Dr Martens on the Glaciers of Spitsbergen. 289 



quid whose temperature at Bell Sound has never been below 

 + 1°.45 C. and whose mean is about + 3°.5. At Magdalena 

 Bay the minimum is +0°.9, the mean + l c .34. As the ice 

 is washed by water at such temperatures, it melts ; however, 

 the glacier continues to descend, supporting itself on the two 

 sides of the bay. So true it is that the glaciers which are 

 at the edge of a rectilinear shore either advance very lit- 

 tle or not at all into the sea. Such were the glaciers of En- 

 tree at Magdalena Bay, and the southern arm of that at the 

 bottom of the bay ; they never went beyond the water-line, 

 and never broke down during our stay. 



If it be asked how it is possible that these immense masses 

 remain thus suspended, I should answer that they rest at the 

 sides and behind on the shore, and that they are held by the 

 upper part of the glacier which sinks deeply into the earth. 

 Besides, when the tide is at the full, the Avater which flows 

 beneath them contributes to their support. When these dif- 

 ferent means prove insufficient, the parts most advanced and 

 separated from the others by crevices fall down ; whence the 

 continual breakings which we have Avitnessed. 



Arches in the Glaciers of Switzerland. — The formation of 

 those vaults or arches of ice, which are admired at the lower 

 extremity of the glaciers of Switzerland, is a phenomenon al- 

 together analogous to that of which I have spoken. These 

 grottos, according to Ebel,* do not exist in winter, but in 

 spring ; the waters produced by the melting of the snow pe- 

 netrate into the crevices of the glacier, then issue by its ex- 

 tremity* and melt sometimes a mass of ice 30 metres in height, 

 by from 15 to 25 in breadth. These vaults remain during 

 the whole summer. The glaciers of Spitzbergen cannot last 

 so long ; in proportion as they advance they sink and are lost 

 in the sea. Hence the immense quantities of floating ice 

 which cover the Icy Sea, and sometimes advance to 45° of la- 

 titude. How can we explain their prodigious number by the 

 simple erosion of glaciers, situate for the most part at the 

 bottom of bays where the sea is calm, and sheltered from the 

 winds and waves of the open ocean % But if we reflect that du- 



* Anleitung die Schwciz zu bcrciscn, t. iii. 1. 120. 



