This document studies the stability of a gas cylinder embedded in a compressible liquid. It derives the dispersion relation that relates the growth rate of perturbations to wavenumbers and other parameters. For an incompressible liquid, the model is capillary unstable only for axisymmetric perturbations with small wavenumbers, and stable otherwise. Compressibility has a strong destabilizing effect and can cause the model to collapse. The capillary force has a mix of stabilizing and destabilizing effects depending on the mode of perturbation.