104 National Geographic Magazine. 



the Desert of Kalahai-i on the south. On the edge of these 

 deserts are Lake Chad on the north, and Lake Ngami on the 

 south. North of the Desert of Sahara, and south of the Desert 

 of Kalahari, there is an abundant rainfall, a healthy climate, and 

 fertile soil. Morocco, Algiers, and Tripoli, on the Mediterra- 

 nean, are in the north region ; and Zulu-Land, the Orange Free 

 State, and Cape Colony, in the corresponding region of the south. 



That portion of Africa north of the equator is three or four 

 times greater than that south, and the Sahara Desert and Lake 

 Chad are several times greater than the Kalahari Desert and 

 -Lak§ Ngami. The Sahara Desert, the waterless ocean three times 

 as larsre as the Mediterranean, extends from the Atlantic Ocean 

 to the Red Sea, broken only by the narrow valley of the Nile. 

 It is interspersed with oases, with the valleys of many dry 

 streams, and with some mountains 8,000 feet. It has the hottest 

 climate in the world. Travelers tell us, that, in upper Egypt and 

 Nubia, eggs may be baked in the hot sands ; that the soil is like 

 fire, and the wind like a flame ; that in other parts of the desert 

 the sand on the rocks is sometimes heated to 200° in the day-time, 

 while in the following night the thermometer falls below freez- 

 ing-point. In crossing the desert the traveler will hardly need 

 a guide, for the road is too clearly marked by the bones and skel- 

 etons that point the M^ay. 



Lake Chad receives the drainage of a considerable area of 

 country. In the dry season it has no outlet, and is then about 

 the size of Lake Erie. In the wet season it is said to be five 

 times as large. Its level rises by twenty or thirty feet until it 

 overflows into the Desert of Sahara, forming a stream which 

 runs northward for several hundred miles, and is finally lost in a 

 great depressed plain. In the southern part of Africa the level 

 of Lake Ngami rises and falls in a similar manner. 



Through the great equatorial belt runs the Kongo, one of the 

 wonderful rivers of the world. The more we know of this river 

 and its tributaries, the more we are impressed by its greatness 

 and importance. Its principal source is in the mountain-range 

 which separates Lake Nyassa from Lake Tangan;^lka, between 

 300 and 400 miles west of the Indian Ocean ; thence it runs 

 southerly through Lake Bangweolo. On leaving this lake, it 

 takes a north-west course, running from 12° south latitude to 2° 

 north latitude, thence running south-westerly to the ocean, nearly 

 3,000 miles. The river Sankuru, its principal tributary, empties 



