290 balard's researches concerning the nature of 



acid, with the disengagement of chlorine. This peculiarity may, per- 

 haps, furnish those chemists with an additional reason, wlio think that 

 hyposulphuric acid is not a primary compound of sulphur and oxygen, 

 but a secondary combination of sulphuric acid and sulphurous acid. 



The compounds of oxygen and phosphorus do not present anything 

 similar. In fact, oxide of phosphorus, hypophosphorous acid, phospho- 

 rous acid, and even phosphatic acid, are all immediately converted into 

 phosphoric acid, with the disengagement of heat and of chlorine gas. 



The same is also the case with arsenious acid, which is converted 

 into arsenic acid, and with selenious acid, which is changed into selenic 

 acid, giving rise to the production of the same phagnomena, to an evo- 

 lution of chlorine, and a considerable disengagement of heat. 



The metallic oxides act variously with liquid chlorous acid. It will 

 be imagined that so energetic an agent of oxidation would convert the 

 greater jmrt of these compounds susceptible of it into peroxides, but 

 that it would not exert any action on those which are already saturated 

 with oxygen. This is what actually happens. The deutoxide of tin, 

 the peroxide of iron, &c. suffer no change by chlorous acid ; whereas 

 the protoxide of iron, tin, manganese, nickel, cobalt and lead are con- 

 verted into peroxides with the evolution of chlorine. The protoxide of 

 chromium is immediately converted into chromic acid. There are, how- 

 ever, some oxides susceptible of a higher degree of oxidation, such as 

 the oxide of bismuth, and the peroxide of manganese, upon which chlo- 

 rous acid does not apjjear to act. 



Although the alkaline oxides can, under some circumstances, com- 

 bine with a larger proportion of oxygen, -chlorous acid, instead of super- 

 oxidizing them, merely combines with them. Still further, it decom- 

 poses the peroxides of these metals, and disengaging oxygen it reduces 

 them to the state of protoxides, with which it forms decolorizing chlo- 

 rites. It is at any rate in this way that I have observed it to act with 

 the peroxide of barium. 



With the peroxide of lead and the two oxides of silver, which are 

 metals with which chlorine forms insoluble compounds, it acts in an 

 entirely different manner. These oxides are decomposed with the pro- 

 duction of chlorides, and not chlorites, and with a disengagement of 

 oxygen mixed with a little chlorine. This happens from the re-action 

 of chlorous acid upon the chloride formed. 



The metallic chlorides are decomposed by chlorous acid. This de- 

 composition is always accompanied with an abundant disengagement of 

 chlorine, and the metal is oxidated. As to the nature of the definitive 

 product, it evid ently depends upon the manner in which this oxide acts 

 either with chlorine or with chlorous acid. Thus the chlorides of the 

 alkaline metals form mixtures of chlorides and chlorites. Those of 

 manganese, iron, nickel, cobalt, lead, and tin, occasion a disengagement 



