141 
of the metal atoms is a saturation concentration, it immediately 
follows from this equation on application of the principle of the 
shifting of equilibrium that the equilibrium shifts to the right, r, 
being >> vr, on increase of concentration. 
It is here the place to point out how easy the application of the 
electron equation is, at least when our purpose is to indicate the 
direction of the potential changes. 
On examination of equation: 
oe KENG 
A icles ln SOEs) dr irste in CEA RE 
and the equilibrium: 
MM (lin) OL 6. es 
we can immediately answer the questions under consideration. 
When e.g. with constant total concentration we increase the con- 
centration of the Mx -ions, the equilibrium (17a) will shift to the 
left; and the concentration of the electrons (@) will decrease. 
Equation (23) then expresses that the potential difference will 
increase. 
If we raise the total concentration, the equilibrium (17a) will 
also shift to the left; also in this case the potential difference rises. 
If there were an easy way to find out the electron concentration, 
it appears from this that the electron equation would be preferable. 
8. Polarisation and passivity of metals with ions of different valency. 
We have seen that for the metals which contain only one kind 
of ions, polarisation and passivity can occur in consequence of a 
decrease of the number of ions and electrons in the surface of the 
metal caused by an insufficiently rapid setting in of the internal 
equilibrium. 
Let us now consider a metal built up of two different kinds of 
ions, then for the reason mentioned polarisation and passivity will 
take place also here, but when the internal equilibrium does not 
set in quickly enough, a second circumstance will take place here 
causing polarisation and passivity, viz. this that as was already 
shown in earlier communications, the concentration of the noble 
ion in the metal surface will increase, and that of the base ion 
will decrease. It is, therefore, clear that such a metal will be the 
most suitable material: to exhibit the phenomena of polarisation and 
passivity in all their particulars. 
We will once more elucidate this phenomenon somewhat further 
