SIE B. C. BEODIE ON THE ACTION OF ELECTEICITY ON GASES. 
437 
free, and consequently expand to their normal bulk, or two volumes, 
6 6 o+Hg 2 =Hg 2 o+o 6.” 
Soret * subsequently discovered that if oil of turpentine or oil of cinnamon be brought 
in contact with oxygen containing ozone as procured by electrolysis, a diminution occurs 
in the volume of the gas. Soret inferred (from his experiments) this diminution in 
volume to be equal in amount to twice the expansion which another portion of the same 
gas underwent when heated, or (what ought to he the same thing) to twice the volume 
of oxygen absorbed from the same gas by neutral iodide of potassium. 
Although I quite agree that this is really the case, at least with the ozone procured 
by the action of induced electricity upon oxygen, I must be excused for saying that the 
experiments of Soret by no means justify the conclusion. The mean ratio of the 
observed diminution in volume to the oxygen absorbed by neutral iodide of potassium 
was in the case of the first set of five experiments 2 ’4, a number which cannot be con- 
sidered even as an approximation to the theoretical number 2 ; and the similar mean of 
the second set of seven experiments, in which the ratio was estimated of this diminution 
to the expansion which the same gas underwent when heated, was T81, a number 
exhibiting a considerable divergence in the other direction from the same theoretical 
value f. Soret, indeed, gives a preference to these last experiments, and among these to 
three experiments especially, which show a closer concordance with theory ; but this 
preference seems rather to be based on a foregone conclusion in favour of the theory 
than from any superiority in the experiments themselves. The truth is that no precise 
value at all for these contractions is really indicated by the experiments, and the errors 
are too great for any theory to be based upon them. These deficiencies are doubtless 
in no way to be attributed to any want of care or skill on the part of the experimenter, 
but to the unavoidable errors in the method of experiment. 
About the time of the publication of Soret’s experiments I was myself engaged with 
the same subject of inquiry, and, indeed, before the publication of these experiments had 
ascertained the nature of the contraction (hereafter discussed) which an electrized gas 
undergoes when passed through a solution of neutral hyposulphite of soda. Numerous 
circumstances, many beyond my control, have unfortunately interfered with the prose- 
cution of these researches, of which, however, I at last am able to lay the results 
before the Society. 
Section I. 
The chief difficulties in the way of the accurate investigation of this problem have 
arisen from the absence of any adequate method of experiment; and I shall now proceed 
to describe an apparatus by which these difficulties may he obviated, and by which I 
have been enabled to generate and collect the electrized gas in sufficient quantities for 
examination, to submit successive portions of the same gas to the action of various 
* Ann. Ch. Phys. (4) vol. vii. p. 113. t Loc. cit. pp. 116 & 117. 
3 o 2 
