plucker tube

from The Collaborative International Dictionary of English v.0.48

Geissler tube \Geis"sler tube`\ (Elec.)
   A glass tube provided with platinum electrodes, and
   containing some gas under very low tension, which becomes
   luminous when an electrical discharge is passed through it;
   -- so called from the name of a noted maker in germany. It is
   called also {Pl["u]cker tube}, from the German physicist who
   devised it.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Plucker tube \Pl["u]ck"er tube\ [So named after Julius
   Pl["u]cker, a German physicist.] (Physics)
      (a) A vacuum tube, used in spectrum analysis, in which the
          part through which the discharge takes place is a
          capillary tube, thus producing intense incandescence
          of the contained gases.
      (b) Crookes tube.
          [Webster 1913 Suppl.]

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