7. The altitude of the curve is the perpendicular height of the principal vertex above the horizon.
8. The amplitude, random, or range, is the distance between the point of projection and the object aimed at.
9. The elevation of the piece is the angle its axis (produced) makes with the horizon, and the axis itself is called the direction.
10. The horizontal distance to which a mortar, elevated to a given angle, and loaded with a given quantity of powder, throws a shell of a given weight, is called the range of that mortar, with that charge and elevation.
11. The inclination of a plane is the angle it makes with the horizon either above or below.
12. The directrix is the line of motion, along which the describing line or surface is carried in the genesis of any plane or solid figure.
Laws of motion in Gunnery.
1. Spaces equally run through with equal velocities, are to one another as the times in which they are run through, and conversely.
2. Spaces equally run through in the same or equal times, are to one another as the velocities with which they are run through, and conversely.
3. Spaces run through are in the same proportion to one another, as their times multiplied into their velocities, and conversely.