between the viscosity of liquids and their chemical nature. 629 
Normal compounds have higher values than the corresponding iso-compounds. The 
small difference for the butyric acids may be the result of molecular complexity. 
Aromatic Hydrocarbons. 
Difference. 
Oi-tlio-xylene. 
372 
-5 
Ethyl benzene. 
367 
1 
Meta-xylene. 
368 
-8 
Para-xylene. 
360 
Of the four isomeric CgHjo substituted benzenes, ortho-xylene has decidedly the 
largest coefficient, and para-xylene the lowest coefficient, whilst meta-xylene and 
ethyl benzene have intermediate and almost identical values. 
Isomeric Ketones. 
7- 
Difference. 
Diethyl ketone. 
Methyl propyl ketone. 
343 
344 
1 
The isomeric ketones give identical coefficients, the effect of constitution being 
apparently inoperative, probably for the reason already given. 
Dichlorethanes. 
7- 
Difference. 
Ethylene chloride. 
Ethylidene chloride. 
377 
35.5 
- 22 
The isomeric dichlorethanes give values which differ widely, the symmetrical com¬ 
pound being the more viscous. 
