1877-1878.] sis 



After some remarks, he proceeded as follows : — By " Denuda- 

 tion" we understand the wearing away of rocks, so as to expose 

 others beneath them. The object of this paper is to show how 

 water performs its work as a denuding agent. The idea has been 

 entertained that clouds consist of vesicles of water, and not of 

 spheres. However that may be, two facts must be borne in 

 mind — viz., that small particles of water can float in the air with- 

 out being vesicular ; and that water is capable of forming crystals 

 at great elevations. Snow is not simply a collection of ice par- 

 ticles, when perfectly formed, as it will be in a calm atmosphere, 

 its atoms arrange themselves in beautiful figures. These blossoms 

 form the white caps of our mountains, but here their fragile forms 

 are soon destroyed. The mountain caps are limited by a snow 

 line, below which the snows do not extend in summer. That 

 mountains have not attained an amazing altitude shows that the 

 annual augment or its equivalent must in some way or other be 

 removed from the mountain peaks. True, we have masses de- 

 scending as avalanches, but this is not the only motion of these 

 masses. As each layer of snow is superimposed upon its pre- 

 decessors, the superincumbent mass is sufficient not only to 

 consolidate the lower stratum and gradually cause it to assume 

 the properties of ice, but also to squeeze out the lower stratum. 

 There is also a sliding motion of the entire mass, which when 

 received by a valley undergoes still further solidification, and 

 moves still further down the great slope, scratching and 

 grooving the rocks over which it passes, as well as suffering on its 

 own lower surface; till from melting, the consumption below 

 equals the supply above, when the mass terminates. The portion 

 below the snow-line is called the " glacier," while that above gets 

 the name of "neve," or "feeder of the glacier." From the action 

 of the frost on the cliffs above, blocks of stone fall on the surface 

 of the glacier, which are enabled by the glacier's slow motion to 

 form lines of stones, called "moraines." These stones are de- 



