EPPECTS OF FOREST VEGETATION 01^ CLIMATE. 201 



entirely cleared of timber, while in the more sequestered spots, 

 where they have their outposts, the same work of destruction 

 goes on. Thus, of whole forests where the giraffe aiid elephant 

 were formerly wont to seek their daily food, nothiug is now left 

 but a few stumps of the camel thorn, which bea.r a silent testi- 

 mony to the wastefulness of the Bechuana. '-' « # # 



" It appears certain that the further we proceed vrestward 

 from the moiuitains of Natal and Kaffirland the less becomes 

 the amount of rain bestowed by the clouds. The more denuded 

 of trees and brushwood, and the more arid the land becomes, the 

 smaller the supply of water from the atmosphere. The greater 

 the extent of heated surface over which the partially exhausted 

 clouds have to pass, the more rarified the vapour contained in them 

 necessa-rily becomes, and the higher the position which the clouds 

 themselves assume in the atmosphere under the influence of the 

 radiating caloric ; consequently the smaller the chance of the 

 descent of any rain on the thirsty soil beneath, and the more the 

 short-sighted colonist and ignorant natives burn the grass and 

 timber, the wider the area of the heated surface is made ; the 

 further the droughted region extends, the smaller become the 

 fountain supplies and the more attenuated the streams, till they 

 finally evaporate and disappear altogether. Thus the evil 

 advances in an increasing ratio, and unless checked mti'St 

 advance, and will finally end in the depopulation and entire 

 abandonment of many spots once thickly peopled, fertile, and 

 productive." 



" In the case of the fountains at Griqua Town as having 

 formerly poured forth an abundant supply of water, the accidental 

 destruction of whole plains of the wild oHve tree by fire near the 

 town, and the removal of the shrubs on the neighbouring heights, 

 are known to have preceded the diminution of rain, and sub- 

 sequent diminution of springs, the subterranean caverns which 

 acted as reservoirs in the bowels of the earth ceasing to be 

 supplied from the clouds. There can be no question that, 

 hitherto, vegetation, like animal life, has, in South Africa, been 

 wastefuUy and ignorantly destroyed, in direct viokttion of physical 

 laws, which can never be broken with impunity ; and if we com- 

 pare what is now taking place there with what has transpired in 

 other arid countries, our conviction must deepen that it is not so 

 much to the waywardness of Nature as to the wilfulness of man 

 that we must assign the recent extension of the Kalahari 

 Desert." 



To those remarks the author adds references to other regions 

 beyond Africa, some of which have not yet been mentioned by 

 myself. For instance he names a case (^mentioned in Chambers's 

 Journal, July 4, 1868), where 400 springs in one small province 

 of Persia, had failed ; '' the fatal consequence of permitting the 



