ARRANGEMENT OF THE ELEMENTS IN COMPOUNDS. 



The application of this theory to the compounds of am- 

 monia with sulphuretted hydrogen and sulphur is particularly 

 felicitous. These compounds may be thus represented, and 

 placed in comparison with their potassium analogues, NH 4 

 being equivalent to K. 



Sulphuret of ammonium . . . NH 4 S . KS 



Hydrosulphuret of sulphuret of ammonium (bihy- 



drosulphuret of ammonia . . . NH 4 S, HS . KS, HS 



Tritosulphuret of ammonium . . . NH 4 S 3 . KS 3 



Pentasulphuret of ammonium . . . NH 4 S 3 . KS 5 



Ammonium is supposed to present itself in a tangible 

 form and in possession of metallic characters, in the for- 

 mation of what is called the ammomacal amalgam. When mer- 

 cury alloyed with one per cent of sodium is poured into a sa- 

 turated cold solution of sal ammoniac (chloride of ammonium), 

 it undergoes a prodigious increase of bulk, increasing sometimes 

 from one volume to two hundred volumes, without becoming 

 in the least degree vesicular, and acquires a butyraceous consis- 

 tence, while its metallic lustre is not impaired. A small addi- 

 tion is at the same time made to its weight, estimated at from 

 1 part in 2000 to 1 in 10,000, and which certainly consists 

 of ammonia and hydrogen in the proportions of ammonium. 

 The sodium, it is supposed, combines with the chlorine 

 of chloride of ammonium, and the liberated ammonium with 

 mercury, so that the metallic product is an amalgam of 

 ammonium. It speedily resolves itself again spontaneously 

 into running mercury, ammonia and hydrogen. But the change 

 which occurs to the mercury in this experiment is of a recon- 

 dite nature, and admits of, at least, one other hypothetical ex- 

 planation which is equally probable. After all, however, 

 neither isolation nor the metallic character is essential to 

 ammonium as an alkaline radical, other basyles being now 

 admitted, such as ethyle and benzoyle, which have no claim 

 to such characters.* 



Other classes of ammoniacal salts may be formed in which 

 the fourth atom of hydrogen in ammonium is replaced by a 

 metal of the magnesian family, and by copper in particular 

 which most resembles hydrogen. Thus anhydrous chloride of 

 copper absorbs an atom of ammonia with great avidity, which 



* Viewed in relation with the organic basyles, it might be termed ammanyle, 

 rather than ammonium. 



