Spencer, Browning & Rust octant, c 1800
An spencer, browning & rust octant. Ca 1800. There is also an sign of sbr in the degree scale (-5 to +100 degrees). The 3 shade glass assembly is movable for placements at either the index mercury mirror position or below at the secondary position where the 3 mirror allows for taking a back sights. In original stair stept case is a retailer sign by charles c hutchinson boston.