MR. W. C.D. WHETHAM ON THE VELOCITIES OF THE IONS. oly 
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It is, therefore, probable that, just as ferric chloride decomposes into ferric 
hydroxide and hydrochloric acid, thus : 
FeCl, + 3H,0 = Fe (OH); + 3HCl, 
so ferric acetate gives ferric hydroxide and acetic acid, thus : 
Ble (©. Ee Os) iris Or etie| (OI) -13) (ECs EO): 
In each case most of the work of carrying the current is done by the acid. 
An attempt was made to use the red colour of the ferric acetate as an indicator to 
show the presence of the acetate group. A decinormal solution of ferric chloride was 
placed in one limb of the apparatus, and a similar solution, coloured red by a little 
ferric acetate, in the other. It was thought that, by the motion of the colour 
boundary, the acetate group could be traced, and, since the current is almost 
exclusively carried by the free acid, that the velocity thus measured would be that of 
the anion of acetic acid in dilute solution. 
When the current was applied, however, it was at once seen that the colour 
boundary moved in the same direction as the current—not against it as an anion 
should. The following measurements were obtained :— 
Resistance of ferric chloride solution in a third cell at 18°°8 = 363 ohms. 
ie =: 34 + acetate solution in Cell No. 2 at 18°°9 = 384°5 ohms. 
Cell constant = 2'356. 
Therefore mean conductivity at 19°°2 = 6°35 x 107°. 
Velocity.—Half-hour intervals. Current upwards. Displacement upwards : 
Current downwards. Displacement downwards : 
ey, iS Reni ele 
Mean velocity = 0°833 centim. in 30 minutes. 
Mean galvanometer veading = 46°2. Resistance of galvanometer = 218 ohms. 
Graduation with a Daniell cell : 
