The arrow may move on itself from the time it leaves the bow until it alights on the target for one of seven reasons: crookedness in the arrow; lightness or heaviness in its feathers; the height of some of its feathers and the lowness of others; lightness of the arrowhead with excessive feathering; heaviness of the arrowhead with inadequacy of the feathers; narrowness of the nock and thickness of the string, which cause the arrow to leave the string draggingly; weakness of the archer; poorness of the loose; and weakness of the bow itself.
The arrow which leaves the bow moving, or wagging, until it has reached half the range, but then becomes steady and travels the remaining distance straight until it falls, may be influenced by one of three things: thinness and crookedness of the two siyahs; excessive pressure of the index finger against the nock and the string; and too strong a bow for the archer.
The arrow which leaves the bow straight and accurately pointed until it reaches half the range, but then swerves and wags, may be influenced by one of eight things: lightness of the arrow in proportion to the strength of the bow; oversize of the nock and thinness of the string; the presence of a hole or split in the arrow into which air may enter and cause the arrow to move on itself; a loose hold upon the grip at the time of the release; crookedness in the arrow either close to the nock or close to the arrowhead; greater strength in the lower limb than in the upper; oversize of one of the two eyes of the string; and crookedness of the grip or of one of the two arms.
The arrow which gads or wags and swerves either to the right or to the left may be influenced by one of two things first, the feathers and the poorness of the draw—for the archer may draw toward the right and the feathers be on the left side, or toward the left and the feathers be on the right side—so that the arrow is shaken because of the poorness of the draw and swerves to the side on which the feathers are; or, second, the height of the upper bowtip in relation to a low position of the hand.
The arrow which moves on itself as it approaches the target may do so from one of eight things: crookedness in the arrow, either near the nock or near the head; lightness of the arrow; too large a nock; a concealed hole or split in the arrow; a loose hold upon the grip at the moment of release; a slight preponderance of the lower limb over the upper; too large eyes in the string; and an apparent crookedness in the grip.
The arrow moves on itself toward the end of its flight and not at the beginning because the disturbing factor fails to make itself evident until the greater part of the momentum has been expended. At the beginning of flight it travels straight because of the power of the bow and the strength of discharge, but when it approaches the mark those forces diminish, making it possible for the swerving factor to manifest itself. On the other hand, an arrow wags first and steadies itself last because the two siyahs are crooked and therefore discharge the arrow unevenly and cause it to wag, but, as it proceeds and the disturbing factor diminishes in power, it becomes steady and travels straight for the remaining distance.
Similarly, if the base of the index finger presses too hard against the nock, the arrow is slightly bent and will emerge disturbed and unevenly. As it reaches the middle of the range, the disturbing factor diminishes in strength and the arrow regains its straight course. Likewise, in the case of a weak archer with too strong a bow, certain factors disturb the arrow at the commencement of its flight but, as they diminish, the arrow resumes its straight course. Let the archer therefore avoid using a bow the weight of which is greater than his strength warrants.