ᏢᎪᎡᎢ 1.

CHAP. III.

Till all things, to their end of growing brought,
Creative Nature in perfection wrought.

Newton emphatically, and as it were by a pro-
phetical judgment, pronounced this conclusion
of the mineral geology to be "unphilosophical;"
and therefore, essentially contrary to that which
alone he acknowledged to be philosophical,
according to the principles of his own philo-
sophy.

This judgment, indeed, chiefly affects the Neptunian system; but he has not altogether forgotten the Plutonian, which perpetually replaces a perishing system of the globe with a new one, by "the mere laws of nature:" "The growth of new systems out of old ones," says he," without the mediation of a DIVINE "POWER, seems to me apparently absurd1."

1 Third Letter to Dr. Bentley.

CHAPTER IV.

CHAP. IV.

Ir will be instructive and important, to PART I. trace with some minuteness the opposition of doctrine, between the philosophies of Newton and of the mineral geology, respecting a chaotic state of this globe; and to observe, how deeply the foundation of that opposition is laid.

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

PART I.

CHAP. IV.

1

"of its motion," si terra constaret ex uni-
"formi materia, motuque omni privaretur 1;”
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 im-
pulse, which should cause it to revolve upon
its axis, the new transverse force would coun-
teract 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 that 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 gravita-
tion must necessarily be, that the original sphere,
becoming elevated at the equator, but not at the
poles, and the elevating power gradually dimi- '
nishing from the equator to the poles, its figure
would be eventually changed into that of an
obtuse spheroid.

It being thus shown, that such would be PART I. the necessary result of the compound power of gravity and centrifugal force; it followed, CHAP. IV. that those two 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 would 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, and 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 thus 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 super

66

D

CHAP. IV.

PART I. adding 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

66

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 the earth had been REALLY fluid.

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

' MACLAURIN, Account of Sir Isaac Newton's Phil.

p. 364.