Definition of canal rays in English:

canal rays

noun

Physics
historical
  • Streams of positive ions which are produced in a high-vacuum discharge tube and move towards the cathode, some of them passing through openings in it.

Origin

Late 19th century; earliest use found in Journal of Physical Chemistry. After German Kanalstrahlen, plural noun; so called on account of the openings in the cathode through which the ions pass.