60 SMELTING 01? CUPREOUS PYRlTna. 



May be smdt- ]\f r. Gueniveau thinks therefore, that they mav he smelted 



like the boj^ iron ores with an ar£i::iUaceous carbonate or 



. . ' . '■• 



lime; and thon<:>h the iron produced might not be of prime 



quahty, it would answer for several purposes. This must 

 appear an object of considerable importance to those, who 

 have seen the vast quantities of scoriae near the works. The 

 only operations required are pounding and smelting ; and 

 the smelting would not be very expensive, if coke could be 

 employed, as is done at Clu ssy for the copper, where the 

 whole process is conducted in a very intelligent and econo-^ 

 niical manner. 

 Silex acts cher The observations nnd experiments here .given not only 

 inically m this j^^j ^^^ ^^ Consider silex, or quartz, as a metallurgic agent, 

 capable of separating iron in a state of combination from 

 copper, which it allows to melt alone or mixed with sulphur, 

 when assisted by the high temperature of the furnace ; but 

 "which eluci- serves to explain many passages in treatises on metallurgy. 

 ^hiTs^thaf oc- '^^^^s^ works offer nothing precise respecting tlie manner, in 

 cur in metal- which substances mixed or combined in ores act on one ano- 

 iurgic -works, ^j^^^,^ ^^^ allow the separation of the metal, which we seek 

 to obtain. The same facts teach us why various kinds of 

 scoriae are mixed with the ores or matts under different cir- 

 cumstances: some being employed as fluxes of thej gangues; 

 others only to give fluidity to the whole mass, and produce 

 a kind of solution, which facilitates tlieir reciprocal action ; 

 and others act as a medium to separate the iron, when they 

 are not already- saturated with it. At Chessy the scoria? of 

 the ore perform this office in the smelting of. the matts, as 

 has been said. The general opinion' of metallurgists there- 

 fore, who consider the addition of earthy substances to ores 

 as serving merely to form fusible compounds WitH their 

 gangues, without paying any attention to the action they 

 exert on metallic oxides, requires modification in many 

 cases. 



VIII. 



