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IY. On the Action of Electricity on Gases. — II. On the Electric l Decomposition of 
Carbonic-acid Gas. By Sir B. C. Brodie, Bart., B.C.L., F.B.S., late Waynflete 
Professor of Chemistry in the University of Oxford. 
Received June 19, — Read June 19, 1873. 
At a very early period of the investigation on the action of electricity upon oxygen, 
which formed the subject of my previous memoir*, the idea occurred to me that 
although but a small and limited proportion of the total oxygen passed through the 
induction-tube was converted into ozone (which proportion could not be exceeded by 
any modification I had been able to effect in the conditions of the experiment), it might 
he practicable to replace that portion of the oxygen which was unaffected by the action 
of electricity by an indifferent gas, and thus effect the total conversion of oxygen into 
ozone, or even the actual isolation of the ozone by the subsequent removal of the gas 
by which it was diluted. Thus, for example, by the passage of 100 cub. centims. of 
oxygen through the induction-tube, a gas can readily be obtained of which the iodine- 
titre is 5 cub. centims. This corresponds, according to my previous experiments, to an 
absorption by hyposulphite of soda of 10 cub. centims. of a gas containing in that 
space the matter of 15 cub. centims. of oxygen. If, therefore, we were to mix 15 cub. 
centims. of oxygen with 85 cub. centims. of an indifferent gas which should be unaffected 
by the action of the electricity, and pass the mixed gases through the induction-tube 
(assuming the same proportion of ozone to be still formed as in the case of the passage 
through the tube of pure oxygen), the total amount of oxygen in the gas would be con- 
verted into ozone, and be removed in that form by passing the gas though a solution of 
hyposulphite of soda. With the view of testing this idea by a critical experiment, I 
passed such a mixture of carbonic-acid gas and oxygen through the induction-tube. 
The formation of ozone was at once apparent, and was rendered evident by the action of 
the gas issuing from the induction-tube upon a neutral solution of iodide of potassium. 
Bat on examining the composition of the gas I soon discovered that the proportion of 
oxygen in it had actually increased, owing to the decomposition in the induction-tube 
of the carbonic-acid gas into oxygen and carbonic oxide. I did not publish this experi- 
ment ; but the apparatus by which it was effected long stood upon my laboratory table, 
and, together with the results, has repeatedly been explained by me to other chemists. 
Since that time, as appears from the pages of the ‘ Comptes Bendus,’ this decomposition 
of carbonic-acid gas under the influence of electricity has been cited as a novel discovery. 
So far as the bare fact of the decomposition of carbonic-acid gas, under the influence 
* Philosophical Transactions, Part II. 1872, p. 435. 
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