G82 
MESSRS. T. E. THORPE AND J. W. RODGER ON THE RELxVTIONS 
Difference. 
Observed. 
Calculated. 
Methyl alcohol. 
260 
260 
Ethyl alcohol. 
367 
364 
3 
Propyl alcohol. 
449 
468 
- 19 
Butyl alcohol. 
570 
672 
_ 2 
In deducing the value of CH 3 the molecular viscosity work of propyl alcohol was 
ignored, as there is little doubt, from the low boiling-point of the sample, that its 
viscosity is affected by impurity. It is conceivable, of course, that the discrepancy 
in the case of this alcohol may be due to mathematical treatment of the results, for 
in the case of the alcohols Slotte’s formula is least satisfactory, as dr]jilt is so large 
that a small error in determining the slope corresponds to a large error in the 
ascertained viscosity. In this particular case, however, a graphical method of 
obtaining the slope led to ^practically the same result as the analytical method. The 
difference in the case of propyl alcohol is about 4 per cent., and in the case of ethyl 
and butyl alcohols the differences are only about '6 per cent. It is therefore probable, 
that in normal pi’imary fatty alcohols, CII 3 , as in other homologous series, corresponds 
to a constant change in molecular viscosity work, and that the magnitude of this 
change differs from that in other series, and is about 104 units. 
A primary straight chain alcohol may be represented as 
II(CH2)„0H, 
on deducting values of nCHg, that is, w( 104), from the observed values of the alcohols, 
the differences obtained correspond with the value of H. . . OH. 
The data are given in the table :— 
n. 
H(CH3)„0H. 
mCHj (calculated). 
H.. .OH. 
ijd^ (observed). 
1 
260 
104 
156 
0 
367 
208 
159 
3 
449 
312 
137 
4 
570 
416 
154 
Propyl alcohol, as before, gives a number differing considerably from the others; 
excluding this, we conclude that the probable value of H .. . OH is 15G. 
