G58 
MESSRS. T. E. THORPE AND J, W. RODGER ON THE RELATIONS 
xylene the smallest; meta-xylene and ethyl benzene have practically the same value, 
and this is almost the mean of those of ortho- and para-xylene. 
Dichlorethanes. 
)]CP. 
Difierence. 
i 
Ethylene cliloilde. 
Etlivlidene chloride. 
326 
312 
-14 
The symmetrical compound has, as before, the larger value. 
Isomeric Ketones. 
,jfP. 
Difference. 
Diethyl ketone. 
Methyl propyl ketone. 
376 
383 
7 
Probably for the reason already given, the imsymmetrical compound has the larger 
A'alue. 
It will be apparent from these tables that the relationships thus established are as 
definite as those given by the molecular viscosities of the substances, and justify the 
attempt to calculate atomic constants which is given in detail in what follows. The 
method is the same as that used in the case of molecular viscosity. 
Method of Deducing the Fundamental Viscosity Constants (Molecular 
Viscosity Work at Slope ‘04,323). 
Value o/CH,. 
The mean of the twenty-three available values for CMg given in the table of homo- 
logues is practicall}^ 80 (79‘52) and, neglecting signs, the average divergence from 
the mean is 5. Hence it is assumed that 
CHo = 80 . 
Infiuence of the Iso grouping. 
Excluding the butyric acids, for the reason already given, all the comparisons agree 
in showing that a normal compound has a higher value than an iso compound, the 
