THE BLEACHING COMPOUNDS OF CHLORINE. 297 
gas has the penetrating odour of chlorocarbonic acid. Nitrous oxide 
gas does not appear to undergo any alteration by chlorous acid; but 
with nitric oxide gas this acid occasions a violent detonation. This is 
accompanied with the production of nitrous gas, which fresh bubbles of 
chlorous acid are susceptible of converting into nitric acid. 
Sulphurous acid gas, when dry, is but slowly attacked by chlorous 
acid; yet, after some hours, the gaseous mixture placed over mer- 
eury disappears, and the sulphurous acid is converted into sulphuric 
acid. 
Filtering paper and indigo are the only organic matters which I have 
put in contact with chlorous acid gas. The first occasioned detonation, 
but very little carbonic acid was produced. The receiver, after the 
explosion, was found full of oxygen and chlorine, nearly in the propor- 
tions which constitute chlorous acid; this indicates that it was chiefly 
by the heat disengaged in its action on the paper that the gas detonated. 
Indigo also decomposes chlorous acid without detonation, and con- 
verts it into a compound of a yellow colour. The volume of carbonic 
acid produced is much smaller than that of the oxygen contained in 
the acid employed; and the chlorine evolved is in part absorbed by the 
mercury, and partly retained in the pores of the vegetable matter, 
which yields, undoubtedly from this cause, acid vapours when heated. 
The facts which I have now detailed prove, as it appears to me, 
that chlorous acid in the state of gas acts nearly in the same way as 
when it is liquid. If its two elements are absorbed together when 
the temperature is but little raised, it is on the other hand principally 
owing to the oxygen gas which it contains that it acts whenever much 
heat is emitted. The disengagement of chlorine gas which accompanies 
the greater number of its re-actions appears to me to be a sufficient 
proof of the truth of this assertion. ; 
It may be thought at first that the chlorine comes from the decom- 
position of a portion of the gas, occasioned by the high temperature 
which the: action of a combustible body most commonly develops; 
but only one portion of the chlorine can be attributed to such an 
origin. In fact, the quantity of oxygen with which it is mixed, is al- 
most always smaller than that which in chlorous acid is united with 
the volume of chlorine obtained; which induces the opinion, that in 
these cases the two combustible elements of the compound are princi- 
pally combined with oxygen. 
§ 5. Composition of Chlorous Acid. 
_ The experiments which I have now related are sufficient to determine 
that the new compound, which I have described under the name of 
chlorous acid, is uniformly composed of chlorine and oxygen; but they 
do not determine the proportions in which these two elements are united. 
