Change ringing
Change ringing is the art of ringing a set of tuned bells in a series of mathematical patterns called changes.
Change ringing differs from many other forms of campanology, in that players make no attempt to produce a conventional melody, but instead ring the bells in a set of permutations. Today, change ringing can be found all over the world, performed in a variety of media, but it remains most popular in English churches, where it was developed in the 17th century. Such a church's bell tower typically contains a set of a few large church bells, known as a ring of bells, rigged to swing freely for slightly more than one revolution. The considerable inertias involved mean that each bell usually requires its own ringer and can only speak about once every two seconds—the time for a full revolution.
Change ringing is also performed on handbells and on carillons (where the bells are fixed and the clappers are pulled over) though both of these instruments more commonly play melodies.