]4 ART. 15,— TAMEMASA HAGA. 



es its instability. Acids hasten the decomposition of the salt ; 

 alkalies retard it. When drained on the tile from an alkaline 

 solution, the salt may, under cover, remain undecomposed for two 

 hours or more ; but if washed on the tile and thus deprived of the 

 traces of its adherent alkaline mother liquor, it will decompose in a 

 very few minutes. Nevertheless, on one occasion, some of the salt 

 thus purified was kept on a tile for 11 months in a desiccator, and 

 only then decomposed through an accident. This, however, must be 

 regarded as a very uncommon experience. The sensitiveness of 

 potassium peroxylaminesulphonate to acids has been recorded by 

 others, but has been somewhat exaggerated. When the salt is free 

 from every trace of nitrite, its cold acidified solution may remain 

 coloured for 40 minutes. An alkaline solution may not lose all its 

 colour when kept in a closed vessel for more than a month. If 

 sufficiently pure, the solid salt may be preserved for a day or so 

 under water rendered slightly alkaline with potassium hydroxide. 



The nature of the decomposition of potassium peroxylamine- 

 sulphonate occurring in the absence of alkali has already been examined, 

 although in all cases very imperfectly, by Fremy and by Claus, and 

 in the presence of alkali by Raschig. According to Fremy, the 

 solid salt decomposes explosively when heated ; when exposed to the 

 air it becomes strongly acid ; and when heated in solution it yields 

 sulphate and a gas mistaken by him for oxygen, but which is really 

 nitrous oxide. He was also mistaken in stating that it melts 

 readily and that when left in a closed bottle it evolves nitric oxide. 

 Claus found that, whether in the solid state or in solution, whether 

 when cold or moderately heated, the decomposing salt yields hydroxvl- 

 aminetrisulphonate and nitrous oxide, together with acid sulphate 

 equivalent to one-fourth of its sulphur, according to the equation 

 2K 4 X S S 4 M + ILO = 2KHS0 4 + 2K 3 XS,0 lft + N s O. Haschig has confirm- 



