sluggish rivers as the Juba, Tana, Lufiji, and Rovuma. But south of the great central lacustrine plateaux the Zambezi, whose furthest headstreams rise near the west coast, drains a vast tract of country estimated at about 750,000 square miles, or nearly three times the size of France. In volume it ranks third amongst African rivers, but in length fourth only. Still farther south the Limpopo has also a considerable discharge; whereas the Orange, whose basin exceeds 400,000 square miles in extent, contributes to the South Atlantic very little of the rainfall collected in
Fig. 3.—Outflow of Lake Nyanza, according to Speke.
Scale 1 : 1,000,000.
the gorges of its upper course. The Kunene and Koanza, which follow from south to north, although more copious, have still but a slight volume compared with their respective areas of drainage. The same may be said of the Ogowé, which rises in the peninsular tract formed by the great bend of the Congo east of equatorial Guinea.
The Niger, or "Nile of the Blacks," forms with the Nile, Congo, and Zambezi, one of the four great arteries of Africa. Even down to the beginning of this century many geographers still supposed that the Nile and the Niger mingled their