The diameter of our globe, according to the best observation, is believed to be about 7970 English miles, and its circumference 25,038: consequently, if it were solid, it would contain 265,078,559,622 cubic miles of matter; while a globe of only half the diameter, would contain only 33,134,819,952.[3]
Suppose our globe divided into parts of one square mile on the surface, bounded by straight lines converging to a point at the centre, as the subjoined figure represents:
and then suppose there were no other particles of matter in the universe but A and B, A containing 1,328 cubic miles of matter, and B only 166, A would attract B so as to make their centre of attraction at O, which point would become at once the common centre: but admitting the whole matter of the globe to exist, A would still exert its influence on B, but both would be operated upon by T and S and the surrounding matter, all perhaps, tending to one common centre. However, I imagine that the tending to the centre would not be so great as is contended for by the generally received theory, which alleges that matter at the centre of the earth is four times as hard as hammered iron. The Newtonian philosophy appears to contemplate a globe at rest, and not in such rapid motion as we know the earth and other planetary bodies to be in, communicating to them a centrifugal force, which tends to throw matter from the centre. The rotary motion of each planet is no doubt regulated by the quantity of matter it contains: so that at its surface centrifugal and centripetal forces are equally balanced――the rotary motion being adequate to communicate a force to counter-balance the force of gravity.
Newton ascertained by his investigations of the properties and principles of matter, the earth to be a globe flattened at the poles: and the French philosophers afterwards confirmed this fact by measuring a degree in different latitudes. This difference between the equatorial and polar diameters of the earth, and of the other planets which are also known to be of that shape, is ascribed by those philosophers who attempt to account for such a formation, to the projectile force of the globe at the equator occasioned by its rotary motion. This is admitting that the matter of our globe was once in so soft a state as to take its form from motion; for were the earth a compact solid body, and four times as hard as hammered iron at the centre, (as the Newtonian system alleges) this rotary motion round an imaginary axis could never give to the globe the form of an oblate spheroid, as is ascertained to be the fact; because a hard solid body moving in empty space, could not be supposed to yield into that shape by any law of action as yet unfolded by science.
