glass harmonica

Musical instrument based on the principle of playing a wine glass with a wet finger. It consists of a graded series of glass bowls nested on a spindle and resting in a trough partly filled with water. Rotated by a foot pedal, it emits pure tones of unchanging intensity when touched either by the fingers or mechanically. It was devised by Benjamin Franklin; Mozart, Beethoven, and Schubert all wrote pieces for it.