Anticyclones and S.A. Weather. 6i 



rains increase in intensity and advance further and further inland 

 till January, when they are at their maximum and extend almost to 

 the West Coast. During the same period the S.W. borne rains have 

 been steadily decreasing in intensity and receding, as it were, before 

 the advancing S.E. rains, till in January they are at a minimum, and 

 are confined practically to the extreme South Coast. 



After January the S.E. borne rains steadily decrease in intensity 

 and recede towards the east till July, when they are at a minimum, 

 and are confined to small areas near the S.E. Coast. During the 

 same period the S.W. borne rains have steadily been advancing 

 towards the east and increasing in intensity till the maximum is 

 again reached in August. The facts are summed up by saying that 

 " summer rains" advance from the S.E., commence about August, 

 increase in intensity and scope till January (height of summer) and 

 decline from then till August. In direct opposition, " winter rains " 

 advance from S.W., are at a minimum in January, increase in intensity 

 till a maximum is reached in August, and then decline till January. 

 In this description we have a very complete picture presented to us 

 of the thrusting backwards and forwards of rain-bearing systems with 

 their characteristic S.E. or S.W. winds, and of the consequent 

 increase and decrease of the rainfall over the areas which they traverse. 

 If we imagine the Atlantic and Australian anti-cyclones to have any 

 influence in the matter — powerful weather-controls as we know all 

 such systems to be — it requires nothing more than to allow that they 

 have a seasonal progressive movement in order to make the above 

 variations in South African rainfall quite clear to us. 



We have now passed in review many of the prominent 

 characteristics of our weather on this vast continent, and have found 

 that whatever portion of it we examine, and whether we consider 

 the winds, rainfall, pressure, clouds or humidity which prevail over 

 it, they all support the theory which has been advanced, that they are 

 under the direct control of the two great anti-cyclonic systems, and 

 are influenced by their progressive movements. Before long we may 

 hope to see dailv charts illustrating their movements on to the land 

 in winter, and off i: on to the ocean in summer, enabling reliable 

 forecasts to be made of such important points as the arrival of the 

 dry and wet seasons, and of the frosts, all of which depend on the 

 anti-cyclonic movements. When that day arrives we may look 

 forward with confidence to discovering the connection between the 

 winds experienced here, and the monsoons in India, with their all- 

 important effects on the rainy season. It is in the hope of hastening 

 that day, and of contributing, perhaps, towards the solution of some 

 of the problems which are at present obscure, that this paper has been 

 prepared. 



