KEYNOTE 1: If the temperature of the heat is higher than the surroundings, the higher ‘temperature fall’ through an engine, the higher the motive power will be (the more power per unit of heat flow, the more efficient engine), analogous to the higher power from more “elevation-fall” from a higher elevation through a waterwheel per unit of water flow. In Sadi Carnot’s words, “The temperature of the fluid should be made as high as possible, in order to obtain a great fall of caloric, and consequently a large production of motive power [1]”.