The time at which the attractive property of the magnet was discovered,
is by no means known; certain, however, it is, that mankind were
acquainted with it at a very early period. Father Kircher endeavours to
prove that the Jews were aware of the magnet's singular property of
attracting iron; and from Plutarch, it appears that the Egyptians were
not ignorant of it. Pythagoras, Ptolemy, and several other ancient
philosophers, knew and admired this wonderful property of the magnet.
Thales and Anaxagoras were so struck with it, as to imagine that the
magnet had a soul; and Plato said that the cause of its attraction was
divine. But the _directive_ property of the magnet was not known to the
ancients. To the simple application of this property, which was either
discovered or introduced into Europe about 500 years ago, mankind is
indebted principally for the discovery of a new continent nearly equal
to the old one, for an extensive commerce between the most distant
nations, and for an accurate knowledge of the shape and size of the
world we inhabit. The use of the magnetic needle was not known in Europe
before the thirteenth century. The honour of its discovery has been much
contested; but by the consent of most writers, it seems to belong to
Flavio Gioja of Amalfi. He lived in the reign of Charles of Anjou, who
died in 1309; and it was, it is said, in compliment to this Sovereign
that Gioja distinguished the North Pole by the emblem of France, the
_fleur-de-lis_. Du Halde, in his book upon China, indeed, intimates that
the use of the magnetic needle was known to the ancient Chinese.
Speaking of the Emperor Hoang-ti, when he gave battle to Tchi-Yeou, he
says: "He, perceiving that thick fogs saved the enemy from his pursuit,
and that the soldiers rambled out of the way and lost the course of the
wind, made a car which showed them the four cardinal points. By this
method he overtook Tchi-Yeou, made him prisoner, and put him to death.
Some say that there were engraven on this car, on a plate, the
characters of a rat and a horse, and underneath was placed a needle to
determine the four parts of the world. This would amount to the use of
the compass, or something near it, being of great antiquity and well
attested." In another place, speaking of certain ambassadors, Du Halde
says: "After they had their audience of leave, in order to return to
their own country, Tcheou-Kong gave them an instrument, which on one
side pointed towards the north, and on the opposite side towards the
south, to direct them better on the way home, than they had been
directed in coming to China. The instrument was called _Tchi-ran_, which
is the same name as the Chinese now call the sea-compass by; this has
given occasion to think that Tcheou-Kong was the inventor of the
compass." This happened in the twenty-second cycle, about 1040 years
before Christ; but, notwithstanding the assertions of Du Halde, strong
reasons have been adduced against the mariner's compass being known
among the ancient people of China and of Arabia. The French also have
laid claim to the discovery of the compass, and in the Imperial Library
at Paris there is a poem, contained in a curious quarto manuscript of
the thirteenth century, on vellum, in which the mariner's compass is
evidently mentioned; but still it appears that the Neapolitan, Flavio
Gioja, if not the original discoverer, was at least the first who used
the mariner's compass, or constructed it for the use of vessels in the
Mediterranean.
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