What are William Gilberts contributions to electricity?
is a comprehensive review of what was known about the nature of magnetism, and Gilbert added much knowledge through his own experiments. He likened the polarity of the magnet to the polarity of the Earth and built an entire magnetic philosophy on this analogy. In Gilbert’s animistic explanation, magnetism was the soul of the Earth and a perfectly spherical lodestone, when aligned with the Earth’s poles, would spin on its axis, just as the Earth spins on its axis in 24 hours. (In traditional cosmology the Earth was fixed and it was the sphere of the fixed stars, carrying the other heavens with it, that rotated in 24 hours.) Gilbert did not, however, express an opinion as to whether this rotating Earth was at the center of the universe or in orbit around the Sun. Since the Copernican cosmology needed a new physics to undergird it, Copernicans such as Johannes Kepler and Galileo were very interested in Gilbert’s magnetic researches. Galileo’s efforts to make a truly powerful armed lodesto
