290 F. Waldo — Contributions to Dynamical Meteorology. 



given up to a statement of the author's views as to what effect 

 the shifting of the " cold " pole has on the oscillations of the 

 greater currents. A set of 57 diagrams illustrates in a very 

 acceptable manner, the results found by the author. 



No. 12. — Professor von Bezold occupies the chair of meteor- 

 ology at the University of Berlin, and he gives promise of 

 elevating the Prussian Meteorological Institution to as high a 

 rank among the great national meteorological services as that 

 of the Bavarian Institution among the smaller ones of similar 

 aims. Aside from his officially published papers, he has not 

 printed many memoirs on meteorological topics, but those he 

 has given us are of real value. 



In the present paper there is considered a question of me- 

 teorological physics that is of the very highest importance in 

 connection with the theories of storms, and of the greater 

 cyclonic and anticyclonic atmospheric movements. A number 

 of writers have treated the question of the application of the 

 mechanical theory of heat to atmospheric events, but in nearly 

 every case only such points have been considered as do not 

 take into account the addition or loss of heat during the ex- 

 pansion or compression. Such treatments of the convective 

 equilibrium of the atmosphere, the unstable equilibrium in the 

 case of tornadoes, and the foehn phenomena, have been made on 

 the supposition of adiabatic changes of condition. The author 

 thinks that the method of research which we owe to Clapeyron 

 and Carnot, and which has been so fruitful in the application 

 of the mechanical theory of heat to the study of machines, 

 should likewise be introduced into meteorological analysis. 



Hertz, in a paper in the Met. Zeits. 1884, has made a good 

 beginning in the direction in which the author leads us, but he 

 has considered only special cases ; and while his application of 

 the graphical method simplifies the question very much, yet it 

 does not take the place of the more general analysis when the 

 wide application of the principle is to be considered. Sprung, 

 also, in his " Lehrbuch " lays stress on the ideas given in 

 Hertz's paper. In the present paper the author explains at 

 length that the cooling and warming up in the case of ascend- 

 ing and descending currents in the atmosphere are to be con- 

 sidered only as a result of the work of expansion and compres- 

 sion, but not the work, which is used in raising the air, and is 

 obtained by the falling, when rising and falling masses did not 

 always belong to a system. The work of expansion and com- 

 pression must not be omitted from the calculations, as has been 

 done in the computations of Guldburg and Mohn. 



The ''equations of mixture" are then determined for the 

 four atmospheric stadia, viz : dry stratum, rain stratum, hail 

 stratum, and snow stratum. Then the equations of the char- 



