This Day in History: , German Scientist Discovers X-Rays .br November 8, 1895.br Wilhelm Conrad Rontgen's , discovery of X-rays happened accidentally as he conducted a test on cathode rays.br He noticed a glow on a screen br coated with chemicals. br Rontgen called the rays br that caused the glow X-rays.br After conducting more experiments, Rontgen discovered that X-rays could pass through human flesh, but not harder substances such as bone.br He also learned that they could br be photographed. The discovery br was hailed as a medical miracle.br X-rays were first used on a br battlefield during the Balkan War in 1897.