The attractive power of the loadstone has been known from a very
remote period. The natural magnet appears native in a gray iron ore
in octahedral crystals, composed of 168 parts of iron, and 64 parts
of oxygen. Its properties seem to have been studied in Europe during
the dark ages and a directive power is alluded to by Cardinal James de
Vitri, who flourished about the year 1200, who observed that it was
indispensable to those who travel much by sea.
In modern times, the history as well as the nature of the magnet has
engaged remarkable attention; and it has been determined beyond all
dispute that the magnet was used by the Chinese under the name of
the _tche-chy_ (directing stone) about 2604 years before Christ. It
passed from them to the Arabs, and was first used in Europe after the
crusades; and Ludi Vestomanus asserts that about the year 1500 he saw
a pilot in the East Indies direct his course by a magnetic needle like
those now in use.