Analysis of the magnet icqI Pyrites. 217 



Ivses show that the crystallized pyrites contain loss sulphur 

 than the radiated pyrites, I might be induced to adopt the 

 contrary opinion. But I am inclined to attribute the effect 

 of vitriolization observed in -some of the pyrites, not so 

 much to the proportion, as to the state of the sulphur in 

 the compound; for I much suspect that a predisposition to. 

 vitriolization in these pyrites is produced by a small portioq 

 of oxygen being previously combined with a part, or with 

 the general mass of the sulphur, at the time of the original 

 formation'of these substances, so that the state of the sul- 

 phur is tending to that of oxide, and thus the accession of 

 ii further addition of oxygen becomes facilitated. We have 

 an example of similar etlects in phosphorus, when (as is. 

 commonly said) it is half burned, for the purpose of pre- 

 paring the phosphorus bottles ; and the propensity to vitriol- 

 ization, observed in many of the half roasted sulphureous 

 ores, appears to me to arise from this cause, rather than 

 Irom the mere diminution of the original proportion of 

 sulphur, or the actual immediate conversion of part of it 

 into sulphuric acid ; nevertheless, I offer this opinion, at 

 present, only as a probable conjectuix', which may be in- 

 vestigated by future experiments and observations. 



The magnetical properties of the sulphuret of iron, which 

 forms the principal subject of this paper, must be regarded 

 as a remarkable fact ; for I have not found, in the various 

 publications on magnetism which I have had the means of 

 consulting, even the most remote hint, that iron, when 

 combined with sulphur, is possessed of the power of recettf- 

 ing and retaining the magnetic fluid ; and, judging by the 

 properties of common pyrites, we might have supposed that 

 sulphur annihilated this power in iron, as indeed seems to 

 have been the opinion of mineralogists, who have never 

 enumerated magnetical attraction amongst the physical 

 properties of those bodies ; and, although Werner, Widen - 

 niann, Enimerling, and Brochant, have arranged the ma"- 

 nctical pyrites with the sulphurets of iron, yet the mag- 

 netical property could not with certainty be stated as inhe- 

 rent in the suiphuret ; for, at that tinie, this substano* had 

 not been subjected to a regular chemical analysis, and the 

 magnetical property might therefore be suspected to arise 

 from interspersed particles of the comnjon magnetical iron 

 ore. This probably has been the opinion of the abbe Haiiv; 

 for, in his extonsiv'c Treatise on JNIineralogy, lately pub- 

 lished, I cannot lind any mention made of the magnetical 

 pyrites, either amongst the sulphurets or anioncst the other 

 ores of iron. 



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