20 
DR. W. A. BONE AND MR. R. V. WHEELER ON THE COMBINATION OF 
led us to investigate the separate influence of hydrogen and oxygen respectively at 
430°. and also of hydrogen at red heat, upon the catalysing power of the surface. 
At 430°. 
The general plan of this series of seven experiments (XII. to XVIII. inclusive), all 
made with normal electrolytic gas at 430°, under precisely the same conditions as 
regards rate of circulation, was briefly the following : 
Before each experiment (except the first, which was simply made to determine the 
“ normal ” value of the reaction constant “ k, ” for the series), either hydrogen or 
oxygen was circulated over the surface at 430 for a period ot time vaiying horn 
24 to 72 hours. The gas was then rapidly -withdrawn from the apparatus by means 
of the auxiliary Sprengel pump, the action of which was continued for about 15 or 20 
minutes after the manometer had indicated a moist v acuum. A chaige of 
electrolytic gas was immediately admitted, and the rate of combination determined 
over a period of 8 or 10 hours in the usual manner, finally, the apparatus was again 
thoroughly exhausted. The furnace was never turned down during the whole of the 
five weeks over which the series of experiments extended, and the apparatus was 
kept exhausted during the intervals between each experiment. The rate of circulation 
in each experiment was 1 in 35 minutes. 
Experiment XII .—In this experiment, in which electrolytic gas was admitted to 
the apparatus without any preliminary treatment of the surface with eithei hydiogen 
or oxygen, the mean value for “ ” was found to be 0'0363. 
In two of the three following experiments (namely, XIII. and XY.), the surface was 
subjected to a preliminary treatment with hydrogen at 430° for 24 and 40 hours 
respectively, and in the third (XIV.) to the action ot oxygen for -M houis. The 
results are tabulated below :—• 
Experiment XIII. 
May 3 and 4, 1904. 
Preliminary treatment with hy¬ 
drogen at 430° for 24 hours. 
Rate of circulation = 1 in 35 
minutes. T = 430°. 
Experiment XIY. 
May 7 and 8, 1904. 
Preliminary treatment with oxy¬ 
gen at 430° for 24 hours. Rate 
of circulation = 1 in 35 minutes. 
T = 430°. 
Experiment XY. 
May 9 to 11, 1904. 
Preliminary treatment with hy¬ 
drogen at 430’ for 40 hours. 
Rate of circulation = 1 in 35 
minutes. T = 430’. 
t. 
P. 
h. 
t. 
P. 
h. 
t. 
P 
h. 
hours. 
0 
2 
4 
6 
8 
10 
1 
millims. 
397-4 
313-5 
252-5 
211-4 
177-4 
149-4 
0-0515 
0-0492 
0-0457 
0-0438 
0-0425 
hours. 
0 
2 
4 
6 
8 
millims. 
388-4 
337-6 
297 -0 
257-5 
228-0 
0-0305- 
0-0291 
0-0291 
0-0287 
hours. 
0 
2 
4 
6 
8 
10 
millims. 
347-9 
264-8 
203-5 
155-1 
120-8 
89-0 
0 0592 
0-0582 
0-0584 
0-0578 
0-0592 
