The Rio Branco, the principal tributary of the Negro, is navigable for large craft for about 300 miles from its mouth, but from thence it is interrupted by rapids, only passable by flat-bottomed boats. Its banks are very thickly wooded below the rapids, but above them the country is a wide plain, which affords pasturage to immense herds of cattle. The downward passage from San Joachim, near the sources of the river, to Barra, a distance of 500 miles, may be made in twelve days; but the ascent is very tedious, owing to the rapids and the strong north-easterly winds.
Scarcely any attempt at regular cultivation has yet been made in any part of Amazonas; but the natural productions of its teeming soil are numerous as they are varied and valuable. The forests contain many trees which afford solid and durable timber, and others that furnish excellent cabinet woods, among which may be mentioned the beautiful _muirapinima_, or tortoise-shell wood. There are numerous plants, unknown in Europe, famous for their medicinal uses; and others which produce valuable resins and oils. Wild cotton, with a fine glossy fibre, like silk, grows abundantly, and is used at Guayaquil to stuff mattresses. Some silk manufacturers in France, to whom specimens of this cotton were sent by Mr. Clay, the United States chargé d’affaires at Lima, thought that, mixed with silk, a cheap and pretty fabric might be wove from it.
Santarem, a mile above the mouth of the Tapajos, which is there a mile and a half wide, is the largest town in the province after Pará. In 1849 the population was 6,768, the number of marriages 32, of births 289, of deaths 42; but in this return is included the inhabitants of a large surrounding district. Lieut. Herndon estimated the population of the town alone at about 2,000. There is a church, and two or three primary schools. The situation is picturesque, and there are many agreeable rides in the environs. It is a thriving town, as is shown by the increase in the exports between 1843 and 1846. For three months of the former year the quantity of cocoa exported was 12,808 arrobas, and in the same period of 1846 it was 19,940 arrobas. Sarsaparilla increased from 665 to 4,836 arrobas, pitch from 64 to 933, tobacco from 499 to 3,352, cloves from 226 to 998, cotton from 24 to 226, oil of copaiba from 427 pots to 3,056 pots, and oil of turtle-eggs from 420 to 1,628 pots. Hides and piasaba rope appear in the list for the first time in 1846, the number of the former exported being 664. The trade in farina had considerably decreased, probably owing to the increased importation of flour from the United States. The trade between Santarem and Pará is carried on in schooners of about a hundred tons, of which there were five or six lying off the town when Mr. Herndon was there. The average passage downward is thirteen, and upward twenty-five days.