Glass harmonica by rubbing glass or crystal goblets or bowls. The alternate instrument consisting of a set of wine glasses (usually tuned with water) is generally known in English as "musical glasses" or the "glass harp". When Benjamin Franklin invented his mechanical version of the instrument in 1761, he called it the armonica, based on the Italian word "armonia", which means "harmony". The unrelated free-reed wind instrument aeolina, today called the "harmonica", was not invented until 1821, sixty years later. The word "hydrodaktulopsychicharmonica" is also recorded, composed of Greek roots to mean something like "harmonica to produce music for the soul by
Glass harmonica produce a clear tone. Some attempted improvements on the armonica included adding keyboards, placing pads between the bowls to reduce sympathetic vibrations, and using violin bows. Another supposed improvement claimed in ill-informed post-period observations of non-playing instruments was to have the glasses rotate into a trough of water. However, William Zeitler put this idea to the test by rotating an armonica cup into a basin of water; the water has the same effect as putting water in a wine glass – it changes the pitch. With several dozen glasses, each a different diameter and thus rotating with a different depth,