vii] OF EVOLUTION 79 



Of the influence of the Principles of Geology in 

 leading him to evolution, he wrote : 



' Along with Malthus I had read, and been even more deeply 

 impressed by, Sir Charles Lyell's immortal Principles of Geology ; 

 which had taught me that the inorganic world the whole surface 

 of the earth, its seas and lands, its mountains and valleys, its 

 rivers and lakes, and every detail of its climatic conditions were 

 and always had been in a continual state of slow modification. 

 Hence it became obvious that the forms of life must have become 

 continually adjusted to these changed conditions in order to 

 survive. The succession of fossil remains throughout the whole 

 geological series of rocks is the record of the change ; and it 

 became easy to see that the extreme slowness of these changes 

 was such as to allow ample opportunity for the continuous 

 automatic adjustment of the organic to the inorganic world, as 

 well as of each organism to every other organism in the same 

 area, by the simple processes of "variation and survival of the 

 fittest." Thus was the fundamental idea of the "origin of 

 species " logically formulated from the consideration of a series of 

 well ascertained facts 76 .' 



Nor were the two men (who, like Aaron and Hur 

 so steadily sustained the hands of Darwin in his long 

 vigil), behind the two authors of Natural Selection 

 themselves in their devotion to Lyell. How touching 

 is Hooker's tribute of affection on the death of his 

 friend, ' My loved, my best friend, for well nigh forty 

 years of my life. To me the blank is fearful, for it 

 never will, never can be filled up. The most generous 

 sharer of my own and my family's hopes, joys, and 



