This might be useful for the devs since they're going to be adding all sorts of steam powered devices. Water cannot be compressed, but steam can. Steam will expand to a volume 1600 times greater than water and exert corresponding pressure if it cannot. Steam power is inherently dangerous for the enormous pressure within the boiler. Boilers must be sturdy to withstand the pressure. The other reason why steam engines are dangerous is the temperature of the steam. While water boils at 100 °C, steam engines operated at higher temperatures (up to several hundred °C). Most importantly, steam carries a lot of thermal energy. To heat water from 99 °C to 100 °C requires much less energy than heating steam from 100 °C to 101 °C and as a result, steam burns are much more severe than the temperature of the steam would indicate. You probably already know this from household experience: 100 °C steam from a kettle is unbearably hot and will give you burns, whereas reaching into 200 °C oven is doable for a few seconds (as long as the air inside has low humidity). Early steam engines were prone to explosions until engineers managed to create pressure relief valves, which automatically release excess pressure. Depending on how sophisticated team power is in Clockwork Empires, a catastrophic failure would either be attributed to a defective pressure reflief valve or some worker in charge of manually relieving pressure not paying attention. Superheated steam is interesting. If you heat steam past its condensation temperature, then it becomes invisible. Superheated steam is also called "dry steam" and is particularly useful for efficient power generation via steam turbines (as opposed to piston based steam engines). Modern turbines in coal or nuclear power plants are run are driven with dry steam. Steam turbines were invented in 1884 according to Wikipedia.
God I can´t hear that fact anymore: YES, water can be compressed. It just takes a huge amount of pressure. If water couldn´t be compressed then you could throw an ocean at a black hole and it would stay a ocean with the same measurments, which it doesn´t it would be compressed by the gravity like everything else. Also: If you can decompress something you can also compress it. Or else decopressed water would just expand without ever getting back to it´s natural state. For example the water at the bottom of the ocean has a higher desity as the water near the surface, because the weight of the water above it comresses it.
For most intents and purposes, water should be considered incompressible. Quoting http://en.wikipedia.org/wiki/Water_(molecule) 40 MPa is 394 atmospheres by the way.
Saying that water can't be compressed is like saying that a brick is solid - it's really more empty space than stuff, but it's probably a more useful heuristic - and more accurate for everyday purposes - than chucking out a wiki paragraph whenever you want to discuss water's compressibility.
Like I said, it takes a high amount of energie. But saying water is incompressible is like saying that atoms can´t be split.
Clockwork reminder : The Clockwork Empire world is based on lunatic assumptions and nonsense of the XIXth century mad men and cons calling themselves scientists, as well as dangerous ideas and musings of some horror-fantasy fiction authors of the early XXth century. Devising about water and atoms and black hole is all good, but kinda miss the point that science, and therefore the rules of physics, in CE are distorted to a high degree. We're talking about a world where you can produce steam "via clean-burning madness", whatever that means.
Very clearly, this refers to the burning of insane cultists to summon ungodly creatures that you then burn to produce infinite amounts of energy... Assuming the cultists or ungodly creatures don't burn you first.
