170 Decomposition of JVafer ly Galvaniim. 



tube tlirough which the elastic fluid passes to form the nni- 

 riate of soda or of potash. We have reduced to a very simple 

 formula the general expression of the results of all the expe- 

 riments of this kind. If, for example, the muriatic acid 

 necessary to neutralise the potash or soda freed from car- 

 bonic acid is a quantity expressed by m, and that the oxy- 

 g-en gas obtained is represented by r;, m -4- n will be the 

 weight of the water decomposed, which we express by P: 

 tlius if the oxygen contained in P equals 0-85/), then the 

 oxygen wh.ch contains m is equal to 0*65 p — n. 



XXIX. On the Decomposition of Water lij Ga.luanisvf^ 

 By John Cuthkertso^-, Esq. 



To Mr. Tilloch. 



PEAR SIR, 



JL HAD, by some means, overlooketl that parajtraph in your 

 valuable Magazine (vol. xxiv. p. 285.) wherein you mention 

 you had been informed that I liad repeated the experiment 

 on the composition of muriatic acid by Galvanism. I did 

 not know you had mentioned it till I was applied to for such 

 an apparatus as you had mentioned. Your information, 

 however, was not perfectly correct : — I performed the expe- 

 riment, but did not intend it for publication till I had re- 

 peated it in a more accurate manner; I only did it to try 

 what would be the consequence when the experiment was 

 performed in such an incorrect manner as any person might 

 be able to repeat. The water which I used was not distilled ; 

 intending, if I found at the termination of the experiment 

 the remaining water to possess any other properties than 

 that which it had before the process, to hold it a sufficient 

 encouragement to undertake an accurate repetition. I found 

 during the process that the gold wire let fall from its surface 

 something that had the appearance of pieces of black rusty 

 metal, and the wire appeared at places much corroded. The 

 plalina wire let fiiU a small white cloud near the end of the 

 process. When one-half of the water had disappeared, the 

 remaining portion, by the usual tests, showed signs of aci- 

 dity. 



