"Canal rays" were produced in experiments by a German scientist, Eugen Goldstein, in 1886. Goldstein used a gas discharge tube which had perforated cathodes. A "ray" was produced in the holes (canals) in the cathode and traveled in a direction opposite to the "cathode ray." In 1907 a study of how this "ray" was deflected in a magnetic field, revealed that the particles making up the ray were of varying mass. The lightest, formed when there was a little hydrogen in the tube, was calcuated to be 1837 times as massive as an electron.

From: Chemistry for Changing Times by John W. Hill, Burgess Publishing Company, 1972