288 BALARD’S RESEARCHES CONCERNING THE 
part of the receivers is filled with gaseous chlorine. In this case, as 
when phosphuretted hydrogen is operated with, the disengagement of 
chlorine can only be procured on adding the gas bubble by bubble, and 
so as never to be in excess; for then it would burn at the expense of 
the chlorine itself. 
Hydrosulphuric acid acts in the same manner, but with this difference, 
that its action on the chlorous acid is not accompanied with emission 
of light, although the heat developed is very strong. There are formed 
water and sulphuric acid, and chlorine is disengaged, which afterwards 
exerts its usual action on the fresh bubbles as they arise. 
_. The phenomena are nearly the same when a current of these gases 
is passed into chlorous acid, nor does the nature of the products at all 
vary ; water, and phosphoric, arsenic, and sulphuric acids are always 
formed. The greater part of the chlorine is disengaged in the gaseous 
state, producing a brisk effervescence, whilst a portion remains liquid 
in the state of hydrochloric acid. 
Chlorous acid acts upon the liquid or gaseous hydracids nearly in a 
similar manner. In operating with hydriodic acid gas I obtained water, 
iodic acid, and a disengagement of chlorine gas. In this case a violet 
tint is, though scarcely, perceptible, which evidently arises from the 
action of chlorine set free upon some bubbles of hydriodic acid which 
have escaped the chlorous acid. Much heat, but no light, is given out 
in this experiment. 
A disengagement of heat only, occurs when chlorous acid is made to 
act upon these hydracids dissolved in water ; the decomposition is in- 
stantaneous. With hydrochloric acid, water and a disengagement of 
chlorine is produced ; with hydrobromic acid, there are obtained bromic 
acid, bromine, chloride of bromine and an abundant disengagement of 
chlorine. Hydriodic acid gives rise to similar phenomena. 
Anhydrous hydrocyanic acid and chlorous acid also exert a remark~ 
able action on each other. Chlorine is produced in abundance, and 
the liquid, besides hydrochloric acid and the cyanic acid of Sérullas, 
contains a certain quantity of chloride of cyanogen. 
The metallic sulphurets, treated with liquid chlorous acid are imme- 
diately converted into sulphates. Heat is produced, and chlorine is 
disengaged : sometimes also I have perceived the odour of chloride of 
sulphur. I obtained analogous results, in causing chlorous acid to act 
upon phosphuret of lime [ calcium? ]. 
The action of compound combustibles on chlorous acid fully con- 
firms then what itsmanner of acting upon simple combustibles had 
before indicated, and shows it to be one of the most marked agents of 
oxidation, and at the same time but little calculated to act by the chlo- 
rine which it contains. Nevertheless, when the action proceeds slowly, 
its two elements combine with the two elements of the compound com- 
