Glass harmonica Franz Mesmer also played the armonica and used it as an integral part of his Mesmerism. An original Franklin armonica is in the archives at the Franklin Institute in Philadelphia, having been donated in 1956 by Franklin's descendants after "the children took great delight in breaking the bowls with spoons" during family gatherings. It is only placed on display for special occasions, such as Franklin's birthday. The Franklin Institute is also the home of the Benjamin Franklin National Memorial. A website has attempted to catalog publicly known Franklin-era glass armonicas. The Museum of Fine Arts, Boston has an early 19th-century
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,