Sinking pump

from The Collaborative International Dictionary of English v.0.48

Sinking \Sink"ing\,
   a. & n. from {Sink}.
   [1913 Webster]

   {Sinking fund}. See under {Fund}.

   {Sinking head} (Founding), a riser from which the mold is fed
      as the casting shrinks. See {Riser}, n., 4.

   {Sinking pump}, a pump which can be lowered in a well or a
      mine shaft as the level of the water sinks.
      [1913 Webster]