In 1600 CE, William Gilbert published De magnete, a work about magnetism and the Earth. In it, Gilbert devotes a chapter to “things which attract in the same manner as amber,” which he calls 'electricks.' In that chapter, he gives long lists of electricks and non-electricks, states many properties of electricks, describes experiments that can be run to verify his claims, offers a theory of electricks, and presents an experimental instrument that others can use to investigate electricks. This is widely considered to constitute the discovery of static electric attraction and the beginning of serious electrical study. Others would later pick up this line of research, build on Gilbert’s observations, and continue to advance the study of electricity.

What led Gilbert to discover static electric attraction? The standard story is that Gilbert was an experimentalist, and that this is what enabled the discovery. Our research shows that this is only half of the truth: Gilbert was an experimentalist, but was also a theorist, and it was his magnetic theory of the heavens and his attempt to reconcile new magnetic data with Copernican astronomy that led him to conduct a careful experimental study of amber and associated materials. We suggest that the lesson from Gilbert’s discovery of static electric attraction is not “a field began when someone started experimenting,” but rather “a field began when a theorist trying to unify two fields was led to experiment in a new area.”