Portrait of the German experimental physicist Wilhelm Konrad Roentgen, 1845-1923, discoverer of X-rays. Roentgen was professor of physics at Wurzburg. While using a discharge tube (in which an electric discharge is passed through a gas at low pressure) in a darkened room, he noticed that a card coated with barium platinocyanide glowed when the tube was switched on. The effect was not blocked by an intervening wall, or even a thin sheet of metal. Roentgen termed this newly discovered phenomenon X-ray radiation, & suggested that it consisted of electromagnetic rays with a shorter wavelength than light. He was awarded the first Nobel Prize for physics, in 1901.