404 



AGRICULTURAL ANALYSIS 



ing to some authorities, very exact and reliable results. 42 The 

 extract, representing 500 grams of the fine soil, is reduced by evap- 

 oration to loo cubic centimeters and placed in a glass flask, A 

 (Fig. 23), of 500 cubic centimeters capacity. The flask is closed 

 with a rubber stopper, carrying two bent glass tubes which pass 

 through it. The tube a b c is drawn out into a point at a and 

 reaches about two centimeters below the surface of the rubber 

 stopper. The tube e f g passes just to the lower surface of the 



Fig. 23. Schulze-Tiemann's Nitric Acid Apparatus. 



rubber stopper. The two tubes mentioned are connected, by 

 means of rubber tubes and pinch-cocks, with the tubes d and h. 

 The pinch-cocks at c and g must be capable of closing the tubes 

 air-tight. The end of the tube g h passes into a crystallizing 

 dish, B, and is bent upward to a point passing two to three cen- 

 timeters into the measuring tube C. The point within the tube 

 is covered with a piece of rubber tubing. The measuring tube C 

 is divided into tenths of a cubic centimeter, and together with 

 the crystallizing dish, B, is filled with a 10 per cent, solution of 



42 Zeitschrift fur analytische Chemie, 1870, 9 : 24, 401. 

 Die landwirtschaftlichen Versuchs-Stationen, 1867, 9 : 9. 

 Berichte der deutschen chemischen Gesellschaft, 1873, 6 : 1038. 



