The history of heat has a prominent place in the history of science. It traces its origins to the first hominids to make fire and to speculate on its operation and meaning to modern day physicists who study the microscopic nature of heat. The phenomenon of heat and its definition through mythological theories of fire, to heat, to Terra pinguis, phlogiston, to fire air, to caloric, to the theory of heat, to the mechanical equivalent of heat, to Thermos-dynamics (sometimes called energetics) to thermodynamics. The history of heat is a precursor for developments and theories in the history of thermodynamics.