ON THE ENERGY OF STORMS MARGULES 569 



The assumptions of the approximate computation do not hold 

 good for h = 6000 meters ; but still the final formula gives very good 

 approximate values ; this is also true for systems having still greater 

 altitudes. 



§(26) If the overturning of the masses i and 2 takes place under 

 constant volume the computation proceeds in a perfectly similar 

 manner. These masses considered by themselves now form the 

 closed system to which equation (6**) of section 20 is to be 

 applied. The diminution of P will be greater than before and by so 

 much smaller will be the diminution of I, so that we obtain the 

 same value of V as for the overturning under constant pressure. 



We may also state the problem thus: During the overturning 

 the pressure at the upper boundary surface changes but has the 

 same value throughout all parts of this surface. If the change pro- 

 ceeds so slowly that no appreciable amount of kinetic energy is 

 thereby produced, then we again obtain the same equation (I) 

 as just now deduced for the velocity V. This is not a case of a 

 closed system. In plare of the equation (6**) we now have 



dK + (R) = -d (p + I) - B 



j ' Ph dh 



where the first term on the right hand refers only to the masses 1 and 

 2 and can be written in the form 



C p j(T -T')dm +B (h> p' h - h p h ) 



whereas the second term on the right results from the motion of the 

 movable piston. When p h is constant the sum of these right- 

 hand terms becomes C p f (T — T')dm. The case of constant 



volume corresponds to h' = h. 



We will now leave the two chambers system and compute the 

 available kinetic energy in a special case of continuous distribution 

 of temperature. 



§(27) Third analysis. The initial conditions are a continuous 

 horizontal distribution of temperature and a vertical diminution 

 of temperature corresponding to that of neutral equilibrium. 



We assume that the trough is a parallelopipedon of air having 

 a unit breadth and a length / along the horizontal axis of x, and that 



