Gold straight line lever escapement watch by Josiah Emery, London. Gold case, stamped VW (for casemaker Valentine Walker) and hallmarked 1792 – 3. White enamel dial with blued steel central minute hand and subsidiary dials for hours and seconds. Signed Emery London. Full-plate gilt movement with balance bridge. Straight line lever escapement, without draw. The balance staff has a cranked roller for impulse and unlocking and there is a separate safety roller. Brass balance with timing screws and two S-shaped bi-metallic arms. Helical balance spring. The pallets of the lever embrace five teeth of the escape-wheel. Signed ‘Josiah Emery, Charing Cross, London 1289’. Dust cap, also signed 'Josiah Emery Charing Cross London 1289'.

This watch is one of the first in which Emery used a cranked roller after abandoning his earlier, Mudge-type escapement on two planes

Clockmakers' Museum No. 455.