BOOK XI. 
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 
