on electric current and magnetism. He demonstrated that a wire carrying a current could deflect a magnetized compass needle. Ørsted's work influenced André-Marie Ampère to produce a theory of electromagnetism. Several scientists speculated that light might be connected with electricity or magnetism. In 1831, Michael Faraday began a series of experiments in which he discovered electromagnetic induction. The relation was mathematically modelled by Faraday's law, which subsequently became one of the four Maxwell equations. Faraday proposed that electromagnetic forces extended into the empty space around the conductor, but did not complete his work involving that proposal. In 1846 Michael Faraday speculated that light was a wave disturbance in a "force field". Expanding upon a series of experiments by Felix Savary, between 1842 and 1850 Joseph Henry performed experiments detecting inductive magnetic effects over a distance of . He was the first (1838–42) to produce high frequency AC electrical oscillations, and to point out and experimentally demonstrate that the discharge of a capacitor under certain conditions is oscillatory, or, as he puts it, consists "of a principal discharge in one direction and then several reflex actions backward and forward, each more feeble than the preceding until equilibrium is attained". This view was also later adopted by Helmholtz, the mathematical demonstration of this fact was first given by Lord Kelvin in his paper on "Transient Electric Currents". Maxwell and the theoretical prediction of electromagnetic waves Between 1861 and 1865, based on the earlier experimental work of Faraday and other scientists and on his own modification to Ampere's law, James Clerk Maxwell developed his theory of electromagnetism, which predicted the existence of electromagnetic waves. In 1873 Maxwell described the theoretical basis of the propagation of electromagnetic waves in his paper to the Royal Society, "A Dynamical Theory of the Electromagnetic Field." This theory united all previously unrelated observations, experiments and equations of electricity, magnetism, and optics into a consistent theory. His set of equations—Maxwell's equations—demonstrated that electricity, magnetism, and light are all manifestations of the same phenomenon, the electromagnetic field. Subsequently, all other classic laws or equations of these disciplines were special cases of Maxwell's equations. Maxwell's work in electromagnetism has been called the "second great unification in physics", after Newton's unification of gravity in the 17th century. Oliver Heaviside, later reformulated Maxwell's original equations into the set of four vector equations that are generally known today as Maxwell's equations. Neither Maxwell nor