BRASS & SILVERED BRASS MECHANICAL SUNDIAL FROM GERMAN LORRAINE, CA 1750

A 7 x 5 1/2 x 5 in (when folded for travel) complex mechanical universal sundial in brass and silvered brass with decorative piercing and turning of the brass, and finely shaped finials and sights. 5 1/2 inch diameter ring gear, inset compass, target arm, minute hand (which operates a pinion gear against the ring gear) hinged plumb bob staff, thumb screws, and hinged leg which locks over latitude arc to raise the dial. 

Tesseract Catalogue 55, 1996/1997, item 18

A WONDERFUL AND VERY RARE COMPLEX MECHANICAL UNIVERSAL SUNDIAL, ONE OF ONLY THREE KNOWN EXAMPLES BY THE MAKER GASPARD. To operate the dial, one sets the inclination for the proper latitude, orients it using the inset compass, levels the dial using the plumb bob and thumb screws, tilts the target arm for the proper solar declination (as indicated by the slit shadow), and rotates the minute hand until sunlight falls through the slit directly onto the target line. The time is then indicated by the chapter ring readout window and the minute hand. Lunéville was an important city of Lorraine, and home to a flourishing interest in science during the 18th century thanks to Duke Leopold and Stanislaus I (1677-1766), the former King of Poland and founder of the Academia Stanislai in Lunéville.