132 MR CONNELL ON THE ACTION OF VOLTAIC ELECTRICITY 



tint confined to the positive side of the surface. The liquids in C and D were 

 then concentrated by heat, when the former was found to contain a trace of hy- 

 driodic acid, whilst the latter contained a trace of iodic acid. Hydriodic acid 

 had thus been drawn, first, into C, and then into D, where it was decomposed by 

 nascent oxygen, and a part of the liberated iodine oxidated. 



A comparison was next instituted between alcohoMc and aqueous solutions 

 of the chlorides of calcium and of zinc. 



Absolute alcohol containing I'sth of recently ignited chloride of calcium was 

 placed in B, Fig. 3, and water in A and C, A being made positive and B negative 

 by a power of 72 pair of 4-inch plates. In a quarter of an hour acid was de- 

 tected at the positive pole, and on the adjoining asbestus, immediately above the 

 surface of the liquid in C, but not a trace of it in B. In half an hour there was 

 still no trace of acid in the liquid in B, but there was a trace of it on the asbes- 

 tus at the positive side of B, having evidently spread from the other side of the 

 same asbestus, where it was before observed, and where as well as at the posi- 

 tive pole it was now strong. In three quarters of an hour there was a just per- 

 ceptible trace of acid in the liquid in B on the positive side, and strong acid all 

 along the asbestus to the positive pole. This very trifling trace of acid in B had 

 thus evidently spread from the asbestus, as just mentioned, and had not lieen 

 produced in B. An alcaline reaction was observed at the negative pole. No smell 

 of chlorine or bleaching action was any where noticed. When the experiment 

 was concluded, the hquid in C was found to be a weak solution of muriatic acid, 

 with a just perceptible trace of the smell of chlorine ; this acid being too strong 

 a combination to be so readily decomposed by nascent oxygen as hydriodic acid. 



When a moderately strong aqueous solution of chloride of calcium was sub- 

 stituted in B for the alcoholic solution, and a power of fifty pairs of 2-inch plates 

 employed, there was decided acid on the positive side of B in less than twenty 

 minutes, with a slight trace at the positive pole, and none on the intermediate asr 

 bestus. In half an hour the acid in B was powerful, whilst there were still 

 merely traces at the positive pole and on the asbestus, with alcaline reaction at 

 the negative pole. No trace of chlorine was observed, although the action w^as 

 continued above two hom-s. 



With a pretty strong solution of recently ignited chloride of zinc in absolute 

 alcohol in B, and water in A and Q, the same voltaic power being employed as in 

 2ast experiment, there was no acid reaction in B after forty minutes' action, whilst 

 a trace of acid had appeared at an early period on the asbestus above the surface 

 of the positive liquid in C. On the other hand, when an aqueous solution of chlo- 

 ride of zinc was substituted in B for the alcohoMc, all other circumstances being 

 the same, there was strong acid in B in ten minutes, with none at the positive 

 pole, and only a trace on the intermediate asbestus. In neither experiment was 



