eS = Of 
A , 
. ’ 
e 
482 Mr. R. Hosking on the Electrical 
have to overcome is mainly friction between this atmosphere 
and the solvent water. 
In a later paper, Kohlrausch * has explained more fully 
his previous paper, and has sketched out the new view of the 
mechanics of electrolysis, according to which the moying ion 
carries with it a mass of adhering ‘solvent, and the electrical 
resistance of an ion is a frictional resistance which increases 
with the dimensions of the atmosphere surrounding it. 
One of the conclusions he arrives at is that the resistance 
of an ion expressed in mechanical units must be of the same 
order of magnitude as the mechanical resistance of a molecule 
of the solvent. 
The velocity of the ions will depend on the viscosity of the 
medium through which they pass, and on the size of the 
10n1¢ atmosphere ; and the conductivity of the solution will 
depend on the viscosity of the medium, the size of the ionic 
atmosphere, and the fraction of dissociated ions in solution. 
The lithium ion, which moves very slowly, may be considered 
as the centre of a larger atmosphere than the fastly moving 
chlorine ion, and probably with rise of temperature the 
atmospheres will approach the same size, as Kohlrausch has 
observed that with rise of temperature the velocity of the 
ions tend to become equal. 
If we examine our weakest solution, we shall see that here 
the conductivity does not keep pace with the molar fluidity 
as the temperature is raised, although there is no combination 
of the ions. It looks as if the aimosphere around the neyga- 
tive ion is Increasing rapidly, while that around the positive 
ion remains constant or diminishes slowly. 
If for our solution at infinite dilution we take the value 
C 
i= 1:048 at 18° C., and consider the atmosphere of the Cl ion 
to have unit radius, that of the Li ion will have 2 times 
this radius at the temperature 18° C., because the Cl ion moves 
twice as fast, and the retardation will depend on the square 
of the radius. 
Now : at 100°='946. The ratio has decreased in the 
proportion 1-048 : *946 or 1-11 to 1. This decrease is due to 
the increase of the atmosphere of the ions, and as these atmo- 
spheres tend to become equal, if we assume that at 100° they 
are equal, the radius of each will be 1:29, so that the Cl has 
increased its atmosphere by °29, and the Li has diminished 
its by '12. 
= Kohlrausch, Roy. Soc. Proc. Feb. 17, 1908. 
