richards, McCaffrey*, and bisbee. — calcic oxalate. 



383 



hydrochloric acid to keep the calcic oxalate in solution. Subsequently 

 strong ammonia was poured very slowly into the liquid, with continual 

 stirring, until the solution contained an excess of ammonia. Methyl 

 orange was found to assist materially the exact neutralization. 



Precipitation by Concentrated Ammonia. 



Some calcium was found in the mother liquors upon the addition of 

 more amnionic oxalate ; but this is included above. Evidently no mate- 

 rial <*ain in accuracy is effected in this series, and the reason is not hard 

 to find. The ammonia was so strong that it caused instant neutralization 

 of the acid in its neighborhood ; and hence the idea of the method was 

 defeated, for the design was to effect a gradual neutralization, giving 

 time for the supersaturated calcic oxalate to separate. 



In the next series twice as much oxalic acid was used, but the am- 

 monia added to effect the precipitation was far less concentrated. 



Precipitation by Dilute Ammonia. 



