of the Pvrites; 343 



IV. To the operation of Crude-smelting. 



The operation of fmeking ores is the reparation 

 of the metals, fir ft, from the parts, reducing me- 

 tals to ores, namely, the fulphur, arfenic, and the 

 un metallic earth, intimately lodged in the ore- mix- 

 tion ; and befides, from unmetallic, ftoney, earthy 

 matters, externally adhering thereto, and incapa- 

 ble of being warned therefrom. With us at -Fri- 

 berg, this operation is principally two- fold, name- 

 ly, (i.) the crude-working \ (2.) the lead-work- 

 ing, from which afterwards flows the copper- work- 

 ing. The crude-working is that wherein the ores in 

 their crude (late, that is, not only with the adher- 

 ing unfeparatcd mineral matters, but alfo in their 

 unrGafted ftate, are lodged in the furnace, and 

 ("melted with ferviceable, rluxile flags, and the bell 

 or pured part of them brought to fome degree of 

 concentration, or to a regulus, called crude-fione. 

 The lead-working, to which the above crude-done 

 is taken, after a previous roafting for three or four 

 times, and the ore, employed therein, and which 

 is moftly glitter or lead-ore, and rich filver-ore, is 

 not only well cleaned, by picking, (lamping, and 

 warning, but has alio undergone a number of road- 

 fires, and is well feparatcd from the fulphur and 

 arfenic. My only reafon for comparing both thefe 

 operations together i>, that in the firft, the ores are 

 undamped, unwarned, and unroafted, but in the 

 fecond, well parted and roafted, without making 

 any di(tinc"b head of our copper- working^ as it co- 

 incides with, and alfo flows from the lead-working \ 

 where, namely, the lead-ftone^ that is, the crude 

 copper cake, or regulus, fettling down from the 

 former, alfo afcer repeated burnings or roaftings, 

 when it comes to be denominated copper -ftone, is 



Z 4 firft: 



