HYDROGEN AND OXYGEN IN CONTACT WITH HOT SURFACES. 
49 
Experiment XIII. 
December 20, 1904. 
Normal electrolytic gas over “ de¬ 
hydrogenised ” surface. T = 250°. 
Rate of circulation = 1 in 45 
minutes. 
Experiment XIV. 
December 22, 1904. 
Original mixture = H 2 + 2 O 0 nearly. T = 250° 
circulation = 1 in 45 minutes. 
Rate of 
t. 
P. 
ki. 
t. 
p h 2 . 
p o. 
"h,„ 
'■■o. 
hours. 
millims. 
hours. 
millims. 
millims. 
0 
399-2 
— 
0 
109-3 
218-7 
— 
— 
1 
355 • 3 
0-1013 
1 
96-3 
212-2 
0-0550 
0-0132 
1 
317-0 
0-1002 
2 
88-1 
208-1 
0-0468 
0-0108 
2 
255 • 9 
0-0966 
3 
81-6 
204-8 
0-0423 
0-0095 ; 
3 
200-1 
0-1000 
5 
70-2 
199-2 
0-0385 
0-0081 
4 
161-3 
0-0984 
7 
60-0 
194-0 
0-0372 
0-0074 
5 
127-4 
0-0992 
9 
50-7 
189-4 
0-0370 
0-0069 
11 
43 • 5 
185-8 
0-0364 
0-0064 
The Absorption of Hydrogen by the Gold Gauze at 600°. 
The results of the foregoing experiments led us to try the action of hydrogen upon 
the gauze at 600° in the absorption apparatus.* The fall in pressure in each of two 
experiments amounted to from 30 to 40 millims. out of 760 millims. during the first 
hour, and in the third experiment the total fall in pressure was 105 millims. during 
20 hours. The occluded gas was retained in a vacuum at the ordinary temperature, 
but could be readily extracted at dull red heat. A microscopic examination of the 
gauze revealed no signs of disintegration, or of the formation of a hydride, as in the 
corresponding experiment with silver. The immediate cause of the catalytic action 
would, therefore, seem to be a merely superficial occlusion, or condensation, of 
hydrogen, rather than the formation of a hydride or any deep action of the gas. The 
following re-determination of the rate of combination for normal electrolytic gas at 
250°, after the treatment with hydrogen at 600°, showed how greatly the catalysing 
power of the surface had been stimulated. 
* In speaking of his experiments on the action of hydrogen upon gold at red heat, Graham remarks: 
“ The power of this metal to occlude hydrogen is very sensible.” In one experiment it occluded 0 - 48 of 
its own volume of the gas (‘Phil. Trans.,’ 1866, vol. 156, p. 433; ‘Chemical and Physical Researches,’ 
p. 275). 
YOL. CCYI. •—A. 
H 
