In the former paper the present authors calulated the potential energy of vertical air column in which a heavy cold mass lies on a warm mass, assuming that each dry mass has a uniform lapse-rate smaller than the dry adiabatic and the temperature is discontinuous only at the surface of separation of the two masses, and further the air column extends infinitely both upwards and downwards. In the present paper is presented the new condition that the same air column as in the former paper stands on the ground and the height of the surface of separation of the two masses is constant. In this case the two types of overturning occur. Namely, when the jump of temperature at the surface of separation of the two masses is small, the overturning of air is the same as in the former paper and the disturbance is confined to the upper atmosphere, but, when the jump of temperature is large, the lower par_??_t of the cold mass subsides on the ground in overturning. The result of numerical computation shows that the conspicuous discontinuity of labile energy occurs in passing from the latter type of overturning to the former. It is noticeable here that the lower temperature of cold mass does not always mean the larger labile energy.