AMMONIA WITH CARBONIC ACID. 109 



means of bibulous paper, and then precipitated the sohition of 

 the dried salt by chloride of barium, I obtained from 1*042 grm. 

 of the salt only 1*714 grm. of carbonate of barytes, which only 

 answers to 36*87 per cent, carbonic acid in the salt. When, 

 however, some ammonia was added to the filtered liquid, and the 

 precipitate formed protected from the action of the air, I ob- 

 tained 0*688 grm. carbonate of barytes, corresponding to 14*80 

 per cent, of carbonic acid in the salt. 



I then attempted to dry the neutral salt, by placing it immedi- 

 ately in vacuo over sulphuric acid. The salt, it is true, became 

 dry, but was no longer perfectly neutral, for its solution gave, 

 after precipitation by the cliloride of barium, a precipitate with 

 ammonia. It is, nevertheless, the best method of drying the 

 salt without its composition being considerably affected. 



When I attempted to desiccate the salt moistened by alcohol 

 over a considerable quantity of the hydrate of potash in vacuo, 

 it remained moist although I kept it for more than a week under 

 the air pump. The hydrate of potash became, it is true, carbo- 

 nate at its surface, but a great quantity of ammonia was evolved 

 in the gaseous form during the pumping. 



The moist salt was then placed in a basin filled with fused 

 chloride of calcium, and this again put into a larger basin 

 containing hydrate of potash, and the whole then quickly placed 

 in a vacuum. The chloride of calcium became covered with car- 

 bonate of ammonia ; the remaining portion of the salt was dry, 

 but after desiccation was no longer neutral. 



I obtained a similar result when I employed quick lime in- 

 stead of the hydrate of potash. When I brought this, as was 

 the case with chloride of calcium, warm into the vacuum with 

 the moist salt, the greater portion of it volatilized and deposited 

 itself on the chloride of calcium ; the small quantity of the salt 

 remaining was not neutral. 



I then placed the moist salt with another combination of chlo- 

 rine of easy solubility in alcohol in vacuo. I chose for this 

 piu*pose pulverized bichloride of mercury. The carbonate of 

 ammonia remained moist, but the chloride of mercury attracted 

 some of it, and did not dissolve entirely in water, the solution 

 being opalescent. I obtained a remarkable result when I placed 

 the moist salt under the air pump with quick lime and the ace- 

 tate of lead. The carbonate of ammonia volatilized sooner than 

 the alcohol with which it was moistened; it combined with the ace- 



