the sound of the guns travelled much faster than a dispatch rider on a horse. The guns were therefore originally used to announce the arrival of a ship, perhaps requiring provisions for the next leg of its journey, to residents living in the interior. As more modern means of communications and transportation became available, Cape Town discontinued the use of the guns to announce that a ship was in port. The original guns – 18-pounder, smoothbore muzzle-loaders – are still in use today. The ritual represents one of Cape Town's oldest living traditions. These are the oldest guns in daily use in the world. They fire every day at 12 noon sharp, except Sundays and public holidays, and are maintained by the South African Navy. Time signalling In addition to the aforementioned port hailing duties, the guns have had the task of firing a time signal since 1806. According to local tradition, the initial purpose of the gun was to allow ships in port to check the accuracy of their marine chronometers (a precision instrument used aboard ships to help calculate longitude). The gun report might be too inaccurate for ships several kilometers away if they did not correctly compensate for the relatively slow speed of sound. For this reason, ships marked their time by the puff of smoke rather than the sound, and this is one reason the guns are sited high above Cape Town Harbour. The invention of the more accurate time ball in 1818 soon made time guns redundant for mariners wishing to set their chronometers. The time ball on Signal Hill was used to relay time from the Cape Town Observatory, whose time ball was not visible from all parts of the bay. At precisely 1:30pm Cape Mean Time, the ball would be dropped at the Observatory – an observer on Signal Hill would then drop that more prominent ball too. When setting their chronometers, mariners adjusted their observation of the time ball on Signal Hill by a second to allow for the relay from the observatory. After the advent of the galvanic telegraph, it became possible to electrically trigger a gun remotely, and since 1864 the Noon Gun has been fired directly from the master clock of the oldest timekeeper in the country, the South African Astronomical Observatory. A South African Navy duty officer is present to ensure both guns are charged, explain the Noon