HARMONICHORD, an ingenious kind of upright piano, in which the strings were set in vibration not by the blow of a ham mer but by friction. One of the many attempts to fuse piano and violin, the harmonichord was invented by Johann Gottfried and Johann Friedrich Kaufmann (father and son) in Saxony at the beginning of the 19th century. The space under the keyboard was enclosed, a knee-hole being left in which were two pedals used to set in rotation a large wooden cylinder fixed just behind the keyboard over the levers. The cylinder (in some specimens covered with chamois leather) tapered towards the treble-end. When a key was depressed, a little tongue of wood, one end of which stopped the string, was pressed against the revolving cylinder, and the vibrations produced by friction were transmitted to the string and reinforced as in piano and violin by the sound board. Carl Maria von Weber must have had some opinion of the possibilities of the harmonichord, since he composed for it a con certo with orchestral accompaniment.