426 M. Balard on the Nature of the [Dec. 



separation of chlorine and carbonic acid, which is easily 

 accomplished by means of mercury. Various trials were 

 made in this way, which, although all indicating that the 

 volume of the chlorine was almost double that of the oxygen, 

 differed, however, too much from this result, which was so 

 various as to diminish my confidence in it. 



Convinced, however, that it was not owing to errors in 

 experiments that these different results were obtained ; the 

 liquid being tested with nitrate of silver, after a decomposi- 

 tion of this kind, it was proved that some of the chlorine 

 was retained in the liquid. It was clear that the quantity 

 retained increased in proportion as the acid was more 

 diluted. It is not certain in what state the chlorine exists 

 in the liquid ; perhaps it may be in the form of chloroxalic 

 acid, which Dumas formed by exposing acetic acid and 

 chlorine to the action of the solar rays. Perhaps, also, it 

 may be in the state of muriatic acid, which might be formed 

 by the decomposition of the acid, carbonic acid being dis- 

 engaged. Inaccurate as this method is, it appears to prove 

 that chlorous acid is composed of two volumes chlorine 

 and one of oxygen. But its action with muriatic acid dissi- 

 pates any doubt on this head. Chlorous and muriatic acids 

 produce, by double decomposition, as has been already 

 stated, water and chlorine. Now, if upon a given quantity 

 of muriatic acid, an excess of chlorous acid is allowed to act, 

 the proportion between the volumes of the acid gas decom- 

 posed, and of the chlorine obtained, may enable us to deduce 

 the composition of the chlorous acid from that of the muri- 

 atic itself. 



This decomposition was attempted, either by passing 

 muriatic acid gas over mercury, in a graduated tube, con- 

 taining at its upper part, a small portion of very concen- 

 trated chlorous acid,"*^' or by introducing chlorous acid into 

 a tube already containing some muriatic acid gas. But the 

 decomposition in both cases was very imperfect. The fol- 

 lowing method, however, succeeded well : — 



Having filled, over a mercurial trough, a flask ground 

 with emery, with dry muriatic acid gas, a small glass globe 



• For the complete decomposition of these two acids, it is necessary that the 

 chlorous acid be very concentrated, because they may co-exist without decom- 

 posing each other when they are in a certain state of dilution. 



