Photograph of Wilhelm Conrad Roentgen (1845-1923) who discovered X-rays, for which he was awarded the Nobel Prize for Physics. He found that these rays pased through flesh, enabling the bones to be clearly seen. They showed as shadowed areas whereas metal objects would give an opaque shadow. The rays travelled in a straight-line and pased through card, but could be detected by photographic plate or fluorescent screen.
© Science Museum / Science & Society Picture Library