1835.] Decolourizing Combinations of Chlorine. 265 



of some chemists may be correct, that chlorine, in acting 

 upon coloured bodies in contact with water, produces its 

 bleaching effect by an indirect oxidation, induced by its 

 disposition to unite with hydrogen. Welter made an experi- 

 ment which appeared to decide the question in favour of 

 the active agent being a chloride of an oxide. This chemist 

 found that the bleaching power of chlorine was constant 

 whether the gas was free or dissolved in water, or whether 

 it was combined with an oxide. 



This remarkable fact could not easily be explained, but 

 by supposing that the chlorine, in each instance, was in an 

 analogous state. If, therefore, it were admitted that it was 

 in a state of solution in the water saturated with chlorine, 

 it would be necessary to grant that it was united with the 

 oxide in the bleaching compound; or, if the latter was a 

 chlorite, it was necessary that the solution of chlorine should 

 be a mixture of chlorous and muriatic acids. Chemists in 

 general adopted the first supposition. Berzelius, alone, 

 preferred the second explanation, although it was less 

 probable. 



The experiments of Soubeiran have since thrown light 

 upon this subject. They proved that the observation of 

 Welter was only correct with a solution of indigo in sulphuric 

 acid ; the latter decomposing the bleaching compound, and 

 setting at liberty all the chlorine which formed it. But, if 

 a neutral ink or a coloured vegetable infusion be employed, 

 the bleaching power is not the same ; and we observe that 

 its influence is increased by setting free the chlorine con- 

 tained in a solution of the chlorides by means of an acid. 



This property, which the decolourizing chlorides possess, 

 of allowing the whole of the chlorine which they contain 

 to be disengaged by the action of the weakest acids, such 

 as carbonic acid, has been regarded as an argument in 

 favour of the chlorides of the oxides ; and it must be allowed 

 that the phenomena of decomposition are much more easily 

 accounted for on this supposition than by the other. Nothing 

 is more easily conceived than the action of an acid uniting 

 to a base, and thus disengaging the simple body with which 

 it formed a temporary compound. But the disengagement 

 of the chlorine il also readily explained by the hypothesis 

 of the chlorites : for we can easily conceive that the chlorous 



