A music box is a 19th century automatic musical instrument

Musical instrument

A musical instrument is a device created or adapted for the purpose of making musical sounds. In principle, any object that produces sound can serve as a musical instrument—it is through purpose that the object becomes a musical instrument. The history of musical instruments dates back to the...

 that produces sounds by the use of a set of pin

Pin

A pin is a device used for fastening objects or material together.Pin may also refer to:* Award pin, a small piece of metal or plastic with a pin attached given as an award for some achievement...

s placed on a revolving cylinder

Cylinder (geometry)

A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...

 or disc so as to pluck the tuned teeth of a steel comb

Comb

A comb is a toothed device used in hair care for straightening and cleaning hair or other fibres. Combs are among the oldest tools found by archaeologists...

. They were developed from musical snuff boxes of the 18th century and called carillons à musique. Some of the more complex boxes also have a tiny drum

Drum

The drum is a member of the percussion group of musical instruments, which is technically classified as the membranophones. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a shell and struck, either directly with the player's hands, or with a...

 and small bells

Bell (instrument)

A bell is a simple sound-making device. The bell is a percussion instrument and an idiophone. Its form is usually a hollow, cup-shaped object, which resonates upon being struck...

, in addition to the metal comb. Note the tone of a music box is unlike that of any other musical instrument (but it is best described as somewhere between the timbres of an mbira

Mbira

In African music, the mbira is a musical instrument that consists of a wooden board to which staggered metal keys have been attached. It is often fitted into a resonator...

).
The original snuff boxes were tiny containers which could fit into a gentleman's waistcoat pocket.