Horizontal and analemmatic sundial, "Engelbrecht, 1800" (plummet missing)

Record summary

Held and catalogued by Science Museum Group, London (object number 1938-420), this is an analemmatic sundial by Engelbrecht, Johann II, made in Beaune, Côte-d'Or, Burgundy, France, Beaune, dated 1800. The Atlas places it in the Precision & Scientific Horology period (1750 – 1850) of its Instruments collection. Recorded dimensions: overall: 25 mm x 154 mm x 180 mm. The record is illustrated with 2 photographs.

Assembled from the source record's structured fields. Dates and attributions are given as the source states them; where a field is missing the Atlas leaves it blank rather than estimating.

Catalogue description

The source record does not include a narrative description. The structured fields above are reproduced from it.

Atlas type guide

Sundials and solar time-finders

A sundial tells time from the position of a shadow cast by a gnomon or style. Because the sun's apparent motion depends on latitude, every fixed dial is laid out for a particular latitude, and portable dials either carry a latitude scale or are made for one region. Sundials show local apparent solar time, which drifts against mean (clock) time by up to about sixteen minutes over the year — the equation of time.

Portable dials were the pocket instruments of the sixteenth to eighteenth centuries. Nuremberg and Augsburg workshops produced folding ivory diptych dials with inset compasses; English and French makers sold brass horizontal dials, ring dials and the Butterfield type; Japanese and Chinese makers had their own traditions of compass dials. After mechanical watches became reliable, dials remained in use for setting them, and nineteenth-century heliochronometers were built to correct directly for the equation of time.

General guidance written by the Atlas editors about this kind of object. It is not a statement about this particular piece; for that, rely on the source record above and on physical examination.

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