THE WORK OF SNOW AND ICE. 



27.-^ 



are much contorted. This is seen both in section (Figs. 248 and 249) 

 and on the surface (Fig. 250). 



TEMPERATURE, WASTE, AND DRAINAGE. 



The temperature of glacier ice may range downward from the freez- • 

 ing point of water much as other sohd portions of the earth's surface, 

 but it has a fixed upper Hmit at 32° Fahr. (0° C.) because all the heat it 

 receives tending to raise its temperature above that point, is converted 

 into the latent form by the melting of the ice. The range of tempera- 

 ture is greatest at the surface, where it varies from 32° in the summer, 

 to the coldest temperature of the region where the ice occurs. Beneath 



^^^1" 

 ^^^" 



Fig. 248. — Side view of end of glacier. Southeast side of McCormick Bay, North 

 Greenland, Shows structure of ice as well as position of debris. 



the surface the range of temperature is more restricted, and increasingly 

 so with increasing depth. 



