Page:The New International Encyclopædia 1st ed. v. 14.djvu/664

* NILE. 566 NILE. the whole becomes compressed into a dense and Kolid mass, which covers the river surface from bank to bank, and underneath which the stream rushes as through a sluice gate. These blocks at times attain a thickness of 15 feet below the water and 4 or 5 feet above it. The surface in places is so solid that lii|)p(ipotami- and even elephants can cross it without danger. Naviga- tion of the river is thus rendered impossible. In 18!)U-li>00, after the recoiupicst of the Sudan, the Government attempte<l with much success to open navigation in the main channel by cutting down into the sudd, tearing the sections away by steamboats, and setting the masses thus sej)a- rated afloat. This region is very unhealthful and the inhabitants are few. It is believed that the swamp and sudd region embraces an area of about 12.000 scuuue miles. All the streams are reunited 02 miles below Lake Xo and receive on the right bank the Sobat Kiver, coming from the southern extension of the Abyssinian highlands, a navigable river for 212 miles from its mouth. Below the Sobat, the White Xile takes a definite northern course and Hows, a mighty, though slug- gish stream, to Khartum, where the White and the Blue Niles mingle their waters. The i51ue Nile is a very different river. It rises in the Alpine heights of Abyssinia, descends to the White Nile between its high banks with a very rapid ciirent, and in the flood time it is reddened by the (piantitiis of alluvia with which it is surcharged. The White Nile gives to Eg^'pt the larger i|uaiitity of water: the Blue .Nile spreads over the liclds the fertile sediment that enriehes them. Thus each had its distinctive function in creating Kgvpt out of the desert sands. Khartum, at the junction of these rivers, is at the heart of the great hydrogiaphic system, and is naturally the metropolis of the Eastern Sudan. The Blue Xile, from its great reservoir. Lake Tsana, 5840 feet above the sea, has a wind- ing course of S'.i'.) miles down the ]ilateau and over the jihiin to Khartum. Jluch land in its valley is suitable for agricultural development. The river needs seientilic regulation so that it may best serve the interests of Eg>-pt. Under the agreement with King Menelek of Abyssinia (1902) for the delimitati<m of the boundary be- tween his country and the Sudan, the Egv-ptian Government has authority to regulate the flow of water in the u])iier river. The Cape to Cairo Railroad will ftdhiw the Blue Nile for a consid- erable distance above Khartum, to avoid the swamp region of the White Nile. From a little below Khartum to the Mi^diter- ranean the river flows tlircmgh one of the most arid deserts in the world, without receiving a single tributary excepting the Atbara. ISO miles below Khartum, which drains the northern high- lands of .byssinia. but is nearly dry in sununer. Throughiiut this long course, the valley of the Nile is jnerely a cleft in the desert plateau, the alluvial plain along the river being hounded by barren elifl's. which here and there rise to 1000 feet. The volume of the river is greatly depletid by evaporation in this part of its course. The second section of the rivi^r, the ^liddle Nile, ex- tends from Khartum to .^ssuan. a distance of 1124 miles. It is a region- of cataracts, there be- ing .'iol miles of rapicis, with a total fall of fi.'iO feet, and 77:! miles of navisation, with a fall of 312 fi<.l I'Ih' cataracts, in their order as the river is descended, may be briefly described: The Sixth Cataract, beginning 52 miles below Kliartum, is a little over one mile long, and the drop in the river is 20 feet. The Fifth Cataract begins 28 miles north of Berber, is 100 miles long, has three principal rapids, and the descent is over 200 feet. Abu Ilamed is a little below the foot of this cataract. The Fourth Cataract is between Abu Hamed and Dongola. and drops ItiO feet in ti8 miles. The very fertile region of Uongola is between the Fourth and the Third cataracts. The Third Cataract, with two rapids, is 45 miles long and the fall in the river bed is 30 feet. The Second Cataract is ~'3 miles farther down the river, is 124 miles long, with four rajiids. and it falls 210 feet. The town of Wadi- Halfa lies at its foot. The First Cataract is 214 miles farther down the Nile, is three miles long, droi)s 10 feet, aud Assuan lies at its foot. The fact that below Assuan lies the great region of irrigation, fertility, and dense population, and that this portiim of the Nile is hemmed in by high hills, marked Assuan as the best place to build a great dam across the river to keep back at flood time much of the water which hitherto had gone to waste, so that it might be utilized in the dry season and give Egypt iierennial irriga- tion. The third section of the river is the Lower Nile, extending from Assuan to the head of the Delta, an open waterway.' navigable by large vessels, with Cairo near its foot. The current is slow during the low river in summer — less than two feet a second. The velocity in flood is from .314 to GI2 feet per second. Along the lower ])art of this section a divergent channel knowni as the Bahr-Yusuf (.Joseph's Canal) extends paral- lel to the Nile on the west side, finally discharg- ing its waters in the depressed area of the Faymn (q.v.). The fourth section of the river is the Delta or 'Garden of Egypt.' It is pierced in all directions by irrigation canals and navigable channels. Wlien the Xile is in flood, its tendency is to increase the height of its banks by deposits of loam and sand. These banks are artificially strengthened and the river thus kept to a definite course. The river reaches the sea through the Rosetta and Damietta motiths, and the canals that cover the Delta like a network carry their surplus waters into a chain of salt lakes that ex- tends iM'hind the sandy shore. As a drainage out- let, a navigalile highway, and a source of power the Xile is surpassed by many other rivers. Its imicpie distinction is that it has turned Egjpt from a desert into one of the richest agricultural lands, supporting a population of about 000 to the square mile. There are periods of exceptional flood and low water; but tlu' extraordinary regu- larity with which, as a rule, (he river rises and falls contributes to the sccurily of farming. The heavy rains in the basin of the White Xile during April ilrive the waters of that marshy region ilown upon Egypt, where they appear nt Cairo about .June 15th. A fortnight later the real Hood begins, for the May rains in .Miy^sinia fill (he Blue Xile with the richest muddy water. The rise is sometimes as rapid as three feet a day, the flood being heightened by the large vol- ume brought down by the .Mbara. The maxi- mum flood reaches .ssuan about Septendier 1st, and it woild be at Cairo a few days later were it nfit that the water is diverted to the land and the whole Xile 'alley is a great lake. For tbi»