James Clerk Maxwell presents the third of…

James Clerk Maxwell presents the third of his papers regarding electromagnetism, A Dynamical Theory of the Electromagnetic Field to the Royal Society in London, on December 8, 1864, treating light as an electromagnetic wave; he is the first to propose this.

This is the paper in which the original set of four Maxwell's equations first appears.

The concept of displacement current, which he had introduced in his 1861 paper "On Physical Lines of Force", is utilized for the first time, to derive the electromagnetic wave equation.

Maxwell's derivation of the electromagnetic wave equation has been replaced in modern physics by a much less cumbersome method, which combines the corrected version of Ampère's Circuital Law with Faraday's law of electromagnetic induction.