Hi, Bob:
Thank you for your info.
Just to clarify some points:

>bob:
>The north pole of a magnet (or a compass) is positive & seeks the north pole
>of the earth, which is negative, yes?

Actually its my understanding that when you use a compass, its the dial
which indicates ( I know we're off the list topic here) which is calibrated
North, etc, and the needle which points there.
The needle is attracted to point that way (North) by the fact that its point
is a (secretly) South pole.

I have never heard of magnetism being referred to as Positive or Negative.
Electricity, sure.

Incidently, we would all be in trouble if the earth's magnetic field
reversed.  Then what would be North?  All the compasses would point the
other way !!! Heeeellllllppppp.....

>  >[Also: wouldn't humans living on the northern hemisphere of the globe
> >experience the opposite polarity of magnetic field, than those, living on
>>the southern hemisphere??? So should one change the polarity of the pads (by
> >simply turning them to the other side) if changing the hemisphere you are
> >living in?]--Yes, that's my understanding

Well, that doesn't make sense either, unless you are saying that southern
hemisphere people are used to a different magnetic field?   Then we have a
problem for those travellers that "cross the line".  In actual fact, the
compass still points north in either hemisphere, so I guess we are safe
afterall (phew!!!_)

regards ;>)
Lynton