140 COMBINATIONS OF AMMONIA WITH CARBONIC ACID. 



I may be allowed to add a few additional remarks on the che- 

 mical fonnulae in the last column. If the various salts of car- 

 bonic acid with ammonia be regarded as combinations of the 

 carbonate oxide of ammonium, with carbonate of ammonia and 

 the hydrate of carbonic acid, some of the salts will still contain 

 superfluous water. This is the case with the 5th, 7th, 8th, 10th, 

 11th, and 12th; yet it is possible, as was previously noticed, that 

 the latter salt may be prepared with 1 atom less of water, and 

 then it would not belong to this section. I am inclined to con- 

 sider this water as real water of crystallization ; I have, however, 

 not performed any experiments to ascertain whether it might be 

 removed without any change in the composition. With respect 

 to the view, that carbonate oxide of ammonium is partly com- 

 bined with carbonate of ammonia, partly with the hydrate of 

 carbonic acid, and partly with both together in the salts de- 

 scribed, this is founded on a hypothesis, upon which I lay but 

 little sti-ess, and which needs more confirmatory facts before it 

 can be adopted. In a memoir communicated many years ago to 

 the Annalen*, I endeavoured to show" that in numerous salts 

 ammonia acted quite the same part as the water of crystalliza- 

 tion, and that it might, as it were, replace it. It may, therefore, 

 be possible, that water, even when not existing as water of cry- 

 stallization and ammonia, both combined with carbonic acid, 

 might form bodies which might equally be replaced. This at 

 least appears to be the case in those combinations which these 

 bodies form with the carbonate oxide of ammonium. If we 

 admit this view, several of the ammoniacal salts described would 

 have, as was already noticed with respect to the hydrous neutral 

 carbonate and the bicarbonate, an identical composition. 



From a subsequent communication from M. Bauer, the arti- 

 ficially-prepared combination of carbonate of soda and carbonate 

 of lime stand in the same relation to water as the Gay-Lussite 

 which occurs in nature. 



* Poggendorff's Annalen, vol. xx. p. 1G3. 



