George Francis Fitzgerald – ‘our friend of brilliant ideas’

The life and work of George Francis Fitzgerald is celebrated in a short volume edited by Denis Weaire [1]. It contains five articles which were originally published in the European Review [2] that focus on his life, membership of a circle known as the Maxwellians, which included Fitzgerald, Oliver Lodge, Oliver Heaviside and others, his correspondence with Heinrich Hertz and his contributions to industry and technology.  The article on the Maxwellians by Bruce Hunt of the University of Texas is an abridged version of his book with that title [3].  This article draws on these references.

The story of the Maxwellians begins in 1878 when Oliver Lodge, then at University College London, came to Dublin for the meeting of the British Association for the Advancement of Science (BA) in August of that year and met Fitzgerald for the first time.  Both men were 27 years old and over more than two decades of friendship they formed a strong personal bond, eventually signing their letters to each other with their greek initials, f and L.  The Scottish physicist, James Clerk Maxwell at the University of Cambridge, had published his Treatise on Electricity and Magnetism in 1873, yet it would be many years before the theoretical and practical implications of this work would be appreciated by scientists and engineers.  Maxwell died in 1879 aged just 48, leaving it to others to explore his work.  Oliver Heaviside, just a year older than Fitzgerald and Lodge, was briefly a telegraph engineer in Newcastle.  He ‘retired’ at the age of 24 for health and personal reasons and spent the next 20 years living with his parents in London and Devon.  Heaviside worked in isolation on Maxwell’s equations, reformulating them in a way that is recognisible as the four vector equations which now bear Maxwell’s name.  Heaviside began to correspond with Fitzgerald and Lodge following the 1888 meeting of the BA in Bath. Heaviside was not present at the meeting. However, Lodge took one side in a controversy over the design of lightning conductors, a dispute which Heaviside was also involved in.  Since Heavside and Lodge were in agreement, they were natural allies.  According to Hunt [3], Heaviside and Lodge met in person only once and Heaviside and Fitzgerald, twice. Nevertheless, a regular correspondence with Heavside by post continued for many years. 

One of the most important issues of the day in physics was the possibility of generating electromagnetic waves.  In early 1888, Lodge was experimenting with sudden electrical discharges through conducting wires which set up electromagnetic waves around the wire and caused a faint glow in the air, enabling Lodge to measure the wavelength of the waves.  That summer, on holiday in the Alps, Lodge became aware of the work of Heinrich Hertz in Karlsruhe. By this time Hertz was able to generate electromagnetic waves in air, reflect them off walls as well as measuring their wavelength.  Fitzgerald was president of the BA at this time and he used his presidential address at the Bath meeting of the BA to draw attention to Hertz’s results.  By January 1889, Fitzgerald and his assistant, Frederick Trouton, had succeeded in reproducing Hertz’s observations in Dublin and correspondence between Fitzgerald and Hertz has been preserved [2]. 

Hertz had succeeded in demonstrating generation of electromagnetic waves with wavelengths of a few metres in air (radiowaves) by means of sudden electrical discharges. Electromagnetic waves with such long wavelengths were not as familar as light waves with wavelengths shorter than 1 mm.    In the late 19th century it was believed that all waves propagated in a medium – air for sound waves, water for water waves and ‘the ether’ for light waves.  In 1887 two American physicists, Alfred Michelson and Edward Morley had performed the famous Michelson-Morley optical interferometry experiment which was designed to detect the ether.  However, they had failed to observe the effect that they believed would demonstrate the presence of an ether. 

Inspired by some accounts of the BA meeting in Bath in September 1888, Heavside succeeded in deriving an expression for the electric field created by an electric charge in motion.  Compared to the spherically symmetric field created by an electric charge at rest, the field due to the charge in motion was reduced along the direction of motion by a factor, √(1-v2/c2), where v/c is the ratio of the speed of the charge to the speed of light.  A few days after receiving a letter from Heaviside on this topic, Fitzgerald, visting London, called to visit Heaviside on the 8th February 1889.

About two months later, Fitzgerald visited Lodge in Liverpool where they mulled over the results of the Michelson-Morley experiment.  This experiment and its principles are well known to undergraduate physicists.  It supposes that light propagates with a certain velocity with respect to the ether and that when an observer is in motion with respect to the ether, then the light velocity with respect to the observer will depend on that relative motion.  The experiment consists in splitting a light source into two beams in an apparatus which is in motion with respect to the ether. One beam is supposed to travel across the ether flow and back and the other upsteam and downstream in the ether.  The key expressions derived in the analysis of the experiment contain factors similar to the factor involving the ratio derived by Heaviside for the electric field strength created by an electric charge in motion.

According to Hunt [3], while in discussion with Lodge, Fitzgerald had the brilliant idea that the null result of the Michelson-Morley experiment could be explained by a contraction of the apparatus in its direction of motion in the ether, similar to the reduction in electric field strength along the direction of motion when an electric charge is in motion. In a letter to the relatively new American journal, Science, entitled, ‘The Ether and the Earth’s Atmosphere’ and dated 2nd May 1889, Fitzgerald wrote [4],

‘I have read with much interest Messrs. Michelson and Morley's wonderfully delicate experiment attempting to decide the important question as to how far the ether is carried along by the earth. ... I would suggest that almost the only hypothesis that can reconcile this opposition is that the length of material bodies changes, according as they are moving through the ether or across it, by an amount depending on the square of the ratio of their velocity to that of light. We know that electric forces are affected by the motion of the electrified bodies relative to the ether, and it seems a not improbable supposition that the molecular forces are affected by the motion, and that the size of a body alters consequently.’

This contraction in the length of a body in motion has become known as the Fitzgerald-Lorentz contraction.  The degree of contraction when the body is in motion at speed, v, is the Lorentz factor γ = 1 / √(1 – v2/c2), with its obvious connection to the factor found by Heaviside.  Independently, Hendrik Lorentz in Leiden came to the same conclusion and published a paper entitled, ‘The relative motion of the earth and the aether’ in 1892 [5].  This proposal gave the correct expression for contraction of bodies in relative motion predicted by Einstein’s special theory of relativity. It was based on the erroneous notion of interaction of matter with an ether. In 1904 Lorentz published his famous paper entitled, ‘Electromagnetic phenomena in a system moving with any velocity smaller than that of light’ [6] which contains the Lorentz transformation of special relativity.  The mathematical factor for the degree of contraction is the same Lorentz factor, but the accepted explanation is that the geometry of space-time and that light travels in free space at the same speed in all frames of reference. There is no need to invoke a medium such as the ether to explain the propagation of light in free space.

We have discussed the main events in Fitzgerald’s scientific life, however he also was much concerned with the applications of scientific discovery in industry.  David Attis’ contribution to the focus articles on Fitzgerald and the Maxwellians [2] is on Fitzgerald’s work in technology. With Hertz’ demonstration of generation of electromagnetic waves in air in 1888, telegraphy over transmission lines would soon be replaced by wireless telegraphy. Alexander Graham Bell had introduced the telephone in 1876. The Italian Gugliemo Marconi would come to England in 1896 seeking investment in his wireless communication experiments.  Marconi’s mother was Annie Jameson of the Irish whiskey distilling family and by 1898 Marconi had come to Ireland where he transmitted the world’s first live commentary on a sporting event at the Kingstown yacht race.  Marconi used equipment from Fitzgerald’s laboratory for the event. Marconi went on to quickly establish transatlantic wireless telegraphy between Cornwall in England and Newfoundland in Canada and Clifden and Ireland to Nova Scotia in Canada.

Otto Lilienthal had pioneered flight in his gliders near Berlin. Fitzgerald took an active interest in flight and purchased a glider from Lilienthal in 1895. His efforts at flying in College Park in Trinity are recorded in many photographs.

The latter half of the 19th century saw establishment of physical laboratories at leading universities in Britain, beginning with William Thomson’s (Lord Kelvin) laboratory at Glasgow University in the 1850’s. In 1899 the Board of Trinity College appointed a committee to look into introducing Electrical and Mechanical Engineering into the undergraduate engineering degree. This led to appointment of a further Science Committee. Fitzgerald sought a sum of £250,000, but the College’s annual income at that time amounted to just £80,000 and the Committee was asked to submit a more economical report. Tragically, Fitzgerald died on 22nd February 1901 aged just 49 while recovering from an operation on a stomach ulcer and did not live to see the completion of the Physical Laboratory.  Completion of the laboratory was left to John Joly and others, funded by  a donation by Lord Iveagh, chairman of Guinness brewery and completed in 1906.  The laboratory is now known as the Fitzgerald Building.

Hearing of Fitzgerald’s illness, Heavside had written to Lodge saying that he was, ‘grieved to hear of the illness of our friend of brilliant ideas’.  Afterwards, Heaviside wrote of Fitzgerald, ‘He had, undoubtedly, the quickest and most original brain of anybody.’  He continued, ‘That was a great distinction; but it was, I think, a misfortune as regards his scientific fame.  He saw too many openings. His brain was too fertile and inventive. I think it would have been better for him if he had been a little stupid – I mean not so quick and versatile, but more plodding. He would have been better appreciated, save by a few’.

[1] George Francis Fitzgerald, D. Weaire Ed. , Living Edition Publishers, Pőllauberg (2009)

[2] Focus: Fitzgerald and the Maxwellians, European Review 12 513-573 (2007)

[3] The Maxwellians, B. Hunt, Cornell University Press, Ithaca NY (1991)

[4] G. F. Fitzgerald, Science, 13, 390 (1889)

[5] H. Lorentz, Zittingsverlag Akad. V. Wet. 1, 74 (1892)