The same elements, the same principles, are found in the formation of minerals, as well as in their decomposition, whether natural or artificial. We find that earth, diversely modified, wrought, and combined, serves to increase their bulk, and give them more or less density and gravity. Air and water contribute to make their particles cohere; the igneous matter, or inflammable principle, tinges them with colour, and sometimes plainly indicates its presence, by the brilliant scintillation which motion elicits from them. These stones and metals, these bodies, so compact and solid, are disunited, are destroyed, by the agency of air, water, and fire; which the most ordinary analysis is sufficient to prove, as well as a multitude of experience, to which our eyes are the daily evidence. Animals, plants, and minerals, after a lapse of time, give back to Nature; that is to say, to the general mass of things, to the universal magazine, the elements, or principles, which they have borrowed: The earth retakes that portion of the body of which it formed the basis and the solidity; the air charges itself with these parts, that are, analogous to it, and with those particles which are light and subtle; water carries off that which is suitable to liquescency; fire, bursting its chains, disengages itself, and rushes into new combinations with other bodies. The elementary particles of the animal, being thus dissolved, disunited, and dispersed; assume new activity, and form new combinations: thus, they serve to nourish, to preserve, or destroy new beings; among others, plants, which arrived at their maturity, nourish and preserve new animals; these in their turn yielding to the same fate as the first. Such is the constant, the invariable course, of Nature; such is the eternal circle of mutation, which all that exists is obliged to describe. It is thus motion generates, preserves for a time, and successively, destroys, one part of the universe by the other; whilst the sum of existence remains eternally the same. Nature, by its combinations, produces suns, which place themselves in the centre of so many systems: she forms planets, which, by their peculiar essence, gravitate and describe their revolutions round these suns: by degrees the motion is changed altogether, and becomes eccentric: perhaps the day may arrive when these wondrous masses will disperse, of which man, in the short space of his existence, can only have a faint and transient glimpse.