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PAET II. 



ELECTROSTATICS, ELECTROKINETICS AND MAGNETISM. 



CHAPTER VI. 



ELECTRICAL PHENOMENA. SYSTEMS OF CONDUCTORS. 



128. Fundamental Experiments. We shall begin the 

 treatment of Electricity by the description of a number of simple 

 experiments, for the most part due to Faraday and described by 

 Maxwell, the explanation of which will devolve upon the theory, 

 when mathematically established. 



EXPERIMENT I. Let a piece of glass and a piece of resin, 

 neither of which exhibits properties different from those of 

 ordinary bodies, be hung up near each other by silk threads. 

 They do not affect each other, and the threads hang vertically. 

 Let the glass and the resin be rubbed together, and left in contact. 

 They still exhibit no peculiar properties. Let them now be 

 separated. They attract each other, and the strings take an 

 inclined position. The system composed of the glass and resin 

 has now acquired energy, which has enabled it to do work against 

 the force of gravity in lifting the two bodies through a certain 

 distance. 



Let a second piece of glass be rubbed with a second piece of 

 resin, and be similarly suspended. Then it may be observed that 

 the two pieces of glass repel each other, and have therefore 

 acquired energy, which is evinced by their overcoming gravity in 

 lifting themselves. 



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