RANGE-FINDING.
The range is found by sound, by observation, by taking measurements from the map, by means of range-finders, and by trial shots.
By Sound.—Multiply the number of seconds between burst of projectile and report of same by 370 to obtain the approximate range in yards.
By Observation.—As indicated in the rules given above regarding the appearance of objects.
By Taking Measurements from the Maps.—This can be done on a good topographical map on a large scale, taking care to fix thereon accurately the position of the target and also the position of the gun.
By Means of Range-finders.—No range-finder has been adopted for our service; but several instruments are now under consideration.
Whatever range-finder may be used, and with whatever care the range may be taken, errors will exist; but they may be reduced to a minimum by a good instrument and skilled observers.
Trial Shots.—If the range be doubtful or unknown, trial shots will be used, but it must be remembered that trial shots disclose your position.
Estimate the range, give the elevation indicated for it by the range table, and the necessary drift (or deflection), each unit of the deflection scale on the sight corresponding to 1/345[8] of the range, and proceed as indicated under Target Practice, page 379.
Sighting.—The nearer the eye is to the rear sight the better will the front sight be seen, and the finer can the sight be taken. The same distance should be taken for each shot, if possible. In setting the sight it is well to bear in mind that the deviation of the projectile follows the motion of the rear-sight point: thus, if it be moved up further than is required, the projectile will strike high; if it be moved too far to the right, the projectile will go too far to the right of the object aimed at. Also in allowing for the wind move the sight into the wind, i.e, in the direction the wind comes from.