512 PRESENT FUNDAMENTAL CONCEPTIONS OF PHYSICS. 



or slow combustion, a definite amount of beat is generated in tbe fluid 

 by this combustion. But if an equal quantity of zinc is dissolved in 

 tbe diluted sulphuric acid of a galvanic element, which, is closed by an 

 iron wire (wbicb offers considerable resistance to electric conduction,) 

 the amount of beat in tbe galvanic element decreases as compared to 

 that of the same quantity of oxidized zinc, and is manifested instead 

 in the resisting connecting wire, so that this thin wire appears as tbe 

 bearer of a certain amount of beat or of the corresponding kinetic en- 

 ergy. The beat generated throughout the current conductor and aug- 

 mented by the internal work is equal to that wbicb disappears from 

 the galvanic cell wben tbe latter is closed with tbe resisting iron wire. 

 If this experiment is modified so as to put the poles of tbe galvanic 

 battery in metallic connection with copper wires (which latter offer a 

 comparatively small conducting resistance), and if then the ends of 

 these wires are united by a thin iron wire or charcoal points, a great 

 part of the heat of oxidation produced in the battery may be con- 

 veyed to long distances in the form of the electric glow and light. In 

 this process chemical energy is transformed into that of heat, electricity, 

 and again of heat in accordance with the law of the correlation of energy. 



If we analyze water by means of the electric current of a voltaic 

 battery, the quantities of hydrogen and oxygen thereby obtained possess 

 through their chemical attraction (chemical relation or affinity) that 

 potential energy, which disappeared as the kinetic energy of heat from 

 the battery and manifested itself in the closing wire as the kinetic 

 energy of the electric current. Through the electrolysis of the water 

 the electric current must be weakened by the amount required in the 

 work performed in the separation of the atoms of the water molecules. 

 If the mixture of inflammable gas obtained in the electrolysis of the 

 water is set on fire, there arises from tbe explosion, light, heat, and 

 sound; that is three kinds of kinetic energy. If all the losses in these 

 processes could be taken into account, the total of all these energies 

 would be equal to that heat energy which, during the electrolysis, was 

 produced in the battery in the dissolution of tbe zinc. 



In the generation of magnetism in an electro-magnet some of tbe 

 kinetic energy of the electric current is expended, hence a periodical 

 weakening of the current takes place at the moment of the magnetiza- 

 tion; no energy is however required for the retention of tbe previously 

 developed magnetism, because no work is required for the existing state 

 of equilibrium in the electro-magnet, for where no mechanical work is 

 performed no loss of the current can take place. In electro-magnetic 

 motors, where the electro-magnet has to be constantly reproduced, 

 there is then a constantly renewed expenditure of the energy of the 

 electric current taking place. In this case there is an indirect trans- 

 formation of the heat which is produced by the zinc consumed in the 

 battery. This heat is transformed into the electric current, magnetism, 



