144 Commentaries on the 



some of clay. In some the smelting is performed with wood, in 

 others with charcoal ; in some the mouths or apertures are stopped 

 up, and in others left open. In some, the ore and wood are mingled 

 together ; in others, the wood or charcoal is not in contact with the 

 ore, but the flame only, whence they are called reverberatory 

 furnaces/ 



* Of the smelting of Ores. Having made the proper mixture, 

 and prepared the furnaces and the machines for supplying them 

 with wind, the smelter must heat or anneal the furnace, if, from 

 being new or newly repaired, it requires it ; for, if the ore be thrown 

 in whilst the furnace is cold, it is apt, upon getting warm, to fly or 

 crack, with danger to the bystanders: and if it be moist, in the 

 summer, the same thing will happen, and it will explode with very 

 great force. During the first few hours, charcoal is first thrown in, 

 then a basket of slags, then one of charcoal, and so on, until it be 

 time to add the mixed ore. Haifa basketful of this is then thrown 

 in, and upon that a basket of charcoal, and so on, until the furnace 

 begins to work, after which, alternate basketsful of mixed ore and 

 charcoal are thrown in. One or two cargas of charcoal are con- 

 sumed for each charge, according to the nature of the ore ; some 

 ores requiring the furnace to be moderately filled ; others, that it 

 should be filled to the top. If the ore be not earthy, but clean, the 

 furnace may be charged freely. 



' The furnace being thus arranged and brought into play, smelts 

 four charges in twenty-four hours, the ingots being tapped off from 

 time to time ; for which purpose, an aperture is made below the 

 bridge of the breast-pan, and the melted portion runs off into the 

 float. The first ingot let off, after repairing the furnace, is called 

 calentadura, and is smaller than the others, because the furnace 

 becomes coated with vitrified ore adhering to it, and care is there- 

 fore taken not to throw in rich ores for the calentadura. The fused 

 metal being let off, the bridge is stopped up, the breast-pan is 

 cleared out, charcoal dust is thrown into and around it, and the 

 furnace is again set to work. The portions which may have adhered 

 to it are taken off last of all, and are mixed with the ores in future 

 smeltings. 



* After the smelting is performed, the furnace is uncharged, 

 which is done in the following manner. The charges of ore being 

 all finished, slags and charcoal alone are thrown in, until all the 

 smelted ore has flowed into the breast-pan, when the furnace 

 throws oft' a very beautiful flame. The wall of mud bricks and 

 everything which may have adhered to it, are then broken down 

 with a crow or iron bar of about twenty-five pounds weight. And 

 here the unfortunate smelters suffer much, during an hour of great 

 labour ; for the furnace is hot in the extreme, the crow is heavy, 

 and the incrusted matter adheres very closely. The smoke and 

 vapour from the slag, which are quenched by pouring water upon 

 them, and which are consequently carried down to the feet of the 



