Let A B B', in the accompanying figure, represent a horizontal plane pierced by trajectories C B and C' B', at an angle a, forming the beaten zone B B'. If now the ground falls from B in the direction B D, it is obvious from the figure, that the angle of fall decreases and the beaten zone B D increases. The limit of this increase is reached when the angle of slope is greater than the angle of fall of the projectile. In this case there is a dead angle beyond B and toward D. If, on the other hand, the ground be rising, the angle of fall will be C' D' B and the beaten zone[1] decreases to B D'. The smaller the angle of fall of the projectile the greater the influence of the ground.
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From this it follows that when fire direction is in competent
hands the appearance of the enemy on the terrain as at
B D will be fully taken advantage of, while firing on slope
like B D' should be avoided. Troops will, however, rarely
be in a position from which they can see a target on the slope
B D. The efficacy of the fire will in such a case be more or less= angle of slope (rising or falling);
b = beaten zone on level ground;
then a/(a - [Greek: g])b))b] = beaten zone on falling ground;
a/(a + [Greek: g])b + [Greek: g]))[Greek: b]] = beaten zone on rising ground.
</poem> ]
- ↑ The computation of beaten zones is based upon the formula deduced by Lieutenant-General Rohne in his work Schieszlehre für Infanterie, p. 127: <poem> Let a = angle of fall; [Greek: g
