84 Mr. R, Phillips on the [Feb. 



By Mr. Chenevix*s analysis, native sulphuret of copper consists of 



Sulphur 19 



Copper 81 



Too 



According to Dr. Thomson, hydrogen being 1, sulphur is 16, 

 iron 28, and copper 64 ; and sulphuret of copper is composed of 



One atom of sulphur 16 



One atom of copper 64 



"80 



These proportions it will be observed agree almost precisely 

 with those quoted from Chenevix. According to Mr. Hatchett, 

 magnetic pyrites, or the protosulphuret of iron, is composed of 



Sulphur 16-06 



Iron 27-94 



44-00 



This determination agrees also very nearly with Dr. Thomson's 

 numbers, according to which, it is composed of 



One atom of sulphur 16 



One atom of iron 28 



"44 

 Persulphuret consists of, according to 



Dr. Thomson. Mr. Hatchett. 



Two atoms of sulphur 32 32-16 



One atom of iron 28 27*84 



"eo" 60-00 



These statements are also very nearly similar. 



Putting the oxygen out of the question, it will be seen that 

 the specimen of copper ore from Hitterdahl is stated to consist 

 of 19 of sulphur, 7*5 of iron, and 69-5 of copper. Now in order 

 to take the simplest view of the subject, let us examine whether 

 these quantities are compatible with the supposition that this ore 

 may be a compound of an atom of sulphuret of copper with an 

 atom of sulphuret of iron. According to what has been already- 

 stated, 64 of copper combine with 16 of sulphur, or one-fourth 

 of its weight, then 69-5 would require nearly 17*4 of sulphur, 

 which being deducted from 19, the whole quantity, would leave 

 only 1*6 to combine with 7*5 of iron ; now the protosulphuret of 

 iron is composed of 16 sulphur and 28 iron ; consequently the 1*6 

 of sulphur would be sufficient for only 2*8 of the 7-5 of iron. It is 

 indeed true, that if we reckon 2*6 of the 4 as sulphur, which 



