I wonder whether Prentice was orienting his coil in any particular way.
What I'm thinking of here is Michael Theroux's (or one of the BSRF
guys) claim that early telegraph systems drove impossibly long lengths
of wire with small batteries because the engineers intuitively laid the
cable along something like a ley system. They used to have an article
on the web at www.borderlands.com. I don't know whether it's still
there or whether they've replaced it with articles from a newer issue
of their magazine. I figure they must be onto *something* if for no
other reason than they've managed to write a 10-volume encyclopedia of
the phenomenon!
-- A good traveller has no fixed plans and is not intent on arriving. --Lao Tzu