46 DISCUSSIONS IN CLIMATOLOGY. 



would not take place. The heat liberated by freezing 

 is therefore what may be termed low-grade heat — 

 heat incapable of melting snow or ice ; while the heat 

 absorbed while ice or snow is melting is high-grade 

 heat, such as is capable of melting snow and support- 

 ing vegetable growth. Moreover, the low-grade heat 

 liberated in the formation of snow is usually liberated 

 high up in the atmosphere, where it may be carried 

 off by winds to more southern latitudes ; while the 

 heat absorbed in melting the surface of snow and ice 

 is absorbed close to the earth, and is thus prevented 

 from warming the lower atmosphere which is in con- 

 tact with vegetation. The two phenomena, therefore, 

 by no means counterbalance or counteract each other, 

 as it is so constantly and superficially asserted that 

 they do" ("Island Life," p. 140). 



The Fundamental Misconception. — I come now to a 

 misapprehension which more than any other has tended 

 to prevent a proper understanding of the causes which 

 lead to the conservation by snow. Whatever the ec- 

 centricity of the earth's orbit may be, the heat received 

 from the sun during summer is more than sufficient to 

 melt the snow of winter. Consequently, it is assumed 

 no permanent accumulation of snow can take place. 

 This objection, as expressed by Mr. Hill, is as follows : 

 " We have no reason to suppose that at present, in the 

 northern hemisphere, more snow or ice is anywhere 

 formed in winter than is melted in summer. With 

 greater eccentricity, less heat than now would be 

 received in winter, but exactly as much more in 

 summer. More snow would therefore be formed in 

 the one half of the year, but exactly as much more 

 be melted in the other half. The colder winter and 

 the warmer summer would exactly neutralize each 

 other's effects, and on the average of years no accu- 



