Centuries ago, apart from any scientific theory, creative individuals like Archimedes, developed six simple machines to make ‘work’ easier. These simple machines do not produce energy but change the relationship between force time and distance.
The six mechanical principles are still widely used in modern mechanical engineering. The six machines origin from purely experience based know how.
In chapter VIII of his book, Maxwell discusses the functioning of the heat engine in a theoretical framework.
“Carnot himself was a believer in the material nature of heat, and was in consequence led to an erroneous statement of the quantities of heat which must enter and leave the engine. As our object is to understand the “theory” of heat, and not to give an historical account of the theory, we shall avail ourselves of the important step which Carnot made, while we avoid the error into which he fell”.
James Clerk Maxwell.
The French engineer Said Carnot was more focused on the mechanical aspects of the machine in the conversion of heat to motion than Maxwell was. Thomas Kuhn is right in saying that ‘the concern with engines’ is an important ‘trigger factor’.