1885.] Influences and Cyclonic Paths of South Africa. 31 



these places will not be affected by the cyclone, and the in nowise 

 uncommon occurrence of N.E. winds at Natal and East London, S,E. 

 at the Cape, S.W. at Cape L'Agulhas, and W. or N.W. winds at the 

 other coast ports, will be experienced. 



Another source of variation is the almost invariable formation of a 

 secondary against the Atlantic anti-cyclone, which secondary always 

 passes close to Cape Town and intensifies the S. or S.E. wind there 

 and at Cape Point by increasing the gradient. Sometimes a secondary 

 forms on the '* Col," which, becoming an independent cyclone, passes 

 off to the S.E., while the primary travels to the N.E; 



All these conditions make the forecasting of weather round the 

 coast very difficult. 



I am of opinion that sometimes this ''Col" is absent for several 

 days at a time, and if during that period a cyclone approaches it is 

 sure to pass to the S. or S.E. The centre of a cyclone travelling from 

 N. to S. passed over Cape Town on the night of the 2nd of this 

 month (April), the wind chopping very suddenly from S.E. strorg to 

 N.W. fresh. By the foregoing it will be seen how beneficial it would 

 be to know the true state of the atmosphere in this region upon the 

 approach of a cyclone. 



I cannot pass over this portion of my paper without referring to 

 the immense value that would be attached to stations further north, 

 say at Port Nolloth and Walvisch Bay. Of course at the present 

 time telegraphic communication with these stations has not been 

 established, consequently it would be useless to refer to them in any 

 other way than to shew their importance for the future, when per- 

 chance they may be joined to Cape Town by wire. Whenever a 

 depression is advancing from the north, Walvisch Bay will be the 

 first to feel it. An east wind with a falling barometer will be the 

 sign of its approach. If the wind becomes more northerly the de- 

 pression will pass off to the Atlantic, but if it turns to the S.E and S., 

 the cyclone is travelling southwards, and will pass over the Colony. 

 The next stations to watch then are Bloemfontein or Kimberley and 

 Port Nolloth, between which most of the cyclones pass. By carefully 

 noting the changes of wind at these places the path of the storm can 

 easily be followed. 



I do not think I need say anything more in connection with these 

 summer storms ; I hope I have placed enough before you to influence 

 a further investigation, which I sincerely trust to see before long 

 worked out into a practical form, and if through the instrumentality 

 of these few ideas anybody succeeds in advancing practical 

 meteorology in South Africa I shall be satisfied. 



I shall now pass on to what I call the winter cyclones. By 

 referring to the charts for both January and July, it will be seen that 

 a permanent area of low pressure exists to the south of us, but that 

 whereas the positions of the anti-cyclones during January cause the 

 storms formed in this area to have but little effect on the Colony, their 

 positions during July being much further north, exposes the whole 

 Colony to the full force of the South Sea cyclones. Furthermore it 

 will be noticed, on July's chart, that the area of low pressure to the 

 north has entirely disappeared, or travelled so far north that its 

 effects cannot be felt over South Africa, thus it is that though a few 

 of these winter storms make their influence felt during the summer 

 months, during winter they are the only type that ever visit us. 



VOL, IV, M 



