76 



DIVERS AND HAGÀ. 



Hydrogen sodium ammonium imidosidplionate nitrate. 



On dissolving trisodium imidosiilphonate and then its equivalent 

 of annncjuium nitrate (three molecules) in half their combined weig'ht 

 of hot water in ;i- closed nearly full vessel, a cold solution is obtained, 

 which sometimes remains unchanged, super-saturated, sometimes 

 s!(3wly deposits the trisodium salt again of the ordinary form, but in 

 thicker, crystals than Usual. The attempt to redissolve the crystals 

 by dipping the vessel in liof water readily succeeds l)ut is generally 

 attended with the copious separation of some white «jpaque salt 

 (sodium ammonium imidosulphonate?). On the vessel being left for 

 some days in a cold place, with occasional agitation, the trisodium salt 

 re-forms in crystals, and the opaque salt redissolves. When proceeding 

 differently, the fresh mixed solution of the trisodium salt and am- 

 monium nitrate in half their weight of water is placed on the steam 

 bath in an open glass capsule, anunonia freely escapes, and soon groups 

 of small prisms form, evidently in consequence of the loss of ammonia 

 by the solution and not its mere evaporation, for the addition of some 

 water has little effect up<jn tlie quantity of these crystals. The crystals 

 could not be separated i'rom their highly concentrated mother-liquor in 

 a: state lit for trustworthy analysis, Ijut we are pretty confident of their 

 being tlie salt now to be described. 



A well-crystallised d<nil)le salt of definite composition is ol)tainable 

 by evaporating a soluti(jn of trisodium imidosulplionate Avith a.t least 

 its equivalent of ammonium nitrate, until the liquor is nearly neutral, 

 then adding water to redissolve any crystals which have formed, and 

 leaving the product to cool sl(jwly. Through(3ut, care must be taken 

 that the liquor does not 1)ecome acid during evaporation, by adding if 

 necessary a drop or two of ammonia. Small flat, thick prisms are 



