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Photograph from Alfred Pearce Dennis
THE LIFE-GIVER OF EGYPT BESTOWS ITS LARGESS OF WATER UPON DATE PALMS AND FLOCKS page 277). "Nature ordained that the Nile should overflow once a year and flood the agricultural plains of its valley, bestowing at once the twin gifts of moisture and fertility. When the flood has passed and the water has subsided, the farmer sows his seed and grows his annual crop" (see text,
Water is rushing in from the Nile, the level of which is raised to a point above that of the fields by the great Nile Barrage, thrown across the river north of Cairo. It is this remarkable engineering achievement that enables the Egyptians to employ a system of continuous irrigation throughout the Delta.
Successive waves of invaders have conquered the land of Egypt and held sway over its fertile valley, but while they have succeeded in changing the language and religion they have never changed the peasant life. These Nile farmers are threshing wheat with oxen and sledge in the same way to-day as in the days of Moses and before.
HARVESTING A ROOT CROP IN A LAND OF VEGETARIANS
The diet of the Egyptian farmer and laborer is almost exclusively vegetarian. The qulquas, here being harvested, is one of several root crops which, together with green corn, beans, and sweet potatoes, constitute the staple fare of the fellahin (see text, page 289).
A SACRIFICE ON THE ALTAR OF PROGRESS: THE TEMPLE OF ISIS, PHILA The building of the great Aswan Dam caused the Island of Phila to be submerged from December to April each year. Its beautiful temple ruins have been strengthened to resist the rush of the waters of the Nile flood, but the fine coloring has been largely destroyed by the annual submergence. Phile was an important shrine for the worship of the goddess Isis.
The ingenuity of man, however, has contrived by art to supplement the gifts of Nature. Nature ordained that the Nile should overflow once a year and flood the agricultural plains of its valley, bestowing at once the twin gifts of moisture and fertility. When the flood has passed and the water has subsided, the farmer sows his seed and grows his annual crop. Traditionally and historically, it is either a feast or a famine in Egypt. For a brief season the abounding flood, to be succeeded for the balance of the year by blazing suns and killing droughts.
THE ASWAN DAM IS THE KEYSTONE OF MODERN EGYPT
The ingenuity of man has harnessed the great river by holding back the flood of waters during the freshet season and doling out these husbanded supplies during the lean months of the year. Through this device, streams of living water can be carried every month of the year to the roots of growing plants.
The great stone dam at Aswan is in reality the keystone of modern Egypt. This huge rampart of masonry, which retains a 90-foot head of water, weighing 2,340,000 tons, is pierced at its foot by 180 sluice-gates. These gates, kept wide open when the annual flood is coming down, late in the summer, are gradually closed when the crest of the flood has passed. By January the reservoir is full and remains so during February and March.
When the supply of water begins to fail, in the late spring and early summer, sluices are opened and stored water added to the normal discharge.
Great barrages are thrown across the Nile farther downstream. These are masonry obstacles laid across the river's course to raise the water in the stream to the level of the irrigation canals. The Nile Barrage, a few miles below Cairo, is capable of raising the water level for the irrigation of the entire Delta by as much as 20 feet (see map, page 272).
Members of an Egyptian labor corps are employing the talents of a professional scribe.
Under the old system the water had to be mechanically raised by muscular effort from the natural level of the river. Now gravity faithfully discharges a task which it would require a million aching arms and backs to perform (see page 293).
Perennial irrigation, as has been explained, means an all-year supply of water to the Egyptian farmer. The huge volume of water required for irrigating the porous soils of the Delta under the blazing semitropical sun may be put at about 201 tons per acre per day as a minimum. Cotton-growing requires about 25 tons of water daily, while rice culture requires 60
THE MYSTERY OF THE NILE IS SOLVED
Man and his works in Egypt have existed only by grace of the river. There has always been something mysterious about the annual rise of the Nile. Such a seemingly slight thing as a reversal of the winds that sweep in summer across equatorial Africa from the Atlantic would cut off the annual flood and lay waste the richest agricultural valley in the world.
But while the annual floods have varied from time to time in volume they have. never in recorded history been entirely cut off. The apparition of the annual rise of the Nile is one of Nature's certitudes, as well established and as universally accepted as the rising and setting of the sun.
The ancient Egyptians were continually casting about for an explanation of the annual flood, but they never succeeded in penetrating to the heart of the mystery. There is no longer the slightest mystery about a subject that baffled the intelligence of the ancient world. The White and the Blue Nile, meeting at Khartum, form the great River Nile. The sources of the Nile are, therefore, dual-the one constant, the other variable.
The White Nile finds a catchment basin in a series of lakes, of which the greatest is Victoria, in equatorial Africa. This lake is some 2,500 miles by river from where the great stream debouches into the Mediterranean. The supply of water from the White Nile is fairly constant and is sufficient to furnish the River Nile with approximately the volume of water registered at mean low ebb.