In 1775, Alessandro Volta announced the invention of the electrophorus, a device that could be electrified once and produce a seemingly endless supply of electricity through the repetition of a simple series of operations. The device was regarded as a mystery, the most surprising invention since the Leyden jar (1745), and just as the Leyden jar had thirty years earlier, it was thought the electrophorus would revolutionize electrical theory and reinvigorate waning interest in electricity among natural philosophers. Today the electrophorus is widely regarded as having contributed to an important shift in the scientific consensus regarding how electrical attraction and repulsion were thought to work and as having opened the door for action at a distance models of electricity.

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Despite the electrophorus’s importance in the history of electricity, prior scholarship has not attempted to explain why the electrophorus had such a large impact on electricians. As it turns out, Volta was not the first experiment to demonstrate the seemingly endless sparks that electricians found so mysterious, as detailed analysis of the experiments of Johan Carl Wilcke (1762) and Giambatista Beccaria (1772) reveals. In addition, the theoretical changes that the electrophorus caused were anticipated by theorists in largely underappreciated works as early as 1759. The electrophorus was nevertheless something genuinely new and its success can be explained in terms of several design features that allowed it to gain wider distribution and demonstrate its phenomena more clearly than prior experiments. Ultimately, the story of the electrophorus is a story of how the scientific consensus in an area is set and what it takes for the consensus to change.