BOXWOOD GUNTER'S QUADRANT
English, 17th century, 3/8" thick, 7" radius, with central hole for pillar mounting. Face of quadrant engraved and stamped with Gunter's design, first described in 1623, and laid out here for 52° latitude. Months indicated on calendrical scale with stamped capital letters below unusual stamped crown/anchor designs. Reverse side scratch engraved with an early unfinished design of calendrical/Zodiacal circles (for a pre-1752 vernal equinox of March 10) as well as an angel and castle decoration. Some slight warping, and loss of edge sights.
An early example of the English Gunter's quadrant. Quadrant were a practical, portable instrument used to carry out astronomical calculations sun as finding the time of day or the sun's azimuth, to observe astronomical phenomena, and to perform the basic tasks of surveying.
See Bennett, The Divided Circle: A History of Instruments for Astronomy Navigation and Surveying (Oxford: Phaidon, 1987), pp 79-80.