Dr Martens on the Glaciers of Spitzbergen. 165 



of the slopes often exceeds 30° or 40°, according to Saussure,* 

 and the difference of level between the summit and the base 

 of the glaciers varies from 1590 to 2000 metres. I shall con- 

 tent myself by adducing two examples, which will afford an 

 idea of the extreme limits. When examining Mont Blanc 

 from the height of Cramont, De Saussure t thought he could 

 affirm that its summit was not covered with ice. He reverted 

 to this opinion in his ascent of that mountain and of the Bre- 

 vent ;% thus we may admit that the glaciers which surround 

 Mont Blanc, and, in particular, the glacier of the Bossons, de- 

 scend from its summit, which gives to the latter glacier a ver- 

 tical height of 3795 metres. On the other hand, according to 

 the observations of Hugi, the glacier of Loetsch, in the Valais, 

 is only 1605 metres in vertical height. By measuring that of 

 glaciers which descend from mountains of small elevation, we 

 should certainly find differences of level still less considerable. 



If we seek to discover, as has been done by Hugi, that which 

 exists between the summit and the base of the Mers de Glace 

 (Fime), we find that it is about 940 metres in the Oberland. 

 On the Col du Mont Cervin I have found it to be about 

 1054 metres, on the supposition that the Mer de Glace which 

 covers the Col descends from the little Mont Cervin, for its 

 lower limit is at 519 metres below the culminating point of 

 the Col.§ 



Forms. — The surface of the Spitzbergen glaciers presents 

 none of those sharp points or pyramidal elevations which form 

 the beauty of the inferior glaciers of Switzerland. Their su- 

 perficies is commonly uniform or slightly undulated, like that 

 of the mers de glace in the Oberland and Savoy. It is pro- 

 bable, however, that some of them might be covered with 

 sharp projections, both on account of the great inclination of 

 their sides, || and the occurrence of several unusually warm 

 summers. We know as an ascertained fact that these two 



* L. c. § 524. t L. c. § 914. I L. c. § 1981, note, and § 654. 



§ Height of Little Mount Cervin, called Breithorn by Saussure, 3900 

 metres (§ 2247). Termination of the Mer de Glace on the north, above 

 Zermatt, 2U40 above the sea, according to the barometrical observations of 

 the author. 



|| De Sauseure, l c. § 632. 



