89 



CHAPTER III. 



DISCOVERY OF THE LAWS OF THE MUTUAL ATTRAC- 

 TION AND REPULSION OF VOLTAIC CURRENTS. 

 AMPERE. 



IN order to show the place of voltaic electricity 

 among the mechanico-chemical sciences, we must 

 speak of its mechanical laws as separate from the 

 laws of electro-magnetic action; although, in fact, 

 it was only in consequence of the forces which 

 conducting voltaic wires exert upon magnets, that 

 those forces were detected which they exert upon 

 each other. This latter discovery was made by M. 

 Ampere ; and the extraordinary rapidity and saga- 

 city with which he caught the suggestion of such 

 forces, from the electro-magnetic experiments of 

 M. Oersted, (of which we shall speak in the next 

 chapter,) well entitle him to be considered as a 

 great and independent discoverer. As he truly 

 says 1 , "it by no means followed, that because a 

 conducting wire exerted a force on a magnet, two 

 conducting wires must exert a force on each other ; 

 for two pieces of soft iron, both of which affect 

 a magnet, do not affect each other." But imme- 

 diately on the promulgation of Oersted's experi- 

 ments, in 1820, Ampere leapt forwards to a general 

 theory of the facts, of which theory the mutual 

 ' Thcorlc des Phcitom. Elect rodynamiqnes t p. 113. 



