1thick, and nineteen feet and a palm long; these are
placed three feet distant
from one another. As the second wall is two feet higher than the first wall,
recesses are cut in the back of it two feet high, one foot wide, and a palm deep,
and in these recesses, as it were in mortises, are placed one end of each of
the beams. Into these ends are mortised the bottoms of just as many posts;
these posts are twenty-four feet high, three palms wide and thick, and from
the tops of the posts the same number of rafters stretch downward to the
ends of the beams superimposed on the first wall; the upper ends of the
rafters are mortised into the posts and the lower ends are mortised into the
ends of the beams laid on the first wall; the rafters support the roof,
which consists of burnt tiles. Each separate rafter is propped up by a
separate timber, which is a cross-beam, and is joined to its post. Planks
close together are affixed to the posts above the furnaces; these planks are
about two digits thick and a palm wide, and they, together with the wicker
work interposed between the timbers, are covered with lute so that there may
be no risk of fire to the timbers and wicker-work. In this practical manner
is constructed the back part of the works, which contains the bellows, their
frames, the mechanism for compressing the bellows, and the instrument for
distending them, of all of which I will speak hereafter.
from one another. As the second wall is two feet higher than the first wall,
recesses are cut in the back of it two feet high, one foot wide, and a palm deep,
and in these recesses, as it were in mortises, are placed one end of each of
the beams. Into these ends are mortised the bottoms of just as many posts;
these posts are twenty-four feet high, three palms wide and thick, and from
the tops of the posts the same number of rafters stretch downward to the
ends of the beams superimposed on the first wall; the upper ends of the
rafters are mortised into the posts and the lower ends are mortised into the
ends of the beams laid on the first wall; the rafters support the roof,
which consists of burnt tiles. Each separate rafter is propped up by a
separate timber, which is a cross-beam, and is joined to its post. Planks
close together are affixed to the posts above the furnaces; these planks are
about two digits thick and a palm wide, and they, together with the wicker
work interposed between the timbers, are covered with lute so that there may
be no risk of fire to the timbers and wicker-work. In this practical manner
is constructed the back part of the works, which contains the bellows, their
frames, the mechanism for compressing the bellows, and the instrument for
distending them, of all of which I will speak hereafter.
In front of the furnaces is constructed the third long wall and likewise
the fourth. Both are nine feet high, but of the same length and thickness as
the other two, the fourth being nine feet distant from the third; the
third is twenty-one and a half feet from the second. At a distance of
twelve feet from the second wall, four posts seven and a half feet high, a cubit
wide and thick, are set upon rock laid underneath. Into the tops of the
posts the roof beam is mortised; this roof beam is two feet and as many
palms longer than the distance between the second and the fifth transverse
walls, in order that its ends may rest on the transverse walls. If there should
not be so long a beam at hand, two are substituted for it. As the length of
the long beam is as above, and as the posts are equidistant, it is necessary
that the posts should be a distance of nine feet, one palm, two and two-fifths
digits from each other, and the end ones this distance from the transverse
walls. On this longitudinal beam and to the third and fourth walls are fixed
twelve secondary beams twenty-four feet long, one foot wide, three palms
thick, and distant from each other three feet, one palm, and two digits. In
these secondary beams, where they rest on the longitudinal beams, are mortised
the ends of the same number of rafters as there are posts which stand on the
second wall. The ends of the rafters do not reach to the tops of the posts,
but are two feet away from them, that through this opening, which is like
the open part of a forge, the furnaces can emit their fumes. In order that
the rafters should not fall down, they are supported partly by iron rods,
which extend from each rafter to the opposite post, and partly supported
by a few tie-beams, which in the same manner extend from some rafters to
the posts opposite, and give them stability. To these tie-beams, as well as
to the rafters which face the posts, a number of boards, about two digits thick
and a palm wide, are fixed at a distance of a palm from each other, and are
the fourth. Both are nine feet high, but of the same length and thickness as
the other two, the fourth being nine feet distant from the third; the
third is twenty-one and a half feet from the second. At a distance of
twelve feet from the second wall, four posts seven and a half feet high, a cubit
wide and thick, are set upon rock laid underneath. Into the tops of the
posts the roof beam is mortised; this roof beam is two feet and as many
palms longer than the distance between the second and the fifth transverse
walls, in order that its ends may rest on the transverse walls. If there should
not be so long a beam at hand, two are substituted for it. As the length of
the long beam is as above, and as the posts are equidistant, it is necessary
that the posts should be a distance of nine feet, one palm, two and two-fifths
digits from each other, and the end ones this distance from the transverse
walls. On this longitudinal beam and to the third and fourth walls are fixed
twelve secondary beams twenty-four feet long, one foot wide, three palms
thick, and distant from each other three feet, one palm, and two digits. In
these secondary beams, where they rest on the longitudinal beams, are mortised
the ends of the same number of rafters as there are posts which stand on the
second wall. The ends of the rafters do not reach to the tops of the posts,
but are two feet away from them, that through this opening, which is like
the open part of a forge, the furnaces can emit their fumes. In order that
the rafters should not fall down, they are supported partly by iron rods,
which extend from each rafter to the opposite post, and partly supported
by a few tie-beams, which in the same manner extend from some rafters to
the posts opposite, and give them stability. To these tie-beams, as well as
to the rafters which face the posts, a number of boards, about two digits thick
and a palm wide, are fixed at a distance of a palm from each other, and are