Vessel being first sensible of Cold or Heat by shrinking or enlarging it self also first is the true cause of that Phenomenon of the Rise or Fall as it becomes more strait or large to the contained Liquors yet not vitiated by the quality of the ambient This Opinion was rendred more probable to us by the following Experiment An Experiment Proving That in the Instant that the External Heat or Cold dilates or contracts the vessel yet then the natural temperament of the Liquors therein contained is unaltered WE included in a Globe of Glass filled with Water several small bubbles of Coloured Glass empty and sealed Hermetically these were all near the Specifick gravity of the Water by means of the air they had in them whence the Floaters upon the top of the water upon the least breath of warmth sunk down and those at the bottom upon any accession of Cold mounted upwards hanging this Instrument in the air and suffering the bubbles to rest we began to approach to it underneath a pan of Water heated and after that of Cold Water mix'd with Ice well broken And though upon the application of these different Ambients we observed the same Effects in the Level of raising it self upon the touch of the Cold and subsiding upon that of the hot Water yet we could not find when the water seemed condensed and contracted that any of them at the bottom rose up nor when the Water seemed rarefied and enlarged any of the Floaters sunk to the bottom but these were observed to fall and those to rise when the Water after its abatement upon the first impression of heat began to rise again and when after its rising upon the impression of Cold it began to subside again an argument to insinuate that the water and so any other Fluids in this first Motion do not really move themselves but onely obey the alteration of the Vessels they are contained in Yet it may be objected That these first alterations did really proceed from the inward changes of the Liquors which tho discernable by the Eye by means of the small Neck of the vessel yet were not great enough to be discerned in changing the aequilibrium of the Bubbles of which it may be thought that in that very instant they began really to move though in their first parting from Rest the Eye could not perceive it To this is answered That the true Rarifaction and the true Condensation of the Water that is able to make it rise or fall so very little a space as it does rise or fall at the entrance into the Icey mixtture or hot Water is sufficient to alter the Aequilibrium also between it and the bubbles apparently to the Eye And indeed when the Water really rises or falls from a true Rarifaction or Condensation the bubbles likewise begin correspondently to move before ever it comes to the same Degree at which the same bubbles remaining immoveable it stood at the instant of its first immersion Nevertheless the discovery of this Effect ought not to cause in us the least scruple of the truth of our Thermometers since the whole contraction or dilatation in Vessels containing an Ounce and half at most amounts but to a grane whence proportionably how small will that be in Vessels of a few granes content such as our Thermometer of 50 deg which are the most convenient and exact and upon that account most made use of to discover the Alterations of the Air Now to manifest by divers ways even to sense the Truth of this Phenomenon we made the following Experiments which first founded in the Theory are confirmed by the Effects The First Experiment Shewing the Alteration of the Size of a brass-Ring put in the Fire and in Ice its Figure still remaining unaltered THere was ordered to be cast a Ring of Brass and by turning it was fitted exactly to a Cilinder of the same Metal this was put in the fire for a short space and then being put upon the Cilinder while hot it was sensibly loose being dilated by the heat into a Ring of the same shape it was of before but its concavity was 9 100 parts larger when it had remained some time upon the Cilinder and had communicated its heat thereto between the increasing of that and the shrinking of the Ring by little and little as it cooled they not onely came to fit as at first but were so firmly united that before they were quite cold a considerable force was but requisite to separate them The contrary in all respects happened when we intensly froze the Ring The Second Experiment Whereby it appears that Bodies are dilated by the imbibing of moisture as well as by the insinuation of heat WE made a Conical Ring of Box whose concave Superficies was curiously turned and polish'd there was also made a stock or Conical Mandril of Steel turned and well smoothed and nicely divided with many circles Parallel to the Base fitting the Ring upon this we marked which of those Circles the bottom thereof just touched taking it off we let it lye in Water three whole days that it might have time to penetrate through the whole stubstance of the Wood then we put it on again and observed that the Concavity was stretch'd the bottom of the Ring falling much lower upon the stock than it did at first This Ring was made two several ways in one the Ligneous Fibres were Perpendicular in the other Parallel to the Plane of the Basis the first after soaking in the water kept its spherical Figure exactly the other came near to an Oval and put upon the stock sunk down much short of the former Observe to make these Rings of firm clear Wood that is without Knots and of an uniform hardness especially when the Fibres are cut transversly that so all being swell'd by the steeping their enlargment may be the more sensible Note also as was said at first that the Rings must lie so long in the Water as their whole substance may be penetrated for the Effect will be different if those that are but a little soaked on the outside be put upon the Stock because they will not slide down so far as when they were dry Therefore let them be well impregnated and satiated with moisture that their dilatation may be the more visible The Third Experiment Which discovers more evidently the readiness of Glass to contract and dilate it self upon Heat and Cold. THere was made a hollow Ring of Glass as in the Figure about Two Foot in Diameter with Two Funnels that when the Liquor was poured in at one the Air might have vent at the other then was made a Cross of Glass just to touch with its Extremities the Concave of our hollow Ring and filling the Vessel with hot Water by the Funnel as it proceeded in dilating it self so visibly either the one or the other of the Glass Rods lost their hold for they did not bear equally
deprived of that virtue and some thought that their plain Superficies had no part in the Effect seeing when the Diamond has depth tho smooth'd and polish'd upon the Wheel it draws vigorously whereas the flat Table-Stones that are shallow such as are set in Lockets at the end of Neck-laces commonly called Spere tho very large when strongly Rubb'd will yet not draw or if they do 't is so faintly that you must make them touch some hairs of the bit of Paper or Straw to make them raise it up yet 't is not to be doubted but some may be found that have a little force yet of these we at least were so unsuccessful as to find but few We indeed had one which by many trials for several days we were never able to make attract but a Year after desirous to see the same tryed again we took the same Ring in which the Stone was set and having but slightly rubb'd it as we used to do upon the Cloath as soon as ever it was held to the bit of Paper it drew it vigorously this same Effect was often observed with wonder by all those that the year before had often attempted in vain to make it draw and on the contrary as we said at first the fausets i. e. those that are ground of their own Octoedral Figure seldom or never failed In fine since Amber and all Electrick Bodies have been observed to be obstructed by a very thin Vail placed between them and the thing to be attracted therefore taking a sheet of Paper we made several little Lattices in it and the first of them was covered with a close Network of hair another with the Lint of a fine Rag a third with a Leaf of Gold the success was That the Electick Power of the Amber did not penetrate them EXPERIMENTS ABOUT Altering the COLOVRS of several FLVIDS THere is nothing more frequent amongst the Niceties of the Chymists than their Fantastic humour of changing Colours we indeed do not professedly meddle therewith and if any such Tryals were made we were moved thereto from the occasion we had of making use of some Liquors fit to examine the Qualities of Natural Springs Concerning which we will relate the little that came to our Knowledge again reminding the Reader That by the perfixt Name of Essays we would intimate That we do not presume we have examined these Matters with all the Experiments which may be thought on but onely barely given some hints of those things we were most inclined to take pains about The First Experiment Of altering Water WAter Distill'd in a Leaden Still thickens and muddies the Water of all Rivers Baths Fountains or Wells wherewith it is at any time mix'd and losing their Transparency they both look white like Whey onely Water Distilled in Glass Vessels and of Spring Water that of the Conduit of Pisa remains Limpid and Transparent But all those Waters so muddyed become clear and pure again by a few drops of strong Vinegar shook together with them The same Waters are changed by a dropping in of Oyl of Tartar and Oyl of Anniseeds which give the Appearance of a little white Cloud higher or lower therein which by shaking diffuses it self through all the Liquor and inturbidats it This also is brought to its former clearness by a small Quantity of Spirit of Sulphur which at first raises a few little bubbles Note That all Waters indifferently do not become turbid by the above-named Oyls and those Waters that are not altered by waters stillâ—d in Lead are likewise left Transparent by Oyl of Tartar and Aniseeds Moreover inflammable Waters Waters still'd in Glasses and that of the Conduit of Pisa are not at all changed from their Natural clearness and we find that in Waters generally held the lightest purest and noblest the little cloud is thinner and higher which is raised therein and onely in heavy Waters and those that are impregnated with Minerals or dreggy it thickens it like Milk whence some have pretended to prove Waters with some of the above-named Liquors for thereby is discovered the more hidden Quality of them and so their Goodness or Badness found If at any time the Thickness and Turbidness of the Water is very great and not to be Clarifyed by the ordinary proportion of Liquors it may be increased by some drops still agitating the Water till you see it become clear The Second Experiment Of Altering Wine OYL of Tartar not onely in Water but also in Wine produces the same Effect for through its Natural cleansing Quality as is known it makes a separation in all Liquors of what ever is mix'd with them from the purer parts by a sediment that it lets fall whence that which shews like a white Cloud higher or lower in the Water according to its different Qualities and Weight in all sorts of White Wines that we Experimented appears like a thin Cloud of a Red Colour which by shaking the Wine quits its first place and disperses it self uniformly throughout the whole Body it makes no other change in Red Wines than a little Tinging deeper especially toward the bottom On the contrary Spirit of Sulphur shews no alteration in the natural Transparency of the Wine and likewise restores it to those deprived thereof by the Oyl of Tartar The Third Experiment Of the Tincture of Roses A Tincture of Red Roses extracted with Spirit of Vitriol being mix'd with Oyl of Tartar shews a fair Green with a few drops of Spirit of Sulphur it ferments all into a Vermillion froth and at last returns to its first Rose Colour without losing its smell at all nor will it be again altered by dropping Oyl of Tartar into it We found the best way of getting the Tincture of Roses for this Experiment as follows Taking a good handful of dryed red Rose-buds we cut them and putting them in a Glass with one Ounce of strong Spirit of Vitriol stirred them together for a quarter of an hour in which time the Roses were well Macerated and the Tincture Extracted to this must be added at Three or Four times about half a pound of Spring Water still shaking the Glass till the very deep Colour of the Spirit being Diluted the Water is all tinged therewith then we let it stand an hour and so obtain a lively and beautiful Tincture of Roses To half an Ounce of this put Ten or Twelve drops of Oyl of Tartar and afterward as much Spirit of Sulphur which suffice to produce the Related Effects The Fourth Experiment Of the Tincture of Saffron WAter tinged with Saffron helped a little with the Tincture of Roses but not so as to lose its golden Colour changes green with Oyl of Tartar and again yellow with Spirit of Sulphur The Fifth Experiment Of Greens WAter Coloured with Iris Green mix'd with Spirit of Sulphur makes a Purplish Colour and with Oyl of Tartar takes its own again This Green is a Tincture taken from 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
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 their Transparency yet at least we gained this much that Water cannot be compressed with a very great force and so far we have proceeded That a power able to reduce Air into a space 30 times less than what it first filled that power not onely thirty times but a hundred nay perchance a Thousand times encreased was too weak to compress a quantity of Water a Hairs breadth or the least visible Space from its Natural Extent the Methods we took were those that follow TAb 17. p. 115. The First Experiment LEt there be at the Ends of Two Glass Canes AB AC two balls of Glass also the one larger than the other fill both with fair water to D and E and joyn them together with a Lamp remembring to leave a passage open in sealing them at A and to draw the beak AF very long and open then apply to each Ball a Glass full of beaten Ice burying them therein that by condensing the water there may enter as much air as possible into the Canes and the better to force it down you may rub a piece of Ice backward and forward upon the out-side of the Syphon DAE which by its Coldness contracting the air in the Canes there will enter in more to fill it at the Beak F then Seal it at a Flame and the contained Air will remain prest and thronged together after this as it is Sealed take the Ball B out of the Ice and at first immerse it in tepid Water next in warm and at last in boiling keeping the Ball C all the while covered with Ice to reduce the Water therein to the utmost condensation which suppose to be at E moreover indeavour to compress the Cilinder of Air GE to its greatest density by the force of the Water rising to G being Rarified by the received heat from the Water supposed to boile round about the Ball B now if the Water could suffer any Compression it ought to subside from the pressing Air below the Mark E but with us it still happened otherwise for when the Water at E was once reduc'd to its utmost Condensation by the Cold c. the force of the Air GE pressing thereon was unable to gain a Tittle and did sooner burst out the bottom of the Ball C than force the Level E a jot and when to add a greater strength to the Instrument we made the two Balls of Copper the Water in the Ball C has sustained the Force between the Air pressing at E and Solidity of the Metal with insuperable Resistance rather bursting the Syphon which must be of Glass to discover the Internal Motion of the Water joyned fast to the Copper with Mastick or the usual hard Cement The Second Experiment LEt there be prepared a Vessel of Glass AB contained about 6 l. of Water the Mouth large enough to receive a Glass Cane bound close about with Lead to keep it from bursting fill this Vessel with Water up to CD immersed the Cane EF open at each end therein and Soder it close at A with the usual Cement remembring to lift up the lower End a little from the bottom of the Vessel FB that the Liquor poured thereinto may have free passage into the Vessel then begin to pour Quick silver down the Cane into the Vessel raising up the water 'till the Vessel is quite full the air having its exit at the Beak H and to be certain all the air is gone let some Water out at the Beak H and immediately Seal it with a Flame noting at the same time the Degree the Mercury stands at in the Vessel IK afterwards pouring in more Mercury fill the Cane to the Top then if the Water by this force is compressed the height IK will gradually encrease as the Water yields we by a charge of 80 l. of Mercury in a Cane above 91 Inches long for so much our Instrument held without cracking could not perceive the Level IK raised an Hairs breadth the Water obstinately resisting the force of so great a momentum The Third Experiment WE ordered a thin large Vessel of Silver to be cast and filled it with Water cooled very well with Ice and screwed the Cover on with a very close Screw then we began to hammer the Vessel gently every where and the battered Silver which being so little Ductile did not at all thin and distend it self as refin'd Gold Lead and other soft Metals do lessened and comprest the inward Capacity of the Vessel by Degrees yet the Water for all this suffered not the least Compression for at every stroak we perceived it to sweat through the Vessel at all the little Pores of the Metal as Quick-silver when pressed with a piece of Leather spirts through in little drops This is what we thought worth relating of these three Experiments but are not yet able to say whether if the same Experiments be repeated in Vessels of greater strength and if the Rarefaction of the Water be Augmented in the first Experiment and so the Pressure of the Air or if the height of the Mercurial Cilinder be increased in the second or if in the last the Vessel be successively made of thicker Silver I say we are not positive whether the water may not at last happen to be comprest this is certain That Water in comparison of air resists the Compression we may almost say infinitely more which confirms what we said at the beginning of these Experiments That if Experience does not reach the very bottom of the enquired Truth yet it goes hard if it strikes not out some Light EXPERIMENTS To prove there is no Positive Levity ANcient and Famous is that Question Whether those Bodies that we usually call Light are so really in their own Nature and mount upwards from any proper tendency or whether their Motion be no other than a chase or flight they are forced to by more heavy Bodies which having the greater force and desire to descend and place themselves undermost press and as it were compel the other to rise This Opinion which chiefly seems to have been entertained in these latter Ages was yet not unknown to the Ancients Nay it was Asserted from rational grounds by many Philosophers in those times among the rest clearly by Plato in Timaeo and he advanced so far upon the probability of that thought that he not onely holds That the heavier Bodies force up the less heavy as Fire does Air but also the more heavy as Water in respect of Air when ever it is made lighter by the interspersion of Fiery Particles and this he seems designedly to insinuate in the above-cited Dialogue of Timaeus when he says That the fire rising from the hot Entrails of the Earth and not entring into a Vacuity thrusts forward the Air that is contiguous to it which not onely gives way thereto but even divests it of those moist Particles wherewith it ascends and then helps it forward and raises it up unto
in those of 100. deg especially of 300 deg the smallest Inequality and Error committed in making one with a large Ball and small Neck being very easie to be discovered so that they will shew great Disagreement and inequality when compared together The Fourth Thermometer THis Fourth Instrument has a Spiral Canale yet differs not much from the former indeed it comes not near the same Scale of Proportion it being impossible to draw so very long a Neck equal and of the same size and bore throughout the whole length because there is a necessity to pass and repass it often over the flame to bend it whence it cannot be avoided when the Metal is softned by the flame but the Cane will be straitned and contracted in some places and in others relaxed and swelled Blow then a Globe of a great Capacity with a very long slender Neck and Coyl it round as in the Fig. each turn being close to the other and rising but with a small Angle that the whole Height may be as little as possible and so less subject to be broken to pieces then let it have at the top another less Ball hollow and sealed at the Flame to be a receptacle for the Air in the Cane to retreat to from the pressure of the Water in raising it self lest for want of room and being every way closed it resists the ascent of the Water and so crack the Vessel after this manner may be had a very ticklish Thermometer and as I may say of so exquisite a sense that the least flame of a Candle in an instant shall be able to make the contained Spirit of Wine move swiftly which Effect will be so much more conspicuous as the Ball is larger which may be made very Capacious at pleasure without being tied to any Rule This Instrument being made rather for fancy and curiosity to see the Liquor run the Decimals of Degrees by the onely impulse of a warm breath c. than for any accurate Deduction or Infallible Proportion of Heat and Cold to be learnt thereby The Fifth Thermometer THis is more slow and lazy than any of the former which immediately answer to the least change of the Air but this is not so nice to move upon a small alteration yet since 't is made use of in divers Parts of Italy and other places we will not omit to say something briefly of its make To make it you must fill a glass Vessel with Rectifyed Spirits of Wine and immersing a Thermometer of 100 deg therein place it in Snow or Ice to cool it you must also put into the same Liquor many little glass bubbles blown and Hermetically Sealed at a Lamp these by reason of the Air contained in them will keep themselves floating upon the Surface of the Water and if by chance any one being a little heavier in Specie than Water shall sink to the bottom take it out and upon a plate of Lead with fine Emeril grind off so much of the end as will make it light enough to swim Then the Vessel being taken out of the Ice carry it into a Room where the Air is well heated by a Fire that the Liquor which before was very cold may receive equally on all sides the temperament of Heat So by little and little as the Liquor grows warmer and by Rarefaction lighter the Balls which at a more intense degree of Cold kept just upon the Surface shall begin to dive toward the bottom and at the same time the Spirit of Wine in the Thermometer shall creep up That Bubble or Ball thereof which sinks when the Thermometer is at 20 deg shall be reckon'd the first that is the heaviest because it descended when the Water was yet very cold and little or not at all altered That which sinks when the Thermometer is at 30. deg may be accounted the Second at 40° the Third at 50° the Fourth at 60° the Fifth at 70° the Sixth and Last or Lightest whence it appears that the Bubbles make a Scale of equal Differences that is from 10° to 10 deg as likewise whence this Instrument is more gross then the rest in that it shews by the rising and falling of the Bubbles the alteration of the Air but to every 10 th Degree of that Thermometer which is divided into 100° and to about every 4 th or 5 th of that of 50 deg and to every 40° of that of 300° Let these Bubbles so tryed and chosen And it would do well if they were of coloured Glass to be the more discernable in the midst of the Liquor be inclosed in a large Cane of Glass fill'd with Spirit of Wine but not quite to the top leaving some space for the Liquor to rarefie when the heat of the Season shall require it and then seal it Hermetically If the heat of the Room is not sufficient to make the Thermometer rise to 60 it may be helped by putting the Vessel in a Bath of warm water increasing the heat by gradual pouring in boiling Water if needful and so the Spirit of Wine contained therein will not be more heated in one part than another but take its temperature as gently and equally as possible The Description of an Instrument to discover the difference of Moisture in the Air. HAving already treated of those Instruments which serve to shew the Alterations happening to the Air from Heat and Cold we come next to Describe another useful to discover the Changes which the Air is subject to purely from Humidity and though there may be many and different Instruments of this Nature which have been Invented by several Ingenious Persons yet we will describe this one Of which since it had its being first in this Court we will say something out of gratitude concerning its Invention and Use though perchance it is wrote of by others It is part of a Cone of Cork hollow within and pitched and covered on the outside over with Tin at the smaller end it is inserted into a Vessel of Glass with a Conical Point shaped as in the Figure and closed Hermetically The Vessel being so made and placed upon its Pedestal is to be filled with Snow or small beaten Ice the water whereof as it melts shall have its issue by the Pipe made in the upper part of the Glass The Vse of it is this The subtil Moisture carryed about by the Air adheres by little and little to the sides of the Vessel covering it at first but with a dew or mist till by the coming of more moisture it gathers into great drops and at last stealing down the sides of the Conical Glass drops into a tall Cup in the shape of a Mum-glass divided into equal deg and made on purpose to receive it 'T is evident as the Air is more or less full of moist Vapours the force of the Cold condenses a greater or less quantity of Water measured by the graduated glass Cilinder Wherefore desiring to compare
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
with a Wind Instrument because it receives its trembling not from Percussion as a Bell but from the Impetus of the Air rushing out of it And because it might be too hard a Task if not impossible to place such an Instrument in a Vacuum made with Mercury we resolved to enclose it in a Vessel exhausted of its air by Attraction so as it has been lately practised by Mr. Boile with admirable success in those his curious and noble Experiments among which this was thought of also though it was not put in Practice for want of a fit Artificer to make the Apparatus Now tho the Vessel can never be emptied so perfectly by that way as by Mercury yet the air is always so far Rarified as from the manifest difference which appears in those Effects that depend really upon the ordinary Natural Pressure of the Air upon them we may easily come to form a right Judgment what they would be in a perfect Vacuum We will here truly relate what we happened to observe confessing that it is more to shew the manner and Method we thought of to make the Experiment than for any certainty we were able to gain thereby since it may be said we rather failed than made the Experiment For this purpose we made a little Organ as ABCD of but one Pipe and with the Bellows having Communication with the Pipe by an hollow Conveyance in the Basis BC. This Organ we included in the Brass Box F and put the handle HI through the Mouth G of this Box. This handle we rested upon the Pillar or Prop KL when we had first put it through the Ring M sodered to a small Iron Rod passing each way through the boards of the Bellows and fastned to them so that by moving the handle this way and that way either the one or the other was opened and shut forcing the air into the Pipe Then taking a Piece of soft Leather and making an hole in it we put it over the Handle binding it fast upon the Mouth G and likewise gathering it together we tyed it about the Handle as in the Fig. so that all Ingress of the air might be prevented and through the pliantness of the Leather the handle easily moved every way All being so prepared and the Cover E Cemented on very close we began to exhaust the air out of the Box with a Pump screwed on to a Hole in the Cover N and at every Draught turning the Stop-cock O that when the sucker was forced down to drive out the attracted air at the valve and Nose P the air might not re-enter into the Box F and frustrate the Labour of the Operator After many draughts that the air became so rerified as the Leather which closed the Mouth G was quite drawn in and the Force of a very strong Man was unable to draw back the Sucker or Plug we began to move this way and that way the Handle so to convey the Subtile air out of the Bellows into the Organ-pipe and listned to the Sound But the Truth is we could not perceive it to differ at all not onely from that which was made in the same Box when shut up full of air in its natural state but also not sensibly from that made in the Box when we had by the Pump forced and condensed a great quantity of air therein Wherefore some did say jestingly either that the air has nothing to do in the Production of Sounds or is able to do it alike in any state An Experiment Of the Operation of the Magnet in Vacuo HAnging a Needle by the Thread by which the Bell was fastned before we applyed a Magnet to the outside of the Ball and found it was attracted at the same distance as when the Vessel was full of air An Experiment Of the raising of Fluids in small hollow Canes in Vacuo AMongst other Effects of the Airs Pressure some have reckon'd that of almost all Fluids rising up in small Canes therein immersed believing that the small Cilinder of air pressing through the little Cane upon any fluid suppose the Water acts more faintly by reason 't is lessened or straitned by the great Adhaesion of the Fluid to the inside of so small a Vessel as on the contrary they judge that the air which freely presses upon the large Superficies of the Fluid round the out-side of the same Cane being permitted to bear upon it with its whole force raises it therein until the Momentum of the Water raised together with that little Pressure within the Cane counterpoize that of the external air To have some light as to the Truth of this Discourse we attempted to see what the Effect would be in Vacuo We therefore prepared the former Ball as was directed for Fish Tab. 10. Fig. 1. that is by filling the upper half with Water into this we immersed the small Cane AB represented in the Table of its full bigness which was open at each end and had Cemented upon it in the middle an hollow Button of Glass counterpoised to keep the Cane upright in the Water Then closing the Mouth of our large Ball AC we made the Vacuum the Water standing to the midst of the Ball and the small Cane stood Erect by reason of its hollow Button and the Water rose in it up to C then the lower Mouth being stop'd with a Finger that the air entring might not empty our larger Vessel we unbound it above and opened the Mouth AC to see if the air being admitted to press upon the Water that greater and more violent impulse would cause any alteration in the Level C of the small immersed Cane but it did not After this Experiment 't was yet doubted that the wet received by the whole Internal Superficies of the little Cane when quite Immersed in the Water before the Vacuum was made might serve like Glew to detain the small Cilinder of Water CD whereto it might be kept by Adhesion also as well as it was before by the force of the External Pressure wherefore it was resolved first to rarifie the air in the Vessel which we intended to try the Experiment in that the first Immersion of the Cane might be made with the air already dilated and rarified and with the inside of the Cane dry that there might be nothing in it to raise more Water than that which the weak Pressure of that thin air was able to do and that afterwards reducing the air to its natural state and then Artificially compressing it it was thought we might discover some observable variation in the height of the Water contained in the Cane Tab. 1. p. 54. There was also made another Experiment which was this Within the Ball so often made use of we placed the Syphon ABCD so hung that when the vacuum was made it might remain upright in the midst of the Ball and full of Mercury we then observed to what Degree
insensibly be comprest as Tin Silver and Gold it self become more compact by being hammered but at last observing that whereas the Ball before freezing was flatted so that it would stand upon the bottom when it was taken out of the freezing mixture it would not stand upright every one was well satisfyed whence this happened and because it seemed to us perfectly Spherical to be the better assured thereof whether it would remain of its first Size if it did not burst in repeating the Experiment or whether it would stretch bigger we made a Ring of Brass exactly fitted to the Vessels greatest Circle All along in the freezing by examining it with this Ring we still found it grow bigger and bigger that pure metal by reason of its softness and pliantness still dilating and stretching it self and perhaps if it had been made of cast Metal the Effect would have been more conspicuous but being made of Two pieces it at last burst at the place where it was sodered with Silver and the Crack beginning at the Soder ranslanting down into the Gold also An Experiment To measure how great the force of Rarefaction may be in Water shut up in close Vessels to Freeze TO obtain this we thought of making a Metal Ball of brass like the former but perfectly round and according to our Estimation so much thicker that the force of Rarefaction should be unable to break it and filling it with Water to set it to freeze as before the Cover being fast screwed down This was done and at first we found that the Water was frozen without any running out or cracking the Vessel wherefore we put in the Lare and keeping it as near as possible of the same Figure there was taken off every where a thin coat of Metal and then 't was set to freeze the second time with water and not being burst also altho it was frozen we again turned off a thin skin from the Ball this Experiment we repeated with three Balls the thickest whereof is represented by the 4. Fig. which seemed to us the greatest thickness the force of Rarefaction in freezing Water could over-power having proceeded so far we were desirous to reduce this to the force of dead weight and the most probable means we thought of was to cast a Ring of the same Metals and hardness and exactly of the thicknes of the Ball turning the inside conical and fitting thereto an Iron Cone so that the Iron might rise about the breadth of the Ring above the upper Edg thereof being thus prepared we thought of putting the Ring over an hole made in the midst of a thick Stone Table something larger than the bore of the Ring we then thought to proceed to lay on Weights upon the top of the Iron Cone or at least force it down with Weights hung to an hook made at the lower End thereof that so the force being Perpendicular it might equally drive the Iron into the Ring and then leasurely adding small leaden Weights we might know the least Weight capable of bursting the Ring and to be secured that the bearing of the Ring upon the roughness of the Table might be no hindrance to its breaking we thought to fasten round the hole of the Table a Plate of Polisht Steel and smooth the under-side of the Ring that it might upon the least touch slip upon the Steel but because an immense Weight was but sufficient to Conquer so great a Resistance we thought to obtain our End by making the Experiment with several much smaller Rings but of different Sizes and with more managable Weights and so by examining the Resistance of these Rings and comparing the repeated Trials to come near the knowledge of what would break the first Ring of the same thickness of the Ball and by consequence the force of Rarefaction in Freezing These were our thoughts but still finding upon cutting our Balls that were crack'd in the freezing several inequalities and defects in the founding proceeding either from the wind or dregs of the Metal when infusion we were discouraged from Prosecuting the Experiment upon so many uncertainties nevertheless we forbear not to relate our intentions freely tho we came short of our End yet it may serve for an Advertisement to others not to take a wrong Path and perchance excite the Ingenious to find out a means to obviate these difficulties or a happier Journey another way Experiments To Measure the utmost Expansion of Water in Freezing The First Experiment WE made this Experiment two ways by Measure and by Weight that by Measure was after this manner We procured a glass Cane drawn as equal as possible we Sealed it at one End and filling it to a certain Mark with Water we set it in Ice very well powdered and incorporated with Salt to freeze then comparing the height of the Cilinder Frozen with that of the Cilinder Fluid having the same Bases the Proportion was found to be as Nine to Eight The Second Experiment WE did not think fit to rest satisfied with this one Experiment judging it little less than impossible to find a Glass Cane which has no other Rule to draw it by than the equal breath of the Artificer so truly Cilindrical as to take away all scruple of the Proportion of the Cilinders of Water contained therein wherefore to have a more Regular Vessel we took the Barrel of a Pistol and turned it within to the truest Cilindrical Figure attainable by a Material Instrument shutting the touch-hole with a Steel Screw and covering that with a Polish'd Steel Plate we poured in Six Fingers Water and thrust in a turned Cilinder of Box of the exact Size of the remaining part of the Tube well oyl'd and greased that it might not imbibe any Water when it was driven in so far that the Mouth of the Barrel was well stop'd we inverted the Cane that the Water might all rest upon the Base of the Cilinder and unscrewing the touch-hole we forced the Cilinder of Box in further till the Water began to run out then screwing in the Pin again we set the Barrel upright and marked how much of the Wood stood out and covered it with the Freezing mixture sprinkled with Aqua vitae which as is well known enforces the freezing very much When it had lain there about 12 Minutes the Mark made at the Nose of the Barrel upon the Box was raised the thickness of a Crown and presently after two more where it stayed tho we reinforced the Cold by a great quantity of fresh Snow and Salt after a full hour we took the Barrel out and found it so cold that we could scarce endure it in our hands whence we gathered it was throughly Frozen and that the rather because unscrewing the Touch-hole and striking the end of the Box Cilinder against the Wall we were not able to force it an Hairs breadth in and except a few drops at the Touch-hole we could not observe any Water
between the Cilinder and Barrel and by trying with a Piercer we found it Solid Ice for all this we were not certain the Water was all frozen nor could we be easily satisfied because of the opacous Tube And 't was possible some Water might get out at the Screw of the Touch-hole and so part of the Tube between the Cilinder of Ice and Box remain empty Or in fine the Water when at perfect liberty may Rarefie in a greater Proportion than it can do when under the constraint of a close Vessel as it was here for the Box was so fitted to the Barrel and by imbibing the Water notwithstanding the Oyl so swell'd that after the Ice was Thawed and the Water poured out at the touch-hole we were not able to pull it out with a pair of Pincers or a Vice so that we were forced to burn it out The Third Experiment BEing sensible of the many Difficulties we encountered in endeavouring to gain these Proportions by the Height of the Cilinders upon the same Basis and a Metalline Tube we betook our selves to the other Experiment of weight this we tryed with a Transparent glass Cane and Weighed the Water put therein to freeze and afterwards as much Ice as filled that same space in the Cane in a pair of Scales that turned with the 1 48 part of a Grane and the Proportion was found to be as 25 to 28 1 19 little less than that observed in the First Experiment of measure which was as 8 to 9 the same as 25 to 28 â…› finding so great an agreement in the proportions not to flatter our selves with this success we repeated the First Experiment with the same Cane and found it as at first as 8 to 9 and we were satisfied that the weight was not altered for keeping the Glass Cane close shut the whole time of the freezing and till it Thawed again our Balance shewed it to be of the very same weight as at first Experiments Touching the Procedure of Artificial Freezings with their wonderful Accidents THe first Vessel we made use of in these Experiments was a Bolt-head of Glass about 2 8 10 Inches Diameter with a Neck about 34 Inches long slender and divided into Minute Degrees into this we poured fair Water to a Sixth Part of the Neck then setting the Bolt-head or Ball in the freezing Mixture as we used to do to freeze Liquors we attentively observed the Motion thereof by viewing its Superficies we knew before as indeed few are ignorant of That from the first Application of Cold it contracts all Liquors lessening their Bulk and this we found true not onely in the Aqua vitae of the Thermometers but also we had often made the Experiment with fair Water Oyl Mercury and many other Fluids on the other side we had taken notice That the Water passing from a Simple Coldness to lose its Fluidity and receive consistency and firmness by Glaciation does not onely return to its first Bulk but so far Exceed it as to burst Vessels of Glass and Metal with great violence But we were yet ignorant what Period these several alterations produced by cold observed neither was it possible for us to attain it in Opake Vessels as those of Silver Brass and Gold were hitherto made use of in the Freezings wherefore not to fail in this which seemed to be the very Life of all these Experiments we had recourse to Vessels of Cristal and Glass hoping by the Transparency of the materials to be satisfied in the procedure of the Experiment since upon every Motion of the Level in the Neck we might take the Vessel out of the mixture and mark the correspondent alteration therein But the truth is we found greater trouble than at first we imagined to gain any certainty as to the Periods of these Accidents But to relate the success more distinctly you must know That upon the first immersion of the Ball as soon as ever it touch'd the freezing Mixture we observed in the Water in the Neck a little rising but very quick which soon subsiding it fell in the Neck with a Motion regular enough and a moderate Velocity retiring to the Ball till arriving at a certain degree it stop'd for some time as far as our Eyes could judge immovable Then by little and little it emounted but with a very slow Motion and apparently equal and then of a sudden without any proportionate acceleration it flew up with a furious Spring at which time it was impossible to follow it any longer with the Eye instantaneously running through the Decades of Degrees And as this fury began of a sudden so of a sudden it ceased changing from that great swiftness to a movement though very fast yet incomparably less swift than the precedent and with this it continued to rise most commonly till it ran over the Top of the Neck and all the while these things happened were observed several little corpuscles of air or some other more subtil Body to arise and pass through the Water sometimes in a greater sometimes in a less Proportion this separation was not visible till the Water began to receive an intense Degree of cold as if the force of the Cold had the faculty of secreting such a matter from the Water After this we were willing to see if these Alterations kept any kind of equality or proportion with each other wherefore we repeated the freezings scarce one Ice being dissolved but we set it again to freeze but the Water always froze with the same Series of Changes yet because they did not still every time rise to the same Marks or Degrees in the Neck we began to imagine there was no fixt Period for which it seemed we had some reason At last it happened that in often repeating these Experiments we by chance let the Water in the Bolt-head freeze in the Neck first of which we spake in the Fourth Experiment of freezing and so brake our Vessel Whereupon we were forced to make another this we blew less than the former that the cold might soon Insinuate it self through all the Water we also made the Neck longer to the height of 45 â— 10 Inches that it should not run over This we filled to 160 deg and set it to freeze in Ice very diligently heeding it we found at first that all the accidents of subsiding rising resting remounting swiftly running up and stopping again were the very same i. e. happened always when the Level of the Water was at the same Mark or Degree in the Neck for upon putting it in the Ice we observed it was reduced to the same Degree as in the former Tryal that is to say at the same Temperament of Heat and Cold taking the whole Instrument for a nice Thermometer by reason of the largeness of the Ball and proportion of the Neck being satisfied so far we proceeded to find the exact time of freezing and to obtain this we took the Ball out
of the Mixture often yet as often as we tryed it we were never so successful as to find the first small Veins or stiriae of Ice but it was either all Fluid or all over Frozen whence it was easie to gather that the Act of Glaciation must be very quick and whoever should happen to take it out of the Mixture in the very instant that the Water begins its swift carâ—ere might certainly observe some Notable alteration therein and because we had so often taken out and immersed the Ball into the Mixture we were not well assured of the Point of its Change we let it stand therefore and be reduced to its first Mark and placed it again in the mixture and took notice of the Degrees whereat it began to mount so swiftly and half a Degree before it came to it we took it out and very needfully regarding it with the Eye the Water in the Ball through the Transparency of the Vessel was easily discerned to be yet all Fluid but the before received Impression of cold still acting though it was now taken out of the Ice when it was just arrived at the Point with a swiftness indiscernable by the Eye and therefore scarce to be conceived forced the Water through the Neck and in an instant took away all Transparency from the Ball and changed its Fluidity into Ice There was no reason to doubt of its being wholly converted into Ice and that it was not onely outwardly crusted over because in Thawing it loosened first from the sides of the Glass lessening by degrees till at last it was like a small Lens of Ice which was in the End Dissolved We were well satisfied by often repeating the Experiment that it was just as we have related it and that we were not imposed upon Tab. 14. p. 81. We were after this very desirous to see the Order and Method observed by divers Liquors in freezings which for brevity are set down in the following Tables wherein STATE NATURAL signifies the Degree whereat the Water or other Fluid stood before Glaciation in the Neck of the Vessel RISE UPON IMMERSION is the first Leap made by the Water upon the Balls first touching the freezing Mixture This as the following Experiments will more clearly shew proceeded not from any Intrinsic Alteration of the Fluid but from the Extrinsic cause of the Vessel whence it is that varying sometimes a little it Communicated some variety to the other Changes through which the Liquor passed in freezing but whereas this is it self but small its variety is also but little and what it communicates to the subsequent Changes very inconsiderable ABATEMENT or Fall denotes the Degree to which the Water is reduced after the Rice upon Immersion when it just begins to receive the Impression of Cold. REST. Is the Degree whereat the Water stands for some time after its fall without any apparent Motion REMOUNTING shews likewise the Degree to which the Water is raised from its lowest fall by means of Rarifaction with a very slow and seemingly equal Motion altogether like the first wherewith it subsided SPRING UPON GLACIATION signifies the Degree to which the Water rises with that extream Velocity upon the very point of Glaciation We said before that after this Spring or Start the Water does not stop upon a sudden but continues to rise with a Motion swift enough though incomparably less than the preceding but of this Subsequent Motion we have taken no account it proceeding onely from the Prosecution of Rarifaction in the Ice already made or to say better from the Ice shooting in the Ball by little and little as it hardens after the fury of the first Impetus This we call the first shooting of Ice which is as we have found upon breaking the Balls from a very tender and weak beginning and like Sherbet when it is a little too hard being of no closer a Consistence than the first coagulations of Liquors Moreover it happens that this way of Freezing shews not the utmost Rarefaction of Fluids violently frozen it being impossible without bursting our Instrument to reduce the Ice to a perfect Solidity We have likewise to shew our utmost diligence and exactness made use of a Thermometer and Pendulum in each Experiment of freezing that with the Thermometer we might see at what Degree of cold and with the Pendulum at what time every change happened to the Liquors wherefore in the same Box with the Ball or Bolt-head we put a Thermometer of 400 deg but indeed we found great inconveniencies both in Noting the Degrees of cold shewn by the Thermometer and the spaces of Time given by the Vibrations of the Pendulum so that we must confess all our diligence was fruitless through the difficulty and impracticableness of applying an equal Proportion of cold to the Ball and to the Thermometer by reason of the inequality of the Pieces of Ice and quantity of Salt sprinkled And the cause is That in Artificial Freezing we make use of Snow or Ice which though ever so well bruised and as it were ground to powder yet upon mixing it with the Salt they become one Solid Mass and as hard as Stone so that it is impossible to close it round about the Vessel or be assured that it touches every where alike yet rather than be deficient we have set both down in our Tables that is the Degrees of the Thermometer and the Vibrations of the Pendulum leaving it to the discretion of the Reader to make a due Estimation of such Remarques The First Freezing Of Spring Water  The Deg. of the Vessel Differ Deg. of Therm Differ Vibrat Diff. State Natural 142  139    Rice upon Immer 143 ½ 1 ½ 133 6 23 23 Abatement 120 23 ½ 69 64 255 232 Rest 120  49 20 330 75 Remounting 130 10 33 16 462 132 Spring upon Glaciat 166 36 33    Note That 65 of the Vibrations of the Pendulum set down in this and the Four following Tables made one Minute The Second Freezing Of the same Spring Water  Deg. of Vessel Diff. Deg. of Therm Diff. Vibrat Diff. State Natural 144  141 ½    Rice upon Immers 146 ½ 2 ½ 118 23 ½ 25 25 Abatement 119 ½ 27 38 80 280 255 Rest 199 ½  28 10 415 135 Remounting 131 11 ½ 17 11 882 467 Spring upon Glaciat 170 39 17    The Third Freezing Of the same Deg. of Vessel Diff. Deg. of Therm Diff. Vibrat Diff. State Natural 143  141 ½    Rice upon Immersion 145 2 125 16 ½ 23 23 Abatement 119 ½ 25 ½ 51 74 369 346 Rest 119 ½  44 7 565 196 Remounting 129 ½ 10 38 6 933 368 Spring upon Glaciat 169 39 ½ 38    From these Three Examples of Freezing the same Water may be observed That the state Natural of the Water was not all
thicker and broader at one end and more acute at the other like little Daggers from the sides of these shoot out other small Threads close together like feathers or Palm branches these are as it were the first warping and with a confused and disorderly filling up they proceed shooting and increasing till the Woofe closes all with a total freezing of the Water the Superficies whereof may be perceived to be all raz'd and full of strait Lines like Cristal scratcht with a fine Graver At first the Superficies of all these Ices appears plain but when the freezing is throughly finish'd and all the Water Congealed it at last becomes raised in hillocks but without any regular Figure This Effect made some call to mind what was Registred in our first Experiment of Artificial Freezing where the innermost Cover of the Silver Vessel was found crack'd and all Coated over with a thin Ice made of the water that got out of the Vessel at the crack in the instant of freezing thereupon they said that the first Crust of Ice which spreads it self over the Superficies of the Water and shuts it closer than any Cover can by sticking fast to the sides of the Vessel does not leave space enough for the Water under it to rarifie in as it freezes but it is forced to seek room where it can and finding the Cake of Ice weaker than the sides of the Vessel it makes its way there and heaps it self up more in one place than another according to the inclination of the plains in which it breaks when the first Cake splits which afterwards likewise freezing forms that little swelling mentioned this happens sometimes to break the Vessels which as they think is most probably caused by the slowness of the Waters freezing at the bottom whereby the Cake of Ice at the top becomes so hard that it is easier to break the sides of the Vessels than the Icey Cover but no certain Rule can be given concerning these matters since there may be many cases wherein either the Vessel is onely burst or the Cover onely or first one then the other or both at the same time according as the External accidents of the Air vary as to cold calmness or winds and from the inequality of the Vessels Resistance or from the Nature of the Liquors themselves Before we put an End to this Discourse it will not be amiss to Relate a trifling Accident observed this year which though of small Moment may nevertheless be some help to the former Opinion A cup of Water being exposed to the Air in the Evening we found in the Morning all the Water frozen and in the highest part of its Superficies it had a Point of Ice a Finger high like a small sharp splinter of Rock Cristal This in all likelihood was no other than the Water issuing out at a crack in the first incrustation being forced by the freezing underneath which violently rising in a small stream and predispos'd to Freeze by the Cold of the external Air was congealed to an hard Ice in that very instant not having time to fall The Second Experiment Of the Freezing of Water in Vacuo WE have likewise tryed to Freeze Water in a Vacuum made with Mercury and that we might compare it with that made in the Air we put Water in a Vessel like that included in the Vacuum Therefore exposing them all Night we found in the Morning both frozen yet with this Difference that the Ice made in Vacuo seemed more equal and hard and less transparent and porous than the other and upon Examination was heavier in specie The way we took to discover this was by turning a piece of each Ice like a Cilinder and of the same bulk as near as we could and putting them in Spirit of Wine upon which gently pouring some Red Wine we saw the Ice made in the Air rise up before that made in Vacuo and when upon the top of the Water it swam about lighter and quicker because the Fluid covered less of it than of the other The Third Experiment Of the Freezing of Still'd Water HAving set common Still'd Water in several Vials to freeze we found the Ice more limpid and transparent than usually the water is onely in the midst there was as much as a small Nut of a more opaque Ice and whiter than the rest and round about it divers spiculae of the same kind of Ice in fine to give a true Picture of it in each Vial 't was like the Burre or Husk of a Chestnut frozen in a piece of Rock-Cristal as we see Flys Worms or Butter-flys entombed in Amber or like little bits of Straw Herbs c. in Cristal it self The Fourth Experiment Of the Freezing of Sea Water TO see the Freezing of Sea water we exposed one Evening to the Air when a Thermometer of 50 deg stood at 9 ° two Glasses full of it to freeze in an hour we found the shallowest began to freeze but in a manner somewhat different from common Water for it shewed like a great many small scales of Talke broken to pieces and put in Water These took away the Trasparency of the Water and gave it the consistence of Sherbet which is drank frozen in the Summer when the Externally applyed Snow growing more Languid it begins to dissolve In a while looking upon it again we observed it a little firmer as the Multiplying of the Scales lessened the Fluidity of the water in the morning it was yet harder tho it came nothing near the hardness of common Ice for upon any little agitation it turned to water the Figure of the Scales was narrow and longish and between them it was for the most part Fluid moreover the Mass stuck no where to the sides of the Vessel but turned freely about in it The Superficies was altogether plain without any prominences or Risings And the Difference consisted wholly in a more loose and thin Order and Texture then that of ordinary Ice The Fifth Experiment Of the Efficacy of Sal-Armoniac Nitre c. in Freezing IT is well known that Ice is most efficaciously cold when sprinkled over with Salt As to this we have observed That Sal-Armoniac invigorates it more than any other for we have experimented it upon the same water of the same Temperament and in like Vessels of the same figure capacity and thinness equally encompassed with the like quantity of beaten ice and the one being sprinkled with Sal-Armoniac the other with the same proportion of Nitre they were not frozen in the same space of time for a Thermometer of 100 deg being when it stood at 20 deg Immersed in Water set to freeze with Nitre subsided but to 7 ½ deg when at the same time a like Thermometer put in Water encompassed with the mixture of Sal-Armoniac fell down to 5 deg and the Water began to be skinned over We have already said upon another accompt That not onely Salt but strong-Waters
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
with Ice and then set it to freeze it was cooled first lest if it had been put into the Vessel at all rarefied by Heat upon the first Refrigerating it should Contract and by that means gain room to Dilate in afterwards in freezing When 't was thought the Ice outwardly applyed had done its work we took the Vessel out and opening the first Cover which was Concave we found the second Cover crack'd and covered over with a thin cake of Ice caused by the Water forced thither by the Rarefying of that within the Vessel as it froze Neither can it be thought that this crack was caused rather by condensation of the water in freezing which being constrained by the violent force of the cold to withdraw it self into a less space for the avoiding a Vacuum gradually drew down the Cover as it retired 'till at last unable to stretch any farther it crack'd I say this is improbable for if so we should have found the Cover bent inwards whereas it was forced outwards and considerably raised from the flatness it had before as was also the Superficies of the Ice in the Vessel moreover the Edges of the Crack turned outwards whence we gather how great the Impetus must necessarily be that caused it and would have been much more considerable if a larger proportion of water had been congealed whereas breaking the first Cake we found almost all the Water Fluid Tab. 12. p. 72. The Second Experiment FInding that the force of freezing far surpassed the Resistance of this our First Instrument we thought of making a Ball of Cast Silver of the thickness of a Crown piece and of an Oval Figure to open in the middle with a screw and with a Top screwed on at the End of the Neck as in the Figure Then shutting this Vessel and screwing fast the middle screw with a Vice we filled it with Water at the Neck and screwed on the little Cover and set it in a mixture of Salt and Ice to Freeze and in a little while taking it out we found it perfectly sound and whole opening it in the middle we took out a shell of Ice but it was very tender and less Transparent than usual and perchance more dense and close for being put in Water it did not seem to buoy up so well but rather as all thought dived towards the bottom in the midst was a Cavity as big as a large Almond without the Shell This Experiment was repeated after by us with the same success The Third Experiment THere were some that wondered at this unexpected accident seeming at first view to contradict not onely the Opinion of Galileo but what is more to be inconsistent with it self seeing tho this Ice appeared Condensed and heavy in respect of that made by the cold of the air without any art yet it must necessarily be lighter than Water because it in some measure still swam thereon and so much the less could they satisfie themselves as they saw the vacuity always in the middle of the Water Congealed whence it seemed necessary to conclude That the Water which fluid sufficed to fill the Ball being frozen withdrew it self into so much a less space as the aforementioned vacuity from so manifest an inconvenience they were inclinable to think there must be some fallacy and therefore set themselves to observe very nicely the whole progress of the Experiment So taking the Vessel very often out of the freezing mixture and carefully viewing it on all sides they perceived an almost insensible boiling and bubling out at the middle Screw from time to time a manifest sign that the Water so great is the force of its rarefaction crept through the Spiral Passages of the Screw upon this the Screw being waxed and the Ball again filled it was set in the Ice and Salt to freeze and tho 't was many times taken out there was never observed any bubbling or any hissing heard as before but after the freezing was done upon taking it out of the mixture the Vessel was open on one side of the middle Screw the rarefying power of freezing being great enough to force the Screw The Experiment being often repeated had still the same Effect and being again tryed in a Ball of Brass with a Screw of twice as many threads as the silver one had it still shewed the same trick The Fourth Experiment TO avoid this inconvenience of the Screws we got some Balls made of glass half a finger thick and filling them with Water set them to freeze being first sealed at the Flame of a Candle The Effect was exactly the same as that of the first Vessel made of Plate for they all were diversly broken and split some had their Necks quite thrown off others through the unequal thickness of the glass or irregularity of their Figure were burst on one side others were Tab. 13. p. 75. crack'd all over And 't was observable that the Neck was generally broken off when the whole ball was covered in the mixture of Ice and Salt so that the Water in the Neck being of the least bulk 't was first frozen Solid there and by that means stop'd and forced the Ball for in the procedure of the freezing the remaining Water endeavouring every way and either finding the neck the weakest part or the Ice therein being as a Cone or Wedge to split it it still most easily brake through there which never happened when the upper part of the Ball was left uncovered with the freezing mixture How great the force of this Rarefaction was may be gathered from this that when the Necks were not turned downwards upon the Vessels bursting they flew off into the air five or six feet high throwing up a great deal of the Ice with which the Balls were covered The Fifth Experiment AT last we resolved to cast a Ball of Brass all of one piece about Two Crowns thick having but one Mouth at the foot thereof so made as to be very close shut with an exquisite Screw Then to take the Lump of Ice out whole we made a small crease round it where by putting it again in the Lare it might be cut in two in the midst which shewed a strange accident in the Water for this small inequality as little as it was made the Ball burst in that place Whereupon we made another Ball and without weakning it in any part set it to freeze but this was broken as all the other for we tryed it often in that place which the water found most defective The Sixth Experiment THE Last Experiment was made with a ball of fine Gold of the size represented in the Figure this having undergone many freezings without any visible crack caused at first no little wonder and some began to doubt whether or no the space requisite for the freezing by the Diminution of the Thickness of the Metal by the force of the Water and by reason of its softness might