We report the determination of high-accuracy radial velocities for 299 members of the globular cluster M92 using the Hydra multi-object spectrograph on the WIYN telescope .
We have concentrated on stars outside of the central region of the cluster , located up to 14 \farcm 4 from the cluster center .
Candidate members were selected for spectroscopy based on a photometric metallicity index determined from 3-band Washington photometry , also obtained with the WIYN telescope .
The median error in the velocities is 0.35 km s ^ { -1 } .
We find the heliocentric radial velocity of the cluster to be -121.2 \pm 0.3 \mbox { km \thinspace s$ { } ^ { -1 } $ } .

We have used an improved Bayesian analysis to determine the velocity dispersion profile of M92 .
The most probable profile is a cored power-law with a scale radius of 2′ , velocity dispersion at 1′ of 6.3 km s ^ { -1 } and outer power-law with slope -0.6 .
We have also reanalyzed the M15 radial velocities of Drukier et al .
( 15 ) and find that a pure power-law with a 1′ velocity dispersion of 8 km s ^ { -1 } and slope -0.5 , and the combination of a power-law with slope -0.4 and scale of 7.5 km s ^ { -1 } inside 9′ and a dispersion of 4 km s ^ { -1 } outside , are equally likely .
In both clusters there is evidence that the samples include escaping stars .
We present results from a GRAPE-based N-body simulation of an isolated cluster that demonstrates this effect .
We suggest additional tests to determine the relative importance of tidal heating and stellar ejection for establishing the velocity field in globular cluster halos .