HYDROGEN AND OXYGEN IN CONTACT WITH HOT SURFACES. 57 
The ratio H,/ 0 2 in the residual gas was exactly 2'0, a sufficient proof that there 
had been no permanent oxidation or reduction of the catalysing material. The 
remarkably constant values of “ Jc^ show that the rate of combination was propor¬ 
tional to the pressure of the dry gas throughout the experiment. 
In two of the three following experiments (II. and IV.), the original mixture 
corresponded very nearly to H 2 + 20 2 ; in the third experiment, normal electrolytic 
gas was employed. The rate of circulation (1 in 60 minutes) was the same for all 
three. 
Experiment II. 
November 29, 1904. 
Original mixture = H 2 + 20 2 nearly. T = 200°. Rate of 
circulation = 1 in 60 minutes. 
Experiment III. 
December 4, 1904. 
Normal electrolytic gas. T = 200 . 
Rate of circulation = 1 in 60 minutes. 
t. 
P H, 
p o„ 
%, 
Jc o 2 . 
t. 
P. 
k\. 
hours. 
0 
1 
2 
1 
If 
2“ 
millims. 
124-8 
88-8 
63-8 
44-8 
32-0 
millims. 
273-1 
255-0 
242-5 
233-1 
226-6 
0-2956 
0-2914 
0-2966 
0-2955 
0-0598 
0-0517 
0-0459 
0-0405 
hours. 
0 
1 
1 
H 
2 
3 
millims. 
380-4 
276-3 
200-0 
140-0 
96-0 
43-0 
0-2778 
0-2793 
0-2895 
0-2990 
0-3156 
— 
Experiment IY. 
December 6, 1905. 
Original mixture = H 2 + 20 2 nearly. T = 200°. Rate of circulation = 1 in 60 minutes. 
t. 
p h 2 . 
p o. 
% 2 . 
k o 2 . 
hours. 
millims. 
millims. 
0 
126-4 
244-1 
_ 
_ 
1 
2 
90-8 
226-3 
0-2874 
0-0656 
l 
66-2 
214-0 
0-2809 
0-0572 
if 
49-6 
205-7 
0-2708 
0-0495 
2 
39-0 
200-5 
0-2553 
0-0427 
H 
30-8 
196-4 
0-2453 
0-0378 
3 
24-4 
193-1 
0-2381 
0-0339 
1 
these results, which were confirmed by those of similar experiments, prove that in 
any given experiment the rate of combination is mainly determined by the partial 
pressure of the hydrogen.* If the catalytic process really involves a series of rapidly 
It may also be observed that, in the four experiments under discussion, the rate at which the 
hydrogen disappeared was practically the same, viz., about 28 to 30 per cent, during the first hour in 
each case. This clearly proves that excess of oxygen per se has no effect, accelerating or otherwise, on the 
rate of combination. 
VOL. COVI.-A. I 
