principle of Natural Selection had been independently recognised by Dr W.C.
Wells in 1813 and by Mr Patrick Matthew in 1831, but he had no knowledge of
these anticipations when he published the first edition of "The Origin of
Species". Wells, whose "Essay on Dew" is still remembered, read in 1813
before the Royal Society a short paper entitled "An account of a White
Female, part of whose skin resembles that of a Negro" (published in 1818).
In this communication, as Darwin said, "he observes, firstly, that all
animals tend to vary in some degree, and, secondly, that agriculturists
improve their domesticated animals by selection; and then, he adds, but
what is done in this latter case 'by art, seems to be done with equal
efficacy, though more slowly, by nature, in the formation of varieties of
mankind, fitted for the country which they inhabit.'" ("Origin of Species"
(6th edition) page xv.) Thus Wells had the clear idea of survival
dependent upon a favourable variation, but he makes no more use of the idea
and applies it only to man. There is not in the paper the least hint that
the author ever thought of generalising the remarkable sentence quoted
above.

Of Mr Patrick Matthew, who buried his treasure in an appendix to a work on
"Naval Timber and Arboriculture", Darwin said that "he clearly saw the full
force of the principle of natural selection." In 1860 Darwin wrote--very
characteristically--about this to Lyell: "Mr Patrick Matthew publishes a
long extract from his work on "Naval Timber and Arboriculture", published
in 1831, in which he briefly but completely anticipates the theory of
Natural Selection. I have ordered the book, as some passages are rather
obscure, but it is certainly, I think, a complete but not developed
anticipation. Erasmus always said that surely this would be shown to be
the case some day. Anyhow, one may be excused in not having discovered the
fact in a work on Naval Timber." ("Life and Letters" II. page 301.)