Richards, McCaffrey, and bisbee. — calcic oxalate. 393 



stand for four hours. The precipitated calcic oxalate should be thoroughly 

 washed with water containing amnionic oxalate. The filtrate will con- 

 tain all but about 0.1 or 0.2 per cent of the magnesium, and the precipi- 

 tate will contain all but about the same proportion of the calcium. 



7. The precipitate, having been formed slowly from a solution in 

 which it was somewhat soluble, is distinctly crystalline and far more 

 easily handled than if it had been suddenly precipitated. This is a 

 general effect, which might render service in other cases. 



Cambridge, Mass. 

 October, 1897, to February, 1901. 



