AMMONIA WITH CARBONIC ACID. 103 



To obtain the combination in great quantities, considerable 

 portions of" the dried gases were brought into contact, in large 

 vessels, which had been filled with dry air. The combination 

 adheres so firmly to the sides of the vessels, especially when 

 they have been artificially cooled externally, that it is frequently 

 possible to obtain it in no other way than by breaking them. 

 It is only when no external refrigeration has been appUed to the 

 vessels that a portion of the combination can be obtained in a 

 pulverulent state. I therefore subsequently caused the two 

 dried gases to pass through several glass tubes, which were kept 

 cool at their outer surface, in order to obtain larger quantities of 

 the neutral salt. These tubes were then cut, and the salt depo- 

 sited in them taken quickly out. On preparing the salt in this 

 way, it was observed that on the combination of the two gases a 

 very considerable increase in temperature takes place. 



If in the preparation of this combination the greatest care is 

 not taken to avoid every trace of moisture, which, with great 

 quantities, it is very frequently difficult to effect, small admix- 

 tures of the hydrous combinations of ammonia occur with the 

 anhydrous carbonate. 



1'3425 gramme of the neutral anhydrous carbonate, dissolved 

 in water, gave with a solution of chloride of barium 3 '3 21 grm. 

 of carbonate of barytes. The liquid filtered from it, treated with 

 ammonia, gave a slight precipitate, the weight of which was not 

 determined. 1*444 grm. of the combination, treated in the 

 manner pre\'iously described with muinatic acid, alcohol, chloride 

 of platina and asther, gave 3'461 grm. of heated metallic platina. 



The carbonate of barytes obtained corresponds to 55*45 per 

 cent, carbonic acid in the combination, and the quantity of pla- 

 tina to 41*69 per cent, ammonia. If we consider that a veiy small 

 quantity of the hydi'ous bicarbonate of ammonia was contained 

 in the combination, as would seem from a precipitate, although 

 an inconsiderable one, being produced in the solution precipi- 

 tated by chloride of barium and filtered, the compound formed 

 agrees with the calculated formula NH ^ + C, according to which 

 56*31 per cent, carbonic acid is combined in the salt with 43*69 

 per cent, ammonia. 



It results from this examination, that in the solution of the 

 anhydrous carbonate of ammonia, its constituents can be quan- 

 titatively separated by the same re-agents as in the case of the 

 Siolutions of the hydrous combinations of ammonia with carbonic 



