The upper bellows-board is joined to the head of the bellows in the
following way. An iron plate7, a palm wide and one and a half palms long,
is first fastened to the head at a distance of three digits from the end ; from
this plate there projects a piece three digits long and two wide, curved
in a small circle. The other side has a similar plate. Then in the same
part of the upper board are fixed two other iron plates, distant two digits
from the edge, each of which are six digits wide and seven long ; in each
of these plates the middle part is cut away for a little more than three
digits in length and for two in depth, so that the curved part of the plates
on the head corresponding to them may fit into this cut out part. From
both sides of each plate there project pieces, three digits long and two
digits wide, similarly curved into small circles. A little iron pin is passed
through these curved pieces of the plates, like a Uttle axle, so that the upper
board of the bellows may turn upon it. The little axle is six digits long and a
Uttle more than a digit thick, and a small groove is cut out of the upper
board, where the plates are fastened to it, in such a manner that the Uttle axle
when fixed to the plates may not fall out. Both plates fastened to the
beUows-board are affixed by four iron nails, of which the heads are on the
inner part of the board, whereas the points, clinched at the top, are
transformed into heads, so to speak. Each of the other plates is fastened
to the head of the beUows by means of a nail with a wide head, and by two
other nails of which the heads are on the edge of the bellows-head. Midway
between the two plates on the bellows-board there remains a space two
palms wide, which is covered by an iron plate fastened to the board by
Uttle nails ; and another plate corresponding to this is fastened to the head
between the other two plates ; they are two palms and the same number
of digits wide.
The hide is common to the head as to aU the other parts of the body ;
the plates are covered with it, as weU as the front part of the upper bellowsboard, and both the bows and the back of the head of the bellows, so that the
wind may not escape from that part of the bellows. It is three palms and as
many digits wide, and long enough to extend from one of the sides of the
lower board over the back of the upper ; it is fastened by many T-headed
nails on one side to the upper board, and on the other side to the head of
the bellows, and both ends are fastened to the lower bellows-board.
In the above manner the beUows is made. As two are required for each
furnace, it is necessary to have twelve bellows, if there are to be six furnaces
in one works.
Now it is time to describe their framework. First, two siUs a Uttle
shorter than the furnace wall are placed on the ground. The front one of
these is three palms wide and thick, and the back one three palms and two
digits. The front one is two feet distant from the back wall of the furnace, and
the back one is six feet three palms distant from the front one. They are set into
the earth, that they may remain firm ; there are some who accompUsh this by
means of pegs which, through several holes, penetrate deeply into the ground.
