The body of the trolley is made of wood from the Ostrya or any other
hard tree, and is a cubit long, a foot wide, and three palms thick; on both
edges of it the lower side is cut out to a height and width of a palm, so that
the remainder may move backward and forward between the two beams of
the crane-arm; at the front, in the middle part, it is cut out to a width of
two palms and as many digits, that a bronze pulley, around a small iron
axle, may turn in it. Near the corners of the trolley are four holes, in which
as many small wheels travel on the beams of the crane-arm. Since this
trolley, when it travels backward and forward, gives out a sound somewhat
similar to the barking of a dog, we have given it this name38. It is propelled
forward by means of a crank, and is drawn back by means of a chain. There
is an iron hook whose ring turns round an iron pin fastened to the right side
of the trolley, which hook is held by a sort of clavis, which is fixed in the
right beam of the crane-arm.
hard tree, and is a cubit long, a foot wide, and three palms thick; on both
edges of it the lower side is cut out to a height and width of a palm, so that
the remainder may move backward and forward between the two beams of
the crane-arm; at the front, in the middle part, it is cut out to a width of
two palms and as many digits, that a bronze pulley, around a small iron
axle, may turn in it. Near the corners of the trolley are four holes, in which
as many small wheels travel on the beams of the crane-arm. Since this
trolley, when it travels backward and forward, gives out a sound somewhat
similar to the barking of a dog, we have given it this name38. It is propelled
forward by means of a crank, and is drawn back by means of a chain. There
is an iron hook whose ring turns round an iron pin fastened to the right side
of the trolley, which hook is held by a sort of clavis, which is fixed in the
right beam of the crane-arm.
At the end of the crane-post is a bronze pulley, the iron axle of which is
fastened in the beams of the crane-arm, and over which the chain passes
as it comes from the frame, and then, penetrating through the hollow in the
top of the trolley, it reaches to the little bronze pulley of the trolley, and passing
over this it hangs down. A hook on its end engages a ring, in which are
fixed the top links of three chains, each six feet long, which pass through
the three iron rings fastened in the holes of the claves which are fixed into
the middle iron band of the dome, of which I have spoken.
fastened in the beams of the crane-arm, and over which the chain passes
as it comes from the frame, and then, penetrating through the hollow in the
top of the trolley, it reaches to the little bronze pulley of the trolley, and passing
over this it hangs down. A hook on its end engages a ring, in which are
fixed the top links of three chains, each six feet long, which pass through
the three iron rings fastened in the holes of the claves which are fixed into
the middle iron band of the dome, of which I have spoken.
Therefore when the master wishes to lift the dome by means of the
crane, the assistant fits over the lower small iron axle an iron crank, which
projects from the upright beam a palm and two digits; the end of the little
axle is rectangular, and one and a half digits wide and one digit thick; it is
set into a similar rectangular hole in the crank, which is two digits long and a
little more than a digit wide. The crank is semi-circular, and one foot three
palms and two digits long, as many digits wide, and one digit thick. Its
handle is straight and round, and three palms long, and one and a half digits
thick. There is a hole in the end of the little axle, through which an iron
pin is driven so that the crank may not come off. The crane having four
drums, two of which are rundle-drums and two toothed-wheels, is more easily
moved than another having two drums, one of which has rundles and the
other teeth.
crane, the assistant fits over the lower small iron axle an iron crank, which
projects from the upright beam a palm and two digits; the end of the little
axle is rectangular, and one and a half digits wide and one digit thick; it is
set into a similar rectangular hole in the crank, which is two digits long and a
little more than a digit wide. The crank is semi-circular, and one foot three
palms and two digits long, as many digits wide, and one digit thick. Its
handle is straight and round, and three palms long, and one and a half digits
thick. There is a hole in the end of the little axle, through which an iron
pin is driven so that the crank may not come off. The crane having four
drums, two of which are rundle-drums and two toothed-wheels, is more easily
moved than another having two drums, one of which has rundles and the
other teeth.
Many, however, use only a simple contrivance, the pivots of whose
crane-post turn in the same manner, the one in an iron socket, the other in a
ring. There is a crane-arm on the crane-post, which is supported by an
oblique beam; to the head of the crane-arm a strong iron ring is fixed,
which engages a second iron ring. In this iron ring a strong wooden lever-bar
is fastened firmly, the head of which is bound by a third iron ring, from which
hangs an iron hook, which engages the rings at the ends of the chains from
the dome. At the other end of the lever-bar is another chain, which, when
it is pulled down, raises the opposite end of the bar and thus the dome; and
when it is relaxed the dome is lowered.
crane-post turn in the same manner, the one in an iron socket, the other in a
ring. There is a crane-arm on the crane-post, which is supported by an
oblique beam; to the head of the crane-arm a strong iron ring is fixed,
which engages a second iron ring. In this iron ring a strong wooden lever-bar
is fastened firmly, the head of which is bound by a third iron ring, from which
hangs an iron hook, which engages the rings at the ends of the chains from
the dome. At the other end of the lever-bar is another chain, which, when
it is pulled down, raises the opposite end of the bar and thus the dome; and
when it is relaxed the dome is lowered.
zoom in
zoom out
zoom area
full page
page width
set mark
remove mark
get reference
digilib