Today, we finally get back to where we started. The
University of Houston's College of Engineering
presents this series about the machines that make our
civilization run, and the people whose ingenuity
created them.
Technology has an odd way of
starting out where it will one day end up -- of
wandering all over the map before it gets there.
Take the earliest writing, done with a stylus on
clay tablets. Now, 5000 years later, we've gone
from clay through papyrus, sheepskin, and paper, to
increasingly dense magnetic storage. Finally, CD
ROM brings us back to engraving -- first on metal.
But now, in the quest for permanence, we're
learning to micro-engrave words on ceramic
surfaces. So, it seems, we've come full circle.
That's how it was with steam power. In the 250
years before Cleopatra, the Egyptians created all
kinds of steam-driven toys. They all worked on the
same principle: they had small water tanks heated
by a fire. Steam escaped through jets to drive the
toy.
But no one could quite figure out how to make steam
jets produce useful power. Finally, in the early
1700s, English engineers came up with a completely
different scheme for getting power out of steam.
They used steam to drive pistons. Soon, the whole
world was powered by piston steam-engines, and
those Egyptian jets were forgotten.
But then, in the 1880s, we had to drive our new
electric generators. Generators turned faster than
a big piston could move. The answer was to blow
steam jets onto fast-turning propeller blades. We
created the steam turbine. And that's what we use
to take power from steam today, even in nuclear
plants. Like cuneiform on clay, those ancient
Egyptian jets had finally come back.
Historian Joseph Needham underscores that point.
Before England gave us piston engines, the Jesuits
were a strong presence in China -- teaching,
learning, and ordaining priests. In 1671 one of
those priests, Min Mingwo, built a set of
steam-driven model boats and cars to entertain his
emperor. His boilers supplied steam jets. They fell
on fast-turning paddle-wheels which drove gear
trains to slow their motion and power the vehicles.
Mingwo had created a complete functioning steam
turbine. And he did it well. His model car ran,
nonstop, for two hours. There's a working
reconstruction of Mingwo's car in the Milan science
museum. It's the prototype of a machine poised to
transform the world.
But it didn't. In 1671 we still weren't ready for
this 2000-year-old idea. Eighteenth-century England
turned instead to piston engines for her mills and
mine pumps. Steam jets could no more have gone
straight from the court of Cleopatra, or the
Chinese emperor, into modern service than cuneiform
writing could.
So I think about those first unfinished ideas: the
airplane with flapping wings, a cannon launching a
satellite. That first idea has the oddest way of
coming back at the end -- just when we least expect
it.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
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