LAWS OF MAGNETO-ELECTRIC INDUCTION. 100 



upon arises naturally the consequent inquiry, their 

 cause. 



This has hardly yet been brought into clear view, 

 and therefore here, where our business is to narrate 

 only what has already been accomplished, we have 

 little more to say. Yet we may observe, that what 

 has been called induction exhibits, in a manner 

 which cannot be overlooked, the character of a 

 reaction, and we may almost say, of a mechanical 

 reaction. Mr. Faraday appears to have had this 

 conclusion forced upon him. In his Ninth Series 

 (Dec. 8, 1834,) he argues that magnetism and elec- 

 tricity must be convertible states. " How else," he 

 adds, " can a current of a given intensity and quan- 

 tity be able, by its direct action, to sustain a state, 

 which when allowed to react (at the cessation of 

 the original current,) shall produce a second cur- 

 rent, having an intensity and quantity far greater 

 than the generating one?" It will be recollected 

 that, according to the Amperian theory, electricity 

 and magnetism are identical. If we assume the 

 material reality of the electrical fluid, or any sup- 

 position mechanically equivalent to this, we cannot 

 help having the notion of inertia suggested, by the 

 kind of reaction which a wire exhibits when it suf- 

 fers electrodynamical induction. For by the laws 

 of mechanics, a substance, when put in motion by 

 another substance, produces, at the first instant, an 

 impulse opposite to that of the motion; if the velo- 

 city be uniform, no further effort is perceived till the 



