Europe becoming too small for his genius, he visited the tropics in the new world, where, in the most circumscribed limits, he could find the greatest number of plants, of animals, and the greatest diversity of climate, that he might ascertain the laws governing the production and distribution of plants, animals and men, and the effects of climate upon them all. He sailed along the gigantic Amazon--the mysterious Orinoco--traversed the Pampas--climbed the Andes until he stood upon the crags of Chimborazo, more than eighteen thousand feet above the level of the sea, and climbed on until blood flowed from his eyes and lips. For nearly five years he pursued his investigations in the new world, accompanied by the intrepid Bonpland. Nothing escaped his attention. He was the best intellectual organ of these new revelations of science. He was calm, reflective and eloquent; filled with a sense of the beautiful, and the love of truth. His collections were immense, and valuable beyond calculation to every science. He endured innumerable hardships, braved countless dangers in unknown and savage lands, and exhausted his fortune for the advancement of true learning. Upon his return to Europe he was hailed as the second Columbus; as the scientific discoverer of America; as the revealer of a new world; as the great demonstrator of the sublime truth that universe is governed by law. I have seen a picture of the old man, sitting upon a mountain side--above him the eternal snow; below, smiling valley of the tropics, filled with vine and palm. His chin upon his breast, his eyes deep, thoughtful and calm, his forehead majestic--grander than the mountain upon which he sat. "Crowned with the snow of his whitened hair," he looked the intellectual autocrat of this world. Not satisfied with his discoveries in America, he crossed the steppes of Asia, the wastes of Siberia, the great Ural range, adding to the knowledge of mankind at every step. His energy acknowledged no obstacle, his life knew no leisure; every day was filled with labor and with thought. He was one of the apostles of science, and he served his divine master with a self-sacrificing zeal that knew no abatement--with an ardor that constantly increased, and with a devotion unwavering and constant as the polar star. In order that the people at large might have the benefit of his numerous discoveries, and his vast knowledge, he delivered at Berlin a course of lectures, consisting of sixty-one free addresses, upon the following subjects: Five upon the nature and limits of physical geography. Three were devoted to a history of science. Two to inducements to a study of natural science. Sixteen on the heavens. Five on the form, density, latent heat, and magnetic power of the earth, and to the polar light. Four were on the nature of the crust of the earth, on hot springs, earthquakes and volcanoes. Two on mountains, and the type of their formation.