The anatomy of a bow: The length usually is measured from the two opposite points of attachment of the string or between nocks. The nocks are the depressions or notches which serve to hold the string from slipping. The space occupied by the hand in holding the bow is termed the handgrip or handle. The regions between the handgrip and the nocks are termed the limbs. The back of the bow is its convex side when strung. The concave side is called the belly. A bow which, when unstrung, reverses its curve, is called reflexed, while one which maintains a certain amount of curvature is said to follow the string. Setting the string tight on a bow is termed "bracing it."
The capacity of a bow to throw an arrow a given distance may be taken as a criterion of its value as a weapon, wherewith to do damage, either in the chase or in conflict. The weight and velocity of the missile are its chief characteristics, whether it be a stone, a bullet, or an arrow.
Besides the cast of a bow, there are other factors that bear directly upon its function, namely: material, size, strength, quality of recoil or action.
The material used in the construction of a bow is dictated, as a rule, by circumstances and environment. A great deal depends upon whether a bow is made of a simple wooden stave, a combination of wood and bone, or of wood, horn, sinew, and glue. All of these react differently to heat and moisture: an elaborate composite bow would quickly lose its utility in a damp climate; a simple wooden stave also becomes flaccid in extremely hot weather.
Size.—On horseback, or hunting in brushy country, a short bow is more convenient to use: Indian, Persian, and Turkish bows bear witness to this fact. The ancient English archer could use a longbow because he was a foot soldier.
The strength of a bow is determined by the strength of the man and the purpose of the weapon. Most American Indian bows now extant seem constructed entirely for hunting small game, and consequently do not demand great power. But in days gone by, the object of every archer was in time of war to deal as powerful a blow, at as great a distance, as possible.
Men of different nations do not differ greatly in strength. A bow may pull or "weigh" a great deal yet not have corresponding resiliency and lack a cast proportionate to its resistance. This would then be called a bow of dull cast, and one of active recoil and quick response would be called quick or lively, or brilliant in cast.
Because of lack of proper balance or distribution of action in the arc of a bow, it may recoil so unevenly as to jar the hand, or kick in the grasp, or be unpleasant to use. This sort of bow militates against accurate shooting and would be called a "harsh bow," while a bow well balanced and pleasant to shoot has been called soft, or a "sweet bow."
The amount of force necessary to draw a bow is called the weight of a bow. Apparently the Chinese were the first people to classify bows according to weight standards. The first reference to weights in England seems to date from the renaissance of archery, about 1798. The method of estimating the strength of a bow was either to suspend weights to the string until the arrow length was drawn, or to use a steelyard attached to the string while full drawn. By fixing the bow in a vise, hooking a spring scale to the string, and drawing it 28 inches away from the back of the bow, we get from the scale the amount of pull necessary to draw a standard English arrow to the head.