Circular protractor

Circular protractor with beam compass, brass with silver (?) scales.
Protractor-Dia. 6.25" (16cm) graduated to 360 degs by 30'. A straight edge 10.1" (25.6cm) long, formed by the frame of the instrument, is carried at the centre.
Beam compass-Length 14.6" (37cm) with pins at each end, is mounted on frame with two index arms with vernier scales and attached at centre of instrument.
Vernier scales-#two scales graduated 15-0-15 to 2' of arc are attached to ends of index arms. One of the arms carries a tangent screw and clamp.

Object Details

ID: NAV0584
Type: Circular protractor
Display location: Not on display
Creator: Jones, Thomas, & Sons
Date made: circa 1800
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 40 mm x 372 mm x 175 mm