Oxford University Press's
Academic Insights for the Thinking World
X-ray diffraction by crystalline powders is one of the most powerful and most widely used methods for analyzing matter. It was discovered just one hundred years ago, independently, by Paul Scherrer and Peter Debye in Göttingen, Germany, and by Albert Hull at the General Electric Laboratories, Schenectady, USA.
The International Year of Light provides a good opportunity to revisit the early studies on the optical properties of X-rays. X-rays were discovered by W. C. Röntgen on the evening of 8 November 1895 while he was redoing some of Hertz’s experiments on cathode rays. By the end of the year, even before informing the world of his discovery, he had observed the basic properties of X-rays: like light, they propagate as straight lines and are diffused by turbid media, but are not deflected by a prism, nor refracted or reflected by matter; they pass through bodies, as shown by the radiograph of his wife’s hand.