Who shall estimate the value of such a friendship to a young man! It was a foregone conclusion that Lyell and Agassiz and Liebig, and others, who sought the society of such as Humboldt, and were _willing to work_, would come to greatness. Cuvier introduced Lyell to Professor Van Breda of Ghent, who gave him letters to all the Dutch universities,--Ghent, Amsterdam, Haarlem, and Leyden. The next year, 1824, Lyell made a geological tour with M. Constant Prévost, a noted French geologist, from London to Bristol and Land's End, and with Dr. Buckland, in Scotland, where they dined with the far-famed Francis Jeffrey, editor of the "Edinburgh Review." Lyell's eyes still troubled him so that he could scarcely write letters home; but he was laying up a store of knowledge from which the world was to profit in a few years. In 1825, his eyes having improved, he resumed his law study, and was admitted to the bar. But he could not give up geological work, and published several papers,--one on a dike of serpentine, another on shell marl and fossil fruit, and others on plastic clay in Hampshire and the fresh-water strata of Hants. He had been made a Fellow of the Royal Society at twenty-nine, and was one of the writers in the "Quarterly Review." The law work went on, but it was easy to see where his heart was. He wrote a friend that he had been "devouring" Lamarck: "That the earth is quite as old as he supposes has long been my creed, and I will try before six months are over to convert the readers of the 'Quarterly' to that heterodox opinion.... Buckland has got a letter from India about modern hyænas, whose manners, habitations, diet, etc., are everything he could wish, and as much as could be expected had they attended regularly three courses of his lectures." At thirty-one Lyell had made up his mind "that there is most real independence in that class of society who, possessing moderate means, are engaged in literary and scientific hobbies;" he had given up the law, and planned the book that was to make him famous--"Principles of Geology." He travelled now extensively in Italy and France, studying volcanoes, glaciers, and fossils. At Auvergne, he began work with his dear friend Murchison at six o'clock in the morning, "and neither heat nor fatigue has stopped us an hour," he writes to his parents. "I have really gained strength so much, that I believe that I and my eyes were never in such a condition before; and I am sure that six hours in bed, which is all we allow, and exercise all day long for the body, and geology for the mind, ... is the best thing that can be invented in this world for my health and happiness."