  Scattering and absorption properties at optical and ultraviolet wavelengths
are calculated for an interstellar dust model consisting of carbonaceous grains
and amorphous silicate grains. Polarization as a function of scattering angle
is calculated for selected wavelengths from the IR to the vacuum UV. The
widely-used Henyey-Greenstein phase function provides a good approximation for
the scattering phase function between ~0.4 and 1 micron, but fails to fit the
calculated phase functions at shorter wavelengths and longer wavelengths. A new
analytic phase function is presented. It is exact at long wavelengths, and
provides a good fit to the numerically-calculated phase function for lambda >
0.27um.
  Observational determinations of the scattering albedo and <cos(theta)> show
considerable disagreement, especially in the ultraviolet. Possible reasons for
this are discussed.
