. . .It was not without deep emotion that we read your letter of the 14th, and I easily understand that, anticipating its effect upon us all, you have deferred writing as long as possible. Yet you were wrong in so doing; had we known your projects earlier we might have forestalled for you the choice of M. de Humboldt, whose expedition seems to us preferable, in every respect, to that of M. Ackermann. The first embraces a wider field, and concerns the history of man rather than that of animals; the latter is confined to an excursion along the sea-board, where there would be, no doubt, a rich harvest for science, but much less for philosophy. However that may be, your father and mother, while they grieve for the day that will separate them from their oldest son, will offer no obstacles to his projects, but pray God to bless them. . . The subjoined letter of about the same date from Alexander Braun to his father tells us how the projects so ardently urged upon his parents by Agassiz, and so affectionately accepted by them, first took form in the minds of the friends. BRAUN TO HIS FATHER. MUNICH, February 15, 1829. . . .Last Thursday we were at Oken's. There was interesting talk on all sorts of subjects, bringing us gradually to the Ural and then to Humboldt's journey, and finally Oken asked if we would not like to go with Humboldt. To this we gave warm assent, and told him that if he could bring it about we would be ready to start at a day's notice, and Agassiz added, eagerly, "Yes,--and if there were any hope that he would take us, a word from you would have more weight than anything." Oken's answer gave us but cold comfort; nevertheless, he promised to write at once to Humboldt in our behalf. With this, we went home in great glee; it was very late and a bright moonlight night. Agassiz rolled himself in the snow for joy, and we agreed that however little hope there might be of our joining the expedition, still the fact that Humboldt would hear of us in this way was worth something, even if it were only that we might be able to say to him one of these days, "We are the fellows whose company you rejected." With this hope the friends were obliged to content themselves, for after a few weeks of alternate encouragement and despondency their bright vision faded. Oken fulfilled his promise and wrote to Humboldt, recommending them most warmly. Humboldt answered that his plans were conclusively settled, and that he had chosen the only assistants who were to accompany him,--Ehrenberg and Rose.