It is often said that after Charles Augustin de Coulomb, Carl Friedrich Gauss, André Marie Ampère, and Michael Faraday discovered the four experimental laws concerning electricity and magnetism, James Clerk Maxwell added the displacement current and thereby created the great set of Maxwell’s equations. That view is not entirely wrong, but it obscures the subtle interplay between sophisticated geometrical and physical intuitions that led not only to the replacement of “action at a distance” by field theory in the 19th century but also, in the 20th century, to the very successful standard model of particle physics.
In 1820 Hans Christian Oersted (1777–1851) discovered that an electric current would always cause magnetic needles in its neighborhood to move. The discovery electrified the whole of Europe and led to the successful mathematical theory of “action at a distance” by Ampère (1775–1836). In England, Faraday (1791–1867) was also greatly excited by Oersted’s discovery....
