EicHARDS, McCaffrey, and bisbee. — calcic oxalate. 389 



FiGUKE I. Apparatus fok Filtering. 



A is tlie inverted filter, clad four-fold with filter paper. B is the collecting 

 flask, which fills only when C is open and D closed. E serves to retain the re- 

 jected liquid. 



It 18 not certain that these solutions were wholly saturated ; but the 

 difference in concentration between these and the earlier solutions, which 

 had been digested during much less time, made it highly probable that 

 any error from this cause would be less than the necessary errors of 

 titration. Hence no further determinations were made. 



After these determinations were finished, Kohlrausch and Rose's * 

 determinations by means of electrical conductivity at lower temperatures 

 were consulted, and were found to furnish agreeable confirmation of thes^e 

 independently obtained results. At 18° Kohlrausch and Rose's figure 

 was 5.9 milligrams per litre, while our extrapolated value is 0.0 milli- 

 grams ; and at 40° the respective figures are 8.0 and 8.4 milligrams. 

 Our slightly larger values may be due to the fact that we determined all 

 the calcic oxalate in solution, while Kohlrausch and Rose measured only 

 that part which is dissociated. According to the table up(jn page 200 



* Zeitschr. fur pliys. Chem.. 12. 23i (18'J0). 



