The Roots of Progress

The significance of the steam engine

April 8, 2017

Before the steam engine, if you wanted to generate useful motion—to grind wheat, to saw logs, to pump water—you had to rely on natural forces. You could harness wind or water, with mills. Or you could use muscle power—from domesticated animals, or failing all else, on your own.

But all these sources of energy, by themselves, have serious limitations. Wind and water are not portable: you have to go where they are, and their energy cannot be used elsewhere. Wind, especially, is unreliable: the wind blows when it wants to, and you can’t turn it on or off. And all of them are limited: you can’t make the river stronger, or design a more efficient horse.

Separately, for many thousands of years, mankind was in control of fire. We could create heat by burning fuel, such as wood or coal. But in 1700, these two had nothing to do with each other.

The significance of the steam engine is that it was a way to turn heat into motion. With this ingenious device, we could now use fuel instead of wind, water or muscle power. In fact, the Newcomen engine was originally called a “fire engine”.

Fuel can be transported, so engines can operate anywhere. Fuel can be burned at any time, and can be started and stopped at will. If you need more energy, you can use more fuel—as much as you can afford. And through mechanical innovations, we can improve the efficiency and the power of engines.

So the steam engine solved all of the problems with natural forces at once. I’m still early in my reading, but that, it seems to me, is why the steam engine was such a turning point and why it kicked off the Industrial Revolution.