After the returned to England in October 1836, Darwin began reflecting on his observations and experiences, and over the next two years developed the basic outline of his groundbreaking theory of evolution through natural selection.
But beyond sharing his ideas with a close circle of scientist friends, Darwin told no one of his views on the origin and development of life.
This evolution, Darwin wrote, is due to two factors.
The first factor, Darwin argued, is that each individual animal is marked by subtle differences that distinguish it from its parents.
Darwin had expected no less – fear of a backlash from Britain’s religious and even scientific establishment had been the primary reason he had delayed publicizing his ideas.
Yet the concept of species adaptation was not so radical at the time.This being the age of Victorian gentlemen, it was agreed that the two scientists would jointly publish their writings on the subject.Their work – comprising a collection of Darwin’s earlier notes and an essay by Wallace – was read to the Linnean Society, an association of naturalists, in London on July 1, 1858.(See the Cambridge University Library Order Form for Digital Images.) They are presented in the same sequence as the original catalogue, which was divided mostly into bound volumes, each with a library classmark.History of the material: The Darwin family and the Pilgrim Trust presented a magnificent collection of Darwin's papers to Cambridge University Library in 1942; they were delivered after the war.For online publication now a slight colour tint has been added to many and the brightness and contrast have been digitally enhanced.(To compare a document with and without the colour tint click here and here.) Please note that many of the Darwin papers have been re-catalogued since microfilming in the 1990s.As the 1960 They were in parcels each containing small packets of manuscript wrapped in tissue paper on which the subjects had been noted in Darwin's hand.They were presumably just as Darwin left them, and accordingly this arrangement was preserved when they were bound, the volumes now representing as closely as possible Charles Darwin's papers in the order in which he left them.In some cases items have been re-ordered or moved to other volumes in the archive.In such cases the electronic images may not match the current arrangement of the papers in Cambridge University Library.