THE CONSERVATION OF ENERGT 



" Professor Jacobi, of St. Petersburg, had shown that 

 the motion of an electro-magnetic machine generates 

 magneto-electricity in opposition to the voltaic cur- 

 rent of the battery. The author had observed the 

 same phenomenon on arranging his apparatus as an 

 electro-magnetic machine ; but had found that no addi- 

 tional heat was evolved on account of the conflict of 

 forces in the coil of the electro-magnet, and that the 

 heat evolved by the coil remained, as before, propor- 

 tional to the square of the current. Again, by turning 

 the machine contrary to the direction of the attractive 

 forces, so as to increase the intensity of the voltaic cur- 

 rent by the assistance of the magneto-electricity, he 

 found that the evolution of heat was still proportional 

 to the square of the current. The author discovered, 

 therefore, that the heat evolved by the voltaic current 

 is invariably proportional to the square of the current, 

 however the intensity of the current may be varied 

 by magnetic induction. But Dr. Faraday has shown 

 that the chemical effects of the current are simply as 

 its quantity. Therefore he concluded that in the elec- 

 tro-magnetic engine a part of the heat due to the 

 chemical actions of the battery is lost by the circuit, 

 and converted into mechanical power; and that when 

 the electro-magnetic engine is turned contrary to the 

 direction of the attractive forces, a greater quantity 

 of heat is evolved by the circuit than is due to the 

 chemical reactions of the battery, the over-plus quan- 

 tity being produced by the conversion of the mechanical 

 exerted in turning the machine. By a dyna- 

 apparatus attached to his machine, the 

 author has ascertained that, in all the above cases, a 



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