The mirror apparatus from a lightvessel under repair at one of the Trinity House onshore depots. The light and mirror assembly are mounted 43 feet above sea level. Four groups of electric lamps, each with their mirror reflectors carefully aligned, provide the appropriate 'flash' effect to the mariner. The whole assembly is mounted upon ball bearings for ease of rotation by electric motor. At the base is a 'pendulum' which ensures that the light is maintained in the correct orientation regardless of the extent of the swell. 'Gimbals,' or pivots, are mounted in each horizontal plane to permit the light assembly to adjust thus ensuring the that it remains upright at all times and that the light is correctly in focus. [273] [280]