230 
EASTERN ETHIOPIA 
XVIII 
The southern extremity of the western arm was 
investigated by Burton and Speke, who discovered Lake 
Tanganyika (1858), and Lake Nyasa by Livingstone 
(1859). The western lake-chain has lieen carefully 
investigated by Moore and especially Lake Tanganyika 
(1896 and 1899). 
Lohelia WoUa-s1o)d. 
Lobelia ground on Mount Ruwenzori. (From a pliotograpli by 
Dr. A. F. R. Wollaston, Journal of the Linnean Society, 
1908, xxxviii, PI. xvii, Fig. 7.) 
Lake Tanganyika is the longest lake in the world ; it 
measures 420 miles in length, its breadth varies from 30 
to 50 miles. In some parts it is very deep. This 
enormous rocky cistern is formed by the subsidence of a 
long narrow tract of country, and the surrounding 
