The Yawning Crcvasises. 31 



glacier varies much with the locahty. From an elevated point 

 such as V, from which the minor irregularities are not j^i'omi- 

 nent, the general smoothness seems broken over limited areas, 

 like the surface of a still lake ruffled in places by puffs of wind. 

 These are, of course, where the bed of the glacier presents some 

 irregularity. Below them the sides of the crevasses are again 

 pressed together, and the surface resumes its general smoothness. 

 The increase in the width of crevasses during the summer was 

 very noticeable. In the beginning of September Ave were unable 

 to cross the northwestern tributary, although earlier in the season 

 Professor Muir crossed it without much difficulty. 



The place where the crevasses were most marked was the im- 

 mediate neighborhood of the glacier's mouth. Here two sets of 

 crevasses cutting each other obliquely divided the ice into great 

 lozenge-shaped masses, which, under the influence of the sun, 

 rain and winds, melted, in some cases into narrow^ ridges, in others 

 into sharp pinnacles. The ice, white near the surface, becomes 

 bluer and bluer as one looks deeper into a crevasse, which finally 

 ends in a dark narrow crack. This gives the impression of im- 

 mense depth, but I do not believe that any of these crevasses are 

 much over 150 feet deep. We sounded one and found it 128 

 feet. The best evidence, however, lies in the sections of the 

 crevasses shown in the photograph of the ice-front from which 

 plate 13 is reproduced, in which the crevasses do not extend to 

 the water level, which in this part of the ice-fi'ont is less than 200 

 feet below the surface of the ice. The ribbon structure of Forbes 

 was everywhere visible. On many of the jDinnacles it could be 

 seen cutting the stratification at a high angle. 



Melting and Drainage. 



The stakes put in the ice to measure the motion of the eastern 

 part rose about 14 inches in 7 days, which indicates a melting 

 of about 2 inches a day. This method is not reliable, and we 

 can consider the result as only approximate. In this particular 

 portion of the glacier the ice is very friable, and the water does 

 not collect on the surface in pools and streams, but sinks through 

 the ice and is carried off by some crevasse. The portions just 

 west of G and between White glacier and I contain many sur- 

 face streams which pour into crevasses or moulins ; but none of 

 these streams were two large to leap, and all of them were per- 

 fectly clear. 



