HYDROGEN AND OXYGEN IN CONTACT WITH HOT SURFACES. 
25 
(a) With normal electrolytic gas :— 
T = 450°. Rate of circulation = 1 in 60 minutes. 
Experiment XXVII. 
„ XXVIII. 
XXIX. 
Surface normally active 
Surface after exposure to hydrogen at 450° 
„ ,, oxygen 
h = 0-0250 
h = 0-0220 
h = 0-0218 
(i b ) With mixtures originally corresponding to 3Ho + 0 2 and H 2 + 40 2 respectively 
Experiment XXX. 
June 2, 1905. 
Original mixture = 3H 2 + 0 2 . T = 450°. Rate 
of circulation = 1 in 60 minutes. 
t. 
P H, 
p o. 
*H, 
k o 2 . 
t. 
P H, 
p o. 
k 0 2 . 
llOUl-S. 
0 
millims. 
370-7 
millims. 
123-1 
hours. 
0 
millims. 
99-3 
millims. 
397-4 
1 
357-4 
116-4 
0-0168 
0-0242 
2 
81-5 
389-0 
0-0428 
0-0046 
2 
343-6 
109-6 
0-0164 
0-0252 
4 
66-5 
381-5 
0■0435 
0-0044 
4 
315-6 
95-6 
0-0174 
0-0274 
6 
54-6 
375-7 
0-0432 
0-0041 
6 
293-8 
84-7 
0-0168 
0-0271 
8 
44-6 
370-7 
0-0434 
0-0038 
8 
271-3 
73-4 
0-0169 
0-0281 
10 
36-4 
366-6 
0-0436 
0•0035 
12 
235-2 
55-3 
0-0165 
0-0289 
18 
16-5 
356 • 8 
0-0433 
0-0026 
16 
207-2 
41-3 
0-0158 
0-0296 
22 
11-9 
353-7 
0-0420 
0-0023 
20 
184-0 
29-8 
0-0152 
0-0308 
26 
7-5 
351-5 
0-0431 
0-0021 
Experiment XXXI. 
June 20, 1905. 
Original mixture = H 2 + 40 2 . T = 450°. Rate 
of circulation = 1 in 60 minutes. 
The surface had the power of occluding hydrogen (but not oxygen) at dull red 
heat. In one experiment with pure hydrogen, carried out at 650° in the absorption 
apparatus, the pressure fell from 704 to 594 millims. during 30 minutes; this 
represented the occlusion of between 6 and 7 cub. centims. of gas, measured at 0° and 
760 millims. 
The results of the fourth series of experiments with surface D merely confirmed 
those obtained with C, and need not, therefore, be further described. 
Surface E. 
This surface had been previously used for experiments on the slow combustion 
of acetylene, and in its raw condition displayed a peculiar susceptibility to the 
stimulating influence of oxygen. Indeed, its activity was affected by previous 
exposure to hydrogen or oxygen at 450° in exactly the opposite sense to that 
observed with the surface B. This is shown by the results of the following series 
VOL. CCVI.—A. 
E 
