The proof that the earth's primitive condition was like to a liquid or half paste, is, that if we take a plastic sphere, for instance a slightly fluid ball of quicksilver, and make it turn rapidly upon its axis, we observe that it swells out in the middle, and becomes flat at the two poles, or the extremities of the axis; this is the effect of the centrifugal force engendered by the rotatory motion. Now the earth is depressed at the poles, and slightly swelled out at the equator.
The other planets must have been formed by the same process as the earth. They were, no doubt, composed of a collection of gas and vapours, which became liquid, pasty, and eventually solid, by a process of refrigeration. This process, taking effect especially upon their surface, they began to put forth a skin, or exterior and solid covering, which was the soil of the planet. On this resisting soil fell the liquids resulting from the condensation of the water vapour, and thus the first seas of the planets were formed.
We would remind those who doubt the correctness of this theory that the poles of the globe of Saturn and that of Jupiter are much more flat than those of the Earth; which is explained by the greater velocity of the rotation of each upon its axis. Our days are 24 hours long, whereas those of Jupiter and Saturn are only 10 hours. Greater rapidity of rotation produces a correspondingly increased depression at the extremities of the axis. This geometrical result demonstrates the justice of the assimilation in their respective origin which we maintain between the Earth and the other planets.
In the warm waters of the basin of the seas the first living beings which existed upon our globe appeared. Animal life commenced in the waters, in the primitive forms of zoophytes and mollusca, as we know, because zoophytes and mollusca, with the addition of a few articulates, composed the animal remains found in the transition strata which come after the primary formations. The first vegetables are found in the same transition strata, they are mosses, algæ, and ferns.
When the earth had become somewhat cooler, phanerogamous vegetables appeared upon the continents. Numerous vegetable species were simultaneously created, for the flora of the secondary formations is extremely rich and varied.