Astronomical and navigational instruments, Compasses

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Mariner's compass

NAV0383
Astronomical and navigational instruments

Object connections:

Collection Astronomical and navigational instruments, Compasses
User collections William Wales by NMMCollections
Stories from the sea by rboley
Gallery locationNot on display

Object details:

Object ID NAV0383
Description The compass is housed in a wooden box, with a lid and an internal glass cover to allow the compass to be viewed while in the box. It is a dry card compass, marked with the points but not with degrees. The brass compass-housing fits onto a spike in the bottom of the box that allows the compass to move around and remain level. When not in use, a wooden slide within the box holds the compass in place. At the north point of the compass card is the inscription ‘G. Knight Invt.’. This refers to Dr Gowin Knight (1713–72), who in 1745 invented a method for making strongly magnetic steel bars, and from this developed a steel compass needle which retained its magnetism much longer than the needles used previously. This innovation did away with the need to continuously re-magnetize compass needles with a lodestone during a voyage, although compasses were taken to an instrument-making firm to re-magnetize the needles once they returned to port. The maker’s name appears both on the compass card and on the cover of the compass and refers to George Adams (1750–1795) of the Adams firm founded by his father. The firm was one of the leading instrument suppliers in London in the late 18th century, with clients including the Board of Ordnance as well as being appointed instrument makers to the king. George Adams was employed as the sole agent for Knight’s compasses.
Date made circa 1776

Artist/Maker Adams, George
Place made London, England
Credit National Maritime Museum, Greenwich, London
Materials brass; glass; steel; wax; wood; paper
Measurements Compass: 75 mm x 198 mm x 190 mm
Parts
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