460 
SIR B. C. BRODIE OX THE ACTION OE ELECTRICITY OX GASES. 
titration after the experiment and 14'2 before the experiment, the oxidation being 
equivalent to 8 ‘5 cub. centims. 
These numbers exhibit in experiments made under the same general conditions very 
appreciable differences, and in the case of very concentrated solutions of hydriodic acid, 
as in experiment V., undoubtedly become inaccurate from the oxidation of the hydriodic 
acid during the process of titration, and also to a certain extent from variations dependent 
on the rate of the passage of the gas through the solution, and the time for which the 
surface of the solution is consequently exposed to an atmosphere of oxygen. These 
differences, however, although undoubtedly a source of error, nevertheless are very small 
as compared with the total oxidation in the analogous experiments made with an 
electrized gas, and would hardly affect the result to more than one per cent., except in 
the extreme case given in experiment V. 
The mean results of the preceding experiments are given in the two columns below. 
The numbers in column II. indicate the amount of oxidation effected by the passage 
of a pipette (that is about 250 cub. centims.) of pure oxygen at a temperature of 18° 
through a bulb, or (15 cub. centims.) of hydriodic acid, as estimated in cub. centims. of 
the standard solution of hyposulphite of soda. The degree of concentration of the 
hydriodic acid employed is indicated in column I., in which is given the number of cub. 
centims. of the solution containing one gramme of iodine. One cub. centim. of the 
hyposulphite employed was equivalent to 0‘0002814 gramme of oxygen, whence the 
actual oxidation effected can be readily calculated. For the present object this is not 
necessary. The numbers marked f are interpolated from calculation, and are the mean 
of the two experiments between which they appear. 
I. 
II. 
1 cub. centim. 
Q 
4-08 
f3 „ 
3*80 
4 
3-61 
f6 
3-00 
8 
2*22 
1-12 
1-25 
16 „ 
0*28 
In determining the oxidation effected by the action of the electrized gas upon the 
solution of hydriodic acid, the total oxidation was estimated precisely as in the experi- 
ments just described ; and a correction was made for the effect of the oxygen associated 
with the ozone by deducting from the number of cub. centims. of the standard solution 
of hyposulphite of soda which represented the total oxidation, the number of cub. centims. 
of the same hyposulphite of soda which represented the oxidation due to the passage of 
the pipette of oxygen through a solution of hydriodic acid of the strength employed in 
the experiment according to the preceding Table. This correction is made upon the 
hypothesis that the oxidation effected in the hydriodic acid is constituted of two distinct 
parts — namely, the oxidation effected by the ozone and the oxidation effected by the 
