$^. Mj»^J^» 'Napier o?i Ci/pper Sinelti)tg. 



which produces the purest metal the ordinary process of smelting 

 can give ; it is termed best select. 



The bottoms are collected, and if not very impure, are roasted 

 to oxidate the foreign metals, and an inferior quality of copper 

 made from it termed tile. The composition of copper bottoms 

 Vdsies exceedingly. The following analysis is of a fair sample »rm 



Td Copper 74*0 ' 8f"W 



Tin 13-8 >.iM 



Antimony .... 4*5 fxi^) 



-iioa bti^a rt Lead -8 % 



^ ^ ?§^' Iron 2-5 ^ 



noitouhsx ^ii ^«'Sulphur .... 39 



-TBo "io BtB t)di tiiovj , i .« 



lb til by^&it M Ud'H f- ^^'^ maod 



|, ,3Ihe following is from Le Play, but we have seldom met with 



any so impure ; and with such bottoms, the regulus above would 



l^tjj^ pjiffe. jenough to make select : — 



Qdlfd {ij^B n Copper 66*2 , u 



<fl99g 37«d aV/ .dQKar^Oij 

 isqoiq ban ^soQcrfstbn'i^ 

 baiavo!) ^snmiiio Arsenic 

 y[hs9a 81 Sulphur 



28-4 uft 9dl jto cTifiib 

 8^7. //Ino on aiadw 



tra^^ ^<> sbixodifa dliw 



-moo 1(1'* qq[U fnfiw ;_b97B8 IIb 



9/1^ u '< '^- . 1 , (Itiv/ bonid 



Copper bottoms are occasionally found at the bottQ^jpC^ 

 first pig in roasting blue metal; these are more impure than 

 when selected ore is used, and is no doubt the sort given by 

 Le Play. They are also found in fusing calcined coarse metal 

 with Australian ores, and in fusing calcined fine metal. When 

 best select is to be made from Cornish ores, the last process is 

 considered best. The method of selecting is sometimes practised 

 with inferior ores to obtain touffh cake copper. 



The next operation the copper is subjected to depends in a 

 great measure upon the quality of the copper obtained from the 

 roasting operation. If it be blistered, nothing further is required 

 but refining ; but if coarse copper, it must have another roasting. 

 In some smelting-works it is put into the refining-furnace and 

 there roasted before refining ; in other works a separate furnace 

 is used for this operation, in which it is brought to the quality 

 of blister. The separate furnace is preferable, as it preserves 

 the refining-fumace from being contaminated with impure metal, 

 a prevalent source of annoyance. This roasting is done in the 

 same manner as described for the regulus. About four tons of 

 coarse copper form a charge. The high heat required to fuse 

 the copper facihtates the scorifying of the alloy. The action may 

 be defined thus :-r-the copper is oxidized by the aii*, which oxide 



