GLACIERS 307 



corresponding to a particular temperature, humidity, change of 

 temperature, and change of humidity. Every slight lowering of 

 temperature deposits its appropriate form and quantity of ice 

 crystals on every object exposed to these conditions. 



Thus on ice ponds or other masses of ice, at times the crystals 

 are so deposited as to outline the form of the massive crystals in 

 the ice at times so as to show the orientation of the crystals on 

 the surface. 



Probably the most beautiful form of crystal, and certainly 

 the most distinctive one, was to be found in huge masses in all 

 crevasses. Single crystals measured up to 2 inches across, and 

 were built in the form of hollow pyramids. 



GLACIERS 



It is however when in the form of glaciers that one appreci- 

 ates to the full the power of ' the mighty molecule ' : huge val- 

 leys, 5, 10, 20, 30, even 50 miles wide, filled with moving ice, 

 cut by this ice from the solid rock to a depth of thousands of feet; 

 huge streams of ice moving by virtue of their own enormous 

 weight at a rate of 30 feet a year even in the most dormant 

 glaciers. 



Hundreds of glaciers representing every type are to be found 

 along the stretch of shore from Cape Adare to the Beardmore 

 Glacier; some, like the Ferrar and Beardmore glaciers, accom- 

 modating the outflow from the great ice plateau 9000 to n,ooo 

 feet high, others flowing from local neve fields, and others little 

 more than consolidated snow-drifts. 



Owing to the fact that the ' snow-line ' is at sea level, a very 

 large proportion of the glaciers terminate in the sea and dis- 

 charge bergs from their seaward faces as do many Greenland 

 glaciers. More than this, however, the Antarctic glaciers, in- 

 stead of coming to an end where they rest on the sea bottom, 

 often preserve their entities as glaciers or streams of ice while 

 projecting many miles into the open sea. Examples of this type 

 are furnished by ' Glacier Tongue ' between Winter Quarters 

 and Hut Point, and by the Nordenskiold and Drygalski ice 

 tongues farther north. This latter pushes its way into the 

 sea a distance of about thirty miles and has a volume, on a rough 

 calculation, of fifty thousand million cubic yards. 



