24 
DR. W. A. BONE AND MR. R. V. WHEELER ON THE COMBINATION OF 
Normal electrolytic gas. T = 430°. Rate of circulation = 1 in 45 minutes. 
Experiment. 
Date. 
Condition of surface. 
h 
for time interval 
0 to 2 hours. 
XXI. 
February 17, 1905 
N ormal 
0-0175 
XXII. 
„ 19, 1905 
5) 
0-0165 
XXIII. 
March, 1, 1905 
After exposure to hydrogen in the 
cold for one week 
0-0299 
XXIV. 
„ 3, 1905 
After two days’ exhaustion at 430° 
0-0201 
XXV. 
„ 4, 1905 
Normal 
0-0170 
XXVI. 
„ 14, 1905 
After exposure to hydrogen in the 
cold for ten days 
0-0328 
1 
Another interesting feature about, the behaviour of this surface was that in every 
experiment with mixtures containing an excess of oxygen, the activity was initially 
rapidly stimulated up to a fairly high limit, after which the rate of combination 
depended on the partial pressure of the hydrogen only. But whilst this enhanced 
activity was undoubtedly due to the excess of oxygen, it ceased as soon as all the 
hydrogen had disappeared. In other words, the surface was not stimulated under 
the influence of oxygen alone, either at 450° or at dull red heat, but only by an 
excess of oxygen in presence of hydrogen, and whilst the gases were actually 
combining. This peculiarity is well illustrated by the results of the following series 
of experiments at 450° :— 
