a scale composed entirely of whole tones, six to the octave. The scale was used as a comic device by W. A. Mozart in the sextet A Musical Joke (1787), and it is encountered from time to time in romantic music. M. I. Glinka used the whole-tone scale in Ruslan and Liudmila as the motif identifying Chernomor (the “Chernomor scale”); the scale has also been used by other Russian composers, such as A. S. Dargomyzhskii and A. P. Borodin, and by French impressionist composers. As the expression of a unique “augmented chord harmony,” the whole-tone scale came to be used as the harmonic foundation of individual sections of a work or occasionally of entire compositions, for example, the prelude Voiles by C. Debussy. By the mid-20th century, the expressive possibilities of the whole-tone scale had essentially been exhausted, and it is now used very rarely.