eT Ts 
ON ELECTROLYSIS. Gali 
the actual speed of moving salt atoms and the water atoms are neglected. 
Kohlrausch’s numbers are in fact totally different things from our a, y, 
a’, y', which include along with the idea of velocity the idea of amount of 
substance available for conducting the current. In terms of a notation 
to be used later, = pep pred (8 wy 
a’ Py" Ng te 
Generalisation of the above, to suit the case when a mixture of ions may be 
> y 
gwen off at each electrode. 
If we now extend our view a little to cover cases (1), (2), and (3) at the 
same time——that is, to take account of a possible mixture of liberated ions, 
such as one frequently gets with intense currents, and may get at any time, 
we must write the actual amount of liberated cations ¢ and c’, and of 
anions a@ and a’, where, of course, e+ c’ =a+a'=1; and the table 
becomes the following :— 
Results of Double Electrolysis, Sc. 
Sahat Amount of substance | Amount of substance | Total lo 
Dean lost by cathode vessel] lost by anode vessel pune eS 
A a a-a a 
A’ a! a —a! a 
C c-y Y iC 
Cc’ c—y / ce! 
AC (c—y) or (a) (y)_ or (a—a) (c) or (a) 
AIC! (a’) or (e’—y') | (a’—a") or (7’) (a!) or (e’) 
AC’ (a+y)—¢ a—(a+y¥) (a@—c) 
A’C or ¢—(a+y) or (a+y)—a or (e—a) 
This table looks more complex than the others because it contains 
alternatives; they are not ambiguities, and it is easy enough to know in 
any particular case which is the right alternative, but it cannot be 
expressed by the general symbols, because it is impossible to know 
whether c — y or a is going to be the bigger. The rule is that the 
bigger of the two alternatives about the loss of AC and A/C’ is the true 
one; and the substance formed will be at the same time decided by the 
values which in the last two alternative lines come out negative. 
Or take it conversely. Suppose A/C is the substance formed in both 
vessels as the bye-product, then the second set of alternatives are the 
right ones all through ; but if AC’ is the substance formed in both vessels, 
the first set of alternatives are correct; while, if it should happen that 
AC’ is formed in the anode vessel and A’C in the cathode, then the 
first set of alternatives are true for the anode vessel and the second set 
for the cathode vessel. 
With actual chemical substances it is usually easy to see whether the 
bye-product will be AC’ or A/C, and thus to fix the alternatives. Thus 
with a solution of copper sulphate, it is plain that the bye-product will 
be H,SO, in both vessels, and not CuO,! 
As an illustration of the possibility just mentioned, about the bye.~ 
products being different in the two vessels, consider the electrolysis of a 
’ Remember that the electrodes are supposed to be platinum, so that oxygen is 
liberated ; with a copper anode it is easy enough to form CuO, as has already been 
said. 
1885. 3B 
