1836.] Decolourizing Comhinations of Chlorine. 267 



chloride of potassium was deposited. Now, as no chlorate 

 was deposited, no deutoxide of hydrogen formed, and no 

 oxygen disengaged, it is necessary to admit that the oxygen 

 expelled from the metal by the chlorine, was conveyed to a 

 portion of this simple body, and formed with it some com- 

 bination containing less oxygen than chloric acid. It is true 

 that the fact may be explained by supposing that the presence 

 of the chloride of an oxide in the saturated solution of chlo- 

 ride of potassium has diminished, in this case, the dissolving 

 power of the liquid for this salt, and that the salt which is 

 obtained is only a portion of that which already existed in the 

 liquid, and is not produced by the action of the chlorine, as 

 Berzelius supposes. The first explanation is, however, the 

 most plausible, and leads us to suppose that the metallic chlo- 

 rides exist already formed in the decolourizing compounds. 



M. Soubeiran has confirmed the fact by an experiment 

 which appears, at present, the only one not susceptible of 

 objections. 



After determining the intensity of the decolourizing 

 power of a given quantity of chloride of soda, he evaporated 

 to dryness in a vacuum. He found that during evaporation 

 cubic crystals of chloride of sodium were formed, which 

 could be separated perfectly pure ; and that the solid resi- 

 duum, when re-dissolved in water, and poured into a neutral 

 coloured solution, possessed the property of destroying 

 colour, as powerfully as the original liquid. 



As this property was not impaired, we cannot admit that 

 the chloride of sodium was the product of the decomposition 

 of the decolourizing compound. The chloride of sodium 

 must, therefore, have existed in the solution before its eva- 

 poration. Now, if, in acting upon the alkali, the chlorine 

 had formed chloride of sodium, without the production of 

 a corresponding quantity of chlorate, peroxide of hydrogen 

 or oxygen gas, it is obvious that an acid containing less 

 oxygen than chloric acid must have been formed. 



The crystallization of the chlorate of soda in the vacuum 

 led Soubeiran to hope that he might separate the chlorous 

 acid; but the prosecution of his researches, announced 

 nearly three years ago, have not yet produced any publication. 



While the question was in this state, it appeared proper 

 to make new experiments. I conceive that I have been 



