SOUTHERN AFRICA. 91 
fand-ftone, regularly difpofed in every part, fliewed them to be 
the efFe£t of water and not of fire. This part of the defert 
was more ftcrile and naked than had yet occurred. Scarcely a 
plant of any defcription threw its feeble leaves out of the 
flaty furface, except a few fpecies of the mefembryanthemum, 
among which was one more luxuriant than the reft, whofe 
leather-like covering of its flefhy cylindrical leaves ferved our 
Hottentots, when dried, for tinder. 
About ten miles beyond the Buffalo river we encamped for 
the night upon the banks of a fmall running brook called Geel- 
beckj winding round a flat fandy marfh overgrown with ruflies, 
and abounding with fprings whofe waters were ftrongly im- 
pregnated with fait. All the naked fandy patches were thinly 
fprinkled over with a fine white powdery fubftance not unlike 
fnow : it was found in the greateft quantities where the cattle 
of travellers had been tied up at nights ; and it was obferved 
almoft invariably to furround the roots of a fruitefcent plant 
that grew here in great exuberance. I colleded a quantity of 
this white powder, together with the fand, and by boiling the 
folution and evaporating the water, obtained from it chryftals 
of pure prifmatic nitre. A fmall proportion of a different alka- 
line fait was alfo extraded from the liquor. The plant alluded 
to was a fpecies of falfola, or falt-wort, with very minute 
flefhy leaves clofely furrounding the woody branches. It is 
known to the country-people by the Hottentot name of Camia, 
and is that plant from the aflies of which almoft all the foap, 
that is ufed in the colony, is made. Thefe afhes, when care- 
fully burnt and colleded, are a pure white cauftic alkali, a 
N 2 folution 
