204 A. G. Hoivard.— The JVi?iter Storms of S. Africa, [Sept. 28, 



currents, and saw cirrus cloud at a great height above him floating 

 from the equator. 



But we in South Africa are very differently situated to what Smvthe 

 ■was at Teneriffe. 



The belt of high pressure, which I mentioned before as being about 

 this latitude, is where the upper current reaches the level of the earth, 

 and as this belt is south of us during the summer, and abreast of us 

 ■during winter, the return current cannot be very high up. From 

 •observations, I have come to the conclusion that the summer level of the 

 lower portion of this current is about 3,000 feet above the sea, or 

 slightly higher than the top of the Lion's Head. Tai)le Mountain 

 and most of the peaks of that range penetrate into this current, which 

 is the cause of the table cloth being spread over these mountaius when 

 the south-east wind blows, of which I will speak more anon. 



Now the altitude above sea level at which this return current 

 i\dll be reached depends greatly upon the nature of the country. A 

 .gently sloping land surface, gradually increasing in altitude as the 

 centre of the country is reached, repeats itself at the lower surface 

 of this current. Thus the height from the land surface at Kimberley 

 to this upper current will be approximately the same as at Port 

 Nolloth which is at the sea level. This can be proved by noticing 

 that the same cyclonic movements which affect the lower stratum of 

 our atmosphere are felt at all the stations over Cape Colony, although 

 isome of those stations are over 4,000 feet above the sea level, whereas 

 ■did the return current flow at an uniform level, it would flow round the 

 Colony like water round a rock, and the atmospheric conditions of 

 •high stations would be totally different to those at sea level ; and this, 

 most certainly, is never the case. 



But where there is an isolated peak the conditions are different, as 

 in this case there is no gently graduated contour of ground, but an 

 abrupt elevation round which the atmosphere flows ; thus the atmos- 

 pheric phenomena may be entirely different at the apex of such a peak 

 to what they are at the base. 



Cape Point is such a peak, standing up about 816 feet above sea 

 level, and offering itself as an indicator of coming storms to those who 

 Avill take the trouble to investigate what its warnings portend. 



Before going any furi.her we must come to some decided under- 

 standing as to the physical conditions of a cyclone. What is a cyclone ? 

 A cyclone is a portion of our atmosphere where the winds circle round 

 n definite centre ; at this centre the barometer reads lowest, and at 



