page_title: Development of Darwin's theory
section_title: Essay
hierarchical_section_title: Development of Darwin's theory / First writings on the theory / Essay
caption_attribution_description: Gower Street, London. Looking south.
context_page_description: Following the inception of Charles Darwin's theory of natural selection in 1838, the development of Darwin's theory to explain the "mystery of mysteries" of how new species originated was his "prime hobby" in the background to his main occupation of publishing the scientific results of the Beagle voyage. He was settling into married life, but suffered from bouts of illness and after his first child was born the family moved to rural Down House as a family home away from the pressures of London.
  The publication in 1839 of his Journal and Remarks brought him success as an author, and in 1842 he published his first major scientific book, The Structure and Distribution of Coral Reefs, setting out his theory of the formation of coral atolls. He wrote out a sketch setting out his basic ideas on transmutation of species, which he expanded into an "essay" in 1844, and discussed his theory with friends as well as continuing with experiments and wide investigations. In the same year the anonymous Vestiges of the Natural History of Creation brought wide public interest in evolutionary ideas, but also showed the need for sound evidence to gain scientific acceptance of evolution.
context_section_description: They returned on 18 July to a London seething with Chartist unrest, and Darwin copied and scribbled changes to his "Sketch" until it was almost illegible. He returned to house hunting and found a former parsonage in the rural hamlet of Downe at a good price. A general strike led to huge demonstrations all over London, but was crushed by troops by the time Darwin moved. On 17 September 1842 the family moved into Down House (around 1850 the village changed its name to Downe to avoid confusion with County Down in Ireland, but the house kept the old spelling). After a series of alterations Darwin settled in, and in 1843 returned to writing his Volcanic Islands. In May he began a (mostly geological) country diary he called The General Aspect. 
  In response to a request from George Robert Waterhouse for advice on classification, Darwin replied that it properly "consists in grouping beings according to their actual relationship, ie their consanguinity, or descent from common stocks". He followed this up with another letter expressing belief that "all the orders, families & genera amongst the Mammals are merely artificial terms highly useful to show the relationship of those members of the series, which have not become extinct",  before cautiously asking for the letter to be returned. Waterhouse was influenced by Owen and in a paper attacked such heresies, setting his species in the symbolic circles of the Quinarian system, not hereditary trees. Darwin sent a sharp response about these "vicious circles". 
  Darwin became a close friend of the botanist Joseph Dalton Hooker, and on 11 January 1844 wrote to with melodramatic humour that he was "almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable. Heaven forfend me from Lamarck nonsense of a "tendency to progression" “adaptations from the slow willing of animals" &c,—but the conclusions I am led to are not widely different from his—though the means of change are wholly so— I think I have found out (here's presumption!) the simple way by which species become exquisitely adapted to various ends." Hooker's reply was cautious but friendly, saying that "There may in my opinion have been a series of productions on different spots, & also a gradual change of species. I shall be delighted to hear how you think that this change may have taken place, as no presently conceived opinions satisfy me on the subject."
  Darwin worked up his "Sketch" into a 189-page '"Essay"' and in July entrusted the manuscript to the local schoolmaster to copy. He then wrote a difficult letter to be opened by his wife in the event of his death requesting that the essay be published posthumously. He started his Geological Observations on South America, and corresponded with Hooker about this, feeding in questions related to his "Essay". The copied "Essay", now 231 pages, was returned to him for corrections in September. Then one day he brought it to Emma and asked her to read it. She went through the pages, making notes in the margins pointing out unclear passages and showing where she disagreed.
  The Reverend Leonard Jenyns, a naturalist Darwin had known since his time at the University of Cambridge, had at Darwin's request contributed the volume on Fish in Zoology of the Voyage of H.M.S. Beagle, and was now working on a book of notes on observations of plants and animals. On 12 October Darwin wrote to tell him that "work on the species question has impressed me very forcibly with the importance of all such works, as your intended one, containing what people are pleased generally to call trifling facts. These are the facts, which make one understand the working or œconomy of nature .... namely what are the checks & what the periods of life, by which the increase of any given species is limited." He told Jenyns that he had "continued steadily reading & collecting facts on variation of domestic animals & plants & on the question of what are species; I have a grand body of facts & I think I can draw some sound conclusions. The general conclusion at whi
caption: The Darwins lived in Gower Street in London.
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