Saturday, November 15, 2008

King's Lynn Tide Clock

click photo to enlarge
On each of the two, tall towers of the west front of the medieval church of St Margaret's, in the Norfolk port of King's Lynn, is a clock. One has a conventional face with Roman numerals: the other has 12 letters that appear to be randomly placed. Until, that is, you read them clockwise from the "L", when they spell out the words "Lynn High Tide"!

This clock is a faithful twentieth century reconstruction of the original design of Thomas Tue's 1681 clock made to show the ships in the port the time of the local high tides. The dragon pointer of the clock completes a full rotation every 29.5 days. Letters mark the even hours, and the intervening triangles and red dots the odd hours, of the 24 hours of the day. Thus "L" is noon, and "G" is midnight. If the pointer indicated a high tide at "H" (2 a.m.), then the opposite mark ("Y") would be almost the time (within 25 minutes) of the next high tide. A mechanism also controls the moon that revolves eccentrically behind a hole and indicates, by its position, the lunar phases. The blue inner disc is fixed to the dragon pointer.

Tue's original clock was damaged when the church's spire collapsed in 1741, and was poorly maintained thereafter, eventually falling into disuse. This reconstruction was made under the direction of the architect, Colin Shewring, and is a fascinating reminder of the early technology that sailors used.

photograph & text (c) T. Boughen

Camera: Olympus E510
Mode: Aperture Priority
Focal Length: 150mm (300mm/35mm equiv.)
F No: f6.3
Shutter Speed: 1/200
ISO: 100
Exposure Compensation: -0.7 EV
Image Stabilisation: On