XVII 

 ON THE THEORY OF CYCLONES 



BY PROF. DR. WM. VON BEZOLD 



[Sitzungsberichte of the Berlin Academy, 1890, pp. 12Q5-131J. Translated 

 from Gesammelte Abhandlnngen, jpo6, pp. 284.-305) 



If one follows up the meteorological literature of recent years he 

 will not deny that a complete reversal has gradually taken place in 

 the fundamental views as to atmospheric movements. 



Whereas under the domination of the old trade wind theory 

 nearly all these movements were considered as consequences of the 

 interchange of air going on between the poles and the equator and 

 nearly all individual processes were sought to be explained from 

 this point of view, we now go to the opposite extreme since the 

 establishment of the so-called "Modern Meteorology." 



Since by means of the daily weather charts we have learned the 

 importance that attaches to the areas of high and low atmospheric 

 pressure, we now imagine that the old point of view may at the 

 most still have some value only in explaining the processes in the 

 tropical zones, but that in higher latitudes only local warming and 

 cooling, as also the condition of the moisture, are the controlling 

 feature in the formation of cyclones and anticyclones, and therefore 

 of all the weather phenomena. 



Previously we considered the low pressure in the interior of a cy- 

 clone as only a consequence of the whirling motion produced by the 

 cooperation of the equatorial and the polar currents. Subsequently, 

 on the other hand, we thought of the whirling motion as exclusively 

 the consequence of the low pressure which itself had its origin in the 

 local conditions just mentioned. We need not -go into detail to 

 show how much of truth there was in this newer view and how much 

 our knowledge was advanced by it, but it cannot be denied that we 

 went too far when we thought that in it we had the key to the expla- 

 nation of all weather phenomena. 



Absorbed by the many results offered by the study of individual 

 phenomena from the new point of view we have almost entirely 

 lost sight of the general circulation. However, individual investiga- 

 tors have made distinguished exceptions to this and William Ferrel 



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