De Magnete

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De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure (On the Magnet and Magnetic Bodies, and on That Great Magnet the Earth) is a scientific work published in 1600 by the English physician and scientist William Gilbert.

In this work Gilbert describes many of his experiments with his model earth called the terrella. From the experiments, he arrived at the remarkable conclusion that the Earth was magnetic and that this was why the compass pointed north. (Previously, it was thought that Polaris or a large magnetic island at the North Pole attracted the compass). In his book, he also studied static electricity produced by amber. Amber is called elektron in Greek, and electrum in Latin, so Gilbert decided to refer to the phenomenon by the adjective electricus and the noun electricitas, giving rise to the modern terms 'electric' and 'electricity'.

De Magnete was influential not only because of the inherent interest of its subject matter, but also for the rigorous way in which Gilbert described his experiments and his rejection of ancient theories of magnetism. Gilbert nevertheless acknowledged his debt to Peter of Maricourt and incorporated this thirteenth century scientist's experiments on magnetism into his own treatise.^[1] Although his thinking was heavily influenced by the mysticism of his time, Gilbert was also one of the pioneers of experimental physics.

1 Summary
2 Editions
3 Notes
4 References

[edit] Summary

De Magnete consists of six books.

Historical survey of magnetism and theory of Earth's magnetism.
Distinction between electricity and magnetism. Argument against perpetual motion.
The terrella experiments.
Declination (the variation of magnetic north with location).
Magnetic dip and Design of the magnetic inclinometer.
Magnetic theory of stellar and terrestrial motion. Precession of the equinox.

[edit] Editions

De Magnete, Peter Short, London, 1600 (original Latin)
De Magnete, English translation by Paul Fleury Mottelay, 1893
De Magnete, translation by Silvanus P Thompson, Chiswick Press, 1900
De Magnete, facsimile of Thompson translation, Basic Books, New York, 1958
De Magnete, facsimile of Mottelay translation, Dover Books, 1991, ISBN 0-486-26761-X