CAUSE OF MAGNETIC POWER. 449 



and some others, blue light; arid iodine, violet 

 light, but that when different elements are 

 burnt together, the result is a compound light, 

 which may be decomposed with a prism into 

 different primitive colours like the solar rays 



in short, that there is no essential difference 

 between electric light and that of ordinary com- 

 bustion, and that electricity is never luminous 

 or visible, except when in a state of combina- 

 tion with ponderable matter, as maintained by 

 Fusinieri. 



Since the discovery of OErsted, that a metallic 

 wire which connects the extremities of a voltaic 

 battery in action, is capable of deflecting a mag- 

 netic needle placed near it from its ordinary 

 position ; and of Davy and Arago, that it is 

 capable of attracting iron filings during the pas- 

 sage of an electric current through it, philoso- 

 phers have seemed to suppose that the produc- 

 tion of magnetic effects was a peculiar and dis- 

 tinctive attribute of electricity. But if it were 

 established, that electricity is a distinct fluid, sui 

 generis, it is nevertheless demonstrable, that ca- 

 loric is capable of producing magnetic pheno- 

 mena in a still more remarkable and universal 

 manner and that electricity of high* tension, 

 which produces a shock, and darts through 

 metals with the greatest velocity, produces very 

 feeble and partial effects on the magnetic needle, 

 during its passage through a multiplying wire. 



G G 



