'IMIDOSULPHONATES. 95 



•Hid then drained and dried on a tile. An incrustation (washed in 

 situ) was also analysed. The results were : — 



Argentuiii disodiuni imidosnlphonate. — This salt, which occurs as 

 crystalline fibres, is the most soluble of the three salts, but is still 

 only s{)aringiy so. It is gradually and visibly decomposed by water, 

 the change consisting apparently, partly in the formation of silver 

 hydroxide and hydrogen disodium imidosulphonate, partly in resolu- 

 tion into trisodium salt and the diargentum sodium salt. Although 

 readily produced it is, therefore, difficult to get pure. It retains a 

 very little water, as usual, and behaves when lieated almost like the 

 preceding salt. For analysis it was pressed froni its mother-liquor on 

 a calico filter, and then between ])orous tiles. In preparino- it the 

 sodium salt was added to a little less than one-third of its equivalent 

 of silver nitrate, and the ndxture agitated in order to redissolve the 

 white precipitate of silver salt first thrown down before the fibrous 

 crystals began to form. Analysis gave — 



Ag-XasNlSOg).^ a h c 



Sodium 14-02 14-75 — — 13-81 



Silver 32-93 33-07 33-49 33-50 33-49 



Sulphur 19-51 19-18 19-52 — 



Nitrogen 4-27 — — 4-29 — 



Double mcrcurtj iinidosulphonates. 



Single mercury imidosulphonates seem to be inca])able of ex- 

 istence. 



