Instruments · Universal equinoctial sundial

Sundial, made as a locket, gilt metal, part silver, 1¾-inches square, by Juan Cocart, Madrid, Spain, 1596 (see note).

DocumentedDocumented from the holding institution's catalogue record.

Maker / attribution: Cocart, Juan (maker)
Date: 1596
Historical period: Renaissance Horology (1400 – 1600)
Country of origin: Spain
Place: Madrid, Spain, Madrid
Object type: Universal equinoctial sundial
Dimensions: overall: 13 mm x 44.45 mm x 44.45 mm, .095kg
Holding institution: Science Museum Group, London
Accession / object no.: 1883-122
Credit line: Victoria and Albert Museum
Catalogue title (original): Sundial, made as a locket

Record summary

Held and catalogued by Science Museum Group, London (object number 1883-122), this is an universal equinoctial sundial by Cocart, Juan, made in Madrid, Spain, Madrid, dated 1596. The Atlas places it in the Renaissance Horology period (1400 – 1600) of its Instruments collection. Recorded dimensions: overall: 13 mm x 44.45 mm x 44.45 mm, .095kg. The record is illustrated with 1 photograph.

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.

Inscriptions & marks

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Historical context

Renaissance Horology (1400 – 1600)

Spring power makes clocks portable; Nuremberg and Augsburg produce the first watches; the Prague Orloj is built.

Instrument-making flourished in Nuremberg, Augsburg, Louvain and London: ivory diptych dials, astronomical compendia, astrolabes and nocturnals for wealthy patrons, navigators and scholars.

Read the period in the timeline More instruments from this period Earlier: Medieval Period

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.

What to look for

The latitude engraved on the dial plate or a latitude arc on the gnomon — it shows where the dial was meant to be used.
The type of hour lines: equal (equinoctial) hours, Italian or Babylonian hours counted from sunset or sunrise, or unequal temporal hours on early and Islamic instruments.
An inset magnetic compass and whether a magnetic-declination mark is drawn on its card — a useful dating clue because declination changes over time.
Maker's signatures and town marks: Nuremberg compass-makers (Kompassmacher) often struck a personal mark and the town's punch.
Additional scales such as lunar volvelles, wind roses, perpetual calendars or lists of cities with their latitudes.

Dating clues

Ivory diptych dials are characteristic of Nuremberg between about 1500 and 1700.
Butterfield-type dials with a bird-shaped adjustable gnomon point to Paris workshops from the late seventeenth century onward.
Equation-of-time tables engraved on the plate became common after the mid-seventeenth century, once pendulum clocks made the difference between solar and mean time obvious.

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.

Mechanisms mentioned

No escapement or complication is named in the source record. See the encyclopedia for how such pieces work.

Record completeness

Maker or attributionRecorded
DateRecorded
Place or countryRecorded
MaterialsNot in source
DimensionsRecorded
Narrative descriptionNot in source
Inscriptions / marksRecorded
ProvenanceNot in source
Several photographsNot in source

Editorial status: Documented — facts as published by the source; not independently verified by Atlas editors.

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Sources & image rights

Record source: Science Museum Group, London.

Image rights: CC BY-NC-SA 4.0 (Science Museum Group) — permission review.

Images are hosted by the Atlas for study and credited to their owner. Rights holders may request correction, credit changes or removal via the editorial office.

Cite this record

"Sundial, made as a locket, gilt metal, part silver, 1¾-inches square, by Juan Cocart, Madrid, Spain, 1596 (see note).." Science Museum Group, London, 1883-122. Catalogue record in The Horology Atlas, WatchMuseum.org, https://atlas.watchmuseum.org/museum/sundial-made-as-a-locket-gilt-metal-part-silver-134-inches-squar-1bb8d3.