  We present preliminary results from a deep observation lasting almost 200 ks,
of the centre of the Perseus cluster of galaxies around NGC 1275. The X-ray
surface brightness of the intracluster gas beyond the inner 20 kpc, which
contains the inner radio bubbles, is very smooth apart from some low amplitude
quasi-periodic ripples. A clear density jump at a radius of 24 kpc to the NE,
about 10 kpc out from the bubble rim, appears to be due to a weak shock driven
by the northern radio bubble. A similar front may exist round both inner
bubbles but is masked elsewhere by rim emission from bright cooler gas. The
continuous blowing of bubbles by the central radio source, leading to the
propagation of weak shocks and viscously-dissipating sound waves seen as the
observed fronts and ripples, gives a rate of working which balances the
radiative cooling within the inner 50 kpc of the cluster core.
