Effect of Temperature , Acidity, etc. 



4:01 



Table III. 



Showing the hydrogen sulphide obtained by heating natural and synthetic 

 iron disulphide to 600° in vacuo. 



Quantity of pyrite 



in the product Quantity of H 2 S Quantity of H 2 S 



Sulphide tested determined by the obtained in calculated in 



1 g. in all cases Stokes test. terms of BaS0 4 milligrams 



Joplin marcasite, 

 ground in water 



Joplin marcasite, 

 ground in water 



Joplin marcasite, 

 ground dry 



f Joplin marcasite, 



heated in 2<f 



H 2 S0 4 2 days at 200' 



Synthetic FeS 2 

 at 200° from 

 0-1$ HS a 4 , ground 

 in water 



Synthetic FeS 2 

 at 200° from 

 0-\fo H 2 S0 4 , ground 

 in water 



Synthetic FeS 2 

 at 200° from 

 lfo H 2 S0 4 , ground 

 in water 



Synthetic FeS 2 

 at 200° from 2f 

 H 2 S0 4 , ground 

 in water 



Synthetic FeS 2 

 at 200° from 2'5/o 

 H 2 S0 4 , ground 

 in water 



Synthetic FeS 2 

 at 200° from 2*5$ 

 H 2 S0 4 , ground 

 in water 



none 



none 



30-40^ 



45f 



45< 



S-5fc 



26fo 



26fo 



7*6 milligrams 



8-1 " 



00 



8-1 " 



12-2 " 



9-7 



5-7 " 



20-0 " 

 17-1 



16*2 " 



1-1 



1-2 



o-o 



1-2 

 1-8 



1-4 



0-8 



2-9 



2-5 



2-4 



for 2 b. in water and purified like the synthetic products for 

 the Stokes test, it gave off hydrogen sulphide on heating in 

 vacuo ; whereas the same mineral ground dry for 2 h. gave off 

 none. It is also certain that the water could not have come 

 f Ground in water before heating. 



