420 



AGRICULTURAL ANALYSIS 



evolution of nitric oxid takes place. In shaking, the apparatus 

 should be so held as to prevent the escape of the mercury from 

 the small tube i by keeping it closed with the finger or drawing 

 over it a rubber cap. 



After the evolution of the gas has ceased, the tube e, Fig. 29, 

 is brought into contact with ', (Fig. 30) and the two are joined 

 by a tight-fitting piece of rubber tubing in such a way as to ex- 

 clude any particle of air. The tube F, Fig. 30, is lifted and B 

 and C, Fig. 29, depressed. On carefully opening the cocks h and 

 b, and bringing i and e into union, the gas is passed from G into 

 A. When all the gasr'-ims entered A and the acid mixture from 



Pig. 30. Iunge's Analytic Apparatus. 



G has reached b, the latter is closed, and also h. The apparatus 

 G is disconnected and removed. The gas in A is then reduced to 

 normal conditions by manipulating the reduction tube, C, in the 

 manner already described. 



The gas in A is measured dry by reason of having been gen- 

 erated in presence of rather strong sulfuric acid. Consequently, 

 for this operation the adjustment of the volume' of gas in C 

 should be made in contact with a drop of strong sulfuric acid. 

 In order to make the readings, a quantity of material must be 



