Sinking head

from The Collaborative International Dictionary of English v.0.48

Shrinking \Shrink"ing\,
   a. & n. from {Shrink}.
   [1913 Webster]

   {Shrinking head} (Founding), a body of molten metal connected
      with a mold for the purpose of supplying metal to
      compensate for the shrinkage of the casting; -- called
      also {sinking head}, and {riser}.
      [1913 Webster]

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]

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