30 
DR. W. A. BONE AND MR. R. V. WHEELER ON THE COMBINATION OF 
Experiment V. 
July 11, 1904. 
Normal electrolytic gas after oxygen. T = 430 J . Rate of circulation = 1 in 60 minutes. 
t. 
P. 
h. 
t. 
P. 
h. 
hours. 
millims. 
hours. 
millims. 
0 
400-0 
_ 
6 
147-6 
0-0723 
] 
340-0 
0-0706 
7 
123-2 
0-0731 
3 
248-8 
0-0687 
8 
103-2 
0-0735 
4 
205-8 
0-0721 
9 
86-0 
0-0740 
5 
180-8 
0-0690 
The pressure curves for Experiments I., II., and V., which are reproduced in 
Diagram III., show very clearly the effects of “ hydrogenation” and dehydrogena¬ 
tion ” respectively on the activity of the surface. 
The results of the last four experiments of the series may be discussed together. 
Starting with the surface in the condition in which it had been left after Experi- 
rnent V., a mixture originally containing an excess of hydrogen (3H 2 +0 2 ) was 
circulated over it (Experiment VI.). Its activity was at once stimulated, and the 
rate of steam formation as the experiment proceeded was always as nearly as possible 
proportional to the partial pressure of the hydrogen. The residual hydrogen from 
VI. was circulated over the surface at 430° for 16 hours. It was then pumped out 
of the apparatus, and, on redetermining the rate for normal electrolytic gas over the 
“ hydrogenisecl ” surface (Experiment VII.), it was found to be so abnormally active 
that no less than 41*67 per cent, of the original electrolytic gas disappeared during 
the first hour, and, moreover, the stimulus outlasted the four hours over which the 
experiment extended. 
At the conclusion of Experiment VII., the combustion tube of the apparatus was 
transferred to a high temperature furnace and exhausted at dull red heat for 
16 hours, during which all the hydrogen occluded by the catalysing material was 
extracted. The tube was then cooled and refitted into the circulation apparatus. 
The rate for normal electrolytic gas was afterwards redetermined (Experiment ^ III.). 
The values of “ k” now showed that the stimulus imparted by the hydrogen had 
practically disappeared, the material being in the same “ normal condition as in 
Experiment I. Clearly, therefore, the enhanced activity of the surface after exposure 
to hydrogen at 430° in Experiment III. cannot be attributed to any chemical reduction 
of the material composing it. 
Finally, in Experiment IX., a mixture containing excess of oxygen was circulated 
over the surface. The rate of combination observed was strictly proportional to the 
