Chap. XU.] MEANS OF DISPEESAL. 145 



the small, is interesting ; as plants with large seeds or 

 fruit which, as Alph. de CandoUe 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 oceans ; and 

 the natives of the coral-islands in the Pacific procure 

 stones for their tools, solely from the roots of drifted 

 trees, these stones being a valuable royal tax. I find 

 that when irregularly shaped stones are embedded in 

 the roots of trees, small parcels of earth are frequently 

 enclosed in their interstices and behind them, — so 

 perfectly that not a particle could be washed away 

 during the longest transport : out of one small portion 

 of earth thus completely enclosed by the roots of an 

 oak about 50 years old, three dicotyledonous plants 

 germinated : I am certain of the accuracy of this obser- 

 vation. Again, I can show that the carcases of birds, 

 when floating on the sea, sometimes escape being im- 

 mediately devoured : and many kinds of seeds in the 

 crops of floating birds long retain their vitality : peas 

 and vetches, for instance, are killed by even a few days' 

 immersion in sea- water ; but some taken out of the 

 crop of a pigeon, which had floated on artificial sea- 

 water for 30 days, to my surprise nearly all germinated. 



Living birds can hardly fail to be highly effective 

 agents in the transportation of seeds. I could give 

 many facts showing how frequently birds of many kinds 

 are blown by gales to vast distances across the ocean. 

 We may safely assume that under such circumstances 

 their rate of flight would often be 35 miles an hour; 

 and some authors have given a far higher estimate. I 



