Accession No

1703

Brief Description

diptych dial, French, 17th century

Origin

France

Maker

Class

dials

Earliest Date

1600

Latest Date

1700

Inscription Date

Material

wood (walnut?); ivory; metal (brass, steel)

Dimensions

87 x 97 mm; d (compass 55 mm)

Special Collection

Holden-White collection

Provenance

On loan from The Fitzwilliam Museum, University of Cambridge. Donated by Charles Holden-White to the Fitzwilliam Museum. Holden-White collection no. 1935-57.

Inscription

Description Notes

Wooden (?walnut) with ivory inlay and brass fittings.
Leaf 1a: Plain; pierced with holes to hold string gnomon with stamped latitudes for ‘40, 42, 45, 48’.
Leaf 1b: Decorated and marked in gold and silver, hand painted; four attachment points for string gnomon; list of towns and latitudes; brass levelling pendulum bob.
Leaf 2a: Horizontal dial calibrated on inset ivory anulus with four scales for 40, 42, 45 and 48. Hour scale divided IIII - XII, I - VIII, numbered by I, subdivided to 30 minutes. Inset compass with gold-painted rose, fleur de lys north, offset 7˚ E for magnetic variation.
Leaf IIb: plain.
poor condition, ivory very cracked
missing string, and lid detached

References

Events

Description
The Diptych dial is a common form of portable multi-function sundial. Diptych dials were made popular by the instrument makers in Nuremberg during the sixteenth and seventeenth centuries. They are usually made of ivory with brass fittings, and are often elaborately decorated. The name of the device derives from the Greek diptychos for a pair of folding writing tablets, which the instrument resembles.

Diptych dials consist of two leaves hinged together, with a string ‘gnomon’ stretched between the inner surfaces of the leaves for casting a shadow. To use the device as a sundial the lower leaf must be placed parallel to the horizon and the upper leaf must be at a right angle vertically to it. The gnomon must then be aligned with the meridian of the place where it is being used by using the inbuilt magnetic compass. Time can then be read from the horizontal or vertical dial by the location of the shadow cast by the string gnomon.

In addition to the horizontal and vertical dials, diptych dials normally carry a number of other features, such as equinoctial dials, windroses, tables of latitude for adjusting the string gnomon for different locations, epact tables, lunar volvelles for telling time at night by the moon, and various pin-gnomon dials for telling the time according to Babylonian or Italian hours, or for calculating the position of the Sun in the zodiac.
27/05/2009
Created by: Joshua Nall on 27/05/2009

FM:39809