ON METALLIC SULPHURETS. J[4y 



1st analysis. Five grammes of this mineral, powdered, Treated with 

 and treated with nitromuriatic acid, were very easily attack- ^^^^ ^''^^^' 

 ed by it. The residuum, weighing 1*13 gr., was reduced 

 to 0.08 of a gr. by calcination ; and an addition of fresh acid 

 left only 0*04 of a gr. of quartzose gangue. 



Muriate of barytes threw down from the solution a preci- Preclpifatcd 

 pitate of Sulphate weighing 5-5 gr., corresponding to 077 ^^ mu^^iieof 

 of a gr. of sulphur. This quantity, added to that ah-eady 

 formed, gives 1*82 gr, for the whole of the sulphur it con- 

 tained. The copper was precipitated by sulphuretted hidro- ^^^ then by^ 

 gen, redissolved, and precipitated afresh by caustic potash, hidrot^en. 

 The brown oxide obtained weighed 1"88 gr., and contained 

 nearly 1*5 gr. of metal. 



The potash had dissolved about 0-0,5 of a gr. of oxide of 

 zinc. The red oxide of iron weighed 2*26 gr., correspond- 

 ing to 1"53 of metallic iron. 



Results. 



Sulphur 36*5 Component 



Copper , 30 parts. 



Metallic iron 31 



Oxide of zinc 1 



Gangue 1 



99-5 



2d analysis. The same substance was treated with nitric Treated with 



• 1 • i. J u V, i nilric acid. 



acid assisted by heat. 



First residuum, 2*35 gr. reduced to 1*86 gr. by calcina- Residuum cal- 

 tion. The nitromuriatic acid left of this only 0'23 of a gr., ?rm*ed with 

 containing only 0*04 of a gr. of gangue* aqua regia. 



The weight of the sulphur separated from these residuums Precipitated by- 

 was 0*93 of a gr. The solution gave a precipitate of 5*91 ™""at^ °^ 

 of sulphate of barytes, containing 0'82 of a gr. of sulphur, 

 and making the whole amount to 1*75 gr. 



The copper was dissolved by ammonia, and the oxide of Copper dissolv* 

 iron separated from it by several operations. The oxide of ^j^ aiidiroa 

 copper precipitated by potash weighed 1*9 gr,, answering to separated; 

 1'52 gr. of the metal. 



The red oxide of iron weighed 2*47 gr., and contained 

 166 gr. of pure iron. 



I likewise found traces of zinc, 



L 2 Result. 



