by Brian Clegg
PROFESSOR
MAXWELL’S
DUPLICITOUS
DEMON
THE LIFE AND SCIENCE OF
JAMES CLERK MAXWELL
BRIAN CLEGG
Contents
Title Page
Dedication
Acknowledgements
Demonic Interlude I: In which the demon is summoned
Chapter 1: Not a little uncouth in his manners
Edinburgh and Glenlair
The Academy
The young mathematician
Churchman and country squire
The university life
A particular light
The path to Cambridge
Demonic Interlude II: In which electricity meets magnetism
Natural electricity
From the skies to the laboratory
Magnetic matter
The birth of electromagnetism
A matter of speculation
Chapter 2: A most original young man
Stepping up to Trinity
Becoming an Apostle
Cats and rhymes
The Wranglers
Colour vision
The true primaries
A peculiar inability
Quantifying Faraday’s fields
For the benefit of working men
A new destination
Demonic Interlude III: In which atoms become real and heat gets moving
Atoms exist
A better model of heat
Chapter 3: The young professor
A city divided
His lectures were terrible
Lord of the rings
Life in Aberdeen
E pur si muove
Statistics to the rescue
A new family
Accommodating the British Ass
Leaving Aberdeen
Demonic Interlude IV: In which the demon’s challenge is posed
The tyranny of the second law
The demon is summoned
Doing it without energy
Chapter 4: A capital adventure
Science at King’s
Bring colour to the Institution
Electromagnetism goes mechanical
Maxwell’s electromagnetic spheres
Vortices and idle wheels
The power of analogy
Demonic Interlude V: In which the demon becomes a star
Victorian computer dating
The demon’s catechism
Chapter 5: Seeing the light
The power of flexible cells
Waves in the ether
Seeing the light
Too heavy for one person to discharge
The Great London Exposition
Chapter 6: Science by numbers
The viscosity engine
Stereoscopes and coffins
A standard for resistance
The velocity of a resistor
Electromagnetism without visible support
In the mathematical belfry
A new physics
The beautiful equations
Getting away from it all
Demonic Interlude VI: In which the demon suffers a setback
The cost of measurement
Chapter 7: On the estate
Glenlair life
Back to viscosity
The wine merchant’s batteries
Meet the governor
Thinking in four dimensions
The life academic
Chapter 8: Cambridge beckons
The Cavendish connection
A different professor
The last second home
Ancient lights and modern physics
A slow start
Women in the laboratory
Demonic Interlude VII: In which the demon’s memory is challenged
Forgetting is never easy
Chapter 9: The last work
Books and the power of light
The Cavendish papers
Passing fancies
A sudden end
Demonic Interlude VIII: In which the demon lives on to fight another day
The reality of loopholes
Chapter 10: The legacy
Index
About the Author
Also by Brian Clegg
Copyright
For Gillian, Rebecca and Chelsea
Acknowledgements
As always, thanks to the brilliant team at Icon Books who were involved in producing this book, notably Duncan Heath.
Thanks also to the various experts who have written on James Clerk Maxwell, and to the help from David Forfar and John Arthur of the James Clerk Maxwell Society.
Demonic Interlude I
In which the demon is summoned
I appreciate that demons rarely feature in popular science titles. Not even in books on the god particle,* which is somewhat remiss. Yet a demon I am. I was originally summoned into being by the eminently respectable, God-fearing Scottish professor James Clerk Maxwell, and proclaimed to be a demon by his fellow Scot and physicist William Thomson. I was born – as are so many things in your universe – out of the second law of thermodynamics.
This ‘law of thermodynamics’ business may sound boringly mired in the steam age, and that’s certainly how it originated. But the second law determines how the universe works. Strictly speaking, incidentally, the second law is the third law, as an extra one was added in at the top of the list after the first two were proclaimed, but to avoid – or possibly cause – confusion, the late-comer was named the zeroth law. The second law can be phrased in two ways, either of which sounds perfectly innocuous. Yet in those simple statements lie the foundations of reality and the doom of everything.
It’s the second law that decides that effect follows inevitably from cause. It’s the second law that ensures that books on perpetual motion machines remain on the fiction shelves in the library. Indeed, it’s the second law that determines the flow of time in your world (it’s far more flexible in mine). If you could prove that the second law could be broken, you would set chaos loose to reign in the world. As a demon, this sounds an attractive proposition – and it’s appropriate, as breaking that law is exactly what I was created to do.
How does my charge sheet read? You can either say that the law states that heat passes from a hotter to a colder body, or that entropy – the measure of the disorder in a system – always stays the same or increases. But I was brought into being to challenge this law. Do you think it doesn’t matter if some piddling law of physics is broken? This is the law that explains why a dropped glass breaks and never unbreaks. It makes it possible for life to exist on Earth and it predicts the end of the universe. And without it, the many engines that your lives depend on, from cars to computers, would fail. So, don’t disrespect the second law.
The early twentieth-century English physicist and science writer Arthur Eddington† said: ‘If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations [James Clerk M’s masterpiece that describe how electromagnetism works] – then so much the worse for Maxwell’s equations. If it is found to be contradicted by observation – well these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in the deepest humiliation.’
Which raises the curtain for me. My sole purpose in life is to show that the second law of thermodynamics can indeed be broken. I enable heat to travel from a colder to a hotter place. Uncomfortably for a demon, I am able to reduce the level of disorder in the world. And if I can truly achieve this, it’s not me, but ev
ery physicist since Victorian times who must collapse in the deepest humiliation.
I am, as Churchill might have put it, a riddle, wrapped in a mystery, inside an enigma. Whether anyone has been able to find the key to defeat me remains to be seen in the pages to come. But first, we need to discover the young James Clerk Maxwell.
At the risk of sounding like Frankenstein’s monster, prepare to meet my creator.
* For those not familiar with this term, it is a nickname for the Higgs boson, which came to public attention when it was discovered using the Large Hadron Collider at CERN in 2012. Amusingly for those of us with demonic tendencies, physicist Leon Lederman wanted to call his book on the search for the particle The Goddamn Particle, because the Higgs was such a pain to pin down. The publishers objected that this might be considered too irreverent by the public and resorted to the misleading alternative of The God Particle, which really winds up most physicists.
† A man totally lacking in the wondrous beard sported by each of his Scottish counterparts.
Chapter 1
Not a little uncouth in his manners
There was nothing to suggest the coming of a demon in James Clerk Maxwell’s early life. We ought to get that convoluted name untangled first of all. Over the years, those writing about him have never been sure what to call him. Some have resorted to Clerk Maxwell or even an approach he would never have countenanced, the hyphenated Clerk-Maxwell, but his name was not really double-barrelled and ‘Maxwell’ does the job far better.
Maxwell’s father was originally called John Clerk (pronounced to rhyme with ‘park’). This family, existing on the boundary between the upper middle class and the aristocracy, had a complex history. One of Maxwell’s distant ancestors, another John Clerk, had bought the vast lowland Scottish estate of Penicuik, and with it a baronetcy* back in 1646. His second grandson married an Agnes Maxwell, who brought with her the equally impressive estate of Middlebie. Over the years (and quite a lot of intermarrying of cousins) the name ‘Clerk’ was always associated with Penicuik and Maxwell with Middlebie – and when appropriately named cousins came together, they sometimes took the name Clerk Maxwell.
By Maxwell’s father’s time, Middlebie was only a shadow of its former self, a ‘small’ 1,500-acre (600-hectare) holding, which is why their estate house ended up a good 30 miles from the town of Middlebie itself. The rest of the estate was sold off to cover some risky speculation in mining and manufacturing by Maxwell’s great-grandfather. John Clerk’s older brother George was the principal heir, but part of John’s inheritance was what was left of the Middlebie estate. This was not an act of generosity on George Clerk’s part. The estate was entailed such that Middlebie and Penicuik could not be held together – otherwise, he would likely have held on to the whole thing. Splitting estates was considered bad form. When John Clerk received this new position, he took the traditional laird’s name, tacking ‘Maxwell’ on after Clerk.
Edinburgh and Glenlair
James Clerk Maxwell was born on 13 June 1831, at his parents’ home, 14 India Street, Edinburgh – now, appropriately enough, the home of the James Clerk Maxwell Foundation. This was a three-storey townhouse on a cobbled street set back from Queen Street, one of the three parallel roads that form the heart of the city. Maxwell was a late and, in all probability, a spoiled child. His mother, Frances Cay before marriage, had lost her first child Elizabeth as a baby. Frances was almost forty when Maxwell turned up.
Maxwell’s father, John, had been a successful advocate (the Scottish equivalent of a barrister), but by the time Maxwell was two, John Clerk Maxwell had settled into his new role of country landowner. The family left the Edinburgh house behind, still owning it but renting it out throughout Maxwell’s life. Middlebie had no grand manor, unlike brother George’s imposing Palladian-style Penicuik House,† but John and Frances arranged for a relatively humble home, Glenlair, to be built for them on the farmland known as Nether Corsock.
The social distance between the lively city of Edinburgh and the rural isolation of Middlebie was far more than the 80 or so miles between them suggests. Edinburgh was a modern Victorian city, encouraging scientific and literary thought. Middlebie might as well have remained stuck two centuries in the past. And that 80 miles was made to seem greater still by the difficulties of travelling in rural parts of Scotland. The route, via Beattock, took two complete days, needing a stop along the way. The vehicles available were hardly state-of-the-art. In the biography of Maxwell written just three years after his death by Lewis Campbell, a lifelong friend since school who became a professor of classics, and William Garnett, another friend who was an English electrical engineer, it is noted that:
Carriages in the modern sense were hardly known to the Vale of Urr. A sort of double-gig with a hood was the best apology for a travelling coach, and the most active mode of locomotion was in a kind of rough dog-cart, known in the family speech as a ‘hurly’.
It’s indicative of John’s nature – which seems to have been inherited by his son – that when outbuildings were added to the house in 1841, not only did John plan what was required, he drew up the working plans for the builders to use. Although he was a lawyer, according to Maxwell’s early biographers, when not on a case, John ‘dabbled between-whiles in scientific experiment’. He even published a paper in The Edinburgh New Philosophical Journal on an automated printing device entitled ‘Outline of a plan for combining machinery with the mechanical printing-press’. John Clerk Maxwell was exactly the right kind of father to encourage his son to take an interest in the natural world.
Maxwell’s first eight years must have seemed idyllic for a well-off child of the period. His parents allowed him remarkable freedom, neither preventing him from mixing with the local farm children, nor beating out of him the thick Galloway accent he picked up from his friends, which surely must have put a strain on their class-driven sensibilities. In fact, they seem to have been unusually unstuffy for a Victorian family.‡ Theirs was a home where there was little room for formality, but plenty of humour, an approach to life that would later stand Maxwell in good stead.
The estate combined the contrasting terrains of moorland and farmland and ran alongside the curving banks of the River Urr. A small burn feeding the Urr ran at the edge of the meadow beyond the house. By digging out a hollow in the bed of the burn, the Maxwells provided themselves with a swimming pool. Though it would have been freezing cold even at the height of summer, it was no doubt a great attraction for the young Maxwell.
Given their relative wealth, the Maxwells could have readily afforded a tutor for their son. It’s telling that when Mary Godwin (later Mary Shelley), the author of Frankenstein, was young, her family was described as being of a ‘very restricted income’, yet her brothers were sent to boarding school and she had ‘tutors in music and drawing as well as a governess’. The Maxwell family was far better off than the Godwins, but displaying an unusual interest in her child for a wealthy parent of the day, Frances looked after Maxwell’s schooling herself. Things would soon change, though. The death of Frances from abdominal cancer in 1839, aged just 47, must have caused the bottom to drop out of the eight-year-old James’s world.
While his father, John, had certainly gone along with Frances’ wish to devote her time to raising the boy, he either wasn’t able or didn’t wish to do the same himself. It was one thing to let the young Maxwell play with his local contemporaries, but the nearby schools were very limited in their educational standards and John could not see his son attending one. For a while, he tried out a young man as a tutor, just sixteen when he took on the job. The teenager had neither the talent nor the experience to keep the bright and curious young Maxwell interested and his efforts failed miserably. Maxwell became difficult and would not accept his lead.
The tutor (whom Maxwell later felt it inappropriate to name) was also rough, even by the standards of the period. Maxwell’s experience apparently included being ‘smitten on the head with a ruler and [having] one�
�s ears pulled ’til they bled’. As his contemporary biographers who knew him well put it, the effects of this harsh treatment remained ‘in a certain hesitation of manner and obliquity of reply which Maxwell was long in getting over, if, indeed, he ever quite got over them’.
In this difficult time, Maxwell’s release was the chance to roam free on the estate, observing the natural world close-up. This is something that his father had always encouraged, and Maxwell took a particular interest in the variations in colour he saw in nature. He was especially interested in crystals, which fascinated him in the way that their colours changed as they were put under pressure. His father’s friend, Hugh Blackburn, a professor from Glasgow University, added a novel delight, allowing Maxwell to help him launch a series of hot air balloons from the Glenlair estate.
Maxwell had the usual youngster’s excitement and interest in everything around him. According to the early biography, among his favourite phrases were ‘Show me how it doos’, and ‘What’s the go o’ that§?’ This enthusiastic curiosity about the world around us seems natural in youth – speak to children at primary school and you can’t miss the way that they are enthused by science – but many lose that sense of wonder during their secondary school years. Maxwell held on to a childlike fascination for the rest of his life.
The Academy
It was clear, though, that the attempt to use the failing tutor to deal with Maxwell’s education was a disaster that could not be sustained; Frances’ sister, Jane Cay, who lived in Edinburgh, came to the rescue. She suggested to John that Maxwell could come to live in the city with John’s unmarried sister Isabella. Isabella’s house was ideally placed to walk to the prestigious Edinburgh Academy – Maxwell could get a decent education and live under the supervision of his aunts during term time, then return to roam free on the Glenlair estate in the holidays. This wasn’t, however, a matter of his father dismissing Maxwell solely to his aunts’ care – in the winter particularly, John Clerk Maxwell spent regular evenings in Edinburgh with his son.
