This 19th century Scottish born scientist is little known to the general public and even unappreciated by some members of the scientific community. Yet his work in uniting three great spheres of physics - electricity, magnetism and light - was instrumental in our modern approach to the subject. This is basically about finding single principles to describe vast areas of natural phenomena. His four key equations of electromagnetism, creating a unified field, with its myriad ramifications, remain the foundation of modern physics. On top of this his kinetic theory of gases accurately explains temperature.
So why is Maxwell not more widely appreciated? Scientists had for centuries noticed a link between
electricity and magnetism. But for all the 17th and 18th
century experiments, no real understanding had emerged about what was going on.
Then in the 19th century Maxwell, working on colour vision, effectively
explained it. The key concept is the field, which spans all of time and space,
and tells other objects how to move. If not the first to imagine such a field, he was the first to harness it and turn it from a mathematical trick into a
real physical entity. One epoch ended and another began with Maxwell. He’s rightly
called ‘the father of modern physics’.
Background and early life
He was born on 13th June 1831 at 14 India
St, Edinburgh. His father was the advocate John Clerk Maxwell of Middlebie, and
his mother Frances, the daughter of Robert Hodshon Cay. The Clerk Maxwells were
a family of considerable means. They held the baronetcy of Penicuik, an estate south of
Edinburgh. James’ uncle, the 6th baronet, was born ‘John Clerk’ but
added Maxwell to his name after inheriting, as an infant, the reduced if still
large Middlebie estate in Dumfriesshire. James’ cousin William Cay was a civil engineer.
He later served as best man at James’ wedding and the two were lifelong close
friends.
Maxwell’s parents were in their thirties when they met and married. Frances was nearly 40 when James was born. She would die from stomach cancer when her son was only eight. The family had moved south, to Galloway in Kircudbrightshire, and a large estate of 1,500 acres. There they built Glenlair, which was to be their home for many years.
So while it would add appeal to the James Clerk
Maxwell story if he’d been born poor, there’s no point in disguising the fact - he was
born into a successful professional family with a long history in Scotland,
with some inherited titles and estates in the south of the country. They were a
pretty talented bunch, too. No fewer than 12 of James’ relations had been
Fellows of the Royal Society and/or the Royal Society of Edinburgh. And not
just in science, either. He grew up in an environment where art was practised
and appreciated. His cousin Jemima was herself a notable painter, as was his
aunt, Jane Cay. Six relatives had been painted by the famous portrait artist
Sir Henry Raeburn. Maxwell the scientist also published his own poetry.
Maxwell showed great curiosity from early on. By the
time he was three, it seems, everything that moved, shone or made a noise drew
the question: “what’s the go (force) o’that?” They soon realised they had a prodigy on
their hands. His mother noticed his inquisitiveness. “He has great work with
locks, keys etc…and he also investigates the hidden course of streams and bell
wires, the way the water gets from the pond through the wall”. She took
responsibility for his early teaching until her death.
His education was then taken over by his father John,
and John’s sister in law Jane. She said, “It was humiliating to be asked so
many questions one couldn’t answer by a child”. There was for a while a
struggle between two aunts as to who should bring him up. He was later placed
under the guidance of a 16 year old private tutor, who being overly strict, chided James for being slow and wayward. He was unsuitable and soon dismissed. In
February 1842 James’ father took him to Robert Davidson’s demonstration of
electric propulsion and magnetic force. This proved strongly influential.
School and University in Edinburgh
James was sent to the Edinburgh Academy but his manner
and accent, plus his clothes, were mocked by classmates, who called him
‘Daftie’. He seems to have borne this without great resentment for years. His
school isolation ended when he made friends with Lewis Campbell and Peter
Guthrie Tait, two boys who later became notable scholars, in Greek and Physics respectively. He won the scripture biography prize in his second year, but his progress went unmarked until at age 13 he won the school’s mathematical
medal and first prize for both English and poetry - he had earlier learned long
passages of Milton and the whole of the Bible’s 119th psalm.
The boy’s interests were not confined to the school syllabus or examinations. A poem of his was published in the Edinburgh Courant when he was 13. Fascinated by geometry early on he rediscovered the regular polyhedral before he’d had any formal teaching. He wrote his first scientific paper at age 14, on drawing mathematical curves and the properties of ellipses, Cartesian ovals and related curves with more than two foci. It was presented to the Edinburgh Royal Society by Prof. James Forbes as Maxwell was deemed too young. The work wasn’t entirely original - Descartes had examined multi-focal ellipses in the 17th century - but Maxwell had simplified their construction.
Aged 16 Maxwell left the Academy in 1847 for Edinburgh University. Here he was not stretched by his studies, despite having some outstanding tutors. In his free time he conducted private experiments in a number of fields. What interested him most were the properties of polarised light, and through stressing blocks of gelatine he discovered photoelasticity. Aged 18 he submitted two papers to the Edinburgh Royal Society. One was on the Equilibrium of Elastic Solids - the basis for the double refraction from stressed viscous liquids. The other was on “Rolling Curves”. Deemed still too young to deliver the papers himself the task fell to his mathematics tutor, Philip Kelland.
Cambridge
In 1850 he left for Cambridge University. While at
Trinity College he was elected to the elite society nicknamed the “Apostles”. He
was a keen Christian but said he examined his faith, putting it to an intellectual
test. With a detailed knowledge of the Bible from his pre-school years his
confidence in the Scriptures came from familiarity. Staying for a time with the
Rev CB Tayler, the caring attitude of the family when James was ill impressed him. Back at Cambridge he wrote a friendly note to Tayler that if he should
escape perdition, “…it is only by God’s
grace helping me to get rid of myself, partially in science, more completely in
society, - but not perfectly except by committing myself to God..”
In 1854 Maxwell graduated, earning the title of ‘Second
Wrangler’. He delivered “On the
transformation of Surfaces by Bending” to the Cambridge Philosophical
Society, one of his few purely mathematical papers. In 1855 he gave the paper “Experiments on Colour”, showing how red,
green and blue would produce white light - to the Edinburgh Royal Society. And
this time he delivered it himself. Later that year he became a fellow of
Trinity. But in 1856 he left to take up the Chair of Natural Philosophy at
Marischal College, Aberdeen. He was 25.
Aberdeen
Besides his departmental responsibilities he lectured 15 hours a week, including a pro bono effort with the local working men’s college. He lived with cousin William Dyce Cay for six months of the academic year, spending the summers at Glenlair. St John’s College Cambridge had chosen for its 1857 Adams Prize topic the rings of Saturn. Maxwell worked hard on this, concluding that the rings comprised numerous small particles. He won the £130 prize for a detailed essay “On the stability of the motion of Saturn’s rings”. In the 1980s Voyager confirmed the particle composition, but we now know the rings’ particles are not stable, being pulled by gravity onto Saturn.
In June 1858 Maxwell married the Marischal Principal’s daughter, Katherine Dewar. She was seven years his senior. Information about her is sparse, but it’s known she worked on viscosity experiments and helped in his laboratory. His biographer Lewis Campbell, was perhaps uncharacteristically reticent about Katherine, while describing their married life as “one of unexampled devotion”. Despite involving his wife in his work, when running the Cavendish Laboratory later in life Maxwell declined to have women there.
In 1860 Marischal merged with the local King’s College to form the University of Aberdeen. With no room for two Natural Philosophy professors, Maxwell was effectively out of a job. But he was offered the Natural Philosophy Chair at King’s College London. And after what was reported as a near fatal bout of smallpox, he and his wife moved south.
London years - electromagnetism
While in London from 1860 to 1865 Maxwell produced his most significant work. He created the first colour photo, developed his theories on the viscosity of gases, and proposed a system of defining physical quantities - dimensional analysis. His electro-magnetism work was revolutionary. In a two-part paper “On physical lines of force” in 1861 he offered a conceptual model for electromagnetic induction. Two later parts covered electrostatics and displacement current, and next, the polarisation of light in a magnetic field, known as the Faraday effect. Maxwell was elected to the Royal Society.
On 5th January 1865, while at King’s,
Maxwell ended a letter to his cousin Charles Cay, “I have also a paper afloat containing an electromagnetic theory of
light, which, till I am convinced to the contrary, I hold to be great guns”.
This was an earth shattering theory. It meant a completely new view of
scientific explanation, unifying three basic forces of physics - electricity,
magnetism and light. Despite 19th century progress in research on electromagnetism
and optics, the various theories all had flaws which proved hard to explain. The
miracle of Maxwell’s discovery was that it swept away the troubles with all
previous theories.
The electric force was crucial in his ideas. He examined the ratio for magnetic to electric forces, determined a few years earlier by German physicist Wilhelm Weber. Maxwell plugged Weber’s force ratio into his equations and was astonished to discover that the velocity exactly equalled the speed of light. His excitement is obvious in his italics when he wrote “We can scarcely avoid the inference that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena”. It is hard to overstate the importance of this discovery to physics. The start of post Newtonian science, it effectively paved the way for the later theories of Relativity and Quantum Mechanics.
Glenlair
In 1865 Maxwell left London and returned with Katherine to Glenlair. He extended the property and found time for some riding and fishing. But he also worked on new areas. In his 1868 paper “On governors”, he mathematically described the behaviour of devices controlling the speed of steam engines, establishing the theoretical basis of control engineering. He wrote the textbook Theory of Heat (1871) and was the first to make explicit use of dimensional analysis.
He also worked on the properties of gases, his wife doing
much of the experimental work on viscosity. Worried the results overturned his
earlier theory, Maxwell admitted it was “the
thoroughly conscious ignorance that is the prelude to every real advance in knowledge”. The problems of the specific heat of gases and much else were explained 35 years later by Planck’s quantum of action, showing that the energy, at the
atomic and subatomic levels, is quantised.
The Cavendish Lab and final years
In 1871 Maxwell returned to Cambridge as Cavendish Professor
of Physics. He was responsible for the newly established Cavendish Laboratory (with
funding from the Duke of Devonshire). It was to become one of the world’s great
scientific research centres. There he edited the work of Henry Cavendish,
including his studies on the density of the Earth and the composition of water.
In 1876 Maxwell was also elected to the American Philosophical Society.
He had become an Elder in the Kirk and remained a
devout Christian all his life. He fell ill in 1879 with the same cancer that
had killed his mother also aged 48. A clerical visitor in his last weeks was surprised
at his lucidity and power of memory. “He
had gauged and fathomed all the schemes and systems of philosophy, and had
found them utterly empty and unsatisfying (the cleric's words) – “unworkable” was his own word about
them – and he turned with simple faith to the Gospel of the Saviour”. Near the
end Maxwell told a colleague, “I have
been thinking how very gently I have always been dealt with. I have never had a
violent shove all my life. The only desire which I can have is like David to
serve my own generation by the will of God, and then fall asleep”.
Maxwell's place in history
The elegant equations in his unified theory are hard to understand, even when reduced to four. Yet the breadth, depth and legacy of thought are clear. “The special theory of relativity owes its origins to Maxwell’s equations of the electromagnetic field” wrote Albert Einstein. Feted for a 1922 Cambridge award, and told by his host he’d done great things standing on Newton’s shoulders, Einstein replied: “No, I stand on the shoulders of Maxwell”. Max Planck said “He achieved greatness unequalled”. In modern times Richard P Feynman said, “From a long view…the most significant event of the 19th century will be judged as Maxwell’s discovery of the laws of electrodynamics”.
Pretty well all we do or experience today relies on Maxwell’s
discoveries, especially his 1860s Kings College London work. Says astrophysicist
Paul Sutter, “With one set of equations, one brilliant leap of intuition and
insight, Maxwell united three great realms of physics: electricity, magnetism
and optics…he’s the scientist responsible for explaining the forces behind the
radio in your car, the magnets on your fridge, the heat of a warm summer day
and the charge on a battery”.
The multi-talented Maxwell loved Scottish poetry and
wrote some of his own. Best known is Rigid Body Sings, based on Burns’ “Comin thro’ the Rye”. He would sing it while playing his guitar. Its opening lines
are:
Gin
a body meet a body,
Flyin’
through the air
Gin
a body, hit a body,
Will
it fly? And where?
With his passing the world lost one of its greatest
minds. Had he lived longer or been less modest, he might be more widely appreciated.
I’ve relied mainly on Campbell’s Life of James Clerk Maxwell, 2010
and Ivan Tolstoy’s James
Clerk Maxwell: a biography (1981)
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