A piece of musical mechanism produced at equal intervals of time by the strokes of a hammer against a series of bells. This is effected by means of a chime-barrel, which is something of the nature of a barrel to an organ. It is a cylinder of brass in small clocks, or of wood in church clocks, which gives motion to the hammers that strike the bells, and produce a change or tune by means of pegs inserted into certain points of its circumference at measured intervals.