William Gilbert (1544-1603), an English physician and inventor, first described the properties of the lodestone (magnetic iron ore). Gilbert's De Magnete ("On the Magnet") was published in 1600 and quickly became the standard reference throughout Europe on electrical and magnetic phenomena, influencing astronomers such as Johannes Kepler and Galileo. Gilbert's findings suggested that magnetism was the soul of the Earth, and that a perfectly spherical lodestone, when aligned with the Earth's poles, would spin on its axis, just as the Earth spins on its axis over a period of 24 hours. Gilbert distinguished between magnetism and static (known as the amber effect). He also compared the magnet's polarity to the polarity of the Earth and developed an entire magnetic philosophy on this analogy.
Gilbert - Biography (Hebrew University of Jerusalem, Institute of Chemistry)