for it brought him into direct contact with the principles on
which naturalists found 'species[128].' And Hooker has expressed the
same opinion.

Daring these years of labour in geology and zoology--interrupted only by
the 'hours of idleness'--devoted to 'the species question,' Darwin,
though leading at Down almost the life of a hermit, was nevertheless in
frequent communication with two or three faithful friends who followed
his labours with the deepest interest. Cautious as was Darwin himself,
he found in his life-long friend Lyell, a still more doubting and
critical spirit, and it is clear from what Darwin says that he derived
much help by laying new ideas and suggestions before him. The year
before Darwin's death he wrote of Lyell, 'When I made a remark to him on
Geology, he never rested till he saw the whole case clearly, and often
made me see it more clearly than I had done before.'

Lyell's father was a botanist of considerable repute, the friend of Sir
William Hooker and his distinguished son Dr (now Sir Joseph) Hooker.
While Darwin was writing his _Journal of Researches_, he handed the
proof-sheets to Lyell with permission to show them to his father, who
was a man of great literary judgment. The elder Lyell, in turn, showed
them to young Mr Hooker, who was then preparing to join Sir James Ross,
in his celebrated Antarctic voyage with H.M. ships _Erebus_ and
_Terror_. Hooker was then working hard to take his doctor's degree
before joining the expedition as surgeon, but he kept Darwin's
proof-sheets under his pillow, so as to get opportunities of reading
them 'between waking and rising.' Before leaving England, however,
Hooker in 1839 casually met and was introduced to Darwin, and thus
commenced a friendship which resulted in such inestimable benefits to
science. Before sailing with the Antarctic expedition the young surgeon
received from Charles Lyell, as a parting gift, 'a copy of Darwin's
_Journal_ complete'; and he tells us that the perusal stimulated in him
'an enthusiasm in the desire to travel and observe[129].'

On Hooker's return from the voyage in 1843, a friendly letter from
Darwin commenced that remarkable correspondence, which will always
afford the best means of judging of the development of ideas in Darwin's
mind. Hooker's wide knowledge of plants--especially of all questions
concerning their distribution--was of invaluable assistance to Darwin,
at a time when his attention was more particularly