ioo Haynes.—A Criticism of Beutner s Theory of the 
c, 
the well-known formula RT -log 
where u and v are the velocities 
u + *, 
of cation and anion in the c oil ’ phase. 
In certain cases one or other of these potentials may become negligible. 
For example, in the system 
+ NaCl M/io 
guaiacol 
KC1 M/io 
(or aniline HC1 M/io 
or MgCl 2 M/io) 
the measured e.m.f. agrees very closely with the logarithmic formula. 
In this case chemical reaction with guaiacol is probably negligible and 
diffusion potential very small, as would be the case if the various ions move 
with no great difference of velocity in the ‘ oil ’ phase. If so, Beutner’s 
very precarious method of estimating the ratio of concentrations by changes 
of conductivity would also give valid results. In other cases diffusion 
potential must be very important. This is most probable where such a salt 
as sodium oleate is in question, and will account for the divergencies from 
the logarithmic formula observed by Beutner even where free acid is 
absent. 
There is one group of experiments—expressed above by the scheme of 
System II—in which interphasic potentials play a part in somewhat different 
circumstances from those described above. Beutner has found that the 
production of an e.m.f. by difference of concentration is very largely 
dependent upon the presence of free acid and is greater with strong acids 
than with weak, but because the effect can be obtained with acids such as 
oleic acid, which are only slightly dissociated in water, he maintains that 
this effect is no ‘ measure ’ of the acidity. He looks upon it as due to 
‘non-proportional ionic distribution’, i. e. to double decomposition. To 
make Beutner’s outlook upon this matter clear, a statement will be quoted 
relating to the effect of potassium chloride on salicyclic aldehyde containing 
salicylic acid : 
‘ Soviel ist aber sicher, dass KC1 nicht nur als solches in dem saurehalti- 
gen Aldehyd zugegen ist, sondern dass die freie Base sich mit der iiber- 
schiissigen Saure vereinigt. Wie sollte sonst auch die Beobachtung zu 
erklaren sein, dass pikrinsaurehaltiges Nitrobenzol mehr Salz bei Schutteln 
aufnimmt als saurefreies Nitrobenzol? Auch in diesem Falle muss eine 
solche Umsetzung mitspielen. Das durch Umsetzung gebildete Kalisalz 
unterliegt einer elektrolytischen Dissoziation; es entstehen also in dem 
saurehaltigen Aldehyd Kaliumionen, die nicht vom KC1 herstammen. 
Um die Nichtproportionalitat der Ionenverteilung zu erklaren, ist ferner 
anzunehmen, dass die Konzentration des umgesetzten Kaliumsalzes im 
Aldehyd der wassrigen KCl-Konzentration nicht proportional ist. Wie 
dies moglich ist, kann allerdings theoretisch noch nicht begriindet werden.’ 1 
1 loc. cit., p. 97. 
