It was November 1895. Dr. Wilhelm Roentgen, working alone in his laboratory, was doing an experiment, passing electric current through a glass tube from which the air had been pumped out.
Scientists had discovered that the device, called a Crookes tube, produced a beam of flowing electrons, a cathode ray, which made the tube glow. To further study cathode rays, Roentgen darkened the room and wrapped the Crookes tube in black cardboard. Then he turned on the electricity.
The Mystery Light
No light escaped through the
