Today, we just miss fame. 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.
Josef Loschmidt was born into a poor Bohemian
peasant family in 1821. With the help of a village priest and the
Catholic Church he managed to gain an education in science. He worked
for a while in the new chemical process industry where he invented a way
to produce nitrate. Then that process turned out to have been known
fifty years earlier. That was an odd hint of things to come.
For several years, Loschmidt tried to set himself up in business,
only to go bankrupt. So, at the age of 33, he gave up on business and
went back to theoretical physics. There he made many contributions, all
of which became overshadowed by the works of others. Here's one:
He soon published a book on chemistry in which he discussed benzene,
a compound that'd baffled people. They couldn't see how the atoms were
arranged. It was he who first saw they had to form a ring. But his
description of how the atoms linked to each other was incorrect. Soon
after, chemist Friedrich
Kekulé got it right, and Loschmidt's contribution was pretty much
forgotten.
The great puzzles of the mid nineteenth century drew Loschmidt in --
questions like "How big is a molecule?" Ask yourself how you'd answer
that one -- obviously not with a ruler. Loschmidt realized he could
deduce the size of molecules from two kinds of information. One was a
relation connecting the size of gas molecules to the distance they
travel between collisions. The other was the packed volume of molecules
in a cold liquid. He correctly found that a small molecule is around one
nanometer in size.
And that led him to put flesh and blood on another idea. The Italian,
Romano
Amadeo Carlo Avogadro, had suggested that all gases have the
same number of molecules in a given volume. Loschmidt figured out how
many molecules that would be.
His number was high but then, we're still honing it. Some people
argue that we should call the number of molecules per gram-mole The
Loschmidt number instead of Avogadro's
Number. This is not really a priority debate. After all, we
know exactly what each person contributed. Still, it's Avogadro whom we
remember.
Loschmidt contributed to Maxwell's and Boltzman's
work on thermodynamics. His electromagnetic studies now bear the names
of people who completed them -- like Hertz and Hall. When Loschmidt died
in 1895, Boltzmann wrote, "His work forms a mighty cornerstone that will
be visible as long as science exists."
Boltzmann was right about the cornerstone part. But not the
visibility. Few of us who've used Avogadro's Number have even heard of
Loschmidt. Yet, while the message seems to be that life isn't fair, this
is not a sad story by any means.
Loschmidt was clearly more interested in science as a process than as
a way to become famous. By the way, he married for the first time at the
age of 66, to his housekeeper. Soon after, his only child was born.
I'm John Lienhard, at the University of Houston, where we're
interested in the way inventive minds work.
(Theme music)
W. Böhm, Loschmidt, Johann Joseph. Dictionary of Scientific
Biography (C.C. Gilespie, ed.). New York: Charles Scribner's Sons,
1970-1980. Vol. ??, pp. 507-511.
A. Bader and L. Parker, Joseph Loschmidt, Physicist and Chemist.
Physics Today, March 2001. On line at: http://www.physicstoday.org/pt/vol-54/iss-3/p45.html
See also, http://dbhs.wvusd.k12.ca.us/Chem-History/Loschmidt-1865.html
I am most grateful to WSHU listener James W. Cooper for calling my
attention to Loschmidt.
An Austrian stamp honoring J. Josef Loschmidt
The Engines of Our Ingenuity is
Copyright © 1988-2003 by John H. Lienhard.
