  We analysed the deep archival Chandra observations of the high-temperature
galaxy cluster Abell 2319 to investigate the prominent cold front in its core.
The main sharp arc of the front shows wiggles, or variations of the radius of
the density jump along the arc. At the southern end of the arc is a feature
that resembles a Kelvin-Helmholtz (KH) eddy, beyond which the sharp front
dissolves. These features suggest that KH instabilities develop at the front.
Under this assumption, we can place an upper limit on the ICM viscosity that is
several times below the isotropic Spitzer value. Other features include a split
of the cold front at its northern edge, which may be another KH eddy. There is
a small pocket of hot, less-dense gas inside the cold front, which may indicate
a `hole' in the front's magnetic insulation layer that lets the heat from the
outer gas to penetrate inside the front. Finally, a large concave brightness
feature southwest of the cluster core can be caused by the gasdynamic
instabilities. We speculate that it can also be an inner boundary of a giant
AGN bubble, similar to that in Ophiuchus. If the latter interpretation is
supported by better radio data, this could be a remnant of another extremely
powerful AGN outburst.
