BOOK X. 467 



of the works in which ore is smelted. In the space between the middle and 

 the front long walls and between the second^' and the third transverse walls are 

 the bellows, the machinery for depressing and the instrument for raising them. 

 A drum on the axle of a water-wheel has rundles which turn the toothed 

 drum of an axle, whose long cams depress the levers of the bellows, and also 

 another toothed drum on an axle, whose cams raise the tappets of the stamps, 

 but in the opposite direction. So that if the cams which depress the levers 

 of the bellows turn from north to south, the cams of the stamps turn from 

 south to north. 



Lead is separated from gold or silver in a cupellation furnace, of 

 which the structure consists of rectangular stones, of two interior walls of which 

 the one intersects the other transversely, of a round sole, and of a dome. Its 

 crucible is made from powder of earth and ash ; but I will first speak of the 

 structure and also of the rectangular stones. A circular wall is built four 

 feet and three palms high, and one foot thick ; from the height of two feet 

 and three palms from the bottom, the upper part of the interior is cut away 

 to the width of one palm, so that the stone sole may rest upon it. There are 

 usually as many as fourteen stones ; on the outside they are a foot and a 

 palm wide, and on the inside narrower, because the inner circle is much 

 smaller than the outer ; if the stones are wider, fewer are required, if 

 narrower more ; they are sunk into the earth to a depth of a foot and a palm. 

 At the top each one is joined to the next by an iron staple, the points of 

 which are embedded in holes, and into each hole is poured molten lead. This 

 stone structure has six air-holes near the ground, at a height of a foot above 

 the ground ; they are two feet and a palm from the bottom of the stones ; 

 each of these air-holes is in two stones, and is two palms high, and a palm and 

 three digits wide. One of them is on the right side, between the wall which 

 protects the main wall from the fire, and the channel through which the 

 litharge flows out of the furnace crucible ; the other five air-holes are 

 distributed all round at equal distances apart ; through these escapes the 

 moisture which the earth exhales when heated, and if it were not for these 

 openings the crucible would absorb the moisture and be damaged. In such a 

 case a lump would be raised, like that which a mole throws up from the earth, 

 and the ash would float on the top, and the crucible would absorb the silver-lead 

 aUoy ; there are some who, because of this, make the rear part of the structure 

 entirely open. The two inner walls, of which one intersects the other, are 

 built of bricks, and are a brick in thickness. There are four air-holes in 

 these, one in each part, which are about one digit's breadth higher and wider 

 than the others. Into the four compartments is thrown a wheelbarrowful 

 of slag, and over this is placed a large wicker basket full of charcoal dust. 

 These walls extend a cubit above the ground, and on these, and on the ledge 

 cut in the rectangular stones, is placed the stone sole ; this sole is a palm and 

 three digits thick, and on all sides touches the rectangular stones ; if there 

 are any cracks in it they are filled up with fragments of stone or brick. The 

 front part of the sole is sloped so that a channel can be made, through which 



^'In Agricolas' text this is " first," — obviously an error. 



