• DOI:10.1086/368729
• Corpus ID: 145557228

The Ohm Is Where the Art Is: British Telegraph Engineers and the Development of Electrical Standards

@article{Hunt1994TheOI,
  title={The Ohm Is Where the Art Is: British Telegraph Engineers and the Development of Electrical Standards},
  author={Bruce J. Hunt},
  journal={Osiris},
  year={1994},
  volume={9},
  pages={48 - 63}
}

• B. J. Hunt
• Published 1 January 1994
• History
• Osiris

T HE HUMBLE RESISTANCE BOX has been central to the daily work, and crucial to many of the most outstanding achievements, of both physicists and electrical engineers since the middle of the nineteenth century. Without the ready availability of accurate and reliable resistance standards, the precision electrical measurement that underlies so many areas of science and technology would be virtually impossible. As Fleeming Jenkin, himself a pioneer in the development of the standard ohm, observed in 1865, "Resistance-coils ... are now as necessary to the electrician as the balance to the chemist." I Standard resistances-ohms-have become so ubiquitous as to be almost invisible; they are now simply taken for granted. But how did they achieve this virtually unquestioned authority? Who undertook the immense labor necessary to secure the first reliable standards, and why? In particular, what role did the practical concerns of British telegraph engineers play in the origin of the ohm, and to what extent did the early standard coils in fact embody their aims and expertise? Two quotations from William Thomson (later Lord Kelvin) and James Clerk Maxwell will shed some light on these questions. In a lecture on "electrical units of measurement" at the Institution of Civil Engineers in 1883, Thomson declared that British cable engineers had been ahead of physicists in the practice of accurate electrical measurement from about 1860 to the early 1 870s. "Resistance coils and ohms," he said, "and standard condensers and microfarads, had been for ten years familiar to the electricians of the submarine-cable factories and testing-stations, before anything that could be called electric measurement had come to be regularly practised in almost any of the scientific laboratories of the world."2 And in a review of Jenkin's 1873 textbook Electricity and Magnetism, Maxwell said that "at the present time there are two sciences of electricity-one that of the lecture-room and the popular treatise; the other that of the testing-office and the engineer's specification. The first