GUNNERY

or BALLISTICS, is that portion of artillery science which deals with the flight of projectiles, and the means whereby accurate shooting from a firearm can be attained. ‘Interior ballistics’ is the study of the pre ure in the bore of a gun caused by the gases of the explosive which give initial velocity to the projectile, ‘Exterior ballistics’ is the theory of the flight of a mi ile traveling at high velocity, and acted on by the force of gravity and the resistance of the air. For comparatively slow motions, the retardation caused by the air varies with the square of the velocity; but with the ogival rotating projectile of a modern gun, sO many Other considerations come into play that the conditions of flight are mainly determined by experiment. A mi ile is now fired through equidistant electric screens, and the time of flight between their severed wires noted by a chronograph. By for mule used in conjunction with experimental ballistic tables, the trajectory or path of any shot at a ee velocity can be demonstrated. When once the ranges (corrected for wind, temp,, muzzle velocity,. etc.) are found, the sights of the gun or the rifle are adjusted for each distance, and their manipulation becomes a matter of mere drill.