66 
THE NGAMI. 
Chap. III. 
its north-west extremity. We could detect no horizon where we 
stood looking S.S.W.; nor coidd we form any idea of the extent 
of the lake except from the reports of the inhabitants of the dis¬ 
trict ; and, as they professed to go round it in thi'ee days, allowing 
twenty-five miles a-day would make it seventy-five, or less than 
seventy geograpliical miles in circumference. Other guesses have 
been made since as to its circumference, ranging between seventy 
and one hundred miles. It is shallow, for I subsequently saw a 
native punting liis canoe over seven or eight miles of the north¬ 
east end; it can never, therefore, be of much value as a com¬ 
mercial liighway. In fact, during the months preceding the 
annual supply of water from the north, the lake is so shallow that 
it is with difficulty cattle can approach the water tlrrough the 
boggy, reedy banks. These are low on aU sides, but on the west 
there is a space devoid of trees, showing that the waters have 
retired thence at no very ancient date. Tins is another of the 
proofs of desiccation met with so abundantly tlnoughout the 
whole country. A number of dead trees lie on tliis space, some 
of them embedded in the mud, right in the water. We were 
informed by the Bayeiye, who Live on the lake, that, when the 
annual inundation begins, not only trees of great size, but ante¬ 
lopes, as the springbuck and tsessebe {Acronotm lunata), are 
swept down by its rusliing waters; the trees are gradually 
driven by the winds to the opposite side, and become embedded 
in mud. 
The water of the lake is perfectly fresh when full, but brackish 
when low; and that coming doTO the Tamunak’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 wliich we had come, to be clearly 
a hollow, the lowest point being Lake Kumadau; the point of the 
ebulhtion of water, as shown by one of Newman’s barometric ther¬ 
mometers, was only between 207^° 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 httle of 
that water, which in the countries farther north produces inunda- 
