Musical Box, a case enclosing mechanism so constructed as to play tunes automatically. The principle of the mechanism is the same as that of the barrel or hand organ, and of the machinery which is used for the chimes of bells in church towers. The use of machines for making mechanical music is almost coeval with the invention of clocks; but musical boxes proper were not introduced much before the latter half of the 18th century. Among the earliest made were small ones to be worn as a charm or seal, pendent from the watch chain; and from this insignificant beginning has grown the modern musical box, capable of almost every musical effect and of playing from one to more than 100 tunes. The principal parts of the mechanism are the comb, the cylinder, and the fly or regulator. The comb is a steel board with many tongues, arranged like the teeth of a comb. The cylinder, which is usually brass, is fitted with small steel pins or points representing the notes of the tune to be played. This is moved forward or backward by mechanism into a proper position to act on the comb, when it revolves and its pins raise and let fall the teeth, producing musical tones.

As the notes must necessarily follow in rapid succession, it is impossible to make one tooth of the comb produce the requisite number without striking on the following pin; therefore, when needed, there are two, three, or four teeth of the comb of the same tone or pitch placed beside each other, which are struck by pins arranged side by side instead of behind each other, thus permitting the rapid recurrence of the same note. The time in which the cylinder makes its revolutions depends upon the train of wheels and pinions leading to the fly. In all the larger music boxes the fly or regulator is adjustable, the wings which impinge against the air being capable of limited extension and contraction, thus retarding or accelerating the rate of revolution of the cylinder. The tones of the tongues are regulated by their length and thickness; the shorter they are, the quicker are the vibrations and the higher in the scale is the pitch. The vibrations of the long teeth are retarded by masses of lead attached to them, and underneath them are placed little dampers made of spring wire for the purpose of checking the vibrations when too long.

Various attachments or accompaniments, such as bells, drums, and castanets, are often applied to musical boxes, and different effects are produced according to the arrangement of the music. In respect to these effects musical boxes are called mandolines, expres-sives, quatuors, organocleides, piccolos, etc. Some have a combination of reeds and pipes, and are called flutes, celestial voices, or harmo-niphones. The musical clocks of the Black Forest, and the musical boxes of Prague and of Ste. Susanne in France, are largely exported. The centres of the manufacture, in its present state of mechanical perfection, are Geneva and Ste. Croix, in the Pays de Vaud, Switzerland.