102 
MR. P. V. BEVAN ON THE COMBINATION OF HYDROGEN 
cases the originally darkened tube in a short time showed a more rapid action, but 
this occurred only after some time. In the following experiments the tubes were 
interchanged after each experiment—the one with darkened chlorine in one experi¬ 
ment being used for the illuminated chlorine in the next experiment, and vice versa. 
The times of the observations were not recorded, but the water levels were read at 
the same instant, as all that was required was the relative rate of combination. The 
light used, being diffuse daylight on a bright day, caused fairly rapid combination, 
and the whole of an experiment occupied only from 30 seconds to 1 minute. 
Experiment 1. 
No. of reading. 
1 
2 
3 
4 
5 
6 
7 
8 
Contraction in tube containing hydrogen I 
and illuminated chlorine . ] 
2 
•t 
6 
10 
12 
14 
16 
18 
Contraction in tube containing hydrogen 1 
and non-illuminated chlorine . . . J 
•5 
0 
5 
12 
15 
18 
20 
22-5 
Experiment 2. 
No. of reading. 
1 
2 
3 
4 
5 
6 
7 
8 
Contraction in tube containing hydrogen 1 
and illuminated chlorine . ... J 
3 
6 
10 
13 
15 
16 
18 
20 
Contraction in tube containing hydrogen 1 
and non-illuminated chloi’ine . . . J 
0 
1 
3 
6 
10 
13 
17 
19 
Experiment 3. 
No. of reading. 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
Contraction in tube containing hydrogen I 
and illuminated chlorine . ... J 
2 
5 
11 
13 
14 
15 
16 
17 
18 
19 
20 
25 
Contraction in tube containing hydrogen 1 
and non-illuminated chlorine . . . J 
0 
1 
5 
7 
8 
10 
12 
13 
u 
14-5 
15 
18 
Experiments were also made with the chlorine in both tubes treated similarly—both 
tubes darkened or illuminated before the admission of hydrogen. The contraction 
observed was similar iii the two tidies, and so the initial increase in the case of the 
tube witli insolated chlorine is due to the fact that the chlorine has been influenced 
by the light. These experiments were frequently repeated with different conditions 
of Illumination, and in every case the phenomena were as in the experiments just 
tabulated. 
