Andy writes:

I remember from 50 or so years ago reading a copy of POP
electronics, or
maybe ELEC illustrated, which featured a couple of young boys named
Carl
and Jerry and the stuff they messed about with each month. Kind of
like
a "Mr Wizard" story.....

One of the articles was winding a coil of wire around a plastic
bottle of
water and exciting it , then watching the output from the coil as "the
water
molecules oscillated"...... I don't remember the details, but they
called
the affair a "differential proton magnetometer", and used it to
measure
magnetic fields....

Does anyone else here remember this article, and do you have any
means
to clarify the method, and possibly the practice ?

Being retired, I have a lot of time on my hands to do experiments,
especially
simple ones, and I thought it would be a hoot to explore this for a
day or
two. However, I don't remember enough details to be able to put
together
a proof of concept in my workshop...

Thanks in advance for anything anyone here can suggest...

Andy W4OAH in Eureka, Texas