112 J. HOPKTXSOX ANNIVEESAET ADDRESS : 



and for three years (1838-41) acts as one of the Secretaries of the 

 Geological Society. In January, 1839, he marries his cousin, 

 Emma Wedgwood, grand-daughter of the founder of Etruria, and 

 in the same year he is elected a Fellow of the Royal Society. 



The bustle and stir of London life are not congenial to him, and 

 suit his health so badly that in 1842 he resolves to live in the 

 country. In September of this year he buys a house at Down in 

 Kent, with eighteen acres of land, and there he resided for the rest 

 of his life, — a life henceforth entirely devoted to scientific work. 

 In 1846 he writes to Captain Fitz-Roy : "My life goes on like 

 clockwork, and I am fixed to the spot where I shall end it." 



From 1837 to 1846 he is almost entirely occupied in writing the 

 works above mentioned relating to the voyage of the " Beagle," 

 part of the year 1845 being devoted to the preparation of a 

 new edition of his ' Journal.' During these ten years he is also 

 engaged upon his greatest work, ' The Origin of Species by 

 Means of iS^atural Selection,' having opened his first note-book on 

 the subject in July, 1837. But he had not then conceived the 

 idea that specific differences arise by the advantage a favourable 

 variation possesses in the general struggle for existence, for he 

 says : " In October, 1838, that is fifteen months after I had begun 

 my systematic enquiry, I happened to read for amusement Malthus 

 ' On Population,' and being well prepared to appreciate the 

 struggle for existence which everywhere goes on, from long- 

 continued observation of the habits of animals and plants, it at 

 once struck me that under these circumstances favourable variations 

 would tend to be preserved, and unfavourable ones to be destroyed. 

 The result of this would be the formation of new species. . . . 

 But at that time I overlooked one problem of great importance. 

 .... This problem is the tendency in organic beings descended 

 from the same stock to diverge in character as they become 



modified The solution, as I believe, is that the modified 



offspring of all dominant and increasing forms tend to become 

 adapted to many and highly-diversified places in the economy of 

 nature." Here are expressed the three leading principles of his 

 theory of the origin of species — the struggle for existence, the 

 survival of the fittest, and the adaptability of modified forms to 

 their environment. 



In 1846 he begins to work on the Cirripedia (barnacles), and 

 in eight years he completes a monograph of the recent species, 

 published by the Hay Society, and another of the fossil species, 

 published by the Pala^ontographical Society. 



From 1854 to 1859 he devotes nearly all his attention to 



