388 



NATURE 



[November i8, 1920 



The Bulawayo Meeting of the South African Association. 



THE eighteenth annual session of the ijouth 

 African Association for the Advancement of 

 Scier.ce was held in Bulawayo, Southern Rhodesia, 

 on July 14-17, with Dr. I. B. Pole Evans as 

 presiderit. There were the usual receptions .'ind 

 functions, together with visits to the Khami ruins, 

 the Matoppos, the X'ictoria Falls, and IJvingstone. 

 A party, after the conclusion of the official meeting, 

 visited the Great Zimbabwe. 



More than si.\ty papers were read in the various 

 Sections, and the' attendance was a large one, more 

 than 130 members proceeding by special train from 

 the Transvaal, as well as some from the Cape Penin- 

 sula and Natal. 



The president. Dr. I. B. Pole Evans, Chief of the 

 Division of Botany and Director of the Botanical 

 Survey of the Union, gave a most interesting address 

 on "The Veld: Its Resources and Dangers," the 

 address being illustrated by a series of beautiful 

 lantern-slides. He reviewed recent progress in 

 botanical knowledge, and outlined the notable 

 advance that had been made by the members of the 

 I^otanical Survey in respect to systematic ecology, 

 indigenous grasses, fungi, and poisonous plants. By 

 "veld" is meant the natural vegetation of the 

 country. The botanical regions correspond to a large 

 extent' with the geological formations, and nineteen 

 tvpes of veld, each with its own characteristic flora, 

 can be identified. An outline was given of the geo- 

 graphical and geological features, climatic conditions, 

 predominant flora, and plants of economic import- 

 ance of each region. The grasses, poisonous plants, 

 and those yielding drugs, fibres, oil, rubber, timber, 

 and tanning materials, were noted. The need for co- 

 operation among workers in different fields of research 

 was strongly urged, and was illustrated by reference 

 to the co-operation of botanists and veterinarians in 

 the elucidation of certain stock diseases due to 

 poisonous plants. The need for the closer association 

 of the botanist and chemist for the investigation of 

 various problems in animal nutrition was indicated. 

 In conclusion, the president stated: "The investiga- 

 tion of such questions is of enormous importance from 

 an economic point of view, and when such problems 

 are scientifically ard svstematically attacked the veld 

 will yield a hundredfold its present resources, and its 

 dangers will correspondinglv decrease and diminish." 



Mr. H. E. Wood, of " the Union Observatory, 

 Johannesburg, as president of Section A, gave an 

 address on "Recent Progress in Astronomv," noting 

 that the present vear was the centenary of the founda- 

 tion of the Royal Observatory at the Cape. -A very 

 interesting comparison of the astronomical knowledge 

 of a hundred vears a^o with that of the present day 

 ■was given. The problem of the measurement of the 

 distance of the stars bv various methods was outlined, 

 and the rapid progress due to the use of the blink 

 microscope described. S.x\ account of the helium stars, 

 of the behaviour of the variable stars, and of the 

 important results accruing from the combined in- 

 vestigation of their absolute .magnitude and spectro- 

 scopic constitution was given. 



" Geologrv in Relation to Mining " was the subject 

 of The presidential address to Section B, given by 

 Mr. F. P. Mennell, who has seen all the later 

 developments in the mining industry of Rhodesia. \ 

 detailed account was given of the ways in which the 

 economic geologist could aid countries like the Union 

 of South .\frica and Rhodesia by showing that their 

 internal resources were sufficient in kind and amount 

 to form the basis of essential industries without over- 



NO. 2664, VOL". I0'6] 



seas aid. Gold, chromile, coal, zinc, iron, and 

 copper are present, and in the production of chromite 

 Rhodesia leads the world. The structure of the 

 Rhodesian gold-bearing rocks and its influence on 

 the development of such reefs industrially were set 

 forth. In conclusion, it was pointed out that the 

 mining industry led to the manufacture of such pro- 

 ducts as pipes, wire, and chemicals on the spot, and 

 so to the establishment of local industries. 



Dr. T. R. Sim, late Government Forester in Natal, 

 delivered the presidential address to Section C on 

 "Causes Leading towards Progressive Evolution of 

 the Flora of South Africa." He showed that change 

 in the flora was continuously going on, and that there 

 was an interaction between flora and climate. These 

 interactions cause a definite trend, not necessarily in 

 the direction of new species, but in the gradual dis- 

 appearance of what were climax types. The influence 

 of cultivation, bush-cutting, and climatology on flora 

 was considered, while sun-spot cycles and rainfall 

 cycles were described in considerable detail By the pre- 

 vention of grass-burning, by forest maintenance, and 

 by increasing the area under exotic trees the amount 

 of moisture retained and reprecipitated could be 

 vastly increased ; therebv a more temperate method 

 of rainfall would result, and consequently less erosion 

 of the soil occur. 



In Section D the presidential address was delivered 

 by Mr. C. W. Mally, Cape Entomolofrist, whose sub- 

 ject was " Some Zoological Factors in the Economic 

 Development of South Africa." The need for a 

 zoological survey of the Union was mentioned, and 

 the problem of the blending of white and coloured races 

 was discussed and disapproved. The problem of "big 

 game " was considered. Entomological research in 

 relation to human and animal diseases and to agri- 

 culture was outlined, and the insect pests of maize, 

 wheat, and olives were described. Fluctuations in 

 the relative abundance of insects over various periods 

 appeared to be more or less inexplicable. Kn account 

 was given of some results achieved in combating 

 insect pests of crops bv the use of insecticides and 

 natural enemies. .\ plea for adequately trained men 

 for scientific research in South Africa concluded the 

 address. 



The Rev. H. .-\. Junod. president of Section E, 

 gave a most interesting address on "The Magic Con- 

 ception of Nature among Bantus." He outlined the 

 peculiar difficulties in connection with the mentality 

 of natives, and showed the necessity for a proper 

 knowledge of their laws and customs by the dominant 

 race. The Bantu mind does not concern itself with 

 causes, but believes that any abnormal phenornena 

 such as drought or disease are produced by spiritual 

 agents who possess the power of witchcraft. 

 Numerous interesting examples of the reasoning by 

 analogv of the Bantu were given, and a demon- 

 stration of the native magic practice of "bone- 

 throwing," together with a most interesting explana- 

 tion of the svmbolism, was presented. This ingrained 

 magic conception was the stumbling-block to Bantu 

 progress. 



" Labour Conditions in South .Africa " was the sub- 

 iect of Prof. R. Lehfeldt's presidential address to 

 Section F. The problem is complicated by the 

 presence of many natives. The sharp barrier between 

 the races leads to the production of the " poor white " 

 class, who become destitute "and lazy while clinging 

 to the remains of racial pride. The same condition 

 prevents the more intelligent members of the native 

 races from rising. Rural colonies failed for various 



