A small metal cylinder is an important part of many music boxes. The cylinder has "pins" sticking up from it. A spring makes the cylinder turn around. As it turns, the pins strike the teeth of a metal "comb." Each tooth gives off a certain note when it is struck. As the teeth are struck, a tune is played. Of course, the pins must be in exactly the right place on the cylinder. A music box with a cylinder has its tunes buüt in.
Some music boxes have metal disks instead of cylinders. Little tabs projecting downward from the disk strike the comb beneath as the disk turns round. Before the phonograph was invented, music boxes were made with disks that could be changed like phonograph records.
Music boxes have a tinkly sound. And sometimes it is hard to tell what tune is being played. But many people think that music boxes are fun. Collecting music boxes, in fact, is a rather common hobby.
