XV 



The Continental Area 291 



Mountains near the angle of the Gulf of Guinea, and slopes 

 down very gradually inland. Its western extension is pierced 

 by the great River Niger, flowing into the Gulf of Guinea. 

 The second or Central Ridge runs from the equator toward 

 the Atlas Range across the northern high plain. Uniting 

 with the Coast Ridge in latitude 5 N. and again in 20 N. 

 it forms two great basins, of which the southern] or equa- 

 torial is, on the average, higher, and the northern lower, 

 than 1000 feet. The third or Red Sea Ridge runs along 

 the Red Sea coast from the northern extremity of the 

 Great Plateau. A very remarkable hollow furrows the 

 whole length of the Great Plateau for nearly 2000 miles 

 from north to south, and contains a succession of four great 

 lakes connected with three distinct river systems. These 

 are Lakes Albert and Albert Edward draining to the Nile 

 in the north, Lake Tanganyika attached to the Congo in 

 the centre, and Lake Nyasa united to the Zambesi in the 

 south. 



375- Nile River System. Lake Albert collects the 

 head-waters of the Nile, receiving the Semliki River from 

 Lake Albert Edward lying at the base of Ruwenzori, and 

 fed by the ceaseless torrents from that mountain. It also 

 receives at the northern extremity the outflow of the largest 

 lake in Africa, the Victoria Nyanza, which is situated on a 

 higher part of the plateau east of the Great Hollow at an 

 elevation of 3300 feet. This branch, the Victoria Nile, is 

 broken by a succession of falls as it descends the steep 

 edge of the plateau. From Lake Albert the White Nile 

 flows northward to the Mediterranean . across the desert 

 which stretches between the slopes of the Red Sea Ridge 

 and the Central Ridge, receiving many tributaries from both. 

 The rainy heights of Abyssinia send down the Blue Nile 

 and the Atbara, on which the periodical flooding of the 

 Nile depends, but after the junction of the latter stream the 

 Nile flows in three great bends across the parched low plain 

 to its delta ( 325) without receiving another drop of water, 

 and subject to continual evaporation ( 318). The six 

 famous cataracts which occur in its lower course are pro- 

 duced by its bed crossing bars of hard rock, and they thus 



