ATMOSPHERIC ELECTRICITY. 



339 



§ II. — Of the electricity of the clouds. 



When the sky is cloudy without heing overcast the instruments 

 indicate numerous and irreguhxr variations, either in the nature or in 

 the intensity of the electricity. Nearly at the same period, Frank- 

 lin, ''^ in America, and Canton, f in England, first observed that 

 among clouds some were in a positive others in a negative state. This 

 fact was confirmed subsequently by all other observers. Frequently 

 the electric tension was increased in the apparatus when a cloud 

 approached the zenith, and the phenomenon was the more decided 

 w4ien the cloud, after being rapidly formed, was dissipated slowly. 



Science possesses few data relative to the electricity of the clouds. 

 According to observations of De SaussureJ during his sojourn on the 

 Col. de Geant, the electricity of the clouds on the peak of Mount Blanc 

 was found to be constantly positive. Schubler,§ who examined the 

 electricity of the clouds in the region of the air where they are 

 formed, there discovered a force equal to what he was accustomed to 

 find possessed by thick fogs in the low countries, and he obtained 

 no signs of negative electricity except where the rain was formed. 

 We will quote here some of his observations made in an ascent of 

 the Rigi, 5j27G feet above the level of the sea. 



-■■■■ Experiments and Observations on Electricity, pages 112, 114, and 129. 

 t Philos. Trans , vol. XLVIII. 1st part, page 356. 1753. 

 X Voyages dans les Alpes, toni. IV, § 2071, page 282. 

 § Journal de ISchweigger, torn. IX, page 354. 



