6 4 



The Estimation of Nitrogen 



[93 



a is an ordinary half-gallon oil can fitted with a good cork 

 pierced by two holes. Through one hole passes the straight 

 tube k, which reaches to within an inch of the bottom of the 

 can. Through the other passes the delivery tube m. This 

 arrangement serves as a boiler for supplying steam, b is a 

 6o-oz. flask fitted with an india-rubber stopper pierced by three 

 holes. The tube m passes through one of these down to the 

 bottom of the flask j the other two being occupied respectively 



Fig. 29. 



by the tap funnel s and the trap t. This trap is merely a 

 device for preventing caustic soda from being mechanically 

 carried over into the condenser. Its construction is sufficiently 

 apparent from fig. 30.  c is a condenser of the usual form, but 

 made of metal instead of glass, the inner tube being of block 



1 The trap may be left out if the tube leading from the flask B be con- 

 tinued straight upwards for a foot or so before it bends down to dip into 

 the condenser. 



