Throughout his career, the historian Bruce Hunt has been one of the key scholars to revivify nineteenth-century physics. Any physicist can name a few giants from that period—just from equations and units, we all know James Clerk Maxwell for his electrodynamics, and Lord Kelvin for introducing an absolute temperature scale. But the routes these giants took often go unexplored.
In textbook physics, technologies provide specific examples of general principles. But from Hunt’s books, one can see how these principles were often codified by individuals whose views differed dramatically from our own, and who often viewed their contemporary technologies as scientific mysteries. Hunt’s first book, The Maxwellians, shows how Maxwell’s disciples altered the form of his theory of electromagnetism so significantly after his death that the Maxwell’s equations taught today were unknown to Maxwell himself.1 In his second book, Pursuing Power and Light: Technology and Physics from James Watt to Albert Einstein, Hunt examines nineteenth-century physics in the glow of nineteenth-century technology.2 He shows that, just as Maxwell—and, later, his disciples—pioneered electromagnetic field theory only after telegraph wires already lined the countryside, the science of thermodynamics was developed only after steam engines were already widespread.
Hunt has now published a third volume, Imperial Science: Cable Telegraphy and Electrical Physics in the Victorian British Empire.3 It marries the electrical history of The Maxwellians to the underlying thesis of Pursuing Power—that science is pushed along by technology just as often as it pulls technology ahead.
Hunt notes that electromagnetic field theory “initially drew adherents only in Britain, and only in the mid-nineteenth century.”4 He frames this development with a question of historical contingency:
But why then, and why there? The answer, as we will see, lies not just in the details of the lives and ideas of a few great men but also in the principal context in which electricity was studied in the middle of the nineteenth century: the telegraph industry, particularly submarine telegraphy.5
Hunt is not unusual in his move away from so-called great men as the principal drivers of scientific history. Historians of science have progressed, more or less, from personal, to cultural, to structural explanations for progress in science. Much of Hunt’s career has been spent studying Victorian physics. His paper “Michael Faraday, Cable Telegraphy, and the Rise of British Field Theory,” which forms the basis for the first chapter of Imperial Science, was published in 1991, the same year as The Maxwellians.6 Yet as he has cast a wider net across Victorian society, the scientists have receded as the main causal drivers of their stories.
Hunt may seem presumptuous in tackling undersea telegraphy. After all, the story of the transatlantic cable is a candidate for the genesis narrative of our modern networked world. As such, many versions of this history already exist, from an academic book showing how early cable titans laid the foundations for modern telecoms;7 to a popular history, nicely illustrated;8 to an educational documentary;9 to a children’s book.10 For scientific readers, Paul Nahin’s Hot Molecules, Cold Electrons: From the Mathematics of Heat to the Development of the Trans-Atlantic Telegraph Cable, published in 2020, explored in some detail—far more detail than Hunt provides—the methods Kelvin used to understand why signals smear out in undersea cables.11
But Hunt has something different in mind. While most histories present this story as a commercial adventure, Hunt explores how the British transatlantic cable saga became pivotal in the history of physics. By juxtaposing the histories of telegraphy and physics in the Victorian British Empire, Hunt is able to show how physics benefited from telegraphy in unexpected ways.
The title for Imperial Science comes from a quotation by Oliver Lodge, a disciple of Maxwell, writing a few decades after field theories had been established. When Lodge’s colleague Heinrich Hertz generated and detected electromagnetic waves in the laboratory, Lodge proclaimed that, “the whole domain of Optics is annexed to Electricity, which has thus become an imperial science.”12 Hunt projects this imperial analogy back to the earlier part of the electrical story, and asserts that undersea telegraphy and field theory were also literal products of the British Empire. When the Brett brothers, John Watkins and Jacob, financed the first cable below the English Channel, it was insulated using gutta-percha, a plastic derived from the latex of Palaquium gutta trees of Malaysia. It was only by virtue of British imperial expansion into Southeast Asia that the entrepreneurs were able to access these resources.
Yet Hunt pursues such connections only halfheartedly. Imperial Science establishes that the production of scientific knowledge was contingent on the British Empire, but not that imperial doctrines have bled into the foundations of field theory. His case rhymes better with Guns, Germs, and Steel than with The Gendered Atom. Hunt’s scientists are surely products of their environments, but this is less a denunciation than a foregone conclusion.
In the early parts of Imperial Science, Hunt only briefly sketches the state of telegraphy before the canonical Victorian physicists got involved. He writes that “the telegraph itself grew out of laboratory discoveries [the Italian] Alessandro Volta and [Danish] Hans Christian Oersted made in the early 1800s.”13 But he does not mention that the first operative electric telegraph was constructed in 1833 by Carl Friedrich Gauss and Wilhelm Eduard Weber in Göttingen, over a short range of a kilometer. Instead he picks up the story four years later in Britain when William Cooke and Charles Wheatstone patented the first commercial telegraph, which was then taken over and developed by the Electric Telegraph Company in 1846. In the United States, Samuel Morse, after hearing of the European projects in telegraphy, had developed a separate system by 1844.
Hunt gives only passing attention to these general developments since, instead, he has a specific interest. Namely, by the 1850s, overland telegraphy was already widespread in the West, but water presented a problem. There was no way to cross it. In the United States, “telegraph messages that had come hundreds of miles at lightning speed had to be taken down in Jersey City and carried to Manhattan by boat.”14 Likewise, telegraph messages zipped across continental Europe, only to halt at the English Channel.
The Bretts’ first telegraph line was laid below the Channel in 1850. It was poorly theorized and failed almost as soon as it was installed. But it served to draw attention to the particular challenges of undersea telegraphy, which soon attracted the attention of notable scientists.
The first half of the nineteenth century was dominated by action-at-a-distance theories of electromagnetic phenomena, pioneered by continental theorists like André-Marie Ampère in France and Weber in Germany. These theories proposed that electrical forces acted instantaneously across space, just as Isaac Newton had proposed for gravitational forces. Given how quickly messages traveled over land by telegraph, such ideas seemed intuitively plausible, despite early hints that this was not the full story.
The first to discover signal retardation was Latimer Clark, of the Electric Telegraph Company, in 1852. When he tested a 100-mile length of insulated wire, meant to extend telegraph networks under the North Sea from London to the Netherlands, he noticed that currents sent through the long wire “were not only slow in appearing, but … tailed off gradually to a point.”15 Clark diagnosed the basic issue: as current traveled down the underwater wire, its electrical forces pulled on the charges in the water, causing the current pulse to slow down and spread out, making the insulated wire into a giant capacitor, with the gutta-percha layer as the insulation separating two conductors—the saltwater and the wire.
Wishing to consult with a specialist, Clark called on Michael Faraday, who was by then already well-known as an electrical researcher. Faraday is now remembered as one of the fathers of field theory, but he was famously illiterate in mathematics—which may explain why he was immune to the elegant formulations of Ampère and Weber. From his direct experimental observations beginning in the 1830s, Faraday came to believe that the electromagnetic field in the space surrounding wires, rather than the currents within them, provided the main stage for electrical phenomena. Undersea cables would soon help him make his case.
Faraday saw Clark’s explanation as bolstering his own claims about electromagnetic fields. Signal retardation—the phenomenon of the electrical signals taking time to propagate down the water-immersed wire—had resulted from the fields around the wires, not just the currents inside.
Hunt credits British geography for bolstering Faraday’s argument. In Prussia, Werner Siemens had noticed the same effect as Clark during a project connecting Berlin and Frankfurt with buried cables, but such troubles were forgotten once the underground cables were replaced by overhead ones. On the British Isles, these issues could not be forgotten. “To put the point simply and a bit too baldly,” Hunt writes, “the British did field theory because they had submarine cables, and the French and Germans did not because they had none.”16
For readers the causal case might seem tangled. Wasn’t Faraday’s genius a prerequisite for field theory to flourish? Hunt does not deny it, but he foregrounds the engineering.
The story of the transatlantic cable is one of many failures. As Hunt recounts in Imperial Science, the early engineering efforts for undersea cables were invariably crude, and it is remarkable that these efforts succeeded at all. Installing the first cable across the English Channel, “the Bretts’ chief engineer, Charlton Wollaston, reportedly sometimes used his tongue to check for the flow of current.”17
The wonderfully named Wildman Whitehouse and William Thomson, who later became Lord Kelvin, worked together on the first transatlantic cable for the Atlantic Telegraph Company. Whitehouse was, as Hunt puts it, “an avid measurer, but it was not always clear quite what he was measuring.”18 Only a few weeks after the cable connecting Ireland to Newfoundland was completed in August 1858, it failed. The failure was largely pinned on Whitehouse, who was left “isolated and vulnerable” by the obscurity of his methods. By contrast, Thomson standardized his measurements with those of other engineers. Although the physicists at the heart of this story did not always agree on scientific matters, they were all united in their support for precision measurements.
Other undersea cable failures included a failed imperial project for a cable beneath the Red Sea, which collapsed in 1860 and left the British public footing the bill. Without the needs of the empire, Hunt argues, the British might not have pushed forward. But the desire for quick communications from London to Egypt, and then on to India, made it important to know what had gone wrong.
Were fundamental difficulties at the root of these failures, or just incompetent executions? The turning point for undersea telegraphy, in Hunt’s version, involves committee work. This doesn’t have quite the same drama as the tales of sailors dragging cables through the rough sea, but such efforts convinced cable engineers once and for all that their goals were feasible. The Joint Committee to Inquire into the Construction of Submarine Telegraph Cables, formed following the 1858 failure, was a collaboration between the telegraph companies and the British government. In their report, published in 1861, the committee found, in short, that there were no fundamental difficulties with undersea telegraphy. But lessons had been learned. The high voltages that Whitehouse had used likely contributed to the transatlantic cable’s failure. And the quality controls that Thomson had introduced would need to become industrial standards.
The Joint Committee Report compiled these lessons and “became the bible of the cable industry.”19 Predictably, the Joint Committee birthed another committee, the Committee on Standards of Electrical Resistance. This new committee, founded in 1861, would include Maxwell as a member. Hunt argues that Maxwell’s experiences on the committee would change the direction of his research—and hence the direction of electromagnetic theory.
The principal goal of the Committee on Standards was to establish reliable methods for measuring for electrical resistance. The importance of this task was underlined after Thomson discovered that material impurities could cause cable resistances to vary widely. The Committee on Standards had to balance conceptual innovations with existing practices.20 The committee scientists preferred resistance units that conceptually linked resistance to energy dissipation, while engineers preferred units that referred to some standard device, such as the meter-long coil of mercury that Siemens had introduced in continental Europe. To synthesize these competing requirements, the committee ultimately settled on the British Association (B.A.) unit, equal to 1.98 ohms in today’s SI units, and matching the Siemens mercury unit to within about five percent.
The job of creating a resistance standard for the B.A. unit—intended as a better-theorized competitor to the Siemens mercury coil—fell to Maxwell and his engineering associates. Maxwell only wrote one coauthored paper related to his committee work, “On the Elementary Relations between Electrical Measurements.”21 Yet Hunt argues that it marked a turning point for Maxwell—and hence a turning point for the history of physics.
Before he came to work for the Committee on Standards, Maxwell had himself pursued mechanical models of the ether, including a vortex model whose spinning components were supposed to cause the effects of the magnetic field. Hunt argues that Maxwell never gave up the idea that elements like these must ultimately underlie electromagnetic phenomena. But in “Elementary Relations,” Maxwell and his coauthor Fleeming Jenkin kept to what could be surmised from only experimental facts and dimensional analysis. Working in this way, Hunt argues, “brought home to [Maxwell] the value of framing his results not just in terms of unseen microstructures but as far as possible also in terms of relations among measurable quantities”—a surprisingly modern approach.22 By sidestepping any details of the ether’s microstructures, Maxwell’s theory was able to outlive the Victorian era.
Having summarized this story, it feels somewhat perverse to describe Imperial Science just in terms of its arguments. Certainly, the book contains arguments—from how geography contributed to Britain’s supremacy in early field theory, to why Maxwell backed away from explicit models of the ether. But these often seem to be filler between the newfound facts. Most of Imperial Science is built on solidly sourced claims, marching one after another, telling us who suggested which course of action, which course of action was taken, and so on.
By the end, readers reach the episodes in 1865 and 1866 when the Atlantic Telegraph Company tried again, and ultimately succeeded, in installing a transatlantic cable. Hunt’s timeline finally catches up to that of his first book, with Oliver Heaviside rewriting Maxwell’s theory in the 1880s and extending the theory of telegraphic signal propagation to include magnetic induction. As a direct result of his understanding of Maxwell’s theory, Heaviside proposed loading coils as a partial fix to the smearing of retarded signals, in a foretaste of the theory-driven era of technological acceleration to come.
Is there any moral to be drawn from the story? In the epilogue, Hunt offers this:
Scientific knowledge is inescapably contingent: the picture scientists form of the world depends on the evidence they encounter and the weight they give to it. This evidence is typically mediated through various technologies—whether scientific instruments or technologies devised for more practical ends—that consequently shape the theories scientists (and others) form to account for what they see.23
Field theory, in other words, is not the necessary container for the sorts of phenomena traditionally grouped within electromagnetism, but the outgrowth of a particular set of historical circumstances that included undersea telegraphy and the British Empire. Hunt does not push this claim in any particular direction. There is something unsatisfying about this. When a modern intellectual labels something as the product of imperialism, one expects a denunciation to follow—or perhaps a contrarian defense. Hunt makes no such move. He asks readers neither to decolonize field theory nor to celebrate the imperial context of its birth.
Physicists may see their Victorian counterparts as displaced colleagues, but in a book such as Imperial Science, the Victorians remain inextricably trapped in their own era, like insects in amber. Yet for those who pursue science as scientists, questions about which aspects of our disciplines reflect nature and which reflect culture are never really settled just by plumbing the history. We can only continue to grope our way forward, past the illumination of our forebears, onto the paths we build into the dark.
