46 SCIENCE IN AFRICA 



eleven-mile error in the position of an important steel bridge by- 

 mistaking a 19 1 3 mail-runner's path marked on the map for the 

 'great north road' of 1925. 



The old plane-table surveys were incorporated in a series of 

 sheets on a projection reasonably good for the purpose, and on a 

 well thought out numbering and arrangement. But as triangula- 

 tion grows, and as the property surveys come into a rigid frame- 

 work, it becomes important and economical to work upon a more 

 flexible projection. South Africa already has such a system, but 

 has adopted certain methods which are unsuitable for topographi- 

 cal purposes. Accordingly Brigadier MacLeod, after the Confer- 

 ence of Empire Survey Officers in 1931 and again in 1935, put for- 

 ward an alternative method for projection of the 1 1250,000 series, 

 whereby the whole of Africa is divided into meridional belts each 

 representing six degrees of longitude.^ His memorandum on the 

 subject has been circulated to survey departments, etc., and it 

 seems highly desirable that some international agreement should 

 be reached. Commandant Maury has already used a somewhat 

 similar scheme for projection by dividing part of the Belgian Congo 

 into meridional belts. 



It would clearly be desirable that a unified system of map pro- 

 jection should be adopted at an early date by all countries holding 

 territory in Africa. The rate of publication of maps is accelerating 

 so rapidly that a change in the method of projection, say in ten 

 years' time, would entail great cost and perhaps for this reason 

 alone could not be accompUshed. 



This question is closely connected with that of the unit of 

 measurement to be adopted. The international metre is the only 

 unit to which the French, Belgians, Italians, Portuguese, and 

 Spanish Governments are likely to agree. Egypt already uses the 

 metre, and the case for its adoption generally appears to be very 

 strong, as pointed out by Brigadier MacLeod (1936). It would 

 involve certain difficulties in the British territories, where the sur- 

 vey work so far done has been in feet, particularly since, if the 

 metre were adopted, the change would probably have to be ex- 

 tended to cadastral surveys. A full statement of the various argu- 



* 6° belts were unacceptable to Tanganyika, where work is in progress using 

 meridional belts of 5°. 



