!21-i Analysis of the via^nctical Pyrites, 



results, as well as in all chemical and other properties, with 

 that sulphuret of iron which hitherto has been only known 

 as an artificial product, there is no doubt but that it is iden- 

 tically the same ; and we may conclude that its proportions 

 are most probably subjected to a certain law, (as Mr. Proust 

 has observed in the case of the artificial sulphuret,) which 

 law, under certain circumstances, and especially during the 

 natural formation of this .--ubstance in the humid way, may 

 be supposed to act in an almost invariable manner. 



5. That in the formation of common martial pyrites 

 there is a deviation from this law, and that sulphur becomes 

 the predominant ingredient, which is variable in quantity, 

 but which, hy the present experiments, has not been found 

 to exceed o4'34 per cent. ; a proportion, however, that pos- 

 sibly may be surpassed in other pyrites which have not as 

 yet been chemically examined, 



G. That iron, when combined naturally or artificially 

 with 36-30 or 37 of sulphur, is iiot only still capable of 

 receiving the magnetic fluid, but is also rendered capable 

 of retaining it, so as to become in every respect a perma- 

 nent magnet ; and the- same may, in a great measure, be 

 inferred respecting iron which has been artificially com- 

 bined with 45-50 per cent, of sulphur. 



7. That, beyond this proportion of 45-50 or 46 per cent, 

 of sulphur, (in the natural common pyrites,) all suscepti- 

 bility of the magnetic influence appears to be destroyed j 

 and, although the precise proportion which is capable of 

 producing this effect, has not as yet been determined by 

 actual experiment, it is certain that the limits are between 

 45-50and 52-15; unless some unknown alteration has taken 

 place in the state of the sulphur, or of the iron, in the com- 

 mon martial pyrites. 



8. That, as carbon, when combined in a certain propor- 

 tion with iron, (forming steel,) enables it to become a per- 

 manent magnet, and as a certain proportion of sulphur 

 communicates ihe same quality to iron, so also were found 

 to be the efiects of phosphorus ; for the phosphuret of iron, 

 in this respect, was by much the most powerful, at least 

 when considered comparatively with sulphuret of iron. 



9. and lastly. That as carbon, sulphur, and phosphorus, 

 produce, by their union with iron, many chemical effects of 

 much similarity, so do each of them, when combined with 

 that metal in certain proportions, not only permit it to re- 

 ceive, but also give it the peculiar power of retaining, the mag- 

 netical properties; and thus henceforth, in addition to that 

 carburet of iron called steel, certain sulphurets and phos- 



1 phureta 



