主题：【原创】苏格兰之行第一天，Edinburgh -- flyingfox

The One O'Clock Gun is a time signal, and is fired every day, except Sunday, at precisely 13:00. The gun was established in 1861, as a time signal for ships in the Firth of Forth, and complemented the time ball, which was installed on Nelson's Monument in 1852, but which was useless during foggy weather. The gun could easily be heard by ships in Leith Harbour, 2 miles (3.2 km) away. Because sound travels relatively slowly (approximately 343 metres per second (770 mph)), maps were produced in the 1860s to show the actual time when the sound of the gun was heard at various locations in Edinburgh.

The original gun was an 18-pound muzzle loading cannon, which needed four men to load, and was fired from the Half Moon Battery. This was replaced in 1913 by a 32-pound breech loader, and in May 1952 by a 25-pound Howitzer. The present One O'Clock Gun is a L118 Light Gun, brought into service on 30 November 2001.

The Gun is now fired from Mill's Mount Battery, on the north face of the Castle, by the District Gunner from 105th Regiment Royal Artillery (Volunteers). Although the gun is no longer required for its original purpose, the ceremony has become a popular tourist attraction, and is also fired to mark the arrival of the New Year as part of Edinburgh's Hogmanay celebrations. The longest-serving District Gunner, Staff Sergeant Thomas McKay MBE, nicknamed "Tam the Gun", fired the One O'Clock Gun from 1979 until his death in 2005. McKay established the One O'Clock Gun Association, which opened a small exhibition at Mill's Mount.