The principal lakes of the Congo basin are Lake Bangweolo, or Bemba, one hundred and fifty miles long from east to west, and Lake Moero, having a length of sixty miles. There are several lakes of this basin still unvisited. They are said to be of vast extent and to lie two thousand feet above the level of the sea.
Lake Nyassa belongs to the Zambesi basin. It covers an area of nearly nine thousand miles in this great river basin. Lake Shirwa, on the plateau southeast of Lake Nyassa, is enclosed by mountains. It has an elevation of two thousand feet above the sea. Its water is brackish and has no outlet. Lake Tanganyika occupies an area of more than ten thousand square miles. A broad channel unites it with Lake Liemba, in the south. No outlet was for many years discovered for Tanganyika. It is probably a continental lake; for its waters are not perfectly fresh, and its drainage is very small.
Lake Tchad is the greatest lake of the continental system of North Africa. It consists of a shallow lagoon of very variable extent. Numerous islands dot its surface. Its waters are fresh and clear, and the overflow is carried off by the Bahr-el-Gazal to the northeast. Lake N'gami is in the southern continental system. It corresponds to Lake Tchad of the northern system. It is a shallow, reedy lagoon. Its extent varies according to the seasons. Its surplus water is carried by the Zuga River off to the eastward. Within the areas of continental drainage, salt lakes occur frequently. Assal Lake, in Abyssinia, is the most remarkable of these salt lakes.
CHAPTER XXVIII.
MOUNTAINS OF AFRICA.
No other portion of land on the surface of the globe is so difficult of access as Africa. This is owing to the mountainous character of large portions of its coast line.
"The contrast between the broken European shores and the massive African coasts of the Mediterranean was observed by the earliest geographers; the same continuous, unbroken margin extends along all the sixteen thousand miles of its shore line.
"Guarded by its inhospitable shores, large areas of the interior of the continent are as yet altogether unknown. As a whole, the continent may be regarded as a vast plateau, bordered round by maritime ranges, which form the seaward edges of the interior table-lands."
The ranges of the eastern coast have been so little explored that much has yet to be learned of their character. They extend from the highlands of Abyssinia to the extreme southern point of the continent. The so-called Mountains of the Moon belong to this system. The early explorers erred when they supposed that they stretched across Central Africa from east to west. So great has been the diversity of opinion, that some authors deny the existence of these mountains.