Charles Darwin

Darwin now had the framework of his theory of natural selection "by which to work", as his "prime hobby”. His research included animal husbandry and extensive experiments with plants, finding evidence that species were not fixed and investigating many detailed ideas to refine and substantiate his theory. For fifteen years this work was in the background to his main occupation of writing on geology and publishing expert reports on the Beagle collections.
Darwin's book The Structure and Distribution of Coral Reefs on his theory of atoll formation was published in May 1842 after more than three years of work, and he then wrote his first "pencil sketch" of his theory of natural selection. By July, Darwin had expanded his "sketch" into a 230-page "Essay", to be expanded with his research results if he died prematurely.…