ratione Erat longitudo sive altitudo camerae AH 5 Pedum Latitudine 3 ferè ex lateribus constructa in medio duo tenebat Diaphragmata CD EF in modum cribri pluribus foraminibus pertusi Paulo infra canalis G aquam advehens inserebatur in H eidem epistomium parabat exitum Aqua itaque per canalem G maximo impetu ruens vehementissimum ventum mox intus excitabat qui ventus nimiâ humiditate imbutus ut purior exiret sicciórque Diaphragmata illa in cribri modum pertusa ordinata sunt Intra haec enim aquae vehemens agitatio rupta fractáque Aerem puriorem per A canalem subtiliorémque emittebat Verum cum postea inventum sit Aerem plus aequo humidum interioribus Organi meatibus maximum detrimentum inferre Hinc ut Aer aquosus ficcissimam consistentiam acquireret ordinavimus canalem plumbeum QR in helicem contortum vasi S aliquantulum capaciori in modum Urnae efformato insertum Intra Urnam enim plumbeam canalem tortuosum illisus Aer humidus ita ab omni aquositate defaecabatur ut ex furno in Organum derivatus dici potuerit Urna S canalis tortuosi QR ultimum orificium Z inseritur anemothecae Organi Et hunc modum Organis hydraulicis omnium aptissimum reperi Debet autem camera illa situari in loco quantum fieri potest sicciori ita ut longo canali aqua intra eam derivetur ne locus humiditate suâ Organis officiat Thus far the Ingenious Kircherus whom I the rather cite because although I have been informed of divers Ventiducts as they call them by very knowing Travellers that have observ'd them yet this relation of our Author being very punctual and deliver'd upon his own particular Experience hath I confess made me with I had had the good fortune when I was at Rome to take notice of these Organs or that I had now the opportunity of examining of such an Experiment For if upon a strict enquiry I should find that the breath that blows the Organs doth not really upon the ceasing of its unusual agitation by little and little relapse into Water I should strongly suspect that 't is possible for Water to be easily turh'd into Air. I remember indeed that we have formerly taught that there lurks an interspersed Air in the pores of ordinary Water which may possibly be struck out by the breaking of the Water in its fall into the AEolian Chamber as he calls it But in regard the Scheme seems to represent that Chamber as closely shut and thereby forbids us to suppose that any Air is carried into it but what is latitant in the Water it will scarce seem probable to him who remembers how small a proportion of Air that appear'd to be when its rarefication ceased which was conceal'd in the Water we freed from bubbles in our Receiver that so little Air as is commonly dispers'd through Water should be able in so little Water as was requisite for so small a room to make so vehement a Wind as our Author here tells us of I have sometime therefore suspected that in this case the Wind may be produc'd by small particles of the Water it self forcibly expell'd out of the Chamber into the Organs And to the Objection to which I foresaw this ghess to be liable namely That no heat intervening there appear'd nothing that should raise the Water into exhalations and give them an impulse I thought it might be said that motion alone if vehement enough may without sensible heat suffice to break Water into very minute parts and make them ascend upwards if they can no where else more easily continue their agitation For I remember that travelling betwixt Lyons and Geneva I saw not very far out of the way a place where the River of Rhone comeing suddenly to be straiten'd betwixt two Rocks so near each other that a Man may if my Memory fail me not stand a stride upon both at once that rapid Stream dashing with great impetuosity against its Rocky Boundaries doth break part of its Water into such minute Corpuscles and put them into such a motion that Passengers observe at a good distance off as it were a Mist arising from that place and ascending a good way up into the Air. Such I say was my suspicion touching the Wind we have been considering but it seems something odd that aqueous Vapors should like a dry Wind pass through so long and tortuous a Pipe of Lead as that describ'd by our Authour since we see in the Heads of Stills and the Necks of AEolipiles how quickly such Vapors are even by a very little cold recondensed into Water But to this also something may be speciously reply'd wherefore contenting my self to have mention'd our Author's Experiment as a plausible though not demonstrative proof that Water may be transmuted into Air. We will pass on to mention in the third place another Experiment which we try'd in order to the same enquiry We took a clear glass Bubble capable of containing by guess about three Ounces of Water with a Neck somewhat long and wide of a Cylindrical form this we fill'd with Oyl of Vitriol and fair Water of each almost a like quantity and casting in half a dozen small Iron Nails we stopt the mouth of the Glass which was top full of Liquor with a flat piece of Diapalma provided for the purpose that accommodating it self to the surface of the Water the Air might be exquisitely excluded and speedily inverting the Viol we put the Neck of it into a small wide-mouth'd Glass that stood ready with more of the same Liquor in it to receive it As soon 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 bigness of a Pea which seem'd rather to consist of small and recent Bubbles produc'd by the action of the dissolving Liquor upon the Iron than any parcel of the external Air that might be suspected to have got in upon the inversion of the Glass especially since we gave time to those little Particles of Air which were carried down with the Nails into the Liquor to fly up again But whence this first Bubble was produced is not so material to our Experiment in regard it was so small For soon after we perceiv'd the Bubbles produc'd by the action of the Menstruum upon the Metal ascending copiously to the Bubble already named and breaking into it did soon exceedingly encrease it and by degrees depress the Water lower and lower till at length the substance contain'd in these Bubbles possessed the whole cavity of the glass Viol and almost of its Neck too reaching much lower in the Neck than the surface of the ambient Liquor where with the open-mouth'd Glass was by this means almost replenished And because it might be suspected that the depression of the
Liquor might proceed from the agitation whereinto the exhaling and imprison'd Steams were put by that heat which is wont to result from that action of corrosive salts upon Metals we suffered both the Viol and the open-mouth'd Glass to remain as they were in a Window for three or four days and nights together but looking upon them several times during that while as well as at the expiration of it the whole cavity of the glass Bubble and most of its Neck seem'd to be possess'd by Air since by its spring it was able for so long to hinder the expell'd and ambient Liquor from regaining its former place And it was remarkable that just before we took the glass Bubble out of the other Glass upon the application of a warm hand to the convex part of the Bubble the imprison'd substance readily dilated it self like Air and broke through the Liquor in divers bubbles succeeding one another Having also another time try'd the like Experiment with a small Viol and with Nails dissolv'd in Aquafortis we found nothing incongruous to what we have now deliver'd And this Circumstance we observ'd that the newly generated Steams did not onely possess almost all the whole cavity of the Glass but divers times without the assistance of the heat of my hand broke away in large bubbles through the ambient Liquor into the open Air So that these Experiments with corrosive Liquors seem'd manifestly enough to prove though not that Air may be generated out of the Water yet that in general Air may be generated anew Lastly To the foregoing Arguments from Experience we might easily subjoyn the Authority of Aristotle and of his Followers the Schools who are known to have taught that Air and Water being symbolizing Elements in the quality of moisture are easily transmutable into one another But we shall rather to the foregoing Argument add this drawn from Reason That if as Leucippus Democritus Epicurus and others follow'd by divers modern Naturalists have taught that the difference of Bodies proceeds but from the various Magnitudes Figures Motions and Textures of the small parts they consist of all the qualities that make them differ being deducible from thence there appears no reason why the minute parts of Water and other Bodies may not be so agitated or connected as to deserve the name of Air. For if we allow the Cartesian Hypothesis according to which as we noted at the beginning of this Letter the Air may consist of any terrene or aqueous Corpuscles provided they be kept swimming in the interfluent Celestial Matter it is obvious that Air may be as often generated as Terrestrial Particles minute enough to be carried up and down by the Celestial Matter ascend into the Atmosphere And if we will have the Air to be a congeries of little slender Springs it seems not impossible though it be difficult that the small parts of divers Bodies may by a lucky concourse of causes be so connected as to constitute such little Springs since as we note in another Treatise Water in the Plants it nourisheth is usually contriv'd into springy Bodies and even the bare alter'd position and connexion of the parts of a Body may suffice to give it a Spring that it had not before as may be seen in a thin and flexible Plate of Silver unto which by some strokes of a Hammer you may give a Spring and by onely heating it red-hot you may make it again flexible as before These My Lord are some of the Considerations at present occurring to my thoughts by which it may be made probable that Air may be generated anew And though it be not impossible to propose Objections against these as well as against what hath been represented in favour of the contrary Doctrine yet having already almost tired my self and I fear more than almost tired Your Lordship with so troublesome an Enquiry after the nature of Bubbles I shall willingly leave Your Lordship to judge of the Arguments alledged on either side and I should scarce have ventur'd to entertain You so long concerning such empty things as the Bubbles which have occasioned all this Discourse but that I am willing to invite You to take notice with me of the obscurity of things or the dimness of our created Intellects which yet of late too many so far presume upon as either to deny or censure the Almighty and Omniscient Creator himself and to learn hence this Lesson That there are very many Things in Nature that we disdainfully overlook as obvious or despicable each of which would exercise our Understandings if not pose them too if we would but attentively enough consider it and not superficially contemplate but attempt satisfactorily to explicate the nature of it EXPERIMENT XXIII SInce the writing of the twenty first and twenty second Experiments and notwithstanding all that hath been on their occasion deliver'd concerning Bubbles we made some farther trials in prosecution of the same inquiry whereto they were designed We chose then amongst those Glasses which Chymists are wont to call Philosophical Eggs one that containing about nine Ounces of Water had a Neck of half an Inch in Diameter at the top and as we guest almost an Inch at the bottom which breadth we pitched upon for a reason that will by and by appear then filling it up with common Water to the height of about a Foot and an half so that the upper part remained empty we shut it into the Receiver and watch'd what would follow upon pumping which proved that a great part of the Air being drawn out the Bubbles began to discover themselves at the bottom and sides of the Glass and increasing as the Air was more and more drawn away they did from time to time ascend copiously enough to the top of the Water and there quickly break but by reason that the wideness of the Glass allow'd them free passage through the Water they did not appear as in the former Experiments to make it swell The Water scarce ever rising at all above the mark affixt to its upper surface when it was put in and upon the return permitted to the outward Air and consequently the shrinking in of the remaining bubbles the Water seem'd to have lost of his first extent by the avolation of the formerly interspers'd Air. Being willing likewise to try whether distilled Water were by having been divided into minute parts and then re-united more or less dispos'd to expand it self than Water not distill'd We took out of our Laboratory some carefully distill'd rain-Rain-water and put about two Ounces of it into a round Glass-bubble with a very small Neck not exceeding the sixth part of an Inch in diameter which we filled half way to the top and then convey'd it into the Receiver the issue was that though we drew out more Air than ordinary yet there appeared not the least intumescence of the Water nor any ascending bubbles But suspecting that either the small quantity of the Water or
was thorowly wetted in fair Water that the sides of it being squeez'd together there might be no Air left in its folds as indeed we could not afterwards upon trial discern any The neck of this Bladder was strongly tied about that of a small Glass capable of holding five full drachmes of Water the Bladder being first so compress'd that all the included Air was only in the Glass without being press'd there then the Pump being set on work after a few exsuctions the Air in the little Viol began to dilate it self and produce a small Tumor in the neck of the Bladder and as the ambient Air was more and more drawn away so the included Air penetrated farther and farther into the Bladder and by degrees listed up the sides and display'd its folds till at length it seem'd to have blown it up to its full extent Whereupon the external Air being permitted to flow back into the Receiver repuls'd the Air that had fill'd the Bladder into its former narrow receptacle and brought the Bladder to be again flaccid and wrinkled as before Then taking out the Bladder but without severing it from the Glass we did by a hole made at the top of the Bladder fill the Vessel they both made up with Water whose weight was five Ounces five Drachmes and a half Five Drachmes whereof were above-mention'd to be the contents of the Bottle So that in this Experiment when the Air had most extended the Bladder it possess'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 sticking together of its sides did somewhat resist its expansion And which was more considerable the Bladder appear'd tumid enough whilst yet a pretty deal of Air was left in the Receiver whose exsuction would according to our former Observation probably have given way to a farther expansion of the Air especially supposing the dilatation not to be restrain'd by the Bladder SInce we wrote the other day the former Experiment we have met with some Glasses not very unfit for our purpose by means of which we are now able with a little more trouble to measure the expansion of the Air a great deal more accurately than we could by the help of the above-mention'd Bladder which was much too narrow to allow the Air its utmost distention We took then first a Cylindrical Pipe of Glass whose bore was about a quarter of an Inch in Diameter This Pipe was so bent and doubled that notwithstanding its being about two foot in length it might have been shut up into a smaller Receiver not a Foot high But by misfortune it crack'd in the cooling whereby we were reduced to make use of one part which was straight and intire but exceeded not six or seven Inches This little Tube was open at one end and at the other where it was Hermetically seal'd had a small Glass bubble to receive the Air whose dilatation was to be measur'd Along the side of this Tube was pasted a straight narrow piece of Parchment divided into twenty six equal parts marked with black Lines and Figures that by them might be measur'd both the included Air and its dilatation Afterwards we fill'd the Tube with Water almost to the top and stopping the open end with the Finger and inverting the Tube the Air was permitted to ascend to the above mention'd Glass bubble And by reason this ascent was very slow it gave us the opportunity to mark how much more or less than one of the twenty six divisions this Air took up By this means after a trial or two we were inabled to convey to the top of the Glass a bubble of Air equal enough as to sight to one of those Divisions Then the open end of the Tube being put into a small Viol whose bottom was cover'd with Water about half an Inch high we included both Glasses into a small and slender Receiver and caused the Pump to be set on work The event was That at the first exsuction of the Air there appear'd not any expansion of the bubble comparable to what appear'd at the second and that upon a very few exsuctions the bubble reaching as low as the surface of the subjacent Water gave us cause to think That if our Pipe had not been broken it would have expanded it self much farther Wherefore we took out the little Tube and found that besides the twenty six divisions formerly mention'd the Glass bubble and some part of the Pipe to which the divided Parchment did not reach amounted to six divisions more Whereby it appears that the Air hath take up one and thirty times as much room as before and yet seem'd capable of a much greater expansion if the Glass would have permitted it Wherefore after the former manner we let in another bubble that by our guess was but half as big as the former and found that upon the exsuction of the Air from the Receiver this little bubble did not only fill up the whole Tube but in part break through the subjacent Water in the Viol and thereby manifest it self to have prossessed sixty and odd times its former room These two Experiments are mention'd to make way for the more easy belief of that which is now to follow Finding then that our Tube was too short to serve our turn we took a slender Quill of Glass which happen'd to be at hand though it were not so fit for our purpose as we could have wished in regard it was three or four times as big at one end as the other This Pipe which was thirty Inches long being Hermetically seal'd at the slender end was almost filled with water and after the above-related manner a bubble was convey'd to the top of it and the open extreme was put into a Viol that had a little fair Water at the bottom Then the Cover by means of a small hole purposely made in it for the Glass Pipe to stand out at was cemented on to the Receiver and the Pump being set on work after some exsuctions not only the Air manifestly appear'd extended below the surface of the subjacent Water but one of the By-standers affirms that he saw some bubbles come out at the bottom of the Pipe and break through the Water This done we left off Pumping and observ'd how at the unperceiv'd leaks of the Receiver the Air got in so fast that it very quickly impell'd up the Water to the top of the Tube excepting a little space whereinto that bubble was repuls'd which had so lately possess'd the whole Tube this Air at the slender end appear'd to be a Cylinder of â…š parts of an Inch in length but when the Pipe was taken out and turn'd upside down it appear'd at the other end inferiour in bulck to a Pea. These things being thus done we took to make the Experiment the more exactly a small pair of
Scales such as Gold-Smiths use to weigh Cold Coyn in and weighing the Tube and Water in it we found them to amount to one Ounce thirty Grains and an half Then we pour'd in as much Water as serv'd to fill up the Tube wherein before we had left as much space unfill'd up as was possess'd by the bubble and weighing again the Pipe and Water we found the weight increas'd onely by one Grain Lastly pouring out the Water and carefully freeing the Pipe from it which yet we could not perfectly doe we weighed the Glass 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 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 was so rarified as to take up one hundred fifty two times as much room as it did before Though it were then compress'd by nothing but the ordinary pressure of the contiguous Air. I know not whether it be requisite to take notice that this Experiment was made indeed in a moist Night but in a Room in whose Chimney there was burning a good Fire which did perhaps somewhat rarifie the Air of which the bubble consisted It hath seem'd almost incredible which is related by the Industrious Mersennus That the Air by the violence of heat though as great as our Vessels can support without fusion can be so dilated as to take up seventy times as much room as before Wherefore because we were willing to have a confirmation of so strange a Phaenomenon we once more convey'd into the Tube a bubble of the bigness of the former and prosecuting the Experiment as before with the same Water we observed that the Air did manifestly stretch it self so far as to appear several times a good way below the surface of the Water in the Viol and that too with a surface very convex toward the bottom of the Pipe Nay the Pump being ply'd a little longer the Air did manifestly reach to that place where the bottom of the Tube leaned upon the bottom of the Viol and seemed to knock upon it and rebound from it Which Circumstances we add partly that the Phaenomenon we have been relating may not be imputed to the bare subsiding of the Water that filled the Tube upon the taking off the pressure of the ambient Air. And partly also that it may appear that if our Experiments have not been so accurately made as with fitter Instruments might perhaps be possible yet the expansion of the Air is likely to be rather greater than lesser than we have made it Since the Air was able to press away the Water at the bottom of the Pipe though that were about two Inches below the surface of the Water that was then in the Viol and would have been at least as high in the Pipe if the Water had onely subsided and not been depressed So that it seems not unlikely that if the Experiment could be so made as that the expansion of the Air might not be resisted by the Neighbouring Bodies it would yet enlarge its bounds and perhaps stretch it self to two hundred times its former bulk if not more However what we have now tryed will I hope suffice to hinder divers of the Phaenomena of our Engine from being distrusted Since in that part of the Atmosphere we live in that which we call the free Air and presume to be so uncompressed is crouded into so very small a part of that space which if it were not hindred it would possess We would gladly have tryed also whether the Air at its greatest expansion could be farther rarified by heat but doe what we could our Receiver leaked too fast to let us give our selves any satisfaction in that particular EXPERIMENT VII TO discover likewise by the means of that pressure of the Air both the strength of Glass and how much interest the Figure of a Body may have in its greater or lesser Resistance to the pressure of other Bodies we made these farther tryals We caus'd to be blown with a Lamp a round Glass bubble capable of containing by guess about five Ounces of Water with a slender neck about the bigness of a Swan's Quill and it was purposely blown very thin as Viols made with Lamps are wont to be that the thinness of the matter might keep the roundness of the Figure from making the Vessel too strong Then having moderately emptied the Receiver and taken it out of the Pump we speedily applied to the Orifice of the bottom of it the Neck of the newly mention'd Glass carefully stopping the Crannies with melted Plaister that no Air might get in at them And after turning the Key of the Stop-cock we made a free passage for the Air to pass out of the bubble into the Receiver Which it did with great celerity leaving the bubble as empty as the Receiver it self as appear'd to us by some Circumstances not now to be insisted on Notwithstanding all which the Vessel continuing as intire as before gave us cause to wonder that the bare roundness of the Figure should enable a Glass almost as thin as Paper to resist so great a pressure as that of the whole incumbent Atmosphere And having reiterated the Experiment we found again that the pressure of the ambient Body thrusting all the parts inwards made them by reason of their arched Figure so support one another that the Glass remain'd as whole as at first Now that the Figure of the Glass is of great moment in this matter may be evinced by this other Experiment EXPERIMENT VIII WE took a Glass Helmet or Alembick delineated by the seventh Figure such as Chymists use in Distillations and containing by conjecture between two and three Pints The Rostrum or Rose of it mark'd with c was Hermetically closed and at the top of it was a hole into which was fitted and cemented one of the Shanks of a middle-siz'd Stop-cock so that the Glass being turn'd upside-down the wide Orifice which in common Glass-Helmets is the onely one was upwards and to that wide Orifice was fitted a cast cover of Lead which was carefully cemented on to the Glass Then the other Shank of the Stop-cock being with cement likewise fasten'd into the upper part of the Pump the exsuction of the Air was endeavoured But it was not long before the remaining Air being made much too weak to ballance the pressure of the Ambient Air the Glass was not without a great noise crack'd almost half round along that part of it where it began to bend inwards As if in the Figure the crack had been made according to the Line a b and upon an endeavour to pump out more of the Air the crack once begun appear'd to run on farther though the Glass where it was broken seem'd to be by conjecture above ten some thought above twenty times as thick as the bubble mentioned in the foregoing
the Bladder from swimming and no more For I suppos'd that if when all things were thus order'd the Receiver were empty'd in case there were any such pressure of the Atmosphere upon Water as I was inclin'd to believe the Air within the Bladder being upon the exsuction of the Air within the Receiver freed from that pressure and being press'd onely by the small weight of the incumbent Water would considerably expand it self but whilst we were preparing Bladders for this Experiment there occurr'd an easie way for the making at once both the Discoveries I desir'd We took then a Glass Viol containing by ghess a pound and some ounces of Water this we fill'd top full and then we put into the Neck of it a Glass Pipe a pretty deal bigger than a Goose Quill open at both ends and of divers Inches in length One end of this Pipe was so 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 any Water get out of it otherwise than through the Pipe and then the Pipe being warily fill'd about half way up to the top with more Water and a mark being pasted over aganst the upper surface of the Liquor the Viol thus fitted with the Pipe was by strings let down into the Receiver and according to the wonted manner exquisitely clos'd up in it 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 rise higher in the Pipe at the sides of which some little bubbles discover'd themselves After a little while longer the Water still swelling there appear'd at the bottom of the Pipe a bubble about the bigness of a small Pea which ascending through the Pipe to the top of the Water stay'd there a while and then broke but the Pump being nimbly ply'd the expansion of the Water so encreas'd that quickly getting up to the top of the Pipe some drops of it began to run down along the out-side of it which oblig'd us to forbear pumping a while and give the Water leave to subside within less than two Inches of the bottom of the Pipe After this the Pump being again set on work the bubbles began to ascend from the bottom of the Pipe being not all of a size but yet so big that estimating one with another they appear'd to be of the size of the smaller sort of Peas and of these we reckon'd about sixty which came up one after another besides store of smaller ones of which we made no reckoning And at length growing weary of reckoning and pumping too because we found that in spight of all our pains and industry some undiscern'd Leak or other in the Receiver hinder'd us from being able to empty it altogether we thought fit to desist for that time after tryal made of what operation the external Air being let in upon the expanded Water would have and accordingly turning the Key to let in the Air we saw as we expected that the Water in the Pipe in a moment fell down almost to the bottom of it Now of this Experiment there are two or three Circumstances yet to be mention'd which are no less than those already recited pertinent to our present purpose In the first place then when the greater part of the Air had been pump'd out of the Receiver the rising bubbles ascended so very slowly in the Pipe that their Progress was scarce discernable which seem'd to proceed from this That their bigness was such That they could not sufficiently extend themselves in the cavity of the Glass without pressing on both hands against the sides of it whereby they became of more difficult extrusion to the Water And though it may seem strange that these bubbles should be of any considerable bulk since 't is like they consisted of lesser parcels of the Air lurking in the Water than those that were vigorous enough to make their way through long before them yet they were commonly much larger than before some of them being equal in quantity to four or five Peas whether this their increase of bulk proceeded from the greater decrement of the pressure of the Air or from the Union of two or three of those numerous bubbles which were then generated below the bottom of the Pipe where we could not see what was done among them Another thing we noted in our bubbles was That whereas in ordinary ones the Air together with the thin film of Water that invests and detains it is wont to swell above the surface of the Water it swims on and commonly to constitute Hemispherical 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 such whose upper surface was either level with or beneath that of the Water so that the upper surface being usually somewhat convex the less protuberant parts of it had a pretty quantity of Water remaining above them We also farther observ'd that whereas in the bubbles that first appear'd in the Pipe the ascending Air did as in other common bubbles make its way upwards by dividing the Water through which it pass'd in those bubbles that appear'd at the latter end of our Experiment when the pressure of the little external Air remaining in the Receiver was grown inconsiderable the ascending parcels of Air having how little more than the weight of the incumbent Water to surmount were able both so to expand themselves as to fill up that part of the Pipe which they pervaded and by pressing every way against the sides of it to lift upwards with them what Water they found above them without letting any considerable quantity glide down along the sides of the Glass So that sometimes we could see a bubble thrust 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 noted upon the letting in the external Air these tumid bubbles suddenly relaps'd to their former inconspicuousness All these things laid together seem'd sufficiently to confirm that which the consideration of the thing it self would easily enough perswade namely That the Air and such like Bodies being under Water may be press'd upon as well by the Atmosphere as by the weight of the incumbent Water it self Hence likewise we may verify what we observ'd at the close of the foregoing Experiment namely That from the sole swelling of Water there recorded it cannot be so safely concluded that Water when freed from compression is endow'd with an Elastical power of expanding it self since thereby it appears that the Intumescence produc'd by that Experiment may at least in great part be ascribed to the numerous little bubbles which are wont to be produc'd in Water from which the pressure of the Atmosphere is in great measure taken off So apt are we to be mis-led
even by Experiments themselves into Mistakes when either we consider not that most Effects may proceed from various Causes or mind onely those Circumstances of our Experiment which seem to comply with our preconceiv'd Hypothesis or Conjectures And hence it seems also probable that in the Pores or invisible little recesses of Water it self there lie commonly interspers'd many parcels of either Air or at least something Analagous thereunto although so very small that they have not been hitherto so much as suspected to lurk there But if it be demanded how it appears that there is interspers'd through the Body of Water any substance thinner than it self and why that which produc'd the bubbles abovemention'd should not be resolutely said to be nothing else than a more active and spirituous part of the Water we shall in order to the Elucidation of this matter subjoyn to what was formerly deliver'd the following Experiment EXPERIMENT XXII WE recited in our ninteenth Experiment how by drawing most of the Air out of the Receiver we made the Water subside by degrees in a Glass not four Foot long We shall now add that in the like Experiment made in such a Tube or a greater it may be observ'd That when the Water begins to fall there will appear store of bubbles fasten'd all along to the sides of the Glass of which bubbles by the agitation of the Vessel consequent upon pumping there will arise good numbers to the top of the Water and there break and as the Cylinder of Water is brought to be lower and lower so the bubbles will appear more numerous in that part of the Tube which the Water yet fills and the nearer the surface of the Water in its descent approacheth to these bubbles the greater they will grow because having the less weight and pressure upon them the expansion of that Air which makes them can be the less resisted by the pressure of the incumbent Water and Air as seems probable from hence that upon the letting in a little external Air those bubbles immediately shrink It may indeed as we lately intimated be conjectur'd that these bubbles proceed not so much from any Air pre-existent in the Water and lurking in the Pores of it as from the more subtle parts of the Water it self which by the expansion allow'd them upon the diminish'd pressure of the ambient Bodies may generate such bubbles And indeed I am not yet so well satisfied that bubbles may not at least sometimes have such an origination but that which makes me suspect that those in our tryals contain real Air formerly latitant in the Pores of the Water 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 stopt in its ascent near an Inch beneath the top And since if the upper part of the Tube had been devoid of any other than such Ethereal matter as was subtle enough freely to penetrate the pores of the Glass the external Air would have been able to impel the Water to the top of a Tube seven or eight times as long as ours was The Phaenomenon under consideration seem'd manifestly 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 Glass from receding was able to with stand the pressure of the outward Air. As we see that if never so little Air remain in the Tube upon the making the Experiment De Vacuo with Quick-silver no inclining of the Tube though a long one will enable a Man to impell the Mercury up to the very top by reason as we formerly noted of the resistance of the included Air which will not be compress'd beyond a certain degree But in order to a farther discovery what our bubbles were we will on this occafion inform Your Lordship that we try'd the XIXth Experiment in one of our small Receivers and found that upon the drawing down of the Water so many bubbles disclos'd themselves and broke into the upper part of the Tube that having afterwards let in the external Air the Water was not thereby impell'd to the top of the Tube three Foot in length within a little more than half an Inch. And whether or no it were Air that possess'd that space at the top of the Tube which was not fill'd with Water we took this course to examine We drew the second time the Air out of the Receiver and found that by reason of the body that possess'd the top of the Tube we were able not onely to make the Water in the Tube fall to a level with the surface of the Water in the Vessel But also by plying the Pump a little longer a great way beneath it which since it could not well be ascrib'd to the bare subsiding of the Water by reason of its own weight argued that the Water was depress'd by the Air which was confirm'd by the Figure of the surface of the Water in the Tube which was much more concave than that of Water in Tubes of that bigness useth to be And this farther tryal to add that upon the bye we made at the same time That when the Water in the Pipe was drawn down almost as low as the Water without it we observ'd that though we desisted from pumping by the bare application of a hand moderately warm to the deserted part of the Tube the remaining Water would be speedily and notably depress'd And having for a while held a kindled Coal to the outside of the Tube the Pump being still unimploy'd because the Vessel chanced to hold extraordinarily well the Air was by the heat so far expanded that it quickly drove the Water to the bottom of the Tube which was divers Inches beneath the surface of the ambient Water Whereby it appears by the same way by which we formerly measur'd the dilatation of the Air that the Air even when it is expanded to between 90 and 100 times its extent will yet readily admit of a much farther rarefaction by heat I consider'd also that in case the Bubbles we have been speaking of were produc'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 pressure would not disclose bubbles as before and accordingly the Air being again pump'd out the Water in the Tube descended as formerly but for a great while we scarce saw one bubble appear onely when the Receiver had been very much exhausted and the Water was fallen very low there appear'd near the bottom of the Tube certain little bubbles which seem'd to consist of such parcels of Air as had not by reason of their smallness got up to the top of the Water with the more bulky and vigorous ones And that which is not inconsiderable is
the figure of the Vessel might have an interest in this odd Phaenomenon we took the lately mentioned Philosophical Egg and another not much differing from it the former we fill'd up with distill'd Rain-water to the old mark and into the latter we put a long Cylinder or Rod of solid Glass to straiten the cavity of the Neck by almost filling it up and then pouring some distilled Water into that also till it reach'd within some Fingers breadth of the top the Eggs were let down into the Receiver In this Experiment the Air was so far drawn forth before there appeared any bubble in either of the Glasses that the disparity betwixt this and common Water was manifest enough But at length when the Air was almost quite pump'd out the bubbles began to disclose themselves and to increase as the pressure of the Air in the Receiver decreas'd But whereas in the first mentioned Philosophical Egg the bubbles were very small and never able to swell the Water that we took notice of at all above the mark In the other whose Neck as we lately said was straitned and their passage obstructed great numbers of them and bigger fastned themselves to the lower end of the Glass-rammer if we may so call it and gather'd in such numbers between that and the sides of the Neek that the Water swell'd about a Finger's breadth above the mark though upon the admitting of the external Air it relapsed to the former mark or rather fell somewhat below it And although thereupon in the first named Vessel all the bubbles presently disappeared yet in the other we observed that divers remained fastned to the lower part of the Glass-rammer and continued there somewhat to our wonder for above an hour after but contracted in their dimentions Moreover having suffered the Glasses to remain above twenty four hours in the Receiver we asterwards repeated the Experiment to try what change the exsuction of the external Air would produce in the Water after the internal and latitant Air had as is above recited in great measure got away in bubbles and whether or no the Water would by standing re admit any new particles of Air in the room of those that had forsaken it But though we exhausted the Receiver very diligently yet we scarce saw a bubble in either of the Glasses not with standing which we perceiv'd the Water to rise about the breadth of a Barly-corn or more in the Neck of that Glass wherein the solid Cylinder had been put the Liquor in the other Glass not sensibly swelling And lastly upon the letting in of the Air the Water in the straitned Neck soon subsided to the mark above which it had swollen which whether it ought to be ascrib'd to the same small expansion of the parts of the Water it self or to the rarifaction of some yet latitant Air broken into such small particles as to escape our observation seems not easily determinable without such farther tryals as would perhaps prove tedious to be recited as well as to be made though I was content to set down those already mentioned that it might appear how requisite it is in nice Experiments to consider variety of Circumstances EXPERIMENT XXIV AFter having thus discovered what operation the exsuction of the ambient Air had upon Water we thought good to try also what changes would happen in other Liquors upon the like taking off the pressure of the external Air. We took then a glass Egg somewhat bigger than a Turkey Egg which had a long Neck or Stem of about a â…“ part of an Inch in diameter and filling it up with Sallet-oyl untill it reach'd above half way to the top of the Neck we inclos'd it in the Receiver together with common Water in a resembling Vessel that we might the better compare together the operation of the exsuction of the Air upon those two Liquors The Pump being set on work there began to appear bubbles in the Oyl much sooner than in the Water and afterwards they also ascended much more copiously in the former Liquor than in the latter Nay and when by having quite tired the Pumper and almost our own Patience we gave over the Bubbles rose almost if not altogether in as great numbers as ever insomuch that none of the various Liquors we tried either before or since seemed to abound more with Aerial Particles than did this Oyl In which it was farther remarkable that between the time it was set into the Receiver and that at which we could get ready to pump it subsided notably by ghess about half an Inch below the mark it reached before it was put in After this express'd Oyl we made tryal of a distill'd one and for that purpose made choice of the common Oyl or Spirit for in the Shops where it is sold the same Liquor is promiscuously called by either name of Turpentine because 't was onely of that Chymical Oyl we had a sufficient quantity which being put into a small glass Bubble with a slender Neck so as to fill it about two Inches from the top did upon the evacuating of the Receiver present us with great store of bubbles most of which rising from the bottom expanded themselves exceedingly in their ascent and made the Liquor in the Neck to swell so much by degrees that at length it divers times ran over at the top by which means we were hindred from being able to discern upon the letting in of the Air how much the subsidence of the Oyl below the first mark was due to the recess of the Bubbles Having likewise a mind to try whether as strong a solution of Salt of Tartar in fair Water as could be made we having then no Oyl of Tartar per deliquium at hand though it be accounted Quick-silver excepted the heaviest of Liquors would afford us any bubbles we put in a glass Egg full of it at the same time with other Liquors and found that they did long yield store of bubbles before any discovered themselves in the Liquor of Tartar and having pursued the Experiment it appear'd That of all the Liquors we made trial of this afforded the fewest and smallest bubbles Spirit of Vineger being tried after the same manner exhibited a moderate number of bubbles but scarce any thing else worth the mentioning Nor could we in Red Wine try'd in a glass Egg take notice of any thing very observable For though upon the exsuction of the Air the bubbles ascended in this Liquor as it were in sholes and shifted places among themselves in their ascent yet the intumescence of the whole bulk of the Liquor was scarce at all sensible the bubbles most commonly breaking very soon after their arrival at the top where during their stay they composed a kind of shallow froth which alone appeared higher in the Neck of the Glass than was the Wine when it was let down Neither yet did Milk conveyed into our Pneumatical Vessel present us with any thing memorable save
that as it seem'd by reason of some unctuousness of the Liquor the bubbles not easily breaking at the top and thrusting up one another made the Intumescence appear much greater than that of common Water We likewise conveyed Hens Eggs into the Receiver but after the exsuction 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 burst by freezing them within doors with Snow and Salt The Ice into which the aqueous parts of the Egg were turned by the cold so distending probably by reason of the numerous bubbles wont to be observable in Ice the outward parts of the Egg that it usually crack'd the Shell though the inner Membrane that involv'd the several Liquors of the Egg because it would stretch and yield remain'd unbroken And hereupon we imagin'd that in our Engine it might appear whether or no there were any considerable Spring either in any of the Liquors or in any other more spirituous substance included in the Egg. We took also some Spirit of Urine carelesly enough deflegmed and put it into the same Glass first carefully scour'd and cleansed wherein we had put the Oyl olive above-mentioned We took also another Glass differing from a Glass egg onely in that its bottom was flat and fill'd it up to about â…” of the Neck which was wider than that of the Egg with rectified Spirit of Wine We took also another Glass egg and having fill'd it with common Water till it reached to the middle of the Neck we poured to it of the same Spirit of Wine till it reached about an Inch higher These three Glasses having marks set on them over against the edges of the contain'd Liquors were put into the Receiver and that beginning to be evacuated the bubbles in all the three Liquors began to appear The mixture of the Spirit of Wine and Water disclos'd a great store of bubbles especially towards the top but scarce afforded us any thing worth the remembring The Spirit of Urine appear'd to swell near an Inch and an half above the mark and besides that sent forth store of bubbles which made a kind of froth at the upper part of it And above that spume there appear'd eight or ten great bubbles one above another in a very decent order each of them constituting 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 these bubbles reach'd to the top seem'd to be divided into almost equal parts by certain Diaphragmes consisting of the coats of the bubbles whose edges appeared like so many Rings suspended one above another In the Spirit of Wine there did arise a great multitude of bubbles even till weariness did make us give over the Experiment And in these bubbles two or three things were remarkable as first That they ascended with a very notable celerity Next That being arrived at the top they made no stay there and yet notwithstanding the great thinness and spirituousness of the Liquor did before they broke lift up the upper surface of it and for a moment or two form thereof a thin film or skin which appeared protuberant above the rest of the superficies like a small Hemisphere Thirdly That they ascended streight up whereas those produced at the lower part of the Vessel containing the mixture of the Water and Spirit of Wine ascended with a wavering or wrigling motion whereby they described an indented Line Lastly it was observable in the Spirit of Wine and we took notice of the like in the Oyl of Turpentine lately mentioned that not onely the bubbles seemed to rise from certain determinate places at the bottom of the Glass but that in their ascension they kept an almost equal distance from each other and follow'd one another in a certain order whereby they seem'd part of small Bracelets consisting of equally little incontiguous Beads the lower end of each Bracelet being as it were fastned to a certain point at the bottom of the Glass The Air being sparingly let into the Receiver the great bubbles formerly mentioned as incumbent upon one another in that Glass that contained the Spirit of Urine were by orderly degrees lessened till at length they wholly subsided Notwithstanding the recess of so many bubbles as broke on the top of the Spirit of Urine during all the time of the Experiment yet it scarcely appear'd at all to be sunk below the mark Nor did the mixture of Spirit of Wine and Water considerably subside But that is nothing to what we observ'd in the Spirit of Wine for not onely it conspicuously expanded it self in the Neck of the Vessel that contain'd it notwithstanding the largeness of it and that the Bubbles were wont to break at the top of it almost as soon as they arriv'd there But upon the readmission of the external Air the Spirit of Wine retain'd its newly acquired expansion And though we let it alone for near an hour together in expectation that it might subside yet when we took it out we found it still swell'd between a quarter and half an Inch above the mark and although it was not easily imaginable how this Phaenomenon could proceed from any mistake in trying the Experiment yet the strangeness of it invited me to repeat it with fresh Spirit of Wine Which swelling in the Neck as formerly I left all night in the Receiver allowing free access to the external Air at the Stop-cock and the next day found it still expanded as before save that it seem'd a little lower which decrement perhaps proceeded from the avolation of some of the fugitive parts of so voiatile a Liquor And for better satisfaction having taken out the Glass and consider'd it in the open Air and at a Window I could not find that there was any remaining bubbles that could occasion the persevering and admir'd expansion EXPERIMENT XXV BEing desirous to discover what difference there might be as to gravity and levity between Air expanded under Water and it self before such expansion we took two very small Viols such as Chymical Essences as they call them are wont to be kept in and of the size and shape expressed by the eighth Figure into one of these we put so much of a certain ponderous Mercurial mixture hapning to be then at hand that the mouth being stopt with a little soft Wax the Glass would just sink in Water and no more this we let fall to the bottom of a wide-mouth'd Christal Jar fill'd with about half a pint of common Water and into the same Vessel we sunk the other Essence-glass unstop'd with as much water in it as was more than sufficient to make it subside Both these sunk with their mouths downwards the former being about three quarters full of Air the latter containing in it a bubble of Air that was
found that we could not yet so evacuate our Receiver but that the remaining Air though but little in comparison of the exhausted would be able to impell the Water to a greater height than is usual in ordinary Filtrations we resolved instead of a List of Cotton or the like Filtre to make use of a Siphon of Glass delineated in the third Figure consisting of three pieces two streight and the third crooked to joyn them together whose Junctures were diligently clos'd that no Air might find entrance at them One of the Legs of this Siphon was as it should be somewhat longer than the other and was pervious at the bottom of it onely by a hole almost as slender as a hair that the Water might but very leasurely drop out of it lest it should all run out before the Experiment were compleated The other and shorter Leg of the Siphon was quite open at the end and the same wideness with the rest of the Pipe whose bore was about ¼ of an Inch. The whole Siphon made up of these several pieces put together was design'd to be about a Foot and a half long that the remaining Air when the Vessel was exhausted after the wonted manner might not be able to impell the Water to the top of the Siphon which being inverted was fill'd with Water and of which the Shorter leg being let down two or three Inches deep into a Glass Vessel full of Water and the upper parts of it being fasten'd to the inside of the Cover of the Receiver we proceeded to close first and then to empty the Vessel 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 Siphon as if the Experiment had been performed in the free Air. But afterwards the Bubbles as had been apprehended began to disclose themselves in the Water and ascending to the top of the Siphon imbodyed themselves there into one which was augmented by little and little by the rising of other bubbles that from time to time broke into it but much more by its own dilatation which increas'd proportionably to the exsuction that was made of the Air out of the Receiver So that at length the Water in the shorter Leg of the Siphon was reduc'd partly by the extraction of the ambient Air and partly by the expansion of the great Bubble at the upper part of the Siphon to be but about a Foot high if so much whereby it came to pass that the course of the Water in the Siphon was interrupted and that which remain'd in the longer Leg of it continu'd suspended there without dropping any longer But upon the turning of the Stop-cock the outward Air being let into the Receiver got into the Siphon by the little hole at which the Water formerly dropt out and traversing all the incumbent Cylinder of Water in the form of Bubbles joynd it self with that Air that before possess'd the top of the Siphon To prevent the inconveniences arising from these Bubbles two Glass Pipes like the former were so placed as to terminate together in the midst of the Belly of a Glass Viol into whose Neck they were carefully fasten'd with Cement and then both the Viol and the Pipes being which was not done without difficulty totally fill'd with Water the Siphon describ'd in the fifth Figure was plac'd with its shorter Leg in the Glass of Water as formerly and the Experiment being prosecuted after the same manner much more Air than formerly was drawn out before the bubbles disclosing themselves in the water were able to disturb the Experiment because that in the capacity of the Viol there was room enough for them to stretch themselves without depressing the Water below the ends of the Pipes and during this time the Water continued to drop out of the propending Leg of the Siphon But at length the Receiver being very much empty'd the passage of the Water through the Siphon ceas'd the upper ends of the Pipes beginning to appear a little above theremaining Water in the Viol whose dilated Air appear'd likewise to press down the Water in the Pipes and fill the upper part of them And hereby the continuity of the Water and so the Experiment it self being interrupted we were invited to let in the Air again which according to its various proportions of pressure to that of the Air in the Viol and the Pipes did for a good while exhibite a pleasing variety of Phaenomena which we have not now the leasure to recite And though upon the whole matter there seem'd little or no cause to doubt but that if the Bubbles had not disturb'd the Experiment it would manifestly enough have appear'd that the course of Water through Siphons depends upon the pressure of the Air yet we resolv'd at our next leasure and conveniency to try the Experiment again with a quantity of Water before freed from Bubbles by the help of the same Engine This occasion I have had to take notice of Siphons puts me in mind of an odde kind of Siphon that I caus'd to be made ā pretty while ago and which hath been since by an Ingenious Man of Your acquaintance communicated to divers others The occasion was this An eminent Mathematician told me one day that some inquisitive French Men whose Names I know not had observ'd That in case one end of a slender and perforated Pipe of Glass be dip'd in Water the liquor will ascend to some height in the Pipe though held perpendicular to the plain of the Water And to satisfie me that he mis-related not the Experiment he soon after brought two or three small Pipes of Glass which gave me the opportunity of trying it though I had the less reason to distrust it because I remember I had often in the long and slender Pipes of some weather Glasses which I had caus'd to be made after a somewhat peculiar fashion taken notice of the like ascension of the Liquor though presuming it might be casual I had made but little reflexion upon it But after this tryal beginning to suppose that though the Water in these Pipes that were brought me rise not above a quarter of an Inch if near so high yet if the Pipes were made slender enough the Water might rise to a very much greater height I caus'd several of them to be by a dexterous Hand drawn out at the flame of a Lamp in one of which that was almost incredibly slender we found that the Water ascended as it were of it self five Inches by measure to the no small wonder of some famous Mathematicians who were Spectators of some of these Experiments And this height the Water reach'd to though the Pipe were held in as erected a posture as we could For if it were inclin'd the Water would fill a greater part of it though not rise higher in it And we also found that when the inside of the Pipe
70 times its natural extent unless it were that the AEolipile he imploy'd was able to sustain a more vehement heat than ours which yet we kept in so great an one that once the Soder melting it fell asunder into the two Hemispheres it consists of The fore-mentioned way of weighing the Air by the help of an AEolipile seems somewhat more exact than that which Mersennus used In that in ours the AEolipile was not weighed till it was cold whereas in his being weighed red hot it is subject to lose of its substance in the cooling for as we have elsewhere noted on another occasion Copper heated red hot is wont in the cooling to throw off little thin seales in such plenty that having purposely watched a Copper AEolipile during its refrigeration we have seen the place round about it almost covered with those little scales it had every way scatter'd which however they amount not to much ought not to be over-looked when 't is so light a Body as Air that is to be weighed We will not examine whether the AEolipile in cooling may not receive some little increment of weight either from the vapid or saline Steams that wander up and down in the Air But we will rather mention that for the greater exactness we imployed to weigh our AElipile both when fill'd only with Air and when replenish'd with Water a pair of Scales that would turn as they speak with the fourth part of a grain As to the proportion of weight betwixt Air and Water some learned men have attempted it by ways so unaccurate that they seem to have much mistaken it For not to mention the improbable accounts of Kepler and others The learned and diligent Ricciolus having purposely endeavoured to investigate this proportion by means of a thin bladder estimates the weight of the Air to that of the Water to be as one to ten thousand or there abouts And indeed I remember that having formerly on a certain occasion weighed a large bladder full of Air and found it when the Air was all squeesed out to have contained fourteen grains of Air. I found the same bladder afterwards fill'd with Water to contain very near 14 pound of that liquor according to which account the proportion of Air to Water was almost as a grain to a pound that is as one to above 7600. To this we may add that on the other side Galileo himself using another but an unaccurate way too defined the Air to be in weight to Water but as one to 4 hundred But the way formerly proposed of weighing the Air by an AEolipile seems by great odds more exact and as far as we could ghess seemed to agree well enough with the Experiment made in our Receiver Wherefore it will be best to trust our AEolipile in the enquiry we are about And according to our observations the water it contained amounting to one and twenty ounces and an half and as much Air as was requisite to fill it weighing eleven grains the proportion in gravity of Air to Water of the same bulk will be as one to 938. And though we could not fill the AEolipile with water so exactly as we would yet in regard we could not neither as perfectly as we would drive the Air out of it by heat we think the proportion may well enough hold but those that are delighted with round numbers as the phrase is will not be much mistaken if they reckon Water to be near a thousand times heavier than Air. And for farther proof that we have made the proportion betwixt these two Bodies rather greater than lesser than indeed it is and also to confirm our former observation of the weight of the Air we will add That having another time put some Water into the AEolipile before we set it on the fire that the copious vapours of the rarefied liquor might the better drive out the Air we found upon tryal carefully made that when the AEolipile was refrigerated and the included vapours were by the cold turned again into Water which could not have happen'd to the Air that the preceding Steams expelled the Air when it was let in increas'd the weight of the AEolipile as much as before namely Eleven Grains though there were already in it twelve Drachms and a half besides a couple of Grains of Water which remained of that we had formerly put into it to drive out the Air. Mersennus 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 less than of 1300 to 1. And consequently that the quantity of Air to a quantity of Water equiponderant thereto is as 1300 to 1. But why we should relinquish our own carefully repeated tryals I see not Yet I am unwilling to reject those of so accurate and usefull a Writer And therefore shall propose a way of reconciling our differing Observations by presenting that the discrepance between them may probably arise from the differing consistence of the Air at London and at Paris For our Air being more cold and moist than that which Your Lordship now breaths may be suppos'd also to be a fourth or fifth part more heavy I leave it to be consider'd whether it be of any moment that our Observations were made in the midst of Winter whereas his were perhaps made in some warmer time of the Year But I think it were not amiss that by the method formerly propos'd the gravity of the Air were observ'd both in several Countries and in the same Country in the several Seasons of the Year and differing Temperatures of the Weather And I would give something of value to know the weight of such an AEolipile as ours full of Air in the midst of Winter in Nova Zembla if that be true which we formerly â—ook notice of namely That the Hollanders who Wintered there found that Air so thick that their Clock would not go If Your Lordship should now ask me if I could not by the help of these and our other Observations decide the Controversies of our Modern Mathematicians about the height of the Air or Atmosphere by determining how high it doth indeed reach I should answer That though it seems easie enough to shew that divers Famous and Applauded Writers have been mistaken in assigning the height of the Atmosphere Yet it seems very difficult precisely to define of what height it is And because we have hitherto but lightly touch'd upon a matter of such importance we presume it will not be thought impertinent upon this occasion to annex something towards the Elucidation of it What we have already try'd and newly set down allows us to take it for granted that at least about London the proportion of gravity betwixt Water and Air of equal bulk is as of a thousand to one The next thing therefore that we are to enquire after in
small Glass not containing above a pound and a half of Water the Phaenomenon might be exhibited though the Stop-cock were open provided the Sucker were drawn nimbly down We noted too that when we began to empty the Receiver the appearances of Light were much more conspicuous than towards the latter end when little Air at a time could pass out of the Receiver We observed also that when the Sucker had not been long before well Oyl'd and instead of the great Receiver the smaller Vessel above-mention'd was emptied We observ'd I say that then upon the opening of the Stop-cock as the Air descended out of the Glass into the emptied Cylinder so at the same time there ascended out of the Cylinder into the Vessel a certain steam which seem'd to consist of very little Bubbles or other minute Corpuscles thrown up from the Oyl rarefied by the attrition it suffered in the Cylinder For at the same time that these Steams ascended into the Glass some of the same kind manifestly issued out like a little Pillar of Smoke at the Orifice of the Valve when that was occasionally opened And these Steams frequently enough presenting themselves to our view we found by exposing the Glass to a clear Light that they were wont to play up and down in it and so by their whitishness to emulate in some measure the apparition of Light For we likewise sometimes found by watchfull observation that when the Flash was great not only at the very instant the Receiver lost of its transparency by appearing full of some kind of whitish substance but that for some short time after the sides of the Glass continued somewhat opacous and seem'd to be darken'd as if some whitish Steam adher'd to the inside of them He that would render a Reason of the Phaenomenon whereof all these are not all the Circumstances must do two things whereof the one is difficult and the other little less than impossible For he must give an account not only whence the appearing whiteness proceeds but wherefore that whiteness doth sometimes appear and sometimes not For our part we freely confess our selves at a loss about rendering a Reason of the less difficult part of the Problem And though Your Lordship should ev'n press us to declare what Conjecture it was that the above recited Circumstances suggested to us we should propose the thoughts we then had no otherwise than as bare Conjectures In case then our Phaenomenon had constantly and uniformly appear'd we should have suspected it to have been produc'd after some such manner as follows First we observ'd that thought that which we saw in our Receiver seem'd to be some kind of Light yet it was indeed but a whiteness which did as hath already been noted opacate as some speak the inside of the Glass Next we consider'd that our common Air abounds with Particles or little Bodies capable to reflect the beams of Light Of this we might easily give divers proofs but we shall name but two The one that vulgar observation of the Motes that appear in multitudes swimming up and down in the Air when the Sun-beams shooting into a Room or any other shady place discover them though otherwise the Eye cannot distinguish them from the rest of the Air The other proof we will take from what we and no doubt very many others have observ'd touching the Illumination of the Air in the Night And we particularly remember that being at some distance from London one Night that the People upon a very welcome occasion testified their Joy by numerous Bon-fires though by reason of the Interposition of the Houses we could not see the Fires themselves yet we could plainly see the Air all enlighten'd over and near the City which argu'd that the lucid Beams shot upwards from the fires met in the Air with Corpuscles opacous enough to reflect them to our Eyes A third thing that we considered was That white may be produc'd without excluding otherways or denying invisible Pores in the solidest Bodies when the continuity of a Diaphanous Body happens to be interrupted by a great number of surfaces which like so many little Looking-glasses do confusedly represent a multitude of little and seemingly contiguous Images of the lucid Body We shall not insist on the explanation of this but refer You for it to what we have said in another Paper touching Colours But the Instances that seem to prove it are obvious For Water or whites of Eggs beaten to froth do lose their transparency and appear white And having out of one of our lessers Receivers carefully drawn out the Air and so order'd it that the hole by which the Water was to get in was exceeding small that the Liquor might be the more broken in its passage thorow it we observ'd with pleasure That the Neck being held under Water and the little hole newly mention'd being open'd the Water that rushed in was so broken and acquired such a multitude of new Surfaces that the Receiver seem'd to be full rather of Milk than Water We have likewise found out That by heating a lump of Crystal to a certain degree and quenching it in fair Water it would be discontinu'd by such a multitude of Cracks which created new Surfaces within it that though it would not fall asunder but retain its former shape yet it would lose its transparency and appear white Upon these Considerations My Lord and some others it seem'd not absur'd to imagine That upon the rushing of the Air out of the Receiver into the empty'd Cylinder the Air in the Receiver being suddenly and vehemently expanded the Texture of it was as suddenly alter'd and the parts made so to shift places and perhaps some of them to change postures as during their new and vehement motion and their varied situation to disturb the wonted continuity and so the Diaphaneity of the Air which as we have already noted upon its ceasing to be a transparent Body without the interposition of colour'd things must easily degenerate into white Several things there were that made this Conjecture seem the less improbable As first That the whiteness always appear'd greater when the exsuction began to be made whilst there was store of Air in the Receiver than when the Air was in great part drawn out And next That having exhausted the Receiver and apply'd to the hole in the Stop-cock a large bubble of clear Glass in such a manner that we could at pleasure let the Air pass out at the small Glass into the great one and easily fill the small one with Air again We observ'd with pleasure That upon the opening the passage betwixt the two Glasses the Air in the smaller having so much room in the greater to receive it the Dissilition of that Air was so great that the small Viol seem'd to be full of Milk and this Experiment we repeated several times To which we may add That having provided a small Receiver whose upper Orifice was so narrow that
sinding there did only arise as formerly a pretty number of small Bubbles that made there no sensible froth upon the surface of the distill'd Vineger there were made two or three exsuctions of the Air upon which there emerg'd from the Coral such a multitude of Bubbles as made the whole Body of the Menstruum appear white and soon aster a Froth as big as all the rest of the Liquor was seen to swim upon it And the Menstruum plainly appear'd to boil in the Glass like a seething Pot. And though if we desisted but one minute from pumping the decrement of the Froth and Ebullition upon the getting in of a little Air at some leak or other seem'd to argue that the removal of the pressure of the external Air was the cause or at least the occasion of this Effervescence Yet to evince this the more clearly we turn'd the Key and let in the external Air at the Stop-cock immediately upon whose entrance the Froth vanish'd and so many of the Bubbles within the body of the Liquor disappear'd that it lost its whiteness and grew transparent again The Menstruum also working as languidly upon the Coral as it did before they were put into the Receiver But when we had again drawn out the Air first the whiteness re-appear'd then the Ebullition was renew'd which the pumping being a while longer and nimbly pursued grew so great that for 3 or 4 times one aster another when ever the Air was let out of the Receiver into the emptied Cylinder the frothy liquor overflow'd the Glass and ran down by the sides of it And yet upon the readmitting of the excluded Air the boiling Liquor grew immediately as calm and as transparent as at first As if indeed the operation of it upon the Coral had been facilitated by the exsuction of the incumbent Air which on its recess lest it more easie sor the more active parts of the liquor to shew themselves such than it was whilst the wonted pressure of the Air continued unremoved It may indeed be suspected that those vast and numerous Bubbles proceeded not from the action of the Menstruum upon the Coral but from the suddain emersion of those many little parcels of Air that as we formerly observ'd are wont to be dispers'd in Liquors without excluding Spirit of Vineger but having had this suspicion before we try'd the Experiment we convey'd our distill'd Vineger alone into the Receiver and kept it a while there to free it from its Bubbles which were but very small before ever we put the Coral into it It may be suspected likewise that the agitation of the Liquor necessary following upon the shaking of the Glass by pumping might occasion the recited Ebullition but upon trial made there appear'd not any notable change in the Liquor or its operation though the containing Vessel were shaken provided no Air were suck'd out of it The former Experiment was another time try'd in another small Receiver with Coral grosly powdred and the success was very much alike scarce differing in any thing but that the Coral being reduc'd to smaller parts upon the ebullition of the Liquor so many little lumps of Coral would be carried and Boy'd up by the emerging Bubbles as sometimes to darken the Viol though the same Coraline Corpuscles would be let fall again upon the letting in of the Air. Some thing also we try'd in our great Receiver concerning the solution of Metals in Aqua fortis and other Corrosive Liquors but partly the stink and partly some accidents kept us from observing any thing peculiar and remarkable about those Solutions One thing we must not omit that when the Spirit of Vineger was boiling upon the Coral we took off the Cover of the Receiver and took out the Viol but could not find that notwithstanding so very late an Ebullition the Liquor had any heat great enough to be at all sensible to our hands EXPERIMENT XLIII WE will now subjoyn an Experiment which if the former did not lessen the wonder of it would probably appear very strange to Your Lordship as it did to the first Spectators of it The Experiment was this We caus'd Water to be boil'd a pretty while that by the heat it might be freed from the latitant Air so often already taken notice of in common Water Then almost filling with it a Glass Viol capable of containing near four Ounces of that Liquor we convey'd it whilst the Water was yet hot into one of our small Receivers big enough to hold about a pound of Water and having luted on the Cover we caus'd the Air to be drawn out Upon the two first exsuctions there scarce appear'd any change in the Liquor nor was there any notable alteration made by the third but at the fourth and afterwards the Water appear'd to boil in the Viol as if it had stood over a very quick Fire for the Bubbles were much greater than are usually found upon the Ebullition of very much more Water than was contain'd in our Viol. And this Effervescence was so great in the upper part of the Water that the Liquor boyling over the top of the Neck a pretty deal of it ran down into the Receiver and sometimes continued though more languidly boyling there Prosecuting this Experiment we observ'd that sometimes after the first Ebullition we were reduc'd to make divers exsuctions of the Air before the Liquor would be brought to boil again But at other times as often as the Key was turn'd to let the Air pass from the Receiver into the Pump the Effervescence would begin afresh though the Pump were ply'd for a pretty while together which seem'd to argue that the boyling of the Water proceeded from hence That upon the withdrawing the pressure of the incumbent Air either the fiery Corpuscles or rather the Vapors agitated by the heat in the Water which last what we have formerly noted touching the raresied Water of an AEolipile manifest to be capable of an Elastical Power were permitted to expand themselves mightily in the evacuated Receiver and did in their tumultuous Dilatation list up as the Air is wont to do the uppermost part of the Water and turning it into Bubbles made the Water appear boiling This conjecture was farther confirm'd by these additional Circumstances First The Effervescence was confin'd to the upper part of the Water the lower remaining quiet unless the Liquor were but shallow Next although sometimes as is already noted the Ebullition began again after it had ceas'd a pretty while which seem'd to infer That some concurrent cause whatever that were did a little modifie the operation of heat yet when the Water in the Viol could by no pumping be brought to boil any more the self-same Water being in the very same Viol warm'd again and reconvey'd into the Pneumatical Glass was quickly brought to boil afresh and that vehemently and long enough not to mention that a new parcel taken out of the same parcel of the boiled
and Time on Matter than Words and so are justly impeded from learning Languages And because as I may judge the Noble Author is willing to oblige all Men He hath already provided that this Piece shall shortly be done into Latine that so it may come home to divers worthy Persons in its Stream who cannot travel to find it out in its first Origine Having therefore leave so to do I cannot forbear to give the World the Advertisement of this Latine Edition lest some skilfull Artist should take needless pains about a work which will ere long by God's furtherance be done to his Hands For such unprofitable expences of Study have too frequently hapened and too much to the disadvantage of Learning for want of a sufficient Correspondence and intercourse between such as are exercised in the Mines of Wisedom This is all the trouble I shall at present give you Nor shall I need mind you if you have a true gust for the Book you reade to have an honour and thankfull regard to the Person that hath favour'd us with the Communication of these his Trials and is manifestly so great a Patron and Friend to Experimental Learning and all true Wisedom for should you fail in this you might deservedly be depriv'd of some other Observations on the same subject which the Author I hear hath made since the finishing of this Treatise I desire to be excused that I do not make Excuses for the slowness of the Publication hoping that the long expectation you have had of it will enhance and not diminish your delight in the enjoyment of a piece like to be amongst the Students in accurate Philosophy of so general acceptance Farewell R. Sh. A SUMMARY of the chief Matters treated of in this Epistolical Discourse THe Proaemium wherein is set down the occasion of this discourse 1. The motives that induc'd the Author thereunto 2. The hints he received 3. The things wherein this Engine excels any that have yet been made use of 4. The description of the Engine and its parts 5 c. The way of preparing and using it 8 c. The division of the Experiments triable thereby into two sorts and the difficulty of excluding the Air. 10 c. The first Experiment touching the manner of pumping out the Air and by what degrees the Receiver is emptied 11 c. A digression touching the Spring or Elastical power of the Air with an attempt for a Mechanical Explication thereof necessary to be premis'd for the explanation of the Phaenomena exhibited in this and the subsequent Experiments 12 c. The second Experiment touching the pressure of the Air against the sides of the Bodies it invirons 20 c. with a digressive Explication of the pressure of the Air included within an ambient Body 21 c. The third Experiment touching the force requisite to draw down the Sucker 23 c. The Opinion of an eminent Modern Naturalist examin'd 24 c. The fourth Experiment touching the swelling of a Bladder with the degrees by which it increaseth 25 c. Another Opinion of a Learned Author examin'd 26 c. The fifth Experiment touching the breaking of a Bladder in the Receiver And of another by heat 27 28. The sixth Experiment of divers ways by which the elastical expansion of the Air was measur'd 29 c. The seventh Experiment touching what Figure doth best resist the pressure of the Air. 33 The eight Experiment tending to a farther Demonstration of the former from the breaking of a glass Helmet inward 34 The ninth Experiment contains a farther confirmation from the breaking of a Glass outward 35 c. with an Experiment to prove that these Phaenomena proceed not from an invincible Fuga vacui 37. A description of other small Receivers and their conveniencies 38 c. A Receipt for the making of a Composition to cement crack'd Glasses 39 The tenth Experiment touching the flaming of Candles inclosed in the Receiver 39 c. The eleventh Experiment touching the burning of Coals and the lasting of the excandescence of an included piece of Iron 42 The twelfth Experiment concerning the burning of Match 44 The thirteenth Experiment concerning the farther prosecution of the preceding tending to prove the extinction of the Fire in the former Experiments not to have proceeded from the pressure of the Fire by the Fumes Some remarkable Circumstances of it The Experiment of Match try'd in a Small Receiver 45 c. The fourteenth Experiment touching the striking Fire and klindling of Powder with the Lock of a Pistol in the evacuated Receiver 47 c. The fifteenth Experiment touching the unsuccessfulness of kindling included Bodies with a Burning-glass and the Author's intention to prosecute it farther 49 The sixteenth Experiment concerning the operation of the Loadstone 52 The seventeenth Experiment touching the gradual descent of the Quick-silver in the Torricellian Experiment 51 c. Some observable Circumstances concerning it 54 c. The same Experiment try'd in one of the small Receivers 55. How this Experiment may be made use of to know the strength of the pressure of the Air for every degree of Rarefaction 56 c. The trial of the same Experiment in a Tube not two foot long 57. The raising of the Mercurial Cylinder by the forcing of more Air into the Receiver ib. Some Allegation for and against a Vacuum considered 59 c. Some Advertisements concerning the inconveniencies that may arise from the diversity of measures made use of for the defining the altitude of the Mercurial Cylinder and from the neglect of little parcels of Air apt to remain between the Mercury and the concave surface of the Tube 60 c. Some Expedients for the more exact filling the Tube 61. The height the Author once found of the Mercurial Cylinder according to English measure 63 The eighteenth Experiment containing a new Observation touching the variation of the height of the Mercurial Cylinder in the same Tube with an offer at the Reason thereof 63 c. The nineteenth Experiment touching the subsiding of a Cylinder of Water 69. The same try'd in a small Receiver 70 The twentieth Experiment touching the Elater of Water with a digressive Experiment to the same purpose 71 c. The 21 Experiment being a prosecution of the former Enquiry by experimenting the Generation of Bubbles under Water a recital of some not able Circumstances with some observable Corollaries deduc'd therefrom 73 c. The 22 Experiment tending to a determination of the Enquiry propos'd in the former Experiment by proving the matter of these Bubbles from their permanency to be Air The Experiments try'd in the great and small Receivers evincing the same thing 77 c. An Experiment wherein there appear'd Bubbles in Quick-silver 79. The Author's Inference 80. A digressive Enquiry whether or no Air may be generated anew with several Histories and Experiments tending to the resolving and clearing thereof ibid. c. The Author's excuse for so long
Experiment This will perhaps make it seem strange that having taken another Glass bubble blown at the same time and like for ought we discerned for size thickness and Figure to that thin one formerly mentioned and having sealed it up Hermetically and suspended it in the Receiver the exsuction of the ambient Air did not enable the imprisoned Air to break or in the least to crack the bubble though the Experiment were laboriously tried and that several times with bubbles of other sizes But that perhaps the heat of the Candle or Lamp wherewith such Glasses are Hermetically sealed not to mention the warmth of his hands that seal'd it might so rarefy the contained Air as much to weaken its Spring may seem probably by the following Experiments EXPERIMENT IX WE took a Glass Viol able to hold three or four Ounces of Water and of the thickness usual in Glasses of that size into the Neck of this was put a moderately slender Pipe of Glass which was carefully fastened with a mixture of equal parts of Pitch and Rosin to the Neck of the Viol and which reached almost to the bottom of it as the sixth Figure declareth This Viol being upon a particular design filled with Water till that came up in it a pretty deal higher than the lower end of the Pipe was put into one of our small Receivers containing between a Pint and a Quart in such manner as that the Glass Pipe passing through a hole made purposely for it in the Leaden-Cover of the Receiver was for the most part of it without the Vessel which being exactly closed the Pump was set on work But at the very first exsuction and before the Sucker was drawn to the bottom of the Cylinder there flew out of the Viol a piece of Glass half as broad as the Palm of a Man's Hand and it was thrown out with such violence that hitting against the Neighbouring side of the Receiver it not onely dashed it self to pieces but cracked the very Receiver in many places with a great noise that much surprised all that were in the Room but it seemed that in so little a Receiver the Air about the Viol being suddenly drawn out the Air imprisoned in the Vessel having on it the whole pressure of the Atmosphere to which by the Pipe open at both ends It and the Water were exposed and not having on the other side the wonted pressure of the Ambient Air to ballance that other pressure the resistance of Glass was finally surmounted and the Viol once beginning to break where it was weakest the external Air might rush in with violence enough to throw the cracked parcel so forcibly against the Neighbouring side of the Receiver as to break that too And this may be presumed sufficient to verify what we delivered in that part of our Appendix to the first Experiment where we mentioned the almost equal pressure of the Air on either side of a thin Glass Vessel as the cause of its not being broken by the forcible spring of the contained Air. But yet that it be not suspected that chance had an interest in so odd an Experiment as we have been relating we will add that for farther satisfaction we reiterated it in a round Glass containing by Guess about six ounces of Water This Viol we put into such a small Receiver as was lately mentioned in such manner as that the bottom of it rested upon the lower part of the Pneumatical Glass and the Neck came out through the Leaden-cover of the same at a hole made purposely for it But being made circumspect by the foregoing mischance we had put the Viol into a Bladder before we put it into the Receiver to hinder this last-named Glass from being endangered by the breaking of the other Then the Pneumatical Vessel being closed so that no way was left for the outward Air to get into it but by breaking through the Viol into whose cavity it had free access by the mouth of it which was purposely left open the Sucker being nimbly drawn down the external Air immediately pressed forcibly as well upon the Leaden-cover as the Viol and the Cover happening to be in one place a little narrower than the edge of the Pneumatical Glass was depressed and thrust into it so violently by the incumbent Air that getting a little within the tapering Lip of the Glass it did like a kind of Wedge thrust out that side where it was depressed so as though the Receiver was new to split it This accident being thus mentioned upon the bye to confirm what we formerly said touching the fitness or unfitness of Glasses of some Figures to resist the pressure of the Atmosphere We will proceed to relate the remaining part of the Experiment namely That having fitted on a wider Cover to the same Receiver and closed both that and the crack with Cement we prosecuted the Experiment in the manner above related with this success That upon the quick depressing of the Sucker the external Air burst the Body of the Viol into above an hundred pieces many of them exceeding small and that with such violence that we found a wide rent besides many holes made in the Bladder it self And to evince that these Phaenomena were the effects of a limited and even moderate force and not of such an abhorrency of a Vacuum as that to avoid it many have been pleased to think that Nature must upon occasion exercise an almost boundless power we afterwards purposely try'd this Experiment with several Glasses somewhat thicker than those Viols and found the event to verify our conjecture that it would not succeed For the Glasses were taken out as intire as they were put in And here My Lord I hold it not unfit upon occasion of the mention that hath been made of our having employ'd small Receivers and one of them notwithstanding its being crack'd to annex these two Advertisements First then besides the great Pneumatical Glass so often mentioned and the proportionate Stop-cock we thought fit to provide our selves with some small Receivers blown of Crystalline Glass of several Shapes and furnished with smaller Stop-cocks purposely made and this we did upon hopes that when we had surmounted the difficulties to be met with in Cementing the Glasses to the Stop-cocks and the Pneumatical Vessels to the Pump so exquisitely as is requisite for our purpose we should from the smallness of our Receivers receive a four-fold Advantage The first that by reason of the slenderness of the Vessels and their being made of much purer and clearer metal as the Glass-men speak than the great Receiver we might have a more perfect view of every thing happening within them The next that such small Vessels might be emptied with less labour and in much less time The third that this nimble exsuction of the ambient Air would make many changes in the Bodies shut up in these Glasses more sudden and conspicuous than otherwise they would prove And the last that
suspicion the Experiment about the Coals might easily suggest and which the event declar'd not to have been altogether groundless For upon the admission of the external Air the Fire that seem'd to have gone out a pretty while before did presently revive and being as it were refresh'd by the new Air and blown by the Wind made by that Air in rushing in it began again to shine and dissipate the neighbouring Fuel into Smoke as formally EXPERIMENT XIII A While after we let down into the Receiver together with a lighted piece of Match a great Bladder well tyed at the Neck but very lank as not containing actually much if any thing above a Pint of Air but being capable of containing ten or twelve times as much Our scope in this Experiment was partly to try whether or no the smoke of the Match replenishing the Receiver would be able to hinder the dilatation of the inward Air upon the exsuction of the ambient And partly to discover whether the extinction of the Fire in the Match did proceed from want of Air or barely from the pressure of its own Fumes which for want of room to expand themselves in might be suppos'd to recoyl upon the Fire and so to stifle it The event of our tryal was That at the beginning of our pumping the Match appear'd well lighted though it had almost fill'd the Receiver with its plentifull Fumes But by degrees it burnt more and more dimly notwithstanding that by the nimble drawing out the Air and Smoke the Vessel were made less opacous and less full of compressing matter as appear'd by this That the longer we pump'd the less Air and Smoke came out of the Cylinder at the opening of the Valve and consequently the less came into it before yet the Fire in the Match went but slowly out And when afterwards to satisfy our selves of its expiration we had darken'd the Room and in vain endeavoured to discover any spark of Fire as we could not for some time before by the help of Candles discern the least rising of Smoke we yet continued pumping six or seven times and after all that letting in the Air the seemingly dead Fire quickly revived and manifested its recovery by Light and store of Smoke with the latter of which it quickly began to replenish the Receiver Then we fell to pumping afresh and continued that labour so long till the re kindled Match went out again and thinking it then fit not to cease from pumping so soon as before we found that in less than half a quarter of an hour the Fire was got out for good and all and past the possibility of being recover'd by the re-admitted Air. Some Circumstances besides those already mention'd occurr'd in the making of the Experiment of which these are the principal First When the Receiver was full of Smoke if the Cylinder were emptied immediately upon the turning of the Stop-cock the Receiver would appear manifestly darken'd to his eye that look'd upon the light through it and this darkness was much less when the Receiver was much less fill'd with Fumes It was also instantaneous and seem'd to proceed from a sudden change of place and situation in the exhalations upon the vent suddenly afforded them and the Air they were mixt with out of the Receiver into the Cylinder The next thing we observed was a kind of Halo that appear'd a good while about the Fire and seem'd to be produced by the surrounding Exhalations And lastly it is remarkable That even when the Fumes seemed most to replenish the Receiver they did not sensibly hinder the Air included in the Bladder from dilating it self after the same manner for ought we could discern as it would have otherwise done So that before the Fire or the Match was quite extinct the Bladder appear'd swell'd at least to six or seven times its former capacity Since the writing of these last Lines we took a small Receiver capable of containing by guess about a pound and a half of Water and in the midst of it we suspended 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 such haste but that before we began to pump the Smoke had so fill'd that small Receiver as for ought we discern'd to choke the Fire And having again and again reiterated the Experiment it seem'd still as at first that we could not close up the Vessel and pump out all the Fumes time enough to rescue the Fire from extinction whereupon we made use of this Expedient Assoon as we had pump'd once or twice we suddenly turn'd the Key and thereby gave access to the excluded Air which rushing violently in as if it had been forced thorow a pair of Bellows did both drive away the ashes fill the Glass with fresh Air and by blowing the almost extinguish'd Fire re-kindl'd it as appear'd by the Matches beginning again to smoke which before it had ceas'd to do we having by this means obtained a lighted Match in the Receiver without being reduced to spend time to close it up commanded the Air to be immediately pump'd out and found that upon the exsuction of it the Match quickly left smoking as it seem'd by reason of the absence of the Air and yet if some urgent occasions had not hinder'd us we would for greater security have try'd whether or no the Match rekindled as formerly would smoke much longer in case of no exsuction of the ambient Air. EXPERIMENT XIV TO try diverse things at once and particularly whether Fire though we found it would not long last might not be produced in our evacuated Receiver We took a Pistol of about a foot in length and having firmly tyed it to a stick almost as long as the Cavity of the Receiver we very carefully prim'd it with well dry'd Gunpowder and then cocking it we ty'd to the Tricker one end of a string whose other end was fasten'd to the Key formerly mention'd to belong to the Cover of our Receiver This done we convey'd the Pistol together with the annexed Staff into the Vessel which being clos'd up and empty'd aster the usual manner we began to turn the Key in the Cover and thereby shortning the string that reach'd from it to the Pistol we pull'd aside the Tricker and observ'd that according to our expectation the force of the Spring of the Lock was not sensibly abated by the absence of the Air from whose impetus yet some Modern Naturalists would derive the cause of the motion of Restitution in solid Bodies For the Cock falling with its wonted violence upon the Steel struck out of it as many and as conspicuous parts of Fire as for ought we could perceive it would have done in the open Air. Repeating this Experiment diverse times we also observed whether or no there would appear any considerable diversity in the Motion of the shining Sparks in
in the Receiver should be drawn out to bring the remaining Air to an AEquilibrium with so short and light a Cylinder of Water But when once the Water began to fall in the Tube then each exsuction of Air made it descend a little lower though nothing near so much as the Quick-silver at the beginning did in the Experiment formerly mention'd Nor did there appear so much inequality in the spaces transmitted by the Water in its descent as there it did in those observ'd in the fall of the Quick-silver of which the cause will scarce seem abstruse to him that shall duly reflect upon what hath been already deliver'd And whereas we drew down the Quick-silver in the Tube so far as to bring it within an Inch of the surface of the other Quick-silver into which it was to fall the lowest we were able to draw down the Water was by our conjecture to about a Foot or more above the surface of that in the Vessel of which I know not whether it will be needfull to assign so obvious a cause as that though the little Air remaining in the Receiver could not hinder a Cylinder of above on Inch high of Quick-silver from subsiding yet it might be very well able by its pressure to countervail the weight of a Cylinder of a Foot long or more of a Liquor so much less ponderous than Quick-silver 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 again to the higher parts of the Tube We will adde no more concerning this Experiment save that having try'd it in one of our small Receivers we observ'd That upon the first exsuction of the Air the Water did usually subside divers Inches and at the second exsuction fall down much lower subsiding sometimes near two Foot as also that upon the letting in of the Air from without the Water was impell'd up with very great celerity EXPERIMENT XX. THat the Air hath a notable Elastical power whencesoever that proceeds we have I suppose abundantly evinc'd and it Begins to be acknowledg'd by the eminentest Modern Naturalists But whether or no there be in Water so much as a languid one seems hitherto to have been scarce consider'd nor hath been yet for ought I know determin'd either way by any Writer which invited us to make the following Experiment There was taken a great Glass bubble with a long neck such as Chymists are wont to call a Philosophical Egge which being fill'd with common Water till the Liquor reach'd about a span above the bubble and a piece of Paper being there pasted on was put unstop'd into the Receiver and then the Air was suck'd out after the wonted manner The event was this that a considerable part of the Air pen'd up in the Receiver was drawn out before we discern'd any expansion of the Water but continuing the labour of pumping the Water manifestly began to ascend in the stem of the Glass and divers bubbles loosening themselves from the lower parts of the Vessel 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 appear'd to swell 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 Glass did suddenly rise about the breadth of a Barly-corn in the Neck of the Glass and so attain'd by degrees to a considerable height above the mark formerly mention'd And at length to make the expansion of the Water more evident the outward Air was suddenly let in and the Water immediately subsided and deserted all the space it had newly gain'd in the Glass And on this occasion it will not perhaps be amiss to acquaint Your Lordship here though we have already mention'd it in another Paper to another purpose with another Expedient that we made use 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 Philosophy Dr. Wilkins doing me the Honour to come himself and bring some of his inquisitive Friends to my Lodging we there had in readiness a round and hollow Vessel of Pewter great enough to contain two pounds of Water and exactly close every where but at one little hole where it was to be fill'd then partly by sucking out the Air and partly by injecting Water with a Syringe it was not without some difficulty fill'd up to the top and that hole being plac'd directly upwards there was a little more Water leisurely forc'd in by the Syringe Upon which though the Vessel were permitted to rest and the hole kept in its former posture yet the compress'd Water leisurely swell'd above the Orifice of the hole and divers drops ran over along the sides of the Vessel After this we caus'd a skilfull Pewterer who had made the Globe to close it up in our presence with Soder so exquisitely that none suspected there was any thing left in it besides Water And lastly the Vessel thus soder'd up was warily and often struck in divers places with a Wooden Mallet and thereby was manifestly compress'd whereby the inclosed Water was crouded into less room than it had before And thereupon we took a Needle and with it and the Mallet perforated the Vessel and drew out the Needle again the Water but in a very slender Stream was suddenly thrown after it into the Air to the height of two or three Feet As for the other Phaenomena of this Experiment since they belong not to our present purpose and are partly mention'd in another of our Papers we shall instead of recording them here give this Advertisement That as evidently as this Experiment and that made in our Receiver seem to prove a power in the Water to expand and restore it self after compression yet for a reason to be met with ere long I judged it not safe to infer that Conclusion from these Premises till I had made some of the following tryals to the mention of which I will therefore hasten EXPERIMENT XXI TO discover whether the Expansion of the Water really proceeded from an Elastical power in the parts of the Water it self we thought it requisite to try two things The one Whether or no the Atmosphere gravitates upon Bodies under Water and the other Whether in case it do gravitate the Intumescence of the Water may not be ascribed to some substance subtler than it self residing in it In order to the satisfying myself about the first of these I intended to let down into the Receiver a Vessel of Water wherein should be immers'd a very small oyl'd Bladder almost devoid of Air but strongly ty'd up at the Neck with a string and detain'd a little under Water by such a weight fasten'd to that string as should just be able to keep
That having by letting in the Air forc'd up the Water into the Tube we could not perceive that it ascended near the top though we permitted the Engine to remain unimploy'd for two or three Nights together and watch'd whether the Water would swell up and fill the Tube And on this occasion I remember that having try'd such an Experiment as this with Quick-silver instead of Water in a Tube of about a Foot and a half long wherein it might seem more hopefull to escape bubbles yet upon the drawing down the Quick-silver as low as we could and letting in the external Air upon it we found that some lurking particles of Air were got up to the top of the Tube and hinder'd the Quick-silver from being forc'd up again so high And though the Quick-silver were by this means brought to appear a very close and lovely Metalline Cylinder not interrupted by interspers'd bubbles as before yet having caus'd the Air to be again drawn out of the Receiver I could perceive several little bubbles to disclose themselves fasten'd to the inside of the Tube near the bottom of it and having purposely watch'd one or two of the chiefest I had the pleasure to observe that though they grew bigger and bigger as the surface of the Mercurial Cylinder fell nearer and nearer to them so as that at length they swell'd into a conspicuous bulk yet upon the wary letting in the Air upon them they did not break but presently shrunk up into a littleness that render'd them inconspicuous Whence it seems very probable if not certain that even in the closest and most ponderous Liquors and therefore much more in Water there may lurk undiscernable parcels of Air capable upon the removal of the pressure of the ambient Air though but in part and that of the liquor wherein it lurks to produce conspicuous bubbles And consequently if it seem inconvenient to admit an Elastical power in the Water it may be said that the swelling of the compress'd Water in the Pewter Vessel lately mention'd and the springing up of the Water at the hole made by the Needle were not the effects of any internal Elater of the Water but of the spring of the many little particles of Air dispers'd through that Water and acting upon it in their sudden recovering themselves to a greater extent than that to which a violent compression had reduc'd them to But though from all these particulars it seems manifest that the Bubbles we have been all this while treating of were produc'd by such a substance as may be properly enough call'd Air yet till we shall have had the opportunity of making some farther tryals concerning the nature of the Air we shall not resolutely determine whether or no Air be a Primogenial Body if I may so speak that cannot now be generated or turn'd either into Water or any other Body Yet in the mean while because it is an important Question and if rightly determin'd may much conduce to the knowledge of the nature of the Air we think it not unfit to make a brief mention of some of the particulars which at present occur to our thoughts in favor of either part of the Question First then divers Naturalists esteem the Air as well as other Elements to be ingenerable and incorruptible And reasons plausible enough may be drawn to countenance this Opinion from the consideration of that permanency that ought to belong to the corporeal Principles of other Bodies Next Experience may be pleaded to the same purpose for I have read of some who in vain attempted to turn Air into Water or Water into Air. The diligent Schottus tells us that amongst other rarities to be met with in that great Repository of them the Musaeum Kercherianum there is a round Glass with a tapering neck near half full as one may guess by the Scheme he annexeth of ordinary spring-Spring-water which having been hermetically shut up there by Clavius the famous Geometrician the included Water is to this day preserv'd not onely clear and pure as if it were but newly put in But as it seems without in the least turning into Air notwithstanding its having been kept there these fifty years For he tells us That the Water hath continued there all this while without any diminution Nor doth it appear in those Glasses which for Chymical Experiments we usually close with Hermes his Seal as they call it that the included Air doth during its long imprisonment notwithstanding the alteration it receiveth from various degrees of heat discernably alter its nature Whereas we plainly perceive in our Digestions and Distillations that though Water may be rarefied into invisible Vapors yet it is not really chang'd into Air but onely divided by heat and scatter'd into very minute parts which meeting together in the Alembick or in the Receiver do presently return into such Water as they constituted before And we also see that even Spirit of Wine and other subtle and fugitive Spirits though they easily fly into the Air and mingle with it do yet in the Glasses of Chymists easily lay aside the disguise of Air and resume the divested form of Liquors And so volatile Salts as of Urine Harts-horn c. though they will readily disperse themselves through the Air and play up and down in the capacity of an Alembick or a Receiver yet will they after a while fasten themselves to the insides of such Glasses in the form of Salts Besides since Air is confessedly endow'd with an Elastical power that probably proceeds from its Texture it appears not what it is that in such light alterations of Water as are by many presum'd capable of turning it into Air can be reasonably suppos'd so to contrive the Particles of Water as to give them and that permanently the structure requisite to a Spring I add the word permanently because the newly mention'd observations seem to argue the Corpuscles of Air to be irreducible into Water whereas the Aqueous Particles may perhaps for a while be so vehemently agitated as to press almost like Springs upon other Bodies yet upon the ceasing of the agitation they quickly by relapsing into Water disclcse themselves to have been nothing else whilst they counterfeited the Air. Lastly The Experiment formerly made in our Engine with a piece of Match seems to evince that even those light and subtle Fumes for the most part not aqueous neither into which the Fire it self shatters dry Bodies have no such Spring in them as the Air since they were unable to hinder or repress the expansion of the Air included in the Bladder they surrounded I remember indeed that the Learned Josephus Acosta in his History of the West Indies tells us That he saw in those parts some Grates of Iron so rusted and consum'd by the Air that the Metal being press'd between the Fingers dissolv'd to use his words to powder as if it had been Hay or parched Straw And I remember too that the Accurate
guess'd to be of the bigness of half a Pea This done the wide mouth'd Glass was let down into the Receiver and the way of employing the Engine was carefully made use of The success was That having drawn out a pretty quantity of Air the bubbles began to disclose themselves in the Water as in the former Experiments and though for a good while after the bubbles ascended in swarms from the lower parts of the Water and hastily broke at the top yet we prosecuted the Experiment so long without seeing any effect wrought upon the Essence-bottles that we began to despair of seeing of them rise But continuing to ply the Pump that little Glass whose 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 fastned themselves to the sides of it swimming thus with the mouth downward we could easily perceive that the internal Air above-mention'd had much dilated it self and thereby seem'd to have contributed to the emerging of the Glass which remain'd floating notwithstanding the breaking and vanishing of most of the contiguous bubbles being hereby incouraged to persist in pumping we observed with some pleasure that at each time we turn'd the Key the Air in the little Glass did manifestly expand it self and thrust out the Water generally retaining a very protuberant surface where it was contiguous to the remaining Water And when after divers exsuctions of the Air in the Receiver that in the Viol so dilated it self as to expel almost all the Water it turn'd up its mouth towards the surface of the Water in the Jar and there deliver'd a large bubble and then relapsed into its former floating posture And this Experiment taught us among other things that it was a work of more time and labour than we imagin'd to exhaust our Engine as much as it may be exhausted for although before the emerging of the small Viol we did as hath been touch'd already think we had very considerably emptied the Receiver because there seem'd to come out but very little or almost no sensible Air at each exsuction into and out of the Cylinder yet afterwards at each drawing down the Sucker the Air included in the Viol did manifestly dilate it self so long that it did no less than nine times turn its mouth upwards and discharge a bubble by conjecture about the bigness of a Pea after the manner newly recited But as for that Viol which had the weight in it it rose not at all So that being not able by quick pumping to gain another bubble from the Air in the swimming Glass which proceeded from some small leak in the Vessel though it held in this Experiment more stanch than was usual we thought fit to let in leasurely the Air from without upon whose admission that within the Viol shrinking into a very narrow compass the Glass did as we expected fall down to the bottom of the Jar. But being desirous before we proceed to any new Experiment to try once more whether the little Glass that had the weight in it might not also be rais'd After we had suffer'd the Engine to remain clos'd as it was for five or six hours the Pump was again ply'd with so much obstinacy that not onely about the upper part of the Jar there appear'd a good number of bubbles but very much smaller than those we saw the first time but afterwards there came from the bottom of the Jar bubbles about the bigness of small Peas which the Pump being still kept going follow'd one another to the number of forty coming from the stopp'd Viol whose mouth it seems had not been shut so strongly and closely but that the included Air dilating it self by its own spring made it self some little passage betwixt the Wax and the Glass and got away in these bubbles after which the unstopt Glass began to float again the Air shut up in it being manifestly so dilated as to expel a good part of the Water but not so much as to break quite thorough And at length when our expectation of it was almost tired out the heavier of the two Viols began to come alost and immediately to subside again which appear'd to be occasion'd by the Air within it whose bulk and spring being weaken'd by the recess 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 Glass boyed it up towards the top and there getting away left it to sink again till the pressure of the Air in the Receiver being farther taken off the Air in the Viol was permitted to expand it self farther and to create another bubble by which it was again for a while carried up And it was remarkable that though after having emptied the Receiver as far as well we could we ceased from pumping yet the Vessel continuing more stanch than it was wont this ascent and fall of the Viol was repeated to the ninth time the included Air by reason of the smallness of the vent at which it must pass out being not able to get away otherwise than by little and little and consequently in divers such parcels as were able to constitute bubbles each of them big enough to raise the Viol and keep it alost untill the avolation of that bubble Whereby it may appear that the grand rule in Hydrostaticks That a Body will swim in the Water in case it be lighter than as much of the Water as equals it in bulk will hold likewise when the pressure of the Atmosphere is in very great measure if not when it is totally taken off from the Liquor and the Body though it were worth inquiring what it is that so plentifully concurs to fill the bubbles made in our Experiment by the so much expanded Air. For to say with the old Peripatetick Schools That the Air in rarefaction may acquire a new extent without the admission of any new substance would be an account of the Phaenomenon very much out of date and which I suppose our Modern Naturalists would neither give nor acquiesce in I know not whether it may be requisite to add that in this Experiment as in the former the outward Air being let in did soon precipitate the floating Viol. But I think it will not be amiss to note that congruously to what hath been above recorded of the vast expansion of the Air the Water which in the heavier Viol succeeded in the room of those forty odd if not fifty great bubbles of Air which at several times got out of it amounted but to a very inconsiderable bigness EXPERIMENT XXVI IT having been observ'd by those that have consider'd what belongs to Pendulums a Speculation that may in my poor judgment be highly usefull to the Naturalists that their Vibrations are more slowly made and that their motion lasts less in a thicker than in a thinner Medium We thought it not
pointed at by our Experiments in the common Doctrine of those Plenists we reason with for many of those unusual motions in Bodies that are said to be made to escape a Vacuum seem rather made to fill it For why to instance in our newly mention'd Experiment as soon as the Valve was depressed by the weight we hung at it should the Air so impetuously and copiously rush 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 those little spaces in the Receiver which the corpuscles of that Air afterwards fill'd may be concluded to have remain'd empty So that the seeming violence imploy'd by Nature on the occasion of the evacuating of the Vessel seems to have come too late to hinder the making of Vacuities in the Receiver and only to have as soon as we permitted fill'd up with Air those that were already made And as for the care of the publique good of the Universe ascrib'd to dead and stupid Bodies we shall only demand why in our 19th Experiment upon the Exsuction of the ambient Air the Water deserted the upper half of the Glass-Tube and did not ascend to fill it up till the external Air was let in upon it whereas by its easie and sudden regaining that upper part of the Tube it appeared both that there was there much space devoid of Air and that the Water might with small or no resistance have ascended into it if it could have done so without the impulsion of the re-admitted Air which it seems was necessary to mind the Water of its formerly neglected Duty to the Universe Nay for ought appeareth even when the excluded Air as soon as 't was permitted rush'd violently into our exhausted Receiver that flowing in of the Air proceeded rather from the determinate Force of the Spring of the neighbouring Air than from any endeavour to fill up much less to prevent vacuity's For though when as much Air as will is gotten into our Receiver our present Opponents take it for granted that it is full of Air yet if it be remembred that when we made our 17th Experiment we crouded in more Air to our Receiver than it usually holds and if we also consider which is much more that the Air of the same consistence with that in our Receiver may in Wind-guns as is known and as we have tryed be compressed at least into half its wonted room I say at least because some affirm that the Air may be thrust into an 8th or a yet smaller part of its ordinary extent it seems necessary to admit either a notion of condensation and rarefaction that is not intelligible or that in the capacity of our Receiver when presumed to be full of Air there yet remain'd as much of space as was taken up by all the Aërial corpuscles unpossessed by the Air. Which seems plainly to infer that the Air that rush'd into our empty'd vessel did not doe it precisely to fill up the Vacuities of it since it left so many unfill'd but rather was thrust in by the pressure of the contiguous Air which as it could not but be always ready to expand it self where it found least resistance so was it unable to fill the Receiver any more than untill the Air within was reduc'd to the same measure of Compactness with that without We may also from our two already often mention'd Experiments farther deduce that since Natures hatred of a Vacuum is but Metaphorical and Accidental being but a consequence or result of the pressure of the Air and of the Gravity and partly also of the Fluxility of some other Bodies The power she makes use of to hinder a Vacuum is not as we have else-where also noted any such boundless thing as men have been pleased to imagine And the reasons why in the former Experiments mentioned in favour of the Plenists Bodies seem to forget their own Natures to shun a Vacuum seems to be but this That in the alledged cases the weight of that Water that was either kept from falling or impell'd up was not great enough to surmount the pressure of the contiguous Air which if it had been the Water would have subsided though no Air could have succeeded For not to repeat that Experiment of Monsieur Paschal formerly mention'd to have been tryed in a Glass exceeding 32. Foot wherein the inverted Pipe being long enough to contain a competent-weight of Water that Liquor freely ran out at the lower Orifice Not to mention this I say we saw in our nineteenth Experiment that when the pressure of the ambient Air was sufficiently weakn'd the Water would fall out apace at the Orifice even of a short Pipe though the Air could not succeed into the room deserted by it And it were not amiss if tryal were made on the tops of very high Mountains to discover with what case a Vacuum could be made near the confines of the Atmosphere where the Air is probably but light in comparison of what it is here below But our present three and thirtieth Experiment seems to manifest not onely that the power exercis'd by Nature to shun or replenish a Vacuum is limitted but that it may be determin'd even to Pounds and Ounces Insomuch that we might say such a weight Nature will sustain or will lift up to resist a Vacuum in our Engine but if an Ounce more be added to that weight it will surmount Her so much magnifi'd detestation of Vacuities And thus My Lord our Experiments may not onely answer those of the Plenists but enable us to retort their Arguments against themselves since if that be true which they alleadge that when Water falls not down according to its nature in a Body wherein no Air can succeed to fill up the place it must leave the suspension of the Liquor is made Ne detur Vacuum as they speak it will follow that if the Water can be brought to subside in such a case that deserted space may be deem'd empty according to their own Doctrine especially since Nature as they would perswade us bestirs her self so mightily to keep it from being deserted I hope I shall not need to remind Your Lordship that I have all this while been speaking of a Vacuum not in the strict and Philosophical sense but in that more obvious and familiar one that hath been formerly declar'd And therefore I shall now proceed to observe in the last place that our 33d Experiment affords us a notable proof of the unheeded strength of that pressure which is sustain'd by the Corpuscles of what we call the free Air and presume to be uncompressed For as fluid and yielding a Body as it is our Experiment teacheth us That ev'n in our Climate and without any other compression than what is at least here below Natural or to speak more properly ordinary to it it bears so strongly upon the Bodies whereunto it is
was wetted beforehand the Water would rise much better than otherways But we caus'd not all our slender Pipes to be made streight but some of them crooked like Siphons And having immers'd the shorter Leg of one of these into a Glass that held some fair Water we found as we expected that the Water arising to the top of the Siphon though that were high enough did of it self run down the longer Leg and continue running like an ordinary Siphon The cause of this ascension of the Water appear'd to all that were present so difficult that I must not stay to enumerate the various Conjectures that were made at it much less to examine them especially having nothing but bare Conjectures to substitute in the room of those I do not approve We try'd indeed by conveying a very slender Pipe and a small Vessel of Water into our Engine whether or no the exsuction of the ambient Air would assist us to find the cause of the ascension we have been speaking of But though we imploy'd red Wine instead of Water yet we could scarce certainly perceive thorow so much Glass as was interpos'd betwixt our eyes and the Liquor what happen'd in a Pipe so slender that the redness of the Wine was scarce sensible in it But as far as we could discern there happen'd no great alteration to the Liquor which seem'd the less strange because the spring of that Air that might depress the Water in the Pipe was equally debilitated with that which remain'd to press upon the surface of the Water in the little Glass Wherefore in favor of his Ingenious Conjecture who ascrib'd the Phaenomenon under consideration to the greater pressure made upon the water by the Air without the Pipe than by that within it where so much of the Water consisting perhaps of Corpuscles more pliant to the internal surfaces of the Air was contiguous to the Glass it was shown that in case the little Glass Vessel that held the water of which a part ascended into the slender Pipe were so clos'd that a Man might with his mouth suck the Air out of it the water would immediately subside in the small Pipe And this would indeed infer that it ascended before onely by the pressure of the incumbent Air But that it may how justly I know not be objected That peradventure this would not happen in case the upper end of the Pipe were in a Vacuum And that 't is very probable the water may subside not because the pressure of the internal Air is taken off by Exsuction but by reason of the spring of the external Air which impels the Water it findes in its way to the cavity deserted by the other Air and would as well impel the same water upwards as make it subside if it were not for the accidental posture of the Glasses However having not now leisure to examine any farther this Matter I shall onely mind Your Lordship that if You will prosecute this Speculation it will be pertinent to find out likewise Why the surface of water as is manifest in Pipes useth to be concave being depress'd in the middle and higher on every side and why in Quicksilver on the contrary not onely the surface is wont to be very convex or swelling in the middle but if you dip the end of a slender Pipe in it the surface of the Liquor as 't is call'd will be lower within the Pipe than without Which Phaenomena whether and how far they may be deduc'd from the Figure of the mercurial Corpuscles and the Shape of the springy Particles of the Air I willingly leave to be consider'd EXPERIMENT XXXVI SEveral ways we have met with propos'd partly by the excellent Galileo and partly by other ingenious Writers to manifest that the Air is not devoid of weight some of these require the previous absence of the Air to be weighed and others the violent condensation of it But if we could list a pair of Scales above the Atmosphere or place them in a Vacuum we might there weigh a parcel of Air it self as here we do other Bodies in the Air because it would there be heavier than that which surrounds it as are grosser Bodies we commonly weigh than the medium or ambient Air. Wherefore though we have above declin'd to affirm that our Receiver when emptyed deserves the name of a true Vacuum and though we cannot yet perfectly free it from Air it self yet we thought fit to try how far the Air would manifest its gravity in so thin a medium as we could make in our Receiver by evacuating it We caus'd then to be blown at the Flame of a Lamp a Glass bubble of about the bigness of a small Hen-egge and of an Oval form save that at one end there was drawn out an exceeding slender Pipe that the Bubble might be sealed up with as little rarefaction as might be of the Air included in the great or Oval Cavity of it This Glass being sealed was fastened to one of the Scales of the exact pair of Ballances formerly mention'd and being counterpois'd with a weight of Lead was convey'd into the Receiver and clos'd up in it The Beam appearing to continue Horizontal the Pump was set on work and there scarce past above two or three Exsuctions of the Air before the Ballance lost its Equilibrium and began to incline to that side on which the Bubble was which as the Air was farther and farther drawn out did manifestly more and more preponderate till he that pumped began to grow weary of his Imployment after which the Air being leisurely let in againe the Scales by degrees returned to their former Equilibrium After that we took them out and casting into that Scale to which the lead belonged three quarters of a grain we conveyed the ballance into the Receiver which being closed up and exhausted as before we observ'd that as the Air was drawn out more and more so the Glass bubble came nearer and nearer to an Equilibrium with the other weight till at length the Beam was drawn to hang Horizontal which as we had found by another tryal we could not bring it to do when a quarter of a Grain more was added to the Scale to which the Lead belong'd though it seem'd questionless that if we could have perfectly empty'd the Receiver of the contain'd Air that included in the bubble would have weighed above a Grain notwithstanding its having been probably somewhat rarefied by the flame by the help of which the bubble was seal'd up Let us adde That on the regress of the excluded Air the Lead and the weight cast into the same scale did again very much preponderate We likwise convey'd into the Receiver the same bubble open'd at the end of the slender Pipe above-mention'd but having drawn out the Air after the accustomed manner we found not as before the bubble to out-weigh the opposite Lead so that by the help of our Engine we can weigh the Air as we
weigh other Bodies in its natural or ordinary consistence without at all condensing it Nay which is remarkable having convey'd a Lambs bladder about half full of Air into the Receiver we observed that though upon the drawing out of the ambient Air the imprisoned Air so expanded it self as to distend the Bladder so as to seem ready to Break it yet this rarefied Air did manifestly depress the Scale whereunto it was annexed Another thing we must not forget to mention that happened to us whilst we were making tryals concerning the weight of the Air namely that having once caus'd the Pump to be somewhat obstinately ply'd to discover the better what may be expected from the thinness of the medium in this Experiment the Imprison'd Air broke its brittle Prison and throwing the greatest part of it against the side of the Receiver dash'd it against that thick Glass into a multitude of pieces Which accident I mention partly that it may confirm what we deliver'd in our Reflexions upon the first Experiment where we considered what would probably be done by the spring of the Air Imprison'd in such Glasses in case the ballancing pressure of the ambient Air were withdrawn and partly that we may thence discern of how close a Texture Glass is since so very thin a film of Glass if I may so call it prov'd so impervious to the Air that it could not get away through the Pores but was forc'd to break the Glass in pieces to free it self and this notwithstanding the time and advantage it had to try to get out at the Pores And this I mention that neither our Experiments nor those of divers Learned Men might receive any prejudice from an Experiment which I happen'd to make divers years ago and which having been so much taken notice of by curious Men may be drawn to countenance their erroneous Opinion who would fain perswade us That Glass is penetrable by Air properly so called Our Experiment was briefly this We were distilling a certain Substance that much abounded with subtle Spirits and volatile Salt in a strong Earthen vessel of an unusual shape to which was luted a large Receiver made of the course sort of Glass which the Trades-men are wont to call green Glass but in our absence the Fire though it were to be very strong was by the negligence or mistake of those we appointed to attend it so excessively increas'd that when we came back to the Fornace we found the spirituous and saline Corpuscles pour'd out if I may so call it so hot and so copiously into the Receiver that they made it all opacous and more likely to flie in pieces than fit to be touch'd Yet being curious to observe the effects of a Distillation prosecuted with so intense and unusual a degree of heat we ventur'd to come near and observ'd among other things that on the outside of the Receiver at a great distance from the juncture there was setled a round whitish Spot or two which at first we thought might be some stain upon the Glass but after finding it to be in divers Qualities like the Oyl and Salt of the Concrete we were Distilling we began to suspect that the most subtle and fugitive parts of the impetuously ascending Steams had penetrated the substance as they speak of the Glass and by the cold of the ambient Air were condensed on the surface of it And though we were very backward to credit this suspition and therefore call'd in an Ingenious Person or two both to assist us in the Observation and have Witness of its event we continued a while longer to watch the escape of such unctuous Fumes and upon the whole matter unanimously concluded that all things consider'd the subtle parts of the distill'd matter being violently agitated by the excessive heat that pass'd through the Pores of the Glass widn'd by the same heat But this having never happen'd but once in any of the Distillations we have either made or seen though these be not a few it is much more reasonable to suppose that the perviousness of our Receiver to a Body much more subtle than Air proceeded partly from the looser Texture of that particular parcel of Glass the Receiver was made of for Experience hath taught us that all Glass is not of the same compactness and solidity and partly from the enormous heat which together with the vehement agitation of the penetrant Spirits open'd the Pores of the Glass than to imagine that such a substance as Air should be able to permeate the Body of Glass contrary to the testimony of a thousand Chymical and Mechanical Experiments and of many of those made in our Engine especially that newly recited Nay by our fifth Experiment it appears that a thin Bladder will not at its Pores give passage even to rarefied Air. And on this occasion we will annex an Experiment which hath made some of those we have acquainted with it doubt whether the Corpuscles of the Air be not less subtle than those of Water But without examining here the reasonableness of that doubt we will proceed to recite the Experiment it self which seems to teach That though Air when sufficiently compressed may perchance get entrance into narrower holes and crannies than Water yet unless the Air be forc'd in at such very little holes it will not get in at them though they may be big enough to let Water pass through them The Experiment then was this I took a fair Glass Siphon the lower end of whose longest Leg was drawn by degrees to such a slenderness that the Orifice at which the Water was to fall out would hardly admit a very small Pin This Siphon being inverted the matter was so order'd that a little Bubble of Air was intercepted in the slenderest part of the Siphon betwixt the little hole newly mention'd and the incumbent Water upon which it came to pass that the Air being not to be forc'd through so narrow a passage by so light a Cylinder of Water though amounting to the length of divers Inches as lean'd upon it hindered the farther efflux of the Water as long as I pleased to let it stay in that narrow place whereas when by blowing a little at the wider end of the Siphon that little parcel of Air was forced out with some Water the remaining Water that before continu'd suspended began freely to drop down again as formerly And if you take a Glass Pipe whether it be in the form of a Siphon or no that being for the most part of the thickness of a Mans Finger is yet towards one end so slender as to terminate in a hole almost as small as a Horse-hair and if you fill this Pipe with Water you will find that Liquor to drop down freely enough thorow the slender Extream But if you then invert the Pipe you will find that the Air will not easily get in at the same hole through which the Water passed For in the sharp end
So that being unable to give an account of these odd changes in our Tincture which we suppose we have not yet lost though we know not whether it hath lost its fickle Nature either by those of the Air or any thing else that occurr'd to our thoughts we could not but suspect that there may be in divers Bodies as it were Spontaneous Mutations that is such changes as depend not upon manifest Causes But My Lord what hath been all this while said concerning our Phaenomenon is offer'd to You not as containing a satisfactory account of it but to assist You to give Your self one EXPERIMENT XXXVIII WE took a Glass Vessel open at the top and into it we put a mixture of Snow and common Salt such a mixture as we have in another Treatise largely discoursed of and into the midst of this mixture we set a Glass of a Cylindrical form closely stopp'd at the lower end with Plaister and open at the upper at which we fill'd it with common Water These things being let down into the Receiver and the Pump being set on work the Snow began to melt somewhat faster than we expected Whether upon the account of the exsuction of the Air or because there was but little of the Snow or whether for any other Reason it appear'd doubtfull But however by that time the Receiver had been considerably exhausted which was done in less than ¼ of an hour we perceived the Water near the bottom of the Glass Cylinder to Freeze and the Ice by a little longer stay seem'd to encrease and to rise somewhat higher than the surface of the surrounding Liquor whereinto almost all the Snow and Salt were resolv'd The Glass being taken out it appear'd that the Ice was as thick as the inside of the Glass it fill'd though into that I could put my Thumb The upper surface of the Ice was very concave which whether it were due to any unheeded accident or to the exsuction of the Air we leave to be determin'd by farther trial And lastly the Ice held against the Light appear'd not destitute of Bubbles though some By-standers thought they were fewer than would have been found if the Water had been frozen in the open Air. The like Experiment we try'd also another time in one of our small Receivers with not unlike success And on this occasion My Lord give me leave to propose a Problem which shall be this Whence proceeds that strange force that we may sometimes observe in frozen Water to break the Bodies that imprison it though hard and solid That there is such a force in Water expos'd to Congelation may be gathered not only from what may be often observ'd in Winter of the bursting of Glasses too close stopp'd fill'd with Water or aqueous Liquors but by Instances as much more considerable as less obvious For I remember that an Ingenious Stone-cutter not long since complain'd to me That sometimes through the negligence of Servants the Rain being suffered to soak into Marble Stones the supervening violent Frosts would burst the Stones to the Possessour's no small damage And I remember another Trades-man in whose House I had Lodgings was last Winter complaining that even Implements made of Bell-metal being carelesly expos'd to the wet have been broken and spoil'd by the Water which having gotten into the little Cavities and Crannies of the Metal was there afterwards frozen and expanded into Ice And to these Relations we can add one of the formerly mention'd Cabaeus's whereby they not only may be confirm'd but are surpass'd For he tells us That he saw a huge Vessel of exceeding hard Marble split asunder by congeal'd Water whose rarefaction saith our Author prov'd so vehement that the hardness of the Stone yielded to it and so a vessel was broken which would not have been so by 100 Yoke of Oxen drawing it several ways I know My Lord that to solve this Problem it will be said That Congelation doth not as is commonly but erroneously presum'd reduce Water into less room than it possess'd before but rather makes it take up more And I have elsewhere prov'd by particular Experiments That whether or no Ice may be truly said to be Water rarefi'd for that seems questionable it may be said to take up more room than the Water did before Glaciation But though we grant that freezing makes Water swell yet how cold which in Weather-Glasses manifestly condenseth the Air should expand either the Water or the intercepted Air so forcibly as to perform such things as we have newly related will yet remain a Problem EXPERIMENT XXXIX WE took an Oval Glass clear and lest it should break pretty strong with a short Neck at the obtuser end through this Neck we thrust almost to the bottom a Pipe of Glass which was closely cemented to the newly mention'd Neck the upper part of which Pipe was drawn in some places more slender than a Crows Quill that the changes of the Air in that Glass Egg might be the more conspicuous Then there was convey'd into the Glass five or six Spoon-fulls of Water part of which by blowing Air into the Egg was rais'd into the above-mention'd slender part of the Pipe so that the Water was interpos'd between the external Air and that included in the Egg. This Weather glass delineated in the fourteenth Figure was so plac'd and clos'd up in the cavity of one of our small Receivers that only the slender part of the Pipe to the height of four or five Inches passing thorow a hole in the Cover remain'd expos'd to the open Air. The Pump being set a work upon the exsuction of the Air the Water in the Pipe descended about a quarter of an Inch and this upon two or three reiterated trials which seem'd sufficiently to argue that there was no heat produc'd in the Receiver upon the exsuction of the Air For even a little heat would probably have been discover'd by that Weather-glass since upon the bare application of my hand to the outside of the Receiver the warmth having after some time been communicated or propagated through both the Glasses and the interval betwixt them to the imprison'd Air did so rarefie that as to inable it by pressing upon the subjacent Water to impel that in the Pipe very many times as far as it had fallen downwards upon the exsuction of the Air. Yet shall not we conclude that in the cavity of the Receiver the cold was greater after the exsuction of the Air than before For if it be demanded what then could cause the fore-mention'd subsiding of the Water it may be answered That probably it was the reaching of the Glass Egg which upon the exsuction of the ambient Air was unable to resist altogether as much as formerly the pressure of the included Air and of the Atmosphere which by the intervention of the Water press'd upon its concave surface Which seem'd probable as well by what was above deliver'd in the Experiment about
moderate heat than such an excessive one as needs to be perpetually cool'd to keep it from growing destructive which the gentle and not the burning heat of an Animal's Heart seems not intense enough so indispensably to require These and other Objections might be oppos'd and press'd against the recited Opinion But we shall not insist on them but only add to them That it appears not by our foregoing Experiments I mean the 38th and 39th that in our exhausted Receiver where yet Animals die so suddenly for want of Respiration the ambient Body is sensibly hotter than the common Air. Other Learned Men there are who will have the very substance of the Air to get in by the Vessels of the Lungs to the left Ventricle of the Heart not only to temper its heat but to provide for the generation of Spirits And these alledge for themselves the authority of the Ancients among whom Hippocrates seems manifestly to favour their Opinion and both Aristotle and Galen do sometimes for methinks they speak doubtfully enough appear inclineable to it But for ought ever I could see in Dissections it is very difficult to make out how the Air is convey'd into the left Ventricle of the Heart especially the Systole and Diastole of the Heart and Lungs being very far from being Synchronical Besides that the Spirits seeming to be but the most subtle and unctuous Particles of the Blood appear to be of a very differing Nature from that of the lean and incombustible Corpuscles of Air. Other Objections against this Opinion have been proposed and press'd by that excellent Anatomist and my Industrious Friend Dr. Highmore to whom I shall therefore refer you Another Opinion there is touching Respiration which makes the genuine use of it to be Ventilation not of the Heart but of the Blood in its passage through the Lungs in which passage it is dis-burthened of those Excrementitious Steams proceeding for the most part from the superfluous Serosities of the Blood we may add and of the Chyle too which by those new Conduits of late very happily detected by the Famous Pecquet hath been newly mix'd with it in the Heart And this Opinion is that of the Industrious Maebius and is said to have been that of that excellent Philosopher Gassendus and hath been in part an Opinion almost vulgar But this Hypothesis may be explicated two ways For first The necessity of the Air in Respiration may be suppos'd to proceed from hence That as a Flame cannot long burn in a narrow and close place because the Fuliginous Steams it uncessantly throws out cannot be long receiv'd into the ambient Body which after a while growing too full of them to admit any more stifles the flame So that the vital Fire in the Heart requires an ambient Body of a yielding nature to receive into it the superfluous Serosities and other Recrements of the Blood whose seasonable Expulsion is requisite to depurate the Mass of Blood and make it fit both to circulate and to maintain the vital heat residing in the Heart The other way of explicating the above-mentioned Hypothesis is by supposing that the Air doth not only as a Receptacle admit into its Pores the Excrementitious vapours of the Blood when they are expell'd through the Wind-pipe but doth also convey them out of the Lungs in regard that the inspired Air reaching to all the ends of the Aspera Ateria doth there associate it self with the exhalations of the circulating Blood and when 't is exploded carries them away with it self as we see that Winds speedily dry up the surfaces of wet Bodies not to say any thing of what we formerly observed touching our Liquor whose fumes were strangely elevated upon the ingress of the Air. Now of these two ways of Explicating the use of Respiration our Engine affords us this Objection against the first That upon the exsuction of the Air the Animals die a great deal sooner than if it were left in the Vessel though by that exsuction the ambient space is left much more free to receive the Steams that are either breathed out of the Lungs of the Animal or discharg'd by insensible Transpiration through the Pores of his Skin But if the Hypothesis propos'd be taken in the other sense it seems congruous enough to that grand observation which partly the Phaenomena of our Engine and partly the relations of Travellers have suggested to us namely That there is a certain consistence of Air requisite to Respiration so that if it be too thick and already over-charged with Vapours it will be unfit to unite with and carry off those of the Blood as Water will dissolve and associate to it self but a certain proportion of saline Corpuscles and if it be too thin or rarefied the number or size of the Aërial Particles is too small to be able to assume and carry off the halituous Excrements of the Blood in such plenty as is requisite Now that Air too much thicken'd and as it were clogg'd with Steams is unfit for Respiration may appear by what is wont to happen in the Lead-Mines of Devonshire and for ought I know in those too of other Countries though I have seen Mines where no such thing was complain'd of for I have been informed by more than one credible Person and particularly by an Ingenious Man that hath often for curiosity digg'd in those Mines and been imploy'd about them that there often riseth Damps as retaining the Germane Word by which we call them which doth so thicken the Air that unless the Work-men speedily make signs to them that are above they would which also sometimes happens be presently stifled for want of Breath and though their Companions do make haste to draw them up yet frequently by that time they come to the free Air they are as it were in a swoon and are a good while before they come to themselves again And that this swooning seems not to proceed from any Arsenical or Poysonous Exhalation contain'd in the Damp as from its overmuch condensing the Air seems probable from hence That the same Damps oftentimes leisurely extinguish the flames of their Candles or Lamps and from hence also that it appears by many Relations of Authentical Authors that in those Cellars where great store of new Wine is set to work Men have been suffocated by the too great plenty of the Steams exhaling from the Must and too much thickning the Air As may be gathered from the custom that is now used in some hot Countries where those that have occasion to go into such Cellars carry with them a quantity of well kindled Coals which they hold near their Faces whereby it comes to pass that the Fire discussing the Fumes and rarefying the Air reduceth the ambient Body to a consistence fit for Respiration We will add by way of Confirmation the following Experiment In such a small Receiver as those wherein we kill'd divers Birds we carefully clos'd up one who though for a
reflect upon the wise goodness of the Creator who by giving the Air a spring hath made it so very difficult as Men find it to exclude a thing so necessary to Animals And it gave us also occasion to suspect that if Insects have no Lungs nor any part analogous thereunto the ambient Air afsects them and relieves them at the Pores of their skin it not being irrational to extend to these Creatures that of Hippocrates who saith That a living Body is throughout perspirable or to use his expression 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 dispos'd to admit and part with what is Spirituous Which may be somewhat illustrated by what we have elsewhere noted That the moister parts of the Air readily insinuate themselves into and recede from the pores of the Beards of wild Oats and those of divers other wild Plants which almost continually wreath and unwreath themselves according to even the light variations of the temperature of the ambient Air. This Circumstance of our Experiment we particularly took notice of that when at any time upon the ingress of the Air the Bee began to recover the first sign of Life she gave was a vehemen panting which appear'd near the Tail Which we therefore mention because we have observ'd the like in Bees drown'd in Water when they first come to be reviv'd by a convenient heat As if the Air were in the one case as proper to set the Spirits and Alimental Juice moving as heat is in the other and this may perchance deserve a farther consideration We may add That we scarce ever saw any thing that seem'd so much as this Experiment to manifest That even living Creatures Man always excepted are a kind of curious Engines fram'd and contriv'd by nature or rather the Author of it much more skilfully than our gross Tools and imperfect Wits can reach to For in our present Instance we see Animals vivid and perfectly sound depriv'd immediately of motion and any discernable signs of life and reduc'd to a condition that dissers from death but in that it is not absolutely irrecoverable This I say we see perform'd without any so much as the least external violence offer'd to the Engine unless it be such as is offered to a Wind-Mill when the Wind ceasing to blow on the Sails all the several parts remain moveless and useless till a new Breath put them into motion again And this was farther very notable in this Experiment That whereas 't is known that Bees and Flies will not only walk but flie for a great while after their heads are off and sometimes one half of the Body will for divers hours walk up and down when it is sever'd from the other Yet upon the exsuction of the Air not only the progressive motion of the whole Body but the very motions of the Limbs do forthwith cease as if the presence of the Air were more necessary to these Animals than the presence of their own Heads But it seems that in these Insects that fluid Body whether it be a Juice or Flame wherein Life chiefly resides is nothing neaŕ so easily dissipable as in perfect Animals For whereas we have above-recited That the Birds we conveyed into our small Receiver were within two minutes brought to be past recovery we were unable though by trying him that pump'd to kill our Insects by the exsuction of the Air For though as long as the Pump was kept moving they continued immovable yet when he desisted from pumping the Air that press'd in at the unperceiv'd Leaks did though slowly restore them to the free exercise of functions of Life But My Lord I grow troublesome and therefore shall pass on to other Experiments Yet without despairing of your pardon for having entertain'd you so long about the use of Respiration because it is a subject of that difficulty to be explain'd and yet of that importance to humane Life that I shall not regret the trouble my Experiments have cost me if they be found in any degree serviceable to the purposes to which they were design'd And though I despair not but that hereafter our Engine may furnish us with divers Phaenomena usefull to illustrate the Doctrine of Respiration yet having not as yet had the opportunity to make the other trials of various kinds that I judge requisite for my Information I must confess to Your Lordship that in what I have hitherto said I pretend not so much to establish or over-throw this or that Hypothesis as to lay together divers of the Particulars that occurr'd to me in order to a future inquiry I say divers of the Particulars because I could add many others but that I want time and fear that I shall need Your Lordship's pardon for having been so prolix in writing and that of Physicians which perhaps I shall more easily obtain for having invaded Anatomy a Discipline which they challenge to themselves and indeed have been the almost sole Improvers of Without denying then that the inspir'd and exspir'd Air may be sometimes very usefull by condensing and cooling the Blood that passeth through the Lungs I hold that the depuration of the Blood in that passage is not only one of the ordinary but one of the principal uses of Respiration But I am apt also to suspect that the Air doth something else in Respiration which hath not yet been sufficiently explain'd and therefore till I have examin'd the matter more deliberately I shall not scruple to answer the Questions that may be asked me touching the genuine use of Respiration in the excellent Words employ'd by the acute St. Austin to one that ask'd him hard Questions Mallem quidem says he eorum quae à me quaesivisti habere scientiam quam ignorantiam sed quia id nondum potui magis eligo cautam ignorantiam confiteri quam falsam scientiam profiteri EXPERIMENT XLII HAving partly upon the consideration of some of the foregoing Experiments and partly upon grounds not now to be insisted on entertain'd a suspicion that the action of Corrosive Liquors in the dissolving of Bodies may be considerably varied by the gravitation or pressure of the incumbent Air and the removal of it I thought fit to examine my Conjecture by the following Experiment I took whole pieces of red Coral and cast them into as much spirit of Vineger as sufficed to swim above an Inch over them These substances I made choice of that the Ebullition upon the Solution might not be too great and that the operation might last the longer Having then put about half a score sprigs of Coral together with the Menstruum into a somewhat long neck'd Viol whereof they seem'd scarce to fill a third part we convey'd that Viol into one of our small Pneumatical Glasses containing by ghess about a Quart of Water and having fastned on the Cover after the accustom'd manner we suffered the Liquor to remain unmov'd a while to observe whether the Menslruum would work upon the Coral otherwise than besore But
the restagnant Mercury So that the Air included and endeavouring to expand it self finding no assistance to expand it self upward and a considerable one to expand it self downward it is very natural that it should expand it self that way whence it finds less resistance As accordingly it will happen till the Spring of the Air be so far debilitated by its Expansion that its pressure together with the weight of the Mercury that remains suspended will but counter-balance not overcome the pressure of the outward Air upon the restagnant Mercury And this explication may be confirm'd by this trial that I have purposely made namely that if in stead of Quicksilver you employ Water and leave as before in the Tube an Inch of Air and then inverting it open it under Water you will perceive the included Inch of Air not to dilate it self any thing near for I need not here define the Proportion half so far as it did when the Tube was almost fill'd with Mercury because the Weight of so short a Cylinder of Water does but equal that of between an Inch and an Inch and an half onely of Quicksilver and consequently the inward Air is far less assisted to dilate it self and surmount the pressure of the outward Air by the Cylinder of Water than by that of Mercury And as for what our Author sayes that if instead of Air Water or some other Liquor be left at the top of the Tube the Quicksilver will not descend the Elaterists can readily solve that Phaenomenon by saying that Water has either no Spring at all or but an exceeding weak one and so scarce presses but by its Weight which in so short a Cylinder is inconsiderable Now the same solution we have given of our Examiners Objection gives us also an account why the Finger is so strongly fastned to the upper part of the Orifice of the Tube it stops for the included Air being so far dilated that an Inch for example left at first in the upper Part of the Tube reaches twice or thrice as far as it did before the descent of the Quicksilver its spring must be proportionably weakned And consequently that part of the Finger that is within the Tube will have much les pressure against it from the dilated Air within than the upper part of the same Finger will have from the unrarefi'd Air without By which means the Pulp of the Finger will be thrust in which our Author is pleas'd to call suckt in as we shall ere long have occasion to declare in our Answer to his second Argument And having said thus much to our Authors first exception against the solution he foresaw we would give of his third Argument we have not much to say at present to this second For whereas he sayes Concipi non posse quomodo aër ille sic se dilatet argentumque deorsum trudat nisi occupando majorem locum Quod tamen hi Authores quam maxime refugiunt asserentes rarefactionem non aliter fieri quam per corpuscula aut vacuitates I wish he had more clearly express'd himself since as his words are couch'd I cannot easily guess what he means and much less easily discern how they make an Argument against his Adversaries For sure he thinks them not so absurd as to imagine that the Air can dilate it self and thrust down the Mercury without in some sense taking up more room than it did before For the very word Dilatation and the effect they ascribe to the included Air clearly imply as much so that I see not why he should say that they are so averse from granting the Air to take up more Place than before especially since he takes notice in the former Chapter that we compare the Expansion of the Air to that of compress'd Wooll and since he here also annexes that we explicate Rarefaction either by Corpuscles or Vacuities But this later Clause makes me suspect his meaning to be that the Elaterists do not admit that the same Air may adequately fill more of Place at one time than at another which I believe to be as true as that the self-same lock of compress'd Wooll has no more Hairs in it nor does adequately fill more Place with them when it is permitted to expand it self than whilst it remain'd compress'd But against this way of Rarefaction our Author here has not any Objection unless it be intimated in these words Concipi non potest Which if it be I shall need onely to mind him in this place that whereas many of the chiefest Philosophers both of Ancient and our own times have profest they thought not the Aristotelean way of Rarefaction conceivable and he acknowledges as we shall see anon that it is not clear what the ablest of his Party the modern Plenists are wont to object against the way of Rarefaction he dislikes is that it is not true not that it is not intelligible CHAP. III. OUR Authors Second Objection for so I reckon it is thus propos'd by him Si sumatur tubus utrinque apert us sed longior puta digitorum 40. Argentoque impleatur eique digitus supernè applicatur ut prius videbimus subtracto inferiore digito argentum quidem descendere usque ad consuetam suam stationem Digitum autem superiorem fortiter intra tubum trahi eique firmissime ut prius adhaerere Ex quo rursum evidenter concluditur argentum in sua statione constitutum non ibidem sustentari ab externo aëre sed à funiculo quodam interno suspendi cujus superior extremitas digito affixa eum sic intra tubum trahit eique affigit But this Argument being much of the same nature with that drawn from his third Experiment the Answer made to that and to his first may be easily apply'd and will be sufficient for this also especially because in our present case there is less Pressure against the Pulp of the Finger in the inside of the Tube than in the third Experiment where some Air is inoluded though much expanded and weakned the Pressure of the Atmosphere being in the present case kept off from it by the subjacent Mercury whereas there is nothing of that Pressure abated against the other parts of the Finger that kept it off from the deserted Cavity of the Tube save onely that from the Pulp that is contiguous to the Tube there may be somewhat of that Pressure taken off by the Weight of the Glass it self But as for that Part of the Finger which immediately covers the hole whether or no there be any Spring in its own fibres or other constituent substances which finding no resistance in the place deserted by the Quicksilver may contribute to its swelling for that we will not now examine he that has duly consider'd the account already given of this Intrusion of the Pulp into the Glass will find no need of our Authors internal Funiculus which to some seems more difficult to conceive than any of the
in that Hypothesis it can scarce be otherwise Wherefore I shall only add on this occasion that 't is not clear to me that even such a divisibility of a continuum as is here supposed would make out the Rarefaction he contends for For let the integrant parts of a continuum be more or less finite or infinite in number yet still each part being a corporeal substance must have some Particle of space commensurate to it and if the whole Body be rarefied for instance to twice its former bigness then will each part be likewise extended to double its former dimensions and fill both the place it took up before and another equal to it and so two places The second Argument alledged to recommend the hitherto-mentioned way of explicating Rarefaction is That many learned Men amongst whom he names two Aquinas and Suarez have taught that the same corporeal thing may naturally be and de facto often is in the souls of Brutes really indivisible and virtually extended But though I pay those two Authors a just respect for their great skill in Scholastical and Metaphysical learning yet the Examiner cannot ignore that I could make a long Catalogue of Writers both ancient and modern at least as well vers'd in natural Philosophy as Saint Thomas and Suarez who have some of them in express words denied this to be naturally possible and others have declared themselves of the same judgment by establishing principles with which this Conceit of the virtual extension of the indivisible Corpuscles is absolutely inconsistent And though no Author had hitherto opposed it yet I that dispute not what this or that man thought but what'tis rational to think should nevertheless not scruple to reject it now and should not doubt to find store of the best Naturalists of the same opinion with me and perhaps among them the Examiner himself who however this acknowledgment may agree with the three following Chapters of his book tells us pag. 160. that Juxta probabiliorem sententiam hujusmodi virtualis extensio rei corporeae concedenda non est utpote soli rei spirituali propria But to conclude at length this tedious Enquiry into the Aristotelean way of Rarefaction which is of so obscure a nature that it can scarce be either proposed or examined in few words I will not take upon me resolutely to affirm which of the two ways of explicating it by Atomes or by Parts infinitely divisible our Author declares himself for But which of them soever it be I think I have shown that he has not intelligibly made it out And I make the less scruple to do so because he himself is so ingenuous as at the close of his discourse of the two ways to speak thus of the Opinion he prefers Praestat communi receptae hactenus in Scholis sententiae insistere quae licet difficultates quidem non clarè solvat iis tamen aperte non succumbit So that in this discourse of Rarefaction to which our Author has so often in the foregoing part of the Book referred us as that which should make good what there seemed the most improbable he has but instead of a probable Hypothesis needlesly rejected substituted a Doctrine which himself dares not pretend capable of being well freed from the difficulties with which it may be charged though I doubt not but other Readers especially Naturalists will think he has been very civil to this obscure Doctrine in saying that Difficultatibus non aperte succumbit As for the other way of explicating Rarefaction namely by supposing that a body is made up of parts indivisible he will not I presume deny but that the Objections we formerly made against it are weighty For according to this Hypothesis which one would think he prefers since he makes use of it in the three or four last Chapters of his Book Necessariò fatendum est says he unam eandemque partem poni in duplici loco adaequate Cum enim indivisibilis sit locumque occupet majorem quam prius necesse est ut tota sit in quolibet punato totius lici sive ut per totum illud spatium virtualiter extendatur So that when hein the very next Page affirms that by this virtual extention of the parts the Difficulties that have for so many Ages troubled Philosophers may be easily solved he must give me leave who love to speak intelligibly and not to admit what I cannot understand to desire he would explain to me what this extensto virtualis is and how it will remove the Difficulties that I formerly charged upon the Aristotelean Rarefaction For the easier consideration of this matter let us resume what we lately supposed namely that in the Magdeburgick Experiment the half Inch of undilated Air consisted of a hundred Corpuscles I demand how the indivisibility of these Corpuscles will qualifie them to make out such a Rarefaction as the Author imagines For what does their being indivisible do in this case but make it the less intelligible how they can fill above a hundred parts of space 'T is easie to foresee he will answer That they are virtually extended But not here to question how their indivisibility makes them capable of being so I demand whether by an Atoms being virtually extended its corporeal substance do really I mean adequately fill more space than it did before or whether it do not for one of the two is necessary If it do then 't is a true and real and not barely a virtual extension And that such an extension will not serve the turn what we have formerly argued against the Peripatetick Rarefaction will evince and our Adversary seems to consess as much by devising this virtual extension to avoid the inconveniences to which he saw his Doctrine of Rarefaction would otherwise plainly appear expos'd But if it be said That when an Atome is virtually extended its corporeal substance fills no more space than before This is but a Verbal shift that may perhaps amuse an unwary Reader but it will scarce satisfie a considering one For I demand how that which is not a substance can fill place and how this improper and but Metaphorical Extension will salve the Phaenomena of Rarefaction as how the half Inch of Air at the top of the fore-mentioned Globe shall without a corporeal extension fill the whole Globe of two thousand times its bigness when the water is suck'd out of it and act at the lower part of the Globe Which last Clause I therefore add because not only our Author teaches pag. 91. and 92. that the whole Globe was filled with a certain thin substance which by its contraction violently snatch'd up the water into which the neck of the Glass was immers'd but in a parallel case he makes it his grand Argument to prove that there is no Vacuum in the deserted part of the Tube in the Torricellian Experiment That the attraction of the Finger cannot be performed but by some real
Body Wherefore till the Examiner do intelligibly explain how a virtual Extension as it is opposed to a corporeal can make an Atome fill twice nay two thousand times more space than it did before I suppose this device of virtual extension will appear to unbiass'd Naturalists but a very unsatisfactory evasion Two Arguments indeed there are which our Adversary offers as proofs of what he teaches The first is That they commonly teach in the Schools that at least divinitus as he speaks such a thing as is pleaded for may be done and that consequently it is not repugnant to the nature of a body But though they that either know me or have read what I have written about matters Theological will I hope readily believe that none is more willing to acknowledge and venerate Divine Omnipotence yet in some famous Schools they teach that it is contrary to the nature of the thing And that men who think so and consequently look not upon it as an object of Divine Omnipotence may whatever he here say without impiety be of a differing mind from him about the possibility of such a Rarefaction as he would here have our Author may perchance think fit to grant if he remember that he himself says a few Pages after Cum tempus sit Ens essentialiter successivum it a ut ne divinitus quidem possint duae ejus partes simul existere c. But not now to dispute of a power that I am more willing to adore than question I say that our Controversie is not what God can do but about what can be done by Natural Agents not elevated above the sphere of Nature For though God can both create and annihilate yet Nature can do neither and in the judgment of true Philosophers I suppose our Hypothesis would need no other advantage to make it be preferred before our Adversaries than that in ours things are explicated by the ordinary course of Nature whereas in the other recourse must be had to miracles But though our Author's way of explicating Rarefaction be thus improbable yet I must not here omit to take notice that his Funiculus supposes a Condensation that to me appears incumbred with no less manifest difficulties For since he teaches that a body may be condens'd without either having any vacuities for the comprest parts to retire into or having Pores filled with any subtile and yielding matter that may be squeez'd out of them it will follow that the parts of the Body to be condens'd do immediately touch each other which supposed I demand how Bodies that are already contiguous can be brought to farther Approximations without penetrating each other at least in some of their part So that I see not how the Examiners Condensation can be perform'd without penetration of dimensions A thing that Philosophers of all Ages have looked upon as by no means to be admitted in Nature And our Author himself speaks somewhere at the same rate where to the Question Why the walls that inclose fired Gun-powder must be blown asunder Respondeo says he haec omnia inde accidere quod pulvis ille sic accensus in flammam conversus longe majus spatium nunc occupet quà m prius Vnde fit ut cum totum cubiculum antea fuerit plenissimum disrumpantur sic parietes ne detur corporum penetratio In the Magdeburgick Experiment he tells us as we have heard already that the whole capacity of the Globe is filled with an extremely-thin body But not now to examine how properly he calls that a rare body which according to him intercepts neither Pores nor any heterogeneous substance the greater or lesser absence of which makes men call a Body more or less dense not to insist on this I say let us consider that before the admission of water into the exhausted Globe there was according to him two thousand half Inches of a substance which however it was produc'd or got thither was a true and real Body and that after the admission of the water there remained in the same Globe besides the water that came in no more than one half Inch of body Since then our Author does not pretend which if he did might be easily disproved that the one thousand nine hundred ninety nine half Inches of Matter that now appear no more traversed the body of Water since he will not allow that it gets away through the Pores of the Glass I demand what becomes of so great a quantity of Matter For that 't is annihilated I suppose he is too rational a man to pretend nor if he should would it be at all believ'd and to say that a thousand and so many hundred parts of Matter should be retir'd into that one part of space that contains the one half Inch of Air is little less incredible For that space was suppos'd perfectly full of body before and how a thing can be more than perfectly full who can conceive To dispatch According to our Author's way of Condensation two or perhaps two thousand Bodies may be crouded into a space that is adequately fill'd by one of them apart And if this be not penetration of Dimensions I desire to be informed what is so and till then I shall leave it to any unprepossess'd Naturalist to judge whether an Hypothesis that needs suppose a thing so generally concluded to be impossible to Nature be probable or not and whether to tell us that the very same parcel of Air that is now without violence contain'd in half an Inch of space shall by and by fill two thousand times as much room and presently after shrink again into the two thousandth part of the space it newly possess'd be not to turn a Body into a Spirit and confounding their Notions attribute to the former the discriminating and least easily conceivable properties of the later And this Argument is I confess with me of that weight that this alone would keep me from admitting the Examiners Hypothesis Yet if any happier Contemplator shall prove so sharp-sighted as to devise and clearly propose a way of making the Rarefaction and Condensation hitherto argued against intelligible to me he is not like to find me obstinate Nor indeed is there sufficient cause why his succeeding in that attempt should make our Adversaries Hypothesis preferrable to ours since that would not prove it either necessary or so much as sufficient but only answer some of the Arguments that tend to prove ' its not intelligible And that we have other Arguments on our side than those that relate to Rarefaction and Condensation may appear partly by what has been discours'd already and partly by what we have now to subjoyn CHAP. IV. A Consideration pertinent to the present Controversie of what happens in trying the Torricellian and other Experiments at the tops and feet of Hills THere remain then yet a couple of Considerations to be oppos'd against the Examiners Hypothesis which though the past Discourse may make them
decimo modo producatur modo abbrevietur c. sicque argentum nunc demittat nunc elevet For since we have made it probable that the copious Fumes sometimes suddenly ascending into the Air and rolling up and down in it sometimes sensibly altering if good Authors may be credited the refraction of it and since some other causes mentioned in our eighteenth Experiment may alter the density and gravity of the Air that leans upon the restagnant Mercury I suppose the Reader will think it more intelligible and probable that alterations other than those produced by heat and cold may happen to the incumbent Atmosphere which freely communicates with the neighbouring Air and may thereby become sometimes more stufft and sometimes more destitute of adventitious Exhalations than that such changes should happen to a Funiculus included in Glass which according to our Author is impervious to the subtilest steams that are and concerning which he offers not so much as a Conjecture upon what other account it can happen to be sometimes contracted and sometimes stretch'd The 19 Experiment Upon this the Examiner has onely this short Animadversion In decimo nono ostendit aquam eodem modo per exhaustionem Recipientis descendere quo in praecedente descendere ostenderat argentum vivum cujus cum eadem sit ratio non est cur amplius ei insistamus In which words since he offers nothing new or peculiar to shew any incongruity in our Explication to our principles which agree very well with the new Phaenomena of the Experiment we are content to leave the Reader to judge of the Hypotheses themselves which of the two is the more probable either ours that onely requires that the Air in the Receiver should equally resist a Cylinder of Water and of Quicksilver when their weight is but the same though their altitudes be not or the Examiner's which exacts that according to what we formerly elsewhere noted Bodies of such differing nature and texture as Quicksilver and Water should need but just the same weight or strength to rarefie them into a Funiculus The 20 Experiment In his Examen of this Experiment our Author makes me infer from the Phaenomena he repeats that not onely the Air but the Water also has a Spring But though I suspect not that he does wilfully mistake my sense yet by what I write in this and the following Experiments the Reader may well enough perceive that I spoke but very doubtfully of a Spring in the water nay and that I did in the 154 page expresly teach That the intumescence of it might at least in great part proceed from that of the small parcels of Air which I thought to be usually harboured in the body of that liquor But whereas I ascribe the appearance of the Bubbles in the water to this that upon the exhaustion of some of the Air incumbent on the water the pressure of what remains is much debilitated whereby the little Particles of Air lurking in the Water are allowed to expand themselves into bubbles he rejects this Explication as manifestly false Nam sayes he si ita fieret deberent profecto hujusmodi bullulae non è fundo vasis sic ascendere uti tam in hoc quam in sequentibus experimentis in quibus de istis bullis agitur semper asseritur sed è superiore parte aquae ubi minus premuntur ut per se est manifestum But why he should be here so peremptory I confess I do not for all this Objection yet see For in the bottom of the next page he sayes he will not deny but that Aërial Particles latitant in the other parts of the water he had before spoken of the bottom of it may be extended into bubbles by his way of Rarefaction And that we particularly mentioned the rising of bubbles even from the bottom of the water was because that circumstance seem'd to deserve a peculiar note and not as he seems to imagine as if the bubbles did not also rise from the superior parts of the liquor since we did take notice of it about the middle of the 149 page And we often in this and the following Experiments observ'd that the ascending bubbles grew bigger the nearer they came to the top Which agrees more clearly with our Hypothesis wherein their conspicuous swelling as they ascend is attributed more to the lessening of the pressure of the incumbent Air than to the decrement of the weight of the incumbent water since when the surface of this liquor is lean'd upon by the Atmosphere the ascending bubbles scarce sensibly increase in Vessels no deeper than ours then with the Explication which the Examiner gives in these words Respondeo aquam per illant aëris exhaustionem non sponte sic ascendere sed sursum violenter trahi ac elevari à rare facto illo aëre sese contrahente Quemadmodum enim aqua aliqualem patitur compressionem ut experientiâ constat it a aliqualem quoque hic patitur distentionem Atque hinc clarè patet cur potius à fundo vasts quam à parte aquae superiore oriantur hujusmodi bullae Cum enim vehemens illa suctio conetur aquam à fundo phialae elevare nascitur ibidem subtilis quaedam materia quae in bullas conversa sic ascendit uti capite decimo quinto in quarto Experimento dictum est For whatever he may think it does not hence so clearly appear how the endeavour only of the Funiculus to draw up the Water from the bottom of the Vial to which that endeavour notwithstanding it remains contiguous should generate in some parts of the bottom of the Glass and not in others such a subtile matter as he tells us of And I suppose the Reader will as well as I wish he had more intelligibly declared how this strange generation of subtile matter comes to be effected And I presume it will likewise be expected that he also declare why both in our case and in the Torricellian Experiment the bubbles grow so much larger by being nearer the top of the liquor if as he rejects our Explication of this Circumstance the effect of the suction he speaks of be greater upon the lower part of the liquor than the upper to which alone nevertheless his Funiculus that is said so to draw the liquor is contiguous Our Author making no particular Objection against the 10 following Experiments we also shall pass them by and fall with him upon the consideration of the 31 Experiment The 31 Experiment Upon this our Author having recited our Conjecture as the cause why two very flat and smooth Marbles stick so closely together that by lifting up the uppermost you may take up also the lowermost approves my way of examining that Conjecture But whereas I say that the reason why though the Marbles were kept together by the pressure of the ambient Air yet they did not fall asunder in our exhausted Receiver no not though a weight of
the Bladder each of them being able to maintain but a very small Vortice to be by the subsiding Mercury in the Torricellian Experiment freed from the pressure of the Air and their motion continuing the same by reason that the Transcursion of their Vehicles is not at all or very little hindered either by the Glass or Bladder their parts having room to expand themselves will flie abroad to such Extensions as may perhaps make a Vortice 1000 times as big in bulk as what they were not able just before to exceed Hence the Particles of the Air being so gross as not easily to pervade the Pores of the Bladder must necessarily drive out the sides of the Bladder to its utmost extent and serve to fill the Receiver in the Magdeburgick Experiment Now whereas these Particles will by the same pressure of the Air be reduc'd to the same state they were in at first that is to be thronged into a very little room and thereby be able to maintain a very small Vortice the Air let in in the Torricellian Experiment reduces the Air in the Bladder to its former inconspicuousness as the admission of the Water in the Magdeburg Experiment does that Receiver full of rarefi'd Air into the bigness of a Hazel Nut. Now the Water in this last-mention'd Experiment enters with a great impetuosity because driven on with the whole pressure of the Atmosphere and resisted only by the small force of the so-far rarefi'd Air. As for the Author's Objection against this way of Rarefaction drawn from the Phaenomena of Gun-powder I shall endeavour to answer it by shewing them possibly explicable by a Cartesian Hypothesis For supposing those Terrestrial parts of the Gun-powder to be first at rest and afterwards agitated by the rapid motion of his first Element there will be sufficient difference of the former and later condition in respect of Extension and supposing the particular constitution of Gun-powder arising partly from the Specifick forms of the Particles of its ingredients Nitre Sulphure and Char-coal and partly from their proportionate commistion to be such as will readily yield to the motion of his Materia subtilis so soon as an ingress is admitted to it by the firing of any particular parcel of it the Expansion will be speedy enough So then let us suppose a Barrel of Gun-powder placed in some close room to some grains of which we will suppose some actual fire to be applied by which actual fire the Texture of the Powder being such those grains are suddenly fired that is many Millions of parts which before lay still and at rest are by the action of the burning Coals shatter'd as it were and put into a posture ready to be agitated by the rapid motion of the Materia subtilis into which posture they are no sooner put than agitated and whirled sufficiently by it whence follows a vast Expansion of that part of Gun-powder so fired For each of its parts being thus whirl'd and hurried round expel and beat off with great violence all the contiguous Particles so as that each Particle takes up now 1000 times as much Elbow-room if I may so speak as just before serv'd its turn and consequently those that are outermost take every one their way directly from the parcel or Corn they had lain quiet in being hurried away by the sudden Expansion of the Particles that lay next within them so that whatever grain or parcel of Gun-powder they chance to meet with before they have lost their motion they presently shiver and put into such a motion as makes them fit to receive the action of the Materia subtilis Which subtile Matter being every where present and nothing slow in performing its office immediately agitates those also like the former so that in a trice the Particles of the whole Barrel of Gun-powder are thus disordered and by the motion the Materia subtilis must needs be hurried away with so great an impetuosity on all sides as not only to break in pieces its slight wooden prison and remove the lighter Particles of the ambient Air but huge Beams nay vast accumulated Masses of the most compacted Structures of Stone and even shake the very Earth it self or whatever else stands in its way whose Texture is so close as not to give its Particles free passage through its Pores This understood I see not first what the Author 's three Arguments brought to prove his Objection signifie for there are no more Corpuscles in the room before the Gun-powder is fired than after nor is there any more matter or substance before the sides of the room by yielding give place for the external fluid Bodies to succeed and the only change is this that the Globuli secundi Elementi as he calls them are expell'd out of the room and the Materia primi Elementi succeeds in the place of it Nor do I see secondly what great reason he had for his grand Conclusion Haeo abundè demonstrant rarefactionem per hujusmodi corpuscula nullatenus posse explicari Having thus examined the Author's first Arguments that Rarefaction cannot be made out by any other way than his we shall find his other which he brings to establish his own Hypothesis much of the same kind As First that his way of Rarefaction implies no Contradiction For if the affirming a body to be really and totally in this place and at the same time to be really and wholly in another that is to be in this place and not to be in this place be not a Contradiction I know not what is Next that some learned School-men have thought so to which I answer more learned men have thought otherwise And lastly that there are very plain Examples of the like nature to be found in other things of which he only brings one viz. that of the Rota Aristotelica which upon examination we shall find to make as little to the purpose as any of the other An Explication of the Rota Aristotelica THe great Problem of the Rota Aristotelica by his explication of which he pretends not only to solve all the difficulties concerning Local motion quae Philosophorum ingenia bactenus valde exercuerunt but to give an instance for the confirmation of his unintelligible Hypothesis of Rarefaction wherein there is extensio seu correspondentia ejusdem rei ad locum nunc majorem nunc minorem we may upon examination find to be either a Paralogism or else nothing but what those Philosophers said whom he accounts gravel'd with it Of this Subject he begins in his 25th Chapter where after he has set down a description of it he makes an instance in a Cart-wheel Rem ante oculos ponit rota alicujus currus ejusque umbo seu lignum illudcrassum rotundum cui infiguntur radii siquidem dum progrediente curru ipsa rota circumduct a describit in subject a terra orbitam sibi aequalem umbo ille describit in subjecto aëre orbitam I suppose both
Vessel the Air thrust away by him that sucks cannot at all come to bear or press upon the water And yet whether the Pipe were inclin'd or erected the water did according to my expectation easily enough ascend upon suction to the top of the Pipe and ran over into my mouth I say easily enough because that though the Spring of the Air pent up in the Vial were able upon the decrease of the pressure of the outward Air occasion'd by my sucking to impell the water strongly enough into the Pipe yet when a pretty quantity of water had been so impell'd up the included Air gaining thereby more room to expand it self its spring was thereby so far weakned that the water ascended far less easily than in ordinary suction The other circumstances worth noting in this Experiment belong not to this place and what has been delivered may I hope suffice for the purpose 't is alledg'd for Onely one particular I shall here adde by way of confirmation of what I said touching the weakn'd Spring of the Air and it is this That partly to shew some who yet embrace the Opinion of the Schools that the ascension of the water in the Pipe did not proceed from any such tendency in the water it self to ascend for prevention of a Vacuum and partly for other reasons that concern not this place I did carefully take out the water by degrees till the lower end of the Pipe was but very little under the surface of the water though in the cavity of the Pipe the water as it usually will be in Pipes that are not wide was a pretty deal higher then suffering the Vessel to rest and sucking at the upper end of the Pipe the water as I foresaw it would be was impell'd up yet without reaching near the top till the surface of it was fallen a little below the bottom of the Pipe But then though I continu'd sucking no more water ascended into the Pipe but the Air passing through it towards my mouth did in its passage toss up the water that was already in the Pipe and turn it into bubbles of a strong bigness when the cavity of the Pipe would permit it which broke not without noise one after another and thus the ascending Air for a pretty while kept the water in the Pipe from falling back to that in the Vial. But when I remov'd my mouth the Spring of the Air remaining in the Cavity of the Vial being debilitated by the recess of the Air I had as men are wont to speak suck'd out it was not able to resist the pressure of the outward Air and accordingly the water in the Pipe was not onely depress'd into the Vial but the outward Air forc'd its way in many bubbles and not without some noise through the water contiguous to the bottom of the Pipe till the pressure of the included Air and that of the Atmosphere were reduc'd to an equality But in the same 25. page our Author tells us that the Society he writes against would have the cause of Filtration and that of the passage of water through Siphons to be the same To which he annexes this peremptory passage Id vero impossibile est Nam in Siphone nisi ambo crura aquâ impleantur aqua è pelvi non ascendet Ascensionis causa in pannum est motus ille terrearum atomorum quae aquae contiguae sunt motus inquam circularis simplex aëri in quo moventur communicatus quae atomi aquam ferientes in materiam laneam incutiunt incussae autem magis magisque madefaciunt donec madida tota sit Cum vero madida tota sit c. Thus far he but the passage in my Epistle upon which he seems to have grounded his Opposition is but this wherewith I begin my 35. Experiment Some learned Mathematicians I meant the industrious Schottus and some Cartesians have of late ingeniously endeavoured to reduce Filtres to Siphons but still the cause of the ascension of water and other liquor both in Siphons and in Filtration needing for ought we have yet found a clearer discovery and explication we were desirous to try c. So that neither did I ascribe this reduction of Filtres to Siphons to a Society which was not then in being nor perhaps so much as design'd nor did I adopt it my self but express'd a desire to have it further examin'd But as for the cause of Filtration it self I may take a fitter opportunity to discourse of it in the mean time I doubt whether the reason here assign'd by Mr. Hobbs will not seem as well precarious as the motus circularis simplex of earthly Atoms whereon it is grounded Nor does his Explication render a reason why Quicksilver will not ascend the 14. part as high in the Filtre though in part immers'd into it as water nay will not reach so high where 't is contiguous to the Filtre as where 't is not nor why it should begin to ascend since for ought he shews to the contrary the pressure of the Air even in the sense he takes the Air ought to be the same on that part of the Surface of the Liquor which is contiguous to the Filtre and on any other part of the same Surface To which I shall onely adde that as resolutely as Mr. Hobbs sayes 't is impossible for the water to ascend out of the Vessel into a Siphon unless both the legs be fill'd with that Liquor he would probably have spoken more warily and distinguish'd betwixt Siphons if he had been pleased to take notice of what I relate in the-forementioned 35. Experiment of a small Glass-Siphon I devis'd whereof when the shorter leg was but dipp'd in water the Liquor did presently as it were of it self run down the longer leg Which Experiment besides other considerations may induce us to suspect that the nature of Siphons and of Filtration may not yet be so throughly understood as not to deserve a further enquiry But to draw at length towards a Conclusion of our troublesome Examen it remains onely that I take some notice of the general Corollary that Mr. Hobbs is pleased to deduce from his whole Discourse of the Experiments exhibited in our Engine A. Fateris ergo says he nihil hactenus à Collegis tuis promotam esse scientiam causarum naturalium nisi quod unus eorum machinam invenerit qua motus excitari aeris possit talis ut partes sphaerae simul undiquaque tendant ad centrum ut Hypotheses Hobbianae ante quidem satis probabiles hinc reddantur probabiliores B. Nec fateri pudet nam Est aliquid prodire tenus si non datur ultra A. Quid tenus Quorsum autem tantus apparatus sumptus machinarum factu difficilium ut eatenus tantum prodiretis quantum ante prodierat Hobbius cur non inde potius incepistis ubi ille desiit cur principiis ab eo positis non estis usi Cumque Aristoteles recte dixisset
very passage and within a very few lines he has recourse in this matter to God's Omnipotence I see not why an infinite division cannot be as well conceived as an infinite divisibility since sure an Omnipotent Agent is able to do what is possible to be done and why else should a body be called infinitely divisible Besides when Mr. Hobbs has recourse to what God can do whose Omnipotence we have both great reason to acknowledge it imports not to the Controversie about Fluidity to determine what the Almighty Creator can do but what he actually has done And lastly whereas my Adversary requires to have the magnitude defined which a part of a falling Wall ought to have to deserve the name of fluid first he should have clearly proved that Fluidity belongs to any one single part of matter how minute soever and not rather to an aggregate of Particles And next I say those Corpuscles that compose a fluid body may be of several sizes as those of Water Oyl and Quicksilver provided they be little enough to be put into the agitation requisite to give the aggregate they make up the qualities that are wont to denominate bodies fluid and 't is no more requisite for me to define precisely the magnitudes of the parts of a fluid body than for Mr. Hobbs in his Definition above-recited to define which he will not easily do what precise degree of endeavour must be signified by that very weak endeavour by which if the parts of a body can be separated from one another he thinks fit to call them fluid But though I thought it not amiss to make these Animadversions upon Mr. Hobbs's Ratiocination yet as to the Opinion it self for whose sake he speaks so severely and so despairingly of our Society if it be considered as I propos'd it he shews me as yet no cause at all to renounce it For that which I taught is this That if a solid body be reduc'd into parts minute enough those solid Corpuscles whilst they are put into a convenient motion may become parts of a fluid body And against this Mr. Hobbs's indignation seems stronger than his Argument For that which he objects being as we have lately seen that at this rate all bodies must be fluid 't is evident by what I have already argued that he infers this Absurdity not from my Opinion but his own mistake of it nor did I content my self with the proofless proposal of my Conjecture but I delivered in several parts of the often mention'd History particular Experiments to evince what I taught As that a consistent coagulum of pure spirits of Urine and Wine may by bare digestion be turned into a permanent liquor and that the fluid body of Quicksilver may without any sensible addition be turned into a permanent dry Powder and may again in a trice by bare heat be turned into a lastingly fluid body Whereto I added other Experiments which together with these Mr. Hobbs would possibly have thought fit to answer if he had found it easie for him to do so After this passage extant in Mr. Hobbs's fifth page that I have all this while been examining I remember nothing in his Dialogue that requires to be insisted on about Fluidity and Firmness till we come to the 29. page where having asked what cause the Academians assign of Hardness 't is answered that some of them assign three to which Mr. Hobbs so far agrees as to say Quin corpuscula qualia sunt atomi quas supponit Lucretius atque etiam Hobbius jam ante dur a facile possint ab aliqua dict arum causaram compingi it a ut totum ex illis factum durum fiat dubitandum non est But then he would have us assign the cause of that he calls durum primum But after some discourse wherein he is pleased to approve an Objection of mine against some learned men that ascribe all Cohesion of bodies to a certain Glue he answers himself the Objection he frames against my Doctrine about Hardness and thereby allowed me to proceed to what he further presses in these words Si dura ex primis duris fieri dicant quare non fluida fieri putant ex primis fluidis An creari fluida maxima potuere ut aether minima non potuere Qui Corpusculum durum aut fluidum primus fecit potuit si libuisset illud fecisse tum majus tum minus quocunque corpore dato Quod si fluidum fiat ex non fluidis ut vos dicitis durum ex duris tantum nonne sequitur ex fluidis primis neque fluidum fieri neque durum But against this passage I have divers things to represent For first not now to mention that it may be questioned with what propriety one part of matter more than another may be called primum durum he should have told us what he means by his prima fluida and how he proves that there are any such which since he has not done 't will be at least as hard for a considering man to acquiesce in his Question as to answer it For my part I know no fluid body upon whose account as of an Ingredient all others are fluid And I think 't will be hard for Mr. Hobbs to shew that Water Quicksilver and purely-rectifi'd Chymical Oyles to name now no other liquors do consist of such fluida prima as he teaches whereto they owe all their Fluidity And 't is plain by several Experiments delivered in our History and even by the obvious changes of Water and Ice into one another that 't is the motion rest and the texture of the Corpuscles which compose a Body that make it firm or fluid As for what Mr. Hobbs demands whether the smallest Fluids imaginable could not as well have been created as the AEther it proves nothing against me the Question not being what might have been made but what is so And he should have answered the Arguments I alledge to make it improbable that a fluid body is as he would perswade us in his Book De Corpore alwayes divisible into bodies equally fluid as Quantity into Quantities 'T is true he there tells us that though many others do not He understands by Fluidity that which is made such by Nature equally in every part of the fluid body in such manner as water seems fluid and to divide it self into parts perpetually fluid But whether others will take this for a clear Notion of Fluidity I think may well be doubted and he should not barely say but prove which I think he will find hard to do that the Corpuscles of water divide themselves so as he teaches since we see that not onely they cannot penetrate Glass but are unable to be driven in at the Pores of more open bodies which other liquors easily pierce into And lastly as to Mr. Hobbs's Question Quod si fluidum fiat c. 't is easie to foresee what according to my Doctrine
c. Here our men are at a stand How will you expedite this difficulty A. I have don 't already For the Air being beaten back by the retraction of the Sucker and finding no place in the world which we suppose to be full where it might dispose it self besides that which by driving out other bodies from their places it may make for it self is by perpetual pulsion at length forced in the Cylinder with so great swiftness between the concave surface of the Cylinder and the convex surface of the Sucker as may answer that store of power which you found necessary to the drawing back of the Sucker Now the Air with what swiftness it enters retains the same within and then distends every way the sides of the Brass Cylinder which is of it self Elastical Therefore the Air in the Cylinder being vehemently moved endeavours or thrusts against all parts of the concave surface of the Cylinder but in vain untill the Sucker is drawn back But as soon as the Sucker having slipt the hand ceases to make its impulse upon the Air that Air which was before driven in by reason of its endeavour against every point of the internal superficies of the Cylinder and of the Elastical force of the Air will insinuate it self between the same surfaces with the same swiftness as that by which it was impell'd that is with that velocity which answers the strength of the impulsion If therefore so great a power of Weight be hung upon the Sucker as may answer the power of the hands by which it was impulss'd the swiftness with which the same Air goes out of the Cylinder finding no place in the world which is full where to dispose it self will again impell the Sucker to the top of the Cylinder for the same reason that the Sucker a little before made an impulse upon the Air. p. 44. In vas c. B. We poured water into an open Vessel we placed in the water a long streight slender Tube and we observed that the water did ascend from the Vessel underneath into the erected Tube A. No wonder For the small Particles that are interspers'd in the Air near the Water did by their motion beat upon the surface of the Water so that the Water must of necessity ascend into the Pipe and that sensibly into a Pipe that was so exceeding slender p. 45. Siquis c. If any one after the frequently-repeated impulse and retraction of the Sucker endeavour to draw out the Stopple of the upper Orifice of the Receiver he shall find it gravitates very much as if a weight of many pounds hung upon it Whence comes this A. From a strong circular endeavour of the Air within the Receiver made by the violent ingress of the Air between the convex surface of the Sucker and the concave of the Cylinder procured by the repeated impulse and revulsion of the Sucker which you improperly call the Exsuction of the Air. For by reason of the fullness of Nature the Stopple cannot be drawn out but the Air that is in the Receiver contiguous to the Stopple must be drawn out too which Air if it were settled and at rest the Stopple would easily be drawn out but whiles that doesmost swiftly circulate it comes out very hardly that is it seems to be very heavy B. Very likely For as soon as fresh Air is by degrees let into the Receiver it likewise by degrees loses this seeming gravity p. 47. Vidimus c. We saw also water being let down into the Receiver after some returns of the motion of the Sucker to bubble so as if it had boiled over a fire A. This likewise happens as we spake by reason of the swiftness of the circulating Air unless perhaps you find the water hot too whiles it bubbles For if we were sure it was hot we must find out some other cause of the Phaenomenon B. We are certain it is not sensibly hot A. In what therefore can the greater or lesser motion of the Atmosphere promote such a motion as this B. I suppose they do not attribute this motion to the Atmosphere p. 49. A. It is manifest from this Experiment that the Receiver is not made empty by this exsuction of Air as you call it For the water could not be moved but by some contiguous mover that was it self in motion Therefore this Phaenomenon seems to contain no weak demonstration of my Hypothesis p. 50. Besides tell me could you see the water bubbling in that manner B. What else A. Do not your Associates grant that Vision is made by a continued action from the object unto the eye Do they not also think action to be motion and all motion to be of some body How therefore could the motion be derived from the object the water unto your eyes through a Vacuum that is somewhat that is not a body B. Our friends do not affirm the Recipient to be so empty that no Air at all is left A. No matter whether the Receiver be wholly or for the greater part empty for which ever you suppose the derivation of the motion from the object to the eye will be intercepted B. It may be so I can't tell what to answer p. 51. Credin ' tu c. Do you think these Animals were therefore so quickly killed because they wanted Air How then do they who make a trade of Diving live under water of whom there be some who being accustomed from their childhood have wanted Air a whole hour No. Thatmost vehement motion by which Bladders shut therein are distended and broken kills these Animals shut up in the Receiver Ibid. Ego contra c. I on the contrary think that neither the Air can be suck'd out nor that the Animal would so soon dye if it were suck'd out The action indeed to which this death is a consequent may seem either a certain suction and so that the Animal is kill'd by the exsuction of the included Air its Respiration being taken away or a compulsion of the Air from all parts towards the Centre of the spherical Glass in which the Animal is inclosed and so may be seen to dye stifled by the tenacity of the compress'd Air as it were with Water the Air more tenacious than usual being drawn into the inwards of the Lungs and there between the Pulmonary Artery and Vein stopping the course of the blood p. 53. Placet c. Your Hypothesis pleases me better than that of the Spring of the Air For from its truth depends the truth of a Vacuum or a Plenum but from the truth of that nothing follows on either part of the Question The make of the Air sayes he is like that of comprest wooll Well wooll is made of hairs or threds Right but of what figure if of a Parallelopipedon there can be no compression of parts if not of a Parallelopipedon there will be betwixt the hairs certain spaces left which if they be empty they suppose
some place empty to prove that a Vacuum is possible if full they say that is full which they suppose to be empty p. 56. Fuere c. There were some of them that said there remained in those coals though they seem'd extinguish'd some fiery Particles which being blow'd up by the Air upon its admission did re-kindle the rest of the mass Ibid. Nae c. In good faith they seem not so much as to have considered what they should speak as to have taken it up at all adventures Do you believe that in a kindled coal there is any part which is not a coal but fire or in a red-hot Iron there is any part that is not Iron but Fire A great City may be set on fire by one spark Now if the body of fire be different from the thing fired there can be no more parts of fire in the whole Town on fire than that one spark We see bodies of divers kinds may be set on fire by the light of the Sun as well by the Refraction as the Reflexion that is made in Burning-glasses And yet I do not believe that there is any man thinks that Particles of fire darted from the Sun can pass through the substance of a crystal Globe And in the Air between the Sun and the Globe there is no fire p. 58. When is it that we may truly say of a man that he is dead or which is the same hath expired his Soul For it has been known that some men who have been taken for dead being brought out the next day revived A. It is hard to determine the point of time in which the soul is separated from the body Proceed therefore to other Experiments p. 59. Si acus c. If a Needle excited by a Loadstone hang freely within the Receiver it will nevertheless follow the motion of the Iron which is drawn about without the Receiver So objects put within will be seen by those that are without and sounds made within will be heard without all these as well after as before the exsuction of the Air except that the sounds are somewhat more weakly heard after than before B. These are most manifest signs that the Receiver is alwayes full and that the Air cannot thence be suck'd out That the sounds thence are more weak to ones hearing is a sign of the consistence of the Air for the consistence of the Air is diametrically opposite from its motion p. 61. Quia nihil c. Because there was nothing there that the weight of the Atmosphere should do no more strong or evident Argument could be made against a Vacuum than this Experiment For if of two coherent Marbles either of them should be thrust forward that way that their surfaces lye contiguous they would easily be sever'd the neighbouring Air successively flowing into the deserted place But so to pull them asunder that at one time they should lose their whole contact is impossible the world being full For then either motion must be made from one term to another in an instant or two bodies at the same time must be in the same place to say either of which is absurd p. 62. Confitentur c. They themselves and all others confess that all Ponderation is an endeavour every way by right lines unto the Centre of the Earth and so that it is made not by the figure of a Cylinder or Column but by a Pyramide whose top is the Centre of the Earth and whose Basis is part of the surface of the Atmosphere Ibid. Conatus c. Therefore the endeavour of all the points that ponderate will be propagated to the surface of the upper Marble before it can be propagated further suppose to the Earth p. 64. Has c. These Scales he puts one upon another and draws out the Air and then are they kept so comprest and united by the gravity of the external Air that six strong men cannot pull them asunder But if at length by the use of utmost endeavour they are pluckt in sunder they make a noise equal to the report of a Musquet but as soon as ever by the Stop-cock open'd there is the least entrance given to the Air they are severed of their own accord p. 65. Sed vis c. But can the Spring which they say is in the Air confer nothing to the holding up the Marble Nothing at all For there is no endeavour of the Air to the Centre of the Earth more than to any other point in the Universe For seeing that heavy things tend from the circumference of the Atmosphere unto the Centre of the Earth and thence again to the circumference of the Atmosphere by the same reflected lines the endeavour upwards will be equal to the endeavour downwards and so destroying one another they will endeavour neither way p. 66. Non potest ergo pars BC c. Therefore the part BC that is a part of the Atmosphere placed any where within the whole cannot by reason of its greatness descend although it be heavy and therefore it cannot press or gravitate Ibid. Si possibile c. If I should deny it possible that by the art of man two furfaces of two bodies could be made so accurately fit that they should touch in all points so that there could no creable Corpuscle pass between them I do not see how they could defend their own Hypothesis or disprove our Negative assertion Ibid. Vtraque c. Both these Fancies as well that of the Weight as of the Spring or Antitupy of the Air are Dreams But if it be granted that there is a kind of Recoyling in those small hairs or slender Corpuscles of which the Air consists one may enquire whence it is that those crooked bodies settled and at quiet in that posture came to be moved into a streightness They ought if they will be esteemed Natural Phylosophers to assign some possible cause of this p. 67. Cur non c. Why cannot the water which when it was injected did compress the particles of Air be again cast out by the same particles explicating themselves A. Because when explicated they require no greater place than when comprest As in a vessel full of water wherein are many Eeles the same proportion of place receives them whether they are folded round or at length Therefore they cannot drive up the water by their Spring which is nothing else but the motion of bodies explicating themselves B. The comparison of Air to Eeles in water I suppose will be well received by our Academians p. 68. Vides c. You see how foolish a thing it is to bring for the explication of such effects Metaphorical words as the shunning of a Vacuum the ahhorrence of Nature c. which heretofore the Schools used to defend their reputation Ibid. In the Gardeners Watering-pots therefore is the water suspended because that which issues out at so small a hole is so little that it cannot diffuse it self to