Alcoholic Solutions. 



355 



pairs of two-inch plates in the bent tube, fig. 3, oxide of zinc 

 soon separated at both poles without 

 any appearance of iodine, or of effer- 

 vescence at the positive. The de- 

 position of oxide at that pole is in 

 conformity with the view of the direct 

 decomposition of water. 



With a similar solution of dry 

 chloride of lithium, oxide of zinc soon 

 separated at the negative pole, with effervescence from that 

 pole, but none from the positive ; and it was somewhat uncer- 

 tain whether any separation of oxide took place at the positive : 

 but little doubt could exist that the oxide originated, as in the 

 case of iodide of potassium, by the action of oxygen of the 

 water of the alcohol on the zinc, and was subsequently dis- 

 solved and transferred to the negative pole. 



The principal condition of the deposition of oxide of zinc 

 at the positive pole, whether in aqueous or alcoholic solutions, 

 appears to be a pretty rapid formation, from brisk action ; 

 and the less powerful the acid, and the less its quantity drawn 

 to the positive side, the more of the oxide separates previous 

 to solution and transference. 



With respect to pyroxylic solutions, I have made few ex- 

 periments ; because if the general rule holds good in regard 

 to alcohol, there can be little doubt that it will embrace pyr- 

 oxylic spirit, since, as I formerly showed, the decomposition of 

 its water is much more readily effected than that of alcohol. 

 I found, experimentally, that when a solution of dry iodide of 

 potassium in rectified pyroxylic spirit was placed in a tube A*, 

 and water in a tube B, the two being connected by asbestus, 

 and A made negative, and B positive by fifty pairs of two- 

 inch plates, although iodine soon appeared in the neighbour- 

 hood of the positive pole in B, yet it was accompanied by acid 

 passing into the water of B ; and after forty minutes' action 

 these appearances continued the same, only more decided, 

 and without any appearance of iodine elsewhere. There is 

 little doubt that the nature of the action was just the same as 

 in aqueous and alcoholic solutions. 



In the whole circumstances, although the evidence may not 

 be of quite so decided a character in some of the cases of al- 

 coholic solutions as in regard to those in water, still I think 

 there need not be much hesitation in laying down as a still 

 more general proposition than that above stated, that '* When 

 solutions of primary combinations of elementary substances, 

 in water and in those liquids, such as alcohol and pyroxylic 

 •Fig. l,(p. 243.) 

 2 A 2 



