Description

SIGHTING QUADRANT, English, c. early 19th century. This all-brass instrument stands 6-1/4″ (16 cm) tall, with cross-hair equipped sighting tube moving in altitude over the 0(1)90 degree quadrant, and swinging freely in azimuth on the short pillar mount. Sighting horizontally the scale reads 0°; vertically, 90°. Thus we have a straightforward astronomical quadrant measuring angular altitudes of celestial bodies as well as topographic features, buildings, etc. But a small scale, with index pointer, on the reverse tells a further story, and speaks of probable maritime use. Covering altitudes of less than 8°, this scale is divided from 500 yards to 2000 yards and beyond. The 500 yard mark corresponds to about 7.°25, which is the angular height of an object about 190 feet tall, at that distance. Few things on land have such a typical height but it is a reasonable estimate for the mast heights of the tallest sailing ships. For example, we find in 1830 the 1300 ton merchant ship had a main mast of 179 feet. Contained in a somewhat stained simple pine box, this unusual instrument is in very fine condition.