Details
A fine 19th-Century ivory and electrum surveying combined folding rule/inclinometer and compass,
signed Dollond London, the hinge-pin engraved with rose, the upper arm with lever and twin folding sights, the lower arm with folding compass, the edge-bar needle on jewelled pivot and with bubble-level, both arms stamped with scale for horizontal distance angle of dip and dip depression and thickness, the hinge plates engraved with a scale for rise in inches per yard, the back-side measured with a folding one-foot rule and scale for angle of incline, each arm 6in. long
signed Dollond London, the hinge-pin engraved with rose, the upper arm with lever and twin folding sights, the lower arm with folding compass, the edge-bar needle on jewelled pivot and with bubble-level, both arms stamped with scale for horizontal distance angle of dip and dip depression and thickness, the hinge plates engraved with a scale for rise in inches per yard, the back-side measured with a folding one-foot rule and scale for angle of incline, each arm 6in. long