Stock Number: 7206


For sale, antique 18th century dial in a shaped fruitwood case. This is a most unusual dial by Peter Onions recorded as a clock maker in the middle of the 18th century.


3 x 4 inches (8 x 10 cm)



Country of manufacture

UK and Ireland

Categories: Timekeeping, Portable Sundials


UNUSUAL HORIZONTAL DIAL, English, 1789, signed “Onions, 1789, Lat. 51°30′.” The 3″ x 4″ (8 x 10 cm) brass dial is set into a tabernacle-shaped fruitwood carrying case, complete with early handwritten equation of time table. The brass dial itself is beautifully executed, the folding gnomon pierced and engraved with floral design, the chapter ring divided every five minutes, the inset compass surrounded by engraved vines and flowers, the glazed compass itself with engraved brass compass rose and finely cut needle. To the west of the fleur-de-lys North point is an engraved “V” and “27,” indication of the point of magnetic variation. (In fact, consulting a plot of variation vs. time and place, we find, for London, the declination in 1780 was 23° West and heading further west at about 0.15 degrees per year ‹ as it had been doing for the previous 200 years. Thus Onions, in 1789, could have anticipated a variation of 27° about 20 years later, and constructed a dial made to last. In fact, the actual variation slowed down and, reaching a peak about 1810, then reversed direction, and now approaches 0° in London. It never made it close to 27°!) Condition of the dial is very fine, noting a crack and water (?) damage to the wood base. The maker, presumably Peter Onions, is listed in Loomis as a clockmaker working in Brosley c.1760. He gave his own distinctive, rather elegant design to the dial and its decoration. The overall shape, in fact, mimics that of a standing clock! Most unusual. 

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David and Yola Coffeen both have enjoyed academic careers, as planetary astronomer and as linguist/educator. But since 1982 (yes, 1982!) they have been full-time dealers in early scientific and medical instruments, under the name Tesseract. Selling primarily by catalogue (over 100 issued so far) they also have a web presence at www.etesseract.com, and can be contacted at [email protected].

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