J4& SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 51 



degree of latitude, 5 on the other hand, the center of the Siberian anti- 

 cyclone in January is in the latitude of about 6o° north. 



If we develop further the idea suggested in these few lines, we 

 perceive how easily and simply the average distribution of pressure 

 at the earth's surface can be summarized. 



The application of analogous methods of consideration to individ- 

 ual cases and the explanation of definite single phenomena by the 

 cooperation of the general circulation with local conditions may for 

 years to come well form one of the most important subjects for 

 investigations. 



A complete and rigorous solution of such questions will indeed 

 offer very great difficulties and it cannot yet be foreseen when that 

 will be successful. Hence at first we must satisfy ourselves with 

 considering especially simple cases from the point of view just 

 explained. 



But first it appears to be important to establish simple criteria 

 showing whether the temperature and moisture conditions alone 

 suffice to explain the facts of very definite phenomena or, still 

 better, those of any given cases of cyclones or anticyclones, or 

 whether and to what extent we have to consider the cooperation of 

 motions whose causes lie outside the given whirlwind or at least 

 outside the portions immediately considered. 



The object of the following lines is to make a contribution in this 

 direction, so that in general it has the same object as the above- 

 mentioned investigations of Hann. But while in the latter the 

 main feature consisted in the discussion of data of observation 

 where the temperature conditions especially were considered; on 

 the other hand, here theoretical considerations will be carried out 

 and especially will the atmospheric pressure and the wind be con- 

 sidered. 



The question as to the influenceof thegeneral atmospheric circula- 

 tion on the processes within a cyclone, always assuming a stationary 

 or steady condition may be formulated as follows: 



"Does the actually existing distribution of pressure and tempera- 

 ture suffice to completely explain the simultaneous observed motions 

 or does it not?" 



Or, in other words, 



5 Sprung: Lehrbuch der Meteorologie; Hamburg, 1885, p. 193. In the 

 following pages I shall frequently cite this work instead of the original mem- 

 oirs, since frequently the latter can be obtained only with difficulty and since 

 the references will be found in the work of Sprung. 



8 Hann: Atlas of Meteorology. Plate No. VII, Gotha, 1887. 



