Shepherd Gate Clock

The Shepherd Gate Clock (51°28′41″N 0°00′05″W) is mounted on the wall outside the gate of the Royal Observatory, Greenwich building in Greenwich, Greater London. The clock, an early example of an electrically connected clock system, was a sympathetic clock mechanism controlled by electric pulses transmitted by a motor clock inside the main building. The network of 'sympathetic clocks' was constructed and installed by Charles Shepherd in 1852. The clock by the gate was probably the first to display Greenwich Mean Time to the public, and is unusual in using the 24-hour analog dial. Also, it originally showed astronomical time which started at noon, not midnight. The gate clock distributed the time publicly; another time signal of the observatory was the time ball, since 1833. The time ball only signalled 1 pm (13:00), but could be seen from afar. Eventually the idea of distributing time signals via wires led to more and more electrical distribution of time signals by this method. Time signals, besides from their general importance in the affairs of business, were especially important for running ships and trains punctually. The situation was exacerbated by a lack of accuracy in many clocks compared to modern time-keepers.