96 
SIE B. C. BRODIE ON THE ACTION OE ELECTRICITY ON GASES. 
diluted with ^ of its bulk of a solution of strong- hydrochloric acid. The reaction was 
unaffected by these circumstances. But in the case of similar experiments made with 
electrized oxygen very different results were obtained. In three experiments thus made, 
in which the strength of the solution of the tin salt was the same as in experiments 1 
s 
and 2, 5 - 89, 6 - 49, 7‘14 were severally obtained for the value of the ratio The con- 
clusion to he drawn from these experiments, taken in connexion with those on the same 
subject given in my previous paper, is that the oxidation effected in a solution of proto- 
chloride of tin by oxygen gas is greatly diminished and retarded when the oxygen is 
diluted with a large proportion of carbonic-acid gas, whereas the oxidation effected in 
the protochloride of tin by passing ozone through the solution is unaffected by such 
dilution. The influence of the carbonic-acid gas in thus preventing the combination of 
oxygen may be compared to the influence of even a small proportion of the same gas in 
extinguishing combustion. 
When ozone prepared from pure oxygen is passed through a solution of hydriodic 
acid of such a degree of concentration that not less than one gramme of iodine is con- 
tained in 8 cub. centims. of the solution, the average oxidation effected was found to be 
equal to twice that effected by the passage of an equal volume of the same gas through 
a solution of neutral iodide of potassium*. But this oxidation is considerably reduced 
when the electrized oxygen is largely diluted with carbonic-acid gas, as is shown by the 
following experiments, which were made with an electrized gas obtained by passing 
through the induction-tube a mixture of oxygen and carbonic acid in the proportion of 
one volume of the former to nine volumes of the latter gas. A pipette of the capacity 
of about 100 cub. centims. was employed to measure the gas; the temperature and 
pressure were constant throughout the several experiments. 
In column I. is given the degree of concentration of the hydriodic acid employed. In 
column II. is given the titre of a pipette of the gas with neutral iodide of potassium, T, 
as represented by the cub. centims. of hyposulphite of soda necessary for the titration. 
In column III. is given the titre of a pipette of the same gas with hydriodic acid, S, 
similarly represented. | In column IV. is given the ratio of the oxidation effected in the 
hydriodic acid to the oxidation effected in the neutral iodide of potassium, B,=?- 
The independent oxidation effected under these circumstances by the oxygen mixed 
with the ozone must be very small, since in an experiment similarly conducted, in which 
a bulb containing the solution of hydriodic acid was placed after the bulb of neutral 
iodide employed for the titration of the gas, no oxidation whatever was effected in the 
second bulb by the passage of the oxygen. I have therefore not attempted to make any 
allowance for this oxidation ; in other respects the experiments were conducted as those 
before referred to. In the case of the last four experiments in the Table I have no 
memorandum of the degree of concentration of the hydriodic acid employed. 
* Philosophical Transactions, loc. cit. p. 462. 
