William Gilbert

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William Gilbert

William Gilbert (also William Gylberde ; born May 24, 1544 in Colchester , Essex , England ; † December 10, 1603 in London or Colchester) was an English doctor and, as a physicist, one of the pioneers of modern scientific research, especially in the field of electricity and magnetism .

Life

Gilbert came from a middle-class family, his father was a lawyer ( recorder ) and citizen of Colchester. William Gilbert was the oldest of the five children from his first marriage (the father married twice more). Gilbert studied from 1558 at St John's College , Cambridge with a bachelor's degree (AB) in 1561 and a master's degree in 1564 and received his doctorate in medicine (MD) in 1569, after which he became a senior fellow of his college. He was retired from the college in 1558, a fellow of the Mr. Symon's Foundation in 1561, was a mathematical examinor in 1565/66 and a senior bursar in 1569 and 1570. He may have gone abroad after completing his medical degree at Cambridge, but there is no specific evidence. In the mid-1570s he settled in London as a doctor. In 1577 he received a letter of arms . He became (before 1581) a member of the Royal College of Physicians and around 1581 was one of the most respected doctors in London with many high-ranking patients. In 1588 he was one of the college's four doctors who took care of the Royal Navy's health on behalf of the government . In 1600 he became president of the Royal College of Physicians, having had official positions there since 1582 and working on their pharmacopeia. In 1600 he received the post of court physician to Queen Elizabeth I , after her death at the court of King James I. He lived in Wingfield House in St. Peters Hill in London, probably an inheritance from his stepmother, and had his laboratory there. He may have died of the plague and bequeathed his instruments and books to the Royal College of Physicians. The estate, library and house, like the Royal College, were destroyed by the Great Fire of London in September 1666.

plant

Gilbert is considered to be the first researcher to systematically research the properties of magnetic ores through carefully planned experiments . He also refuted some of the legends that had developed around magnetic phenomena - for example, that garlic could demagnetize a magnet.

With his investigations into vis electrica (he also used this word) he introduced the theory of electricity . He was the first to clearly differentiate between magnetism and static electricity (De Magnete, Book 2, Chapter 2), and investigated the electrical charge on many substances (not only on the eponymous amber ). He attributed magnetism to the earth as a whole and its real components (such as magnetite and iron). On the other hand, in Gilbert's opinion, the electrical effect of amber after friction was a remnant of the liquid nature of amber, which arose from solidified liquids in the earth: According to this, a liquid emerges that absorbs small particles and draws them inward. In addition to amber, he found other electrical substances and produced the first modern electrical measuring device, an electroscope , which he called the " Versorium ". According to his own statements, it consisted of a metal three or four fingers long, which was placed flexibly on a sharp point.

Gilbert's spherical magnet "Terrella" together with magnetic needles

While some of his contemporaries believed that the tip of the compass needle was attracted to the North Star , he showed convincingly that the earth as a whole must be viewed as a single magnet with two poles (De Magnete, last chapter of Book 1). He also concluded this from the inclination of the magnetic needles discovered by Georg Hartmann and made famous by Robert Norman (The New Attractive 1581) . However, his own experiments with a spherical magnet that he called “Terrella” (Latin for “small earth”) were decisive. According to him, magnetism was the “soul” of the earth and was implanted in it by God. He assigned an area of ​​influence to each magnet, a forerunner of the field concept. He suggested that seafarers record deviations from the direction of the magnetic needle to the North Pole and gave instructions for this.

His main work De Magnete, Magnetisque Corporibus, et de Magno Magnete Tellure (About Magnets, Magnetic Bodies and the Great Magnet Earth) appeared in 1600 and gives a broad overview of his research on magnetism and the phenomena of electricity. It was well received in England and also on the continent and was reprinted in 1628 and 1633. It is the first comprehensive treatment of magnetism since Petrus Peregrinus de Maricourt in the 13th century.

Gilbert, like Peregrinus, believed that rotation was a magnetic movement and that a balanced spherical magnet would perform a rotary movement. In the sixth book of his De Magnete , in which he transferred his magnetic philosophy to the cosmos, he took the view that the daily rotation of the earth was due to magnetism. He rejected the idea of ​​a fixed star sphere with a fixed distance. He also tried to attribute the tides and the precession of the equinoxes to magnetism; but his arguments for this were weak and the sixth book of his major work was therefore criticized by Francis Bacon and others. Gilbert's contemporaries valued his achievements as a physicist highly; Johannes Kepler and Galileo Galilei, for example, were very interested in his explanations on the rotation of the earth. Kepler tried to use Gilbert's magnetic theory to drive planetary motion, but failed because of too many ad hoc assumptions that had to be made.

A collection of unfinished Gilbert writings was collected in 1651 by his half-brother William Gilbert of Melford under the title De Mundo Nostro Sublunari Philosophia Nova (New Philosophy About Our Sublunar World) and were known, for example, by Francis Bacon and Thomas Harriot . They were published in Amsterdam in 1651. It was unfinished and the first part (Physiologiae nova contra Aristotelem, probably 1590s) continued the cosmological ideas from De magnete's last book and assumed its concepts. The irregular movements of the moon around the earth and its rotation are also determined by the magnetism of matter - he found the libration of the moon and from him comes the only map of the moon before the invention of the telescope.

The second part, Nova meterorologia contra Aristotelem , was probably created as an independent work and deals with comets, the Milky Way, rainbows, clouds, wind, tides and the sea, the origins of rivers and others. The posthumous writings were by far not as influential as his main work, which proved to be groundbreaking for the scientific research of the following generations. In Physiologia he denies the existence of Aristotle's four elements and replaces them with a single one, earth. Its characteristic property was magnetism. Parts of the earth without magnetic properties are degenerate forms of the earth and most liquids are effluvia of this basic element earth. The other celestial bodies were constructed similarly according to Gilbert, even if he only formulated it explicitly for the moon. According to Gilbert, this was a reduced earth with seas (the lighter areas) and continents. Like the stars, the sun was a light-emitting body in contrast to the five planets that orbited the sun and were propelled by it as a driving magnetic force on their orbits. He excluded the earth from this drive by the sun, although like the other planets it was in its magnetic sphere of influence. He discussed the ideas of Nicolaus Copernicus and Giordano Bruno, but did not explicitly support or oppose the heliocentric worldview. As in other places, the unfinished character of the posthumous writings, some of which are compilatory in nature, is evident here.

In his treatment of the Milky Way (the exact nature of which he leaves open) he also mentions that it is best observed with an instrument called a specillis , which he does not describe in detail.

Honors

The Gilbert , a cgs unit for magnetic tension, was named after him. The lunar crater Gilbert is named after him and the geologist Grove Karl Gilbert . He is also the namesake of Mount Gilbert in Antarctica. The William Gilbert Award of the American Geophysical Union for paleo- and geomagnetism is named after him.

Works

  • Tractatus, sive physiologia nova de magnets, magneticisque corporibus et de magno magnets tellure. Sex libris comprehensus , 1600 (digitized: Issue Stettin / Rostock in 1628 , output Szczecin 1633 )
  • English translation of his main work: On the magnet, magnetick bodies also, and on the great magnet the earth , translator: Silvanus Phillips Thompson, Chiswick Press, London, 1900 ( online at Projekt Gutenberg ).
  • On the loadstone and magnetic bodies and of the great magnet the earth, Wiley 1893, Archive
  • Duane Roller: The De magnets of William Gilbert, Amsterdam 1959
  • De mundo nostro sublunari philosophia nova, collected by his half brother, Amsterdam 1651 (new edition Suzanne Kelly: The De mundo of William Gilbert, Amsterdam 1965)

literature

Web links

Commons : William Gilbert  - Collection of Images, Videos and Audio Files

Individual evidence

  1. ↑ Kelly, Article Gilbert, Dictionary of Scientific Biography
  2. ^ Sattelberg: From electron to electronics , pp. 22-23.
  3. ↑ a b Sattelberg: From electron to electronics , p. 24.
  4. ↑ Kelly, Dict. Sci. Biogr.
  5. ↑ Kelly, Dict. Sci. Biogr.
  6. ↑ Stephen Pumfrey: Harriot's Maps of the Moon: New Interpretations. Notes Rec. R. Soc. 63, 2009, doi: 10.1098 / rsnr.2008.0062 .
personal data
SURNAME Gilbert, William
ALTERNATIVE NAMES Gylberde, William
BRIEF DESCRIPTION English doctor and naturalist
DATE OF BIRTH May 24, 1544
PLACE OF BIRTH Colchester , Essex , England
DATE OF DEATH December 10, 1603
Place of death London or Colchester