20 



ELECTROLYSIS. 



The law regulating electro-chemical decomposition can, 

 according to M. Ed. Becquerel, be formulated as follows, facts 

 being generalised : When an electric current passes through two 

 or more binary compounds, the decomposition always occurs in 

 definite proportions, so that, for each equivalent of electricity a 

 chemical equivalent of the substance acting as an acid, or other- 

 wise of the electro-negative constituent, goes to the positive 

 pole, a corresponding quantity of the electro-positive element 

 being deposited at the negative pole. M. Ed. Becquerel has 

 also deduced from his researches the following rule : If one 

 equivalent of a substance, either simple or compound, combines 

 with one or more equivalents of another substance, and the 

 first acts as an acid or electro-negative element in the com- 

 bination, the production of electricity resulting from their 

 chemical action represents the equivalent of electricity. The 

 conclusion is that the quantity of electricity brought into action 

 solely depends on the substance which acts as an acid. 



INFLUENCE OF SOLUTIONS. Faraday's laws are, in practice, 

 verified with such slight discrepancies that these can always 

 be attributed to inaccuracy of calculations, or to experimental 

 errors. M. Soret, who made the study of a large number of 

 solutions, has always found that they were without any in- 

 fluence on the weight of the precipitated metal, as is proved 

 by the few following examples, which are all reduced to the 

 deposition effected by one ampere traversing during one hour a 

 saturated solution of sulphate of copper. 



