Today, we reinvent defensive fortifications. 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.
What should forts look like?
The great American forts of the 19th century took a
form most of us have forgotten. The towers and
loopholed overhangs on the old Medieval castles
could not stand up to cannon fire. So, by 1800,
forts presented a simpler and lower profile -- a
long thin line of wall.
Most 19th-century forts were square or pentagonal,
with bastions on each corner. Bastions are
spade-shaped widenings of the corners. They let
defenders fire parallel to the walls. Bastions gave
those old forts the shape of great stone
snowflakes.
Fort Sumter, out in Charleston Bay, was five-sided,
but it sat on the tip of an island. Water came
right up to four of its walls. Only the fifth wall
needed the protection of bastions.
The Civil War began with the Confederacy pouring
40,000 artillery rounds into Fort Sumter. They
killed no one, but the Fort was beginning to crack.
So the Union surrendered.
A prophetic siege took place in Europe a year
later. At the Battle of Duppel, 6000 ill-equipped
Danes built a long fortified trench and held off
18,000 well-equipped Prussians. Instead of
crumbling under Prussian artillery fire, the Danes'
protective dirt just flew into the air and fell
back down. The Prussians won, but it took two
months, and it cost far too many lives.
At the same time in America, the Union was rolling
a new breed of long-range rifled cannons into
place. Those guns could sit outside the range of
the old smooth-bore Confederate artillery. They
quickly pounded the major Southern forts into
gravel.
Then, in 1863, the Union set up on Morris Island in
Charleston Bay, outside the range of Fort Sumter's
guns. They commenced to hammer Sumter into gravel
as well. But the Confederate troops simply shoveled
dirt and sand into the holes and burrowed in under
it.
In a few days the combination of Federal guns and
Confederate ingenuity had turned the fort into the
same sort of breastworks that had protected the
Danes at Duppel. Period photographs of Sumter show
what appears to be total destruction. Yet it was in
fact an impenetrable redoubt. Accident had taught
the South just as it had the Danes. The North never
did take the fort.
And we're left with a remarkable example of how
technology informs us. Masonry was no protection
against the new rifled cannons, but pulverized
walls were. Southern ingenuity was alert to that
lesson. By war's end the South had reinvented
defensive fortifications. The old masonry forts
lingered another half century, but they never again
played any important role in war.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
Robinson, W.B., American Forts: Architectural
Form and Function. Urbana, IL: University of
Illinois Press. (Published for the Amon Carter Museum
of Western Art, Fort Worth, TX), 1977.
See also Episode 108.
I'm grateful to Tom McConn, UH History Department,
for his counsel.
From the 1832 Edinburgh
Encyclopaedia
A typical early 19th-century pentagonal
fortification
Image courtesy of Sims
McCutchan
Stereopticon photo of a WW-1 battlefield: No more
forts.
The Engines of Our Ingenuity is
Copyright © 1988-1997 by John H.
Lienhard.
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