An instrument devised by Benjamin Franklin on the principal of vibrating wine glasses ( idiophone). Franklin's instrument consisted of a number of glass bowls without stems which rotated in a tray of water. The performer gently touched the rims of the revolving glass bowls thus setting them to vibrate. The pitch varied according to the size of the bowl. Wolfgang Amadeus Mozart, among others, wrote several compositions for the Glass Armonica.See also Glasharfe; Glass harp; glass harmonica; and musical glasses.