HYDROGEN AND OXYGEN IN CONTACT WITH HOT SURFACES. 
61 
Experiment Y. 
May 17, 1905. 
Re-oxidation of reduced surface at 160°. 
t ... . 
0 
1 
2 
3 
5 hours. 
p o 2 ■ • • 
448-2 
415-6 
396-3 
387-5 
376-3 millims. 
6 
to 
— 
0-0300 
0-0253 
0-0201 
0-0146 
The catalytic action of nickel oxide, therefore, resembles that of the reducible 
oxides contained in calcined spathic iron ore. In both cases it has been proved 
(l) that the gases will combine quite rapidly without producing any permanent 
change in the catalysing surface; (2) that the rate of combination with normal 
electrolytic gas is always proportional to the pressure of the dry gas, and far exceeds 
either the rate of reduction of the catalysing surface by hydrogen, or its rate of 
re-oxidation by oxygen ; and (3) that when the gases are not present in combining 
proportions, the rate of combination is solely determined by the partial pressure of 
the hydrogen. 
C. Experiments ivitli Copper Oxide. 
It had been our intention at the outset of the research to study the catalytic action 
of copper, as well as that of its oxide, on electrolytic gas. All attempts to obtain 
reliable velocity measurements in the case of the metal were, however, frustrated by 
the fact that at even the lowest temperature, where there was any marked action 
on the gases, the formation of steam was always accompanied by an independent 
oxidation of the surface, at least during the initial stages of an experiment. 
Nevertheless, it will be necessary to refer to one experiment with copper gauze, 
since the same gauze, thoroughly oxidised, was employed in the two following series 
of experiments. The experiment with the reduced gauze is, for purposes of comparison, 
included in the first series. 
l.sY Series. 
100 grammes of fine copper gauze, made into a long cylindrical roll, were first of 
all reduced in hydrogen at dull red heat, and subsequently heated for several hours, 
and finally allowed to cool in vacuo, in order to effect the decomposition of any 
superficial layer of hydride. 
Electrolytic gas was afterwards circulated over the reduced gauze at 214°, when 
rapid combination took place, as the following pressure records indicate :— 
