In 1843, the English physicist James Prescott Joule published the results of his paddle-wheel experiments in Manchester, demonstrating that mechanical work could be converted into heat through the friction of an electrically driven paddle stirring water. By carefully measuring the temperature rise, Joule determined the precise mechanical equivalent of heat, showing that electrical, mechanical, and thermal energy were interconvertible. This work, conducted in his laboratory in Manchester, laid the foundation for the law of conservation of energy.

Joule's demonstration that all forms of energy were fundamentally equivalent reinforced a unifying vision of nature that deeply influenced Victorian literature's philosophical underpinnings. The conservation of energy suggested that nothing was truly lost or destroyed, only transformed, a concept that resonated with Victorian poetic themes of immortality, spiritual continuity, and the persistence of love beyond death. The Manchester industrial context of Joule's work also connected it to the literature of the Industrial Revolution, including Elizabeth Gaskell's novels set in the same city.