Agricola, Georgius, De re metallica, 1912/1950

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The fifth machine is partly like the whim, and partly like the third rag
and
chain pump, which draws water by balls when turned by horse power,
as
I will explain a little later.
Like this pump, it is turned by horse
power
and has two axles, namely, an upright one—about whose lower end,
which
decends into an underground chamber, there is a toothed drum—and a
horizontal
one, around which there is a drum made of rundles.
It has indeed
two
drums around its horizontal axle, similar to those of the big machine, but
smaller
, because it draws buckets from a shaft almost two hundred and forty
feet
deep.
One drum is made of hubs to which cleats are fixed, and
the
other is made of rundles; and near the latter is a wheel two
feet
deep, measured on all sides around the axle, and one foot wide; and
against
this impinges a brake,10 which holds the whim when occasion demands
that
it be stopped.
This is necessary when the hide buckets are emptied
after
being drawn up full of rock fragments or earth, or as often as water
is
poured out of buckets similarly drawn up; for this machine not only
raises
dry loads, but also wet ones, just like the other four machines which
I
have already described.
By this also, timbers fastened on to its winding­
chain
are let down into a shaft.
The brake is made of a piece of wood one
foot
thick and half a foot long, projecting from a timber that is suspended
by
a chain from one end of a beam which oscillates on an iron pin, this in
turn
being supported in the claws of an upright post; and from the other end
of
this oscillating beam a long timber is suspended by a chain, and from this
long
timber again a short beam is suspended.
A workman sits on the short
beam
when the machine needs to be stopped, and lowers it; he then inserts
a
plank or small stick so that the two timbers are held down and cannot be
raised
.
In this way the brake is raised, and seizing the drum, presses it
so
tightly that sparks often fly from it; the suspended timber to which
the
short beam is attached, has several holes in which the chain is

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