Diptych Dial

ALL SAINTS . MAIDEN BRADLEY (∏ Retired QA)

ALL SAINTS . MAIDEN BRADLEY . WILTS

GRADE I ♱ Saxon foundation. C12 (first record 1102) early C14, C15, 1845 restoration. C12 Purbeck marble font bowl. Jacobean box pews. Spiritual home of the Dukes of Somerset, duly commemorated. Original 14th century oak door, fittings. Scratch Dial featured HERE. 7m SW of Warminster. Longleat & Stourhead nearby. 51.1468 / -2.2821 / ST803386

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DIAL

All Saints has an unusual and intriguing double-faced sundial above the porch, thought to be C18. At first sight, looking towards the porch, it could be a cube dial. The 2 sides are at right angles facing SE and SW. Between them, they cover the ‘6-to-6’ time span. There are faint markings on the dial faces – roman numerals, lines (see below).

BSS records two declining dials of similar design believed to be made from one sheet of metal folded at the centre. Between them they show 6am to 6pm in half hours.

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SOUTH ASPECT

It is worth noting that the two gnomons are matched in both style, and position on each face. This is only (I think) possible with equal SE / SW angles. BSS notes SE dial may be ‘slow‘.

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SOUTH EAST ASPECT

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SOUTH WEST ASPECT

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DIAL MARKINGS

A poor photo enlarged, showing the visible markings – lines and the reciprocal roman numerals at the edge of each face.

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SCRATCH DIAL HERE

GSS Category: Scratch Dial; Mass Dial

All photos Keith Salvesen except header, Retired QA (OS CC)

A diptych dial is a type of sundial with two hinged leaves which open like a book to use shadows cast by the sun to tell the time.

When opened, a cord holding the top leaf of the dial in its upright position acts as the gnomon. The dial is put on a horizontal surface and orientated so that the gnomon is pointing towards true north. This is done with the help of a compass embedded in the horizontal leaf within the main dial. As the Sun moves round, the shadow moves across the dial marking the passage of the day. Times in places of significance can also be calculated from the dial’s readings. MHS.OU

These beautiful pieces were intricate and costly, often made using ivory. The dial shown here is my own. I’d love to be able to say that it is a rather rustic version of a valuable diptych dial, but it is in fact a cheap knock-off from eBay that I bought to test the workings… or is it the real deal?

There are many museums with watch and clock collections – for example (in the south) Oxford (Museum of the History of Science), London (V&A, Science Museum), and Greenwich (Maritime Museum).

3 PRECIOUS IVORY DIPTYCH DIALS