Determination of Pyrite and Marcasite. 



391 



Fig. 7. 



60 



50 



40 



30 



20 



10 









































j ] 







































/, 



s 





































A? 





































y< 



































,<ti 



j? 







































































^ 



^ 



i*s' 































































Z^ 





"V 























































































































































10 



20 



30 40 50 60 



Percentage of pyrite 



70 



80 



90 



100 



Fig. 7. Curves showing sulphur oxidized in pyrite-marcasite mixtures by 

 a standard ferric solution. 1,1. Curve for purest natural pyrite and mar- 

 casite. 2, 2. Curve for the synthetic minerals. 



Fig. 8. 



■o 60 

 o 



CO 











































o 



a. 







































/( 



i 





































/■ 







3 



to 



3 40 



9 



















































































g 30 

































































^S 



» 

















f 80 



w C 











































> 



C 



i r 







































tt) 



hi) io 



CO 



c 



















































































O 



o 











































10 



20 



30 



40 50 60 



Percentage of pyrite 



70 



80 



90 



100 



Fig. 8. Curve showing sulphur oxidized in pyrite-marcasite mixtures by 

 a standard ferric solution. Stokes' results. The curve is a true hyperbola. 



