What are anode rays?

Anode rays are streams of positive ions formed in low-pressure gases when high voltage is applied.

Also called canal rays, they were discovered by Goldstein. In a discharge tube, gas molecules lose electrons and become positive ions. These ions accelerate away from the anode through holes, forming visible beams. Their mass and charge depend on the gas, unlike electrons which are universal. Study of anode rays led to finding isotopes using mass spectrographs.