Conversion of Neve into Ice, 149 



annual layers of the Neve are seen. But tliese wholly dis- 

 appear farther down ; the great body of the ice in the hollow 

 of the basin exhibits little sign of structure ; only near the 

 lateral and medial moraines the structure is icy and vertically 

 veined, elsewhere it is decidedly snowy, with hardly any trace 

 of bands either vertical or horizontal. This is true even as 

 far down as the line of stations W in the figure. The gene- 

 ral disposition of the structural lines, where they exist 

 (which, it is to be recollected, are almost vertical), is seen in 

 the same figure perpendicular to the crevasses. From these 

 facts I conclude, first, That the vertical structure is too 

 close to the original strata of the Neve to allow of the suppo- 

 sition that these have all of a sudden turned up vertically in 

 some parts of the glacier, and disappeared in the remainder. 

 2dly, That where the vertical bands are not developed in the 

 higher glacier, the structure remains snowy and undefined. 

 Zdli/^ That the conversion into ice is simultaneous, and in this 

 case identical with the formation of the blue bands. Athly^ 

 That these bands are formed where the pressure is most in- 

 tense, and where the differential motion of the parts is a 

 maximum, that is, near the walls of the glacier ; but being 

 once formed, it still continues, at least for a time, to be ob- 

 served under the medial moraine, and this may even be traced 

 throughout the ice -fall of the Talefre. 



I am satisfied then (and it is only after long doubt that I 

 venture this confident expression), that the conversion of 

 snow into ice is due to the eff^ects of pressure upon the loose 

 and porous structure of the former ; that the very first effect 

 is to annihilate the annual strata of the Neve, and that the 

 most rapid glacification is effected by the kneading or work- 

 ing of the parts upon one another, by the differential motions 

 which the semi-fluid law of glacier progression occasions, 

 and which also necessarily takes place under intense pres- 

 sure. 



The belief which I formerly (in common, probably, with 

 most other persons) entertained, that snow could not pass 

 into pellucid ice without being first melted and then frozen, 

 was part of the chemical prejudice that molecular actions 

 cannot take place except in the liquid state, a prejudice now 



