SPRINGS AND RIVERS. 6? 



In every salt-pan in the country there is a spring cf 

 water on one side. I can remember no exception to this 

 rule. The water of these springs is brackish, and contains 

 the nitrate of soda. In one instance there are two springs, 

 and one more saltish than the other. If this supply came 

 from beds of rock salt the water would not be drinkable,, 

 as it generally is, and in some instances, where the salt 

 contained in the pan in which these springs appear has 

 been removed by human agency, no fresh deposit occurs. 

 It is therefore probable that these deposits of salt are the 

 remains of the very slightly brackish lakes of antiquity, 

 large portions of which must have been dried out in the 

 general desiccation. We see an instance in Lake Ngami, 

 which when low becomes brackish, and this view seems 

 supported by the fact that the largest quantities of salt 

 have been found in the deepest hollows or lowest valleys,, 

 which have no outlet or outgoing gorge ; and a fountain,, 

 about thirty miles south of the Bamangwato — the tem- 

 perature of which is upwards of ioo° — while strongly 

 impregnated with pure salt, being on a. flat part of the 

 country, is accompanied by no deposit. 



When these deposits occur in a flat tufaceous country 

 like the present, a large space is devoid of vegetation, on 

 account of the nitrates dissolving the tufa, and keeping 

 it in a state unfavourable to the growth of plants. 



We found a great number of wells in this tufa. A place 

 called Matlomagan-yana, or the " Links," is quite a chain 

 of these never-failing springs. As they occasionally 

 become full in seasons when no rain falls, and resemble 

 somewhat in this respect the rivers we have already men- 

 tioned, it is probable they receive some water by perco* 

 lation from the river system in the country beyond. 

 Among these links we found many families of Bushmen ; 

 and, unlike those on the plains of the Kalahari, who are 

 generally of short stature and light-yellow colour, these 

 were tall strapping fellows, of dark complexion. Heat alone 

 does not procfuce blackness of skin, but heat with moisture 

 seems to insure the deepest hue. 



One of these Bushmen, named Shobo, consented to be 

 our guide over the waste between these springs and the 

 country of Sebituane. Shobo gave us no hope of water in 

 less than a month. Providentially, however, we came 

 sooner than we expected to some supplies of rain-water in a 

 chain of pools. It is impossible to convey an idea of the 



