In the later part of the 1800s, an English physicist, William Crookes, produced one of the first prototypes of a cathode ray tube, as shown above. The cathode ray tube consists of a glass container that has been evacuated of gases. On either end of the evacuated tube, a metal electrode is placed. At the one end, the electrode is referred to as a cathode and the electrode at the other end is called the anode. When an electrical charge is applied to the cathode, cathode rays are projected toward the anode. One can seen the cathode rays in the picture above (the illuminated beam inside the tube).
