About E. J. Post(written by R.M.Kiehn and updated Mar 29, 2010)
Jan Post first worked in Holland with interests in crystallography as applied to
electromagnetic circuits. After working in industry for some time, he obtained
his Ph.D. degree and worked with the Schouten school and the Kramer's school in
Holland. In 2010 he will be 96, and yet is still very active in the field of
Physics. During his life he has had many "chats" (as he calls them) with many of
the great leaders of physics in the formative years of the quantum theory. His
first hand stories were always intriguing to me, when we went out for a simple
dinner of soup and salad at Alfred's restaurant in Houston.
His article on the Sagnac effect (Rev of Mod Physics) is what attracted
me to Jan's work. Later I discovered his monograph "The Formal Structure of
Electromagnetics" in which I saw the first definitive treatment of the Faraday
effect, and its non-reciprocity. This idea was what I had been searching for,
for if an experiment between EM and gravity was to work, it would have to
accumulate data - like the Faraday ratchet - in order to measure very small
The Jacksonian version of EM theory did not come close to explaining the
features that are so clear in Post's expose. I used to call the small book, the
"Tourist's Guide of Electromagnetism". The book is back in print now (Dover),
and no one interested in EM should be without it.
After reading the Sagnac article I called Post (in Massachesetts at the time)
and in a few weeks he showed up at my door in Houston, and stayed for several
years. He taught me tensors, and I introduced him to differential forms a la
Cartan. Over the years we have had many interesting interactions, and when I
discovered the 3-form A^G of electromagnetic spin (1974) I know that he finally
believed in the Cartan topological formulation of Electro-magnetism.
Jan and I used to have many heated discussions: a stubborn old Dutchman arguing
with a stubborn somewhat younger Polock.
CONTRIBUTIONS To Cartan's Corner by E. J. POST
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