  We present HST GHRS and STIS observations of five QSOs that probe the
prominent high-velocity cloud (HVC) Complex C, covering 10% of the northern
sky. Based upon a single sightline measurement (Mrk 290), a metallicity
[S/H]=-1.05+/-0.12 has been associated with Complex C by Wakker et al.
(1999a,b). When coupled with its inferred distance (5<d<30 kpc) and
line-of-sight velocity (v=-100 to -200 km/s), Complex C appeared to represent
the first direct evidence for infalling low-metallicity gas onto the Milky Way,
which could provide the bulk of the fuel for star formation in the Galaxy. We
have extended the abundance analysis of Complex C to encompass five sightlines.
We detect SII absorption in three targets (Mrk 290, Mrk 817, and Mrk 279); the
resulting [SII/HI] values range from -0.36 (Mrk 279) to -0.48 (Mrk 817) to
-1.10 (Mrk 290). Our preliminary OI FUSE analysis of the Mrk 817 sightline also
supports the conclusion that metallicities as high as 0.3 times solar are
encountered within Complex C. These results complicate an interpretation of
Complex C as infalling low-metallicity Galactic fuel. Ionization corrections
for HII and SIII cannot easily reconcile the higher apparent metallicities
along the Mrk 817 and Mrk 279 sightlines with that seen toward Mrk 290, since
H-alpha emission measures preclude the existence of sufficient HII. If gas
along the other lines of sight has a similar pressure and temperature to that
sampled toward Mrk 290, the predicted H-alpha emission measures would be 900
mR. It may be necessary to reclassify Complex C as mildly enriched Galactic
waste from the Milky Way or processed gas torn from a disrupted neighboring
dwarf, as opposed to low-metallicity Galactic fuel.
