108 HEINRICH ROSE ON THE COMBINATIONS OF 



tral anhydrous carbonate of ammonia, on the contrary, loses, by 

 the action of the vapour of the anhydrous sulphuric acid, its 

 carbonic acid, without any effervescence, and is converted into 

 anhydrous sulphate of ammonia. - 



The neutral carbonate of ammonia may be prepared from the 

 common sesquicarbonate in various ways, but not in a dry state. 

 There is no way of obtaining it crystalUzed from a solution. The 

 solutions of all the combinations of ammonia with carbonic 

 acid, which contain more carbonic acid than the neutral salt, 

 lose, when heated, carbonic acid, and are converted into the neu- 

 tral combination ; while the solution of this latter, evaporated at 

 the common temperature, (in vacuum either over sulphuric acid 

 or hydrate of potash,) loses ammonia, and changes into super- 

 carbonates. 



When the solution of the sesqui- or bi-carbonate of ammonia 

 is boiled for a short time, it acquires the property of being thrown 

 down entirely by an excess of a solution of the chloride of ba- 

 rium, or the chloride of calcium ; so that pure ammonia produces 

 no precipitate in the liquid filtered from the carbonated earth, 

 nor even an opalescence. In the solution, therefore, there is a 

 neutral combination of carbonate of ammonia. If the boiUng is 

 continued, the salt volatilizes entirely from the solution. 



M. Hiinefeldt* has shown, that when solid sesquicarbonate is 

 subjected to distillation along with alcohol, on the boiling of 

 the alcohol the carbonic acid escapes as gas ; a portion of the 

 alcohol then passes over, upon which a sublimate of a solid salt 

 volatilizes with the remainder of the alcohol, at first adhering to 

 the neck of the retort, and finally passing into the receiver with 

 the vapours of the alcohol : this salt is the neutral carbonate of 

 ammonia. I have frequently repeated this experiment in various 

 ways, and convinced myself of the correctness of the fact. If 

 the sublimed salt is dissolved in water, the solution is com- 

 pletely precipitated by a solution of the chloride of barium or 

 the chloride of calcium in excess, and in such manner that no 

 milkiness is produced by an adcUtion of ammonia to the solution 

 filtered from the carbonated earth. 



It is, however, impossible to dry the neutral salt moistened 

 with alcohol without its changing in its composition and losing 

 tjome ammonia. When I di-ied it as quickly as possible by 



* Journal fiir pruldische Chemie, vol. vii, p. 25. 



