  We have designed and tested an atomic vectorial magnetometer based on the
analysis of the coherent oscillatory transients in the transmission of resonant
laser light through a Rb vapor cell. We show that the oscillation amplitudes at
the Larmor frequency and its first harmonic are related through a simple
formula to the angles determining the orientation of the magnetic field vector.
The magnetometer was successfully applied to the measurement of the ambient
magnetic field.
