THE PATH OF EVOLUTION 



tion of metallic salts, copper or silver salts for instance, 

 the salt will be decomposed and the metal deposited 

 upon the surface of the object attached to the Kathode 

 or negative pole, plate, or wire corresponding to the 

 Zinc elements of the battery a copper plate, if a 

 copper or silver salt be used, constituting the anode, 

 the opposite or positive pole. Thus also the chemical 

 action between the metal and acid may be used for 

 producing light or heat by the electric current, or it 

 may be used for causing magnetic attraction between 

 the poles of the electro-magnet and its armature in 

 a Dynamo, thus giving rise to mechanical motion. 

 Mechanical motion again in its turn, when applied to 

 a dynamo, generates magneto-electric currents that 

 will produce chemical combinations or decompositions, 

 heat, light, and all the other phenomena above-named. 

 The phenomena of Magnetism undoubtedly one 

 of the forms of Electricity and of the ethereal medium 

 are yet very imperfectly understood. The natural 

 Magnet, the Lodestone, early attracted attention. 

 Plato thus speaks of it : "A divine power, which 

 moves you, like that in the stone which Euripides 

 calls the Magnesian, but the common people Hera- 

 clean. For this stone not only attracts iron rings, 

 but it imparts a power to the rings, so that they are 

 able to do the very same things that the stone does, and 

 to attract other rings and sometimes a very long series 



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