1much water, to drain it by the rag and chain pump or to
bring it up in
water-bags.
water-bags.
Enough, then, of the first sort of pumps.
I will now explain the other,
that is the pump which draws, by means of pistons, water which has been
raised by suction. Of these there are seven varieties, which though they
differ from one another in structure, nevertheless confer the same benefits
upon miners, though some to a greater degree than others. The first pump
is made as follows. Over the sump is placed a flooring, through which a
pipe—or two lengths of pipe, one of which is joined into the other—are let
down to the bottom of the sump; they are fastened with pointed iron clamps
driven in straight on both sides, so that the pipes may remain fixed. The
lower end of the lower pipe is enclosed in a trunk two feet deep; this trunk,
hollow like the pipe, stands at the bottom of the sump, but the lower opening
of it is blocked with a round piece of wood; the trunk has perforations
round about, through which water flows into it. If there is one length of
pipe, then in the upper part of the trunk which has been hollowed out there is
enclosed a box of iron, copper, or brass, one palm deep, but without a bottom,
and a rounded valve so tightly closes it that the water, which has been drawn
up by suction, cannot run back; but if there are two lengths of pipe, the
box is enclosed in the lower pipe at the point of junction. An opening or a
spout in the upper pipe reaches to the drain of the tunnel. Thus the work
man, eager at his labour, standing on the flooring boards, pushes the piston
down into the pipe and draws it out again. At the top of the piston-rod is a
hand-bar and the bottom is fixed in a shoe; this is the name given to the
leather covering, which is almost cone-shaped, for it is so stitched that it is
tight at the lower end, where it is fixed to the piston-rod which it surrounds,
but in the upper end where it draws the water it is wide open. Or else an
iron disc one digit thick is used, or one of wood six digits thick, each of which
is far superior to the shoe. The disc is fixed by an iron key which pene
trates through the bottom of the piston-rod, or it is screwed on to the
rod; it is round, with its upper part protected by a cover, and has five or
six openings, either round or oval, which taken together present a star-like
appearance; the disc has the same diameter as the inside of the pipe,
so that it can be just drawn up and down in it. When the workman draws
the piston up, the water which has passed in at the openings of the disc,
whose cover is then closed, is raised to the hole or little spout, through which
it flows away; then the valve of the box opens, and the water which has
passed into the trunk is drawn up by the suction and rises into the pipe;
but when the workman pushes down the piston, the valve closes and allows
the disc again to draw in the water.
that is the pump which draws, by means of pistons, water which has been
raised by suction. Of these there are seven varieties, which though they
differ from one another in structure, nevertheless confer the same benefits
upon miners, though some to a greater degree than others. The first pump
is made as follows. Over the sump is placed a flooring, through which a
pipe—or two lengths of pipe, one of which is joined into the other—are let
down to the bottom of the sump; they are fastened with pointed iron clamps
driven in straight on both sides, so that the pipes may remain fixed. The
lower end of the lower pipe is enclosed in a trunk two feet deep; this trunk,
hollow like the pipe, stands at the bottom of the sump, but the lower opening
of it is blocked with a round piece of wood; the trunk has perforations
round about, through which water flows into it. If there is one length of
pipe, then in the upper part of the trunk which has been hollowed out there is
enclosed a box of iron, copper, or brass, one palm deep, but without a bottom,
and a rounded valve so tightly closes it that the water, which has been drawn
up by suction, cannot run back; but if there are two lengths of pipe, the
box is enclosed in the lower pipe at the point of junction. An opening or a
spout in the upper pipe reaches to the drain of the tunnel. Thus the work
man, eager at his labour, standing on the flooring boards, pushes the piston
down into the pipe and draws it out again. At the top of the piston-rod is a
hand-bar and the bottom is fixed in a shoe; this is the name given to the
leather covering, which is almost cone-shaped, for it is so stitched that it is
tight at the lower end, where it is fixed to the piston-rod which it surrounds,
but in the upper end where it draws the water it is wide open. Or else an
iron disc one digit thick is used, or one of wood six digits thick, each of which
is far superior to the shoe. The disc is fixed by an iron key which pene
trates through the bottom of the piston-rod, or it is screwed on to the
rod; it is round, with its upper part protected by a cover, and has five or
six openings, either round or oval, which taken together present a star-like
appearance; the disc has the same diameter as the inside of the pipe,
so that it can be just drawn up and down in it. When the workman draws
the piston up, the water which has passed in at the openings of the disc,
whose cover is then closed, is raised to the hole or little spout, through which
it flows away; then the valve of the box opens, and the water which has
passed into the trunk is drawn up by the suction and rises into the pipe;
but when the workman pushes down the piston, the valve closes and allows
the disc again to draw in the water.
The piston of the second pump is more easily moved up and down.
When
this pump is made, two beams are placed over the sump, one near the right side
of it, and the other near the left. To one beam a pipe is fixed with iron clamps;
to the other is fixed either the forked branch of a tree or a timber cut out at
the top in the shape of a fork, and through the prongs of the fork a round
hole is bored. Through a wide round hole in the middle of a sweep passes
this pump is made, two beams are placed over the sump, one near the right side
of it, and the other near the left. To one beam a pipe is fixed with iron clamps;
to the other is fixed either the forked branch of a tree or a timber cut out at
the top in the shape of a fork, and through the prongs of the fork a round
hole is bored. Through a wide round hole in the middle of a sweep passes