48 F. S. Havens — Further Separations of Aluminum, etc. 



In determining the copper in the acid filtrate it was found 

 advantageous to weigh as the oxide, but to arrive at that condi- 

 tion through the sulphate rather than through the nitrate (which 

 was the transition salt in the case of zinc), as this process can be 

 carried on safely in platinum. 



In Table II (exps. 10 to 13) are given results of experiments in 

 which the aluminum was determined as previously described 

 by precipitation as the hydrous chloride and conversion to the 

 oxide, the acid filtrate was evaporated in platinum and the 

 copper determined by treating the residue with a few drops of 

 strong sulphuric acid, heating gently to drive off the excess of 

 sulphuric acid, and then igniting the sulphate to the oxide at 

 a red heat. That the copper sulphate is converted to the 

 oxide by ignition at a red heat over a Bunsen burner is 

 shown in experiments (7) to (9) of Table II. 



In conclusion the author wishes to thank Professor Gooch, 

 under whose direction this work has been carried on, for his 

 kind suggestions and advice. 



