A SINGULAR EFFECT. 131 



in the desert, vanish completely. You must excavate the soil to 

 obtain a supply of water, and when found, it is brackish. Frequently 

 the beds unite, forming basins of greater or less extent and depth, which 

 fill themselves at the close of the winter floods, and a few of which 

 preserve, even in the winter season, a certain quantity of water. 

 Elsewhere, the soil is only humid, thanks to the abundance of salt, 

 which retains the moisture. In such places numerous slimy marshes 

 occur, where the traveller may not adventure without peril. But 

 in general the surface is dry, cracked, cloven, and completely 

 parched. 



The Desert of Erosion is not completely inhabited. At inter- 

 vals you meet with a few squalid villages, and a multitude of 

 camel' s-skin tents are scattered like black spots over the yellow 

 or grayish plains, on the borders of the chotts or scanty water- 

 courses. Herds of goats and flocks of sheep wander in the valleys, 

 browsing on the rare short grass. Columns of smoke arise from 

 the Arab bivouacs, and the women of the Sahara group themselves 

 around the wells and springs to fill the water-bags with which 

 they load their asses. 



When, from the summit of the rocks which fence round and bristle 

 over the Desert of Erosion, we perceive for the first time the Desert of 

 Sand, the impression is very similar to that which we derive from 

 the sight of ocean. M. Martins had already become sensible of this 

 peculiar effect when, from the Col de Sfa, he had gazed down 

 upon the Desert of the Plateaux. " A grand circular arch," he says, 

 " extended before us, bounding a violet surface, smooth as the sea, 

 and blending at the horizon with the azure of heaven ; it was the 

 Sahara. The arc eastward rested against the chain of the Aures ; 

 westward, against that of the Zibans, some of whose offshoots, in the 

 neighbourhood of Biskra, arose like reefs upon that sea which seemed 

 to have been frozen suddenly into immobility. The actual sea ever 

 trembles and shivers on the surface ; a light wavering, imperceptible 

 to the eye, propels towards the shore the expiring wave, fringed with 

 a border of foam. Here, nothing like this may be seen ; it is a 



