Everyone knows about the One O�Clock Gun but fewer have heard of the One O�Clock Ball. It is hoped greater interest in the other historic chronological marker in Edinburgh, the time ball, will emerge as the 156-year-old item is restored.

Everyone knows about the One O'Clock Gun but fewer have heard of the One O'Clock Ball.

It is hoped greater interest in the other historic chronological marker in Edinburgh, the time ball, will emerge as the 156-year-old item is restored. A project to revamp the time ball on top of the Nelson Monument on Calton Hill received a boost with a Heritage Lottery Fund grant of £50,000.

The time ball's purpose was to enable ships' captains in Leith docks to set their chronometers accurately by observing the dropping of the ball at one o'clock GMT each day. Nine years later the one o'clock gun at Edinburgh Castle was added, to give an audible signal.

The gearing mechanism for the time ball is in need of repair and has not operated for more than 18 months.

Some of the cogs are worn and parts of the supporting timber structure need to be replaced. The Nelson Monument itself will also see work, with some stonework repair and replacement, and extensive re-pointing in lime mortar.

Adam Wilkinson, director of Edinburgh World Heritage said: "This important project is part of the wider restoration of the monuments and statues in the World Heritage Site.

"The time ball is one of the idiosyncratic rituals and living history, at once both familiar and particular, which are a part of the life of the city. The great majority of people would prefer them to continue rather than quietly be forgotten."

The time ball was installed by Charles Piazzi Smyth, second Astronomer Royal for Scotland with the assistance of clockmaker Frederick James Ritchie in 1852.