  We observed the HH 211 jet in the submillimeter continuum and the CO(3-2) and
SiO(8-7) transitions with the Submillimeter Array. The continuum source
detected at the center of the outflow shows an elongated morphology,
perpendicular to the direction of the outflow axis. The high-velocity emission
of both molecules shows a knotty and highly collimated structure. The SiO(8-7)
emission at the base of the outflow, close to the driving source, spans a wide
range of velocities, from -20 up to 40 km s^{-1}. This suggests that a
wide-angle wind may be the driving mechanism of the HH 211 outflow. For
distances greater than 5" (1500 AU) from the driving source, emission from both
transitions follows a Hubble-law behavior, with SiO(8-7) reaching higher
velocities than CO(3-2), and being located upstream of the CO(3-2) knots. This
indicates that the SiO(8-7) emission is likely tracing entrained gas very close
to the primary jet, while the CO(3-2) is tracing less dense entrained gas. From
the SiO(5-4) data of Hirano et al. we find that the SiO(8-7)/SiO(5-4)
brightness temperature ratio along the jet decreases for knots far from the
driving source. This is consistent with the density decreasing along the jet,
from (3-10)x10^6 cm^{-3} at 500 AU to (0.8-4)x10^6 cm^{-3} at 5000 AU from the
driving source.
