THE DESICCATION OF AFRICA. 17 1 



north-east south-west. On the other side of this there are 

 the Madenassa, Haina and Chansi Plateaux, separatmg the 

 Ngami from the Makarikari. The two great hollows are 

 connected by the Botletle River and to the south by, the 

 Omuramba Epurika. 



Lake Ngami is an expansion in the system of inter- 

 communicating canals of the Okavango Delta and lies under 

 the eastern bank of its former basin. Livingstone, who dis- 

 covered the lake on August 1st, 1849, described it as being 

 60 miles wide, and from the writings of Livingstone, Chap- 

 man, Baines and other travellers of that time, the general 

 impression has arisen that Lake Ngami is a respectable sheet 

 of water. In 1897 Passarge found that the water had 

 entirely disappeared and its place taken by a brown expanse 

 of reeds, between the roots of which the traveller sinks into 

 treacherous mud. This was the condition of Lake Kumado 

 in the south of the Makarikari depression in 'Chapman's time, 

 1852, and here the lake has entirely disappeared, a? Ngami 

 will shortly if nothing is done to prevent it. 



Livingstone recognised that Ngami land was once the 

 sight of a vast lake; he came to this conclusion from the 

 prevalence of fresh-water shells in the limestone layers that 

 appear underneafh the sand. He it was, too, who first 

 explained the climatic changes in South Africa as due to the 

 draining of this lake by the Zambesi. Livingstone called it 

 "a breaking through " of the Zambesi, but I have ascribed it 

 to the head-stream erosion of the river. The limits of the 

 two great Kalahari Lakes are shown in the map which I have 

 drawn from that by C. Jurisch, which accompanies Passarge's 

 work on the Kalahari. The limits of the Makarikari are 

 indefinite on the north, for here we have the Gwai Poort, 

 which is the old valley of the Loangwe, before the Zambesi 

 trenched across it. There has been doubt expressed as to 

 whether, if the Makarikari were to be filled up again, the 

 water would not escape by the Gwai Poort, but Chapman is 

 positive that there is a distinct water-shed, separating the 

 two areas. 



The Kwando, Linyanti, or Chobe River, like the 

 Okavango, enters the Ngami depression by a sort of delta, 

 receiving an important tributary from the Okavango which 

 is short-circuiting the water past Lake Ngami and then 

 expands into a vast swamp, through which the water filters 

 into the Zambesi. Livingstone happened to be on the 

 borders of this swamp in i860 and describes how, after a 

 period of drought, the natives were burning the reeds in order 

 to drive out the elephants that fed in the swamps. The 

 chief, Makompa, with his men lying in wait, had killed five 

 elephants and three buffaloes with their spears, as well as 



