56 § 47. BASES AND ACIDS WITH KEAGENTS. 



h. Ammonia may also be determined by expulsion 

 from the mixture containing it by a strong base, and col- 

 lecting the product in a known quantity of standard acid. 

 [Schlossing^s process.) The solution to be examined, 

 which should not be more than 35 c.c. in bulk, nor con- 

 tain more than 0.3 grm. of ammonia, is put in a shallow 

 vessel, A, about 5 cm. in diameter, which, in its turn, is 

 put on a plate about 10 cm. in diameter, the bottom of 

 which is covered with mercury. Put 10 c.c. of the nor- 

 mal sulphuric acid in another, and rather smaller, shallow 

 vessel, B, that is supported over A by a glass triangle ; 

 then put about 10 c.c. of milk of lime or sodic hydrate in 

 A with the ammoniacal solution, by means of a pipette, 

 and finally invert a bell-jar or a weighted beaker over 

 the whole, and be sure that its rim is completely immers- 

 ed in the mercury. 



After 48 hours, the ammonia will usually be entirely 

 expelled from the substance, and absorbed by the acid ; 

 in the analysis of animal and vegetable liquids, Schulze 

 found that three or four days were required, but that after 

 the expiration of that time the ammonia was completely 

 liberated. To test the matter, lift the edge of the bell- 

 jar or beaker, or take out the stopper of the tubulure, if 

 the bell-jar has such an appendage, and introduce a piece 

 of moistened red litmus-paper ; this should retain its red 

 color even if left for a considerable time in the jar. 



If the operation is finished, titrate the acid in the vessel 

 B, with the standard solution of soda ; the difierence be- 

 tween the number of cubic centimetres of acid put into 

 B in the beginning, and the number of cubic centimetres 

 of soda solution required to neutralize what acid remains 

 free, multiplied into 0.017 grm. will give the amount of 

 ammonia (NHJ in the substance analyzed— or, multiplied 

 into 0.026 grm. will give the amount of amnionic oxide 

 (NH.),0. 



If albuminoids are present in the substance examined. 



