In 1865, the Scottish theoretical physicist James Clerk Maxwell had published two previous papers on electomagnetism, but it was in his "A Dynamical Theory of the Electromagnetic Field" that he did his most important work. He brought together observations that had previously been considered disparate, on electricity, light and magnetic forces, to produce a set of twenty equations formalising the relationship between these. In this paper, he demonstrated that light and electromagnetism existed in the same form, namely waves.
Editors. "Dynamic theory of the electromagnetic field formulated by Maxwell". The Literary Encyclopedia. First published 30 August 2013
[http://www.litencyc.com/php/stopics.php?rec=true&UID=6327, accessed 21 January 2017.]