William Gilbert was born on 24 May 1544 in Colchester, England, and received his MD from Cambridge University in 1569. His research in the field of medicine was not outstanding, and his greatest contribution to the scientific community was the study of the Earth's magnetic field. In 1600 he published The Theory of Magnets, the first scientific treatise in the history of physics to systematically expound magnetism. Galileo called it "great to the point of envy."
Gilbert did some important research on the Earth's magnetic field. In the era, many capitalists explored the world, traveled around the world very much, and the magnetic compass became a very important tool, although no one knew how it worked. Gilbert discussed the operation of the compass needle with the captain and navigator, and experimentally refuted many superstitious rumors or practices, such as rubbing the compass with garlic and even people using the taste of garlic in their mouths to cause the compass to fail. Later he made some natural magnets that were called natural magnets in nature into magnetic spheres, and he called the gate "Little Earth". He studied the magnetism of the spheres with magnetic needles that could swirl around them. Gilbert found that the motion of these magnetic needles resembled the behavior of compass needles located in different locations on Earth, and speculated that Earth had an iron nucleus that resembled a bar magnet, which had an north pole and an antarctic. Before his experiments, scientists had thought that compass needles were pointing north because they were attracted to the North Star, or because there was a large magnetic island at the geographic North Pole.
Gilbert studied its "Little Earths" and realized that because the opposite-sex magnetic poles attract each other, the end of the magnet pointing north (the geomagnetic north pole pointing to the Earth) should be called the south pole. Gilbert once said: "All those who have marked the poles of natural magnets so far, all the instrument makers and navigators, have surprisingly mistaken the end of the magnet toward the north as the North Pole and the south end as the South Pole, and we will prove this to be a mistake in the future." The whole discipline of magnetism has developed so wrong that even its basic principles are wrong."
In fact, it was Gilbert who introduced terms such as "magnetic pole" and "electric field intensity" into human language. He first recognized that "magnetism" and "electricity" are two different phenomena, and his achievements in magnetism did not progress for two hundred years until Faraday began to study magnetism.