102 HEINRICH ROSE ON THE COMBINATIONS OF 



1. The Neutral Anhydrous Carbonate of Ammonia. 



It is well known that the neutral carbonate of ammonia is ob- 

 tained by mixing dry ammoniacal gas with carbonic acid gas, 

 and that both gases combine slowly, and only, (whichsoever of the 

 two may be present in excess) as Gay-Lussac* first discovered, 

 in the proportion of one volume of carbonic acid gas to two of 

 ammoniacal gas. The properties of the anhydrous carbonate of 

 ammonia obtained in this way are nevertheless almost unknown. 



Dr. John Davy f, who last experimented on the combinations of 

 ammonia with carbonic acid, confirmed the previous experiments 

 of Gay-Lussac, without however subjecting the combination to a 

 more accurate examination. He states that it possessed the 

 property of being decomposed without effervescence by a neutral 

 solution of chloride of calcium, and formed with it a neutral 

 fluid. 



I have only repeated the experiments of Gay-Lussac with the 

 intention of learning whether, with an excess of ammoniacal gas, 

 the two gases combined in the proportions above mentioned. 

 I conveyed the carbonic gas into an excess of ammoniacal gas, 

 and obtained the following results : 



1. 29'7 vol. carbonic acid gas, combined with 61 vol. of ammoniacal gas 



2. 24-9 49-75 



3. 201 38-1.5 



The small differences are easily explained, by what I have 

 on another occasion mentioned respecting the mixture of two 

 gases which combine to form a solid body J. The volume of the 

 absorbed carbonic acid gas in the first experiment is e^ddently 

 smaller on this account than it should be, because the carbonic 

 acid gas was mixed with too great an excess of ammoniacal gas ; in 

 the second this was less, and in the third experiment still less. 



Since the combination of ammonia with the carbonic acid gas 

 is formed very slowly, no vapour is observed when a glass rod 

 moistened mth ammonia is held over a carbonated alkah, from 

 which the carbonic acid is disengaged by sulphuric acid, as is 

 always the case when volatile acids, such as mimatic acid, sul- 

 phurous acid, nitric acid, acetic acid, &c. are disengaged from a 

 fluid by sulphuric acid. 



* Memoires de la Societe d'ArcueU, torn. ii. p. 211. 



•f- Edinburgh New P/iilosopfiical Journal, vol. xvi. p. 245. 



J Poggendorif's Annalen, vol. xlii. p. 417. 



