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
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
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
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
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
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
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
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
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.