What is the cathode ray? How was the Nature of cathode rays determined?

Cathode rays are streams of electrons observed in discharge tubes. In 1897, British physicist J. J. Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, which was later named the electron. Cathode-ray tubes (CRTs) use a focused beam of electrons deflected by electric or magnetic fields to render an image on a screen.

what is the question here. i think you messed up.