354 Prof. Bischoff' on the Temperature of 



perature of 32°.9, another very small stream shewed SS".?- The 

 brook which flows from the upper glacier, gave a temperature 

 of 33^.3, and that of the Lammern Q'!l°A. As my thermometers 

 shewed exactly 32°.0 upon being plunged into a hole in the 

 melting glacier, it is certain that they were correctly graduated. 



There are three causes to which this elevation of temperature 

 may be ascribed ; firstly, the warm air drawing into the ice-ca- 

 verns from which these glacier-streams issue, may tend to raise 

 the temperature of their waters. This may be the case espe- 

 cially in the lower Giindelwald glacier; in a less degree in the up- 

 per Grindelwald and Lammern glaciers, because in neither of 

 them does the water issue from caverns in the ice, but flows im- 

 mediately from under the ice,: secondly, the heat of the earth 

 may assist in warming them ; and thirdly, springs and streams 

 of water, coming down from the mountains between which the 

 glacier is enclosed, and flowing underneath the glacier, may also 

 assist in raising their temperature. This seems indeed to be 

 the case with the upper Gr'mdehvald glacier, and may account 

 for the high temperature of 33°.3 of the Schwartze Lutschine ; 

 namely, from the Wettcrhorn there descends a considerable 

 brook, the Weisbach — and from the Mettenberg a still larger 

 one, called the Milchbach, both of which penetrate into the gla- 

 cier, the one on the east, the other on the western side. Although 

 these streams are nothing else than glacier-streams, proceeding 

 from the upper parts of the glacier, yet during their course 

 above ground they will acquire, in the warm seasons, a higher 

 temperature, which thev will afterwards communicate to the 

 other waters with which they unite beneath the glacier. That 

 there are currents of air between the descending stream of wa- 

 ter and the ice, notwithstanding that there is no cavern in this 

 glacier, is proved by the well-known adventure of the inn-keep- 

 er of Grindelwald, Christian Boren, who fell into a crack 354/ 

 feet deep in this glacier, crawled up 396 paces on his belly in 

 the bed of the Weisbach, which he was three and a half hours 

 in accomplishing, and came out on the Wetter-horn, where the 

 Weisbach enters the glacier, having sustained no further injury 

 than a broken arm. His son told me that his coat buttons were 

 all rubbed off except the two top ones. 



The canal was therefore very narrow, but yet, of course, fill- 

 ed with air. 



