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Inventory no. 41486 - Epact entry

Epact number: 31953

Astronomical Compendium

Signed by Josua Habermel
Late 16th century; German
Gilt and silvered brass; 62 x 60 x 9 mm

Main text

Despite his family link with Erasmus Habermel, the instruments of Josua Habermel lack decorative sophistication and ingenuity.

This compendium is of a standard pattern, and includes an equinoctial sundial, a horizontal string gnomon sundial, volvelles and latitude tables. It is now incomplete: the rotating discs of the volvelles are missing.



Source museum: Museum of the History of Science, Oxford
Museum number: Inventory no. 41,486



Detailed text

The compendium has two approximately square hinged leaves enclosing a central box. Each leaf is fixed with a hook clasp. The only decoration on the sides of the central box is an incised rectangle.

The outer face of the upper leaf carries a circular compass rose with the eight principal directions named in German; in each corner of the face is an angel's head for the winds. The compass rose encloses an volvelle whose rotating disc is now missing. The remaining fixed scales are of hours 1 to 24, divided to quarters, along with a small scale section of hours 8 to 16, divided and numbered by 2. The volvelle would have been used to convert between equal and Italian or Babylonian hours, and to give the lengths of night or day respectively.

The inner face carries another incomplete volvelle, with foliage decoration in the four corners. The remaining fixed scales show that this was a typical lunar volvelle, with an outer scale of hours 1 to 12, 1 to 12 divided to quarters and an inner scale of the age of the moon 1 to 29 [|1/2|] which would have been seen through a window in the rotating disc. The centre of the circle is engraved to provide a visual indication of the age of the moon through a circular aperture in the lost rotating disc.

Hinged between the upper cover and the central box is a silvered equinoctial dial with foliage engraving in the corners of its dial plate. The hour scale is marked only on the upper face of the plate and runs 3 to 12 to 9, divided to quarters. The gnomon is missing and the plate is elevated by a folding arm on the face below. The underside of the dial plate has a scale marked 'Eleuatio Poli' with notches for 42, 45, 48, 51, 54°.

The central box of the instrument houses a horizontal string gnomon dial with hours from 4 to 12 to 8 and points for the half hours. The end of the gnomon is held in the equinoctial dial plate. Around the hour scale is further foliage engraving and in the centre of the face is a compass. The compass bowl is 322 mm in diameter and its base is marked in Latin with the four cardinal directions and with an indication of variation. The underside of the compass bowl carries an engraved classical head.

The inner face of the lower cover leaf has a circular table of the latitudes of 12 towns in the German lands, with foliate engraving in the corners.

The outer face has a square table of the latitudes of 18 places. It is titled 'Eleuatio Poli' and carries the signature 'Iosüa Habermel'.

Provenance: Lewis Evans Collection G. 410.

Stephen Johnston

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