434 Miscellaneous Intelligence, 



was not larger than that of a common fountain, but had so well 

 fuzed and pierced the ice, that it now fell through the roof of the 

 vault into the stream below. The cavity formed, which had 

 probably been enlarged by the current of the air, was a little coni- 

 cal at its orifice, and then vertical and cylindrical apparently to the 

 vault. Its diameter at the mouth was perhaps 24 or 30 feet, 

 but a little way down 12 or 15 feet. It was through this that 

 the light had entered the cavern beneath, and the tube of ice 

 which appeared below was probably a ring of ice detached from the 

 bottom of the well. M. Burnand thinks that the crater will go on 

 enlarging, and that gradually the vault, out of which the river issues, 

 will be separated from the glacier, and stand like an enormous arch 

 alone. 



After this he proceeded to a very beautiful natural icy cavern 

 formed in another part of the glacier. The place was perfectly 

 clear, and illuminated by the light which passed through enormous 

 masses of ice ; the ice was of a greenish colour. The place was of 

 extreme beauty, and presented a view at each end over the neigh- 

 bouring country of the most extensive kind. It was concluded that 

 a few weeks of sunshine would destroy the whole. — Bib. Univ. 

 xlii. p. 112. 



24. Meteorological Influence of Terrestrial Electricity. — This 

 subject has been treated of by M. Carlo Matteuci, of Bologna, who 

 endeavours to found certain explanations of natural phenomena 

 upon the supposed accumulation of electricity upon the surface of 

 the earth. He considers that there is accumulation of this power 

 upon particular localities, the electricity itself being developed by 

 evaporation, or other circumstances upon the surface, or by internal 

 chemical action, and when developed, being retained in particular 

 situations by the non-conducting power of the neighbouring earth. 

 This non-conducting power is supposed to depend either upon the 

 particular nature of the ground, or upon its becoming dry by evapo- 

 ration, and therefore, it is said, it is rather upon elevated and isolated 

 places than upon plains, above rocks than over forests, in summer 

 than in winter, and in the middle of the day than during the night, 

 that those stormy clouds are formed which frequently can only be 

 explained by terrestrial electricity. 



One explication furnished by this theory, is considered as in- 

 genious; it applies to those luminous appearances which so fre- 

 quently occur in the atmosphere during the evenings and nights of 

 summer, and are called heat-lightning. These are attributed to 

 electricity produced and accumulated as already mentioned. After 

 sunset, the vapours which condense, form a conducting stratum 

 near the surface, which serves gradually to re-establish the electric 

 equilibrium between the earth and the atmosphere. It is especially 

 in plains, that these flashes are observed, because the electricity 

 accumulated on high and isolated places escapes rapidly in conse- 



