  We present measurements of the column densities of interstellar DI and OI
made with the Far Ultraviolet Spectroscopic Explorer (FUSE), and of HI made
with the International Ultraviolet Explorer (IUE) toward the sdOB star Feige
110 [(l,b) = (74.09, -59.07); d = 179 +265 -67 pc; z = -154 +57 -227 pc]. Our
determination of the DI column density made use of curve of growth fitting and
profile fitting analyses, while our OI column density determination used only
curve of growth techniques. The HI column density was estimated by fitting the
damping wings of the interstellar Ly alpha profile. We find log N(DI) = 15.47
+/- 0.06, log N(OI) = 16.73 +/- 0.10, and log N(HI) = 20.14 +0.13 -0.20 (all
errors 2 sigma). This implies D/H = (2.14 +/- 0.82) x 10^-5, D/O = (5.50 +1.64
-1.33) x 10^-2, and O/H = (3.89 +/- 1.67) x 10^-4. Taken with the FUSE results
reported in companion papers (Moos et al. 2001) and previous measurements of
the local interstellar medium, this suggests the possibility of spatial
variability in D/H for sight lines exceeding ~100 pc. This result may constrain
models which characterize the mixing time and length scales of material in the
local interstellar medium.
