314 Gooch and Hill — Purification oj Barium Sulphate. 









Table III 















Results reduced to 50 grm. 











of solution 









BaS0 4 

 found 



BaS0 4 

 found 





_^_ 







Wt. of 



BaS0 4 



BaS0 4 



BaS0 4 





BaCl 2 sol. 



before 



after 



before 



after 



by 





used 



treatm't 



treatrn't 



treatm't 



treatm't 



theory 



Error 



grm. 



grm. 



grm. 



grm. 



grm. 



grm. 



grm. 



50*281 



0-4767 



0-4766 



0-4740 



0-4739 



0-4737 



+ 0-0002 



50*348 



0-4784 



0-4771 



0-4751 



0-4738 



0-4737 



+ 0-0001 



50-199 



0-4764 



0-4754 



0-4745 



0-4735 



0-4737 



— 0-0002 



50-293 



0-4786 



0-4765 



0-4758 



0-4737 



0-4737 



o-oooo 



onto a filter-paper and washed thoroughly to remove the potas- 

 sium sulphate. The filter was dried and ignited in the cru- 

 cible, and the crucible and contents brought to constant weight. 

 Table IV gives the results of this series. Correction has been 

 made for the weight of the ash (0*0001 grm.) of the second 

 filter-paper, that of the first paper having been dissolved, pre- 

 sumably, by the treatment with sulphuric acid. 









Table IV. 













Results reduced to 50 grm. 













of solution 









BaS0 4 

 found 



BaS0 4 

 found 





A 







Wt. of 



BaS0 4 



BaS0 4 



BaS0 4 





BaCl 2 sol. 



before 



after 



before 



after 



by 





used. 



treatm't 



treatm't 



treatm't 



treatm't 



theory 



Error 



grm 



grm. 



grm. 



grm. 



grm. 



grm. 



grm 



50-262 



0-4814 



0-4749 



0-4789 



0-4724 



0*4737 



— 0-0013 



50-171 



0-4870 



0-4772 



0-4854 



0'4756 



0-4737 



+ 0-0019 



50-281 



0-4804 



0-4759 



0-4777 



0-4732 



0-4737 



-0-0005 



50-285 



0-4838 



0-4762 



0-4810 



0-4735 



0-4737 



-0-0002 



50-330 



0-4805 



0-4755 



4774 



0-4724 



0-4737 



-0-0013 



50-320 



0-4818 



0-4766 



0-4787 



0-4736 



0-4737 



—o-oooi 



50-278 



0-4813 



0-4765 



0-4786 



0-4738 



0-4737 



+ 0-0001 



50-301 



0-4804 



0-4751 



0-4775 



0-4723 



0-4737 



-0-0014* 



50-274 



0-4797 



0-4762 



0-4771 



0-4736 



04737 



— 0-0001 



50-235 



0-4790 



0-4753 



0-4768 



0-4731 



0-4737 



— 0-0006 



Av. 0-4789 0*4733 

 * A slight loss by creeping was expected in this experiment. 



This investigation shows that the evaporation can be carried 

 out successfully with the use of the blast lamp and platinum 

 gauze as a substitute for the Hempel burner, and that, although 

 the accuracy of the results is not as great as could be wished, 

 yet, where alkali salts are present, this method of purification 

 reduces the otherwise very large error to a value at most not 

 more than one or two milligrams for half a gram of barium 

 sulphate. 



