Strange Attraction
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Strange Attraction Each year, several million töns of metal are produced for use as magnetic materials in many everyday devices and processes common to all of us — from radio communication, information storage, telephone receivers, and stereo Speakers to electric motors, transformers, and generators. All these things would have completely baffled the shepherd Magnes 2500 years ago when, according to legend, he stepped on a lodestone (magnetite). Pliny the Eider wrote of Magnes, "the nails of whose shoes and the [iron] tip of whose staff stuck fast in a magnetick field while he pastured his flocks." The Roman philosopher and poet Lucretius, writing in the first Century B.C., ascribed the name "magnet" to the Greek province of Magnesia in Thessaly, where magnetite was first mined. In 500 B.C. Thaies of Miletius related that magnetite would pick up small pieces of iron and other bits of magnetite. According to Plato, Socrates claimed that a large enough lodestone could support by magnetic attraction a chain made of iron rings. Magnetite, or lodestone, is a natural magnetic oxide of iron (Fe304), a black opaque mineral of the spinel group with a metallic luster. Today, magnetite is found in commercial quantities in Norway, Sweden, the Ural Mountains, and in some parts of the United States. The ancients seemed to view magnetite as a plaything and a curiosity. Lucretius mentioned that "sometimes, too, iron draws back from this stone, for it is wont to flee from and follow it in turn." To explain this phenomena, some of the ancients proposed that the surface of a magnet was covered with tiny hooks, while pieces öf iron were covered with little rings to catch the hooks. Other philosophers claimed that magnetite emitted particles, leaving an empty place around the stone into which a piece of iron could move. The term lodestone means "leading stone," which refers to its ability to be üsed as a compass. The ancient Greeks do not appear to have known of the compass, but some writers suggest that the Chinese had been using compasses for land travel as early as the 26th Century B.C. The Englishman Alexander Neckam (1157-1217) gives the first known European reference to a compass, and in 1269 the French crusader MRS BULLETIN/JUNE 1988
Petrus Peregrinus de Maricourt (Peter the Pilgrim) described in detail the use of a compass for navigation. He believed that the lodestone derived its power from the sky. Apparently ön one of his long voyages, Peter the Pilgrim played with a sphere of magnetite, exploring its surface with bits of iron. He discovered that lines of magnetic force circled the sphere and seemed to intersect at two opposite places on the globe, which he named "poles" in analogy to the Earth's poles. It wasn't until more than three centuries later in 1600, though, that William Gilbert, physician to Queen Elizabeth I, proposed that the Earth itself was a magnet. Gilbert summarized his awe of magnetism by writing: "Magnetick force is animate, or imitates life; and in many things surpasses human life, [which] is bound up in
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