OCEANIC CONTROL OVER CLIMATE 35 



CHAPTER II. CYCLONIC AND ANTICYCLONIC 

 SYSTEMS. 



Another important fact to be considered in 

 regard to the winds, is that they do not blow 

 straight, but mostly in great spiral eddies. The 

 air flows spirally in towards the centre of a 

 cyclone, and outward from an anticyclone. In 

 the southern hemisphere the spiral movement 

 of the air around a cyclonic centre is in the 

 same direction as the hands of a watch ; the 

 air blows round an anticyclone in a direction 

 opposite to that of the hands of a watch. In 

 winter, as the oceanic conditions are cyclonic, 

 the winds of the southern hemisphere will then 

 flow above the ocean spirally, in the same 

 direction as the hands of a watch : whereas, in 

 summer, they move in the opposite direction. 

 There is accordingly a change in the prevalent 

 wind-direction twice a year, causing the equi- 

 noctial gales and unsettled weather of spring 

 and autumn. 



The geographical units of the south tem- 

 perate and tropical zones are six areas of land 

 and water, arranged alternately in a girdle 

 round the southern hemisphere. The units 

 are South America, the South Atlantic, South 

 Africa, the Indian Ocean, Australasia, and the 

 Southern Pacific. During the winter each of 

 the three continents will be a high pressure 

 area, with the wind blowing outward, and 



