LAWS OF MAGNETO-ELECTRICAL HEAT. 63 



of the magneto-electrical machine is governed by the same 

 laws as those which regulate the heat evolved by the voltaic 

 apparatus, and exists also in the same quantity under com- 

 parable circumstances •" 



Having completely settled these preliminary questions 

 he now reverts to the prediction he had made in his 5 th 

 observation, January 24, 1843, viz., " I have little doubt that 

 by interposing an electro-magnetic engine in the circuit of 

 a battery a diminution of the chemical heat evolved per 

 equivalent of chemical change would be the consequence 

 and this in proportion to the mechanical power obtained." 



" For this purpose it was only necessary to introduce 

 a battery into the magneto-electrical circuit, then by turning 

 the wheel in one direction I could oppose the voltaic current, 

 or by turning in the other direction I could increase the 

 intensity of the voltaic by the assistance of the magneto- 

 electricity." " In the former case the apparatus possessed 

 all the properties of the electro-magnetic engine, in the 

 latter it presented the reverse, namely, the expenditure of 

 mechanical power." 



As the result of these experiments he finds that the 

 heat developed is strictly in accordance with the laws he 

 has previously discovered, namely, proportional to the 

 product of the square of the current and the resistance of 

 the circuit, " and is not affected either by the assistance or 

 resistance which the magneto-electricity presents to the 

 voltaic current." That is to say, a definite current in the 

 circuit of the armature (or moving electro-magnet) causes 

 the same heat, whether the armature is at rest or in motion — 

 whether the current is caused (1) by the electromotive force 

 of the battery alone, (2) by the magnetic induction on the 

 moving magnet, (3) or by both of these acting in conjunction 

 or opposition. 



