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of the pack, but honeycombing may occur in the fast ice near the 

 coastline where wind-blown sand and dust exist. 



Decay of the pack is expedited by mechanical attrition from the 

 swell. The physical erosion of the floes produces scaling, resulting in 

 the formation of a quantity of small blocks and brash. The scaling 

 process enables the sea to reach more extensive areas of ice where the 

 comminution continues. 



The final stages of melting vary with the type of ice. Ice of one 

 winter's growth melts readily in low latitudes, if brine is still present. 

 The internal melting due to variations in the salt content produces a 

 honeycombed appearance with a much greater surface area. Since 

 the rate of heat absorption through conduction is proportional to the 

 area exposed, the rotten ice so formed quickly disappears. Fresher 

 and firmer hummocky ice is longer lived. The old floes are heavily 

 undercut at the water line, but honeycombing is rare, owing to the 

 absence of salt. Underwater rams are produced by the melting back 

 of the uppermost 2 to 3 feet of ice. The years-old hummocks of the 

 Arctic pack, having a homogeneous structure of nearly salt-free ice, 

 and having a minimum of exposed surface in proportion to their bulk, 

 survive the longest in warmer waters. The stons of East Greenland 

 waters consists of ice of this type. 



Break-up on rivers usually occurs 3 or 4 weeks after the mean air 

 temperature has risen above 32° F. Ice on lakes breaks up 2 or 3 

 weeks later, and sea ice may break up about this same time. 



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