The “Souls” of Magnets in the 17th Century

Lodestones are dull, lumpy, and slate-gray, but their “magnetic intelligence” made them fabulously expensive. Magnets have souls. At least, that was the leading scientific explanation for magnetism circa 1600, as laid out in the highly influential De Magnete. Its author, William Gilbert, experimented with lodestones, lumps of magnetite that, after being struck by lightning, turn into natural magnets.[…]