Surveying quadrant, 1674.
© Science Museum / Science & Society Picture Library
This quadrant, with sights, plotting scales and a gunnery scale on the obverse, was made in Rome by Jacob Lusuerg in 1674 and bears the coronet and arms of the Duke of Modena. Many members of the Lusuerg family in Rome were instrument makers, and several of them are represented in the Science Musem collections. A small version of an astronomical instrument, the gunnery quadrant measured vertical angles to give the altitudes of terrestrial objects and for setting artillery.