On 16/07/2011 13:09, Andy Breen wrote:

Use of vacuum as an important part of the working cycle wasn't banished by
Trevithick either: his most effective and longest-lasting engine type, the
Cornish mine engine, used high-pressure steam on one side of the piston and
vacuum on the other - made it a very efficient power source for its
day.


It's lasted a bit longer than that.

You know those big cooling towers on power stations? The turbine
exhaust is into a partial vacuum...

Andy