-1820.] the Compositioti of Chloride of Sulphur. 413 



as the preceding, and the phenomena which it exhibited were 

 precisely the same. 



Now that we are acquainted with the composition of the sub- 

 bichloride of sulphur, which I subjected to analysis, the pheno- 

 mena which presented themselves during the analysis, and 

 which I have partly noticed above, admit of an easy and obvious 

 explanation. When the subbichloride is agitated strongly in 

 water, it gradually deposits one half of its sulphur. The remain- 

 ing half of the sulphur is to the chlorine in the proportion of one 

 atom to one atom. Water is decomposed by the mutual action 

 of the chlorine and the sulphur which continues united to it. 

 The oxygen of the water unites to the sulphur, and converts it 

 into hyposulphurous acid, while the hydrogen of the water 

 unites to the chlorine and converts it into muriatic acid. 



Thus one half of the sulphur is deposited while the other half 

 is converted into hyposulphurous acid. The hyposulphurous 

 acid and the muriatic acid dissolve in the water. This decom- 

 position does not take place at once, because, from the great 

 specific gravity of the subbichloride of sulphur, and from the 

 viscidity of the sulphur first evolved, great agitation and a consi- 

 derable interval of time are necessary before the two liquids can 

 come sufficiently in contact to act upon each other so as to pro- 

 duce mutual decomposition. New portions of hyposulphurous 

 acid, therefore, and of muriatic acid, are formed at each succes- 

 sive agitation, and dissolved in the water. 



But hyposulphurous acid, in order to be a permanent sub- 

 stance, requires to be united to a base. When merely dissolved 

 in water, it speedily undcioes decomposition, letting fall sul- 

 phur, and probably being converted into sulphurous acid. 

 Hence the reason why the liquid always continued opalescent: 

 it was owing to the continual decomposition of the hyposulphu- 

 rous acid, and the continual evolution of new portions of sulphur 

 in proportion as the old portions subsided : but when the hypo- 

 sulphurous acid was saturated with ammonia, its sjiontaneous 

 decomposition was stopped. This was the reason why the 

 liquid became transparent, and why I was able to separate all 

 the sulphur from it when it was saturated with ammonia. 



Hy[)Osulphurous acid is not precipitated by the salts of barytes. 

 Hence it was only the sulphuroas acid which the liquid contained, 

 and wiiich liad been formed at the expense of the hyposulphu- 

 rous acid, that was precipitated by means of the nitrate of 

 barytes. 



Nitrate of silver does not precipitate hyposulphurous acid, the 

 hyposulphite of silver being a soluble salt. Hence the reason 

 why nitrate of silver only threw down the muriatic acid leaving 

 the hyposulphite of ammonia still in the liquid, or rather convert- 

 ing it to hyposulphite of silver. l)ut Mr. Herschell has shown 

 that hyposulphite of silver is not a permanent salt, being gra- 

 duallv decomposed into water and siilplnnot of silver, llence 



8 



