Benjamin Franklin invented the glass armonica in 1761, using rotating glass bowls rubbed by the fingers.
Franklin developed the instrument after hearing glass musical glasses played in London. Instead of arranging separate glasses, he mounted nested glass bowls on a spindle. A foot treadle rotated the spindle while the performer touched the bowl rims with moistened fingers.
The bowls were tuned to different pitches, allowing one performer to play melodies and chords. The instrument became fashionable in late-eighteenth-century Europe and was used by composers including Mozart and Beethoven.
It is often confused with a glass harp, which uses individual glasses rather than Franklin’s mechanically rotated bowls. The name “armonica” comes from Franklin’s preferred Italian-style spelling of “harmony.”