Wilhelm Konrad Roentgen (1845-1923), German physicist and discoverer of X-rays. Roentgen was professor of physics at Wurzburg University in Germany. While using an electric discharge tube in a darkened room, he noticed that a card coated with barium platinocyanide glowed when the tube was switched on. The radiation causing this effect was not blocked by an intervening wall or even by a thin sheet of metal. Roentgen called his discovery X-rays and suggested they were a form of electromagnetic radiation akin to light but of shorter wavelength. He was awarded the first Nobel Prize for Physics in 1901 in recognition of his discovery.