TEMPERATURE °F 



Figure 3. 

 Mean diurnal curves for January and July 



month of the year. Such a representation is shown in Fig. 3, for the extreme months 

 January and July, which are the hottest and coolest months respectively. 



From Fig. 3 it may be concluded that at Chukwani in January light outdoor work 

 is likely to be impossible during the whole day, while even in July work is likely to 

 be impossible during the hours of the afternoon. 



If such a diagram is drawn for each month of the year, for any place, we can 

 from these come to a conclusion as to the number of months of the year in which 

 work is possible during the day. From Fig. 3 it seems safe to conclude that Chuk- 

 wani is not a pleasant place for the white man to settle in. 



Data for Khartoum are also shown in Fig. 2, and appear to indicate that in the 

 months from May to October active work is likely to be trying for the white man 

 during the afternoon. That this is true is confirmed by Mr J.F. Ireland, the Director 

 of the Sudan Meteorological Service. 



The method outlined above in Figs. 2 and 3 can readily be applied to relate the 

 problems of white settlement to climatological conditions. My friend and former 

 pupil Dr S. P. Jackson, of the Department of Geography at the University of the Wit- 

 watersrand, has carried this method of analysis to its logical conclusion and has 

 given a map of Africa south of about latitude 12°N, on which is indicated those 



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