NILE, called by the Egyptians Hapi Mu, and by the Hebrews Sihor, the river of N. E. Africa, formed by the union of the Bahr-el-Abiad and the Bahr-el-Azrek. Captains Speke and Grant discovered that the first of these, the true Nile, flowed out of the Lake Victoria Nyanza. The second, the Blue Nile, has its source in Abyssinia. The White Nile, from its outfall from the Victoria Nyanza at the Ripon Falls, lat. 0° 20' N., long. 33° 30' E., flows N. W. and W. for about 230 miles, till it enters the Lake Albert Nyanza, within 30 miles of its N. ex tremity, whence the river again emerges. On issuing from the Victoria Nyanza the Nile rushes down due N. like a moun tain torrent, running off at last into long flats and expanding so as to form what is called Lake Ibrahim Pasha. In this part of its course the river is navigable, and continues to be so till it reaches the Karuma Falls. From these falls to the Murchison Falls (120 feet in height), near the Albert Nyanza, the river forms a series of rapids. Between the two Nyanzas the Nile is known as the Vic toria Nile or Somerset river. From Assuan to the sea the average fall of the Nile is two inches to a mile, and its mean velocity about 3 miles an hour. It waters and fertilizes the whole length of the land of Egypt. The delta of the Nile extends from lat. 30° 10' N. to 31° 30' N., and has a base on the Mediterranean of about 160 miles. In it the Nile spreads out into numerous streams, the two principal being those of Rosetta and Damietta. The total length of the Nile,
from its exit from the lake to the sea, is about 3,766 miles, measured along its course, or 2,200 miles in direct distance.
A great feature peculiar to the great river of Egypt is that from its junction with the Atbara to its mouth, a distance of upward of 1,600 miles, it receives no affluent whatever. With the ancient Egyptians the river was held sacred; the god Nilus was one of the lesser divinities. Its annual overflow is one of the greatest marvels in the physical geography of the globe, for it has risen to within a few hours of the same time, and to within a few inches of the same height, year after year, for unknown ages. The question of the source of the Nile is at once the oldest and the most recent of geography. By reference to the map of Africa the latest results of modern research will be seen.
The greatest dam (or barrage, as it is called) in the world is near Assuan, at the first cataract of the Nile, and a second one at Assiout. In this region there is no rainfall and the people depend entirely on irrigation to water their crops, and as they have only one river all water must come from the Nile. The Assuan dam blocks the river and holds in reserve, in a vast reservoir, the sur plus water which in the summer can be distributed over the fields, and make pro ductive all the year round hundreds of square miles of otherwise barren land. See DAM; EGYPT.