Beginning in 1921, with an article serialized in "The Freeman", an Irish cultural journal, Cowell popularized the term "tone cluster". While he did not coin the phrase, as is often claimed, he appears to have been the first to use it with its current meaning. During the 1920s and 1930s, Cowell toured widely through North America and Europe, playing his own experimental works, many built around tone clusters. In addition to "The Tides of Manaunaun", "Dynamic Motion", and its five "encores"—"What's This" (1917), "Amiable Conversation" (1917), "Advertisement" (1917), "Antinomy" (1917, rev. 1959; frequently misspelled "Antimony"), and "Time Table" (1917)—these include "The Voice of Lir" (1920), "Exultation" (1921), "The Harp of Life" (1924), "Snows of Fujiyama" (1924), "Lilt of the Reel" (1930), and "Deep Color" (1938). "Tiger" (1930) has a chord of 53 notes, probably the largest ever written for a single instrument until 1969. Along with Ives, Cowell wrote some of the first large-ensemble pieces to make extensive use of clusters. "The Birth of Motion" ( 1920), his earliest such effort, combines orchestral clusters with glissando. "Tone Cluster," the second movement of Cowell's Concerto for Piano and Orchestra (1928, prem. 1978), employs a wide variety of clusters for the piano and each instrumental group (). From a quarter-century later, his Symphony No. 11 (1953) features a sliding chromatic cluster played by muted violins.