HYDROGEN AND OXYGEN IN CONTACT WITH HOT SURFACES. 
51 
experiments, which were carried out at 160°-170°, show that the action of platinum 
is not materially different from that of the other metals examined. In the following 
experiments a piece of platinum gauze (18 strands, each 0'12 millim. in diameter, per 
centimetre), 7'5 centims. long and 2‘7 centims. broad, weighing 2'67 grammes, was 
employed. The area exposed to the reacting gases would, therefore, be approxi¬ 
mately 27'5 sq. centims. The rate of circulation was the same in all experiments, 
namely, 1 in 65 minutes, but the temperature varied somewhat in different 
experiments between the above limits. 
Experiment I., which gives the “ normal” value of “ Jc” for the series, proves that 
with normal electrolytic gas the rate of combination is proportional to the pressure. 
In Experiment II., where the original mixture corresponded very nearly to H 2 + 20 2 , 
the rate was throughout proportional to the partial pressure of the hydrogen, 
although the values of “ /tjj ” indicate that the gauze was more than normally active. 
Experiment III. gives the rate for normal electrolytic gas after the residual oxygen 
from II. had been circulated over the gauze for 16 hours; there was no evidence of 
any stimulation. Experiment IV. merely confirms the results of II. 
In Experiment V. the value of “ k” for normal electrolytic gas was re-determined, 
and in VI. an original mixture corresponding to 3H 2 + 0 2 was employed. The rate of 
combination was again nearly proportional to the partial pressure of the hydrogen 
throughout. The residual hydrogen was afterwards circulated over the gauze at 165° 
for 16 hours and finally quickly withdrawn from the apparatus. On re-determining the 
rate for normal electrolytic gas over the “ hydrogenised ” surface (Experiment VII.) 
it was found to be abnormally active. The stimulus, however, rapidly wore away as 
the experiment proceeded, entirely disappearing after 30 minutes. 
Experiment I. 
November 26, 1904. 
Normal electrolytic gas. 
T = 165-8°. Rate of 
circulation = 1 in 65 
minutes. 
Experiment II. 
November 27, 1904. 
Original mixture = H 2 + 20 2 nearly. 
T = 169-173°. Rate of circulation = 1 in 
65 minutes. 
Experiment III. 
November 28, 1904. 
Normal electrolytic gas after 
oxygen. T = 170-2°. Rate 
of circulation =1 in 65 
minutes. 
t. 
P. 
h. 
t. 
P H„ 
p o. 
M. 
*o 2 . 
t. 
P. 
h. 
horn’s. 
0 
millims. 
308-8 
hours. 
0 
millims. 
123-7 
millims. 
248-5 
hours. 
0 
millims. 
368-9 
1 
236-6 
0-1157 
1 
68-9 
221-1 
0-2541 
0-0508 
1 
2 
326-3 
0-1066 
2 
191-5 
0-1038 
H 
50-1 
211-7 
0-2617 
0-0464 
1 
286-9 
0-1091 
3 
155-4 
0-0994 
9JL 
25-9 
199-6 
0-2716 
0-0381 
H 
252-3 
0-1101 
4 
124-5 
0-0987 
3 
18-9 
196-2 
0-2719 
0-0342 
2 
214-8 
0-1174 
5 
99-9 
0-0980 
3i 
13-9 
193-7 
0-2712 
0-0310 
91 
183-5 
0-1212 
6 
77-6 
0-0999 
4 
10-3 
191-8 
0-2699 
0-0281 
3 
162-6 
0-1186 
7 
8 
56-6 
40-7 
0-1052 
0-1100 
4-|- 
7-3 
190-3 
0-2730 
0-0259 
H 2 
