between the viscosity of liquids and their CHExMICAL nature. 059 
average difterence being 8, from which the mean divergence, neglecting signs, is 3. 
The effect of introducing the iso arrangement of two carbon atoms into a straight 
chain compound is thus taken to be — 8. 
Value of Hydrogen. 
The data used in deducing the value of H are summarised below :— 
n . 
C„Hi„ 0. 
aCHo. 
Ho. 
r 
5 
329 
400 
- 71 
Normal paraffins . . < 
6 
7 
415 
495 
480 
560 
- 65 
- 65 
L 
8 
574 
640 
— 66 
r 
5 
320 
392 
- 72 
Iso-paraffins . . . . < 
6 
405 
472 
- 67 
7 
482 
5o2 
- 70 
Mean 
value of H., = — 
68. 
Neglecting signs, the average divergence from the mean is less than 3. 
Value of Carbon. 
Since CHo = 80 and = — 68, it may be taken that CJ = 148. 
Influence of a Double Linkage. 
The four comparisons of normal propyl and allyl compounds show that the occur¬ 
rence of a double linkage and the loss of two hydrogen atoms lower the molecular 
viscosity work by 27 units, the average divergence being about 1 unit. The same 
change in a substance like ethylene bromide affects its molecular viscosity work to 
about the same extent. 
It follows, therefore, since the value of Hg is — 68, that the value of a double 
linkage is — 95. 
Values of the Halogens. 
Adopting the values, 
H = — 34, C = 148, iso grouping = — 8, double linkage = — 95, 
the data available for calculating the atomic constants of the halogens are collected 
in the tables given below :— 
4 P 2 
