on the Precipitation of Barium as /Sulphate. 401 











Series I. 

















Time be- 









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Ba(N0 3 ) 2 



BaS0 4 



terms of 



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found. 



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HN0 3 . 



volume 





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grm. 



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hours. 





cm 3 



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Having shown that free nitric acid even though present in 

 considerable amount has only a slight solvent influence upon 

 barium sulphate it seemed interesting to try the effect of the 

 combination of nitric and hydrochloric acids mixed in the pro- 

 portion to form aqua regia (3HC1 : !HlSr0 3 ). The experiments 



