236 A. G. Howard.-^The [May 4,, 



The word anti-cyclone I do not like at all, as the area of high 

 pressure so called is caused by an advancing current which is opposed 

 by another one, as will be seen in the body of the paper. I prefer the 

 term " high pressure area," which does not give any inference beyond 

 assuming that there must be " low pressure" ones, which is true, while 

 the term "anti-cyclone " infers the existence of prevailing " cyclones,"' 

 while the truth is, that most of our storms are not entirely cyclonic. 



Another theory which has been put forward, is the centripetal one. 

 In this, the area of lowest pressure is assumed to be very small, and 

 the winds to blow straight towards this point from all sides, the only 

 modification being due to the earth's revolution. Thus the very large 

 storms which cross the Indian Ocean would have the winds blowing 

 spirally towards the centre, while the smaller tornadoes of North 

 America would not shew this spiral development at all. 



Here again the whole truth is not grasped. Spiral winds do blow,, 

 but they are not general. In tornadoes the wind, I believe, does blow 

 straight to the centre, but on this point I cannot speak with any 

 degree of certainty. 



Another theory is to consider the area of lowest pressure as almost 

 a line, the winds blowing straight towards it from all points. This 

 theory is true only for equatorial winds ; for polar winds it is utterly 

 at fault. 



I have tried to set forth in the following paper a theory based upon 

 the siftings of all these theories. 



In investigating the question of Storms in South Africa, I have 

 tried all the theories, but find each one unsatisfactory. I have thus^ 

 upon due consideration, placed the whole of them on one side, and 

 endeavoured, from actual observation and deduction, to arrive at a 

 true understanding of this question, using the deserted theories as 

 stepping stones to reach the result which I have tried to make clear 

 in the following pages. 



THE STORMS OF SOUTH AFRICA. 



I wish, before entering into the question of the nature and origin' 

 of Storms, to have it distinctly understood what is meant by the term 

 ** storm." A storm is nothing more than an atmospheric movement 

 tending to restore a ruptured equilibrium. Every loss of equilibrium, 

 of however slight a nature, generates a storm in the strict sense of 

 the word, alth'^ugh the winds evolved may be only slight. I say 

 advisedly, an atmospheric movement, although I am aware many wilU 



