LIMITS OF THE SAHARA 69 



the fertile coast-lands of Barbary and intercept the winter 



rains, the steppes covered with sedgy pale green Alfa-grass, and 



dotted here and there with grey wormwood and rosemary shrubs 



or dark-leaved pistacias, only gradually merge into the naked 



wilderness; and in the south no geographer is able as yet to 



draw the line between the rai nless Sa hara and the well-watered 



1 lands of Nigritia, No European traveller has ever followed the 



' southern limits of the desert from east to west, nor is its interior 



« known except only along a few roads, traced for many a cen- 



[ tury by the wandering caravans. From Tafilet to Timbuctoo, 



', or from Murzuk to Bornu, the long train traverses the desert 



to exchange cotton-goods, silk, iron, glass, pearls, and other 



1 articles of northern industry, for the ivory, gold-dust, camels, 



slaves, ostrich-feathers, and tanned hides of the wealthy Soudan; 



t and annually from the oases of the Touat, situated to the south 



: of Algeria, a stream of pilgrims flows to the east, and growing 



as it advances through the Fezzan, Augila, and Siwah, at length 



[ reaches Kosseir on the Red Sea, where it finds vessels waiting 



to transport it to Djedda, situated on the opposite shore, in the 



). vicinity of Mecca the Holy. 



; In general the desert may be said to extend in breadth from 

 I the thirty-ninth to the seventieth degree of northern latitude; 

 but while in many parts it passes these bounds, in others fruit- 

 ful districts penetrate far into its bosom, like large peninsulas 

 or promontories jutting into the sea. 



Until within the last years, it was supposed to be a low plain, 

 [jartly situated even below the level of the ocean ; but the 

 journeys of Earth, Overweg, and Vogel have proved it, on the 

 contrary, to be a high table-land, rising 1 000 or ?000 feet above 

 the sea. Nor is it the uniform sand- plain which former de- 

 scriptions led one to imagine ; for it is frequently traversed by 

 chains of hills, as desolate and wild as the expanse from which 

 they emerge. But the plains also have a different character in 

 various parts : sometimes over a vast extent of country the 

 ground is strewed with blocks of stone or small boulders, no 

 less fatiguing to the traveller than the loose drift sand, which, 

 particularly in its western part (most likely in consequence of 

 ''\[ the prevailing east winds), covers the dreary waste of the 

 >^ahara. Often also the plain is rent by deep chasms, or hol- 



F 3 



