Over two thousand years ago, in far-away Asia Minor, a shepherd guarding
his flocks on the slope of Mount Ida suddenly found the iron-shod end of
his staff adhering to a stone. Upon looking further around about him he
found many other pieces of this peculiar hard black mineral, the smaller
bits of which tended to cling to the nails and studs in the soles of his
sandals.
This mineral, which was an ore of iron, consisting of iron and oxygen,
was found in a district known as Magnesia, and in this way soon became
widely known as the "Magnesstone," or magnet.
This is the story of the discovery of the magnet. It exists in legends
in various forms. As more masses of this magnetic ore were discovered in
various parts of the world, the stories of its attractive power became
greatly exaggerated, especially during the Middle Ages. In fact,
magnetic mountains which would pull the iron nails out of ships, or,
later, move the compass needle far astray, did not lose their place
among the terrors of the sea until nearly the eighteenth century.
For many hundreds of years the magnet-stone was of little use to mankind
save as a curiosity which possessed the power of attracting small pieces
of iron and steel and other magnets like itself. Then some one, no one
knows who, discovered that if a magnet-stone were hung by a thread in a
suitable manner it would always tend to point North and South; and so
the "Magnes-stone" became also called the "lodestone," or
"leading-stone."
These simple bits of lodestone suspended by a thread were the
forerunners of the modern compass and were of great value to the ancient
navigators, for they enabled them to steer ships in cloudy weather when
the sun was obscured and on nights when the pole-star could not be seen.
The first real _compasses_ were called _gnomons_, and consisted of a
steel needle which had been rubbed upon a lodestone until it acquired
its magnetic properties. Then it was thrust through a reed or short
piece of wood which supported it on the surface of a vessel of water. If
the needle was left in this receptacle, naturally it would move against
the side and not point a true position. Therefore it was given a
circular movement in the water, and as soon as it came to rest, the
point on the horizon which the north end designated was carefully noted
and the ship’s course laid accordingly.
The modern mariners’ compass is quite a different arrangement. It
consists of three parts, the _bowl_, the _card_, and the _needle_. The
bowl, which contains the card and needle, is usually a hemispherical
brass receptacle, suspended in a pair of brass rings, called _gimbals_,
in such a manner that the bowl will remain horizontal no matter how
violently the ship may pitch and roll. The card, which is circular, is
divided into 32 equal parts called the _points of the compass_. The
needles, of which there are generally from two to four, are fastened to
the bottom of the card.
Public-domain text, read in full here on John Shaqi.
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