clear and luminous atmosphere. The authors of the speculations, follow the first course; they who merely evade them by silence, follow the second course the third, is open to those who resolutely rise above them into the brightness of authenticated truth, and who are thus enabled to see and observe the whole circuit of the cloud in which the others remain involved1. The first of these, build their geological structures on a false foundation ; the second, build them on none-in the air; the third, will found them in an immoveable rock, whose solidity is susceptible of demonstration.

It will, therefore, be important to the prosecution of our inquiry into the MODE of primitive formations, to investigate preliminarily, with some minuteness, the ground of the opposition of doctrine between the philosophies of Newton and of the mineral geology, respecting a chaotic or fluid state of this globe; and to observe, how deeply the foundation of that opposition is laid.

When Newton had remarked, that the planets present to the sight figures of obtuse spheroids, and not of perfect spheres; when he had reflected upon the nature and properties of that peculiar figure, and had contemplated those orbs as subjected, in their

The Reviewer of D'Aubuisson's Traité de Géognosie in the Bibliotheque Universelle, passes over the first part of that work, deeming it, as it would appear, too speculative. Yet, its speculation is directed to one of the sublimest and most important objects that can engage the intellect, viz.— the MODE of primitive formations. That object, however, the Reviewer le s pass sub alto silentio; without an attempt to extricate himself from the cloud, in which it is manifest he feels himself involved.

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revolutions, to the adverse actions of gravity and centrifugal force; his penetrating mind at length discovered, that the rule of harmony and equilibrium between those two contending powers, was only to be found in the figure of an obtuse spheroid. To render this fact plain to the understanding of others, he imagined this hypothetical illustration." If," said he, "the earth were formed of an uniformly yielding "substance, and if it were to become deprived of its motion,―si terra constaret ex uniformi materia, motuque omni privaretur," the law of gravity, acting equally, and without resistance, from all points of its surface towards its centre, would cause that yielding substance to settle into the figure of a perfect sphere. But, if it were then to receive a transverse impulse which should cause it to revolve upon its axis, the new transverse force would counteract the former force of gravity, by urging the particles composing the yielding substance from their centre towards their circumference; and, would thus produce an alteration in the figure of the sphere. For, the new force would tend to elevate the surface, and would have most power at the equator and least at the poles; whereas, the opposite force of gravity would tend to depress the surface, and would have most power at the poles and least at the equator. The result of this inequality of gravitation, must necessarily be; that the original sphere becoming elevated at the equator, but

Princip. Math. lib. iii. prop. 19. prob. 3.

not at the poles, and the elevating power gradually diminishing from the equator to the poles, its figure would be eventually changed into that of an obtuse spheroid.

It being thus shewn, that such would be the necessary result of the compound power of gravity and centrifugal force; it followed, that those two antagonist forces, acting at the same time in the earth supposed to be formed of an homogeneous and, uniformly yielding substance, would work themselves into harmony and equilibrium by producing that figure; which they should thenceforward maintain. › Whereas, if we suppose the case of a true sphere, which should consist of a solid and resisting substance; the two forces must act in perpetual and violent discord and conflict, with a constant tendency to disunite and rend the texture of the fabric. Now, Newton, maintained, "that GOD at the beginning "formed all material things, (and therefore this "earth which is one of them,) of such figures and

properties as most conduced to the END for which "HE formed them," and, having demonstrated, that the property of an obtuse spheroid was that which most conduced to the END for which God formed the earth, he left it to the capacity of every one to draw the obvious inference, in conformity to his known principles,-viz. that it is highly probable, that God has formed the earth with the same figure which it is manifest He has given to the other planets, and for which an ADEQUATE REASON is thus rendered plain to the intelligence. And he confirmed

this argument of probability, by superadding the experimental proof, that, unless the earth was actually flatter at the poles than at the equator, the waters of the ocean, constantly rising towards the equator, must long since have deluged and overwhelmed the equatorial regions, and have deserted the polar; whereas, the waters are now retained in equilibrium over all its surface. Such was the whole nature, design, and extent, of Newton's proposition and demonstration. And, so his accurate expounder drew his inference: "What we have "said of a fluid earth, must hold of the earth as it "is; for, if it had not this figure in its solid parts, "but a spherical figure, the ocean would overflow "all the equatorial regions, and leave the polar regions elevated many miles above the level of the sea; whereas we find, that one is no more "elevated above the level of the ocean than the "other1." It did not enter into his head, any more than it did into Newton's, to draw from this demonstration the geological conclusion; that "our globe was once REALLY fluid."

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But, the illustration inspired the mineral geology with peculiar satisfaction. Without making any reference to the principles and conclusions of Newton's philosophy, or to the object for which alone he designed the illustration; it seized upon his hypothetical plastic sphere, and transformed his philosophical demonstration into a geological propo

1 MACLAURIN, Account of Sir Isaac Newton's Phil. p. 364.

sition. That supposed sphere, bore too convenient and desirable a resemblance to the "chaotic fluid" or "confused mixture of elements," not to be eagerly realised, and identified with it by the mineral geology; which imagined, that it could thus argue the original fluidity of the earth, and its consequent obtuseness, and appeal to the authority of the Principia Mathematica" for a Chaos.

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"The spherical figure of the earth (it said) had, for a long time, suggested the idea that its mass had been fluid, at least to a certain depth; "Newton, setting out from that idea-Newton, par"tant de cette idée-joined to the rotatory motion "of the globe, found that its diameter at the poles, "must be to its diameter at the equator, as 229 "to 230. Now, we find in the Philosophical "Transactions of the Royal Society of London, for the year 1791, a memoir by M. D'Albi, in which, discussing the sum of the results of the measure of a degree of the meridian in different

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latitudes, he finds that this determination of "Newton is confirmed by experiment, as far as "this latter method of determination could extend. "We thus, therefore, KNOW, that our globe REALLY

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WAS once liquid, at least to a certain depth; and, that when it acquired its solidity in the portion. "essential to its form, it had the same sensible velocity of rotation, which it has now1." And again: "The earth was covered with a liquid con

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1 DE LUC, Lett. Géol. p. 81.