PEOFESSOE BTES’SEN AND DE. H. E. EOSCOE’S PHOTO-CHEMICAL EESEAECHES. 373 
A . R = (B . Vo + Cip) a (Wo — W„) ; and hence 
A T? 
W _W -1- 
“ ” a (BVq + CjP)' 
In order to be able to employ the experiments communicated in Series VII., page 3G9, 
for the calculation of (Wo— W„), the volumes read off on the divided scale were reduced 
to cub. cent., and placed in the following Tables : — 
Series of Experiments IX. 
Experiment 1. 
Experiment 2. 
Experiment 3. j 
Time. 
Volume 
in 
cub. cent. 
Diminution 
of volume in 
one second. 
Time. 
Volume 
in 
cub. cent. 
Diminution 
of volumein 
one second. 
Time. 
Volume 
in 
cub. cent. 
Diminution | 
of volume in : 
one second. | 
Insolated 0 0 
1 0 
2 0 
Darkened 3 0 
3 10 
3 20 
3 30 
3 40 
3 50 
4-20926 
4-19983 
4-19078 
4-18136 
4-18023 
4-18008 
4-18000 
4-18000 
4-18000 
0-000157 
0-000151 
0-000157 
0-000113 
0-000015 
0-000008 
0-000000 
0-000000 
/ // 
Insolated 0 0 
1 0 
Darkened 2 0 
2 10 
2 20 
2 30 
2 40 
2 50 
4-20255 
4-19199 
4-18143 
4-18030 
4-18008 
4-18000 
4-18000 
4-18000 
0-000176 
0-000176 
0-000113 
0-000022 
0-000008 
0-000000 
0-000000 
Insolated 0 0 
0 30 
Darkened 1 0 
1 30 
2 0 
2 30 
4-20929 
4-19660 
4-18453 
4-I8O75 
4-18000 
4-18000 
i 
1 
0-000423 
0-000402 i 
0-000126 
0-000025 
0-000000 1 
i 
The constants required for this calculation are, — 
s, =2-4531 
s =1-2612 
Ci=0-0324 
c =0-2114 
a - 0-677 
C =669-9 
P = 0-7497 
W„=20°-9 C. 
y) =0-0120 
The values of A and B, and from these (Wo— W„), calculated from these data, are found 
in the following Table, in which the variables Vo and E. are placed in the first and 
second horizontal divisions : — 
Exp. 1. 
Exp. 2. 
Exp. 3. 
Vo 
4-18136 
4-18146 
4-1845 
R 
0-000157 
0-000155 
0-0004128 
A 
0-96859 
0-96859 
0-96859 
B 
0-0003144 
0-0003144 
0-0003144 
(W„-W„)... 
0°-13 
0°-13 
0°-35 
These results prove that the photo-chemical combustion of the chlorine and hydrogen 
mixture may be increased from 12 or 14 divisions in the minute up to 32 or 35, whilst 
the increase of temperature accompanying this increased action amounts only to 0°-2 C. 
As various later experiments have shown that differences of several degrees in tempera- 
ture do not affect the combining power of the chlorine and hydrogen mixture to any 
appreciable extent, we may answer the fu-st question as follows : — 
