POLAR INFLUENCES ON WORLD WEATHER 37 



world. It is essentially a world problem, and before it can be clearly 

 understood a network of stations must cover the oceans and the polar 

 regions as well as the extra-polar land surfaces. The contrasts between 

 pole and equator and between land and water acted on by an ever- 

 changing intensity of solar radiation are the chief factors the play of 

 which must be studied with the aid of physics and mathematics. 



