LONDON. 71 



tend the publication of the ' Zoology of the Voyage of 

 the Beagle! Nor did I ever intermit collecting facts 

 bearing on the origin of species ; and I could some- 

 times do this when I could do nothing else from 

 illness. 



In the summer of 1842 I was stronger than I had 

 been for some time, and took a little tour by myself in 

 North Wales, for the sake of observing the effects of 

 the old glaciers which formerly filled all the larger 

 valleys. I published a short account of what I saw in 

 the ' Philosophical Magazine/ * This excursion inte- 

 rested me greatly, and it was the last time I was ever 

 strong enough to climb mountains or to take long 

 walks such as are necessary for geological work. 



During the early part of our life in London, I was 

 strong enough to go into general society, and saw 

 a good deal of several scientific men, and other more 

 or less distinguished men. I will give my impressions 

 with respect to some of them, though I have little to 

 say worth saying. 



I saw more of Lyell than of any other man, both 

 before and after my marriage. His mind was charac- 

 terised, as it appeared to me, by clearness, caution, 

 sound judgment, and a good deal of originality. When 

 I made any remark to him on Geology, he never 

 rested until he saw the whole case clearly, and often 

 made me see it more clearly than I had done before. 

 He would advance all possible objections to my 

 suggestion, and even after these were exhausted 

 would long remain dubious. A second characteristic 



* ' Philosophical Magazine,' 1842. 



