In the preceding chapter I have endeavoured to show how the hypothesis of Natural Selection originated in the minds of its authors, and must now invite attention to the way in which it was introduced to the world. What has been said earlier with respect to the labours and writings of Hutton, Scrope and Lyell may serve to indicate the great importance of the _manner_ of presentment of new ideas--the logical force and literary skill with which they are brought to the notice of scientific contemporaries and the world at large. There are some striking passages in Darwin's naive 'autobiography and letters' which indicate the beginnings of his ambition for literary distinction. It must always be borne in mind in reading this autobiography, however, that it was not intended by Darwin for publication, but only for the amusement of the members of his own family. But the charming and unsophisticated self-revelations in it will always be a source of delight to the world. When making his first original observations among the volcanic cones and craters of St Jago in the Cape-de-Verde Islands, he says 'It then first dawned on me that I might perhaps write a book on the geology of the different countries visited, and this made me thrill with delight[119].' He tells us concerning his regular occupations on board the _Beagle_, that '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[120].' 'Later in the voyage' he says 'FitzRoy' (the Captain of the _Beagle_) 'asked me to read some of my Journal and declared it would be worth publishing, so here was a second book in prospect[121]!' Darwin's first published writings were the extracts from his letters which Henslow read to the Philosophical Society of Cambridge, and those which Sedgwick submitted to the Geological Society. At Ascension, on the voyage home, a letter from Darwin's sisters had informed him of the commendation with which Sedgwick had spoken to his father of these papers, and he wrote fifty years afterwards: 'After reading this letter, I clambered over the mountains of Ascension with a bounding step, and made the volcanic rocks ring under my geological hammer.' When in 1839 his charming _Journal of Researches_ was published he records that 'The success of this my first literary child always tickles my vanity more than that of any of my other books[122].'