126 M. Oh. Martins' Remarks on M. Durochefs Memoir 



very salient promontory of the left bank, and 7° only on the 

 vertical walls of the right bank. Let him go to the gla(3ier 

 of the lower Grindelwald, at the defile of Stiergeg ; he will 

 find them raised to 45°. Wherever, in short, an obstacle 

 opposes itself to the progress of the glacier, he will see 

 ascending strife engraved by the ice which rises against the 

 rock. This is one of the phenomena which water cannot 

 produce, for it does not engrave rectilinear strise, but hollows 

 out sinuous and ramified canals, holes, and conoidal cavities, 

 giants' kettles, &c. 



The author then adverts to meteorological considerations, 

 for the purpose of shewing that, even in a climate analogous 

 to that of the polar regions, the glaciers of the Alps could 

 not extend to the Jura. To prove this, M. Durocher sup- 

 poses that the mean temperature of these regions is — IS''. This 

 is an error ; the mean of Spitzbergen, according to Scoresby,* 

 is only — 8°; and this statement is confirmed by Franklin, 

 Parry, and the Northern Commission. He affirms, more- 

 over, that the temperature is, during a very short time, above 

 zero. Another mistake, for the means of the summer months, 

 are the following : — 



June + 0° 90 



July +3° 51 



August + 2° 88 



Mean,... 2° 43 



Thus, during three months, the thermometer is habitually 

 above zero. The climate of Spitzbergen is not, therefore, so 

 cold as M. Durocher supposes ; and yet all the valleys on the 

 western coast are filled with glaciers which reach to the 

 sea. If Spitzbergen had the mean temperature of — 15°, 

 there would be no glacier in that island ; for the two condi- 

 tions essential to the formation of glaciers are, 1^/, Abun- 

 dant falls of snow : now we know that these falls are never 

 abundant during severe colds ; 2^, The melting of these 

 snows, which become penetrated with water, and are then 

 converted into glacier. Now, on the grand plateau of Mont 



* Account of the Arctic Regions, vol. i., p. 358. 



