Decorative Initial K nown variously as “the Magnetic Crusade” and “the magnetic scheme,” this early Victorian project studied the earth’s magnetism--a pervasive, invisible force on which navigators and surveyors depended yet that at times behaved erratically, as when, for instance, mysterious "magnetic storms" unexpectedly bedeviled compass needles and magnetometers. Victorian magnetic researchers aimed to produce charts and maps of global magnetic variation and correlate these observations with observations of other atmospheric phenomena such as solar flares. By means of this project, which was in force from 1839-47, scientists hoped to develop a theory to explain fluctuations that had been observed in magnetic instruments for centuries. One practical goal was to improve these instruments for the purposes of navigation and surveying; but there was also the not inconsiderable to desire for, as W. Vernon Harcourt put it, “the revelation of new cosmical laws” governing this global phenomenon (quoted in Cawood p. 493). William Whewell famously called the project, among the largest of the century, “by far the greatest scientific undertaking the world has ever seen” (quoted in Cawood, p. 493).

This grand ambition linked the project to a broader shift, pioneered a generation before, by the Prussian naturalist and explorer Alexander von Humboldt (1769-1859). Humboldt sought laws and constants relating to global phenomena such as weather, geomagnetism, geographical distributions of plant and animal life. This approach, which historian Susan Faye Cannon influentially described as “Humboldtian,” contrasted with scientific work undertaken in a less theoretically driven, Baconian vein. Yet this style of scientific work was also deeply empirical. In his celebrated travels around the world, Humboldt measured a wide variety of natural phenomena, collecting many kinds of data from meteorological astronomical and magnetic to botanical and zoological. But he always did so with the goal of producing theories that could account for regularities he observed in these massive collections of data. As the historian Michael Dettelbach has pointed out, the early Victorian ambition prompting the worldwide study of geomagnetism was hardly a full and complete transmission of Humboldt’s ideas, but was rather more like a translation of them. As Cannon showed, adherents of this broadly Humboldtian view in Britain formed a network that linked scientists, many of whom were affiliated with the British Association for the Advancement of Science (BAAS), with Broad Church adherents, in opposition to what all involved saw as excessive ritualism and scholasticism among their High Church contemporaries.

The British magnetic scheme was large, complex, and expensive. Colonel Edward Sabine at Woolwich and Humphrey Lloyd in Dublin came together to organize the scheme; with John Herschel and a small number of others, they had worked throughout the 1830s to make terrestrial magnetic observations a regular part of scientific work and to develop better instruments for making measurements; they also developed regional schemes such as the first magnetic survey of the British Isles, during that period. As the project developed, institutional support widened to include the BAAS and the Royal Society, and its leaders, especially Herschel, advanced specific campaigns, such as an expedition to the southern hemisphere to generate the data needed to produce a more comprehensive theory to account for the behavior of the earth's magnetic field (Carter 47-71).

Measurements were made in geographically fixed colonial and company observatories and on traveling surveys. Traveling surveys included the Antarctic expedition, 1839-1843, of James Clark Ross (1800-1862), the North American Magnetic Survey of 1843-44, and the Canadian Arctic expeditions of Sir John Franklin (1786-1847), Henry Maxwell Lefroy (1818-1879), and George Strong Nares (1831-1915). Fixed stations included the colonial observatories at Toronto, St. Helena, Van Diemen’s Land, and the Cape of Good Hope; and at royal and company observatories in India and elsewhere in the colonies. The colonial observatories were staffed by the Royal Artillery and, at Van Diemen’s Land, by the Royal Navy; all were under the supervision of the Board of Ordnance (though Van Diemen’s Land did not come under Ordnance supervision until 1841; Goodman 188).

British and colonial observations were supplemented by observations from observatories in Europe, Russia, and the United States, creating a global network. Measurements were taken according to a common protocol. Instruments included magnetometers of several kinds; an inclinometer or dip circle, to measure how much a magnetized needle inclined toward the earth at a given point; and a variety of other, less specialized instruments including theodolites, clocks, and barometers. Staff took measurements every two hours around the clock, every day except Sunday; on monthly “term days” additional measurements were taken every two-and-a-half minutes for twenty-four hours. Observations were recorded in various register books which were then sent by participating observatories to Sabine at Woolwich, where they were laboriously tabulated and reduced by hand, using pencil and paper, and prepared for publication (Goodman 188).

Links to Related Material

Bibliography

Cannon, Susan Faye. Science and Culture: The Early Victorian Period. New York: Dawson, Folkestone, and Science History Publications, 1978.

Carter, Christopher. Magnetic Fever: Global Imperialism and Empiricism in the Nineteenth Century. Philadelphia: American Philosophical Society, 2009.

Cawood, John. “The Magnetic Crusade: Science and Politics in Early Victorian Britain.” Isis 70 (1979): 493-518.

Dettelbach, Michael. “Humboldtian Science,” ed. N. Jardine, J. A. Secord, and E. C. Spary, Cultures of Natural History. Cambridge: Cambridge University Press, 1996. 287-304.

Goodman, Matthew. “Follow the Data: Administering Science at Edward Sabine’s Magnetic Department, Woolwich, 1841-57.” Notes and Records of the Royal Society 73 (2019): 187-202.

Ratcliff, Jessica. “Big Science in Britain, c. 1815-1870.” The Transit of Venus Enterprise in Victorian Britain. Pittsburgh: University of Pittsburgh Press, 2016. 21-34.


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Last modified 28 July 2023