A sundial is a device that tells the time of day from a shadow cast by sunlight. This varies during the day by the apparent position of the sun in the sky. In basic form, a sundial consists of a flat calibrated dial plate and a raised gnomon that casts a shadow onto the dial. As the sun “moves” in the sky during the day, the shadow aligns with different hour-lines, which are marked on the dial to indicate the time. There are many variations of types of sundials including single plane sundials that are oriented either vertically or horizontally, as well as other shapes and designs. A polyhedral sundial has multiple dials — one on each side other than the bottom. For any side exposed to the sun as it “moves” during the day, the time shown by the shadow cast by the gnomon is accurate. Other sides that are in the shadows during certain times of the the day (and of course at night) are periodically then not in use inasmuch as without sunlight they do not show the time at all.
Polyhedral dials are associated with Renaissance astronomy in the 16th and 17th centuries. They served as ingenious demonstration pieces showing the skill and knowledge of mathematicians and instrument makers who designed them. They were status objects for their owners to show their interest and appreciation of different aspects of math and science. They have been made with varying numbers of faces and shapes, ranging from regular polyhedral with all equal faces, to highly irregular shapes. Some had plumb bobs or inset compasses for orientation.
David Beringer was an instrument maker in Nuremburg, best known for producing polyhedral sundials, which became popular in South Germany in the latter half of the 18th century. According to the National Maritime Museum at Greenwich, Beringer was likely the first person to produce a polyhedral dial with a cube design. According to the Liverpool Museums, the Berringer cube polyhedral dial in their collection is used as follows:
Condition: Generally very good with the usual overall light toning, handling, and wear. Paper tones vary somewhat on different sides, with the greatest wear and darkening on the top of the dial and on base.
“Cubic Sundial.” National Museums Liverpool. http://www.liverpoolmuseums.org.uk/kids/games-quizzes/sun/sd3_moreinfo.html (9 April 2018).
“Polyhedral Dial.” Matrix: Maths and Technology Revealed in Exhibition. http://www.counton.org/museum/floor2/gallery4/gal3p2.html (4 April 2018).
“Polyhedral Dial.” Royal Museums Greenwich. http://collections.rmg.co.uk/collections/objects/10547.html (4 April 2018).
“Portable cube sundial.” Metropolitan Museum of Art. 2000-2018. https://www.metmuseum.org/art/collection/search/188836 (4 April 2018).