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TANGANYIKA (a name said by V. L. See also: East-Central See also: Africa, the longest See also: freshwater lake in the See also: world, measuring just over 400 m., with a general breadth varying from 30 to 45 m., and an See also: area of about 12,700 sq. m
.
It lies at an altitude of about 2600 ft. above the See also: sea, and occupies the See also: southern end of the See also: great central rift-valley, which terminates suddenly at its southern point, the See also: line of depression being represented farther See also: south by the more easterly trough of Lakes See also: Nyasa and Rukwa, from which Tanganyika is separated by the Fipa See also: plateau, composed of old granitoid rocks; though even here traces of old valley-walls are said by Dr Kohlschiitter to exist
.
See also: North of Tanganyika the valley is suddenly interrupted by a line of See also: ancient eruptive ridges, which See also: dam back the See also: waters of Lake See also: Kivu (q.v.), but have been recently cut through by the outlet of that lake, the Rusizi, which enters Tanganyika by several mouths at its See also: northern end
.
The flat plain traversed by the See also: lower Rusizi was evidently once a portion of the lake floor
.
Tanganyika has been formed by the subsidence of a long narrow See also: tract of country relatively to the surrounding plateaus, which fall to the lake in abrupt cliffs, some thousands of feet high in places
.
The See also: geological formations thus exposed show that the plateaus are composed of a See also: base of eruptive material, overlaid by enormous deposits of reddish sandstones, conglomerates and quartzites, exposed in parts to a See also: depth of 2000 feet
.
Besides the plain to the north, a considerable area to the west, near the Lukuga outlet (see below), shows signs of having been once covered by the lake, and it is the opinion of Mr J
.
E
.
S
.
See also: Moore that the See also: sandstone ridges which here bound the trough have been recently elevated, and have been cut through by the Lukuga during the See also: process
.
The past See also: history of the lake has long been a disputed question, and Mr Moore's view that it represents an old See also: Jurassic arm of the sea is contested by other writers
.
This idea originated in the See also: discovery of a jelly-See also: fish, gasteropods, and other organisms of a more or less marine type, and presenting some See also: affinity with forms of Jurassic age
.
This See also: fauna, to which the See also: term " halolimnic " has been applied, was known to exist from specimens obtained by Mr E
.
C
.
Hore and other early travellers, but has been more systematically studied by Mr Moore (during expeditions of 1896 and 1898—99) and Dr W
.
A
.
Cunnington (1904—5)
.
Various considerations throw doubt on Mr Moore's theory, especially the almost entire See also: absence of marine fossiliferous beds in the whole of See also: equatorial Africa at a distance from the sea, of any remains of Jurassic faunas which might See also: link the Tanganyika forms with those of undoubted Jurassic age in neighbouring regions
.
The formation of the existing rift-valley seems in any See also: case to date from See also: Tertiary times only
.
Although drinkable, the See also: water of the lake seems at times at least to be very slightly brackish, and it was supposed by some that no outlet existed until, in 1874, See also: Lieutenant See also: Cameron showed that the surplus water was discharged towards the upper See also: Congo by the Lukuga See also: river, about the See also: middle of the west See also: coast
.
The outlet was further examined in 1876 by Mr (afterwards See also: Sir See also: Henry)
See also: Stanley, who found that a See also: bar had formed across the outlet, and it has since been proved that the outflow is intermittent, ceasing almost entirely after a See also: period of scanty rainfall, and becoming again established when the lake-level has been raised by a series. of See also: rainy years
.
About 188o it was See also: running strongly, but about this See also: time a gradual fall in the lake-level set in, and was continued, with occasional pauses, for some twenty years, the amount being estimated by Wissmann at 2 feet annually
.
In 1896 Captain H
.
See also: Ramsay found that a wide level plain, which had before been covered by water, intervened between See also: Ujiji and the lake, but stated that no further sinking had taken place during the two previous years
.
Near Tembwe See also: Head Mr I,
.
A
.
See also: Wallace found See also: recent beaches 16 feet above the existing level
.
The Lukuga was reported blocked by a bar about 1897, but a certain amount of water was found flowing down by Mr Moore in 1899; while in 1901 Mr Codrington found the level 4 or 5 feet higher than in 1900, the outlet having again silted up
.
A continued rise was also reported in 1907
.
In any case, the alterations in level appear
to be merely periodic, and due to fluctuations in rainfall, and do not point, as some have supposed, to a secular drying up of the lake
.
The lake is fed by a number of See also: rivers and small streams which descend from the surrounding See also: highlands
.
The Mlagarazi (or Malagarasi), perhaps the largest feeder, derives most of its water from the rainy districts east of the See also: strip of high ground which shuts in the lake on the north-east
.
The See also: main stream, in fact, has a nearly circular course, rising in 4° 40' S., only some to See also: miles from the lake See also: shore and less than 40 miles from its mouth, though its length is at least 220 miles
.
The other branches of the Mlagarazi, which See also: traverse the somewhat arid granite plateaus between the lake and 33° E., bring comparatively little water to the main stream
.
In its lower course the river is a rapid stream flowing between steep See also: jungle-clad hills, with one fall of 50 feet, and is of little use for navigation
.
The various channels of its See also: delta are also obstructed with See also: sand-See also: banks in the dry season
.
The Rusizi, the next (or perhaps equal) in importance among the feeders of the lake, has already been spoken of . It receives many tributaries from the sides of the rift-valley, and is navigable for canoes . The remaining feeders are of distinctly less importance, the Lofu, which enters in the south-west, being probably the largest . Tanganyika has never been sounded systematically, but the whole configuration of its valley points to its being generally deep, and this has been confirmed by a few actual measurements . Dr See also: Livingstone obtained a depth of 326 fathoms opposite See also: Mount Kabogo, south of Ujiji
.
Mr Hore often failed to find bottom with a line of 168 fathoms
.
The French explorer, Victor See also: Giraud, re-ported 647 metres (about 350 fathoms) off Mrumbi on the west coast, and Moore depths of 200 fathoms and upwards near the south end
.
The shores fall rapidly as a See also: rule, and there is a marked scarcity of islands, none occurring of any See also: size or at a distance from the coast line
.
The lake is subject to occasional storms, especially from the south-south-east and south-west, which leave a heavy swell and impede navigation
.
The cloud and See also: thunder and See also: lightning effects are spoken of as very impressive, and the scenery of the lake and its shores has been much extolled by travellers
.
Vegetation is generally luxuriant, and See also: forest clothes portions of the See also: mountain slopes
.
The lake lies on the dividing line between the floral regions of East and West Africa, and the oil-palm characteristic of the latter is found on its shores
.
The largest See also: timber See also: tree is the mvule, which attains vast dimensions, its trunk supplying the natives with the dug-out canoes with which they navigate the lake
.
The more level parts of the shores have a fertile See also: soil and produce a variety of crops, including See also: rice, See also: maize, manioc, sweet potatoes, See also: sugar-See also: cane, &c., &c
.
The waters display an abundance of animal See also: life, crocodiles and hippopotami occurring in the hays and river mouths, which are also the haunts of water-See also: fowl of many kinds
.
Fish are also plentiful
.
Various sections of the See also: Bantu division of the See also: Negro See also: race dwell around the lake, those on the west and south-west showing the most pronounced Negro type, while the tribes on the east exhibit some intermixture with representatives of the Hamitic stock, and (towards the south) some traces of Zulu influence
.
The surrounding region has been overrun by See also: Arabs and Swahili from the East See also: African coast
.
Though rumours of the existence of the lake had previously reached the east coast, Tanganyika was not visited by any See also: European until, in 1858, the famous expedition of See also: Burton and Speke reached the Arab See also: settlement of Ujiji and partially explored the northern portion
.
Ujiji became famous some years later as the spot where Dr Livingstone was found by Stanley in 1871, after being lost to sight for some time in the centre of the continent
.
The southern See also: half of the lake was first circumnavigated by Lieutenant V
.
L
.
Cameron in 1874, and the whole lake by Stanley in 1876
.
The mapping of Tanganyika, which long rested on the surveys of Mr E
.
C . Hore, published in 1882, received considerable modification, about 1899-1900, from the See also: work of Fergusson, Lemaire, Kohlschutter and others, who showed that while the general outline of the coasts had been See also: drawn fairly correctly, the whole central portion, and to a lesser degree the northern, must be shifted a considerable distance to the west
.
At Mtowa, in 5° 43' S., the amount of shifting of the west coast was about 30 miles
.
At Ujiji, on the east coast, the longitude was given by Kohlschutter as 290 40' 2" E. as compared with 30° 4' 30" E. of Cameron, a difference of some 25 miles
.
In the See also: partition of Africa among the European See also: Powers, the shores of Tanganyika have been shared by Belgium, Great Britain and See also: Germany, Great Britain holding the southern extremity, Germany the east, and Belgium the west
.
Stations have been established on the lake by all three Powers, the See also: principal being—German: Bismarckburg in the south and Ujiji in the north; See also: British: Sumbu and Kasakalawe, on
Cameron See also: Bay; Belgian: Mtowa or Albertville in 6° S
.
Missionaries, especially the Catholic " See also: White Fathers," are also active on its shores
.
A small steamer, the "
See also: Good See also: News," was placed on the lake by the See also: London Missionary Society in 1884, but afterwards became the See also: property of the African Lakes Corporation; a larger steamer, the " Hedwig von Wissmann," carrying a See also: quick-firing See also: Krupp See also: gun, was launched in 190o by a See also: German expedition under Lieutenant Schloifer; and others are owned by the " Tanganyika Concessions " and See also: Katanga companies
.
The greater See also: part of the See also: trade with Tanganyika is done by the African Lakes Corporation by the See also: Shire-Nyasa route, but the Germans have opened up overland routes from See also: Dar-es-See also: Salaam
.
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