About this site

Terrestrial globe clock. Terrestrial globe clock. Geographical details on the sphere include oceans filled-in by a wave pattern. Asia and America are part of one continent, and South America is labelled. There is a hypothetical southern continent around t
1552
National Maritime Museum

Year-Going Clock. Year-going clock by Thomas Tompion, 1676 This is one of two clocks especially commissioned by Sir Jonas Moore, Master of Ordnance and patron to the first Astronomer Royal, John Flamsteed, for use at the Royal Observatory from its openin
1676
National Maritime Museum

Sidereal degree clock. This clock was designed by John Flamsteed, first Astronomer Royal, to show the time in degrees, minutes and seconds of arc. In astronomy it is often more convenient to express time in this way. The earth turns through 360°on its
1691
National Maritime Museum

. Hood for the solar sidereal long-case clock.
1716
National Maritime Museum

. Solar sidereal long-case clock, purchased in 1716 by the Royal Hospital for Seamen at Greenwich for its Council Room, though only paid for (£70) in 1718 owing to initial dissatisfaction with its performance. One of only three of its kind known to
1716
National Maritime Museum

. Trunk for the solar sidereal long-case clock.
1716
National Maritime Museum

Description abregee d'une horlorge d'une nouvelle invention.... Book accompanying ZBA2248: "Description abreges d'une hortage d'une nouvelle invention...".
1724
National Maritime Museum

Experimental marine chronometer, Sully "C". Door of the Sully marine chronometer case
1724
National Maritime Museum

Experimental marine chronometer. Experimental marine timekeeper: Inscription. Comes with book "Description abreges d'une hortage d'une nouvelle invention...", see ZBA2248.2.
1724
National Maritime Museum

Screws. Screws which were used to attach the object to CASE 0632 when it was on display in ROG; FHB; 744.
1724
National Maritime Museum

. This unusual stop watch records short intervals of time to tenths of seconds and it belonged to the 5th Astronomer Royal, Nevil Maskelyne. We know from his memoranda that Maskelyne received the watch from its maker, William Coombe, July 17th, 1786. Very
1786
National Maritime Museum

309. A pair cased pocket chronometer by Thomas Earnshaw that belonged to the fifth Astronomer Royal, Nevil Maskelyne.

National Maritime Museum

572. Quarter-repeating pocket watch in a gold / silver-gilt pair case. It has a full-plate capped fusee movement, signed and numbered, with a cylinder escapement and plain balance. The watch has a white enamel dial with Roman numerals and pierced hands; h
circa 1727
National Maritime Museum

. Black plastic ‘Accurist’ wrist-watch case containing four pieces of the original H1 gridiron, two brass and two steel. The box also contains a small glass phial with brass particles taken from H1 for analysis in the 1960s. These parts were r
1735
National Maritime Museum

. Lead filled brass counterweight, made and fitted to H1, almost certainly in the autumn of 1932 to replace a missing one. This was then cut off, with part of Harrison’s original counterweight arm, during either the 1952 or the 1961 restorations car
1735
National Maritime Museum

H1. Marine timekeeper, H1. This is the first experimental marine timekeeper made by John Harrison in Barrow-on-Humber between 1730 and 1735 as a first step towards solving the longitude problem and winning the great £20,000 prize offered by the Brit
1735
National Maritime Museum

. Brass crank winding key made for H2 in 1924 as part of Gould’s restoration. The key is engraved: 'HARRISON No.2 1924'.

National Maritime Museum

H2. Marine timekeeper, H2. Made between 1737 and 1739, this is a larger and more solidly built version of H1, see ZAA0034, with the additional refinement of a remontoire - a device to ensure that the drive to the two balances is as uniform as possible. It
1739
National Maritime Museum

. Broken suspension spring and three other metal components (in plastic bag) removed from ZBA2212.

National Maritime Museum

Gridiron pendulum. Box for the Gridiron pendulum.
1744
National Maritime Museum

Gridiron pendulum. Gridiron pendulum in a box. Removed from ZBA2212.
1744
National Maritime Museum

Gridiron pendulum. Lid for the Gridiron pendulum.
1744
National Maritime Museum

Part of John Harrison's third timekeeper (H3). An original manuscript drawing by Harrison of parts of H3 during its evolution, probably in the late 1740s. The drawing shows the rear of the clock with the detail of the special isochronising device wit
1745
National Maritime Museum

Drawing of a turret clock escapement. Harrison’s own manuscript drawing of his design for the escapement of the turret clock at Trinity College, Cambridge, for which he was paid three guineas in 1755. The escapement itself was then made by the Londo
about 1755
National Maritime Museum

. Brass crank winding key made for H3 in 1931 as part of Gould’s restoration. The key is engraved: 'HARRISON No.3 1931'.
1757
National Maritime Museum

. Four brass support pillars, made in 1930 when H3 was being fitted into its first showcase, and transferred to the new showcase for the NMM display in 1936. All three large timekeepers remained in these 1936 showcases until 1984 when they were transferre

National Maritime Museum

. The front cap of H3’s caged roller bearing, removed for many years to enable the bearing to be observed on display.
1757
National Maritime Museum

. The glazed brass case of H3. The case is constructed from thin brass sheets, all pieces are carefully fabricated using coppersmiths dovetailed joints down the edges and silver-soldered, a highly skilled exercise on a piece as large as this. The thin gla

National Maritime Museum

. The rear cap of H3’s caged roller bearing removed for display. In the poor conditions at sea it was important to protect this very sensitive part from the ingress of dirt and dust and Harrison designed it to be virtually sealed with these caps.
1757
National Maritime Museum

Grasshopper pallet. Glass tube containing one of H3’s original oak pallets. The pallet nib end is missing and the pallet now has an experimental metal (zinc?) nib, made by Gould, clamped to it, as well as a small lead counterweight bound to the pall
1757
National Maritime Museum

H3. Marine timekeeper, H3. Started in 1740, this third timekeeper took Harrison nearly 19 years to build and adjust, although it was not to win him the great longitude prize: he found that he just could not persuade the two large, heavy, circular balances
1757
National Maritime Museum

H4. Marine timekeeper, H4. This is Harrison's prize-winning longitude watch, completed in 1759. Harrison had been working on improving watches as a sideline to his development of the much larger H3. In 1753 a pocket watch was made to Harrison's
1759
National Maritime Museum

. Watch crank key.
1764
National Maritime Museum

K1. A one day marine timekeeper with a 102mm diameter white enamel dial, in imitation of that of H4, with scrolling decoration at the quarters and roman hour numerals and Arabic ten-minute figures. It has polished and blued steel beetle and poker hands wi
1769
National Maritime Museum

. Key
1771
National Maritime Museum

. Regulation Key
1771
National Maritime Museum

. Various small brass pins removed from timekeeper in 1984
1771
National Maritime Museum

K2. A 102mm diameter plain white enamel ‘regulator’ type dial, with the main dial indicating minutes with Arabic five minute figures and signed ‘LARCUM KENDALL / LONDON’ below 60. There are subsidiary dials for hours, with roman ho
1771
National Maritime Museum

K3. A one day marine timekeeper with a 102mm diameter bronze dial plate, with three white enamel subsidiary dials, with the upper dial indicating hours in roman hour numerals. In the lower left is a dial indicating minutes with Arabic five minute figures
1774
National Maritime Museum

The Late Regulator. This regulator is known as the ‘RAS’ (Royal Astronomical Society) or ‘Late’ regulator, to distinguish it from the earlier wooden precision pendulum clocks made by Harrison in the 1720s. It was his last word in f
1775-6
National Maritime Museum

36. Pocket chronometer with 22ct gold case, by John Arnold of London. Case hallmarked for London 1778, numbered 1/36.
1778
National Maritime Museum

2517. Pocket watch in a hallmarked silver pair-case. It has a full-plate fusee movement, with a verge escapement and plain balance. The watch has a white enamel dial with Roman numerals and spade and poker hands (most of minute hand is broken off and miss
circa 1780
National Maritime Museum

Astronomical chronometer. Astronomical chronometer. Thomas Earnshaw made this watch for George Margetts to Margett's design of complex astronomical dialling, but incorporating Earnshaw's spring detent escapement invention. These early chronomete
1783
National Maritime Museum

. Short interval timer winding key?
1786
National Maritime Museum

412. Pocket chronometer in a silver-gilt case, within a wooden deck box.
1789
National Maritime Museum

. John Hind, London c.1793 2 day marine chronometer in mahogany box Hind…. Box/Mounting Box adapted from a small, three tier mahogany chronometer box of about 1830, the whole now measuring 121mm high, 164mm wide, and 157mm deep. The box re
1793
National Maritime Museum

. Three steel screws associated with ZAA0007 Marine chronometer.
1793
National Maritime Museum

. Key for portable time keeper.
1795
National Maritime Museum

. Piece of broken glass contained in a plastic bag associated with ZAA0010 portable time keeper.

National Maritime Museum

. Steel and brass winding key associated with ZAA0731 Marine chronometer.
1795
National Maritime Museum

8. Marine timekeeper in glazed case within an octagonal wooden box
1795
National Maritime Museum

Portable time keeper. Portable time keeper. A piece of glass marked ZAA0010.1 and the key marked ZAA0010.2 can be viewed via the Whole/Part toggle.
1795
National Maritime Museum

. Brass bush removed from marine chronometer, contained in a plastic bag. This item has been replaced back into the chronometer.

National Maritime Museum

. Marine chronometer box with gimbal, bowl, bezel and winding key contained in a plastic bag.
1796
National Maritime Museum

12. The gilt-brass dial plate has two enamel plates attached for hours/minutes and seconds, flanked by highly chased and engraved solid silver spandrel decorations. The timekeeper has polished blued steel beetle and poker hands with a fine pointer blued s
1796
National Maritime Museum

427. Marine chronometer movement now mounted vertically in a box with carrying handle. Made in 1796, this chronometer, serial number 427, was used in the Royal Navy until 1830. It was subsequently transferred from the Admiralty to the Royal Observatory Gr
1796
National Maritime Museum

No.10, one day variant ‘Mudge copy’ type marine timekeeper.. The single, enamel dial plate has a separate circle for hours/minutes in the upper part and seconds in the lower, signed in between: ‘No.10 - (+symbol of anchor)’ and &ls
1796
National Maritime Museum

No.16, two day ‘Mudge copy’ type marine timekeeper.. A two day marine timekeeper with a gilt-brass dial plate that has an eight day type dial with three enamel plates attached for hours, minutes and seconds. This is flanked by a highly chased
1796
National Maritime Museum

326. Arnold and Son, London c.1788/1810 No.326 Small 1 day marine chronometer in mahogany box For notes on Arnold and Son, see pp.xxx Box/Mounting Three-tier mahogany box measuring 95mm high, 93mm wide, and 92mm deep. The lid has ebony stringing to
about 1788/1810
National Maritime Museum

. Three steel screws and a pin associated with ZAA0003 watch in silver pair case.
1800
National Maritime Museum

. Wooden mantle clock case with a gilt metal dial mask.

National Maritime Museum

Model of Earnshaw's escapement. In order to satisfy themselves as to the actual function of the spring detent escapement for marine timekeepers, in March 1804 the Board of Longitude ordered rival Thomas Earnshaw and John Roger Arnold each to make a s
1804
National Maritime Museum

Pocket watch. Pocket watch in a hallmarked silver pair-case. It has a full plate fusee movement, signed and dated, with a double-wheel 'Ormskirk' escapement and plain balance. The watch has a white enamel dial with Roman numerals and spade and p
1806
National Maritime Museum

. Adjustable crutch from astronomical regulator ZAA0591.
1809
National Maritime Museum

. Brass weight pulley contained in plastic bag.

National Maritime Museum

. Iron mounting stud associated with ZAA0591 regulator.
1809
National Maritime Museum

. Pendulum from astronomical regulator ZAA0591.
1809
National Maritime Museum

. Suspension from astronomical regulator ZAA0591.
1809
National Maritime Museum

. Weight from astronomical regulator ZAA0591.
1809
National Maritime Museum

. Winding key from astronomical regulator ZAA0591.
1809
National Maritime Museum

An eight-day sidereal regulator, mounted within a stone block at the southern end of the Airy transit circle by William Hardy, London, circa 1811. An eight-day sidereal regulator, mounted within a stone block at the southern end of the Airy transit circle
circa 1811
National Maritime Museum

. Crank winding key from long case clock.
1810
National Maritime Museum

. Remains of post removed from clock
1810
National Maritime Museum

. Various components including a collet removed from clock
1810
National Maritime Museum

. Watch in an 18 carat gold open face case.
1810
National Maritime Museum

8960. Pocket watch in a hallmarked silver pair-case. It has a full-plate capped fusee movement, signed and numbered, with a rack-lever escapement and plain balance. The watch has a white enamel dial with Roman numerals and spade and poker hands.
circa 1810
National Maritime Museum

379. John Roger Arnold, London c.1811 No.379 1 day marine chronometer in mahogany box For notes on John Roger Arnold, see pp.xxx Box/Mounting Three-tier mahogany box measuring 125mm high, 135mm wide, and 122mm deep. The lid has ebony stringing to t
1811
National Maritime Museum

Pocket watch. Pocket watch in a hallmarked silver pair case. It has a full-plate capped fusee movement, marked 'Improved Patent', with a five tooth lever escapement as patented by Sam.Smith, Coventry (patent 3620, 9th December, 1812) and a secon
circa 1815
National Maritime Museum

Pocket chronometer. Pocket chronometer in a hallmarked silver consular case. It has a full-plate fusee movement, unsigned and unnumbered, with a spring detent escapement and compensation balance with helical balance spring. The watch has a white enamel di
circa 1817
National Maritime Museum

2358. Pocket watch in a hallmarked silver double-bottom open-face case. It has a full-plate capped fusee movement, signed and numbered, with a crank roller lever escapement and plain balance. The watch has a white enamel dial with Roman numerals and Arnol
1821
National Maritime Museum

5259. Pocket watch in a hallmarked silver pair-case. It has a full-plate capped fusee movement, signed and numbered, with the balance cock engraved 'DETACHED', with a lever escapement and plain balance. The watch has a white enamel dial with Rom
circa 1821
National Maritime Museum

8409. Pocket watch in a hallmarked silver full-hunter case. It has a full-plate capped fusee movement, signed and numbered, with a duplex escapement and flat-rim plain balance. The watch has a white enamel dial with Roman numerals, subsidiary seconds dial
circa 1821
National Maritime Museum

1379. Pocket watch in a hallmarked silver pair-case. It has a full-plate capped fusee movement, signed and numbered, with a crank roller lever escapement and plain balance. The watch has a white enamel dial with Roman numerals, subsidiary seconds dial, an
circa 1825
National Maritime Museum

569. John Roger Arnold, London c.1818 No.569 1 day marine chronometer in mahogany box For notes on John Roger Arnold, see pp.xxx Box/Mounting Three-tier brass bound mahogany box measuring 140mm high, 152mm wide, and 143mm deep. The lid has brass b
ca 1825
National Maritime Museum

1079. Pocket chronometer movement with dial and hands. It has a three-quarter plate fusee movement signed and numbered, with a spring-detent escapement (the detent is missing) and compensation balance with free-sprung helical balance spring. The watch has
1829
National Maritime Museum

Time ball. The red Time Ball, positioned on top of Flamsteed House is one of the world's earliest public time signals, distributing time to ships on the Thames and many Londoners. It was first used in 1833 and still operates today. The Time Ball wa
1833
National Maritime Museum

3483. Pocket watch in a hallmarked silver double-bottom open-face case with the glass missing. It has a full-plate capped fusee movement, signed and numbered, with an English lever escapement and plain balance. The watch has a cream enamel dial with Roman
circa 1839
National Maritime Museum

124. Marine chronometer
1848-9
National Maritime Museum

1853. The dial has roman hour numerals and the seconds dial has Arabic ten-second figures with straight batons at alternate five second intervals. The dial is signed across the centre: ‘John Poole / MAKER TO THE ADMIRALTY, / London No.1853’. T
1848-9
National Maritime Museum

462. A marine chronometer numbered 462, by McLachlan. It has an eight-day double-frame fusee movement with three pillars, all fixed with blued screws. The movement is marked with the broad arrow. The fusee, with stop-work and Harrison's maintaining p
1850
National Maritime Museum

. A bolt, 2 screws, 2 washers and 3 cylindrical components contained in a plastic bag, associated with ZAA0533 Shepherds clock.
1852
National Maritime Museum

. Four steel screws with washers (contained in a plastic bag) associated with ZAA0533 Shepherd's clock.
1852
National Maritime Museum

. Remains of various screws and a brass plate (contained in a plastic bag) from the bezel associated with ZAA0533 Shepherd's clock.
1852
National Maritime Museum

. Retaining bracket from the bezel and one screw (contained in a plastic bag) associated with ZAA0533 Shepherds clock.
1852
National Maritime Museum

. Seconds hand (contained in a plastic bag) from ZAA0533 Shepherd gate dial.
1852
National Maritime Museum

. Steel/iron nut contained in a plastic bag associated with ZAA00533.

National Maritime Museum

. Threaded brass disc (contained in a plastic bag) associated with ZAA0533 slave clock and dial.
1852
National Maritime Museum

. Various paint and putty samples and the remains of screws (contained in a plastic bag) associated with ZAA0533 slave clock and dial.
1852
National Maritime Museum

Slave clock and dial. Slave clock connected to the Shepherd master clock installed at the Royal Observatory in 1852. This slave clock was installed at the gates to the Observatory and was the first clock ever to show Greenwich Mean Time (GMT) directly to
1852
National Maritime Museum

Fallen time ball in the courtyard of the Royal Observatory, Greenwich. This watercolour by Hubert Airy, son of the Astronomer Royal George Airy, shows the Royal Observatory's time ball in the courtyard, having fallen from the roof of Flamsteed House.
Dec 1855
National Maritime Museum