The Size of the Ice-grain in Glaciers 227 



degree than those of the small ones. Hence it is impossible 

 to furnish an exact statistical account of any block of ice, 

 but the figures in the following tables give a very fair idea of 

 the structural composition of the ice examined. The analyses 

 of blocks E and F are the most complete. 



The first block, A, is from the lower end of the Glacier 

 des Bossons in the Chamonix valley, and it was examined on 

 July 17, 1901, which was one of the hottest days of that very 

 hot week. The other blocks are all from the Aletsch Glacier, 

 as they are found floating in the Mergelin See, the waters of 

 which are retained at one end by the ice of that glacier. The 

 Aletsch Glacier is the largest in Switzerland and it contains 

 the largest ice-grains that I have met with. Different parts 

 of the glacier, even in the immediate vicinity of the lake, are 

 of different grain, and the fragments are easily distinguished 

 as they float in the water. Thus block F is a block of large- 

 grained ice, while E is of comparatively small-grained ice, 

 though it is by no means of the smallest grain. 



List of blocks dissected. 



Block A. Chamonix, July 17, 1901. From the end of 

 the Glacier des Bossons. 



Blocks B, C and D were taken from the Mergelin See on 

 July 21, 1901, and exposed to the sun on a rock for some 

 hours. B and C were then dissected, though not completely; 

 that is, a certain comparatively small portion of each of them 

 remained undissected. D was dissected only in so far as to 

 enable a prominent and very large grain (570 grms.) to be 

 removed and weighed. The remainder was left till the next 

 day. Owing to the high temperature of the air both by 

 night and by day, its size was very much reduced. It is 

 called Block d, and it was dissected on July 22, 1901. 



Block E from the Mergelin See was collected and dis- 

 sected on July 22, 1901. 



Block F had suffered far-reaching sun weathering. It 

 was not removed from the lake but was dissected in the 

 water on July 24, 1901. 



15-2 



