(T. As.)
[1] It is not likely that any remains of it now exist.
BOW (pronounced “bō”), a common Teutonic word for anything bent[1] (O. Eng. boƺa; cf. O. Sax. and O.H.G. bogo, M.H.G. boge, Mod. Ger. bogen; from O. Teut. stem bug- of beugan, Mod. Ger. biegen, to bend). Thus it is found in English compound words, e.g. “elbow,” “rainbow,” “bow-net,” “bow-window,” “bow-knot,” “saddle-bow,” and by itself as the designation of a great variety of objects. The Old English use of “bow,” or stone-bow, for “arch,” now obsolete, survives in certain names of churches and places, e.g. Bow church (St Mary-in-Arcubus) in Cheapside, and Stratford-le-Bow (the “Stratford-atte-Bowe” of Chaucer). “Bow,” however, is still the designation of objects so various as an appliance for shooting arrows (see [Archery]), a necktie in the form of a bow-knot (i.e. a double-looped knot), a ring or hoop forming a handle (e.g. the bow of a watch), certain instruments or tools consisting of a bent piece of wood with the ends drawn together by a string, used for drilling, turning, &c., in various crafts, and the stick strung with horsehair by means of which the strings of instruments of the violin family are set in vibration. It is with this last that the present article is solely concerned.
Bow in Music.—The modern bow (Fr. archet; Ger. Bogen; Ital. arco) consists of five parts, i.e. the “stick,” the screw or “ferrule,” the “nut,” the “hair” and the “head.” The stick, in high-grade bows, is made of Pernambuco wood (Caesalpinia brasiliensis), which alone combines the requisite lightness, elasticity and power of resistance; for the cheaper bows American oak is used, and for the double-bass bow beech. A billet rich in colouring matter and straight in the grain is selected, and the stick is usually cut from a templet so as to obtain the accurate taper, which begins about 4¼ in. from the nut, decreasing according to regular proportions from 3⁄8 in. at the screw to 3⁄16 at the back of the head. The stick is cut absolutely straight and parallel along its whole length with the fibre of the wood; it is then bent by heat until it is slightly convex to the hair and has assumed the elegant cambrure first given to it by François Tourte (1747-1835). This process requires the greatest care, for if the fibres be not heated right through, they offer a continual resistance to the curve, and return after a time to the rigid straight line, a defect often observed in cheap bows. The sticks are now of either cylindrical or octagonal section, and are lapped or covered with gold thread or leather for some inches beyond the nut in order to afford a firm grip. The length of the stick was definitely and finally fixed by François Tourte at 29.34 to 29.528 in.
The centre of gravity in a well-balanced violin bow should be at 19 cm. (7½ to 7¾ in.) from the nut;[2] in the violoncello bow the hair measures from 60 to 62 cm. (24 to 25 in.), and the centre of gravity is at from 175 to 180 mm. (7 to 7¼ in.) from the nut. In consequence of the flexure given to the stick, Tourte found it necessary to readjust the proportions and relative height of head and nut, in order to keep the hair at a satisfactory distance from the stick, and at the necessary angle in attacking the strings so as to avoid contact between stick and strings in bowing. In order to counterbalance the consequent increased weight of the head and to keep the centre of gravity nearer the hand, Tourte loaded the nut with metal inlays or ornamental designs.
The screw or ferrule, at the cylindrical end of the stick held by the hand, provides the means of tightening or loosening the tension of the hair. This screw, about 3¼ in. long, hidden within the stick, runs through the eye of another little screw at right angles to it, which is firmly embedded in the nut.
The nut is a wooden block at the screw end of the stick, the original purpose of which was to keep the hair at a proper distance from the stick and to provide a secure attachment for the hair. The whole nut slides up and down the stick in a groove in answer to the screw, thus tightening or relaxing the tension of the hair. In the nut is a little cavity or chamber, into which the knotted end of the hair is firmly fixed by means of a little wedge, the hair being then brought out and flattened over the front of the nut like a ribbon by the pressure of a flat ferrule. The mother-of-pearl slide which runs along a mortised groove further protects the hair on the outside of the nut. Bows having these attachments of ferrule and slide, added by Tourte at the instigation of the violinist Giovanni Battista Viotti, were known as archets à recouvrements.
The hair is chosen from the best white horsehair, and each of the 150 to 200 hairs which compose the half-inch wide ribbon of the bow must be perfectly cylindrical and smooth. It is bought by the pound, and must be very carefully sorted, for not more than one hair in ten is perfectly cylindrical and fit for use on a high-grade bow. Experience determines the right number of hairs, for if the ribbon be too thick it hinders the vibration of the strings; if too thin the friction is not strong enough to produce a good tone. Fétis gives 175 to 250 as the number used in the modern bow,[3] and Julius Rühlmann 110 to 120.[4] Tourte attached the greatest importance to the hairing of the bow, and bestowed quite as much attention upon it as upon the stick. He subjected the hair to the following process of cleansing: first it was thoroughly scoured with soap and water to remove all grease, then steeped in bran-water, freed from all heterogeneous matter still adhering to it, and finally rinsed in pure water slightly blued. When passed between the fingers in the direction from root to tip, the hair glides smoothly and offers no resistance, but passed in the opposite direction it feels rough, suggesting a regular succession of minute projections. The outer epithelium or sheath of the hair is composed of minute scales which produce a succession of infinitesimal shocks when the hair is drawn across the strings; the force and uniformity of these shocks, which produce series of vibrations of equal persistency, is considerably heightened by the application of rosin to the hair. The particles of rosin cling to the scales of the epithelium, thus accentuating the projections and the energy of the attack or “bite” upon the strings. With use, the scales of the epithelium wear off, and then no matter how much rosin is applied, the bow fails to elicit musical sounds— it is then “played out” and must be re-haired. The organic construction of horsehair makes it necessary, in hairing the bow, to lay the hairs in opposite directions, so that the up and down strokes may be equal and a pure and even tone obtained. Waxed silk is wound round both ends of the hair to form a strong knot, which is afterwards covered with melted rosin and hardens with the hair into a solid mass.