Spherical Capacity by means of a Weight at pleasure hung at F close then the folds of the Bladder and bind it very strait round the Neck BC at E taking care when you bind it to pour in Water till it runs over so to be secure that no air is included which might any way alter or spoil the due and right Operation of the Instrument Every thing being performed after this manner at the foot of a Tower fasten to the Ball at G a string let down from the top of the Tower and having observed the Degrees whereat the Water stands let it be drawn up when again observing it will be found Deprest some Degrees lower as to H which will be more or less according to the present State of the air and the greater or lesser height of the Tower This also they say happens for as much as the Bladder EF is encompassed with the air of the higher Region and so not sufficiently armed externally to resist the Force made on it by the air of the lower Region which is included in the space GD in Dilating it self whence it must necessarily yield to enlarge its internal Capacity which the small Bulk of Water DH sinks down to fill out Tab. 7. p 39 The Fourth Instrument CAuse a Glass Ball to be made A with its Neck BC like the Third Instrument onely it must have an open Beak drawn very slender D round the Mouth of the Neck C bind the Bladder EF very close this Bladder is to have in its lower Ligature F a small thread of Glass or Brass-wire which passing through the Bladder is to enter into the Neck of the Ball BC and so point at the Degrees it is minutely divided into let this Instrument be carried to the foot of the Tower seal it as the other at D and take notice of the Degree pointed at by the End or Dart G raise it then to the top of the Tower and you will find the Dart higher than before by some Degrees To give the reason of this Effect they consider that the Vessel is filled with air of the same Temperament with that below which as it finds one part of the Vessel less Solid than the Glass yielding and easie to be distended such as is the Bladder EF so it no sooner perceives it self relaxed from the Prison of the surrounding air by being raised to a higher place but it immediately endeavours to enlarge it self and be at liberty which it Effects by swelling the Bladder a little more Now whilst this by being so puffed up comes nearer to a Spherical Figure the transverse Diameter of the Ellipsis EF is shortned as the bottom F is gradually raised when also the Index FG fastned thereunto by obeying its Motion rises higher in the Neck BC and so comes to point at a higher Degree than G. Various Experiments made in Vacuo FRom the Series of the afore-mentioned Experiments Torricelli's thought touching the Airs Pressure upon all Inferior Bodies seems fully confirmed And tho it may be a daring undertaking and full of hazard to determine of the Causes where Geometry gives no Illumination yet this boldness is never more excusable nor the danger more like to be avoided than when our Understanding onely by a Path of many and all agreeing Experiments makes toward the attainment of its desire which tho it may sometimes fail off yet it is satisfied in approaching as near as may be towards it Since then it appears from the Effects already mentioned that we have gained some reasonable probability of such a Pressure it was judged not altogether a fruitless labour to proceed to make divers Experiments in Vacuo and observe whether the manner of their operation would succeed contrary or any way different to what they appear when environed on every side with the free Air. Experiments To know whether small drops of Liquid Bodies being freed from the Airs Pressure encompassing them lose the Spherical Figure they naturally are off SOme have Attributed to the Pressure of the air that generally known Observation of the drops of Mercury Tab. 8. p. 41. or any other Fluid which spurted or raining through the air or let fall upon any dry or dusty body always are nearly of a Globular Figure wherefore they were willing to try it in Vacuo imagining there might then happen some notable Variation But Experience it self shewed That the Effect proceeded from some other cause than the airs Pressure for having made the Vacuum in the Vessel AB the cavity A being quite void by turning the Stop-cock there was let fall some drops of Water or Mercury out of the Ball C upon some Colewort-leaves included in the Ball A which had some drops of Dew hanging on them with which they were gathered these Drops that were admitted contracted themselves as round as if they had been upon a growing Plant. So when the air in the Vessel A was condensed or rarefied by means of a Syringe CB the Drops of Water or Mercury sprinkled upon the bottom of the Vessel were not altered from their usual shape An Experiment Shewing the Effect of Heat and Cold applyed Externally to the void space BInd the Bladder ABC under the Ball D make the Vacuum therein turn the Bladder upwards to be tyed there likewise then with a Cane of Glass or any thing else that will not alter or bend take the exact height of the Mercurial Cilinder HG from the Stagnant Mercury EF after this fill the Bladder with hot water and soon after measuring you will find the Cilinder a little depress'd below the former height This Observation made throw out the hot water let it stand till it returns to the former height H and then fill the Bladder with cold water mixt with beaten Ice and Salt and in a little while measuring as before you will observe the Cilinder notably raised Nor will we omit that the Hot Water made use of in this Experiment raised a Thermometer of 50 deg to 48° and with the same Heat shortned the Mercurial Cilinder one 146 th part of the whole Height And that the Cold Water increased to one 50 th part when in the same Water the Thermometer came to 11 deg ◠2. If then a little air be admitted into the Ball D this because it becomes very thin by reason of the Dilatation it has in the void space quickly imbibes Heat or Cold and by its Rarefaction or Condensation causes that the Alterations in the Rise or Fall of the Mercury are much more sensible and swift An Experiment To manifest whether the Air be that which serving as a Foile to the lower Superficies of a Lens of Glass reflects that second Image inverted more dimly and faintly which we see of a Flame or any other Object Visible there as Kepler thinks it is ON the Mouth of the Glass Vessel AC we cemented with hard cement a Glass Lens AB this Mouth had its Lips turned a little
of making the Experiment under Water which perhaps might detect something to us so we took the bladder out of the Fish alive and well tying it in a Net fastened a convenient weight and sunk it in water and then made the vacuum when we might see many small bubbles of air issue from the slender part thereof where 't is probable the Natural Meatus is which transmits it when the Vessel was opened the air shrunk it like the other Lastly willing to see what way the air takes from the bladder to get out of the Fishes Body whether by the Gills or Mouth we covered a Roach with the same Net that by affixing a Weight it might be kept under water the vacuum being made we saw a great deal of air come out of his Mouth in large bubbles as before from the submersed bladder Here should have been the End of these Experiments but while these Sheets were in the Press one of our Academy having thought of a way to facilitate very much the management of our Vessel to make the vacuum we will not omit to set it down here and the rather because we found it indeed very convenient The Invention consists in joyning to the Cane BE Tab. 10. Fig. 1. the Retum BFG designed in the Figure by the Prick'd Line for putting as usual the Mercury in at the Mouth AC when it comes up to G in the Return we tye it down close and fill it up to AC where being closed after the usual manner it is sufficient to open the Mouth G and without any immersion all the Mercury above 28 6 10 Inches taken from G towards E runs out and Note that the Ball FG serves to keep in the Mercury in the fluctuating Motions it makes in the Two Branches of the Cane before it rests caused by the impetus of its fall This is all at present touching the Natural Pressure of the Air and its Various Effects EXPERIMENTS OF Artificial Freezing AMong the rest of the stupendious Works of Nature that admirable Power has been always much regarded whereby she binds the slippery Waves changing their fleeting Inconstancy into Solidity and hardness This Effect tho daily before our Eyes in comparison of others more secret and rare yet has continually afforded Ample Subjects of Curious Speculation to the Mind of Man for whereas Fire when disingaged in swiftly winged sparks by insinuating it self through the close Pores of Flinty and Metalline Bodies opens melts and reduces them to a perfect Fluid so Cold on the contrary a much stranger thing stops and consolidates the most Fluid Liquors changing them into downy Snow and glassie Ice which upon the least Ray or warm breath break Prison and steal away in their first fluidity again And which is yet more amazing so violent a force of Cold in Freezing is observed penetrating not onely Glass but even the secret Pores of Metals As in the Subterranean Caverns and deep Mines the Raging Flames impetuously divide and in fury open all those dark Passages so Cold in the Act of Freezing cracks shut Vessels of thick and strong Glass stretches distends and at last tears those of pure Gold and bursts asunder those of Cast Brass and of such thickness as to break them by dead weight would require perchance nay assuredly some Thousand weight upon this strange Phenomenon of Freezing observable in water more than any other Fluid Some have thought that where the Cold operates in its proper Laboratory with fit materials it reduces the pure Water to such a temperament that it turns it into even the hardest Rock-Cristal and Gems of various Colours according to the different Tinctures received from the neighbouring Mineral steams nay even into the Invincible hardness of the Diamond And Plato was of this Opinion That Diamonds were Generated of the remains of those Waters whence in the secret Caverns of the Earth he thought Gold was produced and therefore a Diamond is called the off-spring of Gold by that Divine Philosopher in Timaeo But to return to the Causes of Freezing The ingenious in all times have had various Sentiments thereof whether it does indeed come from any real and proper body of cold which in the Schools they call Positive that as Light and Heat are Originally in the Sun is either in the Air or Water or Ice it self or any other part of the Vniverse as its proper place and Residence where it has its Repository and Treasury in which sence the Words of the Divine Oracle in Sacred Writ may be taken Hast thou entered into the Treasures of the Snow or hast thou seen the Treasures of the Hail Or whether Cold is nothing else but a Total Privation or driving away of Heat Touching this and other curious Observations of the Artifice used by Nature in Freezing whether she Atchieves her End by Contracting or Rarefying the Fluid whether the Change proceeds slowly or instantaneously c. we were induced to try several Experiments of Artificial Freezing made by the outward application of Ice and Salt fully perswaded that the operation does not at all vary from the procedure of Nature when by the pure and simple cold of the Air she Congeals Water What hitherto we have had the good luck to observe upon so vast and boundless a Subject capable of so great and endless Observations will be offered to you in the following Experiments Experiments To know if Water dilates it self in Freezing IT was the thoughts of Galileo That Ice was rather Water Rarefied than condensed because says he Condensation consists in Diminution of Bulk but increase of weight and Rarefaction in the increase of Lightness and Bulk too but water in freezing gains in Bulk and Ice is lighter than Water since it swims thereon c. This being supposed which Experience will sufficiently prove we were curious to see what water would do when confined in a Vessel where it had not the least room to dilate yet on all sides being encompassed with Ice to freeze it since we still observed agreeable to Galileo that water as well frozen into great Mountains of Ice as in the smallest pieces and of what Figure soever continually swims upon the Surface of other Water a certain proof that in the act of freezing the increasing of the Bulk considered it grows lighter whether it be by the interposition of small and insensible vacuities or interspersion of Minute Particles of air or the like matter after the manner of little blebs in Cristal and Glass for such they appear to the Eye through the body of the Ice when held up against the Light in some places thicker in others fewer and if the Ice be broke into small pieces under Water they rise up through the Water in great Numbers The First Experiment TAking a Vessel of thin Silver Plate with Two Covers to screw on such as we use to cool our Sherbet and other Drinks in Summer we fill'd it with fair water cooled
being crammed with little Balls of Solid Crystal were dissected by us in a few hours and opening their Ventricles in the Sun they seemed to us covered all over with a glittering Coat which examining with a Microscope we found it to be onely strewed over with exquisitely fine and impalpable powder of Crystal In others likewise crammed with hollow Bubbles of Crystal-Glass with a small hole in them we were amazed to find of the said Bubbles some already broken and powdered others onely crack'd and filled with a Whitish Substance like curdled Milk got in at the small hole and we also observed that those were better powdered than the others which had in the Maws with them a greater Quantity of small Stones And 't is less strange that they break and grind to pieces Corke and any hard Woods as Cypress and Beech and rub to Powder Olive-stones the hardest Pine-Apple Kernels and Pistaches put down their Mouths with the Husk on Pistol bullets in Twenty four Hours we have found much Battered and several little hollow square Boxes of Tin were observed to be some scratched and battered others tore open from one side to the other FINIS A TABLE OF The Principal Matters Contained in this Work A. ACademie del Cimento intends not to dispute of the Experiments Page 16 and 33. Air diminishes the force of all Bodies that cut it p. 146. perhaps in continual motion p 14. Presses together those Bladders that seemed full in Vacuo p. 18. Dilates and Expands it self in Vacuo ib. What remains in the void space above the Mercury presses not thereon p. 23. When it is Dilated beyond the state of its Natural Compressure p. 23. The measure thereof ib. Proportion between Air Natural and Air Expanded as 1 to 174. p 24 When most rarifyed unfit for Respiration of Animals p. 61. Of Altering the Colours of several Fluids p. 133. Amber in Vacuo loses its Electric Quality p. 43. Which sort richest in that Quality p 128. Attracts any thing but flâ—me p. 129. Rubb'd upon smooth Bodies Attracts not p. 130 Acts no more upon the attracted Body than it suffers thereby p. 130. Acts upon all Liquids ib. By what Liquors hindred from attracting p. 131. Antiperistasis Experiments against it p. 151. Attraction by what hindred in Amber by the same also in other Bodies of Electic Virtue p. 129. A peculiar Effect observed in the Attraction of Rose and Table Diamonds p. 13â— B. Balls of Glass burst with great Violence p. 150 A Barbel taken alive out of a Vacuum and kept in a Pond with some observables thereon p. 66 Birds soon killed in Vacuo and why p. 63 Bladders of Fish in Vacuo p. 66 Blâ—bs in Ice what p. 71 Brass to what thickness burst by Frost p. 77 Bullets not wrapt about fly farther with the same charge of powder than those that are p. 144 C. Canes of Glass how made to be stop'd with a Finger easily p. 26 Cement to joyn together the mouths of Vessels p. 17 Change of Air produces an alteration in Experiments p. 1 Changing of Colours in several Liquors p. 133 Circles in Water move swifter as the force that makes them is greater p. 139 Clocks uncapable to shew the Minute divisions of time p. 10. Why made use of in the Experiments of Freezing p. 82 Cold whether reflected by Glasses as Heat and Light are p. 103 Cold and Heat Clouds and Mists encrease and lessen the weight of the Air p. 15. supposed by some the parent of Rock Cristal and Gems p. 70. Whether any thing Positive or onely a Privation of heat p. 70. Once imprest upon a Fluid shoots it into Ice after 't is taken out of the freezing mixture p. 80. * whether caused by an Intrusion of frigorifique Atoms p. 152 D. Dew upon the outsides of Glasses frozen p. 102 Diamonds how generated according to Plato p. 70 Table Diamonds less Electric than Roses p. 131 Digestion of some Animals how performed Several Experiments thereon p. 160 Drops of Liquors thought to be Spherical from the Airs Pressure p. 40 Disproved p. 41 E. A Cold Ebullition caused by a mixture of Sal Armoniac and Oyl of Vitriol p. 153 A strange Effect of Heat in subliming Liquors included in Vessels p. 150 Electricity what substances impregnated therewith p. 128 Experiments requiring an Exact measure of Time p. 11 the best way of Examining Nature p. 1â—4 Extrusion or pulsion of Bodies a thing known to the Ancients more especially evident from a Passage in Plato's Timeus p. 118 F. Fire and its Effluvia what Effect they have in Vacuo p. 46 Fishes kept a while in Vacuo dye disgorging some Air. p. 65 Flame diverts and abates the Virtue of Amber p. 129 Fluids aptest to move and why p. 13 Why different Fluids are raised to different heights by the incumbent Air p. 14. Fluids added to the Airs Pressure raise the Mercury above the usuâ— height p. 30 Force of Rarifaction in freezing Water how great p. 77 How thought reducible to dead Weight ib. Freezing how caused in Fluids p. 95 Artificial with its procedure and accidents p. 77 * Made in a very short time almost instantaneous p. 80 * What order it observes in divers Fluids p. 83 Tables of Freezings p. ib. The Explâ—catian of the Terms used in the Tables of Freezings p. 81 Those of the same Fluids Repeated still uniform p. 84 Natural Freezing with the procedure thereof p. 95 Diversity of the Figure of the Vessels causes some little diversity in the Freezings p. 96 Whether caused by the intrusion of Frigorifick Atoms p. 70 Froth in Vacuo expands it self p. 59 A sort of Funnel to fill Vessels with narrow Necks p. 3 G. Gems Transparent all Electric more or less p. 128 Glass Vessels enlarged by hot Water and lessened by cold p. 104 Stretch'd by the weight of the contained Mercury p. 113 Impenetrable by Odours and Moisture p. 155 Glass Balls burst with great violence p. 150 Glass and Cristal Electrical p. 128 Gold Vessels distended by the force of freezing p. 76 Gun-Powder fired with a Burning glass p. 144 H. Height of Liquors set in hot Water or Ice altered by the dilating or contracting of the Vessel p. 105 Horizontal discharge of Cannon dispatch the Ball in about the same time that it falls from the Mouth of the Piece perpendicular to the ground p. 143 Humidity of Winds how distinguish'd p. 9 I. Ice according to Galileo is Water Rarifyed not Condensed p. 71 Has not its full hardness at first p. 95 Produced by Art tenderer than the Natural ib. Made in Vacuo wherein different from that made in Air p. 98 How to find that difference ib. Sends forth a moist Exhalation p. 102 Sprinkled with Salt destroys the Vertue of Amber p. 129 The cause thereof proposed by some p. 130 Instruments shewing the heat and cold of the Air p. 2 Shewing the moisture of the Air p. 8 To measure time p. 10 Shewing the different
wonderfully intend the freezing and if besides the strong-Water you add salt it will prove most powerful nay sugar produces such an Effect but not much in comparison of common Salt Nitre and Sal-armoniac which we found much more successful in the operation of freezing than all the Rest The Sixth Experiment Touching what Metal preserves Ice best PUtting Ice in Vessels of several different Metals to observe which kept it the longest unthaw'd yet of this we could obtain nothing certain tho we may say at large from a very great number of Experiments which we made that it was preserved best of all in Lead very well in Tin but a short time in Copper and Iron less in Gold and yet a lesser time in Silver nevertheless at sometimes this order was changed it melting sooner in Tin and Lead than in Silver and Gold wherefore as we hinted this Experiment is not to be much confided in but proposed here rather to excite others to attempt it by some more secure way than to shew any certainty we obtained in our Observations The Seventh Experiment Of Freezing a Piece of Ice to a Table GAssendus Writes and it is very true That if a Plate of Ice be laid upon a flat Table and well sprinkled above with Salt it will freeze fast down to the Table we were desirous to make the same Experiment with Nitre but it succeeded not so as to shew us the least beginning of Adhaesion we have often observed in those stuck down with common Salt that we much more easily separated them from the Table by lifting them up Perpendicularly or at one end first as a Board nailed down is raised up with a Lever than they could be forced along parallel to the Plain moreover the Water on the under-side of the Ice was Salt and that side also thereof was Opake and covered with a white hoariness made of innumerable small particles of Salt and brought to the Light it appeared rough as if it had been prettily razed with the point of a Diamond like the Glass of those Vessels which from the Artificial similitude they have to Ice we call Ice-glasses The Eighth Experiment Of freezing the Dew upon the outsides of Vessels THat Dew which covers the outsides of Glasses containing any cold Liquor or Ice is sometimes observed to congeal there and the same happens when the Ice or Snow in the Vessel begins to alter with the strong Water or Salt there is also an Exhalation or cloudy moist Vapour rises up as it seems from the bottom of the Vessels whence proceeds a very cold air which besides that it sensibly affects the hand is likewise more discernable by the agitation which it causes in the flame of a Candle brought near it This Experiment we repeated by putting Ice sprinkled with strong water and Salt in several Vessels of different Figures and Metals to observe if either the one or the other afford any variety in the smoaking and as to the materials we could not perceive any diversity whether the Cups were of Glass Earth Wood Metal or precious Stones But as to the Figure it seemed to us that whereas in Beer-glasses and all other tall narrow Vessels the smoak began above on the contrary in wide bouls it smoaked from the bottom freely upwards for a short space In a Golden Boul we observed an effect which ought to be Vniversal in all Vessels tho it is less observable in some by reason of their shape it was this when the smoak ceased that crust of Ice began to let fall after the manner of dew a fine Ice like poudered Glass and continued till the ice in the Boul being dissolved that thin outward covering likewise melted The Exhalation said to proceed from the ice seems very different from that of any combustible Matter and much resembles the Morning mists that rise from the Earth The Ninth Experiment Of Reflected Cold. WE were willing to try if a Concave Glass set before a mass of 500 l. of Ice made any sensible repercussion of Cold upon a very nice Thermometer of 400 deg placed in its Focus The truth is it immediatly began to subside but by reason of the nearness of the Ice 't was doubtful whether the direct or reflected rays of Cold were more Efficacious upon this account we thought of covering the glass and whatever may be the cause the Spirit of Wine did indeed presently begin to rise for all this we dare not be positive but there might be some other cause thereof besides the want of the reflection from the Glass since we were deficient in making all the Trials necessary to clear the Experiment EXPERIMENTS Touching an Effect of HEAT and COLD Lately observed as to the Alteration of the inward Capacity of Glass and Metalline Vessels WE said in the Experiments of Artificial Freezing that the first Motion observed to be made by the Liquors exposed in Vessels to freeze was a small rising up there called Rise upon Immersion because it happens upon the Vessels first touching the freezing mixture and you must know the contrary to this is observable when it is immersed in hot Water for the Levels of the contained Fluids sensibly subside and then as it were take time to Rise again which they do with a quick Spring up to the degree they stood at when first immersed in the hot Water and thence successively rise as the heat received continues to rarifie lighten and raise them On the other side tho they are raised upon the first immersion into cold Water or ice yet they not onely subside again to the former height but continue to do so for many Degrees till at last sometimes after a little Rest sometimes without any they all remount Oyl and Spirit of Wine excepted until the whole freezing is finish'd This Effect was by some attributed to a cause much favoured by several following Experiments their apprehension was That the appearance of this sudden motion in water and other fluids was not really from any intrinsic alteration of rarity or density at that moment wrought in their natural temperament by the power of any Tab. 15. p. 105. contrary quality of the outwardly applyed ambient which some by a noted Word call Antiperistasis but rather to speak first of the subsiding upon the immersion of Vessels in hot Water their thoughts are that it comes from the fixing of several volatile Corpuscles of the fire evaporated from the hot Water into the external pores of the Glass which as so many wedges forcing and separating the parts thereof must necessarily distend and enlarge the internal Capacity thereof till they find a way through the hidden Passages of the Glass to the Liquor therein contained That on the other side Cold binding up and contracting those pores of the Glass makes the Vessel become too scanty for the bulk of Water in it before that bulk of Water yet unaffected by the Cold contracts likewise In fine that the
difference was 26944 gr which was the absolute weight of a bulk of Water equal to that of the whole Ball and Lead Then pressing the Ball together as much as its thickness would bear without letting the Air out and weighing it in the Air with all the Lead 't was found 31209 and this we concluded was the absolute Weight in uncompress'd Air as that was which was in the Ball before it was battered together In this State all being put into the water again and weighed 't was found gr 12518 which substracted from gr 31209 the weight of the Ball prest together in the Air there remained gr 18691 the weight of a bulk of water equal to the bulk of the same Lead and battered Ball. This Weight then of gr 18691 being substracted from the other of gr 26944 left 8253 gr which was the Weight of a bulk of water equal to such another bulk of Air as weighs 7 gr which bulk was equal to the diminution of the bulk of ball by the battering whence we concluded That the Weight of that sort of Air which we weighed is to the weight of so much water as 7 to 8253 that is as 1 to 1179. This Experiment being by us repeated at divers times the Proportion was not always found the same Indeed the variations have not been great consisting in one two or three Hundreds of grains more or less Which is all we can pretend in making the Comparison between one body that as we may say never alters in its weight and another never twice the same EXPERIMENTS Touching some EFFECTS of Heat and Cold. The First Experiment Of a Steel Wire seeming to grow lighter by being heated PUtting in the Essay-Scales two Steel Wires of equal Weight the one heated the other cold it seemed that this was heavier than the other but holding a lighted Coal or red-hot Iron near it it soon came to an aequilibrium with the hot one The same would have happened if they had been of Gold or Silver or any other Metal likewise if a lighted Coal be held over one of the Basons of a pair of Scales when empty it raises it and if held under it it causes it to descend For all this some of us could not apprehend how the bare heating could any ways alter the usual weight of the Metal nay 't was thought by some that the Pressure of the Air might have its part as well as any other cause in producing this Phenomenon The Second Experiment Of the vast force of Heat in raising up an included Liquor HAving filled with Sp. vin half of the Vessel AB whose slender part was 35 8 10 Inches long with two Sealed Balls of equal capacity we set the Ball A in a Glass of Oil over the Fire and the Sp. vin began to give notice of its Rarifaction by Rising but afterwards when the Oyl boil'd very fast it retired all into the upper Ball leaving that below quite empty with the lower half of the Cane It is also necessary to promote this Effect besides a strong Fire to blow the Coals continually about the Glass this must be done through the hole of a Plank serving to defend the Operator behind which also the Observer must stand to look thorow a Glass in the same Plank for when the Sp. vin is all forced into the upper Ball 't will be thrown off and not onely that but the lower will be burst with such force as one time amongst the rest making use of a brass vessel instead of the Glass for the Oyl it broke the bottom thereof and tore off a Band of Iron of the thickness of a Crown and crack'd a Stone in the Pavement But we made choice of Oyl and of Glass Vessels because their Transparency makes the Procedure of this admirable Effect more visible Else Wax Pitch or Lard or it may be any unctuous Matter may produce the same Effect The Third Experiment About Antiperistasis TO do something upon the score of Antiperistasis we filled with Ice finely powdered a Leaden Vessel and putting thereinto a Thermometer of 50 deg we let it stand still and it composed it self to about 13 ½ deg Then we plunged the Vessel into a Cauldron of boyling Water regarding nicely the Thermometer if in that instant that the Ice became encompass'd with its contrary it then gave any shew of greater Cold by subsiding But that as often as we repeated the Experiment was never seen to alter a hair nor was it ever observed to rise when the Vessel being full of hot water we plunged it in water mix'd with Ice nay then it was readily seen to subside for as much as the Fluid water more easily gave a passage to the Quality of the Ambient than in the first Experiment the Ice could do Nor let it be thought that all the Care possible was not taken to prevent the Air Encompassing the Thermometer from receiving any alteration upon immersing the Leaden Vessel in Different Ambients the said Vessel being let into a Plank which was very broad round it and so cut off all Communication between the bason under it whereinto the bottom was immersed and the air above but for all this we observed no difference from what is related The Fourth Experiment Whether Cold be caused by an intrusion of Frigorific Atoms TO gain some light Whether the chilling of Bodies were caused by the insinuation of any kind of peculiar Atoms of Cold as the opinion is They are heated by those of Fire we caused to be made two Glass Vials like each other with very slender Necks being sealed Hermetically we put one of them in Ice and the other in hot Water letting them remain some time and then breaking the neck of each off under Water we observed in the Hot one a Surcharge or Repletion from something got into it observable by the Bubbleing of the Water from a strong breath issuing from the Vial as soon as ever it was broke open Some might think the same should have happened in opening the Cold one if the Chilling of the Air therein had proceeded after the same manner as the heating of that in the other i. e. by the Intrusion or soaking of the Atoms of Cold exhaled from the Ice through the invisible Pores of the Glass but the quite contrary happened for instead of breathing forth any surcharge of Matter it shewed an emptyness or loss of something if there was not a condensation of what was there since it suck'd in so much Water in place of it The Fifth Experiment Of heating and cooling of Water by Salts c. And of hot and cold Ebullitions c. VItriol the Spirit being drawn off remains like a Tartar or Grumous Body of a lively Fire colour which with a long and continued Fire distills a blackish Oyl almost like Inke highly corrosive This being mixt with Water in a certain proportion produces an immediate Heat which increases without raising any Bubbles or
with the deniers of a Vacuity And since many Experiments have been made for this end as well what is related by others as what has been invented by our Academy the success shall be faithfully set down our Custome being always to deliver the Matter Historically and not to defraud the Inventors either of their Invention or due praise An Experiment Of Mr. Robervals in favour of the Airs Pressure upon Inferior Bodies tryed in our Academy LEt there be a glass Vessel A to the bottom of which BC perforated at D let the Cane DE 46 Inches long be affixt over this hole set the square glass F then close the Vessel A with the glass Cover GH having an open nose HI and a hole at G through which let the Cane KI be put open at each end and about 46 Inches long or not less then 30 let this down into the Glass F but not quite to touch the bottom and fasten it there with Mastic or other Cement at the fire to the hole in the Cover G this Cement or Paste is made of Brick reduced to an impalpable Powder and incorporated with Turpentine and Greek Pitch 't is admirable to stop Glasses to exclude the Air let it be luted close with the same round about where the said Cover and Vessel joyn and cover the lower mouth E with a Bladder Then pour in at the upper end K so much Mercury till running over the Glass F it falls upon the bottom BC and thence by the hole D fills the lower Cane ED and after that the whole Vessel A the Air having its way out by the open Nose HI which when the Mercury begins to run through it close well with the Bladder I and lift up the whole Cane to K till a little runs over that not the least Air may remain when closed which do with the Bladder K. Lastly open the other Bladder at the Mouth E under the Superficies of the Stagnant Mercury MN into which the Cane is immersed and immediately the upper Cane KL and the Vessel A will empty themselves the Glass F and OP part of the Cane DE being about 28 ½ Inches above the Level MN remaining full This done the ingress of the External Air upon opening or pricking the Bladder I will immediately suppress the Cilinder of Mercury OP into the lower Vessel and raise up another QR from the Mercury in the glass Cup F into the Cane LK equal to the former OP and therefore 28 ½ Inches long and this Cilinder will not subside until the External Air entring at the top K rushes in upon it through the Cane LK If in this Vessel A a little Bladder be enclosed taken carefully out of a Fish the Air that is Naturally therein being first expressed so as very little be left in the folds thereof and then the Orifice well tyed together as soon as ever by the subsiding of the Mercury the Bladder shall be in vacuo that little Air remaining in it will swell and distend it nor will it shrink again 'till by opening the Vessel at K the External Air gets in to press upon it But we have observed more clearly the like Expansion of Air in vacuo in a Vessel made after another manner as ADB wherein a Lambs Bladder squeezed together and almost wholly discharged of Air is inclosed thus fill the Vessel with Quick silver by the mouth D and tye it over with a Bladder the lower Mouth E being before stopt with the Finger then immersing it into the Quick-silver in the Vessel FG open the Mouth E and let the Quick silver subside then will the Bladder C hung by a Thread in the empty Vessel ADB swell it self and so continue till by opening the Mouth D the External Air enters a the Top which at the same time will bear down the Cilinder of Mercury into the Vessel at the bottom FG and press together the Bladder Likewise if in closing the Mouth D there be put upon the Mercury a little froth made with whites of Eggs or Soap-suds still as the Vessel ADB empties it self the Air imprisoned in these small bubbles will so swell them that at length breaking through its thin Confinements it shall be at liberty and quite released from the Liquor which will fall down upon the Mercury like Dew separated from that fine steame of Air contained in the froth Tab. 3 p. 19. Experiments Alledged by some against the Pressure of the Air and the Answer thereto THere have been Two Experiments from which some of our Academy judged a considerable Argument might be raised against the Pressure of the Air upon Inferior Bodies and the Effect of sustaining Fluids attributed to something else One was by covering the Vessel A and likewise the Cane with a great Bell of Glass BCD pasted down close to a Table round the edges for then they imagine that if it were true that the weight of the whole Incumbent Atmosphere of Air did protrude the Mercury into the Cane and counterpoise it with its weight by defending with this Cover of Glass the Stagnant Mercury from so great a Pressure the small and scarce sensible weight of the little portion of Air included within the Bell must of necessity be unable to keep the Quick-silver at the same height whereto the momentum of so vast a space of Air had raised it but notwithstanding this they never observed it to subside a jot from the usual height EG The Second Experiment was of the same Nature but more Artificial We fill'd with Mercury a small Vessel AB which at first was made without the Beak CD added afterwards for another Experiment and plunged into it when full the Cane EF and making the usual Vacuum there was poured out from the Vessel AB a small quantity of Quick silver so that a little Air might be in the space AH to bear upon the Stagnant Level HG and then the Weight and Pressure of the External Air was kept off by closing carefully with the afore-named Cement the round space A between the Neck of the Vessel and the Cane and yet in this case when the bulk of the External Air was so lessened to nothing almost we saw no sensible abatement of the Mercurial Cilinder IF below the usual height But the Assertors of the Airs Pressure answer these Experiments thus That these Events on the contrary greatly favour their Opinion for the immediate cause as they say that forces and powerfully sustains the Mercury to the height of 28 1 ◠Inches is not the weight of the Incumbent Air which indeed is taken off by the Bell in the first Experiment and by the Cement in the second but is in reality an effect of Compression which was produced and wrought in the Air contained in BCD Fig. 1. and in AH Fig. 2. by that weight before they were Cemented close whence 't is no wonder that the Quick silver subsides not from its usual height
Experiment To shew more evidently that where the Pressure of the Air is wanting the bearing up of the Fluid is lessened in a Cane of any length and upon the return of the same Pressure raised up again Tab 5 p 29 Note that KL is about the fourteenth part of the whole height of the Water ML for what Cause may be told presently but when it does exceed it as it may sometimes happen 't is from two Causes First either the Water wherewith the Vessel is fill'd was not poured in so hot that the vacuum left by it in condensing is capable of receiving all the Quick silver falling from the Cane EF for when the space AI left by the Condensing Water is fill'd by the subsiding Mercury which falling into the Vessel GB raises all the Water there can no more Mercury descend out of the Cane EF and so it will be above 1 14 of the height ML Or Secondly the other cause may be when this void space AI is indeed sufficient for the Mercury in the Cane but not for the Air which may rise either from the Mercury in the Ball or from the Water in the Vessel which air requiring a larger field to expatiate in theâ— the void AI may possibly make some impression upon the Superficies of the Water and so communicate it to the Cane and bear up the Mercury a little higher than the bare Weight and Pressure of the Water would have sustained it at An Experiment From whence is shewn the efficacy which the Pressure of another Fluid joyned with the Air has upon the sustained Mercurial Cilinder THe Vacuum being made with the Cane ABC wherein the simple Pressure of the air raises the Mercury to D the usual height of 28 6 10 Inches pour Water upon the Stagnant Level EB and fill it up to A and you shall see the Level D raised to F and the space FD will be 1 14 of the Water AB poured in and that because to the weight of the Cilinder of Mercury DF the weight of the other Cilinder of Water will upon trial be found equal having the same Basis and of the Height of AB But if instead of Water the same space AB be fill'd with Oyl the Mercury will rise to G onely if with Spirit of wine to H whence we may from the proportion of the height of the Fluid AB encompassing the Cane to the height of the increase caused by that Fluid in the mercurial Cilinder above the first Height of 28 6 10 Inches caused by the air find the Proportion of Specifick Gravity between the mercury and any of the Ambient Fluids And likewise as easily that of the Specifick Gravities of the Fluids in respect of each other The same may also be obtained without a Vacuum with a plain Cilindrical glass AB in the former Fig. into which by putting a little mercury and the small Cane AC now supposed open at each end and then pouring an equal quantity of several Fluids seperatim upon the Superficies of the mercury EB and all to the same Height suppose A from the different heights of the mercury in the little Cane FG HD caused by their respective gravities we may not onely have the Proportion of their Specifick gravity with the mercury but also that of the Fluids compared with one another Note that in this and all like Experiments where it happens that the inward or outward Level of the mercury is altered by the Pressure of some fluid or otherways then the Letters pointing at those operations in the Figures are supposed to be removed to the places requisite and successively follow the Level as it gradually moves from place to place An Experiment Shewing that where the Air presses not at all a Vacuum may be made not onely with Mercury but also with Water to any height of the Tube provided less than that whereto it used to be sustained by it LEt there be a Glass Vessel AB containing about 6 l. of Water and the Mouth A big enough to receive the Cane CD 22 9 10 Inches long sealed at C but Obliquely open at D this Cane must have at A the place whereto 't is let down into the Vessel AB two small Anulets of Glass close together that the Bladder with a hole therein may be tyed very fast between those two Rugs then fill the whole Vessel AB with Water as hot as possible and the Cane CD with cold put upon it at the lower end D the Plate of Glass E fitted to shut the Mouth of the Vessel AB Immerse the Cane therein turn down the Bladder gather it together and bind it close about the Neck of the Vessel having first prest out the Air from its Folds Now as the Water cools part of the Vessel FG will be empty and likewise as in the former Experiment part of the Cane CH where the Water will rest nor move but upon some alteration of the External Heat and Cold but upon pricking the Bladder the Air forcibly entring upon the Level of the Water in the Vessel will refill the Cane as at first It was thought by some that the water in the Cane does not fall at first when the Vacuum is made to the same Level with that in the Vessel supposing the space AG capable of receiving it it may be from a cause mentioned in a foregoing Experiment i. e. from some Air which raises it self from the Water into the void space perhaps too narrow for its full Expansion whence they imagine that if the Experiment were made with wine oyl spirit of wine and other liquors from a greater or lesser Vacuum remaining in the Cane it might be determined which of the Fluids has most Air dispersed through its Particles An Experiment First made in France and after by our Academy whence 't is probable a more cogent Argument for the Pressure of the Air may be drawn M. Pecquet in his Book of New Anatomical Experiments writes that it has been observed by many that the height of the Mercurial Cilinder in Vacuo varies according to the places where the Experiment is made whence in higher places 't is less and in lower places and deep pits greater provided the height be pretty considerable as that of the highest Mountain of Auvergne at the top whereof the Mercury wants much of the usual height which has been said to happen because the higher Air which is found upon the tops of vast Mountains having a lesser weight upon it makes a more faint Pressure nor is able to raise the Mercury to that height whereto the lower Air of Valleys and Plains easily mounts it Howsoever the truth of this assigned cause may prove of which 't is not at present our intent to discourse yet we have observed the very same Effect on the highest Tower at Florence which is 271 Foot high as likewise on divers of those small Hills which surround the City and we find it
the Mercury rose in the smaller Leg AB and then upon admission of the air could observe no alteration This Experiment was often repeated always with the same success Lastly They that took the raising of Fluids to a determinate height to be an undoubted Effect of the Airs Pressure were desirous to see if the air which presses upon the Stagnant Level when forced to pass through the hole of a very small Cane and must necessarily do so to exert any Pressure comes thereby to be so weakned and lessened that any observable alteration follows in the height of the Fluid so pressed which they thought would probably happen because if one Momentum were weakned the other must certainly preponderate and so alter the first Aequilibrium To this End there was taken the Cane ABCD whose height AB was 46 Inches and the Return BC 11 ½ Inches drawn to a greater Degree of smallness than is represented in the Figure this being open at A and D was filled with Mercury at the Mouth A till it came to D the Mouth of the Return which we then sealed at the Flame of a Candle and compleated the filling of the Cane to A and tyed it over fast with a Bladder then we broke off the End D and the Mercury began to run out very slowly contrary to what we have observed when the air pursued it at the other end whereas instead of air the Cane had now a vacuity which increased gradually from A so that the Mercury was no otherwise forced out but by the weight of that which was above 28 6 10 reckoning from C towards A and it immediately stop'd when it came to F the very same height above C as the Mercury was off in another Tube immersed in a large Vessel at the same time After this holding the Cane Perpendicular to the Horizon by lifting it gently up and down we caused a Motion in the Mercury so that by the Vibration of it backward and forward in the two Arms of the Vessel there ran out at each Vibration a little Mercury at the Beak D so that when the Cane and Mercury were at rest there remained a small part of the little Cane empty of Mercury GCD So the Air pressing upon G tho strained through so narrow a passage as D yet had not lost so much of its force as to cause any sensible abatement of the Height of the Cilinder F C. From all these Experiments and some other of a like Nature which we have now no time to relate some thought they saw good grounds to Affirm that That Opinion of a more Languid Pressure made by the air through so narrow conveyances taken absolutely so is not sufficient to produce this and the like Effects but they believed That there must be at least allowed some other concurrent Cause An Experiment Of Water in Vacuo THat Noble Observation of Mr. Boiles of the boiling of warm Water in Vacuo made us above measure curious not onely to see so rare and surprizing an Effect but also gave us an hint and desire to try the same Experiment with simple water and also with Water brought to as great a Degree of Cold as it is capable of without Freezing There was put into the Vessel represented by Fig. 5. Tab. 10. a quantity of natural water unaltered from its ordinary temperament in this after the Vacuum was made there appeared a shower of small drops which tho they were in great Plenty yet came very slow and the Water lost nothing of its Transparency their Motion was upwards till the Showr gradually ceasing the Water became sedate and quiet as at First The warm Water as soon as ever the Vacuum was made began violently to boil up toward the top of the Vessel with a noise not unlike that made by a Cauldron boiling very fast but upon opening the Ball and taking out the included Vessel we could not observe any heat acquired by this Ebullition The chilled water threw up four or five small Bubbles and then rested without any other sensible Change or Alteration Note that upon the admission of the Air the shower of small Drops ceased immediately in that Water of a natural Temperament as likewise the boiling of the warm water An Experiment Of Snow in Vacuo AT first we put in a small piece of Snow of which upon the fall of the Mercury there scarce appeared other than the melted Water This so hasty dissolution thereof seemed strange to us wherefore to make the Experiment more clear we repeated it with a larger piece made somewhat Cilindrical as long and big as could be put into the Ball which being filled with Mercury we thrust the Cilinder of Snow into it But slipping out of his hand that immersed it and so swimming upon the Mercury we might perceive that in the very act of Immersion the Mercury had preyed upon and eaten off a good part thereof and the dissolved Water swam upon the Mercury So we concluded that it was the Mercury which melted the first small piece of Snow so suddenly and not the Vacuum as at the first view it seemed to be wherefore putting the Snow in again closing the Vessel and making the Vacuum the little that remained was as slow in Dissolving as it used to be in the air This Experiment was made in the Summer so that the Snow was not in Flakes Solla we call the Snow at Florence when it falls like Down before it is frozen together but some of that taken out of the Conservatory where it was trodden down and pressed together An Experiment Of the Dissolution of Pearl and Coral in Vacuo THis Experiment we owe likewise to Mr. Boile which was after this manner Pearles and Coral as is well known are dissolved in Vinegar Tho this Action proceeds very slowly in the open air and consists in the curious discharging of very small Bubbles which rise from Bodies of the Pearl and Coral themselves yet they do not Rise so thick as to hinder the Transparency of the Vinegar especially from the Coral which if not finely powdered is much slower in Dissolving but Pearls being softer afford a greater plenty of Bubbles We desired to see each of them severally in Vacuo and observed so great a quantity of Bubbles to arise from each that the Vinegar was raised all in froth and run over the Vessel which therefore shewed as if it had been full of Milk or pure Snow Then we gave admission to the Air whereby the froth was immediately sunk and the Vinegar with its Natural Transparency began to act as before We will not omit here an Effect accidentally observed in this Dissolution which was this The Pearls when they sink to the bottom gather into one or more little bubbles of Air which naturally rising up carry the Pearl with them but as soon as ever the Bubbles rise above the Vinegar and by the chock of the Air break their Covering is curiously scattered about
stiff against the Instrument and at last both were loosened so that the Cross being at liberty fell down upon the Table whereon we set the Instrument within the Circumference of the Ring After this pouring the hot Water out we fill'd it with a mixture of Salt and Ice dissolved and it not only held the Cross again but with greater firmness than at first The Fourth Experiment To find the same Effect in Metals HAving bent a small Plate of Tin like a Stirrup and hung it up so as the two Extremities might touch a Plane put under them upon which we drew two Lines where the aforenamed Extremities must necessarily strike if they had been prolonged we then put a live Cole over the bending of the Plate and attentively observing one of the Points we discerned that by little and little it parted from the line drawing within it and this was when the convex of the Plate onely being heated dilated it self and the Concave was contracted but when it had penetrated which it soon did the whole thickness of the Tin being then equally dilated the point not onely again reacht the Line but passed beyond it more or less in Proportion to the Heat communicated by the Fire to the bending of the Stirrup The Fifth Experiment To observe by the Sound the like Dilatation in a Stirrup of Glass WE fitted a Minikin to a broad Stirrup of Glass as in the Figure and tuned it an Octave to the string of a Guitarre and applying the heat to it after the same manner as we did to the Stirrup of Tin when it had not yet affected the Concave Superficies thereof but onely the Convex Tab. 16. p. 110. the Tone was flatter because as in the foregoing Experiment the aperture was lessened and consequently the string slackened but when the heat had penetrated quite through the String was straitned so as the Sound was sharper than the first tuneing The Sixth Experiment Discovering the same Effect more clearly to the Eye WE fastned to the same String with a bit of Thread a small Leaden Plummet and put under it a little Plate of Glass so as not quite to touch the Weight and applyed fire to the usual place the Effect as to the stirrup was the very same as at other times for being at first drawn together the Cord became slacker and the Weight Rested upon the plate of Glass but at last extending the Aperture it strained the Cord and raised up the Plummet the contrary Effect was wrought by Ice made use of instead of the Coal but sensibly less in proportion as its activity is less than the fires The Seventh Experiment Shewing the same effects in Wire strings A Leaden Plummet being fastened to a nealed Brass-Wire and hung over a Glass Plate at a little distance therefrom drew nearer to touch it as the Wire became heated by applying a lighted Candle to it and still retired from it upon every little Rubbing with Ice In like manner two wires of mixt brass tuned unisons so that one being struck the other sounded were made discordant either by approaching to one of them a live Coale or a piece of Ice that by lengthening the wire made the Tone flatter and this by shortning it sharpened the Sound thereof The Eighth Experiment Whereby from the appearance of a contrary Effect 't is confirmed That the first Motion of Liquors comes from the Capacity of the Vessels being altered in the instant of Immersion IT may happen upon the first Immersion of Vessels into the Ambient Hot or Cold Body that the Level of the contained Liquors shews a different Effect from that before-named that is That it may immediatly rise in a hot Ambient and subside in a Cold one this will be always if the Vessel be made in the shape represented by the Figure in this upon the first touch of warm Water the Liquors will presently Rise because in the lateral Angles being very strong and thick of Metal in comparison of the hollowed faces the heat acting first upon the outward Superficies lessens those Angles as we said before it does to the Stirrup of Glass and so necessarily comes to stretch the thinner hollowed parts which Dilating inwards happen at first to lessen the Capacity of the Vessel and to raise the Liquor in the Neck which falls again from that space new filled when the heat has penetrated the whole substance of the Glass and the Vessel begins to enlarge it self uniformly returning to its first size and larger and at last the Liquor Rises again when impregnated with the fiery corpuscels it begins to Rarifie And it is manifest that the contrary to this is observed from Cold the same causes acting contrarily And Note That the Capacity of the Vessel was lessened by the pressure of the Hand onely made upon two opposite hollow sides nor could the Rising of the Liquor be attributed to the heat of the Hand Rarifying it for it was raised after the same manner by pressing the Vessel with two pieces of Ice The use of the next Instrument may easily be comprehended from its Figure being onely a Plate of Steel perforated with Circles of divers Measures to observe the different increasings caused by different Degrees of Heat given to the same or several Conical Rings of Metal The Ninth Experiment To shew That a Vessel may be distended not onely by Heat or by soaking up of moisture but also by Weight THere were made Two Vessels of Glass the one Conical the other Pyramidal and letting them into a thick Table we marked round the outside of the Vessels how far they sunk down then taking them out we fill'd them with Mercury and put them again into the holes in the Table but they would not go down so low as the Mark made at first because they were distended by the force of the Mercuries weight EXPERIMENTS About the Compression of Water THat Experiments do not always reach the truth aimed at is not from any defect of the Idea conceived of them in the mind but rather happens from the necessity we have of material Bodies and corruptible Instruments to put our Conceptions in Practice which though of themselves unable to blemish the Theory and Speculative part yet through the Defaults in their substances are not always capable of seconding our thoughts but we must not hence conclude the Experimental Method fallacious in the Quest of Natural Events for though by it we may sometimes come short of the very depth of that Truth which we first sought after yet it is hard if it does not give some glimmerings and marks to discover the falsity of any contrary supposition This has been our Fate in our Research Whether water can suffer any Compression as air does in which attempt for as much as the weakness of our Vessels came short of affording us a perfect knowledge of the Truth we making use of Glass ones as most fit because