94 



DIVERS AND HAGA. 



sulphur dioxide, so that the decomposition lies between those expressed 

 by the equations : — 



4AgN(S03Ag\,=2N2+2SO., + 5>^(),Ag,+ 8Ag2 

 4AgN(S03Ag),= '2N2 + 4S0, + 4SO,Ag2 + t^Ag^, 



but nearer the iirst one. 



The salt was pre])ared for analysis Iw addino- the sodium salt 

 gradually, with stirring, to excess of silver nitrate. In spite of the 

 strongly alkaline reaction of the former, the mother- liquor of the 

 precipitate proved to be neutral, as it should be, while the precipitate 

 was not in the slightest l)ro\vii, but brilliantly white. Being unde- 

 composed by \Yater it was washed. Its analysis gave, besides the 

 0*55 per cent, water mentioned above, the following results : — 



Diargentuin sodimn imidosiilphonate. — The sandy precipitate, de- 

 scribed above, is a salt with two atoms of silver to one of sodium. It 

 is sparingly soluble in water and very slightly decomposed by it, 

 silver hydroxide being one of the products. It has a faint buff colour. 

 Its crystals are seen under the microscope to be hexagonal plates, 

 always single, which rotate polarised light. This salt, though other- 

 wise anhydrous, retains a little water with the same firmness as that 

 shown by the wholly silver salt. Its behaviour when heated closely 

 reseml)les that of the latter, except that, naturally, sodunn sulphate 

 forms }\art of the residue, as well as silver sul|)hate. 



To prepare the salt for analysis, the sodium salt was added 

 gradually to a little less than two-thirds of its equivalent of silver 

 nitrate. The sandy precipitate obtained was only slightly washed, 



