s felt that I owe to the voyage the
first real training or education of my mind; I was led to attend
closely to several branches of natural history, and thus my powers of
observation were improved, though they were always fairly developed.

The investigation of the geology of all the places visited was far more
important, as reasoning here comes into play. On first examining a new
district nothing can appear more hopeless than the chaos of rocks; but
by recording the stratification and nature of the rocks and fossils
at many points, always reasoning and predicting what will be found
elsewhere, light soon begins to dawn on the district, and the structure
of the whole becomes more or less intelligible. I had brought with me
the first volume of Lyell's 'Principles of Geology,' which I studied
attentively; and the book was of the highest service to me in many ways.
The very first place which I examined, namely St. Jago in the Cape de
Verde islands, showed me clearly the wonderful superiority of Lyell's
manner of treating geology, compared with that of any other author,
whose works I had with me or ever afterwards read.

Another of my occupations was collecting animals of all classes, briefly
describing and roughly dissecting many of the marine ones; but from not
being able to draw, and from not having sufficient anatomical knowledge,
a great pile of MS. which I made during the voyage has proved almost
useless. I thus lost much time, with the exception of that spent in
acquiring some knowledge of the Crustaceans, as this was of service when
in after years I undertook a monograph of the Cirripedia.

During some part of the day I wrote my Journal, and took much pains in
describing carefully and vividly all that I had seen; and this was good
practice. My Journal served also, in part, as letters to my home, and
portions were sent to England whenever there was an opportunity.

The above various special studies were, however, of no importance
compared with the habit of energetic industry and of concentrated
attention to whatever I was engaged in, which I then acquired.
Everything about which I thought or read was made to bear directly
on what I had seen or was likely to see; and this habit of mind was
continued during the five years of the voyage. I feel sure that it
was this training which has enabled me to do whatever I have done in
science.

Looking backwards, I can now perceive how my love for science gradually
prepondera