50 Fun Facts About James Clerk Maxwell

The James Clerk Maxwell Telescope stands near the summit of which Hawaiian mountain?

Mauna Kea. Its 15-metre dish is the largest built to work at submillimetre wavelengths, and it is one of the linked telescopes behind the Event Horizon Telescope's pictures of black holes.

Maxwell's unification of light and electricity led him to predict the existence of what?

Radio waves. He never saw them: he died in 1879, and it was only in the following decade that laboratory experiments with electric sparks produced the invisible waves his equations called for.

Which 1865 paper showed electric and magnetic fields travel as waves at the speed of light?

In it he wrote that light "is an electromagnetic disturbance propagated through the field according to electromagnetic laws".

Richard Feynman predicted that Maxwell's laws of electrodynamics would one day outshine which war of the same decade?

The American Civil War. Seen from ten thousand years on, Feynman told his students, it would "pale into provincial insignificance" beside the 1860s' real event, Maxwell's equations.

Who reduced Maxwell's twenty equations to the four now known as Maxwell's equations?

Oliver Heaviside. A telegraph operator who had left school at 16, he found Maxwell's Treatise so gripping that he gave up his job to master it, then recast the equations in the form used today.

Which book of 1873 first set out Maxwell's equations in fully developed form?

A Treatise on Electricity and Magnetism. He wrote most of it not at a university but at home in rural Scotland, in the years between resigning his London chair and going back to Cambridge.

What lies at Maxwell's feet on his statue in George Street, Edinburgh?

His dog. Maxwell kept a succession of terriers called Toby, and one sat between his feet in the Cambridge laboratory, growling, while an electrical machine was worked on its back.

At which country house in Galloway did Maxwell grow up and later write most of his Treatise?

Glenlair. His parents built it; there the small boy asked of everything "What's the go o' that?", and there he later spent six years writing between professorships.

What nickname did Maxwell earn on his first day at Edinburgh Academy in homemade shoes?

Daftie. He arrived in a tunic and square-toed shoes his father had made, speaking broad Galloway, and went home with the tunic in rags; he took no pains to shake the name off.

At just 14, Maxwell wrote his first scientific paper on a way of drawing which curves with pins and thread?

Ovals. He took up the problem after meeting an artist who wanted a way to draw them, and a professor had to read the paper to the Royal Society of Edinburgh because its author was thought too young.

What effect was the teenage Maxwell studying when he viewed twisted jelly through polarising prisms?

Photoelasticity. David Brewster had found the effect; the student Maxwell cast jelly in a ring, twisted it and watched coloured stress patterns appear between prisms made by William Nicol himself.

To which Cambridge college did Maxwell transfer from Peterhouse for an easier fellowship?

Trinity. He left Peterhouse within a term, reckoning a fellowship would be easier to win at the bigger college, and the bet paid off in 1855, sooner than was usual.

Alongside his university posts in Cambridge, Aberdeen and London, Maxwell gave regular evening classes to whom?

Working men. He began the classes at Cambridge, kept a free weekly one going in Aberdeen, and in London went on teaching the artisans for a winter after he had resigned his chair.

William Hopkins, who coached Maxwell at Cambridge, was famed for turning out the university's top graduates in which subject?

Mathematics. Hopkins called Maxwell the most extraordinary man he had met, one who seemed unable to think wrongly on any physical subject, yet in analysis he judged him "far more deficient".

Which three colours of light did Maxwell show would combine to make white, using Forbes's spinning tops?

Red, green and blue. On the spinning top the painters' red, yellow and blue never blurred to a neutral grey; with green in place of yellow they did, and every screen has mixed light that way since.

At which Aberdeen college did Maxwell take the Chair of Natural Philosophy in 1856, aged 25?

Marischal College. He went after a Scottish chair to be near his ailing father, who helped him gather his references and then died weeks before the appointment was announced.

What did Maxwell conclude Saturn's rings must be made of, in the essay that won him the Adams Prize?

Numerous small particles. He proved that a solid ring would be unstable and a fluid one would break up into blobs, which left only a swarm of fragments he called a flight of brick-bats.

Which spacecraft's flybys of the 1980s confirmed Maxwell's conclusion about the rings of Saturn?

Voyager. His prize essay of the 1850s had stood as the last word on the rings for more than a century before the probes' close-up pictures showed that he had been right.

Whose daughter was Katherine Dewar, whom Maxwell married in Aberdeen in 1858?

His college principal's. The Rev. Daniel Dewar had befriended the young professor, and Katherine went on to work in her husband's laboratory, stoking the fire for his experiments on gases.

When his Aberdeen college merged with its neighbour in 1860, what happened to Maxwell?

He was made redundant. The new University of Aberdeen had room for only one professor of natural philosophy and kept the senior man; within months Maxwell held the same chair in London.

Which near-fatal illness did Maxwell recover from in 1860 before moving to London?

Smallpox. He was thought to have caught it at a horse fair that September; his wife nursed him through it alone, and he said afterwards that her care had saved his life.

What did Maxwell present at a London lecture in 1861, photographed for him by Thomas Sutton?

The world's first colour photograph. It was the first that lasted, earlier chemical ones having faded: three black-and-white slides, each taken through a different coloured filter, were projected together through matching filters.

What object did Thomas Sutton photograph three times for Maxwell's famous lecture demonstration of 1861?

A tartan ribbon. Sutton, the inventor of the single-lens reflex camera, shot it on plates so limited that the result was only a partial success, and the method came into its own some forty years later.

For which famous reference work did Maxwell write the articles 'Atom' and 'Attraction'?

Encyclopaedia Britannica. He wrote them for its ninth edition in the 1870s, and his article on capillary action was still being printed, revised by Lord Rayleigh, in the edition of 1911.

Where in London did Maxwell regularly attend lectures and meet the ageing Michael Faraday?

The Royal Institution. Seeing him wedged in the crowd leaving its lecture theatre, Faraday teased the expert on jostling molecules that if any man could find his way through a crowd it should be him.

Maxwell's 1868 paper "On governors" is considered a founding document of which field?

Control theory. A governor is the spinning device that holds a steam engine at a steady speed, and Maxwell's study of when one stays stable was the first mathematical treatment of feedback.

What is the 1867 thought experiment in which an imaginary being sorts particles by energy called?

Maxwell's demon. Maxwell first described only a finite being that could sort fast molecules from slow; it was Lord Kelvin who called it a demon, in print in 1874.

Which physicist generalised Maxwell's gas-velocity theory, giving the distribution its double-barrelled name?

Ludwig Boltzmann. Maxwell's step was to stop following molecules one by one and give a statistical law for their speeds, which turned heat from a certainty into a matter of probabilities.

What did Maxwell sculpt in plaster in 1874 after reading the papers of Willard Gibbs?

A thermodynamic surface. It maps the volume, entropy and energy of an imaginary water-like substance as a landscape; he shaped it in clay with his own hands and posted a plaster cast to Gibbs at Yale.

In 1871 Maxwell returned to Cambridge as the university's first professor of which subject?

Experimental physics. It was a striking post for a man famed as a theorist: he designed the university's new laboratory, watched over every step of its building and chose its apparatus before it opened in 1874.

Maxwell spent his last years editing the unpublished electrical papers of which scientist?

Henry Cavendish. He had printed only two papers on electricity and left some twenty packets of manuscript; Maxwell copied them out in his own hand and repeated many of the experiments himself.

Besides helping to establish the CGS system of units, Maxwell is credited with founding which method?

Dimensional analysis. It let him show that the ratio between the electric and magnetic units of charge had to be a velocity, and measurement put that velocity at the speed of light.

Which idea, now a byword for unpredictability, is Maxwell credited with first emphasising in the 1870s?

The butterfly effect. In an 1873 essay he pointed to "the little spark which kindles the great forest" and "the little spore which blights all the potatoes", moments when the smallest cause decides everything.

From what did Maxwell die in Cambridge on 5 November 1879, aged 48?

Abdominal cancer. It was the disease that had killed his mother, at the same age, when he was eight; his own doctor said afterwards that no man ever met death more consciously or more calmly.

Where is Maxwell buried?

Parton Kirk, near Castle Douglas. His body was taken home from Cambridge to the parish he grew up in; Westminster Abbey has only a memorial stone, laid close to Newton's grave in 1931.

Maxwell's parody 'Rigid Body Sings', beginning 'Gin a body meet a body', borrows which Burns song?

Comin' Through the Rye. He turned Burns's meeting in the rye into a mid-air collision between rigid bodies, and is said to have sung the result to his own guitar.

Maxwell's last public lecture, at Cambridge in 1878, took which brand-new invention as its subject?

The telephone. He cared less for the gadget than for what it stood for, calling it an instance of the benefit to be had from "the cross-fertilisation of the sciences".

Told at Cambridge that he stood on Newton's shoulders, which physicist replied that he stood on Maxwell's?

Albert Einstein. He meant it: on the centenary of Maxwell's birth he called Maxwell's change to our picture of reality "the most profound and the most fruitful that physics has experienced since the time of Newton".

Which German physicist's spark experiments of the 1880s first confirmed Maxwell's great prediction?

Heinrich Hertz. Urged by his teacher to test Maxwell's theory, he first declined; when he did it years later at Karlsruhe he saw no use in the result, only proof that "Maestro Maxwell was right".

Maxwell's 1867 paper On the Dynamical Theory of Gases introduced a model for which type of material?

Viscoelastic materials. The model behaves like a spring and a damper joined end to end: pushed quickly the material resists like an elastic solid, and given time it flows like a liquid.

What invisible medium did Maxwell believe light waves needed, an idea physics later abandoned?

The luminiferous aether. Waves seemed to need something to wave in, but the Michelson-Morley experiment found no trace of it, and special relativity then showed that light needs no medium at all.

What was the profession of Maxwell's father, John Clerk Maxwell of Middlebie?

Advocate. He did only moderate business at the Scottish bar and dabbled in science between cases; he also made his son's square-toed shoes himself, with little thought for how they would look at school.

Which school friend from Edinburgh Academy, later a noted physicist, beat Maxwell to the Edinburgh chair in 1860?

Peter Guthrie Tait. The local paper granted that Maxwell was already one of the most remarkable men known to science, but thought the chair needed someone better at explaining things to pupils who knew nothing.

To which secret Cambridge debating society was Maxwell elected as an undergraduate?

The Apostles. The nickname came from the number twelve, and the society kept both its membership and its discussions secret.

At eight, Maxwell is said to have recited from memory a 176-verse chapter of which book of the Bible?

Psalms. His mother, who taught him at home until her last illness, seems to have prided herself on his memory: he is said to have had Psalm 119, the Bible's longest chapter, by heart at eight.

Which office in the Church of Scotland did the devout Maxwell hold in his later years?

Elder. He served the kirk of his home parish in Galloway, and each year he arranged to leave Cambridge at the end of the Easter term in time to officiate at its midsummer communion.

Robert Davidson, whose exhibition Maxwell was taken to as a ten-year-old, built the first known electric version of what?

A locomotive. Davidson's show in Edinburgh in February 1842 also ran a lathe and a printing press by electricity, and the boy's biographer records the outing as a special treat, "to see electro-magnetic machines".

Which name, still used in vector calculus, did Maxwell coin for the operation that measures rotation in a field?

Curl. In an 1870 letter he first proposed "twist", then "twirl", which he called "sufficiently racy" but perhaps "too dynamical for pure mathematicians", and so settled on curl.

Which paper of 1855, read to the Cambridge Philosophical Society, was Maxwell's first on electromagnetism?

On Faraday's Lines of Force. Faraday, no mathematician, wrote back that he was "at first almost frightened" to see such mathematical force brought to bear on his idea, "and then wondered to see that the subject stood it so well".

Maxwell's colour-matching experiments proved whose earlier theory that the eye has three kinds of colour receptor?

Thomas Young. The polymath who helped decipher the Rosetta Stone had proposed it decades earlier and seen it forgotten; Maxwell revived it and put it on an exact numerical footing.