518 MR. W. C. D. WHETHAM ON THE VELOCITIES OF THE IONS. 
200nohmseie se cues Oz) SO rohms ane 
bes ook eee aL Oras ota Hess 
therefore 
y = 1°08/243, 
therefore 
v, = — 0°:000284 centim. per second, 
which, reduced to 18°, gives 
— 0000276 centim. per second. 
If this really represents the velocity of the acetate group in an acid solution, it is 
evident that, if a measurement be made of the migration constant of acetic acid, the 
concentration round the kathode must increase, since the acetate group travels in the 
same direction as the hydrogen. 
The current from twenty storage cells was passed for some hours through a deci- 
normal solution of acetic acid. The liquid was contained in an apparatus consisting 
of two upright glass tubes, in which the platinum electrodes were placed. These 
tubes were connected below the level of the top of the solution by a horizontal tube, 
made of india-rubber for part of its length, in order that it might be closed by a 
screw pinch-cock. After the passage of the current, the two vessels could thus be 
isolated from each other, and the contents of each examined. 
A current of 0°0014 ampére was passed for 5 hours, at the end of which time the 
solution round each electrode was titrated with decinormal soda solution with the 
following results :— 
Original solution . . . 10 cub. centims. require 10-0 cub. centims soda. 
Anode 55) 0 5 5 09 ” 10°4 ” oT) 
Kathode __,, rite ie $3 9°9 9 56 
This preliminary observation, therefore, gives no evidence of accumulation of acid 
at the kathode. 
The experiment was repeated. A current, whose average strength was 000178 
ampere, was passed through decinormal acetic acid solution for 383 hours. 
Original solution . . . 10 cub. centims. require 9°8 cub. centims. soda. 
Anode * eae: a 7% 9°85 9» ” 
Kathode a9 oa 9 ” 9°4 ” 2”? 
Now it is possible that an accumulation round the kathode might be masked by 
the reduction of the acetic acid by the hydrogen there liberated, but, if such an 
accumulation occurred, it would mean that all the acid decomposed must be taken 
from the anode vessel, as well as some which migrates unchanged through the liquid. 
The numbers given above seem to show conclusively that the amount of acid round 
the anode does not decrease, but that, if anything, a slight increase occurs. 
