390 PEOrESSOE BUNSEJT AKD DE. H. E. EOSCOE’S PHOTO-CHEMICAE EESEAECHES. 
porous cells filled with, hydrochloric acid or water, it is possible to hberate any desired 
volume o£ chlorine, oxygen, or hydrogen, the amounts of which, uninfluenced by any 
variation in the intensity of the cuiTent, always stand in a constant relation to the volume 
of chlorine and hydrogen evolved by the primary current. In this manner we have 
procured mix tures of gases of constant composition which we have used in the following 
experiments. 
The observations, which were carried on through a veiy considerable space of time, 
were only made use of, w^hen, by repeatedly leading the gas through the apparatus, we 
had convinced ourselves that the maximum action of the induction had been reached. 
The mixtm’e of gas containing excess of hydi’ogen, used in the fii’st experiment, was 
easily analysed by collecting a portion of the mixtm’e, allowing the chlorine and hydrogen 
to combirre hr the light, and measuring the residual hych’ogen. It contained orrly 
irrore hydrogen than the normal electrolytic gas. The first vertical division of the fol- 
lowing Table gives the times of observation, the other dhisions give the actions corre- 
sponding to the times, effected at a temperature of 16°’3 C. and a barometric pressrrre of 
0“’755, and measured by the volumes of hydrochloric acid formed in one minute. 
Series of Experiments VI. 
Tinse of 
observation. 
Normal gas. 
Normal gas 
hydrogen. 
Ditto, after 
further 
saturation. 
Normal gas. 
0 
1 
15-6 
8-3 
7-3 
17-7 
2 
24-0 
12-5 
13-5 
28-1 
3 
27-1 
14-6 
13-6 
30-2 
4 
29-9 
14-6 
16-6 
37-9 
5 
38*5 
15-8 
12-5 
43-5* 
6 
38-5 
15-4 
13-6 
? 
7 
44-7* 
18-2* 
12-5 
43-0 
8 
43-3 
15-2 
12-2 
42-0 
9 
16-2 
14-2 
44-0 
10 
17-2 
14-2 
43*0 
11 
16-2 
15-2 
12 
17-7 
16-2* 
13 
16-2 
14 
15-7 
The rnearr irrduction-maximum of the normal gas was at the hegmirirrg of the experi- 
merrt 43-85, and at the end of the same 43-10 ; the photo-cherrrical composition of the 
normal gas had therefore not charrged durirrg the course of the experiment. This 
maximum actiorr 43-47 of the normal gas, diminished by addition of x^yo of hydr-ogen 
to 16-78 hr the fir-st experimeirt and to 16-03 hr the secoird, or in mean to 16-40. The 
gaseous mixture was expanded by this additiorr of hych’ogen from 1 to 1-003; this 
exparrsion would be effected by a charrge of temperatme frour 16°-3 to 17‘^-1 = 7, as is 
seerr from the equation 
( 1+0-00.S66X 16-3) ]_ 
^ (1+0-00366x0 “■1‘003’ 
