The preludes, many of which are very brief (some consisting of simple statements and developments of a single theme or figure), were described by Schumann as "the beginnings of studies". Inspired by J.S. Bach's The Well-Tempered Clavier, Chopin's preludes move up the circle of fifths (rather than Bach's chromatic scale sequence) to create a prelude in each major and minor tonality. The preludes were perhaps not intended to be played as a group, and may even have been used by him and later pianists as generic preludes to others of his pieces, or even to music by other composers, as Kenneth Hamilton suggests: he has noted a recording by Ferruccio Busoni of 1922, in which the Prelude Op. 28 No. 7 is followed by the Étude Op. 10 No. 5.