482 LIFE OF DAVID LIVINGSTONE, LL.D. 



sources of the great rivers that flow to the north in the great Nile valley. 

 The primaries unite and form streams, in general larger than the Isis at 

 Oxford or Avon at Hamilton, and may be called secondary sources. They 

 never dry, but unite again into four lines of drainage, the head waters or 

 mains of the river of Egypt. These four are each called by the natives 

 Lualaba, which, if not too pedantic, may be spoken of as lacustrine rivers, 

 extant specimens of those which, in pre-historic times, abounded in Africa, 

 and which in the south are still called by Bechuanas ' Melapo ;' in the north, 

 by Arabs, ' Wadys;' both words meaning the same thing — river-beds in which 

 no water ever now flows. Two of the four great rivers mentioned fall into 

 the central Lualaba or Webb's Lake River, and then we have but two main 

 lines of drainage as depicted nearly by Ptolemy. 



" The prevailing winds on the watershed are from the south-east. This 

 is easily observed by the direction of the branches ; and the humidity of the 

 climate is apparent in the number of lichens, which make the upland forest 

 look like the mangrove swamps on the coast. 



" In passing over sixty miles of latitude, I waded thirty -two primary 

 sources from calf to waist deep, and requiring from twenty minutes to an 

 hour and a quarter to cross stream and sponge ; this would give about one 

 source to every two miles. 



" A Suaheli friend, in passing along part of the Lake Bangweolo, during 

 six days counted twenty-two from thigh to waist deep. This lake is on the 

 watershed, for the village at which I observed on its north-west shore was a 

 few seconds into 11° south, and its southern shores and springs and rivulets 

 are certainly in 12° south. I tried to cross it, in order to measure the breadth 

 accurately. The first stage to an inhabited island was about twenty-four 

 miles. From the highest point here, the tops of the trees, evidently lifted by 

 the mirage, could be seen on the second stage and the third stage ; the main- 

 land was said to be as far as this beyond it. But my canoe men had stolen 

 the canoe, and got a hint that the real owners were in pursuit, and got into 

 a flurry to return home. ' They would come back for me in a few days 

 truly,' but I had only my coverlet left to hire another craft if they should 

 leave me in this wide expanse of water ; and being four thousand feet above 

 the sea, it was very cold, so I returned. 



" The length of this lake is, at a very moderate estimate, one hundred- 

 and-fifty miles. It gives forth a large body of water in the Luapala ; yet 

 lakes are in no sort sources, for no large river begins in a lake. But this and 

 others serve an important purpose in the phenomena of the Nile. It is one 

 large lake, arid, unlike the Okara — which, according to a Suaheli, who tra- 

 velled long in our company, is three or four lakes run into one huge Victoria 

 Nyanza — gives out a large river, which, on departing out of Moero, is still 

 larger. These men had spent many years east of Okara, and could scarcely 



