286 M. G. Quincke on Electrolysis, and the 



solutions of double cMoride of mercury and potassium into 

 {Cl^Hg + Cr^)2K, or of double iodide of cadmium and potas- 

 sium into (PCd + P) 2K (where the brackets include- the com- 

 plex molecule liberated at the anode), so iodide of cadmium is 

 supposed in a similar manner to be resolved into (PCd + P) Cd, 

 and that the interpretation that cadmium and iodine are both 

 driven to the anode by the electrical current is obviously to be 

 rejected*. 



From the theoretical views here developed this appears to me 

 not at all necessary, and the hypothesis that e and e' are both 

 negative not more speculative than the assumption of such 

 double salts. The only question is whether the conclusions de- 

 rived from that hypothesis are in contradiction to actual facts. 



If I take for an example of those solutions of haloid salts 

 an alcoholic solution of iodide of cadmium, when the partial 

 molecules of the salt are negatively electrical the total molecules 

 of the alcohol, according to equation (21) (§ 55), are positively 

 electrical, and will therefore be conducted to the cathode and 

 thus accelerate the increase of concentration of the solution of 

 iodide of cadmium, so far as it arises from the independent wan- 

 dering of the molecules of iodine and of cadmium to the anode. 

 The same thing occurs when the alcohol itself is decomposed; 

 its partial molecules are separated, whether they are electrified 

 similarly or oppositely. 



From this view of the electrolysis of such a solution of a salt 

 doubts might arise whether the same laws hold for it as for that 

 greater class of electrolytes in which e and e' have different signs. 

 But even then the experiments known to me would contain no- 

 thing opposed to the possibility of this assumption and the theory 

 previously developed (§§ 52 to 55). 



Faraday^s law holds as well for those haloid salts as for the 

 other class of electrolytes, as Hittorf^s numerous and complete 

 researches testify ; he always found that the same galvanic cur- 

 rent liberated equivalent quantities of metal in the silver volta- 

 meter and in the electrolyzed solution of the corresponding 

 haloid salt. 



A second question is whether during electrolysis free electri- 

 city does not appear on the electrodes. I must here remark 

 that even for the other, greater class of electrolytes this question 

 is not yet so completely decided as its importance requires. 



Experiments (§§ 57 to 61) by Kohlrausch and myself have 

 been made on the equal tension of free electricity on the poles 

 of an open battery and of one closed by means of electrolytes. 

 The differences between the two poles are by no means suffici- 

 ently explained; and the thought has often occurred to me 

 • * Pogg. Ann. vol. cvi. p. 645 (1869). 



