The Beyer Glass-cord (a/k/a glasscord) is a keyboard musical instrument that uses wound hammers to play glass bars, somewhat like a celesta or keyboard glockenspiel. The story of it is as follows, which is culled from several scholarly sources:
Benjamin Franklin, when he came to England in 1757, became interested in glass instruments, some of which created sound using glasses filled with varying levels of water being struck. This type was unwieldy to carry. In the winter of 1784/85, a Parisian physician named Beyer approached Franklin with an idea for constructing a kind of glass xylophone, played by means of mechanical hammers controlled by a keyboard. Franklin must have been intrigued by the idea, and gave Beyer his endorsement. Beyer presented a prototype to the Académie des Sciences in the spring of 1785, and received an enthusiastic reception. He then reminded Franklin of his promise to give a name to what the inventor had been calling simply 'the instrument'. Ever frugal, Franklin found a use for his formerly abandoned name, christened it the 'glasschord', and purchased one to take home with him to Philadelphia. Thomas Jefferson saw the instrument a week before Franklin left France and found it charming. Its tone was exceptionally sweet, he said, and Jefferson only regretted that its three-octave range was too short. A glasscord was one of the few instruments found in Benjamin Franklin's estate. An inventory of Franklin's instruments at the time of his death includes a viola da gamba, bells, harpsichord, glass armonica, spinet, Chinese gong, and a "Glassichord". The reader will recall that the 'glassichord' was the initial name that Franklin gave to the armonica. Yet, clearly if the armonica has already been listed in the inventory, the person listing the inventory wouldn't have listed the same instrument with an additional name. Thus the glassichord must be a different musical instrument altogether. Essentially, the instrument was designed and built in France for the Aristocracy. Mozart composed music for such an instrument in 1791, for a performance by the blind musician Marianne Kirchgessner.
This particular glasscord was purchased in Paris from Alain Vian for the Hans Adler keyoard collection in 1959. Permission to export this rarity from France was granted by Musee du Louvre, which first checked that one somewhat similar instrument was left in France, where a different type of glasscord belonged to the Comte de Briqueville. Hans Adler had only seen two others, one in a private collection in France and one in the musical instrument museum in Vienna. Their fragility accounts for their rarity. Some repairs have been effected, and a number of glass bars replaced. Most of the glass bars feature a string that is woven through the respective tops of the bars. The hammers are wound with linen ribbon and are the size of medium-sized olives. The cabinet depicts excellent woodwork craftsmanship of that time. The keys still operate effectively, and it can be played. It produces a sound somewhat like a glass armonica and celesta, both delicate and sweet, as is to be expected. The instrument is demarcated "Glass~cord de Beyer 1786", with the dash/hyphen/tilde being the wavy type.