ISO Notice of Prof. Forbes 1 s Travels in the Alps. 



But what is a glacier ? " A snow-clad mountain is not a glacier/' 

 " The common form of a glacier is a river of ice filling a valley, and 

 pouring down its mass into other valleys still lower. It is not a frozen 

 ocean, but a frozen torrent. Its origin or fountain is in the ramifications 

 of the higher valleys and gorges, which descend among the mountains 

 perpetually snow-clad. But what gives to a glacier its most peculiar 

 and characteristic feature, is, that it does not belong exclusively or ne- 

 cessarily to the snowy region already mentioned. The snow disappears 

 from its surface in summer as regularly as from that of the rocks that 

 sustain its mass. It is the prolongation or outlet of the winter-world 

 above ; its gelid masses protruded into the midst of warm and pine-clad 

 slopes and green sward, and sometimes reaching even to the borders of 

 cultivation. The very huts of the peasantry are sometimes invaded by 

 this moving ice, and many persons now living have seen the full ears 

 of corn touching the glacier, or gathered ripe cherries from the tree, 

 with one foot standing on the ice." 



" Thus much, then, is plain — that the existence of the glacier in com- 

 paratively warm and sheltered situations, exposed to every influence 

 which can insure and accelerate its liquefaction, can only be accounted 

 for by supposing that the ice is pressed onwards by some secret spring, 

 — that its daily waste is renewed by its daily descent, — and that the 

 termination of the glacier, which presents a seeming barrier or crystal 

 wall immovable, and having usually the same appearance and position, 

 is, in fact, perpetually changing — a stationary form, of which the sub- 

 stance wastes — a thing permanent in the act of dissolution." The 

 thawing of the ice from the heat of the ground, — the flow of springs be- 

 neath, — the infiltration of rain and snow water from the heat of the sun, 

 and the fusion of the ice by the rain, conspire to produce turbid rivers 

 below the ice, and to excavate enormous arches and caverns. 



Most of the water appears to be derived from the sun and the rain ; 

 and hence the Rhine and other great rivers supplied by Alpine sources, 

 have their greatest floods in July, and not in spring and autumn, as would 

 be the fact if they were fed by rain alone. The swell and roar of the 

 torrents are far greater at noon than at evening, and in the morning are 

 still less remarkable. 



" The lower end of a glacier is usually very steep and inaccessible ; 

 sometimes the glacier falls in an icy cascade a thousand feet — the in- 

 clination being greatest at the beginning and termination, and least in 

 the middle. The glaciers are covered with blocks of stone that have 

 fallen from the cliff's, torn off by the expansion of freezing water, and 

 precipitated by gravity as the sun dissolves the icy bands that held them 

 fast to their native cliffs. As the glacier moves downward, the blocks 

 are borne along in continuous lines on both sides, thus forming the mo- 



