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KF5JRV > TECH 08.10.16 13:36l 30 Lines 1751 Bytes #-3263 (0) @ WW
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Subj: De Magnete
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Sent: 161008/1125Z 3268@KF5JRV.#NWAR.AR.USA.NA BPQ6.0.13
De Magnete
In the 16th century, William Gilbert(1544-1603), the Court Physician to Queen
Elizabeth I, proved that many other substances are electric (from the Greek
word for amber, elektron) and that they have two electrical effects. When
rubbed with fur, amber acquires resinous electricity; glass, however, when
rubbed with silk, acquires vitreous electricity. Electricity repels the same
kind and attracts the opposite kind of electricity. Scientists thought that
the friction actually created the electricity (their word for charge). They
did not realize that an equal amount of opposite electricity remained on the
fur or silk. Dr. William Gilbert, realized that a force was created, when a
piece of amber (resin) was rubbed with wool and attracted light objects. In
describing this property today, we say that the amber is "electrified" or
possesses and "electric charge". These terms are derived from the Greek
word "electron" meaning amber and from this, the term "electricity" was
developed. It was not until the end of the 19th century that this "something"
was found to consist of negative electricity, known today as electrons.
Gilbert also studied magnetism and in 1600 wrote "De magnete" which gave the
first rational explanation to the mysterious ability of the compass needle
to point north-south: the Earth itself was magnetic. "De Magnete" opened the
era of modern physics and astronomy and started a century marked by the great
achievements of Galileo, Kepler, Newton and others.
Gilbert recorded three ways to magnetize a steel needle: by touch with a
loadstone; by cold drawing in a North-South direction; and by exposure for
a long time to the Earth's magnetic field while in a North-South orientation
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