James Prescott Joule FRS (pronounced
/'d?u?l/;
[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.
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. Joule was 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, a height of one foot, the foot-pound.[2][6]
