Pocket Compass Sundial, Spanish

Title: Pocket Compass Sundial, Spanish
Date Created: c. 1560
Creator: Unknown
Identifier: Wh.6794
Original Location: Made in Spain, and later modified, possibly in South or Central America, for use in New World
Current Location: Cambridge, United Kingdom
Description: As with all pocket sundials, this instrument is made for travel. It carries a compass needle so that it can be aligned north-south, and its outer casing is engraved with the latitudes of many major European cities so that its shadow-casting gnomon can be adjusted as its owner moves. The predominance of Iberian cities in the latitudes list, and the presence of Antwerp as one of the four cardinal cities of Europe, suggests that it is Spanish-made and pre-dates the protestant reformation of Antwerp in the late 1560s.
A second set of evidence points to the instrument’s global travels. The underside of the dial’s case has been heavily modified by a second artisan sometime after its original manufacture. A second set of city latitudes has been added, in a less assured hand. Remarkably, all of these cities are in the ‘New World’, and include both major Caribbean, Central, and South American cities (Havana; Mexico City; Lima; Quito), as well as many smaller and more obscure cities from across the north and west of the continent. Research links many of these cities to Spanish mining concerns; and so the dial appears to have been modified for use by a Spanish conquistador. Because this second latitude list cannot be matched to any known atlases or geographical texts in Spain, it is plausible that these modifications were made by an artisan working in Central or South America.
Credit: Image (c) Whipple Museum, Cambridge (Wh.6794)
Link: https://collections.whipplemuseum.cam.ac.uk/objects/15683/
Contributor: Dr. Joshua Nall, Director and Curator, Whipple Museum of the History of Science, University of Cambridge