The 'World's Most Dangerous Instrument': The Glass Armonica Invented By Benjamin Franklin

June 5, 2023

The glass armonica, also known as a glass harmonica or simply armonica, is a musical instrument that produces sound by rubbing glass or crystal bowls or goblets with wet fingers.

It was invented by Benjamin Franklin in 1761.

Credit: PBS / @PBS on YouTube

The instrument consists of a series of glass or crystal bowls or goblets of varying sizes, mounted horizontally on a spindle. The bowls are arranged in order of size, with the largest bowl on one end and the smallest on the other.

Franklin came up with the idea after attending a concert in Cambridge. The performer was rubbing the rims of wine glasses to produce musical notes.

Franklin thought that was inefficient. Why move your arms when you can move the glasses?

So, he hired a London glassmaker to construct 36 bowls to specific thicknesses and sizes. He mounted the bowls horizontally on a spindle with the largest bowl on one end and the smallest on the other.

In this way the musician can play the glass bowls like a keyboard.

Watch a demonstration below.

The World's Most Dangerous Instrument?

The glass armonica became popular during the late 18th and early 19th centuries. Mozart and Beethoven both composed chamber pieces for it.

But by the 1820s, it was nearly a forgotten instrument amid fears that it had the power to drive the listener insane.

Some armonica players became ill and had to stop playing the instrument. They complained of muscle spasms, nervousness, cramps, and dizziness. A few listeners were also subject to ill effects. The instrument was actually banned in a few towns.

"Some people thought that the high-pitched, ethereal tones invoked the spirits of the dead, had magical powers, or drove listeners mad," the Franklin Institute said. "Others thought that lead from the crystal bowls or paint was absorbed into the musicians' fingers when they touched the glass, causing sickness."

One example of alleged effects from playing the glass harmonica was noted by German musicologist Johann Friedrich Rochlitz.

"The armonica excessively stimulates the nerves, plunges the player into a nagging depression and hence into a dark and melancholy mood that is apt method for slow self-annihilation."

However, no explanation or proof was ever really given to any of these claims. Franklin himself ignored all of the controversy and continued to play the instrument until the end of his life.