"1842. May 18th went to Maer. June 15th to Shrewsbury, and on 18th to Capel Curig.... During my stay at Maer and Shrewsbury (five years after commencement) wrote pencil sketch of my species theory." Again in a letter to Lyell (June 18, 1858) he speaks of his "MS. sketch written out in 1842{18}." In the _Origin of Species_, Ed. i. p. 1, he speaks of beginning his speculations in 1837 and of allowing himself to draw up some "short notes" after "five years' work," _i.e._ in 1842. So far there seems no doubt as to 1842 being the date of the first sketch; but there is evidence in favour of an earlier date{19}. Thus across the Table of Contents of the bound copy of the 1844 MS. is written in my father's hand "This was sketched in 1839." Again in a letter to Mr Wallace{20} (Jan. 25, 1859) he speaks of his own contributions to the Linnean paper{21} of July 1, 1858, as "written in 1839, now just twenty years ago." This statement as it stands is undoubtedly incorrect, since the extracts are from the MS. of 1844, about the date of which no doubt exists; but even if it could be supposed to refer to the 1842 Essay, it must, I think, be rejected. I can only account for his mistake by the supposition that my father had in mind the date (1839) at which the framework of his theory was laid down. It is worth noting that in his Autobiography (p. 88) he speaks of the time "about 1839, when the theory was clearly conceived." However this may be there can be no doubt that 1842 is the correct date. Since the publication of _Life and Letters_ I have gained fresh evidence on this head. A small packet containing 13 pp. of MS. came to light in 1896. On the outside is written "First Pencil Sketch of Species Theory. Written at Maer and Shrewsbury during May and June 1842." It is not however written in pencil, and it consists of a single chapter on _The Principles of Variation in Domestic Organisms_. A single unnumbered page is written in pencil, and is headed "Maer, May 1842, useless"; it also bears the words "This page was thought of as introduction." It consists of the briefest sketch of the geological evidence for evolution, together with words intended as headings for discussion,--such as "Affinity,--unity of type,--foetal state,--abortive organs." {18} _Life and Letters_, ii. p. 116. {19} _Life and Letters_, ii. p. 10. {20} _Life and Letters_, ii. p. 146. {21} _J. Linn. Soc. Zool._ iii. p. 45. The back of this "useless" page is of some interest, although it does not bear on the question of date,--the matter immediately before us. It seems to be an outline of the Essay or sketch of 1842, consisting of the titles of the three chapters of which it was to have consisted. "I. The Principles of Var. in domestic organisms. "II. The possible and probable application of these same principles to wild animals and consequently the possible and probable production of wild races, analogous to the domestic ones of plants and animals.