66 DE. W. A. BONE AND ME, E. V. WHEELEE ON THE COMBINATION OF 
The fall in pressure during the first hour in the above experiment corresponded 
to the disappearance of only 5'2 out of the original 213'3 millims. of hydrogen, 
or less than 2\5 per cent. On subsequently circulating pure hydrogen over the 
gauze at the same temperature (214°), the pressure fell from 331 to 100 millims. 
in an hour, representing the disappearance of no less than 70 per cent, of the gas. 
3 rd Series. 
A final series of experiments was made in which the combustion tube was packed 
with granular copper oxide such as is used in the analysis of organic compounds. 
The material had previously been heated to dull redness in a current of air for. 
6 hours, and afterwards in a stream of oxygen for 12 hours longer. The followino- 
two experiments were then made at 200° : (1) with normal electrolytic gas (IX.), and 
(2) with a mixture of hydrogen and nitrogen corresponding very nearly to 2H 2 + N 2 (X.). 
The rate of circulation was 1 in 45 minutes in each case. It will be observed that 
whereas only 9"7 per cent, of the original hydrogen disappeared during the first hour 
in Experiment IX., no less than 50 per cent, of the gas disappeared when nitrogen 
was substituted for the oxygen of the electrolytic gas. 
Experiment IX. 
Original mixture = 2H 2 + 0_>. 
Eate of circulation = 1 in 45 minutes. 
Experiment X. 
Original mixture = 2H 2 + N 2 . 
Eate of circulation = 1 in 45 minutes. 
t. 
P. 
k\. 
t. 
P. 
P H, 
/,: h 2 . 
hours. 
No permanent f 0 
reduction of 1 1 
the copper | 2 
oxide. . . ^ 3 
H 2 /0 2 = 2-0. 
millims. 
488-8 
441-7 
399-1 
360-0 
0-0440 
0-0440 
0-0443 
hours. 
0 
1 
9 
3 
millims. 
333-5 
226-0 
162-3 
131-9 
millims. 
210-7 
103-2 
38-5 
8-1 
0-3100 
0-3690 
0-4720 
4 
5 
6 
H 2 /0 2 = 1-82. 
319-0 
284-5 
242-0 
0-0465 
0-0470 
0-0509 
8 
10 
11 
Ho/Oo = 1-47. 
169-5 
120-3 
97-8 
0-0575 
0-0608 
0-0635 
It is a significant fact that during the first three hours in Experiment IX., when 
the pressure in the apparatus was fairly high, there was no permanent reduction 
