THE DESKKT OF SAHARA. 511 



as the expanse from which they emerge. But the plains also have a different char- 

 acter 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 traveler 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 Sahara. Often also the plain 

 is rent by deep chasms, or hollowed into vast basins. In the former, particularly on 

 the northern limits of the desert, the rain descending from the gulleys of the Atlas, 

 sometimes forms streams, which are soon swallowed up by the thirsty sands, or dried 

 by the burning sunbeams. 



The deeper basins of the Sahara are frequently of great extent, and sometimes con- 

 tain valuable deposits of salt Wherever perennial springs rise from the earth, or 

 wherever it has been possible to collect water in artificial wells, green oases, often 

 many days' journey apart from each other, break the monotony of the desert. They 

 might be compared with the charming islands that stud the vast solitudes of the South 

 Sea ; but they do not appear, like them, as elevations over surrounding plains of sea, 

 but as depressions, where animals and plants find a sufficient supply of water, and a 

 protection, not less necessary, against the terrific blasts of the desert. 



A wonderful luxuriance of vegetation characterizes these oases of the wilderness. 

 Under and between the date-palms, that are planted about six paces apart, grow apricot 

 and peach trees, pomegranates and oranges, the henneh, so indispensable to oriental 

 beauty ; and even the apple-tree, the pride of European orchards. The vine twines 

 from one date-palm to another, and every spot susceptible of culture bears grain, par- 

 ticularly dourrah or barley, and also clover and tobacco. With prudent economy the 

 villages are built on the borders of the oases on the unfruitful soil, so that not a foot 

 of ground susceptible of culture may be lost. 



The vast tracts of sterile sand, where not even the smallest plants take root, and 

 which might be called the "desert of the desert," present the greatest conceivable 

 contrast to its green oases. With the vegetable world the animal kingdom likewise 

 disappears, and for days the traveler pursues his journey without meeting with a single 

 quadruped, bird, or insect. Nowhere are the transitions of light and shade more ab- 

 rupt than in the desert, for nowhere is the atmosphere more thoroughly free of all 

 vapors. The sun pours a dazzling light on the ground, so that every object stands 

 forth with wonderful clearness, while all that remains in the shade is sharply defined, 

 and appears like a dark spot in the surrounding glare. 



The stillness of these wastes is sometimes awfully interrupted by the loud voice of 

 the khamsin or simoom. The crystal transparency of the sky is veiled with a hazy dim- 

 1 ness. The wind rises and blows in intermittent gusts, like the laborious breathing of 

 a feverish patient. Gradually the convulsions of the storm grow more violent and 

 frequent ; and although the sun is unable to pierce the thick dust-clouds, and the 

 shadow of the traveler is scarcely visible on the ground, yet so suffocating is the heat, 

 that it seems to him as if the fiercest rays of the sun were scorching his brain. The dun 

 atmosphere gradually changes to a leaden blackness ; the wind becomes constant ; and 

 even the camels stretch themselves upon the ground and turn their backs to the whirl- 

 ling sand-storm. At night the darkness is complete ; no light or fire burns in the tents, 

 which are hardly able to resist the gusts of the simoom. Silence reigns throughout 

 the whole caravan, yet no one sleeps ; the bark of the jackal or the howl of the hyena 



I 



