\$ MR. HATCHETT ON MAGNETICAL PYRITES. 



lefs brittle, foluble in muriatic acid, and more or lefs fufceplible 

 of raagnetical impregnation ; fome of them form the mofl 

 powerful magnets hitherto difcovered. 

 Sulphur an^lroa ijulphur, in like manner, combines with iron in a large pro- 

 ha\^e fimilar ha- portion, forming the common pyrites, which are brittle, almofl 

 or quite infoluble in muriatic acid, and devoid of magnetical 

 properties. Sulphur in fmaller proportions, forms iulphurets 

 which are alio brittle, but are foluble in muriatic acid, anti 

 ftrougly fufceptible of magnetical impregnation. 

 So likewife Piiofphorus alfo, when combined with iron, makes it brittle, 



phofphorus and and enables it powerfully to receive and retain the magnetical 

 properties; fo that, confidering the great Similarity which pre- 

 vails in other refpeifls, it may not feem rafli to conclude, that 

 phofphorus (like carbon and fulphur,) when combined with 

 iron in a very large proportion, may form a fubftance incapable 

 of becoming magnetical, although, in fmaller proportion, (as 

 )ve have feen,) it conllitutes compounds which are not only 

 capable of receiving, but alfo of retaining, the magnetical pro- 

 perties, even fo far as, in fome cafes, to feem likely to form 

 magnets of great power ; and, fpeaking generally of the car- 

 burets, fulphurets, and pholphuretsof iron, I have no doubt but 

 that, by accurate experiments, we fhall find that a certain pro- 

 portion of the ingredients of each, conftitutes a maximum in the 

 magnetical power of thefe three bodies. When this maximum 

 has been afcertained, it would be proper to compare the relative 

 magnetical power of fleel (which hitherto has alone been em- 

 Mr. Mufhet, In the following Table, exhibits the proportion of 

 charcoal which difappeared, during the converfion of iron to the 

 different varieties of fubcarburet known in commerce. 



** When the carbon amounts to about ^-^ of tht >n^hole mafs, the 

 ^hafdhefs'Js at the maximum." Thomfon, Vol. I. p. 166 j and 

 Phil, Magazine, VOL XI-II. pp. 142 and 14-8. ^ 



ployed 



