58 DIVERS AND HAGA. 



Jiiied with .sulphur trioxide coiiibines with the trioxide yieldino- two 

 products, one a hard vitreou« iiiatter replacing the lining of sulphur 

 trioxide, the other a loose flocculent deposit. Jacquelain got the saine 

 flocculent body when he mixed vapour ol" sulphur trioxide with dry 

 ammonia in excess. Rose found that both the flocculent and vitreous 

 matters when dissolved in watei" and evap(jrated vielded crNsta.ls of the 

 same substance, but that the vitreous matter was often acid through, 

 as he considered, imperfect action of the ammonia. The crystals from 

 solution he called jiarasulphataimiiuH : they are ikjw known to be diam- 

 monium imidosulphonate, and from what we ourselves have seen of 

 sublimed ammonium imidosulphonate, we have very little doubt of the 

 vitreous matter being the same salt, and of its occasional acid reaction 

 being due to its hydrolysis. The crystals are therefore formed from 

 three volumes of amnKjnia and twf) of sulphiu" trioxide. but Rose made 

 them out to have the same composition as the undissolved flocculent 

 mattei', and to be formed therefore from two volumes oi ammonia and 

 one of sulphur trioxide. He recognised, however, such differences in 

 their properties that he held them to be distinct bodies, and called the 

 flocculent matter siilphakumiiuH. Jacquehiin {»repared parasulphatam- 

 mon from the flocculent matter by two metliods. 1)oth without the use 

 (jf watei'. He found this matter to be variable in ccjmposition, and (jnc 

 of his methods of getting crystalline j)ure parasulphatammon from it. 

 was to fuse it in a current of ammonia, let it solidify, and then sto[> the 

 further entrance of ammonia before it cooled. His other method was 

 to expose the flocculent matter, tirst, over sulphuric acid in a vacuum 

 till it ceased to lose weight, and then to a moderate heat, which caused 

 a further loss. 



Having in a most careful manner proved the strange erroneous- 

 ness of Rose's analysis of parasulphatammon, Jacquelain himself made 

 a, n(j less strange misconstruction of the facts he had correctlv observed. 



