Answer
Magnetism is the scientific principle explored in "De Magnete." This seminal work by William Gilbert, published in 1600, laid the foundation for the study of magnetism. Gilbert conducted extensive experiments with magnets, demonstrating their properties and interactions. He established that the Earth itself is a magnet, explaining the behavior of compasses. "De Magnete" revolutionized the understanding of magnetism and paved the way for further advancements in the field.