360 Prof. BischofF on the Temperaktre of 



The lower extremities of the two Grindelwald glaciers lie respec- 

 tively 1306 and 571 feet lower than LeucTterbad. But warm 

 springs may be met with at a still greater height than Leucker- 

 had. (See Chap. XVII.) 



If we suppose the melting of the glaciers from underneath to 

 be a consequence of the internal heat of the earth, we must also 

 imagine it to be totally independent of the seasons, and that it 

 takes place in winter as well as in summer Saussure,* Escher,-f- 

 Ebel,:j: and others, inform us that the glacier streams flow also 

 in winter; however, the latter observes that they are less copious 

 in that season. 



Although the testimony of such philosophers as these, resi- 

 dent in the Alps, and gifted with such talent for observation, 

 would be sufficient, yet I endeavoured during ray stay in the 

 Alps to obtain information myself upon this subject. All the 

 inhabitants of Grindelwald, of whom I made my inquiries, 

 agreed in assuring me that the lower glacier does not yield a 

 single drop of water in the winter, but that the upper one con- 

 tinues to flow uninterruptedly. Supposing this information to 

 be correct, I thought this difference might be explained by sup- 

 posing that, as the brook which issues from the upper glacier has 

 a temperature 4°.50 higher than that of the lower, its flowing 

 uninterruptedly might be due to springs rising beneath the gla- 

 cier. The chamois hunter I before mentioned, told me that the 

 Data, near LeucTcerbad, which springs out of a glacier hanging 

 down from Bahnhorn, and also the Massa, which issues from 

 the great Aletsch, a glacier extending from 9 to 11 leagues down 

 from the south side of the Jungfrau, and terminating within two 

 leagues of the Rhone, flow throughout the winter. But the up- 

 per Lotsch glacier, as I have already observed, does not yield a 

 drop of water during the winter. In hke manner, Ennemoser 

 was informed that the Pfelderer glacier in Tyrol runs in winter 

 as well as in summer. 



fissures extending to a great depth, and which are particularly frequent in 

 the limestones, are to be found in the Jura, as for instance is proved by the 

 Orbe spring, which is nothing else than the outlet of the lakes in the valley of 

 Joux; which lie 680 feet abo\e it — Voyages dans les Alpes, vol. i. p. 309. 

 Ebel, part iii. p. 221 and 586. 



• Voyages, i. 453. t Gilb. Aiinal. vol. Ixix. p. 123. 



t Ibid. iii. 121. 



