264 Mr. J. Y.\Buchanan [May 8, 



on sharp edges, it seeks out the Hnes 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 description in the ' Archives des Sciences 

 Physiques et Naturelles,' Geneve, 1887, xvii. p. 498. The delinea- 

 tion of the etched ligures by rime was observed by him in the 

 mouth of July in a remote and secluded chamber nearly 250 metres 

 from the entrance of the grotto. In artihcial grottos, like that of the 

 Morteratsch glacier, in which the air circulates freely, the hoar frost 

 disappears very quickly with the end of winter. 



tiun-Weatlierbng of Granular Ice Produces White Surface of 

 Glaaer. — The surface features of glaciers cannot be better studied 

 anywhere than on the Aletsch glacier, which is the largest in Switzer- 

 land, i'rom the Mergelin See up to the Concordia hut, the surface 

 is without danger, and is easily travelled. If the glacier be here 

 crossed, the beiiten truck of the mountaineers is left, and, near the 

 nortn side, the ice, though perfectly smooch and almost level, is quite 

 uu trodden. I otten mude expeditions alone over this part of the 

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

 of dead animais of dilfereut kinds, chieily 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 tne condition of mummies, with their skins drawn tightly 

 over them. The other parent had been lying in a furrow, and had 

 been completely macerated, leaving its skeleton in a broken up 

 condition. I was unable to arrive at a satisfactory solution of 

 how these animals had met their ueath. It was evident, however, 

 that beasts or birds of prey muat be rare, else the remains would not 

 have been so preserved. As a souvenir, I collected a number of the 

 vertebrai of the macerated individual, and took them home. In 

 picking them up, I was much struck with theh resemblance to 

 tue disarticulated grains of a block of glacier ice ; or, rather, it 

 struck me that they were the only objects which I had seen, with 

 which I could compare the grains in respect of their outward form. 

 Just as the vertebrai of the chamois tit exactly to each other, to form 

 the vertebrai column of the animal, so do the grains of the glacier 

 tit exactly into each other to form a compact block. The vertebrae 



