PROFESSOR DANIELL ON THE ELECTROLYSIS OF SECONDARY COMPOUNDS. 221 
Table II. Calculated Results in Equivalents. 
Before the electrolysis the solution contained 
Neutral salt. 
Acid. 
Alkali. 
Free acid. 
96-8 
= 44 
+ 
52 
44 
Zincode after ] 
Electrolysis. 
726 
= 33 
+ 
396 
66 
(-24-2) 
(-11-0) 
(—13-2) 
(+11X2) 
' 
Platinode after 
Electrolysis. 
121-0 
= 55-0 
+ 
66-0 
22 
( -1-24*2) 
(+11-0) 
( + 13-2) 
(—11X2) 
According to this view, the electrolysis of an equivalent of bisulphate of potassa in 
water would yield at the zincode four equivalents of oxygen, one of which would be 
derived from one equivalent of oxisulphion of hydrogen, a second from one equivalent 
of oxisulphion of potassium , and two from two equivalents of water, together with 
two equivalents of sulphuric acid which would remain in solution : and at the plati- 
node, four equivalents of hydrogen, one from the oxisulphion of hydrogen, a second 
from the secondary action of an equivalent of potassium upon the water of the solu- 
tion, and two from the electrolysed water, together with one equivalent of potassa 
in solution. 
I must again guard myself by stating, that I do not think the accuracy of the ex- 
periments sufficient to determine whether the proportions of the electrolytes decom- 
posed are, as I have just represented them, three to one, or four to one ; or whether 
the proportions with regard to water are always the same with respect to them all ; 
but if so, and the results justify the suspicion, the electrolyte, water, must exercise 
a limiting power upon other electrolytes, which is well worthy of further careful in- 
vestigation. The reaction also of other electrolytes upon water, by which its con- 
ducting power is so greatly increased, still remains involved in obscurity. 
The electrolysis of sulphate of copper, under certain circumstances, is attended by 
a remarkable effect, which I think may be explained by the principle just laid down. 
You will remember that in my account of the construction of the constant battery* I 
attributed the precipitation of the copper from the sulphate to “the deoxidating 
power of the nascent hydrogen but from the first I have been generally struck with 
the beautiful crystalline arrangement and close compact structure of the metallic de- 
posit. This is so remarkable, that in the first small sheet of copper which I stripped 
from a platinum electrode, and which is now in my possession, I noticed that the 
scratches of the file, which the latter bore, were perfectly moulded upon it. This is 
unlike what one would have expected, a priori, from the precipitation of a metal, by a 
* Philosophical Transactions, 1836, p. 117. 
