The next important step in the fundamental under- 

 standing of matter was the demonstration that all atoms 

 contain electricity, and in fact are essentially electrical 

 in nature. That electricity could be obtained from matter 

 in various ways, including by means of certain chemical 

 reactions, had been known for some time when Faraday 

 (1830) performed a series of experiments which showed 

 that electricity was also composed of discrete "atoms of 

 electricity" — now known as electrons. Faraday investi- 

 gated the manner in which electricity was able to pass 

 through solutions of metal salts in water, the process of 

 electrolysis. He discovered the following facts regarding 

 this process: (1) The weight of a chemical element which 

 was set free from combination with another element in 

 a salt during electrolysis, was proportional to the total 

 quantity of electricity which had been passed through the 

 solution; and, (2) when the same quantity of electricity 

 was passed through the solutions of several different salts 

 successively, the weights of the various elements set free 

 in each case were proportional to the relative weights 

 in which these elements combined in chemical reactions. 

 Faraday saw that the first of these two Laws of Electrol- 

 ysis was explained if the liberation of each atom of an 

 element corresponded to the transfer through the solution 

 of one, two, or some small, fixed, number of electrons, any 

 given quantity of electricity thus containing a definite num- 

 ber of electrons. The second law was explained by the as- 

 sumption of the existence of electrons, together with the 

 known facts of the relative combining weights of different 

 elements, since if for example the setting free of one atom of 

 any element from combination required the passage of one 

 electron, then evidently the weights of different elements lib- 

 erated by a definite number of electrons must be proportion- 



51 



