On Jul 16, 9:27*pm, Andy Dingley wrote:
On Jul 16, 7:07*pm, harry wrote:

On Jul 16, 10:24*am, Guy Gorton wrote:
No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on vacuum.http://en.wikipedia.org/wiki/Atmospheric_engine

FFS! *Don't believe _anything_ on Wikipedia!

The staem was used to flush air out of the cylinders. When it was
condensed (By a water jet) the piston was"sucked down"by the resultant
vacuum.
Hence "atmospheric."

So some a litte boy would operate the valves manually. A big advance
was automatic operation.

Don't you know anything?