S2 Mr. H. H. HowoRTH on 



contended that while the glacier crystals are very compact, 

 they are bounded by capillary fissures in which water cir- 

 culates freely when the glacier zs at melting temperature^ 

 and he explained that Hugi's results were consistent with 

 this view. They were made with ice at lower temperatures. 

 He urged with Grad that the crystals increase from the 

 water which melts in summer and permeates the glacier, 

 and freezes in winter. He distinguished between his own 

 view and that of Charpentier. The latter, he urged, attributed 

 the movement of the glacier to the dilatation caused by the 

 passage of water into ice in the capillary fissures. According 

 to this alternative theory, the continuous increase in bulk of 

 the glacier is due to the continuous growth of the small 

 crystals which compose it, the growth of the various 

 parts combining in a growth and therefore in a movement of 

 the whole. 



Hagenbach, in order to account for the growth of the cry- 

 stals, instead of postulating an infiltration, urged that the cry- 

 stals absorb each other, and thus grow at each other's expense. 

 In regard to Hagenbach's view, Forel urged that, if true, 

 we ought to find in the "glacier grains" a marked inequality 

 of size, some growing and some diminishing in size, whereas 

 the mass of the glacier is formed of grains of virtually the 

 same size in the same district {Le Grain du Glacier^ 334)- 



M. Hagenbach to some extent concedes this objection as 

 a valid one, but suggests that the infrequency of the 

 occurrence of small crystals may onlymark the surface layers. 



In regard to Forel's view, it involves equal, if not 

 greater, difficulties. In order that crystals of ice may 

 increase in size in the interior of a glacier, its temperature 

 must fall considerably below zero. Forel himself has calcu- 

 lated that if there is to be an annual increase of 0*043 i^ 

 volume, or 0*014 in length, in a glacier crystal, its interior 

 must sink to — 7, a conclusion which is certainly not borne 

 out by the experience we have of the temperature of 



