  We have compiled a large sample of O, Ne, S, Cl, and Ar abundances which have
been determined for 85 galactic planetary nebulae in a consistent and
homogeneous manner using spectra extending from 3600-9600 Angstroms. Sulfur
abundances have been computed using the near IR lines of [S III] 9069,9532
along with [S III] temperatures. We find average values, expressed
logarithmically with a standard deviation, of log(S/O)=-1.91(+/-.24),
log(Cl/O)=-3.52(+/-.16), and log(Ar/O)=-2.29(+/-.18), numbers consistent with
previous studies of both planetary nebulae and H II regions. We also find a
strong correlation between [O III] and [S III] temperatures among planetary
nebulae. In analyzing abundances of Ne, S, Cl, and Ar with respect to O, we
find a tight correlation for Ne-O, and loose correlations for Cl-O and Ar-O.
All three trends appear to be colinear with observed correlations for H II
regions. S and O also show a correlation but there is a definite offset from
the behavior exhibited by H II regions and stars. We suggest that this S
anomaly is most easily explained by the existence of S^+3, whose abundance must
be inferred indirectly when only optical spectra are available, in amounts in
excess of what is predicted by model-derived ionization correction factors.
Finally for the disk PNe, abundances of O, Ne, S, Cl, and Ar all show gradients
when plotted against galactocentric distance. The slopes are statistically
indistinguishable from one another, a result which is consistent with the
notion that the cosmic abundances of these elements evolve in lockstep.
