HARMONICA  , a generic

term applied to musical instruments in which sound is produced by friction upon glass bells . The word is also used to designate instruments of percussion of the Glockenspiel type, made of steel and struck by hammers (Ger . Stahlharmonika) . The origin of the glass-harmonica tribe is to be found in the fashionable 18th century instrument known as musical glasses (Fr. verrillon), the principle of which was known already in the 17th century.' The invention of musical glasses is generally ascribed to an Irishman, Richard Pockrich, who first played the instrument in public in Dublin in 1743 and the next year in England, but Eise12 described the verrillon and gave an illustration of it in 1738 . The verrillon or Glassspiel consisted of 18 beer glasses arranged on a board covered with cloth, water being poured in when necessary to alter the pitch . The glasses were struck on both sides gently with two long wooden sticks in the shape of a spoon, the bowl being covered with silk or cloth . Eisel states that the instrument was used for church and other solemn music . Gluck gave a concert at the " little theatre in the Haymarket " (London) in April 1746, at which he performed on musical glasses a concerto of his composition with full orchestral accompaniment . E . H . Delaval is also credited with the invention . When Benjamin Franklin visited London in 17J7, he was so much struck by the beauty of tone elicited by Delaval and Pockrich, and with the possibilities of the glasses as musical instruments, that he set to work on a mechanical application of the principle involved, the eminently successful result being the glass harmonica finished in 1762 .

In this the glass

bowls were mounted on a rotating spindle, the largest to the left, and their under-edges passed during each revolution through a water-trough . By applying the fingers to the moistened edges, sound was produced varying in intensity with the pressure, so that a certain amount of expression was at the command of a good player . It is said that the timbre was extremely enervating, and, together with the vibration caused by the friction on the finger-tips, exercised a highly deleterious effect on the nervous system . The instrument was for many years in great vogue, not only in England but on the Continent of Europe, and more especially in Saxony, where it was accorded a place in the court orchestra . Mozart, Beethoven, Naumann and Hasse composed music for it . Marianne Davies and Marianna Kirchgessner were celebrated virtuosi on it . The curious vogue of the instrument, as sudden as it was ephemeral, produced emulation in a generation unsurpassed for zeal in the invention of musical instruments . The most notable of its offspring were Carl Leopold Rollig's improved harmonica with a keyboard in 1786, Chladni's euphon in 1791 and clavicylinder in 1799, Ruffelsen's melodicon in 'Soo and 1803, Franz Leppich's panmelodicon 181o, Buschmann's uranion in the same year, &c . Of most of these nothing now remains but the name and a description in the Allgemeine musikalische Zeitung, but there are numerous. specimens of the Franklin type in the museums for musical 'instruments of Europe . One specimen by Emanuel Pohl, a Bohemian maker, is preserved in the Victoria and Albert Museum, London . For the steel harmonica see GLOCKENSPIEL . (K .

S.) ' See G . P . Harsdorfer, Math. and philos . Erquickstunden (

Nuremberg, 1677), ii . 147 . 2 Masscus abrobibairos (Erfurt, 1738), p . 70 .