Specimens of Purple Copper Ore and Copper Pyrites. 281 



100-000 99-652 100-13 



The mineral analyzed by Hisinger is of unknown locality, 

 that of Plattner from the White Sea, and that of Bodemann 

 from Bristol in the United States. All these are evidently 

 of the same chemical constitution as the specimen above 

 analyzed, and may be represented by the formulae 7 Cug S 

 -f Fog S^, or by Cug S + Fcg S3. Their formulae give re- 

 spectively the following per-centage composition : — 



7 Cu, S + Fe3 S,. Cu, S + Fe, S3. 

 Sulphur, . 25-23 25-77 



Copper, . 63-17 63-37 



Iron. . 11-60 1086 



100-00 10000 



The last of these formulae is that assigned by Bodemann 

 to the mineral analyzed by him, but the first approximates 

 more nearly to the per-centage composition actually found. 



Although it is evident that one or other of these two for- 

 mulae will represent the mineral here analyzed, as well as 

 the three analyses above quoted, still it is impossible to re- 

 concile these results with many other analyses of this mine- 

 ral given by other chemists, as, for example, the following : — 



I. II. 



Sulphur, . 28-23 23-75 



Copper, . 56-76 61-07 



Iron, . 14-84 14*00 



Silica, . 000 0*50 



99-33 99-32 



The first of these analyses being by Plattner refers to a spe- 

 cimen from Cornwall in England, which was crystallized, 

 and could be represented by the formula 3 Cug S + Fcg S3, 

 as given by him. The latter analysis by Philipps, from 

 Killarney in Ireland, will be found to be nearly the formula 

 2 Cug S + Fe S. These two formulae give the following 

 per-centage results: — 



