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BOOK VII. 



can assay the ore at a very small expense, and smelt it only at a great 

 expense. Both processes, however, are carried out in the same way, for just 

 as we assay ore in a little furnace, so do we smelt it in the large furnace. Also 

 in both cases charcoal and not wood is burned. Moreover, in the crucible 

 when metals are tested, be they gold, silver, copper, or lead, they are mixed in 

 precisely the same way as they are mixed in the blast furnace when they 

 are smelted. Further, those who assay ores with fire, either pour out the 

 metal in a liquid state, or, when it has cooled, break the crucible and clean 



