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James Prescott Joule

James Joule - Physicist
Born 24 December 1818(1818-12-24)
Salford, Lancashire, England
Died 11 October 1889 (aged 70)
Sale, Cheshire, England
Citizenship British
Fields Physics
Known for First Law of Thermodynamics
Influences John Dalton
John Davies

James Prescott Joule FRS (pronounced /ˈdʒuːl/;[1] 24 December 1818 – 11 October 1889) was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics. The SI derived unit of energy, the joule, is named after him. He worked with Lord Kelvin to develop the absolute scale of temperature, made observations on magnetostriction, and found the relationship between the current through a resistance and the heat dissipated, now called Joule's law.


Early years

1892 illustration of Joule

The son of Benjamin Joule (1784–1858), a wealthy brewer, Joule was tutored at home in Salford until 1834 when he was sent, with his elder brother Benjamin, to study with John Dalton at the Manchester Literary and Philosophical Society. The pair only received two years' education in arithmetic and geometry before Dalton was forced to retire owing to a stroke. However, Dalton's influence made a lasting impression as did that of his associates, chemist William Henry and Manchester engineers Peter Ewart and Eaton Hodgkinson. Joule was subsequently tutored by John Davies. Fascinated by electricity, he and his brother experimented by giving electric shocks to each other and to the family's servants.[2]

Joule became a manager of the brewery and took an active role until the sale of the business in 1854. Science was a hobby but he soon started to investigate the feasibility of replacing the brewery's steam engines with the newly-invented electric motor. In 1838, his first scientific papers on electricity were contributed to Annals of Electricity, the scientific journal founded and operated by Davies's colleague William Sturgeon. He discovered Joule's laws in 1840[3] and hoped to impress the Royal Society but found, not for the last time, that he was perceived as a mere provincial dilettante. When Sturgeon moved to Manchester in 1840, Joule and he became the nucleus of a circle of the city's intellectuals. The pair shared similar sympathies that science and theology could and should be integrated. Joule went on to lecture at Sturgeon's Royal Victoria Gallery of Practical Science.[2]

He went on to realise that burning a pound of coal in a steam engine produced five times as much duty as a pound of zinc consumed in a Grove cell,[4] an early electric battery.[5] Joule's common standard of "economical duty" was the ability to raise one pound by a height of one foot, the foot-pound.[2][6]

Joule was influenced by the thinking of Franz Aepinus and tried to explain the phenomena of electricity and magnetism in terms of atoms surrounded by a "calorific ether in a state of vibration".[2]

However, Joule's interest diverted from the narrow financial question to that of how much work could be extracted from a given source, leading him to speculate about the convertibility of energy. In 1843 he published results of experiments showing that the heating effect he had quantified in 1841 was due to generation of heat in the conductor and not its transfer from another part of the equipment.[7] This was a direct challenge to the caloric theory which held that heat could neither be created nor destroyed. Caloric theory had dominated thinking in the science of heat since it was introduced by Antoine Lavoisier in 1783. Lavoisier's prestige and the practical success of Sadi Carnot's caloric theory of the heat engine since 1824 ensured that the young Joule, working outside either academia or the engineering profession, had a difficult road ahead. Supporters of the caloric theory readily pointed to the symmetry of the Peltier-Seebeck effect to claim that heat and current were convertible, at least approximately, by a reversible process.[2]

The mechanical equivalent of heat

Joule wrote in his 1845 paper:

... the mechanical power exerted in turning a magneto-electric machine is converted into the heat evolved by the passage of the currents of induction through its coils; and, on the other hand, that the motive power of the electro-magnetic engine is obtained at the expense of the heat due to the chemical reactions of the battery by which it is worked.[8]

Joule's Heat Apparatus, 1845

Joule here adopts the language of vis viva (energy), possibly because Hodgkinson had read a review of Ewart's On the measure of moving force to the Literary and Philosophical Society in April 1844.

Further experiments and measurements by Joule led him to estimate the mechanical equivalent of heat as 838 ft·lbf of work to raise the temperature of a pound of water by one degree Fahrenheit.[9] He announced his results at a meeting of the chemical section of the British Association for the Advancement of Science in Cork in 1843 and was met by silence.

Joule was undaunted and started to seek a purely mechanical demonstration of the conversion of work into heat. By forcing water through a perforated cylinder, he was able to measure the slight viscous heating of the fluid. He obtained a mechanical equivalent of 770 ft·lbf/Btu (4.14 J/cal). The fact that the values obtained both by electrical and purely mechanical means were in agreement to at least one order of magnitude was, to Joule, compelling evidence of the reality of the convertibility of work into heat.

Joule now tried a third route. He measured the heat generated against the work done in compressing a gas. He obtained a mechanical equivalent of 823 ft·lbf/Btu (4.43 J/cal).[10] In many ways, this experiment offered the easiest target for Joule's critics but Joule disposed of the anticipated objections by clever experimentation. However, his paper was rejected by the Royal Society and he had to be content with publishing in the Philosophical Magazine. In the paper he was forthright in his rejection of the caloric reasoning of Carnot and Émile Clapeyron, but his theological motivations also became evident:

I conceive that this theory ... is opposed to the recognised principles of philosophy because it leads to the conclusion that vis viva may be destroyed by an improper disposition of the apparatus: Thus Mr Clapeyron draws the inference that 'the temperature of the fire being 1000°C to 2000°C higher than that of the boiler there is an enormous loss of vis viva in the passage of the heat from the furnace to the boiler.' Believing that the power to destroy belongs to the Creator alone I affirm ... that any theory which, when carried out, demands the annihilation of force, is necessarily erroneous.

In 1845, Joule read his paper On the mechanical equivalent of heat to the British Association meeting in Cambridge.[11] In this work, he reported his best-known experiment, involving the use of a falling weight to spin a paddle-wheel in an insulated barrel of water, whose increased temperature he measured. He now estimated a mechanical equivalent of 819 ft·lbf/Btu (4.41 J/cal).

In 1850, Joule published a refined measurement of 772.692 ft·lbf/Btu (4.159 J/cal), closer to twentieth century estimates.[12]

Reception and priority

Joule's apparatus for measuring the mechanical equivalent of heat
For the controversy over priority with Mayer, see Mechanical equivalent of heat: Priority

Much of the initial resistance to Joule's work stemmed from its dependence upon extremely precise measurements. He claimed to be able to measure temperatures to within 1/200 of a degree Fahrenheit. Such precision was certainly uncommon in contemporary experimental physics but his doubters may have neglected his experience in the art of brewing and his access to its practical technologies.[13] He was also ably supported by scientific instrument-maker John Benjamin Dancer.

However, in Germany, Hermann Helmholtz became aware both of Joule's work and the similar 1842 work of Julius Robert von Mayer. Though both men had been neglected since their respective publications, Helmholtz's definitive 1847 declaration of the conservation of energy credited them both.

Also in 1847, another of Joule's presentations at the British Association in Oxford was attended by George Gabriel Stokes, Michael Faraday, and the precocious and maverick William Thomson, later to become Lord Kelvin, who had just been appointed professor of natural philosophy at the University of Glasgow. Stokes was "inclined to be a Joulite" and Faraday was "much struck with it" though he harboured doubts. Thomson was intrigued but skeptical.

Unanticipated, Thomson and Joule met later that year in Chamonix. Joule married Amelia Grimes on 18 August and the couple went on honeymoon. Marital enthusiasm notwithstanding, Joule and Thomson arranged to attempt an experiment a few days later to measure the temperature difference between the top and bottom of the Cascade de Sallanches waterfall, though this subsequently proved impractical.

Though Thomson felt that Joule's results demanded theoretical explanation, he retreated into a spirited defense of the Carnot-Clapeyron school. In his 1848 account of absolute temperature, Thomson wrote that "the conversion of heat (or caloric) into mechanical effect is probably impossible, certainly undiscovered"[14] - but a footnote signaled 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 the 27th, revealing that he was planning his own experiments and hoping for a reconciliation of their two views. 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 his 1851 paper, Thomson was willing to go no further than a compromise 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".

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, and the published results did much to bring about general acceptance of Joule's work and the kinetic theory.

Kinetic theory

James Prescott Joule

Kinetics is the science of motion. Joule was a pupil of Dalton and it is no surprise that he had learned a firm belief in the atomic theory, even though there were many scientists of his time who were still skeptical. He had also been one of the few people receptive to the neglected work of John Herapath on the kinetic theory of gases. He was further profoundly influenced by Peter Ewart's 1813 paper On the measure of moving force.

Joule perceived the relationship between his discoveries and the kinetic theory of heat. His laboratory notebooks reveal that he believed heat to be a form of rotational, rather than translational motion.

Joule could not resist finding antecedents of his views in Francis Bacon, Sir Isaac Newton, John Locke, Benjamin Thompson (Count Rumford) and Sir Humphry Davy. Though such views are justified, Joule went on to estimate a value for the mechanical equivalent of heat of 1034 foot-pound from Rumford's publications. Some modern writers have criticised this approach on the grounds that Rumford's experiments in no way represented systematic quantitative measurements. In one of his personal notes, Joule contends that Mayer's measurement was no more accurate than Rumford's, perhaps in the hope that Mayer had not anticipated his own work.


A statue of Joule in the Manchester Town Hall
Joule's gravestone in Brooklands cemetery, Sale

Joule died at home in Sale[15] and is buried in Brooklands cemetery there. The gravestone is inscribed with the number "772.55", his climacteric 1878 measurement of the mechanical equivalent of heat, and with a quotation from the Gospel of John, "I must work the works of him that sent me, while it is day: the night cometh, when no man can work" (9:4).

Selected writings

  • Joule, J. P. (1963). The Scientific Papers of James Prescott Joule. London: Dawsons of Pall Mall. 


  1. ^ OED: "Although some people of this name call themselves (dʒaʊl), and others (dʒəʊl) [the OED format for /ˈdʒoʊl/], it is almost certain that J. P. Joule (and at least some of his relatives) used (dʒuːl).
  2. ^ a b c d e Smith (2004)
  3. ^ Joule, J.P. (1841) "On the heat evolved by metallic conductors of electricity" Philosophical Magazine, 19, 260; Scientific Papers 65
  4. ^ William Robert Grove was to give one of the earliest general accounts of the conservation of energy in 1844.
  5. ^ Smith (1998) p.60
  6. ^ Joule's unit of the foot-pound corresponds to a modern measure of energy. The energy required to raise a mass, m, through a height h is mgh, where g is the standard gravity. Joule's unit is dimensionally correct if interpreted as foot-pound force. Where SI units are employed, such energy is given in terms of the eponymous joule: 1 foot-pound = 1.356 J.
  7. ^ Joule, James Prescott (1843). "On the calorific effects of magneto-electricity, and on the mechanical value of heat". Philosophical Magazine, Series 3 23: 263–276. 
  8. ^ Joule, James Prescott (1845). "On the Changes of Temperature Produced by the Rarefaction and Condensation of Air". Philosophical Magazine, Series 3 26: 369.,M2. 
  9. ^ Joule's unit corresponds to 5.3803×10-3 J/calorie. Thus Joule's estimate was 4.51 J/cal, compared to the value accepted by the beginning of the 20th century of 4.1860 J/cal (M.W. Zemansky (1968) Heat and Thermodynamics, 5th ed., p. 86).
  10. ^ Joule, J.P. (1845) "On the rarefaction and condensation of air" Philosophical Magazine, Scientific Papers 172
  11. ^ Joule, J.P. (1845) "On the Mechanical Equivalent of Heat", Brit. Assoc. Rep., trans. Chemical Sect, p.31, read before the British Association at Cambridge, June
  12. ^ Joule, J.P (1950) Philosophical Transactions of the Royal Society of London, vol.140, Part 1, pp61-82
  13. ^ Sibum (1994)
  14. ^ See Thomson, William (1848). "On an Absolute Thermometric Scale founded on Carnot's Theory of the Motive Power of Heat, and calculated from Regnault's Observations". Philosophical Journal. - See also the account in Thomson, William (1882). Mathematical and Physical Papers. Cambridge, England: Cambridge University Press. pp. 100–106. 
  15. ^ GRO Register of Deaths: DEC 1889 8a 121 ALTRINCHAM - James Prescott Joule

Further reading

  • Bottomley, J. T. (1882). "James Prescott Joule". Nature 26: 617 – 620. 
  • Cardwell, D. S. L. (1991). James Joule: A Biography. Manchester University Press. ISBN 0-7190-3479-5. 
  • Forrester, J. (1975). "Chemistry and the Conservation of Energy: The Work of James Prescott Joule". Studies in the History and Philosophy of Science 6: 273 – 313. doi:10.1016/0039-3681(75)90025-4. 
  • Fox, R, "James Prescott Joule, 1818–1889", in North, J. (1969). Mid-nineteenth-century scientists. Elsevier. pp. 72–103. ISBN 0-7190-3479-5. 
  • Reynolds, Osbourne (1892). Memoir of James Prescott Joule. Manchester, England: Manchester Literary and Philosophical Society.,M1. Retrieved 2008-03-15. 
  • Sibum, H. O. (1995). "Reworking the mechanical value of heat: instruments of precision and gestures of accuracy in early Victorian England". Studies in History and Philosophy of Science 26: 73 – 106. doi:10.1016/0039-3681(94)00036-9. 
  • Smith, C. (1998). The Science of Energy: A Cultural History of Energy Physics in Victorian Britain. London: Heinemann. ISBN 0-485-11431-3. 
  • — (2004) "Joule, James Prescott (1818–1889)", Oxford Dictionary of National Biography, Oxford University Press, <, accessed 27 July 2005> (subscription required)
  • Smith, C. & Wise, M.N. (1989). Energy and Empire: A Biographical Study of Lord Kelvin. Cambridge University Press. ISBN 0-521-26173-2. 
  • Steffens, H.J. (1979). James Prescott Joule and the Concept of Energy. Watson. ISBN 0-88202-170-2. 

External links



Up to date as of January 14, 2010

From Wikiquote

Joule James sitting.jpg

James Prescott Joule (24 December 181811 October 1889) was an English physicist and brewer. Joule studied the nature of heat, and discovered its relationship to mechanical work.


  • My object has been, first to discover correct principles and then to suggest their practical development.
    • On Electro-magnetic forces (March 10, 1840), in Annals of Electricity, Vol. 4, p. 484.
  • It was in the year 1843 that I read a paper "On the Calorific Effects of Magneto-Electricity and the Mechanical Value of Heat" to the Chemical Section of the British Association assembled at Cork. With the exception of some eminent men, among whom I recollect with pride Dr. Apjohn, the president of the Section, the Earl of Rosse, Mr. Eaton Hodgkinson, and others, the subject did not excite much general attention; so that when I brought it forward again at the meeting in 1847, the chairman suggested that, as the business of the section pressed, I should not read my paper, but confine myself to a short verbal description of my experiments. This I endeavoured to do, and discussion not being invited, the communication would have passed without comment if a young man had not risen in the section, and by his intelligent observations created a lively interest in the new theory. The young man was William Thomson, who had two years previously passed the University of Cambridge with the highest honour, and is now probably the foremost scientific authority of the age.
    • James Prescott Joule (1887). Joint Scientific Papers. The Physical Society of London. p. 215.  

External links

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1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

JAMES PRESCOTT JOULE (1818-1889), English physicist, was born on the 24th of December 1818, at Salford, near Manchester. Although he received some instruction from John Dalkon in chemistry, most of his scientific knowledge was selftaught, and this was especially the case with regard to electricity and electro-magnetism, the subjects in which his earliest researches were carried out. From the first he appreciated the importance of accurate measurement, and all through his life the attainment of exact quantitative data was one of his chief considerations. At the age of nineteen he invented an electromagnetic engine, and in the course of examining its performance dissatisfaction with vague and arbitrary methods of specifying elec rical quantities caused him to adopt a convenient and scie tific unit, which he took to be the amount of electricity req ired to decompose nine grains of water in one hour. In 1840 he ', as thus enabled to give a quantitative statement of the law acc s rding to which heat is produced in a conductor by the pas ageof an electric current, and in succeeding years he publish d a series of valuable researches on the agency of electricity in ansformations of energy. One of these contained the first inti ation of the achievement with which his name is most wid ly associated, for it was in a paper read before the British Association at Cork in 1843, and entitled "The Calorific Effects of i agneto-electricity and the Mechanical Value of Heat," that he xpressed the conviction that whenever mechanical force is exp ° nded an exact equivalent of heat is always obtained. By rot ting a small electro-magnet in water, between the poles of ano her magnet, and then measuring the heat developed in the wat r and other parts of the machine, the current induced in the coils, and the energy required to maintain rotation, he cal b lated that the quantity of heat capable of warming one you d of water one degree F. was equivalent to the mechanical forewhich could raise 838 lb. through the distance of one foot. At he same time he brought forward another determination bas ° d on the heating effects observable when water is forced through capillary tubes; the number obtained in this way was 77 o A third method, depending on the observation of the heat evo ved by the mechanical compression of air, was employed a yea or two later, and yielded the number 798; and a fourth - the wel -known frictional one of stirring water with a sort of paddlewh:el - yielded the result 890 (see Brit. Assoc. Report, 1845), tho gh 781.5 was obtained by subsequent repetitions of the experiment. In 1849 he presented to the Royal Society a memoir which, together with a history of the subject, contained details of a long series of determinations, the result of which was 77 2. A good many years later he was entrusted by the committee of the British Association on standards of electric resist ance with the task of deducing the mechanical equivalent of heat from the thermal effects of electric currents. This inquiry yielded (in 1867) the result 783, and this Joule himself was inclined to regard as more accurate than his old determination by the frictional method; the latter, however, was repeated with every precaution, and again indicated 772.55 foot-pounds as the quantity of work that must be expended at sea-level in the latitude of Greenwich in order to raise the temperature of one pound of water, weighed in vacuo, from 60 to 61° F. Ultimately the discrepancy was traced to an error which, not by Joule's fault, vitiated the determination by the electrical method, for it was found that the standard ohm, as actually defined by the British Association committee and as used by him, was slightly smaller than was intended; when the necessary corrections were made the results of the two methods were almost precisely congruent, and thus the figure 772-55 was vindicated. In addition, numerous other researches stand to Joule's credit - the work done in compressing gases and the thermal changes they undergo when forced under pressure through small apertures (with Lord Kelvin), the change of volume on solution, the change of temperature produced by the longitudinal extension and compression of solids, &c. It was during the experiments involved by the first of these inquiries that Joule was incidentally led to appreciate the value of surface condensation in increasing the efficiency of the steam engine. A new form of condenser was tested on the small engine employed, and the results it yielded formed the starting-point of a series of investigations which were aided by a special grant from the Royal Society, and were described in an elaborate memoir presented to it on the 13th of December 1860. His results, according to Kelvin, led directly and speedily to the present practical method of surface-condensation, one of the most important improvements of the steam engine, especially for marine use, since the days of James Watt. Joule died at Sale on the 11th of October 1889.

His scientific papers were collected and published by the Physical Society of London: the first volume, which appeared in 1884, contained the researches for which he was alone responsible, and the second, dated 1887, those which he carried out in association with other workers.

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Simple English

James Prescott Joule
Born24 December 1818(1818-12-24)
Salford, Lancashire, England
Died11 October 1889 (aged 70)
Sale, Cheshire, England
Known forFirst Law of Thermodynamics

James Prescott Joule (December 24, 1818October 11, 1889) was an English physicist, born in Salford, near Manchester. In his time he had great contribution to the world of electricity and thermodynamics. He was best known for discovering Joule's law, which described electric heating by saying the amount of heat produced each second in a conductor by a current of Electricity is proportional to the resistance of a conductor and to the square of the current. The unit for this is joule, equal to one watt-second. Later Joule worked with William Thomson to find out that the temperature of gas falls, as gas expands. This principle was then know as the Joule-Thomson effect.

Early life

File:James Prescott
1892 illustration of Joule

The son of Benjamin Joule (1784–1858), a wealthy brewer, James Prescott Joule was born in the house next to the Joule Brewery in New Bailey Street, Salford on 24th December 1818.[1] James was tutored at the family home 'Broomhill', Pendlebury, near Salford, until 1834 when he was sent, with his elder brother Benjamin, to study with John Dalton at the Manchester Literary and Philosophical Society.[1] They only received two years of education in arithmetic and geometry before Dalton was forced to retire because of a stroke.

Kinetic theory

File:Joule James Jeens
James Prescott Joule

Kinetics is the science of motion. Joule was a pupil of Dalton and it is no surprise that he had learned a firm belief in the atomic theory, even though there were many scientists of his time who were still skeptical. He had also been one of the few people receptive to the work of John Herapath on the kinetic theory of gases. He was further greatly influenced by Peter Ewart's 1813 paper On the measure of moving force.


  1. 1.0 1.1 Hulme, Charles (2010). "John Cassidy:Manchester Sculptor". John Cassidy 150th Anniversary website. Retrieved 22 March 2010. 
rue:Джеймс Прескотт Джоуль


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