258 Dr. Faraday's Experimental Researches in Electricity, 



1797*, and previously by MM. Paets Van Troostwyk and 

 Deiman in 1789 or earlier. That the experiment should never 

 be quoted as proving true electro-chemical decomposition, is 

 sufficiently evident from the circumstance, that the law which 

 regulates the transference and final place of the evolved bodies 

 (278. 309.) has no influence here. The water is decomposed 

 at both poles independently of each other, and the oxygen 

 and hydrogen evolved at the wires are the elements of the 

 water existing the instant before in those places. That the 

 poles, or rather points, have no mutual decomposing depend- 

 ence, may be shown by substituting a wire, or the finger, for 

 one of them, a change which does not at all interfere with the 

 other, though it stops all action at the changed pole. This 

 fact may be observed by turning the machine for some time; 

 for though bubbles will rise from the point left unaltered, in 

 quantity sufficient to cover entirely the wire used for the other 

 communication, if they could be applied to it, yet not a single 

 bubble will appear on that wire. 



329. When electro-chemical decomposition takes place, 

 there is great reason to believe that the quantity of matter de- 

 composed is not proportionate to the intensity, but to the 

 quantity of electricity passed (320.). Of this I shall be able 

 to offer some proofs in a future part of this paper (375. 377.). 

 But in the experiment under consideration, this is not the 

 case. If, with a constant pair of points, the electricity be 

 passed from the machine in sparks, a certain proportion of 

 gas is evolved ; but if the sparks be rendered shorter, less gas 

 is evolved, and if no sparks be passed, there is scarcely a sen- 

 sible portion of gases set free. On substituting solution of 

 sulphate of soda for water, scarcely a sensible quantity of gas 

 could be procured even with powerful sparks, and almost 

 none with the mere current; yet the quantity of electricity in 

 a given time was the same in all these cases. 



330. I do not intend to deny that with such an apparatus 

 common electricity can decompose water in a manner analo- 

 gous to that of the voltaic pile ; I believe at present that it 

 can. But when what I consider the true effect only was ob- 

 tained, the quantity of gas given off was so small that I could 

 not ascertain whether it was, as it ought to be, oxygen at 

 one wire and hydrogen at the other. Of the two streams one 

 seemed more copious than the other, and on turning the ap- 

 paratus round, still the same side in relation to the machine 

 gave the largest stream. On substituting solution of sulphate 

 of soda for pure water (329.), these minute streams were still 



• Nicholson's Journal, 4to, vol. i. pp. 241, 299, 349. 



