reer--the five years spent
by him on board the "Beagle"--was the one in which by far the most
important stage in his mental development was accomplished. He left
England a healthy, vigorous and enthusiastic collector; he returned five
years later with unique experiences, the germs of great ideas, and
a knowledge which placed him at once in the foremost ranks of the
geologists of that day. Huxley has well said that "Darwin found on board
the "Beagle" that which neither the pedagogues of Shrewsbury, nor the
professoriate of Edinburgh, nor the tutors of Cambridge had managed
to give him." ("Proc. Roy. Soc." Vol. XLIV. (1888), page IX.) Darwin
himself wrote, referring to the date at which the voyage was expected to
begin: "My second life will then commence, and it shall be as a birthday
for the rest of my life." ("L.L." I. page 214.); and looking back on the
voyage after forty years, he wrote; "The voyage of the 'Beagle' has been
by far the most important event in my life, and has determined my whole
career;... I have always 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." ("L.L." I. page
61.)

Referring to these general studies in natural history, however, Darwin
adds a very significant remark: "The investigation of the geology of
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."
("L.L." I. page 62.)

The famous voyage began amid doubts, discouragements and
disappointments. Fearful of heart-disease, sad at parting from home
and friends, depressed by sea-sickness, the young explorer, after being
twice driven back by baffling winds, reached the great object of
his ambition, the island of Teneriffe, only to find that, owing to
quarantine regulations, landing was out of the question.

But soon this inauspicious opening of the voyage was forgotten. Henslow
had advised his pupil to take with him the first volume of Lyell's
"Principles of Geology", then just published