388 PEOFESSOE BIJNSEN AND DE. H. E. EOSCOE’S PHOTO-CHE^nCAL EESEAECHES. 
The first vertical column of the following Table contains the times of observation, 
beginning at the point at which the light was admitted ; the following columns contain 
the corresponding action of the light expressed in volumes of hydrochloric acid formed 
in the unit of time. The second vertical column gives the action for gas which has not 
been before exposed to the light, the follo’wing di’visions for gas which was allowed to 
stand in the dark for thirty, two, four, eight, and sixteen minutes after the induction 
had been fully attained. 
Series of Experiments V. Observation A. 
No. 6. 
No. 7. 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
No. 5. 
Time in 
Non-induced 
Induced 30' in 
Ditto, 2' in 
Ditto, 4' in 
Ditto, 8' in 
Ditto, 16' in 
Mean of 
minutes. 
gas. 
dark. 
dark. 
dark. 
dark. 
dark. 
Nos. 6 and 7. | 
0 
0-5 
0-0 
0-0 
1-2 
0*5 
0*5 
0-0 
i 
0-0 : 
1-0 
0-0 
0-0 
4-5 
2-5 
I’O 
0-0 
0-0 ' 
1-5 
0-0 
0-5 
5*0 
5-0 
? 
1-0 
0-3 
2-0 
0-0 
0-2 
5-3 
5-3 
5-0 
3-0 
0-1 
2-5 
1-0 
0-8 
5-7 
5-2 
5-6 
4-4 
0-9 
3-0 
2*0 
2-1 
4-5 
5-2 
5*6 
5*8 
2-1 
3-5 
3-5 
4-3 
5-5 
5-0 
5-8 
6-2 
3-9 
4-0 
4-5 
4*3 
5-5 
6-0 
5-0 
O'l 
4-4 
4-5 
4-0 
5-2 
5-0 
5-0 
6-0 
5-9 
4-6 
5-0 
5-0 
6-5 
5-0 
5-0 
5-0 
5*8 
5"5 
5-0 
5-0 
... 
... 
... 
... 
5-0 
Observation B. 
With an insolation-vessel eight times smaller than that employed in obseiwation A. 
No. 6. 
No. 7. 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
No. 5. 
Time in 
Non-induced 
Induced 30' in 
Ditto, 2' in 
Ditto, 4' in 
Ditto, 8' in 
Ditto, 16' in 
Mean of 
minutes. 
gas. 
dark. 
dark. 
dark. 
dark. 
dark. 
Nos. 6 and 7. 
0 
0-5 
0-0 
0*0 
5-1 
3-1 
1-0 
? 
0-0 
1 1-0 
0-0 
0-0 
6-6 
6*1 
4-2 
2*2 
0*0 
1-5 
O'O 
0-0 
6*3 
6-1 
6-1 
2-5 
0-0 
2-0 
2-7 
1-0 
6-3 
6-1 
6-6 
5-0 
1-9 
2-5 
5-2 
3-0 
6-1 
6-3 
4-1 
3-0 
5*2 
3-5 
... 
• •• 
6-0 
4-4 
3-3 
6-2 
5-5 
... 
» • • 
5-9 
4-0 
6-3 
6-0 
6-2 
The last columns in both sets of observations contain the mean action of the gas 
which had not been at all exposed to hght, and that which by standing in the dai’k had 
completely regained its original properties. 
From these experiments we may conclude, — 
(1) That the resistance to combination overcome by the influence of the ligiit is soon 
restored when the gas is allowed to stand in the dai'k. 
(2) That whether the induced condition be completely or only partially removed by 
exclusion of light, it always returns by insolation accordmg to the same law, and that the 
