The pump is constructed from an
endless rope or chain which passes
over a pulley, down into the well,
and back up through a pipe. By
securing washers to the rope or
chain, water is drawn up the pipe.
Obviously the pipe end must be
below the water surface and the rope
(or chain) and its attached washers
must not touch the bottom of the well
otherwise they would stir up mud. In
practical terms, this means that there
must be a water depth of at least half
a metre at the bottom of the well.