248 Prof. Connel on the Voltaic Decomposition of Solutions. 



metallic solution, and in the other in the distilled water, evi- 

 dently was the cause of the difference of the result. The 

 experiment with muriate of zinc and nitrate of silver was 

 varied by placing the solution in a bent tube and pouring 

 distilled water over it, the negative wire being alternately 

 plunged in the water and in the solution. The results be- 

 fore and subsequent to reversal of the battery were the same 

 as in the experiments with asbestus; the only difference being, 

 that in the experiment with zinc solution, a little oxide of 

 zinc appeared to be deposited at the confines between the 

 water and the solution. 



I am aware of the circumstance mentioned by Davy, that 

 the connecting asbestus in an experiment with nitrate of silver 

 acquired a film of silver, water being on the negative side; 

 but without doubting for a moment the accuracy of the state- 

 ment, 1 do not hesitate to conclude, from a consideration of 

 my own results, that the silver had resulted in the single in- 

 stance mentioned from the reduction of silver by the secondary 

 action either of light, or of the hydrogen evolved, by the 

 powerful battery employed, in the negative liquid. 



I thought that a negative pole of tellurium in the metallic 

 solution might, by combining with hydrogen, have prevented 

 the formation of metal at that pole: but 1 found that copper 

 and zinc were deposited even in those circumstances ; showing 

 that nascent hydrogen, v/here the metal held in solution is 

 easily reducible^, rather unites with its oxygen than with the 

 tellurium. 



In regard to haloid salts, I shall afterwards endeavour to 

 show that they are not dissolved by water as such, but as hy- 

 dracid salts. In the mean time I shall mention, that proof of 

 exactly the same description as that which has been detailed 

 in regard to the hydracids, was obtained in regard to solutions 

 of chlorides and iodides of potassium, showing that the chlo- 

 rine and iodine which appear when tiiey are acted on vol- 

 taically has a secondary origin. 



There is also a very simple experiment of a different de- 

 scription which leads to the same conclusion. When an 

 aqueous solution of iodide of potassium was acted on, using 

 a positive pole of zinc, by fifty pairs of two-inch plates, in- 

 stead of iodine separating at that pole, as is the case when one 

 of platinum is employed, there was a speedy and copious de- 

 position of oxide of zinc from the positive pole, with only a 

 bubble or two of elastic fluid, but with brisk effervescence 

 from the negative; appearances which can only be explained 

 on the idea of the secondary origin of the iodine, and are con- 

 formable to the view of the direct decomposition of water, the 



