642 MESSRS. T. E. THORPE AE'D J. W. RODGER ON THE RELATIONS 
The values for the halogens obtained from monoderivatives are so related that the 
value for bromine, 372, is almost the mean of the values of chlorine and iodine 
viz., 377. 
Values oj Oxygen. 
Carhonyl Oxygen .—On deducting the values of nCHg from the observed molecular 
viscosities of aldehyde and the ketones of the general formula C^Hj^O, the differ- 
II 
ences correspond with values of carbonyl oxygen O. 
II 
C„H2„0. 
nCRn 
(calculated). 
II 
0. 
(obsei’ved). 
Dimethyl ketone. 
572 
360 
212 
Aldehyde . 
448 
240 
208 
Methyl ethyl ketone .... 
671 
480 
191 
IMethyl propyl ketone .... 
796 
600 
196 
Diethyl ketone. 
785 
600 
185 
11 
Mean value for 0 = 
198 
The average divergence from the mean is about 9 units. The mean value is 
no doubt affected by constitutive causes, as aldehyde is not strictly comparable with 
the ketones, and the isomeric ketones do not give identical molecular viscosities. 
Moreover, acetone appears from surface-energy measurements to contain molecular 
aggregates. These effects are apparently small, however, and in a first approxi¬ 
mation may be ignored. 
Hydroxyl Oxygen .—On deducting nCHg from the observed molecular viscosities 
of the acids C/^Hg^OO, values are obtained for the joint effect of an atom of car¬ 
bonyl and an atom of hydroxyl oxygen in these compounds. 
Acids. 
ij(P (observed). 
nCHj 
(calculated). 
ll\/ 
0 0. 
Formic acid. 
456 
120 
336 
Acetic acid. 
593 
240 
353 
Propionic acid. 
742 
360 
382 
Butyric acid. 
842 
480 
362 
Isobutyric acid. 
843 
459 
384 
Ii\/ 
Mean value of O O = 364 
