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In the mid-1700s, while serving as a delegate for the American colonies in Europe, Benjamin Franklin experienced a popular musical performance — singing glasses. Intrigued by the beautiful sound of a wet finger on glass, Franklin developed an instrument known as a “glass armonica” in 1761. Working with a glassblower in London, Franklin altered the thickness of glass bowls, interlocked along a rod, in order to produce a range of pitches.

Far from being one of Franklin’s odder ideas (like his failed phonetic alphabet), the glass armonica was an 18th-century sensation. Some of the era’s greatest composers, including Wolfgang Amadeus Mozart and Ludwig van Beethoven, wrote music for the instrument. However, it was largely forgotten by the 1820s — many musicians complained of dizziness and other symptoms after playing it, with some blaming lead poisoning or the instrument’s vibrations as the cause. Today, a few musicians still practice the subtle, ethereal art of the glass armonica.