Diptych sundial (detail)

Add to album

Diptych sundials have two plates hinged together, and in use open out to form a right angle, with the string hinge operating as a gnomon. This ivory example was made in the 17th century in Dieppe in France. The photograph shows the inside of the lid.

The lunar or tidal volvelle is a circular brass disc graduated from 1 to 31, working inside a ring graduated 1-12 twice. It was used to discover the time of high tide in a given port, using the known lunar cycle.

This part of the dial is particularly found in French diptych dials. The inhabitants of the largely land-locked German cities would have no use for such a device.

Record details

To search on related items, click any underlined text below.

• Online ID: 000-190-001-023-C
• Image Rights Holder: National Museums Scotland
• Project: National Museums Scotland
  Project description   View all records in project
• Ref: National Museums Scotland  T.1924.11
• Date: 17th century
  
• Material: Ivory, paper list, brass strut and disc. Inscription: [On base] List of places and latitudes
  Sundial, universal, portable
  
• Dimensions: 2.75" x 2.25"
  
• What: Sundial, universal, portable
  
• Subject: 20. TIME MEASUREMENT, Sundials (Departmental Classification)
  
• Who:
• Where: France, Dieppe
  
• Event:
• Description: French portable universal sundial in ivory, book form, base with sunk compass, horizontal dial and list of places and latitudes, with equinoctial dial on lid, unsigned, Dieppe, 17th century
  
• References:
  • For a comparable example, see Lloyd, Steven A., Ivory Diptych Sundials 1570-1750. London & Cambridge, Massachusetts: Harvard, 1992. p 136 
  • Turner, G. L'E. Antique Scientific Instruments. Poole: Blandford, 1980. pp 22-3 
• Translations:
• Related Records: