Jonathan Thornburg wrote in message
...

In message , I wrote
| [[Mod. note -- There's a famous argument by (I think) Dirac
| (it's summarized in Jackson's E&M textbook) that the existence of
| even a single magnetic monopole in the universe would explain
| (require for consistency) the quantization of electric charge.
| -- jt]]

In article ,
greywolf42 wrote:
On the other hand, the existence of magnetic monopoles would contradict
Maxwell's original derivation of "Maxwell's equations", in "On Physical
Lines of Force", 1861. MM's were "added" to Maxwell's equations in the
name
of "symmetry" in the '60's

============

Dirac's papers on this were published in 1931 and 1948. The argument
is described (and full citations to Dirac's papers are given) in
sections 6.11 and 6.12 of the book I mentioned before,

@Book{Jackson99,
author = "John David Jackson",
title = "Classical Electrodynamics",
edition = "3rd"
publisher = "Wiley",
address = "New York",
year = "1999",
isbn = "0-471-30932-X"
}

Quoting from the opening paragraph of section 6.11,

"Dirac's argument, outlined below, is that the mere existence
of one magnetic monopole in the universe would offer an
explanation of the discrete nature of electric charge."

There was no need for you to snip the essence of my post, and you should not
snip without marking same. The rest of my sentence was:

", and were big in the '70's -- including a few claims of observation.
Those observations were proven incorrect, and the fad has since died down."

While I was unaware that Dirac was the first to bring up magnetic monopoles
in the interests of symmetry, the faddish years were definitely the 60's and
70's. And despite Dirac, symmetry, and 20 years of effort -- magnetic
monopoles remain fictional. Constistent with Maxwell's derivation -- and
inconsistent with QM and Dirac.

greywolf42
ubi dubium ibi libertas