1856.
May 14th: "Began, by Lyell's advice, writing Species Sketch" (described in "Life and Letters" as the "Unfinished Book").
December 16th: Finished Chapter III. Paper read to Linnean Society, On Sea-water and the Germination of Seeds.
1857.
September 29th: Finished Chapters VII. and VIII.
September 30th to December 29th: Working on Hybridism. Paper on the Agency of Bees in the Fertilisation of Papilionaceous Flowers.
1858.
March 9th: "Finished Instinct chapter."
June 18th: Received Mr. Wallace's sketch of his evolutionary theory.
July 1st: Joint paper of Darwin and Wallace read at the Linnean Society.