4 ART. IG. -ED WARD DIVERS. 



20(N0) , + 4S0, + 2H,0 = 2N0 + [ON(S0 3 H)„],. 



When metallic copper is used in place of sulphur dioxide, the 

 generation of the necessary sulphur dioxide by the action of the 

 metal on the pyrosulphuric acid of the nitrososulphuric acid, only 

 introduces an interesting complication. Pyrosulphuric acid at once 

 interacts with copper in the cold (/. Client. Soc, 1885, 47, G38). 



There remains to be considered the production of the "purple acid" 

 along with nitrososulphuric acid from nitric oxide and sulphuric acid 

 in the presence of cupric or ferric sulphate as a catalytic agent. The 

 sulphuric acid being represented as exsisting in its pyro-state (the 

 form in which it acts in presence of an oxide of nitrogen), the change 

 is expressed by the equation 



/S0 3 H /S0 3 H r 



6NO + 40 \ S O 3 H = <NO +K S <™°1" 



As to the peroxidising action of sulphuric acid here shown, it may be 

 well to recall the action of the acid upon metallic tin in presence of 

 hydrochloric acid (Heumann and Koechlin, Ber., 1882, 15, 420) : 



Sn + 4ClH + 0(S0 3 H),= SnCl 4 + 2S0 2 + 30H,. 

 In this equation the stannic chloride and the sulphur dioxide 

 together take the place of the peroxy lamines ulphonic acid in the 

 previous one, for [ON(S0 3 H) 2 ] 2 can evidently be expanded into 

 N 2 4 +4S0 2 +20H 2 . 



It is difficult to conceive of any other rational interpretations 

 of Sabatier's remarkable results than those given above, and these are 

 all consistent with the assumption that the purple acid is not merely 

 isomeric, but actually idelieal with peroxylaminesulphonic acid, and 

 is therefore a peroximide and an exclusively tervalent nitrogen 

 compound. 



