188 HOBBS— ROLE OF GLACIAL ANTICYCLONE [April 24, 



seems to have been early recognized by a number of scientific men, 

 due especially to the writings of the late Sir John Murray, Bernacchi 

 and Buchan. By them it was, however, assumed that this condition 

 was determined in some manner by the earth's southern geographic 

 pole, and was not connected with the inland-ice. A like natural 

 tendency to regard movements within the lower atmosphere as de- 

 termined primarily by their positions relative to parallels of latitude, 

 is more or less general. As an illustration, it is generally assumed 

 upon the basis of few and scattered observations within all save the 

 central European areas, that the ceiling of the troposphore in its 

 descent from the equatorial regions reaches its minimum altitude 

 above the geographic poles, though it is far more probable that in the 

 northern hemisphere at least its minimum of altitude is to be found 

 to the southward above the continental glacier of Greenland. In 

 the southern hemisphere the Antarctic continental glacier is prob- 

 ably centered near the pole, and in consequence conclusions drawn 

 from geographic positions are there relatively indecisive. During 

 the winter season the great deserts of moderate latitudes become 

 likewise the loci of anticyclones. Their influence upon the general 

 circulation within the earth's atmosphere should be, however, rel- 

 ative to that of the inland-ice small by comparison. It is because 

 the inland-ice masses have a domed surface that they permit the 

 air which is cooled by contact to flow outward centrifugally and so 

 develop at an ever accelerating rate a vortex of exceptional strength. 

 As already pointed out in my earlier papers, this is one of the 

 essential conditions for the formation of strong glacial anticyclones. 



Their Strophic Action Believed to be Dependent upon an 



Automatically Recurring Disturbance of Balance 



Between Opposing Forces. 



The Refrigerating Air Engine. — The strophic action of glacial 

 anticyclones is one of their most marked characteristics, and would 

 appear to be dependent upon the shield-like form of the glacier 

 surface. Opposed to each other are here the abstraction of heat 

 from the air above the glacier surface tending to make it slide ofif 

 radially, and the increase of temperature due to resulting conden- 



