50 DIVERS AXD HA^A. 



Rose disccwered in 1884 that the compounds of sulphur trioxide 

 with ammonia, his sulj)]iafammon and jxircLsidphatamiuoit, give, when 

 freshly dissolved in water, the reactions of a sulphate very incom- 

 pletely or not at all, and do not yield up all their nitrogen as ammonia 

 to chloroplatinic acid and other reagents. 



Jacquelain discovered the then unlikely fact that the stable com- 

 pound of sulphur trioxide and ammonia, liis sulphamide, is derived 

 from two molecules of the oxide and three of ammonia. 



Berglund determined the constitution of this stable compound to 

 be imidosulphonic, by ascertaining that it behaves ns an ordinary 

 ammonium salt only to the extent of two-thirds of its nitrogen. 



To Fremy is owing the discovery that hydrolysis of the main 

 product of the action of a nitrite upon a sulphite yields a salt, his 

 s'ldphaDiidate, now known to be an imidosulphonate ; and that this salt 

 exhibits the reactions of neither nitrite nor sulphite and can be so far 

 hydrolysed as to yield ammonia. 



He and, after him, Claus and Koch having attributed to this salt 

 a composition which allowed of its being written down as an addition- 

 compound of ammonia, lierglund proved them to have erred by 

 himself establishing the identity of P^remy's ])otassium sulphamidate, 

 Claus's disulplunnmonati', witli potassium imidosulphonate prepared 

 from ammonium imidosulphonate coming from chlorosulphonic acid 

 and ammonia. Mendeléelî" (al)s. in Ber. Cli. Ges., 3, «S72) had just 

 before suggested such a constitution as ])ossibly belonging to Fremy's 

 sulphami dates. In his Vrinc'qdcs of CJiciiiislnj, (18i)l), however, 

 apparently unaware of Berglund's results, he treats parasulphatam- 

 mon as being ammonium amidosulphonate. More recently, Raschig 

 showed that the properties of Fremy's salts are inconsistent with 

 Chius's views as to their being quinquevalent nitrogen compounds. 



Claus recognised the sulphonic constitution of these salts, while 



