{"product_id":"lodestone-f4767-002","title":"Lodestone","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.\u003cbr\u003e\u003cbr\u003eLodestones 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.","brand":"prodigi","offers":[{"title":"Fine art poster \/ XS: 20 x 15cm \/ none","offer_id":57028254859646,"sku":"GLOBAL-FAP-6X8","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ S: 40 x 30cm \/ none","offer_id":1848436555820,"sku":"GLOBAL-FAP-12X16","price":28.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ M: 60 x 45cm \/ none","offer_id":57028254892414,"sku":"GLOBAL-FAP-18X24","price":38.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ L: 80 x 60cm \/ none","offer_id":57028254925182,"sku":"GLOBAL-FAP-24X32","price":54.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ XL: 100 x 75cm \/ none","offer_id":57028254957950,"sku":"GLOBAL-FAP-30X40","price":69.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ S: 36 x 28cm \/ none","offer_id":57028254990718,"sku":"MUS-CFPM-11X14","price":59.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ M: 50 x 40cm \/ none","offer_id":1848436817964,"sku":"MUS-CFPM-16X20","price":79.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ L: 80 x 60cm \/ none","offer_id":57028255023486,"sku":"MUS-CFPM-24X32","price":119.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ XL: 100 x 75cm \/ none","offer_id":57028255056254,"sku":"MUS-CFPM-30X40","price":159.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ Single","offer_id":57028255089022,"sku":"GLOBAL-POST-MOH-6X4","price":1.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ 10-pack","offer_id":57028255121790,"sku":"GLOBAL-POST-MOH-6X4-10","price":14.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ 20-pack","offer_id":57028255154558,"sku":"GLOBAL-POST-MOH-6X4-20","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ Single","offer_id":57028255187326,"sku":"GLOBAL-POST-MOH-7X5","price":2.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ 10-pack","offer_id":57028255220094,"sku":"GLOBAL-POST-MOH-7X5-10","price":19.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ 20-pack","offer_id":57028255252862,"sku":"GLOBAL-POST-MOH-7X5-20","price":29.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ Single","offer_id":57028255285630,"sku":"GLOBAL-GRE-MOH-6X4-BLA","price":2.5,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ 10-pack","offer_id":57028255318398,"sku":"GLOBAL-GRE-MOH-6X4-BLA-10","price":15.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ 20-pack","offer_id":57028255351166,"sku":"GLOBAL-GRE-MOH-6X4-BLA-20","price":26.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ Single","offer_id":57028255383934,"sku":"GLOBAL-GRE-MOH-7X5-BLA","price":3.5,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ 10-pack","offer_id":57028255416702,"sku":"GLOBAL-GRE-MOH-7X5-BLA-10","price":19.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ 20-pack","offer_id":57028255449470,"sku":"GLOBAL-GRE-MOH-7X5-BLA-20","price":33.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/2785\/2654\/files\/f4767-002.jpg?v=1772717962","url":"https:\/\/prints.rmg.co.uk\/products\/lodestone-f4767-002","provider":"Royal Museums Greenwich prints","version":"1.0","type":"link"}