386 RbroRT S.A.A. Advancement of Science. 



■of the Coast and the Transkei. does the rainfall exceed 20 inches. 

 This latter portion is irrigated by perennial streams and rivers; 

 si^rings and streams derived from the more moist mountain districts 

 give a supply, which serves for cultivation, to the second ; but over 

 half the area, of the Colony rivers flow for only a few days in the 

 year, and that vast tract of country which, under other climatic 

 conditions, would be as fertile as any in the world, is practically a 

 desert. 



INCREASING DRYNESS. 



This unhappily is not all. There is a notion abroad that the 

 climate is growing still more dry. It is to be met with in papers and 

 books, and in man}- parts of the Colony the older farmers have shewn 

 the author where streams and rivers once ran, and told him of 

 numbers of springs years ago yielding plentiful supplies, which are 

 gradually falling off. Through the observations of rainfall for nearly 

 50 years, and by the help of other records extending over the period 

 of 50 years before that, it can be confidently stated that there 

 is no appreciable diminution in that respect, but there are other 

 causes which will produce a similar effect, and doubtless the 

 change of climate noticed by these old residents is due to them. It 

 is evident tliat if vegetation, which [)revents the fallen rain from im- 

 mediately running off the surface and facilitates its soaking into the 

 soil or the porous rock, is destroyed, and its journey to the nearest 

 channel, which conducts it to a stream which leads to a river, and so 

 to the ocean, is assisted, the country will benefit much less by rain 

 that does fall ; and practices which bring about these results do 

 appear tO' increase year by year. One of these is the burning of the 

 veld, so that young grass may spring uj:* — an ancient custom of doubt- 

 ful benefit to the pasturage but of positive harm to the .springs ; 

 another, the destruction of forests, which, despite the strenuous 

 efforts of the Forest Department to preserve them, seems to go on 

 in some parts of the Colony ; but the principal cause is over-stocking. 

 The evils of over-stocking are not only the too rapid eating down of 

 the grass but the animals, by passing over the same tracks again and 

 again, make shallow channels for the water to run in after rains, and 

 these gradually deepen, not only quickly carrying away the surface 

 water but draining the ground to some extent below the surface, and 

 water which would have penetrated into the earth or have l:)een 

 converted into vapour, to descend again as rain, now is hurried away 

 to the ocean. 



RIVERS AND LAKES. 



The sources of the rivers too are in the interior, where the 

 country becomes drier, and as the scanty rainfall there is not distri- 

 buted over many days in the yeaf, the laii, wiien it does come, is 

 heavy, so that the streams, owing to the sharp slope of the land to the 

 sea, roll in torrents to the coast, but when the floods are past their 



