overall - box: 7 1/8 in x 7 in x 6 3/8 in; 18.0975 cm x 17.78 cm x 16.1925 cm
overall - key: 3 in x 1 1/4 in x 3/4 in; 7.62 cm x 3.175 cm x 1.905 cm
dial - from catalog card: 3 3/8 in; 8.5725 cm
box - from catalog card: 6 1/2 in x 6 1/2 in x 6 1/2 in; 16.51 cm x 16.51 cm x 16.51 cm
Object Name:
box chronometer
Place made:
United Kingdom: England, London
Date made:
ca 1840
Description:
This instrument is a specialized timekeeper designed for finding longitude at sea. Its form is that of the standardized 19th-century marine chronometer. Parkinson & Frodsham, a firm trading in high-quality chronometers, clocks and watches, was established in 1801 by William James Frodsham (1778-1850) and William Parkinson (d. about 1842). From 1801 to 1890, the firm’s business address was 4 Change Alley, and thereafter at other addresses until 1947.
Mechanism details:
Escapement: Earnshaw, spring detent
Duration: 56-hour
Power source: Spring drive with chain and fusee
Balance spring: Helical, blued steel, Earnshaw type
Inscription: "Parkinson & Frodsham." on backplate, "Change Alley / London" on barrel bridge
Bowl details:
Brass bowl
Brass gimbals
Bezel screwed and milled
Crystal convex and chamfered
Dial details:
Engraved and silvered brass
Indicates hours, minutes, seconds, winding level up and down