Smithsonian Collection - Pocket sundial by Bourgaud of Nantes, 1660–1675. (MA.325565)

From the National Museum of American History is an article about "How did a French pocket sundial end up buried in a field in Indiana?" published 20 July 2022 by Kidwell & Schechner.  

It started in 1860 when Dr. Elisha Cannon, while plowing a field in Indiana, came across a strange object. It was a French Butterfield sundial. It ended up in the Smithsonian collection 100 years later, where it quietly sat until recently when curator Peggy Kidwell wanted to learn more. She contacted Dr. Sara Schechner, David P. Wheatland Curator of the Collection of Historical Scientific Instruments at Harvard University, to join the investigation.

The dial is inscribed "Bourgaud Nantes" showing it was from the workshop of a clockmaker in Nantes, France. As with all Butterfield dials it contained a magnetic compass with declination corrections for orienting the dial to north and a miniature plumb bob to hold the dial level. The gnomon support is in the traditional shape of a bird allowing the gnomon itself to be adjusted to a range of latitudes. Look closely at the chapter ring of hour marks in Roman numerals.  Outside the numerals is one hour line scale and on the inside of the numerals is a second scale.  The user could approximate the time between these two scales, done for the extreme latitudes 30 and 55 degrees.

"In her research on sundials in the American colonies, Schechner has drawn attention to several of these dials, and notes that some 18th-century French sundial makers, like Pierre le Maire (and his son of the same name), made pocket dials that carefully listed the latitude of places of French interest in both North and South America." How did the dial end up in Indiana? It could have been carried there by Dr. Cannon and his wife Gulielma, Quakers who in 1840 left North Carolina, finding that "living in a state where African Americans were legally enslaved was intorable." Or the dial may have been left a century earlier when the French occupied much of what is now Indiana, leaving outposts such as Terre Haute and possibly a lost sundial.

Read the article: https://americanhistory.si.edu/blog/pocket-sundial