CONGO, kOn'0, or KONGO (from the Afri can tribe of osicongo). The largest, and, ex cepting the Nile, the longest river of Africa, and in length, volume, and drainage area, one of the great rivers of the earth. It drains most of Cen tral Africa west of longitude 32° E., from latitude 8° N. to 12° S. It has its source in the moun tain region in latitude 9° S. and longitude 32° E., at a point a little southeast of Lake Tan ganyika (Map: Africa, F 5). The lieadstream is the Zambezi River, which flows southwest and enters Lake Bangweolo (altitude, about 3800 feet). The outlet of this lake, known as the Luapula River, flows southwestward, then north ward, and enters Lake Moero (altitude 2900 feet). The outlet of this latter lake, still called the Luapula, flows northwestward and, in lati tude 7° S., longitude 27° E., joins the Lualaba River, which flows north from its source in Katanga, in latitude 12° S., longitude 26° E., to form the Congo by its junction with the Lua pula. About 60 miles north of the confluence of tne Luapula and the Lualaba the Congo is joined by the Lukuga, the outlet of Lake Tanganyika (altitude, 2700 feet). Below this point several minor tributary streams are received by the Congo, mainly from the eastern side, until, at the equator, in longitude 24° 30' E., at a point about 80 miles below Stanley Falls, the Congo is joined by the Lnmami, which has a parallel course on the west. of this point the Congo begins its great bend toward the west. About 60 miles below the entrance of the Lo mam.i, the Arnwimi enters the Congo from the east, and still farther down-stream there join at intervals from the north the rivers Itimbiri, Mongala, Ubangi (which drains the borders of Sudan, and is a very powerful stream), Sanga, Likuala, and 1\lossaka, besides smaller streams; and from the south the Lulongo, Ruki, and Kas sai. Below these, throughout the lower 500 miles
of the river's course, only small tributaries are received. About 300 miles from the mouth of the Congo is Stanley Pool, an enlargement of the river. The mouth is in latitude 6° S., longitude 12° E. The basin of the Congo consists of pla teaus ranging in altitude from 1000 to 3000 feet. It is in the descent from the plateau near the west coast that the impediments to navigation occur. The basin is densely forested with a great variety of broad-leaved trees, and an al most impenetrable undergrowth. The river is navigable for ocean steamers from its mouth to a point about 110 miles up-stream, where navi gation is interrupted by falls and rapids; and also by steamboats from Stanley Pool to Stan ley Falls, for a distance of nearly 1000 miles farther. The length of the navigable wafers of the Congo system is estimated at about 9000 miles. Over 100 steamers were engaged in traffic on the upper Congo waters at the end of the nine teenth century. The completion of the Matadi Railroad hits placed the middle course of the river in communication with its estuary. The Congo has a length of about 2500 miles, and drains an area of more than 1,400,000 square miles.