Ernest Rutherford - Biographical

Ernest Rutherford - Biographical

Ernest Rutherford was born on August 30, 1871, in Nelson, New Zealand, the fourth child and second son in a family of seven sons and five daughters. His father James Rutherford, a Scottish wheelwright, immigrated to New Zealand with Ernest's grandfather and the whole family in 1842. His mother, née Martha Thompson, was an English schoolteacher, who, with her widowed mother, also went to live there in 1855.

Ernest received his early education in Government schools and at the age of 16 entered Nelson Collegiate School. In 1889 he was awarded a University scholarship and he proceeded to the University of New Zealand, Wellington, where he entered Canterbury College*. He graduated M.A. in 1893 with a double first in Mathematics and Physical Science and he continued with research work at the College for a short time, receiving the B.Sc. degree the following year. That same year, 1894, he was awarded an 1851 Exhibition Science Scholarship, enabling him to go to Trinity College, Cambridge, as a research student at the Cavendish Laboratory under J.J. Thomson. In 1897 he was awarded the B.A. Research Degree and the Coutts-Trotter Studentship of Trinity College. An opportunity came when the Macdonald Chair of Physics at McGill University, Montreal, became vacant, and in 1898 he left for Canada to take up the post.

Rutherford returned to England in 1907 to become Langworthy Professor of Physics in the University of Manchester, succeeding Sir Arthur Schuster, and in 1919 he accepted an invitation to succeed Sir Joseph Thomson as Cavendish Professor of Physics at Cambridge. He also became Chairman of the Advisory Council, H.M. Government, Department of Scientific and Industrial Research; Professor of Natural Philosophy, Royal Institution, London; and Director of the Royal Society Mond Laboratory, Cambridge.

Rutherford's first researches, in New Zealand, were concerned with the magnetic properties of iron exposed to high-frequency oscillations, and his thesis was entitled Magnetization of Iron by High-Frequency Discharges. He was one of the first to design highly original experiments with high-frequency, alternating currents. His second paper, Magnetic Viscosity, was published in the Transactions of the New Zealand Institute (1896) and contains a description of a time-apparatus capable of measuring time intervals of a hundred-thousandth of a second.

On his arrival at Cambridge his talents were quickly recognized by Professor Thomson. During his first spell at the Cavendish Laboratory, he invented a detector for electromagnetic waves, an essential feature being an ingenious magnetizing coil containing tiny bundles of magnetized iron wire. He worked jointly with Thomson on the behaviour of the ions observed in gases which had been treated with X-rays, and also, in 1897, on the mobility of ions in relation to the strength of the electric field, and on related topics such as the photoelectric effect. In 1898 he reported the existence of alpha and beta rays in uranium radiation and indicated some of their properties.

In Montreal, there were ample opportunities for research at McGill, and his work on radioactive bodies, particularly on the emission of alpha rays, was continued in the Macdonald Laboratory. With R.B. Owens he studied the "emanation" of thorium and discovered a new noble gas, an isotope of radon, which was later to be known as thoron. Frederick Soddy arrived at McGill in 1900 from Oxford, and he collaborated with Rutherford in creating the "disintegration theory" of radioactivity which regards radioactive phenomena as atomic - not molecular - processes. The theory was supported by a large amount of experimental evidence, a number of new radioactive substances were discovered and their position in the series of transformations was fixed. Otto Hahn, who later discovered atomic fission, worked under Rutherford at the Montreal Laboratory in 1905-06.

At Manchester, Rutherford continued his research on the properties of the radium emanation and of the alpha rays and, in conjunction with H. Geiger, a method of detecting a single alpha particle and counting the number emitted from radium was devised. In 1910, his investigations into the scattering of alpha rays and the nature of the inner structure of the atom which caused such scattering led to the postulation of his concept of the "nucleus", his greatest contribution to physics. According to him practically the whole mass of the atom and at the same time all positive charge of the atom is concentrated in a minute space at the centre. In 1912 Niels Bohr joined him at Manchester and he adapted Rutherford's nuclear structure to Max Planck's quantum theory and so obtained a theory of atomic structure which, with later improvements, mainly as a result of Heisenberg's concepts, remains valid to this day. In 1913, together with H. G. Moseley, he used cathode rays to bombard atoms of various elements and showed that the inner structures correspond with a group of lines which characterize the elements. Each element could then be assigned an atomic number and, more important, the properties of each element could be defined by this number. In 1919, during his last year at Manchester, he discovered that the nuclei of certain light elements, such as nitrogen, could be "disintegrated" by the impact of energetic alpha particles coming from some radioactive source, and that during this process fast protons were emitted. Blackett later proved, with the cloud chamber, that the nitrogen in this process was actually transformed into an oxygen isotope, so that Rutherford was the first to deliberately transmute one element into another. G. de Hevesy was also one of Rutherford's collaborators at Manchester.

An inspiring leader of the Cavendish Laboratory, he steered numerous future Nobel Prize winners towards their great achievements: Chadwick, Blackett, Cockcroft and Walton; while other laureates worked with him at the Cavendish for shorter or longer periods: G.P. Thomson, Appleton, Powell, and Aston. C.D. Ellis, his co-author in 1919 and 1930, pointed out "that the majority of the experiments at the Cavendish were really started by Rutherford's direct or indirect suggestion". He remained active and working to the very end of his life.

Rutherford published several books: Radioactivity (1904); Radioactive Transformations (1906), being his Silliman Lectures at Yale University; Radiation from Radioactive Substances, with James Chadwick and C.D. Ellis (1919, 1930) - a thoroughly documented book which serves as a chronological list of his many papers to learned societies, etc.; The Electrical Structure of Matter (1926); The Artificial Transmutation of the Elements (1933); The Newer Alchemy (1937).

Rutherford was knighted in 1914; he was appointed to the Order of Merit in 1925, and in 1931 he was created First Baron Rutherford of Nelson, New Zealand, and Cambridge. He was elected Fellow of the Royal Society in 1903 and was its President from 1925 to 1930. Amongst his many honours, he was awarded the Rumford Medal (1905) and the Copley Medal (1922) of the Royal Society, the Bressa Prize (1910) of the Turin Academy of Science, the Albert Medal (1928) of the Royal Society of Arts, the Faraday Medal (1930) of the Institution of Electrical Engineers, the D.Sc. degree of the University of New Zealand, and honorary doctorates from the Universities of Pennsylvania, Wisconsin, McGill, Birmingham, Edinburgh, Melbourne, Yale, Glasgow, Giessen, Copenhagen, Cambridge, Dublin, Durham, Oxford, Liverpool, Toronto, Bristol, Cape Town, London and Leeds.

Rutherford married Mary Newton, only daughter of Arthur and Mary de Renzy Newton, in 1900. Their only child, Eileen, married the physicist R.H. Fowler. Rutherford's chief recreations were golf and motoring.

He died in Cambridge on October 19, 1937. His ashes were buried in the nave of Westminster Abbey, just west of Sir Isaac Newton's tomb and by that of Lord Kelvin.

From Nobel Lectures, Chemistry 1901-1921, Elsevier Publishing Company, Amsterdam, 1966

This autobiography/biography was written at the time of the award and first published in the book series Les Prix Nobel. It was later edited and republished in Nobel Lectures. To cite this document, always state the source as shown above.

* Canterbury College (now Canterbury University) was located in Christchurch, but was administered from the University of New Zealand, Wellington.

William Thomson Kelvin

William Thomson, 1st Baron Kelvin

      William Thomson, 1st Baron Kelvin OM GCVO PC PRS FRSE (/ˈkɛlvɪn/; 26 June 1824 – 17 December 1907) was an Irish mathematical physicist and engineer who was born in Belfast in 1824. At the University of Glasgow he did important work in the mathematical analysis of electricity and formulation of the first and second laws of thermodynamics, and did much to unify the emerging discipline of physics in its modern form. He worked closely with mathematics professor Hugh Blackburn 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 honour. For his work on the transatlantic telegraph project he was knighted by Queen Victoria, 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.

Absolute temperatures are stated in units of kelvin in his honour. While the existence of a lower limit to temperature (absolute zero) was known prior to his work, Lord Kelvin is widely known for determining its correct value as approximately −273.15 degree Celsius or −459.67 degree Fahrenheit.

He was ennobled in 1892 in recognition of his achievements in thermodynamics, and of his opposition to Irish Home Rule, becoming Baron Kelvin, of Largs in the County of Ayr. He was the first British scientist to be elevated to the House of Lords. The title refers to the River Kelvin, which flows close by his laboratory at the University of Glasgow. His home was the imposing red sandstone mansion Netherhall, in Largs. 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 has a permanent exhibition on the work of Lord Kelvin including many of his original papers, instruments and other artefacts such as his smoking pipe.

Always active in industrial research and development, he was recruited around 1899 by George Eastman to serve as vice-chairman of the board of the British company Kodak Limited, affiliated with Eastman Kodak.

Early life and work

Family

William Thomson's father, James Thomson, was a teacher of mathematics and engineering at Royal Belfast Academical Institution 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 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.

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.

His sister, Anna Thomson, was the mother of James Thomson Bottomley FRSE (1845-1926).

Youth

Thomson had heart problems and nearly died when he was 9 years old. He attended the Royal Belfast Academical Institution, 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 to English.

In the academic year 1839/1840, Thomson won the class prize in astronomy 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 strategy during times of personal stress. On the title page of this essay Thomson wrote the following lines from Alexander Pope's Essay on Man. These lines inspired Thomson to understand the natural world using the power and method of science:

Go, wondrous creature! mount where Science guides;

Go measure earth, weigh air, and state the tides;

Instruct the planets in what orbs to run,

Correct old Time, and regulate the sun;

Thomson became intrigued with Fourier's 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. Unsurprisingly, Fourier's work had been attacked by domestic mathematicians, Philip Kelland authoring a critical book. The book motivated Thomson to write his first published scientific paper under the pseudonym 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 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 and electrostatics, an analogy that James Clerk Maxwell 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. In 1845 Thomson graduated as Second Wrangler. He also won a Smith's Prize, which, unlike the tripos, is a test of original research. Robert Leslie Ellis, 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, 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, physics, and in particular, of electricity, had captivated his imagination.

Lord Kelvin by Hubert von Herkomer

In 1845, he gave the first mathematical development of Faraday'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 the mathematical technique of electrical images, which became a powerful agent in solving problems of electrostatics, the science which deals with the forces between electrically charged bodies 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, which established that light and magnetic (and thus electric) phenomena were related.

He was elected a fellow of St. Peter's (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, at Paris; but in 1846 he was appointed to the chair of natural philosophy in the University of Glasgow. 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 first year student 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 annual meeting in Oxford. At that meeting, he heard James Prescott Joule making yet another of his, so far, ineffective attempts to discredit the caloric theory of heat and the theory of the heat engine built upon it by Sadi Carnot and Émile Clapeyron. Joule argued for the mutual convertibility of heat and mechanical work and for their mechanical equivalence.

Thomson was intrigued but sceptical. 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 of ice must fall with pressure, otherwise its expansion on freezing could be exploited in a perpetuum mobile. 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 provided only an operational definition 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 about which Guillaume Amontons had speculated in 1702. "Reflections on the Motive Power of Heat", published by Carnot in French in 1824, the year of Lord Kelvin's birth, used −267 as an estimate of the absolute zero temperature. Thomson used data published by Regnault to calibrate his scale against established measurements.

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 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. 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 beliefs led to speculation about the heat death of the universe.

I believe the tendency in the material world is for motion to become diffused, and that as a whole the reverse of concentration is gradually going on – I believe that no physical action can ever restore the heat emitted from the Sun, and that this source is not inexhaustible; also that the motions of the Earth and other planets are losing vis viva which is converted into heat; and that although some vis viva may be restored for instance to the earth by heat received from the sun, or by other means, that the loss cannot be precisely compensated and I think it probable that it is under compensated.

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:

It is impossible, by means of inanimate material agency, to derive mechanical effect from any portion of matter by cooling it below the temperature of the coldest of the surrounding objects.

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 and the experiments of Joule and Julius Robert von Mayer, 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, 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.

Thomson published more than 650 scientific papers and applied for 70 patents (not all were issued). Regarding science, Thomson wrote the following.

In physical science a first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it. I often say that when you can measure what you are speaking about and express it in numbers you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind: it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.

Transatlantic cable

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 Walter Crum; 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 wrote to Thomson to try to re-interest him in work by asking his opinion on some experiments of Michael Faraday on the proposed transatlantic telegraph cable.

Faraday had demonstrated how the construction of a cable would limit the rate at which messages could be sent – in modern terms, the bandwidth. Thomson jumped at the problem and published his response that month. He expressed his results in terms of the data rate that could be achieved and the economic consequences in terms of the potential revenue of the transatlantic undertaking. In a further 1855 analysis,Thomson stressed the impact that the design of the cable would have on its profitability.

Thomson contended that the speed[clarification needed] of a signal through a given core[clarification needed] 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, the electrician of the Atlantic Telegraph Company. 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 magazine,pitching himself into the public eye. Thomson recommended a larger conductor with a larger cross section of 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 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 as chief engineer but Whitehouse had his way with the specification, supported by Faraday and Samuel F. B. Morse.

Thomson sailed on board the cable-laying ship HMS Agamemnon in August 1857, with Whitehouse confined to land owing to illness, but the voyage ended after 380 miles (610 km) when the cable parted. Thomson contributed to the effort by publishing in the Engineer the whole theory of the stresses involved in the laying of a submarine cable, 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 every 3.5 seconds. He patented the key elements of his system, the mirror galvanometer and the siphon recorder, 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 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 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 realized when 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. 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 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, 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 SS Great Eastern but the voyage was again dogged by technical problems. The cable was lost after 1,200 miles (1,900 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. In conjunction with the latter, he also devised an automatic curb sender, a kind of telegraph key for sending messages on a cable.

Later expeditions

Thomson took part in the laying of the French Atlantic submarine communications cable of 1869, and with Jenkin was engineer of the Western and Brazilian and Platino-Brazilian cables, assisted by vacation student James Alfred Ewing. He was present at the laying of the Pará to Pernambuco 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, 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 HMS Captain.

In June 1873, Thomson and Jenkin were on board the Hooper, bound for Lisbon with 2,500 miles (4,020 km) of cable when the cable developed a fault. An unscheduled 16-day stop-over in Madeira 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 on a text book that founded the study of mechanics first on the mathematics of kinematics, the description of motion without regard to force. The text developed dynamics in various areas but with constant attention to energy as a unifying principle.

A second edition appeared in 1879, expanded to two separately bound parts. The textbook set a standard for early education in mathematical physics.

Kelvin's vortex theory of the atom

Between 1870 and 1890 a theory purporting that an atom was a vortex in the ether was immensely popular among British physicists and mathematicians. About 60 scientific papers were written by around 25 scientists. Following the lead of Thomson and Tait, the branch of topology called knot theory was developed. Kelvin's initiative in this complex study that continues to inspire new mathematics has led to persistence of the topic in history of science.

Marine

Thomson's tide-predicting machine

Thomson was an enthusiastic yachtsman, his interest in all things relating to the sea perhaps arising from, or at any rate fostered by, his experiences on the Agamemnon and the Great Eastern.

Thomson introduced a method of deep-sea sounding, in which a steel piano wire replaces the ordinary hand 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 in order to correct errors arising from magnetic deviation owing to the increasing use of iron in naval architecture. 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. Thomson's innovations involved much detailed work to develop principles already identified by George Biddell Airy 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.

Scientific biographers of Thomson, if they have paid any attention at all to his compass innovations, have generally taken the matter to be a sorry saga of dim-witted naval administrators resisting marvellous innovations from a superlative scientific mind. Writers sympathetic to the Navy, on the other hand, portray Thomson as a man of undoubted talent and enthusiasm, with some genuine knowledge of the sea, who managed to parlay a handful of modest ideas in compass design into a commercial monopoly for his own manufacturing concern, using his reputation as a bludgeon in the law courts to beat down even small claims of originality from others, and persuading the Admiralty and the law to overlook both the deficiencies of his own design and the virtues of his competitors'.

The truth, inevitably, seems to lie somewhere between the two extremes.

Charles Babbage had been among the first to suggest that a lighthouse might be made to signal a distinctive number by occultations of its light but Thomson pointed out the merits of the Morse code 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 were in accordance with the laws of Coulomb. In the Memoirs of the Roman Academy of Sciences for 1857 he published a description of his new divided ring electrometer, based on the old electroscope of Johann Gottlieb Friedrich von Bohnenberger 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 specification of the ampere, the standard unit of electric current.

In 1893, Thomson headed an international commission to decide on the design of the Niagara Falls power station. Despite his belief in the superiority of direct current electric power transmission, he endorsed Westinghouse's alternating current system which had been demonstrated at the Chicago World's Fair of that year. Even after Niagara Falls Thomson still held to his belief that direct current was the superior system.

Acknowledging his contribution to electrical standardisation, the International Electrotechnical Commission elected Thomson as its first President at its preliminary meeting, held in London on 26–27 June 1906. "On the proposal of the President [Mr Alexander Siemens, Great Britain], secounded [sic] by Mr Mailloux [US Institute of Electrical Engineers] the Right Honorable Lord Kelvin, G.C.V.O., O.M., was unanimously elected first President of the Commission", minutes of the Preliminary Meeting Report read.

Age of the Earth: geology and theology

Lord Kelvin caricatured by Spy for Vanity Fair, 1897

Thomson remained a devout believer in Christianity throughout his life; attendance at chapel was part of his daily routine. 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, 23 May 1889.

One of the clearest instances of this interaction is in his estimate of the age of the Earth. 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 in a broad sense, but he was not a 'flood geologist'.He contended that the laws of thermodynamics operated from the birth of the universe and envisaged a dynamic process that saw the organisation and evolution of the solar system and other structures, followed by a gradual "heat death". He developed the view that the Earth had once been too hot to support life and contrasted this view with that of uniformitarianism, 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'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 bringing about biological diversity. Thomson's own views favoured a version of theistic evolution sped up by divine guidance.His calculations showed that the Sun could not have possibly existed long enough to allow the slow incremental development by evolution – unless some energy source beyond what he or any other Victorian era person knew of was found. He was soon drawn into public disagreement with geologists, and with Darwin's supporters John Tyndall 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, given at the request of the Institute's president George Stokes, as recorded in that Institute's journal Transactions. Although his former assistant John Perry published a paper in 1895 challenging Kelvin's assumption of low thermal conductivity inside the Earth, and thus showing a much greater age, this had little immediate impact. The discovery in 1903 that radioactive decay releases heat led to Kelvin's estimate being challenged, and Ernest Rutherford 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 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 thought he had a much stronger argument restricting the age of the Sun to no more than 20 million years. Without sunlight, 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. It was only when thermonuclear fusion was recognised in the 1930s that Thomson's age paradox was truly resolved.

Later life and death

Statue of Lord Kelvin; Belfast Botanic Gardens

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.

In November 1907 he caught a chill and his condition deteriorated until he died at his Scottish residence, Netherhall, in Largs on 17 December.

Lord Kelvin was an elder of St Columba's Parish Church (Church of Scotland) in Largs for many years. It was to that church that his remains were taken after his death at Largs on 17 December 1907. Following the funeral service there, the body was taken to Bute Hall in his beloved University of Glasgow for a service of remembrance before the body was taken to London for interment at Westminster Abbey, near the final resting place of Sir Isaac Newton.

Limits of classical physics

In 1884, Thomson led a master class on "Molecular Dynamics and the Wave Theory of Light" at Johns Hopkins University.Kelvin referred to the acoustic wave equation describing sound as waves of pressure in air and attempted to describe also an electromagnetic wave equation, presuming a luminiferous aether susceptible to vibration. The study group included Michelson and Morley who subsequently performed the Michelson-Morley experiment that undercut the aether theory. Thomson did not provide a text but A. S. Hathaway took notes and duplicated them with a Papyrograph. As the subject matter was under active development, Thomson amended that text and in 1904 it was typeset and published. Thomson's attempts to provide mechanical models ultimately failed in the electromagnetic regime.

In 1900, on April 27 he gave a widely reported lecture titled Nineteenth-Century Clouds over the Dynamical Theory of Heat and Light to the Royal Institution. 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 radiation. Two major physical theories were developed during the twentieth century starting from these issues: for the former, the theory of relativity; for the second, quantum mechanics. Albert Einstein, in 1905, published the so-called "Annus Mirabilis papers", one of which explained the photoelectric effect and was a foundation paper of quantum mechanics, another of which described special relativity.

Pronouncements later proven to be false

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

His biographer Silvanus P. Thompson writes that "When Röntgen's discovery of the X-rays was announced at the end of 1895, Lord Kelvin was entirely sceptical, and regarded the announcement as a hoax...The papers had been full of the wonders of Röntgen's rays, about which Lord Kelvin was intensely sceptical until Röntgen himself sent him a copy of his Memoir"; on 17 January 1896, having read the paper & seen the photographs, he wrote Röntgen a letter saying that "I need not tell you that when I read the paper I was very much astonished and delighted. I can say no more now than to congratulate you warmly on the great discovery you have made"He would have his own hand X-rayed in May 1896. (See also N rays.)

His forecast for practical aviation (i.e., heavier-than-air aircraft) 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" has been widely misattributed to Kelvin since the 1980s, either without citation or stating that it was made in an address to the British Association for the Advancement of Science (1900). There is no evidence that Kelvin said this,and the quote is instead a paraphrase of Albert A. Michelson, who in 1894 stated: "… it seems probable that most of the grand underlying principles have been firmly established … An eminent physicist remarked that the future truths of physical science are to be looked for in the sixth place of decimals." Similar statements were given earlier by others, such as Philipp von Jolly.The attribution to Kelvin giving an address in 1900 is presumably a confusion with his "Two clouds" speech, delivered to the Royal Institution in 1900 (see above), and which on the contrary pointed out areas that would subsequently see revolutions.

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 all of the components of the oxygen cycle.[dubious – discuss] He could not even have known all of the sources of photosynthesis: for example the cyanobacterium Prochlorococcus—which accounts for more than half of marine photosynthesis—was not discovered until 1986.

James Clerk Maxwell (1831-1879)

Who was James Clerk Maxwell?

           James Clerk Maxwell (1831-1879) was one of the greatest scientists who have ever lived.  To him we owe the most significant discovery of our age - the theory of electromagnetism.  He is rightly acclaimed as the father of modern physics. He also made fundamental contributions to mathematics, astronomy and engineering.

Albert Einstein said: "The special theory of relativity owes its origins to Maxwell's equations of the electromagnetic field."
Einstein also said: "Since Maxwell's time, physical reality has been thought of as represented by continuous fields, and not capable of any mechanical interpretation.  This change in the conception of reality is the most profound and the most fruitful that physics has experienced since the time of Newton"

Ivan Tolstoy, in his biography of Maxwell, wrote: “Maxwell's importance in the history of scientific thought is comparable to Einstein’s (whom he inspired) and to Newton’s (whose influence he curtailed)”

Maxwell said, in 'A Dynamic Theory of the Electro-Magnetic Field' given to the Royal Society in 1864: “We have strong reason to conclude that light itself - including radiant heat and other radiation, if any - is an electromagnetic disturbance in the form of waves propagated through the electro-magnetic field according to electro-magnetic laws.”

On which Professor R V Jones commented: “This paper is the first pointer to the existence of radiation other than light and heat, and ranks as one of the greatest leaps ever achieved in human thought.”

"He achieved greatness unequalled"  Max Planck
                                                                                         
"From a long view of the history of mankind - seen from, say, ten thousand years from now - there can be little doubt that the most significant event of the 19th century will be judged as Maxwell's discovery of the laws of electrodynamics"  Richard P Feynman

Facts about James Clerk Maxwell

On the 13th June 1831 James Clerk Maxwell was born in Edinburgh, at 14 India Street, a house built for his father in that part of Edinburgh's elegant Georgian New Town which was developed after the Napoleonic Wars.  Although the family moved to their estate at Glenlair, near Dumfries, shortly afterwards, James returned to Edinburgh to attend school at The Edinburgh Academy.  He continued his education at the Universities of Edinburgh and Cambridge.  In 1856, at the early age of 25, he became Professor of Physics at Marischal College, Aberdeen. From there he moved first to King's College, London, and then, in 1871, to become the first Professor of Experimental Physics at Cambridge where he directed the newly created Cavendish Laboratory.  It was at the Cavendish, over the next fifty years, that so much of the physics of today continued to develop from Maxwell's inspiration. 

Modern technology, in large part, stems from his grasp of the basic principles of the universe.  Wide ranging developments in the field of electricity and electronics, including radio, television, radar and communications, derive from Maxwell's discovery of the laws of the electromagnetic field - which was not a synthesis of what was known before, but rather a fundamental change in concept that departed from Newton's view and was to influence greatly the modern scientific and industrial revolution.

Key dates in the life of  of James Clerk Maxwell

• 1831Born 13 June, 14 India Street
• 1833Moved to Glenlair
• 1841Enrolled, Edinburgh Academy
• 1846Maxwell’s first paper “On the description of oval curves and those having a plurality of foci” Proc Roy Soc Edinburgh, Vol. II
• 1847-50Studied, University of Edinburgh
• 1850Entered Peterhouse College, Cambridge - after one term migrated to Trinity College
• 1854Mathematical Tripos – 2nd Wrangler and First (Equal) Smith’s Prizeman
• 1856-60Appointed Professor of Natural Philosophy  at Marischal College, Aberdeen
• 1856Elected Fellow Royal Society Edinburgh (FRSE) aged 24
• 1857Essay on “The Stability of Saturn’s Rings” won the Adams Prize, University of Cambridge
• 1858Marriage to Katherine Mary Dewar on 2 June, Old Machar, Aberdeen
• 1860Paper “Illustrations of the Dynamical Theory of Gasses” where the Maxwell-Bolzman distribution for velocities in a gas are derived
• 1860-65Appointed Professor of Natural Philosophy at Kings College, London
• 1860Awarded Rumford Medal, Royal Society
• 1861Royal Institution, first demonstration on colour reproduction
• 1861Elected Fellow Royal Society (FRS) shortly before 30th birthday
• 1861/2“On physical lines of force”, Phil. Mag. Vols. 21 & 23. Calculates that electric and magnetic effects travel at speed of light and states “..we can scarcely avoid the inference that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena.”
• 1864Famous oral presentation: “Dynamical theory of the electromagnetic field” presented to Royal Society containing ‘Maxwell’s Equations’ states “.. that it seems we have strong reason to conclude that light itself (including radiant heat and other radiations if any) is an electromagnetic disturbance in the form of waves propagated ……according to the electromagnetic laws”
• 1865Above paper, “Dynamical theory of the electromagnetic field”, formally published in Phil. Trans. Roy. Soc., Vol. CLV,  London
• 1866Bakerian Lecture of the Royal Society: “On the viscosity or internal friction of air and other gases”, Phil. Trans. Roy. Soc. (Vol. CLVI) London. Includes measurements made in his London attic
• 1868“On a method of making a direct comparison of electrostatic with electromagnetic force; with a note on the electromagnetic theory of light”, Phil. Trans. Roy. Soc.  (Vol. CLVIII) London,  Includes consequence of definitions of electromagnetic and electrostatic units of electric charge which makes their ratio equal to the speed of light
• 1868“On governors”, Proc. Roy. Soc. (Vol. XVI) London. First mathematical treatment of feedback leading to control theory and cybernetics 
• 1869Awarded Keith Prize, Royal Society of Edinburgh
• 1870“On reciprocal figures, frames and diagrams of forces”, Trans. Roy. Soc. Edinburgh Vol. 26.  This follow-up to a paper by G B Airy on elasticity led to award (see above) of RSE Keith Medal 
• 1870“On hills and dales”, Phil. Mag. Vol. 40. An early contribution to the mathematics of topology
• 1870Awarded Doctor of Law (LLD), University of Edinburgh
• 1870Awarded Hopkins Prize, University of Cambridge
• 1870Published his textbook “Theory of Heat”
• 1871Directed and established Cavendish Laboratory, Cambridge, as First Professor of Experimental Physics
• 1871Second lecture on colour at Royal Institution: “On colour vision”
• 1873Publication of his “Treatise on Electricity and Magnetism“, Oxford University Press
• 1874Elected Foreign Honorary Member, American Academy of Arts and Sciences, Boston
• 1875Elected Member of American Philosophical Society of Philadelphia
• 1875Elected Corresponding Member, Royal Society of Sciences of Göttingen
• 1876Awarded Doctor of Civil Law (DCL), University of Oxford
• 1876Elected Honorary Member, New York Academy of Sciences
• 1877Published book ‘Matter and Motion’
• 1877Elected Member, Royal Academy of Sciences of Amsterdam
• 1877Elected Foreign Corresponding Member, Mathematico-Natural-Science Class of the Imperial Academy of Sciences of Vienna
• 1878Delivers Rede Lecture at Cambridge: “The Telephone”
• 1878Volta Medal, Doctor of Sciences honoris causa, University of Pavia
• 1879Dies of stomach cancer on 5 November, Cambridge.  Buried in Parton, Castle Douglas, Galloway.
• 2008Edinburgh statue unveiled on 25 November

The Impact of Maxwell’s Work

COMMUNICATIONS:
In the early nineteenth century, despite many individual advances in knowledge, there was no inkling of a comprehensive theory of electricity and magnetism. In developing this, Maxwell pointed the way to the existence of the spectrum of electromagnetic radiation. Defining fields as a tension in the medium, he stated his belief in a new concept - that energies resides in fields as well as bodies. This pointed the way to the application of electromagnetic radiation for such present-day uses as radio, television, radar, microwaves and thermal imaging.


THERMODYNAMICS:
Maxwell made fundamental contributions to the development of thermodynamics. He was also a founder of the kinetic theory of gases. This theory provided the new subject of statistical physics, linking thermodynamics and mechanics, and is still widely used as a model for rarefied gases and plasmas.

SPACE EXPLORATION:
The discovery of electromagnetic radiation led to the development of radio and infra-red telescopes, currently exploring the farthest reaches of space. His brilliant theoretical study of Saturn's rings provided a physical explanation, recently confirmed by a space probe vehicle.


RHEOLOGY:
This is concerned with the investigation and interpretation of the flow behaviour of substances.
It has many roles, extending to quality control, across industry (including the food industry) and in medicine. It can be traced back directly to Maxwell's pioneering theoretical and experimental work on topics, such as viscosity, which are strongly dependent on the molecular structure of free-flowing substances.

PHOTOGRAPHY:
He analysed the phenomenon of colour perception, which led him to invent the trichromatic process.

Using red, green and blue filters, he produced the first colour photography - of a Scottish tartan ribbon. This process (for which we have a short demonstration) was the forerunner of today's modern colour photography.


ENGINEERING:
Maxwell was the first to show how to calculate stresses in framed arch and suspension bridges. He also led the work of the British Association committee which defined most of the electrical units in use today; in the associated experiments he pioneered the use of feedback control.


MATHEMATICS:
His particular gift was the ability to see phenomena in terms of relationships which could be defined by equations, if necessary abandoning a physical analogy. He invented the term "curl" for the vector operator that appears in his equations for the electromagnetic field.


NUCLEAR ENERGY:
Calculating the speed of electromagnetic waves, Maxwell postulated that light is a form of electromagnetic radiation exerting pressure and carrying momentum. This provided the basis for Einstein's work on relativity from which the relationship between energy, mass and velocity contributed to the theory underlying the development of atomic energy.

Louis Pasteur

Louis Pasteur 

Chemist, Scientist, Inventor (1822–1895)

Louis Pasteur - Mini Biography (TV-PG; 3:17) Scientist Louis Pasteur came up with the food preparing process known as pasteurization, where bacteria is destroyed by heating beverages and allowing them to cool. His work in germ theory also led to vaccinations for anthrax and rabies.

Synopsis

Born on December 27, 1822, in Dole, France, Louis Pasteur discovered that microbes were responsible for souring alcohol and came up with the process of pasteurization, where bacteria is destroyed by heating beverages and then allowing them to cool. His work in germ theory also led him and his team to create vaccinations for anthrax and rabies.

Early Life

French chemist and microbiologist Louis Pasteur was born on December 27, 1822, in Dole, located in the Jura region of France. He grew up in the town of Arbois, and his father, Jean-Joseph Pasteur, was a tanner and a sergeant major decorated with the Legion of Honor during the Napoleonic Wars. An average student, Pasteur was skilled at drawing and painting. He earned his bachelor of arts degree (1840) and bachelor of science degree (1842) at the Royal College of Besançon and a doctorate (1847) from the École Normale in Paris.

Pasteur then spent several years researching and teaching at Dijon Lycée. In 1848, he became a professor of chemistry at the University of Strasbourg, where he met Marie Laurent, the daughter of the university's rector. They wed on May 29, 1849, and had five children, though only two survived childhood.

First Major Contribution in Chemistry

In 1849, Louis Pasteur was attempting to resolve a problem concerning the nature of tartaric acid—a chemical found in the sediments of fermenting wine. Scientists were using the rotation of polarized light as a means for studying crystals. When polarized light is passed through a solution of dissolved tartaric acid, the angle of the plane of light is rotated. Pasteur observed that another compound called paratartaric acid, also found in wine sediments, had the same composition as tartaric acid. Most scientists assumed the two compounds were identical. However, Pasteur observed that paratartaric acid did not rotate plane-polarized light. He deduced that although the two compounds had the same chemical composition, they must somehow have different structures.

Looking at the partartaric acid under a microscope, Pasteur observed there were two different types of tiny crystals. Though they looked almost identical, the two were actually mirror images of each other. He separated the two types of crystals into two piles and made solutions of each. When polarized light was passed through each, he discovered that both solutions rotated, but in opposite directions. When the two crystals were together in the solution the effect of polarized light was canceled. This experiment established that just studying the composition is not enough to understand how a chemical behaves. The structure and shape is also important and led to the field of stereochemistry.

Commercial Success

In 1854, Pasteur was appointed professor of chemistry and dean of the science faculty at the University of Lille. There, he worked on finding solutions to the problems with the manufacture of alcoholic drinks. Working with the germ theory, which Pasteur did not invent but further developed through experiments and eventually convinced most of Europe of its truth, he demonstrated that organisms such as bacteria were responsible for souring wine, beer and even milk. He then invented a process where bacteria could be removed by boiling and then cooling liquid. He completed the first test on April 20, 1862. Today the process is known as pasteurization.

Shifting focus, in 1865, Pasteur helped save the silk industry. He proved that microbes were attacking healthy silkworm eggs, causing an unknown disease, and that the disease would be eliminated if the microbes were eliminated. He eventually developed a method to prevent their contamination and it was soon used by silk producers throughout the world.

Pasteur's first vaccine discovery was in 1879, with a disease called chicken cholera. After accidentally exposing chickens to the attenuated form of a culture, he demonstrated that they became resistant to the actual virus. Pasteur went on to extend his germ theory to develop causes and vaccinations for diseases such as anthrax, cholera, TB and smallpox.

In 1873, Pasteur was elected as an associate member of the Académie de Médecine. In 1882, the year of his acceptance into the Académie Française, he decided to focus his efforts on the problem of rabies. On July 6, 1885, Pasteur vaccinated Joseph Meister, a 9-year-old boy who had been bitten by a rabid dog. The success of Pasteur's vaccine brought him immediate fame. This began an international fundraising campaign to build the Pasteur Institute in Paris, which was inaugurated on November 14, 1888.

Personal Life

Pasteur had been partially paralyzed since 1868, due to a severe brain stroke, but he was able to continue his research. He celebrated his 70th birthday at the Sorbonne, which was attended by several prominent scientists, including British surgeon Joseph Lister. At that time, his paralysis worsened, and he died on September 28, 1895. Pasteur's remains were transferred to a Neo-Byzantine crypt at the Pasteur Institute in 1896.

Charles Robert Darwin

Charles Robert Darwin
Born    :Charles Robert Darwin
                   12 February 1809
                   The Mount, Shrewsbury, Shropshire, England
Died            :19 April 1882 (aged 73)
                    Down House, Kent, England
Residence   :England
Citizenship  :British subject
Nationality  :British
Fields      :Natural history, Geology
Institutions   :Tertiary education:
                      University of Edinburgh Medical School (medicine)
                      Christ's College, Cambridge (University of Cambridge) (BA)
Professional institution:
                      Geological Society of London
                     Academic advisors John Stevens Henslow
                    Adam Sedgwick
 Known for:The Voyage of the Beagle
                     On the Origin of Species
                     evolution by
                      natural selection,
                      common descent
Influences     :Alexander von Humboldt
                       John Herschel
                       Charles Lyell
Influenced      :Joseph Dalton Hooker
                      Thomas Henry Huxley
                      George Romanes
                      Ernst Haeckel
                      Sir John Lubbock
                      Notable awards
                      FRS (1839)
                      Royal Medal (1853)
                    Wollaston Medal (1859)
                    Copley Medal (1864)
Spouse     :Emma Darwin (m. 1839)
Children    :10 children (see list)

Early life and education
See also: Charles Darwin's education and Darwin-Wedgwood family

Charles Robert Darwin was born in Shrewsbury, Shropshire, England, on 12 February 1809 at his family's home, The Mount.He was the fifth of six children of wealthy society doctor and financier Robert Darwin, and of Susannah Darwin (née Wedgwood). He was the grandson of two prominent abolitionists: Erasmus Darwin on his father's side, and Josiah Wedgwood on his mother's side.

Three quarter length portrait of seated boy smiling and looking at the viewer. He has straight mid-brown hair, and wears dark clothes with a large frilly white collar. In his lap he holds a pot of flowering plants

Painting of seven-year-old Charles Darwin in 1816.

Both families were largely Unitarian, though the Wedgwoods were adopting Anglicanism. Robert Darwin, himself quietly a freethinker, had baby Charles baptised in November 1809 in the Anglican St Chad's Church, Shrewsbury, but Charles and his siblings attended the Unitarian chapel with their mother. The eight-year-old Charles already had a taste for natural history and collecting when he joined the day school run by its preacher in 1817. That July, his mother died. From September 1818, he joined his older brother Erasmus attending the nearby Anglican Shrewsbury School as a boarder.

Darwin spent the summer of 1825 as an apprentice doctor, helping his father treat the poor of Shropshire, before going to the University of Edinburgh Medical School (at the time the best medical school in the UK) with his brother Erasmus in October 1825. He found lectures dull and surgery distressing, so neglected his studies. He learned taxidermy from John Edmonstone, a freed black slave who had accompanied Charles Waterton in the South American rainforest, and often sat with this "very pleasant and intelligent man".

In Darwin's second year at the university he joined the Plinian Society, a student natural-history group featuring lively debates in which radical democratic students with materialistic views challenged orthodox religious concepts of science. He assisted Robert Edmond Grant's investigations of the anatomy and life cycle of marine invertebrates in the Firth of Forth, and on 27 March 1827 presented at the Plinian his own discovery that black spores found in oyster shells were the eggs of a skate leech. One day, Grant praised Lamarck's evolutionary ideas. Darwin was astonished by Grant's audacity, but had recently read similar ideas in his grandfather Erasmus' journals. Darwin was rather bored by Robert Jameson's natural-history course, which covered geology - including the debate between Neptunism and Plutonism. He learned the classification of plants, and assisted with work on the collections of the University Museum, one of the largest museums in Europe at the time.

Darwin's neglect of medical studies annoyed his father, who shrewdly sent him to Christ's College, Cambridge, to study for a Bachelor of Arts degree as the first step towards becoming an Anglican parson. As Darwin was unqualified for the Tripos, he joined the ordinary degree course in January 1828. He preferred riding and shooting to studying. His cousin William Darwin Fox introduced him to the popular craze for beetle collecting; Darwin pursued this zealously, getting some of his finds published in Stevens' Illustrations of British entomology. He became a close friend and follower of botany professor John Stevens Henslow and met other leading parson-naturalists who saw scientific work as religious natural theology, becoming known to these dons as "the man who walks with Henslow". When his own exams drew near, Darwin focused on his studies and was delighted by the language and logic of William Paley's Evidences of Christianity (1794). In his final examination in January 1831 Darwin did well, coming tenth out of 178 candidates for the ordinary degree.

Darwin had to stay at Cambridge until June 1831. He studied Paley's Natural Theology or Evidences of the Existence and Attributes of the Deity (first published in 1802), which made an argument for divine design in nature, explaining adaptation as God acting through laws of nature.[30] He read John Herschel's new book, Preliminary Discourse on the Study of Natural Philosophy (1831), which described the highest aim of natural philosophy as understanding such laws through inductive reasoning based on observation, and Alexander von Humboldt's Personal Narrative of scientific travels in 1799-1804. Inspired with "a burning zeal" to contribute, Darwin planned to visit Tenerife with some classmates after graduation to study natural history in the tropics. In preparation, he joined Adam Sedgwick's geology course, then travelled with him in the summer for a fortnight, in order to map strata in Wales.

Voyage of the Beagle

For more details on this topic, see Second voyage of HMS Beagle.

Route from Plymouth, England, south to Cape Verde then southwest across the Atlantic to Bahia, Brazil, south to Rio de Janeiro, Montevideo, the Falkland Islands, round the tip of South America then north to Valparaiso and Callao. Northwest to the Galapagos Islands before sailing west across the Pacific to New Zealand, Sydney, Hobart in Tasmania, and King George's Sound in Western Australia. Northwest to the Keeling Islands, southwest to Mauritius and Cape Town, then northwest to Bahia and northeast back to Plymouth.

The voyage of the Beagle, 1831–1836

After a week with student friends at Barmouth, Darwin returned home on 29 August to find a letter from Henslow proposing him as a suitable (if unfinished) gentleman naturalist for a self-funded supernumerary place on HMS Beagle with captain Robert FitzRoy, more as a companion than a mere collector. The ship was to leave in four weeks on an expedition to chart the coastline of South America. Robert Darwin objected to his son's planned two-year voyage, regarding it as a waste of time, but was persuaded by his brother-in-law, Josiah Wedgwood, to agree to (and fund) his son's participation. Darwin took care to remain in a private capacity to retain control over his collection: the ship's surgeon Robert McCormick expected to be the official naturalist.

After delays, the voyage began on 27 December 1831; it lasted almost five years. As FitzRoy had intended, Darwin spent most of that time on land investigating geology and making natural history collections, while the Beagle surveyed and charted coasts. He kept careful notes of his observations and theoretical speculations, and at intervals during the voyage his specimens were sent to Cambridge together with letters including a copy of his journal for his family. He had some expertise in geology, beetle collecting and dissecting marine invertebrates, but in all other areas was a novice and ably collected specimens for expert appraisal.Despite suffering badly from seasickness, Darwin wrote copious notes while on board the ship. Most of his zoology notes are about marine invertebrates, starting with plankton collected in a calm spell.

On their first stop ashore at St Jago in Cape Verde, Darwin found that a white band high in the volcanic rock cliffs included seashells. FitzRoy had given him the first volume of Charles Lyell's Principles of Geology, which set out uniformitarian concepts of land slowly rising or falling over immense periods, and Darwin saw things Lyell's way, theorising and thinking of writing a book on geology.

When they reached Brazil, Darwin was delighted by the tropical forest, but detested the sight of slavery. McCormick left the ship at this point, feeling that Darwin had supplanted him as naturalist.

The survey continued to the south in Patagonia. They stopped at Bahía Blanca, and in cliffs near Punta Alta Darwin made a major find of fossil bones of huge extinct mammals beside modern seashells, indicating recent extinction with no signs of change in climate or catastrophe. He identified the little-known Megatherium by a tooth and its association with bony armour, which had at first seemed to him to be like a giant version of the armour on local armadillos. The finds brought great interest when they reached England.

On rides with gauchos into the interior to explore geology and collect more fossils, Darwin gained social, political and anthropological insights into both native and colonial people at a time of revolution, and learnt that two types of rhea had separate but overlapping territories. Further south, he saw stepped plains of shingle and seashells as raised beaches showing a series of elevations. He read Lyell's second volume and accepted its view of "centres of creation" of species, but his discoveries and theorising challenged Lyell's ideas of smooth continuity and of extinction of species.

On a sea inlet surrounded by steep hills, with high snow-covered mountains in the distance, someone standing in an open canoe waves at a square-rigged sailing ship, seen from the front

As HMS Beagle surveyed the coasts of South America, Darwin theorised about geology and extinction of giant mammals.

Three Fuegians on board, who had been seized during the first Beagle voyage and had spent a year in England, were taken back to Tierra del Fuego as missionaries. Darwin found them friendly and civilised, yet their relatives seemed "miserable, degraded savages", as different as wild from domesticated animals. To Darwin, the difference showed cultural advances, not racial inferiority. Unlike his scientist friends, he now thought there was no unbridgeable gap between humans and animals. A year on, the mission had been abandoned. The Fuegian they had named Jemmy Button lived like the other natives, had a wife, and had no wish to return to England.

Darwin experienced an earthquake in Chile and saw signs that the land had just been raised, including mussel-beds stranded above high tide. High in the Andes he saw seashells, and several fossil trees that had grown on a sand beach. He theorised that as the land rose, oceanic islands sank, and coral reefs round them grew to form atolls.

On the geologically new Galápagos Islands, Darwin looked for evidence attaching wildlife to an older "centre of creation", and found mockingbirds allied to those in Chile but differing from island to island. He heard that slight variations in the shape of tortoise shells showed which island they came from, but failed to collect them, even after eating tortoises taken on board as food.[54][55] In Australia, the marsupial rat-kangaroo and the platypus seemed so unusual that Darwin thought it was almost as though two distinct Creators had been at work. He found the Aborigines "good-humoured & pleasant", and noted their depletion by European settlement.

The Beagle investigated how the atolls of the Cocos (Keeling) Islands had formed, and the survey supported Darwin's theorising. FitzRoy began writing the official Narrative of the Beagle voyages, and after reading Darwin's diary he proposed incorporating it into the account. Darwin's Journal was eventually rewritten as a separate third volume, on natural history.

In Cape Town, Darwin and FitzRoy met John Herschel, who had recently written to Lyell praising his uniformitarianism as opening bold speculation on "that mystery of mysteries, the replacement of extinct species by others" as "a natural in contradistinction to a miraculous process". When organising his notes as the ship sailed home, Darwin wrote that, if his growing suspicions about the mockingbirds, the tortoises and the Falkland Islands fox were correct, "such facts undermine the stability of Species", then cautiously added "would" before "undermine". He later wrote that such facts "seemed to me to throw some light on the origin of species".

Inception of Darwin's evolutionary theory

For more details on this topic, see Inception of Darwin's theory.

Three quarter length portrait of Darwin aged about 30, with straight brown hair receding from his high forehead and long side-whiskers, smiling quietly, in wide lapelled jacket, waistcoat and high collar with cravat.

While still a young man, Charles Darwin joined the scientific elite.

When the Beagle reached Falmouth, Cornwall, on 2 October 1836, Darwin was already a celebrity in scientific circles as in December 1835 Henslow had fostered his former pupil's reputation by giving selected naturalists a pamphlet of Darwin's geological letters. Darwin visited his home in Shrewsbury and saw relatives, then hurried to Cambridge to see Henslow, who advised him on finding naturalists available to catalogue the collections and agreed to take on the botanical specimens. Darwin's father organised investments, enabling his son to be a self-funded gentleman scientist, and an excited Darwin went round the London institutions being fêted and seeking experts to describe the collections. Zoologists had a huge backlog of work, and there was a danger of specimens just being left in storage.

Charles Lyell eagerly met Darwin for the first time on 29 October and soon introduced him to the up-and-coming anatomist Richard Owen, who had the facilities of the Royal College of Surgeons to work on the fossil bones collected by Darwin. Owen's surprising results included other gigantic extinct ground sloths as well as the Megatherium, a near complete skeleton of the unknown Scelidotherium and a hippopotamus-sized rodent-like skull named Toxodon resembling a giant capybara. The armour fragments were actually from Glyptodon, a huge armadillo-like creature as Darwin had initially thought. These extinct creatures were related to living species in South America.

In mid-December, Darwin took lodgings in Cambridge to organise work on his collections and rewrite his Journal. He wrote his first paper, showing that the South American landmass was slowly rising, and with Lyell's enthusiastic backing read it to the Geological Society of London on 4 January 1837. On the same day, he presented his mammal and bird specimens to the Zoological Society. The ornithologist John Gould soon announced that the Galapagos birds that Darwin had thought a mixture of blackbirds, "gros-beaks" and finches, were, in fact, twelve separate species of finches. On 17 February, Darwin was elected to the Council of the Geological Society, and Lyell's presidential address presented Owen's findings on Darwin's fossils, stressing geographical continuity of species as supporting his uniformitarian ideas.

Early in March, Darwin moved to London to be near this work, joining Lyell's social circle of scientists and experts such as Charles Babbage, who described God as a programmer of laws. Darwin stayed with his freethinking brother Erasmus, part of this Whig circle and a close friend of the writer Harriet Martineau, who promoted Malthusianism underlying the controversial Whig Poor Law reforms to stop welfare from causing overpopulation and more poverty. As a Unitarian, she welcomed the radical implications of transmutation of species, promoted by Grant and younger surgeons influenced by Geoffroy. Transmutation was anathema to Anglicans defending social order, but reputable scientists openly discussed the subject and there was wide interest in John Herschel's letter praising Lyell's approach as a way to find a natural cause of the origin of new species.

Gould met Darwin and told him that the Galápagos mockingbirds from different islands were separate species, not just varieties, and what Darwin had thought was a "wren" was also in the finch group. Darwin had not labelled the finches by island, but from the notes of others on the Beagle, including FitzRoy, he allocated species to islands. The two rheas were also distinct species, and on 14 March Darwin announced how their distribution changed going southwards.

A page of hand-written notes, with a sketch of branching lines.

In mid-July 1837 Darwin started his "B" notebook on Transmutation of Species, and on page 36 wrote "I think" above his first evolutionary tree.

By mid-March, Darwin was speculating in his Red Notebook on the possibility that "one species does change into another" to explain the geographical distribution of living species such as the rheas, and extinct ones such as the strange Macrauchenia, which resembled a giant guanaco. His thoughts on lifespan, asexual reproduction and sexual reproduction developed in his "B" notebook around mid-July on to variation in offspring "to adapt & alter the race to changing world" explaining the Galápagos tortoises, mockingbirds and rheas. He sketched branching descent, then a genealogical branching of a single evolutionary tree, in which "It is absurd to talk of one animal being higher than another", discarding Lamarck's independent lineages progressing to higher forms.

Overwork, illness, and marriage

See also: Charles Darwin's health

While developing this intensive study of transmutation, Darwin became mired in more work. Still rewriting his Journal, he took on editing and publishing the expert reports on his collections, and with Henslow's help obtained a Treasury grant of £1,000 to sponsor this multi-volume Zoology of the Voyage of H.M.S. Beagle, a sum equivalent to about £81,000 in 2013.He stretched the funding to include his planned books on geology, and agreed unrealistic dates with the publisher. As the Victorian era began, Darwin pressed on with writing his Journal, and in August 1837 began correcting printer's proofs.

Darwin's health suffered under the pressure. On 20 September he had "an uncomfortable palpitation of the heart", so his doctors urged him to "knock off all work" and live in the country for a few weeks. After visiting Shrewsbury he joined his Wedgwood relatives at Maer Hall, Staffordshire, but found them too eager for tales of his travels to give him much rest. His charming, intelligent, and cultured cousin Emma Wedgwood, nine months older than Darwin, was nursing his invalid aunt. His uncle Jos pointed out an area of ground where cinders had disappeared under loam and suggested that this might have been the work of earthworms, inspiring "a new & important theory" on their role in soil formation, which Darwin presented at the Geological Society on 1 November.

William Whewell pushed Darwin to take on the duties of Secretary of the Geological Society. After initially declining the work, he accepted the post in March 1838.Despite the grind of writing and editing the Beagle reports, Darwin made remarkable progress on transmutation, taking every opportunity to question expert naturalists and, unconventionally, people with practical experience such as farmers and pigeon fanciers.Over time, his research drew on information from his relatives and children, the family butler, neighbours, colonists and former shipmates. He included mankind in his speculations from the outset, and on seeing an orangutan in the zoo on 28 March 1838 noted its childlike behaviour.

Three quarter length portrait of woman aged about 30, with dark hair in centre parting straight on top, then falling in curls on each side. She smiles pleasantly and is wearing an open necked blouse with a large shawl pulled over her arms

Darwin chose to marry his cousin, Emma Wedgwood.

The strain took a toll, and by June he was being laid up for days on end with stomach problems, headaches and heart symptoms. For the rest of his life, he was repeatedly incapacitated with episodes of stomach pains, vomiting, severe boils, palpitations, trembling and other symptoms, particularly during times of stress, such as attending meetings or making social visits. The cause of Darwin's illness remained unknown, and attempts at treatment had little success.

On 23 June, he took a break and went "geologising" in Scotland. He visited Glen Roy in glorious weather to see the parallel "roads" cut into the hillsides at three heights. He later published his view that these were marine raised beaches, but then had to accept that they were shorelines of a proglacial lake.

Fully recuperated, he returned to Shrewsbury in July. Used to jotting down daily notes on animal breeding, he scrawled rambling thoughts about career and prospects on two scraps of paper, one with columns headed "Marry" and "Not Marry". Advantages included "constant companion and a friend in old age ... better than a dog anyhow", against points such as "less money for books" and "terrible loss of time." Having decided in favour, he discussed it with his father, then went to visit Emma on 29 July. He did not get around to proposing, but against his father's advice he mentioned his ideas on transmutation.

Malthus and natural selection

Continuing his research in London, Darwin's wide reading now included the sixth edition of Malthus's An Essay on the Principle of Population, and on 28 September 1838 he noted its assertion that human "population, when unchecked, goes on doubling itself every twenty five years, or increases in a geometrical ratio", a geometric progression so that population soon exceeds food supply in what is known as a Malthusian catastrophe. Darwin was well prepared to compare this to de Candolle's "warring of the species" of plants and the struggle for existence among wildlife, explaining how numbers of a species kept roughly stable. As species always breed beyond available resources, favourable variations would make organisms better at surviving and passing the variations on to their offspring, while unfavourable variations would be lost. He wrote that the "final cause of all this wedging, must be to sort out proper structure, & adapt it to changes", so that "One may say there is a force like a hundred thousand wedges trying force into every kind of adapted structure into the gaps of in the economy of nature, or rather forming gaps by thrusting out weaker ones."This would result in the formation of new species.As he later wrote in his Autobiography:

In October 1838, that is, fifteen months after I had begun my systematic enquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here, then, I had at last got a theory by which to work..."

By mid December, Darwin saw a similarity between farmers picking the best stock in selective breeding, and a Malthusian Nature selecting from chance variants so that "every part of newly acquired structure is fully practical and perfected", thinking this comparison "a beautiful part of my theory". He later called his theory natural selection, an analogy with what he termed the artificial selection of selective breeding.

On 11 November, he returned to Maer and proposed to Emma, once more telling her his ideas. She accepted, then in exchanges of loving letters she showed how she valued his openness in sharing their differences, also expressing her strong Unitarian beliefs and concerns that his honest doubts might separate them in the afterlife. While he was house-hunting in London, bouts of illness continued and Emma wrote urging him to get some rest, almost prophetically remarking "So don't be ill any more my dear Charley till I can be with you to nurse you." He found what they called "Macaw Cottage" (because of its gaudy interiors) in Gower Street, then moved his "museum" in over Christmas. On 24 January 1839, Darwin was elected a Fellow of the Royal Society (FRS) in 1839.

On 29 January, Darwin and Emma Wedgwood were married at Maer in an Anglican ceremony arranged to suit the Unitarians, then immediately caught the train to London and their new home.

Geology books, barnacles, evolutionary research

For more details on this topic, see Development of Darwin's theory.

Darwin in his thirties, with his son dressed in a frock sitting on his knee.

Darwin in 1842 with his eldest son, William Erasmus Darwin

Darwin now had the framework of his theory of natural selection "by which to work", as his "prime hobby". His research included extensive experimental selective breeding of plants and animals, finding evidence that species were not fixed and investigating many detailed ideas to refine and substantiate his theory. For fifteen years this work was in the background to his main occupation of writing on geology and publishing expert reports on the Beagle collections.

When FitzRoy's Narrative was published in May 1839, Darwin's Journal and Remarks was such a success as the third volume that later that year it was published on its own. Early in 1842, Darwin wrote about his ideas to Charles Lyell, who noted that his ally "denies seeing a beginning to each crop of species".

Darwin's book The Structure and Distribution of Coral Reefs on his theory of atoll formation was published in May 1842 after more than three years of work, and he then wrote his first "pencil sketch" of his theory of natural selection.To escape the pressures of London, the family moved to rural Down House in September. On 11 January 1844, Darwin mentioned his theorising to the botanist Joseph Dalton Hooker, writing with melodramatic humour "it is like confessing a murder". Hooker replied "There may in my opinion have been a series of productions on different spots, & also a gradual change of species. I shall be delighted to hear how you think that this change may have taken place, as no presently conceived opinions satisfy me on the subject."

Path covered in sandy gravel winding through open woodland, with plants and shrubs growing on each side of the path.

Darwin's "sandwalk" at Down House was his usual "Thinking Path".

By July, Darwin had expanded his "sketch" into a 230-page "Essay", to be expanded with his research results if he died prematurely. In November, the anonymously published sensational best-seller Vestiges of the Natural History of Creation brought wide interest in transmutation. Darwin scorned its amateurish geology and zoology, but carefully reviewed his own arguments. Controversy erupted, and it continued to sell well despite contemptuous dismissal by scientists.

Darwin completed his third geological book in 1846. He now renewed a fascination and expertise in marine invertebrates, dating back to his student days with Grant, by dissecting and classifying the barnacles he had collected on the voyage, enjoying observing beautiful structures and thinking about comparisons with allied structures. In 1847, Hooker read the "Essay" and sent notes that provided Darwin with the calm critical feedback that he needed, but would not commit himself and questioned Darwin's opposition to continuing acts of creation.

In an attempt to improve his chronic ill health, Darwin went in 1849 to Dr. James Gully's Malvern spa and was surprised to find some benefit from hydrotherapy. Then, in 1851, his treasured daughter Annie fell ill, reawakening his fears that his illness might be hereditary, and after a long series of crises she died.

In eight years of work on barnacles (Cirripedia), Darwin's theory helped him to find "homologies" showing that slightly changed body parts served different functions to meet new conditions, and in some genera he found minute males parasitic on hermaphrodites, showing an intermediate stage in evolution of distinct sexes. In 1853, it earned him the Royal Society's Royal Medal, and it made his reputation as a biologist. In 1854 he became a Fellow of the Linnean Society of London, gaining postal access to its library. He began a major reassessment of his theory of species, and in November realised that divergence in the character of descendants could be explained by them becoming adapted to "diversified places in the economy of nature".

Publication of the theory of natural selection

For more details on this topic, see Publication of Darwin's theory.

Studio photo showing Darwin's characteristic large forehead and bushy eyebrows with deep set eyes, pug nose and mouth set in a determined look. He is bald on top, with dark hair and long side whiskers but no beard or moustache.

Charles Darwin, aged 46 in 1855, by then working towards publication of his theory of natural selection. He wrote to Hooker about this portrait, "if I really have as bad an expression, as my photograph gives me, how I can have one single friend is surprising."

By the start of 1856, Darwin was investigating whether eggs and seeds could survive travel across seawater to spread species across oceans. Hooker increasingly doubted the traditional view that species were fixed, but their young friend Thomas Henry Huxley was firmly against the transmutation of species. Lyell was intrigued by Darwin's speculations without realising their extent. When he read a paper by Alfred Russel Wallace, "On the Law which has Regulated the Introduction of New Species", he saw similarities with Darwin's thoughts and urged him to publish to establish precedence. Though Darwin saw no threat, he began work on a short paper. Finding answers to difficult questions held him up repeatedly, and he expanded his plans to a "big book on species" titled Natural Selection. He continued his researches, obtaining information and specimens from naturalists worldwide including Wallace who was working in Borneo. The American botanist Asa Gray showed similar interests and, on 5 September 1857, Darwin sent Gray a detailed outline of his ideas including an abstract of Natural Selection. In December, Darwin received a letter from Wallace asking if the book would examine human origins. He responded that he would avoid that subject, "so surrounded with prejudices", while encouraging Wallace's theorising and adding that "I go much further than you."

Darwin's book was only partly written when, on 18 June 1858, he received a paper from Wallace describing natural selection. Shocked that he had been "forestalled", Darwin sent it on that day to Lyell, as requested by Wallace, and although Wallace had not asked for publication, Darwin suggested he would send it to any journal that Wallace chose. His family was in crisis with children in the village dying of scarlet fever, and he put matters in the hands of his friends. After some discussion, Lyell and Hooker decided on a joint presentation at the Linnean Society on 1 July of On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection. On the evening of 28 June, Darwin's baby son died of scarlet fever after almost a week of severe illness, and he was too distraught to attend.

There was little immediate attention to this announcement of the theory; the president of the Linnean Society remarked in May 1859 that the year had not been marked by any revolutionary discoveries. Only one review rankled enough for Darwin to recall it later; Professor Samuel Haughton of Dublin claimed that "all that was new in them was false, and what was true was old". Darwin struggled for thirteen months to produce an abstract of his "big book", suffering from ill health but getting constant encouragement from his scientific friends. Lyell arranged to have it published by John Murray.

On the Origin of Species proved unexpectedly popular, with the entire stock of 1,250 copies oversubscribed when it went on sale to booksellers on 22 November 1859. In the book, Darwin set out "one long argument" of detailed observations, inferences and consideration of anticipated objections. His only allusion to human evolution was the understatement that "light will be thrown on the origin of man and his history". His theory is simply stated in the introduction:

As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.

He put a strong case for common descent, and at the end of the book concluded that:

There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

The last word was the only variant of "evolved" in the first five editions of the book. "Evolutionism" at that time was associated with other concepts, most commonly with embryological development, and Darwin first used the word evolution in The Descent of Man in 1871, before adding it in 1872 to the 6th edition of The Origin of Species.

Responses to publication

Three quarter length portrait of sixty-year-old man, balding, with white hair and long white bushy beard, with heavy eyebrows shading his eyes looking thoughtfully into the distance, wearing a wide lapelled jacket.

During the Darwin family's 1868 holiday in her Isle of Wight cottage, Julia Margaret Cameron took portraits showing the bushy beard Darwin grew between 1862 and 1866.

White bearded head of Darwin with the body of a crouching ape.

An 1871 caricature following publication of The Descent of Man was typical of many showing Darwin with an ape body, identifying him in popular culture as the leading author of evolutionary theory.

For more details on this topic, see Reaction to On the Origin of Species.

The book aroused international interest, with less controversy than had greeted the popular Vestiges of the Natural History of Creation. Though Darwin's illness kept him away from the public debates, he eagerly scrutinised the scientific response, commenting on press cuttings, reviews, articles, satires and caricatures, and corresponded on it with colleagues worldwide. Darwin had only said "Light will be thrown on the origin of man", but the first review claimed it made a creed of the "men from monkeys" idea from Vestiges. Amongst early favourable responses, Huxley's reviews swiped at Richard Owen, leader of the scientific establishment Huxley was trying to overthrow. In April, Owen's review attacked Darwin's friends and condescendingly dismissed his ideas, angering Darwin, but Owen and others began to promote ideas of supernaturally guided evolution. Patrick Matthew drew attention to his 1831 book which had a brief appendix suggesting a concept of natural selection leading to new species, but he had not developed the idea.

The Church of England's response was mixed. Darwin's old Cambridge tutors Sedgwick and Henslow dismissed the ideas, but liberal clergymen interpreted natural selection as an instrument of God's design, with the cleric Charles Kingsley seeing it as "just as noble a conception of Deity". In 1860, the publication of Essays and Reviews by seven liberal Anglican theologians diverted clerical attention from Darwin, with its ideas including higher criticism attacked by church authorities as heresy. In it, Baden Powell argued that miracles broke God's laws, so belief in them was atheistic, and praised "Mr Darwin's masterly volume [supporting] the grand principle of the self-evolving powers of nature". Asa Gray discussed teleology with Darwin, who imported and distributed Gray's pamphlet on theistic evolution, Natural Selection is not inconsistent with natural theology. The most famous confrontation was at the public 1860 Oxford evolution debate during a meeting of the British Association for the Advancement of Science, where the Bishop of Oxford Samuel Wilberforce, though not opposed to transmutation of species, argued against Darwin's explanation and human descent from apes. Joseph Hooker argued strongly for Darwin, and Thomas Huxley's legendary retort, that he would rather be descended from an ape than a man who misused his gifts, came to symbolise a triumph of science over religion.

Even Darwin's close friends Gray, Hooker, Huxley and Lyell still expressed various reservations but gave strong support, as did many others, particularly younger naturalists. Gray and Lyell sought reconciliation with faith, while Huxley portrayed a polarisation between religion and science. He campaigned pugnaciously against the authority of the clergy in education, aiming to overturn the dominance of clergymen and aristocratic amateurs under Owen in favour of a new generation of professional scientists. Owen's claim that brain anatomy proved humans to be a separate biological order from apes was shown to be false by Huxley in a long running dispute parodied by Kingsley as the "Great Hippocampus Question", and discredited Owen.

Darwinism became a movement covering a wide range of evolutionary ideas. In 1863 Lyell's Geological Evidences of the Antiquity of Man popularised prehistory, though his caution on evolution disappointed Darwin. Weeks later Huxley's Evidence as to Man's Place in Nature showed that anatomically, humans are apes, then The Naturalist on the River Amazons by Henry Walter Bates provided empirical evidence of natural selection. Lobbying brought Darwin Britain's highest scientific honour, the Royal Society's Copley Medal, awarded on 3 November 1864. That day, Huxley held the first meeting of what became the influential X Club devoted to "science, pure and free, untrammelled by religious dogmas". By the end of the decade most scientists agreed that evolution occurred, but only a minority supported Darwin's view that the chief mechanism was natural selection.

The Origin of Species was translated into many languages, becoming a staple scientific text attracting thoughtful attention from all walks of life, including the "working men" who flocked to Huxley's lectures. Darwin's theory also resonated with various movements at the time and became a key fixture of popular culture. Cartoonists parodied animal ancestry in an old tradition of showing humans with animal traits, and in Britain these droll images served to popularise Darwin's theory in an unthreatening way. While ill in 1862 Darwin began growing a beard, and when he reappeared in public in 1866 caricatures of him as an ape helped to identify all forms of evolutionism with Darwinism.

Descent of Man, sexual selection, and botany

Head and shoulders portrait, increasingly bald with rather uneven bushy white eyebrows and beard, his wrinkled forehead suggesting a puzzled frown

By 1878, an increasingly famous Darwin had suffered years of illness.

Letter from Charles Darwin to John Burdon-Sanderson

See also: Darwin from Orchids to Variation, Darwin from Descent of Man to Emotions and Darwin from Insectivorous Plants to Worms

Despite repeated bouts of illness during the last twenty-two years of his life, Darwin's work continued. Having published On the Origin of Species as an abstract of his theory, he pressed on with experiments, research, and writing of his "big book". He covered human descent from earlier animals including evolution of society and of mental abilities, as well as explaining decorative beauty in wildlife and diversifying into innovative plant studies.

Enquiries about insect pollination led in 1861 to novel studies of wild orchids, showing adaptation of their flowers to attract specific moths to each species and ensure cross fertilisation. In 1862 Fertilisation of Orchids gave his first detailed demonstration of the power of natural selection to explain complex ecological relationships, making testable predictions. As his health declined, he lay on his sickbed in a room filled with inventive experiments to trace the movements of climbing plants. Admiring visitors included Ernst Haeckel, a zealous proponent of Darwinismus incorporating Lamarckism and Goethe's idealism. Wallace remained supportive, though he increasingly turned to Spiritualism.

The Variation of Animals and Plants under Domestication of 1868 was the first part of Darwin's planned "big book", and included his unsuccessful hypothesis of pangenesis attempting to explain heredity. It sold briskly at first, despite its size, and was translated into many languages. He wrote most of a second part, on natural selection, but it remained unpublished in his lifetime.

Darwin's figure is shown seated, dressed in a toga, in a circular frame labelled "TIME'S METER" around which a succession of figures spiral, starting with an earthworm emerging from the broken letters "CHAOS" then worms with head and limbs, followed by monkeys, apes, primitive men, a loin cloth clad hunter with a club, and a gentleman who tips his top hat to Darwin.

Punch's almanac for 1882, published shortly before Darwin's death, depicts him amidst evolution from chaos to Victorian gentleman with the title Man Is But A Worm.

Lyell had already popularised human prehistory, and Huxley had shown that anatomically humans are apes. With The Descent of Man, and Selection in Relation to Sex published in 1871, Darwin set out evidence from numerous sources that humans are animals, showing continuity of physical and mental attributes, and presented sexual selection to explain impractical animal features such as the peacock's plumage as well as human evolution of culture, differences between sexes, and physical and cultural racial characteristics, while emphasising that humans are all one species. His research using images was expanded in his 1872 book The Expression of the Emotions in Man and Animals, one of the first books to feature printed photographs, which discussed the evolution of human psychology and its continuity with the behaviour of animals. Both books proved very popular, and Darwin was impressed by the general assent with which his views had been received, remarking that "everybody is talking about it without being shocked." His conclusion was "that man with all his noble qualities, with sympathy which feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system–with all these exalted powers–Man still bears in his bodily frame the indelible stamp of his lowly origin."

His evolution-related experiments and investigations led to books on Insectivorous Plants, The Effects of Cross and Self Fertilisation in the Vegetable Kingdom, different forms of flowers on plants of the same species, and The Power of Movement in Plants. In his last book he returned to The Formation of Vegetable Mould through the Action of Worms.

Death and funeral

See also: Darwin from Insectivorous Plants to Worms

Tombs of John Herschel and Charles Darwin. Westminster Abbey.

In 1882 he was diagnosed with what was called "angina pectoris" which then meant coronary thrombosis and disease of the heart. At the time of his death, the physicians diagnosed "anginal attacks", and "heart-failure".

He died at Down House on 19 April 1882. His last words were to his family, telling Emma "I am not the least afraid of death – Remember what a good wife you have been to me – Tell all my children to remember how good they have been to me", then while she rested, he repeatedly told Henrietta and Francis "It's almost worth while to be sick to be nursed by you". He had expected to be buried in St Mary's churchyard at Downe, but at the request of Darwin's colleagues, after public and parliamentary petitioning, William Spottiswoode (President of the Royal Society) arranged for Darwin to be buried in Westminster Abbey, close to John Herschel and Isaac Newton. The funeral was held on Wednesday 26 April and was attended by thousands of people, including family, friends, scientists, philosophers and dignitaries.

Legacy

Three-quarter portrait of a senior Darwin dressed in black before a black background. His face and six-inch white beard are dramatically lit from the side. His eyes are shaded by his brows and look directly and thoughtfully at the viewer.

In 1881 Darwin was an eminent figure, still working on his contributions to evolutionary thought that had an enormous effect on many fields of science. Portrait by John Collier.

Darwin had convinced most scientists that evolution as descent with modification was correct, and he was regarded as a great scientist who had revolutionised ideas. Though few agreed with his view that "natural selection has been the main but not the exclusive means of modification", he was honoured in June 1909 by more than 400 officials and scientists from across the world who met in Cambridge to commemorate his centenary and the fiftieth anniversary of On the Origin of Species. During this period, which has been called "the eclipse of Darwinism", scientists proposed various alternative evolutionary mechanisms which eventually proved untenable. Ronald Fisher, an English statistician finally united Mendelian genetics with natural selection between 1918 and his 1930 book The Genetical Theory of Natural Selection,[158] giving the theory a mathematical footing and bringing broad scientific consensus that it was the basic mechanism of evolution, founding the basis for population genetics and the modern evolutionary synthesis, with J.B.S. Haldane and Sewall Wright, which set the frame of reference for modern debates and refinements of the theory.

Commemoration

Main article: Commemoration of Charles Darwin

See also: List of things named after Charles Darwin and List of taxa described by Charles Darwin

During Darwin's lifetime, many geographical features were given his name. An expanse of water adjoining the Beagle Channel was named Darwin Sound by Robert FitzRoy after Darwin's prompt action, along with two or three of the men, saved them from being marooned on a nearby shore when a collapsing glacier caused a large wave that would have swept away their boats, and the nearby Mount Darwin in the Andes was named in celebration of Darwin's 25th birthday. When the Beagle was surveying Australia in 1839, Darwin's friend John Lort Stokes sighted a natural harbour which the ship's captain Wickham named Port Darwin: a nearby settlement was renamed Darwin in 1911, and it became the capital city of Australia's Northern Territory.

• More than 120 species and nine genera have been named after Darwin. In one example, the group of tanagers related to those Darwin found in the Galápagos Islands became popularly known as "Darwin's finches" in 1947, fostering inaccurate legends about their significance to his work.
• Darwin's work has continued to be celebrated by numerous publications and events. The Linnean Society of London has commemorated Darwin's achievements by the award of the Darwin–Wallace Medal since 1908. Darwin Day has become an annual celebration, and in 2009 worldwide events were arranged for the bicentenary of Darwin's birth and the 150th anniversary of the publication of On the Origin of Species.
• Darwin has been commemorated in the UK, with his portrait printed on the reverse of £10 banknotes printed along with a hummingbird and HMS Beagle, issued by the Bank of England.
• A life size seated statue of Darwin can be seen in the main hall of the Natural History Museum in London.
• Unveiling of the Darwin Statue outside the former Shrewsbury School building in 1897
• A seated statue of Darwin, unveiled 1897, stands in front of Shrewsbury Library, the building that used to house Shrewsbury School, which Darwin attended as a boy. Another statue of Darwin as a young man is situated in the grounds of Christ's College, Cambridge.
• Darwin College, a postgraduate college at Cambridge University, is named after the Darwin family.

Children

• Darwin's children: see also Darwin–Wedgwood family
• William Erasmus Darwin (27 December 1839 – 8 September 1914)
• Anne Elizabeth Darwin (2 March 1841 – 23 April 1851)
• Mary Eleanor Darwin (23 September 1842 – 16 October 1842)
• Henrietta Emma "Etty" Darwin (25 September 1843 – 17 December 1927)
• George Howard Darwin (9 July 1845 – 7 December 1912)
• Elizabeth "Bessy" Darwin (8 July 1847 – 8 June 1926)
• Francis Darwin (16 August 1848 – 19 September 1925)
• Leonard Darwin (15 January 1850 – 26 March 1943)
• Horace Darwin (13 May 1851 – 29 September 1928)
• Charles Waring Darwin (6 December 1856 – 28 June 1858)

The Darwins had ten children: two died in infancy, and Annie's death at the age of ten had a devastating effect on her parents. Charles was a devoted father and uncommonly attentive to his children. Whenever they fell ill, he feared that they might have inherited weaknesses from inbreeding due to the close family ties he shared with his wife and cousin, Emma Wedgwood. He examined this topic in his writings, contrasting it with the advantages of crossing amongst many organisms.Despite his fears, most of the surviving children and many of their descendants went on to have distinguished careers (see Darwin-Wedgwood family).

Of his surviving children, George, Francis and Horace became Fellows of the Royal Society,distinguished as astronomer, botanist and civil engineer, respectively. All three were knighted. Another son, Leonard, went on to be a soldier, politician, economist, eugenicist and mentor of the statistician and evolutionary biologist Ronald Fisher.

Views and opinions

Religious views

For more details on this topic, see Religious views of Charles Darwin.

Three quarter length studio photo of seated girl about nine years old, looking slightly plump and rather solemn, in a striped dress, holding a basket of flowers on her lap.

In 1851 Darwin was devastated when his daughter Annie died. By then his faith in Christianity had dwindled, and he had stopped going to church.

Darwin's family tradition was nonconformist Unitarianism, while his father and grandfather were freethinkers, and his baptism and boarding school were Church of England. When going to Cambridge to become an Anglican clergyman, he did not doubt the literal truth of the Bible. He learned John Herschel's science which, like William Paley's natural theology, sought explanations in laws of nature rather than miracles and saw adaptation of species as evidence of design.On board the Beagle, Darwin was quite orthodox and would quote the Bible as an authority on morality. He looked for "centres of creation" to explain distribution, and related the antlion found near kangaroos to distinct "periods of Creation".

By his return, he was critical of the Bible as history, and wondered why all religions should not be equally valid. In the next few years, while intensively speculating on geology and the transmutation of species, he gave much thought to religion and openly discussed this with his wife Emma, whose beliefs also came from intensive study and questioning. The theodicy of Paley and Thomas Malthus vindicated evils such as starvation as a result of a benevolent creator's laws, which had an overall good effect. To Darwin, natural selection produced the good of adaptation but removed the need for design, and he could not see the work of an omnipotent deity in all the pain and suffering, such as the ichneumon wasp paralysing caterpillars as live food for its eggs. He still viewed organisms as perfectly adapted, and On the Origin of Species reflects theological views. Though he thought of religion as a tribal survival strategy, Darwin was reluctant to give up the idea of God as an ultimate lawgiver. He was increasingly troubled by the problem of evil.

Darwin remained close friends with the vicar of Downe, John Brodie Innes, and continued to play a leading part in the parish work of the church, but from around 1849 would go for a walk on Sundays while his family attended church. He considered it "absurd to doubt that a man might be an ardent theist and an evolutionist" and, though reticent about his religious views, in 1879 he wrote that "I have never been an atheist in the sense of denying the existence of a God. – I think that generally ... an agnostic would be the most correct description of my state of mind".

The "Lady Hope Story", published in 1915, claimed that Darwin had reverted to Christianity on his sickbed. The claims were repudiated by Darwin's children and have been dismissed as false by historians.

Human society

Darwin's views on social and political issues reflected his time and social position. He thought men's eminence over women was the outcome of sexual selection, a view disputed by Antoinette Brown Blackwell in The Sexes Throughout Nature. He valued European civilisation and saw colonisation as spreading its benefits, with the sad but inevitable effect of extermination of savage peoples who did not become civilised. Darwin's theories presented this as natural, and were cited to promote policies that went against his humanitarian principles. Darwin was strongly against slavery, against "ranking the so-called races of man as distinct species", and against ill-treatment of native people.

Darwin was intrigued by his half-cousin Francis Galton's argument, introduced in 1865, that statistical analysis of heredity showed that moral and mental human traits could be inherited, and principles of animal breeding could apply to humans. In The Descent of Man, Darwin noted that aiding the weak to survive and have families could lose the benefits of natural selection, but cautioned that withholding such aid would endanger the instinct of sympathy, "the noblest part of our nature", and factors such as education could be more important. When Galton suggested that publishing research could encourage intermarriage within a "caste" of "those who are naturally gifted", Darwin foresaw practical difficulties, and thought it "the sole feasible, yet I fear utopian, plan of procedure in improving the human race", preferring to simply publicise the importance of inheritance and leave decisions to individuals. Francis Galton named this field of study "eugenics" in 1883.

Darwin and Women

Charles Darwin had a developing view of women throughout his texts and lifetime. The racism of evolution theory has been documented well and widely publicized, but it is known less widely that many evolutionists, including Charles Darwin, also taught that women are biologically inferior to men. Darwin's ideas, including his view of women, have had a major impact on science and society. Many anthropologists contemporary to Darwin concluded that "women's brains were analogous to those of animals," which had "overdeveloped" sense organs "to the detriment of the brain.”[186] While Darwin claimed that women were inferior to men in mind and body, scientists have attempted to disprove this with genetics stating that the traits a man or a woman possesses will carry on to their offspring no matter the gender. Darwin recognized this in his writings; however, he still made the assertion that inherited characteristics are “transmitted more fully to the male than to the female offspring,” despite this being proved incorrect by modern research.

In a telling indication of his attitude about women (just before he married his cousin, Emma Wedgwood), Darwin listed the advantages of marrying, which included: ". . . constant companion, who will feel interested in one, object to be beloved and played with—better than a dog anyhow—Home, and someone to take care of house . . ." (Darwin: 232). The central belief behind Darwin’s views on women were based on his view of natural selection. Darwin believed that the difference between males and females were partly due to “sexual selection.” Darwin’s theory of sexual selection, which can be found in his book The Descent of Man, and Selection in Relation to Sex, states that women, and some men, will choose to mate with someone that is most suitable to them both in talents and in looks; however, it varies depending on the individual’s culture. This proposition of sexual selection readily tied into his other hypothesis of natural selection in the way that evolution will have different outcomes depending on the traits of the suitor the female chooses to reproduce with. This also supports his principle of “survival of the fittest” in the human species.Darwin believed that men were more fit because they hunted and went to war. The weaker men died in battle and the stronger men came back where they then competed with each other for women with whom they then reproduced. He believed that because men had to prove themselves, both intellectually and physically by competing with other men, whereas women only had to prove themselves in the area of looks then all the weak men did not get to reproduce and weak women did. Therefore, the genes passed on from men to future generations were successful or “champion” genes compared to women.

In summary, Darwin concludes that men attain “a higher eminence, in whatever he takes up, than can women—whether requiring deep thought, reason, or imagination, or merely the use of the senses and hands.” If two lists were made of the most eminent men and women in poetry, painting, sculpture, music (inclusive of both composition and performance), history, science, and philosophy, with half-a-dozen names under each subject, the two lists would not bear comparison. We may also infer, from the law of the deviation from averages, so well illustrated by Mr. Galton, in his work on "Hereditary Genius" that . . . the average of mental power in man must be above that of women.

Darwin and Marriage

In one of Darwin’s journal entries dated July 1838 that he titles “This is the Question,” he compares the pros of marriage on the left side of the page and cons of not marrying on the right side of the page. It reads as such:

Darwin reasoned that as a married man he would be a "poor slave, . . . worse than a Negro" but then reminisces that, "one cannot live the solitary life, with groggy old age, friendless  and childless staring in one's face ." Darwin concludes his discussion on the philosophical note saying, "there is many a happy slave" and shortly thereafter, married his cousin, Emma Wedgwood, in January of 1839.1 While Emma had Christian beliefs that conflicted with some of Darwin’s studies, the couple had a successful marriage and went on to raise seven children together.

Evolutionary social movements

Full length portrait of a very thin white bearded Darwin, seated but leaning eagerly forward and smiling.

Caricature from 1871 Vanity Fair

Further information: Darwinism, Eugenics and Social Darwinism

Darwin's fame and popularity led to his name being associated with ideas and movements that, at times, had only an indirect relation to his writings, and sometimes went directly against his express comments.

Thomas Malthus had argued that population growth beyond resources was ordained by God to get humans to work productively and show restraint in getting families, this was used in the 1830s to justify workhouses and laissez-faire economics. Evolution was by then seen as having social implications, and Herbert Spencer's 1851 book Social Statics based ideas of human freedom and individual liberties on his Lamarckian evolutionary theory.

Soon after the Origin was published in 1859, critics derided his description of a struggle for existence as a Malthusian justification for the English industrial capitalism of the time. The term Darwinism was used for the evolutionary ideas of others, including Spencer's "survival of the fittest" as free-market progress, and Ernst Haeckel's racist ideas of human development. Writers used natural selection to argue for various, often contradictory, ideologies such as laissez-faire dog-eat dog capitalism, racism, warfare, colonialism and imperialism. However, Darwin's holistic view of nature included "dependence of one being on another"; thus pacifists, socialists, liberal social reformers and anarchists such as Peter Kropotkin stressed the value of co-operation over struggle within a species.Darwin himself insisted that social policy should not simply be guided by concepts of struggle and selection in nature.

After the 1880s, a eugenics movement developed on ideas of biological inheritance, and for scientific justification of their ideas appealed to some concepts of Darwinism. In Britain, most shared Darwin's cautious views on voluntary improvement and sought to encourage those with good traits in "positive eugenics". During the "Eclipse of Darwinism", a scientific foundation for eugenics was provided by Mendelian genetics. Negative eugenics to remove the "feebleminded" were popular in America, Canada and Australia, and eugenics in the United States introduced compulsory sterilization laws, followed by several other countries. Subsequently, Nazi eugenics brought the field into disrepute.

The term "Social Darwinism" was used infrequently from around the 1890s, but became popular as a derogatory term in the 1940s when used by Richard Hofstadter to attack the laissez-faire conservatism of those like William Graham Sumner who opposed reform and socialism. Since then, it has been used as a term of abuse by those opposed to what they think are the moral consequences of evolution.