ON METALLIC SULPHURE-TS. J4.5 



Component parts of iron pyrites. 



Metallic iron 4^ 



Sulphur 55 



1 00. 

 Sulphuret of copper. 



Messrs. Lelievre and Gillet-Laumont, mine-cou-nsellors, Sulphuret d 

 leaving had the goodness e"ach to present me with a speci- copp^r* 

 men of sulphuret of copper, I shall proceed to give the re- 

 sults of my analysis of this mineral. 



1. Siberian sulphuret of copper from the collection of 

 Mr. Lelievre. Spec, gravity 5*22. 



Five grammes of this mineral treated with n-itromuriatic Treated with 

 acid assisted by heat were reduced to 0*51 of a gr. of sul- ^^"^^ ""^Sia' 

 phur nearly pure. Gakination left only 0*04 gr. of oxide, 

 which was completely redissolved. 



The solution precipitated by muriate of barytes let fall Precipitated by 

 4-01 gr. of sulphate, corresponding to 0-5() of a gr. of sul- ™""^^^^f b*- 

 phur. This brings the whole quantity of sulphur to 1'03 

 gr. The iron was separated from the copper by ammonia. 

 The precipitate, well washed and dried, weighed 0-08 of a gr. 



The brown oxide of copper precipitated by potash weighed 

 4'65gr., answering to 3*72 gr. of metallic copper. 



I convinced myself by various experiments, that the spe- No earth, lead^ 



cimen subjected to- analysis contained no earthy substance, "i^nganese, or 



•' ' antimony. 



lead, manganese, or antimony. The small quantity of iron a little oxide 

 eixiisting in it appeared to me even to be included in small of iron foreiga 

 fissures, in which its oxide is easy to be perceived : it cannot ^^ ^'* 

 therefore be considered as an essential part of the composi- 

 tion of sulphuret of copper. 

 The results of this analysis are 



Metallic copper 74.5 GompoHent 



Sulphur 20-5 f^"'- 



Oxide of iron 1 '5 



Loss 3'5. 



100- 



The experiments I made in the course of the analysis lead 



tne to think, that part of the loss fell on the copper. Not- 



^withstanding this however, the proportion of sulphtir to 



Vox. XXIf— Oct. 1 808, L copper 



