Sources of the Nile.—The question of the sources of the Nile opens up a time-honoured controversy (see under Story of Dis covery p. 455). Victoria Nyanza (q.v.) is the great reservoir whence issues the Nile on its long journey to the Mediterranean. But if the source of the river be considered to be the most remote headstream (measured by the windings of the stream), the dis tinction belongs to one of the upper branches of the Kagera. Among the feeders of Victoria Nyanza the Kagera is the most important, both for length of course and volume of water carried, draining the region of greatest rainfall round Lake Victoria.
Three chief branches unite to form the Kagera, and of these the most important for the volume of water carried is said to be the Nyavarongo. (i.) The Nyavarongo is formed by the union of various mountain streams, the Rukarara and the Mhogo being the chief. The Rukarara rises in about 2° 20' S., 29° 20' E., at an elevation of some 7,000 ft., in a picturesque and bracing region immediately east of the Albertine Rift valley. The Nyavarongo first flows north to about I° 40' S., then turning in a sharp bend east and south, and on again reaching 2° 20' S., unites with the Akanyaru just west of 30° E. (ii.) The Akanyaru, which comes from the south-west, has been sometimes considered the larger stream, but according to Dr. Richard Kandt it carries decidedly less water, while its course is shorter than that of the Nyavarongo. The combined stream takes an easterly and southerly direction, flowing in a swamp valley and joining a little west of 31° E. the third branch of the Kagera, the Ruvuvu, coming from the south.
(iii.) The source of the Ruvuvu is in about 55' S., 291° E., but its most southern tributary, and the most distant stream sending its waters towards the Nile, is the Lavironza. The Lavironza rises in about 45' S., 50' E., and flows north-east, joining the Ruvuvu, which has hitherto had an easterly direction, in about 3o° 25' E., 3° 1o' S. From this point the Ruvuvu flows east and north to its junction with the Nyavarongo.
From this confluence the combined stream of the Kagera flows north and north-west in a level valley strewn with small lakes until almost I° S., when it turns east, and finally empties itself into Victoria Nyanza just north of I° S., the mouth forming a small projecting delta. Its lower course is navigable by shallow draught steamers. The total length of the Kagera, reckoning from the source of the Nyavarongo, is some 43o miles. The average volume discharged is estimated, from measurements which have been made to be about 35o cu. metres per second. All the other feeders of Victoria Nyanza are small and often intermittent rivers, the largest being probably the Nzoia,which enters on the north-east from the plateaus south of Mount Elgon.
yds. across, and divided into three channels by two small wooded islands, are named the Ripon Falls, after Earl de Grey and Ripon (afterwards 1st marquess of Ripon), president of the Royal Geo graphical Society in 1859.
The Victoria or Somerset Nile, as this section is called, has at first the character of a mountain stream, racing swiftly through a rocky channel often walled in by cliffs (at times 18o f t. high) and broken by picturesque islands and countless rapids. It receives the waters of several streams, which, rising within a few miles of the Victoria Nyanza, flow north. For 133 m. its course is north north-west, when, on being joined by the river Kafu (on which Fort Mruli stands), about I° 39' N., 32° 20' E., it takes the north east direction of that channel, and it is not till 2° N. that the river again turns westward towards Lake Albert. Seventy miles below the Ripon Falls the Nile enters a marshy lake of irregular outline, running mainly east and west, and known as Kioga (or Choga). The current of the Nile is clearly discernible along the western shore of this lake, which is 3,514 ft. above the sea. East wards the lake breaks into several long arms, which receive the waters of other lakes lying on the plain west of Mount Elgon. One of these, named Lake Salisbury, lies in I° 4o' N. and 34° E.; east of this lake and connected with it is Lake Gedge. Lake Kioga also receives the Mpologoma, a river which rises in the foothills of Elgon and flows east and north, attaining a width of II- m.; and from the south (west of the Nile) a broad lacustrine river, the Seziwa. The Kioga lake system, lying north of the ridge which separates it from Lake Victoria, owes its formation in part to the waters pouring down from the Nyanza, and is in the nature of a huge Nile backwater. The lake itself is rarely more than 20 ft. deep; its greatest length is 85 m.; its greatest width 10 m. Below Mruli, the fall in the bed levels of the Nile, which up to this point has been comparatively gradual, increases considerably. At Karuma, where the western bend to Lake Albert is made, the river falls over a wall-like ledge of rock, 5 ft. high, which extends across its bed. But the great feature of the Victoria Nile is the Murchison Falls (named by Sir Samuel Baker, their discoverer, after Sir Roderick Murchison, the geologist), situated in 2° 18' N. and 31° so' E. At this point the river rages furiously through a rock-bound pass, and, plunging through a cleft less than 18 ft. wide, leaps about 13o ft. into a spray-covered abyss. Downstream from these falls the river flows for some 14 m. between steep forest-covered hills, a wide and noble stream with a current so slow and steady that, at certain seasons, it is only from the scarcely perceptible drifting of the green water-plants called Pistia stratiotes that it can be observed. About 24 m. below the Murchi son Falls and 254 m. from Lake Victoria the river enters, through a wide delta, and across a formidable bar, the north-east end of Lake Albert. In its passage from the one lake to the other the Nile falls altogether about 1,400 f t. Taking its name from a fort which once existed there, the delta district is known as Magungo.