THE NGAMI. '57 



nak'le we found to be so clear, cold, and soft, the higher 

 we ascended, that the idea of melting snow was suggested 

 to our minds. We found this region, with regard to that 

 from which we had come, to be clearly a hollow, the lowest 

 point being Lake Kumadau ; the point of the ebullition. 

 of water, as shown by one of Newman's barometric 

 thermometers, was only between 2.oj\° and 206 , giving 

 an elevation of not much more than two thousand feet 

 above the level of the sea. We had descended above 

 two thousand feet in coming to it from Kolobeng. It is the 

 southern and lowest part of the great river system beyond,, 

 in which large tracts of country are inundated annually 

 by tropical rains, hereafter to be described.- A little of 

 thatjWater, which in the countries farther north produces 

 inundation, comes as far south as 20 20', the latitude 

 of the upper end of the lake, and, instead of flooding the 

 country,- falls into the lake as into a reservoir. It begins to- 

 flow down the Bmbarrah, which divides into the rivers Tzo- 

 and Teoughe. The Tzo divides into the Tamunak'le and 

 Mababe ; the Tamunak'le discharges itself into the Zouga,, 

 and the Teoughe into the lake. The flow begins either 

 in March or April, and the descending waters find the 

 channels of all these rivers dried out, except in certain 

 pools in their beds, which have long dry spaces between, 

 them. The lake itself is very low. The Zouga is but a 

 prolongation of the Tamunak'le, and an arm of the lake 

 reaches up to the point where the one ends and the other 

 begins. This last is narrow and shallow, while the Zougai 

 is broad and deep. The narrow arm of the lake, which 

 on the map looks like a continuation of the Zouga, has 

 never been observed to flow either way. It is as stagnant 

 as the lake itself. 



The Teoughe and Tamunak'le, being essentially the 

 same river, and receiving their supplies from the same- 

 source (the Bmbarrah or Varra), can never outrun each 

 other. If either could, or if the Teoughe could fill the lake 

 — a thing which has never happened in modern times — 

 then this little arm would prove a convenient escapement 

 to prevent inundation. If the lake ever becomes lower 

 than the bed of the Zouga, a little of the water of the 

 Tamunak'le might flow into it instead of down the Zouga ;: 

 we should then have the phenomenon of a river flowing 

 two ways ; but this has never been observed to take place 

 here, and it is doubtful if it ever can occur in this locality. 



