661 
Farther it is not known whether complex ions as Ag (NH), are 
hydrated too, or whether the molecules NH, have replaced the 
water molecules of the hydrated ion. 
That the water carried along bv the ions must be of influence 
on the course of the current tension line easily appears in the 
following way: The hydrated metal ions which are discharged at 
the cathode, leave their water behind. Hence there takes place an 
accumulation of water at the cathode. The solution at the cathode 
will, therefore, be more dilute than in the ease of anhydrous ions, 
as in the latter case only the ions disappear from the solution, but 
besides water is still added here. Consequently for a given current 
density a greater polarisation voltage will belong to hydrated ions 
than to anhydrous ions. 
The way in which the water liberated at the cathode disappears, 
is different from the way in which the ammonia of the complex 
ion Ag (NHL), moves away from the cathode. The released water 
can namely not move away by diffusion, because for the water 
there exists practically no difference of concentration. There will, 
however, take place a movement of the water from the cathode, 
because always a new quantity of water is liberated at the cathode, 
and this supplants the already present water. Hence the consequence 
will be that the liquid as a whole gets a movement away from 
the cathode. 
On the ground of these considerations we arrive at an equation 
of the current potential line. When a gramme equivalent of the metal 
ion carries along with it « molecules of water, then when a current 
l 
density d prevails, En gramme equivalents will be discharged 
d 
per second; hence ——_ a mol. of water will be liberated, occu- 
i lume of 18a ——— em’ 
jying a volume o Wee ent. 
a 96500 
d 
The liquid moves, therefore, with a velocity of 18a 6200 cm. 
JOU 
Den de 
per sec. from the cathode. Let a concentration difference — exist 
at 
in the diffusion layer at a distance # from the cathode, when a 
stationary state has set in. Then the quantity of ions, diffusing per 
ER dp 
second to the cathode is ——— —. 
86400 da 
As the liquid moves away from the cathode with a velocity 
