Dr Martens on the Glaciers of Spitsbergen. 285 



Kcilhau * are less exclusive. " When the sea is notverydeep," 

 says the English navigator, " the glacier advances to a certain 

 length ; when it is deep and usually covered with ice, as is the 

 case in Baffin's Bay,-f* then the glacier advances very far into 

 the sea, till it reach the bottom of the water at a depth of some 

 hundred feet, and, by breaking into pieces, it produces those 

 mountains of ice which are so often met with to the west of 

 Greenland." A savant, who has not visited the north, but 

 who has attentively studied the glaciers of Switzerland, M. 

 Andre du Luc, has broached a mixed opinion, founded on the 

 data derived from the voyages of Captain Ross. It is to the 

 following effect, as copied literally from his Memoir :% " Im- 

 mense glaciers, formed in the gorges and valleys which open 

 to the sea, are urged forwards, and enter the water to a great 

 depth. For some time, the ice supports itself by its cohesive 

 power ; but when the mass which is without support becomes 

 too great to be maintained by this power alone, it breaks off, 

 and sinks into the sea to four-fifths of its height, and, if the 

 water is sufficiently deep, the mass floats. The glacier con- 

 tinues to advance into the sea, new masses are detached, and 

 thus, in process of time, chains of ice-mountains are formed. 

 If the sea is not of great depth in a bay, the glacier advances, 

 always resting upon, and sliding along, the bottom of the sea ; 

 and it is thus that we witness immense glaciers extending for 

 many miles into the sea, without any portion of their mass se- 

 parating. They have assumed, so to speak, the place of the 

 sea in the bay." 



Leaving for the present the consideration of the glaciers of 

 Baffin's Bay, to which I shall afterwards return, I shall con- 

 tent myself by shewing, — 



1st, That the glaciers situated at the bottom of the Spitz- 

 bergen bays do not terminate at the margin of the sea, but 

 advance into it. 2d, That they never slide along the bottom 

 of the sea, but that th-ey slope towards it, so that the lower 

 face of the glacier is in contact with the surface of the water. 



*L.c.p. 135. t L. c. 1. 1. p. 108. 



t Notice of the Ice in Bj ^ffin's B.iy, Bibliotli. Univ. dc Geneve, t. xiii. Lit- 

 tcrature, p. 208. 1U20. 



VOL. XXX. NO. LX.-.-Al'IlIL 18-11. T 



