Scott,
So, with the piano wire perhaps the particular factors I suggested as
possibly influencing the experiment weren't the ones that might have taken
place. My point is that there could be an unknown factor or factors which
may have contributed to the unexpected results of the experiment. With 4,250
of shaft and line to deal with, times two, plus the connecting tunnel, there
is room for error. I wasn't necessarily proposing that any one of these
suggestions was definitely a cause of any discrepancy, but that these were
only suggestions as to the possible kinds of unknown factors which may have
been at play. With #12 piano wire, perhaps one of the shafts penetrated or
came close to a loadstone pocket which caused a subtle flex in the line. I
don't think that the 4,250 feet of line (lines) was kept absolutely straight
from its creation to its arrival at the site, and was probably rolled up to
be transported. This initial coiling could cause a curling nature to the
line. Piano wire often remains somewhat curled after being unspooled. As
far as the 60 lb. weight being sufficient enough to keep it perfectly
straight, the 4,250 feet of wire probably weighed more than 60 pounds itself,
so it may not have been all that imposing. Remember, the 8 inch variance in
difference is only 1/6375th of the length of this line. A reletively small
ratio wouldn't you say? Anyway, I'm only suggesting that it might not take
all that much of a factor to sway a line 1/6375th of its length.
Just sharing thoughts on the matter.
Norlan