Denis Weaire remarked in the Dictionary of Irish Biography that Lord Kelvin, also known as Belfast-born William Thomson, had a profound influence in the field of physics for over fifty years. His pivotal contribution helped to shape physics as a standalone domain of study, earning him the reputation of being one of the last great classical physicists.
Thomson was born on June 26th in College Square East, to James Thomson, a headmaster, and Margaret Gardner. After his mother passed away in 1830, he was taught by his father from an early age. Their roots trace back to Scotland and the family relocated there once his father took up the professorship of mathematics at Glasgow University in 1831. William exhibited immense academic potential and by 1834, he had already enrolled at the university with his brother, James. Even at the tender age of 16, he advanced to Cambridge and his exemplary performance continued. His remarkable research in maths and theoretical physics won him the Smith’s Prize at Cambridge, prompting one of his examining panel to famously jest that they were only competent enough to mend his pens.
After spending a year as a Peterhouse College, Cambridge, fellow, along with a stint in Paris where he had studied French previously, he earned the position of Professor of Natural Philosophy at Glasgow University at the age of 22. He taught in the same place where he was once a fresher.
Despite tempting offers from various prestigious establishments, he maintained his professorship for 52 years. Denis Weaire suggests that Lord Kelvin considered staying away from the draining centres of power and bureaucracy in the south to be beneficial.
While the scope of this text doesn’t allow a comprehensive review of his scientific accolades, it’s worth noting that Lord Kelvin’s inquisitive mind is evident in his extensive collection of notebooks, now preserved at the Cambridge University Library. He threw himself into a broad spectrum of research. As per Denis Weire’s estimation, he authored over 650 papers covering an array of topics from optics, elasticity, electricity, magnetism, thermodynamics, hydrodynamics, navigation, geophysics, crystallography, metrology to telegraphy.
He put forth the concept of an absolute temperatures scale, denoted in “kelvin units”, a result of his evaluative work. This man was responsible for determining the precise value of the hitherto known absolute zero – the chilliest possible temperature. The “Joule-Thomson effect”, a phenomenon describing temperature alteration of a real gas or liquid in thermodynamics, bears his name. He additionally shares attribution for the fundamental concept of entropy in thermodynamic theory.
Amongst his credited inventions features air cooling through refrigeration, one of several patents he secured.
In the realm of undersea telegraphy, he achieved substantial commercial success. When the premier attempt at implementing a transatlantic cable faltered, the backers of the venture accepted his proposed enhancements. His primary contribution was utilising a mirror galvanometer, a device indicating detection of an electric current by redirecting a light beam with a mirror, which he personally engineered. This triumph paved the way for his contribution to the installation of the French Atlantic cable in 1869 and Brazilian cables in 1883. His resolution of these and additional challenges showcased his mathematical expertise, profound comprehension of material properties, and practical abilities; “his extensive examination of materials established one of the bedrocks of contemporary solid-state physics,” as noted by Denis Weaire, who highlighted that many terms he coined, such as “permeability”, “susceptibility” and “bulk modus”, are still in use.
However, according to Weaire, one of his few deficiencies as a physicist was his unwillingness to embrace the electromagnetic theory of light proposed by James Clerk Maxwell. Weaire argued that this failing was more significant than his widely cited misestimation of the Earth’s age. Thomson gauged the Earth to be between 20 million and 40 million years old, considerably less than the currently accepted 4.54 billion, but subsequent discoveries made after his death significantly enhanced the accuracy of this calculation.
In 1856, he was named a Fellow of the Royal Society and was knighted a decade later. He received the renowned Copley Medal in 1883 and ascended to the peerage as Lord Kelvin in 1892. From 1890 to 1895, he served as president of the Royal Society. He was also the recipient of numerous foreign academic distinctions.
He never dismissed his Irish roots and was a staunch adversary of Home Rule. After his first wife’s death in 1879, he wed his second spouse, Frances Anna, in 1874, but neither matrimony bore any children. In his later years, he resided in his sizeable mansion constructed along the Ayrshire seashore, enjoying sailing on his yacht. On the 17th of December 1907, he passed away and found his final resting place near Isaac Newton, in Westminster Abbey, with dignitaries from across the globe in attendance at his funeral. His legacy is preserved through a museum in Glasgow dedicated to him, a multitude of portraits showcased in both Cambridge and Glasgow, and a monument erected in the Botanic Gardens of Belfast, facing his native place.