152 THE ORIGIN OR, SPECIES 



species with ripe frait (but not all the same species as 

 in the foregoing experiment) floated, after being dried, 

 for above 28 days, we may conclude, as far as anything 

 can be inferred from these scanty facts, that the seeds 

 of fo^ kinds of plants of any country might be floated 

 by sea-currents during 28 days, and would retain their 

 power of germination. In Johnston's Physical Atlas, the 

 average rate of the several Atlantic currents is 83 miles 

 per diem (some currents running at the rate of 60 miles 

 per diem); on this average, the seeds of i^oV plants be- 

 longing 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 favorable 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 98 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 

 favored both the average length of their flotation and 

 their resistance to the injurious action of the salt water. 

 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 H of his seeds of different 

 kinds floated for 42 days, and were then capable of ger- 

 mination. 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. There- 

 fore it would perhaps be safer to assume that the seeds 

 of about T^nr plants of a flora, after having been dried. 



