front and back of an ivory diptych dial
Front and back of a diptych dial

Amazingly, fragments of at least four diptych dials have been recovered from James Fort including one in May 2012. These small, fragile artifacts are made of ivory, and their survival on archaeological sites is rare. Only one of the fragments recovered by Jamestown archaeologists is inscribed with the maker’s name, that of “Hans Miler” (in historical documents, the name is also spelled Miller). The Miller family were known compass and diptych dial makers in Nuremberg, Germany in the early 17th century, and it seems likely that all of the James Fort dials came from a similar source. The engraved numbers, letters, and symbols are still visible on many of the fragments. However, colored pigments like cinnabar, once rubbed into the numbers and letters so they were legible, are no longer present.

Diptych dials, also called pocket sundials, were primarily used to tell time. Like a diptych painting (or today’s flip phones), two hinged leaves opened to reveal at least one, sometimes two dials and occasionally other markings to help orient the user. The lower leaves found at Jamestown are engraved with Roman numerals representing the hours of the day and dots representing half hours. The numbers and dots are oriented like today’s clocks with 12 at the top, close to the diptych’s hinge. The two leaves were connected by a gnomon string, ensuring that they opened at the correct angle to each other. A centrally-inlaid magnetic compass would have been present on the interior of the lower leaf. None of the diptych dials found at Jamestown still contain the gnomon string or the compass. Yet, some fragments demonstrate empty holes for the gnomon string and a carved depression for the compass. A glass lens recovered from the factory is thought to belong to a compass from a diptych dial, and a degraded magnetic compass recovered from a mixed context, now missing its N-S meridian pointer, is also thought to belong to a diptych dial.

To use a diptych dial, the user held the open compass on a flat surface so that the lower section was parallel to the horizon. The gnomon string was aligned with the N-S meridian on the compass, ensuring that the instrument was held in a north-south orientation. Sunlight on the gnomon string cast a shadow, falling onto one of the numbered hours or the half-hour dot. This provided the local time. Just like on a sundial, as the sun moves during the day, the shadow’s position on the dial changed. 

Each diptych dial was made to be used at a different latitude with some manufactured to allow travelers to move the central gnomon to different holes on the top leaf depending on their location in the world. The most intact fragments at Jamestown are the lower leaves, so it is unknown if they were adjustable to different latitudes. The usual latitude for non-adjustable Nuremberg dials is approximately 48°, which would provide accurate measurement across most of central Europe. Calculations of the existing dial angles of two of the lower leaves of diptych dials found at James Fort indicate that they were manufactured to be used in Venice, Italy. Unfortunately for the owners at Jamestown, which has a latitude of 37°, these once useful tools did not provide a very accurate local time.

Most of the diptych dial fragments found at Jamestown were discarded by c. 1610 in early fort period features, including the factory, the first well, and the kitchen and cellar. Thus, archaeological evidence supports the theory that diptychs were not as useful in Virginia as in Europe or during a seafaring voyage.

While diptych dials would have been useful tools for travelers, they were possibly popular for an entirely different reason. Possession of a diptych dial would have signaled that the owner of a dial was a wealthy, scientific-minded individual who was well-educated, well-traveled, or both. This tiny instrument placed the world in the hands of a gentleman engaged in the art of “dyalling.” One such gentleman was John Smith, who possessed a “round Ivory double compass Dyall.” By harnessing the power of the sun through the tiny gnomon string, Smith understood that he was a part of a much larger universe, in which the globe, the sun, the moon, and the stars were all connected and operated with clockwork-like predictability. Created in an age of scientific and philosophical exploration and discovery, this small artifact encapsulates the worldview of some of Jamestown’s earliest colonists.

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