Abstract: Enhanced compound pendulums provide thermal compensation and/or barometric compensation, such as for a mechanical clock system. The enhanced compound pendulums are simple to construct, and can be more easily compensated than conventional, single-bob pendulums. The enhanced compound pendulums typically comprise material that is added above the point of rotation. Thermal expansion factors for components of the enhanced compound pendulums may preferably be chosen to provide thermal compensation to the first order. In some embodiments of enhanced compound pendulums, volume is added above the pivot to provide barometric compensation, such as by equalizing the moments above and below the pivot, or by providing geometric symmetry above and below the pivot, with a lower density above the pivot.

Abstract: A method and apparatus for accurately controlling a timekeeping apparatus utilizing a relatively heavy free pendulum or other harmonic structure carrying a permanent magnet, and a powered harmonic structure carrying a ferromagnetic element. The magnet is positioned on its carrier in a manner to effect energy transfer between the pendulums or structures during intermittent periods of magnetic attraction as the two structures oscillate. The free structure governs the speed of oscillation of the powered structure to maintain accurate control over the latter and energy transferred from the powered structure to the free structure maintains continued oscillation of the governing, free structure.