460 
THE SUEZ CANAL. 
Another circumstance is necessary to be considered in esti¬ 
mating the danger to which the arable lands ot Egypt are 
exposed. The prevailing wind in the valley of the JNile and 
its borders is from the north, and it may be said without 
exaggeration that the north wind blows tor three quarters ot 
the year.* The effect of winds blowing up the valley is to 
drive the sands of the desert plateau which border it, in a 
direction parallel with the axis of the valley, not transversely 
to it; and if it ran in a straight line, the north wind would 
carrv no desert sand into it. There are, however, both curves 
and angles in its course, and hence, wherever its direction 
deviates from that of the wind, it might receive sand drifts 
from the desert plain through which it runs. But, in the 
course of ages, the winds have, in a great measure, bared the 
projecting points of their ancient deposits, and no great accu¬ 
mulations remain in situations from which either a north or a 
south wind would carry them into the valley.f 
The Suez Canal. 
These considerations apply, with equal force, to the sup¬ 
posed danger of the obstruction of the Suez Canal by the drift- 
Arabia, and the testimony of the Bedouins he consulted, are to the same 
purpose. The dangers of the simoom are of a different character, though 
they are certainly aggravated by the blinding effects of the light particles 
of dust and sand borne along by it, and by that of the inhalation of them 
upon the respiration. 
* In the narrow valley of the Kile, bounded as it is, above the Delta, by 
high cliffs, all air currents from the northern quarter become north winds, 
though of course varying in partial direction, in conformity with the sinu¬ 
osities of the valley. Upon the desert plateau they incline westward, and 
have already borne into the valley the sands of the eastern banks, and 
driven those of the western quite out of the Egyptian portion of the Kile 
basin. 
t “ The Korth African desert falls into two divisions: the Sahel, or 
western, and the Sahar, or eastern. The sands of the Sahar were, at a 
remote period, drifted to the west. In the Sahel, the prevailing east 
winds drive the sand-ocean with a progressive westward motion. The 
eastern half of the desert is swept clean.”— Kattmann, Geognosie, ii, p. 1173. 
