in the Pyrites. 139 



to the matters under treatment, that they may not 

 go oil too foon in the fire, but have time either td 

 work or to be worked upon; as we fee from the 

 procucTtion of fulphur, where the alkali is only given 

 as a body to the vitriolic acid -, fometimes on inti- 

 mately mixing different things together, though 

 in themfelves improper for the intended process i 

 when new combination':, qualifies, and effects, 

 muft needs be produced. 



Now, to apply all this to the volatilifation of the 

 iron-earth of the pyrites ; it is ceitain, that this 1:5 

 not fo eafily effected with iron itfelf, as with the 

 iron-partic.es, ftilJ exifttng in the ore or pyrites: 

 and what is decifive, take a crude fulphur made in 

 clay veiTels, d.ftil or burn it off, and examining 

 the earth remaining behind, with the magnet, this 

 latter will be femd to attract the for mer. 



Whether, and how far, the coppery earth goes 

 in part over, in the diftillation, or difulfburation 

 of the pyrites, along witn the fulphur, as 1 have 

 not been able to make John Agric old's experiment, 

 mult be left to be considered, and reft upon the 

 truth of his relation, which is as follows : 



c Having once made an oleum fulphuris, or oil 



1 of Julphur, the faces, or remainder, I revet be 



* ra&cMer fourteen days in a moderate fire ; after - 

 4 wards committed them well luted down to a 



* wind- furnace, giving tor fix hours a ftrong fire ; 

 i then I wanted to calcine the faces quite white, as 



* my intention v/as to make fomething elfe of 

 4 I em. Now, upon breaking up the crucible, [ 



* found on the upper part, a few faces, not white 



* but grey, and beneath, a beautiful regulus, of a 

 1 blood-red colour, and very fparkling. I won- 



' dered 



