$it me, an Ingenious By-
+<pb n=302>
+$tander, thought he perceiv'd $ome new
+kind of Light in the Receiver, of which
+giving me ha$tily notice, my Friend and
+I pre$ently ob$erv'd, that when the Suc-
+ker was drawn down, immediately upon
+the turning of the Key, there appear'd
+a kinde of Light in the Receiver, almo$t
+like a faint fla$h of Lightening in the
+Day-time, and almo$t as $uddenly did it
+appear and vani$h. Having, not with-
+out $ome amazement, ob$erv'd divers
+of the$e Apparitions of Light, we took
+notice that the Day was clear, the hour
+about ten in the Morning, that the onely
+Window in the Room fac'd the North;
+and al$o, that by interpo$ing a Cloak, or
+any opacous Body between the Receiver
+and the Window, though the re$t of the
+Room were $ufficiently enlightned, yet
+the fla$hes did not appear as before, un-
+le$s the opacous Body were remov'd.
+But not being able on all the$e Circum-
+$tances to ground any firm Conjecture
+at the cau$e of this $urpri$ing <I>Ph&aelig;nome-
+non,</I> as $oon as Night was come, we
+made the Room very dark; and plying
+the Pump, as in the Morning, we could
+not, though we often try'd, find, upon
+the turning of the Key, $o much as the
+<pb n=303>
+lea$t glimmering of Light; whence we
+inferr'd, that the fla$h appearing in the
+Receiver, did not proceed from any new
+Light generated there, but from $ome
+reflections of the light of the Sun, or
+other Luminous Bodies plac'd without
+it; though whence that Reflection
+$hould proceed, it po$'d us to conje-
+cture.
+<p>Wherefore the next Morning, ho-
+ping to inform our $elves better, we
+went about to repeat the Experiment,
+but though we could as well as former-
+ly exhau$t the Receiver, though the
+place wherein we made the tryal was the
+very $ame; and though other Circum-
+$tances were re$embling, yet we could
+not di$cover the lea$t appearance of
+Light all that Day, nor on divers o-
+thers on which tryal was again fruitle$-
+ly made; nor can we to this very time
+be $ure a Day before hand that the$e
+Fla$hes will be to be $een in our great
+Receiver. Nay, having once found the
+Engine in a good humour (if I may
+$o $peak) to $hew this trick, and $ent
+notice of it to our Learned Friend
+Doctor <I>Wallis,</I> who expre$$'d a great
+<pb n=304>
+de$ire to $ee this <I>Ph&aelig;nomenon,</I> though he
+were not then above a Bow-$hoot off, and
+made ha$te to $atisfie his Curio$ity; yet
+by that time he was come, the thing he
+came for was no longer to be $een; $o
+that having vainly endeavored to exhibit
+again the <I>Ph&aelig;nomenon</I> in his pre$ence, I
+began to apprehend what he might think
+of me, when unexpectedly the Engine
+pre$ented us a fla$h, and after that a $econd,
+and as many more, as $uffic'd to $atisfie
+him that we might very well confidently
+relate, that we have our $elves $een this
+<I>Ph&aelig;nomenon,</I> though not confidently pro-
+mi$e to $hew it others.
+<p>And this un$ucce$sfulne$s whereto our
+Experiment is lyable, being $uch, that by
+all our watchfulne$s and tryals, we could
+never reduce it to any certain Rules or
+Ob$ervations; $ince in all con$titutions
+of the Weather, times of the Day, <I>&amp;c.</I>
+it will $ometimes an$wer, and $ometimes
+di$-appoint our Expectations; We are
+much di$courag'd from venturing to frame
+an <I>Hypothe$is</I> to give an account of it:
+which if the Experiment did con$tantly
+$ucceed, might the more hopefully be at-
+tempted; by the help of the following
+<I>Ph&aelig;nomena</I> laid together: $ome of them
+<pb n=305>
+produc'd upon tryals purpo$ely made
+to examine the validity of the conjectures,
+other tryals had $ugge$ted.
+<p>Fir$t then we ob$erv'd, that the Appa-
+rition of Light may be made as well by
+Candle-light, as by Day-light; and in
+whatever po$ition the Candle be held, in
+reference to the Receiver, as on this or
+that hand of it, above it, beneath it, or
+any other way, provided the Beams of
+Light be not hinder'd from falling upon
+the Ve$$el.
+<p>Next, we noted that the fla$h appears
+immediately upon the turning of the
+Key, to let the Air out of the Receiver
+into the empty'd Cylinder, in $o much
+that I remember not that when at any
+time in our great Receiver, the Stop-cock
+was open'd before the Cylinder was ex-
+hau$ted (whereby it came to pa$s that the
+Air did rather de$cend, then ru$h into the
+Cylinder) the often mention'd fla$h ap-
+pear'd to our eyes.
+<p>Yet, we further ob$erv'd, that when in-
+$tead of the great Receiver we made u$e
+of a $mall Gla$s, not containing above a
+pound and a half of Water, the <I>Ph&aelig;no-
+menon</I> might be exhibited though the
+Stop-cock were open, provided the
+<pb n=306>
+Sucker were drawn nimbly down.
+<p>We noted too, that when we began to
+empty the Receiver, the appearances of
+Light were much more con$picuous
+then towards the latter end, when little
+Air at a time could pa$s out of the Re-
+ceiver.
+<p>We ob$erv'd al$o, that when the Suc-
+ker had not been long before well Oyl'd,
+and in$tead of the great Receiver, the
+$maller Ve$$el above-mention'd was em-
+ploy'd; We ob$erv'd, I $ay, that then,
+upon the opening of the Stop-cock, as
+the Air de$cended out of the Gla$s in-
+to the empty'd Cylinder, $o at the $ame
+time there a$cended out of the Cylinder
+into the Ve$$el a certain Steam, which
+$eem'd to con$i$t of very little Bubbles,
+or other minute Corpu$cles thrown up
+from the Oyl, rarefied by the attrition it
+$uffered in the Cylinder. For at the
+$ame time that the$e Steams a$cended
+into the Gla$s, $ome of the $ame kinde
+manife$tly i$$ued out like a little Pillar of
+Smoke at the Orifice of the Valve, when
+that was occa$ionally open'd. And the$e
+Steams frequently enough pre$enting
+them$elves to our view, we found, by
+expo$ing the Gla$s to a clear Light, that
+<pb n=307>
+they were wont to play up and down
+in it, and $o by their whitei$hne$s, to e-
+mulate in $ome mea$ure the apparition of
+Light.
+<p>For we likewi$e $ometimes found, by
+watchful ob$ervation, that when the
+Fla$h was great, not onely at the very
+in$tant the Receiver lo$t of its tran$pa-
+rency, by appearing full of $ome kinde
+of whiti$h $ub$tance; but that for $ome
+$hort time after the $ides of the Gla$s
+continued $omewhat opacous, and
+$eem'd to be darken'd, as if $ome
+whiti$h Steam adher'd to the in$ide of
+them.
+<p>He that would render a Rea$on of
+the <I>Ph&aelig;nomenon,</I> whereof all the$e are
+not all the Circum$tances, mu$t doe
+two things; whereof the one is diffi-
+cult, and the other little le$s then im-
+po$$ible: For he mu$t give an Ac-
+count not onely whence the appearing
+whitene$s proceeds, but wherefore that
+whitene$s does $ometimes appear and
+$ometimes not.
+<p>For our part, we freely confe$$e
+our $elves at a lo$$e about rendering
+<pb n=308>
+a Rea$on of the le$s difficult part of the
+Problem: And though Your Lord-
+$hip $hould ev'n pre$s us to declare what
+Conjecture it was, that the above-recited
+Circum$tances $ugge$ted to us, we $hould
+propo$e the thoughts we then had, no o-
+therwi$e then as bare Conjectures.
+<p>In ca$e then our <I>Ph&aelig;nomenon</I> had con-
+$tantly and uniformly appear'd, we $hould
+have $u$pected it to have been produc'd
+after $ome $uch manner as follows.
+<p>Fir$t, we ob$erv'd that, though that
+which we $aw in our Receiver $eem'd to
+be $ome kinde of Light, yet it was indeed
+but a whitene$s which did (as hath alrea-
+dy been noted) opacate (as $ome $peak)
+the in$ide of the Gla$s.
+<p>Next we con$ider'd, that our com-
+mon Air abounds with Particles or little
+Bodies, capable to reflect the Beams of
+Light. Of this we might ea$ily give di-
+vers proofs, but we $hall name but two:
+The one, that vulgar ob$ervation of the
+Motes that appear in Multitudes $wim-
+ming up and down in the Air, when the
+Sun-beams $hooting into a Room, or any
+other $hady Place di$cover them, though
+otherwi$e the eye cannot di$tingui$h them
+<pb n=309>
+from the re$t of the Air: The other proof
+we will take from what we (and no doubt
+very many others) have ob$erv'd, touch-
+ing the Illumination of the Air in the
+Night. And we particularly remember,
+that, being at $ome di$tance from <I>London</I>
+one Night, that the People, upon a very
+well-come Occa$ion, te$tified their Joy
+by numerous Bon-fires; though, by rea-
+$on of the Interpo$ition of the Hou$es,
+we could not $ee the Fires them$elves, yet
+we could plainly $ee the Air all enlighten'd
+over and near the City; which argu'd,
+that the lucid Beams $hot upwards from
+the Fires, met in the Air with Corpu$cles
+opacous enough to reflect them to our
+Eyes.
+<p>A third thing that we con$idered, was,
+That white may be produc'd (without
+excluding other ways, or denying invi$i-
+ble Pores in the $olide$t Bodies) when
+the continuity of a Diaphanous Body
+happens to be interrupted by a great num-
+ber of Surfaces, which, like $o many
+little Looking-gla$$es, do confu$edly re-
+pre$ent a multitude of little and $eeming-
+ly contiguous Images of the elucid Body.
+We $hall not in$i$t on the explanation of
+this, but refer You for it to what we have
+<pb n=310>
+$aid in another Paper (touching Co-
+lours.) But the In$tances that $eem to
+prove it are obvious: For Water or whites
+of Eggs beaten to froth, do lo$e their
+tran$parency and appear white. And ha-
+ving out of one of our le$$er Receivers
+carefully drawn out the Air, and $o order'd
+it, that the hole by which the Water was
+to get in, was exceeding $mall, that the
+Liquor might be the more broken in its
+pa$$age thorow it, we ob$erv'd with plea-
+$ure, That, the Neck being held under
+Water, and the little hole newly men-
+tion'd being open'd, the Water that ru$h'd
+in was $o broken, and acquired $uch a mul-
+titude of new Surfaces, that the Receiver
+$eem'd to be full rather of Milk then Wa-
+ter. We have likewi$e found out, That
+by heating a lump of Cry$tal to a certain
+degree, and quenching it in fair Water, it
+would be di$continu'd by $uch a multi-
+tude of Cracks, (which created new Sur-
+faces within it) that though it would not
+fall a$under, but retain its former $hape,
+yet it would lo$e its tran$parency, and ap-
+pear white.
+<p>Upon the$e Con$iderations, My Lord,
+and $ome others, it $eem'd not ab$ur'd to
+imagine, That upon the ru$hing of the Air
+<pb n=311>
+out of the Receiver into the empty'd Cy-
+linder, the Air in the Receiver being $ud-
+denly and vehemently expanded, the Tex-
+ture of it was as $uddenly alter'd, and the
+parts made $o to $hift places (and perhaps
+$ome of them to change po$tures) as du-
+ring their new and vehement Motion and
+their varied Scituation, to di$turb the
+wonted continuity and $o the Diapha-
+neity of the Air; which (as we have alrea-
+dy noted) upon its cea$ing to be a tran-
+$parent Body, without the interpo$ition
+of colour'd things, mu$t ea$ily degene-
+rate into white.
+<p>Several things there were that made
+this Conjecture $eem the le$s improba-
+ble. As fir$t, That the whitene$s al-
+ways appear'd greater when the Ex$ucti-
+on began to be made, whil'$t there was
+$tore of Air in the Receiver, then when
+the Air was in great part drawn out. And
+next, That, having exhau$ted the Re-
+ceiver, and apply'd to the hole in the
+Stop-cock a large bubble of clear Gla$s, in
+$uch a manner, that we could at plea$ure let
+the Air pa$s out at the $mall Gla$s into the
+great one, and ea$ily fill the $mall one with
+Air again, We ob$erv'd with plea$ure,
+<pb n=312>
+That upon the opening the pa$$age be-
+twixt the two Gla$$es, the Air in the
+$maller having $o much room in the great-
+er to receive it, the Di$$ilition of that
+Air was $o great, that the $mall Viol
+$eem'd to be full of Milk; and this Expe-
+riment we repeated $everal times. To
+which we may adde, That, having pro-
+vided a $mall Receiver, who$e upper Ori-
+fice was $o narrow that I could $top it with
+my Thumb, I ob$erv'd, that when upon
+the Ex$uction of the Air the capacity of
+the Gla$s appear'd white, if by a $udden
+removal of my Thumb I let in the out-
+ward Air, that whitene$s would imme-
+diately vani$h. And whereas it may be
+objected, That in the In$tance formerly
+mention'd, Water turning from per$pi-
+cuous to white, there intervenes the Air,
+which is a Body of a Heterogeneous na-
+ture, and mu$t turn it into Bubbles to
+make it lo$e its tran$parency. We may
+borrow an An$wer from an Experiment
+we deliver in another Treati$e, where we
+teach how to make two very volatile Li-
+quors, which being gently put together
+are clear as Rock-water, and yet will al-
+mo$t in a moment, without the $ub-ingre$-
+$ion of Air to turn them into Bubbles, $o
+<pb n=313>
+alter the di$po$ition of their in$en$ible
+parts, as to become a white and con$i$tent
+Body. And this happens not as in the
+precipitation of <I>Benjamin,</I> and $ome o-
+ther Re$inous Bodies, which being di$-
+$olv'd in Spirit of Wine, may, by the effu-
+$ion of fair Water, be turn'd into a $eem-
+ingly Milky $ub$tance. For this white-
+ne$s belongs not to the whole Liquor, but
+to the Corpu$cles of the di$$olv'd Gum,
+which after a while $ub$iding leave the Li-
+quor tran$parent, them$elves onely re-
+maining white: Whereas in our ca$e, 'tis
+from the vary'd texture of the whole for-
+merly tran$parent fluid Body, and not
+from this or that part that this whitene$$e
+re$ults: For the Body is white thorowout,
+and will long continue $o; and yet may,
+in proce$s of time, without any addition,
+be totally reduc'd into a tran$parent Bo-
+dy as before.
+<p>But be$ides the Conjecture in$i$ted on
+all this while, we grounded another upon
+the following Ob$ervation, which was,
+That having convey'd $ome $moke into
+our Receiver plac'd again$t a Window, we
+ob$erv'd, that upon the ex$uction of the
+Air, the Corpu$cles that were $wimming
+in it, did manife$tly enough make the Re-
+<pb n=314>
+ceiver $eem more opacous at the very
+moment of the ru$hing out of the Air:
+For con$idering that the whitene$s, who$e
+cau$e we enquire of, did but $ometimes ap-
+pear, it $eem'd not impo$$ible but that at
+$uch times the Air in the Receiver might
+abound with Particles, capable of re-
+flecting the Light in the manner requi$ite
+to exhibit a white colour, by their being
+put into a certain unu$ual Motion. As
+may be in $ome mea$ure illu$trated by
+this, That the new motion of the fre$hly
+mention'd Fumes, made the in$ide of the
+Receiver appear $omewhat darker then
+before: And partly by the nature of our
+formerly mention'd $moking Liquor,
+who$e parts though they $eem'd tran$pa-
+rent whil'$t they compo$'d a Liquor, yet
+when the $ame Corpu$cles, upon the un-
+$topping of the Gla$s, were put into a
+new motion, and di$po$'d after a new
+manner, they did opacate that part of the
+Air they mov'd in, and exhibited a great-
+er whitene$s then that which $ometimes
+appears in our Pneumatical Ve$$el. Nor
+$hould we content our $elves with this $in-
+gle In$tance, to manife$t, That little Bo-
+dies, which being rang'd after one manner,
+are Diaphanous and Colourle$s, may, by
+<pb n=315>
+being barely agitated, di$per$'d, and con-
+$equently otherways rang'd, exhibite a
+colour, if we were not unwilling to rob
+our Collection of Experiments concern-
+ing Colours.
+<p>But, My Lord, I fore$ee You may
+make $ome Objections again$t our pro-
+po$ed ghe$s, which perhaps I $hall $carce
+be able to an$wer, e$pecially, if You in-
+$i$t upon having me render a Rea$on why
+our <I>Ph&aelig;nomenon</I> appears not con$tant-
+ly.
+<p>I might indeed an$wer, that probably
+it would do $o, if in$tead of our great
+Receiver we u$e $uch a $mall Viol as we
+have lat<I>e</I>ly mention'd, wherein the Di$$i-
+lition of the Air being much greater, is
+like to be the more con$picuous: Since I
+remember not that we ever made our try-
+al with $uch $mall Ve$$els, without find-
+ing the expected whitene$s to appear. But
+it would remain to be explicated, why in
+our great Receiver the <I>Ph&aelig;nomenon</I> $hould
+$ometimes be $een, and oftentimes not ap-
+pear. And though that Conjecture which
+we la$t made $hould not be rejected, yet if
+we were further pre$$'d to a$$ign a rea$on
+why the Air $hould abound with $uch Par-
+ticles, as we there $uppo$e, more at one
+<pb n=316>
+time then another, we are not yet pro-
+vided of any better An$wer, then this
+general one, That the Air about us,
+and much more that within the Receiver,
+may be much alter'd by $uch cau$es as few
+are aware of: For, not to repeat tho$e
+probable Arguments of this A$$ertion
+which we have occa$ionally mention'd
+here and there in the former part of this
+Epi$tle, we will here $et down two or
+three In$tances to verifie the $ame Propo-
+$ition. Fir$t, I finde that the Learned
+<I>Fo$ephus Aco$ta,</I> among other Judicious
+<MARG><*></MARG>
+Ob$ervations he made in <I>America,</I> hath
+this concerning the Effects of $ome
+Winds; <I>There are</I> ($ays he) <I>Winds which
+naturally trouble the Water of the Sea, and
+make it green, and black; others, clear as
+Cry$tal.</I> Next, we have ob$erv'd, That
+though we conveyd into the Receiver our
+Scales, and the <I>Pendula</I> formerly men-
+tion'd, clean and bright; yet after the Re-
+ceiver had been empty'd, and the Air let in
+again, the glo$s or lu$tre both of the one,
+and of the other, appear'd tarni$h'd by a
+beginning ru$t. And in the la$t place, we
+will $ubjoyn an Ob$ervation we made
+$ome Years ago, which hath been heard
+of by divers Ingenious Men, and $een
+<pb n=317>
+by $ome of them: We had, with pure
+Spirit of Wine, drawn a Tincture out of
+a certain Concrete which u$es to be rec-
+koned among Mineral Bodies; And this
+Tincture being very pure and tran$parent,
+we did, becau$e we put a great value upon
+it, put into a Cry$tal Viol which we care-
+fully $topp'd, and lock'd up in a Pre$s a-
+mong $ome other things that we $pecial-
+ly priz'd. This Liquor being a Chy-
+mical Rarity, and be$ides, very defecate
+and of a plea$ing Golden Colour; we
+had often occa$ion to look upon it, and
+$o to take notice, that one time it $eem'd
+to be very much troubled, and not clear
+as it was wont to be: Whereupon we ima-
+gined, that though it would be $omething
+$trange, yet it was not impo$$ible that
+$ome Precipitation of the Mineral Cor-
+pu$cles was then happening, and that
+thence the Liquor was opacated; but,
+finding after $ome days that though the
+expected Precipitation had not been
+made, yet the Liquor, retaining its for-
+mer vivid Colour, was grown clear again
+as before; we $omewhat wondered at it,
+and locking it up again in the $ame Pre$s,
+we re$olved to ob$erve, both whether
+the like changes would again appear in
+<pb n=318>
+our Tincture; and whether in ca$e they
+$hould appear, they would be a$cribable
+to the alterations of the Weather. But
+though, during the greate$t part of a Win-
+ter and a Spring, we took plea$ure to ob-
+$erve, how the Liquor would often grow
+turbid, and after a while clear again: Yet
+we could not finde that the$e Mutations
+depended upon any that were manife$t in
+the Air, whieh would be often dark and
+clouded, when the Tincture was clear and
+tran$parent; as on the other $ide, in clear
+Weather the Liquor would appear $ome-
+times troubled, and more opacous. So
+that being unable to give an account of
+the$e odde changes in our Tincture (which
+we $uppo$e we have not yet lo$t, though
+we know not whether it have lo$t its fickle
+Nature) either by tho$e of the Air, or
+any thing el$e that occurr'd to our
+thoughts; we could not but $u$pect that
+there may be in divers Bodies, as it were
+Spontaneous Mutations, that is, $uch
+changes as depend not upon manife$t
+Cau$es. But, My Lord, what has been
+all this while $aid concerning our <I>Ph&aelig;no-
+menon,</I> is offer'd to You, not as contain-
+ing a $atisfactory Account of it, but to
+a$$i$t You to give Your$elf one.
+<pb n=319>
+<p>WE took a Gla$s Ve$$el, open
+<MARG><I>Experi-
+ment</I> 38.</MARG>
+at the top, and into it we put
+a mixture of Snow and common Salt
+($uch a mixture as we have in another
+Treati$e largely di$cour$ed of) and in-
+to the mid$t of this mixture we $et a
+Gla$$e, of a Cylindrical form, clo$ely
+$topp'd at the lower end with Plai$ter,
+and open at the upper, at which we
+fill'd it with common Water. The$e
+things being let down into the Recei-
+ver, and the Pump being $et awork,
+the Snow began to melt $omewhat fa-
+$ter then we expected; whether upon
+the account of the Ex$uction of the
+Air, or becau$e there was but little of
+the Snow, or whether for any other
+Rea$on, it appeared doubtfull. But
+however, by that time the Receiver
+had been con$iderably exhau$ted, which
+was done in le$$e then 1/4 of an hour,
+we perceived the Water near the bot-
+tom of the Gla$s Cylinder to Freeze,
+and the Ice by a little longer $tay, $eem'd
+to encrea$e, and to ri$e $omewhat higher
+<pb n=320>
+then the $urface of the $urrounding Li-
+quor, where into almo$t all the Snow and
+Salt were re$olv'd. The Gla$s being ta-
+ken out, it appear'd that the Ice was as
+thick as the in$ide of the Gla$s it fill'd,
+though into that I could put my Thumb.
+The upper $urface of the Ice was very
+concave, which whether it were due to
+any unheeded accident, or to the ex$u-
+ction of the Air, we leave to be deter-
+min'd by further tryal. And la$tly, the
+Ice held again$t the Light, appear'd not
+de$titute of Bubbles, though $ome By-
+$tanders thought they were fewer then
+would have been found if the Water had
+been frozen in the open Air. The like
+Experiment we try'd al$o another time in
+one of our $mall Receivers, with not un-
+like $ucce$s.
+<p>And on this occa$ion, My Lord, give
+me leave to propo$e a Problem, which
+$hall be this: Whence proceeds that
+$trange force that we may $ometimes ob-
+$erve in frozen Water, to break the Bo-
+dies that Impri$on it, though hard and $o-
+lid? That there is $uch a force in Wa-
+ter expo$'d to Congelation, may be ga-
+ther'd not onely from what may be often
+ob$erv'd in Winter, of the bur$ting of
+<pb n=321>
+Gla$$es too clo$e $topp'd, fill'd with Wa-
+ter or aqueous Liquors, but by In$tances
+as much more con$iderable as le$s obvi-
+ous. For I remember, that an Ingenious
+Stone-cutter not long $ince complain'd to
+me, That $ometimes, through the negli-
+gence of Servants, the Rain being $uffer-
+ed to $oak into Marble Stones, the $uper-
+vening violent Fro$ts would bur$t the
+Stones, to the Profe$$ors no $mall dam-
+age. And I remember another Trades-
+man, in who$e Hou$e I had Lodgings, was
+la$t Winter complaining, that even Im-
+plements made of Bell-metal, being care-
+le$ly expo$'d to the wet, have been broken
+and $poil'd by the Water, which, having
+gotten into the little Cavities and Cran-
+nies of the Metal, was there afterwards
+frozen and expanded into Ice. And to
+the$e Relations, we can adde one of the
+<MARG><I>In <*>.</I> 4.
+<*></MARG>
+formerly mention'd <I>Cab&aelig;us's,</I> whereby
+they not onely may be confirm'd, but are
+$urpa$$'d: For he tells us, That he $aw a
+huge Ve$$el of exceeding hard Marble,
+$plit a$under by congel'd Water, who$e
+Rarefaction, $ays our Author, prov'd $o
+vehement, that the hardne$s of the Stone
+yielded to it; and $o a Ve$$el was broken,
+which would not have been $o by 100
+<pb n=322>
+Yoke of Oxen drawing it $everal ways. I
+know, My Lord, that to $olve this Pro-
+blem, it will be $aid, That Congelation
+does not (as is commonly, but erroneou$ly
+pre$um'd) reduce water into le$s room
+then it po$$e$$'d before, but rather makes
+it take up more. And I have el$ewhere
+prov'd by particular Experiments, That
+whether or no Ice may be truly $aid to be
+Water rarefi'd (for that $eems que$tion-
+able) it may be $aid to take up more room
+then the Water did before Glaciation.
+But though we grant that freezing makes
+Water $well, yet, how Cold (which in
+Weather-Gla$$es manife$tly condences
+the Air) $hould expand either the Water,
+or the intercepted Air $o forcibly, as to
+perform $uch things as we have newly re-
+lated, will yet remain a Problem.
+<p>WE took an Oval Gla$s, clear and
+<MARG><I>Experi-
+ment</I> 39.</MARG>
+(lea$t it $hould break) pretty
+$trong, with a $hort Neck at the obtu$er
+end, through this Neck, we thru$t almo$t
+to the bottom, a Pipe of Gla$s, which was
+clo$ely Cemented to the newly mention'd
+Neck, the upper part of which Pipe,
+was drawn in $ome places more $lender
+<pb n=323>
+then a Crows Quill, that the changes of
+the Air in that. Gla$s Egge might be the
+more con$picuous; Then there was con-
+vey'd into the Gla$s five or $ix Spoon-
+fulls of Water, part of which, by blow-
+ing Air into the Egge, was rai$'d into the
+above-mention'd $lender part of the Pipe,
+$o that the Water was interpo$'d between
+the external Air, and that included in the
+Egge. This Weather-gla$s (delineated
+in the fourteenth Figure) was $o plac'd,
+and clo$'d up in the cavity of one of our
+$mall Receivers, that onely the $lender
+part of the Pipe, to the heigth of four
+or five Inches, pa$$ing thorow a hole in
+the Cover, remain'd expo$'d to the open
+Air.
+<p>The Pump being $et a work, upon
+the Ex$uction of the Air, the Water in
+the Pipe de$cended about a quarter of an
+Inch, and this upon two or three reitera-
+ted tryals; which $eem'd $ufficiently to
+argue that there was no heat produc'd in
+the Receiver upon the Ex$uction of the
+Air: For even a little heat would pro-
+bably have been di$cover'd by that Wea-
+ther-gla$s, $ince upon the bare applica-
+tion of my hand to the out$ide of the
+Receiver, the warmth having after $ome
+<pb n=324>
+time been communicated or propagated
+through both the Gla$$es, and the inter-
+val betwixt them to the Impri$on'd Air,
+did $o rarifie that, as to inable it, by pre$-
+$ing upon the $ubjacent Water, to impel
+that in the Pipe very many times as far as
+it had fallen downwards upon the Ex$ucti-
+on of the Air.
+<p>Yet $hall not we conclude, that in the
+cavity of the Receiver the cold was great-
+er after the Ex$uction of the Air then be-
+fore.
+<p>For if it be demanded what then could
+cau$e the fore-mention'd $ub$iding of the
+Water? it may be an$wered, That pro-
+bably it was the reaching of the Gla$s
+Egge, which, upon the Ex$uction of the
+ambient Air, was unable to re$i$t alto-
+gether as much as formerly the pre$$ure of
+the included Air, and of the Atmo$phere,
+which by the interven$ion of the Water,
+pre$$'d upon its concave $urface: Which
+$eem'd probable, as well by what was a-
+bove deliver'd, in the Experiment about
+the breaking of the Gla$s by the force of
+the Atmo$phere; as by this notable Cir-
+cum$tance (which we divers times ob-
+$erv'd) That when by drawing the Air out
+of the Receiver, the Water in the Pipe
+<pb n=325>
+was $ub$ided, upon the readmi$$ion of the
+external Air to pre$s again$t the convex
+$urface of the Egge, the Water was pre-
+$ently re-impell'd to its former height:
+Which would perhaps appear le$s $trange
+to Your Lord$hip, if You had yet $een
+what we have heretofore taught in ano-
+ther Treati$e concerning the Spring that
+may be di$cover'd in Gla$s, as rigid and
+inflexible a Body as it is generally e-
+$teem'd. And in the mean while it may
+$erve the turn to cau$e a Gla$s Egge to be
+blown exceeding thin, and then, having
+broken it, try how far you can by degrees
+bend $ome narrow parts of it; and how
+readily, upon the removal of what kept
+it bent, it will re$tore it $elf to its former
+$tate or po$ture. But to return to our
+Experiment, From thence it $eems pro-
+bable, either that there $ucceeds no Bo-
+dy in the room of the Air drawn out of
+our Receiver, or that it is not every Mat-
+ter that is $ubtle enough readily to pa$s
+through the Pores of Gla$s, that is al-
+ways agitated enough to produce Heat
+where ever it is plentifully found. So that
+if no <I>Vacuum</I> be to be admitted, this Ex-
+periment $eems to invite us to allow a
+great di$parity, either as to bulk, or as to
+<pb n=326>
+agitation, or as to both, betwixt $ome
+parts of the Etherial Sub$tance, and tho$e
+that are wont here below to produce Heat
+and Fire.
+<p>We try'd al$o what Operation the
+drawing out of the Air would have upon
+Camphire, that being a Body, which,
+though not a Liquor, con$i$ts of $uch
+Volatile or Fugitive parts, that without
+any greater agitation then that of the open
+Air it $elf, they will copiou$ly flie away.
+But we found not that even this loo$e
+Body was $en$ibly alter'd by the Ex$ucti-
+on of the ambient Air.
+<p>IT may $eem well worth trying, whether
+<MARG><I>Experi-
+ment</I> 40.</MARG>
+or no in our exhau$ted Gla$s the want
+of an ambient Body, of the wonted thic-
+ne$s of Air, would di$able even light and
+little Animals, as Bees, and other winged
+In$ects, to flie. But though we ea$ily
+fore$aw how difficult it would be to make
+$uch an Experiment; yet not to omit our
+endeavors, we procur'd a large Fle$h-fly,
+which we convey'd into a $mall Receiver.
+We al$o another time $hut into a great
+Receiver a Humming Bee, that appear'd
+$trong and lively, though we had rather
+<pb n=327>
+have made the tryal with a Butter-fly, if
+the cold Sea$on would have permitted us
+to finde any. <note><I>Since the writing of this
+XLth Experiment, we pro-
+cur'd a wbite Butter-Fly,
+and inclo$'d it in one of our
+$maller Receivers, where,
+though at fir$t he fluttered
+up and down, yet pre$ently,
+upon the ex$uction of the
+Air, he fell down as <*>
+$woon, retaining no other
+motion then $ome little <*>-
+bling of the wings.</I></note> The Fly, af-
+ter $ome Ex$uctions of the
+Air, dropp'd down from the
+$ide of the Gla$s whereon $he
+was walking: But, that the
+Experiment with the Bee
+might be the more in$tructive,
+we convey'd in with her a bun-
+dle of Flowers, which re-
+main'd $u$pended by a $tring
+near the upper part of the Receiver: And
+having provok'd the Bee, we excited her
+to flie up and down the capacity of the
+Ve$$el, till at length, as we de$ir'd, $he
+lighted upon the Flowers; whereupon
+we pre$ently began to draw out the Air,
+and ob$erv'd, That though for $ome time
+the Bee $eem'd to take no notice of it, yet
+within awhile after $he did not flie, but fall
+down from rhe Flowers, without appear-
+ing to make any u$e of her Wings to help
+her $elf. But whether this fall of the Bee,
+and the other In$ect, proceeded from the
+mediums being too thin for them to flie in,
+or barely from the weakne$s, and as it were
+$wooning of the Animals them$elves, you
+will ea$ily gather from the following Ex-
+periment.
+<pb n=328>
+<p>TO $atisfie our $elves in $ome mea$ure,
+<MARG><I>Experi-
+ment</I> 41.</MARG>
+about the account upon which Re$pira-
+tion is $o nece$$ary to the Animals, that
+Nature hath furni$h'd with Lungs, we
+took (being then unable to procure any
+other lively Bird, $mall enough to be put
+into the Receiver) a Lark, one of who$e
+Wings had been broken by a $hot, of a
+Man that we had $ent to provide us $ome
+Birds for our Experiment; but notwith-
+$tanding this hurt, the Lark was very
+lively, and did, being put into the Recei-
+ver, divers times $pring up in it to a good
+height. The Ve$$el being ha$tily, but
+carefully clo$'d, the Pump was diligently
+ply'd, and the Bird for a while appear'd
+lively enough; but upon a greater Ex-
+$uction of the Air, $he began manife$tly
+to droop and appear $ick, and very $oon
+after was taken with as violent and irregu-
+lar Convul$ions, as are wont to be ob-
+$erv'd in Poultry, when their heads are
+wrung off: For the Bird threw her $elf
+over and over two or three times, and dy-
+ed with her Brea$t upward, her Head
+downwards, and her Neck awry. And
+though upon the appearing of the$e Con-
+<pb n=329>
+vul$ions, we turn'd the Stop-cock, and
+let in the Air upon her, yet it came too
+late; whereupon, ca$ting our eyes upon
+one of tho$e accurate Dyals that go with
+a <I>Pendulum,</I> and were of late ingeniou$ly
+invented by the Noble and Learned <I>Hu-
+genius,</I> we found that the whole Tragedy
+had been concluded within ten Minutes of
+an hour, part of which time had been im-
+ploy'd in cementing the Cover to the Re-
+ceiver. Soon after we got a Hen-$par-
+row, which being caught with Bird-lime
+was not at all hurt; when we put her into
+the Receiver, almo$t to the top of which
+$he would briskly rai$e her $elf, the Ex-
+periment being try'd with this Bird, as it
+was with the former, $he $eem'd to be
+dead within $even minutes, one of which
+were imploy'd in cementing on the Co-
+ver: But upon the $peedy turning of the
+Key, the fre$h Air flowing in, began $low-
+ly to revive her, $o that after $ome pant-
+ings $he open'd her eyes, and regain'd her
+feet, and in about a 1/4 of an hour, after
+threatned to make an e$cape at the top of
+the Gla$s, which had been un$topp'd to
+let in the fre$h Air upon her: But the Re-
+ceiver being clo$'d the $econd time, $he
+<pb n=330>
+was kill'd with violent Convul$ions,
+within five Minutes from the beginning
+of the Pumping.
+<p>A while after we put in a Mou$e, new-
+ly taken, in $uch a Trap as had rather af-
+frighted then hurt him; vvhil'$t he vvas
+leaping up very high in the Receiver, vve
+fa$ten'd the Cover to it, expecting that
+an Animal u$ed to live in narrow holes
+vvith very little fre$h Air, vvould endure
+the vvant of it better then the lately men-
+tion'd Birds: But though, for a vvhile af-
+ter the Pump vvas $et avvork, he conti-
+nued leaping up as before; yet 'tvvas not
+long ere he began to appear $ick and gid-
+dy, and to $tagger, after vvhich he fell
+dovvn as dead, but vvithout $uch violent
+Convul$ions as the Birds died vvith.
+Whereupon, ha$tily turning the Key, we
+let in $ome fre$h Air upon him, by vvhich
+he recovered, after a vvhile, his $en$es and
+his feet, but $eem'd to continue vveak and
+$ick: But at length, grovving able to
+skip as formerly, the Pump vvas plyed
+again for eight minutes, about the mid-
+dle of vvhich $pace, if not before, a very
+little Air by a mi$chance got in at the
+Stop-cock; and about tvvo minutes after
+that, the Mou$e divers times leap'd up
+<pb n=331>
+lively enough, though after about two mi-
+nutes more he fell down quite dead, yet
+with Convul$ions far milder then tho$e
+wherewith the two Birds expired. This
+alacrity $o little before his death, and his
+not dying $ooner then at the end of the
+eighth minute, $eem'd a$cribable to the
+Air (how little $oever) that $lipt into the
+Receiver. For the fir$t time, tho$e Con-
+vul$ions (that, if they had not been $ud-
+denly remedied, had immediately di$-
+patch'd him) $ei$'d on him in $ix minutes
+after the Pump began to be $et awork.
+The$e Experiments $eem'd the more
+$trange, in regard, that during a great part of
+tho$e few minutes the Engine could but
+con$iderably rarefie the Air (and that too,
+but by degrees) and at the end of them
+there remain'd in the Receiver no incon-
+$iderable quantity; as may appear by what
+we have formerly $aid of our not being
+able to draw down Water in a Tube, with-
+in much le$s then a Foot of the bottom:
+with which we likewi$e con$ider'd, that by
+the ex$uction of the Air and inter$per-
+$ed Vapors, there was left in the Recei-
+ver a $pace $ome hundreds of times ex-
+ceeding the bigne$s of the Animal, <*>e-
+ceive the fuliginous Steams, from which,
+<pb n=332>
+expiration di$charges the Lungs; and,
+which in the other ca$es hitherto known,
+may be $u$pected, for want of room, to
+$tifle tho$e Animals that are clo$ely pent
+up in too narrow Receptacles.
+<p>I forgot to mention, that having cau$'d
+the$e three Creatures to be open'd, I
+could, in $uch $mall Bodies, di$cover lit-
+tle of what we $ought for, and what we
+might po$$ibly have found in larger Ani-
+mals; for though the Lungs of the Birds
+appear'd very red, and as it were inflam'd,
+yet that colour being u$ual enough in the
+Lungs of $uch winged Creatures, de$erves
+not $o much our notice, as it does, That
+in almo$t all the de$tructive Experiments
+made in our Engine, the Animals appear'd
+to die with violently Convul$ive Moti-
+ons: From which, whether Phy$icians can
+gather any thing towards the Di$covery
+of the Nature of Convul$ive Di$tem-
+pers, I leave to them to con$ider.
+<p>Having proceeded thus far, though (as
+we have partly intimated already) there
+appear'd not much cau$e to doubt, but
+that the death of the fore-mention'd Ani-
+mals proceeded rather from the want of
+Air, then that the Air was over-clogg'd
+by the $teams of their Bodies, exqui$ite-
+<pb n=333>
+ly pent up in the Gla$s; yet I, that love
+not to believe any thing upon Conje-
+ctures, when by a not over-difficult Ex-
+periment I can try whether it be True or
+no, thought it the $afe$t way to obviate
+Objections, and remove Scruples, by $hut-
+ting up another Mou$e as clo$e as I could
+in the Receiver, wherein it liv'd above
+three quarters of an hour; and might pro-
+bably have done $o much longer, had not
+a <I>Virtuo$o</I> of quality, who in the mean
+while chanc'd to make me a Vi$it, de$ir'd
+to $ee whether or no the Mou$e could be
+kill'd by the ex$uction of the ambient Air,
+whereupon we thought fit to open, for a
+little while, an intercour$e betwixt the
+Air in the Receiver, and that without it,
+that the Mou$e might thereby (if it were
+needful for him) be refre$h d, and yet we
+did this without uncementing the Cover
+at the top, that it might not be objected,
+that perhaps the Ve$$el was more clo$ely
+$topp'd for the ex$uction of the Air then
+before.
+<p>The Experiment had this event, that
+after the Mou$e had liv'd ten Minutes,
+(which we a$crib'd to this, that the Pump,
+for want of having been lately Oyl'd,
+could move but $lowly, and could not by
+<pb n=334>
+him that manag'd it, be made to work as
+nimbly as it was wont) at the end of that
+time he dy'd with Convul$ive Fits, where-
+in he made two or three bounds into the
+Air, before he fell down dead.
+<p>Nor was I content with this, but for
+Your Lord$hips further $atisfaction, and
+my own, I cau$'d a Mou$e, that was very
+hungry, to be $hut in all Night, with a
+Bed of Paper for him to re$t upon: And
+to be $ure that the Receiver was well
+clo$'d, I cau$'d $ome Air to be drawn out
+of it, whereby, perceiving that there
+was no $en$ible leak, I pre$ently re-ad-
+mitted the Air at the Stop-cock, le$t the
+want of it $hould harm the little Animal;
+and then I cau$'d the Engine to be kept
+all Night by the Fire $ide, to keep him
+from being de$troy'd by the immoderate
+cold of the Fro$ty Night. And this care
+$ucceeded $o well, that the next Morning
+I found that the Mou$e not onely was a-
+live, but had devour'd a good part of the
+Chee$e that had been put in with him. And
+having thus kept him alive full twelve
+hours, or better, we did, by $ucking out
+part of the Air, bring him to droop, and
+to appear $well'd; and by letting in the
+Air again, we $oon reduc'd him to his for-
+mer liveline$s.
+<pb n=335>
+<C><I>A Digre$sion containing $ome
+Doubts touching Re$pi-
+ration.</I></C>
+<p>I Fear Your Lord$hip will now expect,
+that to the$e Experiments I $hould add
+my Reflections on them, and attempt,
+by their a$$i$tance, to re$olve the Diffi-
+culties that occur about Re$piration; $ince
+at the beginning I acknowledg'd a further
+Enquiry into the Nature of that, to have
+been my De$ign in the related Tryals.
+But I have yet, becau$e of the inconve-
+nient Sea$on of the Year, made $o few
+Experiments, and have been $o little $a-
+tisfied by tho$e I have been able to make,
+that they have hitherto made Re$piration
+appear to me rather a more, then a le$s
+My$terious thing, then it did before. But
+yet, $ince they have furni$h'd me with
+$ome $uch new Con$iderations, concern-
+ing the u$e of the Air, as confirms me in
+my Diffidence of the Truth of what is
+commonly believ'd touching that matter;
+That I may not appear $ullen or lazy, I
+am content not to decline employing a
+<pb n=336>
+few hours in $etting down my Doubts, in
+pre$enting Your Lord$hip $ome Hints,
+and in con$idering whether the Tryals
+made in our Engine, will at lea$t a$$i$t us
+to di$cover wherein the Deficiency lies
+that needs to be $upply'd.
+<p>And this, My Lord, being all my pre-
+$ent De$ign, I $uppo$e You will not ex-
+pect that (as if You knew not, or had for-
+gotten what Anatomi$ts are wont to
+teach) I $hould entertain You with a need-
+le$s Di$cour$e of the Organs of Re$pira-
+tion, and the variety of their Structure in
+$everal Animals; though if it were ne-
+ce$$ary, and had not been perform'd by o-
+thers, I $hould think, with <I>Galen,</I> that by
+<MARG><I>Galen<*> de
+<*>, Part:
+<*></I> 3.</MARG>
+treating of the Fabricks of living Bodies,
+I might compo$e Hymns to the wi$e Au-
+thor of Nature, who, in the excellent con-
+trivance of the Lungs, and other parts of
+(tho$e admirable Engines) Animals, ma-
+nife$ts him$elf to be indeed what the Elo-
+quent Prophet mo$t ju$tly $peaks him,
+<I>Wonderful in Counsel, and excellent in</I>
+<MARG><*>a.28.29.</MARG>
+<I>working.</I>
+<p>Nor $hall we any further meddle with
+tho$e Controver$ies $o much agitated a-
+mong the Moderns, namely, <I>Whether the
+motion of the Lungs in Re$piration be their</I>
+<pb n=337>
+<I>own, or but con$equent to the motion of the
+Thorax, Diaphragme, and</I> (as $ome Learn-
+ed Men would have it) <I>the Abdomen; And,
+Whence it is that the Air $wells the Lungs
+in In$piration</I> any further then they may
+receive light from our Engine: But that
+it may appear what kinde of $ervice it is
+that may be expected from it on this oc-
+ca$ion, we mu$t premi$e a few Words to
+$hew wherein the $trength of the Obje-
+ction we are to an$wer, lies. In favor then
+of tho$e that would have the Lungs ra-
+ther pa$$ive then active in the bu$ine$s of
+Re$piration, it may again$t the common
+opinion be alledg'd, That as the Lungs be-
+ing de$titute of Mu$cles and of Fibres,
+are unfit to dilate them$elves; $o it ap-
+pears, that without the motion of the
+<I>Thorax</I> they would not be fill'd with Air.
+Since as our Learned Friend Dr. <I>High-
+more</I> has well (and congruou$ly, to what
+our $elves have purpo$ely try'd) ob-
+$erv'd, if a live Dog have a great wound
+made in his Che$t, the Lobes of the
+Lungs on that $ide of the <I>Media$ti-
+num</I> will $ub$ide and lie $till; the <I>Tho-
+rax</I> and the Lobes on the other $ide
+of the <I>Media$tinum,</I> continuing their
+former motion. And if $uddenly at once
+<pb n=338>
+the Mu$cles of the Che$t be on both
+$ides di$$ected, upon the Ingre$s of the
+Air, the whole Lungs, though untouch'd,
+will remain movele$s, at lea$t, as to any ex-
+pan$ion or contraction of their $ub$tance.
+<p>To which we may adde the Ob$ervati-
+on of the diligent <I>Bartholinus,</I> who af-
+firms the like of the <I>Diaphragme</I> al-
+$o, namely, That it being wounded, the
+Lungs will fall together, and the Re$pi-
+ration cea$e, which my Experiments op-
+po$e not, provided the Wound be any
+thing great. And indeed the <I>Diaphragme</I>
+$eems the principal In$trument of ordina-
+ry and gentle Re$piration, although to
+re$train'd Re$piration (if I may $o call
+it) the interco$tal Mu$cles, and perhaps
+$ome others may be allowed eminently to
+concur. But the chief of the Contro-
+ver$ies formerly pointed at, is not yet de-
+cided, namely, what it is that conveys the
+Air into the Lungs. For when, to coun-
+terballance all that has been alledg'd, tho$e
+that plead for the Lungs, demand what it
+is that $hould bring the Air into the
+Lungs, if them$elves do not attract it,
+their Antagoni$ts di$agree about the Re-
+ply. For when to this que$tion $ome of
+the be$t Modern Philo$ophers an$wer,
+<pb n=339>
+that by the dilatation of the Che$t the
+contiguous Air is thru$t away, and that
+pre$$ing upon the next Air to it, and $o
+onwards, the Propul$ion is continued till
+the Air be driven into the Lungs, and $o
+dilate them: When this (I $ay) is an-
+$wered, it is Objected even by <I>Bartholine</I>
+him$elf, as a convincing Reply, that, ac-
+cording to this Doctrine, a Man could not
+fetch his Breath from a great Ve$$el full of
+Air, with a $lender Neck, becau$e, that
+when his Mouth covers the Orifice of the
+Neck, the dilatation of his <I>Thorax</I> could
+not propell the Air in the Ve$$el into his
+Lungs, by rea$on of its being $eparated
+by the inclo$ing Ve$$el from the ambient
+Air; and yet, $ay they, Experience wit-
+ne$$es that out of $uch a Ve$$el a Man may
+$uck Air. But of this difficulty our Engine
+furni$hes us with an ea$ie Solution, $ince
+many of the former Experiments have ma-
+nife$ted, That in the ca$e propo$ed, there
+needs not be made any (though 'tis true
+that in ordinary Re$piration there is wont
+to be made $ome) propul$ion of the Air by
+the $welling <I>Thorax</I> or <I>Abdomen</I> into the
+Lungs; $ince upon the bare Dilatation of
+the <I>Thorax,</I> the Spring of that internal
+Air, or halituous $ub$tance that is wont
+<pb n=340>
+to po$$e$s as much of the Cavity of the
+Che$t as the Lungs fill not up, being much
+weaken'd, the external and contiguous
+Air mu$t nece$$arily pre$s in at the open
+Winde-Pipe into the Lungs, as finding
+there le$s re$i$tance then any where el$e a-
+bout it.
+<p>And hence (by the way) we may derive
+a new a$$i$tance to judge of that famous
+Controver$ie di$puted among Naturali$ts
+and Phy$itians, ever $ince <I>Galens</I> time,
+$ome maintaining that the Che$t, with the
+contained Lungs, may be re$embled to a
+pair of Bellows, which comes therefore
+to be fill'd becau$e it was dilated: And o-
+thers pleading to have the compari$on
+made to a Bladder, which is therefore di-
+lated becau$e it is fill'd. For as to the
+<I>Thorax,</I> it $eems evident from what has
+been lately $aid, that it, like a pair of Bel-
+lows, happens to be partly fill'd with Air,
+but becau$e it was dilated: But as for the
+Lungs them$elves, who want Fibres to
+di$tend them, they may fitly enough be
+compar'd to a Bladder; $ince they are di-
+lated by being fill'd, namely, by that Air
+which ru$hes into them upon the dilatation
+of the Che$t, in who$e increa$ed Cavity
+it findes (as we fre$hly noted) le$s re$i$t-
+<pb n=341>
+ance to its Spring then el$ewhere. And
+this brings into my minde that $trange
+Ob$ervation of <I>Nicolaus Fontanus,</I> a Phy-
+<MARG><I>Fontan<*>
+apud</I> <*>
+tholin<*>
+cap. 9.</MARG>
+$itian at <I>Am$terdam,</I> who te$tifies, That
+in a Boy of the $ame Town, four years
+old, there was found, in$tead of Lungs, a
+certain Membranous Bladder; which be-
+ing fill'd with Wind, and furni$h'd with
+little Veins, had its origination from the
+Wind-Pipe it $elf; which being $uppo$'d
+true, how well it will agree with mo$t of
+the Opinions touching Re$piration, I leave
+to be con$idered.
+<p>And thus may the grand Objection of
+<I>Bartholine,</I> and others, be an$wered: But
+I leave to Anatomi$ts to con$ider what is
+to be $aid to $ome Ob$ervations that $eem
+to contradict tho$e Anatomical Experi-
+ments already mention'd: Such was par-
+ticularly that which I remember I have
+read in <I>Sennertus</I> (from the ob$ervation of
+his Father-in-law <I>Schato</I>) of a Melancho-
+ly Student, who having $tabb'd him$elf,
+and pierced the <I>Diaphragme</I> in the thinner
+or tendonous part (call'd by many the
+Nervous Circle) lived $even Moneths af-
+ter he had $o wounded him$elf, though af-
+ter his death (preceded by violent Vomit-
+<pb n=342>
+ings) the Wound (perchance dilated by
+tho$e $trainings) appear'd $o great, that
+the whole Stomack was found to have got
+in by it into the left $ide of the <I>Thorax.</I>
+And $uch al$o was the accident that hap-
+pen'd to a Noble Man, whom I remem-
+ber I have $een, and who is yet alive, in
+who$e Che$t there has, for the$e many
+years, remain'd a hole $o great, that the
+motion of his Heart may be perceiv'd by
+it. The$e (I $ay) and $ome other Ob$er-
+vations, I $hall now forbear to in$i$t on,
+becau$e I hold it not unfit, before we
+come to con$ider the u$e of Re$piration,
+that we acquaint Your Lord$hip with an
+Ingenious Conjecture, that was made at
+the cau$e of the ha$ty death of the Ani-
+mals our Engine kill'd: namely, That it
+was not the want of Air that de$troy'd
+them, but the Pre$$ure of the innate Air
+in the cavity of the Che$t; as if the
+Spring of this Air being no longer coun-
+terballanc'd by the ambient Air, was there-
+by become $o $trong, that it kept the
+<I>Thorax</I> forcibly di$tended, and hinder'd its
+wonted contraction; and $o compre$$'d
+the Lungs and their Ve$$els, as to ob$truct
+the Circulation of the Blood. And this
+<pb n=343>
+Conjecture, as it is $pecious enough, $o I
+might have admitted it for true; but that
+I con$ider'd, that (not to mention that
+one, e$pecially of the Animals kill'd in
+our Engine, $eem'd manife$tly for a pret-
+ty while, and not long before he dy'd, to
+move his <I>Thorax,</I> as if he exerci$'d Re$pi-
+ration) the diligent <I>Wall&aelig;us</I> relates, That
+he divers times ob$erv'd, in the Di$$ecti-
+on of live Bodies, that the Membrane
+that inve$ts the Lungs, had Pores in it
+as big as the larger $ort of Peas, which a-
+grees with the Ob$ervations of Chyrur-
+gions and Phy$itians, <I>viz.</I> That matter
+collected in the <I>Thorax,</I> has penetrated in-
+to the Lungs, and been di$charged by
+coughing. And I remember too, that mo$t
+of the Animals we kill'd in our Engine
+were Birds, of who$e Lungs <I>Harvey</I>
+$omewhere informs us, That he ob-
+$erv'd them very manife$tly to open at
+their Extremities into the <I>Abdomen.</I>
+And by $uch Perforations we may well
+$uppo$e the pa$$age free betwixt the exter-
+nal Air and that in the <I>Abdomen:</I> But this
+Conjecture may be further con$ider'd.
+Be$ides, to $how that the Animals that
+died in our Gla$$es, need not be $uppo$'d
+<pb n=344>
+to have been kill'd by the want of Air, we
+fore$ee another Argument that we mu$t
+deal $o ingeniou$ly with Your Lord$hip,
+as not to conceal. You very well know,
+that be$ides the generality of the
+Schools, there are many new Philo$ophers
+who, though they di$$ent from the old
+Peripateticks in other things, do, as they,
+deny the po$$ibility of a <I>Vacuum;</I> and
+hold, that tho$e $paces which are devoid
+of Air, and other gro$$er Bodies, are all
+of them exactly repleni$hed with a certain
+Etherial Matter, $o thin and $ubtle, that
+it can freely permeate the Pores of the
+compacted$t and clo$e$t Bodies, and ev'n
+of Gla$s it $elf. Now $ome of tho$e Na-
+turali$ts that are of this per$wa$ion may
+object, That the Animals that died in our
+Receivers, did $o, not $o much for lack of
+Air, as by rea$on that the Air that was
+pump'd out was nece$$arily $ucceeded by
+an Etherial Sub$tance; which con$i$ting of
+parts vehemently agitated, and $o very
+$mall, as without re$i$tance to pa$s in and
+out through the very Pores of Gla$s; it
+may well be $uppo$'d, that a con$iderable
+quantity of this re$tle$s and $ubtle Mat-
+ter, meeting together in the Receiver,
+<pb n=345>
+with the exce$$ive heat of it, may be
+quickly able to de$troy a little Animal, or
+at lea$t, make the Air too intemperately
+hot to be fit for Re$piration.
+<p>But though this be a Difficulty not $o
+ea$ily to be re$olv'd without the a$$i$tance
+of our Engine, yet I $uppo$e we have al-
+ready an$wer'd the Objection by our 38<SUP>th</SUP>
+and 39<SUP>th</SUP> Experiments; which though we
+made partly for other purpo$es, yet we
+premi$'d them onely to clear up the diffi-
+culty propo$'d.
+<p>Another $u$pition we $hould have en-
+tertain'd concerning the death of our Ani-
+mals, namely, That upon the $udden re-
+moval of the wonted pre$$ure of the am-
+bient Air, the warm Blood of tho$e Ani-
+mals was brought to an Efferve$cence or
+Ebullition, or at lea$t $o vehemently ex-
+panded, as to di$turb the Circulation of
+the Blood, and $o di$order the whole Oe-
+conomy of the Body. (This (I $ay) I
+$hould have had $ome $u$pition of) but
+that Animals of a hot Con$titution are
+not the $ole ones that cannot in our ex-
+hau$ted Engine exerci$e the Function of
+Life. But I mu$t not now dwell upon
+matters of this nature, becau$e I think
+it high time to proceed to the con$iderati-
+<pb n=346>
+on of the principal $ubject of our Engine,
+namely, The u$e of Re$piration; or ra-
+ther, The u$e of the Air in Re$piration.
+For whereas of the divers u$es of it men-
+tion'd by Anatomi$ts the mo$t, $uch as
+the Production and Modulation of the
+Voice by the Eli$ion of the Air, the <I>La-
+rynx</I> &amp;c. the expul$ion of Excrements
+by Coughing, the conveying in of Odours
+by In$piration, and $ome others, rather
+convenient for the well being of an Ani-
+mal, then ab$olutely nece$$ary to his Life:
+Whereas (I $ay) the other u$es are $uch as
+we have $aid, The great <I>Hippocrates</I> him-
+$elf gives this notable Te$timony to the
+u$e of the Air, as to Animals endow'd
+with Lungs, <I>Mortalibus</I> ($ays he) <I>hic</I> ($pi-
+ritus) <I>tum vit&aelig;, tum morborum &aelig;grotis cau-
+$a e$t. Tant&aacute;que corporibus omnibus $pi-
+rit&ucirc;s ine$t nece&szlig;itas, ut $iquidem aliis om-
+nibus &amp; cibis &amp; potionibus, quis <*>b$tineat,
+duos tam&etilde; aut tres, vel plures dies po&szlig;it vi-
+tam ducere: At $i quis $piritus in corpus
+vias intercipiat, vel exigu&acirc; diei parte, he-
+mini pereundum $it; Adeo nece$$arius e$t
+u$us $pirit&ucirc;s in corpore. Ad h&aelig;c quo&queacute;,
+quum omnibus aliis actionibus homines qui-
+e$cant, quod mutationibus innumer is vita
+$it expo$ita, ab h&acirc;c tamen $ol&acirc; actione nun-</I>
+<pb n=347>
+<I>quam de$i$tant animantia, quin aut $piritum
+adducant, aut reddant.</I>
+<p>But touching the account upon which
+the In$piration and Ex$piration of Air
+(both which are comprehended in <G>a)gapno<*></G>,
+Re$piration) is $o nece$$ary to Life, both
+Naturali$ts and Phy$itians do $o di$agree,
+that it will be very difficult either to re-
+concile their Opinions, or determine their
+Controver$ies.
+<p>For fir$t, Many there are who think
+the chief (if not $ole) u$e of Re$piration
+to be the Cooling and tempering of that
+Heat in the Heart and Blood, which other-
+wi$e would be immoderate: And this O-
+pinion, not onely $eems to be mo$t recei-
+ved among$t Schola$tick Writers, but di-
+vers of the new Philo$ophers, Carte$ians,
+and others, admitted with $ome variation;
+teaching, That the Air is nece$$ary, by its
+coldne$s, to conden$e the Blood that pa$-
+$es out of the right Ventricle of the
+Heart into the Lungs, that thereby it may
+obtain $uch a con$i$tence, as is requi$ite
+to make it fit Fewel for the vital Fire or
+Flame, in the left Ventricle of the heart.
+And this Opinion $eems favor'd by this,
+That Fi$hes, and other cold Creatures,
+who$e Hearts have but one cavity, are al-
+<pb n=348>
+$o unprovided of Lungs, and by $ome o-
+ther con$iderations. But though it need
+not be deny'd, that the in$pir'd Air may
+$ometimes be of u$e by refrigerating the
+Heart; yet (again$t the Opinion that makes
+this Refrigeration, the mo$t genuine and
+con$tant u$e of the Air) it may be Obje-
+cted, That divers cold Creatures ($ome
+of which, as particularly Frogs, live in
+the Water) have yet need of Re$piration,
+which $eems not likely to be needed for
+Refrigeration by them that are de$titute of
+any $en$ible heat, and be$ides, live in the
+cold Water: That even decrepid old
+Men, who$e natural heat is made very
+languid, and almo$t extingui$h'd by rea-
+$on of age, have yet a nece$$ity of fre-
+quent Re$piration: That a temperate Air
+is fitte$t for the generality of breathing
+Creatures; and as an Air too hot, $o al-
+$o an Air too cold, may be inconvenient
+for them (e$pecially, if they be troubled
+with an immoderate degree of the $ame
+Quality which is predominant in the Air:)
+That in $ome Di$ea$es the natural heat is
+$o weaken'd, that in ca$e the u$e of Re$pi-
+ration were to cool, it would be more
+hurtful then beneficial to breath; and the
+$u$pending of the Re$piration, may $up-
+<pb n=349>
+ply the place of tho$e very hot Medicines
+that are wont to be employ'd in $uch Di-
+$tempers: That Nature might much bet-
+ter have given the Heart but a moderate
+heat, then $uch an exce$$ive one, as needs
+to be perpetually cool'd, to keep it from
+growing de$tructive; which the gentle,
+and not the burning heat of an Animals
+Heart, $eems not inten$e enough $o indi-
+$pen$ably to require. The$e, and other
+Objections, might be oppo$'d, and pre$$'d
+again$t the recited Opinion: But we $hall
+not in$i$t on them, but onely adde to
+them, That it appears not by our fore-
+going Experiments (I mean the 38<SUP>th</SUP> and
+39<SUP>th</SUP>) that in our exhau$ted Receiver,
+where yet Animals die $o $uddenly for
+want of Re$piration, the ambient Body is
+$en$ibly hotter then the common Air.
+<p>Other Learned Men there are, who will
+have the very $ub$tance of the Air to get
+in by the Ve$$els of the Lungs, to the
+left Ventricle of the Heart, not onely to
+temper its heat, but to provide for the
+generation of Spirits. And the$e alledge
+for them$elves the Authority of the An-
+tients, among whom <I>Hippocrates</I> $eems
+manife$tly to favor their Opinion; and
+both <I>Ari$totle</I> and <I>Galen</I> do $ometimes
+<pb n=350>
+(for methinks they $peak doubtfully e-
+nough) appear inclinable to it. But for
+ought ever I could $ee in Di$$ections, it is
+very difficult to make out, how the Air is
+convey'd into the left Ventricle of the
+Heart, e$pecially the <I>Sy$tole</I> and <I>Dia$tole</I>
+of the Heart and Lungs, being very far
+from being Synchronical: Be$ides, that
+the Spirits $eeming to be but the mo$t
+$ubtle and unctuous Particles of the
+Blood, appear to be of a very differing
+Nature from that of the lean and incom-
+bu$tible Corpu$cles of Air. Other Ob-
+jections again$t this Opinion have been
+propo$'d, and pre$t by that excellent Ana-
+tomi$t, and my Indu$trious Friend, Dr.
+<I>Highmore,</I> to whom I $hall therefore refer
+you.
+<p>Another Opinion there is touching Re-
+$piration, which makes the genuine u$e of
+it to be Ventilation (not of the Heart,
+but) of the Blood, in its pa$$age thorow
+the Lungs; in which pa$$age, it is di$-
+burthened of tho$e Excrementitious
+Steams, proceeding, for the mo$t part,
+from the $uperfluous Sero$ities of the
+Blood, (we may adde) and of the <I>Chyle</I>
+too, which (by tho$e new Conduits of
+late very happily detected by the famous
+<pb n=351>
+<I>Pecquet</I>) hath been newly mix'd with it in
+the Heart.) And this Opinion is that of
+the Indu$trious <I>M&oelig;bius,</I> and is $aid to
+have been that of that excellent Philo$o-
+pher <I>Ga$$endus;</I> and hath been in part an
+Opinion almo$t vulgar: But this <I>Hypo-
+the$is</I> may be explicated two ways: For
+fir$t, The nece$$ity of the Air in Re$pi-
+ration, may be $uppo$'d to proceed from
+hence; That as a Flame cannot long burn
+in a narrow and clo$e place, becau$e the
+Fuliginous Steams it unce$$antly throws
+out, cannot be long receiv'd into the am-
+bient Body; which after a while growing
+too full of them, to admit any more, $ti-
+fles the flame, $o that the vital Fire in the
+Heart requires an ambient Body, of a
+yielding nature, to receive into it the $u-
+perfluous Sero$ities and other Recrements
+of the Blood, who$e $ea$onable Expul$i-
+on is requi$ite to depurate the Ma$s of
+Blood, and make it fit both to Circulate;
+and to maintain the vital heat re$iding in
+the Heart. The other way of explicating
+the above-mention'd <I>Hypothe$is,</I> is, by
+$uppo$ing, that the Air does not onely, as
+a Receptacle, admit into its Pores the Ex-
+crementitious vapors of the Blood, when
+they are expell'd through the Wind-Pipe,
+<pb n=352>
+but does al$o convey them out of the
+Lungs, in regard that the in$pired Air,
+reaching to all the ends of the <I>A$pera Ar-
+teria,</I> does there a$$ociate it $elf with the
+Exhalations of the circulating Blood, and
+when tis exploded, carrys them away with
+it $elf, as we $ee that winds $peedily dry up
+the $urfaces of wet Bodies, not to $ay any
+thing of what we formerly ob$ervd touch-
+ing our Liquor, who$e fumes were $trange-
+ly elevated upon the Ingre$s of the Air.
+<p>Now of the$e two ways of explicating
+the u$e of Re$piration, our Engine af-
+fords us this Objection again$t the fir$t;
+That upon the Ex$uction of the Air, the
+Animals die a great deal $ooner then if it
+were left in the Ve$$el; though by that
+Ex$uction the ambient $pace is left much
+more free to receive the $teams that are ei-
+ther breathed out of the Lungs of the
+Animal, or di$charg'd by in$en$ible Tran-
+$piration through the Pores of his
+Skin.
+<p>But if the <I>Hypothe$is</I> propo$'d, be taken
+in the other $en$e, it $eems congruous e-
+nough to that grand ob$ervation, which
+partly the <I>Ph&aelig;nomena</I> of our Engine, and
+partly the relations of Travellers, have
+$ugge$ted to us, namely, That there is a
+<pb n=353>
+certain con$i$tence of Air requi$ite to Re-
+$piration; $o that if it be too thick, and
+already over-charged with vapors, it will
+be unfit to unite with, and carry off tho$e
+of the Blood, as Water will di$$olve, and
+a$$ociate to it $elf but a certain proportion
+of $aline Corpu$cles; and if it be too
+thin or rarefied, the number or $ize of the
+A&euml;rial Particles is too $mall to be able to
+a$$ume and carry off the halituous Excre-
+ments of the Blood, in $uch plenty as is
+requi$ite.
+<p>Now that Air too much thicken'd (and
+as it were clogg'd) with Steams, is unfit
+for Re$piration, may appear by what is
+wont to happen in the Lead-Mines of <I>De-
+von$hire,</I> (and, for ought I know, in tho$e
+too of other Countrys, though I have
+$een Mines where no $uch thing was com-
+plain'd of) for I have been inform'd by
+more then one credible Per$on (and parti-
+cularly by an Ingenious Man, that has of-
+ten, for curio$ity, digg'd in tho$e Mines,
+and been imploy'd about them) that there
+often ri$es Damps, as retaining the <I>Ger-
+mane</I> Word by which they call them)
+which does $o thicken the Air, that unle$s
+the Work-men $peedily make $igns to
+them that are above, they would (which
+<pb n=354>
+al$o $ometimes happens) be pre$ently
+$tifled for want of Breath; and though
+their Companions do make ha$te to draw
+them up, yet frequently, by that time
+they come to the free Air, they are, as it
+were, in a $woon, and are a good while be-
+fore they come to them$elves again. And
+that this $wooning $eems not to proceed
+from any Ar$enical or Poy$onous Exhala-
+tion contain'd in the Damp, as from its
+over-much conden$ing the Air, $eems pro-
+bable from hence; That the $ame Damps
+oftentimes lei$urely extingui$h the flames
+of their Candles or Lamps; and from
+hence al$o that it appears (by many Rela-
+tions of Authentical Authors) that in
+tho$e Cellars where great $tore of new
+Wine is $et to work, men have been $uffo-
+cated by the too great plenty of the $teams
+exhaling from the Mu$t, and too much
+thickning the Air: as may be gathered
+from the cu$tom that is now u$ed in $ome
+hot Countrys, where tho$e that have oc-
+ca$ion to go into $uch Cellars, carry with
+them a quantity of well kindled Coals,
+which they hold near their Faces; where-
+by it comes to pa$s, that the Fire di$cu$-
+$ing the Fumes, and rarefying the Air re-
+duces the ambient Body to a con$i$tence fit
+for Re$piration.

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