  Following some previous papers, we continue in this paper to give proof of
the analogy between the acoustic world and the electromagnetic world. Hence we
derive the expressions for: the scattering-scattering force (the
electro-acoustic force) between the bubbles found in the inner cluster and the
bubble found out of the cluster, the scattering-absorption force (the
gravito-acoustic forces) between the bubbles found in the inner cluster, the
gravito-acoustic forces between the cluster as a whole and an outer bubble, the
temperature corresponding to the translational motion of the bubbles in the
inner cluster and the average pressure of the acoustic radiation. The results
of our calculus led us to find out that the absolute value of the average
pressure of the acoustic radiation around a bubble is equal to the density of
the energy of the electro-acoustic field, Eq. (10). This is the most important
result of this paper. These densities are the densities of the energy
corresponding to the oscillation of the bubble (the liquid around the bubble)
that are involved in the interaction phenomenon between two oscillating
bubbles. We have also demonstrated that the gravito-acoustic forces, at
resonance, between the bubbles inside the cluster, generated by the absorption
of energy in the bubbles, are proportional to the square of the virtual masses
of the bubbles, Eqs. (29) and (30).
