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.’