BETWEEN THE VISCOSITY OF LIQUIDS AND THEIR CHEMICAL NATURE. 451 
Mean temp. 
'0 
Difference. 
Observed (mean). 
Calculated. 
0 
0-.56 
-01245 
■01245 
■00000 
5 31 
■01173 
■01177 
-h -00004 
10-45 
-01104 
-01105 
+ -00001 
1616 
-01035 
■01037 
+ -00002 
21-07 
-00983 
■00983 
■00000 
25-99 
-00934 
■00934 
■00000 
31'20 
■00888 
■00887 
- -00001 
35-86 
■00848 
■00848 
■00000 
40-93 
■00809 
■00808 
- -00001 
46-19 
■00772 
■00771 
- -00001 
50-28 
■00744 
■00744 
■00000 
56-41 
■00706 
■00706 
■00000 
Nitrogen Peroxide. N 2 O 4 . 
A quantity of this substance, prepared by heating carefully dried lead nitrate, 
was distilled, after having been frozen in a mixture of calcium chloride and ice. It 
boiled between 21°‘53 and 23°'43. Bar. 7637 millims. Corrected and reduced 
b.p. = 21°-97. 
Observations on its viscosity gave ;— 
Left limb. 
Rig 
lit limb. 
Temp. 
Press. 
Corr. 
Temp. 
Pi-css. 
Corr. 
>h 
0 
0 70 
100-14 
■000078 
■005214 
0 
0-75 
99-97 
■000078 
■005227 
5-07 
100-17 
■000081 
■004947 
5-11 
100-02 
■000081 
■004960 
9-14 
100-15 
■000085 
■004718 
9-16 
99-99 
■000085 
■004722 
11-88 
100-14 
■000087 
■004573 
11-86 
.100-00 
■000087 
■004583 
15-.33 
100-13 
■000090 
■004395 
15-39 
99 99 
■000090 
■004408 
The attempt was made to extend the readings up to within a degree or so from 
the boiling-point of the substance. The vapour of the nitrogen peroxide, however, 
acted so rapidly upon the caoutchouc connections at the higher temperatures that 
further observation was rendered impossible. 
In reducing the observations we have employed the value (/(()°/4°) = P4903 for 
the density, and the expression 
V = 1 + 0-02159U — 0-05397015/2 _p o- 0 (. 2 I 53/3 
for the thermal expansion (Thorpe, Joe. cit., p. 225). 
3 M 2 
