AMMONIA WITH CARBONIC ACID. Ill 



was by the sublimation of a mixture of anhydrous sulphate of 

 ammonia and carbonate of soda. If every trace of moisture is 

 avoided, a product is obtained as pure as by the mixture of the 

 gases. 



The impossibility of combining the anhydrous neutral carbo- 

 nate in any way with the quantity of water which is requisite to 

 convert the ammonia into the oxide of ammonium is in so far a 

 very remarkable circumstance, as the carbonate of ammonia 

 dissolved in water exhibits quite the identical properties which 

 the carbonate of the oxide of ammonium would present, and, 

 moreover, does not differ essentially in its other relations from 

 other combinations of carbonic acid with ammonia, in which 

 the latter may be regarded as the oxide of ammonium. Berze- 

 lius's view of considering the ammoniacal salts, on account of 

 their water, as salts of the oxide of ammonium, is so plausible, 

 and has justly been adopted by so many chemists, that the 

 composition and properties of the anhydrous carbonate of am- 

 monia do not suffice to render this view less probable. It must, 

 therefore, be regarded as a body of a peculiar kind, belonging, 

 with respect to its composition, to a class with the anhydrous 

 combinations of ammonia with sulphuric acid and sulphurous 

 acid, which latter, however, essentially differ in their properties 

 from the carbonate of ammonia, in so far as these ammoniacal 

 salts vary considerably in their action upon re-agents from the 

 corresponding salts of the oxide of ammonium, and indicate in 

 the most evident manner the distinction between combinations 

 of ammonia and those of the oxide of ammonium. The most 

 important distinction which exists between the anhydrous neu- 

 tral carbonate and the hydrous combinations of ammonia with 

 carbonic acid, which contain more carbonic acid, is that the 

 former may be subUmed undecomposed, which is not the case 

 with the latter. 



It must be here mentioned that I have also prepared some 

 anhydrous combinations of ammonia with oxy-acids, which, 

 dissolved in water, did not differ, in their properties, from their 

 coiTesponding salts of the oxide of ammonium, and in this respect 

 are analogous to the carbonate of ammonia. 



II. The Neutral Hydrous Carbonate of Ammonia. 

 The experiments mentioned in the preceding section show 

 that it is not possible to combine the neutral anhydrous carbonate 



