"Larry Jaques" wrote in message
Did the concept of partial pressure come about to service the needs
of
those who physically fill tanks of gas, I wonder?

Nope.

Along with the other gas laws it dates from ~1800 when amateur
experimenters finally made sense of chemistry.
http://en.wikipedia.org/wiki/Dalton's_law
http://en.wikipedia.org/wiki/Antoine_Lavoisier

It was an enormous leap from a level not that much higher than the
Romans. Science was pretty much still mystic alchemy in 1780, by the
1820s we understood electricity, magnetism and thermodynamics and that
Earth, Air, Fire and Water weren't the basic elements of matter, but
levels of energy. Likewise that's the period when metalworking
advanced from saws and chisels to lathes, planers and milling
machines.

jsw