IN GASES: HYDROGEN, CARBONIC OXIDE, AND OXYGEN. G67 
Table XXXV. 
1 
Before the explosion. 
After the 
exploion. 
Temp. 
a. 
rveiei eiicc 
No. 
Oxygen. 
Carbonic 
oxide. 
Hyd rogen. 
Carbonic 
oxide. 
Ca- bonic 
acid. 
Hydrogen. 
Steam. 
Ill 17'6 
73'4 
26-G 
53'5 
19'9 
11-7 
14-8 
° C. 
16 
34 
112 
,, 
•)) 
52-2 
21-2 
12-8 
1.3-8 
30 
2-7 
113 ! 
i1 
52-1 
2D4 
12-6 
14-0 
60 
2 7 
114 | 
? J 
11 
52-0 
2E4 
12-7 
13-9 
100 
2-7 
The maximum tension of aqueous vapour at 16° is 13^ millims., at 30° it is 31-| 
millims. ; the tension of the steam produced in the unimpeded reaction is 14 millims. 
As the temperature is reduced from 100° to 30°, no alteration is found in the coeffi¬ 
cient ; at 16° the coefficient is distinctly raised. The constant coefficient under 
100 millims. is lower than that under 400 millims. 
From all the experiments made at various temperatures, it follows that when the 
steam formed during the reaction is more than sufficient to saturate the space at the 
temperature of the enclosing vessel, some of the steam is condensed on the sides of the 
vessel during the progress of the chemical change. 
By the removal of a 'portion of the steam during the reaction, more steam and less 
carbonic acid are found after the explosion than if all the steam had remained as a gas 
capable of reacting with the carbonic oxide. 
When no condensation occurs, a change of initial temperature has no effect on the 
division of the oxygen in the explosion. 
Experiments on the “ critical pressure” at high temperatures. 
In the experiments previously described, in which portions of a mixture were 
exploded under increasing pressures at ordinary temperatures, it was found that the 
ratio of carbonic acid to steam formed continually diminished until at about 400 
millims. pressure it became constant. The lowest pressure at which the ratio became 
constant varied in different mixtures. The larger the percentage of oxygen taken, the 
lower the critical pressure was found to be. In these experiments, condensation of 
CO 
steam occurred during the reaction, and in consequence the ratio ppp^ was diminished. 
In the temperature experiments last described, it was seen that this ratio varied with 
the pressure when no condensation took place. To determine the amount of this 
variation, and the “ critical pressure,” with different mixtures, three series of explosions 
were made under successively increasing pressures, at a temperature sufficiently high 
to prevent any condensation of steam. In the first series a mixture of nearly equal 
volumes of carbonic oxide and hydrogen was taken. I 00 volumes of this mixture 
were exploded with 15'4 volumes of oxygen at 80°. 
4 q 2 
