PRESIDENTIAL ADDRESS 755 



that in the colony of the Gold Coast a rigorous survey was rendered imperative 

 by the g;old-miniug boom of 1901. The work was entrusted to Lieut.-Colonel 

 Watherston, C.M.G., E.E. Owing to the dense forest covering practically the 

 whole country triangulation would have been prohibitive in price and very slow 

 in execution. The initial positions were therefore fixed by a network of long 

 traverses, executed with all possible refinements with steel tapes and theodolites. 

 Astronomical latitudes were observed by Talcott's method at every fifty miles. 

 The errors of misclosure of the traverses proved to vary from about 1 in 2,000 in 

 imfavourable cases to nearly 1 in 6,000 — results inferior to triangulation, but 

 at the same time sufficiently accurate to form the basis of a map with no appre- 

 ciable errors on the paper. One great defect of the traverse method of fixing 

 points lies in the practical impossibility of carrying the heights through without 

 occasional checking, either by lines of levels or by trigonometrical observations. 

 Such work makes therefore an imperfect basis for topography, and would only be 

 used when natural features compel its adoption. 



Northern Nigeria is a country of enormous ai-ea, and, up to the present, of 

 small revenue. It has tUerefore not been found possible to allocate the funds for 

 any systematic mapping. The existing maps are compilations based upon 

 sketches made by civil and military officers when travelling upon duty and upon 

 the surveys made by the different Anglo-French and Anglo-German boundary com- 

 missions. In 1905-6 Captain R. Ommaney, R.E., fixed the astronomical lono-itudes 

 of fifteen towns by exchange of telegraphic signals with Lagos. With the aid of 

 these values, combined with a number of astronomical latitudes, it has been 

 possible to combine the material into something like a complete map. It need, 

 however, hardly be pointed out that astronomical fixations are liable to large and 

 imcertain errors, due to the variation of local attraction, and cannot attain the 

 precision of even a rapid triangulation. In Southern Nigeria the experience 

 has been somewhat unfortunate. This colony has spent a very substantial sum 

 upon its survey department, and if the work had been properly organised and 

 systematically carried out we should by now be in possession of a complete map 

 of a large portion of the country. Unluckily, the mistake has been made of 

 detaching survey parties for non-geographical purposes, such as the erection of 

 telegraph lines, work doubtless urgently required in the interests of the colony, 

 but not lying within the sphere of a survey department. Thus systematic 

 progress was rendered impossible, and, though isolated pieces of triangulation and 

 long lengths of traverses have been done, no topographical map of any area yet 

 exists. 



Of the remaining West African colonies the Gambia river is a narrow piece 

 of land with boundaries running parallel to the river banks, and, except for the 

 actual trade along the river, is unimportant. In Sierra Leone the country in the 

 immediate vicinity of Freetown was surveyed by the colonial survey section, a 

 small party employed by the War Office for the purpose of making surveys of 

 places of special military importance. The map of the remainder of the colony is 

 a compilation based on miscellaneous material. 



In the course of this summary of the state of the mapping of British Africa 

 mention has been made of the surveys made by joint commissions appointed for 

 the delimitation of international frontiers. No small part of theiexisting map is 

 due to work of this class. Thus joint Anglo-French commissions have marked 

 out the frontiers of the Gambia, Sierra Leone, the Gold Coast and Nigeria: 

 Anglo-German commissions the eastern boundary of Nigeria, tbe boundaries 

 between British and German East Africa, between German East Africa and 

 North-East Rhodesia from Lake Nyasa to Tanganyika, and between Bechuanaland 

 and German South- West Africa ; Anglo-Portuguese commissions the frontiers 

 between Portuguese East Africa and North-East Rhodesia and Nyasaland respec- 

 tively. Useful surveys have also been made in the course of the mutual 

 demarcation of the frontiers between Abyssinia and the Soudan on the west and 

 British East Africa on the south ; also of the frontier between the colony of 

 Sierra Leone and the Republic of Liberia. ,., 



Important as the work done by these commissions ha? been, its v.nlue would 



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