THOMPSON YATES LABORATORIES REPORT 
Experiment I 
13-46 x log. (18-2, k) = 4-22 
log. (l8 2, k) = -31 = log. 2 
.-. k = — = -n 
l8'2 
Experiment II 
1 3'99 lo g- (36-3, k) = 871 
log. (36-3, k) = -62 = log. 4-16 
,. k = q 6 = 11 
Experiment III 
15-84 x log. (145-2, k) = 19-27 
log. (145-2, k) = vii = log. 16-2 
, 16-2 
.-. k = = 11 
145-2 
Experiment IV 
18-48 log. (290-4, k) = 28-25 
log. (290-4, k) = 1-51 = log. 32-5 
.-. k = l 2 ^- = -II 
290-4 
' k ' therefore is in reality a constant, and the law which unites the effects of solutions 
of hydrochloric acid is simple, and is — ■ 
E w = E a log. — 
n 
The discovery of such a ' concentration law ' has two important results. The 
first of these is undoubtedly the strong confirmation of the value of the line of 
reasoning which led to its discovery, namely, that based primarily upon the opinion 
that the source of E.M.F. of the injury current is due to a difference between the 
solutions in contact with the electrodes, such as may be described as a solution ' con- 
centration cell.' The second is the strong indication that valuable information is to 
be obtained from the observed effects of solutions of other electrolytes ; if attention is 
paid to the numbers of which the ratios between the final and the initial potential 
difference are the logarithms, and not to these ratios themselves. The value of such 
an indication is seen by a consideration of the experiments given in the preceding 
table. 
