Professor Maxwell's Duplicitous Demon

by Brian Clegg

  Three weeks after his father’s death, Maxwell wrote to his friend Lewis Campbell:

  When the term is over I must go home and pay diligent attention to everything there, so that I may learn what to do. The first thing I must do is carry on my father’s work of personally superintending everything at home, and for doing this I have his regular accounts of what used to be done, and the memories of all the people, who tell me everything they know.

  It was not taken for granted, then, that Maxwell would continue his academic work, but in the same letter he made it clear that his father had felt that Maxwell could achieve the appropriate balance.

  As for my own pursuits, it was my father’s wish, and it is mine, that I should go on with them. We used to settle that what I ought to be engaged in was some occupation of teaching, admitting of long vacations for being at home; and when my father heard of the Aberdeen proposition he very much approved. I have not heard anything very lately, but I believe my name is not yet out of the question in the Ld Advocate’s book.

  Maxwell was correct – his name was at the top of the list and he was duly awarded the position. He would spend the remainder of the term at Cambridge and the long summer vacation putting things in order at Glenlair. He found time in that vacation to undertake some work on colour and on Saturn’s rings (more on this later), but there is no doubt that the responsibilities he had inherited from his father came first.

  In a letter to a university friend, Richard Litchfield, he noted:

  I have certainly no time now & I have much more occupation than I expected such as to examine into the state of two sets of houses & provide wood &c for roofing them and workmen to do it and various things of this kind also to enquire into the merits of the younger clergy and the sentiments of the parish on the subject, for our minister died unexpectedly this week and there are no resident proprietors in the parish except the patron of the living who is a lady of Romish persuasion [i.e. Catholic] who has been for a year in Edinburgh and denies herself to all her friends.

  Despite the unexpected workload, Maxwell was able to bring Glenlair under his control and made the move to Aberdeen in the autumn.

  Notes

  1 – John Clerk Maxwell’s list of suggested places for his son to visit in Birmingham is noted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 3.

  2 – Maxwell’s observations on Cambridge colleges before applying, noted by Mrs Morrison, are recorded in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 132.

  3 – Maxwell’s experiment with working during the night was in a letter to Lewis Campbell dated 11 March 1851, written from his lodgings in King’s Parade, Cambridge, quoted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 155.

  4 – Lewis Campbell’s note that Maxwell ironically engaged with electro-biology and table-turning is from Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 166.

  5 – John Clerk Maxwell’s letter to his son on the dangers of electro-biology is quoted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 156.

  6 – Maxwell’s concern on the way Faraday was treated after explaining the phenomenon of table-turning is from a letter to the Reverend C.B. Tayler, written from Trinity College, Cambridge on 8 July 1853, quoted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 189.

  7 – Lewis Campbell’s description of Maxwell’s appearance while at Cambridge is from Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 162.

  8 – Maxwell’s letter to his wife from Trinity College, Cambridge, written on 4 January 1870, is quoted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 499.

  9 – Maxwell’s poem ‘A Vision’ is reproduced in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 632.

  10 – Maxwell’s letter to his aunt, Miss Cay, on using his instrument to see into eyes, particularly of dogs, from Trinity College, dated Whitsun Eve, 1854, is quoted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 208.

  11– Maxwell’s manuscript on the colour top is ‘Description of the Chromatic Teetotum as Constructed by Mr J.M. Bryson, Optician Edinburgh’, from 27 February 1855, reproduced in Peter Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell, Vol. 1 (Cambridge: Cambridge University Press, 1990) pp. 284–6.

  12 – Maxwell’s paper ‘Experiments on Colour as Perceived by the Eye, with Remarks on Colour-Blindness’, based on his initial colour top work, was published in Trans. Roy. Soc. Edinb., 21 (1855): 275–98 and its abstract is reproduced in Peter Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell, Vol. 1 (Cambridge: Cambridge University Press, 1990) pp. 287–9.

  13 – Maxwell’s letter to William Thomson which mentions the difficulties of reproducing brown colours was written from Trinity College on 15 May 1855 and is reproduced in Peter Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell, Vol. 1 (Cambridge: Cambridge University Press, 1990) pp. 305–13.

  14 – Maxwell’s letter to Monro on colour theory, written from Glenlair on 6 July 1870, is quoted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 346.

  15 – Maxwell’s description of his fluid model of electromagnetism as not containing the shadow of a theory is from Peter Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell, Vol. 1 (Cambridge: Cambridge University Press, 1990), p. 207.

  16 – Maxwell’s letter to his father about getting shops to shut early for the Working Men’s College was written from Trinity College, Cambridge on 12 March 1856 and is reproduced in Peter Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell, Vol. 1 (Cambridge: Cambridge University Press, 1990), p. 404.

  17 – Cecil Monro’s letter on translating Newton, dated 20 January 1855, and Maxwell’s reply from 18 India Street, Edinburgh, dated 7 February 1855, are reproduced in Peter Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell, Vol. 1 (Cambridge: Cambridge University Press, 1990), p. 280.

  18 – Professor Forbes’ letter to Maxwell recommending he consider the position at Marischal College is quoted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 250.

  19 – Maxwell’s letter to his father about applying for the position at Marischal, written at Trinity College, Cambridge on 15 February 1856, is quoted in Lewis Campbell and William Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 251.

  20 – Maxwell’s letter to Lewis Campbell about his responsibilities after his father’s death was written from Trinity College, Cambridge on 22 April 1856 and is reproduced in Peter Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell, Vol. 1 (Cambridge: Cambridge University Press, 1990), p. 405.

  21 – Maxwell’s letter to Richard Litchfield about his unexpected workload at Glenlair was written from Glenlair on 4 July 1856 and is reproduced in Peter Harman (ed.), The Scientific Letters and Papers of James Clerk Maxwell, Vol. 1 (Cambridge: Cambridge University Press, 1990), p. 410.

  * John Clerk Maxwell was a great enthusiast for the importance of visiting places as a means of self-improvement. When Maxwell was getting near to his final exams at Cambridge and suggested a few days’ break over the vacation to visit a friend in Birmingham, John wrote to him with a list of suggested venues his son could take in. These included ‘armourers, gunmaking and gunproving—swordmaking and proving—Papier-mâchée and japanning—silver-plating by cementation and rolling—ditto, electrotype—Elkington’s works—Brazier’s works, by founding and by striking out in dies—turning—spinning teapot bod
ies in white metal, etc.—making buttons of sorts, steel pens, needles, pins, and any sorts of small articles which are curiously done by subdivision of labour and by ingenious tools—glass of sorts is among the works of the place, and all kinds of foundry works—engine-making—tools and instruments—optical and [philosophical], both coarse and fine.’ Ever the attentive son, Maxwell began with the glassworks.

  † It was, and to some extent still is the fashion to refer to going ‘up’ to Cambridge from any point of the compass, but from Maxwell’s youthful viewpoint where all of England was in the south, it surely was ‘down’.

  ‡ Hidden.

  § Cambridge rooms had (and older ones still do have) an odd contrivance of inner and outer doors with only an inch or so between them. The inner door was the ‘oak’ and the outer door the ‘sporting door’, closed to indicate that the occupant did not want to be disturbed – having a shut sporting door was referred to as ‘sporting the oak’.

  ¶ ‘Tripos’, pronounced ‘tri-poss’ rather than ‘tri-pose’, is the unique Cambridge system describing the exams necessary to gain a degree in a particular discipline. The word is said to come from the name of the three-legged stool that was used during oral examination, though there is limited evidence for this. Despite the ‘s’ on the end, it’s singular.

  || Another Second Wrangler was Maxwell’s somewhat older friend, the University of Glasgow physics professor William Thomson. Thomson had apparently been so obviously the favourite for Senior Wrangler that he didn’t bother to check the result, instead sending a college servant along to the Senate House where the results were posted to see whom he should commiserate with for being Second Wrangler. The servant returned to say, ‘You, sir.’

  ** University members were forbidden from attending the fair and would have been at risk of being arrested by the university’s proctors, so the fair was cunningly sited just outside the limits of their authority, on Stourbridge Common.

  †† Even here, the artists got it wrong with their ‘primaries’. The primary pigments are cyan, yellow and magenta (take a look at the inks in your colour printer) – the blue, yellow and red colours that we still teach at school are just approximations to these. But, as we demons know all too well, you can’t expect reliability from artists.

  ‡‡ It would be wrong to criticise in retrospect the fact that the Working Men’s College was aimed at men only. Maxwell was a man of his time and gave limited consideration at this point in his career to women’s education.

  §§ This was Joseph Butler’s book The Analogy of Religion, Natural and Revealed, to the Constitution and Course of Nature – which was anything but a mathematical title.

  ¶¶ The Lord Advocate was the senior legal and political role in Scotland, a position at the time held by a James Moncrieff.

  |||| Nor was he as precocious as the Swiss mathematician Leonhard Euler, who became a professor at St Petersburg aged nineteen.

  Demonic Interlude III

  In which atoms become real and heat gets moving

  It’s arguable that the summer of 1856 was when JCM made the transition from a youth to a man. His career had made the leap from graduate student to professor, he lost his father – with whom he had been very close – became the laird of Glenlair, and had moved from a city where his intellect was a comfortable fit to a more remote location where he would stand out more than most.

  As Aberdeen is going to be the location where our young professor starts to take on the matters that will bring me into being, it’s important we get a little background on the matter of atoms (and molecules), and of heat.

  Atoms exist

  At the heart of JCM’s thinking on thermodynamics and the mechanics of gases was the idea that atoms and molecules were real. This is such a trivial point today that it’s worth emphasising that in the 1850s the majority of scientists were at best ambivalent as to the existence of atoms. They were considered a useful concept for explaining the way elements combined in chemistry, but were thought probably not to be actual physical things. Yet it was their reality that spurred on the thinking that would be JCM’s biggest claim to fame in his own era.

  Back in the fifth century BC, the Ancient Greek philosopher Democritus dreamed up the concept of atoms.* It seems quite a reasonable idea. If you cut stuff up, you get smaller and smaller pieces of that stuff. Eventually, Democritus argued, you’d get a piece that was so small that it was impossible to cut it any further. This was not because your knife wasn’t sharp enough, but because there was nothing more to divide. He called such a piece uncuttable: atomos.

  While there was a degree of logic to the thinking, the trouble was that as a scientific theory it didn’t have a lot of value because it didn’t explain anything. Democritus did not combine his concept of atoms with any idea of elements, which would have made it possible to simplify the description of matter. But a competitor, Empedocles, did come up with a theory of four elements: earth, air, fire and water. Though wrong, this had more practicality than the early atomic theory and was built on by one of the great philosophers: Aristotle.

  Active in the fourth century BC, Aristotle brought in a fifth element, the quintessence, which was the substance from which everything from the Moon outwards was supposed to be made. In principle, there was nothing to stop Aristotle from combining his elements with the atomic theory. Unfortunately, though, he had an aversion for totally empty space. He did not like the concept of a vacuum or void.

  The logic behind this aversion was sometimes convoluted, but the simplest argument Aristotle made, ironically to modern eyes, was that if there were a void, then something like Newton’s first law of motion would apply – there was no reason why anything moving should stop unless something forced it to do so. As this didn’t seem to happen in the nature he observed, Aristotle thought that the concept was flawed and so a void could not exist.

  Without a void or vacuum there couldn’t really be atoms, as the atoms would have to fit together in such a way that they totally filled empty space – something that was only possible with a very small number of shapes, such as a cube. Assuming that at the very least you needed four or five different types of atom, it simply seemed impossible to have atoms without space in between them. And Aristotle (with the stubbornness that is typical of some of you humans) wouldn’t allow it.

  Aristotle’s views were largely accepted unchallenged through to Galileo’s time, and it took a considerable period longer before atoms would be taken seriously. It was only really in the 1800s that atoms began to take hold as a realistic scientific concept. This was largely due to the work of John Dalton, an English Quaker who spent much of his working life in Manchester. Dalton was largely self-educated, unable to attend university because of his religious beliefs, as attendance at the time required membership of the Anglican Church.

  Apparently as a result of experiments on gases, right at the start of the nineteenth century, Dalton devised the concept of atom-based elements, where each of the spherical atoms of any particular element had the same weight. As early as 1803 he was beginning to note down the relative weights of these atoms, starting with the lightest, hydrogen. He also considered that many substances were compounds, made up not of individual atoms, but molecules which combined two or more atoms.

  There were limits to Dalton’s work. His equipment was mostly self-made and of poor quality even by the standards of the day. He got some of the relative weights wrong and made the mistake of assuming that compounds would be made up of the simplest possible combinations – so he thought, for example, that water was HO with a single hydrogen atom, rather than the pair of hydrogens present in the familiar H2O.

  He also had a mental model of atoms as spheres of different sizes, which seems to have prevented him from noticing the now-obvious implication that if ‘bigger’ atoms had multiples of the weight of hydrogen, perhaps they were made up of multiple hydrogen atoms (or the same subatomic particles as we now know). It didn’t help that, though Dalton often wrote the relat
ive weights of his elements as round numbers, he did not think these were exact values, but rather considered them to be convenient approximations.

  Again, with 20:20 hindsight it may seem that the concept of atom-based elements was so obvious that atoms should have been widely accepted by the time JCM started thinking about them. However, the general feeling was that they provided a useful model, but did not necessarily reflect any actual structure within a substance, just as JCM didn’t think that electricity was a fluid but found it a useful analogy. Matter’s behaviour could be well described as if it were a collection of atoms, but that didn’t mean they were real things you could pick up with tweezers and look at.

  It wouldn’t be until after 1905 – when Albert Einstein, in one of his first great papers, showed that calculations of the size of molecules could be made – that the reality of atoms was increasingly considered mainstream. It’s notable that when JCM’s friend Peter Tait was writing a textbook with William Thomson, Tait ruefully commented to a friend: ‘Thomson is dead against the existence of atoms; I though not a violent partisan yet find them useful in explanation.’ Yet a handful of scientists in the mid-nineteenth century made the assumption that atoms and molecules were indeed real – JCM among them.

  A better model of heat

  The reason for JCM’s interest in the atomic was not so much to consider the nature of matter directly, but rather to deal with a pressing problem of the day – how to explain the workings of heat. For thousands of years, the only real interest in heat was whether or not it was warm enough to be comfortable or a fire was hot enough to cook food.† But the nineteenth century saw the steam engine become the dominant power source for industry and travel. Steam was king – but understanding the true workings of the steam engine required the development of a new branch of physics – thermodynamics – and JCM would be at the heart of this work.