288 balard"s researches concerxixc 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 phaenomeua 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 ; Avater, and phosjjhoric, arsenic, and sulphuric acids are always 

 i'ormed. 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 phaenomena. 



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 SeruUas, 

 contains a certain quantity of chloride of cyanogen. 



The metallic sulphurets, treated with liquid chlorous acid are imme- 

 diately converted into sulpliates. 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 its manner 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- 



