Today, we draw more than salt from a salt mine. 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.
Salt has strong symbolic
importance in our lives because it's so important.
Tribes that live largely on milk and roasted meat
don't need it. But our grain-based diets do. We say
that nobility sits "above the salt," because when
salt was hard to come by, it was served only on the
upper tables. The Bible calls a serious promise "a
covenant of salt."
Most salt comes from either of two sources. The
ocean contains a mixture of sodium chloride and
other less palatable salts. Each comes out of
solution at a different stage of evaporation, so
you can extract usable table salt from the ocean.
Rock salt is the other source, and it's much purer.
It can either be mined directly from the earth or
be processed from the natural brines that form when
ground water flows through it. These high-grade
salts give us the term, "salt of the earth."
A huge natural deposit of rock salt lies just
outside the old Polish capital of Krakow in the
town of Wieliczka. Its name is part of the Polish
phrase, "The Great Salt Treasure." We know salt was
taken out of Wieliczka as early as 3500 BC.
Its first salt came from saline springs. When
Poland became a nation in the 10th century, these
springs were already a major salt center. The Poles
began underground mining of both rock salt and
brine in the late 13th century. For a while it was
the major natural resource of Poland.
The Wieliczka mine is still in use, and it's a
marvel. It reaches a thousand feet into the earth,
with 150 miles of tunnels. As the tunnels were left
behind, they spoke to the miners' imaginations.
Statues and tableaux have been carved from the
living salt. Kings, trolls, and saints loom out of
the darkness, larger than life. Chapels hewn in the
salt range from small prayer stations to a
cathedral lit by crystal chandeliers.
One great room is two hundred feet high, and its
floor opens onto a lake of brine. In WW-II, the
Germans used part of the mine to build airplane
engines, safe from allied bombs. A large sanatorium
lets respiratory patients breathe in the cool salt
air. 700 years of technique is on display in a
great museum of mining technology. The mine even
has its own post office.
Wieliczka is a monument, not just to human
ingenuity, but to the symbolic power of the salt of
the earth. It's a celebration of the unlimited
imagination that makes human enterprise worthwhile.
By the time you leave this strange fairyland, the
open air seems drab by comparison.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds