83 
this, I am told, actually occurred in 1899. The annual rise of this 
river-system is, therefore, in no way dependent on the local rainfall 
(which is very limited), and occurs in the middle of the driest 
season of the year, flooding large areas of country. The Botletli 
iver, where it has become a dry channel with occasional pools 
mysteriously rises by subterraneous percolation before the flood 
reaches it. 
light sandy soil, varied at times by undulating sand-dunes. There 
1s very little outcrop of rock ; walls of limestone appear in places 
“ thirsts,” which are held in so much dread alike by whiteman and 
black. The worst “ thirsts ” (viz. treks between water-pits) of “the 
Great Thirstland ” are, however, found in the Southern Kalahari 
Desert. The water-pits tap the catchment areas in a limestone 
formation, or more often ina sandstone formation with perhaps a 
surface stratum of limestone.* They vary in form and daily 
yield from a semi-open pit capable of yielding sufficient water for 
one or more spans of oxen maddened by the previous “ thirst,” to a 
Bushmen’s sucking-pit where each drop is obtained only through a 
suction reed, and a white traveller is grateful for it secondhand 
from the mouth of a naked savage!t Needless to say this water- 
less country is practically uninhabited by man, while the larger 
mammals, such as the giraffe, eland, gemsbuck and other antelope, 
either travel very great distances to water, or sustain themselves 
during the dry season on the desert water-melons ( Citrullus vulgaris) 
and succulent roots. Even the melons are very local and uncertain, 
and for many months of the long, dry African winter, when there 
18 no dew in the Desert, the wild game gets no water whatever. 
Even the local breed of domestic sheep and goats can exist for 
Months without water, and still retain condition. 
The few humans that are found in the heart of the Desert are 
the so-called Bushmen. The dwarf Bushmen, the true aborigines 
of this country, are practically extinct or are only found far to the 
south. As Dr. 8. Schénland said in his paper before the South 
* Vide Paper read by Dr. S. Passarge at the Berlin Geographical Society, 
April, 1899, ; 
+ Vide Livingstone’s Travels in South Africa, page 51. 
12610 
AQ 
