>> > The very first steam engines had a piston that was several FEET in
>>
>> > And they worked at '0' PSI steam pressure.
>>
>> "0" can be measured. If you have "0" PSIG, then you don't have
>> steam. Now pressure measured in inches of water column, (in.W.C.) is
 
> Wayne,
> You missed the first part of my story. Those early steam engines did, in
> fact, work at '0' steam pressure. The purpose of the steam was to
> displace the air. Water was then sprayed into the cylinder to condense
> the steam, causing a vacuum, so that the atmospheric pressure on the
> other side would cause the piston to stroke.
 
> Yes, it might have had a measurable pressure in inches of water column,
> but the effective pressure was essentially '0'.
 
And again, water vapor at "0" PSIG is NOT steam.
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