If you do not want it to stretch in the damp winter nor shrink in the dry summer, make an eye in either end, string it on a strong bow, and, while thus braced, soak it in water until it becomes soft. Then draw the bow several times until the string stretches out to its limit, at which time you unstring the bow, twist the string once, and brace the bow again—leaving it so until the string is dry. You then remove the string and fit it on another bow that is a little stronger, and soak it again in water until it stretches out fully; at which time you unstring the bow, give the string another twist, and brace it again on the same bow until it dries. The operation is repeated until the string ceases to stretch any more. It is then rubbed down carefully with a fine polishing stone, after which it should be given—in the summer—a coat of a thick solution of gum Arabic to protect it against shrinking because of the dry heat. Such protection will keep it strong as well as give it greater force for driving the arrow. In winter it should be rubbed with a fine polishing stone; then treated with a mixture of fox fat and yellow beeswax melted together, making sure that the string is warm before the mixture is applied. The way to warm the string is to rub it between two very smooth stones. The mixture is thus thoroughly absorbed into the texture of the string which it renders waterproof and fit for using in the rain without damage.
There are three ways of making the eyes of a string. The first is the so-called Turkish, which is good for coarse strings to be used with weak bows because of the ease with which it is undone. The second is the Khurasanian, which is the best and finest of all knots. The third is known as the Ṣa‘dīyah, and is likewise good.
When using a string, have the thicker part up and the thinner part down. Some reverse this process and place the thinner part up and the thicker part down; but the first method is the better one since the strength of the bow lies in the upper limb, and upon it mainly depends the driving force of the bow. Therefore, the thicker part of the string should be on the side of the upper limb.
If the string be made of two pieces, have the point where the two pieces are joined together lie within the lower limb. If it be made with two connections, that is, of three pieces, have the shortest piece down and the longest piece up. If, when shooting with such a string, the arrow should wobble and wag in its flight, reverse the string, placing the shortest piece up. The arrow will then go straight because the knots are no longer opposite to each other [that is, in relation to their positions on the limbs].
When you make the eyes of the string, be sure that you use the same kind of knot in both, whether Turkish, Khurasanian, or Ṣa‘dīyah. Never mix them up, having a Khurasanian on one end and a Turkish or Ṣa‘dīyah on the other, lest you corrupt the quality of your shooting. Should the string stretch, for some reason, give it a twist or two and tie a knot in it just beside the eye (but never below it).
The eyes of the string are usually small in size. They should never be made large lest that militate against the shooting, increase its faults, and weaken the driving force of the bow-besides, oftentimes causing the string to slip off the nocks. The author of The Book on the Different Kinds of Weapons (Kitāb Ajnās al-Silāḥ) said that the eyes which incline toward being wide and long give greater driving force for the arrow, longer range, and harder hitting, although, he added, the arrow is apt to wobble in its flight and the string hit the forearm of the archer. Therefore, he who desires great driving force and long range should make the eyes of the string long and wide, ignoring the wobbling of the arrow, since he is after distance not accuracy. The present author is of the opinion that this statement is not plausible since the wobbling of an arrow in flight dissipates its force and reduces its range. Likewise, one eye should not be wide and the other narrow except so far as is necessitated by thickness of the upper part of the string and thinness of the lower.