1845.] DE SAUSSURE'S THEORY DEFINED. 97 



or not) is substantially correct. The regular system of 

 crevasses of a glacier is approximately transverse, rather arched 

 upwards towards the origin of the glacier ; and as De Saussure 

 supposes the glacier to be pressed downward by the mass of 

 snow accumulating at its head, it is hard to believe that he 

 could have regarded these fissures as in any way essential to 

 its movement, even were they very numerous ; the tendency 

 of such a pressure from above would rather seem to be to pack 

 the ice like an arch, opposing its convex side to the direction of 

 the pressure. 



The view now given of De Saussure's theory of glacier 

 motion is not only conformable to what may be gathered from 

 his writings, but expresses the unanimous understanding of his 

 numerous commentators, followers, and opponents. As some 

 doubt has lately been hinted as to the definiteness of De Saus- 

 sure's conception of a glacier as a mass devoid of flexibility and 

 plasticity, and urged down a slope as a whole, by the lubricating 

 action of fusion in contact with the soil to an extent which, in 

 extreme cases, might even give it the character of buoyancy, I 

 will take the liberty of quoting some indisputable authorities 

 amongst writers of name in different countries. 



And first from De Saussure himself: 



" La chaleur de la terre fait fondre les neiges et les glaces, 

 meme pendant les froids les plus rigoureux lorsque leur epaisseur 

 est assez grande pour preserver du froid exterieur les fonds 



sur lesquels elles reposent." Voyages, 532 " C'est elle 



qui entretient les torrents, qui, meme pendant les plus grands 

 froids, ne discontinuent jamais de sortir de tous les grands 

 glaciers." 533 



" Presque tous les glaciers reposent sur des fonds inclines ; 

 et tous ceux d'une grandeur un pen considerable ont au-dessous 

 d'eux, meme en hiver, des courans d'eau qui coulent entre la 

 glace et le fond qui la porte. On comprend done que ces 

 masses glacees, entrainee par la pente du fond sur lequel elles 

 reposent, degagees par les eaux de la liaison qu'elles pourraient 

 contracter avec ce meme fond, soulevees meme quelquefois par 



H 



