ch. ii.] VOYAGE. 29 



the stratification and nature of the rocks and fossils at many- 

 points, always reasoning and predicting what will be found 

 elsewhere, light soon begins to dawn on the district, and the 

 structure of the whole becomes more or less intelligible. 

 I had brought with me the first volume of Lyell's Principles 

 of Geology, which I studied attentively ; and the book was 

 of the highest service to me in many ways. The very first 

 place which I examined, namely, St. J ago, in the Cape 

 de Verde islands, showed me clearly the wonderful superi- 

 ority of Lyell's manner of treating geology, compared with 

 that of any other author wdiose works I had with me or ever 

 afterwards read. 



Another of my occupations was collecting animals of all 

 classes, briefly describing and roughly dissecting many of 

 the marine ones ; but from not being able to draw, and 

 from not having sufficient anatomical knowledge, a great 

 pile of MS. which I had made during the voyage has proved 

 almost useless. I thus lost much time, with the exception 

 of that spent in acquiring some knowledge of the Crusta- 

 ceans, as this was of service w T hen in after years I un- 

 dertook a monograph of the Cirripedia. 



During some part of the day I wrote my Journal, and 

 took much pains in describing carefully and vividly all 

 that I had seen ; and this was good practice. My Journal 

 served also, in part, as letters to my home, and portions 

 were sent to England whenever there was an opportunity. 



The above various special studies were, however, of no 

 importance compared with the habit of energetic industry 

 and of concentrated attention to whatever I was engaged 

 in, which I then acquired. Everything about which I 

 thought or read was made to bear directly on what I had 

 seen or was likely to see ; and this habit of mind was con- 

 tinued during the five years of the voyage. I feel sure that 

 it was this training which has enabled me to do whatever I 

 have done in science. 



Looking backwards, I can now perceive how my love for 

 science gradually preponderated over every other taste. Dur- 

 ing the first two years my old passion for shooting survived in 

 nearly full force, and I shot myself all the birds and animals 

 for my collection ; but gradually I gave up my gun more 

 and more, and finally altogether, to my servant, as shooting 

 interfered with my work, more especially with making 

 out the geological structure of a country. I discovered, 

 though unconsciously and insensibly, that the pleasure 



