10 I^R' HATCHETT ON MAGNETICAL PYRITES. 



alike to poflefs the property of enabling iron (o retain llie 

 power of magnctifni; but I fiiall conHder this more fully in 

 the following feflion. 



§ viir. 



From the whole which has been ftaled we find, 



General refults. i- That the fubflance called magnetical pyrites, which has 



Magnetic pyrites 111 tlierto been found only in Saxony and a few other places, is 

 is a Britilh .^ r, - n • i i i • ^ « • r- 



minera!, ^"^ ^ nrililh mineral, and that, in Caernarvonmire, it iorms a 



vein of confidcrable extent, breadth, and depth. 



—containing 2. That the component ingredients of it are fulphur and 



afcout 37 fulphur nietallic iron; the former being in the proportion of 36.50 or 

 and 6 1 iron. ^„ ■ ,, , , 



37, and the latter about 63.30 or 63. 



It differs in its ^' That the chemical and other properties of this fubftance 

 propeities from are very different from thofe of the common martial pyrites, 

 wTlchTomaVnr ^^^'^^^ however arealfocompofed of fulphur and iron, varying 

 jnarc fulphur. in proportion, from 52. 1 5 to 54.34 of fulphur, and from 47.85 

 to 45.66 of metallic iron ; the difference between the common 

 pyrites which were examined being therefore 2. 19, and the mean 

 proportions amounting to 53.24 of fulphur, and 46.75 of iron; 

 confequently,the difference between the relative proportions, in 

 the compofition of the magnetical pyrites and of the common 

 pyrites, is nearly 16.74, or 16.24. 

 It i» identically ^' That, as the magnetical pyrites agrees in analytical refults, 

 the fame as the as well as in all chemical and other properties, with that lul- 

 •iiurec. "' phuret of iron which hitherto has been only known as an 

 artificial product, there is no doubt but that it is identically the 

 fame; and we may conclude, that its proportions are moft pro- 

 bably fubje6led to a certain law, (as Mr. Proufl has obferve<l 

 in the cafe of the artificial fulphuret J which law, under certain 

 circumftances, and efpecially during the natural formation of 

 this fubflance in the humid way, may be fuppofed to a6l in an 

 almofl invariable manner, 

 Ib common py- ^' That, in the formation of common martial pyrites, there 

 nt(s the fulphur is a deviation from this law, and that fulphur becomes theprc- 

 prcdommates, dominant ingredient, which is variable in quantity, but which, by 

 the prefent experiments, has not been found to exceed 54 54-per 

 cent, a proportion, however, that poffibly may be furpalfed in 

 other pyiites, which have not as ^et been chemically ex- 

 amined, 



6. That 



