14 ^*^' HATCHETT ON MAGNETICAL PYRITES, 



ofthe fulphur, at the time of the original formation of ihefe 

 fubftances, fo ihat the fiate of the fulphur is tending to that of 

 oxide, and thus the accctlion of a farther addition of oxygen 

 becomes facilitated. We have an example of fimilar eff'edls in 

 phofphorus, when (as is commonly faid) it is half burned, for 

 the purpofe of preparing the phofphorus bottles; and the pro- 

 peniily to vitriolization, obferved in many of the half-roafted 

 fulphureous ores, appears to me to arife from this caufe, rather 

 than from the mere diminution of the original proportion of 

 fulphur, or the actual immediate converfion of part of it into 

 fulphuric acid ; neverthelefs, I otfer this opinion, at prefent, 

 only as a probable conjecture, vvliich may be inveftigated by 

 future experiments and obfervations. 

 The magnetical Xhe magnetical properties of the fulphuret of iron which 

 fubhureTis a ^^^^ms the principal fubje6l of this Paper, muft be regarded as a 

 fcmarkable faft, remarkable fa6l ; for I have not found, in the various publica- 

 tions on magnetifm which I have had the means of confulting, 

 even the mofi: remote hint, that iron when combined with ful- 

 phur, is poirelTed of the power of receivmg and retaining the 

 magnetic fluid ; and, judging by the properties of common 

 pyrites, we might have fuppofed that fulphur annihilated this 

 power in iron, as indeed feems to have been the opinion of 

 mineralogifts, who have never enumerated magnetical attrac- 

 tion amongft the phyfical properties of thofe bodies; and, 

 although Werner, Widenmann, Emmerling, and Brochant,. 

 little or fcarcely have arranged the magnetical pyrites with the fulphurets of 

 noticed. jj-Qp^ yet the magnetical property could not with certainty be 



ftated as inherent in the fulphuret, for, at that time, this fub- 

 fiance had not been fubje6led to a regular chemical analylis, 

 and the magnetical property might therefore be fufpeded to 

 arife from interfperfed particles of the common magnetical iron 

 ore. This probably has been the opinion of the Abb^ Haiiy ; 

 for, in hisextenliveTreatife on Mineralogy lately publiflied, I 

 cannot find any mention made of the magnetical pyrites, either 

 amongft the fulphurets or amongft the other ores of iron. 

 The magnet faid In the mineral kingdom, a great variety of fubftances, and 

 to confift of iron ^^^^ f^^^ ^f jj^g gems, exert a feeble degree of attraction on 

 with lo to 20 , ,f ,r • ^r ■ n- , , 



oxigen. the magnetic needle, and lometimes alio acquire a ilight degree 



of polarity j * but, as this wonderful property has only been 



Cavallo on Magnetifm, page 73. 



obferved 



