DETERMINATION OF CARBON DIOXIDE 



291 



about 125 mgm. of CO2 and leave a safe excess of Ba(0H)2. 

 Should the quantity of CO2 to be absorbed exceed this amount, 

 two charges from the pipette must be transferred to the tower; 

 if less, one charge is employed, and about an equal volume of 

 C02-free water. The tubulure of the suction flask is then con- 



Fig. 1 



nected to the respiration chamber, a minimum of rubber tubing 

 being exposed to the current of gases. In the bulk-grain respira- 

 tion studies, an 18 in. calcium chloride tower, A, has been employed 

 as a respiration chamber. The latter is connected at the top to 

 a gas washing de\dce charged with 50% KOH solution for remov- 



