240 A. G. Hoivard.— The [May 4, 



of a high pressure wedge, the elongated area of low pressure over 

 the Colony is split in two, one portion of which recedes to the north, 

 and the other as a cyclone rolls oif to the east, bringing storms to 

 Natal and the Eastern Province. 



Sometimes the northern current flows right across the Colony, the 

 area of low pressure being driven down to the south-east of us. 

 Then if the south current sets in the two will coalesce, and a very 

 high so-called anti-cyclone be the result. I need scarcely explain 

 that Avhen two currents, flowing in comparatively the same direction, 

 coalesce, the pressure is increased without any cyclonic movement, 

 but when the two currents are opposed, a low pressure area is the 

 result, and often independent cyclones are formed. 



When the upper north-west equatorial current is intense it flows 

 down into the area of low pressure to the south of us with great force, 

 and meeting the polar current, drives it back, a storm being the result, 

 the north-west wind blowing straight to the lowest pressure, and the 

 south-east winds being cyclonic. As soon as this current has 

 expended its force, and the polar current becomes banked up and 

 increased in intensity, a return oscillation (as before described) takes 

 place, the distance to which this return storm pushes to the north 

 being proportionate to the intensity of the north-west upper current 

 in the first place. These storms come on to the Colony from the 

 south-west, and even west, and are preceded by easterly and north- 

 easterly winds of no very great intensity. As the area of low 

 pressure advances the wind becomes more northerly, till when the 

 barometer is at its lowest, the wind is generally north-west, but goes 

 round very smartly to the west. This change is usually accompanied 

 by heavy squalls and rain. 



To more fully explain the nature of storms, and how they are 

 generated by two opposing currents, I have prepared some diagrams, 

 Avhich I will now refer to. 



Fig. 1 shews a section through a storm on the plane of the line 

 of motion. 



B M 



D 



(Fig 1.) 



