George Eliot's novel _The Mill on the Floss_ is set at a water-powered mill during the 1830s, the decade of decisive transition to coal within British industry. This article examines the dual temporalities of Eliot's novel from the perspective of energy and ecology, showing how the novel identifies the distinct temporal profiles of a water-generated versus a steam-generated economy. As a fictional account of the transition from water power to steam, the novel attends to the temporal limitations of individual understanding, especially as it relates to the steam-fueled fantasy of permanent growth.