backplate - from catalog card: 2 3/16 in; 5.588 cm
overall: 2 3/4 in x 4 1/4 in; 6.985 cm x 10.795 cm
Object Name:
box chronometer, without case
Other Terms:
box chronometer, without case; chronometer, marine; Mechanical, Spring-Driven
Place made:
United Kingdom: England, London
Date made:
1838-1843
1838 - 1843
Description:
This instrument is a specialized timekeeper designed for finding longitude at sea. Its form is that of the standardized 19th-century marine chronometer. It was transferred to the Smithsonian from the U.S. Navy’s Bureau of Ships. The chronometer’s finisher, the firm of Charles Frodsham, traded in high-quality chronometers, clocks and watches. Frodsham (1810-71), was the son of William James Frodsham, co-founder of Parkinson & Frodsham. The younger Frodsham’s firm underwent many name and address changes, but continued in business from roughly 1837 until it became a subsidiary of Devon Instruments in 1977.
Mechanism details:
Escapement: Earnshaw, spring detent
Duration: 56-hour
Power source: Spring drive with chain and fusee
Balance spring: helical, blued steel
Key missing
Bowl details:
Brass bowl, fitted with a sprung cylindrical inner bowl as a dust cover (original work)
Brass fittings for gimbal, gimbal missing
Bezel screwed and milled
Crystal flat, small unpolished chamfer
Dial details:
Engraved and silvered brass
Indicates hours, minutes, seconds, winding level up and down
