Crystal flute by Claude Laurent, Paris, ca. 1817 (NMM 10103). The crystal (glass) flute was invented by Claude Laurent (d. 1848), who first patented the concept in 1806 and won a silver medal that year at the Industrial Exposition in Paris. Popular with world leaders, Laurent flutes were owned not only by James Madison, the fourth President of the United States, but also by Emperor Napoleon I of France, King Louis Napoleon of Holland, King Joseph Bonaparte of Spain, and Emperor Franz I of Austria. This showpiece, with silver ferrules and four silver keys topped with yellow, mirrored-back-glass jewels, survives in remarkable condition. Although glass is more stable than wood and does not react to temperature and humidity changes, glass is easily damaged, so Laurent's instruments, although they played well, were deemed impractical. Only about 124 of them survive, primarily in the hands of collectors rather than players. The glass in some of the Laurent flutes also contained too much zinc, which migrates out, leaving the material pitted and opaque. Fortunately, that is not the case in this instance.