Variability of Temperature. 



139 



Table 5. — Variability of Relative Humidity at Kenil worth 

 (Kimberley), 1896 to 1905. 



From Tables 4 and 5 it appears that both the absolute and 

 relative humidities change more from day to day in the height of 

 summer than they do in the depth of winter ; but that, as distin- 

 guished from the temperature variations, the variability of moisture 

 from night to night is considerably greater than that from day to day 

 in respect both to mean and extreme values. This is, to me, a 

 surprising result, considering that the relative humidity has a much 

 wider range by day than by night. 



The object of this brief paper is mainly climatological, but it 

 will not, perhaps, be out of place to glance at some of its meteoro- 

 logical aspects. 



We have said that the inter-diurnal temperature variability on the 

 coast is much greater than it would be if hot and cold winds did 

 not occur. The hot winds have been dealt with elsewhere.* 

 They are still difficult to account for entirely, but enough is known of 

 them to make it certain that they are associated with a definite type 

 of weather, that they originate on the table-land and blow outwards 

 and downwards, and are quite analogous to the foehn winds of 

 Europe, Greenland, and elsewhere. The cold winds of the coast 

 have not yet been discussed, although thq}' are, from a meterological 

 point of view, at least as interesting as the hot winds. 



For the purpose of obtaining a preliminary idea of these cold- 

 weather periods on the coast, I have selected 85 typical cases of low 

 minimum temperature registered in any month during the nine years 



* See Stewart, "The Meteorology of South Africa," Science in Sotith Africa, 

 1905, p. 40; Hann, Met. Zcitschrift, Jan. 1904, p. 42; Sutton, "The Climate 

 of East London," Trans. S.A. Phil. Soc, Vol. XVI., Part 3. 



