Today, meet the person who reinvented Archimedes'
pump. 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.
The common mythology says
that engineering and philosophy are separate
disciplines. To believe that, we have to close our
eyes to the way machines shape themselves to our
outlook. The truth is, technology and philosophy
each bend to fit one another.
Here's an example: Archimedes invented a really
clever pump in the third century BC. It's been used
all over the world ever since. It looks like a tube
coiled around a long axle. You tilt the axle and
put its lower end in water. Then you turn it. The
open end of the tube picks up water and, as the
coil turns, water passes from one loop to the next
until it comes out at the upper end.
It's a very subtle gadget. It's not, as one author
put it, something that would be created
spontaneously by peasants. Archimedean pumps were
widespread in the Classical world. Roman authors
described them. Well, they tried to. We've just
seen that they are not easy to describe.
Archimedes' pump did poorly in the High Middle
Ages. Europeans had just rediscovered Aristotle and
had strongly bought into his science. Aristotle
clearly separated motion into two kinds -- straight
line motion and rotary motion. An Archimedean pump
used rotation to move water upward along an axis.
Because it mixed the straight-line and rotary
motion, it made engineers of the late Middle Ages
and early Renaissance very uncomfortable.
By 1565 those pumps were so little known in Europe
that an agricultural engineer named Giuseppe Ceredi
received a patent for one. Ceredi systematically
described the installation of arrays of these pumps
for both irrigation and drainage. Naturally we
wonder how he could get a patent for a device that
was known in books.
But then we compare Ceredi's dimensioned drawings,
flow calculations, and economic analysis with the
almost unreadable Roman descriptions. Ceredi may or
may not've found the idea in the old literature.
But, whether he did or not, he had to do a great
deal on his own to make it work.
Ceredi clearly had a right-brain ability to
visualize, coupled with a left-brain ability to
execute and organize detail. That's what it took
for him to overcome a philosophically ingrained
resistance to an idea. After Ceredi, these pumps
quickly gained acceptance across southern Europe.
He'd broken the straitjacket of an old way of
thinking.
A few years later, Galileo took up full-scale
combat with Aristotelian ideas of motion. When
Galileo wrote his theory of the pendulum, for
example, he first had to break with old ideas about
falling. Aristotle would've said that the weight on
a pendulum was simply an object experiencing great
difficulty in falling.
So Ceredi's reinvention of Archimedes' pump was, in
fact, a harbinger -- so much more than mere means
to a practical end. It really was a stalking horse
for a major philosophical revolution.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
Drake, S., An Agricultural Economist of the Late
Renaissance. Humana Civilitas, Vol 1, On
Pre-Modern Technology and Science, A Volume of
Studies in Honor of Lynn White, Jr. (Bert S. Hall
and Delno C. West, eds.) Malibu, CA: Undena
Publications, 1976, pp. 53-73.
This is a greatly revised version of Episode 116.
From the 1832 Edinburgh
Encyclopaedia
A Spiral of Archimedes, or Archimedean
pump
One of Ceredi's sketches showing an Archimedean
pump equipped with a flywheel to sustain its
rotation
The Engines of Our Ingenuity is
Copyright © 1988-2000 by John H.
Lienhard.
