James Prescott Joule, FRS (1818-1889)

James Prescott Joule

James Prescott Joule, born in Salford, Lancashire on 24 December 1818, was an English physicist and brewer.

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

Joule received the Royal Medal of the Royal Society in 1852, the Copley Medal of the Royal Society in 1870, and the Albert Medal of the Society of Arts from the hand of the Prince of Wales in 1880. In 1860 he became President of Manchester Literary and Philosophical Society. The members list included Robert Owen, John Dalton, James Prescott Joule, Tom Kilburn, Peter Mark Roget, Ernest Rutherford, Joseph Whitworth and many other.

Further information on University of Manchester Archive.

Outstanding contribution to science

Joule's laws

Nature of heat and its relationship to mechanical work
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 formulated Joule's laws in 1840. Joule's Law gave the relationship between the current through resistance and the heat dissipated, now called Joule's law. Joule 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.

Joule studied the nature of heat and discovered its relationship to mechanical work, leading to the theory of conservation of energy and the development of the first law of thermodynamics.

SI units

The SI derived unit of energy, the Joule, is named after him.

Absolute scale of temperature

Joule worked with Lord Kelvin to develop the absolute scale of temperature, and made observations on magnetostriction.

Early Electric battery

Discovered 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, an early electric battery.


Joule's common standard of "economical duty" was the ability to raise one pound by a height of one foot, the foot-pound.

Speed of molecules

Joule also was among the first to attach a number to the speed of molecules, a feat that was lacking in previous theories of the kinetic theory of heat.

All systems contain energy which can be converted from one form to another

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. This was a direct challenge to the caloric theory, which dominated thinking since 1783, and which held that heat could neither be created nor destroyed. 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.


Joule at Manchester 

In Manchester the brothers 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.

Copley Gold Medal

Joule received the Copley Gold Medal of the Royal Society in 1850 for his paper on the Mechanical Equivalent of Heat, printed in the Philosophical Transactions for 1850.

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