Ice and its Natural History 



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disarticulates the ice into its constituent grains, and it splits 

 the individual grain into laminae perpendicular to the prin- 

 cipal axis of the crystal and bounded by the planes of fusion 

 described by Tyndall. These planes are the distinguishing 

 characteristic of the individual ice-grain. 



Under the influence of radiant heat an ice-crystal begins 

 to melt at the contiguous surfaces of these laminae, and the 

 process of disintegration and decay is directed by their plane. 

 On the other hand, an ice-crystal, floating in water and losing 

 heat, generates ice laminae which are directed by the same 



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