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Reference group
North British network (act. c.1845–c.1890) was an informal group of physicists and engineers, strongly connected with Scotland, that constructed the science of energy in the third quarter of the nineteenth century. Linked by personal friendships, shared scientific interests, and frequent exchanges of correspondence (often addressed from N.B., the abbreviation for North Britain), the network's leading members were William Thomson (later Lord Kelvin), professor of natural philosophy in the University of Glasgow; his brother James Thomson, professor of engineering at Queen's College, Belfast; Macquorn Rankine, regius professor of engineering in the University of Glasgow; James Prescott Joule, experimental philosopher in Manchester; James Clerk Maxwell, professor of natural philosophy in the University of Aberdeen and later professor of experimental physics in the University of Cambridge; Peter Guthrie Tait, professor of natural philosophy in the University of Edinburgh; Fleeming Jenkin, telegraph engineer and later professor of engineering in the University of Edinburgh; and Balfour Stewart, professor of natural philosophy at Owens College, Manchester. The group also had close ties with the German physicist Hermann von Helmholtz. Its members played a leading role in sections A (physics and mathematics) and E (mechanical science and engineering) of the British Association for the Advancement of Science.

The group had its origins in the mid-1840s. While serving a marine engineering apprenticeship at William Fairbairn's iron shipbuilding yard at Millwall, James Thomson communicated his enthusiasm for heat engine economy to his brother William, then a Cambridge undergraduate. The brothers quickly developed a shared interest in Sadi Carnot's theory of the motive power of heat. The theory accounted for the action of heat engines by analogy to water-wheels: just as the fall of water drove a water-wheel, so the fall of heat between high and low temperature drove all types of heat engine. William Thomson's election as a Glasgow professor in 1846 placed him within a North British culture predominantly Presbyterian in religion, strongly unionist and liberal in politics, and increasingly committed to the promotion of heavy industry, especially iron shipbuilding and marine engineering on the Clyde. It was a culture that saw useful work as central: ‘Work itself is salutary, is honourable, is blessed; but painful work, and fruitless work, is a memento of our degradation, a consequence of our fall’, according to one contributor to the magazine Good Words in 1863 (Vaughan, 93).

In the summer of 1847 William Thomson met Joule at the British Association meeting in Oxford. Joule's commitment to the mutual convertibility of work and heat according to an exact numerical equivalence seemed to contradict Carnot's claim that the fall of heat, and not its conversion, generated work. Joule also asserted that no work (or its equivalent) could be really lost in nature: only God could create or destroy the basic building blocks of the universe. Thomson finally reconciled Joule and Carnot in 1850–51. Reintroducing the term ‘energy’ (originally used in mechanics by Thomas Young earlier in the century) as a synonym for such more traditional terms as vis viva (mass times velocity squared), work, and mechanical effect, Thomson now affirmed, like Joule, that God alone could create or destroy energy (the conservation of energy). Following Carnot, he also held that human beings could use and direct transformations of energy from higher to lower states. Failure to direct energy to useful ends resulted in irrecoverable losses of useful work (the dissipation or degradation of energy).

From the early 1850s the Thomson brothers, Joule, and their new Scottish ally in engineering science, Rankine, introduced into traditional mechanics a language of ‘actual’ (‘kinetic’ from 1862) and ‘potential’ energy. In the same period Rankine constructed a ‘science of thermodynamics’ by which engineers could evaluate the imperfections of heat engines. Two other Scottish academics, Maxwell and Tait, soon aligned themselves with the network. With close personal and academic ties to Edinburgh, Maxwell became increasingly involved with the North British network after graduating from Cambridge and taking up a chair of natural philosophy in Aberdeen in 1856. Through his researches in electricity and magnetism he extended the science of energy over the following two decades, culminating in his Treatise on Electricity and Magnetism (1873). Meanwhile Tait became a fresh convert to energy soon after his appointment to the Edinburgh chair of natural philosophy in 1860, and began to prosecute a series of aggressive campaigns on behalf of the North British science of energy and its founders.

The North British network's careful dissemination of energy principles and practices through such well-chosen forums as the British Association aimed to redraw the disciplinary map of physics and to carry forward a reform programme for the whole range of physical and even life sciences. By the early 1860s Thomson and Tait had begun a collaboration to produce a definitive set of treatises on a new natural philosophy structured by the energy principles. Although only the first volume of their Treatise on Natural Philosophy (1867) was published, Maxwell's Treatise followed in similar vein though with characteristics all of its own. Through the 1860s the North Britishers (notably Maxwell, Thomson, Stewart, and Jenkin) spearheaded a British Association campaign to promote the adoption of an absolute system of physical measurement such that all the units (including electrical resistance) should bear a definite relation to the unit of work, now seen as ‘the great connecting link between all physical measurements’ (Smith and Wise, 687). Together with the designing of new electrical measuring instruments, these researches shaped the rapid expansion of telegraphic communication which united the far-flung territories of the British empire in the remaining years of the century. The science of energy, with a claim to universality, had become the basic intellectual property of these élite men of science and engineering.

With its North British audiences centred on Presbyterian Scotland, the network stood in stern opposition to metropolitan groups associated with the doctrines of scientific naturalism. Led by T. H. Huxley and his fellow members of the X Club in London, a rising generation of London-based scientists aspired to a professionalized science founded on the doctrines of evolution by natural selection and conservation of energy, and free from Anglican theological doctrines. Thomson, Tait, and Jenkin all published criticisms of Charles Lyell's uniformitarian geology that allowed seemingly unlimited time for the evolution of species and thus underpinned Charles Darwin's Origin of Species. Based on energy calculations, North British estimates of the age of the earth and sun at less than 100 million years appeared to make evolution by natural selection untenable. Often led by Tait's less than diplomatic pen, North British energy physics found a powerful ally in the Church of Scotland minister Norman Macleod (1812–1872), whose monthly magazine Good Words served to take North British physics to a wide audience.

Tensions within the network, however, were most apparent when Stewart and Tait anonymously published their controversial Unseen Universe, or, Physical Speculations on a Future State (1875). Based on belief in a principle of continuity, the book went too far for the more orthodox Thomson and Maxwell, neither of whom approved of its speculative nature. By the 1880s, however, death rather than internal disagreements had brought about the dissolution of the network. Rankine and Maxwell had already died at the ages of fifty-two and forty-eight. Jenkin, Stewart, and Joule were all gone by 1889. Thomson and Tait alone continued to assert their authority over physical science in Britain into the twentieth century. But against the new generations of scientists they began to look increasingly conservative, survivors from a once-radical era of natural philosophy.

Crosbie Smith


C. Smith, The science of energy: a cultural history of energy physics in Victorian Britain (1998) · C. Smith and M. N. Wise, Energy and empire: a biographical study of Lord Kelvin (1989) · C. J. Vaughan, ‘The divinity of work’, Good Words, 4 (1863), 93–6 · W. Thomson and P. G. Tait, ‘Energy’, Good Words, 3 (1862), 601–7 · P. G. Tait, ‘The dynamical theory of heat’, North British Review, 40 (1864), 40–69 · P. G. Tait, ‘Energy’, North British Review, 40 (1864), 337–68