The instability of a layer of fluid heated below and subject to Coriolis forces. II

The theory described in an earlier paper (Chandrasekhar 1953 b) is extended in a manner which enables the determination of the critical Rayleigh number for the onset of thermal instability of a layer of fluid heated below and subject to rotation via a marginal state of purely oscillatory motions. Numerical results are derived for the case when the ratio of the kinematic viscosity to the thermometric conductivity has a value (= 0.025) equal to that for mercury at ordinary temperatures. A comparison of the theoretical results obtained in this paper with those of experiments will be found in the following paper by Fultz & Nakagawa