This small slate fragment is incomplete, and we may never know what its original use was, but the rayed lines etched on its surface appear similar to the lines found on a sundial.
While sundials have been in use from ancient times, Europe in the late 16th and early 17th centuries experienced an explosion of interest and study in astronomy and tracking and keeping time. Timekeeping devices for use while traveling aboard ships were invented and perfected, and handheld, custom designed items made to be used at specific locales throughout the world, like diptych dials became relatively common. In England, King Charles II supported these endeavors through the creation of the Royal Observatory in 1675, which later became the location for the prime meridian.
Although timekeeping remained imperfect, a number of books, papers, and treatises were published beginning in the late 16th and throughout the 17th century describing various types of sundials and the calculations involved in their creation. The plethora of published work indicates just how popular the sundial was at the time. Sundials are still used today as decorative and functional elements in town centers and gardens, including one which was installed in 1907 in the front garden of the historic Yeardley House, which now serves as the research center for the Jamestown Rediscovery Foundation.
Slate was not an uncommon resource in England, and was most commonly used in writing tablets, like the one found in James Fort’s second well. But because slate is relatively easy to incise, it makes an ideal material to manufacture a sundial.