William Thomson, 1st Baron Kelvin
Encyclopedia
William Thomson, 1st Baron Kelvin OM, GCVO
Royal Victorian Order
The Royal Victorian Order is a dynastic order of knighthood and a house order of chivalry recognising distinguished personal service to the order's Sovereign, the reigning monarch of the Commonwealth realms, any members of her family, or any of her viceroys...

, PC, PRS, PRSE, (26 June 1824 – 17 December 1907) was a mathematical physicist
Mathematical physics
Mathematical physics refers to development of mathematical methods for application to problems in physics. The Journal of Mathematical Physics defines this area as: "the application of mathematics to problems in physics and the development of mathematical methods suitable for such applications and...

 and engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...

. At the University of Glasgow
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...

 he did important work in the mathematical analysis
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

 of electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

 and formulation of the first and second laws of thermodynamics
Laws of thermodynamics
The four laws of thermodynamics summarize its most important facts. They define fundamental physical quantities, such as temperature, energy, and entropy, in order to describe thermodynamic systems. They also describe the transfer of energy as heat and work in thermodynamic processes...

, and did much to unify the emerging discipline of physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 in its modern form. He worked closely with mathematics professor Hugh Blackburn
Hugh Blackburn
Bailie Hugh Blackburn was a Scottish mathematician. A lifelong friend of William Thomson , and the husband of illustrator Jemima Blackburn, he was professor of mathematics at the University of Glasgow from 1849 to 1879...

 in his work. He also had a career as an electric telegraph engineer and inventor, which propelled him into the public eye and ensured his wealth, fame and honor. For his work on the transatlantic telegraph project he was knighted
Knight Bachelor
The rank of Knight Bachelor is a part of the British honours system. It is the most basic rank of a man who has been knighted by the monarch but not as a member of one of the organised Orders of Chivalry...

 by Queen Victoria
Victoria of the United Kingdom
Victoria was the monarch of the United Kingdom of Great Britain and Ireland from 20 June 1837 until her death. From 1 May 1876, she used the additional title of Empress of India....

, becoming Sir William Thomson. He had extensive maritime interests and was most noted for his work on the mariner's compass, which had previously been limited in reliability.

Lord Kelvin is widely known for realising that there was a lower limit to temperature, absolute zero
Absolute zero
Absolute zero is the theoretical temperature at which entropy reaches its minimum value. The laws of thermodynamics state that absolute zero cannot be reached using only thermodynamic means....

; absolute temperatures are stated in units of kelvin
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

 in his honour. On his ennoblement in honour of his achievements in thermodynamics, and of his opposition to Irish Home Rule
Home rule
Home rule is the power of a constituent part of a state to exercise such of the state's powers of governance within its own administrative area that have been devolved to it by the central government....

, he adopted the title Baron
Baron
Baron is a title of nobility. The word baron comes from Old French baron, itself from Old High German and Latin baro meaning " man, warrior"; it merged with cognate Old English beorn meaning "nobleman"...

 Kelvin of Largs
Largs
Largs is a town on the Firth of Clyde in North Ayrshire, Scotland, about from Glasgow. The original name means "the slopes" in Scottish Gaelic....

and is therefore often described as Lord
Lord
Lord is a title with various meanings. It can denote a prince or a feudal superior . The title today is mostly used in connection with the peerage of the United Kingdom or its predecessor countries, although some users of the title do not themselves hold peerages, and use it 'by courtesy'...

 Kelvin. He was the first UK scientist to be elevated to the House of Lords
House of Lords
The House of Lords is the upper house of the Parliament of the United Kingdom. Like the House of Commons, it meets in the Palace of Westminster....

. The title refers to the River Kelvin
River Kelvin
The Kelvin rises on watershed of Scotland on the moor south east of the village of Banton, east of Kilsyth - . At almost 22 miles long, it initially flows south to Dullatur Bog where it falls into a man made trench and takes a ninety degree turn flowing west along the northern boundary of the bog...

, which flows close by his laboratory at the University of Glasgow
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...

. His home was the imposing red sandstone mansion Netherhall, in Largs on the Firth of Clyde
Firth of Clyde
The Firth of Clyde forms a large area of coastal water, sheltered from the Atlantic Ocean by the Kintyre peninsula which encloses the outer firth in Argyll and Ayrshire, Scotland. The Kilbrannan Sound is a large arm of the Firth of Clyde, separating the Kintyre Peninsula from the Isle of Arran.At...

. Despite offers of elevated posts from several world renowned universities Lord Kelvin refused to leave Glasgow, remaining Professor of Natural Philosophy for over 50 years, until his eventual retirement from that post. The Hunterian Museum at the University of Glasgow
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...

 has a permanent exhibition on the work of Lord Kelvin including many of his original papers, instruments and other artifacts.

Family

William Thomson's father, James Thomson
James Thomson (mathematician)
James Thomson was an Irish mathematician, notable for his role in the formation of the thermodynamics school at Glasgow University...

, was a teacher of mathematics and engineering at Royal Belfast Academical Institution
Royal Belfast Academical Institution
The Royal Belfast Academical Institution, is a Grammar School in Belfast, Northern Ireland. Locally referred to as Inst, the school educates boys from ages 11–18...

 and the son of a farmer. James Thomson married Margaret Gardner in 1817 and, of their children, four boys and two girls survived infancy. Margaret Thomson died in 1830 when William was six years old.

William and his elder brother James
James Thomson (engineer)
right|300px|James Thomson was an engineer and physicist whose reputation is substantial though it is overshadowed by that of his younger brother William Thomson .-Biography:Born in Belfast, he grew up mostly in Glasgow...

 were tutored at home by their father while the younger boys were tutored by their elder sisters. James was intended to benefit from the major share of his father's encouragement, affection and financial support and was prepared for a career in engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

.

In 1832, his father was appointed professor of mathematics at Glasgow and the family moved there in October 1833. The Thomson children were introduced to a broader cosmopolitan experience than their father's rural upbringing, spending mid-1839 in London and, the boys, being tutored in French in Paris. Mid-1840 was spent in Germany and the Netherlands. Language study was given a high priority.

Youth

Thomson had heart problems and nearly died when he was 9 years old. He attended the Royal Belfast Academical Institution
Royal Belfast Academical Institution
The Royal Belfast Academical Institution, is a Grammar School in Belfast, Northern Ireland. Locally referred to as Inst, the school educates boys from ages 11–18...

, where his father was a professor in the university department, before beginning study at Glasgow University in 1834 at the age of 10, not out of any precociousness; the University provided many of the facilities of an elementary school for able pupils, and this was a typical starting age.

In school, Thomson showed a keen interest in the classics along with his natural interest in the sciences. At the age of 12 he won a prize for translating Lucian of Samosata's Dialogues of the Gods from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 to English.

In the academic year 1839/1840, Thomson won the class prize in astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 for his Essay on the figure of the Earth which showed an early facility for mathematical analysis and creativity. Throughout his life, he would work on the problems raised in the essay as a coping
Coping (psychology)
Coping has been defined in psychological terms by Susan Folkman and Richard Lazarus as "constantly changing cognitive and behavioral efforts to manage specific external and/or internal demands that are appraised as taxing" or "exceeding the resources of the person".Coping is thus expending...

 strategy at times of personal stress
Stress (medicine)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...

. On the title page of this essay Thomson wrote the following lines from Alexander Pope's
Alexander Pope
Alexander Pope was an 18th-century English poet, best known for his satirical verse and for his translation of Homer. He is the third-most frequently quoted writer in The Oxford Dictionary of Quotations, after Shakespeare and Tennyson...

 Essay on Man. These lines inspired Thomson to understand the natural world using the power and method of science:
Thomson became intrigued with Fourier's
Joseph Fourier
Jean Baptiste Joseph Fourier was a French mathematician and physicist best known for initiating the investigation of Fourier series and their applications to problems of heat transfer and vibrations. The Fourier transform and Fourier's Law are also named in his honour...

 Théorie analytique de la chaleur and committed himself to study the "Continental" mathematics resisted by a British establishment still working in the shadow of Sir Isaac Newton
Isaac Newton
Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...

. Unsurprisingly, Fourier's work had been attacked by domestic mathematicians, Philip Kelland
Philip Kelland
Philip Kelland PRSE FRS was an English mathematician. He was known mainly for his great influence on the development of education in Scotland.-Early life:Kelland was born in 1808 in Dunster, Somerset, England...

 authoring a critical book. The book motivated Thomson to write his first published scientific paper under the pseudonym
Pseudonym
A pseudonym is a name that a person assumes for a particular purpose and that differs from his or her original orthonym...

 P.Q.R., defending Fourier, and submitted to the Cambridge Mathematical Journal by his father. A second P.Q.R paper followed almost immediately.

While holidaying with his family in Lamlash
Lamlash
Lamlash is the largest village by population on the Isle of Arran, in the Firth of Clyde, Scotland. It lies 4 miles to the south of ferry port Brodick, in a sheltered bay on the island's east coast, facing Holy Isle. Lamlash is the seat of Arran's local government offices and police...

 in 1841, he wrote a third, more substantial, P.Q.R. paper On the uniform motion of heat in homogeneous solid bodies, and its connection with the mathematical theory of electricity. In the paper he made remarkable connections between the mathematical theories of heat conduction
Heat conduction
In heat transfer, conduction is a mode of transfer of energy within and between bodies of matter, due to a temperature gradient. Conduction means collisional and diffusive transfer of kinetic energy of particles of ponderable matter . Conduction takes place in all forms of ponderable matter, viz....

 and electrostatics
Electrostatics
Electrostatics is the branch of physics that deals with the phenomena and properties of stationary or slow-moving electric charges....

, an analogy
Analogy
Analogy is a cognitive process of transferring information or meaning from a particular subject to another particular subject , and a linguistic expression corresponding to such a process...

 that James Clerk Maxwell
James Clerk Maxwell
James Clerk Maxwell of Glenlair was a Scottish physicist and mathematician. His most prominent achievement was formulating classical electromagnetic theory. This united all previously unrelated observations, experiments and equations of electricity, magnetism and optics into a consistent theory...

 was ultimately to describe as one of the most valuable science-forming ideas.

Cambridge

William's father was able to make a generous provision for his favourite son's education and, in 1841, installed him, with extensive letters of introduction and ample accommodation, at Peterhouse, Cambridge
Peterhouse, Cambridge
Peterhouse is a constituent college of the University of Cambridge, England. It is the oldest college of the University, having been founded in 1284 by Hugo de Balsham, Bishop of Ely...

. In 1845 Thomson graduated as Second Wrangler. He also won a Smith's Prize
Smith's Prize
The Smith's Prize was the name of each of two prizes awarded annually to two research students in theoretical Physics, mathematics and applied mathematics at the University of Cambridge, Cambridge, England.- History :...

,
which, unlike the tripos
Tripos
The University of Cambridge, England, divides the different kinds of honours bachelor's degree by Tripos , plural Triposes. The word has an obscure etymology, but may be traced to the three-legged stool candidates once used to sit on when taking oral examinations...

, is a test of original research. Robert Leslie Ellis
Robert Leslie Ellis
Robert Leslie Ellis was an English polymath, remembered principally as a mathematician and editor of the works of Francis Bacon....

, one of the examiners, is said to have declared to another examiner You and I are just about fit to mend his pens.

While at Cambridge, Thomson was active in sports, athletics and sculling
Sculling
Sculling generally refers to a method of using oars to propel watercraft in which the oar or oars touch the water on both the port and starboard sides of the craft, or over the stern...

, winning the Colquhoun Sculls in 1843. He also took a lively interest in the classics, music, and literature; but the real love of his intellectual life was the pursuit of science. The study of mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

, physics, and in particular, of electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

, had captivated his imagination.

In 1845 he gave the first mathematical development of Faraday
Michael Faraday
Michael Faraday, FRS was an English chemist and physicist who contributed to the fields of electromagnetism and electrochemistry....

's idea that electric induction takes place through an intervening medium, or "dielectric", and not by some incomprehensible "action at a distance". He also devised a hypothesis of electrical images, which became a powerful agent in solving problems of electrostatics, or the science which deals with the forces of electricity at rest. It was partly in response to his encouragement that Faraday undertook the research in September 1845 that led to the discovery of the Faraday effect
Faraday effect
In physics, the Faraday effect or Faraday rotation is a Magneto-optical phenomenon, that is, an interaction between light and a magnetic field in a medium...

, which established that light and magnetic (and thus electric) phenomena were related.

He was elected a fellow of St. Peter's
Peterhouse, Cambridge
Peterhouse is a constituent college of the University of Cambridge, England. It is the oldest college of the University, having been founded in 1284 by Hugo de Balsham, Bishop of Ely...

 (as Peterhouse was often called at the time) in June 1845. On gaining the fellowship, he spent some time in the laboratory of the celebrated Henri Victor Regnault
Henri Victor Regnault
Henri Victor Regnault was a French chemist and physicist best known for his careful measurements of the thermal properties of gases. He was an early thermodynamicist and was mentor to William Thomson in the late 1840s....

, at Paris; but in 1846 he was appointed to the chair of natural philosophy
Professor of Natural Philosophy, Glasgow
The Chair of Natural Philosophy is a professorship at the University of Glasgow which was established in 1727The Nova Erectio of King James VI of Scotland shared the teaching of Moral Philosophy, Logic and Natural Philosophy among the Regents....

 in the University of Glasgow
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...

. At twenty-two he found himself wearing the gown of a learned professor in one of the oldest Universities in the country, and lecturing to the class of which he was a freshman but a few years before.

Thermodynamics

By 1847, Thomson had already gained a reputation as a precocious and maverick scientist when he attended the British Association for the Advancement of Science
British Association for the Advancement of Science
frame|right|"The BA" logoThe British Association for the Advancement of Science or the British Science Association, formerly known as the BA, is a learned society with the object of promoting science, directing general attention to scientific matters, and facilitating interaction between...

 annual meeting in Oxford
Oxford
The city of Oxford is the county town of Oxfordshire, England. The city, made prominent by its medieval university, has a population of just under 165,000, with 153,900 living within the district boundary. It lies about 50 miles north-west of London. The rivers Cherwell and Thames run through...

. At that meeting, he heard James Prescott Joule
James Prescott Joule
James Prescott Joule FRS was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work . This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics. The...

 making yet another of his, so far, ineffective attempts to discredit the caloric theory
Caloric theory
The caloric theory is an obsolete scientific theory that heat consists of a self-repellent fluid called caloric that flows from hotter bodies to colder bodies. Caloric was also thought of as a weightless gas that could pass in and out of pores in solids and liquids...

 of heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

 and the theory of the heat engine
Heat engine
In thermodynamics, a heat engine is a system that performs the conversion of heat or thermal energy to mechanical work. It does this by bringing a working substance from a high temperature state to a lower temperature state. A heat "source" generates thermal energy that brings the working substance...

 built upon it by Sadi Carnot
Nicolas Léonard Sadi Carnot
Nicolas Léonard Sadi Carnot was a French military engineer who, in his 1824 Reflections on the Motive Power of Fire, gave the first successful theoretical account of heat engines, now known as the Carnot cycle, thereby laying the foundations of the second law of thermodynamics...

 and Émile Clapeyron. Joule argued for the mutual convertibility of heat and mechanical work
Mechanical work
In physics, work is a scalar quantity that can be described as the product of a force times the distance through which it acts, and it is called the work of the force. Only the component of a force in the direction of the movement of its point of application does work...

 and for their mechanical equivalence.

Thomson was intrigued but skeptical. Though he felt that Joule's results demanded theoretical explanation, he retreated into an even deeper commitment to the Carnot–Clapeyron school. He predicted that the melting point
Melting point
The melting point of a solid is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard atmospheric pressure...

 of ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...

 must fall with pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

, otherwise its expansion on freezing could be exploited in a perpetuum mobile
Perpetual motion
Perpetual motion describes hypothetical machines that operate or produce useful work indefinitely and, more generally, hypothetical machines that produce more work or energy than they consume, whether they might operate indefinitely or not....

. Experimental confirmation in his laboratory did much to bolster his beliefs.

In 1848, he extended the Carnot–Clapeyron theory still further through his dissatisfaction that the gas thermometer
Gas thermometer
A gas thermometer measures temperature by the variation in volume or pressure of a gas. One common apparatus is a constant volume thermometer. It consists of a bulb connected by a capillary tube to a manometer. The bulb is filled with a gas such that the volume of the gas in the bulb remains...

 provided only an operational definition
Operational definition
An operational definition defines something in terms of the specific process or set of validation tests used to determine its presence and quantity. That is, one defines something in terms of the operations that count as measuring it. The term was coined by Percy Williams Bridgman and is a part of...

 of temperature. He proposed an absolute temperature scale in which a unit of heat descending from a body A at the temperature T° of this scale, to a body B at the temperature (T−1)°, would give out the same mechanical effect [work], whatever be the number T. Such a scale would be quite independent of the physical properties of any specific substance. By employing such a "waterfall", Thomson postulated that a point would be reached at which no further heat (caloric) could be transferred, the point of absolute zero
Absolute zero
Absolute zero is the theoretical temperature at which entropy reaches its minimum value. The laws of thermodynamics state that absolute zero cannot be reached using only thermodynamic means....

about which Guillaume Amontons
Guillaume Amontons
Guillaume Amontons was a French scientific instrument inventor and physicist. He was one of the pioneers in tribology, apart from Leonardo da Vinci, John Theophilus Desaguliers, Leonard Euler and Charles-Augustin de Coulomb.-Life:Guillaume was born in Paris, France. His father was a lawyer from...

 had speculated in 1702. Thomson used data published by Regnault to calibrate
Calibration
Calibration is a comparison between measurements – one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device....

 his scale against established measurements.

In his publication, Thomson wrote:
— But a footnote signalled his first doubts about the caloric theory, referring to Joule's very remarkable discoveries. Surprisingly, Thomson did not send Joule a copy of his paper, but when Joule eventually read it he wrote to Thomson on 6 October, claiming that his studies had demonstrated conversion of heat into work but that he was planning further experiments. Thomson replied on 27 October, revealing that he was planning his own experiments and hoping for a reconciliation of their two views.

Thomson returned to critique Carnot's original publication and read his analysis to the Royal Society of Edinburgh
Royal Society of Edinburgh
The Royal Society of Edinburgh is Scotland's national academy of science and letters. It is a registered charity, operating on a wholly independent and non-party-political basis and providing public benefit throughout Scotland...

 in January 1849, still convinced that the theory was fundamentally sound. However, though Thomson conducted no new experiments, over the next two years he became increasingly dissatisfied with Carnot's theory and convinced of Joule's. In February 1851 he sat down to articulate his new thinking. However, he was uncertain of how to frame his theory and the paper went through several drafts before he settled on an attempt to reconcile Carnot and Joule. During his rewriting, he seems to have considered ideas that would subsequently give rise to the second law of thermodynamics
Second law of thermodynamics
The second law of thermodynamics is an expression of the tendency that over time, differences in temperature, pressure, and chemical potential equilibrate in an isolated physical system. From the state of thermodynamic equilibrium, the law deduced the principle of the increase of entropy and...

. In Carnot's theory, lost heat was absolutely lost but Thomson contended that it was "lost to man irrecoverably; but not lost in the material world". Moreover, his theological
Theology
Theology is the systematic and rational study of religion and its influences and of the nature of religious truths, or the learned profession acquired by completing specialized training in religious studies, usually at a university or school of divinity or seminary.-Definition:Augustine of Hippo...

 beliefs led to speculation about the heat death of the universe
Heat death of the universe
The heat death of the universe is a suggested ultimate fate of the universe, in which the universe has diminished to a state of no thermodynamic free energy and therefore can no longer sustain motion or life. Heat death does not imply any particular absolute temperature; it only requires that...

.
Compensation would require a creative act or an act possessing similar power.

In final publication, Thomson retreated from a radical departure and declared "the whole theory of the motive power of heat is founded on ... two ... propositions, due respectively to Joule, and to Carnot and Clausius." Thomson went on to state a form of the second law:
In the paper, Thomson supported the theory that heat was a form of motion but admitted that he had been influenced only by the thought of Sir Humphry Davy
Humphry Davy
Sir Humphry Davy, 1st Baronet FRS MRIA was a British chemist and inventor. He is probably best remembered today for his discoveries of several alkali and alkaline earth metals, as well as contributions to the discoveries of the elemental nature of chlorine and iodine...

 and the experiments of Joule and Julius Robert von Mayer
Julius Robert von Mayer
Julius Robert von Mayer was a German physician and physicist and one of the founders of thermodynamics...

, maintaining that experimental demonstration of the conversion of heat into work was still outstanding.

As soon as Joule read the paper he wrote to Thomson with his comments and questions. Thus began a fruitful, though largely epistolary, collaboration between the two men, Joule conducting experiments, Thomson analysing the results and suggesting further experiments. The collaboration lasted from 1852 to 1856, its discoveries including the Joule–Thomson effect
Joule–Thomson effect
In thermodynamics, the Joule–Thomson effect or Joule–Kelvin effect or Kelvin–Joule effect describes the temperature change of a gas or liquid when it is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the environment. This procedure is called a...

, sometimes called the Kelvin–Joule effect, and the published results did much to bring about general acceptance of Joule's work and the kinetic theory
Kinetic theory
The kinetic theory of gases describes a gas as a large number of small particles , all of which are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of the container...

.

Thomson published more than 600 scientific papers and applied for 70 patents (not all were issued).

Calculations on data rate

Though now eminent in the academic field, Thomson was obscure to the general public. In September 1852, he married childhood sweetheart Margaret Crum, daughter of Alexander Crum
Alexander Crum
Alexander Crum was a Scottish printer and Liberal Party politician who sat in the House of Commons from 1880 to 1885.Crum was the eldest son of Walter Crum FRS of Thornliebank and his wife Jesse Graham, daughter of William Graham of Burntshiel, Renfrewshire. The Crum family were associated with...

 but her health broke down on their honeymoon and, over the next seventeen years, Thomson was distracted by her suffering. On 16 October 1854, George Gabriel Stokes
George Gabriel Stokes
Sir George Gabriel Stokes, 1st Baronet FRS , was an Irish mathematician and physicist, who at Cambridge made important contributions to fluid dynamics , optics, and mathematical physics...

 wrote to Thomson to try to re-interest him in work by asking his opinion on some experiments of Michael Faraday
Michael Faraday
Michael Faraday, FRS was an English chemist and physicist who contributed to the fields of electromagnetism and electrochemistry....

 on the proposed transatlantic telegraph cable
Transatlantic telegraph cable
The transatlantic telegraph cable was the first cable used for telegraph communications laid across the floor of the Atlantic Ocean. It crossed from , Foilhommerum Bay, Valentia Island, in western Ireland to Heart's Content in eastern Newfoundland. The transatlantic cable connected North America...

.

Faraday had demonstrated how the construction of a cable would limit the rate at which messages could be sent — in modern terms, the bandwidth
Bandwidth (computing)
In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it .Note that in textbooks on wireless communications, modem data transmission,...

. Thomson jumped at the problem and published his response that month. He expressed his results in terms of the data rate
Data signaling rate
In telecommunication, data signaling rate , also known as gross bit rate, is the aggregate rate at which data pass a point in the transmission path of a data transmission system.Notes:#The DSR is usually expressed in bits per second....

 that could be achieved and the economic
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

 consequences in terms of the potential revenue
Revenue
In business, revenue is income that a company receives from its normal business activities, usually from the sale of goods and services to customers. In many countries, such as the United Kingdom, revenue is referred to as turnover....

 of the transatlantic undertaking. In a further 1855 analysis, Thomson stressed the impact that the design of the cable would have on its profit
Profit (accounting)
In accounting, profit can be considered to be the difference between the purchase price and the costs of bringing to market whatever it is that is accounted as an enterprise in terms of the component costs of delivered goods and/or services and any operating or other expenses.-Definition:There are...

ability.

Thomson contended that the speed of a signal through a given core was inversely proportional to the square of the length of the core. Thomson's results were disputed at a meeting of the British Association in 1856 by Wildman Whitehouse
Wildman Whitehouse
Edward Orange Wildman Whitehouse was an English surgeon, better-known for his ultimately unsuccessful endeavours as chief electrician of the transatlantic telegraph cable for the Atlantic Telegraph Company.-Life:...

, the electrician
Electrician
An electrician is a tradesman specializing in electrical wiring of buildings, stationary machines and related equipment. Electricians may be employed in the installation of new electrical components or the maintenance and repair of existing electrical infrastructure. Electricians may also...

 of the Atlantic Telegraph Company
Atlantic Telegraph Company
The Atlantic Telegraph Company was a company formed in 1856 to undertake and exploit a commercial telegraph cable across the Atlantic ocean, the first such telecommunications link....

. Whitehouse had possibly misinterpreted the results of his own experiments but was doubtless feeling financial pressure as plans for the cable were already well underway. He believed that Thomson's calculations implied that the cable must be "abandoned as being practically and commercially impossible."

Thomson attacked Whitehouse's contention in a letter to the popular Athenaeum
Athenaeum (magazine)
The Athenaeum was a literary magazine published in London from 1828 to 1921. It had a reputation for publishing the very best writers of the age....

magazine, pitching himself into the public eye. Thomson recommended a larger conductor with a larger cross section
Cross section (geometry)
In geometry, a cross-section is the intersection of a figure in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc...

 of insulation
Electrical insulation
thumb|250px|[[Coaxial Cable]] with dielectric insulator supporting a central coreThis article refers to electrical insulation. For insulation of heat, see Thermal insulation...

. However, he thought Whitehouse no fool and suspected that he might have the practical skill to make the existing design work. Thomson's work had, however, caught the eye of the project's undertakers and in December 1856, he was elected to the board of directors
Board of directors
A board of directors is a body of elected or appointed members who jointly oversee the activities of a company or organization. Other names include board of governors, board of managers, board of regents, board of trustees, and board of visitors...

 of the Atlantic Telegraph Company.

Scientist to engineer

Thomson became scientific adviser to a team with Whitehouse as chief electrician and Sir Charles Tilston Bright
Charles Tilston Bright
Sir Charles Tilston Bright was a British electrical engineer who oversaw the laying of the first transatlantic telegraph cable in 1858, for which work he was knighted....

 as chief engineer but Whitehouse had his way with the specification, supported by Faraday and Samuel F. B. Morse
Samuel F. B. Morse
Samuel Finley Breese Morse was an American contributor to the invention of a single-wire telegraph system based on European telegraphs, co-inventor of the Morse code, and an accomplished painter.-Birth and education:...

.

Thomson sailed on board the cable-laying ship HMS Agamemnon
HMS Agamemnon (1852)
HMS Agamemnon was a Royal Navy 91-gun battleship ordered by the Admiralty in 1849 in response to the perceived threat from France by their possession of ships of the Napoléon class...

 in August 1857, with Whitehouse confined to land owing to illness, but the voyage ended after 380 miles (611.5 km) when the cable parted. Thomson contributed to the effort by publishing in the Engineer the whole theory of the stress
Stress (physics)
In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are a reaction to external forces applied on the body...

es involved in the laying of a submarine cable
Cable
A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...

, and showed that when the line is running out of the ship, at a constant speed, in a uniform depth of water, it sinks in a slant or straight incline from the point where it enters the water to that where it touches the bottom.

Thomson developed a complete system for operating a submarine telegraph that was capable of sending a character
Character (computing)
In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language....

 every 3.5 seconds. He patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

ed the key elements of his system, the mirror galvanometer
Mirror galvanometer
thumb|right|200px|A mirror galvanometerA mirror galvanometer is a mechanical meter that senses electric current, except that instead of moving a needle, it moves a mirror. The mirror reflects a beam of light, which projects onto a meter, and acts as a long, weightless, massless pointer...

 and the siphon recorder
Siphon recorder
The syphon or siphon recorder is an item of telecommunications equipment invented by William Thomson, 1st Baron Kelvin in 1858. It was used to automatically record the receipt of a telegraph message, as a wiggling ink line on a roll of paper tape...

, in 1858.

Whitehouse still felt able to ignore Thomson's many suggestions and proposals. It was not until Thomson convinced the board that using purer copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 for replacing the lost section of cable would improve data capacity, that he first made a difference to the execution of the project.

The board insisted that Thomson join the 1858 cable-laying expedition, without any financial compensation, and take an active part in the project. In return, Thomson secured a trial for his mirror galvanometer, about which the board had been unenthusiastic, alongside Whitehouse's equipment. However, Thomson found the access he was given unsatisfactory and the Agamemnon had to return home following the disastrous storm of June 1858. Back in London, the board was on the point of abandoning the project and mitigating their losses by selling the cable. Thomson, Cyrus West Field
Cyrus West Field
Cyrus West Field was an American businessman and financier who, along with other entrepreneurs, created the Atlantic Telegraph Company and laid the first telegraph cable across the Atlantic Ocean in 1858.-Life and career:...

 and Curtis M. Lampson argued for another attempt and prevailed, Thomson insisting that the technical problems were tractable. Though employed in an advisory capacity, Thomson had, during the voyages, developed real engineer's instincts and skill at practical problem-solving under pressure, often taking the lead in dealing with emergencies and being unafraid to lend a hand in manual work. A cable was finally completed on 5 August.

Disaster and triumph

Thomson's fears were realised and Whitehouse's apparatus proved insufficiently sensitive and had to be replaced by Thomson's mirror galvanometer. Whitehouse continued to maintain that it was his equipment that was providing the service and started to engage in desperate measures to remedy some of the problems. He succeeded only in fatally damaging the cable by applying 2,000 V
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...

. When the cable failed completely Whitehouse was dismissed, though Thomson objected and was reprimanded by the board for his interference. Thomson subsequently regretted that he had acquiesced too readily to many of Whitehouse's proposals and had not challenged him with sufficient energy.

A joint committee of inquiry was established by the Board of Trade
Board of Trade
The Board of Trade is a committee of the Privy Council of the United Kingdom, originating as a committee of inquiry in the 17th century and evolving gradually into a government department with a diverse range of functions...

 and the Atlantic Telegraph Company. Most of the blame for the cable's failure was found to rest with Whitehouse. The committee found that, though underwater cables were notorious in their lack of reliability
Reliability engineering
Reliability engineering is an engineering field, that deals with the study, evaluation, and life-cycle management of reliability: the ability of a system or component to perform its required functions under stated conditions for a specified period of time. It is often measured as a probability of...

, most of the problems arose from known and avoidable causes. Thomson was appointed one of a five-member committee to recommend a specification for a new cable. The committee reported in October 1863.

In July 1865 Thomson sailed on the cable-laying expedition of the but the voyage was again dogged with technical problems. The cable was lost after 1200 miles (1,931.2 km) had been laid and the expedition had to be abandoned. A further expedition in 1866 managed to lay a new cable in two weeks and then go on to recover and complete the 1865 cable. The enterprise was now feted as a triumph by the public and Thomson enjoyed a large share of the adulation. Thomson, along with the other principals of the project, was knighted on 10 November 1866.

To exploit his inventions for signalling on long submarine cables, Thomson now entered into a partnership with C.F. Varley and Fleeming Jenkin
Fleeming Jenkin
Henry Charles Fleeming Jenkin was Professor of Engineering at the University of Edinburgh, remarkable for his versatility. Known to the world as the inventor of telpherage, he was an electrician and cable engineer, economist, lecturer, linguist, critic, actor, dramatist and artist...

. In conjunction with the latter, he also devised an automatic curb sender
Automatic curb sender
The automatic curb sender was a kind of telegraph key, invented by William Thomson, 1st Baron Kelvin for sending messages on a submarine cable, as the well-known Wheatstone transmitter sends them on a land line....

, a kind of telegraph key
Telegraph key
Telegraph key is a general term for any switching device used primarily to send Morse code. Similar keys are used for all forms of manual telegraphy, such as in electrical telegraph and radio telegraphy.- Types of keys :...

 for sending messages on a cable.

Later expeditions

Thomson took part in the laying of the French Atlantic submarine communications cable
Submarine communications cable
A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean....

 of 1869, and with Jenkin was engineer of the Western and Brazilian and Platino-Brazilian cables, assisted by vacation student James Alfred Ewing
James Alfred Ewing
Sir James Alfred Ewing KCB FRS FRSE MInstitCE was a Scottish physicist and engineer, best known for his work on the magnetic properties of metals and, in particular, for his discovery of, and coinage of the word, hysteresis.It was said of Ewing that he was 'Careful at all times of his appearance,...

. He was present at the laying of the Pará
Belém
Belém is a Brazilian city, the capital and largest city of state of Pará, in the country's north region. It is the entrance gate to the Amazon with a busy port, airport and bus/coach station...

 to Pernambuco
Pernambuco
Pernambuco is a state of Brazil, located in the Northeast region of the country. To the north are the states of Paraíba and Ceará, to the west is Piauí, to the south are Alagoas and Bahia, and to the east is the Atlantic Ocean. There are about of beaches, some of the most beautiful in the...

 section of the Brazilian coast cables in 1873.

Thomson's wife had died on 17 June 1870 and he resolved to make changes in his life. Already addicted to seafaring, in September he purchased a 126 ton schooner
Schooner
A schooner is a type of sailing vessel characterized by the use of fore-and-aft sails on two or more masts with the forward mast being no taller than the rear masts....

, the Lalla Rookh and used it as a base for entertaining friends and scientific colleagues. His maritime interests continued in 1871 when he was appointed to the board of enquiry into the sinking of the .

In June 1873, Thomson and Jenkin were on board the Hooper, bound for Lisbon
Lisbon
Lisbon is the capital city and largest city of Portugal with a population of 545,245 within its administrative limits on a land area of . The urban area of Lisbon extends beyond the administrative city limits with a population of 3 million on an area of , making it the 9th most populous urban...

 with 2500 miles (4,023.4 km) of cable when the cable developed a fault. An unscheduled 16-day stop-over in Madeira
Madeira
Madeira is a Portuguese archipelago that lies between and , just under 400 km north of Tenerife, Canary Islands, in the north Atlantic Ocean and an outermost region of the European Union...

 followed and Thomson became good friends with Charles R. Blandy and his three daughters. On 2 May 1874 he set sail for Madeira on the Lalla Rookh. As he approached the harbour, he signalled to the Blandy residence "Will you marry me?" and Fanny signalled back "Yes". Thomson married Fanny, 13 years his junior, on 24 June 1874.

Thomson and Tait: Treatise on Natural Philosophy

Over the period 1855 to 1867, Thomson collaborated with Peter Guthrie Tait
Peter Guthrie Tait
Peter Guthrie Tait FRSE was a Scottish mathematical physicist, best known for the seminal energy physics textbook Treatise on Natural Philosophy, which he co-wrote with Kelvin, and his early investigations into knot theory, which contributed to the eventual formation of topology as a mathematical...

 on a text book that unified the various branches of physical science under the common principle of energy. Published in 1867, the Treatise on Natural Philosophy
Treatise on Natural Philosophy
Treatise on Natural Philosophy was an 1867 text book by William Thomson and Peter Guthrie Tait, published by Oxford University Press, that did much to define the modern discipline of physics.-External links:* on Google books*...

did much to define the modern discipline of physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

.

Marine

Thomson was an enthusiastic yachtsman, his interest in all things relating to the sea perhaps arising, or at any rate fostered, from his experiences on the Agamemnon and the Great Eastern
SS Great Eastern
SS Great Eastern was an iron sailing steam ship designed by Isambard Kingdom Brunel, and built by J. Scott Russell & Co. at Millwall on the River Thames, London. She was by far the largest ship ever built at the time of her 1858 launch, and had the capacity to carry 4,000 passengers around the...

.

Thomson introduced a method of deep-sea sounding
Echo sounding
Echo sounding is the technique of using sound pulses directed from the surface or from a submarine vertically down to measure the distance to the bottom by means of sound waves. This information is then typically used for navigation purposes or in order to obtain depths for charting purposes...

, in which a steel piano wire
Piano wire
Piano wire, or "music wire", is a specialized type of wire made for use in piano strings, as well as many other purposes. It is made from tempered high-carbon steel, also known as spring steel.-Manufacture and use:...

 replaces the ordinary land line. The wire glides so easily to the bottom that "flying soundings" can be taken while the ship is going at full speed. A pressure gauge to register the depth of the sinker was added by Thomson.

About the same time he revived the Sumner method of finding a ship's place at sea, and calculated a set of tables for its ready application. He also developed a tide predicting machine.

During the 1880s, Thomson worked to perfect the adjustable compass
Compass
A compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined...

 in order to correct errors arising from magnetic deviation
Magnetic deviation
Magnetic deviation is the error induced in a compass by local magnetic fields, which must be allowed for, along with magnetic declination, if accurate bearings are to be calculated....

 owing to the increasing use of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 in naval architecture
Naval architecture
Naval architecture is an engineering discipline dealing with the design, construction, maintenance and operation of marine vessels and structures. Naval architecture involves basic and applied research, design, development, design evaluation and calculations during all stages of the life of a...

. Thomson's design was a great improvement on the older instruments, being steadier and less hampered by friction, the deviation due to the ship's own magnetism being corrected by movable masses of iron at the binnacle
Binnacle
A binnacle is a waist-high case or stand on the deck of a ship, generally mounted in front of the helmsman, in which navigational instruments are placed for easy and quick reference as well as to protect the delicate instruments. Its traditional purpose was to hold the ship's magnetic compass,...

. Thomson's innovations involved much detailed work to develop principles already identified by George Biddell Airy
George Biddell Airy
Sir George Biddell Airy PRS KCB was an English mathematician and astronomer, Astronomer Royal from 1835 to 1881...

 and others but contributed little in terms of novel physical thinking. Thomson's energetic lobbying and networking proved effective in gaining acceptance of his instrument by The Admiralty.
Charles Babbage
Charles Babbage
Charles Babbage, FRS was an English mathematician, philosopher, inventor and mechanical engineer who originated the concept of a programmable computer...

 had been among the first to suggest that a lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....

 might be made to signal a distinctive number by occultations of its light but Thomson pointed out the merits of the Morse code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...

 for the purpose, and urged that the signals should consist of short and long flashes of the light to represent the dots and dashes.

Electrical standards

Thomson did more than any other electrician up to his time in introducing accurate methods and apparatus for measuring electricity. As early as 1845 he pointed out that the experimental results of William Snow Harris
William Snow Harris
Sir William Snow Harris was an English physician and electrical researcher, nicknamed Thunder-and-Lightning Harris, and noted for his invention of a successful system of lightning conductors for ships...

 were in accordance with the laws of Coulomb
Charles-Augustin de Coulomb
Charles-Augustin de Coulomb was a French physicist. He is best known for developing Coulomb's law, the definition of the electrostatic force of attraction and repulsion. The [SI unit] of charge, the coulomb, was named after him....

. In the Memoirs of the Roman Academy of Sciences for 1857 he published a description of his new divided ring electrometer
Electrometer
An electrometer is an electrical instrument for measuring electric charge or electrical potential difference. There are many different types, ranging from historical hand-made mechanical instruments to high-precision electronic devices...

, based on the old electroscope of Johann Gottlieb Friedrich von Bohnenberger
Johann Gottlieb Friedrich von Bohnenberger
Johann Gottlieb Friedrich von Bohnenberger was born at Simmozheim, Württemberg. He studied at the University of Tübingen...

 and he introduced a chain or series of effective instruments, including the quadrant electrometer, which cover the entire field of electrostatic measurement. He invented the current balance, also known as the Kelvin balance or Ampere balance (SiC), for the precise
Accuracy and precision
In the fields of science, engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual value. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which...

 specification of the ampere
Ampere
The ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...

, the standard unit
Units of measurement
A unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of...

 of electric current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...

.

In 1893, Thomson headed an international commission to decide on the design of the Niagara Falls
Niagara Falls
The Niagara Falls, located on the Niagara River draining Lake Erie into Lake Ontario, is the collective name for the Horseshoe Falls and the adjacent American Falls along with the comparatively small Bridal Veil Falls, which combined form the highest flow rate of any waterfalls in the world and has...

 power station
Power station
A power station is an industrial facility for the generation of electric energy....

. Despite his previous belief in the superiority of direct current
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...

 electric power transmission
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...

, he was convinced by Nikola Tesla
Nikola Tesla
Nikola Tesla was a Serbian-American inventor, mechanical engineer, and electrical engineer...

's demonstration of three-phase alternating current
Alternating current
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....

 power transmission at the Chicago World's Fair
World's Columbian Exposition
The World's Columbian Exposition was a World's Fair held in Chicago in 1893 to celebrate the 400th anniversary of Christopher Columbus's arrival in the New World in 1492. Chicago bested New York City; Washington, D.C.; and St...

 of that year and agreed to use Tesla's system. In 1896, Thomson said "Tesla has contributed more to electrical science than any man up to his time."

Age of the Earth: Geology and theology

Thomson remained a devout believer in Christianity throughout his life; attendance at chapel was part of his daily routine, though writers such as H.I. Sharlin argue he might not identify with fundamentalism
Fundamentalism
Fundamentalism is strict adherence to specific theological doctrines usually understood as a reaction against Modernist theology. The term "fundamentalism" was originally coined by its supporters to describe a specific package of theological beliefs that developed into a movement within the...

 if he were alive today. He saw his Christian faith as supporting and informing his scientific work, as is evident from his address to the annual meeting of the Christian Evidence Society
Christian Evidence Society
The Christian Evidence Society is a UK Christian apologetics organisation founded in 1870. At its financial peak it had slightly over 400 paying members, but this declined to below 300 by 1897...

, 23 May 1889.

One of the clearest instances of this interaction is in his estimate of the age of the Earth
Age of the Earth
The age of the Earth is 4.54 billion years This age is based on evidence from radiometric age dating of meteorite material and is consistent with the ages of the oldest-known terrestrial and lunar samples...

. Given his youthful work on the figure of the Earth and his interest in heat conduction, it is no surprise that he chose to investigate the Earth's cooling and to make historical inferences of the Earth's age from his calculations. Thomson was a creationist
Creationism
Creationism is the religious beliefthat humanity, life, the Earth, and the universe are the creation of a supernatural being, most often referring to the Abrahamic god. As science developed from the 18th century onwards, various views developed which aimed to reconcile science with the Genesis...

 in a broad sense, but he was not a 'flood geologist
Flood geology
Flood geology is the interpretation of the geological history of the Earth in terms of the global flood described in Genesis 6–9. Similar views played a part in the early development of the science of geology, even after the Biblical chronology had been rejected by geologists in favour of an...

'. He contended that the laws of thermodynamics
Laws of thermodynamics
The four laws of thermodynamics summarize its most important facts. They define fundamental physical quantities, such as temperature, energy, and entropy, in order to describe thermodynamic systems. They also describe the transfer of energy as heat and work in thermodynamic processes...

 operated from the birth of the universe and envisaged a dynamic process that saw the organisation and evolution of the solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...

 and other structures, followed by a gradual "heat death". He developed the view that the Earth had once been too hot to support life
Life
Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not, either because such functions have ceased , or else because they lack such functions and are classified as inanimate...

 and contrasted this view with that of uniformitarianism
Uniformitarianism (science)
In the philosophy of naturalism, the uniformitarianism assumption is that the same natural laws and processes that operate in the universe now, have always operated in the universe in the past and apply everywhere in the universe. It has included the gradualistic concept that "the present is the...

, that conditions had remained constant since the indefinite past. He contended that "This earth, certainly a moderate number of millions of years ago, was a red-hot globe ... ."

After the publication of Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

's On the Origin of Species in 1859, Thomson saw evidence of the relatively short habitable age of the Earth as tending to contradict Darwin's gradualist explanation of slow natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

 bringing about biological diversity. Thomson's own views favoured a version of theistic evolution
Theistic evolution
Theistic evolution or evolutionary creation is a concept that asserts that classical religious teachings about God are compatible with the modern scientific understanding about biological evolution...

 sped up by divine guidance. His calculations showed that the sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 could not have possibly existed long enough to allow the slow incremental development by evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

 — unless some energy source beyond what he or any other Victorian era
Victorian era
The Victorian era of British history was the period of Queen Victoria's reign from 20 June 1837 until her death on 22 January 1901. It was a long period of peace, prosperity, refined sensibilities and national self-confidence...

 person knew of was found. He was soon drawn into public disagreement with geologists, and with Darwin's supporters John Tyndall
John Tyndall
John Tyndall FRS was a prominent Irish 19th century physicist. His initial scientific fame arose in the 1850s from his study of diamagnetism. Later he studied thermal radiation, and produced a number of discoveries about processes in the atmosphere...

 and T.H. Huxley. In his response to Huxley’s address to the Geological Society of London (1868) he presented his address "Of Geological Dynamics", (1869) which, among his other writings, challenged the geologists' acceptance that the earth must be of indefinite age.

Thomson’s initial 1864 estimate of the Earth’s age was from 20 to 400 million years old. These wide limits were due to his uncertainty about the melting temperature of rock, to which he equated the earth’s interior temperature. Over the years he refined his arguments and reduced the upper bound by a factor of ten, and in 1897 Thomson, now Lord Kelvin, ultimately settled on an estimate that the Earth was 20–40 million years old. His exploration of this estimate can be found in his 1897 address to the Victoria Institute
Victoria Institute
The Victoria Institute, or Philosophical Society of Great Britain, was founded in 1865, as a response to the publication of On the Origin of Species and Essays and Reviews. Its stated objective was to defend "the great truths revealed in Holy Scripture .....

, given at the request of the Institute's president George Stokes, as recorded in that Institute's journal Transactions
Science and Christian Belief
Science and Christian Belief is an academic journal published twice yearly by Christians in Science and the Victoria Institute. The journal focuses on the traffic of ideas between science and religion, with particular reference to Christianity...

. Although his former assistant John Perry
John Perry (engineer)
John Perry was a pioneering engineer and mathematician from Ireland. He was born on February 14, 1850 at Garvagh, County Londonderry, the second son of Samuel Perry and a Scottish-born wife....

 published a paper in 1895 challenging Kelvin's assumption of low thermal conductivity
Thermal conductivity
In physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....

 inside the Earth, and thus showing a much greater age, this had little immediate impact. The discovery in 1903 that radioactive decay
Radioactive decay
Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom...

 releases heat led to Kelvin's estimate being challenged, and Ernest Rutherford
Ernest Rutherford
Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

 famously made the argument in a lecture attended by Kelvin that this provided the unknown energy source Kelvin had suggested, but the estimate was not overturned until the development in 1907 of radiometric dating
Radiometric dating
Radiometric dating is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates...

 of rocks.

It was widely believed that the discovery of radioactivity had invalidated Thomson's estimate of the age of the Earth. Thomson himself never publicly acknowledged this because he had a much stronger argument restricting the age of the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 to no more than 20 million years. Without sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...

, there could be no explanation for the sediment record on the Earth's surface. At the time, the only known source for the solar power output was gravitational collapse
Gravitational collapse
Gravitational collapse is the inward fall of a body due to the influence of its own gravity. In any stable body, this gravitational force is counterbalanced by the internal pressure of the body, in the opposite direction to the force of gravity...

. It was only when thermonuclear fusion was recognized in the 1930's that Thomson's age paradox was truly resolved.

Later life and death

In the winter of 1860-1861 Kelvin slipped on some ice and fractured his leg, causing him to limp thereafter. He remained something of a celebrity on both sides of the Atlantic until his death.

Lord Kelvin was an Elder
Ministers and elders in the Church of Scotland
A Church of Scotland congregation is led by its minister and elders. Both of these terms are also used in other Christian denominations: see Minister and Elder...

 of St Columba's Parish Church (Church of Scotland
Church of Scotland
The Church of Scotland, known informally by its Scots language name, the Kirk, is a Presbyterian church, decisively shaped by the Scottish Reformation....

) in Largs for many years. It was to that church that his remains were taken after his death in 1907. Following the funeral service there, the body was taken to Bute Hall in his beloved University of Glasgow
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...

 for a service of remembrance before the body was taken to London for interment at Westminster Abbey
Westminster Abbey
The Collegiate Church of St Peter at Westminster, popularly known as Westminster Abbey, is a large, mainly Gothic church, in the City of Westminster, London, United Kingdom, located just to the west of the Palace of Westminster. It is the traditional place of coronation and burial site for English,...

, close-by the final resting place of Sir Isaac Newton.

Limits of classical physics

In 1884, Thomson delivered a series of lectures at Johns Hopkins University
Johns Hopkins University
The Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...

 in the United States in which he attempted to formulate a physical model for the aether
Luminiferous aether
In the late 19th century, luminiferous aether or ether, meaning light-bearing aether, was the term used to describe a medium for the propagation of light....

, a medium that would support the electromagnetic waves that were becoming increasingly important to the explanation of radiative
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

 phenomena. Imaginative as they were, the "Baltimore lectures" had little enduring value owing to the imminent demise of the mechanical world view.

In 1900, he gave a lecture titled Nineteenth-Century Clouds over the Dynamical Theory of Heat and Light. The two "dark clouds" he was alluding to were the unsatisfactory explanations that the physics of the time could give for two phenomena: the Michelson–Morley experiment and black body
Black body
A black body is an idealized physical body that absorbs all incident electromagnetic radiation. Because of this perfect absorptivity at all wavelengths, a black body is also the best possible emitter of thermal radiation, which it radiates incandescently in a characteristic, continuous spectrum...

 radiation. Two major physical theories were developed during the twentieth century starting from these issues: for the former, the Theory of relativity
Theory of relativity
The theory of relativity, or simply relativity, encompasses two theories of Albert Einstein: special relativity and general relativity. However, the word relativity is sometimes used in reference to Galilean invariance....

; for the second, quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...

. Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

, in 1905, published the so-called "Annus Mirabilis Papers
Annus Mirabilis Papers
The Annus Mirabilis papers are the papers of Albert Einstein published in the Annalen der Physik scientific journal in 1905. These four articles contributed substantially to the foundation of modern physics and changed views on space, time, and matter...

", one of which explained the photoelectric effect and was a foundation paper of quantum mechanics, another of which described special relativity
Special relativity
Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...

.

Pronouncements later proven to be false

Like many scientists, he did make some mistakes in predicting the future of technology.

Circa 1896, Lord Kelvin was initially skeptical of X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

s, and regarded their announcement as a hoax. However, this was before he saw Röntgen's evidence, after which he accepted the idea, and even had his own hand X-rayed in May 1896.

His forecast for practical aviation was negative. In 1896 he refused an invitation to join the Aeronautical Society, writing that "I have not the smallest molecule of faith in aerial navigation other than ballooning or of expectation of good results from any of the trials we hear of." And in a 1902 newspaper interview he predicted that "No balloon and no aeroplane will ever be practically successful."

The statement "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement" is given in a number of sources, but without citation. It is reputed to be Kelvin's remark made in an address to the British Association for the Advancement of Science (1900). It is often found quoted without any footnote giving the source. However, another author reports in a footnote that his search to document the quote failed to find any direct evidence supporting it. Very similar statements have been attributed to other physicists contemporary to Kelvin.

In 1898, Kelvin predicted that only 400 years of oxygen supply remained on the planet, due to the rate of burning combustibles. In his calculation, Kelvin assumed that photosynthesis was the only source of free oxygen; he did not know about the oxygen cycle
Oxygen cycle
The Oxygen cycle is the biogeochemical cycle that describes the movement of oxygen within its three main reservoirs: the atmosphere , the total content of biological matter within the biosphere , and the lithosphere...

.

Other work

A variety of physical phenomena and concepts with which Thomson is associated are named Kelvin:

Always active in industrial research and development
Research and development
The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...

, he was a Vice-President of the Kodak corporation.

Honours

  • Fellow of the Royal Society of Edinburgh, 1847.
  • Foreign member of the Royal Swedish Academy of Sciences
    Royal Swedish Academy of Sciences
    The Royal Swedish Academy of Sciences or Kungliga Vetenskapsakademien is one of the Royal Academies of Sweden. The Academy is an independent, non-governmental scientific organization which acts to promote the sciences, primarily the natural sciences and mathematics.The Academy was founded on 2...

    , 1851.
    • Keith Medal
      Keith Medal
      The Keith Medal is a prize awarded by the Royal Society of Edinburgh, Scotland's national academy, for a scientific paper published in the society's scientific journals, preference being given to a paper containing a discovery, either in mathematics or earth sciences.The medal was inaugurated in...

      , 1864.
    • Gunning Victoria Jubilee Prize, 1887.
    • President, 1873–1878, 1886–1890, 1895–1907.
  • Fellow of the Royal Society, 1851.
    • Royal Medal
      Royal Medal
      The Royal Medal, also known as The Queen's Medal, is a silver-gilt medal awarded each year by the Royal Society, two for "the most important contributions to the advancement of natural knowledge" and one for "distinguished contributions in the applied sciences" made within the Commonwealth of...

      , 1856.
    • Copley Medal
      Copley Medal
      The Copley Medal is an award given by the Royal Society of London for "outstanding achievements in research in any branch of science, and alternates between the physical sciences and the biological sciences"...

      , 1883.
    • President, 1890–1895.
  • Knight
    Knight
    A knight was a member of a class of lower nobility in the High Middle Ages.By the Late Middle Ages, the rank had become associated with the ideals of chivalry, a code of conduct for the perfect courtly Christian warrior....

    ed 1866.
  • Commander of the Imperial Order of the Rose
    Order of the Rose
    The Imperial Order of the Rose is an Brazilian order of chivalry, instituted by Emperor Pedro I of Brazil on 17 October 1829 to commemorate his marriage to Amélie of Leuchtenberg....

     (Brazil), 1873.
  • Commander of the Legion of Honor (France), 1881.
    • Grand Officer of the Legion of Honor, 1889.
  • Knight of the Prussian Order Pour le Mérite
    Pour le Mérite
    The Pour le Mérite, known informally as the Blue Max , was the Kingdom of Prussia's highest military order for German soldiers until the end of World War I....

    , 1884.
  • Commander of the Order of Leopold (Belgium), 1890.
  • Baron Kelvin, of Largs
    Largs
    Largs is a town on the Firth of Clyde in North Ayrshire, Scotland, about from Glasgow. The original name means "the slopes" in Scottish Gaelic....

     in the County of Ayr
    Ayrshire
    Ayrshire is a registration county, and former administrative county in south-west Scotland, United Kingdom, located on the shores of the Firth of Clyde. Its principal towns include Ayr, Kilmarnock and Irvine. The town of Troon on the coast has hosted the British Open Golf Championship twice in the...

    , 1892. The title derives from the River Kelvin
    River Kelvin
    The Kelvin rises on watershed of Scotland on the moor south east of the village of Banton, east of Kilsyth - . At almost 22 miles long, it initially flows south to Dullatur Bog where it falls into a man made trench and takes a ninety degree turn flowing west along the northern boundary of the bog...

    , which runs by the grounds of the University of Glasgow
    University of Glasgow
    The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...

    . His title died with him, as he was survived by neither heirs nor close relations.
  • Knight Grand Cross of the Victorian Order
    Royal Victorian Order
    The Royal Victorian Order is a dynastic order of knighthood and a house order of chivalry recognising distinguished personal service to the order's Sovereign, the reigning monarch of the Commonwealth realms, any members of her family, or any of her viceroys...

    , 1896.
  • One of the first members of the Order of Merit, 1902.
  • Privy Counsellor, 1902.
  • First international recipient of John Fritz Medal
    John Fritz Medal
    The John Fritz Medal is since 1902 yearly awarded by the American Association of Engineering Societies for "outstanding scientific or industrial achievements". The medal was created for Fritz's 80th birthday, who lived between 1822 and 1913.- Recipients :...

    , 1905.
  • Order of the First Class of the Sacred Treasure of Japan
    Order of the Sacred Treasure
    The is a Japanese Order, established on January 4, 1888 by Emperor Meiji of Japan as the Order of Meiji. It is awarded in eight classes . It is generally awarded for long and/or meritorious service and considered to be the lowest of the Japanese orders of merit...

    , 1901.
  • He is buried in Westminster Abbey
    Westminster Abbey
    The Collegiate Church of St Peter at Westminster, popularly known as Westminster Abbey, is a large, mainly Gothic church, in the City of Westminster, London, United Kingdom, located just to the west of the Palace of Westminster. It is the traditional place of coronation and burial site for English,...

    , London next to Isaac Newton
    Isaac Newton
    Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...

    .
  • Lord Kelvin was commemorated on the £20 note issued by the Clydesdale Bank
    Clydesdale Bank
    Clydesdale Bank is a commercial bank in Scotland, a subsidiary of the National Australia Bank Group. In Scotland, Clydesdale Bank is the third largest clearing bank, although it also retains a branch network in London and the north of England...

     in 1971; in the current issue of banknotes, his image appears on the bank's £100 note. He is shown holding his adjustable compass and in the background is a map of the transatlantic cable.
  • The town of Kelvin, Arizona
    Arizona
    Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

    , is named in his honour, as he was reputedly a large investor in the mining operations there.

See also

  • Kelvin sensing
    Four-terminal sensing
    Four-terminal sensing , 4-wire sensing, or 4-point probes method is an electrical impedance measuring technique that uses separate pairs of current-carrying and voltage-sensing electrodes to make more accurate measurements than traditional two-terminal sensing...

  • Kelvin equation
    Kelvin equation
    The Kelvin equation describes the change in vapour pressure due to a curved liquid/vapor interface with radius r . The Kelvin equation is used for determination of pore size distribution of a porous medium using adsorption porosimetry...

  • Weaire–Phelan structure for a solution to the Kelvin problem regarding partitioning space.

Kelvin's works

2nd edition, 1883. (reissued by Cambridge University Press
Cambridge University Press
Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

, 2009. ISBN 978-1-108-00537-1) (reissued by Cambridge University Press
Cambridge University Press
Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

, 2010. ISBN 978-1-108-01448-9) 2nd edition, 1879. (reissued by Cambridge University Press
Cambridge University Press
Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

, 2010. ISBN 978-1-108-00767-2)

External links

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