James Clerk Maxwell(1831 — 1879)
James Clerk Maxwell
Royaume-Uni de Grande-Bretagne et d'Irlande
9 min read
Scottish physicist and mathematician (1831–1879), Maxwell authored the unifying equations of electromagnetism. His work predicted the existence of electromagnetic waves and inspired Einstein in developing the theory of special relativity.
Frequently asked questions
Famous Quotes
« The special theory of relativity owes its origins to Maxwell's equations of the electromagnetic field. »
« We can scarcely avoid the conclusion that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena. »
Key Facts
- 1831: born in Edinburgh, Scotland
- 1861–1862: formulation of the equations of electromagnetism (Maxwell's equations)
- 1864: theoretical prediction of the existence of electromagnetic waves
- 1867: major contribution to the kinetic theory of gases (Maxwell–Boltzmann distribution)
- 1879: died in Cambridge at age 48
Works & Achievements
Prize-winning memoir awarded the Adams Prize at Cambridge, in which Maxwell mathematically demonstrates that Saturn's rings can be neither solid nor liquid, but must consist of separate particles in orbit — a conclusion confirmed by Voyager 1 in 1980.
In this paper Maxwell establishes the law governing the distribution of molecular velocities in a gas (the Maxwell-Boltzmann distribution), placing the kinetic theory of gases on rigorous statistical foundations.
A four-part article in which Maxwell introduces the revolutionary concept of the "displacement current" to make the equations of electromagnetism self-consistent. It is in this work that the prediction of electromagnetic waves appears for the first time.
A landmark theoretical synthesis in which Maxwell presents for the first time his unifying equations of electricity, magnetism, and optics, and identifies light as an electromagnetic wave.
Experimental production of the first permanent colour photographic image, obtained by combining three exposures taken through red, green, and blue filters. Publicly demonstrated at the Royal Institution in London on 17 May 1861.
A monumental two-volume encyclopaedic work that gives formal shape to the whole of electromagnetic theory. A standard reference for an entire generation of physicists, it directly influenced Heinrich Hertz, Oliver Lodge, and later Albert Einstein.
Anecdotes
At just 14 years old, Maxwell submitted a paper to the Royal Society of Edinburgh presenting an original geometric method for drawing elliptical curves using a simple thread and two pins. The society, believing they were dealing with an adult, only discovered afterward that the author was a schoolboy. The text was deemed so rigorous that it was read aloud at a session by a professor on his behalf.
On 17 May 1861, Maxwell produced the first permanent color photograph in history, by simultaneously projecting three images taken through red, green, and blue filters. He chose a Scottish tartan ribbon as his subject. This demonstration before the Royal Institution in London astonished the audience and laid the foundations of modern color photography and the color screen.
While deriving his electromagnetic equations, Maxwell calculated that electromagnetic waves propagated at approximately 310,000 km/s — a value very close to the known speed of light at the time. He boldly concluded that light itself was an electromagnetic wave, thereby uniting optics and electromagnetism within a single theory. Einstein later described this discovery as “the greatest transformation in physics since Newton.”
In 1867, Maxwell conceived of a hypothetical microscopic creature capable of sorting fast molecules from slow ones in a gas without expending any energy, seemingly violating the second law of thermodynamics. Dubbed “Maxwell’s Demon” by Lord Kelvin in 1874, this paradox fueled scientific debate for more than a century and helped lay the foundations of information theory.
Maxwell proved through calculation, in a paper awarded the Adams Prize at Cambridge in 1857, that Saturn’s rings could be neither solid nor liquid, but must be composed of millions of independent particles in orbit. A purely theoretical conclusion, it was not confirmed until 1980 by images from the Voyager 1 probe, a century after his death.
Primary Sources
The present state of electrical science seems peculiarly unfavourable to speculation [...] I have therefore thought it might be of some use to exhibit the electrical and magnetic phenomena from a mechanical point of view, so as to give us [...] clear ideas of the action of the medium.
We have strong reason to conclude that light itself — including radiant heat, and other radiations if any — is an electromagnetic disturbance in the form of waves propagated through the electromagnetic field according to electromagnetic laws.
Before I began the study of electricity I resolved to read no mathematics on the subject till I had first read through Faraday's Experimental Researches in Electricity. I was aware that there was supposed to be a difference between Faraday's way of conceiving phenomena and that of the mathematicians.
If we suppose that [...] the number of particles whose velocities lie between v and v+dv is [...] then we have a law of distribution of velocities among the particles of a gas which, if true, will form one of the most important results of the theory.
The conclusion I have arrived at is that the rings must consist of disconnected particles — either solid or liquid — but necessarily in a state of subdivision. The effect of a continuous solid ring would be to give the whole system an angular velocity incapable of being stable.
Key Places
Maxwell's birthplace, where he was born on 13 June 1831 and received his early education at Edinburgh Academy. It was here that, at the age of 14, he wrote his first mathematical paper, which attracted the attention of the Royal Society.
Maxwell studied here from 1850 to 1854, winning the prestigious Smith's Prize jointly with Lord Kelvin. He returned in 1871 as the first Cavendish Professor to found the experimental physics laboratory.
Maxwell was appointed Professor of Natural Philosophy here in 1856, at just 25 years of age. It was in Aberdeen that he wrote his prize-winning essay on the rings of Saturn and deepened his kinetic theory of gases.
Maxwell taught here from 1860 to 1865, the most productive period of his life. It was here that he produced the first colour photograph, developed his equations of electromagnetism, and wrote his landmark 1865 paper on the dynamical theory of the electromagnetic field.
The family estate inherited by Maxwell, where he spent extended periods between 1865 and 1871. It was here, in the tranquillity of the Scottish countryside, that he wrote much of his *Treatise on Electricity and Magnetism*.
Maxwell was the intellectual architect and first director of this laboratory, founded in 1874, which went on to become one of the most important centres of experimental physics in the world. He trained an entire generation of British physicists here.
