"of it. This weight acting as a mechanical power, "made the shorter arm of the first-mentioned lever

press down the cover of the box with a certain force, which, according to the general law of all mecha"nics, was to the twenty-eight pounds at the end of "the line, as the space moved through by the power, "to the spuce moved through in the same time by "the weight: but these spaces being compared with "cach other, I found that the greater was to the "lesser as eighty-two to one, so that if we multiply "twenty-eight by eighty-two, the product will be "two thousand two hundred and ninety-six pounds, "to which something must be added for the friction "of the machine, though I took what care I could "to render its motion as true and easy as possible. "While the cover of the box was pressed down by so great a weight, the water inclosed within it, was made to freeze; and the agent by which the water was congealed, did fairly overcome the "whole force of the machine.

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"Though this experiment succeeded so far as "to give me the satisfaction I wanted, it was interrupted by an accident I did not look for. "When the water began to freeze, and the cover of "the box to be raised up from the rim, I perceived "that the ground yielded under the pressure, and "that the flat stone which served as a basis to the pedestal, was sunk a little below its first position. By this means the force was at first spent upon the ground, and did not take place in the machine, "till the ground would no longer give way. It was, "however, so sensibly perceived in the machine "likewise, as to prove that this force was at least "superior to one ton two hundred and ninety-six pounds. How much greater it may prove to be, I cannot as yet affirm; though I believe my apparatus "would answer the purpose, if it were required "to pursue the experiment to the bottom. But there are so many circumstances to be nicely

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"attended to, in order to make it succeed, and so "much time and trouble to be bestowed upon it "out of doors in cold weather, that my patience was "wearied out, for this winter at least, by a single "attempt.

"The cavity of the box, as I find by gauging it, " contains five cubic inches and 6-10ths. Water "when it freezes commonly increases in its bulk, by "1-9th of the whole; therefore the space occupied "by the æther, which exerted all this force upon "the machine, was equal only to about 6-10ths of a "cubic inch. And hence it will appear by a "calculation, not worth particularizing, that the "force of this æther (even in this experiment, which "undoubtedly falls very short of the whole truth,) was about two hundred and seventy-three times "greater than the ordinary pressure of the atmosphere.

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"Mr. B. Robins, the engineer, found by several "accurate experiments, that the force of fired "gunpowder is about one thousand times greater "than the pressure of the atmosphere; and the "force of that agent which consolidates water into "ice, may be found equal to it, for aught that has "yet appeared to the contrary. We do not wonder "at the power of fire, when it acts with a vehement "degree of heat, although its effects are so great "that nothing can withstand it, as in gunpowder, "and in the engine for draining mines by the steam "of boiling water. But here we have the same "substance (for the water was perfectly cleared of "its air,) exerting a most astonishing force, even "when reduced to the temperature of ice; and we may judge from the phenomena of cohering bodies, "that this force will be greatest when the cold is "greatest."-Ibid: Postscript, p. 268.

PART II.

NEW SYSTEM, &c.

THE HE Primum Mobile contains the Machinery of Nature, in which every thing created has a part to act, either as primary, considered individually, or subordinate the whole being connected in that state of harmony apparent in all the works of the Creator. Notwithstanding the regularity these phenomena exhibit, the laws whereby they are governed, have baffled the researches of enquirers, who have generally disregarded truth and substituted sophistry in accounting for them, whereby they have disfigured the simplicity of Nature.

Modern philosophers appear generally to admit of a medium in space; and the doctrine of a vacuum seems to be nearly exploded. "The existence of "an universal connexion between all parts of the "sideral Heavens, is now generally admitted."Encyclopedia Londonensis: Vol 2, p. 400.

Some who still hold with this preposterous proposition, are possibly misled by supposing, though erroneously, that this was the confirmed opinion of Sir Isaac Newton, but which is evidently not the case; Sir Isaac Newton's first opinion on this doctrine, was founded on a mathematical calculation, according to which, he suspected the impossibility of a substantial medium, thinking that thereby bodies traversing in their orbits, would be obstructed and ultimately stopped; however, when he found that these operations could be performed in a substantial medium, he recanted his former doctrine of a vacuum, by allowing space to be filled with a substantial medium, as is evident in his opt. p. 323-325: "The æther which fills the Heavenly spaces, is a medium which pervades all

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"bodies, and its elastic force is expanded through "the whole Heavens, and that it may suffice to impel bodies from the denser parts of the medium "to the rarer, with all that force or impulse, which "we call Gravity." It is unnecessary to produce in this place any other proofs, as there will be several more in the work which will come more properly in their places, and prevent the necessity of repetition. That Sir Isaac Newton did maintain a contrary opinion, is proved by Pemberton, p. 166, under the head "that the planets move in a space empty of all sensible matter," and as the reasons are very particularly assigned for the support of this opinion, it seems proper to quote the whole to the end of the chapter; when it will be seen that mathematical calculation is the foundation on which these arguments are supported, and which this great man himself saw reason to relinquish.

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To shew that there is no sensible matter lodged in space, where the planets move, Pemberton proceeds thus: "That they suffer no sensible "resistance from any such matter, is evident from "the agreement between the observations of astro"nomers in different ages, with regard to the time, "in which the planets have been found to perform "their periods. But it was the opinion of Des "Cartes, that the planets might be kept in their "courses by the means of a fluid matter, which continually circulating round should carry the planets along with it. There is one appearance "that may seem to favour this opinion; which is, "that the Sun turns round its own axis the same "way as the planets move. The Earth also turns "round its axis, the same way as the Moon moves "round the Earth. And the planet Jupiter, turns

upon its axis, the same way as his satellites "revolve round him. It might therefore be sup"posed, that if the whole planetary region were "filled with a fluid matter, the Sun, by turning

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"round on its own axis, might communicate motion "first to that part of the fluid, which was contiguous, and by degrees propagate the like motion

to the parts more remote. After the same manner "the Earth might communicate motion to this fluid, "to a distance sufficient to carry round the Moon, "and Jupiter communicate the like to the distance "of its satellites. Sir Isaac Newton has parti"cularly examined what might be the result of such "a motion as this; Philos. princ. mathem. Lib. ii. prop. 2, and he finds, that the velocities, with "which the parts of this fluid will move in different "distances from the centre of the motion, will not 66 agree with the motion observed in different planets; "for instance, that the time of one entire circulation "of the fluid, wherein Jupiter should swim, would "bear a greater proportion to the time of one entire "circulation of the fluid, where the Earth is; than "the period of Jupiter bears to the period of the

Earth. But he also proves, that the planet cannot "circulate in such a fluid, so as to keep long in the "same course, unless the planet and the contiguous "fluid are of the same density, and the planet be "carried along with the same degree of motion, as "the fluid. There is also another remark made upon "this motion by our author; which is, that some "vivifying force will be continually necessary at the

center of the motion. The Sun in particular, by "communicating motion to the ambient fluid, will "lose from itself as much motion, as it imparts to "the fluid; unless some acting principle reside "in the Sun to renew its motion continually.

"If the fluid be infinite, this gradual loss of "motion would continue till the whole should stop; " and if the fluid were limited, this loss of motion "would continue, till there would remain no swifter "a revolution in the Sun, than in the utmost part of "the fluid; so that the whole would turn together "about the axis of the Sun, like one solid globe.