Today, we look for technology that can blow our
troubles away. 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 great weekly event
during 1942 was Saturday afternoon at the Uptown
Theater. Forty cents bought a bag of popcorn, a box
of Milk Duds, and a movie ticket. I sat in the dark
and watched young Ronald Reagan flying his airplane
against terrible odds. Each week, it seemed, he
shot down the same Chinese actors clad in Japanese
uniforms; and America stayed safe for democracy.
Death was bloodless in the Uptown Theater. The
enemy was mowed down from afar. Bullets, like laser
beams, eliminated peril while it was still distant.
They didn't actually break the skin. The bad guys
were killed. Only the good guys were merely
wounded, and they healed before the next battle.
Weapons in the Uptown Theater were like fictional
death rays. You pointed a gun, and the enemy fell
down. You dropped a bomb, and a bridge disappeared.
It wasn't until 1947 that we began to learn what
those bombs had really been doing.
So we aren't too surprised when we hear an enduring
myth of early technology. According to the story,
Archimedes created a huge mirror. He focused the
sun's rays on the Roman fleet as it invaded
Syracuse. He set it on fire from the distance of a
bow shot. That tale has gone in and out of favor
with historians ever since. Now physicist D.L.
Simms gives us his careful analysis.
Simms thinks the story hangs on the edge of
plausibility. Archimedes might just barely have
known enough optics to make such a mirror. It's
conceivable that he could have made it with an
adjustable focal length. He might even have been
able to keep a beam fixed on one spot long enough
to ignite wood. But beyond all those terrible if's
was the fact that the burning mirror didn't appear
in the earliest accounts of the battle. The first
versions tell us only that Archimedes's ingenuity
had something to do with winning the battle and
that fire was involved.
Simms concludes that the burning mirror was a
wishful interpolation. Archimedes probably did find
a way to hurl fire. But this 2200-year-old death
ray was almost certainly imagined by a Byzantine
writer hundreds of years later and attributed to
Death rays relate to warfare the way perpetual
motion relates to energy production. They're
devices that make everything easy -- machines to
lift us above our dirty problems. We've dreamt of
technology like that ever since Archimedes. We
probably always will. Those dreams are a beginning,
but good engineering weds our dream to the world it
creates. Good engineers are interested in dreams
that can be taken out of the Uptown Theater and
held up to the bright light of a Saturday
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
D. L. Simms, Archimedes and the Burning Mirrors.
Technology and Culture, Vol. 18, No. 1,
I wrote this episode in 1989. Since then, Simms has
continued his work on Archimedes. Two new sources
on this subject are: D. L. Simms, Archimedes the
Engineer. History of Technology
(ed.G.Holiister-Short and F.A.J.L.James) Vol. 17,
1995 (London 1996) pp.45-113; and D. L. Simms,
Buffon's Burning Mirrors. Atti della Fondazione
Giorgio Ronchi, Anno LIX, no.5
settembre-ottobre, 2004, pp. 711-742.
An 18th century conception of a burning mirror
(From Le Entretiens Physiques d'Artiste et
d'Eudoxe, ou Physique Nouvelle en Dialogues, Qui
Renferme Précisément ce qui s'est
Découvert de plus Curieux & de plus
Utile dans la Nature
, Vol. III. 1745)
The Engines of Our Ingenuity is
Copyright © 1988-2004 by John H.