In 1729, the English astronomer and dyer Stephen Gray discovered electrical conduction through a series of experiments conducted in London. He demonstrated that static electricity could travel along lengths of string, wire, and wet packthread over distances of hundreds of feet, and he classified materials as either conductors or insulators. Gray's discovery fundamentally changed the understanding of electricity from a property of specific objects to a fluid-like entity that could move through matter.

Gray's discovery that an invisible force could travel invisibly through space and matter fascinated the literary imagination of eighteenth-century England. The image of an unseen current flowing through a thread became a potent metaphor for the transmission of feeling, thought, and influence between people, a metaphor that would reach its fullest expression in Romantic poetry's language of sympathy, sensibility, and the "electric chain" of human connection found in the works of Wordsworth, Coleridge, and Shelley.