  We present a magnetometer based on optically pumped Cs atoms that measures
the magnitude and direction of a 1 $\mu$T magnetic field. Multiple circularly
polarized laser beams were used to probe the free spin precession of the Cs
atoms. The design was optimized for long-time stability and achieves a scalar
resolution better than 300 fT for integration times ranging from 80 ms to 1000
s. The best scalar resolution of less than 80 fT was reached with integration
times of 1.6 to 6 s. We were able to measure the magnetic field direction with
a resolution better than 10 $\mu$rad for integration times from 10 s up to 2000
s.
