164 Dr Marteus on the Glaciers of Spitzberyen. 



The Germans call them Firne ; we call them Glaciers Superi- 

 eurs, or Mers de Glace. Under the name. of Glaciers Inferieurs 

 (Gletscher), we comprehend the lower part of the glaciers, begin- 

 ning at the inferior limit of the Mers de Glace. Finally, we 

 apply the word glaciers, without addition, to the entire Mers 

 de Glace (Firne) and the inferior glaciers (Gletscher), con- 

 sidered collectively. The glaciers of Spitzbergen being only 

 Mers de Glace, as we shall afterwards see, we apply one or 

 other of these denominations to them indifferently. 



The lower limit of the Mers de Glace of Switzerland has 

 been fixed by Hugi* at 2470 metres. It nearly coincides with 

 the line of perpetual snow ; but it is more constant, for its 

 height is the same on the two declivities of the Alps, and it 

 undergoes no variation in different years. Their upper limit 

 is from 3200 to 3600 metres above the sea, in the group of 

 the Oberland. 



Declivity and perpendicular heiyht. — The inclination of the 

 glaciers of Spitzbergen is very trilling. In fact, the moun- 

 tains on which they rest are not high, and they are, besides, 

 so precipitous, that the glaciers cannot rise above the third of 

 their entire height. From this it follows that the difference 

 of level between the lowest and highest points of these fields 

 of ice is not nearly so considerable as among the Alps. Ac- 

 cording to Scoresby,-f the difference of level between the 

 summit and bottom of the great glacier of Horn Sound is only 

 400 metres. I calculate that of the glacier at the bottom of 

 Magdalena Bay at 350 metres, which reduces its inclination 

 to about 10°. Latta+ estimates that of the Seven Glaciers 

 from 10° to 20° : the principal glacier of Bell Sound was 

 nearly horizontal, owing to its great length. 



The three glaciers of Beerenberg, in the island Jan Mayen 

 (Lat. 70° 49' , are only 390 metres of vertical height above 

 the sea. Scoresby assured himself of this by a trigonometri- 

 cal measurement.! 



In Switzerland and Savoy, on the contrary, the inclination 



* L. c. p. 334 to 337. t L. c. t. i. p. 102. J L. c. p. 95. 



§ Narrative of an Excursion upon the Island of Jan Mayen. (Edin. Phil. 

 Journal, vol. i. p. 121. 1819.) 



