HYDROGEN AND NITROGEN. 407 



obtained in a separate state, but always in combination with 

 another mercurial salt. The idea was thrown out by Dumas, 

 that the explosive compounds of nitrogen might contain ami- 

 dogen, and the same view has been applied to the fulminating 

 compounds produced by the action of ammonia upon the oxides 

 of silver and gold ; but these views have not yet been fully 

 verified by analysis. 



Potassium, heated in ammoniacal gas, N H 3 , disengages 

 hydrogen, as when it acts upon water. If ammonia were then 

 simply reduced to the state of amidogen, 4 volumes of the for- 

 mer should be decomposed to evolve 2 volumes of hydrogen ; 

 but in the numerous experiments of Gay-Lussac and Thenard, 

 never more than 3| volumes of ammonia were required to fur- 

 nish 2 volumes of hydrogen, and consequently a small portion 

 of the hydrogen must be furnished by the decomposition of 

 amidogen itself. The compound of potassium, which is a fusible 

 solid matter of an olive-green colour, likewise contains unde- 

 composed ammonia. The basis of it is, probably, a compound 

 of potassium and amidogen, but its constitution is very pro- 

 blematical. Ever since the formation of this compound, by 

 Davy and the chemists named above, the existence of such a 

 body as amidogen has been a floating speculation among che- 

 mists. But it was first fixed and distinctly enunciated by 

 Dumas, in his theory of the amides, in reference to a class of 

 compounds of which he is the discoverer. 



Ojcamide, N H 2 ,C 2 O 2 . When oxalate of ammonia is decom- 

 posed by heat, a white insoluble sublimate is obtained, which 

 was termed oxamide by Dumas, and viewed as a combination of 

 amidogen and carbonic oxide, N H 2 ,C 2 O 2 ; being formed by the 

 abstraction of the elements of two atoms of water from oxalate 

 of ammonia, of which the formula is N H 4 O, C 2 O 3 . When 

 oxamide is boiled with an alkali or with an acid, the two atoms 

 of water are again assumed, and oxalic acid with ammonia repro- 

 duced. Similar amides may be formed from other organic acids. 



Sulphamide, N H 2 , S O 2 . This is a compound exactly analo- 

 gous to oxamide, containing the radical sulphurous acid, S O 2 , 

 instead of C 2 O 2 , in combination with amidogen. Sulphamide 

 was formed, by Regnault, by the action of dry ammonia upon 

 chlorosulphuric acid, when 2 equivalents of ammonia and 1 of 

 chlorosulphuric acid become sulphamide and hydrochlorate of 

 ammonia : 



