Empire-Laden Theory: The Technological and Colonial Roots of Maxwell’s Theories of Electromagnetism

James Clerk Maxwell’s theories of electromagnetism are distinctively Victorian products. Analysis of his often ignored theory of electric absorption and the Maxwellians’ “leaky condenser” reveals that critical details of these theories were shaped by Victorian electrical technology, namely capacitors and undersea telegraphy. Between appearances in his “Dynamical Theory” and Treatise, Maxwell’s theory of electric absorption evolved. It shifted his understanding of electrical action in the dielectric, bolstered central concepts in his broader electromagnetic theories, provided hope for a beleaguered experimental program to confirm his electromagnetic theory of light, and even led him to distort his expression for Ohm’s law. Simultaneously, the technological influences behind his theories come with their own histories. Maxwell draws heavily upon the testimony of cable engineer Fleeming Jenkin to the Joint Committee on the Construction of Submarine Telegraphs, formed to rescue the industry after multiple failed attempts to lay an Atlantic cable. Maxwell’s reliance on this testimony given to this committee imprints the financial and imperial ambition that initially spurred these cables’ construction onto his electromagnetic theories. A substance discussed in this testimony, gutta-percha, also connects Maxwell’s theory to the extractive global trade of this resource. The success of this committee in reforming the telegraph industry links Maxwell’s theories to the colonial, economic, and ecological fallout of the rapid global expansion of Britain’s undersea telegraph network.