BOOK VII. 



223 



the metal from slag ; and in the same way the smelter, as soon as the metal 

 flows from the furnace into the forehearth, pours in cold water and takes the 

 slag from the metal with a hooked bar. Finally, in the same way that gold 

 and silver are separated from lead in a cupel, so also are they separated in 

 the cupellation furnace. 



It is necessary that the assayer who is testing ore or metals should be 

 prepared and instructed in all things necessary in assaying, and that he 

 should close the doors of the room in which the assay furnace stands, lest 



Round assay furnace. 



Rectangular assay furnace. 



