Democratic Sentinel, Volume 12, Number 50, Rensselaer, Jasper County, 4 January 1889 — Deviation of the Pendulum. [ARTICLE]

Deviation of the Pendulum.

A simple method of rendering visible the deviation of the Foucault pendulum has recently been devised by Mr. Campbell. The bob of the pendulum is replaced by a permanent magnet of a cylindrical form, placed with its axis coinciding in direction with the suspended wire. On a point vertically beneath the center of suspension is swung horizontally a light bar of some magnetic material, carrying a mirror from which is reflected a beam of light. On putting the pendulum in vibraton in the vertical plane which contains the bar, the latter follows the deviation of the pendulum, which is thus rendered very visible by the corresponding reflection of the luminous beam.