Diptych Dial by Hans Troschel

Technical characteristics

Date

1584

Type

Nuremberg diptych dial

Maker

Hans Troschel

Material

Ivory and brass

Dimensions

62 x 16 x 11 mm

Place recorded

Nuremberg

Place of origin

Nuremberg

Compass markings

SE, OR, ME, OC

Maker / attribution

Hans Troschel

Design

Visible features

• The glass cover over the magnetic compass is cracked. • The dial is densely engraved with gothic script and color-coded hour markings in red and green. • The object includes a folding mechanism joining two ivory leaves with a string gnomon. • The maker's signature and date 1584 are clearly inscribed on the inner upper leaf.

Timekeeping Features

The instrument functions primarily through string and pin gnomon dials. The string gnomon is adjustable to four specific latitudes, allowing the user to select the setting closest to their geographic location. Instructions for this adjustment are provided directly on the dial in gothic script, translated as 'firstly put the string into the slotlet according to the pole of your country or which is the nearest to it'. The dial tracks time using several different systems. The pin gnomon dial on the upper leaf displays Italian hours marked 13 to 24, and Babylonian hours marked I to XI. The lower leaf includes a string gnomon dial tracking common hours from 4 to 12 to 8, and a further pin gnomon dial showing Italian hours from 10 to 23 and common hours from VI to XII to VI. The sun's declination is denoted by zodiac names.

Construction and Design

The diptych dial is a portable instrument fashioned from ivory and brass, measuring 62 mm by 16 mm by 11 mm. The instrument consists of two hinged leaves that fold together. The interior surface of the upper leaf is populated with a pin gnomon dial, lists of geographical locations grouped by latitude, and various time scales including Italian hours in red ink and Babylonian hours in green ink. It also displays day and night length indicators. The lower leaf contains a circular compass inset with cardinal points marked as 'SE', 'OR', 'ME', and 'OC'. Additionally, the lower leaf incorporates a string gnomon dial with four distinct rings corresponding to latitudes 45, 48, 51, and 54 degrees. The exterior of the lower leaf features the maker's punch mark, repeated three times, and the Nuremberg quality mark 'n'. The outer face of the upper leaf features a lunar volvelle with scales for time correction in hours and minutes. The borders of this section are marked with the cardinal points, and it includes a list of cities corresponding to latitudes 51 and 54 degrees.

Signatures and Provenance

The dial is signed by Hans Troschel, with the specific inscription 'HANS DR?SCHELL NORMBERG FACIEBAT [star] 1584' located on the bottom of the upper leaf. The object is catalogued by the Museum of the History of Science, Oxford, under inventory number 82451. The maker's attribution is supported by both the signature and the quality mark 'n' for Nuremberg found on the exterior of the lower leaf, confirming its geographic origin within the context of 16th-century ivory sundial production. The instrument is documented in the reference work by P. Gouk regarding Nuremberg ivory dials.

Identification

Inventory number

82451

Source note

Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.

Catalogue references

No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.