Abstract: The inside surface of a conductive vessel (preferably spherical) with insulated adjacent segments is coated with a dielectric layer. The vessel is then partly filled with a conductive liquid-like material such as mercury having an upper surface which remains approximately horizontal irrespective of the inclination of the vessel. The capacitance between the segments and liquid varies as a function of the vessel's inclination. Vibration-induced surface action also produces varying capacitance which can be detected for seismometer applications and the like.