Reviewed by: Imperial Science: Cable Telegraphy and Electrical Physics in the Victorian British Empire by Bruce J. Hunt Andrea Giuntini (bio) Imperial Science: Cable Telegraphy and Electrical Physics in the Victorian British Empire By Bruce J. Hunt. Cambridge: Cambridge University Press, 2021. Pp. 320. The development of telegraphy through submarine cables in the second half of the nineteenth century was a major episode in economic history, in terms of imperial power, invested capital, financial risk, technological challenges, and the involvement of public opinion. Submarine cables served political and military goals and stimulated the integration of economic and entrepreneurial activities of traders, bankers, insurance brokers, and those engaged in shipping. This winning combination of science and technology on the one hand, and entrepreneurial initiative on the other, fully reflects the leadership of the Western world at the time of imperialism. The first submarine cable was laid on the bottom of the sea between Dover and Calais in 1851; it was the outcome of extensive study and experimentation. It led scholars and entrepreneurs to envisage a cable across the ocean aimed at the American continent, which was accomplished in 1866. Once the oceanic depth was conquered, cable technology reached a level of standardization allowing a worldwide diffusion of the submarine network. Between 1850 and 1870, submarine telegraphy progressed significantly and reached technological maturity. Installation of the cables entailed extensive and difficult work. Design and construction were not the only complex stages of submarine connection: it was also necessary to transport the cables, weighing several tons, and lay them on an as-flat-as-possible deep sea floor by submerging them with the utmost care using pulleys. The transmission of electric impulses, subsequently converted into signals, through a cable submerged in deep water, posed an enormous technical and scientific challenge. Experiments in submarine telegraphy boosted research in the field of electrical measurement. These were led by a new class of engineers, working with great passion and commitment, who made electrical technologies part of the Victorian culture. Electrical standards were established in response to several failures. The core of this scientific development lay in studies on the conductivity of copper wires—their resistance differed considerably and they defined the quality of the signals. British scientist William Thomson (Baron Kelvin) understood that it was more relevant to focus on reception than transmission. From this observation in 1857, he determined the need to understand electrical measurement as a means of quality control. The identification of standards completely changed the perspective in this field, both for the manufacturers of cables and the technicians laying them. Experimentation in the submarine telegraph [End Page 576] sector contributed significantly to the maturity of a new generation of engineers, decisive for the subsequent expansion of a scientific engineering concept that became the soul of the second industrial revolution. In those years, the best engineers in the electricity sector passed through the world of telegraphy, producing many studies, and stimulating the standardization of a technology considered completely futuristic only a few years earlier. A new international community of specialists emerged, who by the nature of their expertise connected continents. A feverish circulation of ideas in places dedicated to scientific debate—books, newspapers and journals, conferences—is evidence of the intense collaborative activity aimed at the feasibility of laying a cable under the Atlantic. Hunt's book contributes to a historiography which already consists of excellent works. The book is based on a variety of sources, including archival material, official documents, popular magazines, leading newspapers, and the extensive existing literature. He tackles the subject from the point of view of the history of science and technology, underlining the contribution of key figures, mostly British. He has a profound technical knowledge of the subject and provides a clear overview of the physicists and electrical engineers involved, the role of scientific associations, and the narrow ties that linked the cable industry to electrical physics. The added value of the book is in providing evidence, as no other authors have done so far, of the technological steps leading to the great telegraph connection across the Atlantic and later around the world. Hunt also makes the various themes understandable to non-experts, building a compelling and well...