APPARATUS WITH ADJUSTABLE PERIOD FOR MEASURING SMALL DEVIATIONS FROM A TRUE HORIZONTAL PLANE

摘要

An apparatus adapted continuously to measure and record small deviations from a true horizontal plane such as those deviations which may occur continuously or recurrently as a result of ground motion and the like. The apparatus comprises a diamagnetic body suspended in a magnetic field of a configuration which constrains the body radially but permits it to move axially within certain limits. The amount of axial movement is used as a measure of horizontal deviation. The suspension is frictionless, and the apparatus may be made to be relatively rugged and stable over extended periods of time. Adjustable magnetic force restoring means are provided to change and control the natural period of the instrument to optimize it performance over a wide range of applied force.