324 TEE POPULAR SCIENCE MONTHLY 



always so characteristic of him his tribute to Lyell is without reserve. 

 The second edition is dedicated : 



With grateful pleasure as an acknowledgment that the chief part of what- 

 ever scientific merit this Journal and the other works of the author may 

 possess has been derived from studying the well known and admirable " Prin- 

 ciples of Geology." 



The five years of the voyage filled the twenty-second to twenty- 

 seventh years of Darwin's life, the period now ordinarily given to pro- 

 fessional studies. In reading this simply written but fascinating book, 

 which stands quite by itself in literature, we see how Darwin through 

 his own genius and through the methods successively impressed upon 

 him by his father, by Ilenslow, by Sedgwick and by Lyell was uncon- 

 sciously preparing his mind for the " Origin of Species " and the 

 " Descent of Man," the two most influential books of science which 

 have ever appeared. From the islands of the Atlantic and the Pacific 

 Ave follow his delightful comments on animals and plants of all kinds 

 on sea and land, through forests, pampas and steppes, up the dry 

 slopes of the Andes, along the salt lakes and deserts of Chili and of 

 Australia. The dense forests of Brazil pendent with orchids and gay 

 with butterflies contrast with those of Terra del Fuego and of Tahiti, 

 and with the deforested Cape de Verde Islands. On these islands, the 

 first he visits, he is enormously impressed by the superiority of Ly ell's 

 method. He visits other islands of all kinds, inhabited and uninhabi- 

 ted, the non-volcanic St. Paul's rocks, half -submerged volcanic cones, 

 coral reefs and islands of the south Pacific. He observes live glaciers, 

 as well as the contrasting action of active and of dead volcanoes. 

 Along the rivers of Patagonia he unearths great extinct or fossil 

 mammals ; in Peru he studies the extinct races of man ; the aborigines 

 of Terra del Fuego and of Patagonia make the most profound impres- 

 sion upon his mind. In brief, he sees the great drama of nature in 

 all its lesser scenes and in all its grander acts. He begins the voyage 

 a firm believer in the fixity of species, but doubts begin to enter his 

 mind when in the sands of the pampas of South America he perceives 

 that the extinct forms are partly ancestral to the living, and when on 

 the isolated Galapagos Islands he finds the life is not that of a special 

 creation but that detached from the continent of South America six 

 hundred miles distant. 



Darwin says : 



I owe to the voyage the first real training and education of my mind. 

 That my mind had developed is rendered probable by my father's first exclama- 

 tion on my return, " why the shape of his head is quite altered." 



Ill 



Soon after Darwin's return he moved to London for the two most 

 active years of his life, to care for his collections and to write up his 



