ixe quand il se recouvre de plantes; et s'il s'y accumule de la _terre
vegetable_, c'est un signe bien evident que rien ne l'attaque plus: car
elle seroit la premiere emportee si quelque cause exterieure tendoit a
detruire le sol qui la porte."

The doctrine here laid down by our author consists in this; first, That
there is a genus of plants calculated to grow upon rocks or stones;
those hard bodies then decay, in decomposing themselves, and affording
sustenance to the plants which they sustain. Secondly, That by this
dissolution of those rocks, and the accumulation of those vegetable
bodies, there is soil prepared for the nurture and propagation of
another genus of plants, by which the surface of the earth, naturally
barren, is to be fertilised. It is also in this natural progress of
things that the solid parts of the globe come to be wasted in the
operations of the surface, and that lofty rocks are levelled, in
always tending to bring the uneven surface of the earth to a slope of
vegetating or fertile soil.

Here we are to distinguish carefully between the facts described by this
author, who has seen so much of nature, and the conclusion which
he would draw from his principles. The surface of most stones are
dissolved, or corroded by the air and moisture. This gives lodgement to
the roots of plants, which grow, die, and decay; and these are carried
away with the earthy parts of the solid stone, in order to form a
vegetable soil for larger plants, growing upon some bottom or resting
place to which that earth is carried. Here is so far the purpose of
rocks, to sustain a genus of plants which are contrived to live
upon that soil; and here is so far a purpose for certain plants, in
decomposing rocks to form a soil for other plants which have been made
upon a larger scale, and are adapted to the use of man, the ultimate in
the view of nature.

Our author concludes thus: (p. 37.) "Le tems ne fera qu'augmenter
l'epaisseur de la couche de _terre vegetable_ qui couvre les montagnes,
et qui les garantit ainsi de plus en plus de cette destruction a
laquelle on les croit exposes: les pluies en un mot, au lieu de les
degrader comme on se l'imagine y accumuleront leurs depots. Tel
est l'agent simple qu'employe si admirablement le Createur pour la
conservation de son ouvrage."

Such, indeed, is the admirable contrivance of the system, that, in the
works of nature, nothing shall be destroyed more than is necessary for
the prese