Dr Martens on the Glaciers of Spitsbergen. 295 



side ; the intervals which separate each of the compartments 

 are the crevices; and the compartments represent the wedge- 

 shaped masses of ice, of which a certain number are every 

 year swallowed np by the sea. Is it necessary for me to add, 

 that this comparison is not rigorously exact, but that its only 

 object is to illustrate my idea 1 It is very evident, for example, 

 that the wedge-shaped masses would, in the end, totally sepa- 

 rate when the crevices are filled and covered with snow, which 

 at a later period must be converted into solid ice. 



Another analogy, and the last we shall allude to, exists be- 

 tween the glaciers of Spitzbergen and those of Switzerland. 

 The latter, in consequence of their annual melting, send to 

 the sea great rivers which maintain the uniformity of its level. 

 The glaciers of Spitzbergen contribute to the same result by 

 periodically throwing into it immense masses of floating ice, 

 which lower the temperature of the northern seas, diminish 

 their evaporation, and render rains rare and scanty in regions 

 situate to the north of the polar circle. If in these countries, 

 now covered with marshes which the sun is unable to dry up, 

 notwithstanding his long presence above the horiz-n, rains 

 were as frequent as in temperate zones, the line of perpetual 

 snow would become still lower, the marshes would continually 

 increase in extent, and these regions, already so little fa- 

 voured by nature, would become altogether uninhabitable. 



Additional Note. 



Men of science, as well as men of the world, have long been 

 desirous to ascertain whether the glaciers of Switzerland are 

 continually advancing into the plains, or whether they are now 

 in the same place they occupied many ages ago. In Norway, 

 also, a few documents havejbeen collected on this subject. As 

 the progress of glaciers prevents cultivation in lands formerly 

 subjected to it, it is more easy to find proofs of their advance 

 than recollections of their decrease. Acts and contracts 

 establish the existence of a house, a field, or a forest ; but 

 what interest could the inhabitants have in measuring the 

 extent of a surface covered with blocks and sand, and doomed 

 to eternal sterility ? 



In regard to Spitzbergen, the data are still more uncertain ; 



