But the inherent tendencies of Darwin's nature drew him away from
theology to the study of geology, entomology and botany. The ensuing
four years at Cambridge were very happy ones. While fortunate in being
able to follow his various mental and scientific pursuits with the
freedom which a good social and financial position secured for him, he
found himself by a natural seriousness of manner, balanced by a cheerful
temperament and love of sport, the friend and companion of men many
years his seniors and holding positions of authority in the world of
science. Amongst these the name of Professor Henslow will always take
precedence. "This friendship," says Darwin, "influenced my whole career
more than any other." Henslow's extensive knowledge of botany, geology,
entomology, chemistry and mineralogy, added to his sincere and
attractive personality, well-balanced mind and excellent judgment,
formed a strong and effective bias in the direction Darwin was destined
to follow.

Apart, however, from the strong personal influence of Henslow, Sedgwick
and others with whom he came much in contact, two books which he read at
this time aroused his "burning zeal to add the most humble contribution
to the noble structure of Natural Science"; these were Sir J. Herschel's
"Introduction to the Study of Natural Philosophy," and Humboldt's
"Personal Narrative." Indeed, so fascinated was he by the description
given of Teneriffe in the latter that he at once set about a plan
whereby he might spend a holiday, with Henslow, in that locality, a
holiday which was, indeed, to form part of his famous voyage.

By means of his explorations in the neighbourhood of Cambridge, and one
or two visits to North Wales, Darwin's experimental knowledge of geology
and allied sciences was considerably increased. In his zeal for