anything can be inferred from these scanty facts, that the seeds of 14 / 100 kinds of plants of any country might be floated by sea-currents during twenty-eight days, and would retain their power of germination. In Johnston’s Physical Atlas, the average rate of the several Atlantic currents is thirty-three miles per diem (some currents running at the rate of sixty miles per diem); on this average, the seeds of 14 / 100 plants belonging to one country might be floated across 924 miles of sea to another country; and when stranded, if blown by an inland gale to a favourable spot, would germinate.
Subsequently to my experiments, M. Martens tried similar ones, but in a much better manner, for he placed the seeds in a box in the actual sea, so that they were alternately wet and exposed to the air like really floating plants. He tried ninety-eight seeds, mostly different from mine, but he chose many large fruits, and likewise seeds, from plants which live near the sea; and this would have favoured both the average length of their flotation and their resistance to the injurious action of the saltwater. On the other hand, he did not previously dry the plants or branches with the fruit; and this, as we have seen, would have caused some of them to have floated much longer. The result was that 18 / 98 of his seeds of different kinds floated for forty-two days, and were then capable of germination. But I do not doubt that plants exposed to the waves would float for a less time than those protected from violent movement as in our experiments. Therefore, it would perhaps be safer to assume that the seeds of about 10 / 100 plants of a flora, after having been dried, could be floated across a space of sea 900 miles in width, and would then germinate. The fact of the larger fruits often floating longer than the small, is interesting; as plants with large seeds or fruit which, as Alph. de Candolle has shown, generally have restricted ranges, could hardly be transported by any other means.
Seeds may be occasionally transported in another manner. Drift timber is thrown up on most islands, even on those in the midst of the widest