Instruments · Marine chronometer
Marine chronometer by Delolme, London, c. 1860
- Maker / attribution
- Delolme (maker)
- Date
- c. 1860
- Historical period
- Industrial Revolution (1850 – 1900)
- Country of origin
- England
- Place
- London
- Object type
- Marine chronometer
- Dimensions
- Height 17.5 cm
- Stock no.
- SKU 108
- Credit line
- Dealer listing, Howard Walwyn (SKU 108)
- Catalogue title (original)
- DELOLME N° 667. A good small 2-day marine chronometer (English)
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Record summary
Catalogued by Howard Walwyn Fine Antique Clocks (dealer), London (stock number SKU 108), this is a marine chronometer by Delolme, made in London, England, dated c. 1860. The Atlas places it in the Industrial Revolution period (1850 – 1900) of its Instruments collection. Recorded dimensions: Height 17.5 cm. The record is illustrated with 2 photographs.
Assembled from the source record's structured fields. Dates and attributions are given as the source states them; where a field is missing the Atlas leaves it blank rather than estimating.
Catalogue description
Dealer description — Howard Walwyn
A good small 2-day marine chronometer in its original mahogany wooden box, the 56-hour movement with its original dovetail type spring detent escapement, blued steel helical spring and bimetallic balance with circular timing weights. It comes with its original turned brass tipsy winding key. The 3 ½ inch silvered brass dial has Roman hour numerals and an outer double minute band. There is a subsidiary dial for up/down below XII and a subsidiary seconds above VI. The maker’s signature and address are inscribed across the middle between IX and III. The nicely faded plain mahogany case has three tiers with two lifting lids. It is numbered 667 on an ivory plaque as per the number on the dial of the movement. To each side of the case is an inset brass carrying handle. Date : circa 1860 Height : 7 in (17.5 cm) Width : 6 ¾ in (17 cm) Depth : 6 ¾ in (17 cm) * Henry Delolme is listed on page 128 of Tony Mercer’s Revised Edition of Chronometer Makers of the World , 2004 as working in Rathbone Place off Oxford Street, London between 1856 and 1872. He apparently went bankrupt and died in 1899. Signed / Inscribed Delolme London. N° 667. HW5714
Historical context
Industrial Revolution (1850 – 1900)
American interchangeable-parts manufacture; railroad time standards; Swiss and German factory systems.
Instruments spread into industry, science and sport: stopwatches, chronoscopes, metronomes, watchmen's clocks and time recorders.
Read the period in the timelineMore instruments from this periodEarlier: Precision & Scientific Horology
Atlas type guide
Marine chronometers
A marine chronometer is a precision timekeeper carried at sea to find longitude: the navigator compares local noon, observed with a sextant, with the time at a reference meridian kept by the chronometer. Each hour of difference corresponds to fifteen degrees of longitude. John Harrison proved the method in the 1760s; Pierre Le Roy, Ferdinand Berthoud, John Arnold and Thomas Earnshaw then developed the detent escapement and the compensation balance that made chronometers practical to manufacture.
By the nineteenth century London, Liverpool, Le Locle and Glashütte supplied navies and merchant fleets. A typical box chronometer has a spring-detent escapement, a fusee to equalise mainspring torque, a bimetallic compensation balance with a helical balance spring, and is mounted in gimbals inside a wooden box so that it stays level.
What to look for
- Gimbals and a three-tier wooden box with a glazed inner lid.
- A power-reserve ('up and down') indicator on the dial, usually showing 56 hours on two-day instruments.
- Spring-detent escapement and a cylindrical (helical) balance spring visible through the movement.
- Admiralty or navy marks (broad arrow), and rating certificates from observatories.
- The maker's number on the dial and movement; many makers' registers survive, allowing dating.
Dating clues
- Earnshaw-type spring-detent chronometers became standard after about 1800.
- Auxiliary compensation devices on the balance appear from the mid-nineteenth century.
- Quartz and radio time signals ended routine use of mechanical chronometers in the 1970s and 1980s.
General guidance written by the Atlas editors about this kind of object. It is not a statement about this particular piece; for that, rely on the source record above and on physical examination.
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