Line of Fire.—The prolongation of the axis of the piece.
Plane of Fire.—The vertical plane containing the line of fire.
Line of Sight.—The straight line passing through the sights and the point aimed at. (Figs. 102 and 103.)
Plane of Sight.—The vertical plane containing the line of sight.
Angle of Sight.—The angle made by the line of sight with the horizontal. (s in [Fig. 102].)
Line of Departure.—The line in which the projectile is moving when it leaves the gun.
Fig. 102.
Fig. 103.