ELECTROLYTIC LAWS. 15 



illustrious savant is also due the knowledge of the' induction 

 currents now in general use in the industrial operations of 

 electroplating. 



ELECTROLYSIS. Faraday has given the name of electrolysis 

 to the process of decomposition by means of the electric 

 current. He termed electrolyte the liquid in which the decom- 

 position occurs ; electrodes, the conductors immersed in the 

 liquid ; anode, the electrode corresponding to the positive pole 

 of the electrical source, and cathode the negative electrode. 

 Faraday has termed ions the substances produced by electrolysis 

 and which are divided into anions and cations, according to 

 their appearing on the anode or the cathode. These three last 

 terms are very little used, but the others are part of the 

 scientific language of every country. 



Two conditions are indispensable in order to produce 

 electrolysis : the substance which is to be decomposed must be 

 a conductor of electricity, and in a liquid state. The said 

 substance is generally dissolved in water ; but water is not 

 absolutely necessary to electrolysis as a few specialists will have 

 it ; chloride of magnesium, for instance, can be electrolysed 

 after it has been brought to a liquid state by means of an 

 igneous fusion; the essential point is to obtain a liquid, no 

 matter the means by which the liquefaction is produced. 



CLAUSIUS' HYPOTHESIS. The real cause of the chemical 

 action of a current is no more known than the initial cause of 

 the current itself; the theory of electrolysis, therefore, is also 

 dependent on mere suppositions. But as, owing to Faraday's 

 discoveries, the laws regulating electro-chemical work are 

 known, the hypotheses, however ingenious they may be, con- 

 cerning the original causes of the said work, are of no more 

 than secondary importance. We will therefore only sum- 

 marily mention the most universally accepted hypothesis, not 

 with a view of confirming the formulaa which will be given 

 hereafter, but in order simply to give to practisers a general 

 explanation of the facts of which they are daily witnesses. 



Clausius admits that matter is constituted of extremely 

 small particles called molecules, which cannot mechanically 

 but can chemically be divided ; the molecules of simple bodies 



