This is not a very varied world. But wait. The winds and the currents are constantly at work to enrich it; come a good tempest, and all the neighboring isles will be laid under contribution to enrich this rising one. And in this is one of the most magnificent functions of the Tempest; the greater, the wilder, and the more sweeping, the more fecund it is. A water-spout passes over an island; the torrent that it produces carries with it slime, rubbish, plants, living or dead, and even whole forests, which the waves carry to the neighboring isles, raising, and at the same time enriching, their soil. A great messenger of life, and one of the most transportable, is the solid cocoanut. Not only does it travel well, but, when thrown upon shoal or rock, if it find only a little poor white sand, which would support nothing else, the cocoanut contents itself there, finds brackish water not a jot less agreeable than the freshest; germinates, thrives, grows into a robust cocoa tree. A tree being thus planted, fresh water comes, falling leaves create earth, other trees follow, and at length we see the noble palm grove, which arrests the vapors, which at length form a rivulet or river, which, flowing from the center of the isle, make an opening of fresh water in the cincture of white sand, and thus keep the polypes, inhabitants only of salt water, at a respectful distance. Of the rapidity with which the Polypes do their work, we have some curious proofs. In forty days' harboring at Rio Janeiro, boats were wholly destroyed; in a strait near Australia, there were formerly only twenty-six islets; there are already a hundred and fifty--well recognized: and the English admiralty believes that there are even more; and in twenty years hence the whole strait, forty leagues in length, will be so completely blocked up as to be unnavigable. The eastern shoal of Australia is three hundred and sixty leagues, (one hundred and twenty-seven without any interruption,) and that of New Caledonia one hundred and forty-five leagues; the single shoal of the Maldives is almost five hundred miles long, and groups of isles in the Pacific are four hundred leagues long, by a hundred and fifty wide. To all this work of the Polypes, we must add, that the banks of the isle of France, and the shallows of the Red Sea, are continually rising. Tunis and its environs present a wholly animal world; and the rocks present forms so strange, and colors so splendid, that the spectator is amazed and dazzled. You see them in a space of several leagues of shallow sea water--probably not averaging more than a foot of depth, working calmly, but perseveringly at their business of creating. Their first intelligent observer was Forster, companion of Cook, who found them at work, caught them in the very fact of their great conspiracy to make, noiselessly and marvellously, whole chains of islands, to be by degrees converted into a continent.