William Gilbert

English scientist, physician, and philosopher

• Born: May 24, 1544
• Birthplace: Colchester, Essex, England
• Died: December 10, 1603
• Place of death: London or Colchester, England

Gilbert conducted foundational research in magnetism and electricity and is considered to be the father of electricity studies. He wrote one of the first significant scientific books of the scientific revolution in England and set an early example of experimental methods in science.

Early Life

William Gilbert was born into a middle-class family of rising status in the town of Colchester, about fifty miles northeast of London. His grandfather, William Gilbert of Clare, County Suffolk, was a weaver who rose to prominence as a sewer of the chamber to Henry VIII. One of his nine children, Jerome Gilbert, moved from Clare to Colchester, where he married Elizabeth Coggeshall. Their oldest of five children was William Gilbert of Colchester. After Elizabeth’s death, Jerome married Jane Wingfield.

Following grammar school in Colchester, Gilbert entered St. John’s College at Cambridge University in May, 1558, where he received his bachelor of arts degree and became a fellow in 1561. He completed his master of arts degree in 1564, was appointed as a mathematical examiner in 1565-1566, received his doctor of medicine degree in 1569, and was elected senior fellow of St. John’s College by 1570. Some less substantiated accounts suggest that he also studied at Oxford during some of this time, and that after 1570 he traveled on the Continent, where a doctoral degree in physics might have been conferred on him.

By the early 1570’s Gilbert began to practice medicine in London, where he was elected a fellow of the Royal College of Physicians in 1573. He became a prominent physician in London, serving many clients from the English nobility. In 1577, he was granted a coat of arms by Queen Elizabeth I, evidence of his rising social status. Beginning in 1581, he held several important offices in the Royal College over the next two decades, including censor (editor of journal articles), treasurer, and consiliarium (mediator of disputes).

Life’s Work

Although Gilbert was active in the Royal College of Physicians and conducted important medical and pharmaceutical work, his most important contribution came from nearly twenty years of research on magnetism and electricity. He was one of four physicians in the Royal College requested by the Privy Council in 1588 to provide for the health of the men in the Royal Navy. His early investigations were in chemistry, in which he developed habits of precision that served him well in his pioneering research on magnetism. In 1589 the Royal College assigned him the topic philulae for their publication Pharmacopoeia on the use of drugs. In both 1589 and 1594 he was listed among the examiners for this book.

In London, Gilbert lived at Wingfield House on St. Peter’s Hill, probably inherited from his stepmother. He never married, and he used the house as a laboratory and perhaps as a center for meetings with other scientists and physicians. His work attracted the attention of Queen Elizabeth I, who is said to have given him an unprecedented annual pension to conduct his philosophical studies.

In 1600 he was appointed royal physician to Elizabeth, and after her death on March 24, 1603, he became physician to King James I. Unfortunately, little is known about the details of Gilbert’s life in London because the Great Fire of London of 1666 destroyed records of his past. After Gilbert’s death, probably from the plague, he left his books, instruments, and other scientific equipment to the library of the Royal College of Physicians. Wingfield House and the buildings of the Royal College and its library were all destroyed in the Great Fire.

Gilbert’s most important work was based on his lifetime interest in magnetism. Central to his approach was his rejection of the Aristotelian concept of a corrupt and immobile Earth at the center of perfect rotating celestial spheres carrying the stars and planets in their daily motions across the heavens. Although he did not espouse the new Copernican system with Earth and the other planets revolving around the sun, he did support the idea of a rotating Earth, which makes it unnecessary to require a daily revolution of all the stars and planets around Earth. In magnetism Gilbert saw the possibility of a mechanical explanation for the daily rotation of Earth on its axis.

Gilbert’s study of magnetism was revolutionary in its use of experimental methods and laboratory models in establishing conclusions about the nature of terrestrial magnetism. The growing interest in navigation and the use of the magnetic compass motivated his work, and consultations with seamen helped to keep it on a practical and experimental level. He rejected the accepted explanation that the magnetic poles of the compass needle lined up with the poles of the celestial sphere, and he set about to demonstrate that Earth itself is a magnet causing the alignment of the compass.

Gilbert used lathe-turned spherical lodestones (naturally occurring magnetic stones), each called a terrella (little earth), to act as models of the earth. He then moved small compasses (versoria) over the terrella’s surface to show how they aligned with the poles of the magnetic lodestone. His experiments also revealed the “dip” of the compass needle, with an increasing downward (radial) inclination as it was moved toward a pole of the terrella, and its “declination” from exact polar alignments due to irregularities in the terrella’s spherical shape. Navigators had observed both of these effects in practice, and Gilbert recognized that they could be used as aids in navigation. He also floated terrellae (plural for terrella) on cork rafts to show their rotational tendencies in magnetic alignments.

In the course of his studies of magnetism, Gilbert initiated the field of electricity studies and gave it its modern name when he tried to distinguish magnetism from electrical phenomena. Since the time of the ancient Greeks, it was known that amber rubbed with cloth would attract bits of straw and other light materials. Gilbert now demonstrated that about thirty different materials, including solidified sulfur, glass, and several semiprecious stones, could exhibit the amber effect when rubbed. He designated these materials “electrics,” after the Greek word for amber (electron), and other materials as “non-electrics” if they did not respond in this way when rubbed, such as metals. He invented the first electroscope, or versorium as he called it, for measuring electric attraction by pivoting an unmagnetized horizontal needle on a vertical post, which would then deflect when approached by rubbed electrics.

Significance

Gilbert’s significance as a scientist, natural philosopher, and theorist is evident in a work published during his lifetime: De magnete, magneticisque corporibus, et de magno magnete tellure (1600; A New Natural Philosophy of the Magnet, Magnetic Bodies, and the Great Terrestrial Magnet, 1893; better known as De magnete ). This groundbreaking book was based on nearly two decades of research on magnetism and was published at the pinnacle of his career, a time in which he was appointed royal physician to Queen Elizabeth I.

The book was unusual for its time in its distrust of earlier natural philosophies especially ancient ones and its emphasis on experimental methods, preempting themes later developed by his younger court contemporary Francis Bacon . Ironically, the book was criticized by Bacon for its attempt to develop an entire philosophy based on magnetism.

Whereas Gilbert’s main influence was in initiating the study of magnetism and electricity, and in providing a pre-Baconian example of the importance of experimental methods, significantly, he also questioned ancient authorities and encouraged a new view of the world and its place in the cosmos. He was considered an even greater scientist after another work of his was published, nearly fifty years after his death, by his younger half brother, William Gilbert of Melford. In De mundo nostro sublunari philosophia nova (1651; New Philosophy of the Sublunary World ), Gilbert was more explicit but still cautious about an annual orbit for the earth around the sun, with the “motive power” of both the earth and the moon being magnetic. Although the idea of magnetic motive power was eventually rejected, it provided a temporary explanation for the earth’s motion until the concept of gravitation could be developed further.

Bibliography

Gilbert, William. De magnete. New York: Dover, 1958. This reprint of P. Fleury Mottelay’s 1893 translation of De magnete (1600) includes a nineteen-page biographical memoir by the translator, unfortunately with some inaccuracies.

Pumfrey, Stephen. “William Gilbert.” In Cambridge Scientific Minds, edited by Peter Harman and Simon Mitton. New York: Cambridge University Press, 2002. This is the first chapter in a book about Cambridge scientists that has a good discussion of the context and contributions of Gilbert’s work.

Roller, Duane, and Duane H. D. Roller. The Development of the Concept of Electric Charge. Cambridge, Mass.: Harvard University Press, 1967. The first chapter of this book in the Harvard Case Histories in Experimental Science series describes Gilbert’s electrical studies and theories.

Rossi, Paolo. The Birth of Modern Science. Malden, Mass.: Blackwell, 2001. Chapter 9, “Magnetic Philosophy,” begins with a discussion of Gilbert’s work and the development of Gilbert’s ideas by other scientists in the seventeenth century.