294 ORGANIC CHEMISTRY 



which have some bearing on this question. We are all familiar with 

 Faraday's law, that, if a current of electricity is passed through 

 a number of cells filled with solutions of different electrolytes and 

 arranged in series, exactly equivalent amounts of the various com- 

 ponents will be liberated at the electrodes in the successive cells. 

 The beautiful experiments of Professor T. W. Richards have demon- 

 strated that we are dealing here with a law which is true for different 

 solvents and over a wide range of temperature ; and also that the law 

 is true with a degree of absolute accuracy which is of the same order 

 as the laws of the combination of elements by weight. We are com- 

 pelled, then, to believe that there is associated with each valence of an 

 ion as it is transported through a solution, or at least as it separates 

 at an electrode, a quantity of electricity which is invariable and 

 independent of the nature of the ion. In other words, we have here 

 a natural electrical unit which can be denned in its relation to atomic 

 weights with a degree of accuracy which seems to be limited only by 

 the refinement of our manipulations. 



It is not always recognized as clearly as it should be that this unit 

 quantity of electricity which is associated with one valence of any 

 ion is not a unit of electrical energy. If it were, the same energy 

 would be required to decompose the equivalent quantity of one 

 electrolyte as of every other, which is manifestly not true. While the 

 same current causes the separation of equivalent quantities in the 

 different cells, the differences of potential, and so the amounts of 

 energy required for the separation, vary greatly. It is evident then 

 that when we say that a unit quantity of electricity is associated 

 with each valence of every ion, we do not use the term quantity in 

 the sense of quantity of electrical energy. Instead of this, when this 

 conception of a unit quantity of electricity is examined, it will be 

 seen that it is a conception of something whose properties are those 

 of matter rather than those of energy. The facts appear to be con- 

 sistent with the idea that the unit quantity of electricity of which 

 we are speaking is of a material nature, and you have doubtless 

 already perceived that I have the theory of electrons in mind. The 

 ingenious experiments of J. J. Thomson have given us considerable 

 reason for thinking that the negative electrons are capable of an in- 

 dependent existence and have also given a probable estimate of their 

 mass, which is small in comparison with the mass of the hydrogen 

 atom. 



It has been customary to think of the unit charge of electricity as 

 being involved only in those reactions which occur in solution. If, 

 however, we accept the theory of electrons, it is evident that the 

 electrons must be present in the molecule of an electrolyte, no matter 

 in what manner it is formed. It is but a step further to the conclusion 

 that the electrons are involved in every combination or separation 



