112 



E. J. LUND. 



c.c. .0098?? HC1 is perhaps largely due to error in weighing such a 

 small quantity as one milligram on the balances which were only 

 sensitive to about 1/20 mgm. Considering the small amounts 

 of CO 2 involved, the degree of accuracy obtainable is rather 

 striking; the amount of CO 2 apparently not recovered in the 

 above test being about 5 per cent, of the CO2 liberated from I 

 mgm. Na 2 CO 3 or about .01 c.c. CO 2 at N.T.P. In another 

 similar experiment using lots of I mgm. Na 2 COs about 5 per 

 cent, more CO 2 was recovered than was expected from i mgm. of 

 carbonate. This indicates that the error was perhaps largely 

 one due to weighing. In one test in which was used 2 mgm. of 

 carbonate all of the CO 2 was absorbed in less than 1^2 hours. 

 Still another similar test to determine the rate of absorption of 

 CO 2 from 5 mgm. of carbonate showed that at the end of fifteen 

 minutes over 60 per cent.-7o per cent, of all the CO 2 was absorbed, 

 and at the end of one hour all of the CO 2 was absorbed. To show 

 that within the limits of error in weighing, the CO 2 in 2, 3 and 5 

 milligrams of carbonate can be practically completely recovered 

 in relatively short periods of time by 15 c.c. weak solution of 

 Ba(OH) 2 the results in Table III. are given. 



TABLE III. 



The differences among the individual analyses were rather 

 larger in this test than in some of the others. One and one half 



