Such are the new credentials with which I present myself, as I bring my thanks for the honor paid to me by my nomination for the vacancy in the Royal Society of London. If unbounded devotion to the interests of science constituted a sufficient title to such a distinction, I should be the less surprised at the announcement contained in your last letter. The action of the Royal Society, so flattering to the candidate of your choice, has satisfied a desire which I should hardly have dared to form for many a year,--that of becoming a member of a body so illustrious as the Royal Society of London. . . Each time I write I wish I could close with the hope of seeing you soon; but I must work incessantly; that is my lot, and the happiness I find in it gives a charm to my occupations however numerous they may be. . . While Agassiz's various zoological works were thus pressed with unceasing activity, the glaciers and their attendant phenomena, which had so captivated his imagination, were ever present to his thought. In August of the year 1838, a year after he had announced at the meeting of the Helvetic Society his comprehensive theory respecting the action of ice over the whole northern hemisphere, he made two important excursions in the Alps. The first was to the valley of Hassli, the second to the glaciers of Mont Blanc. In both he was accompanied by his scientific collaborator, M. Desor, whose intrepidity and ardor hardly fell short of his own; by Mr. Dinkel as artist, and by one or two students and friends. These excursions were a kind of prelude to his more prolonged sojourns on the Alps, and to the series of observations carried on by him and his companions, which attracted so much attention in later years. But though Agassiz carried with him, on these first explorations, only the simplest means of investigation and experiment, they were no amateur excursions. On these first Alpine journeys he had in his mind the sketch he meant to fill out. The significance of the phenomena was already clear to him. What he sought was the connection. Following the same comparative method, he intended to track the footsteps of the ice as he had gathered and put together the fragments of his fossil fishes, till the scattered facts should fall into their natural order once more and tell their story from beginning to end. In his explorations of 1838 he found everywhere the same phenomena; the grooved and polished and graven surfaces and the rounded and modeled rocks, often lying far above and beyond the present limits of the glaciers; the old moraines, long deserted by the ice, but defining its ancient frontiers; the erratic blocks, transported far from their place of origin and disposed in an order and position unexplained by the agency of water.