XIX THE RIFT VALLPIY AND ITS LAKES 251 



increases the s[)ecitic gravity of the water. Tims, the 

 water of tlic Dead Sea whieh lies 1300 feet l)elow the 

 level of the Mediterranean Sea, contains 25 per cent, of 

 solids. The water of Salt Lake, Utah, has a])out the 

 same proportion of solids. Lake Nakuru is in a similar 

 condition. Lake Rudolf is probably undergoing a like 

 change, due to the prolonged dr(jugiit whieh has affected 

 the northern section of the Eift Valley. 



Siidn L(jl:('s. There is a deposit of natural soda 

 covering an area of thirty square miles, known as Lake 

 IMagadi, at tlie southern end of the eastern arm of the 

 Rift A'alley. The deposit is estimated to contain 

 -!00,000,000 tons of soda ; whenever a portion of the 

 surface soda is removed, it is (piickly repLiced, as though 

 it were pushed up from below. Further south in 

 German territory there exists another soda lake, known 

 as Lake Natron, discovered by Fischer (1883). 



Beferenceb: 



Moore, .J. E. S. ... The Tanganyika Prohlem. London, 1903. 



Oregorjf, .1. W. ... The Great Rift Valley. London, 1896. 



Huxle}', T. H. ... llasisadras Adventure. Essays on Contro- 



verted (.Questions. London, 1892. 



Holmel, L. von ... Discovery of Lakes EiLdolf and Stefanie. 



Translated by Nancy Belt 1894. 



Powell-Cotton, P. H. C In Unknown Africa. London, 1904. 



Smith, A. Donaldson... Thronijh Unknoivn African Countries. 



London, 1897. 



Neumann, A. H. ... Elepha)it Hnnting in. East Equatorial 



Africa. 



