musical instrument consisting of a set of graduated, tuned glass bowls sounded by the friction of wetted fingers on their rims. It was invented by Benjamin Franklin and was derived from the verillon (musical glasses), a set of glasses, holding different amounts of water and thus yielding different notes, placed on a soundboard and rubbed by moistened fingers or, rarely, struck with rods. The German composer Christoph Willibald Gluck performed his concerto for this instrument in London in 1746.