70 THE ROYAL SOCIETY OF CANADA 
The presence of both ammonium nitrate and ammonium chloride 
appreciably diminishes the solubility of aluminium hydroxide in 
ammonium hydroxide solutions. In the case of a solution that is 
4 normal as regards ammonia the amount of aluminium hydroxide 
dissolved in 100 c.c. of solution is reduced from 0-700 grams to 0-050 
grams. The presence of potassium nitrate on the other hand consider- 
ably increases the solubility. This fact should receive more considera- 
tion in the quantitative estimation of aluminium as for instance in 
such substances as the feldspars. 
University of British Columbia 
Syracuse University. 
