Today, we say goodbye to lighthouses and cabooses.
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.
Our railways are caught in a
funny debate these days. The caboose is a kind of
moving observation tower -- a way of seeing over
and beyond a railway train. Electronic safety
systems are making them obsolete, but cabooses are
so much a part of the romance of railroading that
no one wants to give them up. And that's how it is
with lighthouses, too. Lighthouses and cabooses are
woven into the romance of the rails and of the sea.
Lighthouses are used at night to mark any danger to
shipping -- sea-crossings, rocks, major landfalls.
The distance from the light to the horizon depends
on how high the lamp is, so height is important. A
15-foot light can be seen for 4½ miles. A
120-foot light is visible over 12 miles away,
and so forth.
That's why the Pharos at Alexandria was so big. One
of the seven wonders of the ancient world, it held
a huge bonfire 400 feet in the air. And, like it,
lighthouses down through centuries were usually
tall masonry towers mounted on shore -- maybe on
shoreline cliffs -- burning wood or olive oil and,
later, coal or candles. It was a pretty static
technology. Rotating beams weren't invented until
1611. Reflectors weren't added until 1763. The
first lens was introduced less than 200 years ago.
Lighthouse construction began to move again in
1698, when the English had to warn ships away from
the Eddystone rocks, 14 miles southwest of
Plymouth. You've probably heard the old folk song:
Oh, me father was the keeper of the Eddystone
Light,
And he slept with a mermaid one fine night.
And from this union there came three,
A porpoise and a porgy -- and the other was me.
Well, building the Eddystone light was a
terrible job. It had to be erected right at sea
level, where it was hammered by waves. The first one,
made of wood, lasted five years. The next, made of
wood and iron, burned down after 47 years. The third,
made in 1759 with a new kind of interlocking stone
construction, stood. It wasn't replaced until 1881,
and that Eddystone light is still with us.
But now radar, and sonar, and electronic buoys are
putting an end to the lighthouse. We'll have to
live in a world without cabooses on trains -- and
without those beautiful storm-beaten minarets to
call the weary sailor home.
The siren attraction of the lighthouse, like other
technology past -- and, I suppose, like much
technology yet to come -- is that good technology
is contrived to fulfill human need. That's why it
satisfies more than function. It expresses what's
inside us. Good technology has symbolic as well as
functional power. And that's why we're so loath to
say goodbye to it.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
