NAIL VIOLIN (Ger. Nagelgeige, Nagelharmonica ), a musical curiosity invented by Johann Wilde, a musician in the imperial orchestra at St Petersburg. The nail violin or harmonica consists of a wooden soundboard about I z ft. long and 1 ft. wide bent into a semicircle. In this soundboard are fixed a number of iron or brass nails of different lengths, tuned to give a chromatic scale. Sound is produced by friction with a strong bow, strung with black horsehair. An improved instrument, now in the collection of the Hochschule in Berlin, has two half-moon sound-chests of different sizes, one on the top of the other, forming terraces. In the rounded wall of the upper sound-chest are two rows of iron staples, the upper giving the diatonic scale, and the lower the intermediate chromatic semitones. History records the name of a single virtuoso on this instrument, which has a sweet bell-like tone but limited technical possibilities; he was a Bohemian musician called Senal, who travelled all over Germany with his instrument about 1780-1790. (K. S.)