Hidden miracle of Louis XV's millennium clock

AT MIDNIGHT French time on 31 December of this year, while most of Paris is going crazy on the Champs-Elysees, a clock-work miracle will occur unseen at the Chateau de Versailles.

A clock built 253 years ago, to show days, months and years as well as hours and minutes, will tick-tock its way without fuss or fanfare into the new millennium. The first digit on the year-counter, which has been stuck on "one" for the past two-and-a-half centuries, will move smoothly and silently on to "two". The other digits will turn to zero and the clock - sometimes called the 10,000-year clock - will have entered a new millennium, without "bugs", expensive readjustments and precisely on time. What price new technology?

Other year-counting clocks exist in various parts of the globe. None is believed to be as old as the Horloge Passemont in the Chateau de Versailles and none, certainly, has mutely witnessed as many of the decisive events of the past quarter-millennium.

The clock was bought by Louis XV in 1749, three years after it was constructed. It has stood ever since in the "clock room" at Versailles, a few yards from the rooms occupied by Louis XVI and Marie-Antoinette at the time of the Revolution; and only one room away from the Hall of Mirrors where the peace treaty to end the First World War was signed in 1919.

The clock's present custodian is the chief clock-keeper of the chateau, Daniel Mornas, 61, who visits his charge once a month to wind it. When he reads of all the anxiety about the millennium bug, Mr Mornas says he smiles but "it also makes me angry".

"It is absurd, inadmissible that all these expensive, clever, modern machines should have been made without bearing the millennium in mind. Was it just stupidity or for commercial reasons?"

Mr Mornas, owner of a clock workshop in the town, is a precise, passionate, sombre-seeming man, given to bursts of infectious enthusiasm for his trade. His life is ruled by the clock: or by more than 200 clocks, most of which need to be rewound every fortnight. "Whatever else happens in my life," he said. "I know that I can never go on holiday for more than two weeks."

The Passemont clock, named after its creator, a celebrated French clock- maker, loses one minute a month. "I could try to adjust the mechanism but, in my view, for a clock that old, to lose a minute a month is not so bad. So I just move it forward a minute each month and otherwise leave it alone," Mr Mornas said.

We visited the clock outside normal visiting times. The chateau, the largest and many believe the most beautiful mansion in the world, was eerily and movingly empty. The light was just fading on the huge, geometrical gardens beyond the Hall of Mirrors. The clock, in an ornate brass case, about six feet tall on a plinth of marble, stood awaiting its moment of technological triumph in a room which most visitors do not see.

The mechanism, including more than a thousand interconnecting brass and steel wheels, was constructed to take account of the differing numbers of days in each month and adjusted, in advance, for leap years. There is one large brass wheel in the clock, which takes exactly four years to perform a full revolution. When it does so, it trips another wheel which provides February with its 29th day. In all other years, the clock moves automatically from the 28th of the month to the 1st of March.

The clock also records, accurately, the phases of the moon, and beautifully but less accurately, according to the slightly wayward calculations of Copernicus, the movements of the planets. The 10,000-year clock is so- called because it is capable of counting the years up to 9999. Mr Mornas does not like that name: he doubts that the clock will see one more millennium, never mind another 8,000 years. "Given normal wear," he said, "I expect that it should last another 500 years but not much more than that."

Seven centuries is not bad. Why should Monsieur Passemont - his first name has not come down to posterity - have built a clock capable of surviving for 750 years?

"Because that was the mentality of the age," Mr Mornas said. "You see it also in the buildings of the time, like this chateau. Everything was made to last indefinitely. In our own time, when we build a school or a hospital, we expect to tear it down after 20 years and start again. Everything is for the moment ... In those days, there was a sense of permanence, a sense of eternity. It's something that we've lost."

No special event is planned to mark the moment when the clock ticks into 2000. Unless one of the chateau caretakers bothers to witness the moment, a technological feat, pre-programmed two-and-a-half centuries ago but seemingly beyond our greatest modern brains, will occur in the dark - and unseen.

John Lichfield