498 BOOK XI. 



wall, and the ends of these two beams where they meet are joined by means 

 of iron staples. On these beams and on the fifth long wall are placed ten 

 cross-beams, eight feet and three palms long, the first of which is placed on 

 the ninth transverse wall, the last on the tenth, the remainder in the space 

 between them ; they are distant from one another three feet. Into the 

 ends of the cross-beams facing the second long wall, are mortised the ends of 

 the same nvmiber of rafters inclined toward the posts which stand vertically 

 upon the second long waU. This, again, is the manner in which the inchned 

 side of the furnace hood is made, just as with the others ; at the top 

 where the fumes are emitted it is two feet distant from the vertical side. 

 The ends of the same number of rafters are mortised into the cross-beams, 

 where they are set in the fifth long wall ; each of them is set up obhquely and 

 rests against the back of one of the preceding set ; they support the roof, 

 made of burnt tiles. In this part of the building, against the second long 

 wall, are four furnaces in which lead is separated from silver, together with 

 the cranes by means of which the domes are hfted from the crucibles. 



In that part of the building which Ues between the first long wall and 

 the break in the second long wall, is the stamp with which the copper cakes 

 are crushed, and the four stamps with which the accretions that are chipped 

 off the waUs of the furnace are broken up and crushed to powder, and likewise 

 the bricks on which the exhausted Uquation cakes of copper are stood to 

 be " dried." This room has the usual roof, as also has the space between 

 the seventh transverse wall and the twelfth and thirteenth transverse walls. 



At the sides of these rooms are the fifth, the sixth, and the third long 

 walls. This part of the building is divided into two parts, in the first of 

 which stand the httle furnaces in which the artificer assays metals ; and the 

 bone ash, together with the other powders, are kept here. In the other room 

 is prepared the powder from which the hearths and the crucibles of the fur- 

 naces are made. Outside the building, at the back of the fourth long wall, 

 near the door to the left as you enter, is a hearth in which smaller 

 masses of lead are melted from large ones, that they may be the more easily 

 weighed ; because the masses of lead, just as much as the cakes of copper, 

 ought to be first prepared so that they can be weighed, and a definite weight 

 can be melted and alloyed in the furnaces. To begin with, the hearth in 

 which the masses of lead are hquefied is six feet long and five wide ; it is 

 protected on both sides by rocks partly sunk into the earth, but a palm higher 

 than the hearth, and it is lined in the inside with lute. It slopes toward the 

 middle and toward the front, in order that the molten lead may run down 

 and flow out into the dipping-pot. There is a wall at the back of the hearth 

 which protects the fourth long wall from damage by the heat ; this wall, 

 which is made of bricks and lute, is four feet high, three palms thick, and five 

 feet long at the bottom, and at the top three feet and two palms long ; there- 

 fore it narrows gradually, and in the upper part are laid seven bricks, the 

 middle ones of which are set upright, and the end ones inclined ; they are all 

 thickly coated with lute. In front of the hearth is a dipping-pot, whose pit is 

 a foot deep, and a foot and three palms wide at the top, and gradually narrows. 



