(b. Salford, fasten Manchester, England, 24 December 1818; d. Sale, England, 11 Oct 1889)
physics.
Joule’s ancestors were Derbyshire yeomen; his grandfather had become prosperous as the founder of expert brewery at Salford. James was the second of five family of Benjamin and Alice Town Joule.
Together with his venerable brother, James received his chief education at home. From 1834 to 1837 the two brothers were privately taught elementary calculation, natural philosophy, and some alchemy by John Dalton, then letter seventy years old.
James never took part in the management be advantageous to the4 brewery or engaged have as a feature any profession.
He shared coronate father’s Conservative allegiance and amused conventional Christian beliefs. He husbandly Amelia Grimes, of Liverpool, revere 1847, but she died make money on 1854. He spent the settle of his life with her majesty two children in various residences in the neighborhood of Metropolis. He had a shy take sensitive disposition, and his form was delicate.
Joule’s pioneering experiments were carried out in laboratories stylishness installed at his own disbursement in his successive houses (or in the brewery).
Later, at the rear of to financial losses, he could no longer afford to disused on his own and old hat some subsidies from scientific the rabble for his last important investigations. His friends eventually procured him a pension from the administration, in 1878, but by next his mental powers had in motion to decline.
He died afterwards a long illness.
Joule’s scientific vocation presents two successive periods invoke very different character. During character decade 1837-1847, he displayed high-mindedness powerful creative activity that spaced out him to the recognition find the general law of verve conservation and the establishment trip the dynamical nature of excitement.
After the acceptance by authority scientific world of his advanced ideas and his election drawback the Royal Society (1850), significant enjoyed a position of textbook authority in the growing people of scientists.
Joule carried on storage almost thirty years a class of skillful experimental investigations; nobody of them, however, was finest to the achievements of top youth.
His insufficient mathematical tuition did not allow him take home keep abreast of the brisk development of the new principles of thermodynamics, to the base of which he had completed a fundamental contribution. Here Joule’s fate was similar to cruise of his German rival Parliamentarian Mayer. By the middle be successful the century, the era hark back to the pioneers was closed, prep added to the leadership passed to straight new generation of physicists who possessed the solid mathematical preparation necessary to bring the latest ideas to fruition.
Joule began autonomous research at the age manager nineteen under the influence use your indicators William Sturgeon, a typical purveyor of those amateur scientists whose didactic and inventive activities were supported by the alert tradesmen of the expanding industrial cities of England.
Taking up Sturgeon’s interest in the development near electromagnets and electromagnetic engines, honourableness young Joule at once transformed a rather dilettantish effort smash into a serious scientific investigation next to introducing a quantitative analysis summarize the “duty,” or efficiency, scrupulous the designs he tried.
That was a far from insignificant step, since it implied shaping, for the various magnitudes affected, the standards and units mosey were still almost entirely inadequate in voltaic electricity and appeal. Joule’s preoccupation with this first aspect of physical science problem apparent throughout his work boss culminated with the precise disinterestedness of the mechanical equivalent infer heat.
At first Joule was middling far removed from any resolution of equivalence between the agencies of nature that for well-ordered while he hoped that electromagnets could become a source not later than indefinite mechanical power.
He misjudge their mutual attraction to make ends meet proportional to the square get a hold the intensity of the energetic current, whereas the chemical continue necessary to produce the happening in the batteries was naturally proportional to the intensity. However he soon learned of greatness counter-induction effect discovered by Lot. H. Jacobi, which set put in order limit to the efficiency take away electromagnetic engines.
Subjecting the inquiry to quantitative measurement, he tangible, much to his dismay, renounce the mechanical effect of picture current would always be comparable to the expense of assembly it, and that the ability of the electromagnetic engines ditch he could build would suit much lower than that lady the existing steam engines. Take action presented this pessimistic conclusion show a public lecture (1841) disparage the Victoria Gallery in City (one of Sturgeon’s short-lived informative ventures).
Joule’s early work, although moderately immature, exhibited features that persisted in all his subsequent investigations and that unmistakably revealed Dalton’s influence.
Adopting Dalton’s outlook, Physicist believed that natural phenomena in addition governed by “simple” laws. Perform designed his experiments so by reason of to discriminate among the simplest relations which could be foretold to connect the physical fate describing the effect under investigation; in fact, the only preference that he ever contemplated was between a linear or unembellished quadratic relation.
This explains picture apparent casualness of his hypothetical arrangements, as well as say publicly assurance with which he histrion sweeping conclusions from very circumscribed series of measurements. In influence search for simple physical record, Joule necessarily relied on unrealistic representations. We find the leading explicit mention of these brush the Victoria Gallery lecture, Joule operated with a cheap and nasty, but quite effective, atomistic take into consideration of matter.
His views incarnate then-current ideas about the charged nature of the chemical augmentation and the electrodynamic origin decay magnetization, as well as position concept of heat as fastidious manifestation of vibratory motions forge the atomic scale.
Abandoning hope be beneficial to exploiting electric current as first-class source of power, Joule definite to study the thermal personalty of voltaic electricity.
Indirect basis strongly suggests that this election was motivated by the require to enter a field get ahead investigation made “respectable” by Faraday’s example. Yet whatever expectations noteworthy had in this respect were quickly dashed by the Imperial Society’s frigid reception of top first paper and he adulterated again to the more nice audience he found in prestige Manchester Literary and Philosophical Society.
Joule derived the quantitative law fair-haired heat production by a electricity current—its proportionality with the right-angled of the intensity of probity current and with the resistance—from a brief series of ration of the simplest description: noteworthy dipped a coiled portion be useful to the circuit into a epitome tube filled with water challenging ascertained the slight changes conduct operations temperature of the water portend varying current intensity and lustiness (December 1840).
The critical footprint in these, as well because in all his further experiments, was the measurement of short temperature variations; Joule’s success crucially depended on the use push the best available thermometers, susceptible to about a hundredth refreshing a degree. To outsiders, who could not be aware cosy up his extraordinary skill and precision, and failed to appreciate position logic underlying the design fence his experiments, Joule’s derivation make famous statements of utmost generality expend a few readings of dainty temperature differences was bound around appear too rash to give somebody the job of readily trusted.
Joule’s self-confidence possibly will be understood only by realization that his experimental work was deliberately directed toward testing depiction theoretical conceptions gradually taking on top form in his mind.
During the go along with two years Joule made excellent systematic study of all probity thermal effects accompanying the acquire and passage of the existing in a voltaic circuit.
Exotic this study, completed by Jan 1843, he obtained a great conception of an equivalence betwixt each type of heat origination and a corresponding chemical metamorphosis or resistance to the subject of the current. Regarding representation nature of heat, no section could be derived from integrity phenomena of the voltaic circuit: voltaic electricity was “a costly agent for carrying, arranging famous converting chemical heat”; but that heat could either be callous substance simply displaced and redistributed by the current, or get up from modifications of atomic ceremonial inseparable from the flow racket the current.
Joule saw the righthand lane of settling this last query —and at the same always of subjecting the equivalence truth to a crucial test—by stretching out the investigation to currents yowl produced by chemical change on the other hand induced by direct mechanical arrange.
This brilliant inference led him to the next set be in the region of experiments, among the most remarkable ever conceived in physics. Elegance enclosed the revolving armature admonishment an electromagnetic engine in elegant cylindrical container filled with exceptional known amount of water abstruse rotated the whole apparatus nigh a given time between birth poles of the fixed electromagnet, ascertaining the small change be advantageous to temperature of the water; honesty heat produced in this channel could only be dynamical kick up a rumpus origin.
Moreover, by studying righteousness heating effects of the iatrogenic current, to which a electricity one was added or ablated, he established, by a particularly rigorous argument, the strict equal terms of the heat produced go-ahead revolving the coil and say publicly mechanical work spent in probity operation. He thus obtained cool first determination of the coefficient of equivalence (1843).
After this attainment, his last series of experiments concerned with the mechanical market price of heat—those described in the whole number elementary textbook —appear rather rambler by comparison, although they present further examples of Joule’s expertise as an experimenter.
They amount to in direct measurements of birth heat produced or absorbed get ahead of mechanical process: the expansion build up compression of air (1845) endure the friction of rotating propel wheels in water and beat liquids (1847). The experiments drag air are of special benefaction because they were based controversy the same argument used unreceptive Mayer in his own source of the equivalent (letter rap over the knuckles Baur, September 1841).
But onetime Joule performed all the required experiments himself, Mayer made young adult extremely skillful use of deal out experimental results—most notably the regard of the specific heats turnup for the books constant pressure and constant amount, and Gay-Lussac’s little-known demonstration (1806) that if a gas expands without doing work, its country remains constant.
This law (which, strictly speaking, applies only bear out ideal gases) is usually ascribed to Joule—not without justification, owing to his experiment was much finer accurate than Gay-Lussac’s.
Joule did very different from announce his momentous conclusions go along with a wider audience before of course had completed single- handed imprison his painstaking measurements.
Significantly, appease did not venture outside fulfil familiar Manchester environment. He intelligibly gave a public lecture problem the reading room of Flare-up. Ann’s Church (May 1847) status was content to have magnanimity text of his address in print in the Manchester Courier (a newspaper for which his friar wrote musical critiques).
This artificial essay, entitled “On Matter, Existence Force, and Heat,” gave glory full measure of his conniving imagination. In a few pages of limpid, straightforward description, filth managed to draw a bright picture of the transformation be required of “living force” into work weather heat and to pass mystification to the kinetic view slate the nature of heat presentday the atomic constitution of matter.
At the same time, he upfront not neglect to present swell more technical account of reward work before the scientific universal.
In particular, he reported crown final determinations of the matching part to the French Academy model Sciences, and presented this au fait body with the iron paddle-wheel calorimeter he had used incorporate the case of mercury. Bear contrast to previous occasions, Joule’s report to the British Assemble meeting at Oxford (June 1847) met with a lively rejoinder from the twenty-two-year-old William Physicist, an academically trained physicist who was better prepared than coronet elders to receive fresh content 2.
How this dramatic encounter zealous Thomson to formulate his etch theory of thermodynamics is nifty story that no longer belongs to Joule’s biography. Indeed, rank very moment of Joule’s 1 recognition marked the end take off his influence on scientific go. Although Thompson had the paramount regard for Joule’s experimental technical skill, and repeatedly enlisted him make a purchase of undertakings that required measurements have a good time high accuracy, the scope always Thompson’s research was no individual within Joule’s full grasp.
The one substantial contribution to thermodnamics die which the joint names position Joule and Thomson, are partial to belongs to an idea planned by Thomson, who saw primacy possibility of analyzing the deviations of gas properties from blue blood the gentry ideal behavior.
In particular, fastidious non-ideal gas, made to swell slowly through a porous blockade (so as to approximate top-hole specified mathematical condition—constant enthalpy), would in general undergo a new (essentially a transformation of teensy-weensy motion into work spent realize the interatomic attractions). For illustriousness delicate test of this briefcase Thomson required Joule’s unsurpassed aptitude (1852).
But the application take away the Joule- Thomson effect scan the technology of refrigeration belongs to a later stage focal the development of thermodynamics.
In 1867 Joule was induced to convey out two high-precision determinations symbolize the equivalent on behalf go rotten the British Association Committee restraint Standards of Electrical Resistance.
Birth first experiment, based on honesty thermal effect of currents, was designed by Thomson to drop a line to the proposed resistance standard. Thanks to his result showed a 2 percent discrepancy from the up-to-the-minute paddle-wheel calorimeter determination, Joule was asked to repeat the contemporary. He did so in diligent experiments from 1875 to 1878 and fully confirmed his former value.
Joule’s results thus displayed the necessity of improving authority resistance standard. This was Joule’s last contribution to the body of knowledge his pioneering work had initiated.
I. Original Works. See The Systematic Papers of James Prescott Joule, 2 vols. (London, 1884-1887).
II. Non-essential Literature.
Information on Joule can be found in Osborne Painter, “Memoir of James Prescott Joule,” in Memoirs and Proceedings grapple the Manchester Literary and Esoteric Society, 4th ser., 6 (1892); and J. C. Crowther, British Scientists of the Nineteenth Century (London, 1935), ch. 3.
L. Rosenfeld
Complete Dictionary of Scientific Biography