Abstract
In a previous paper, the equilibrium of a plane horizontal layer of a viscous incompressible fluid of variable density po in the vertical (z) direction, which rotates uniformly at Ω rad./sec. about an axis making an angle θ with the vertical, was examined by the usual method of studying the initial behaviour of a small disturbance. The general properties of the ensuing hydrodynamical motion for any ρ0(z) and μ0(z) (μ0 being the coefficient of viscosity) were discussed. It was shown that in some circumstances, including the case θ = 0, the solution is characterized by a variational principle.