Lucy tuning is a
musical tuning based on two
musical intervals: the
octave, which is 2/1, and the
larger note, which is 1/2π octave, or slightly less than a
whole tone. The
lesser note is then defined so that two lesser notes plus five larger notes equal one octave. It was discovered by
Charles Lucy[?] in old writings of
John Harrison.
External reference: http://www.harmonics.com/lucy/