All who journey on the Nile, whether in commerce or war, will pay their
tribute of respect and gratitude; for the great river has befriended all
races and every age. Through all the centuries it has performed the annual
miracle of its flood. Every year when the rains fall and the mountain
snows of Central Africa begin to melt, the head-streams become torrents
and the great lakes are filled to the brim. A vast expanse of low, swampy
lands, crossed by secondary channels and flooded for many miles, regulates
the flow, and by a sponge-like action prevents the excess of one year
from causing the deficiency of the next. Far away in Egypt, prince,
priest, and peasant look southwards with anxious attention for the
fluctuating yet certain rise. Gradually the flood begins. The
Bahr-el-Ghazal from a channel of stagnant pools and marshes becomes a
broad and navigable stream. The Sobat and the Atbara from dry
watercourses with occasional pools, in which the fish and crocodiles are
crowded, turn to rushing rivers. But all this is remote from Egypt.
After its confluence with the Atbara no drop of water reaches the Nile,
and it flows for seven hundred miles through the sands or rushes in
cataracts among the rocks of the Nubian desert. Nevertheless, in spite of
the tremendous diminution in volume caused by the dryness of the earth
and air and the heat of the sun--all of which drink greedily--the river
below Assuan is sufficiently great to supply nine millions of people with
as much water as their utmost science and energies can draw, and yet to
pour into the Mediterranean a low-water surplus current of 61,500 cubic
feet per second. Nor is its water its only gift. As the Nile rises its
complexion is changed. The clear blue river becomes thick and red, laden
with the magic mud that can raise cities from the desert sand and make
the wilderness a garden. The geographer may still in the arrogance of
science describe the Nile as 'a great, steady-flowing river, fed by the
rains of the tropics, controlled by the existence of a vast head reservoir