t8o the desiccation of AFRICA. 



observations, and, as everyone knew who had had experience 

 with observations made with such instruments, no matter what 

 precautions were taken, such levels were liable to very great 

 errors, and, in vievv' of the very small difference in altitude, on 

 which Professor Schwarz based his scheme, extreme caution was 

 necessary in accepting such data. 



The third section of the paper dealt with the partial 

 restoration of Professor Schwarz's Proto-Orange River drainage 

 system., and this was, to a large extent, an engineering question. 

 The entire absence of reliable levels had already been referred 

 to and it is impossible to criticise many of the far-rea6hing 

 engineering proposals made without having essential data of this 

 kind. It has already been stated that, in so far as the proposal 

 to divert the Kunene into the Okavango system is concerned, the 

 proposals appear to be impracticable, and this raises many 

 misgivings regarding the practicability, ifrom an engineering point 

 of view, of the proposals concerning the Zambesi River and its 

 tributaries. 



Another matter which is oil 'thei utmost limportance in 

 connection with the proposals is the availability of sufficient 

 volumes of water to be derived from the Kunene, Okovango and 

 other drainage areas, which would be required for the purpose, 

 firstly of creating an enormously enlarged Etosha Lake, which, 

 according to Proifessor Schwarz, would attain a depth of over 70 

 feet, and, secondly, of recreating the Makarikari Lake, the 

 superficial area of which he estimates at 15,000 square miles. 



The extensive knowledge which we have now in our 

 possession relating to the percentage of rainfall which runs from 

 a given area in the form of stream flow, clearly demonstrates 

 that the enormous volumes of water required to give practical 

 effect to this sdheme would rarely or even never be forthcoming, 

 and, in this case, far from achieving the objects desired, the 

 proposed works would merely lead to the creation of vast salt 

 deserts and swamps. To engineering and technical difficulties, 

 such as referred to above, must, of course, be added very great 

 politico-economic difficulties, and also what Professor Schwarz, 

 in his resume, euphemistically described as sentimental difficul- 

 ties. Supposing, however, for the moment, that it were possible 

 to carry out the sc'heme, and that the vast inland seas in the 

 northern South-West Protectorate and in the Kalahari or the 

 Bechuanaland Protectorate came into existence, we then come to 

 the most important section of the paper, namely, the advantages 

 which would be derived from the scheme. It is clear that, in plac- 

 ing such an enormous scheme before the people of the Union of 

 South Africa, which, it must be said, would certainly cost a vastly 

 greater amount of money than Professor Schwarz appears to 

 imagine, assured benefits of a far-reaching and very sub- 

 stantial character would be demanded. 



The main results claimed for the scheme by Professor 

 Schwarz are the pronounced amelioration of climatic conditions 

 in the arid parts of the Union, more especially the Karroo, and, 



