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Deck watch no. 98618 by E. M. T — view 1 of 2
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Instruments · Deck watch

Deck watch no. 98618 by E. M. T

DocumentedDocumented from the holding institution's catalogue record.
Maker / attribution
E. M. T. (maker)
Date
c. 1940
Historical period
Golden Age of Mechanical Watchmaking (1900 – 1945)
Country of origin
Unrecorded in source
Object type
Deck watch
Materials / technique
metal; wood; glass
Dimensions
Overall: 41 x 106 x 146 mm
Holding institution
Royal Museums Greenwich
Accession / object no.
ZBA7904
Credit line
National Maritime Museum, Greenwich, London
Catalogue title (original)
98618 (English)

View the source record ↗ (opens another website in a new tab)Suggest a correction

Record summary

Held and catalogued by Royal Museums Greenwich (object number ZBA7904), this is a deck watch by E. M. T., dated c. 1940. The Atlas places it in the Golden Age of Mechanical Watchmaking period (1900 – 1945) of its Instruments collection. Materials and techniques recorded by the source: metal; wood; glass. Recorded dimensions: Overall: 41 x 106 x 146 mm. 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

Catalogue description — Royal Museums Greenwich

A deck watch numbered 98618, by E. M. T. A jewelled movement with no markings except the regulator scale marked ‘A R’ and ‘F S’. There isa club-tooth lever escapement and two-arm compensation balance. The movement is housed in an open-face stainless-steel case with screw-on back and bezel with glass. The back is marked inside ‘SWISS / ACIER INOXYDABLE / 98618’, and outside the broad arrow with an applied sticky label handwritten ‘98618’. A pull-out, hand-setting winding crown is at the XII-position. A white enamel dial has Roman hour numerals with Arabic five-minute/second figures outside and centre-seconds. There are no inscriptions on the dial. The movement is housed in a mahogany deck box with a hinged lid opening 180°. The box has a flip-catch to lock it. The box lid is lined with green baize and includes a brass label-holder (empty). The watch sits in a circular green baize-lined aperture in the base of the box and can be seen through a circular porthole glass window when the lid is closed. The underside of the box is covered in green baize. E. M. T. was a Swiss maker of high-grade commercial lever-escapement pocket watches, which during and after the Second World War, were obtained by the UK Government and re-cased in stainless steel to meet demands. They were additionally housed in wooden deck watch boxes manufactured by the Admiralty chronometer workshops. In the 1950s and 1960s many were sent to Karachi for use by the Pakistan Navy, with others being dispersed to India, Egypt and the Republic of Ireland.

Historical context

Golden Age of Mechanical Watchmaking (1900 – 1945)

The wristwatch displaces the pocket watch; waterproof cases, self-winding and grand complications.

Timing instruments became electrical and specialised: industrial time recorders, sports timers and aviation instruments.

Read the period in the timelineMore instruments from this periodEarlier: Industrial Revolution

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.

Read next:Spring detent (chronometer) escapementFuseeBalance spring (hairspring)Detent escapement

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