CXXXI. On the inhibition of convection by a magnetic field : II

Summary The analysis contained in an earlier paper on the inhibition of thermal convection by a magnetic field is extended to include the case when the impressed magnetic field (H) acts in a direction different from that of gravity (g). A variational method is described for determining the critical Rayleigh number for the onset of convection of any preassigned pattern ; and the result is established that when H and g act in different directions the convection which appears at marginal stability is in the form of rolls extended in directions parallel to the plane containing H and g.