TANGANYIKA, tfin'gin-yelka. A large lake in Central Africa, extending from latitude 3° 16' to 8° 48' S., and from longitude 29° 20' to 31° 20' E. (Map: Africa, H 5). Its northern end is 175 miles southwest of the Victoria Nyanza. and its southern end 190 miles northwest of Lake Nyassa. It lies in the western branch of the Great Rift Valley (q.v.), which is interrupted at the south end of the lake by a plateau, but continued farther to the southeast as the basin of Lake Nyassa. Tanganyika extends in a north and south direction, with a length of 400 miles and a breadth of 20 to 40 miles. Its area is estimated at over 12.000 square miles. Its basin, which includes a narrow strip of fertile lowland along either shore, is bounded by the high and steep sides of the Rift Valley. which in some places form precipitous rocky cliffs, and reach a height of 4200 feet above the level of the lake, which is 2700 feet above the sea. The depth is very great, ranging in the greater portion from 500 to over 2000 feet, and the lake is remarkably free from shoals, reefs, or islands. There are, however, floating islands of vegetation, the shores being often very densely forested with palms. Navigation is also rendered dangerous by severe hurricanes and tornadoes to which the basin is subject. The lake is fed by numerous small streams from the surrounding plateau, and dis eharges into the Congo through the Lukuga, which leaves it near the middle of the western shore. This discharge. however. is intermittent,
and the level of the lake is subject to periodic fluctuAions, each of which may range over a series of years. The fall of the lake level in re cent times has amounted to two feet annually. Though the water is, as a whole, fresh, it has in some portions a tendency to become brackish. The fauna of the lake is very rich and peculiarly interesting. Besides the usual fresh-water fish, crocodiles, and hippopotamuses, all of which are abundant, there are a number of peculiar iso lated groups of deep-water mollusks and crabs which are asserted to be of marine origin. This fact points to the theory that in Jurassic or Cretaceous times the lake was an arm of the sea which became isolated by subsequent up heavals.
Politically the west shore belongs to the Congo Free State, the east shore to German East Afri ca, and the south shore to the British colony of Rhodesia. All three powers have trading and mission stations on the shores, and several steamers have been launched on the lake. Of the numerous native towns the largest is Ujiji, on the east shore. Lake Tanganyika was discovered in 1858 by Burton and Speke, and later explored by Livingstone, Cameron, Stanley, and others. Consult Peters, Das deutsch-ostrafrikanischc Schutzgcbiet (Munich, 1895).