Where the ground falls at a greater angle than the angle of fall of the projectiles (about 5 degrees at 1500 m., and 1 degree at 800 m.) a defiladed space is formed, which makes it possible to bring supports nearer to the firing line than would be practicable on level ground. If we assume that each graduation of the rear sight over 600 m. commands a space 100 m. deep with the normal core of hits, we obtain the following depths of the beaten zones at a range of 1500 m., with rifle model ’98 (angle of fall 5 degrees and 22 minutes): Ground rising 1 in 10 = 6° = 50 m. „ „ 1 in 20 = 3° = 64 m. „ „ 1 in 50 = 1° = 81 m. Ground falling 1 in 10 = 6° = 360 m. „ „ 1 in 20 = 3° = 180 m. „ „ 1 in 50 = 1° = 113 m. [Illustration] [Illustration] The figures on pages 181 and 182 show to what extent the ground is capable of increasing or diminishing the efficacy of fire. The French assert that the Würtembergers deliberately applied these principles in the defense of the park wall at =Villiers=. It was, at any rate, only an accident that the masses of troops on the west side of the gently sloping Mamelon de Villiers suffered heavy losses on November 30th, 1870. General PAQUIÉ of the French Army[171] lays down the following rule: “When the angle of slope of falling ground corresponds to the angle of fall of the lowest trajectory of a cone of dispersion, the depth of the beaten zone will be 2¹⁄₄ times greater than on level ground. When the angle of slope of falling ground is equal to the angle of fall of the mean trajectory of a cone of dispersion, the depth of the beaten zone will be 2¹⁄₂ times greater than on level ground. When the lowest trajectory of a cone of dispersion passes over the crest of a hill at the height of a man, and when the reverse slope of that hill is equal to ¹⁄₁₀₀ of the range, the depth of the beaten zone will be five times as great as on level ground.” [171] See also _Le tir de guerre et les expériences pratiques du camp de Châlons_. _Journal des sciences militaires_, Sept., Oct., Nov., 1808--_Le Joindre Général. Petit Guide pour les tirs collectifs_, 1904. These data are of no practical value in war. They serve only to increase the appreciation of fire effect when examining the terrain, and train the eye in judging such situations. The character of the ground may exert great influence when firing on intrenchments. Fire delivered from low ground against an enemy in shelter-trenches is absolutely ineffective--as shown in the action against the French IInd Corps at =Point du Jour= and by the experiences of the Russians at =Plevna= and =Gorni Dubniac=. This condition becomes aggravated the smaller the angles of fall of the projectiles, and the higher the target is situated relative to the firing position of the attacking party.