Page:Tactics (Balck 1915).djvu/169

 Beyond 600 m., an error in the range exerts a greater influence upon the efficacy of fire than does the marksmanship of the skirmishers. When an improper elevation has been selected, the efficacy of the fire decreases as the compactness of the "cone of dispersion" increases; in other words, the efficacy of the fire decreases as the excellence of the marksmanship of the men and their coolness in the face of the enemy increase. (See pp. 170 and 171, infra).

The following expedients for ascertaining ranges may be mentioned:

(a) Pacing and galloping;

(b) Estimating distances on the ground by eye (by comparison with known distances; by estimating part of the distance);

(c) Firing trial volleys (ranging);

(d) Taking the range from a map of large scale or obtaining it directly from infantry or artillery already engaged;

(e) Measuring the range directly on the ground.

Pacing (employed in Russia, France, and Austria) gives inaccurate results. There is a difference between the number of paces a man takes per 100 m., on a chaussee and in a ploughed field. Length of pace depends upon the character and slope of the ground. In pacing over varied ground, a man follows the slope line while the projectile follows an airline. Therefore it would seem that pacing is only practicable at short ranges when the enemy is not near. The same is true of galloping over the distance. (The length of a horse's jump at a gallop is on an average 3 m.).

In estimates made by individual men, the error amounts