cessary to impress on him the remarkable characteristic species of the
different islands. We agree with Mr. Huxley that 1837 is the date of
the "new light which was rising in his mind." That the dawn did not come
sooner seems to us to be accounted for by the need of time to produce so
great a revolution in his conceptions. We do not see that Mr. Huxley's
supposition as to the effect of the determination of species, etc., has
much weight. Mr. Huxley quotes a letter from Darwin to Zacharias, "But
I did not become convinced that species were mutable until, I think, two
or three years [after 1837] had elapsed" (see Letter 278). This
passage, which it must be remembered was written in 1877, is all but
irreconcilable with the direct evidence of the 1837 note-book. A series
of passages are quoted from it in the "Life and Letters," Volume II.,
pages 5 et seq., and these it is impossible to read without feeling that
he was convinced of immutability. He had not yet attained to a clear
idea of Natural Selection, and therefore his views may not have had,
even to himself, the irresistible convincing power they afterwards
gained; but that he was, in the ordinary sense of the word, convinced
of the truth of the doctrine of evolution we cannot doubt. He thought it
"almost useless" to try to prove the truth of evolution until the cause
of change was discovered. And it is natural that in later life he should
have felt that conviction was wanting till that cause was made out.
(Chapter II./7. See "Charles Darwin, his Life told, etc." 1892, page
165.) For the purposes of the present chapter the point is not very
material. We know that in 1842 he wrote the first sketch of his theory,
and that it was greatly amplified in 1844. So that, at the date of the
first letters of this chapter, we know that he had a working hypothesis
of evolution which did not differ in essentials from that given in the
"Origin of Species."

To realise the amount of work that was in progress during the period
covered by Chapter II., it should be remembered that during part of the
time--namely, from 1846 to 1854--he was largely occupied by his work on
the Cirripedes. (Chapter II./8. "Life and Letters," I. page 346.) This
research would have fully occupied a less methodical workman, and even
to those who saw him at work it seemed his whole occupation. Thus (to
quote a story of Lord Avebury's) one of Mr. Darwin's children is said
to have asked, in regard to a neighbour, "