and the person to whom, as he often declares, he owed his first impulse to the life he led later, he had previously visited England, Holland and Belgium. It was this George Foster, the companion of Captain Cook on his second voyage round the world, who suggested to Humboldt his travels and researches in the tropical world.
As an author young Humboldt had already given proof of far more than ordinary ability. At Göttingen he had written a book on the "Basalts of the Rhine," and in 1792 published a striking essay on the "Fossil Flora of Freiburg." While inspector of mines, employing the discoveries of Galvani, he published two volumes, still frequently consulted, bearing the title, "Über die gereiste Muskel- und Nervenfassen nebst Vermuthengen über den ehemischen Process des Lebens in der Thier- und Pflanzenwelt," Berlin, 1797.
The death of his mother, to whom he was warmly attached, and the increase of his income made it possible for him to carry out longcherished plans for travel and the study of nature in the tropics. Eesigning his position as inspector of mines, he visited Vienna and Paris for special studies and for the purchase of instruments and instruction in their use. In Paris he met Gay-Lussac, Laplace, Arago, Berthollet, and Aimé Bonpland, a young botanist who became his companion in travel and research, and in whom he found the friend and assistant whom he needed. Failing in their attempts to make satisfactory arrangements for explorations in Egypt and Central Africa, the two men finally accepted the protection and assistance of Spain, and decided to devote themselves to the study of the physiognomy, the plant and animal life of the tropical regions of South and Central America and Mexico. At the head of an expedition which in equipment and retinue had hardly been equalled since the days of Alexander the Great the two men sailed from La Coruña in northwestern Spain, June 5, 1799, and landed at Bordeaux, France, on their return home, June 3, 1804. During their absence they had explored Venezuela, ascended the Orinoco 1,800 miles and learned that its head waters are connected with those of the Amazon, had sailed up the Magdalena, settled for a time at Quito and made themselves thoroughly acquainted with the west coast of South America almost to the southern limits of Peru. They had ascended Chimborazo to the height of 19,000 feet, had studied carefully the crater of Cotopaxi and learned all that could be learned at the time concerning the physiognomy of the country. They had studied the forms of life, animal and floral, observed the variations of temperature at different levels above the sea, the arrangements of the mountain chains, the situation and character of volcanoes, active and extinct. They had studied under favorable conditions the celestial phenomena peculiar to the tropical regions and given special attention to the zodiacal light. From the people and their own observation, they had learned all they could learn concerning the country, its civilization and