Crafted from mahogany and boxwood with bone and brass, Signed Alex'r Martin, 1775. This quadrant's height of 19 1/2 inches puts it amongst the largest we have had. A large size would have been more costly, but easier to use as it allows the index arc to be engraved and read with more accuracy. This instrument has a 90 degree arc on the index with +/- five degrees on either side. In very good condition for an instrument of this age, part of the scale has been replaced at some point during its useful life.
