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 whatever scientific merit this Journal and the other works of the author may possess has been derived from studying the well known and admirable "Principles 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 professional 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 Henslow, by Sedgwick and by Lyell was unconsciously 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 we 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 uninhabited, 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 impression 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 exclamation on my return, "why the shape of his head is quite altered."
III
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
