One O'Clock Gun

In 1853, a time ball was installed atop the Nelson Monument on Calton Hill in Edinburgh. This device, on which a ball dropped at a given time, allowed ships in port to accurately set their chronometers prior to sailing. While the time ball could be seen from Leith Harbor on clear days, it was obscured from view if fog or foul weather was present. To counter this issue, a gun at the castle was fired each day at 1:00 PM to coincide with the dropping of the ball. The type of gun used has changed over time from an 18-pdr cannon in 1853, to a L118 Light Gun today. Placed on the Mill's Mount Battery, the One O'clock Gun is still fired daily with the exception of Sundays and holidays.