IMIDOSULPHONATKS. 



93 



closely resembles wlute sea-sand (silver-saud). A salt of the same 

 composition as this often occurs ns a htird, crystalline incrustation on 

 the sides and bottom of tlie beaker, when to the mother- H(juor of the 

 felted crystals a little silver nitrate is added. 



(Some experiments with potassium imidosulphonate have o-iven 

 us salts apparently analogous to those got from the sodium salt, but 

 we have not further examined them). 



Tn'argentum imidosulphonate.* — By adding the S(^dium salt in 

 limited quantity to silver nitrate, the white precipitate is also formed, 

 and is now permanent in its mother- liquor, This precipitate, which 

 is triai'gentum imidosulph<mate, is very httle soluble in water, and after 

 long v>ashing on the filter yields a milky filtrate. It is •> relatively 

 voluminous preci]>itate forming chalk-like masses when drv. It is 

 without water of crystallisation, as was to be anticipated, but even 

 wlien kept long at 110° retains 0*5 5 per cent, of water (possiblv fixed 

 by hydi-olysis from the atmosphere), ;is determined by combustion 

 with copper oxide. It bears heat well, but at a comparatively high 

 tem])eratui'e rapidly decomj^oses with or without fusion, giving in 

 the open tul^e first ;i very little ammonia g;is and sublimate, then 

 sul])hur dioxide, nitrogen, silver, silver sulphide, and silver sul])hate. 

 When heated in a vacuum, scarcely any sublimate is fornied. and no 

 change takes ])lace till the temperature reaches 440°, when gas comes 

 oif, and blackening without fusion occurs. The residue consists of 

 silver sul])hate, siher sulphide, and silver, and the gas of nitrogen 

 and sulphur dioxide. The proportions of these ])roducts vary a, little, 

 and a])parently accoi'ding to the mode of heating, a iiigher temperature 

 giving more silvei- and sulphur dioxide. The first moietv of gas Avas 

 thus found to consist of four volumes of nitrogen to fi\'e of sul{»hur 

 dioxide, and the second moietv of two volumes of nitroo-en to thi-ee oï 



* May possibly have been already described l>y Berf:?lund in the Lunds univ. Arsk. 12. 



