But it is more particularly in the vast Southern Ocean that these works are prosecuted on a grand scale by the polypes of the lime, the corallines, and madrepores of every kind; an animal vegetation worthy of comparison with the labour of the mosses in a peat-moor, which continue to flourish in their upper growth while the lower are transformed and decomposed. Exactly like these vegetables, the polypes, and even their production, the coral, while still soft and tender, frequently become the nourishment of worms and fishes which feed and browse upon them like our cattle, derive their sustenance from them, and return them in the shape of chalk, without the slightest indication of a previous existence! Recently English seamen have discovered at the bottom of the sea this manufacture of chalk, which is incessantly passing from the living into the inorganic condition. But these destructive causes do not prevent the polypes from imperturbably carrying on their gigantic labours, incessantly elevating the islands and solid barriers which are so skilfully adapted to resist the oceanic action. They divide the work among themselves according to their species. The idlest execute their share in the quiet waters, or in the great depths, remotest from the light; others, under the sunshine, among the very breakers of which they eventually become the masters. Soft, gelatinous, elastic, adhering to their support, the stony and porous mass; they deaden the fury of the boiling waters which would wear out the granite, and split the rock into fragments. Under the mild trade-winds which prevail in the tropic climates, the sea would uniformly flow with a tranquil tide if it did not encounter these living ramparts, which force it back upon itself, scatter its waves in spray, and vex it with everlasting torment. That the waters should assault them is their fate. But they inflict no injury upon them; and in truth it is on their behalf they toil. Their violence does not wear _them_, but it wears the reef, and detaches in atoms the lime on which they live and with which they build. This lime, absorbed by them and _animalized_, changes into a hundred sparkling, living, active flowers, which are identical with our polypes, and form quite an analogous world enamelling the ocean-bed. On the margin of these islands,--which are generally circular, like a ring,--accumulates a layer of vegetable wealth, which speedily grows green, and embellishes itself with the only tree that can endure salt-water, the cocoa-nut palm. This, then, is the _humus_; the life which will for ever continue to develop. The fresh springs and fountains will next make their appearance, invited and fed by the vegetation. [Illustration]