HIMALAYAN SNOWS. 425 



further ridges of this great mountain chain, which lie 

 still further to the north. 



On these matters however we fear, as we have said, 

 that sufficient data do not exist to enable any positive 

 opinion to be formed. We therefore venture to tender 

 our own views upon them as a hypothesis only. 



But whatever may be the operation of the law of 

 Nature in these respects, it is certain that upon the 

 Himalayas, as well as on all other great mountain 

 ranges, vast quantities of water are condensed. In 

 the higher regions above 16,000 or 18,000 feet over 

 sea level it is probable that nearly the whole of 

 this is deposited as snow. Here therefore, we have a 

 constant and never failing supply of stored up water 

 for the torrents, which the sun's action causes to pour 

 down their sides. The description of the formation of 

 rivers by these means, more properly belongs to our 

 next section, " The Region of the Great River Basins, " 

 so that we shall confine our remarks at present to 

 the consideration of their sources, as torrents only, 

 with regard to the question of the " denudation " of 

 mountains by their action. 



Taken in its largest sense, the phenomenon of 

 denudation involves such mighty issues, as regards 

 the future of our earth, and raises such a complex 

 array of scientific questions, that the human mind 

 might well hesitate in approaching so great a subject ; 

 we purpose however, at present, merely to venture 

 upon a short survey of its action upon mountains. 



If a child should ask us, What age are the hills? 

 even the most uneducated person would say They 

 are old: very old. If the enquiry was pushed a step 

 further, by the rejoinder of, How do you know? we 



