324 -M(jDIFICATIOX of south AFRICAN RAINFALL. 



topmost l)ranclies dead Imt the lower branches still li\ing. The 

 lesult was the rise in temperature of the forests. As a result, 

 again, the influence of these forests on the vapoitr-laden breezes 

 diminished, and with the repellent heat rising from the grass- 

 lands, and the forests not exercising their full share in cooling. 

 the precipitation of moisture in the ordinary way — from cloud 

 condensation — became more and more tmcommon. But this did 

 not necessarily lead to the diminishing of the average annual 

 rainfall — it merely changed the manner in which it took place. 

 For as these conditions repelled the precipitation of moisture in 

 soft showers, they brought about those conditions which restilted 

 in thunderstorms, and with the thunderstorms often torrential 

 precipitation. This led to further erosion, and, since the period 

 over which the rain was s])read was lessened, to further running 

 to waste of the water, to further flooding, and to less soakage. 

 This has been going on. gradually, slowly but \ery surely, for a 

 considerable period, and the result has been the entire changing 

 of the condition of the water'-supply of South Africa, and the 

 conversion of a considerable portion into semi-desert or karroo. 

 So, although the average rainfall for a period of years fifty years 

 ago may be practically the same as the average rainfall for the 

 same period of years now, the result of the two rainfalls may be, 

 and is, vastly different. We have only to look at the desiccation 

 W'hich has taken place in all parts of South Africa to see how 

 our utilisable water-supply has diminished. \\"e have, though- 

 out the Karroo and Free State, rivers which to-day are rivers 

 only in name — ma\' of them in the dr}' season but a series of 

 jx)ols. Advocate luigene X. Alarais, writing in the Agricultural 

 Journal, in 1914, of the portion of the Transvaal known as 

 the Waterberg, gives some striking illustrations of the desicca- 

 tion which has taken place in that district. He states: "The 

 two rivers, Ma(jalakzi.'cii (the Stronghold of the Crocodile) and 

 Palala (the Impossible), bearing in their native names proof 

 of their former greatness, are to-day mere ribbands of sand 

 winding through desolate sand-dunes to the Limpopo." And 

 again: "In the north of the district there is a tract of four 

 thousand sciuare miles in extent, in which there is no single 

 drop of water running or stagnant above the surface of the 

 ground." And this in a district in which the same writer 

 states : — 



There was a lime within tlic meiiKjry of white men when every 

 kloof and donga was the hed of a perennial stream nf crystal water, and 

 the district generally was so niarsliy and " vals " as often to render a 

 passage hy ox-wagon a hazardous undertaking. In those days was its 

 present name hestowed on the district (i.e.. the n;ime "Waterberg''). a 

 name tliat to-day seems to have originated in the hitter irony of some 

 disai)pointed voortrekker. 



\'i\i(l though the picture is, it is by no means a unique 

 pictme. On ever\- hand we see the same thing — one-time peren- 

 nial streams converted into dry dongas, except just after a 

 torrential d<>\vn]j(nir. when they are raging tt)rrents. With this 



