Joshua C. Stoddard of Worcester, Massachusetts patented the calliope on October 9, 1855, though his design echos previous concepts, such as an 1832 instrument called a "steam trumpet," later known as a train whistle. In 1851, William Hoyt of Dupont, Indiana claimed to have conceived of a device similar to Stoddard's calliope, but he never patented it. Later, an employee of Stoddard's American Music, Arthur S. Denny, attempted to market an "Improved Kalliope" in Europe, but it did not catch on. In 1859, he demonstrated this instrument in Crystal Palace, London. Unlike other calliopes before or since, Denny's Improved Kalliope let the player control the steam pressure, and therefore the volume of the music, while playing.