He seems to have led a somewhat double life at Cambridge, his intense love of sport taking him into a pleasure-loving set, while his intellectual interests made him the intimate friend of Whitley, who became Senior Wrangler, and of Professor Henslow, to whom he was introduced by his second cousin, W. Darwin Fox, who also first interested him in entomology. He became so keen a collector of beetles that his successes and experiences in this direction seem to have impressed him more deeply than anything else at Cambridge. Entomology, and especially beetles, form the chief subject of those of his Cambridge letters which have been recovered. Darwin’s friendship with Henslow, which was to have a most important effect on his life, very soon deepened. They often went long walks together, so that he was called “the man who walks with Henslow.” This fact and the subsequent rapidly formed intimacy with Professor Adam Sedgwick, indicate that he was remarkable among the young men of his standing. One of his undergraduate friends, J. M. Herbert, afterwards County Court Judge for South Wales, retained the most vivid recollection of Darwin at Cambridge, and contributed the following impression of his character to the “Life and Letters”:-- “It would be idle for me to speak of his vast intellectual powers ... but I cannot end this cursory and rambling sketch without testifying, and I doubt not all his surviving college friends would concur with me, that he was the most genial, warm-hearted, generous and affectionate of friends; that his sympathies were with all that was good and true; and that he had a cordial hatred for everything false, or vile, or cruel, or mean, or dishonourable. He was not only great, but pre-eminently good, and just, and loveable.” Two books greatly influenced Darwin--Herschel’s “Introduction to the Study of Natural Philosophy,” which, he said, “stirred up in me a burning zeal to add even the most humble contribution to the noble structure of Natural Science”; and Humboldt’s “Personal Narrative,” which roused in him the longing to travel--a desire which was soon afterwards gratified by his voyage in the _Beagle_. “Upon the whole,” he says, “the three years which I spent at Cambridge were the most joyful in my happy life; for I was then in excellent health, and almost always in high spirits.” After passing his last examination, Darwin had still two terms’ residence to keep, and was advised by Henslow to study geology. To this end Henslow asked Sedgwick to allow Darwin to go with him on a geological excursion in North Wales in August, 1831. He thus gained experience which was of the utmost value during the voyage of the _Beagle_. CHAPTER III. VOYAGE OF THE “BEAGLE” (1831–36).