A true pioneer in his own field

Published on Saturday 15 April 2006 00:07

IT IS one of the great anomalies of the celebration of Scottish genius that the achievements of James Clerk Maxwell have figured so marginally in that extraordinary panoply. Among professional scientists he is accorded a status comparable to that of Newton and Einstein. Peter Harman, the editor of Maxwell's letters and papers, has written: "James Clerk Maxwell's contributions to science... have established his special place (with Isaac Newton and Albert Einstein) in the history of physics."

We need only quote the words of Einstein himself to gauge Maxwell's significance: "We may say that, before Maxwell, Physical Reality, in so far as it was to represent the process of nature, was thought of as consisting in material particles... Since Maxwell's time, Physical Reality has been thought of as represented by continuous fields, governed by partial differential equations, and not capable of any mechanical interpretation. This change in the conception of Reality is the most profound and the most fruitful that physics has experienced since the time of Newton." On the walls of his study, Einstein hung pictures of Maxwell and Faraday.

Einstein's words also spell out one of the difficulties in appreciating Maxwell's genius. While everyone can appreciate Newton's achievements through being taught his laws of motion, for example, force equals mass times acceleration, there is no such simple mechanical picture which can be provided for the fields in physics. And yet, fields are absolutely central to the whole of modern physics. Freeman Dyson has written: "Instead of thinking of mechanical objects as primary and electromagnetic stresses as secondary consequences, you must think of the electromagnetic field as primary and mechanical forces as secondary. The idea that the primary constituents of the universe are fields did not come easily to the physicists of Maxwell's generation. Fields are an abstract concept, far removed from the familiar world of things and forces."

It is significant that the time when Maxwell made his great discoveries coincided with the period when it became essential to express the fundamental laws of physics in mathematical language which was beyond the comprehension of the common reader. While Faraday's understanding of the laws of electromagnetism was expressed in terms of images of the behaviour of magnetic field lines, the physical content of his discoveries needed the higher mathematics of fields to reveal their deeper content. It is not coincidental that the first chair of theoretical physics in Europe was established for Rudolf Clausius in the 1850s. This epoch can be regarded as the time when the nature of fundamental physics began to diverge from what could be readily comprehended by the interested lay person.

In addition to the problem of articulating exactly what Maxwell's contributions were in everyday terms, Maxwell himself was excessively modest about them. In his presidential address to the British Association for the Advancement of Science in 1870, he reviewed all the other theories but not his own, merely referring to: "Another theory of electromagnetism which I prefer." Again quoting Freeman Dyson, "the moral of this story is that modesty is not always a virtue".

But this is only one part of Maxwell's achievements, which span essentially the whole of physics. His contributions to thermodynamics and the foundations of statistical physics were equally profound. His discovery of what we now call the Maxwell distribution of velocities of the particles of a gas was a miracle of economy of expression and has profound implications for all the physical and biological sciences. For example, the very rare events which give rise to biological phenomena and the nuclear reactions which power the Sun are described precisely by the Maxwell distribution. Equally important, the discovery of this distribution had consequences for the fundamentals of thermodynamics and the direction of evolution of natural processes, as embodied in the second law of thermodynamics. Francis Everitt, Maxwell's biographer, rightly remarks that Maxwell's derivation of the Maxwell distribution marked the beginning of a new epoch in physics and is central to everything we do in science nowadays.

Fortunately, the tide is turning. The James Clerk Maxwell Foundation has made enormous efforts to raise an appreciation of Maxwell's genius. The Foundation's Education Centre at 14 India Street in Edinburgh, the house where Maxwell was born, contains a wonderful selection of material on Maxwell, his family and his contributions to science. The Royal Society of Edinburgh is developing plans to honour Maxwell's memory through the commissioning of a statute. There is still a great deal to do. It always saddens me that there is so little mention of Maxwell and his achievements in the great Scottish museums.

My own view is that it is now quite feasible to use modern methods of presentation to give an appreciation of the profundity of Maxwell's insights. We have developed simulations and presentational methods which illustrate beautifully many of Maxwell's contributions. It is not realistic to expect the lay person to understand the details of the origin of the Maxwell distribution or how the statistical interpretation of the laws of thermodynamics can be related to the law of increase in entropy in natural processes, but it can now be done by simulations which I presented last night at the Edinburgh Science Festival.

This year is the 175th anniversary of Maxwell's birth and there is no better time to begin the process of assimilating his achievements into the consciousness of all Scots and indeed everyone worldwide. By the time of the 200th anniversary, let us hope that Maxwell's memory will be as fixed in the Scottish and international imagination as those of Robert Burns, Walter Scott and the myriad of other great Scots.

• Malcolm Longair is a physicist and astronomer.

Spotlight shines on Maxwell's genius 175 years on through special events

JAMES Clerk Maxwell's genius may have gone largely uncelebrated, but this year the 175th anniversary of his birth will see several events designed to put this right.

The Royal Museum in Edinburgh plans to host two keynote lectures by Professor Graeme Ackland - one for schools and another for the general public - in June. And there is currently a small display about arguably Scotland's greatest scientist at the museum in the history of science gallery.

However while Maxwell is ranked alongside Isaac Newton and Albert Einstein, his work failed to capture the popular imagination in the same way.

And as he was largely a theorist, there are few actual physical artefacts left which are associated with him.

Tacye Phillipson, science curator at the National Museums of Scotland, said: "James Clerk Maxwell was one of the key theoretical thinkers of his time and a great experimental teacher who was constantly looking for the best way to teach graduates.

"As a brilliant ideas man with highly developed experimental skills, his greatest scientific contributions were theoretical, so his legacy is less associated with material objects than some of the other great scientists."

The two objects held by the museum are a three-dimensional plaster model of the thermodynamic surface of water - based on mathematical equations that describe how substances pass from a solid to liquid and then gaseous state - and a spinning top built to show the stability of rotating objects.

The lectures by Prof Ackland, of Edinburgh University, will be held on Tuesday, 20 June, in the Chambers Street lecture theatre. The talk for schools is at 11am and the public lecture starts at 6:30pm. Both are free but tickets are required.

Maxwell biographer Dr Basil Mahon will give four talks about the great man in Aberdeen, Dundee, Glasgow and Edinburgh later this month.

The first event at Aberdeen will be held on 25 April at 7:30pm in the Fraser Noble Building in Old Aberdeen, the second on 26 April at 7pm at Dundee University's Tower Extension lecture theatre, the third at Glasgow Science Centre on 27 April at 7:30pm, with the final talk in the James Clerk Maxwell Building in Edinburgh University's Kings Buildings on Friday, 28 April, at 7:30pm.

From 11 to 18 June, an exhibition about Maxwell will be held in Parton village hall, in Dumfries and Galloway near Glenlair, the scientist's family home, and the cemetery at Parton Kirk, where he is buried.

In the autumn of this year, the James Clerk Maxwell Centre will be opened at Edinburgh Academy, where Maxwell was a pupil. The centre is described as a "first-class new science facility".

Summing up Maxwell's contribution, the president of the Royal Society of Edinburgh, Sir Michael Atiyah, said: "After Isaac Newton, Maxwell was the greatest physicist that Britain has produced. He ranks with Einstein as one of the founders of modern physics.

"While Newton laid down the laws of mechanics, Maxwell produced the laws of electromagnetism. These underpin all of modern technology, from electric power to television and computers," Sir Michael said.

IAN JOHNSTON

SCIENCE CORRESPONDENT