Dr Martens on the Glaciers of Spitzbtrgen. 175 



consider them as central moraines, or as moveable blocks trans- 

 ported transversely from the sides towards the centre of the 

 glacier, is of little importance, for it is easy to prove that these 

 blocks could not be moved in this manner on the glaciers of 

 Spitzbergen. To those who regard the blocks placed in the 

 middle of glaciers as centijal moraines, I would say that the 

 mers de glace of Spitzbergen are rarely formed by the union 

 of many small converging glaciers. Placed in the bottom of 

 bays, they rest on an amphitheatre of mountains completely 

 hemmed in ; consequently they never could have central mo- 

 raines. However, the glacier at the bottom of Magdalena 

 Bay is formed by the union of five small secondary glaciers ; 

 but these are very short, and the summits which overlook them 

 of inconsiderable elevation. Hence it is that very few stones 

 fall on these upper glaciers ; below, on the contrary, the moun- 

 tain is disengaged from the glacier, and every block which 

 rolls down its sides falls upon the ice. 



Those who favour the explanation given by Saussure will 

 likewise find arguments in the phenomena of Spitzbergen gla- 

 ciers. In truth, as the latter do not melt at the lower surface, 

 as I shall attempt to prove, it follows that they do not become 

 excavated beneath, and that the principal cause of the sinking 

 of which Saussure speaks does not exist ; consequently the 

 blocks cannot thus be transported perpendicularly to the axis 

 of the glacier. Let it not be forgotton that the lowest point 

 of these mers de glace corresponds to the line which separates 

 the upper from the lower glaciers of Switzerland. Now, it is 

 exactly at this level that the blocks begin to show themselves 

 on the surface of the Alpine glaciers ;* for example, at the 

 upper part of the lower glacier improperly called Mer de GUiee 

 at Chamouni. In Spitzbergen it is at the edge of the Mer, 

 lower down than the point where they have been sunk in the 

 earth, but at the same distance from the axis of the glacier, 

 that is to say, on its lateral parts, that the blocks begin to rise 

 to the surface. 



In short, the existence of blocks on the sides, and their ab- 

 sence in central parts, arc tw<> unquestionable facts. It thence 



■ Hugi, L c. p. :»'»:{. 



