The fertility of the earth has been continued from the creation, through every successive period, to the present time. Plants spring up, grow, flourish, ripen their fruit, wither, and at last, having finished their course, die, and return to the dust again, from whence they first took their rise. Thus black mould, which covers the earth, is generally owing to dead vegetables. For all roots descend into the sand by their branches, and after a plant has lost its stem, the root remains; but this too rots at last, and changes into mould. Thus this kind of earth is mixed with sand, by the arrangement of nature, nearly in the same way as dung thrown on fields is wrought into the earth by the industry of the husbandman. But the earth offers again to plants from its bosom what it has thus received. For when seeds are committed to the earth, they draw to themselves, accommodate to their nature, and turn into plants, the more subtile parts of this mould by the co-operation of the sun, air, and rain; so that the tallest tree is, properly speaking, nothing but mould wonderfully compounded with air and water, and modified by a virtue communicated to a small seed by the Creator. From these plants, when they die, just the same kind of mould is formed as gave birth to them originally; whence fertility remains continually uninterrupted. Whereas the earth could not make good its annual consumption, unless it were constantly recruited by new supplies. That the Author of nature had so constituted the world that none of the elements should be subject to destruction, might have been supposed by the ancients; but, till the present advanced state of the science of chemistry, no proof of this interesting fact could have been adduced. Of the indestructibility of matter it may be remarked, that provision has been made even for the restoration of the fallen leaves of vegetables, which rot on the ground, and, to a careless observer, would appear to be lost for ever. Berthollet has shown by experiment, that, whenever the soil becomes charged with such matter, the oxygen of the atmosphere combines with it, and converts it into carbonic acid gas. The consequence of this is, that this same carbon in process of time is absorbed by a new race of vegetables, which it clothes with a new foliage, and which is itself destined to undergo similar putrefaction and renovation to the end of time.