Today, we make noise. 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.
In 1867, the first primitive
steam-powered fog siren was installed at the
lighthouse on Sandy Hook, New Jersey. Sandy Hook
reaches out almost halfway across New York Bay
toward Brooklyn, and it poses a serious threat to
shipping in and out of New York City.
The light served warning when it could be seen.
But, in fog, Sandy Hook could not be seen. It had
to be heard; and this new machine was very audible.
Previously, ships were warned off the rocks by
repeated cannon fire. That became hopelessly
expensive and inconvenient as shipping trade
increased.
Historian Michael Lamm tells how, five years after
that first installation, the Sandy Hook Lighthouse
acquired one of the new steam sirens just patented
by the Brown Brothers in New York.
The heart of their siren was a rotating
slotted cylinder alternately opening and closing a
passageway to either steam or compressed air. Its
rotation gave the desired frequency, and it sat in
the throat of a long, large horn.
Those sirens were powerful, and most were less
isolated than Sandy Hook. In 1900, a newspaper
called a Rhode Island siren "the greatest nuisance
in the history of the state." Near a Connecticut
fog siren, people found that chicks were dying
before they hatched.
While people who lived by those large coastal
sirens grew nervous, lost weight, and watched as
sound curdled their milk, the technology raced on.
An amateur organ-builder named Robert Hope-Jones
created a tone generator called a diaphone for the
Wurlitzer Organ Company. Then he adapted it into
the classical low-frequency foghorn sound that we
all know from old movies.
That design modified over the years. Meanwhile,
World War II required higher-pitched sirens to
operate in clear air. We needed them to warn, not
of rocks, but of enemy bombers. The Chrysler
Corporation built one driven by a 140-horsepower
eight-cylinder automobile engine. Same basic sound
production, but far more powerful -- almost twice
as earsplitting as a jet engine.
The pitch of an air raid siren was near the
concert A used by the
oboe to tune an orchestra. But there the comparison
ends. Come within a hundred feet of one, and
ear-protectors give scant protection. The ground
shakes, and your vision blurs.
The big, loud sirens still exist. In Hawaii, they
warn of Tsunamis. Other
big sirens are for other big dangers. And we think
of the original Sirens. They did not repel; they
attracted. Circe warned Odysseus about the legendary
Sirens:
You will come to the Sirens, enchanters of all
mankind. They sit in their meadow, but the beach
before it is piled with boneheaps of men now rotted
away ...
None of that enchantment in today's sirens. They
mean danger, just as surely as they did for
Odysseus. But there is no longer any come-hither
message in the few of those great, wailing sirens
that still remain to be heard.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
Lamm, M. Feel the Noise: The Art and Science of
Making Sound Alarming. Invention and
Technology, Winter 2003, pp. 22-27.
For more on lighthouses, see Episode 1523.
The Engines of Our Ingenuity is
Copyright © 1988-2003 by John H.
Lienhard.
