4jo 
It is evident from the above table tliat in all cases the value of 
the temperature coëfficiënt is about 0.024. Now, from the researches 
of Boüty 1 ) it is seen tliat the temperature coëfficiënt of fluidity of 
alcohol is about 0.024 per degree centigrade. Thus for almost all 
the salts studied, the temperature coëfficiënt of conductivity in alco- 
holic Solutions is equal to the temperature coëfficiënt of fluidity 
of the Solutions; because the Solutions being very dilute, their 
viscosities are practically identical to that of the pure solvent, namely 
alcohol. 
From a consideration of equal effect of temperature on the con- 
ductivity and fluidity of aqueous electrolytie Solutions of pure water, 
Kohlrausch 2 ) presents the hypothesis that, round everj* ion, and 
raoving along with it, there is an atmosphere of the solvent whose 
dimension is determined by the individual characteristics of the ion; 
and the electrolytie resistance of an ion is a frictional resistance 
which increases with the extension of the atmosphere, the direct 
action bet ween the ion and the outer portion of the solvent dimin- 
ishing as the atmosphere becomes of greater thickness. This hypo- 
thesis is in agreement with the fact that the most sluggish ions 
have the temperature coëfficiënt of resistance very like the tempe- 
rature coëfficiënt of viscosity of the solvent. The hypothesis is in 
further agreement with the eircumstance tliat the temperature formula 
for the mobility of the ions shows in all cases a convergence towards 
the zero value between — 35° C. and — 41° C., the zero value of 
the fluidity of water being reached at — 34° C. 
From our work it is evident that the same hypothesis may be 
applied equally in alcoholic Solutions. The electrolyte binds with 
it a few molecnles of the solvent, the alcohol, which forms an 
atmosphere round it, and it moves througb the solution with this 
alcoholic atmosphere surrounding it. The frictional resistance it meets, 
is not the frictional resistance between the ions and the solvent 
alcohol, but it is the frictional resistance of the alcoholic atmosphere 
round the ions against the solvent molecules. 
Chemical Labomtory, 
Presidency College, Calcütta. 
J ) Jour. de Physique (2). 3, 351 (1884). 
2) Proc. Roy. Soc. 1903, 71, 338. 
