14th century pocket calculator found in Canterbury fetches world record price at Bonhams

A new world record price was achieved today (21 March 2007) at Bonhams’ salerooms in Knightsbridge London. One of the world’s most significant archaeological discoveries of recent times of a scientific instrument fetched £138,000. It sold to an anonymous telephone bidder after a lengthy battle against a number of buyers present in the room.

The incredibly rare 619 year-old instrument, which attracted a bidding frenzy, was the pocket calculator of the 14th century – able to measure the height of a building, the depth of a well, or accurately date when the next Easter moon would fall.

A Canterbury Tale…

In 2005, during excavations for the extension of the Canterbury-based hotel, restaurant and bar Fusion, an unusual discovery was made. A scientific instrument known in the middle ages as the ‘quadrans novus’ – today, often labelled as the ‘astrolabe quadrant’ – was found on a site known as the ‘House of Agnes’, a 17th century inn on the main road to London, just beyond the Westgate of the city. There it lay beneath a series of clay floors, inside a sealed soil deposit dated to circa 1375-1425.

Now, two years on, the astrolabe quadrant has been dated to circa 1388 – one year after Geoffrey Chaucer started to write The Canterbury Tales. Chaucer was familiar with the function of a quadrant, writing a ‘Treatise on the Astrolabe’ in 1391.

This quadrant is one of only eight examples known in the world. It was made in England and is one of the oldest and smallest in existence.

Following the sale, Bonhams’ director of Scientific Instruments, Jon Baddeley, said: “It was a privilege for Bonhams to handle such a historically important artefact. It is extraordinarily rare to find a scientific instrument of such an early date and impeccable provenance at auction.”

The brass quadrant has two sight vanes on one edge and there is a suspension with a hole for a silken cord with a bead (now lacking) on the front of the instrument. On its back two concentric circles with calendar data can be seen, with an eagle – its wings spread – sitting in the centre of the rings.

Once upon a time, the bird – known for its ability to look directly at the sun – would have been able to revolve. Its tail, feet and wing tips would have moved over the various scales, making it easy to calculate the date of the Easter Moon. The instrument could also tell the time of day (during sunlight hours), the length of day and night, and the height and depth of structures and objects.

The vendors of the quadrant – the directors of Fusion hotel, restaurant and bar – were in the saleroom when the quadrant came under the hammer. Commenting on their behalf after the sale was Fusion’s marketing director, Stephen Wade who said: “We would like to thank Bonhams for hosting the sale of such a treasured item. It has been an honour to have a device of such historical interest pass through our hands.

“Part of the proceeds from the sale will be used to create a permanent exhibition at Fusion, describing the historical, social and scientific context of the quadrant. A further sum will be donated to our adopted charity, Demelza House Children’s Hospice, supporting the Capital Appeal to build South London’s first residential Children’s Hospice, that will help over 800 children with life limiting conditions.”