142 THE LAKE REGIONS OF CENTRAL AFRICA. 



not the Tanganyika, situated, like the Dead Sea, as a 

 reservoir for. supplying with humidity the winds which 

 have parted with their moisture in the barren and arid 

 regions of the south, maintain its general level by the 

 exact balance of supply and evaporation ? And may 

 not the saline particles deposited in its waters be wanting 

 in some constituent which renders them evident to the 

 taste ? One point concerning the versant has been 

 proved by these pages, namely, that the Tanganyika 

 cannot be drained eastward by rents in a subtending 

 mountain ridge, as was supposed by Dr. Livingstone 

 from an indiscriminately applied analogy with the 

 ancient head-basin of the Zambezi. Dr. Livingstone 

 (chap. xxiv. xxvi. et passim) informs his readers, from 

 report of the Arabs, that the Tanganyika is a large 

 shallow body of water ; in fact, the residuum of a mass 

 anciently much more extensive. This, however, is not 

 and cannot be the case. In theorising upon the eastern 

 versant and drainage of the Tanganyika, Dr. Livingstone 

 seems to have been misled by having observed that the 

 vast inland sea of geological ages, of which Lake Ngami 

 and its neighbour Kumadau are now the principal 

 remains, had been desiccated by cracks and fissures, 

 caused in the subtending soils by earthquakes and 

 sudden upheavals, which thus opened for the waters an 

 exit into the Indian Ocean. This may have happened 

 to the Nyassa, or Southern Lake ; it must not, however, 

 be generalized and extended to the Nyanza and the 

 Tanganyika. 



As in Zanzibar, there is little variety of temperature 

 upon the Tanganyika. The violent easterly gales, 

 which, pouring down from the cold heights of Usagara, 

 acquire impetus sufficient to carry the current over 

 Ugogo, Unyamwezi, and Uvinza, are here less distinctly 



