The invisible made visible

This article focuses on the early history of X-rays. It argues that, during the first years after their discovery in 1895 by German physicist Wilhelm Conrad Röntgen, they were regarded as a technological attraction and a visual medium. While their application in medical practice was not yet fully established, the possibility of seeing into the realm of the invisible encouraged pioneers of this technology to actively exploit their visual powers. By using a media-history framework, and relying on primary and secondary sources in English, German, French, and Italian, the article takes into account three aspects of the rays' early display: its character of technological attraction; its association with photography; and its connection to beliefs in the supernatural and the occult.