466 
SIR B. C. BRODIE ON THE ACTION OE ELECTRICITY ON GASES. 
effected by the passage of an electrized gas through a solution of hydriodic acid amounts 
to twice the oxidation effected by the passage of the same gas through a solution of 
neutral iodide of potassium, but also that that oxidation is attended by an actual 
absorption of oxygen, the weight of which is equal to twice the weight of oxygen simi- 
larly absorbed by the neutral iodide. 
The previous observations were made at the temperature of the laboratory, which was 
about 18° C. to 19° C. It was important to ascertain whether by varying the tempe- 
rature the oxidation effected by the ozone could be carried beyond the limit thus reached. 
The following experiments were instituted with the view of determining this point ; the 
gas was measured in a small pipette, the capacity of which was 94 cub. centims. 
The influence of variation of temperature upon tbe oxidation of hydriodic acid effected 
by pure oxygen was first determined. In three concordant experiments made at the 
temperature of the laboratory, in which 92 cub. centims. of oxygen were passed through 
15 cub. centims. of a concentrated solution of hydriodic acid, of which solution 2 cub. 
centims. contained 1 gramme of iodine, an oxidation was effected equivalent to T7 cub. 
centim. of the standard solution of hyposulphite. This oxidation is very nearly in the 
same proportion, in relation to the volume of oxygen passed through the solution, as that 
arrived at in the previous experiments, and would amount on 250 cub. centims. of oxygen 
to an oxidation represented by 4 - 6 cub. centims. of the hyposulphite, the number given 
in the Table for a solution of hydriodic acid of this strength being 4T. The oxidation 
as similarly determined for the temperature of 53° C. to 55° C. (the mean being taken 
of four experiments) was equivalent to 4 - 6 cub. centims. of hyposulphite, and at 80° C., 
in two experiments, of which the results were nearly identical, to 6*35 cub. centims. 
At a temperature, however, of 0° C., the bulb being immersed in water containing ice, 
the oxidation in four experiments was equivalent to 1*8, 1 *9, 1*7, and 2T cub. centims. 
of hyposulphite, the mean of the four experiments being T9 cub. centim., a number 
slightly higher than that representing the oxidation at 18° C. to 19° C., namely 1*7 
cub. centim. We may conclude, therefore, that the oxidation effected by the action of 
pure oxygen on a solution of hydriodic acid of the above strength is not materially 
affected by lowering the temperature from 18° C. to zero. 
The two following experiments were made with a small pipette of the electrized gas 
at 55° C. In estimating the oxidation due to the influence of the ozone, a correction 
was made for the oxidation effected by the oxygen associated with it by deducting 4 - 6 
from the number representing the total oxidation. 
Experiments at 55° C. 
I. 
II. 
III. 
IV. 
Degree of concentration of the solution 
T. 
S. 
E— S 
of hydriodic acid employed. 
T 
2 grammes of Iodine in 2 cub. centims. 
31-4 
59-8 
1*90 
” 99 99 
31-4 
60-4 
1-92 
