700 
MESSRS. T. E. THORPE ARD J. W. RODGER ON THE RELATIONS 
above comparisons is, no doubt, the result both of chemical constitution and of the 
molecular complexity of methyl alcohol. 
Isomers. 
Normal and Iso Compounds. 
Normal. 
Iso. 
t'. 
Difference. 
t'. 
0 
0 
o 
Pentanes . 
- 5-4 
- 10 
- 4-4 
Hexanes. 
20-5 
4-5 
16-0 
Heptanes. 
41-1 
5-4 
85-7 
Propyl iodides. 
83-6 
3-7 
79-9 
Propyl bromides .... 
54-7 
3-1 
51-6 
Propyl cldorides .... 
26-4 
5-0 
21-4 
Butyric acids. 
138-3 
9-2 
129-1 
A normal compound has a temperature which is in general slightly larger than 
that of the corresponding iso compound. The large dilference given by the acids 
is, in all probability, the result of complexity. 
Aromatic Hydrocarbons. 
Difference. 
O 
o 
Ortbo-xylene. 
91-3 
-13-4 
Etliyl benzene. 
77-9 
- 7-3 
Meta-xylene. 
706 
4-5 
Para-xylene. 
751 
The large difference given by ortho-xylene is connected with the striking peculiarity 
in the course of the curve for this substance, as compared with those of the other 
isomers. The temperatures of the other isomers differ at most by some 8°. 
Dichlorethanes. 
t'. 
Difference. 
1 
o 
0 
Ethylene chloride . 
93-7 
-41-5 
Ethylidene chloride. 
52-2 
The symmetrical compound has here by far the higher tempei’ature. 
