There are two kinds of migrations, the voluntary and the unexpected. The former are out of the question in very early times. The latter are more possible, and more probable too, among shiftless and unprepared savages than among civilised nations. A family huddled together on a drifting raft, a few unfortunate people surprised by an inrush of the sea, clinging to trunks of trees, and caught up by the currents—these are enough to account for a transplantation over long distances. The weaker man is, the more is he the sport of inorganic forces. The less experience he has, the more slavishly does he respond to accidents which he can neither foresee nor avoid. There are striking examples of the ease with which men can be carried, in spite of themselves, over considerable distances. Thus, we hear that in 1696 two large canoes from Ancorso, containing about thirty savages, men and women, were caught in a storm, and after drifting aimlessly some time, finally arrived at Samal, one of the Philippine Islands, three hundred leagues from their starting-point. Again, four natives of Ulea were carried out to sea in a canoe by a sudden squall. They drifted about for eight months, and reached at last one of the Radack Islands, at the eastern end of the Caroline Archipelago, after an involuntary voyage of 550 leagues. These unfortunate men lived solely on fish, and carefully collected every drop of rain they could. When rain failed them, they dived into the depths of the sea and drank the water there, which, they say, is less salt. Naturally, when they reached Radack, the travellers were in a deplorable state; but they soon rallied, and were eventually restored to health.[90] These two examples are a sufficient witness for the rapid diffusion of human groups in very different regions, and under the most varied local conditions. If further proofs were required, we might mention the ease with which insects, plants, and testaceans are carried all over the world; it is, of course, unnecessary to show that what happens to such things may, a fortiori, happen more easily to man.[91] The land-testaceans are thrown into the sea by the destruction of the cliffs, and are then carried to distant shores by means of currents. Zoophytes attach themselves to the shells of molluscs or let their tentacles float on the surface of the sea, and so are driven along by the wind to form distant colonies. The very trees of unknown species, the very sculptured planks, the last of a long line, which were cast up on the Canaries in the fifteenth century, and by providing a text for the meditations of Christopher Columbus paved the way for the discovery of the New World—even these probably carried on their surface the eggs of insects; and these eggs were hatched, by the heat engendered by new sap, far from their place of origin and the land where lived the others of their kind.