138 COMBINATIONS OF AMMONIA WITH CARBONIC ACID. 



is only the |- carbonate which loses a portion of the carbonic 

 acid in its solid state ; the other combinations, on the contrary, 

 undergo at the ordinary temperature quite a reverse decomposi- 

 tion ; they have a tendency to evolve partly ammonia, partly an- 

 hydrous carbonate, which have just the same odour as pure am- 

 monia. When, therefore, the recently-prepared acid salts do 

 not smell of ammonia, it nevertheless arises when they have 

 been kept for some time in a well-closed vessel, if this be opened. 

 Even the bicarbonate forms no exception to this ; and this perhaps 

 seems to indicate that it has a tendency to pass into the ^ car- 

 bonate. The solution of the carbonates of ammonia have a ten- 

 dency, at the common temperature, to smell of ammonia. 



With an increased temperature, the solutions of the carbo- 

 nates, as well as they themselves, the carbonate naturally ex- 

 cepted, evolve on the contrary carbonic acid. The solutions of 

 all the carbonates are converted by boiling into neutral salt, 

 and the solid salts lose a portion of the acid, and produce pai'tly 

 neutral, and partly less acid salts. 



I think it will be advantageous to enumerate, in a table at the 

 end of this memoir, the chemical formulae of the combinations 

 examined according to the various ^^ews which may be enter- 

 tained with regard to their composition, so that they may easily 

 be compared one with another. 



