William Gilbert

Source

• Born: 24 May 1544
• Birthplace: Colchester, Essex, England
• Died: 30 November 1603 (plague)
• Best Known As: The guy who figured out magnetism and electricity

In 1600 William Gilbert published De Magnete ("On Magnets"), one of the first scientific books in the English language and the first to suggest that the earth was a big magnet. A prominent physician, Gilbert studied magnetism and lodestones for nearly two decades, seeking to explain the behavior of compasses. His book, which also suggested that a vacuum must exist between planets, was a huge success and is considered the first work to discuss the connection between magnetism and electricity. Gilbert was also the royal physician for Queen Elizabeth I and her successor, King James I.

The gilbert, a unit of magnetomotive force, is named after him.

William Gilbert

Library of Congress

[b. Colchester, Essex, England, May 24, 1544, d. London, November 30, 1603]

Gilbert's book De magnete (in English called On the Magnet, Magnetick Bodies Also, and on the Great Magnet the Earth), published in 1600, is among the seminal works of the Scientific Revolution. Gilbert describes his experiments with lodestones and compasses, gives methods of making iron display magnetic effects, introduces the concept of magnetic poles, and recognizes the magnetic field of Earth.

The English physician and physicist William Gilbert (1544-1603), an investigator of electrical and magnetic phenomena, is principally noted for his "Demagnete," one of the first scientific works based on observation and experiment.

William Gilbert was born in Colchester, Suffolk, on May 24, 1544. He studied medicine at St. John's College, Cambridge, graduating in 1573. Four years later he began practicing in London. He was prominent in the College of Physicians and became its president in 1599. The following year he was appointed physician to Queen Elizabeth I, and a few months before his death on Dec. 10, 1603, physician to James I.

In 1600 Gilbert published De magnete (On the Magnet, on Magnetic Bodies, and Concerning That Great Magnet, the Earth: A New Physiology), in Latin. The first major scientific work produced in England, it reflected a new attitude toward scientific investigation. Unlike most medieval thinkers, Gilbert was willing to rely on sense experience and his own observations and experiments rather than the authoritative opinion or deductive philosophy of others. In the treatise he not only collected and reviewed critically older knowledge on the behavior of the magnet and electrified bodies but described his own researches, which he had been conducting for 17 years.

In electrostatics Gilbert coined the word "electricity," greatly extended the number of known materials exhibiting electric attraction, and suggested that static electric attraction was due to a subtle electric effluvium emitted by electrified bodies. The greater bulk of the work, however, is devoted to magnetism. Although the compass had been known in Europe for at least 4 centuries, Gilbert's was the first important study on the detailed behavior of compass needles, their variation from true north, and the tendency of the north pole of the needle to dip. From experiments involving a spherical lodestone, the most powerful magnet then available, Gilbert concluded that the earth was a huge magnet, with a north and south magnetic pole coinciding with the rotational poles. The variation in compass readings from true north, he believed, was due to land masses.

Gilbert also speculated on the nature of magnetism, suggesting that magnetic bodies had a kind of soul which spontaneously attracted other bodies. He pointed out that gravity might be a sort of magnetism, or was at least analogous to it, and that the motions of the planets might well be explained by considering their mutual influence.

Gilbert's studies were so complete and comprehensive that as late as 1822 it was asserted that De magnete contained almost everything known about magnetism. Today the unit of magnetomotive force is called the gilbert.

Further Reading

Gilbert's De magnete (On the Magnet) is available in several translations, such as those of S. P. Thompson and P. Fleury Mottelay. The only complete biography of Gilbert is Silvanus P. Thompson, Gilbert of Colchester: An Elizabethan Magnetizer (1891), which is now difficult to obtain. Romano Harré, Early Seventeenth Century Scientists (1965), has a full chapter on Gilbert. A brief biography is given in George Sarton, Six Wings: Men of Science in the Renaissance (1957). Most standard histories of science discuss Gilbert's contributions. See particularly Abraham Wolf, A History of Science, Technology, and Philosophy in the 16th and 17th Centuries (2 vols., 1939; 2d ed. 1959).

Gilbert, William (1544–1603), English scientist and physician. Gilbert is best known for his revolutionary theories on magnetism, published in his book De Magnete (or De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure; On the loadstone and magnetic bodies, and on the great magnet the Earth) in 1600. Remarkably little is known of Gilbert's life. Born in Colchester to a prosperous magistrate, he received a B.A. from Cambridge University in 1561, an M.A. in 1564, and an M.D. in 1569. By the mid-1570s, he was practicing medicine in London, where he became a member of the Royal College of Physicians (and was elected president of the group in 1600). There, he also came into contact with navigators, compass makers, and practical mathematicians, and pursued his research on magnetism. In his successful medical practice, he was consulted by members of the aristocracy, was appointed as one of Elizabeth I's personal physicians (1600–1603), and, after her death in 1603, served as James I's physician until a plague epidemic that November took his own life.

Navigational accuracy assumed greater importance with the overseas explorations by the Spanish and Portuguese in the fifteenth century, and during the sixteenth century Dutch and English navigators compiled observations that were of significant use to Gilbert. It was not lost on Gilbert or his contemporaries that discoveries about magnetism would be politically and commercially useful. Despite the widespread use of nautical compasses on Spanish, English, Dutch, and French ships, none of his contemporaries understood why compass needles behaved as they did: attraction, repulsion, variation, dip, bipolarity, and the discovery of latitude were recognized empirically, but poorly understood. Through his experiments on magnets and magnetic bodies (especially the lodestone, that is, naturally magnetized iron ore), Gilbert methodically investigated a wide range of magnetic behaviors.

In fact, Gilbert's book went far beyond being a useful navigational treatise, and represented the first comprehensive analysis of magnetism, featuring a revolutionary new theory about the Earth's magnetic force. In formulating his views, Gilbert insisted on using his own empirical data rather than relying on past scientific authorities. His book is full of carefully contrived laboratory experiments that he urged his readers to replicate. He assailed credulous acceptance of myths (such as the power of a magnet to detect adultery), rejected Aristotelian explanations, and invented his own language to describe magnetic phenomena, including the terms electricity, electric force, electric attraction, and magnetic pole. To explain the phenomena he investigated, he concluded that the Earth was alive with magnetic potency or force, and he likened this to sexual attraction. Hence, for him, magnetism was an immaterial, innate force operating in the universe, with occult and vital properties.

The stunning claim of Gilbert's book was that the Earth behaves in the heavens as a spherical magnet does on earth. He based this assertion on his experiments with spherical magnets and on his deduction that the Earth itself was a giant spherical magnet. Reasoning by analogy, he stated boldly that the Earth rotated daily on its own axis by its magnetic power, just as a perfectly spherical lodestone aligned with the Earth's poles would spin on its axis. Declaring himself an adherent of astronomer Nicolaus Copernicus (1473–1543), whose theory about the Earth's rotation around the heavens had been published in 1543, Gilbert added new magnetic arguments to the arsenal of the Copernican polemic.

Influence on Later Science

Subsequent natural philosophers including Francis Bacon (1561–1626) and Galileo Galilei (1564–1642) hailed Gilbert's handling of empirical and experimental evidence, and others applauded his rejection of Aristotle's erroneous ideas about physics and astronomy. Johannes Kepler (1571–1630) and Sir Isaac Newton (1642–1727) pondered Gilbert's magnetic forces before devising their own physical explanations of astronomical motions. And, although many parts of Gilbert's new magnetic theories were soon rejected, including his analogy of the Earth and the spherical lodestone, he is still acknowledged for some of his discoveries about electricity and magnetism (such as the distinction between magnetic and static electricity), and for correctly recognizing that the fixed stars are not all the same distance from the earth.

Bibliography

Gilbert, William. On the Loadstone and Magnetic Bodies, and on the Great Magnet the Earth. Translated by P. Fleury Mottelay. New York, 1958.

Pumfrey, Stephen. Latitude and the Magnetic Earth. Cambridge, U.K., 2002.

Roller, Duane H. D. The De Magnete of William Gilbert. Amsterdam, 1959.

—MARTHA BALDWIN

For other persons named William Gilbert, see William Gilbert (disambiguation).

William Gilbert
Dr. William Gilbert
Born	24 May 1544 Colchester
Died	30 November 1603 London
Occupation	Physician
Known for	Studies of magnetism

William Gilbert, also known as Gilbard, (Colchester, England, 24 May 1544 – London, England, 30 November 1603) was an English physician and natural philosopher. He was an early Copernican, and passionately rejected both the prevailing Aristotelian philosophy and the Scholastic method of university teaching. He is remembered today largely for his book De Magnete (1601), and is credited as one of the originators of the term electricity. He is regarded by some as the father of electrical engineering or electricity and magnetism.^[1] While today he is generally referred to as William Gilbert, he also went under the name of William Gilberd. The latter was used in his and his father's epitaph, the records of the town of Colchester, and in the Biographical Memoir in De Magnete, as well as in the name of The Gilberd School in Colchester, named after Gilbert. A unit of magnetomotive force, also known as magnetic potential, was named the gilbert in his honour.

Contents 1 Life and work 2 See also 3 References 4 Further reading 5 External links

Life and work

Gilbert was educated at St John's College, Cambridge;^[2] after gaining his MD from Cambridge in 1569, and a short spell as bursar of St John's College, he left to practice medicine in London. In 1600 he was elected President of the College of Physicians (not by that point granted a royal charter). From 1601 until his death in 1603, he was Elizabeth I's own physician, and James VI and I renewed his appointment.

His primary scientific work was De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure (On the Magnet and Magnetic Bodies, and on the Great Magnet the Earth) published in 1600. In this work, he describes many of his experiments with his model earth called the terrella. From these experiments, he concluded that the Earth was itself magnetic and that this was the reason compasses point north (previously, some believed that it was the pole star (Polaris) or a large magnetic island on the north pole that attracted the compass). He was the first to argue, correctly, that the centre of the Earth was iron, and he considered an important and related property of magnets was that they can be cut, each forming a new magnet with north and south poles.

The English word electricity was first used in 1646 by Sir Thomas Browne, derived from Gilbert's 1600 New Latin electricus, meaning "like amber". The term had been in use since the 1200s, but Gilbert was the first to use it to mean "like amber in its attractive properties". He recognized that friction with these objects removed a so-called effluvium, which would cause the attraction effect in returning to the object, though he did not realize that this substance (electric charge) was universal to all materials.^[3]

The electric effluvia differ much from air, and as air is the earth's effluvium, so electric bodies have their own distinctive effluvia; and each peculiar effluvium has its own individual power of leading to union, its own movement to its origin, to its fount, and to the body emitting the effluvium.

—De Magnete, English translation by Paul Fleury Mottelay, 1893

In his book, he also studied static electricity using amber; amber is called elektron in Greek, so Gilbert decided to call its effect the electric force. He invented the first electrical measuring instrument, the electroscope, in the form of a pivoted needle he called the versorium.^[4]

Like others of his day, he believed that "crystal" (quartz) was an especially hard form of water, formed from compressed ice:

Lucid gems are made of water; just as Crystal, which has been concreted from clear water, not always by a very great cold, as some used to judge, and by very hard frost, but sometimes by a less severe one, the nature of the soil fashioning it, the humour or juices being shut up in definite cavities, in the way in which spars are produced in mines.

—De Magnete, English translation by Silvanus Phillips Thompson, 1900

Gilbert argued that electricity and magnetism were not the same thing. For evidence, he (incorrectly) pointed out that, while electrical attraction disappeared with heat, magnetic attraction did not (although it is proven that magnetism does in fact become damaged and weakened with heat). It took James Clerk Maxwell to show that both effects were aspects of a single force: electromagnetism. Even then, Maxwell simply surmised this in his A Treatise on Electricity and Magnetism after much analysis. By keeping clarity, Gilbert's strong distinction advanced science for nearly 250 years.

Gilbert's magnetism was the invisible force that many other natural philosophers, such as Kepler, seized upon, incorrectly, as governing the motions that they observed. While not attributing magnetism to attraction among the stars, Gilbert pointed out the motion of the skies was due to earth's rotation, and not the rotation of the spheres, 20 years before Galileo (see external reference below).

Gilbert died on 30 November 1603. His cause of death is thought to have been the bubonic plague.^[5][6]

See also

• Scientific revolution

References

1. ^ Merriam-Webster Collegiate Dictionary, 2000, CD-ROM, version 2.5.
2. ^ William Gilbert in Venn, J. & J. A., Alumni Cantabrigienses, Cambridge University Press, 10 vols, 1922–1958.
3. ^ Niels H. de V. Heathcote (December 1967). "The early meaning of electricity: Some Pseudodoxia Epidemica - I". Annals of Science 23 (4): 261. doi:10.1080/00033796700203316. 
4. ^ Gilbert, William; P. Fleury Mottelay (1893). On the Lodestone and Magnetic Bodies. New York: John Wiley & Sons. pp. 79. http://books.google.com/books?id=UcoEAAAAYAAJ&pg=PA79.  a translation of William Gilbert (1600) Die Magnete, London
5. ^ William Gilbert, brief biography at National High Magnetic Field Laboratory
6. ^ William Gilbert brief biography at bbc.co.uk

Further reading

• Gilbert, William. (1600), De Magnete (About the Magnet). Translated 1893 from Latin to English by Paul Fleury Mottelay, Dover Books, paperback.

• Leary, Warren E. (June 13, 2000). "Celebrating the Book That Ushered In the Age of Sciences …". The New York Times. http://www.nytimes.com/2000/06/13/science/celebrating-the-book-that-ushered-in-the-age-of-science.html?sec=health&&n=Top%2FNews%2FScience%2FTopics%2FPhysics…. Retrieved 2009-03-27. 

• Pumfrey, Stephen; Tilley, David (November 2003). "William Gilbert: Forgotten Genius". Physics World. 

• Pumfrey, Stephen (2002). Latitude & the Magnetic Earth. Icon Books. 

• Shipley, Brian C. (August 2003). "Gilbert, Translated: Silvanus P. Thompson, the Gilbert Club, and the Tercentenary Edition of De Magnete". Canadian Journal o69 f History. http://findarticles.com/p/articles/mi_qa3686/is_200308/ai_n9252195. 

External links

• The Galileo Project — biography of William Gilbert.
• On the Magnet — Translation of De Magnete by Silvanus Thompson for the Gilbert Club, London 1900. Full text, free to read and search. Go to page 9 and read Gilbert saying the earth revolves leading to the motion of the skies.
• The Great Magnet, the Earth — website hosted by NASA — Commemorating the 400th anniversary of "De Magnete" by William Gilbert of Colchester.

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