E0757

Universal equinoctial ring dial Long Caption: Universal equinoctial ring dial for latitudes 0°-90° north. It is for use in northern latitudes only. A slider moves in the grooved rim of the meridian ring and a pointer on the slider indicates the latitude. On the obverse side of the meridian ring, there is a latitude scale and the remainder is filled with a table of latitudes, primarily listing places in Britain and France. On the obverse side and the inner rim of the equinoctial ring are hour scales, while on the reverse there is another table of latitudes comprising places in England. The bridge has a date scale in months and the equinoxes are marked at 11 March and 12 September. This dial was made by Elias Allen, the first maker of universal equinoctial ring dials. Allen was a friend of William Oughtred, their designer. It carries fewer scales than the later ones, and has no altitude quadrant unlike many other English instruments. Allen was sometimes careless in his engraving of numbers. For example, as we see here, the latitude of Cambridge was first engraved as '52 26' and then corrected to '52 16'. The sundial is signed 'Elias Allen fecit' on the obverse side of the equinoctial ring. Credit line: © National Maritime Museum, Greenwich, London Object: AST0207 Artist: Elias Allen Date: circa 1635 Medium: brass Size: 4 mm x 64 mm Click here to buy a bespoke print of this image.