What are Canal Rays? Positive rays are also called Canal rays. Eugene Goldstein, in 1886, discovered positive rays in discharge tube. Canal rays Discharge Tube Experiment: He used a discharge tube having perforated cathode. Goldstein noted that glow is produced on the wall opposite to anode i.e on the back of cathode. These raysCanal Rays Discovery ,Experiment and Properties |Proton Discovery – Atomic Structure