THE ROYAL SOCIETY OF CANADA 



As postassium salts are usually present when aluminium hydroxide 

 is precipitated it seemed worth while to make some estimations of 

 the solubility in solutions containing potassium nitrate. The results 

 are set forth in Table III. 



Table III. 



These values show that the presence of potassium nitrate increases 

 the solubility very appreciably. This fact should receive more attention 

 in the quantitative estimation of aluminium. 



In conclusion we would emphasize this point, which is established 

 by the above experiments, that in precipitating aluminium as hydroxide 

 only a small excess of ammonium hydroxide should be added, and 

 ammonium nitrate solution of approximately 10% concentration 

 should be used in washing. 



University of British Columbia. 

 Syracuse University. 



