1 859.] PROOF SHEETS. 159 



C. Danvin to C. LyelL 



Down, June 2ist [1859]. 



MY DEAR LYELL, It was extremely kind of you to take so 

 much trouble to tell me about Haldeman's paper,* which I 

 read several years ago and abstracted, and I have just looked 

 at my abstract. I well remember thinking it a very clever 

 paper ; but I did not find much of any actual use to me. 

 I think I h^tve quoted him in my large book about ranges of 

 varieties, but in my present condensed volume I have not 

 alluded to the paper. The speculations approach mine and 

 Wallace's, but did not on any point seem to me identical. 

 Some remarks as to the young of some fresh-water shell 

 struck me most, apparently a modified sea mollusc. 



You ask about specific centres : if you change terms into 

 specific areas, my theory quite requires them ; i.e. it is, 

 I think, quite next door to an impossibility that the same 

 species should have been formed identically the same in any 

 two areas. This point is discussed in my volume. 



... I am working very hard, but get on slowly, for I find 

 that my corrections are terrifically heavy, and the work most 

 difficult to me. I have corrected 130 pages, and the volume 

 will be about 500. I have tried my best to make it clear and 

 striking, but very much fear that I have failed so many dis- 

 cussions are and must be very perplexing. I have done my 

 best. If you had all my materials, I am sure you would have 

 made a splendid book. I long to finish, for I am nearly 

 worn out. 



My dear Lyell, ever yours most truly, 



C. DARWIN. 



C. Darwin to J. D. Hooker. 



Down, 22nd [June, 1859]. 



MY DEAR HOOKER, I did not answer your pleasant note, 

 with a good deal of news to me, of May 3Oth, as I have 



* ' Boston Journal of Nat. History,' vol. iv. 1843-44. 



