BETWEEN THE VISCOSITY OP LIQUIDS AND THEIR CHEMICAL NATURE. 703 
Temperatures = t'" in degrees Centigrade at which the Slope is ‘000479. 
In order to ascertain if the values of the temperature differences given by the 
alcohols would be of the same nature at another slope, values were obtained for the 
ratio 
Absolute temperature at slope 
Absolute temperature at slope '0347 9 
Five liquids other than the alcohols, namely, formic and butyric acids, and ethylene, 
propylene, and isobutylene bromides, were also available for this comparison. These 
five liquids gave practically the same values for the ratio, the mean value being 1'24, 
and the average divergence '012, or about '90 per cent. These liquids behave, there¬ 
fore, at the large slo]oe *03479 just as they did at the smaller slopes. The alcohols, 
however, do not obey this rule, for they give ratios which are not the same, but vary 
from liquid to liquid, and are in general less than 1'24. 
The values of t" the ordinary temperatures at slope ‘0^987, and the values of t'" 
the ordinary temperatures at slope ’O 3479 , together with the ratios of these tempera¬ 
tures on the absolute scale, are given in the following table : — 
t" 
t'". 
Ratio. 
Ethyl alcohol. 
0 
58-5 
0 
- 9-8 
1-26 
Propyl alcohol. 
86-5 
25-4 
1-20 
Butyl alcohol. 
95-6 
.35-6 
119 
Isopropyl alcohol .... 
82-9 
31-7 
1-17 
Isobutyl alcohol .... 
99-6 
46-9 
1-17 
Isoamyl (inactive) alcohol . 
105-2 
49-7 
1-17 
Active amyl alcohol . 
104-7 
5.3-7 
1-16 
Trimethyl carbinol . . . 
90-9 
49-0 
1-13 
Dimethyl ethyl carbinol 
93-8 
49-1 
1-14 
Allyl alcohol. 
63-1 
4-3 
1-21 
For a normal alcohol the ratio is about 1*21 ; for an isoalcohol, about 1*17 ; and for 
a tertiary alcohol, about 1*13. The alcohols again differ in their behaviour from the 
great majority of the other liquids, and their peculiarities, as is shown in the above 
table, are related to their chemical nature. 
Conclusions relating to Temperatures of Equal Slope. 
The preceding tables show that: 
1. The magnitudes of the temperatures of equal slope vary in a regular way with 
the chemical nature of the substances, except in the case of lic[uids like formic acid, 
