Original manuscript of Dr Heinrich Hertz, 1888.
© Science Museum / Science & Society Picture Library
Manuscript entitled 'Uber Strahlen elektrischer Kraft'. German physicist Heinrich Rudolf Hertz (1857-1894) discovered 'Hertzian waves', (electromagnetic waves) and found that they behave like light waves except for their wavelength. He was reputedly the first man to broadcast and receive radio waves and the unit of frequency of radio waves is named after him.