1490 
We shall now follow the method applied by van Laar *) in the 
derivation of Nernsv’s formula. 
Let us now execute the usual splitting np of the molecular ther- 
modynamie potential : 
e= RT INC. sets oe ee ARAG) 
in which u’ for diluted states is only a function of the temperature ; 
we then get starting from (12): 
wy a Wis + RT In MM) — RT In 1) 
n= EN ERE a (5) 
if we put in this: 
en PA 2 ce ee eae eee 16 
Ms M L M ( ) 
we get 
RT (Ms) 
MSS OT Ape eet 5 sor LF 
F | n K u n Ur | (17) 
or 
Jb K'y: (Ms) 
= / = = aha Nao 7e 
A F | n (Mi) (17a) 
If we now start from the equation (13), we arrive in quite the 
same way at the equation 
ne RT ee (As) 18 
—= Tan n B n (97 je 5 5 5 5 = 0 ( ) 
or 
Rr Kid 
en |» ed ea ik ee BE) 
I (41) 
When by a thermodynamic way the formula for the potential 
difference had been derived by van Laar, it was demonstrated by 
Smits?) what the physical meaning is of the quantity A, which 
oceurs in vAN Laar’s final formula instead of the Lösungstension P. 
Now we can find in the same way the physical meaning of the 
products A’ (M's) and AK (As) in equations (17a) and (18a). 
It follows from equation (17a) that 
L110 
when 
CU Ui ive UUs Ta vas ver a (25) 
In this case also 
J) Chem. Weekbl. 41, 1905, 
Lehrbuch der theoretischen Elektrochemie (1907). 
2) These Proc. IX, p. 2. 
