  We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the
sightline toward the Seyfert 1 galaxy Markarian 876, which passes through high
velocity cloud (HVC) complex C. This sight line demonstrates the ability of
FUSE to measure ionic absorption lines in Galactic HVCs. High velocity
absorption is clearly seen in both members of the O VI doublet. This is the
first detection of O VI in a neutral hydrogen HVC. One component of HVC complex
C is resolved in multiple Fe II lines from which we derive N(Fe II)/N(H I)=0.48
(Fe/H)_solar. This value of N(Fe II)/N(H I) implies that the metallicity of
complex C along this sightline may be higher than that along the Mrk 290
sightline (0.1 solar) found by Wakker et al. (1999). On the other hand, if the
metallicity of complex C is also 0.1 solar along this line of sight, the
observed value of N(Fe II)/(N(H I) suggests there may be a significan t amount
of H+ along the line of sight. In any case, little, if any, iron can be
depleted into dust grains if the intrinsic metallicity of complex C is
subsolar. Absorption from complex C is also seen in C II, N I, and N II, and
upper limits based on non-detections can be determined for Ar I, P II, and Fe
III. Although molecular hydrogen in the Milky Way is obvious in the FUSE data,
no H_2 absorption is seen in the high velocity cloud to a limit
N(H_2)<2.0x10^14 cm^-2. Future FUSE observations of extragalactic objects
behind Galactic high velocity clouds will allow us to better constrain models
of HVC origins.
