68 SCIENCE IN AFRICA 



were engaged in this work, and the field staif in 1936 included 

 twenty-two geologists whose efforts were chiefly directed towards 

 traversing, and ten prospectors who were engaged in the trench- 

 ing of mineral discoveries. In addition, 679 natives were working 

 under the direction of the thirty-two Europeans. The staff is still 

 maintained at about that strength and with its aid the concession 

 areas are being mapped by parallel traverses one quarter of a 

 mile or less apart, between base lines. All rock outcrops are 

 examined and their positions located on the map; all streams are 

 systematically panned, and in areas where streams contain gold, 

 much soil-panning is done and all favourable-looking rocks are 

 crushed and panned. In the course of a year, several thousand 

 samples from occurrences of economic minerals are assayed in the 

 central laboratory. Each month, a progress map on the scale of 

 2 inches to i mile and a brief report is submitted by each member 

 of the field staff, and the data are compiled on map sheets on the 

 scale of I inch to 2 miles at headquarters. 



To date, more than half the territory has been mapped topo- 

 graphically and geologically, and it is claimed that no portion of 

 the earth's surface of similar area has been more thoroughly 

 searched for occurrences of economic minerals. The development 

 of the copper, manganese, and cobalt deposits are direct results of 

 the activities of these companies. The information obtained is the 

 property of the companies, but topographical data have been sup- 

 plied freely to the government, and it is hoped that before long 

 copies of the geological map-sheets will also be available for general 

 use. 



For the British territories other than South Africa and the 

 Rhodesias, the Mineral Resources Department of the Imperial Institute 

 in London serves important functions in supplying information 

 and other assistance in relation to the marketing of minerals, the 

 commercial valuation of oils and similar subjects. Such an arrange- 

 ment will be indispensable until the individual departments have 

 either grown much larger or have been amalgamated so that ample 

 specialist work is provided for in Africa, and until special officers 

 are appointed to keep in touch with the markets in Europe, as has 

 been done in South Africa and Tanganyika. 



