246 
GRAPHIC DESCRIPTION OF AFRICA. 
noxious serpents which were so numerous in that country; others 
that there was supposed to be some analogy between the plumage of 
the bird and one of the phases of the moon; while a third opinion 
is that the birds were regarded with favor, because, their annual 
migration into Egypt taking place at the period of the rising of the 
Nile, they were considered as the harbingers of that event. 
A glowing description of tropical scenery finds a striking con¬ 
trast of the account given of the African desert, and the perils 
which often overtake travelers who attempt to cross it. 
TERRIFIC SAND STORMS, 
The plain of Sahara is the great typical desert. Its name comes 
from an Arabic word, which means the plain. Not that the great 
desert is by any means an unbroken plain, or destitute of great 
variety in its physical characteristics. The true sandy desert occu¬ 
pies but a relatively small portion of the space marked upon our 
maps as the desert of Sahara; and even upon the surface of this 
“true’’ desert the distribution of sand is very unequal. The stratum 
of the sand in some parts is so thin that the underlying limestone is 
visible through it. The sandy region attains its greatest extent in 
the Libyan desert, and masses of sand still drift in from the Medi¬ 
terranean, to settle down upon a bed which in a recent period was 
buried beneath the waves of the sea. These sand floods extend 
westward to Tripoli. Near that town the sandy stretches are varied 
by plantations of palm trees and fields of corn; true deserts of 
yellow sand, passing like a yellow ribbon from west to east, between 
fields of wheat and barley. 
The western Mongolian desert contains plains of sand perfectly 
corresponding with those of the Sahara and the Arabian desert. 
Mounds of loose sand are blown together and scattered again by 
the wind: a mere breeze is enough to wipe out all trace of a long 
caravan crossing the waste. The sand is so extremely fine and 
light, that in sudden storms of wind trenches of thirty or forty 
feet deep are hollowed out, and swelling waves are raised like those 
of the Libyan desert, making the journey tedious and difficult to 
the camels as they cross the shifting plain. 
