18671882] DISPERSAL OF SEEDS 5 



9 grains, and from this the Juncus bufonius, or toad rush, Letter 381 

 germinated. By the way, the locust case verifies what I said 

 in the Origin, that many possible means of distribution would 

 be hereafter discovered. I quite agree about the extreme 

 difficulty of the distribution of land mollusca. You will have 

 seen in the last edition of Origin 1 that my observations on the 

 effects of sea- water have been confirmed. I still suspect that 

 the legs of birds which roost on the ground may be an efficient 

 means ; but I was interrupted when going to make trials on 

 this subject, and have never resumed it. 



We shall be in London in the middle or latter part of 

 November, when I shall much enjoy seeing you. Emma 

 sends her love, and many thanks for Lady Lyell's note. 



To J. D. Hooker. Letter 382 



Down, Wednesday [1867]. 



I daresay there is a great deal of truth in your remarks 

 on the glacial affair, but we are in a muddle, and shall 

 never agree. I am bigoted to the last inch, and will not 

 yield. I cannot think how you can attach so much weight 

 to the physicists, seeing how Hopkins, Hennessey, Haughton, 

 and Thomson have enormously disagreed about the rate of 

 cooling of the crust ; remembering Herschel's speculations 

 about cold space, 2 and bearing in mind all the recent specula- 

 tions on change of axis, I will maintain to the death that 

 your case of Fernando Po and Abyssinia 3 is worth ten times 



1 Origin, Ed. iv. 5 p. 429. The reference is to MM. Marten's experi- 

 ments on seeds " in a box in the actual sea." 



2 The reader will find some, account of Herschel's views in LvelPs 



j 



Principles, 1872, Ed. XL, Vol. I., p. 283. 



3 See Origin, Ed. vi., p. 337 : "Dr. Hooker has also lately shown 

 that several of the plants living on the upper parts of the lofty island ot 

 Fernando Po and on the neighbouring Cameroon mountains, in the Gulf 

 of Guinea, are closely related to those in the mountains of Abyssinia, 

 and likewise to those of temperate Europe." Darwin evidently means 

 that such facts as these are better evidence of the gigantic periods of 

 time occupied by evolutionary changes than the discordant conclusions 

 of the physicists. See Linn. Soc.Journ., Vol. VII., p. 180, for Hooker's 

 general conclusions ; also Hooker and Ball's Marocco, Appendix F, p. 421. 

 For the case of Fernando Po see Hooker (Linn. Soc.Journ. VI., 1861, 

 p. 3, where he sums up : " Hence the result of comparing Clarence Peak 

 flora [Fernando Po] with that of the African continent is (i) the 



