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Mechanical equinoctial dial by Felice Gori, Italy, c. 1820 — view 1 of 2
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Instruments · Mechanical equinoctial dial

Mechanical equinoctial dial by Felice Gori, Italy, c. 1820

DocumentedDocumented from the holding institution's catalogue record.
Maker / attribution
Felice Gori (maker)
Date
c. 1820
Country of origin
Italy
Place
Florence
Object type
Mechanical equinoctial dial
Materials / technique
brass
Dimensions
diameter 133 mm
Holding institution
Museo Galileo, Florence
Accession / object no.
Inv. 3754
Credit line
Museo Galileo, Florence
Catalogue title (original)
Mechanical equinoctial dial (English)

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Record summary

Held and catalogued by Museo Galileo, Florence (object number Inv. 3754), this is a mechanical equinoctial dial by Felice Gori, made in Florence, Italy, dated c. 1820. The Atlas places it in the Precision & Scientific Horology period (1750 – 1850) of its Instruments collection. Materials and techniques recorded by the source: brass. Recorded dimensions: diameter 133 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

Catalogue description — Museo Galileo

The instrument, made by Felice Gori, consists of an optical tube that rotates and tilts by means of an arc. The tube rests on a disk whose angle with the base plate can be adjusted by means of a second arc. The disk is tilted to match the local latitude and the optical tube is pointed at the Sun so that the Sun's image is projected on the center of a small tilted ivory plate inserted in the tube. When the tube is oriented in this way, a window in the rotating disk shows the hour, while a mobile pointer displays the minutes on a circular scale. Provenance: Lorraine collections.

Provenance

Lorraine collections

Historical context

Precision & Scientific Horology (1750 – 1850)

Harrison solves longitude; Mudge invents the lever; Breguet's Paris workshop defines the modern watch.

The longitude problem was solved by the marine chronometer and lunar distance methods; dividing engines made precision scales possible, and observatories set time by transit instruments.

Read the period in the timelineMore instruments from this periodEarlier: Early Modern Horology

Atlas type guide

Scientific and navigational instruments

Timekeeping has always been tied to astronomy, navigation and measurement. Observatories used transit instruments to determine the exact moment a star crossed the meridian, and set their regulators by it; navigators combined sextant observations with chronometers to find longitude; surveyors, engineers and physicians used counters, pedometers and timers derived from watch and clock technology.

Instruments in this collection show how time measurement supported science and everyday technical life. Their makers were often the same workshops that produced clocks and watches, and their scales and dials document changing units and standards.

What to look for

  • Engraved scales and verniers; the units used (degrees, hours, decimal divisions).
  • Makers' signatures and town names, often on the main plate or limb.
  • Accessories and fitted cases that indicate the intended use.
  • Inventory or institutional marks from observatories, navies or schools.

Dating clues

  • Vernier scales spread after the seventeenth century; dividing engines after Ramsden (1770s) made fine scales common.
  • Mass-produced instruments with patent numbers belong mostly to the nineteenth and twentieth centuries.

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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