What unique instrument was invented by Benjamin Franklin that appears in "Carnival of the Animals"?

The unique instrument invented by Benjamin Franklin that appears in "Carnival of the Animals" is the glass harmonica. This instrument, also known as the glass harp, consists of a series of glass bowls or goblets of varying sizes mounted on a spindle that can be played by rubbing the rims with wet fingers, producing musical tones.

Franklin created the glass harmonica in 1761, inspired by the sounds produced when glass vessels are rubbed together. Its ethereal and delicate sound has captivated musicians and listeners alike, making it a distinctive addition to various musical compositions, including "Carnival of the Animals" by Camille Saint-Saëns. In this piece, the glass harmonica is often associated with themes of fantasy and playfulness, fitting perfectly with the overall whimsical nature of the composition.

Other instruments mentioned in the options do not share this unique origin and sound quality, focusing instead on more traditional or widely used instruments in classical settings.