Sept. lo, 1917 



Formation of "Black Alkali" 



553 



nounced. When oxalic acid is used, so that an insoluble salt of lime is 

 formed, there is a pronounced tendency for the curves to s\ving toward 

 the axis of ordinates. 



The system, sodium nitrate-calcium carbonate, was then titrated out 

 with nitric acid and the systems, sodium chlorid-calcium carbonate and 



Fig , -Graphs showing the sodium carbonate formed by reaction of calciiun carbonate (solid phase 

 represents the total sodium carbonate neutralized up to and mcludmg that titration. 



sodium sulphate-calcium carbonate, were titrated out in the same way 

 with hydrochloric acid and sulphuric acid, respectively. These results 

 are given in Tables XIII, XIV. and XV, and the curves for the hydro- 

 chloric and sulphuric acid titrations are shown on figures 6 and 7. 



