STRINGED MUSICAL INSTRUMENTS may be di vided into five different classes, according to the method whereby the strings are set in vibration.
1. Strings Plucked by Fingers or Plectrum.—Twanging the strings by the fingers is the most primitive method, probably suggested by the feeble note given out by the tense string of the hunter's bow. The nanga of the ancient Egyptians, of which specimens are preserved in the British Museum, is the only link as yet discovered between the bow and the harp.
The next step observed is the device of stretching the strings partly over a soundboard and partly a vide, as in the cithara, the lyre, the rotta, the crwth, etc. In this stage the strings were made to bridge an open space for greater convenience in twang ing them with both hands. The gradual closing up of this open space marked the steps in the transition from cithara to fiddle.
When the principle of stopping strings by pressing them against a fingerboard in order to obtain several sounds from each had been discovered and applied by adding a neck to the body, a new subdivision was created in this class of instruments. This prin ciple involved a very great advance in technique, and produced the two great families of guitar and lute. The addition of a key board to the psaltery, created another new class of instruments, of which the principal members were the clavicymbalum, the virginal, spinet and the harpsichord.
2. Strings Struck by Hammers or Tangents.—The earliest known instrument thus played was the Assyrian dulcimer, or pisantir. In this, as in the psaltery, the strings were stretched over a rectangular or trapezoid sound-chest and were struck by sticks or hammers. The dulcimer has survived in the cembalo or cimbalom of the Hungarian gipsies. The addition of a keyboard produced the clavichord, and later the pianoforte.
3. Strings Set in Vibration by Friction of a Bow.—Al though used with various other instruments, such as the Oriental rebab and its European successor the rebec, with the oval vielle, the guitar or troubadour-fiddle and the viols, it is with the effect of the bow on the perfected type represented by the violin family that we are mostly concerned. The strings in this case are all of
the same length, difference in pitch being secured by thickness and tension. The fingers, by pressing the strings, produce a variety of notes from each string at will by shortening the vi brating section as the position of the fingers shift in the direction of the bridge. To this class belong also the Welsh crwth and the tromba marina.
4. Strings Set in Vibration by Friction of a Wheel.—This class is small, being represented mainly by the organistrum, and the hurdy-gurdy and a few sostenente keyboard instruments. In these instruments the rosined wheel performs mechanically the function of the bow, setting the strings in vibration as it revolves. A row of ten or 12 keys controlling wooden tangents performs the function of the fingers in stopping the strings.
5. Strings Set in Vibration by the Wind.—An example is the aeolian harp. Here the eight strings of different thickness, but tuned strictly in unison and left slack, are set in vibration by a current of air passing obliquely across them causing the strings to divide into aliquot parts, thus producing various harmonics.
In regard to the structural features of stringed instruments the construction of the sound-chest divides those played by hand into two distinct classes, viz., those with the box-form type, con sisting of back and belly (or sound board), joined by ribs of equal width, and those with a vaulted back to which is attached directly a flat sound board, without the intervention of ribs.