The Collections

The Board of Longitude

Created: 16.09.13

These are all objects connected in some way with the Board of Longitude, the name generally given to the group of Commissioners established by the 1714 Longitude Act to assess and reward ideas for solving the problem of finding longitude at sea. By the late eighteenth century, the Board was also judging a much broader range of projects relating to navigation more generally. There are three groups of instruments here. The first is of instruments submitted to the Board in the hope of gaining a reward under the terms of the various Longitude Acts and includes timekeepers, compasses and instruments for navigation by dead reckoning. The second comprises items such as timekeepers that were commissioned or purchased by the Board. The third includes instruments used on expeditions that the Board supported.

  • Name
  • Artist / Maker
  • Date made
  • ID
  • Jennings and Company
    circa 1818
    Jennings Insulating Compass

    A magnetic dry-card compass of a type patented by Henry Jennings in 1818 (no. 4259). The compass bowl is made of brass. The card is mica covered with paper, and is marked in points, with a fleur-de-lys at north. The…

  • Walker, Ralph
    circa 1793
    Azimuth compass

    Azimuth compass, consisting of a magnetic compass in a brass bowl, hung in gimbals that are weighted at the bottom with lead. The compass card (diameter 6.5 inches) is made of paper and is graduated to 32 points and quadrantally…

  • Unknown
    circa 1830
    Sounding Machine

    Sounding machines are used to determine the depth of water below a ship. This early 19th-century model is made of brass. It has a rotor which drives a pair of counters (one on each face) as it is dropped through…

  • Nairne, Edward
    Dip circle

    Dip circle or dipping needle, made of brass with gold pivots encased in copper. The needle is 12 inches (30.5 cm) long, and the circular scale is graduated quadrantally to 30 minutes. A dip circle measures the vertical component of…

  • Unknown
    circa 1830
    Mechanical log

    This instrument is designed to measure the distance covered by a ship. In this design, a brass rotor trails in the water and spins around as the boat moves along. This rotary motion is then passed through a register. Three…

  • Unknown
    Higginson's Log

    This is one of a number of instruments to measure a ship’s speed through the water. In this design, the log uses a spring balance held with the outer tube to record the pull of a rope attached to a…

  • Gilbert & Sons
    circa 1817
    Log glass

    The log glass was used in conjunction with a log and line to time the period during which a log line was allowed to unroll from the log reel and so estimate the ship's speed from the amount of line…

  • Bird, John
    circa 1758

    The sextant has a polished brass frame and limb, with a four-legged brass section on the back for the belt pole mounting. The detachable belt pole is made of brass and wood. The tangent screw and clamping screw, which are…

  • Hinde, John
    circa 1805
    Hoppe's Improved Sextant

    The sextant has a polished brass diamond-pattern frame with two polished limbs, two index arms, and a wooden handle. The tangent screws and clamping screws are positioned on the back of both index arms. The sextant has four shades, three…

  • Ramsden, Jesse
    circa 1772

    The sextant has a polished brass frame and limb with a wooden handle. The tangent screw, with its knob missing, is located on the front of index arm and the clamping screw is on the back. The lower part of…

  • Harrison, John

    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 British Government.…

  • Harrison, John

    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 design…

  • Harrison, John

    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,…

  • Harrison, John

    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…

  • Kendall, Larcum

    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…

  • Kendall, Larcum

    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…

  • Kendall, Larcum

    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 hour numerals, and for…

  • Breguet

    Breguet et Fils, Paris, c.1821 No.3194 2 day marine chronometer in mahogany box For biographical details of the firm of Breguet of Paris, see Box/Mounting Two-tier, plain mahogany box measuring 175mm high, 225mm wide, and 192mm deep. The top…

  • Barraud and Lund
    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 ‘BARRAUD – CORNHILL’. The dial would originally also have been signed…

  • Shelton, John
    circa 1769
    Astronomical regulator

    A one-month duration mahogany longcase regulator by John Shelton, London, circa 1769. The movement is of typical Graham/Shelton form with chamfered corners to the tall plates which are united by six latched knopped pillars. The five wheel train is driven…