MAXWELL AND TAITScientists of Last Century
Dr W H M'Crea delivered a lecture "James Clerk Maxwell and Peter Guthrie Tait" to the Edinburgh Mathematical Society in the Mathematical Institute, Edinburgh University yesterday. Dr A C Aitken, the president, in the chair.
James Clerk Maxwell and Peter Guthrie Tait, said Dr M'Crea, took a prominent place among the scientists of last century. It was particularly fitting that their memory should be honoured by Edinburgh, to which they both belonged by birth and upbringing. They were, together at the Edinburgh Academy, and both later had distinguished careers at the Universities of Edinburgh and Cambridge. They remained the closest of friends each taking the keenest interest in the achievements of the other. The Edinburgh Mathematical Society took special pride in the memory of Tait. He was one of its very first honorary members and contributed notes on many branches of mathematics to its proceedings.
After holding professorships at Aberdeen and London, Maxwell became the first occupant of the Cavendish Chair of Experimental Physics at Cambridge. He brought great distinction to that office, and laid the foundation of the now world-wide fame of the Cavendish laboratory. His work in elucidating the fundamental processes of physical universe was regarded as second only to that of Newton. Most important of all was his work on the equations of the electro-magnetic waves which showed the electro-magnetic nature of light and ultimately led Hertz to the discovery of wireless waves.
At the age of 23, Tait was made Professor of Mathematics at Belfast. In 1860 he was elected to the Chair of Natural Philosophy in Edinburgh. He held this with outstanding distinction for thirty years. He was unsurpassed as a lecturer, and his classes attracted unusual attention. He reached a still wider public through his numerous books, his greatest service in this direction being the production in collaboration with Sir W Thomson (Lord Kelvin) of Thomson and Tait's "Natural Philosophy." This work brought about a revolution in the teaching of mechanics in Great Britain.
It was impossible in a lecture to give a catalogue of the achievements of Maxwell and Tait. It was better to try to say something about their work in one particular field. They both made contributions of first-class importance to the Kinetic theory of gases. This theory starts from the hypothesis that a gas consists of molecules in motion and deduces the gas laws. Maxwell showed how the energy is shared out among the molecules, and Tait gave a revised proof of his result. This result, when modified by the requirements of the quantum theory, had important consequences in astrophysics and also in the theory of metals. Tait showed that the free path of a gas molecule depends on its velocity. This conception is used in the problem of the retention of atmospheres by planets and helps to explain why the earth does not lose its atmosphere. Men considered the "time of relaxation" of a system, that is the time it takes to attain statistical equilibrium. The same idea has been applied by Jeans to the stars of the galactic system, and calculates for them a lifetime of about a million million years. The question of this time scale is at the root of the major problems of cosmic physics. These examples witness to the fact that the investigations of Maxwell and Tait continue to bear fruit in the fundamental problems of the physical universe.
Guests at yesterday's meeting were Bishop Reid of Edinburgh and Mrs Reid, and Mr J C Tait and Miss Tait. Others present were:- Prof E T Whittaker. F.R.S., and Mrs Whittaker, E M Horsburgh and Dr E Lindsay Ince, Edinburgh University; Dr W 0 Kermack. Royal College of Physicians, Edinburgh; Professor D M Y Sommerville. New Zealand; Professor H W Turnbull, St Andrews University, and Mrs Turnbull; Dr E T Copson. St Andrews University; Dr R A Robb and Dr Gillespie. Glasgow University: Mr J A Macdonald, H.M.I., Peebles; and Mr H F Rose and Mr Andrew Young, Edinburgh. At the conclusion of the lecture, Mr J C Tait, who is a son of Professor Tait, read letters and other documents which passed between Maxwell and Tait.