[L. pendulus.] An instrument consisting of a weight suspended from a fixed point, and free to swing to and fro by the alternate force of momentum and gravity. It is used to regulate the movements of clock-work and other machinery. The principal kinds in common use are - the simple, the compound, the mercury, and the gridiron pendulums.

SIMPLE PENDULUM

PENDULUM Lumilux

MERCURY

GRIDIRON