§ 47. AMMONIUM. 57 



it is better to use freshly ignited magnesia, instead of milk 

 of lime, to set free the ammonia, so as to avoid the forma- 

 tion of the compound out of a portion of the albuminous 

 matters ( Yogel). 



c. When the substance does not contain, besides am- 

 monia, nitrogenous organic matter that would yield 

 more ammonia on being heated with an alkali, the de- 

 termination may be more expeditiously performed as fol- 

 lows. 



Weigh the substance out in a small tube about 10 mm. 

 in diameter and 5 cm. long, put it in a small flask, A, 

 containing a moderately concentrated solution of sodic 

 hydrate which has been previously boiled for a consider- 

 able time to expel all traces of ammonia, and allowed to 

 cool again. Freshly ignited magnesia is sometimes used 

 in the place of the alkali. Put the flask in an inclined 

 position on the wire gauze over the lamp, and connect it 

 quickly with the tube of a small cooling apparatus ; con- 

 nect the other end of this tube by a good cork with a 

 tubulated receiver, B^ through the tubulure of which 

 passes another small tube that is bent twice and carried 

 to the bottom of a small flask, C. Put into the receiver, 

 j5, the larger portion of 50 c.c. of standard sulphuric acid 

 and tlie remainder in the flask C, and color the acid in 

 both vessels with a little cochineal; neither tube that 

 passes into JS should dip into the liquid contained in it. 

 Be sure, now, that the apparatus is tight throughout, boil 

 the contents of the flask A gently, and continue the 

 boiling for a little while after the drops of condensed 

 liquid as they fall into the receiver have ceased to change 

 the color of the acid as they come in contact with it. 

 Then remove the lamp, and allow the contents of the 

 flask (7 to flow back into B ; rinse C several times with 

 cold water, and allow these rinsins'S to flow into B also ; 

 finally disconnect the receiver B from the rest of the 

 apparatus, transfer its contents to a beaker without any 

 3* 



