BOOK XL 



497 



the second inclined side wall of the hood. Into the ends of the transverse 

 beams facing the third long wall, are mortised the ends of the same 

 number of rafters rising toward the rafters of the first inclined side of 

 the second hood, and in this manner is made the other inclined side of 

 the second hood. But to prevent this from falling in upon the opposite 

 inclined side of the hood, and that again upon the opposite vertical one, 

 there are many iron rods reaching from some of the rafters to those 

 opposite them ; and this is also prevented in part by means of a few tie-beams, 

 extending from the back of the rafters to the back of those which are behind 

 them. These tie-beams are two palms thick and wide, and have holes made 

 through them at each end ; each of the rafters is bound round with iron 

 bands three digits wide and half a digit thick, which hold together the ends 

 of the tie-beams of which I have spoken ; and so that the joints may be firm, 

 an iron nail, passing through the plate on both sides, is driven through the 

 holes in the ends of the beams. Since one weight counter-balances another, the 

 rafters on the opposite hoods cannot fall. The tie-beams and middle posts 

 which have to support the gutters and the roof, are made in every particular 

 as I stated above, except only that the second set of middle rafters are not 

 longer than the first set of middle rafters, and that the little beams which 

 reach from the back of each rafter of the second set of middle rafters nearly 

 to the gutter are not longer than the little beams which reach from the back 

 of each rafter of the first set of middle rafters almost to the gutter. In this 

 part of the building, against the second long wall, are the furnaces in which 

 copper is alloyed with lead, and in which " slags " are re-smelted. Against 

 the third long wall are the furnaces in which silver and lead are liquated from 

 copper. The interior is also occupied by two cranes, of which one deposits 

 on the ground the cakes of copper lifted out of the moulding pans ; the other 

 lifts them from the ground into the second furnace. 



On the third and the fourth long walls are set twenty-one beams eighteen 

 feet and three palms long. In mortises in them, two feet behind the third long 

 wall, are set the ends of the same number of rafters erected opposite to the 

 rafters of the other inclined wall of the second furnace hood, and in this 

 manner is made the third inclined wall, exactly similar to the others. The 

 ends of as many rafters are mortised into these beams where they are fixed in 

 the fourth long wall ; these rafters are erected obliquely, and rest against the 

 backs of the preceding ones and support the roof, which consists entirely of 

 burnt tiles and has the usual substructures. In this part of the building 

 there are two rooms, in the first of which the cakes of copper, and in the other 

 the cakes of lead, are stored. 



In the space enclosed between the ninth and tenth transverse walls and 

 the second and fifth long walls, a post twelve feet high and two feet wide and 

 thick is erected on a rock foundation ; it is distant thirteen feet from the 

 second long wall, and six from the fifth long wall. Upon this post and upon 

 the ninth transverse wall is laid a beam thirty-three feet and three palms 

 long, and two palms wide and thick. Another beam, also of the same length, 

 width and thickness, is laid upon the same post and upon the tenth transverse 



