1G DR. W. A. BONE AND MR R. V. WHEELER ON THE COMBINATION OF 
combination was greater in III. than in IV. The values of “ K given m the 
following table are calculated from the expression - log ~; it will be seen that m 
each experiment the rate of combination varied directly with the piessuie of the di\ 
gas. # 
Experiment III. 
March 7, 1904. 
T = 430°. Rate of circulation = 1 in 20 minutes. 
Experiment IV. 
March 14, 1904. 
T = 430°. Rate of circulation = 
1 in 30 minutes. | 
t. 
P. 
k\. 
t. 
P. 
k\. 
hours. 
0 
millims. 
406-7 
hours. 
0 
millims. 
411-8 
2 
322-5 
0-0503 
2 
343-3 
0 - 0395 
4 
259-4 
0-0486 
4 
283-5 
0-0405 
6 
203-0 
0-0501 
6 
230-3 
0-0420 
8 
159-6 
0•0507 
8 
188-5 
0-0424 
10 
12 
125-5 
0-0510 
10 
155 - 6 
0-0422 
97-1 
0-0519 
12 
126-2 
0-0424 
14 
76-1 
0-0520 
14 
106-0 
0-0422 
16 
58-7 
I 
0-0526 

The pressure curve for Experiment IV. is shown in Diagram 11, Curve B, p. 15. 
The gas remaining in the apparatus at the end of Experiment IV. was withdrawn 
and analysed ; it contained 
H 2 = 66'1, 0 2 = 33-2, and N 2 = 07 per cent.f 
The nitrogen would correspond to rather less than 0’2 per cent, in the original gas. 
2nd Group.—Showing the Influence of Excess of either Hydrogen or Oxygen 
respectively on the Rate of Combination. 
The primary object of these experiments was to test the validity ol the “ diliusion” 
theory. If the observed rate of change in a heterogeneous gas system is determined 
by diffusion factors only, it must, at any given moment, depend on the rate at which 
the eras in defect at the surface diffuses on to it from the outside inert atmosphere. 
c? 
* That the combination was entirely a surface phenomenon was proved by a “blank” experiment in 
which the catalysing material was removed and normal electrolytic gas continuously circulated at a 
pressure of 478 millims. through the empty combustion tube at 430° for 6 hours. There was, however, no 
fall in pressure. This blank experiment, therefore, shows also that the glass surface of the combustion 
tube had no appreciable influence at 430° on the course of events. 
f [Added February 10, 1906.—Since nothing but steam was produced in the above experiments, this 
analysis proves that the gas obtained by the electrolysis of a solution of pure barium hydroxide contains 
hydrogen and oxygen in exactly equivalent proportions.] 
