The componium was a mechanical musical instrument constructed in 1821 by Dietrich Nikolaus Winkel

Dietrich Nikolaus Winkel

Dietrich Nikolaus Winkel was the inventor of the first successful metronome. He also invented the componium, an automatic instrument that could make endless variations on a musical theme....

 (Lippstatt, Germany, 1773 - Amsterdam, Netherlands, 1826) that composed novel music. It was an automatic organ

Mechanical organ

A mechanical organ is an organ that is self playing, rather than played by a musician.Usually, mechanical organs are pipe organs although some instruments were built using reeds similar to those found in a harmonium. Since the 1950s, some instruments have been built using electronics to generate...

 consisting of two barrels that revolve simultaneously. The barrels take turns performing two measures of randomly chosen music while the other pauses. The componium's compositional power is thus limited to new combinations of the music provided in its barrels.
This Instrument was a copy of Johann Nepomuk Mälzel

Johann Nepomuk Mälzel

Johann Nepomuk Maelzel [or Mälzel] was an inventor, engineer, and showman, best known for manufacturing a metronome and several music automatons, and displaying a fraudulent chess machine.-Life and work:...

s panharmonicon

Panharmonicon

The Panharmonicon was a musical instrument invented in 1805 by Johann Nepomuk Mälzel, a contemporary and friend of Beethoven. Beethoven apparently composed his piece "Wellington's Victory" to be played on this behemoth mechanical orchestral organ to commemorate Arthur Wellesley's victory over the...

.

The componium, in a rather bad shape now, is in the collection of the Brussels Museum of Instruments.