sheets of water, and for weeks and months together interrupting all communications. Lake Tuburi is the centre of a series of lagoons presenting a continuous waterway between the Upper Benue and the Tsad, while during the rains all the branches of the Shari delta, on the south side, are merged in a common stream 30 miles wide. When this great body of water reaches the lake it begins to rise rapidly, attaining its highest level towards the end of November.
The Shari, which in the local idioms has the same meaning as Tsad, is one of the great rivers of Africa, the problem of whose source, however, is not yet completely solved. At the same time, Schweinfurth's suggestion that the Welle of the Monbottu and Niam-Niam regions is its upper course, is now rejected by most geographers, who regard the Welle as an affluent of the Congo. The farthest eastern headstreams of the Shari are probably still over 600 miles from
the source of the Welle, taking their rise in the southern uplands of Dar-For and Wadai. According to the natives, the ramifications of its delta begin 360 miles above its mouth, at a point where it divides into two ba or chief branches, the Ba Bai, or Logon, flowing to the left, the Ba Busso, or Shari proper, to the right. But however this be, the eastern arm after receiving the Bahr-el-Abiad ("White River"), from the Banda territory, throws off a branch, the Ba Batchikam, which is again united 150 miles lower down. Farther on both main branches are merged in one, while a number of secondary channels find their way in shifting beds to the lake.
The annual discharge of the Shari is roughly estimated by Nachtigal at over 2,100 billion cubic feet, or an average of 70,000 per second, this quantity being at. least double the supply received by the lake from all other influents and the
