THE MILLIARCSECOND STRUCTURE OF THE QUASAR 3C-279

High resolution VLBI maps of the quasar 3C 279 are presented for five epochs between 1987.42 and 1990.17 at frequencies 10.7 and 22.2 GHz. A new structural feature at 10.7 GHz, correlated with multifrequency ou tbursts, is identified near the nucleus at epoch 1989.3. At least two components are moving with apparent superluminal speed beta(obs) almos t-equal-to 2.8h-1 relative to the nucleus. The VLBI structure can be e xplained by a relativistic beaming model; we deduce a jet angle to the line of sight of 37-degrees less-than-or-equal-to phi less-than-or-eq ual-to 39-degrees and a Lorentz factor gamma greater-than-or-equal-to 3. The estimated apparent opening angle is 33-degrees +/- 5-degrees. U sing X-ray measurements, we determine a lower limit to the Doppler fac tor delta greater-than-or-equal-to 1.1, indicating moderate relativist ic bulk motion. We explain the continuous variation in beta(obs) and P .A. from one component to another as resulting from precession of the jet with a period of approximately 30 years.