Difficiles nugæ, or, Observations touching the Torricellian experiment, and the various solutions of the same, especially touching the weight and elasticity of the air

CHAP. XVI.

Concerning the two Suppositions that are ne∣cessary to maintain this Solution, viz Natures abhorrence of vacuum, and the Attraction of tensible fluids, or other bo∣dies when under a tension.

THere are two Suppositions that are necessary to be proved, to render the Solution above given evident or probable. I. The exclusion of a vacuum or space in the Universe wholly empty of any Body. 2. That any Body, capa∣ble of tension, or rarifaction by tension, (such as are the Air and thin effluvia of Mercury) to be attractive upon the con∣tiguous Bodies, when actually under that tension.

1. As to the former of these, I need not much labour for it, upon two rea∣sons. 1. Because there have been large Tractates upon this Position, and to re∣peat them would be but actum agere. 2. Because the exclusion of the Gravita∣tion and Elasticity of the Air, invented or substituted by the modern Elaterists, doth necessarily conclude, that there can be no vacuum in Nature; for all those Experiments and Instances, which they produce to prove that Gravitation or E∣lasticity, and by which they go about to solve them, must (if those Solutions prove untrue, or ineffectual) of necessity maintain that ancient Peripatetical po∣sition, because they are uncapable of any other Solution. And in my judgment that Gravitation and Elasticity of the common Air is sifficiently convinced by what hath been before said touch∣ing it.

And when I meet with those Obje∣ctions that I find used by Learned men, namely how the Mercury or Water comes to know there will be a vacuum, if they do not leave their natural Gra∣vity,

and so ascend or remain suspended to supply it, and how those stupid inani∣mate Elements or Minerals come to un∣derstand, that Nature so much abhor∣reth a vacuum; are much of the same kind, as if a man should ask the Sun, if it move according to Ptolemy; or the Earth, if according to Copernicus it move; how they came to know that when they come to the Northern Tropick, they must move again to the Southern Tropick? or when it hath touched the Southern Tropick, it knows that it must come back to the Northern, and steer its course accordingly? Or as if a man should ask, how doth the Stone under∣stand that he must descend, when yet all the men in the world can never give any satisfactory reason for its mo∣tion to the Earth, more than to the Moon, but only Nature that is the prin∣cipium motus & quietis, or rather the God of Nature, whose standing and statumi∣nated Law Nature is, hath so order'd it, and ordered so in the best way for the use, beauty, and accommodation of the Universe. The plain truth of it is, the

very consideration of the many attempts that have been made to explicate the reason of the descent of heavy Bodies, is enough to let us see, that we tire our selves in vain to determine the clear reason of it, without resolving it into the statuminated Law of Nature: though the Stone and the Earth are ina∣nimate, or at leaft unreasonable Bodies, such kind of Objections therefore as these are fond and weak.

2. As to the second, namely the at∣traction of Bodies extended, whether by rarifaction or tension, especially of the Air, or this subtle matter that ariseth from the Mercury. This affection and effect is as natural as any thing in Na∣ture, as is truly observed by the learned Fabri, in primo tractatu physico, prop. 205, 206, 208. For a strict contiguity in all parts of several Bodies is a kind of con∣tinuity of the Universe and all its parts; neither can I imagine how those that are fond of the Epicurean hypothesis, can better maintain the cohesion of the parts of solid bodies, their atomi hamati being but fancies of what men never saw in them.

The Air is the common cement and connecter of the different parts of this in∣ferior world at lest, and strictly inter∣poseth between their fissures and inter∣stitia, to maintain a kind of common continuity between the different parts of the Universe, and makes it as it were one continued Body.

But to come to particular Instances, which shall not be laborious but familiar and common, to evince this cohesion of the parts of tensed or rarified Air, and the contraction that it makes upon con∣tiguous bodies, in its endeavour of re∣stitution to its natural state and consi∣stence.

1. The instance of Cupping-glasses, where the Air is highly rarified or eva∣cuated by the included burning Tow, and applied to the flesh, draws up the flesh strongly unto it, when by the ex∣tinction of the Tow the rarified Air con∣tracts it self to a narrow room, which can be no otherwise than by the cohe∣sion of the particles of Air to the skin, and driving it in to the Glass, while it contract, it self to a narrower

compass. And certainly they that tell us, that this is done by the pressure of the ambient Air upon the contiguous flesh, which thrusts it up into the Glass, either do not believe themselves while they say it, or are so transported with a love unto or ingagement for their belo∣ved hypothesis, of the prodigious gravi∣tation of the free Air, that they are con∣tent to say any thing in its behalf.

Qui amant ipsi sibi somnia fingunt.

Shottus (who while he wrote his mi∣rabilia hydraulica, was well satisfied with the Solution of the Torricellian Experi∣ment by the common Solution of fuga vacui) was indeed afterward, when he wrote his mirabilia Magdeburgica, con∣verted to the new Solution, being not willing it seems to be thought to see less in Nature than the new Tribe of Virtuosi that were concerned in that Engine. But for all that, this Instance of Cup∣ping-glasses was too hard for that new Solution, and were fairly fain to have recourse to the decantata fuga vacui, or else it must stand unsolved, and so must any else that means an impartial and

unpreingaged search into Nature.

2. If an empty Bladder be tied close about the neck, and fastned to the top of the Tube, Hermetically sealed in the Torricellian Experiment, upon the sub∣siding of the Mercury the Bladder will be expanded, not by the natural Elate∣ry of the little particle of included Air, but by the strong attraction of the tensed Air in the Tube, by the descent of the Mercury, whereof before.

3. The Instance given in the tenth Chapter, of the Tube heated, and ap∣pended to a Ballance, so as it touch the Water, the Water rising in the Tube, the Tube will be drawn down, which is only done by the adhesion of the two extremes of the inclosed rarified Air, the one Extreme laying hold upon the top of the cavity of the Tube, the other end laying hold of the Water, and drawing it up, and therewith necessarily drawing the Tube down, whilst the included Air is contracting if self to its natural and narrower dimensions.

And because the Experiment made by a wide-mouth'd Glass would yeild

some discoveries of this attraction by the rarified Air, which are not so visible in so narrow a Tube, I took a Beer-glass, as in the Figure 14, and suspended it by a Thrid to one Scale of the Ballance, and weighing it with a weight in the op∣posite Scale, and found it weight two Ounces and half; then, as we used when we were School-boyes, sticking up a Candle in a Bason, I let down the Glass over the Candle contiguous to the Superficies of the Water, the Can∣dle going out there was a portion of Water drawn up into the Glass, the Air upon the Candles going out, and the Glass drawn down into the Water, the included Air being under a cause of ra∣rifaction, namely by the heat of the Candle, and by the extinction of the Flame now gradually contracting it self, and thereby drawing up the Water to supply that place.

The water drawn up into the glass was about half an Inch; we marked exactly the weight that was required now to lift up this Glass and included water was an addition of 4 Ounces and ¼ ⅛ of an

Ounce; so that the whole weight that raised the Glass and Water inclosed, and severed it from the Water beneath, was six Ounces ½ ¼ ⅛ of an Ounce, and then, though not without reluctance, the Glass was raised out of the Water.

Then taking the exact quantity of other Water, equall to that formerly included in the Glass, (which was not difficult to do by the help of the remai∣ning Mark) we weighed it, and found it to weight exactly three Ounces and half, and a very few Grains.

So that the weight of the Glass and inclosed Water amounting to six Oun∣ces, there was requisite an addition of about half an Ounce to sever the Glass from the Superficies of the restagnant Water, which did apparently to the eye and touch adhere together, not∣withstanding the counterpoise of six Ounces, equal to the weight of the Glass and included Water.

And this half Ounce of additional weight was due purely to the adhesion of the glass, Air, & inclosed water to the Superficies of the restagnant Water.

1. It seems evident, that not only the Glass, but the Water included in it, gravitates upon the Scale, for the coun∣terpoise of six Ounces in the opposite Scale, equals the weight both of the Glass and Water inclosed in it, which could not be, unless both contributed to the aequipondium.

2. That it is impossible that the in∣cluded Water could gravitate upon the Scale, unless the rarified Air were con∣tiguous and cohering to the top of the Glass, and also to all the parts of it in∣cluded within the cavity of the Glass above the Superficies and whole body of the included Water, and also firmly adhered to the Superficies of the inclu∣ded Water, for they all make up but one common weight, and there must be a vinculum that must connect the Glass and the inclosed Water, and otherwise they could not gravitate together; so that the vinculum that binds the Water to the Glass is this funiculus (as Linus well calls it) of the rarified Air, as the Thrid is the vinculum that binds the Glass to the Scale: for otherwise the

Glass would be only raised, and leave the Water to subside into the vessel of restagnant Water, and would never hold an aequipondium to more than two Oun∣ces and a half, which was the just weight singly of the Glass.

But as for the fancy above mentioned, Chap. 10. that it is not the Glass and Water that make up the weight of six Ounces, but the Glass and the column of Air incumbent upon it, the vanity of that imagination is sufficiently convin∣ced in that Chapter.

3. That consequently, the included rarified Air thus fastning upon the ca∣vity of the Glass and the included Wa∣ter by a strict cohesion, according to the nature of tensed fluids, contracting it self as much as it can by its motion of restitution, draws up the Water in the vessel into the Glass, and raiseth it as high, 'till there be an aequilibrium be∣tween the pondus naturale deprimens of the Water, and the potentia sustinens of the Air, thus now contracting it self, and indeavouring its restitution to its just natural dimension.

4. As a specimen of this cohesion of the Air and Water included in the Glass, there is also a cohesion of the Limb of the Glass and the included Water unto the Superficies of the restagnant Water, which requires half an Ounce of weight to break that continuity between the upper and lower Water. And no other imaginable cause can be assigned for it, but that Natura aegrè patitur disjunctio∣nem partium continui.

And as with the hand you lift up the Glass towards the Superficies of the re∣stagnant Water, the Water included will rise with it much above the Super∣ficies of the external Water, which can∣not be by the imaginary pressure of the external Air, but by the adhesion of the column of Water to the included ten∣sed Air, and of that to the concave Su∣perficies of the Glass per modum unius con∣tinui, which any man's tryal will make more plain and evident to him, than words in writing can easily express.

But some exception is taken to the word funiculus, and we are asked what Grappers there are belonging to this fu∣niculus,

that can so steadily lay hold of the Water and the Glass, and hold them thus tight togher?

And I must confess, that I wonder, that any that approves the Atomical or Epicurean Philosophy, can make that Question, since all their pretence of the cohesion of the imaginary Atomical Particles in any the most solid continu∣um, are certain atomi hamati, that in∣terlock one in another, which yet they never saw.

But let it be: I answer, the power of the laws of Nature are so efficacious, that they can and do colligate strictly parts even of most distantial textures and consistences, without the help of Vellicle, Hooks, or Grappers. What are the Hooks or Grappers, whereby the Humane Soul and Body, yea the Souls and Bodies of Animals are knit together, whereby the Bloud and the Spirits are colligated, whereby the Load∣stone attracts the Iron, notwithstanding an interposed Plate of Brass or body of impervious Glass, and a thousand more Instances of Attraction between Bodies,

without the intervention of sensible Grappers and Hooks, or such gross Mechanismes.

This, and some other as light as this, and some toying with the word funicu∣lus, are the greatest Objections that I find against what Linus hath in this matter delivered, which seem to me of no moment. Words were made to ren∣der Conceptions of things, and if they do that, they do their office.

And thus far concerning the Soluti∣on of the Torricellian Engin. I shall adde a few words, as I promised, touching the cohesion of two polished Marbles, and the insufficiency of the Solution thereof given by the Elaterists, and the truth of the ancient Solution thereof.