William Thomson (later Lord Kelvin)

William Thomson (later Lord Kelvin) was arguably the most famous member of the department of Physics and Astronomy at the University of Glasgow. He was born on the 26 June 1824 in Belfast Ireland, and was part of a large family whose mother died when he was aged six. His father taught Kelvin and his brothers mathematics to a level beyond that of university courses of the time. Kelvin’s father accepted a post at the University of Glasgow in 1834. At the same time, Kelvin entered the University, aged 10, and had his first papers published at the ages of 16 and 17.

These papers contained an argument defending the work of Fourier (Fourier transforms), which at that time was being heavily criticized by British scientists. He showed that Fourier’s mathematics could be applied to other physical phenomena other than that of heat flow, where it was original applied. At the age of fifteen Kelvin wrote an essay which he called “An Essay on the Figure of Earth. ” Kelvin used this essay as a source and inspiration for ideas all of his life and won an award from the University.

In 1841 he entered the University of Cambridge, graduating with a B. A honors degree four years later. Kelvin then went on to Paris to carry out work in a laboratory in order to gain practical experience and competence in experimental work. At the age of only 22 Kelvin was elected to professor of physics (the ‘chair of natural philosophy’) as a result of a very well organized campaign run by his father, who was still a professor of mathematics. Kelvin remained at the University of Glasgow for the rest of his working life. He was a practical man, and on occasion during lectures on the conservation of momentum he would give a demonstration of this to his students.

At one end of the lecture room he would suspend a large block of wood like a pendulum and at the other he would have a gun. By firing the gun at the block of wood the bullet would become embedded in an unrealistic collision passing momentum to the combined block of wood and bullet. By measuring the amplitude of the oscillation, the momentum and speed of the bullet could be calculated. Needless to say, this experiment was eventually stopped for safety reasons, though no one was ever known to be injured. Kelvin first defined the absolute temperature scale in 1847, which was later named after him.

In 1851 he published the paper, “On the Dynamical Theory of Heat”, and in the same year was elected to the Royal Society. This work contained his ideas and version of the second law of thermodynamics as well as recognition of James Joule’s idea of the mechanical equivalent of heat. This idea claimed that heat and motion were combined, an idea that is now taken as second nature – where there’s motion there’s heat and vice versa, in some form or another – but at that time when Joule first introduced it, interconvertability pretty much cut across the grain of scientific belief.

At the time heat was thought to have been a fluid of some kind. Kelvin also maintained an interest in the age of the sun and calculated values for it. The assumption was that the sun produced its radiant energy from the gravitational potential of matter falling into the sun, including meteorites and even planets. In collaboration with Hermann Von Helmholtz, he calculated and published in 1853 a value of 50 million years. What he did not know at the time was the effect of the- as-yet-undiscovered radioactivity. He also made inquiries into the age of the earth, calculating a maximum of 400 million years.

These calculations were based on the rate of cooling of a globe of matter after first solidification occurs i. e. after the earth was first formed. Basing his ideas on these conclusions, he became an opponent of Darwin’s theory of evolution. Darwin knew from calculations of geologists, which were based on the rate of sedimentation, and the thickness of sedimentary rocks, that the earth had to be hundreds of millions of years old and that life could have evolved slowly to adapt to its environment over this time.

Kelvin did not accept Darwin’s theory because he claimed that the temperature of the sun and earth approximately a million years ago would have been too great to have supported life. Kelvin started work in 1854 on the project of laying transatlantic cables, having been asked the question on how long it took for electrical signals to traverse long cables. His idea was that electrical current flow was analogous to that of heat flow and, by applying ideas on heat flow, helped in the problem of transmitting electrical signals over long distances.

Kelvin became chief technical consultant for a transatlantic cable laying company, and it was reported that he risked his life on many occasions while supervising the laying of cables. Kelvin invented the mirror galvanometer which he patented in 1858 as a long distance telegraph receiver, and with a few modifications it later became the most widely used receiver in underwater cable networks. Other inventions by Kelvin include the flexible wire conductor or ‘flex,’ a law which calculated how much a cable costs in respect of electrical losses and a gyrocompass among a host of others.

The transatlantic cable laying expeditions made Kelvin an extremely wealthy man. Queen Victoria knighted Kelvin in 1866 for his work. In 1889 he retired from the university after having been professor there for 53 years. In the year 1890 he became the president of the Royal Society and held that position until 1895. He was created Baron Kelvin of Largrs in 1892 and in 1902 received the Order of Merit. After a long and fruitful career, publishing over many papers and being granted numerous patents Kelvin died at his home on the 17th of December, 1907, in his estate close to Largrs, Scotland. He is buried at Westminster Abbey, London.

