LODESTONE

'Lodestone' or 'loadstone' refers to either:

★ Magnetite, a magnetic mineral form of iron(II), iron(III) oxide Fe₃O₄, one of several iron oxides.

★ A piece of intensely magnetic magnetite that was used as an early form of magnetic compass.
Iron, steel and ordinary magnetite are attracted to a magnetic field, including the Earth's magnetic field. Only magnetite with a particular crystalline structure, lodestone, can act as a natural magnet and attract and magnetize iron. The name "magnet" comes from lodestones found in a place called Magnesia.
In China, the earliest literary reference to magnetism lies in a 4th century BC book called ''Book of the Devil Valley Master'' (鬼谷子): "The lodestone makes iron come or it attracts it."Li Shu-hua, “Origine de la Boussole 11. Aimant et Boussole,” ''Isis'', Vol. 45, No. 2. (Jul., 1954), p.175 The earliest mention of the attraction of a needle appears in a work composed between 20 and 100 AD (''Louen-heng''): "A lodestone attracts a needle." By the 12th century the Chinese were known to use the lodestone compass for navigation.

Contents

References

See also

External links

References

See also

★ Magnetism

External links

★ Lodestone