226 PHYSICAL GEOGRAPHY. 



which especially applies to an immense domain extending on both sides of the tropic of 

 Cancer, but having its main direction from west to east, and including more than a fifth 

 part of the whole of that territory. This is the Sahara-bela-ma of the Arabs, or desert 

 without water, called also the Bahar-hela-ma, or ocean without water. Upon a large 

 space of this district there is neither rain nor dew, to awaken in the glowing bosom of the 

 earth the germs of vegetable life. From the west coast of Africa, and between Morocco 

 on the north and the Senegal river on the south, this wilderness extends easterly to the 

 Red Sea, contracted towards the west by a projecting part of the kingdom of Fezzan, 

 and interrupted on the east by the narrow valley of the Nile. It embraces a space of 

 more than 46 of longitude and 15 of latitude, or a length of 3000 miles by a breadth of 

 1000. A large extent of the Sahara is a dead level ; but low sand hills, wadys or valleys, 

 and projecting rocks are frequent. " Now the naked rock " says Humboldt, describing its 

 characteristics, "appears to view perfectly smooth and level, which the traveller may 

 pass over for days together without meeting even a grain of sand, where one sees only 

 the heaven above and the hard^stone pavement beneath; now we behold a flat plain 

 covered with rolled pebbles, here and there intersected with ravines and valleys extending 

 to about thirty feet below the surface ; and now an ocean of sand presents itself, frequently 

 containing so large a quantity of salt, that whole tracts appear coated with it, and 

 resemble fields of ice. Occasionally spots of verdure are found, known under the name 

 of oases, which display palm trees and springs of water." The Egyptians, says Strabo, 

 give the name of oases to inhabited spots surrounded by vast deserts of sand, and 

 resembling islands in the sea. There are, he states, many such in Lybia, while three 

 border on Egypt, and are referred to that country. Modern discovery has, however, made 

 us acquainted with several of these isles of the African ocean of sand, which are rich in 

 streams and vegetation. In the western part of Fezzan, in a hollow surrounded by 





Lake of Mandia. 



rocks, lies the small lake of Mandia, celebrated for the occurrence of Trona, or pure 

 natron (soda). Oudney and Clapperton, on their memorable expedition from Tripoli, 

 visited this lake. Clapperton, as Oudney tells us, was sitting on the top of a high sand 

 hill, and so pleased with the view, that he called out several times to his companion to 

 dismount from his camel to enjoy the treat. The appearance was beautiful. There was a 

 deep sandy valley, containing only two large groves of date trees, enclosing a fine lake. 

 The contrast between the bare lofty sand hills, and the two insulated spots, was the great 

 cause of the sensation of beauty. There is something pleasing in a lake surrounded with 

 vegetation ; but when every other object within the sphere of vision is dreary, the scene 

 will become doubly so. No doubt the oases in general owe much of their reputation to 

 the contrast they form with the absolute barrenness of the desert. With the exception 

 of these spots, the Sahara is uninhabitable for man; and it 'is only at -periodic times 

 that it is traversed by the trading caravans, which proceed across it from Tafilet to 

 Timbuctoo, and from Fezzan to Bornou. These are bold undertakings, the practicability 

 of which depends upon the life of the camel the ship of the desert, as the animal is 



