AMMONIA WITH CARBONIC ACID. 115 



possessed a decided ammoniaeal odour, deliquesced when ex- 

 posed to the air, and, as he believed, contained more ammonia 

 than the known combinations. John Davy confirmed this ex- 

 periment, and adds that it is more volatile than the last, and 

 that probably it is hydrous carbonate of ammonia. I did not 

 find that the hydrous neutral salt deliquesced in the air ; but the 

 salt, it is true, becomes moist, and remains so if the distillation 

 is continued for any length of time, and water passes over. 



III. The Sesquicarbonate of Ammonia. 



This is the salt which occurs in commerce. I have analysed 

 it several times, and found that, if it had not effloresced at its 

 surface from the action of the atmosphere, and had not changed 

 into the bicarbonate, it generally had, but not always, the compo- 

 sition which R. Phillips has assigned to it. The analyses were 

 performed with quantities which had been obtained from various 

 manufactories. 



2-143 grm. of salt gave 3*530 grm. of metallic platina; I'llS 

 grm., however, of another quantity, 1*965 grm. of platina. The 

 first quantity answers to 28*66 per cent., and the last to 30*70 per 

 cent, of ammonia. The quantities of carbonic acid, which were 

 determined in the gaseous form by means of muriatic acid over 

 mercury, varied quite as much. 



0*607 grm. gave 155 cub. centim. ; 1*480 grm., 399*44 cub. 

 centim. ; and 1*419 grm. of the salt, 403 cub. centim. carbonic 

 acid gas. This answers to 50, 55, 53, 40, and 56*23 per cent, 

 carbonic acid in the salt. 



These differences are explained by the modes of preparing the 

 salt. When it has been prepared directly by subhmation from 

 carbonate of lime and sal-ammoniac, or from sulphate of ammonia, 

 then it is sesquicarbonate of ammonia. When, however, it has 

 been once more sublimed in the manufactory, probably in order 

 to purify it, it has changed into |-carbonate of ammonia, of 

 which we shall speak hereafter. 



The calculated composition of the sesquicarbonate, according 

 to the formula 3 C +2 NH^ -I- 2 H, is 



Ammonia 28*92 



Carbonic acid 55*91 



Water 15*17 



100*00 

 H 2 



