556’ SANDS OF EGYPT. 
the inclination of the channel is diminished, the rapidity of the 
current is checked, and the deposition of the slime it holds in 
suspension consequently promoted. Thus the winds and the 
water, moving in contrary directions, join in producing a com- 
mon effect. 
The sand, blown over the Delta and the cultivated land 
higher up the stream during the inundation, is covered or 
mixed with the fertile earth brought down by the river, and 
no serious injury is sustained from it. That spread over the 
same ground after the water has subsided, and during the 
short period when the soil is not stirred by cultivation or coy- 
ered by the flood, forms a thin pellicle over the surface as far 
as it extends, and serves to divide and distinguish the succes- 
sive layers of slime deposited by the annual inundations. The 
particles taken up by the wind on the sea-beach are borne on- 
ward, by a hopping motion, or rolled along the surface, until 
they are arrested by the temporary cessation of the wind, by 
vegetation, or by some other obstruction, and they may, in 
process of time, accumulate in large masses, under the lee of 
rocky projections, buildings, or other barriers which break the 
force of the wind. 
In these facts we find an important element in the explanation 
of the sand drifts, which have half buried the Sphinx and so 
many other ancient monuments in that part of Egypt. These 
drifts, as I have said, are not wholly from the desert, but in 
large proportion from the sea; and, as might be supposed from 
the distance they have travelled, they have been long in gather- 
ing. While Egypt was a great and flourishing kingdom, 
measures were taken to protect its territory against the encroach- 
ment of sand, whether from the desert or from the Mediter- 
ranean; but the foreign conquerors, who destroyed so many of 
its religious monuments, did not spare its public works, and the 
process of physical degradation undoubtedly began as early as 
the Persian invasion. The urgent necessity, which has com- 
pelled all the successive tyrannies of Egypt to keep up some of 
the canals and other arrangements for irrigation, was not felt 
