130 



Report S.A.A. Advancement of Science. 



meteorology, for the Northern Hemisphere, when he says : ' ' On 

 plains or also on highlands the wind shews a tendency to turn with 

 the hands of the clock in the forenoon and the other way in the 

 afternoon." I believe that this particular wind veering is only the 

 beginning of a rotation. For these periods almost invariably are the 

 passages of a low barometer, a high temperature, and a low Relative 

 Humidity to a high barometer, a low temperature and a high Relative 

 Humidity or vice versa. Sometimes they are on a slight rise in a low 

 barometer, sometimes on a slight depression in a high one. On the 

 whole, comparing the various elements connected with a veering wind 

 period in the table given as an appendix to this paper, we see that 

 these East with North wind periods, differ little from the rotating 

 wind periods. These might also be the passages of secondary 

 cyclones or V depressions, with their usual thunderstorms. 

 Observations from other centres would, however, be wanted to decide 

 the point. 



In order to give a more precise idea of the winds of Bulawayo, I 

 have calculated the North and East components of wind frequency 

 and wind movement for the three months of October, 1903 to 1905. 

 The extreme regularity of our climate shown by the traces of the 

 recording instruments allows me to assume that the^ computation for 

 one month only and even in the short period of three years will fairly 

 well bring out the general features of the wind movement. October 

 is besides likely to be the best month to give average results, as it is 

 astride on the two seasons of the year. 



The first three columns of the following Table (A) represent the 

 wind frequency, the next three the combined frequency and movement. 

 The co-efficients for the various directions are in the former the 

 number of times the wind blew in each direction, in the latter the 

 velocity in kilometers per hour for each direction. 



TABLE A. 



Wind frequency Components. 



Hour. 



N. 



E. Resultant. 



69-2 

 70-9 

 64-8 



65-5 

 59*6 

 55-1 

 43*0 

 46-4 

 54-8 

 53*2 

 627 



65-3 

 567 



+ 

 + 

 + 

 + 



Movement Components. 



N. 



267 

 159 

 154 

 214 



369 

 582 



373 

 108 

 158 

 158 



157 

 182 



125 



+ 



+ 



E. 



Res. 



