Baron Humboldt, in the opening of his Cosmos, vol. ii., recalls the lessons of experience, which tell us how often impressions received by the senses from circumstances, seemingly accidental, have so acted on the youthful mind as to determine the whole direction of the man's course through life. Childish pleasure, in the form of countries and of seas, as delineated in maps; the desire to behold those southern constellations which have never risen in our horizon; the sight of palms and of the cedars of Lebanon, figured in a pictorial Bible, may have implanted in the spirit the first impulse to travel in distant lands.

"If I might (says Humboldt) have recourse to my own experience, and say what awakened in me the first beginnings of an inextinguishable longing to visit the tropics, I should name George Forster's descriptions of the islands of the Pacific—paintings, by Hodge, in the house of Warren Hastings, in London, representing the banks of the Ganges—and a colossal dragon-tree in an old tower of the Botanic Gardens at Berlin."