STEPPES AND DESERTS. 9 



passed over heat-radiating continents. The venerable father 

 of history, Herodotus, so long insufficiently appreciated, has 

 in the true spirit of a comprehensive observer of nature, de- 

 scribed all the deserts of Northern Africa, Yemen, Kerman, 

 and Mekran (the Gedrosia of the Greeks), as far even as 

 Mooltan in Western India, as one sole connected sea of 

 sand (21). 



To the action of hot land winds, may be associated in 

 Africa, as far as we know, a deficiency of large rivers, of 

 forests that generate cold by exhaling aqueous vapour, and 

 of lofty mountains. The only spot covered with perpetual 

 snow is the western portion of Mount Atlas (22), whose narrow 

 ridge, seen laterally, appeared to the ancient navigators 

 when coasting the shore, as one solitary and aerial pillar of 

 heaven. This mountain range extends eastward to Dakul, 

 where the famed Carthage, once mistress of the seas, lies in 

 crumbling ruins. This range forms a far extended coast-line 

 or Gaetulian rampart, which repels the cool north winds and 

 with them the vapours rising from the Mediterranean. 



The Mountains of the Moon, Djebel-al-Komr (23), fabu- 

 lously represented as forming a mountainous parallel between 

 the elevated plain of Habesch an African Quito and the 

 sources of the Senegal, were supposed to rise above the lower 

 sea line. Even the Cordilleras of Lupata, which skirt the 

 eastern coast of Mozambique and Monomotapa, in the same 

 manner as the Andes bound the western shores of Peru, are 

 covered with eternal snow in the gold districts of Machinga 

 and Mocanga. But these mountains, abundantly watered, are 

 situated at a considerable distance from the vast desert which 

 extends from the southern declivity of the chain of Atlas to 

 the Niger, whose waters flow in an easterly direction. 



Possibly, these combined causes of aridity and heat would 

 have proved insufficient to convert such large portions of the 

 African plains into a dreary waste, had not some convulsion 

 of nature as for instance the irruption of the ocean on 



