Joseph John Thomson

“ From the points of the triangle stream pencils of luminosity showing the characteristic red colour of the positive rays in helium, while the middle points of the sides are the origin of streams of greenish luminosity, the colour of the path of the cathode rays through helium. The difference In the character of the rays is also made evident by bringing a small magnet near the discharge tube; the green rays are visibly deflected by the magnet but no appreciable effect is produced on the red rays. ”