拍品 150
150
A brass and ebony octant, lacking makers bone plaque, with double 'pin hole' sight and slide, three shades, mirror and mirror mount, the brass index arm with framed vernier scale and clamp, the bone arc engraved with scale divided 0-105°, on three brass pillar feet - 12in. wide

細節
A brass and ebony octant, lacking makers bone plaque, with double 'pin hole' sight and slide, three shades, mirror and mirror mount, the brass index arm with framed vernier scale and clamp, the bone arc engraved with scale divided 0-105°, on three brass pillar feet - 12in. wide