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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



[vol. 47 



cular in cross-section and, judging- from the way water passes along 

 them, quite free from air. Their walls reflect the light strongly and 

 give the appearance of a network of silver threads, more or less per- 

 fectly outlining the granules. From beneath the ice it was possible 

 to get limited areas of them upon a photographic plate and these 

 are reproduced in fig. 86. By using a strong solution of potassium 

 permanganate it was found that they could be beautifully injected, 

 the solution entering the ice in a few minutes to a depth of several 

 feet. Such injected capillaries from the Illecillewaet glacier are 



Fig. 87. — (llacier capillaries, injected. Illecillewaet. 



shown in rig. $j. Upon the faces of crevasse walls and ice caves 

 these tubes are frequently seen in longitudinal section, forming a 

 pattern by which the granules are outlined. As melting proceeds, 

 within the ice, the capillaries become irregular and crinkly, spaces 

 are opened up between the adjoining faces of neighboring granules, 

 and the original network becomes obliterated. With tins increased 

 reflecting surface the beautiful blue color of the ice gives way to 

 white and in places causes it to again resemble the neve. A small 

 amount of pressure now, or a blow, will cause the ice to crumble into 



