In music, a bow is a device pulled across the strings of a string instrument in order to make them vibrate and emit sound.
Violin Bow Materials
A bow typically consists of a length of wood with some other material stretched between its ends. The type of bow used to play the violin and related instruments has many hairs stretched between its ends, but bows used in other cultures often stretch a single piece of string between the ends of the wood.
Fine modern bows used to play orchestral string instruments of the violin family (the violin, viola, cello and double bass) are usually made of Pernambuco wood from Brazil and are strung with horse-hair. Silver or gold, ebony wood from Africa, ivory, pearl shell, leather, and sometimes tortoise shell are materials commonly used for the "frog" and finger grip. Some fine synthetic bows are also made of fiberglass and other man made materials. Cheaper bows can also be made of synthetic materials and less suitable types of wood.
A bow maker or luthier typically uses 150 hairs for the bows for violin family instruments. Inexpensive bows often use nylon or synthetic hair. Rosin, which is sticky and made from tree sap, is regularly applied to the bow hair so that the bow moving across the instrument's strings will cause the string to vibrate and produce a tone.
The characteristic long, sustained, and singing sound produced by the violin, viola, violoncello, and double bass is due to the drawing of the bow against their strings. This sustaining of musical sound with a bow is comparable to a singer using breath to sustain sounds and sing long, smooth, or legato melodies. Without the bow the violin family could only be played pizzicato.
When the player pulls the bow across the strings, it is called a downbow; pushing in the direction of the tip is an upbow (the directions "down" and "up" are literally descriptive for violins and violas, and are employed in analogous fashion for the cello).
Generally, the downbow stroke is used for the strong musical beats, the upbow for weak beats. However, in the viola da gamba, it is the reverse; thus violinists, violists, and cellists look like they are "pulling" on the strong beats when they play, whereas gamba players looks like they are "stabbing" on the strong beats. The difference almost certainly results from the different ways in which the bow is held in these instrument families: violin/viola/cello players hold the wood part of the bow closer to the palm, whereas gamba players use the opposite orientation, with the horsehair closer. The orientation appropriate to each instrument family permits the stronger wrist muscles (flexors) to reinforce the strong beat.
Playing an instrument by touching the strings with the wood of the bow rather than the hair is known by the Italian phrase col legno. Arco in Italian is the indication to use the bow hair to create the sound. See also: Sul ponticello, Sul tasto, Col legno.
With the rise of the authentic performance movement, string players have developed a revived interest in the lighter, pre-Tourte bow, as more suitable for playing stringed instruments made in pre-19th century style.
Origin of the Bow
The question of when and where the bow was invented is of interest because the bow made possible several of the most important instruments in music today. Authorities give different answers to this question, and this article will give only the predominant opinion.
Scholars are agreed that stringed instruments as a category existed long before the bow. There was a long period—possibly thousands of years—in which all stringed instruments were plucked.
In fact, it is likely that bowed instruments are not much more than a thousand years old. Eric Halfpenny, writing in the 1988 Encyclopedia Britannica, says "bowing can be traced as far back as the Islamic civilization of the 10th century ... it seems likely that the principle of bowing originated among the horse cultures of Central Asia, whence it spread quickly through Islam and the East, so that by 1000 it had almost simultaneously reached China, Java, North Africa, the Near East and Balkans, and Europe." Halfpenny notes that in many Eurasian languages the word for “bridge” etymologically means "horse," and that the Chinese regarded their own bowed instruments as having originated with the "barbarians" of Central Asia.
The Central Asian theory is endorsed by Werner Bachmann, writing in the New Grove. Bachmann notes evidence from a tenth century Central Asian wall painting for bowed instruments in what is now the city of Kurbanshaid in Tajikistan.
Circumstantial evidence also supports the Central Asian theory. All the elements that were necessary for the invention of the bow were probably present among the Central Asian horse peoples at the same time:
- In a society of horse-mounted warriors (the horse peoples included the Huns and the Mongols), horsehair obviously would have been available.
- Central Asian horse warriors specialized in the military bow, which could easily have served the inventor as a temporary way to hold horsehair at high tension.
- To this day, horsehair for bows is taken from horses in northern climates, since such hair provides more friction. The Web site Bow-Hair.com (http://www.bow-hair.com/section2/history.htm) specifically endorses Mongolian horsehair as superior for bows.
- Rosin, crucial for creating sound even with coarse horsehair, is used by traditional archers to maintain the integrity of the string and (mixed with beeswax) to protect the finish of the bow
From all this it is tempting to imagine the invention of the bow: some Mongol warrior, having just used rosin on his equipment, idly stroked his harp or lyre with a rosin-dusted finger and produced a brief continuous sound, which caused him to have an inspiration; whereupon he seized his bow, restrung it with horsehair, and so on. Obviously, the degree to which this fantasy is true will never be known.
However the bow was invented, it soon spread very widely. The Central Asian horse peoples occupied a territory that included the famous Silk Road, along which goods and innovations were shipped rapidly for thousands of miles (including, via India, by sea to Java). This would account for the near-simultaneous appearance of the musical bow in the many locations cited by Halfpenny.
The Modern Violin Bow
The kind of bow in use today was brought into its modern form largely by the bow-maker François Tourte in 19th century France. Pernambuco wood which was imported into France to make textile dye, was found by the early French bow masters to have just the right combination of strength, resiliency, weight, and beauty. Even so, a violin or a bow maker must choose sound quality above all, when choosing wood to make bows and instruments. A common practice even today, is to reserve the best and most beautiful tone wood for bows and instruments for a makers most expensive works. In order to shape the curve or “cambre” of the bow stick, a maker must first carve and then gradually heat the stick. A metal or wooden template is used to get the exact models curve and shape while heating. The art of bow making has changed little since the 19th century. The image on the left shows a modern violin bow. Turning the screw causes the frog to move, which adjusts the tension on the hair.