Roentgen, Wilhelm: Wilhelm Conrad Rontgen (1845-1923), German-born, Dutch-educated physicist who first observed and documented X-rays on November 8, 1895. He made this seminal discovery by accident while experimenting with a set of cathode ray instruments. He was surprised to find a flickering image cast by his instruments separated from them by some distance. He knew that the image he saw was not being cast by the cathode rays (now known as beams of electrons) as they could not penetrate air for any significant distance.
A week later, he took an X-ray photograph of his wife's hand which clearly revealed her wedding ring and her bones. The photograph electrified the general public and aroused great scientific interest in the new form of radiation. Roentgen called it "X" to indicate it was an unknown type of radiation. The name stuck, although (over Roentgen's objections), many of his colleagues suggested calling them Roentgen rays. They are still occasionally referred to as Roentgen rays in German-speaking countries.
Roentgen did notable research in many fields of physics including the specific heats of gases, the thermal conductivity of crystals, the electrical and other characteristics of quartz, the influence of pressure on the refractive indices of various fluids, the modification of the planes of polarised light by electromagnetic influences, the variations in the functions of the temperature and the compressibility of water and other fluids, and the phenomena accompanying the spreading of oil drops on water. But when Roentgen received the Nobel Prize in Physics in 1901, the first Nobel Prize ever awarded in Physics, it was "in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him."