Chapter 1 - A History of Electricity and Magnetism, to Conservation of Charge

Abstract

This chapter discusses the history of electricity and magnetism and explains the amber effect—the effect by which electricity was discovered. In the 17th century, William Gilbert did a systematic study of the amber effect. Unlike Peregrinus, who used only spherical magnets, Gilbert also used long thin magnets and thus was aware that like magnetic poles repel. By the early 18th century, better generators of electricity (rubbed glass) and better detectors of electricity (cloth threads and leaf brass) had been discovered. The chapter reviews the electric fluid model by Franklin. Franklin's electrical fluid could be transferred; however, like other fluids, it could not be created or destroyed. Thus, it satisfied the conservation law. With the excess electrical fire on the inside driving off electrical fire from the outer surface, despite the impermeable glass, Franklin's model distinguished between conduction of the “electrical virtue” and its effect on matter—such as polarization or electrostatic induction. The early history of electricity shows that early scientists had a difficult time distinguishing the “stuff” of electricity from its effects.