56-hour marine chronometer
Date: circa 1860
Inventory Number: 2005-1-0015a
Classification: Chronometer
Subject:
Maker: William Bond and Son (fl. 1793 - 1977)
Cultural Region:
Place of Origin:
Dimensions:
18 x 16.5 x 16 cm (7 1/16 x 6 1/2 x 6 5/16 in.)
carrying case: 23 x 22 x 22.5 cm (9 1/16 x 8 11/16 x 8 7/8 in.)
Accessories: carrying case
Description:
The chronometer is inserted into a gimballed mahogany box. When the cover is opened, one can see the chronometer's dial through the glass. A second part can be opened to have access to the chronometer per se. This section can be locked by means of a key. When it is released from the clamping mechanism, the chronometer pivots on two axes to follow the movement of the ship.
Roman numerals in increments of fives are found on the large silvered dial. Arabic numerals (60-5-10- et seque) compose the seconds dial. Both the up-and-down and seconds dials have blued steel hands whereas the hour and minutes hands are gold plated.
This chronometer is probably based on an Earnshaw escapement, with a cut bimetallic balance, cylindrical heat compensation weights, and a polished steel helical balance spring all in a brass bowl. Wound up, this chronometer was good for two days.
Roman numerals in increments of fives are found on the large silvered dial. Arabic numerals (60-5-10- et seque) compose the seconds dial. Both the up-and-down and seconds dials have blued steel hands whereas the hour and minutes hands are gold plated.
This chronometer is probably based on an Earnshaw escapement, with a cut bimetallic balance, cylindrical heat compensation weights, and a polished steel helical balance spring all in a brass bowl. Wound up, this chronometer was good for two days.
In Collection(s)
Signedon dial: WM. BOND & SON, / BOSTON. Nº. 497.
Inscribedivory disc on front of the box: 2545
FunctionA marine chronometer was used in a ship to keep the time from the port of origin while at sea. With that data, ships were able to find the longitude anywhere on the ocean by simply determining the time at their current position.