  We present a generalized phenomenological formalism for analyzing the
original E\"{o}tv\"{o}s experiment in the presence of gravity and a generic
"5th force." To date no evidence for a 5th force has emerged since its presence
was suggested by a 1986 reanalysis of the 1922 publication coauthored by
E\"{o}tv\"{o}s, Pek\`ar, and Fekete (EPF). However, our generalized analysis
introduces new mechanisms capable in principle of accounting for the EPF data,
while at the same time avoiding detection by most recent experiments carried
out to date. As an example, some of these mechanisms raise the possibility that
the EPF signal could have arisen from an unexpected direction if it originated
from the motion of the Earth through a medium.
