between the viscosity of liquids and their chemical nature. 609 
Isologous Hydrocarbons. 
CnHjn+j. 
C„H2„. 
C„H 
2 «_2- 
C,(Ho„^g. 
n. 
t‘. 
Diff. 
t'. 
Diff. 
t'. 
Diff. 
t'. 
o 
o 
0 
o 
o 
o 
0 
5 
- 5-4 
14-8 
-20’2 
6-7 
-12-1 
6 
20-5 
• • 
10-8 
9-7 
-55-4 
75-9 
7 
41-1 
-26-7 
67-8 
8 
64-1 
• • 
• • 
-13-8 
77-9 
On converting a saturated into a straigbt-cbain unsaturated hydrocarbon the 
temperature of slope is lowered, amylene giving a larger difference than isoprene or 
diallyl. The large negative values of the differences given by the aromatic hydro¬ 
carbons point to the influence of the ring-grouping, and their variation to the 
anomalous behaviour of benzene already noted. 
Substitution of Halogen for Hydrogen. 
Diff. 
Chlormetlianes. 
n. 
t'. 
t'. 
t'. 
Diff. 
o 
0 
o 
o 
0 
2 
147-8 
120-9 
26-9 
Methylene chloride 
37-1 
29-5 
3 
144-6 
89-9 
54-7 
Chloroform .... 
66-6 
38-3 
4 Iso. 
161-3 
84-9 
76-4 
Carbon tetrachloride . 
104-9 
On substituting bromine for hydrogen the temperature is largely increased, and 
the amount varies somewhat with the chemical nature of the substance. The succes¬ 
sive replacement of hydrogen by chlorine increases the temperature by different 
amounts. ^ 
Compounds differing by a Carbon Atom. 
t'. 
Difference. 
t'. 
Difference. 
Tetrachlormethane . 
Tetrachlorethylene . . 
10°4-9 
98-4 
O 
-6-5 
Mfcthyl alcoiiol.... 
Aldehyde . 
o 
76-0 
-16-8 
o 
-93 3 
The entire want of agreement between the values of the differences given in the 
4 u 2 
