William Gilbert, a practicing physician who attended Queen Elizabeth I throughout the last difficult years of her reign, was most noted in his time as a keen astronomical observer. But by far his most enduring accomplishment was a six-volume work compiling all knowledge of electricity and magnetism. Titled On The Magnet, it published in 1600, the year when, also in London, Shakespeare wrote Hamlet.
Gilbert is considered the father of electricity, and for good reason. Besides recording knowledge from the past, he was an avid experimenter and educator, creating an enduring terminology that is in use 400 years later. To him we owe the terms “electricity” and “electrical force,” and the concepts of electrical attraction and the magnetic poles.
On The Magnet, relating Gilbert’s vast amount of experimentation as well as knowledge from the past, is characterized by the author’s commitment to scientific method. Experimentation and study of source material available to him led Gilbert to the counter-intuitive conclusion that the earth is one enormous magnet. Going a step farther, he concluded that deep within the earth there is a core of iron. By experiment, he showed that when a magnet is cut, each segment will retain magnetic properties including its own north and south poles.
Gilbert’s On The Magnet was at the time widely read throughout Europe, where it could be understood by all educated individuals because it was written in Latin. Previously, information about lodestone and magnetized iron was almost nonexistent. It was widely believed that garlic brought close to a needle would compromise its ability to remain magnetized. Gilbert’s experimental approach, as opposed to relying on Aristotle and other ancients, refuted this and similar myths and set new standards for future researchers. Test and measure replaced read and believe.
It is thought that when Gilbert died in 1603, the cause was bubonic plague. Despite this painful and premature conclusion to his life, his spirit endures in the great technology his work enabled. He is honored today by the fact that the gilbert is the unit of measurement for magnetomotive force just as the volt is the unit of measurement for electromotive force.