current. This stream, which is known to the Dinkas as the Atem, follows a course generally parallel to the Jebel, being bounded eastward by forest land. Opposite Kanisa (6° 46′ N.), on the main river, the Atem divides into two channels, marshy land extending at this point a great distance to the east. The western branch, or Awai, rejoins the Jebel near Shambé 7° 6′ N. The eastern branch or Myding continues through the marshes, eventually joining the Bahr-el-Zeraf (see below) in its lower course.
Except for the Atem divergence the Nile, despite the swamps through which it passes, maintains a fairly definite course, with a considerable depth of water as far as Shambé, where, to the west, is a large lagoon. Five miles lower down the river splits into two great channels. That to the left, the main stream, continues to be known as Bahr-el-Jebel, but is sometimes called by its Dinka name Kir. The right branch, or Bahr-el-Zeraf (Giraffe river), has a more easterly direction, and does not rejoin the main river until 50 m. below its confluence with the Bahr-el-Ghazal (q.v.). From the point of bifurcation the Bahr-el-Jebel flows for 230 m. in a general northwesterly direction until it is joined by the Bahr-el-Ghazal coming from the south-west. The whole region is a vast expanse of low land crossed by secondary channels, and flooded for many miles in the rainy season. At the junction of the Bahr-el-Ghazal and the Bahr-el-Jebel in 9° 29′ N. the permanently submerged area is usually named Lake No, but the Arabs call it Moghren-el-Bohur (meeting of the rivers). Lake No in the rains covers about 50 sq. m. In the Bahr-el-Jebel occur the great accumulations of “sudd” (q.v.), masses of floating vegetation which obstruct and, if not removed, prevent navigation. The aspect of the river throughout the sudd region is monotonous and depressing. On all sides stretch reaches of the reed known as um suf or mother of wool (Vossia procera), ambach, Bus and papyrus. These grasses rise 15 to 20 ft. above the water, so as often to close the view like a thick hedge. The level of the flat expanse is broken only at intervals by mounds of earth, erected by the white ants and covered with a clump of brushwood or trees; the moisture in the air is excessive; mosquitoes and other swamp flies swarm in myriads. And yet touches of beauty are not wanting. Water lilies (Nymphaea stellata and Nymphaea Lotus)—white, blue and crimson—often adorn the surface of the stream. Occasionally the rare and odd-looking whale-headed stork or Balaeniceps rex is met with among the reeds, and at night the scene is lit up by innumerable fire-fiies.
The White Nile.—From the confluence with the Bahr-el-Ghazal at Lake No, the main stream, which here takes the name of Bahr-el-Abiad, or White river, adopts the easterly course of the tributary stream. Forty miles below the point where the Bahr-el-Zeraf reunites with the main branch, the Nile receives its first great eastern affluent—the Sobat (q.v.), whose head-streams rise in the mountains of south-west Abyssinia and the region north of Lake Rudolf. Just above the Sobat junction the Nile resumes its northern course. It passes through a great alluvial plain, stretching from the spurs of the Abyssinian highlands in the east, to the hilly districts of Kordofan in the west, and covered with high grass and scattered bush. The swamps still bound it on either bank, but the river again flows in a well-marked channel with defined banks. About 56 m. below the Sobat mouth, in 9° 55′ N., lies (on the left bank) Fashoda (renamed in 1904 Kodok), an Egyptian town founded in 1867 on the site of Denab, the old “capital” of the Shilluks, and famous for the crisis between England and France in 1898 through its occupation by the French officer Marchand. For the next 270 m. the scenery is very monotonous. The river flows in a wide channel between broad swamps bordered by a belt of forest on either bank. At Abu Zeid (about 13° 5′ N.) for a distance of nearly 4 m. the river is extremely broad and shallow, being fordable at low water. Fifteen miles lower down, at Goz Abu Goma—which is the northern limit of the sudd vegetation—the river is divided into two channels by Abba Island, wooded, narrow and 28 m. long. On Abba Island lived, for some years before 1881, Mahommed Ahmed, the Mahdi.
The Blue Nile.—Five hundred and twenty miles below the Sobat mouth and 1652 m. from Ripon Falls, in 15° 37′ N., the White Nile is joined by its greatest eastern confluent the Bahr-el-Azrak or Blue Nile. In the fork of the two rivers stands Khartum,[1] the capital of the Anglo-Egyptian Sudan, whilst on the western bank of the White Nile is Omdurman, the former Mahdist capital. The Blue Nile, or Abai as it is called in Abyssinia, rises in the Gojam highlands in 11° N. and 37° E., and flowing northwards 70 m. enters Lake Tsana (q.v.) near its south-west corner, to issue again at the south-east end. The Abai and its tributaries drain a great part of the Abyssinian plateau. The complicated river system is best understood by a study of the map. The Abai itself on leaving Lake Tsana makes a great semicircular sweep S.E. to N.W., from the highlands of Ethiopia to the plains of Sennar. In this section of its course its swirling waters rush over a long series of cataracts and rapids, descending from a height of 5770 ft. at the outlet to about 1400 ft. at Fazokl or Famaka (11° 17′ N., 35° 10′ E.), where it crosses the Abyssinian frontier, and flows through the plains of Sennar to its confluence with the White Nile at Khartum, 1300 ft. above sea-level. Of the tributaries of the Abai the majority join it on its left bank. The Bashilo, Jamma and Muger, which reach the Abai in the order named, drain the country east of the main stream between the basins of the Takazze and the Hawash. The Guder, with a south to north course, rises in the mountains which form the watershed between the Nile and the Lake Rudolf basin. Next comes the Didessa, a large stream rising near the head-waters of the Baro (the main upper branch of the Sobat) and flowing N.W. to the Abai, the confluence being in about 10° N., 35° 40′ E. It has an early rise and a long flood period, being by far the most important tributary of the Blue Nile. The Dabus or Yabus rises about 9° N., 34° 30′ E., and flowing north joins the Abai near the spot where that river breaks through the Abyssinian hills. All these affluents are perennial, as is the Bolassa or Yesien, a right-hand tributary which reaches the Abai below the Yabus. Four miles below Famaka the river is joined on its left bank by the auriferous Tumat, an intermittent stream. In Sennar it receives on its right bank two considerable tributaries from the Abyssinian heights, the Dinder, a very long but not perennial stream, and the Rahad, waterless in the dry season, copious and richly charged with sediment during the rains from June to September. At this period the discharge of the Blue Nile rises from less than 200 to over 10,000 cub. metres per second, thus greatly exceeding that of the White Nile itself, which is only about 800 cub. metres during the floods above the confluence. The length of the Blue Nile is about 850 m. The country, El Gezira, enclosed in the triangle formed by the junction of the White and Blue Niles forms the most fertile portion of the Sudan. It only requires irrigation to render it one of the finest grain-producing areas in the world.
The Atbara.—Two hundred miles below Khartum—at Ed-Damer—the Nile is joined by the last of its tributary streams—the Atbara or Bahr-el-Aswad (Black river). The Atbara, some 800 m. long, rises in the tableland north of Lake Tsana, being formed by the junction of the Angreb, Salaam, Aradeb, Goang and other mountain streams. Making its way towards the Nubian plains, the river flows in a north-westerly direction, joining, in 14° 10′ N., 36° E., the Bahr Setit or Takazze (see Abyssinia), a river coming from the east and having a volume of water as large as, if not larger than, the Atbara. The united stream preserves, however, the name of Atbara, and at its confluence with the Nile has a breadth in flood time of over 600 yds. The Atbara and its tributaries, like many of those which feed the Blue Nile, rapidly dwindle after the rains into the smallest limits. In its lower course the Atbara runs completely dry, but higher up water may be found in deep pools, hollowed out of the sand bed of the stream by the river when in flood. These pools are full of fish, turtles, crocodiles and hippopotami, which remain imprisoned until the return of the flood. The country comprised between the Nile proper, the Atbara and the Blue Nile is identified with the island of Meroë of ancient history.
The Cataracts.—Downstream of the Atbara junction the Nile continues its course to the Mediterranean, traversing a distance of over 1600 m. without receiving a single tributary on either bank. Below Khartum the river makes a great S-shaped bend, and leaving behind the cultivable land pierces the Nubian desert. In its progress the volume of water suffers continual diminution from evaporation, owing to the extreme dryness of the air. The valley of the river is here very narrow, and the desert land in places comes right to the water’s edge. Elsewhere high and barren cliffs shut in the valley. Between Khartum and Wadi Halfa (the northern end of the great bend), a distance of over 900 m., occurs a series of cataracts, known as the 2nd, 3rd, 4th, 5th and 6th (the 1st cataract is lower down the river at Assuan). That first met with on descending the river from Khartum is the 6th (or Shabluka) cataract. The river here (53 m. below Khartum) is narrow and picturesque. The rapid is 11 m. in length, in which distance the Nile falls some 20 ft.[2] After 188 m. of smooth water the 5th cataract is reached. It begins 28 m. below Berber (a town on the right bank at the head of a caravan route to the Red Sea), and with three principal rapids extends for 100 m.—the drop in this distance being rather more than 200 ft. At the foot of this cataract is the town of Abu Hamed, at the eastern end of the middle of the S bend. The 4th cataract begins 60 m. down stream from Abu Hamed. It is 69 m. long and has a drop of 160 ft. Between the 4th and 3rd cataracts there is a stretch of 194 m. on a very gentle slope (112000). This reach constitutes the province of Dongola, and here the cultivable land on the western side of the river is of greater extent than usual in the desert zone. The 3rd cataract, 45 m. long, has a drop of some 36 ft. After another smooth reach extending 73 m. the 2nd cataract, which ends just above Wadi Halfa, the northern frontier town of the Anglo-Egyptian Sudan, is reached. This cataract is 124 m. long and has a fall of 216 ft. Between the 2nd cataract and Assuan are 214 m. of smooth water with a scarcely perceptible slope, 112500. The average breadth of the river here is 1640 ft. It runs through a sandstone bed, and the current is guided in many places by spurs of masonry built by the ancient Egyptians.
Lower River and Delta.—For some distance above Assuan the river is studded with islands, including those of Philae and Elephantine. The rapids south of the town used to form the 1st cataract, where
