346 M. Esclier dc la Linth on certain Phenomena 



centimetres. The figures merely give an idea of the form 

 of the curves. 



Starting with the supposition that ice is rigid, M. Durocher 

 says that the glacier can exercise its grooving power only at its 

 bottom. Fig. 5, Plate III., representing the end of the western 

 arm of the glacier of Viesch, and its western wall overhanging 

 and furrowed, shews, in my opinion, with all the evidence de- 

 sirable, that the assertion alluded to is not correct. In fact, we 

 there see, from a height of nearly 2 metres above the ground, 

 the glacier resting immediately upon and against the granitic 

 wall, whose rounded and polished surface exhibits large fur- 

 rows a little inclined towards the horizon, and which extend 

 to a distance in a direction parallel to that of the glacier. 

 In the concave and convex parts of the granitic surface we 

 see, moreover, smaller and shallower furrows, from 2 to 5 

 centimetres broad, sensibly parallel to the great furrows ; 

 besides, we remark, principally in the furrows, a multitude 

 of extremely fine, scarcely visible, striae, parallel to the fur- 

 rows. Stones* were set in the ice, so firmly cemented with 

 it (evidently by the pressure of the superior mass of the gla- 

 cier, which rose 100 feet above the ground), that I had much 

 difficulty to detach some of them with a hammer. These 

 stones, a little rubbed on the side of the rock, were covered 

 on the same side by an extremely fine mud, almost unctuous 

 to the touch, owing to the fineness of its grain. This mud, 

 mingled with fine sand, likewise covered the accessible part of 

 the overhanging rock, separated from the glacier at the base 

 by an empty space, evidently produced by the influence of the 

 summer heat. This cavern continued to get narrower up 

 the glacier in such a manner that it was scarcely 20 paces 

 long. Some weeks earlier, one would, no doubt, have seen 

 the glacier skirting the rock to the base ; but then one could 

 not have seen the large furrows extending beneath the gla- 

 cier, as was then the case.t 



* These stones had, no doubt, originally fallen from the higher parts of the 

 wall, or the surface of the glacier, in the interval which, on the surface of 

 glaciers, is so often found between the ice and the walls of its bed ; they were 

 then enclosed by the ice. 



t There is considerable obscurity in this page, owing, probably, to a bad 

 manuscript. 



