7. It will be readily seen that a defective position of the line of sight will cause an inaccuracy of fire, and this may be occasioned by a false position be ing given to either the front or rear sight. If the front sight be to the right of its proper place, the bullet will go to the left and vice versa. The bullet , will also be raised (range increased), since the top of the sight is lower than it is when in its proper position. If the rear sight be to the right or left of its true place, the bullet will go to the right or left, and will be lowered (range diminished), since the top of the sight will be lower than when in its true posi . tion.
8. A very frequent cause of inaccuracy of fire is the incorrect graduation t of the rear sight. Of course, if the elevations corresponding to certain ranges are not accurately marked, the fire will be wild. In determining the graduation for any particular rifle, avoid all proportions and make a series ot experiments with the greatest care. With a properly made arm and cartridge, and the elevating sight accurately graduated, any one can, by care and prac tice, become a good marksman.
9. A serious cause of inaccuracy, originating with the firer, is the faulty position that he gives to the musket in firing, by inclining to the right or left, which tends to carry the bullet to the side to which the rifle is inclined, and to diminish the range. When firing at long ranges a trifling inclination to the right or left will throw the bullet very wide of the target.
to. To prevent inaccuracies while aiming, in addition to keeping the sight vertical, the firer should observe the following: The eye should glance from the sights to the target, being constantly on the target. If the particular rifle carries higher or lower than the average, it must be remedied by aiming with a fine or a coarse sight. In aiming raise the rifle. Upward motion acts against gravity, and has a tendency to prevent any lateral motion of the muz zle. Hold the butt firmly against the shoulder, and do not turn the head away at the instant of pulling the trigger. Fire low rather than too high.
After firing a few shots on a dry, hot day, the bullets gradually fall lower and lower, in consequence of the fouling of the barrel. The barrel should be kept clean and, as far as possible, not overLheated.
12. The condition of the atmosphere noticeably affects the course of the bullet. The more moisture there is in the air, the less elevation required. The bullet is frequently noticed to fall immediately after a rain. Warm air .)ffers less resistance to the bullet than does cold air. A fall of 20 degrees in tem perature will cause the bullet to lower ten to eleven inches at 30o yards range. '
In tiring over water the elevation must be increased, in consequence of the ; lower temperature of the air over the water. In ascending the inountain the . air becomes more and more rare, and consequently the resistance to the bullet is less on the mountain than at its base. Mirage, an optical illusion occurring in level districts on very wartn days, causes the target to apparently rise in the air and become distorted in shape. This materially affects such objects as are near the ground, and engenders a tendency to shoot too high.
13. The influence of light and shade on the firing is very remarkable. On , a brighl day the target is refracted so as to apparently stand hig,her, which 4 ould theoretically require a lower elevation than on a very dull clay. When the light shines directly on the target, when the target is against a light back ground (so that the details arc better broug,dit out), when the sun shines on L the firer's back, when the atinospliere is clear, wlien the ground is level and 1, uniform in appearance or when it gradually rises toward the target, the same will appear much nearer, and will theoretically require a higher elevation. The best shooting is invariably done on cloudy days when the sun's light is evenly diffused. It is very difficult to shoot well when passing clouds inter cept portions of the sun's light and heat. It is readily seen how this listurb ance might set up currcnts in the air which would tend to carry the bull.-t from its course, and how the rays of light deflected from their course before reaching the eye would cause the target to apparently occupy a false position. It will be well to diminish the elevation should the sun suddenly appear zmd light up the target while the firer still remains in the shade, and to :nerease it should the target remain in the shade while the sun shines on the firer.
14. Bright sights and barrels are obviously objectionable. The reflection of the sun's light on the sights causes them to appear as brilliant points and precludes the possibility of an accurate aim. If the sun's rays come laterally, the trouble will be yet greater, inasmuch as they will brighten the rear side of the front sight and the opposite side of the rear sight notch, and cause a tendency to shoot away from the sun. The refraction of the sun's rays from the polished barrel causes the target to become indistinct and to assume the appearance of motion. The sights and barrel about the muzzle should be blackened with smoke if nothing better is at hand.