That is an interesting question, all right.  It is true that there
is somewhat less flicker in fluorescent lighting at 60 HZ than at 50 HZ,
but fluorescent lamps weren't invented until 1938 so that probably wasn't
a factor.

        I am totally guessing, here, but I imagine that the European and
most of the rest of the world's choice of 50 HZ is based on the Metric
system and its use of decimal measures plus practical engineering
considerations relating to how to build generators that would run
most efficiently.

        Our system of 60 HZ line frequency may be based on a continuation
of the concept of time with 60 minutes in an hour, 60 seconds in a minute,
and 60 cycles per second.  It makes as much sense or as little sense as
anything else.

        While this is quite off topic, it is interesting to remember that
the engineers of the 1890's were grappling with these questions with the
same intensity that today's engineers are devoting to some of the thorny
problems we have now.  It's all a compromise between what we want to happen
and what the prevailing technology will allow us to do.

        Let's be thankful that something like 500 HZ wasn't practical back
then.  We used to have a 400 HZ motor generator set powering the IBM main
frame at this site and the 400 and 800 HZ whines from anything using power
from the motor generator sort of drilled in to one's nerves by the end of the
day.  A 400 HZ 115-volt signal is a dandy way to test the shielding on any
audio systems, also.:-(

Martin McCormick WB5AGZ  Stillwater, OK 36.7N97.4W
OSU Center for Computing and Information Services Data Communications Group