Analysis of the magnetlcal Pyrites, 21 9 



uhich are luore or less brittle, soluble in muriatic acid, and 

 jnore or less susceptible of magnetical impregnation, some 

 of them form the most powerful magnets hitherto discovered. 



Sulphur, in like manner, combines with iron in a large 

 proportion, forming the common pyrites, which arc brittle, 

 almost or quite insoluble in nuiriatic acid, and devoid of 

 magnetical properties. Sulphur, in smaller proportions, 

 forms sulphurets, which are also brittle, but are soluble 

 in muriatic acid, and strongly susceptible of magnetical 

 impregnation. 



Phosphorus also, when combined with iron, makes it • 

 brittle, and enables it powerfully to receive and retain the 

 nragnetical properties; so that, considering the great simi- 

 larity which prevails in other respects, it may not seem rash 

 to conclude, that phosphorus, (like carbon and sulphur,) 

 when combined with iron in a very large proportion, may 

 form a substance incapable of becoming magnetical, al- 

 though, in smaller proportions (as we have seen,) it con- 

 stitutes compounds which arc not only capable of receivlncr 

 but also of retaining the magnetical properties, even so far 

 as, in some cases, to seem likely to form magnets of great 

 power ; and, speaking generally of the carburets, sulphu- 

 rets, and phosphurets of iron, I have no doubt but that 

 by accurate experiments we shall find that a certain propor- 

 tion of the ingredients of each constitutes a maximiim in 

 the magnetical power of these three bodies. When this 

 maximum has been ascertained, jt would be proper to com- 

 pare the relative magnetical power of steel (which hitherto 

 has alone been employed to form artificial masnets) with 

 that of sulphuret and phosphuret of iron j each being first 

 examined in the form of a single mass or bar of equal 

 weight, and afterwards in the state of compound magnets, 

 formed, like the large horse-shoe magnets, by the separate 



coal which disappeared during the conversion of iron to the difflrent va- 

 rieties of subcarburct known in commerce, 

 •' Charcoal absorbed. Result. 



i-i2odth - - Soft cast steel. 



i-ioodth - - Common cast stcci, 



i-Qoth - - The same, but liHrdcr. 



i-5orh - - The same ; too haid for drawing. 



1-2 5th - - White cast iron. 



i-2cth - - Mottled ca.t iron. 



|-i:th - - Black cast iroti. 



" When the carbon amounts to about i-6oih of the whole ma.':, 'he VaH- 

 ness is at the maximum."— rThomson, vol. i. p. 166; and i'nil. M-^^- 

 vol. xiii. pp. 144 and I4.J(. 



arran'Tcnicut 



