SURVEYS AND MAPS 4 1 



of the world. The British territories, other than Northern Rhodesia 

 and Nyasaland, and most of the non-British areas have completed 

 a primary triangulation network over the more important areas, 

 and some secondary and tertiary triangulation has been done, so 

 that maps can be drawn individually, but there is little to connect 

 these separate pieces of work. Thus Sierra Leone, the Gold Coast, 

 and Nigeria have reasonably accurate maps which are in no way 

 correlated across the intervening French territories. 



In certain noteworthy instances international co-operation has 

 led to the thorough demarcation of boundaries on a geodetic basis, 

 such, for instance, as the Congo-Angola boundary, the Congo- 

 Uganda boundary surveyed in 1908, and the boundary between 

 the Anglo-Egyptian Sudan and French Equatorial Africa, settled 

 in 192 1-3. But many international boundaries are ill-defined, and 

 there are cases on record where points fixed astronomically many 

 years ago have been found recently to be as much as 10 or 20 

 kilometres in error. It is obvious that, should mineral resources be 

 discovered in the neighbourhood of international boundaries, 

 errors of this magnitude may lead to difficulties; but a much more 

 potent reason for proceeding immediately with geodetic triangula- 

 tion is that the lack of framework has held back topographical and 

 cadastral work. 



The geodetic work essential as a preliminary to an adequate sur- 

 vey of Africa comprises two or three meridional chains and at least 

 as many parallels at right angles to them, cutting across all inter- 

 national boundaries. In the immediate future the piece of work 

 which demands attention is the completion of the arc of the 30th 

 meridian. Later the parallel of 10° north may be looked to, 

 passing through French Guinea, Sierra Leone, the Gold Coast, 

 Togoland, Dahomey, Nigeria, the Cameroons, the French Sudan, 

 Abyssinia, British Somaliland, and Italian Somaliland. A chain 

 of triangulation fixed along this parallel will greatly assist the de- 

 marcation of the boundaries. It is worth noting that the present 

 programme of the Gold Coast survey department includes the 

 measurement of a chain of triangulation between Wa and Gam- 

 baga in the northern territories, lying between the loth and nth 

 parallels. 



In recent years British policy has been to regard geodetic tri- 



