Bringing Maxwell’s theory of electromagnetism to light

James Clerk Maxwell was an incredible British physicist who developed one of the first unified theories of physics, by integrating electricity and magnetism. Between 1861 and 1862 he published a series of papers titled ‘On Physical Lines of Force’, which advanced the revolutionary idea that a change in electric flux through a surface can create a magnetic field. In 1864, he presented his formulation of the classical theory of electromagnetism to The Royal Society of London. It consisted of 20 equations which, for the first time ever, encapsulated the basic rules for bringing together electricity and magnetism, with light being a manifestation of these phenomenon. However, it was neglected because it was deemed too complicated; both mathematically and conceptually. In his 1864 paper, ‘A Dynamical Theory of the Electromagnetic Field’, Maxwell wrote, “The agreement of the results seems to show that light and magnetism are affections of the same substance, and that light is an electromagnetic disturbance propagated through the field according to electromagnetic laws”.

He sadly passed away due to stomach cancer 15 years later, at the age of 48. Ten years after his death, a group of physicists (aptly called Maxwellians) who were interested in the connections between electric and magnetic fields were able to put Maxwell’s theory on solid footing through experiments and gathering empirical data. Heinrich Rudolf Hertz conclusively proved that electromagnetic waves propagate through space at the speed of light and should exhibit the wave-like characteristics of light propagation. By 1885, Oliver Heaviside had reduced the complexity of Maxwell’s theory down to just four equations.

Maxwell’s electromagnetic theory set in motion accomplishments in electrical engineering, telecommunications and physics; laying the foundations for fields such as general relativity and quantum mechanics. Without James Clerk Maxwell, it could have taken decades longer to come up with our modern conceptions of electricity and magnetism, hindering the growth in the development of technology.

Many physicists regard Maxwell as the 19th-century scientist who has had the greatest influence on 20th- century physics. His astounding contributions to science are considered to have the same magnitude of those of Isaac Newton or Albert Einstein, the latter once describing the change in conception of reality brought about by Maxwell’s work as the “most profound and the most fruitful that physics has experienced since the time of Newton”.

Today, in everyday life, it isn’t hard to miss Maxwell’s legacy. There is a grand statue of Maxwell in the city of Edinburgh (his birthplace) and a memorial marker in Westminster Abbey, not far from Isaac Newton’s grave. These monuments are fitting testaments to the impact of his work, as are the daily luxuries we enjoy while his electromagnetic theory underpins so much of the modern world.


This article was written by Ben Millar and edited by Sam Stanfield.


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