56-hour marine chronometer
Date1855-1881
Inventory Number1998-1-1320
ClassificationChronometer
Subject
Maker
John Poole
fl. 1826 - 1881
User
Oak Ridge Station
1931 - 2005
User
George R. Agassiz Station, Harvard
1951 - 1982
User
Harvard College Observatory
founded 1839
Cultural Region
Place of Origin
Dimensionschronometer: 15.3 × 15.9 × 7 cm (6 × 6 1/4 × 2 3/4 in.)
case: 19.2 × 21.6 × 20 cm (7 9/16 × 8 1/2 × 7 7/8 in.)
case: 19.2 × 21.6 × 20 cm (7 9/16 × 8 1/2 × 7 7/8 in.)
Material
DescriptionChronometer in mahogany case, 56 hour duration, with instructions for care pasted on inside lid of case.
The chronometer is gimbal mounted inside a box with the traditional double lid of a chronometer case. The top lid is solid wood; the lower lid has glass on top. The gimbals have a brake and locking screw. The winding key is in the box. The box has a latch operated by a sliding button. The corners of the box are reinforced with brass. There are two brass handles on the sides of the box. Green felt is glued to the underside of the box (probably a later addition).
The chronometer's dial has hours marked I-XII with divisions every minute around the face. The upper circle inside the hour scale shows hours remaining until the clock will wind down, 0-54, graduated every 6 hours. It is marked "WIND," "DOWN," and "UP." The lower inner circle shows seconds 0-60.
The brass name plate of the box is blank. A hard rubber plate for the serial number is also left uninscribed.
The chronometer is gimbal mounted inside a box with the traditional double lid of a chronometer case. The top lid is solid wood; the lower lid has glass on top. The gimbals have a brake and locking screw. The winding key is in the box. The box has a latch operated by a sliding button. The corners of the box are reinforced with brass. There are two brass handles on the sides of the box. Green felt is glued to the underside of the box (probably a later addition).
The chronometer's dial has hours marked I-XII with divisions every minute around the face. The upper circle inside the hour scale shows hours remaining until the clock will wind down, 0-54, graduated every 6 hours. It is marked "WIND," "DOWN," and "UP." The lower inner circle shows seconds 0-60.
The brass name plate of the box is blank. A hard rubber plate for the serial number is also left uninscribed.
In Collection(s)
Signedon face: John Poole / MAKER TO THE ADMIRALTY / 57 Fenchurch St. London
Inscribedserial number on face: 2096
Curatorial Remarkstag: Frame maker/ Finisher G.H.
tag: Very dirty / oil oxidized / Do not run / unless overhauled.
FunctionA marine chronometer was used on a ship to keep the time from the port of origin or an established zeroth longitude (such as Greenwich, England) 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.
ProvenanceHarvard College Observatory; transferred from Agassiz Station to CHSI, 21 May 1969.
John Bliss & Company
Date: circa 1880
Accessories: "Tipsy" winding key
Object number: DW0246
Charles Frodsham
Date: circa 1865
Accessories: winding key.
Object number: 1998-1-1319
William Bond and Son
Date: circa 1860
Accessories: carrying case
Object number: 2005-1-0015a
Arnold & Dent
Date: 1830-1840
Accessories: winding (tipsy)
Object number: 1998-1-1321
Institute of Geographical Exploration
Date: circa 1900
Accessories: winding key; geared allen wrench; leather holster. Associated with printing chronograph.
Object number: DW0471a
Charles Frodsham & Company, Ltd
Date: circa 1900
Accessories: "Tipsy" winding key; (box key missing)
Object number: DW0360
Samuel Thaxter & Son
Date: 1825-1843
Object number: DW0519
E. S. Ritchie & Sons
Date: 1919
Accessories: azimuth circle (5330b)
Object number: 5330a
