114 Anatii ?/? of the if> agnetical Pyrites. 



iiiilar. The speciiic g.avity was 43f)n, whilst (as I have 

 ah'cady remarked) that of the in; gaelicul pyrites is 43 IS. 



§vir. 



So far, therefore, as can bi proved by similarity In che- 

 mical properties a.nd aualysi:^, the maguetical pyrites is in- 

 disputabh' a natural suipharet, completely the same with 

 that which till now has been onlv known as an artificial 

 product; hut, that the mind may he perfectly satisfied, an- 

 other question must be solved, namely, flow far do thcv 

 accord in receiving and relaiuing the property of mag- 

 netism ? Common pyrites do not appear to affect the mag- 

 netic needle; or, if some of them slightly act by attraction, 

 (which, however, I never could percenc, nor recollect to 

 have read in works expressly relating to magnetism,) yet 

 thev do not possess, nor appear capable of acquiriug, any 

 mao-netic polarity. As, therefore, the iron of pyrites is un- 

 doubtedlv in the metallic state, and in a considerable pro- 

 portion, the destruction of this characteristic property of 

 metallic iron must be ascribed to the other ingredient — • 

 sulphur. 



But we have lately seen, that a natural combination of 

 iron with 36*30 or 37 per cent, of sulphur, is in possession 

 of all the properties supposed hitherto to appertain (in any 

 marked degree) almost exclusively to chc well known mag- 

 netic iron ore ; and that the combination alluded to is strictly 

 chemical, and not (as at first might have been imagined) 

 a mixture of particles of magnetic iron ore with common 

 pvrites*. 



' This is certainly very remarkable ; and it induced me to 

 examine the effects produced by sulphur on the capacity of 

 metallic iron for receiving and retaining the magnetic pro- 

 perties. I therefore prepared some sulphuret of iron by 

 addin"' a large quantily of sulphur to fine iron wire in a 

 moderate red heat. 



The internal colour and lustre of the product were not 

 very unlike those of the magnetical pyrites; and, after the 

 mass had been placed during a few hours between mag- 

 nelical bars, I found that it possessed so strong a degree 

 of polarity as to attract or repel the needle completely round 

 upon its pivot;, and, although several weeks have elapsed 



* This has b-en sufficiently proved by the facts which have been 

 stated ; I shall however add, that upon digesting ii mixture of the powder 

 of common pvritei and iron tilings in muriatic acid, I only obtained hy- 

 drogen gas, exactly as it i had cniploved tlic iron tilings without the 



pyriri., . 



since 



