Richard Harrison wrote:
Distributed network theory is newer than lumped network theory but both
have been around plenty long enough to be well established.

Neumann didn't prove that the current through a coil is uniform.
He *assumed* it to be true as a simplification, so he could factor
out the current term from under the integral sign in one of Maxwell's
equations. Now Neumann's mathematical shortcut is being reported
here as a fact of physics. That's how well established it is.
--
73, Cecil http://www.qsl.net/w5dxp