Steam Engine (Civ1)

Steam Engine allows the building of ironclads, the first powerful military sea vessel.
It is a prerequisite of railroad.
== Civilopedia entry ==
Some of the properties of steam have been known since ancient times, but it took thousands of years of groundwork in Physics and the practical skills of a few Inventors to build a working Steam Engine. The beauty and value of this engine was that it could do the work of many men. A Steam Engine operator could have his strength multiplied enormously by tapping the heat energy released by burning coal. The Steam Engine was the prerequisite for the Industrial Revolution, leading to the spread of Factories and Railroads around the world.