POTASSIUM NITROSOSULPHATE. 93 



trites and sulphites, the expanded formula K*ON"'NO'S0 3 K, according 

 to which nitrososulphates are simple sulphates of the radical, M'ON 2 — 

 (where M is a univalent metal or ammonium). 



There are three objections which can be raised to this conception 

 of their nature. One, made by Pelouze sixty years ago, may be stated 

 almost literally in his words. Is it probable that nitrous oxide, con- 

 tained as such in these salts, can, by the small rise of temperature 

 upon which it becomes nitric oxide, take oxygen from such a stable 

 compound as sulphuric acid ? We reply that, since the oxygen which 

 has converted sulphite to sulphate has not, in doing so, parted with 

 the nitrogen of the nitric oxide, it may well enough be expected to 

 keep it when, by a sufficient elevation of temperature, the complex 

 molecule of the salt has to break up, though even then, as at lower 

 temperatures, some of it does leave nitrogen in order to remain in the 

 sulphate. 



Another objection which may suggest itself, as it also did to 

 Pelouze, to these salts being sulphates, is that they give no precipitate 

 of sulphate with barium chloride. But this may only show that they 

 resemble alkyl sulphates, such as the sulphovinates ; whilst the 

 instantaneous precipitation of barium sulphate on addition of an acid 

 confirms the view as to their sulphate constitution, since all known 

 sulphazotised salts of the sulphonic type take a notable time to begin 

 to precipitate barium sulphate when acidified, brief though that time 

 may be in the case of the trisulphonated nitrile salts, during which 

 hydrolysis is taking place. 



A third and obvious objection to the view that nitrososulphates 

 are true sulphates is that they resist decomposition by alkalis. It is 

 here admitted that a constitution in which nitrogen is shown in direct 

 union with sulphur would furnish, prima facie, a more satisfactory 

 ground for their stability than one in which it stands only in 



