344 SECTIONAL TRANSACTIONS.— E. 



In the present paper the method ia therefore applied to the simpler case of horizontal 

 plates, and this leads in turn to some further simplifications in the treatment of inclined 

 plates. Comparison of the respective advantages of horizontal and inclined plates is 

 then made. Lateral extension from aerial bases, and several other minor points are 

 also dealt with. 



Wednesday, July 24. 



Prof. E. Walker. — The Effect of Relief of South Africa on Settlement. 



Main features of relief are (a) unbroken coastline, (b) three more or less definite 

 terraces rising from coast to east-central plateau behind escarpment of Drakensberg 

 and (c) highest edge of this plateau (High Veld) facing south-east. 



Height inland gives level average of yearly temperature in spite of difference of 

 latitude ; hence, possibility of speedy settlement by same kind of people all over it 

 and even further north where ground is high enough, e.g., S. Rhodesia. 



Rivers, plunging down from plateau and terraces, are useless as means of com- 

 munication. This and absence of sea inlets cut off bulk of Union from contact with 

 the sea. Deep river beds do not help the irrigator. 



Summer clouds from south-east give rain to most of Southern Africa. Heavy 

 rainfall in Portuguese East Africa and sub-tropical coast of Zululand-Natal. Malarious 

 back blocks of P.E.A. delayed development there till the coming of Transvaal and 

 Rhodesian gold mines and railways in the 'nineties. Twenty-five inches of rain in 

 Cape Native Territories, Basutoland and eastern Free State and eastern Transvaal. 

 Kaffir wars (1779-1878) and Free State-Basuto wars (1858-68) fought out along this 

 line ; wars for land and not for cattle. Fifteen inches' fall as far west as line running 

 outside Free State and eastern Bechuanaland ; the limit which the late RepubHcs 

 tried to reach. Missionaries' road and railway to Central Africa run near this line, 

 because, for political reasons, they could not go along ' the line of life ' through 

 Transvaal. Kalahari and South- West Africa get very little from south-east clouds. 

 West Coast also misses winter rains brought by north-west winds, and remained 

 unoccupied till diamond discoveries and railways of twentieth century. 



North-west rains catch south-west corner round Cape Town. European penetration 

 began in these ' Mediterranean ' lands in 1662. Formation of agricultural colony by 

 1700 up to first range of mountains thirty miles inland. Sandy Cape Flats made 

 Peninsula an island ; helped division of interest between maritime Cape Peninsula 

 and corn and wine farmers, and development of cattle-farming. Trek Boers became 

 stereotyped in passing round or throiigh barren and high Karroos. By 1770 these 

 frontiersmen were out on to better lands near Fish River. Karroos a barrier between 

 Western and Eastern Cape provinces. 



Two lines of advance in early nineteenth century {a) Continuation of eastward 

 thrust in face of Bantu resistance. Failure of territorial segregation ; no natural 

 frontiers. By 1865 line between Colony and Native Territories fixed at Kei River. 

 (6) Trek Boers swerved north-eastward ; on to the High Veld before 1795 ; Great Trek 

 crossed Orange River 1835-40. High Veld republics : Free State south of Vaal, 

 Potchefstroom, the nucleus of the Transvaal, beyond it. Resistance of tribes helped 

 in the west by lack of surface water, by fever and mountains in the north (Bush Veld), 

 and by mountains in Basutoland to south-east. 



Dominant area of Natal in sub-tropical coast belt. Sugar and Indian labourers. 



Industrial revolution began suddenly in 'seventies. Diamonds and then gold 

 mines and railways invaded Trekkers' refuge on High Veld. Gold in ancient rocks, 

 ooal in overlying shales and sandstones. Rhodes's Pioneers cut Trekkers off from 

 high ground beyond Limpopo. To-day, Trekkers are trekking into the towns. 



Prof. P. Serton. — Economic Development under ' Desert ' Conditions in the 

 Western Karroo. 



1. A considerable area in the Western Karroo has an average annual rainfall of 

 less than 5 inches. The driest part of the Kalahari (in so far as can be judged from 

 the available data) has between 6 and 10 inches. Compare these figures with those 

 for other dry regions on earth. Conclusion : the Western Karroo, though more 

 favoured than e.g. the worst parts of the Sahara, gets as little rain as many regions 

 which are generally considered to be deserts. 



2. Rainfall figures in relation to temperature. Climatic formulas of Koppen 

 and Lang-Hirth. Scarcity of available temperature-records in South Africa. Esti- 



