PHYSICAL GEOGRAPHY OF AFRICA. 87 
The next grand feature in the physical geography 
of Africa, which it is necessary to notice as affecting 
the character of its natural productions, is the great 
extent of desert which occupies various large portions 
of this continent, and which is for the most part 
without elevations and destitute of water. The 
deserts of Africa, however, differ very considerably 
in their particular characters, though they agree in 
the great outline of their features. The Sahara, or 
Great Desert for instance, which occupies the entire 
face of the country between the Atlas mountains on 
the north, and the rich and fertile valleys of the 
Senegal, Gambia, and Niger, on the south, consists 
entirely of low rocky hills, and boundless extents of 
moving sands, parched and pulverized by the intense 
heat of a tropical sun, with here and there an oasis, 
or wadey, as they are called by the Arabs, where a 
patch of verdure and a few date trees surround an 
oceasional spring. In such a country, it may be easily 
supposed, living inhabitants are not to be found; 
and indeed, unless it be a few jerboas or other 
similar animals in the neighbourhood of the wadeys, 
or an occasional flock of gazelles or ostriches on the 
outskirts of the desert, the Sahara may be said to be 
altogether destitute of inhabitants. But the case is 
widely different with respect to the deserts of South 
Africa. The characters of these deserts are altoge- 
ther different from that of the Sahara ; though like 
it consisting of a sandy soil, yet the staple is firmly 
