262 Ice and its Natural History 



out the lines of separation between the grains and settles on 

 them, showing the whole granular structure. In January 

 1907, there was a wonderful exhibition of this natural dama- 

 scening on the roof of the cave of the Morteratsch glacier ; 

 in January 1908, however, it was quite inferior and would not 

 have struck the eye. The illustration, Fig. 5, represents a 

 portion of the roof of the cave, which I photographed in 

 January 1907. As the roof is not flat, but made up of shell- 

 like cavities, worn by the hot air in summer, the delineation 

 of the grain is sharp in some parts of the photograph and 

 faint in others. 



A precisely similar phenomenon was observed in 1886 

 by Professor Forel, in the remarkable natural grotto of the 

 Arollo glacier, of which he has given so fascinating a de- 

 scription in the Archives des Sciences Physiques et Naturelles, 

 Geneve, 1887, xvii. p. 498. The delineation of the etched 

 figures by rime was observed by him in the month of July 

 in a remote and secluded chamber nearly 250 metres from 

 the entrance of the grotto. In artificial grottos, like that 

 of the Morteratsch glacier, in which the air circulates freely, 

 the hoar-frost disappears very quickly with the end of winter. 



Sun- Weathering of Granular Ice Produces White Surface 

 of Glacier. The surface features of glaciers cannot be better 

 studied anywhere than on the Aletsch glacier, which is the 

 largest in Switzerland. From the Mergelin See up to the 

 Concordia hut, the surface is without danger, and is easily 

 travelled. If the glacier be here crossed, the beaten track 

 of the mountaineers is left, and, near the north side, the ice, 

 though perfectly smooth and almost level, is quite untrodden. 

 I often made expeditions alone over this part of the glacier 

 in the summer of 1895, and frequently met with the remains 

 of dead animals of different kinds, chiefly birds. At one place 

 I fell in with what was evidently a family of chamois which 

 had perished on the ice. There were the two parents and the 

 kid. One of the parents and the kid were lying on a ridge 

 of ice, and, having remained dry, were in the condition of 

 mummies, with their skins drawn tightly over them. The 

 other parent had been lying in a furrow, and had been 



