SS* Prof. Connel 07i the Voltaic Decomj)ositio7i of Solutions. 



fications of secondary action due to the presence of hydro- 

 carbon. In short, as respects voltaic agency, an alcoholic so- 

 lution may be regarded as an aqueous one, in which a foreign 

 substance is present retarding the principal action, but afford- 

 ing an additional source of secondary agency. 



Accordingly, when the alcoholic solution of an ordinary 

 salt is acted on, the acid and alkali go to their proper 

 poles, as in an aqueous solution, but much more slowly, and 

 the hydrogen of the water of the alcohol is evolved at the 

 negative pole, whilst the oxygen enters into secondary 

 combination. When the base is of easy reduction, metal re- 

 duced by hydrogen appears at the negative ; whatever sub- 

 stance is dissolved, if it is not of a nature to afford room for a 

 secondary action with hydrogen, that element is given off in 

 the same proportion as from water, due regard being had to 

 some circumstances connected with the conducting power of 

 the solution which have been formerly pointed out*. This 

 fact was verified for alcoholic solutions of alkalies, haloid 

 salts, and oxyacid salts. 



It was also found, by experiments similar to those with 

 aqueous solutions of hydracids and haloid salts, that when 

 iodine appears at the positive pole in alcoholic solutions of 

 hydriodic acid or of iodides, it is due to secondary action. 

 Absolute alcohol was charged with dry hydriodic acid gas, and 

 placed in A, fig. 2, (p, 243) and water in B and C, A being 

 made negative, and C positive by seventy pairs of four-inch 

 plates. Effervescence soon arose from both poles, but no disco- 

 loration was anywhere observed, nor acid in B or C until after 

 the lapse of twenty minutes, when a slight brown discoloration 

 from liberated iodine commenced in C with acid reaction. 

 In half an hour the battery was reversed, when the hydriodic 

 solution was instantly discoloured without elastic fluid from 

 the pole in that solution, and with effervescence from the 

 other. This experiment would of course have had more ana- 

 logy to those with water, if B and C had contained alcohol ; 

 but the feeble conducting power of that liquid, and the risk 

 of interfering with the reactions if any substance vvas dissolved 

 in it, prevented its employment. The appearances are, how- 

 ever, best explained on the view that the water of the alcohol 

 only suffers direct decomposition. 



Analogous experiments led to the same view in regard to 

 iodides. 



The appearances with a positive pole of zinc led to the 

 same conclusion. "When a saturated solution of dry iodide 

 of potassium in absolute alcohol was thus acted on by fifty 



* Lond. Edinb. and Diibl. Phil. Mag., Dec. 1841. 



