Electricity Is a Weightless Fluid That Flows Between Bodies

Benjamin Franklin's one-fluid model of electricity (proposing a single 'electrical fluid' that could be positive or negative in excess) dominated 18th-century thinking and appeared in Britannica as established theory. Electrical phenomena, sparks, shocks, attractions, seemed to confirm fluid flow. The model made predictions that often worked, and it provided intuitive language for discussing electrical phenomena. However, 19th-century advances in electrochemistry, electromagnetic theory, and eventually atomic physics revealed that electricity wasn't a fluid at all, but rather the motion of charged particles (electrons and ions). Maxwell's equations (1860s–1870s) described electromagnetic phenomena without invoking fluid substance. By the late 1800s, J.J. Thomson's discovery of the electron (1897) and Rutherford's nuclear model (1911) vindicated a particulate theory of electricity. Britannica's physics entries gradually shifted language, replacing fluid metaphors with descriptions of charge carriers and fields. Yet the intuitive appeal of electrical fluid persisted in popular discussion and even some pedagogical contexts well into the 20th century.