1wide and three digits
thick.
The sides of each pump-rod are covered and
protected by iron plates, which are held on by iron screws, so that a part
which has received damage can be repaired. In the “claws” is set a
small round axle, a foot and a half long and two palms thick. The ends are
encircled by iron bands to prevent the iron journals which revolve in the
iron bearings of the wood from slipping out of it.15 From this little axle
the wooden “claws” extend two feet, with a width and thickness of six
digits; they are three palms distant from each other, and both the inner and
outer sides are covered with iron plates. Two rounded iron keys two digits
thick are immovably fixed into the claws. The one of these keys per
forates the lower end of the first pump-rod, and the upper end of the second
pump-rod which is held fast. The other key, which is likewise immovable,
perforates the iron end of the first piston-rod, which is bent in a curve and
is immovable. Each such piston-rod is thirteen feet long and three digits
thick, and descends into the first pipe of each pump to such depth that its
disc nearly reaches the valve-box. When it descends into the pipe, the
water, penetrating through the openings of the disc, raises the leather, and
when the piston-rod is raised the water presses down the leather, and this
supports its weight; then the valve closes the box as a door closes an
entrance. The pipes are joined by two iron bands, one palm wide, one
outside the other, but the inner one is sharp all round that it may
fit into each pipe and hold them together. Although at the present time
pipes lack the inner band, still they have nipples by which they are joined
together, for the lower end of the upper one holds the upper end of the lower
one, each being hewn away for a length of seven digits, the former inside, the
latter outside, so that the one can fit into the other. When the piston-rod
descends into the first pipe, that valve which I have described is closed;
when the piston-rod is raised, the valve is opened so that the water can run
in through the perforations. Each one of such pumps is composed of two
lengths of pipe, each of which is twelve feet long, and the inside diameter is
seven digits. The lower one is placed in the sump of the shaft, or in a tank,
and its lower end is blocked by a round piece of wood, above which there are
six perforations around the pipe through which the water flows into it. The
upper part of the upper pipe has a notch one foot deep and a palm wide,
through which the water flows away into a tank or trough. Each tank is
two feet long and one foot wide and deep. There is the same number of
axles, “claws,” and rods of each kind as there are pumps; if there are three
pumps, there are only two tanks, because-the sump of the shaft and the drain
of the tunnel take the place of two. The following is the way this machine
draws water from a shaft. The wheel being turned raises the first pump
rod, and the pump-rod raises the first “claw,” and thus also the second
pump-rod, and the first piston-rod; then the second pump-rod raises the
second “claw,” and thus the third pump-rod and the second piston-rod;
then the third pump-rod raises the third “claw” and the third piston-rod,
protected by iron plates, which are held on by iron screws, so that a part
which has received damage can be repaired. In the “claws” is set a
small round axle, a foot and a half long and two palms thick. The ends are
encircled by iron bands to prevent the iron journals which revolve in the
iron bearings of the wood from slipping out of it.15 From this little axle
the wooden “claws” extend two feet, with a width and thickness of six
digits; they are three palms distant from each other, and both the inner and
outer sides are covered with iron plates. Two rounded iron keys two digits
thick are immovably fixed into the claws. The one of these keys per
forates the lower end of the first pump-rod, and the upper end of the second
pump-rod which is held fast. The other key, which is likewise immovable,
perforates the iron end of the first piston-rod, which is bent in a curve and
is immovable. Each such piston-rod is thirteen feet long and three digits
thick, and descends into the first pipe of each pump to such depth that its
disc nearly reaches the valve-box. When it descends into the pipe, the
water, penetrating through the openings of the disc, raises the leather, and
when the piston-rod is raised the water presses down the leather, and this
supports its weight; then the valve closes the box as a door closes an
entrance. The pipes are joined by two iron bands, one palm wide, one
outside the other, but the inner one is sharp all round that it may
fit into each pipe and hold them together. Although at the present time
pipes lack the inner band, still they have nipples by which they are joined
together, for the lower end of the upper one holds the upper end of the lower
one, each being hewn away for a length of seven digits, the former inside, the
latter outside, so that the one can fit into the other. When the piston-rod
descends into the first pipe, that valve which I have described is closed;
when the piston-rod is raised, the valve is opened so that the water can run
in through the perforations. Each one of such pumps is composed of two
lengths of pipe, each of which is twelve feet long, and the inside diameter is
seven digits. The lower one is placed in the sump of the shaft, or in a tank,
and its lower end is blocked by a round piece of wood, above which there are
six perforations around the pipe through which the water flows into it. The
upper part of the upper pipe has a notch one foot deep and a palm wide,
through which the water flows away into a tank or trough. Each tank is
two feet long and one foot wide and deep. There is the same number of
axles, “claws,” and rods of each kind as there are pumps; if there are three
pumps, there are only two tanks, because-the sump of the shaft and the drain
of the tunnel take the place of two. The following is the way this machine
draws water from a shaft. The wheel being turned raises the first pump
rod, and the pump-rod raises the first “claw,” and thus also the second
pump-rod, and the first piston-rod; then the second pump-rod raises the
second “claw,” and thus the third pump-rod and the second piston-rod;
then the third pump-rod raises the third “claw” and the third piston-rod,