The caloric theory's an obsolete scientific theory that heat consists of a fluid called caloric that flows from hotter to colder bodies. Caloric was also thought of as a weightless gas that could pass in and out of pores in solids and liquids. The "caloric theory" was superseded by the mid-19th century in favor of the theory of heat but nevertheless persisted in scientific literature until the end of the 19th century. Early history In the history of thermodynamics, the initial explanations of h… (More on Caloric)