82 
across the Desert. The symbol of authority, the immediate con- 
trolling force on the spot, is the usual ‘corporal’s guard’ in the 
form of some twenty Basuto police under two European officers 
with ten or twelve: European N.C.O’s. and troopers, The senior 
officer holds a Magistrate’s commission. 
Lake Ngami and the River-system._Lake Ngami, the centre of 
which lies in about Lat. 20° 30’ S. and Long. 22° 50’ E., was first 
discovered by Livingstone and Oswell in 1849. At that time it 
was “a fine-looking sheet of water” some 20 miles long and 10 
wide, and the roar of its waves was said to resemble thunder! But 
during the past half century the process of desiccation* in this 
part of Africa, already apparent in Livingstone’s day,f has pro- 
ceeded so rapidly that Lake Ngami has ceased to be a lake, and is 
now practically dry. It has become a vast expanse of reeds 
_ Broadly speaking, Lake Ngami may be considered the northern 
limit of the Kalahari Desert, and the southern and lowest point to 
the S.W. of an inland river-system which finds no exit to the sea. 
The drainage, therefore, is towards this depres:ion to the S.W., and 
towards the Makarikari Salt-pan which is"at a still lower level 
some two hundred miles to the S.E. Lake Ngami is now in the 
system of the country lying immediately north of Lake Ngami. 
extreme east and west channels, They are essentially the same 
- river, linked up by innumerable channels “so many no one can tell 
itself either into the depression of Lake Ngami, or into the 
Botletli River (as the lower reaches of the Tamalakan are called) 
which ultimately loses itself in the sands of the Desert. No water 
oe “Ess completely silted up, but, in years of exceptional rainfall in 
é countries to the north, the flood brought down by the Tama- 
= = fill up the channel of the Botletli to the south-east and a 
py arm of the Lake (called the “ Lake River ”) linking up the 
er oa sae ghee We may then have the phenomenon of a 
ng flowing two ways, as mentioned by Livingstone ;t — 
* Vide Die Kalahari ; 
j Ye aa Lr 8 Eer, nn 
t Vide Livingstone’s Travels in South A frica, page 67. 
