During this time, Charles met Sir James Mackintosh, "the best converser," he says, "I ever listened to. I heard afterwards, with a glow of pride, that he had said, 'There is something in that young man that interests me.'... To hear of praise from an eminent person, though no doubt apt or certain to excite vanity, is, I think, good for a young man, as it helps to keep him in the right course." After two years at Edinburgh, Dr. Darwin, seeing that Charles probably would never become a physician, sent him to Cambridge University, that he might prepare for the Episcopal ministry. Of this time he says, "The three years which I spent at Cambridge were wasted, as far as the academical studies were concerned, as completely as at Edinburgh and at school. I attempted mathematics, and even went during the summer of 1828 with a private tutor (a very dull man) to Barmouth, but I got on very slowly. The work was repugnant to me, chiefly from my not being able to see any meaning in the early steps in algebra." He found great delight in Paley's "Evidences of Christianity," and his "Moral Philosophy." At Cambridge, like Humboldt, he formed a rare friendship, which helped towards his subsequent success. Professor Henslow was an ardent scholar, a devoted Christian, and a man of most winning manners and good temper. From his great knowledge of botany, entomology, chemistry, mineralogy, and geology, he became a most attractive person to young Darwin, whose especial passion seemed to be the collecting of beetles. Henslow soon became equally fond of Darwin, and the two took long walks together daily, Darwin being known as "the man who walks with Henslow." Darwin said of this model teacher, years afterward, "He had a remarkable power of making the young feel completely at ease with him; though we were all awe-struck with the amount of his knowledge. Before I saw him, I heard one young man sum up his attainments by simply saying that he knew everything. When I reflect how immediately we felt at ease with a man older, and in every way immensely our superior, I think it was as much owing to the transparent sincerity of his character as to his kindness of heart, and, perhaps, even still more to a highly remarkable absence in him of all self-consciousness. One perceived at once that he never thought of his own varied knowledge or clear intellect, but solely on the subject in hand. "Another charm which must have struck every one was that his manner to old and distinguished persons and to the youngest student was exactly the same; and to all he showed the same winning courtesy. He would receive with interest the most trifling observation in any branch of natural history, and, however absurd a blunder one might make, he pointed it out so clearly and kindly that one left him no way disheartened, but only determined to be more accurate the next time.