Still watcher

from The Collaborative International Dictionary of English v.0.48

Still \Still\, n. [Cf. OE. stillatorie. See {Still}, v., to
   distill.]
   1. A vessel, boiler, or copper used in the distillation of
      liquids; specifically, one used for the distillation of
      alcoholic liquors; a retort. The name is sometimes applied
      to the whole apparatus used in in vaporization and
      condensation.
      [1913 Webster]

   2. A house where liquors are distilled; a distillery.
      [1913 Webster]

   {Still watcher}, a device for indicating the progress of
      distillation by the density of the liquid given over.
      --Knight.
      [1913 Webster]