Röntgen Centenary and Fifty Years of X-Rays

Abstract

WILHELM KONRAD RONTGEN was born on March 27, 1845. The discovery of X-rays was communicated by him to the Physico-Medical Society of Würtzburg in November 1895; a translation of his paper appeared in Nature of January 23, 1896. The present year thus marks the centenary of the birth of the discoverer, and the fiftieth anniversary of the epoch-making discovery with which his name is associated. It has sometimes been suggested that the discovery of X-rays was a happy accident; but there is no doubt, from the nature of his preparations, that Röntgen had, as he himself stated, set out to see whether the electric discharge through a gas at low pressure gave out any kind of 'invisible radiation' capable of detection outside the walls of the glass tube in which the discharge was taking place. The discharge tube (an ordinary Crookes tube of the cylindrical pattern, with a flat cathode at one end, and an anode tucked away in a side tube) had been wrapped in black paper, to cut off all the visible glow from the discharge, and a primitive fluorescent screen, consisting of a few crystals of barium platinocyanide on a piece of cardboard, lay handy on an adjacent bench—barium platinocyanide being a substance commonly used at the time to detect the invisible rays in the solar spectrum. On exciting the tube by means of a small induction coil to see if the light from the discharge was properly obscured by its black paper wrapper, Röntgen found that this was, indeed, the case; but he also noticed that his primitive fluorescent screen was now glowing brightly. The discovery of X-radiation had been made.