Primary and Secondary Results of Electrolyzation, 259 



plates or one containing only 5 pairs were used. With acid of 

 this strength, the oxygen evolved at the anode was to the hy- 

 drogen at the cathode, in volume, as 17 is to 64; and there- 

 fore the chlorine would have been 30 volumes, had it not been 

 dissolved by the fluid. 



762. Next, with respect to the quantity of elements evolved. 

 On using the volta-electrometer, it was found that, whether 

 the strongest or the weakest muriatic acid were used, whether 

 chlorine alone or chlorine mingled with oxygen appeared at 

 the anode, still the hydrogen evolved at the cathode was a 

 constant quantity, i. e. exactly the same as the hydrogen which 

 the same quantity of electricity could evolve from water. 



763. This constancy does not decide whether the muriatic 

 acid is electrolyzed or not, although it proves that if so, it 

 must be in definite proportions to the quantity of electricity 

 used. Other considerations may, however, be allowed to de- 

 cide the point. The analogy between chlorine and oxygen, 

 in their relations to hydrogen, is so strong, as to lead almost 

 to the certainty, that, when combined with that element, they 

 would perform similar parts in the process of electro-decom- 

 position. They both unite with it in single proportional 

 or equivalent quantities; and, the number, of proportionals 

 appearing to have an intimate and important relation to the 

 decomposability of a body (697.), those in muriatic acid, as 

 well as in water, are the most favourable, or those, perhaps 

 even necessary to decomposition. In other binary compounds 

 of chlorine also, where nothing equivocal depending on the 

 simultaneous presence of it and oxygen is involved, the chlo- 

 rine is directly eliminated at the anode by the electric current. 

 Such is the case with the chloride of lead (395.), which may 

 be justly compared with protoxide of lead (402.), and stands 

 in the same relation to it as muriatic acid to water. The 

 chlorides of potassium, sodium, barium, &c, are in the same 

 relation to the protoxides of the same metals, and present the 

 same results under the influence of the electric current (402.). 



764. From all the experiments, combined with these con- 

 siderations, I conclude that muriatic acid is decomposed by 

 the direct influence of the electric current, and that the quan- 

 tities evolved are, and therefore the chemical action is, definite 



for a definite quantity of electricity. For though I have not 

 collected and measured the chlorine, in its separate state, at 

 the anode, there can exist no doubt as to its being propor- 

 tional to the hydrogen at the cathode', and the results are 

 therefore sufficient to establish the general law of constant 

 electro-chemical action in the case of muriatic acid. 



765. In the dilute acid (761.), I conclude that a part of the 



2L2 



