94 



CHEMICAL ANALYSIS OF SOIL 



74. 



Total Carbonate. 



If the quantity of carbonate present in the soil is 

 large, its amount may be determined {a) by loss of 

 weight ; {U) by absorption. The use of the Schrotter 

 apparatus for the former method has already been 

 described. 



75. Method of A bsorption. 



The apparatus shown in Fig. i6 is employed. 

 The experimental flask A, of about 300 c.c. capacity, 

 is fitted with a dropping funnel containing the dilute 



Fig. 16. — Estimation of carbonates in soil by absorption. 



acid necessary for the decomposition, and with the 

 outlet tube a^ which is connected with a series of tubes 

 for purifying the COg previous to its absorption. The 

 U-tubes B and C are packed with anhydrous calcium 

 chloride. The tube D is filled with pumice stone, which 

 has been soaked in a saturated solution of copper 

 sulphate and dried at 200° to 300° C. This tube is 



