THE ULTRAVIOLET-ABSORPTION SPECTRUM OF 3C-273

We identify six Ly-alpha absorption systems with equivalent widths greater than 0.2 angstrom in the ultraviolet spectrum of the nearby quasar 3C 273, more than expected on the basis of extrapolations of the observed number of Ly-alpha clouds seen at large redshifts. Two Ly-alpha lines appear to be produced by gas in the Virgo Cluster or by the halos of galaxies associated with the Virgo Cluster. We also detect all the interstellar absorption lines that are expected on the basis of abundance, atomic physics, and ionization considerations.