^ MR. HATCHETT ON MAGNETICAL PYRITES. 



ehemical as well as the magnetical properties; but, undoubted- 

 ly, by thefe procefTes, it is progredively converted, pert'eclly 

 or very nearly, into the metaUic Hate. 



Iron combined with a larger proportion of oxygen, fuch as 



the fine gray fpecular iron from Sweden, will not form a ful- 



phuret by the direct application of fulphur, in one operation; 



although it becomes of a dark brown colour, partly iridefcent, 



and is moderately attraded by a magnet. 



Magnetlcal Fifty grains of the magnetical pyrites, reduced to powder, 



pyrites combined ^^d mixed with three times the weight of fulphur, were diftilled 



morcof fulphur, i"^ retort, until the bulb became moderately red-hot. After 



the diftillation, the pyrites weighed 54. 50; confequenlly, the 



addition of fulphur was97;er cent, making the total = 45.50 or 



46 per cent. The powder was become greenifli-yellow, very 



like that of the common pyrites: it did not afford any fulplm- 



relted hydrogen, when digefled in muriatic acid ; but it never- 



theiefs was partially diflblved, and the folution, when examined 



by prufliate of potafli, and by ammonia, was notditlerent from 



that of the crude magnetical pyrites. 



•—was ftill at- The powder which had been diftilled with fulphur, and 



traced by the which had thus received an addition of 9 per cent, to its original 



magnet, quantity, xnas fiiil coj)able of bdn^ cornpleteJj/ taken vp by a . 



magnet, 

 » /• * I From the whole of the experiments which have been related. 



Iron cealcs to be r » 



a(fted on by the it is therefore evident, that iron, when combined with a confi- 

 jTiagnet when the ^^^.^j^jg proportion of fuIphur, is not only flill capable of receiv- 

 dofe of fulphur *^ . i • ir i t i i t 



Is at fome point , ing the magnetic property, but is alio thereby enabled to retam 



between 46 and j(^ ^rid thus (as I h^ve already remarked) becomes a complete 

 ^ "' magnet; and it is not a little curious, that iron combined (as 

 above ftated) with 45 or A^G per cent, of fulphur, is capable of 

 being taken up by a magnet, whilll iron combined with 52 per 

 cent, ormore, of fulphur, (although likewifein the metallic ftate,} 

 does not fenfibly affeci the magnetic needle; and hence, fmall 

 aii the difference may appear, there is reafon to conclude, that 

 the capacity of iron for magnetic action is deffroyed by a 

 certain proportion of fulphur, the efiedls of which, although little 

 if at all fenfible at 46 per cmt. are yet nearly or quite abfolule, 

 in this deflrudion of magnetic influence, before it amounts to 

 52. But, what the exatl intermediate proportion of fulphur 

 may be, which is adequate to produce this etfed, I have not as 

 yet determined by actual experiment, 



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