322 
THOMPSON YATES LABORATORIES REPORT 
Assuming it to have been proved, that in the case of each electrolyte there is a 
concentration law' uniting the effects of solutions of this electrolyte in every possible 
concentration upon the value of the injury current, and that this law is always of the 
general form — 
Ew = Ea log. — 
n ' : 
where 'n' is the concentration : then in the case of each electrolyte given above we 
have a different value for the constant ' k.' 
i 
i k 
Since, in the preceding experiments, n = I ; .'. log. — = log. k. 
NaCl 
... k = 
142 
KC1 
... k = 
1 30 
LiCl 
... k = 
1-93 
NH 4 C1 
... k = 
I 22 
\ (BaCl,) 
... k = 
173 
\ (MgCW 
... k = 
I 89 
I (CaCW 
... k = 
232 
The 'concentration law' is evidently not greatly different in the case of these 
different electrolytes, the value of the constant ' k ' varying with each electrolyte to a 
not very remarkable extent. It will be seen that an allowance made for the influence 
of an important factor, not yet considered, brings even these differences approximately 
to naught, and the action of the different electrolytes within the bounds of a law 
common to them all. 
If the action of all these solutions is a purely physical one and dependent upon 
their electrical properties alone, then we have hitherto been assessing the concentration 
of the different solutions at a mistaken value. The salt which is in solution as such, 
and is not dissociated by the fact of solution, is of no account from the purely electrical 
point of view, consisting, as it does, of neutral molecules. We are alone concerned 
with the other moiety of the salt, which has been dissociated by the fact of solution 
into positively and negatively charged particles, hydrolysed into ' ions.' Such a re- 
flection discovers for us a method of regarding the so-called ' equivalent ' solutions of 
electrolytes (used in the experiments of the preceding section) in which they are seen 
as no longer equivalent, and which points to the necessity of still further checking the 
results obtained by their use. The concentrations of the solutions used have yet to 
be brought to a common standard in terms of the dissociated ions contained in them, 
before the results are made strictly comparable. 
