Eccentric Projectiles

A spherical projectile in which the centre of inertia does not coincide with the centre of figure. Such projectiles are subject to great deviations, which can be predicted as to direction by knowing the position of the centre of inertia of the shot in the bore of the gun. (See Projectiles, Deviation of .) The side of the ball upon which the centre of inertia lies can be found by floating it in a bath of mercury, and marking the highest point where it comes to a state of rest; the centre of inertia lies nearest the opposite side; its exact position is determined by a kind of balance called the eccentrometer ; the ball is placed in the balance with the marked point nearest the fulcrum; the distance of the centre of inertia or gravity from the fulcrum is obtained by dividing the product of the counterbalancing weight and its distance from the fulcrum by the weight of the projectile.