String instrument strings, or play them by rolling the bell of a brass instrument such as a trombone on the array of strings. However, these are relatively rarely used special techniques. Other keyed string instruments, small enough for a strolling musician to play, include the plucked autoharp, the bowed nyckelharpa, and the hurdy-gurdy, which is played by cranking a rosined wheel. Steel-stringed instruments (such as the guitar, bass, violin, etc.) can be played using a magnetic field. An E-Bow is a small hand-held battery-powered device that magnetically excites the strings of an electric string instrument to provide a sustained, singing tone reminiscent
The Hurdy Gurdy Man Gurdy Man" were both released as singles well before the album was released. The recording sessions for the album are purported to have included future Led Zeppelin members Jimmy Page and John Paul Jones. Page was in The Yardbirds at the time and was actively looking to rebuild that band. The album credits John Bonham for percussion on the song and Clem Cattini as the drummer. All tracks credited to Donovan Leitch. According to BMI, "A Sunny Day" and "The River Song" were collaborations with David J. Mills, but "Tangier" was written solely by Mills under its original title of