YOUR LOUIS.
The story of this expedition has been told in the partly scientific, partly personal diary published after Agassiz's return, under the title of "A Journey in Brazil," and therefore a full account of it here would be mere repetition. He was absent sixteen months. The first three were spent in Rio de Janeiro, and in excursions about the neighborhood of her beautiful bay and the surrounding mountains. For greater efficiency and promptness he divided his party into companies, each working separately, some in collecting, others in geological surveys, but all under one combined plan of action.
The next ten months were passed in the Amazonian region. This part of the journey had the charm of purely tropical scenery, and Agassiz, who was no less a lover of nature than a naturalist, enjoyed to the utmost its beauty and picturesqueness. Much of the time he and his companions were living on the great river itself, and the deck of the steamer was by turns laboratory, dining-room, and dormitory. Often, as they passed close under the banks of the river, or between the many islands which break its broad expanse into narrow channels, their improvised working room was overshadowed by the lofty wall of vegetation, which lifted its dense mass of trees and soft drapery of vines on either side. Still more beautiful was it when they left the track of the main river for the water-paths hidden in the forest. Here they were rowed by Indians in "montarias," a peculiar kind of boat used by the natives. It has a thatched hood at one end for shelter from rain or sun. Little sun penetrates, however, to the shaded "igarape" (boat-path), along which the montaria winds its way under a vault of green. When traveling in this manner, they stopped for the night, and indeed sometimes lingered for days, in Indian settlements, or in the more secluded single Indian lodges, which are to be found on the shores of almost every lake or channel. In this net-work of fresh waters, threading the otherwise impenetrable woods, the humblest habitation has its boat and landing-place. With his montaria and his hammock, his little plantation of bananas and mandioca, and the dwelling, for which the forest about him supplies the material, the Amazonian Indian is supplied with all the necessities of life.
Sometimes the party were settled, for weeks at a time, in more civilized fashion, in the towns or villages on the banks of the main river, or its immediate neighborhood, at Manaos, Ega, Obydos, and elsewhere. Wherever they sojourned, whether for a longer or a shorter time, the scientific work went on uninterruptedly. There was not an idle member in the company.
From the time he left Rio de Janeiro, Agassiz had the companionship of a young Brazilian officer of the engineer corps, Major Coutinho. Thoroughly familiar with the Amazons and its affluents, at home with the Indians, among whom he had often lived, he was the pearl of traveling companions as well as a valuable addition to the scientific force. Agassiz left the Amazonian valley in April, and the two remaining months of his stay in Brazil were devoted to excursions along the coast, especially in the mountains back of Ceara, and in the Organ mountains near Rio de Janeiro.
From beginning to end this journey fulfilled Agassiz's brightest anticipations. Mr. Thayer, whose generosity first placed the expedition on so broad a scientific basis, continued to give it his cordial support till the last specimen was stored in the Museum. The interest taken in it by the Emperor of Brazil, and the liberality of the government toward it, also facilitated all Agassiz's aims and smoothed every difficulty in the path. On starting he had set before himself two subjects of inquiry. These were, first, the fresh-water fauna of Brazil, of the greater interest to him, because of the work on the Brazilian Fishes, with which his scientific career had opened; and second, her glacial history, for he believed that even these latitudes must have been, to a greater or less degree, included in the ice-period. The first three months spent in Rio de Janeiro and its environs gave him the key to phenomena connected with both these subjects, and he followed them from there to the head-waters of the Amazons, as an Indian follows a trail. The distribution of life in the rivers and lakes of Brazil, the immense number of species and their local circumscription, as distinct faunae in definite areas of the same water-basin, amazed him; while the character of the soil and other geological features confirmed him in his preconceived belief that the glacial period could not have been less than cosmic in its influence. He was satisfied that the tropical, as well as the temperate and arctic regions, had been, although in a less degree, fashioned by ice.
Just before leaving the United States he received a letter of friendly farewell from Charles Sumner, and his answer, written on the Rio Negro, gives some idea of the conditions under which he traveled, and of the results he had obtained. As the letters explain each other, both are given here.
FROM CHARLES SUMNER.
WASHINGTON, March 20, 1865.