Wilhelm Röntgen
The N-ray affair occurred shortly after a series of major breakthroughs in experimental physics. Victor Schumann discovered vacuum ultraviolet radiation in 1893, Wilhelm Röntgen discovered X-rays in 1895, Henri Becquerel discovered radioactivity in 1896, and, in 1897, J. J. Thomson discovered electrons, showing that they were the constituents of cathode rays. This created an expectation within the scientific community that other forms of radiation might be discovered.