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Description: | The lodestone, a piece of magnetite, which is naturally magnetic, was vital in the early centuries of navigation to ensure that the ship's compass worked properly. Until the mid-18th century, when improved compasses were developed, compass needles lost their magnetism quite quickly and had to be re-magnetised by stroking a lodestone along the needle's length.
Lodestones were often mounted in frames of brass, bronze or silver, and sometimes had an iron or steel keeper - a bar to help preserve their magnetic power. This lodestone has a brass frame with a carrying loop on top, and is 'armed' with two pieces of steel at the bottom, which help to increase the magnetic strength of the lodestone. This is a particularly large lodestone, which weighs over 9Kg (20 lbs) and was probably used for scientific experiments rather than for navigation.
caption: Bronze Mounted Lodestone, 1690 | Publisher: | "http://collections.rmg.co.uk/" | Rights holder: | "Royal Museums Greenwich" | Subjects: | lodestones The Old Royal Observatory Greenwich Lodestone | Source: | Royal Museums Greenwich | Identifier: | http://collections.rmg.co.uk/collections... | Go to resource |
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Lodestone
Lodestone mounted in moulded brass…
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