Circulating temperament
A circulating temperament is a periodic scale with the property that for at least one interval class, all of the intervals in the class can be regarded as approximations of some targeted interval (such as a fixed just interval, or a generator of an edo), but which is not an equal temperament. In the best known examples, the interval approximated is a fifth and the scale has twelve notes to an octave.
One of the advantages of these tunings, is that because they are not quite equal, each chord (or key) has a slightly different character because the interval sizes have changed slightly.
Types
A circulating temperament may be classified by method as follows: