Indoor: Clocking the sun

If you want to use a sundial to tell the time, writes Caroline Donald, make sure it is custom-built for your garden - or you may find inaccuracies creeping in

As we hurtle towards the year 2000, how we measure time gains a special significance. So it was with a sense of satisfaction that I sought out David Harber, maker of sundials, at his Oxford workshop. The millennium bug may be a cause of increasing concern, yet the sun will rise and set regardless of computer crashes, and Harber's dials will continue to measure the hours, using methods first discovered thousands of years before Christ effectively started the whole millennium business.

Harber's works range from a simple obelisk that casts a shadow on markers set in the ground, to a copper hemisphere resembling a tilted mortar that is engraved with the hours and the tropics of Cancer and Capricorn and owes its origins to Berossos, an Egyptian priest, who worked out the earth's circumference to within 500 miles, 300BC. "Over here, in AD1400 we still thought that we would fall off the edge," says Harber.

Having left Dartington school at 15, Harber discovered at first hand that the Earth is round when he learnt to fly. Meanwhile he also acquired metalwork skills while running a travelling theatre group on a boat in France. And then "it all suddenly gelled. I bought a book on how to make sundials and the end result was my first armillary sphere, which was snapped up." Today, these armillary spheres, which look like a cross between an old-fashioned globe and a ball of string, are his best-selling line, with prices from about pounds 1,500 for a brass one (they also come in bronze and stainless steel). This may seem a bit steep, but all his dials are custom-built, and marked with mottoes and measurements that are important to the client.

"You can move them to a degree," says Harber, relishing the unintentional pun, "but they need to be in the exact location to work absolutely accurately. You can move them north and south quite easily, but they start to get inaccurate if you shift them east and west. For instance, there is a four- minute difference between the time when the sun is overhead in Greenwich and in Oxfordshire."

From the spot in Greenwich or Oxfordshire, Edinburgh or Timbuktu, the dial can be inscribed with the exact direction and number of miles to a significant place for a client anywhere in the world. "Invariably, they are exotic," says Harber. "We don't get many pointing to Milton Keynes."

The tradition of mottoes goes back to the days when sundials were the only form of time-keeping in a community, and where usually erected by the local squire or a scholar. "They were seen as oracles, the voice of something ethereal and spiritual," says Harber.

He provides a list for clients taken from dials of the past, usually exhorting the reader not to be a wastrel, or reminding him in a cheery way that death is just around the corner, though the translation given for carpe diem - Ah, take the cash in hand and waive the rest - is more an example of the blithe sense of humour of Harber and his wife Sophie (who runs the business side of things) than of their linguistic skills.

Although they look simple, Harber's wall-mounted dials, similar to those you see on churches and manor houses, are painstakingly calculated for that wall alone.

He is as polite as he can be about the mass-produced sundials you can buy at garden centres: "It's nice that people are interested, but it seems a shame to spend your money on something that doesn't fulfil its purpose. There was a batch that came over from the Far East, where the gnomen [the shadow-caster] had been made for an obscure latitude somewhere below the latitude of the south of France, and fixed the wrong way round, so they were never going to tell the time."

At the moment Harber is making a slate-and-copper wall dial especially for his stand at the Chelsea Flower Show. It has been mathematically calculated exactly to mark noon for the occasion - a risky move, but an impressive one if it comes off, in front of the world's smartest horticultural clientele.

When we met, Harber was about to set off for Chicago to unveil an armillary sphere for a bank, then on to Martha's Vineyard for another installation. "Most of the people I meet are really interesting," he says of his necessarily financially comfortable clientele (though prices start at a not-too-unreasonable pounds 500). "They want to put some thought into what they are commissioning. What you say on a dial should be done glibly; it is going to be there for quite a while."

In June, he completes a sundial for a private client made from monoliths of 150-million-year-old Jurassic stone that will mark the positioning of the planets around the sun at dawn on 1 January, AD2000. It will take 27,000 years for these positions to repeat. Now that is quite a while.

David Harber Sundials (01491-576956; fax: 01491-413524; e-mail: sales@harber- sundials.demon.co.uk; website www. harber-sundials.demon.co.uk)