THE DESERT OF SAHARA. 3 
for the glim trade, situated on the banks of the river, and 
called the stations of the Trarsas and of the Braknas ; who 
are the two most powerful tribes of this part of the Sahara. 
This desert commences at the foot of the Atlas, and ter- 
minates at the Senegal, It is not less extensive from east to 
west, Egypt and the Atlantic being- its boundaries. This 
immense space exhibits no other than a reddish soil, wholly 
unsusceptible of vegetation, except near the springs or wells 
where we find thorny shrubs, purslane, and asclepias ; and 
in the part bordering upon the Senegal, and not far distant 
from the sea, in which are the three large forests of acacias, 
which yield the gum. 
Natural springs, situated at great distances from each 
other, either in the plains or in ravines, and wells formed 
by human hands, sometimes fix, but for a short time only, 
the ever-wandering tribes of Moors. The moving sand which 
covers the greatest part of the Desert, adds to the numerous 
dangers which man incessantly encounters there : for, when 
raised by the winds, it hides the paths, chokes up the springs, 
and even overwhelms whole caravans. 
These accidents are not experienced on the banks of the 
Senegal, nor at a little distance from the sea coast, the only 
part which I have visited ; but the phenomena observed 
there are not less terrible, for whenever the wind blows from 
the east, a kind of sirocco is generally felt on the coast ; the 
horizon assumes the whiteness of a heated furnace ; a devour- 
B 2 
