56-hour marine chronometer
Date: circa 1865
Inventory Number: 1998-1-1319
Classification: Chronometer
Subject:
Maker: Charles Frodsham (1810-1871)
User: Harvard College Observatory (founded 1839)
Cultural Region:
Place of Origin:
Dimensions:
closed: 19.5 × 20 × 17.8 cm (7 11/16 × 7 7/8 × 7 in.)
Accessories: winding key.
Description:
This 56-hour chronometer has a matte silver dial. The outer ring is divided into minutes, and marked with Arabic numerals 5 - 60 every 5. The hours run I-XII. An inner ring at the bottom of the face is divided into seconds and marked every 10. An inner ring near the XII is marked in hours 0-56 showing how long the clock has been running. One side is marked "Down" and the other "Up." The hour and minute hands are bright brass; the second and winding hands are blued steel.
Chronometer is mounted in gimbals inside a mahogany box with two covers. The top cover is solid wood and has a brass plaque embedded in the center. A button opens this cover to reveal a glass cover through which one can read the clock. A key (missing) releases this cover to access the clock for winding.
The winding key is stored in the box. There is a brake for the gimbals. The box has brass handles on the sides. Two corners of the box have binding posts for electrical connections.
Chronometer is mounted in gimbals inside a mahogany box with two covers. The top cover is solid wood and has a brass plaque embedded in the center. A button opens this cover to reveal a glass cover through which one can read the clock. A key (missing) releases this cover to access the clock for winding.
The winding key is stored in the box. There is a brake for the gimbals. The box has brass handles on the sides. Two corners of the box have binding posts for electrical connections.
In Collection(s)
Signedon dial: CHARLES FRODSHAM, / 84 STRAND LONDON. / No. 3451.
on ivory label on case: CHAS. FRODSHAM, / 84 / Strand / LONDON. / No. 5451
on ivory label on case: CHAS. FRODSHAM, / 84 / Strand / LONDON. / No. 5451
Inscribedserial number on dial: No. 3451
serial number on box: No. 5451
serial number on box: No. 5451
FunctionA marine chronometer was used on a ship to keep the time at the place of zeroth longitude (typically Greenwich, England). With that data, navigators were able to find the longitude anywhere on the ocean by simply determining the time at their current position and comparing it with the chronometer's time.
Historical AttributesA tag on the instrument suggests that this instrument was used on a "Chronometric Expedition, 1855. Wm. Bond left Boston with a number of Chronometers June 6, 1855 12.17 PM aboard steamship America." However, this chronometer dates from about 1865 and could not have been among the instruments Bond took. It may still have an association to the Harvard College Observatory.
Curatorial RemarksInformation from Richard Stenning of Charles Frodsham and Co., London on 06/23/98: The Admiralty purchased Frodsham 3449 in 1867 and no. 3464 in 1870; he believes that No. 3451 would have been made about 1865.