I9IS.] IN AIR CIRCULATION OF THE GLOBE. 221 



groups it would now appear that the stationary " lows " are located 

 where land barriers oppose a progressive movement. 



The Role of the Glacial Anticyclones of High Latitudes in 

 THE General Air Circulation. 



Circulation is Through Cyclones and Anticyclones, Not Merely 

 Within Them. — In an earlier section it has been shown how the 

 preconceived notion of a polar cyclone, the circumpolar whirl, has 

 held back the advance of knowledge where the polar regions are 

 concerned ; and how this theory has now been effectually disposed 

 of by the observations of de Quervain, Stolberg, Barkow and others. 



The progressing cyclones within the atmosphere were by Ferrel 

 assumed to be symmetrical in their distribution, with warm upward- 

 moving central portions and cold marginal rims ; to circulate the 

 same body of air which repeatedly passes through certain paths ; 

 and to have their origin in areas of excessive local insolation. 

 Instead of being symmetrical, as has now so generally been as- 

 sumed, the study of isotherms in connection with cyclones has 

 shown that these lines usually trend in the United States from 

 southwest to northeast, crossing the cyclone by quite regular paths 

 instead of being circular about its center. The evidence derived 

 from international cloud observations would seem to show that the 

 cyclone is a form of circulation through which fresh portions of 

 the atmosphere continue to stream; and both cyclones and anti- 

 cyclones are to be regarded as eddies which at the surface of the 

 earth have each a hot and a cold side. The same air streams 

 through both, its progress when projected upon the earth's surface 

 being a sinuous line. 



Belts of Progressing Cyclones and Anticyclones about the Ant- 

 arctic Glacial Anticyclones. — The southern hemisphere, being less 

 invaded by the continents, offers for the purposes of study some 

 advantages on the side of relative simplicity, and it has in its 

 meteorological aspects been recently comprehensively treated by 

 Lockyer,'^^ who has taken full account of the results of Antarctic 



^® W. J. S. Lockyer, " Southern Hemisphere Surface Air Circulation," 

 etc., Solar Physics Committee under direction of Sir Norman Lockyer, 

 London, IQIO, pp. 109, pis. 15. jf 



