107] 



Nitrogen in Nitrates 



71 



tap funnel by which the liquid may be introduced into a. c is 

 a trap joint which prevents any of the solution from getting 

 into the side tube d. The tube d, by which the gas is to 

 escape, bends twice at angles of 135 , and is at least 36 inches 

 in length from the second bend, G, to the lower outlet. The 

 end n is recurved into a hook, so that the gas may pass into 

 the measuring tube, k, which stands in a trough of mercury, f. 



Fig. 3 



107. The Experiment. — Fix the tap funnel firmly in the 

 clip of a retort stand, in the position shown in the figure, so 

 that the side tube may fall over the side of the bench. Place 

 the mercury trough beneath the outlet n. Fix the flask a in 

 position, and the apparatus is ready for work. 



Weigh out about 1 gram of pure KN0 3 and dissolve in a 

 ioo-c.c. flask, as directed in paragraph 103. Measure out 20 c.c. 



