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COnsidering that the greatest Part of the Universe, is made of Fluid Bodies, especi∣ally if according to the Cartesian Hypothesis, the Sun and fixt Stars consist of Fluids, it may not be amiss to illustrate, what we have only hin∣ted at in the foregoing Chapter: For the follow∣ing Experiments made about the superficial Fi∣gures
of Fluid Bodies, may not a little contri∣bute to illustrate, as well what hath been be∣fore delivered, as what hath been said concer∣ning the Pores of Fluid Bodies; besides, they may be of no small use, in accounting for seve∣ral Phaenomena belonging to the Grand System of the World.
* 1.1To try whether the concave Surface of Fluids, contained in a Pipe, was wholly to be attri∣buted to the Pressure of the Contiguous Air, I poured Dephlegmed Spirit of Wine upon a strong Alkalizate Menstrum, which was made of fixed Nitre run per deliquium in a moist Cel∣ler, and contained in a Cylinder of Glass of a∣bout a quarter of an Inch Diameter; I found that the Menstrum changed it's concave for a horizontal Superficies; and the like succeeded in a Glass of a much greater Diameter. And that Superficial Cavity was likewise almost destroyed by pouring on Oyl of Turpentine instead of Spi∣rit of Wine.
* 1.2If instead of the former Liquor, common Water was put into the Glass Cylinder, it retain∣ed it's former Surface, tho' Oyl of Turpentine Swam upon it instead of Spirit of Wine.
To try what Surface would be made by an
Oyl heavier than Water,* 1.3 by being contiguous to it, I put pure Oyl of Turpentine into a Glass Cylinder, and found that the Concave Superficies which it had whilst the Air was Contiguous, became Convex and protuberant upon an Affu∣sion of Water.
* 1.4Again having put Salt of Tartar deliquated in∣to a Glass Cylinder, and poured Oyl of Guajacum upon it, we found, that the Concave Superfi∣cies was not altred as it was by Oyl of Turpen∣tine: And having gently poured Water upon these two, the Oyl of Guajacum Swam betwixt the Water and the Oyl of Tartar, having a Convex Superficies at each end, that next the Oyl of Tartar being most protuberant.
* 1.5Having likewise put Oyl of Cloves into a Glass Cylinder; by pouring Water upon it, it's Concave Superficies presently became Con∣vex; and this Oyl being too heavy to Swim upon Water, we poured some of it upon Deli∣quated Salt of Tartar, pouring upon it likewise a little common Water, which being done we found the Oyl Protuberant at both Ends, but more at that which was Contiguous to the Wa∣ter.
Again, having put a considerable Quantity
of Quicksilver into a Pipe of the same Diameter,* 1.6 but much longer than the former; we found, that the Superficies of it, which was otherwise considerably Protuberant, was in some measure Depress'd, when Water instead of Air was Contiguous to it.
* 1.7Upon tryal, whether a greater or less Quantity of Water would alter the Surface of the Mercury, I found that the greater the Quantity of Water was, the more it was de∣pressed; tho' it did not always succeed: But when the Cylinder, being of a considerable length, was filled with Water, the Mercury Contiguous to the Glass was depressed to a Le∣vel; having, in the Center of its Superficies, a Protuberance Semicircular and raised above the other level Surface half it's Diameter, which Protuberance gradually subsided as the Mercury was drawn off.
* 1.8Having conveighed two of the afore-men∣tioned Cylinders, one containing Water, and the other Mercury into our Pneumatical Recei∣ver, we found that, notwithstanding the Air was not Contiguous, the Superficies of the Wa∣ter was not manifestly altred by the Exsuction of the Air, tho' the Mercury seemed some∣times to be a little more Protuberant, especially when the Exhausted Air was let in with any Celerity. But one thing in the Mercury, which
was observable; was, that upon the Exsuction of the Air, several Bubbles seemed to rise in the Mercury, and how much those might con∣duce to the mentioned Phaenomenon, we leave others to try. Again, having conveighed ano∣ther Cylinder into our Receiver, which con∣tained an Oyl, whose Superficies, when Water was poured upon it, was Convex; we found, that upon the Exsuction of the Air, neither the Oyl lost it's Protuberant, nor the Water it's concave Superficies: From which Experiments it may appear, what Effects the Pure Aether would have upon such Bodies, were they re∣mov'd out of this Atmosphere.
Though the Figures of the Parts of scatter'd Fluids, and of condensed Vapours, be usually Globulous; yet those Observations being too Transient, to deduce from them the Figures of the Parts of Fluids, we tryed the following Experiment, that I might observe something more Remarkable: Having mixed Fixt Nitre, dissolved into a Liquor by running per deliquium, with exactly rectified Spirit of Wine, and found that, those two Liquors, tho' shaked together, would retain distinct Surfaces; I drop'd Oyl into the Spirits, which gradually subsided till it touched the Superficies of the Ni∣trous Liquor. The Phaenomena exhibited by this Experiment were the following.
* 1.10Having put a Mixture of two Oyls, one of which was drawn from Turpentine, into other Liquors, to try whether the Lighter Oyl would separate from the heavier, with which it was incorporated; I found, that tho' it answer'd not my Expectation; yet as the Quantity of either of the Oyls was prevalent, the Mixture would ei∣ther sink or swim, in the Liquors it was put into. And to the Phaenomena exhibited by Oyl of Tur∣pentine, it may be added, That when part of it is contiguous to the Liquors it is put into, and part adheres to the Glass, the Superficies contiguous to the Water is of Figures too va∣rious and extravagant to be described.
* 1.11It is to be noted, that when the Nitrous Li∣quor is very clear, it will, in the former Expe∣riments, be very difficult to discover where the Surfaces of the two Liquors are contiguous, they both appearing to be one and the same Mass, except some Dust swims upon the Nitrous Li∣quor, or the Rays of Light fall obliquely upon it.
Having pour'd a peculiar sort of Oyl upon a Deliquation of Nitre and Tartar, ting'd with Cochinele, I observ'd, that by holding the Mix∣ture in a certain Position, the plain Superficies not only variously refracted the Incident Beams of Light, so as to represent several vivid Reflections, but the plain Superficies appear'd almost as con∣vex, as that of Quick-silver; and it was fur∣ther to be observ'd, That it almost as strongly reflected the Rays of a Candle, as a Close Spe∣cular Body usually does; which Phaenomenon could not proceed from the Alkali altogether, but might partly from the Concurrent Action of the Oyl, which I observ'd to contribute to Re∣fraction, when mix'd with other Liquors; but I shall not here endeavour to determine, what was the Cause of the Foremention'd Phaenomena; but in order to it shall observe, First, that nei∣ther the Confining Plain, which separated these two Liquors, nor the Superficies of the Nitrous Liquor, was the Occasion of that Red Colour, which the Flame of the Candle acquir'd. Se∣condly, the Liquor being chafed, the uppermost would be turn'd into a Froth, consisting of Bo∣dies imperfectly Globular, which in a little time would form a rude Physical plain, the Upper Su∣perficies of which, would reflect the Rays of Light very briskly; and when the Parts of the Froth became a little finer, they would reflect the Rays of a Candle, so as to represent so many pieces of Silver polish'd, or a Copper Plate freshly immers'd in a Solution of Silver in Aqua fortis: To which Phaenomena a Third may be added, viz.
That the confining Surface of the aforemention'd Oyl upon Spirit of Wine, was not a little strongly reflective. Most of these Phaenomena before mention'd, were afforded, by making use of Oyl of Limons instead of the former, except that the Reflection was not so brisk.
* 1.12Having pour'd Oyl of Aniseeds dissolv'd by a Moderate Warmth, upon warm Water, con∣tain'd in a Viol, I found that the Upper Surface of the Oyl, as well as that of the Water was Con∣cave; tho' the Lower Superficies of it was very Protuberant and Convex; and when it had been remov'd for some time into a Cold place, so that the Oyl might be Coagulated, the Convex Su∣perficies of the Oyl was something less protube∣rant: So that it seem'd to resemble a Concavo-Convex-Glass made use of for Dioptrical Purposes.
It is not only observable in the former Li∣quor, that the Oyl caus'd a much more vivid Reflection, in a Fluid than Consistent Form; but it may be further noted, That even the Shi∣ning Reflection of Quick-silver, may be increas'd by the Addition of a Liquor: For if Distill'd Mercury be put into a Viol, and Petroleum be gently pour'd upon it, the Reflection will be sensibly increas'd by the Addition of that Li∣quor; but whether that Reflection proceeds from some Subtle Body included betwixt the Petrloeum and the Mercury, I shall not deter∣mine; only to make it probable, That were
there such a Body included it might much con∣tribute to such a Phaenomenon, I shall add, That I once saw a Transparent Body, which was sup∣pos'd to have a true Oriental Pearl in it; but upon the Breaking of it, that which was suppos'd to be a Pearl, was nothing but a Cavity containing a Substance, something grosser than Air: And I have a piece of Glass by me, which hath Air included in a Cavity of a Pear-like shape, which causes such a vivid Reflection, as to resemble a fair Pearl. And I am Master of a Small Stone, which look'd upon in one's Hand directly down, seems to be like Common Glass; but if the Beams of Light in another posture fall upon it obliquely, it appears to be a fine Opal, or Oriental Pearl.
* 1.13Having melted a Gummy Substance in a deep round wide-mouth'd Glass, and conveigh'd it into our Pneumatical Receiver; upon extra∣cting the Air, we found, that which was con∣tain'd in the Pores of the Gummy Substance, to rise in Bubbles, several of which settled at the Top, and others were detain'd in the Body of it, upon the Cooling of that Substance: Where it was to be observ'd, that those which were in∣cluded in the Gummy Substance, did not only cause a considerable Reflection, but also the Air was so rarify'd in them, that upon the intro-admission of external Air into the Receiver, those Bubbles, which were rais'd to the Top, and ad∣orned with Curious Colours, like those of a Rain∣bow, were presently broke:
* 1.14Tho' it is usually thought, That the Parts of Water are Spherical, in falling Rain; yet since Hail, which is nothing but Drops of Water froze, and often of a Figure different from Orbicular; to be further satisfy'd concerning their Figures, we conveigh'd several Portions of Water into Oyl of Cloves, and found, that one which was as big as a Pea, was so near an Orbicular Fi∣gure, as to approach an Elliptical one; and other Portions of Water, which were larger, were somewhat Elliptical, but rather more depress'd in the middle; and these Phaenomena were afford∣ed by those Portions of Water which were only contiguous to the Oyl and Air.
Having put Oyl of Turpentine upon Oyl of Cloves, which was contain'd in a Glass Cylinder; I observ'd, that Water being encompass'd be∣twixt these two Heterogeneous Bodies, the Sur∣face of the Oyl of Cloves was but a very little protuberant; And the lower Surface of the Oyl of Turpentine, was but moderately Convex.
* 1.15To try whether Fluid Bodies would retain their smooth Surfaces, when reduc'd to a Solid Form, I left Oyl of Aniseeds to coagulate upon Water, and found that that Superficies, which was Contiguous to the Air, as well as that which was next the Water, had each a peculiar kind of Roughness.
Having expos'd one Portion of Water to be froze, with Oyl of Junipers upon it, and another with Oyl of Turpentine; I found that the Ice, which was under each, had a different and pe∣culiar Surface: A Variety of Surfaces may like∣wise be observ'd upon several frozen Liquors, which abound with Water. And I have ob∣serv'd my self, in a red Decoction of Soot of Wood, set to freeze, Crystals shap'd like Daggers, curiously emboss'd, as well as fring'd at the ends.
And besides the Irregular Surfaces of a frozen Liquor, contiguous to a Heterogenous Body, I have observ'd in Oyl of Vitriol, that Part of it being froze, the Superficies, which was conti∣guous to the Liquid Part, was very unequal with several Asperities.
And not only Bodies, which are Naturally Fluid, but those brought to Fusion by Art, ac∣quire Various Sufaces upon their putting on of a Solid Form; For I have observ'd, upon the Sur∣face of a Regulus Martis Stellatus, and a Regu∣lus of Antimony without Mars, Curious Emboss∣ments of the Figure of a Star; but if to these Bo∣dies Copper be Artificially added, they acquire New Surfaces, sometimes resembling a Net: And I have now by me, a Mass of a Conical
Figure, consisting of two Parts, contiguous to each other, which when separated, the lower Part had upon it's upper Side, a great many Protuberances; and the Conical Part on it's Su∣perficies, which was contiguous to that, was furnish'd with Cavities answerable to, and adap∣ted to receive those Protuberances: Whence it might be inferr'd, That the more Metalline Part, which was emboss'd with those Protube∣tances, was first hardned, and the other more scorious and recrementitious Part, was after∣wards adapted in it's Coagulation to the Protu∣berances of that which would melt with the Heat of ones Hand, tho' the Metalline Ingredients be much more hard to be brought to Fusion than Lead, or even Silver it self; and we have some∣times obtain'd such a Vitriol, as might be pre∣serv'd in a fluid Form by the languid Heat of the Sun in Winter, either with Spirit of Nitre or a certain Aqua fortis: From whence it ap∣pears, that the Textures of Compositions are to be consider'd, as well as the particular Con∣sistence of the Ingredients.
The Figure of the Sur∣face of a Nitrous Li∣quor.
Of Water.
Of Oyl of Turpentine.
The Superfi∣cies of a So∣lution of Tartar, &c.
Of Oyl of Cloves.
Of Quick∣silver.
Of the same.
The Surface of Liquors in Vacuo Boyliano.
Phaenome∣na exhibi∣ted by a Ni∣trous Li∣quor and Spirit of Wine.
Of Oyl of Turpentine
Several Co∣lours exhi∣bited.
Of Oyl of Aniseeds.
An Expe∣riment in Vacuo Boy∣liano.
Of Water included in Oyl.
Of Coagu∣lated Oyl of Aniseeds.