This article is about a musical term. See Perpetual motion for machines. For the album, See Perpetuum Mobile (album).

Perpetuum mobile (Latin), moto perpetuo (Italian), mouvement perpétuel literally meaning "perpetual motion", are terms applied to pieces of music, or parts of pieces, characterised by a continuous steady stream of notes, usually at a rapid tempo.

As a technique

A well-known example is the finale of Frederic Chopin's Piano Sonata No. 2 :

This figuration of rapid triplet quavers (eighth notes) continues for the duration of the movement.

Other examples include the second of Franz Schubert's Impromptus, D. 899, the finale of Carl Maria von Weber's Piano Sonata No. 1 , the final movement of Maurice Ravel's Sonata for violin and piano and the finale of Béla Bartók's Concerto for Orchestra.

As separate compositions

As a separate piece, a "Perpetuum Mobile" can be defined as a composition where (a large part of) the piece is intended to be repeated an (often not specified) number of times, without the "motion" of the melody being halted when a repeat begins. Canons are often intended to be performed in a moto perpetuo fashion (which, in that case, can be called canon perpetuus). In some cases the repeats of a "perpetuum mobile" piece are at a different pitch (while a modulation or a chord progression occurs during the repeatable part): some of the riddle canons of Bach's Das Musikalische Opfer are examples of this particular kind of Perpetuum Mobile/Canon Perpetuus.

19th century examples

Perpetuum mobile as a genre of separate musical compositions, was at the height of its popularity by the end of the 19th century. Such pieces would often be performed as virtuoso encores, in some cases increasing the tempo along the repeats. Such "perpetuum mobile" pieces include:

• Nicolò Paganini's Moto perpetuo Op. 11 (N° 6) for violin (most often performed with a rather insignificant "obligato" accompaniment);
• Felix Mendelssohn's Perpetuum mobile, opus 119, for piano;
• Johann Strauss II's Perpetuum Mobile: musikalischer Scherz for orchestra;
• The Flight of the Bumblebee by Nikolai Rimsky-Korsakov.

In the 20th century

20th century examples of the "Perpetuum Mobile" genre:

• Trois Mouvements perpétuels, a 1918 piano composition by Francis Poulenc.
• Arvo Pärt's orchestral Perpetuum mobile (1963).
• The string piece of music used by the British ABC Weekend Television to announce the start of its broadcasting hours.