In the latter part of 1790, Humboldt went to Hamburg, to enter the School of Commerce. He wished to study political economy further, and to learn practical book-keeping. He wrote to a friend: "I am contented with my mode of life at Hamburg, but not happy, less happy even than at Göttingen, where the monotony of my existence was relieved by the society of one or two friends and the vicinity of some moss-grown mountains. I am, however, always contented when I feel that I am accomplishing the purpose I have in view.... My leisure hours are occupied with geology and botany.... In addition, I have begun to learn Danish and Swedish."
To Wegener he writes: "I have made considerable progress in general information, and I am beginning to be somewhat more satisfied with my attainments. I worked very hard at Göttingen, but all I have learned makes me feel only the more keenly how much remains still to know. My health suffered severely, but improved somewhat during my journey with Foster; yet even here I continue so closely occupied that I find it difficult to spare myself. There is an eager impulse within me, which often carries me, I fear, beyond the bounds of reason; and yet such impetuosity is always necessary to insure success."
The "eager impulse" was a sure indication of something to be accomplished by and by. Success does not come with half-hearted effort; it comes only through a force and persistence that will allow no barriers between us and the goal.
At Easter, 1791, Humboldt left Hamburg and hastened to the famous School of Mines at Freiberg, to study under the celebrated Werner. Here, as ever, he attached one ardent friend to himself, Freiesleben, a student in geology. Here every moment was occupied. He studied the works of the French chemists; Guyton de Moreau, Fourcroy, Lavoisier, and Berthollet. He was daily in the mines, from six o'clock till twelve. He crowded six lectures into each afternoon. He made a study of the vegetation of that lower world, from which the sunlight is ever excluded, and the results were used later in his comprehensive work, "Flora Subterranea Fribergensis." He wrote articles for several scientific journals. A busy life, indeed, for the young man of twenty-two!