106 HEINRICH ROSE ON THE COMBINATIONS OF 



apparently very uncertain way, by keeping the salt for a long 

 time in contact with a measured volume of atmospheric air and 

 leaving it to evaporate in it ; he then treated the few cubic cen- 

 timetres of the mixture alternately with diy oxalic acid and with 

 potash, and thus obtained the volume of the ammonia and of 

 the carbonic acid*. 



Although the solution of the anhydrous carbonate of ammonia 

 does not act differently towards the re-agents from the hydrous 

 combinations of ammonia with carbonic acid, yet the combina- 

 tion, in its solid state, is distinguished on account of the absence 

 of water, by its action upon several substances, from the sesqui- 

 carbonate of ammonia. 



If dry muriatic gas is passed over the anhydrous carbonate of 

 ammonia, no action is perceptible in the cold, even when the gas 

 is left for a long time in contact wdth the salt. But if, during the 

 passing, the ammoniacal carbonate is heated at one spot only for 

 a moment, it decomposes there, and the heat gradually diffuses 

 itself through the whole combination ; and when it ceases, there 

 is no longer any carbonic acid combined with the ammonia, 

 and it has changed, naturally, without any disengagement of 

 water, into hydrochlorate of ammonia. The common sesquicar- 

 bonate of ammonia is decomposed, even in the cold, by muriatic 

 gas, Avith disengagement of heat. Water is formed by a slow 

 disengagement of the carbonic acid at the upper surface of the 

 glass sphere in which the mixture is contained. 



The anhydrous carbonate of ammonia is at first not at all af- 

 fected by gaseous chlorine ; after an action of several days only 

 does it gradually change, without any formation of water, into 

 muriate of ammonia, in which case carbonic acid and nitrogen 

 gas must necessarily escape. No formation of chloride of nitro- 

 gen takes place. The common sesquicarbonate of ammonia gra- 

 dually changes, with perceptible disengagement of water, into the 

 muriate of ammonia. If the salt is employed in pieces, they de- 

 compose very slowly, and, when taken out of the apparatus, ef- 

 fervesce with acids. Even in this case no production of chloride 

 of nitrogen could be observed; however, the experiment was not 

 continued until the salt had completely decomposed. The ex- 

 ternal portion of the salt, and the fine powder, had become per- 

 fectly converted into muriate of ammonia, without having indi- 



* Annalcs de Chimie el de Physique, vol. Ixviii. p. 434. 



