This year marks the centennial of the invention that brought down Richard Nixon and caused complications for Bill Clinton: magnetic recording. It was 100 years ago that Valdemar Poulsen, an engineer with the Copenhagen Telephone Company, applied for a patent on his "telegraphone," a device that recorded the human voice magnetically on a steel piano wire.

Using the 1898 model of the Poulsen telegraphone (shown above), one could capture a 45-second message on a 100-meter wire wound on a rotating cylinder; the playback sound was free from the characteristic scratching of the phonograph. Poulsen's invention earned a grand prize at the Paris Exhibition of 1900, but a half-century would pass before magnetic recording found wide-spread application.