never be forgotten. Many of my
excursions on horseback through wild countries, or in the boats, some
of which lasted several weeks, were deeply interesting: their discomfort
and some degree of danger were at that time hardly a drawback, and none
at all afterwards. I also reflect with high satisfaction on some of
my scientific work, such as solving the problem of coral islands, and
making out the geological structure of certain islands, for instance,
St. Helena. Nor must I pass over the discovery of the singular relations
of the animals and plants inhabiting the several islands of the
Galapagos archipelago, and of all of them to the inhabitants of South
America.

As far as I can judge of myself, I worked to the utmost during the
voyage from the mere pleasure of investigation, and from my strong
desire to add a few facts to the great mass of facts in Natural
Science. But I was also ambitious to take a fair place among scientific
men,--whether more ambitious or less so than most of my fellow-workers,
I can form no opinion.

The geology of St. Jago is very striking, yet simple: a stream of lava
formerly flowed over the bed of the sea, formed of triturated recent
shells and corals, which it has baked into a hard white rock. Since then
the whole island has been upheaved. But the line of white rock revealed
to me a new and important fact, namely, that there had been afterwards
subsidence round the craters, which had since been in action, and had
poured forth lava. It then first dawned on me that I might perhaps write
a book on the geology of the various countries visited, and this made me
thrill with delight. That was a memorable hour to me, and how distinctly
I can call to mind the low cliff of lava beneath which I rested, with
the sun glaring hot, a few strange desert plants growing near, and
with living corals in the tidal pools at my feet. Later in the voyage,
Fitz-Roy asked me to read some of my Journal, and declared it would be
worth publishing; so here was a second book in prospect!

Towards the close of our voyage I received a letter whilst at Ascension,
in which my sisters told me that Sedgwick had called on my father, and
said that I should take a place among the leading scientific men. I
could not at the time understand how he could have learnt anything of
my proceedings, but I heard (I believe afterwards) that Henslow had
read some of the letters which I wrote to him before the Philosophical
Society of Cambridge