THE MAGNETIC north-south pointing properties of the lodestone, or magnetite, may have been used for direction-finding in China 2,300 years ago - or perhaps, if old tales have any validity, 300 years...
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THE MAGNETIC north-south pointing properties of the lodestone, or magnetite, may have been used for direction-finding in China 2,300 years ago - or perhaps, if old tales have any validity, 300 years...