  Ultra-cold sodium molecules were produced from an atomic Bose-Einstein
condensate by ramping an applied magnetic field across a Feshbach resonance.
More than $10^5$ molecules were generated with a conversion efficiency of
$\sim$4%. Using laser light resonant with an atomic transition, the remaining
atoms could be selectively removed, preventing fast collisional relaxation of
the molecules. Time-of-flight analysis of the pure molecular sample yielded an
instantaneous phase-space density greater than 20.
