On the History of Heat Engines

Drawing of Watt's steam engine
From: Encyclopedia Britannica

It is no question that the invention of the first steam engine by James Watt in 1769 was a milestone in human history. It certainly changed our way of life: Initializing industrial revolution, goods could be produced in vast amounts, enabling consumerism. But even more: Suddenly wood, and later coal was needed in great quantities so that mankind changed the look of our planet irreversibly. In that sense, one might even say that the invention of the engine had a greater impact on human live than such prominent discoveries like fire, or the wheel! 
Certainly, there is a lot more to be said concerning the historic and social dimension. In this blog entry I would simply like to refer the reader to two historic documents. 
The first one is the original paper of Carnot, who describes his famous Carnot-cycle and computes the maximum efficiency of a heat engine. Sure it is interesting reading for its own sake put I want to stress two things I found truly amazing: First, Carnot was quite certain that the things he was doing will change the world. In his own words: "Heat engines are destined to produce a huge revolution in the civilized world" - a bold statement but history proved him right. Second and this came as a real surprise to me: Carnot was not aware of the fact, that heat (or as he calls it: caloric) is simply energy stored in fast motional degrees of freedom. He still thought of heat as being some kind of strange fluid, always flowing from hotter to colder regions. But still, although having the wrong picture in mind, he still obtained the right conclusions! So again, (almost ;-) nothing to complain about.
The second historic document is simply James Watt's original patent. Maybe less scientific content, but simply fun to read, especially for its references to King George the Third.