ON THE ENERGY OF STORMS MARGULES 



573 



The angle a that is included between the direction of the curve in 

 the vertical plane of xz and the horizon is given by the equation 



dF J 

 tan a = — — / 

 dx I 



I 



h-z C„\dT 



T, 



+ -* 



dx 



For n= i the angle a is a right angle. If n> i with stable equilib- 

 rium in each isolated column, and if x increases toward the right 

 hand, then the curves of equal entropy trend downward toward the 

 right. With increasing values of n the inclinations of the surfaces 

 of equal entropy to the level surfaces diminish very rapidly. 



If the horizontal increase of temperature is i° C. for 20 kilo- 

 meters or 



3 7\ 



dx 



= . 00005° Centigrade per meter 



we obtain the following respective sets of values: 



Even for very large horizontal temperature gradients, the sur- 

 faces of equal entropy are but slightly inclined to the level surfaces 

 when the vertical diminution of temperature in dry air is less than 

 0.9 per 100 meters. If now from such an initial condition the 

 masses pass adiabatically to the final stage then there is evidently 

 available a smaller amount of kinetic energy than in the cases where 

 the entropy surfaces are at first vertical. 



§(29) We now return to the two-chamber system. 



To find the final stage of two masses of air under constant pressure 

 with initial linear vertical diminution of temperature. 



If tlie vertical gradient of temperature within the masses 1 and 

 2 (fig. 4) is smaller than that for neutral equilibrium then the entropy 



