Katers Pendulum

Kater's Pendulum was invented by Henry Kater, and used by him about 1817 to determine the length of the seconds pendulum. It consists of a long metallic bar provided with knife-edges at two points - one near each end. Between the knife edges are two movable weights, which can be so arranged that whichever way up the pendulum is suspended, the time of oscillation is the same. The distance between the two edges, which are thus made to become in turn centres of suspension, can be proved to be equal to the length of the equivalent simple pendulum. From this the length of the seconds pendulum can be calculated, for the time of oscillation of a single pendulum is proportional to the square root of its length. [Pendulum.]