William Thomson, 1st Baron Kelvin (26 June 1824 – 17 December 1907), was a British mathematician, physicist, and engineer.

He was born in Belfast and served as the professor of Natural Philosophy at the University of Glasgow for 53 years. During this time, he conducted important research on the study of electricity. He helped create the first and second laws of thermodynamics and played a key role in combining different areas of physics, which was a new field of study at the time. He received the Royal Society’s Copley Medal in 1883 and was its president from 1890 to 1895. In 1892, he became the first scientist to be made a member of the House of Lords.

Temperatures measured in kelvin honor Lord Kelvin. Although scientists knew about the coldest possible temperature, called absolute zero, before his work, Kelvin calculated its exact value as approximately −273.15 degrees Celsius or −459.67 degrees Fahrenheit. The Joule–Thomson effect is also named after him.

Kelvin worked closely with Hugh Blackburn, a mathematics professor. He also worked as an electrical telegraph engineer and inventor, which made him well-known and earned him wealth and honors. For his role in the transatlantic telegraph project, Queen Victoria knighted him in 1866, giving him the title Sir William Thomson. He had strong interests in maritime technology and improved the mariner’s compass, which had previously been unreliable.

Kelvin was made a baron in 1892 for his achievements in thermodynamics and his opposition to Irish Home Rule. His title, Baron Kelvin of Largs, refers to the River Kelvin near his laboratory at the University of Glasgow. Despite offers from other universities, he stayed in Glasgow until his retirement in 1899. He continued working in industrial research and joined Kodak Limited as vice-chairman of its board in 1899. In 1904, he became Chancellor of the University of Glasgow.

Kelvin lived in Netherhall, a mansion in Largs that he built in the 1870s. He died there in 1907. The Hunterian Museum at the University of Glasgow has a permanent display about his work, including his original papers, tools, and other items, such as his smoking pipe.

Early life and work

William Thomson was born on June 26, 1824, in Belfast. His father, James Thomson, was a teacher of mathematics and engineering at the Royal Belfast Academical Institution. James was the son of an Ulster Scots farmer. James Thomson married Margaret Gardner in 1817. Of their children, four boys and two girls survived infancy. Margaret Thomson died in 1830 when William was six years old.

William and his older brother James were taught at home by their father, while the younger boys were taught by their older sisters. James was expected to receive most of his father’s support and encouragement, preparing him for a career in engineering.

In 1832, James Thomson was appointed a professor of mathematics at the University of Glasgow. The family moved there in October 1833. The Thomson children experienced a more international lifestyle than their father’s rural upbringing. They spent part of 1839 in London, and the boys studied French in Paris. Much of Thomson’s life during the 1840s was spent in Germany and the Netherlands. Learning languages was a top priority.

Thomson’s sister, Anna Thomson, was the mother of the physicist James Thomson Bottomley.

Thomson attended the Royal Belfast Academical Institution, where his father was a professor of mathematics. In 1834, at age 10, he began studying at the University of Glasgow. This was not because he was unusually advanced, but because the university had facilities for young students. He showed interest in both the classics and the sciences. At age 12, he won a prize for translating a work by Lucian of Samosata from Ancient Greek to English.

In the academic year 1839/1840, Thomson won a class prize in astronomy for his essay titled "Essay on the figure of the Earth." The essay showed his early skill in mathematical analysis and creativity. His physics tutor at this time was a man named David Thomson. Throughout his life, he returned to the ideas in this essay during difficult times. On the essay’s title page, he wrote lines from Alexander Pope’s "An Essay on Man." These lines inspired him to use science to understand the natural world.

Thomson became interested in Joseph Fourier’s work, "The Analytical Theory of Heat." He decided to study advanced mathematics, even though British scientists were still influenced by the ideas of Sir Isaac Newton. Fourier’s work had been criticized by some British mathematicians, including Philip Kelland, who wrote a book against it. This book encouraged Thomson to write his first scientific paper under the name P.Q.R., defending Fourier. His father submitted the paper to The Cambridge Mathematical Journal. A second P.Q.R. paper followed soon after.

In 1841, while on vacation with his family in Lamlash, Thomson wrote a third P.Q.R. paper titled "On the uniform motion of heat in homogeneous solid bodies, and its connection with the mathematical theory of electricity." In this paper, he connected the mathematics of heat conduction with electrostatics. James Clerk Maxwell later called this connection one of the most valuable scientific ideas.

William’s father provided generous support for his education. In 1841, he sent Thomson to Peterhouse, Cambridge, with letters of introduction and good living conditions. At Cambridge, Thomson participated in sports, athletics, and sculling, winning the Colquhoun Sculls in 1843. He was interested in classics, music, and literature, but his greatest passion was science. He studied mathematics, physics, and especially electricity. Under the guidance of William Hopkins, Thomson graduated in 1845 as second wrangler. He also won the first Smith’s Prize, which tests original research. Robert Leslie Ellis, one of the examiners, reportedly said to another examiner, "You and I are just about fit to mend his pens." He was the fourth person to receive The William Hopkins Prize (1876), awarded by the Cambridge Philosophical Society for invention or discovery.

In 1845, Thomson developed the first mathematical explanation of Michael Faraday’s idea that electric induction happens through a medium, or "dielectric," rather than through "action at a distance." He also created the mathematical method of electrical images, which helped solve problems in electrostatics, the study of forces between charged objects at rest. His work encouraged Faraday to conduct research in September 1845, leading to the discovery of the Faraday effect, which showed that light and magnetic (and thus electric) phenomena are related.

Thomson was elected a fellow of St Peter’s (as Peterhouse was often called) in June 1845. After gaining the fellowship, he spent time in the laboratory of Henri Victor Regnault in Paris. In 1846, he was appointed to the chair of natural philosophy at the University of Glasgow. At age 22, he became a professor at one of the oldest universities in the country, teaching students who had once been his classmates.

By 1847, Thomson was already known as a talented and unconventional scientist. At the British Association for the Advancement of Science meeting in Oxford, he heard James Prescott Joule argue that heat and mechanical work could be converted into each other. Thomson was interested but unsure. He believed the theories of Sadi Carnot and Émile Clapeyron, who studied heat engines. He predicted that the melting point of ice would decrease with pressure, otherwise ice’s expansion when freezing could be used to create a perpetual motion machine. Experiments in his laboratory supported his ideas.

In 1848, Thomson expanded the Carnot–Clapeyron theory by proposing an absolute temperature scale. He described a scale where "a unit of heat moving from a body at temperature T° to a body at temperature (T − 1)° would produce the same mechanical effect, no matter what T is." This scale would be independent of any specific substance. Thomson imagined a point where no heat could be transferred, the absolute zero, a concept first suggested by Guillaume Amontons in 1702. Carnot’s 1824 paper estimated absolute zero as −267°. Thomson used data from Regnault to calibrate his scale.

In his publication, Thomson wrote:

—But a footnote noted his first doubts about the caloric theory, referencing Joule’s discoveries. Surprisingly, Thomson did not send Joule a copy of his paper. When Joule eventually read it, he wrote to Thomson on October 6, saying his studies showed heat could be converted into work and that he planned further research.

Transatlantic cable

Though well-known in the academic field, Thomson was not well-known to the general public. In September 1852, he married Margaret Crum, the daughter of Walter Crum. However, her health worsened during their honeymoon, and for the next 17 years, Thomson focused much of his attention on caring for her. On 16 October 1854, George Gabriel Stokes wrote to Thomson to ask for his opinion on experiments by Faraday about the proposed transatlantic telegraph cable.

Faraday had shown how the design of a cable would affect how quickly messages could be sent. Thomson quickly responded to the challenge and shared his findings that month. He explained how the cable’s design could influence the speed of messages and the money that could be earned from the project. In a later analysis in 1855, Thomson emphasized how the cable’s design would affect its financial success.

Thomson argued that the speed of signals through a cable was related to the square of the cable’s length. His findings were questioned in 1856 by Wildman Whitehouse, an electrician for the Atlantic Telegraph Company. Whitehouse may have misunderstood his own experiments, but he was under pressure because the cable project was already underway. He claimed Thomson’s calculations meant the cable should be abandoned as impossible to complete.

Thomson challenged Whitehouse’s claims in a letter to a popular magazine, which brought him into the public eye. He suggested using a larger conductor with more insulation. He believed Whitehouse had the skills to make the existing design work. Thomson’s work caught the attention of the project’s leaders, and in December 1856, he was elected to the board of directors of the Atlantic Telegraph Company.

Thomson became the scientific adviser to a team with Whitehouse as chief electrician and Sir Charles Tilston Bright as chief engineer. However, Whitehouse influenced the cable’s specifications, supported by Faraday and Samuel Morse.

Thomson traveled on the cable-laying ship HMS Agamemnon in August 1857, while Whitehouse stayed on land due to illness. The voyage ended after 380 miles when the cable broke. Thomson shared his theory about the stresses involved in laying a submarine cable in a publication, explaining how a cable sinks in a slanted or straight path as it is laid.

Thomson developed a system for sending messages through a submarine telegraph, capable of sending one character every 3.5 seconds. He patented key parts of his system, the mirror galvanometer and the siphon recorder, in 1858. Whitehouse ignored many of Thomson’s suggestions until Thomson convinced the board that using purer copper would improve the cable’s performance.

The board required Thomson to join the 1858 cable-laying expedition without pay and take an active role. In return, Thomson got a chance to test his mirror galvanometer alongside Whitehouse’s equipment. Thomson found the conditions unsatisfactory, and the ship had to return home after a storm in June 1858. In London, the board considered abandoning the project but Thomson, Cyrus W. Field, and Curtis Lampson argued for another attempt. Thomson insisted the technical issues could be solved. During the voyages, Thomson gained practical skills and often led efforts during emergencies. A cable was completed on 5 August.

Thomson’s concerns were proven correct when Whitehouse’s equipment failed and had to be replaced with Thomson’s mirror galvanometer. Whitehouse claimed his own equipment was responsible for the service and took desperate steps to fix problems, which damaged the cable. When the cable failed completely, Whitehouse was dismissed, though Thomson objected and was reprimanded by the board. Thomson later regretted not challenging Whitehouse more strongly.

A committee was formed to investigate the cable’s failure, and most blame was placed on Whitehouse. The committee noted that while underwater cables were unreliable, most problems could have been avoided. Thomson was part of a group that recommended a new cable design, reporting in October 1863.

In July 1865, Thomson sailed on the SS Great Eastern for a cable-laying expedition, but technical problems caused the cable to be lost after 1,200 miles. The project was abandoned. A new attempt in 1866 successfully laid a new cable and recovered the 1865 cable. The project was celebrated as a success, and Thomson received public praise. He was knighted on 10 November 1866. Thomson partnered with C. F. Varley and Fleeming Jenkin to use his inventions for long submarine cables. He also created an automatic curb sender, a type of telegraph key.

Thomson participated in laying the French Atlantic submarine cable in 1869 and worked on other cables with Jenkin, assisted by Alfred Ewing. He was present during the laying of a section of the Brazilian coast cables in 1873.

Thomson’s wife, Margaret, died on 17 June 1870, and he decided to change his life. Already fond of the sea, he bought a schooner named Lalla Rookh in September 1870 and used it as a base for gatherings. In 1871, he joined an inquiry into the sinking of HMS Captain.

In June 1873, Thomson and Jenkin were on the Hooper when a cable fault caused a 16-day stop in Madeira. Thomson became close to Charles R. Blandy and his daughters. On 2 May 1874, Thomson sailed to Madeira on the Lalla Rookh and signaled to the Blandy home, “Will you marry me?” Fanny, Blandy’s daughter, responded, “Yes.” Thomson married Fanny on 24 June 1874.

Other contributions

From 1855 to 1867, Thomson worked with Peter Guthrie Tait to write a textbook that helped start the study of mechanics by focusing on the math of motion, without considering force. The book explained how energy connects different areas of motion. A second version came out in 1879 and was split into two separate parts. This textbook became a standard for teaching mathematical physics early on.

Thomson studied atmospheric electricity for a short time around 1859. He created tools to measure the electric field in the air, using some of the same devices he had made for telegraph work. He tested these tools in Glasgow and on the island of Arran. His measurements on Arran were so accurate they helped scientists understand air pollution near Glasgow. One of his tools, the water dropper electrometer, was used for many years at observatories like Kew and Eskdalemuir. It was still working at the Kakioka Observatory in Japan until 2021. Thomson might have noticed effects from the Carrington Event, a major storm in space, in September 1859.

Between 1870 and 1890, the vortex atom theory was popular in Britain. This idea said atoms were like swirling patterns in a substance called the aether. Thomson started this theory, which was different from an older idea by René Descartes. Thomson thought of the universe as a single, connected system, while Descartes believed in three types of matter. Around 60 scientific papers were written by about 25 scientists. Thomson and Tait helped develop knot theory, a part of math called topology. This work continues to inspire new discoveries in science.

Thomson loved sailing, possibly because of his time on the Agamemnon and the Great Eastern. He created a new way to measure the depth of the ocean using a steel piano wire instead of regular rope. This made it easier to take measurements while a ship was moving quickly. He also added a pressure gauge to show how deep the wire went. Around the same time, he improved a method for finding a ship’s location and made tables to help with it.

In the 1880s, Thomson worked to improve compasses used on ships. These tools corrected errors caused by the ship’s metal parts. His design was more stable and had less friction. He used movable iron pieces to fix the compass’s direction. His work built on ideas from other scientists but did not introduce new scientific theories. His efforts helped the British Navy accept his invention.

Charles Babbage first suggested using light patterns to send messages from lighthouses. Thomson supported using Morse code, which uses short and long flashes of light to send messages.

Thomson introduced many accurate tools for measuring electricity. In 1845, he noted that William Snow Harris’s experiments matched Coulomb’s laws. In 1857, he described an electrometer based on an earlier device. He created a series of tools, including the quadrant electrometer, for measuring static electricity. He invented the current balance, also called the Kelvin balance, to define the ampere, the standard unit of electric current. From 1880, he worked with engineer Magnus Maclean on electrical experiments.

In 1893, Thomson led a group to decide the design of the Niagara Falls power station. Even though he believed direct current was better, he supported Westinghouse’s alternating current system, which had been shown at a fair in Chicago. After Niagara Falls, he still thought direct current was superior.

In 1906, Thomson was chosen as the first president of the International Electrotechnical Commission. The group met in London, and he was elected unanimously.

Thomson estimated Earth’s age using physics. He studied how Earth cools and used this to guess its age. He believed the universe’s laws, like thermodynamics, started at the beginning of time. He thought Earth was once too hot for life and disagreed with the idea that Earth’s conditions have always been the same. He said Earth was once a red-hot ball.

After Darwin’s book on evolution was published in 1859, Thomson thought Earth’s short habitable age conflicted with Darwin’s slow process of natural selection. He believed life came from plants brought by meteorites from other planets. His calculations showed the Sun could not have been old enough for evolution unless it had an unknown energy source. He argued with scientists like John Tyndall and Thomas Huxley. In 1869, he presented a speech called “Of Geological Dynamics” to challenge the idea that Earth was billions of years old.

Thomson’s first estimate of Earth’s age was between 20 and 400 million years. His wide range was because he was unsure about the melting point of rocks.

Later life and death

In the winter of 1860–61, Kelvin (37 years old) slipped on ice while playing curling near his home at Netherhall and broke his leg. This injury caused him to miss the 1861 Manchester meeting of the British Association for the Advancement of Science and to limp for the rest of his life. He remained well-known in both the United States and the United Kingdom until his death.

Kelvin always believed in Christianity and attended chapel every day. He thought his faith helped guide his scientific work. This belief is shown in his speech to the Christian Evidence Society on May 23, 1889.

In 1902, Kelvin was named a Privy Councillor and one of the first members of the Order of Merit (OM). He received the honor from King Edward VII on August 8, 1902, and was sworn into the council at Buckingham Palace on August 11, 1902. In his later years, he often visited his townhouse at 15 Eaton Place in Belgravia, London.

In November 1907, Kelvin caught a cold, and his health worsened. He died at his Scottish home, Netherhall, in Largs on December 17. At the request of Westminster Abbey, the coffin was made of oak and lined with lead. The funeral procession left Netherhall for Largs railway station, about a mile away. Many people watched the procession, and shopkeepers closed their businesses and turned off their lights. The coffin was placed in a special train car and sent to London via Kilmarnock on an overnight train.

Kelvin’s funeral took place on December 23, 1907. Westminster Abbey was filled with people, including representatives from the University of Glasgow, the University of Cambridge, and many other countries such as France, Italy, Germany, Austria-Hungary, Russia, the United States, Canada, Australia, Japan, and Monaco. His grave is near the choir in the Abbey, close to the graves of Isaac Newton, John Herschel, and Charles Darwin. Darwin’s son, Sir George Darwin, helped carry the coffin.

The University of Glasgow held a memorial service for Kelvin in the Bute Hall. Kelvin was a member of the Scottish Episcopal Church, attending St Columba’s Episcopal Church in Largs and St Mary’s Episcopal Church in Glasgow (now St Mary’s Cathedral). A service was also held at St Columba’s Church in Largs, attended by many people, including local officials.

Lord Kelvin is remembered on the Thomson family grave in Glasgow Necropolis. The family grave has a second modern memorial, placed by the Royal Philosophical Society of Glasgow, an organization Kelvin led from 1856–58 and 1874–77.

Legacy

In 1884, Kelvin gave a lecture titled "Molecular Dynamics and the Wave Theory of Light" at Johns Hopkins University. He explained the acoustic wave equation, which describes sound as pressure waves in air, and tried to explain an electromagnetic wave equation, assuming a substance called the luminiferous aether could vibrate. The group studying with Kelvin included Albert A. Michelson and Edward W. Morley, who later conducted the Michelson–Morley experiment, which found no evidence of the luminiferous aether. Kelvin did not write a textbook, but A. S. Hathaway took notes and copied them using a papyrograph. Because the subject was still developing, Kelvin revised the notes, and in 1904, they were printed and published. Kelvin’s efforts to create mechanical models for electromagnetic waves did not succeed. Starting from his 1884 lecture, he was the first scientist to suggest the idea of dark matter, and he tried to identify "dark bodies" in the Milky Way.

Kelvin was unsure about Maxwell’s prediction that radiation pressure exists, but he later accepted it after seeing Pyotr Lebedev’s experiments proving it.

On 27 April 1900, Kelvin gave a lecture at the Royal Institution titled "Nineteenth-Century Clouds over the Dynamical Theory of Heat and Light." He referred to two major problems: confusion about how matter moves through the aether (including the results of the Michelson–Morley experiment) and questions about whether the equipartition theorem in statistical mechanics might not work. These issues led to the development of two major theories in the 20th century: the theory of relativity and quantum mechanics. In 1905, Albert Einstein published papers that explained the photoelectric effect using Max Planck’s idea of energy quanta, described special relativity, and explained Brownian motion through statistical mechanics, supporting the existence of atoms.

Like many scientists, Thomson made incorrect predictions about future technology. His biographer, Silvanus P. Thompson, wrote that Kelvin was skeptical about X-rays when they were first discovered in 1895, but he changed his mind after receiving a copy of the research from Röntgen. In 1896, after seeing X-ray images, Kelvin wrote to Röntgen, expressing his surprise and happiness about the discovery. Kelvin had his own hand X-rayed in May 1896.

Kelvin believed practical aviation, such as heavier-than-air aircraft, would not work. In 1896, he refused to join the Aeronautical Society, stating he had "no faith" in aerial navigation other than ballooning. In 1902, he predicted that "no balloon and no aeroplane will ever be practically successful."

A quote often falsely said to be from Kelvin is: "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement." This quote is not known to have been said by Kelvin. It is instead a paraphrase of Albert A. Michelson, who in 1894 said, "It seems probable that most of the grand underlying principles have been firmly established." Similar statements were made earlier by others. The confusion likely came from Kelvin’s 1900 lecture, which pointed out areas of science that would later change.

In 1898, Kelvin predicted that Earth’s oxygen supply would last only 400 years because of how quickly combustible materials were being burned.

Many scientific terms and concepts are named after Kelvin, including:

• Mount Kelvin in New Zealand’s Paparoa Range, named by botanist William Trownson.
• Fellow of the Royal Society of Edinburgh (1847); Keith Medal (1864); Gunning Victoria Jubilee Prize (1887); President (1873–1878, 1886–1890, 1895–1907).
• Foreign member of the Royal Swedish Academy of Sciences (1851).
• Honorary member of the Manchester Literary and Philosophical Society (1851).
• Fellow of the Royal Society (1851); Royal Medal (1856); Copley Medal (1883); President (1890–1895).
• Honorary member of the Royal College of Preceptors (1858).
• Honorary member of the Institution of Engineers and Shipbuilders in Scotland (1859).
• Knighted (1866).
• Commander of the Imperial Order of the Rose (Brazil) (1873).
• Commander of the Legion of Honour (France) (1881); Grand Officer of the Legion of Honour (1889).
• Knight of the Prussian Order Pour le Mérite (1884).
• Commander of the Order of Leopold (Belgium) (1890).
• Baron Kelvin, of Largs in the County of Ayr (1892). The title was not passed on, as Kelvin had no heirs. A memorial to him stands in Kelvingrove Park near the University of Glasgow.
• Knight Grand Cross of the Victorian Order (1896).
• Honorary degree of Doctor of Laws (LL.D.) from Yale University (1902).
• One of the first members of the Order of Merit (1902).
• Privy Counsellor (1902).
• Honorary degree of Doctor of Mathematics from the Royal Frederick University (1902).
• First international recipient of the John Fritz Medal (1905).
• Order of the First Class of the Sacred Treasure of Japan (1901).
• Buried in Westminster Abbey, London, next to Isaac Newton.
• Featured on the £20 note of the Clydesdale Bank (1971) and the £100 note (current issue). He is shown holding a compass, with a map of the transatlantic cable in the background.
• Inducted into the Scottish Engineering Hall of Fame (2011).
• World Refrigeration Day is 26 June, chosen to honor his birthday and celebrated annually since 2019.

Cited sources

• Lindley, D. (2004). Degrees Kelvin: A Story About Genius, Inventions, and Tragedy. Joseph Henry Press. ISBN 978-0-309-09073-5.
• Sharlin, H. I. (1979). Lord Kelvin: The Dynamic Victorian. Pennsylvania State University Press. ISBN 978-0-271-00203-3.