1887.] Storms of South Africa. • 245 



storm of this type is generally from the north, which changes to the 

 north-west as the centre approaches. As the centre passes, which it 

 does to the south of us, the wind chops round to the west with heavy 

 rain and squalls, which continue as the barometer rises. Fine 

 weather follows with a south-west wind. With these storms the 

 greatest amount of rain falls after the centre has passed. 



These depressions bring rain to this end of the Colony during 

 winter and to the other end during summer. Owing to the fact that 

 these storms generally travel alon t he course of the L'Agulhas 

 current, the rain falls in the east Avith a south wind. 



When a depression travels as rapidly as the advance winds blow, a 

 dead calm is very often experienced in front of the storm. 



This is very often the case, especially during summer, when the 

 storms come from the north-west. 



1 have often noticed a gradient between Cape L'Agulhas and Cape 

 Town, which ought to have brought a south-east gale, but only light 

 winds followed, the fact being that the depression, although deep, was 

 travelling as fast towards the east as the advance indraw, in other 

 words it was keeping up with the wind and counteracting its 

 intensity. 



I have assumed in all these examples that the two opposing 

 currents are pressing directly against each other ; but such is very 

 seldom the case, they generally abut obliquely and sometimes very 

 much so, and then instead of travelling in the direction of the line of 

 the minor axis of the low pressure area, they travel along a line 

 formed by the resultant of the two opposing currents, and the form of 

 the depression changes from that of an ellipse to almost any shape. 



And now before concluding, I should like to say a word or two 

 about sun spots, or rather I should say solar storms. It will be 

 remembered that in a former paper of mine, I laid before you the fact, 

 from actual observation, that upon a sun spot reaching the centre of 

 the sun, various known w'nds blew at regular intervals thereafter ; 

 thus from two to three days after, a south-easter was sure to blow 

 during the summer months, while eleven days after, north-west or 

 west winds were experienced. 



Now the reason of this is shewn in this paper. As soon as the 



atmosphere at the equator is affected, an upper current rushes towards 



the poles. It takes two or three days to reach the latitude of Cape 



Colony, at which date the south wind blows strongly owing to the 



.^atmosphere being banked up to the south of us. The upper current 



