Just though I might outline a simple little tool I've constructed and used
for determining magnetic polarity. It is essentially a tiny compass and has
proved very useful. Take a lenght of thin wooden dowl, I used a meat skewer
which I think are made from bamboo, and fix a tiny magnet to the end in
such a manner that it can pivot freely on 2 copper needle points. The
magnet should be made as small as possible - a chip broken off a ceramic
magnet will do. My pivoting probe magnet is only about .5mm diameter and
1mm long, the north end painted red for visual ease. This simple tool
allows one to probe around in any magnetic field to provide a quick
indication of polarity. Very cheap and very useful.
Regards, Bill.