MR CONNELL ON THE VOLTAIC DECOMPOSITION OF 



In regard to the latter of these experiments, there can be no doubt that, in 

 saturating the ether with hydriodic acid gas, decomposition took place ; and al- 

 though the nature of this decomposition was not fully investigated, it seems pro- 

 bable that the lower liquid consisted principally of iodised hydriodic acid, result- 

 ing from the combination of^oxygen, derived from the ether, with hydrogen, of a 

 portion of the hydriodic acid ; on which view, water, of course, would be formed, 

 and become the subject of the subsequent voltaic action. During the saturation 

 of ether with muriatic acid, no signs of decomposition were visible ; but still it is 

 not improbable that some internal changes may have taken place, and water re- 

 sulted from the action, united to muriatic acid. Unless such a view be adopted, 

 I should be inclined to hold that there really was direct decomposition of the mu- 

 riatic acid by the voltaic current ; for when I recollect that pure ether resisted 

 very powerful voltaic currents, and that even potash, which has so wonderful an 

 effect in promoting the galvanic decomposition of the water in absolute alcohol, 

 did not make ether more susceptible of electric agency, I cannot allow myself to 

 suppose that the decomposition, in the case of ethereal solutions of the hydracids, 

 is that of water entering into the constitution of ether ; but adhere to the original 

 view, that ether contains no water, and that alcohol consists of ether and of water. 



Under the circumstances, the advisable course evidently is, to omit ether al- 

 together from any general rule as to the voltaic decomposition of solutions, and to 

 limit such rule, as above done, to water, and such solvents as have been ascer- 

 tained to contain water as an essential constituent. 



IV. On the state in which the Haloid Salts are dissolved by Water and Alcohol. 



I formerly endeavoured to shew, by acting on aqueous solutions of haloid salts, 

 both poles being placed beyond the solutions in distilled water, and comparing 

 the results with those obtained by using alcoholic solutions, that the salts exist 

 in the aqueous solutions as hydracid combinations.* The evidence on the subject 

 is, however, quite sufficient, even without any illustration from alcoholic solutions, 

 as the following observations will, I hope, shew. 



It is frequently difficult, particularly in the case of iodides, to observe any 

 acid reaction at the positive pole, when both poles are plunged directly into the 

 solution, on account of the reducing action of oxygen on the acid formed. And 

 even in those cases where acid is observed, that circumstance will not of itself il- 

 lustrate the state of solution ; because it might be held that acid is formed by 

 secondary action at the negative pole, from whence it is drawn to the positive. 

 In this way only on the hypothesis of solution as haloids and direct voltaic de- 

 composition of water only could the separation of reduced metal at the negative 

 be accounted for. A doubt might also exist whether the acid reaction at the pole, in 



* Edin. Trans, xiv. 127. 



