The Discovery

• 1895 carried out his investigations on the phenomenon of cathode rays
• Roentgen took a vacuum tube, that he used for cathode ray experiments  and covered it in thin black cardboard and placed it in a darkened room. 
• A bright glow was seen on a screen covered with florescent lights.
• He realized that the florescent was caused by an agent which could infiltrate from within the vacuum tube through the black cardboard.
• He called the agent X-rays